update ceph source to reef 18.1.2

[ceph.git] / ceph / src / jaegertracing / opentelemetry-cpp / third_party / prometheus-cpp / 3rdparty / civetweb / src / third_party / duktape-1.8.0 / src-separate / duk_js_compiler.c

/*
 *  Ecmascript compiler.
 *
 *  Parses an input string and generates a function template result.
 *  Compilation may happen in multiple contexts (global code, eval
 *  code, function code).
 *
 *  The parser uses a traditional top-down recursive parsing for the
 *  statement level, and an operator precedence based top-down approach
 *  for the expression level.  The attempt is to minimize the C stack
 *  depth.  Bytecode is generated directly without an intermediate
 *  representation (tree), at the cost of needing two passes over each
 *  function.
 *
 *  The top-down recursive parser functions are named "duk__parse_XXX".
 *
 *  Recursion limits are in key functions to prevent arbitrary C recursion:
 *  function body parsing, statement parsing, and expression parsing.
 *
 *  See doc/compiler.rst for discussion on the design.
 *
 *  A few typing notes:
 *
 *    - duk_regconst_t: unsigned, no marker value for "none"
 *    - duk_reg_t: signed, < 0 = none
 *    - PC values: duk_int_t, negative values used as markers
 */

#include "duk_internal.h"

/* if highest bit of a register number is set, it refers to a constant instead */
#define DUK__CONST_MARKER                 DUK_JS_CONST_MARKER

/* for array and object literals */
#define DUK__MAX_ARRAY_INIT_VALUES        20
#define DUK__MAX_OBJECT_INIT_PAIRS        10

/* XXX: hack, remove when const lookup is not O(n) */
#define DUK__GETCONST_MAX_CONSTS_CHECK    256

/* These limits are based on bytecode limits.  Max temps is limited
 * by duk_hcompiledfunction nargs/nregs fields being 16 bits.
 */
#define DUK__MAX_CONSTS                   DUK_BC_BC_MAX
#define DUK__MAX_FUNCS                    DUK_BC_BC_MAX
#define DUK__MAX_TEMPS                    0xffffL

/* Initial bytecode size allocation. */
#define DUK__BC_INITIAL_INSTS 256

#define DUK__RECURSION_INCREASE(comp_ctx,thr)  do { \
                DUK_DDD(DUK_DDDPRINT("RECURSION INCREASE: %s:%ld", (const char *) DUK_FILE_MACRO, (long) DUK_LINE_MACRO)); \
                duk__recursion_increase((comp_ctx)); \
        } while (0)

#define DUK__RECURSION_DECREASE(comp_ctx,thr)  do { \
                DUK_DDD(DUK_DDDPRINT("RECURSION DECREASE: %s:%ld", (const char *) DUK_FILE_MACRO, (long) DUK_LINE_MACRO)); \
                duk__recursion_decrease((comp_ctx)); \
        } while (0)

/* Value stack slot limits: these are quite approximate right now, and
 * because they overlap in control flow, some could be eliminated.
 */
#define DUK__COMPILE_ENTRY_SLOTS          8
#define DUK__FUNCTION_INIT_REQUIRE_SLOTS  16
#define DUK__FUNCTION_BODY_REQUIRE_SLOTS  16
#define DUK__PARSE_STATEMENTS_SLOTS       16
#define DUK__PARSE_EXPR_SLOTS             16

/* Temporary structure used to pass a stack allocated region through
 * duk_safe_call().
 */
typedef struct {
        duk_small_uint_t flags;
        duk_compiler_ctx comp_ctx_alloc;
        duk_lexer_point lex_pt_alloc;
} duk__compiler_stkstate;

/*
 *  Prototypes
 */

/* lexing */
DUK_LOCAL_DECL void duk__advance_helper(duk_compiler_ctx *comp_ctx, duk_small_int_t expect);
DUK_LOCAL_DECL void duk__advance_expect(duk_compiler_ctx *comp_ctx, duk_small_int_t expect);
DUK_LOCAL_DECL void duk__advance(duk_compiler_ctx *ctx);

/* function helpers */
DUK_LOCAL_DECL void duk__init_func_valstack_slots(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__reset_func_for_pass2(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__init_varmap_and_prologue_for_pass2(duk_compiler_ctx *comp_ctx, duk_reg_t *out_stmt_value_reg);
DUK_LOCAL_DECL void duk__convert_to_func_template(duk_compiler_ctx *comp_ctx, duk_bool_t force_no_namebind);
DUK_LOCAL_DECL duk_int_t duk__cleanup_varmap(duk_compiler_ctx *comp_ctx);

/* code emission */
DUK_LOCAL_DECL duk_int_t duk__get_current_pc(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL duk_compiler_instr *duk__get_instr_ptr(duk_compiler_ctx *comp_ctx, duk_int_t pc);
DUK_LOCAL_DECL void duk__emit(duk_compiler_ctx *comp_ctx, duk_instr_t ins);
#if 0  /* unused */
DUK_LOCAL_DECL void duk__emit_op_only(duk_compiler_ctx *comp_ctx, duk_small_uint_t op);
#endif
DUK_LOCAL_DECL void duk__emit_a_b_c(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t b, duk_regconst_t c);
DUK_LOCAL_DECL void duk__emit_a_b(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t b);
#if 0  /* unused */
DUK_LOCAL_DECL void duk__emit_a(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a);
#endif
DUK_LOCAL_DECL void duk__emit_a_bc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t bc);
DUK_LOCAL_DECL void duk__emit_abc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op, duk_regconst_t abc);
DUK_LOCAL_DECL void duk__emit_extraop_b_c(duk_compiler_ctx *comp_ctx, duk_small_uint_t extraop_flags, duk_regconst_t b, duk_regconst_t c);
DUK_LOCAL_DECL void duk__emit_extraop_b(duk_compiler_ctx *comp_ctx, duk_small_uint_t extraop_flags, duk_regconst_t b);
DUK_LOCAL_DECL void duk__emit_extraop_bc(duk_compiler_ctx *comp_ctx, duk_small_uint_t extraop, duk_regconst_t bc);
DUK_LOCAL_DECL void duk__emit_extraop_only(duk_compiler_ctx *comp_ctx, duk_small_uint_t extraop_flags);
DUK_LOCAL_DECL void duk__emit_load_int32(duk_compiler_ctx *comp_ctx, duk_reg_t reg, duk_int32_t val);
DUK_LOCAL_DECL void duk__emit_load_int32_noshuffle(duk_compiler_ctx *comp_ctx, duk_reg_t reg, duk_int32_t val);
DUK_LOCAL_DECL void duk__emit_jump(duk_compiler_ctx *comp_ctx, duk_int_t target_pc);
DUK_LOCAL_DECL duk_int_t duk__emit_jump_empty(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__insert_jump_entry(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc);
DUK_LOCAL_DECL void duk__patch_jump(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc, duk_int_t target_pc);
DUK_LOCAL_DECL void duk__patch_jump_here(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc);
DUK_LOCAL_DECL void duk__patch_trycatch(duk_compiler_ctx *comp_ctx, duk_int_t ldconst_pc, duk_int_t trycatch_pc, duk_regconst_t reg_catch, duk_regconst_t const_varname, duk_small_uint_t flags);
DUK_LOCAL_DECL void duk__emit_if_false_skip(duk_compiler_ctx *comp_ctx, duk_regconst_t regconst);
DUK_LOCAL_DECL void duk__emit_if_true_skip(duk_compiler_ctx *comp_ctx, duk_regconst_t regconst);
DUK_LOCAL_DECL void duk__emit_invalid(duk_compiler_ctx *comp_ctx);

/* ivalue/ispec helpers */
DUK_LOCAL_DECL void duk__copy_ispec(duk_compiler_ctx *comp_ctx, duk_ispec *src, duk_ispec *dst);
DUK_LOCAL_DECL void duk__copy_ivalue(duk_compiler_ctx *comp_ctx, duk_ivalue *src, duk_ivalue *dst);
DUK_LOCAL_DECL duk_bool_t duk__is_whole_get_int32(duk_double_t x, duk_int32_t *ival);
DUK_LOCAL_DECL duk_reg_t duk__alloctemps(duk_compiler_ctx *comp_ctx, duk_small_int_t num);
DUK_LOCAL_DECL duk_reg_t duk__alloctemp(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__settemp_checkmax(duk_compiler_ctx *comp_ctx, duk_reg_t temp_next);
DUK_LOCAL_DECL duk_regconst_t duk__getconst(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL
duk_regconst_t duk__ispec_toregconst_raw(duk_compiler_ctx *comp_ctx,
                                         duk_ispec *x,
                                         duk_reg_t forced_reg,
                                         duk_small_uint_t flags);
DUK_LOCAL_DECL void duk__ispec_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ispec *x, duk_reg_t forced_reg);
DUK_LOCAL_DECL void duk__ivalue_toplain_raw(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_reg_t forced_reg);
DUK_LOCAL_DECL void duk__ivalue_toplain(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
DUK_LOCAL_DECL void duk__ivalue_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
DUK_LOCAL_DECL
duk_regconst_t duk__ivalue_toregconst_raw(duk_compiler_ctx *comp_ctx,
                                          duk_ivalue *x,
                                          duk_reg_t forced_reg,
                                          duk_small_uint_t flags);
DUK_LOCAL_DECL duk_reg_t duk__ivalue_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
#if 0  /* unused */
DUK_LOCAL_DECL duk_reg_t duk__ivalue_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
#endif
DUK_LOCAL_DECL void duk__ivalue_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_int_t forced_reg);
DUK_LOCAL_DECL duk_regconst_t duk__ivalue_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *x);
DUK_LOCAL_DECL duk_regconst_t duk__ivalue_totempconst(duk_compiler_ctx *comp_ctx, duk_ivalue *x);

/* identifier handling */
DUK_LOCAL_DECL duk_reg_t duk__lookup_active_register_binding(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL duk_bool_t duk__lookup_lhs(duk_compiler_ctx *ctx, duk_reg_t *out_reg_varbind, duk_regconst_t *out_rc_varname);

/* label handling */
DUK_LOCAL_DECL void duk__add_label(duk_compiler_ctx *comp_ctx, duk_hstring *h_label, duk_int_t pc_label, duk_int_t label_id);
DUK_LOCAL_DECL void duk__update_label_flags(duk_compiler_ctx *comp_ctx, duk_int_t label_id, duk_small_uint_t flags);
DUK_LOCAL_DECL void duk__lookup_active_label(duk_compiler_ctx *comp_ctx, duk_hstring *h_label, duk_bool_t is_break, duk_int_t *out_label_id, duk_int_t *out_label_catch_depth, duk_int_t *out_label_pc, duk_bool_t *out_is_closest);
DUK_LOCAL_DECL void duk__reset_labels_to_length(duk_compiler_ctx *comp_ctx, duk_int_t len);

/* top-down expression parser */
DUK_LOCAL_DECL void duk__expr_nud(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__expr_led(duk_compiler_ctx *comp_ctx, duk_ivalue *left, duk_ivalue *res);
DUK_LOCAL_DECL duk_small_uint_t duk__expr_lbp(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL duk_bool_t duk__expr_is_empty(duk_compiler_ctx *comp_ctx);

/* exprtop is the top level variant which resets nud/led counts */
DUK_LOCAL_DECL void duk__expr(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
DUK_LOCAL_DECL void duk__exprtop(duk_compiler_ctx *ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);

/* convenience helpers */
#if 0  /* unused */
DUK_LOCAL_DECL duk_reg_t duk__expr_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif
#if 0  /* unused */
DUK_LOCAL_DECL duk_reg_t duk__expr_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif
DUK_LOCAL_DECL void duk__expr_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags, duk_reg_t forced_reg);
DUK_LOCAL_DECL duk_regconst_t duk__expr_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#if 0  /* unused */
DUK_LOCAL_DECL duk_regconst_t duk__expr_totempconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif
DUK_LOCAL_DECL void duk__expr_toplain(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
DUK_LOCAL_DECL void duk__expr_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
DUK_LOCAL_DECL duk_reg_t duk__exprtop_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#if 0  /* unused */
DUK_LOCAL_DECL duk_reg_t duk__exprtop_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif
DUK_LOCAL_DECL void duk__exprtop_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags, duk_reg_t forced_reg);
DUK_LOCAL_DECL duk_regconst_t duk__exprtop_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#if 0  /* unused */
DUK_LOCAL_DECL void duk__exprtop_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags);
#endif

/* expression parsing helpers */
DUK_LOCAL_DECL duk_int_t duk__parse_arguments(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__nud_array_literal(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__nud_object_literal(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL duk_bool_t duk__nud_object_literal_key_check(duk_compiler_ctx *comp_ctx, duk_small_uint_t new_key_flags);

/* statement parsing */
DUK_LOCAL_DECL void duk__parse_var_decl(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t expr_flags, duk_reg_t *out_reg_varbind, duk_regconst_t *out_rc_varname);
DUK_LOCAL_DECL void duk__parse_var_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t expr_flags);
DUK_LOCAL_DECL void duk__parse_for_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site);
DUK_LOCAL_DECL void duk__parse_switch_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site);
DUK_LOCAL_DECL void duk__parse_if_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_do_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site);
DUK_LOCAL_DECL void duk__parse_while_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site);
DUK_LOCAL_DECL void duk__parse_break_or_continue_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_return_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_throw_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_try_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_with_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res);
DUK_LOCAL_DECL void duk__parse_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_bool_t allow_source_elem);
DUK_LOCAL_DECL duk_int_t duk__stmt_label_site(duk_compiler_ctx *comp_ctx, duk_int_t label_id);
DUK_LOCAL_DECL void duk__parse_stmts(duk_compiler_ctx *comp_ctx, duk_bool_t allow_source_elem, duk_bool_t expect_eof);

DUK_LOCAL_DECL void duk__parse_func_body(duk_compiler_ctx *comp_ctx, duk_bool_t expect_eof, duk_bool_t implicit_return_value, duk_small_int_t expect_token);
DUK_LOCAL_DECL void duk__parse_func_formals(duk_compiler_ctx *comp_ctx);
DUK_LOCAL_DECL void duk__parse_func_like_raw(duk_compiler_ctx *comp_ctx, duk_bool_t is_decl, duk_bool_t is_setget);
DUK_LOCAL_DECL duk_int_t duk__parse_func_like_fnum(duk_compiler_ctx *comp_ctx, duk_bool_t is_decl, duk_bool_t is_setget);

/*
 *  Parser control values for tokens.  The token table is ordered by the
 *  DUK_TOK_XXX defines.
 *
 *  The binding powers are for lbp() use (i.e. for use in led() context).
 *  Binding powers are positive for typing convenience, and bits at the
 *  top should be reserved for flags.  Binding power step must be higher
 *  than 1 so that binding power "lbp - 1" can be used for right associative
 *  operators.  Currently a step of 2 is used (which frees one more bit for
 *  flags).
 */

/* XXX: actually single step levels would work just fine, clean up */

/* binding power "levels" (see doc/compiler.rst) */
#define DUK__BP_INVALID                0             /* always terminates led() */
#define DUK__BP_EOF                    2
#define DUK__BP_CLOSING                4             /* token closes expression, e.g. ')', ']' */
#define DUK__BP_FOR_EXPR               DUK__BP_CLOSING    /* bp to use when parsing a top level Expression */
#define DUK__BP_COMMA                  6
#define DUK__BP_ASSIGNMENT             8
#define DUK__BP_CONDITIONAL            10
#define DUK__BP_LOR                    12
#define DUK__BP_LAND                   14
#define DUK__BP_BOR                    16
#define DUK__BP_BXOR                   18
#define DUK__BP_BAND                   20
#define DUK__BP_EQUALITY               22
#define DUK__BP_RELATIONAL             24
#define DUK__BP_SHIFT                  26
#define DUK__BP_ADDITIVE               28
#define DUK__BP_MULTIPLICATIVE         30
#define DUK__BP_POSTFIX                32
#define DUK__BP_CALL                   34
#define DUK__BP_MEMBER                 36

#define DUK__TOKEN_LBP_BP_MASK         0x1f
#define DUK__TOKEN_LBP_FLAG_NO_REGEXP  (1 << 5)   /* regexp literal must not follow this token */
#define DUK__TOKEN_LBP_FLAG_TERMINATES (1 << 6)   /* terminates expression; e.g. post-increment/-decrement */
#define DUK__TOKEN_LBP_FLAG_UNUSED     (1 << 7)   /* spare */

#define DUK__TOKEN_LBP_GET_BP(x)       ((duk_small_uint_t) (((x) & DUK__TOKEN_LBP_BP_MASK) * 2))

#define DUK__MK_LBP(bp)                ((bp) >> 1)    /* bp is assumed to be even */
#define DUK__MK_LBP_FLAGS(bp,flags)    (((bp) >> 1) | (flags))

DUK_LOCAL const duk_uint8_t duk__token_lbp[] = {
        DUK__MK_LBP(DUK__BP_EOF),                                 /* DUK_TOK_EOF */
        DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_IDENTIFIER */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_BREAK */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CASE */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CATCH */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CONTINUE */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_DEBUGGER */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_DEFAULT */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_DELETE */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_DO */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_ELSE */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_FINALLY */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_FOR */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_FUNCTION */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_IF */
        DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_IN */
        DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_INSTANCEOF */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_NEW */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_RETURN */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_SWITCH */
        DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_THIS */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_THROW */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_TRY */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_TYPEOF */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_VAR */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CONST */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_VOID */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_WHILE */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_WITH */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_CLASS */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_ENUM */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_EXPORT */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_EXTENDS */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_IMPORT */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_SUPER */
        DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_NULL */
        DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_TRUE */
        DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_FALSE */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_GET */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_SET */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_IMPLEMENTS */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_INTERFACE */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_LET */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_PACKAGE */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_PRIVATE */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_PROTECTED */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_PUBLIC */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_STATIC */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_YIELD */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_LCURLY */
        DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_RCURLY */
        DUK__MK_LBP(DUK__BP_MEMBER),                              /* DUK_TOK_LBRACKET */
        DUK__MK_LBP_FLAGS(DUK__BP_CLOSING, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_RBRACKET */
        DUK__MK_LBP(DUK__BP_CALL),                                /* DUK_TOK_LPAREN */
        DUK__MK_LBP_FLAGS(DUK__BP_CLOSING, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_RPAREN */
        DUK__MK_LBP(DUK__BP_MEMBER),                              /* DUK_TOK_PERIOD */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_SEMICOLON */
        DUK__MK_LBP(DUK__BP_COMMA),                               /* DUK_TOK_COMMA */
        DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_LT */
        DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_GT */
        DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_LE */
        DUK__MK_LBP(DUK__BP_RELATIONAL),                          /* DUK_TOK_GE */
        DUK__MK_LBP(DUK__BP_EQUALITY),                            /* DUK_TOK_EQ */
        DUK__MK_LBP(DUK__BP_EQUALITY),                            /* DUK_TOK_NEQ */
        DUK__MK_LBP(DUK__BP_EQUALITY),                            /* DUK_TOK_SEQ */
        DUK__MK_LBP(DUK__BP_EQUALITY),                            /* DUK_TOK_SNEQ */
        DUK__MK_LBP(DUK__BP_ADDITIVE),                            /* DUK_TOK_ADD */
        DUK__MK_LBP(DUK__BP_ADDITIVE),                            /* DUK_TOK_SUB */
        DUK__MK_LBP(DUK__BP_MULTIPLICATIVE),                      /* DUK_TOK_MUL */
        DUK__MK_LBP(DUK__BP_MULTIPLICATIVE),                      /* DUK_TOK_DIV */
        DUK__MK_LBP(DUK__BP_MULTIPLICATIVE),                      /* DUK_TOK_MOD */
        DUK__MK_LBP(DUK__BP_POSTFIX),                             /* DUK_TOK_INCREMENT */
        DUK__MK_LBP(DUK__BP_POSTFIX),                             /* DUK_TOK_DECREMENT */
        DUK__MK_LBP(DUK__BP_SHIFT),                               /* DUK_TOK_ALSHIFT */
        DUK__MK_LBP(DUK__BP_SHIFT),                               /* DUK_TOK_ARSHIFT */
        DUK__MK_LBP(DUK__BP_SHIFT),                               /* DUK_TOK_RSHIFT */
        DUK__MK_LBP(DUK__BP_BAND),                                /* DUK_TOK_BAND */
        DUK__MK_LBP(DUK__BP_BOR),                                 /* DUK_TOK_BOR */
        DUK__MK_LBP(DUK__BP_BXOR),                                /* DUK_TOK_BXOR */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_LNOT */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_BNOT */
        DUK__MK_LBP(DUK__BP_LAND),                                /* DUK_TOK_LAND */
        DUK__MK_LBP(DUK__BP_LOR),                                 /* DUK_TOK_LOR */
        DUK__MK_LBP(DUK__BP_CONDITIONAL),                         /* DUK_TOK_QUESTION */
        DUK__MK_LBP(DUK__BP_INVALID),                             /* DUK_TOK_COLON */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_EQUALSIGN */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_ADD_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_SUB_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_MUL_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_DIV_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_MOD_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_ALSHIFT_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_ARSHIFT_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_RSHIFT_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_BAND_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_BOR_EQ */
        DUK__MK_LBP(DUK__BP_ASSIGNMENT),                          /* DUK_TOK_BXOR_EQ */
        DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_NUMBER */
        DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_STRING */
        DUK__MK_LBP_FLAGS(DUK__BP_INVALID, DUK__TOKEN_LBP_FLAG_NO_REGEXP),  /* DUK_TOK_REGEXP */
};

/*
 *  Misc helpers
 */

DUK_LOCAL void duk__recursion_increase(duk_compiler_ctx *comp_ctx) {
        DUK_ASSERT(comp_ctx != NULL);
        DUK_ASSERT(comp_ctx->recursion_depth >= 0);
        if (comp_ctx->recursion_depth >= comp_ctx->recursion_limit) {
                DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_COMPILER_RECURSION_LIMIT);
        }
        comp_ctx->recursion_depth++;
}

DUK_LOCAL void duk__recursion_decrease(duk_compiler_ctx *comp_ctx) {
        DUK_ASSERT(comp_ctx != NULL);
        DUK_ASSERT(comp_ctx->recursion_depth > 0);
        comp_ctx->recursion_depth--;
}

DUK_LOCAL duk_bool_t duk__hstring_is_eval_or_arguments(duk_compiler_ctx *comp_ctx, duk_hstring *h) {
        DUK_UNREF(comp_ctx);
        DUK_ASSERT(h != NULL);
        return DUK_HSTRING_HAS_EVAL_OR_ARGUMENTS(h);
}

DUK_LOCAL duk_bool_t duk__hstring_is_eval_or_arguments_in_strict_mode(duk_compiler_ctx *comp_ctx, duk_hstring *h) {
        DUK_ASSERT(h != NULL);
        return (comp_ctx->curr_func.is_strict &&
                DUK_HSTRING_HAS_EVAL_OR_ARGUMENTS(h));
}

/*
 *  Parser duk__advance() token eating functions
 */

/* XXX: valstack handling is awkward.  Add a valstack helper which
 * avoids dup():ing; valstack_copy(src, dst)?
 */

DUK_LOCAL void duk__advance_helper(duk_compiler_ctx *comp_ctx, duk_small_int_t expect) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_bool_t regexp;

        DUK_ASSERT(comp_ctx->curr_token.t >= 0 && comp_ctx->curr_token.t <= DUK_TOK_MAXVAL);  /* MAXVAL is inclusive */

        /*
         *  Use current token to decide whether a RegExp can follow.
         *
         *  We can use either 't' or 't_nores'; the latter would not
         *  recognize keywords.  Some keywords can be followed by a
         *  RegExp (e.g. "return"), so using 't' is better.  This is
         *  not trivial, see doc/compiler.rst.
         */

        regexp = 1;
        if (duk__token_lbp[comp_ctx->curr_token.t] & DUK__TOKEN_LBP_FLAG_NO_REGEXP) {
                regexp = 0;
        }
        if (comp_ctx->curr_func.reject_regexp_in_adv) {
                comp_ctx->curr_func.reject_regexp_in_adv = 0;
                regexp = 0;
        }

        if (expect >= 0 && comp_ctx->curr_token.t != expect) {
                DUK_D(DUK_DPRINT("parse error: expect=%ld, got=%ld",
                                 (long) expect, (long) comp_ctx->curr_token.t));
                DUK_ERROR_SYNTAX(thr, DUK_STR_PARSE_ERROR);
        }

        /* make current token the previous; need to fiddle with valstack "backing store" */
        DUK_MEMCPY(&comp_ctx->prev_token, &comp_ctx->curr_token, sizeof(duk_token));
        duk_copy(ctx, comp_ctx->tok11_idx, comp_ctx->tok21_idx);
        duk_copy(ctx, comp_ctx->tok12_idx, comp_ctx->tok22_idx);

        /* parse new token */
        duk_lexer_parse_js_input_element(&comp_ctx->lex,
                                         &comp_ctx->curr_token,
                                         comp_ctx->curr_func.is_strict,
                                         regexp);

        DUK_DDD(DUK_DDDPRINT("advance: curr: tok=%ld/%ld,%ld,term=%ld,%!T,%!T "
                             "prev: tok=%ld/%ld,%ld,term=%ld,%!T,%!T",
                             (long) comp_ctx->curr_token.t,
                             (long) comp_ctx->curr_token.t_nores,
                             (long) comp_ctx->curr_token.start_line,
                             (long) comp_ctx->curr_token.lineterm,
                             (duk_tval *) duk_get_tval(ctx, comp_ctx->tok11_idx),
                             (duk_tval *) duk_get_tval(ctx, comp_ctx->tok12_idx),
                             (long) comp_ctx->prev_token.t,
                             (long) comp_ctx->prev_token.t_nores,
                             (long) comp_ctx->prev_token.start_line,
                             (long) comp_ctx->prev_token.lineterm,
                             (duk_tval *) duk_get_tval(ctx, comp_ctx->tok21_idx),
                             (duk_tval *) duk_get_tval(ctx, comp_ctx->tok22_idx)));
}

/* advance, expecting current token to be a specific token; parse next token in regexp context */
DUK_LOCAL void duk__advance_expect(duk_compiler_ctx *comp_ctx, duk_small_int_t expect) {
        duk__advance_helper(comp_ctx, expect);
}

/* advance, whatever the current token is; parse next token in regexp context */
DUK_LOCAL void duk__advance(duk_compiler_ctx *comp_ctx) {
        duk__advance_helper(comp_ctx, -1);
}

/*
 *  Helpers for duk_compiler_func.
 */

/* init function state: inits valstack allocations */
DUK_LOCAL void duk__init_func_valstack_slots(duk_compiler_ctx *comp_ctx) {
        duk_compiler_func *func = &comp_ctx->curr_func;
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_idx_t entry_top;

        entry_top = duk_get_top(ctx);

        DUK_MEMZERO(func, sizeof(*func));  /* intentional overlap with earlier memzero */
#ifdef DUK_USE_EXPLICIT_NULL_INIT
        func->h_name = NULL;
        func->h_consts = NULL;
        func->h_funcs = NULL;
        func->h_decls = NULL;
        func->h_labelnames = NULL;
        func->h_labelinfos = NULL;
        func->h_argnames = NULL;
        func->h_varmap = NULL;
#endif

        duk_require_stack(ctx, DUK__FUNCTION_INIT_REQUIRE_SLOTS);

        DUK_BW_INIT_PUSHBUF(thr, &func->bw_code, DUK__BC_INITIAL_INSTS * sizeof(duk_compiler_instr));
        /* code_idx = entry_top + 0 */

        duk_push_array(ctx);
        func->consts_idx = entry_top + 1;
        func->h_consts = DUK_GET_HOBJECT_POSIDX(ctx, entry_top + 1);
        DUK_ASSERT(func->h_consts != NULL);

        duk_push_array(ctx);
        func->funcs_idx = entry_top + 2;
        func->h_funcs = DUK_GET_HOBJECT_POSIDX(ctx, entry_top + 2);
        DUK_ASSERT(func->h_funcs != NULL);
        DUK_ASSERT(func->fnum_next == 0);

        duk_push_array(ctx);
        func->decls_idx = entry_top + 3;
        func->h_decls = DUK_GET_HOBJECT_POSIDX(ctx, entry_top + 3);
        DUK_ASSERT(func->h_decls != NULL);

        duk_push_array(ctx);
        func->labelnames_idx = entry_top + 4;
        func->h_labelnames = DUK_GET_HOBJECT_POSIDX(ctx, entry_top + 4);
        DUK_ASSERT(func->h_labelnames != NULL);

        duk_push_dynamic_buffer(ctx, 0);
        func->labelinfos_idx = entry_top + 5;
        func->h_labelinfos = (duk_hbuffer_dynamic *) duk_get_hbuffer(ctx, entry_top + 5);
        DUK_ASSERT(func->h_labelinfos != NULL);
        DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(func->h_labelinfos) && !DUK_HBUFFER_HAS_EXTERNAL(func->h_labelinfos));

        duk_push_array(ctx);
        func->argnames_idx = entry_top + 6;
        func->h_argnames = DUK_GET_HOBJECT_POSIDX(ctx, entry_top + 6);
        DUK_ASSERT(func->h_argnames != NULL);

        duk_push_object_internal(ctx);
        func->varmap_idx = entry_top + 7;
        func->h_varmap = DUK_GET_HOBJECT_POSIDX(ctx, entry_top + 7);
        DUK_ASSERT(func->h_varmap != NULL);
}

/* reset function state (prepare for pass 2) */
DUK_LOCAL void duk__reset_func_for_pass2(duk_compiler_ctx *comp_ctx) {
        duk_compiler_func *func = &comp_ctx->curr_func;
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;

        /* reset bytecode buffer but keep current size; pass 2 will
         * require same amount or more.
         */
        DUK_BW_RESET_SIZE(thr, &func->bw_code);

        duk_hobject_set_length_zero(thr, func->h_consts);
        /* keep func->h_funcs; inner functions are not reparsed to avoid O(depth^2) parsing */
        func->fnum_next = 0;
        /* duk_hobject_set_length_zero(thr, func->h_funcs); */
        duk_hobject_set_length_zero(thr, func->h_labelnames);
        duk_hbuffer_reset(thr, func->h_labelinfos);
        /* keep func->h_argnames; it is fixed for all passes */

        /* truncated in case pass 3 needed */
        duk_push_object_internal(ctx);
        duk_replace(ctx, func->varmap_idx);
        func->h_varmap = DUK_GET_HOBJECT_POSIDX(ctx, func->varmap_idx);
        DUK_ASSERT(func->h_varmap != NULL);
}

/* cleanup varmap from any null entries, compact it, etc; returns number
 * of final entries after cleanup.
 */
DUK_LOCAL duk_int_t duk__cleanup_varmap(duk_compiler_ctx *comp_ctx) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_hobject *h_varmap;
        duk_hstring *h_key;
        duk_tval *tv;
        duk_uint32_t i, e_next;
        duk_int_t ret;

        /* [ ... varmap ] */

        h_varmap = DUK_GET_HOBJECT_NEGIDX(ctx, -1);
        DUK_ASSERT(h_varmap != NULL);

        ret = 0;
        e_next = DUK_HOBJECT_GET_ENEXT(h_varmap);
        for (i = 0; i < e_next; i++) {
                h_key = DUK_HOBJECT_E_GET_KEY(thr->heap, h_varmap, i);
                if (!h_key) {
                        continue;
                }

                DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, h_varmap, i));

                /* The entries can either be register numbers or 'null' values.
                 * Thus, no need to DECREF them and get side effects.  DECREF'ing
                 * the keys (strings) can cause memory to be freed but no side
                 * effects as strings don't have finalizers.  This is why we can
                 * rely on the object properties not changing from underneath us.
                 */

                tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, h_varmap, i);
                if (!DUK_TVAL_IS_NUMBER(tv)) {
                        DUK_ASSERT(!DUK_TVAL_IS_HEAP_ALLOCATED(tv));
                        DUK_HOBJECT_E_SET_KEY(thr->heap, h_varmap, i, NULL);
                        DUK_HSTRING_DECREF(thr, h_key);
                        /* when key is NULL, value is garbage so no need to set */
                } else {
                        ret++;
                }
        }

        duk_compact(ctx, -1);

        return ret;
}

/* convert duk_compiler_func into a function template, leaving the result
 * on top of stack.
 */
/* XXX: awkward and bloated asm -- use faster internal accesses */
DUK_LOCAL void duk__convert_to_func_template(duk_compiler_ctx *comp_ctx, duk_bool_t force_no_namebind) {
        duk_compiler_func *func = &comp_ctx->curr_func;
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_hcompiledfunction *h_res;
        duk_hbuffer_fixed *h_data;
        duk_size_t consts_count;
        duk_size_t funcs_count;
        duk_size_t code_count;
        duk_size_t code_size;
        duk_size_t data_size;
        duk_size_t i;
        duk_tval *p_const;
        duk_hobject **p_func;
        duk_instr_t *p_instr;
        duk_compiler_instr *q_instr;
        duk_tval *tv;

        DUK_DDD(DUK_DDDPRINT("converting duk_compiler_func to function/template"));

        /*
         *  Push result object and init its flags
         */

        /* Valstack should suffice here, required on function valstack init */

        (void) duk_push_compiledfunction(ctx);
        h_res = (duk_hcompiledfunction *) DUK_GET_HOBJECT_NEGIDX(ctx, -1);  /* XXX: specific getter */
        DUK_ASSERT(h_res != NULL);

        if (func->is_function) {
                DUK_DDD(DUK_DDDPRINT("function -> set NEWENV"));
                DUK_HOBJECT_SET_NEWENV((duk_hobject *) h_res);

                if (!func->is_arguments_shadowed) {
                        /* arguments object would be accessible; note that shadowing
                         * bindings are arguments or function declarations, neither
                         * of which are deletable, so this is safe.
                         */

                        if (func->id_access_arguments || func->may_direct_eval) {
                                DUK_DDD(DUK_DDDPRINT("function may access 'arguments' object directly or "
                                                     "indirectly -> set CREATEARGS"));
                                DUK_HOBJECT_SET_CREATEARGS((duk_hobject *) h_res);
                        }
                }
        } else if (func->is_eval && func->is_strict) {
                DUK_DDD(DUK_DDDPRINT("strict eval code -> set NEWENV"));
                DUK_HOBJECT_SET_NEWENV((duk_hobject *) h_res);
        } else {
                /* non-strict eval: env is caller's env or global env (direct vs. indirect call)
                 * global code: env is is global env
                 */
                DUK_DDD(DUK_DDDPRINT("non-strict eval code or global code -> no NEWENV"));
                DUK_ASSERT(!DUK_HOBJECT_HAS_NEWENV((duk_hobject *) h_res));
        }

        if (func->is_function && !func->is_decl && func->h_name != NULL && !force_no_namebind) {
                /* Object literal set/get functions have a name (property
                 * name) but must not have a lexical name binding, see
                 * test-bug-getset-func-name.js.
                 */
                DUK_DDD(DUK_DDDPRINT("function expression with a name -> set NAMEBINDING"));
                DUK_HOBJECT_SET_NAMEBINDING((duk_hobject *) h_res);
        }

        if (func->is_strict) {
                DUK_DDD(DUK_DDDPRINT("function is strict -> set STRICT"));
                DUK_HOBJECT_SET_STRICT((duk_hobject *) h_res);
        }

        if (func->is_notail) {
                DUK_DDD(DUK_DDDPRINT("function is notail -> set NOTAIL"));
                DUK_HOBJECT_SET_NOTAIL((duk_hobject *) h_res);
        }

        /*
         *  Build function fixed size 'data' buffer, which contains bytecode,
         *  constants, and inner function references.
         *
         *  During the building phase 'data' is reachable but incomplete.
         *  Only incref's occur during building (no refzero or GC happens),
         *  so the building process is atomic.
         */

        consts_count = duk_hobject_get_length(thr, func->h_consts);
        funcs_count = duk_hobject_get_length(thr, func->h_funcs) / 3;
        code_count = DUK_BW_GET_SIZE(thr, &func->bw_code) / sizeof(duk_compiler_instr);
        code_size = code_count * sizeof(duk_instr_t);

        data_size = consts_count * sizeof(duk_tval) +
                    funcs_count * sizeof(duk_hobject *) +
                    code_size;

        DUK_DDD(DUK_DDDPRINT("consts_count=%ld, funcs_count=%ld, code_size=%ld -> "
                             "data_size=%ld*%ld + %ld*%ld + %ld = %ld",
                             (long) consts_count, (long) funcs_count, (long) code_size,
                             (long) consts_count, (long) sizeof(duk_tval),
                             (long) funcs_count, (long) sizeof(duk_hobject *),
                             (long) code_size, (long) data_size));

        duk_push_fixed_buffer(ctx, data_size);
        h_data = (duk_hbuffer_fixed *) duk_get_hbuffer(ctx, -1);
        DUK_ASSERT(h_data != NULL);

        DUK_HCOMPILEDFUNCTION_SET_DATA(thr->heap, h_res, (duk_hbuffer *) h_data);
        DUK_HEAPHDR_INCREF(thr, h_data);

        p_const = (duk_tval *) (void *) DUK_HBUFFER_FIXED_GET_DATA_PTR(thr->heap, h_data);
        for (i = 0; i < consts_count; i++) {
                DUK_ASSERT(i <= DUK_UARRIDX_MAX);  /* const limits */
                tv = duk_hobject_find_existing_array_entry_tval_ptr(thr->heap, func->h_consts, (duk_uarridx_t) i);
                DUK_ASSERT(tv != NULL);
                DUK_TVAL_SET_TVAL(p_const, tv);
                p_const++;
                DUK_TVAL_INCREF(thr, tv);  /* may be a string constant */

                DUK_DDD(DUK_DDDPRINT("constant: %!T", (duk_tval *) tv));
        }

        p_func = (duk_hobject **) p_const;
        DUK_HCOMPILEDFUNCTION_SET_FUNCS(thr->heap, h_res, p_func);
        for (i = 0; i < funcs_count; i++) {
                duk_hobject *h;
                DUK_ASSERT(i * 3 <= DUK_UARRIDX_MAX);  /* func limits */
                tv = duk_hobject_find_existing_array_entry_tval_ptr(thr->heap, func->h_funcs, (duk_uarridx_t) (i * 3));
                DUK_ASSERT(tv != NULL);
                DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv));
                h = DUK_TVAL_GET_OBJECT(tv);
                DUK_ASSERT(h != NULL);
                DUK_ASSERT(DUK_HOBJECT_IS_COMPILEDFUNCTION(h));
                *p_func++ = h;
                DUK_HOBJECT_INCREF(thr, h);

                DUK_DDD(DUK_DDDPRINT("inner function: %p -> %!iO",
                                     (void *) h, (duk_heaphdr *) h));
        }

        p_instr = (duk_instr_t *) p_func;
        DUK_HCOMPILEDFUNCTION_SET_BYTECODE(thr->heap, h_res, p_instr);

        /* copy bytecode instructions one at a time */
        q_instr = (duk_compiler_instr *) (void *) DUK_BW_GET_BASEPTR(thr, &func->bw_code);
        for (i = 0; i < code_count; i++) {
                p_instr[i] = q_instr[i].ins;
        }
        /* Note: 'q_instr' is still used below */

        DUK_ASSERT((duk_uint8_t *) (p_instr + code_count) == DUK_HBUFFER_FIXED_GET_DATA_PTR(thr->heap, h_data) + data_size);

        duk_pop(ctx);  /* 'data' (and everything in it) is reachable through h_res now */

        /*
         *  Init object properties
         *
         *  Properties should be added in decreasing order of access frequency.
         *  (Not very critical for function templates.)
         */

        DUK_DDD(DUK_DDDPRINT("init function properties"));

        /* [ ... res ] */

        /* _Varmap: omitted if function is guaranteed not to do slow path identifier
         * accesses or if it would turn out to be empty of actual register mappings
         * after a cleanup.  When debugging is enabled, we always need the varmap to
         * be able to lookup variables at any point.
         */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
        if (1) {
#else
        if (func->id_access_slow ||     /* directly uses slow accesses */
            func->may_direct_eval ||    /* may indirectly slow access through a direct eval */
            funcs_count > 0) {          /* has inner functions which may slow access (XXX: this can be optimized by looking at the inner functions) */
#endif
                duk_int_t num_used;
                duk_dup(ctx, func->varmap_idx);
                num_used = duk__cleanup_varmap(comp_ctx);
                DUK_DDD(DUK_DDDPRINT("cleaned up varmap: %!T (num_used=%ld)",
                                     (duk_tval *) duk_get_tval(ctx, -1), (long) num_used));

                if (num_used > 0) {
                        duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_VARMAP, DUK_PROPDESC_FLAGS_NONE);
                } else {
                        DUK_DDD(DUK_DDDPRINT("varmap is empty after cleanup -> no need to add"));
                        duk_pop(ctx);
                }
        }

        /* _Formals: omitted if function is guaranteed not to need a (non-strict) arguments object */
        if (1) {
                /* XXX: Add a proper condition.  If formals list is omitted, recheck
                 * handling for 'length' in duk_js_push_closure(); it currently relies
                 * on _Formals being set.  Removal may need to be conditional to debugging
                 * being enabled/disabled too.
                 */
                duk_dup(ctx, func->argnames_idx);
                duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_FORMALS, DUK_PROPDESC_FLAGS_NONE);
        }

        /* name */
        if (func->h_name) {
                duk_push_hstring(ctx, func->h_name);
                duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_NONE);
        }

        /* _Source */
#if defined(DUK_USE_NONSTD_FUNC_SOURCE_PROPERTY)
        if (0) {
                /* XXX: Currently function source code is not stored, as it is not
                 * required by the standard.  Source code should not be stored by
                 * default (user should enable it explicitly), and the source should
                 * probably be compressed with a trivial text compressor; average
                 * compression of 20-30% is quite easy to achieve even with a trivial
                 * compressor (RLE + backwards lookup).
                 *
                 * Debugging needs source code to be useful: sometimes input code is
                 * not found in files as it may be generated and then eval()'d, given
                 * by dynamic C code, etc.
                 *
                 * Other issues:
                 *
                 *   - Need tokenizer indices for start and end to substring
                 *   - Always normalize function declaration part?
                 *   - If we keep _Formals, only need to store body
                 */

                /*
                 *  For global or eval code this is straightforward.  For functions
                 *  created with the Function constructor we only get the source for
                 *  the body and must manufacture the "function ..." part.
                 *
                 *  For instance, for constructed functions (v8):
                 *
                 *    > a = new Function("foo", "bar", "print(foo)");
                 *    [Function]
                 *    > a.toString()
                 *    'function anonymous(foo,bar) {\nprint(foo)\n}'
                 *
                 *  Similarly for e.g. getters (v8):
                 *
                 *    > x = { get a(foo,bar) { print(foo); } }
                 *    { a: [Getter] }
                 *    > Object.getOwnPropertyDescriptor(x, 'a').get.toString()
                 *    'function a(foo,bar) { print(foo); }'
                 */

#if 0
                duk_push_string(ctx, "XXX");
                duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_SOURCE, DUK_PROPDESC_FLAGS_NONE);
#endif
        }
#endif  /* DUK_USE_NONSTD_FUNC_SOURCE_PROPERTY */

        /* _Pc2line */
#if defined(DUK_USE_PC2LINE)
        if (1) {
                /*
                 *  Size-optimized pc->line mapping.
                 */

                DUK_ASSERT(code_count <= DUK_COMPILER_MAX_BYTECODE_LENGTH);
                duk_hobject_pc2line_pack(thr, q_instr, (duk_uint_fast32_t) code_count);  /* -> pushes fixed buffer */
                duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_PC2LINE, DUK_PROPDESC_FLAGS_NONE);

                /* XXX: if assertions enabled, walk through all valid PCs
                 * and check line mapping.
                 */
        }
#endif  /* DUK_USE_PC2LINE */

        /* fileName */
        if (comp_ctx->h_filename) {
                /*
                 *  Source filename (or equivalent), for identifying thrown errors.
                 */

                duk_push_hstring(ctx, comp_ctx->h_filename);
                duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_FILE_NAME, DUK_PROPDESC_FLAGS_NONE);
        }

        /*
         *  Init remaining result fields
         *
         *  'nregs' controls how large a register frame is allocated.
         *
         *  'nargs' controls how many formal arguments are written to registers:
         *  r0, ... r(nargs-1).  The remaining registers are initialized to
         *  undefined.
         */

        DUK_ASSERT(func->temp_max >= 0);
        h_res->nregs = (duk_uint16_t) func->temp_max;
        h_res->nargs = (duk_uint16_t) duk_hobject_get_length(thr, func->h_argnames);
        DUK_ASSERT(h_res->nregs >= h_res->nargs);  /* pass2 allocation handles this */
#if defined(DUK_USE_DEBUGGER_SUPPORT)
        h_res->start_line = (duk_uint32_t) func->min_line;
        h_res->end_line = (duk_uint32_t) func->max_line;
#endif

        DUK_DD(DUK_DDPRINT("converted function: %!ixT",
                           (duk_tval *) duk_get_tval(ctx, -1)));

        /*
         *  Compact the function template.
         */

        duk_compact(ctx, -1);

        /*
         *  Debug dumping
         */

#ifdef DUK_USE_DDDPRINT
        {
                duk_hcompiledfunction *h;
                duk_instr_t *p, *p_start, *p_end;

                h = (duk_hcompiledfunction *) duk_get_hobject(ctx, -1);
                p_start = (duk_instr_t *) DUK_HCOMPILEDFUNCTION_GET_CODE_BASE(thr->heap, h);
                p_end = (duk_instr_t *) DUK_HCOMPILEDFUNCTION_GET_CODE_END(thr->heap, h);

                p = p_start;
                while (p < p_end) {
                        DUK_DDD(DUK_DDDPRINT("BC %04ld: %!I        ; 0x%08lx op=%ld (%!C) a=%ld b=%ld c=%ld",
                                             (long) (p - p_start),
                                             (duk_instr_t) (*p),
                                             (unsigned long) (*p),
                                             (long) DUK_DEC_OP(*p),
                                             (long) DUK_DEC_OP(*p),
                                             (long) DUK_DEC_A(*p),
                                             (long) DUK_DEC_B(*p),
                                             (long) DUK_DEC_C(*p)));
                        p++;
                }
        }
#endif
}

/*
 *  Code emission helpers
 *
 *  Some emission helpers understand the range of target and source reg/const
 *  values and automatically emit shuffling code if necessary.  This is the
 *  case when the slot in question (A, B, C) is used in the standard way and
 *  for opcodes the emission helpers explicitly understand (like DUK_OP_CALL).
 *
 *  The standard way is that:
 *    - slot A is a target register
 *    - slot B is a source register/constant
 *    - slot C is a source register/constant
 *
 *  If a slot is used in a non-standard way the caller must indicate this
 *  somehow.  If a slot is used as a target instead of a source (or vice
 *  versa), this can be indicated with a flag to trigger proper shuffling
 *  (e.g. DUK__EMIT_FLAG_B_IS_TARGET).  If the value in the slot is not
 *  register/const related at all, the caller must ensure that the raw value
 *  fits into the corresponding slot so as to not trigger shuffling.  The
 *  caller must set a "no shuffle" flag to ensure compilation fails if
 *  shuffling were to be triggered because of an internal error.
 *
 *  For slots B and C the raw slot size is 9 bits but one bit is reserved for
 *  the reg/const indicator.  To use the full 9-bit range for a raw value,
 *  shuffling must be disabled with the DUK__EMIT_FLAG_NO_SHUFFLE_{B,C} flag.
 *  Shuffling is only done for A, B, and C slots, not the larger BC or ABC slots.
 *
 *  There is call handling specific understanding in the A-B-C emitter to
 *  convert call setup and call instructions into indirect ones if necessary.
 */

/* Code emission flags, passed in the 'opcode' field.  Opcode + flags
 * fit into 16 bits for now, so use duk_small_uint.t.
 */
#define DUK__EMIT_FLAG_NO_SHUFFLE_A      (1 << 8)
#define DUK__EMIT_FLAG_NO_SHUFFLE_B      (1 << 9)
#define DUK__EMIT_FLAG_NO_SHUFFLE_C      (1 << 10)
#define DUK__EMIT_FLAG_A_IS_SOURCE       (1 << 11)  /* slot A is a source (default: target) */
#define DUK__EMIT_FLAG_B_IS_TARGET       (1 << 12)  /* slot B is a target (default: source) */
#define DUK__EMIT_FLAG_C_IS_TARGET       (1 << 13)  /* slot C is a target (default: source) */
#define DUK__EMIT_FLAG_B_IS_TARGETSOURCE (1 << 14)  /* slot B is both a target and a source (used by extraops like DUK_EXTRAOP_INSTOF */
#define DUK__EMIT_FLAG_RESERVE_JUMPSLOT  (1 << 15)  /* reserve a jumpslot after instr before target spilling, used for NEXTENUM */

/* XXX: clarify on when and where DUK__CONST_MARKER is allowed */
/* XXX: opcode specific assertions on when consts are allowed */

/* XXX: macro smaller than call? */
DUK_LOCAL duk_int_t duk__get_current_pc(duk_compiler_ctx *comp_ctx) {
        duk_compiler_func *func;
        func = &comp_ctx->curr_func;
        return (duk_int_t) (DUK_BW_GET_SIZE(comp_ctx->thr, &func->bw_code) / sizeof(duk_compiler_instr));
}

DUK_LOCAL duk_compiler_instr *duk__get_instr_ptr(duk_compiler_ctx *comp_ctx, duk_int_t pc) {
        DUK_ASSERT(pc >= 0);
        DUK_ASSERT((duk_size_t) pc < (duk_size_t) (DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) / sizeof(duk_compiler_instr)));
        return ((duk_compiler_instr *) (void *) DUK_BW_GET_BASEPTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code)) + pc;
}

/* emit instruction; could return PC but that's not needed in the majority
 * of cases.
 */
DUK_LOCAL void duk__emit(duk_compiler_ctx *comp_ctx, duk_instr_t ins) {
#if defined(DUK_USE_PC2LINE)
        duk_int_t line;
#endif
        duk_compiler_instr *instr;

        DUK_DDD(DUK_DDDPRINT("duk__emit: 0x%08lx curr_token.start_line=%ld prev_token.start_line=%ld pc=%ld --> %!I",
                             (unsigned long) ins,
                             (long) comp_ctx->curr_token.start_line,
                             (long) comp_ctx->prev_token.start_line,
                             (long) duk__get_current_pc(comp_ctx),
                             (duk_instr_t) ins));

        instr = (duk_compiler_instr *) (void *) DUK_BW_ENSURE_GETPTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code, sizeof(duk_compiler_instr));
        DUK_BW_ADD_PTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code, sizeof(duk_compiler_instr));

#if defined(DUK_USE_PC2LINE)
        /* The line number tracking is a bit inconsistent right now, which
         * affects debugger accuracy.  Mostly call sites emit opcodes when
         * they have parsed a token (say a terminating semicolon) and called
         * duk__advance().  In this case the line number of the previous
         * token is the most accurate one (except in prologue where
         * prev_token.start_line is 0).  This is probably not 100% correct
         * right now.
         */
        /* approximation, close enough */
        line = comp_ctx->prev_token.start_line;
        if (line == 0) {
                line = comp_ctx->curr_token.start_line;
        }
#endif

        instr->ins = ins;
#if defined(DUK_USE_PC2LINE)
        instr->line = line;
#endif
#if defined(DUK_USE_DEBUGGER_SUPPORT)
        if (line < comp_ctx->curr_func.min_line) {
                comp_ctx->curr_func.min_line = line;
        }
        if (line > comp_ctx->curr_func.max_line) {
                comp_ctx->curr_func.max_line = line;
        }
#endif

        /* Limit checks for bytecode byte size and line number. */
        if (DUK_UNLIKELY(DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) > DUK_USE_ESBC_MAX_BYTES)) {
                goto fail_bc_limit;
        }
#if defined(DUK_USE_PC2LINE) && defined(DUK_USE_ESBC_LIMITS)
#if defined(DUK_USE_BUFLEN16)
        /* Buffer length is bounded to 0xffff automatically, avoid compile warning. */
        if (DUK_UNLIKELY(line > DUK_USE_ESBC_MAX_LINENUMBER)) {
                goto fail_bc_limit;
        }
#else
        if (DUK_UNLIKELY(line > DUK_USE_ESBC_MAX_LINENUMBER)) {
                goto fail_bc_limit;
        }
#endif
#endif

        return;

  fail_bc_limit:
        DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_BYTECODE_LIMIT);
}

/* Update function min/max line from current token.  Needed to improve
 * function line range information for debugging, so that e.g. opening
 * curly brace is covered by line range even when no opcodes are emitted
 * for the line containing the brace.
 */
DUK_LOCAL void duk__update_lineinfo_currtoken(duk_compiler_ctx *comp_ctx) {
#if defined(DUK_USE_DEBUGGER_SUPPORT)
        duk_int_t line;

        line = comp_ctx->curr_token.start_line;
        if (line == 0) {
                return;
        }
        if (line < comp_ctx->curr_func.min_line) {
                comp_ctx->curr_func.min_line = line;
        }
        if (line > comp_ctx->curr_func.max_line) {
                comp_ctx->curr_func.max_line = line;
        }
#else
        DUK_UNREF(comp_ctx);
#endif
}

#if 0 /* unused */
DUK_LOCAL void duk__emit_op_only(duk_compiler_ctx *comp_ctx, duk_small_uint_t op) {
        duk__emit(comp_ctx, DUK_ENC_OP_ABC(op, 0));
}
#endif

/* Important main primitive. */
DUK_LOCAL void duk__emit_a_b_c(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t b, duk_regconst_t c) {
        duk_instr_t ins = 0;
        duk_int_t a_out = -1;
        duk_int_t b_out = -1;
        duk_int_t c_out = -1;
        duk_int_t tmp;

        DUK_DDD(DUK_DDDPRINT("emit: op_flags=%04lx, a=%ld, b=%ld, c=%ld",
                             (unsigned long) op_flags, (long) a, (long) b, (long) c));

        /* We could rely on max temp/const checks: if they don't exceed BC
         * limit, nothing here can either (just asserts would be enough).
         * Currently we check for the limits, which provides additional
         * protection against creating invalid bytecode due to compiler
         * bugs.
         */

        DUK_ASSERT_DISABLE((op_flags & 0xff) >= DUK_BC_OP_MIN);  /* unsigned */
        DUK_ASSERT((op_flags & 0xff) <= DUK_BC_OP_MAX);

        /* Input shuffling happens before the actual operation, while output
         * shuffling happens afterwards.  Output shuffling decisions are still
         * made at the same time to reduce branch clutter; output shuffle decisions
         * are recorded into X_out variables.
         */

        /* Slot A */

#if defined(DUK_USE_SHUFFLE_TORTURE)
        if (a <= DUK_BC_A_MAX && (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_A)) {
#else
        if (a <= DUK_BC_A_MAX) {
#endif
                ;
        } else if (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_A) {
                DUK_D(DUK_DPRINT("out of regs: 'a' (reg) needs shuffling but shuffle prohibited, a: %ld", (long) a));
                goto error_outofregs;
        } else if (a <= DUK_BC_BC_MAX) {
                comp_ctx->curr_func.needs_shuffle = 1;
                tmp = comp_ctx->curr_func.shuffle1;
                if (op_flags & DUK__EMIT_FLAG_A_IS_SOURCE) {
                        duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDREG, tmp, a));
                } else {
                        duk_small_int_t op = op_flags & 0xff;
                        if (op == DUK_OP_CSVAR || op == DUK_OP_CSREG || op == DUK_OP_CSPROP) {
                                /* Special handling for call setup instructions.  The target
                                 * is expressed indirectly, but there is no output shuffling.
                                 */
                                DUK_ASSERT((op_flags & DUK__EMIT_FLAG_A_IS_SOURCE) == 0);
                                duk__emit_load_int32_noshuffle(comp_ctx, tmp, a);
                                DUK_ASSERT(DUK_OP_CSVARI == DUK_OP_CSVAR + 1);
                                DUK_ASSERT(DUK_OP_CSREGI == DUK_OP_CSREG + 1);
                                DUK_ASSERT(DUK_OP_CSPROPI == DUK_OP_CSPROP + 1);
                                op_flags++;  /* indirect opcode follows direct */
                        } else {
                                /* Output shuffle needed after main operation */
                                a_out = a;
                        }
                }
                a = tmp;
        } else {
                DUK_D(DUK_DPRINT("out of regs: 'a' (reg) needs shuffling but does not fit into BC, a: %ld", (long) a));
                goto error_outofregs;
        }

        /* Slot B */

        if (b & DUK__CONST_MARKER) {
                DUK_ASSERT((op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_B) == 0);
                DUK_ASSERT((op_flags & DUK__EMIT_FLAG_B_IS_TARGET) == 0);
                DUK_ASSERT((op_flags & 0xff) != DUK_OP_CALL);
                DUK_ASSERT((op_flags & 0xff) != DUK_OP_NEW);
                b = b & ~DUK__CONST_MARKER;
#if defined(DUK_USE_SHUFFLE_TORTURE)
                if (0) {
#else
                if (b <= 0xff) {
#endif
                        ins |= DUK_ENC_OP_A_B_C(0, 0, 0x100, 0);  /* const flag for B */
                } else if (b <= DUK_BC_BC_MAX) {
                        comp_ctx->curr_func.needs_shuffle = 1;
                        tmp = comp_ctx->curr_func.shuffle2;
                        duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDCONST, tmp, b));
                        b = tmp;
                } else {
                        DUK_D(DUK_DPRINT("out of regs: 'b' (const) needs shuffling but does not fit into BC, b: %ld", (long) b));
                        goto error_outofregs;
                }
        } else {
#if defined(DUK_USE_SHUFFLE_TORTURE)
                if (b <= 0xff && (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_B)) {
#else
                if (b <= 0xff) {
#endif
                        ;
                } else if (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_B) {
                        if (b > DUK_BC_B_MAX) {
                                /* Note: 0xff != DUK_BC_B_MAX */
                                DUK_D(DUK_DPRINT("out of regs: 'b' (reg) needs shuffling but shuffle prohibited, b: %ld", (long) b));
                                goto error_outofregs;
                        }
                } else if (b <= DUK_BC_BC_MAX) {
                        comp_ctx->curr_func.needs_shuffle = 1;
                        tmp = comp_ctx->curr_func.shuffle2;
                        if (op_flags & DUK__EMIT_FLAG_B_IS_TARGET) {
                                /* Output shuffle needed after main operation */
                                b_out = b;
                        }
                        if (!(op_flags & DUK__EMIT_FLAG_B_IS_TARGET) || (op_flags & DUK__EMIT_FLAG_B_IS_TARGETSOURCE)) {
                                duk_small_int_t op = op_flags & 0xff;
                                if (op == DUK_OP_CALL || op == DUK_OP_NEW ||
                                    op == DUK_OP_MPUTOBJ || op == DUK_OP_MPUTARR) {
                                        /* Special handling for CALL/NEW/MPUTOBJ/MPUTARR shuffling.
                                         * For each, slot B identifies the first register of a range
                                         * of registers, so normal shuffling won't work.  Instead,
                                         * an indirect version of the opcode is used.
                                         */
                                        DUK_ASSERT((op_flags & DUK__EMIT_FLAG_B_IS_TARGET) == 0);
                                        duk__emit_load_int32_noshuffle(comp_ctx, tmp, b);
                                        DUK_ASSERT(DUK_OP_CALLI == DUK_OP_CALL + 1);
                                        DUK_ASSERT(DUK_OP_NEWI == DUK_OP_NEW + 1);
                                        DUK_ASSERT(DUK_OP_MPUTOBJI == DUK_OP_MPUTOBJ + 1);
                                        DUK_ASSERT(DUK_OP_MPUTARRI == DUK_OP_MPUTARR + 1);
                                        op_flags++;  /* indirect opcode follows direct */
                                } else {
                                        duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDREG, tmp, b));
                                }
                        }
                        b = tmp;
                } else {
                        DUK_D(DUK_DPRINT("out of regs: 'b' (reg) needs shuffling but does not fit into BC, b: %ld", (long) b));
                        goto error_outofregs;
                }
        }

        /* Slot C */

        if (c & DUK__CONST_MARKER) {
                DUK_ASSERT((op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_C) == 0);
                DUK_ASSERT((op_flags & DUK__EMIT_FLAG_C_IS_TARGET) == 0);
                c = c & ~DUK__CONST_MARKER;
#if defined(DUK_USE_SHUFFLE_TORTURE)
                if (0) {
#else
                if (c <= 0xff) {
#endif
                        ins |= DUK_ENC_OP_A_B_C(0, 0, 0, 0x100);  /* const flag for C */
                } else if (c <= DUK_BC_BC_MAX) {
                        comp_ctx->curr_func.needs_shuffle = 1;
                        tmp = comp_ctx->curr_func.shuffle3;
                        duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDCONST, tmp, c));
                        c = tmp;
                } else {
                        DUK_D(DUK_DPRINT("out of regs: 'c' (const) needs shuffling but does not fit into BC, c: %ld", (long) c));
                        goto error_outofregs;
                }
        } else {
#if defined(DUK_USE_SHUFFLE_TORTURE)
                if (c <= 0xff && (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_C)) {
#else
                if (c <= 0xff) {
#endif
                        ;
                } else if (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_C) {
                        if (c > DUK_BC_C_MAX) {
                                /* Note: 0xff != DUK_BC_C_MAX */
                                DUK_D(DUK_DPRINT("out of regs: 'c' (reg) needs shuffling but shuffle prohibited, c: %ld", (long) c));
                                goto error_outofregs;
                        }
                } else if (c <= DUK_BC_BC_MAX) {
                        comp_ctx->curr_func.needs_shuffle = 1;
                        tmp = comp_ctx->curr_func.shuffle3;
                        if (op_flags & DUK__EMIT_FLAG_C_IS_TARGET) {
                                /* Output shuffle needed after main operation */
                                c_out = c;
                        } else {
                                duk_small_int_t op = op_flags & 0xff;
                                if (op == DUK_OP_EXTRA &&
                                    (a == DUK_EXTRAOP_INITGET || a == DUK_EXTRAOP_INITSET)) {
                                        /* Special shuffling for INITGET/INITSET, where slot C
                                         * identifies a register pair and cannot be shuffled
                                         * normally.  Use an indirect variant instead.
                                         */
                                        DUK_ASSERT((op_flags & DUK__EMIT_FLAG_C_IS_TARGET) == 0);
                                        duk__emit_load_int32_noshuffle(comp_ctx, tmp, c);
                                        DUK_ASSERT(DUK_EXTRAOP_INITGETI == DUK_EXTRAOP_INITGET + 1);
                                        DUK_ASSERT(DUK_EXTRAOP_INITSETI == DUK_EXTRAOP_INITSET + 1);
                                        a++;  /* indirect opcode follows direct */
                                } else {
                                        duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDREG, tmp, c));
                                }
                        }
                        c = tmp;
                } else {
                        DUK_D(DUK_DPRINT("out of regs: 'c' (reg) needs shuffling but does not fit into BC, c: %ld", (long) c));
                        goto error_outofregs;
                }
        }

        /* Main operation */

        DUK_ASSERT_DISABLE(a >= DUK_BC_A_MIN);  /* unsigned */
        DUK_ASSERT(a <= DUK_BC_A_MAX);
        DUK_ASSERT_DISABLE(b >= DUK_BC_B_MIN);  /* unsigned */
        DUK_ASSERT(b <= DUK_BC_B_MAX);
        DUK_ASSERT_DISABLE(c >= DUK_BC_C_MIN);  /* unsigned */
        DUK_ASSERT(c <= DUK_BC_C_MAX);

        ins |= DUK_ENC_OP_A_B_C(op_flags & 0xff, a, b, c);
        duk__emit(comp_ctx, ins);

        /* NEXTENUM needs a jump slot right after the main instruction.
         * When the JUMP is taken, output spilling is not needed so this
         * workaround is possible.  The jump slot PC is exceptionally
         * plumbed through comp_ctx to minimize call sites.
         */
        if (op_flags & DUK__EMIT_FLAG_RESERVE_JUMPSLOT) {
                comp_ctx->emit_jumpslot_pc = duk__get_current_pc(comp_ctx);
                duk__emit_abc(comp_ctx, DUK_OP_JUMP, 0);
        }

        /* Output shuffling: only one output register is realistically possible.
         *
         * (Zero would normally be an OK marker value: if the target register
         * was zero, it would never be shuffled.  But with DUK_USE_SHUFFLE_TORTURE
         * this is no longer true, so use -1 as a marker instead.)
         */

        if (a_out >= 0) {
                DUK_ASSERT(b_out < 0);
                DUK_ASSERT(c_out < 0);
                duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_STREG, a, a_out));
        } else if (b_out >= 0) {
                DUK_ASSERT(a_out < 0);
                DUK_ASSERT(c_out < 0);
                duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_STREG, b, b_out));
        } else if (c_out >= 0) {
                DUK_ASSERT(b_out < 0);
                DUK_ASSERT(c_out < 0);
                duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_STREG, c, c_out));
        }

        return;

 error_outofregs:
        DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_REG_LIMIT);
}

DUK_LOCAL void duk__emit_a_b(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t b) {
        duk__emit_a_b_c(comp_ctx, op_flags | DUK__EMIT_FLAG_NO_SHUFFLE_C, a, b, 0);
}

#if 0  /* unused */
DUK_LOCAL void duk__emit_a(duk_compiler_ctx *comp_ctx, int op_flags, int a) {
        duk__emit_a_b_c(comp_ctx, op_flags | DUK__EMIT_FLAG_NO_SHUFFLE_B | DUK__EMIT_FLAG_NO_SHUFFLE_C, a, 0, 0);
}
#endif

DUK_LOCAL void duk__emit_a_bc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op_flags, duk_regconst_t a, duk_regconst_t bc) {
        duk_instr_t ins;
        duk_int_t tmp;

        /* allow caller to give a const number with the DUK__CONST_MARKER */
        bc = bc & (~DUK__CONST_MARKER);

        DUK_ASSERT_DISABLE((op_flags & 0xff) >= DUK_BC_OP_MIN);  /* unsigned */
        DUK_ASSERT((op_flags & 0xff) <= DUK_BC_OP_MAX);
        DUK_ASSERT_DISABLE(bc >= DUK_BC_BC_MIN);  /* unsigned */
        DUK_ASSERT(bc <= DUK_BC_BC_MAX);
        DUK_ASSERT((bc & DUK__CONST_MARKER) == 0);

        if (bc <= DUK_BC_BC_MAX) {
                ;
        } else {
                /* No BC shuffling now. */
                goto error_outofregs;
        }

#if defined(DUK_USE_SHUFFLE_TORTURE)
        if (a <= DUK_BC_A_MAX && (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_A)) {
#else
        if (a <= DUK_BC_A_MAX) {
#endif
                ins = DUK_ENC_OP_A_BC(op_flags & 0xff, a, bc);
                duk__emit(comp_ctx, ins);
        } else if (op_flags & DUK__EMIT_FLAG_NO_SHUFFLE_A) {
                goto error_outofregs;
        } else if (a <= DUK_BC_BC_MAX) {
                comp_ctx->curr_func.needs_shuffle = 1;
                tmp = comp_ctx->curr_func.shuffle1;
                ins = DUK_ENC_OP_A_BC(op_flags & 0xff, tmp, bc);
                if (op_flags & DUK__EMIT_FLAG_A_IS_SOURCE) {
                        duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_LDREG, tmp, a));
                        duk__emit(comp_ctx, ins);
                } else {
                        duk__emit(comp_ctx, ins);
                        duk__emit(comp_ctx, DUK_ENC_OP_A_BC(DUK_OP_STREG, tmp, a));
                }
        } else {
                goto error_outofregs;
        }
        return;

 error_outofregs:
        DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_REG_LIMIT);
}

DUK_LOCAL void duk__emit_abc(duk_compiler_ctx *comp_ctx, duk_small_uint_t op, duk_regconst_t abc) {
        duk_instr_t ins;

        DUK_ASSERT_DISABLE(op >= DUK_BC_OP_MIN);  /* unsigned */
        DUK_ASSERT(op <= DUK_BC_OP_MAX);
        DUK_ASSERT_DISABLE(abc >= DUK_BC_ABC_MIN);  /* unsigned */
        DUK_ASSERT(abc <= DUK_BC_ABC_MAX);
        DUK_ASSERT((abc & DUK__CONST_MARKER) == 0);

        if (abc <= DUK_BC_ABC_MAX) {
                ;
        } else {
                goto error_outofregs;
        }
        ins = DUK_ENC_OP_ABC(op, abc);
        DUK_DDD(DUK_DDDPRINT("duk__emit_abc: 0x%08lx line=%ld pc=%ld op=%ld (%!C) abc=%ld (%!I)",
                             (unsigned long) ins, (long) comp_ctx->curr_token.start_line,
                             (long) duk__get_current_pc(comp_ctx), (long) op, (long) op,
                             (long) abc, (duk_instr_t) ins));
        duk__emit(comp_ctx, ins);
        return;

 error_outofregs:
        DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_REG_LIMIT);
}

DUK_LOCAL void duk__emit_extraop_b_c(duk_compiler_ctx *comp_ctx, duk_small_uint_t extraop_flags, duk_regconst_t b, duk_regconst_t c) {
        DUK_ASSERT_DISABLE((extraop_flags & 0xff) >= DUK_BC_EXTRAOP_MIN);  /* unsigned */
        DUK_ASSERT((extraop_flags & 0xff) <= DUK_BC_EXTRAOP_MAX);
        /* Setting "no shuffle A" is covered by the assert, but it's needed
         * with DUK_USE_SHUFFLE_TORTURE.
         */
        duk__emit_a_b_c(comp_ctx,
                        DUK_OP_EXTRA | DUK__EMIT_FLAG_NO_SHUFFLE_A | (extraop_flags & ~0xff),  /* transfer flags */
                        extraop_flags & 0xff,
                        b,
                        c);
}

DUK_LOCAL void duk__emit_extraop_b(duk_compiler_ctx *comp_ctx, duk_small_uint_t extraop_flags, duk_regconst_t b) {
        DUK_ASSERT_DISABLE((extraop_flags & 0xff) >= DUK_BC_EXTRAOP_MIN);  /* unsigned */
        DUK_ASSERT((extraop_flags & 0xff) <= DUK_BC_EXTRAOP_MAX);
        /* Setting "no shuffle A" is covered by the assert, but it's needed
         * with DUK_USE_SHUFFLE_TORTURE.
         */
        duk__emit_a_b_c(comp_ctx,
                        DUK_OP_EXTRA | DUK__EMIT_FLAG_NO_SHUFFLE_A | (extraop_flags & ~0xff),  /* transfer flags */
                        extraop_flags & 0xff,
                        b,
                        0);
}

DUK_LOCAL void duk__emit_extraop_bc(duk_compiler_ctx *comp_ctx, duk_small_uint_t extraop, duk_regconst_t bc) {
        DUK_ASSERT_DISABLE(extraop >= DUK_BC_EXTRAOP_MIN);  /* unsigned */
        DUK_ASSERT(extraop <= DUK_BC_EXTRAOP_MAX);
        /* Setting "no shuffle A" is covered by the assert, but it's needed
         * with DUK_USE_SHUFFLE_TORTURE.
         */
        duk__emit_a_bc(comp_ctx,
                       DUK_OP_EXTRA | DUK__EMIT_FLAG_NO_SHUFFLE_A,
                       extraop,
                       bc);
}

DUK_LOCAL void duk__emit_extraop_only(duk_compiler_ctx *comp_ctx, duk_small_uint_t extraop_flags) {
        DUK_ASSERT_DISABLE((extraop_flags & 0xff) >= DUK_BC_EXTRAOP_MIN);  /* unsigned */
        DUK_ASSERT((extraop_flags & 0xff) <= DUK_BC_EXTRAOP_MAX);
        /* Setting "no shuffle A" is covered by the assert, but it's needed
         * with DUK_USE_SHUFFLE_TORTURE.
         */
        duk__emit_a_b_c(comp_ctx,
                        DUK_OP_EXTRA | DUK__EMIT_FLAG_NO_SHUFFLE_A | DUK__EMIT_FLAG_NO_SHUFFLE_B |
                            DUK__EMIT_FLAG_NO_SHUFFLE_C | (extraop_flags & ~0xff),  /* transfer flags */
                        extraop_flags & 0xff,
                        0,
                        0);
}

DUK_LOCAL void duk__emit_load_int32_raw(duk_compiler_ctx *comp_ctx, duk_reg_t reg, duk_int32_t val, duk_small_uint_t op_flags) {
        /* XXX: Shuffling support could be implemented here so that LDINT+LDINTX
         * would only shuffle once (instead of twice).  The current code works
         * though, and has a smaller compiler footprint.
         */

        if ((val >= (duk_int32_t) DUK_BC_BC_MIN - (duk_int32_t) DUK_BC_LDINT_BIAS) &&
            (val <= (duk_int32_t) DUK_BC_BC_MAX - (duk_int32_t) DUK_BC_LDINT_BIAS)) {
                DUK_DDD(DUK_DDDPRINT("emit LDINT to reg %ld for %ld", (long) reg, (long) val));
                duk__emit_a_bc(comp_ctx, DUK_OP_LDINT | op_flags, reg, (duk_regconst_t) (val + (duk_int32_t) DUK_BC_LDINT_BIAS));
        } else {
                duk_int32_t hi = val >> DUK_BC_LDINTX_SHIFT;
                duk_int32_t lo = val & ((((duk_int32_t) 1) << DUK_BC_LDINTX_SHIFT) - 1);
                DUK_ASSERT(lo >= 0);
                DUK_DDD(DUK_DDDPRINT("emit LDINT+LDINTX to reg %ld for %ld -> hi %ld, lo %ld",
                                     (long) reg, (long) val, (long) hi, (long) lo));
                duk__emit_a_bc(comp_ctx, DUK_OP_LDINT | op_flags, reg, (duk_regconst_t) (hi + (duk_int32_t) DUK_BC_LDINT_BIAS));
                duk__emit_a_bc(comp_ctx, DUK_OP_LDINTX | op_flags, reg, (duk_regconst_t) lo);
        }
}

DUK_LOCAL void duk__emit_load_int32(duk_compiler_ctx *comp_ctx, duk_reg_t reg, duk_int32_t val) {
        duk__emit_load_int32_raw(comp_ctx, reg, val, 0 /*op_flags*/);
}

#if defined(DUK_USE_SHUFFLE_TORTURE)
/* Used by duk__emit*() calls so that we don't shuffle the loadints that
 * are needed to handle indirect opcodes.
 */
DUK_LOCAL void duk__emit_load_int32_noshuffle(duk_compiler_ctx *comp_ctx, duk_reg_t reg, duk_int32_t val) {
        duk__emit_load_int32_raw(comp_ctx, reg, val, DUK__EMIT_FLAG_NO_SHUFFLE_A /*op_flags*/);
}
#else
DUK_LOCAL void duk__emit_load_int32_noshuffle(duk_compiler_ctx *comp_ctx, duk_reg_t reg, duk_int32_t val) {
        /* When torture not enabled, can just use the same helper because
         * 'reg' won't get spilled.
         */
        DUK_ASSERT(reg <= DUK_BC_A_MAX);
        duk__emit_load_int32(comp_ctx, reg, val);
}
#endif

DUK_LOCAL void duk__emit_jump(duk_compiler_ctx *comp_ctx, duk_int_t target_pc) {
        duk_int_t curr_pc;
        duk_int_t offset;

        curr_pc = (duk_int_t) (DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) / sizeof(duk_compiler_instr));
        offset = (duk_int_t) target_pc - (duk_int_t) curr_pc - 1;
        DUK_ASSERT(offset + DUK_BC_JUMP_BIAS >= DUK_BC_ABC_MIN);
        DUK_ASSERT(offset + DUK_BC_JUMP_BIAS <= DUK_BC_ABC_MAX);
        duk__emit_abc(comp_ctx, DUK_OP_JUMP, (duk_regconst_t) (offset + DUK_BC_JUMP_BIAS));
}

DUK_LOCAL duk_int_t duk__emit_jump_empty(duk_compiler_ctx *comp_ctx) {
        duk_int_t ret;

        ret = duk__get_current_pc(comp_ctx);  /* useful for patching jumps later */
        duk__emit_abc(comp_ctx, DUK_OP_JUMP, 0);
        return ret;
}

/* Insert an empty jump in the middle of code emitted earlier.  This is
 * currently needed for compiling for-in.
 */
DUK_LOCAL void duk__insert_jump_entry(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc) {
#if defined(DUK_USE_PC2LINE)
        duk_int_t line;
#endif
        duk_compiler_instr *instr;
        duk_size_t offset;

        offset = jump_pc * sizeof(duk_compiler_instr),
        instr = (duk_compiler_instr *) (void *)
                DUK_BW_INSERT_ENSURE_AREA(comp_ctx->thr,
                                          &comp_ctx->curr_func.bw_code,
                                          offset,
                                          sizeof(duk_compiler_instr));

#if defined(DUK_USE_PC2LINE)
        line = comp_ctx->curr_token.start_line;  /* approximation, close enough */
#endif
        instr->ins = DUK_ENC_OP_ABC(DUK_OP_JUMP, 0);
#if defined(DUK_USE_PC2LINE)
        instr->line = line;
#endif

        DUK_BW_ADD_PTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code, sizeof(duk_compiler_instr));
        if (DUK_UNLIKELY(DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) > DUK_USE_ESBC_MAX_BYTES)) {
                goto fail_bc_limit;
        }
        return;

  fail_bc_limit:
        DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_BYTECODE_LIMIT);
}

/* Does not assume that jump_pc contains a DUK_OP_JUMP previously; this is intentional
 * to allow e.g. an INVALID opcode be overwritten with a JUMP (label management uses this).
 */
DUK_LOCAL void duk__patch_jump(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc, duk_int_t target_pc) {
        duk_compiler_instr *instr;
        duk_int_t offset;

        /* allow negative PCs, behave as a no-op */
        if (jump_pc < 0) {
                DUK_DDD(DUK_DDDPRINT("duk__patch_jump(): nop call, jump_pc=%ld (<0), target_pc=%ld",
                                     (long) jump_pc, (long) target_pc));
                return;
        }
        DUK_ASSERT(jump_pc >= 0);

        /* XXX: range assert */
        instr = duk__get_instr_ptr(comp_ctx, jump_pc);
        DUK_ASSERT(instr != NULL);

        /* XXX: range assert */
        offset = target_pc - jump_pc - 1;

        instr->ins = DUK_ENC_OP_ABC(DUK_OP_JUMP, offset + DUK_BC_JUMP_BIAS);
        DUK_DDD(DUK_DDDPRINT("duk__patch_jump(): jump_pc=%ld, target_pc=%ld, offset=%ld",
                             (long) jump_pc, (long) target_pc, (long) offset));
}

DUK_LOCAL void duk__patch_jump_here(duk_compiler_ctx *comp_ctx, duk_int_t jump_pc) {
        duk__patch_jump(comp_ctx, jump_pc, duk__get_current_pc(comp_ctx));
}

DUK_LOCAL void duk__patch_trycatch(duk_compiler_ctx *comp_ctx, duk_int_t ldconst_pc, duk_int_t trycatch_pc, duk_regconst_t reg_catch, duk_regconst_t const_varname, duk_small_uint_t flags) {
        duk_compiler_instr *instr;

        DUK_ASSERT((reg_catch & DUK__CONST_MARKER) == 0);

        instr = duk__get_instr_ptr(comp_ctx, ldconst_pc);
        DUK_ASSERT(DUK_DEC_OP(instr->ins) == DUK_OP_LDCONST);
        DUK_ASSERT(instr != NULL);
        if (const_varname & DUK__CONST_MARKER) {
                /* Have a catch variable. */
                const_varname = const_varname & (~DUK__CONST_MARKER);
                if (reg_catch > DUK_BC_BC_MAX || const_varname > DUK_BC_BC_MAX) {
                        /* Catch attempts to use out-of-range reg/const.  Without this
                         * check Duktape 0.12.0 could generate invalid code which caused
                         * an assert failure on execution.  This error is triggered e.g.
                         * for functions with a lot of constants and a try-catch statement.
                         * Shuffling or opcode semantics change is needed to fix the issue.
                         * See: test-bug-trycatch-many-constants.js.
                         */
                        DUK_D(DUK_DPRINT("failed to patch trycatch: flags=%ld, reg_catch=%ld, const_varname=%ld (0x%08lx)",
                                         (long) flags, (long) reg_catch, (long) const_varname, (long) const_varname));
                        DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_REG_LIMIT);
                }
                instr->ins |= DUK_ENC_OP_A_BC(0, 0, const_varname);
        } else {
                /* No catch variable, e.g. a try-finally; replace LDCONST with
                 * NOP to avoid a bogus LDCONST.
                 */
                instr->ins = DUK_ENC_OP_A(DUK_OP_EXTRA, DUK_EXTRAOP_NOP);
        }

        instr = duk__get_instr_ptr(comp_ctx, trycatch_pc);
        DUK_ASSERT(instr != NULL);
        DUK_ASSERT_DISABLE(flags >= DUK_BC_A_MIN);
        DUK_ASSERT(flags <= DUK_BC_A_MAX);
        instr->ins = DUK_ENC_OP_A_BC(DUK_OP_TRYCATCH, flags, reg_catch);
}

DUK_LOCAL void duk__emit_if_false_skip(duk_compiler_ctx *comp_ctx, duk_regconst_t regconst) {
        duk__emit_a_b_c(comp_ctx,
                        DUK_OP_IF | DUK__EMIT_FLAG_NO_SHUFFLE_A | DUK__EMIT_FLAG_NO_SHUFFLE_C,
                        0 /*false*/,
                        regconst,
                        0 /*unused*/);
}

DUK_LOCAL void duk__emit_if_true_skip(duk_compiler_ctx *comp_ctx, duk_regconst_t regconst) {
        duk__emit_a_b_c(comp_ctx,
                        DUK_OP_IF | DUK__EMIT_FLAG_NO_SHUFFLE_A | DUK__EMIT_FLAG_NO_SHUFFLE_C,
                        1 /*true*/,
                        regconst,
                        0 /*unused*/);
}

DUK_LOCAL void duk__emit_invalid(duk_compiler_ctx *comp_ctx) {
        duk__emit_extraop_bc(comp_ctx, DUK_EXTRAOP_INVALID, 0);
}

/*
 *  Peephole optimizer for finished bytecode.
 *
 *  Does not remove opcodes; currently only straightens out unconditional
 *  jump chains which are generated by several control structures.
 */

DUK_LOCAL void duk__peephole_optimize_bytecode(duk_compiler_ctx *comp_ctx) {
        duk_compiler_instr *bc;
        duk_small_uint_t iter;
        duk_int_t i, n;
        duk_int_t count_opt;

        bc = (duk_compiler_instr *) (void *) DUK_BW_GET_BASEPTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code);
#if defined(DUK_USE_BUFLEN16)
        /* No need to assert, buffer size maximum is 0xffff. */
#else
        DUK_ASSERT((duk_size_t) DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) / sizeof(duk_compiler_instr) <= (duk_size_t) DUK_INT_MAX);  /* bytecode limits */
#endif
        n = (duk_int_t) (DUK_BW_GET_SIZE(comp_ctx->thr, &comp_ctx->curr_func.bw_code) / sizeof(duk_compiler_instr));

        for (iter = 0; iter < DUK_COMPILER_PEEPHOLE_MAXITER; iter++) {
                count_opt = 0;

                for (i = 0; i < n; i++) {
                        duk_instr_t ins;
                        duk_int_t target_pc1;
                        duk_int_t target_pc2;

                        ins = bc[i].ins;
                        if (DUK_DEC_OP(ins) != DUK_OP_JUMP) {
                                continue;
                        }

                        target_pc1 = i + 1 + DUK_DEC_ABC(ins) - DUK_BC_JUMP_BIAS;
                        DUK_DDD(DUK_DDDPRINT("consider jump at pc %ld; target_pc=%ld", (long) i, (long) target_pc1));
                        DUK_ASSERT(target_pc1 >= 0);
                        DUK_ASSERT(target_pc1 < n);

                        /* Note: if target_pc1 == i, we'll optimize a jump to itself.
                         * This does not need to be checked for explicitly; the case
                         * is rare and max iter breaks us out.
                         */

                        ins = bc[target_pc1].ins;
                        if (DUK_DEC_OP(ins) != DUK_OP_JUMP) {
                                continue;
                        }

                        target_pc2 = target_pc1 + 1 + DUK_DEC_ABC(ins) - DUK_BC_JUMP_BIAS;

                        DUK_DDD(DUK_DDDPRINT("optimizing jump at pc %ld; old target is %ld -> new target is %ld",
                                             (long) i, (long) target_pc1, (long) target_pc2));

                        bc[i].ins = DUK_ENC_OP_ABC(DUK_OP_JUMP, target_pc2 - (i + 1) + DUK_BC_JUMP_BIAS);

                        count_opt++;
                }

                DUK_DD(DUK_DDPRINT("optimized %ld jumps on peephole round %ld", (long) count_opt, (long) (iter + 1)));

                if (count_opt == 0) {
                        break;
                }
        }
}

/*
 *  Intermediate value helpers
 */

#define DUK__ISREG(comp_ctx,x)              (((x) & DUK__CONST_MARKER) == 0)
#define DUK__ISCONST(comp_ctx,x)            (((x) & DUK__CONST_MARKER) != 0)
#define DUK__ISTEMP(comp_ctx,x)             (DUK__ISREG((comp_ctx), (x)) && (duk_regconst_t) (x) >= (duk_regconst_t) ((comp_ctx)->curr_func.temp_first))
#define DUK__GETTEMP(comp_ctx)              ((comp_ctx)->curr_func.temp_next)
#define DUK__SETTEMP(comp_ctx,x)            ((comp_ctx)->curr_func.temp_next = (x))  /* dangerous: must only lower (temp_max not updated) */
#define DUK__SETTEMP_CHECKMAX(comp_ctx,x)   duk__settemp_checkmax((comp_ctx),(x))
#define DUK__ALLOCTEMP(comp_ctx)            duk__alloctemp((comp_ctx))
#define DUK__ALLOCTEMPS(comp_ctx,count)     duk__alloctemps((comp_ctx),(count))

/* Flags for intermediate value coercions.  A flag for using a forced reg
 * is not needed, the forced_reg argument suffices and generates better
 * code (it is checked as it is used).
 */
#define DUK__IVAL_FLAG_ALLOW_CONST          (1 << 0)  /* allow a constant to be returned */
#define DUK__IVAL_FLAG_REQUIRE_TEMP         (1 << 1)  /* require a (mutable) temporary as a result (or a const if allowed) */
#define DUK__IVAL_FLAG_REQUIRE_SHORT        (1 << 2)  /* require a short (8-bit) reg/const which fits into bytecode B/C slot */

/* XXX: some code might benefit from DUK__SETTEMP_IFTEMP(ctx,x) */

#if 0  /* enable manually for dumping */
#define DUK__DUMP_ISPEC(compctx,ispec) do { duk__dump_ispec((compctx), (ispec)); } while (0)
#define DUK__DUMP_IVALUE(compctx,ivalue) do { duk__dump_ivalue((compctx), (ivalue)); } while (0)

DUK_LOCAL void duk__dump_ispec(duk_compiler_ctx *comp_ctx, duk_ispec *x) {
        DUK_D(DUK_DPRINT("ispec dump: t=%ld regconst=0x%08lx, valstack_idx=%ld, value=%!T",
                         (long) x->t, (unsigned long) x->regconst, (long) x->valstack_idx,
                         duk_get_tval((duk_context *) comp_ctx->thr, x->valstack_idx)));
}
DUK_LOCAL void duk__dump_ivalue(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
        DUK_D(DUK_DPRINT("ivalue dump: t=%ld op=%ld "
                         "x1={t=%ld regconst=0x%08lx valstack_idx=%ld value=%!T} "
                         "x2={t=%ld regconst=0x%08lx valstack_idx=%ld value=%!T}",
                         (long) x->t, (long) x->op,
                         (long) x->x1.t, (unsigned long) x->x1.regconst, (long) x->x1.valstack_idx,
                         duk_get_tval((duk_context *) comp_ctx->thr, x->x1.valstack_idx),
                         (long) x->x2.t, (unsigned long) x->x2.regconst, (long) x->x2.valstack_idx,
                         duk_get_tval((duk_context *) comp_ctx->thr, x->x2.valstack_idx)));
}
#else
#define DUK__DUMP_ISPEC(comp_ctx,x) do {} while (0)
#define DUK__DUMP_IVALUE(comp_ctx,x) do {} while (0)
#endif

DUK_LOCAL void duk__copy_ispec(duk_compiler_ctx *comp_ctx, duk_ispec *src, duk_ispec *dst) {
        duk_context *ctx = (duk_context *) comp_ctx->thr;

        dst->t = src->t;
        dst->regconst = src->regconst;
        duk_copy(ctx, src->valstack_idx, dst->valstack_idx);
}

DUK_LOCAL void duk__copy_ivalue(duk_compiler_ctx *comp_ctx, duk_ivalue *src, duk_ivalue *dst) {
        duk_context *ctx = (duk_context *) comp_ctx->thr;

        dst->t = src->t;
        dst->op = src->op;
        dst->x1.t = src->x1.t;
        dst->x1.regconst = src->x1.regconst;
        dst->x2.t = src->x2.t;
        dst->x2.regconst = src->x2.regconst;
        duk_copy(ctx, src->x1.valstack_idx, dst->x1.valstack_idx);
        duk_copy(ctx, src->x2.valstack_idx, dst->x2.valstack_idx);
}

/* XXX: to util */
DUK_LOCAL duk_bool_t duk__is_whole_get_int32(duk_double_t x, duk_int32_t *ival) {
        duk_small_int_t c;
        duk_int32_t t;

        c = DUK_FPCLASSIFY(x);
        if (c == DUK_FP_NORMAL || (c == DUK_FP_ZERO && !DUK_SIGNBIT(x))) {
                /* Don't allow negative zero as it will cause trouble with
                 * LDINT+LDINTX.  But positive zero is OK.
                 */
                t = (duk_int32_t) x;
                if ((duk_double_t) t == x) {
                        *ival = t;
                        return 1;
                }
        }

        return 0;
}

DUK_LOCAL duk_reg_t duk__alloctemps(duk_compiler_ctx *comp_ctx, duk_small_int_t num) {
        duk_reg_t res;

        res = comp_ctx->curr_func.temp_next;
        comp_ctx->curr_func.temp_next += num;

        if (comp_ctx->curr_func.temp_next > DUK__MAX_TEMPS) {  /* == DUK__MAX_TEMPS is OK */
                DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_TEMP_LIMIT);
        }

        /* maintain highest 'used' temporary, needed to figure out nregs of function */
        if (comp_ctx->curr_func.temp_next > comp_ctx->curr_func.temp_max) {
                comp_ctx->curr_func.temp_max = comp_ctx->curr_func.temp_next;
        }

        return res;
}

DUK_LOCAL duk_reg_t duk__alloctemp(duk_compiler_ctx *comp_ctx) {
        return duk__alloctemps(comp_ctx, 1);
}

DUK_LOCAL void duk__settemp_checkmax(duk_compiler_ctx *comp_ctx, duk_reg_t temp_next) {
        comp_ctx->curr_func.temp_next = temp_next;
        if (temp_next > comp_ctx->curr_func.temp_max) {
                comp_ctx->curr_func.temp_max = temp_next;
        }
}

/* get const for value at valstack top */
DUK_LOCAL duk_regconst_t duk__getconst(duk_compiler_ctx *comp_ctx) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_compiler_func *f = &comp_ctx->curr_func;
        duk_tval *tv1;
        duk_int_t i, n, n_check;

        n = (duk_int_t) duk_get_length(ctx, f->consts_idx);

        tv1 = DUK_GET_TVAL_NEGIDX(ctx, -1);
        DUK_ASSERT(tv1 != NULL);

#if defined(DUK_USE_FASTINT)
        /* Explicit check for fastint downgrade. */
        DUK_TVAL_CHKFAST_INPLACE(tv1);
#endif

        /* Sanity workaround for handling functions with a large number of
         * constants at least somewhat reasonably.  Otherwise checking whether
         * we already have the constant would grow very slow (as it is O(N^2)).
         */
        n_check = (n > DUK__GETCONST_MAX_CONSTS_CHECK ? DUK__GETCONST_MAX_CONSTS_CHECK : n);
        for (i = 0; i < n_check; i++) {
                duk_tval *tv2 = DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, f->h_consts, i);

                /* Strict equality is NOT enough, because we cannot use the same
                 * constant for e.g. +0 and -0.
                 */
                if (duk_js_samevalue(tv1, tv2)) {
                        DUK_DDD(DUK_DDDPRINT("reused existing constant for %!T -> const index %ld",
                                             (duk_tval *) tv1, (long) i));
                        duk_pop(ctx);
                        return (duk_regconst_t) (i | DUK__CONST_MARKER);
                }
        }

        if (n > DUK__MAX_CONSTS) {
                DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_CONST_LIMIT);
        }

        DUK_DDD(DUK_DDDPRINT("allocating new constant for %!T -> const index %ld",
                             (duk_tval *) tv1, (long) n));
        (void) duk_put_prop_index(ctx, f->consts_idx, n);  /* invalidates tv1, tv2 */
        return (duk_regconst_t) (n | DUK__CONST_MARKER);
}

/* Get the value represented by an duk_ispec to a register or constant.
 * The caller can control the result by indicating whether or not:
 *
 *   (1) a constant is allowed (sometimes the caller needs the result to
 *       be in a register)
 *
 *   (2) a temporary register is required (usually when caller requires
 *       the register to be safely mutable; normally either a bound
 *       register or a temporary register are both OK)
 *
 *   (3) a forced register target needs to be used
 *
 * Bytecode may be emitted to generate the necessary value.  The return
 * value is either a register or a constant.
 */

DUK_LOCAL
duk_regconst_t duk__ispec_toregconst_raw(duk_compiler_ctx *comp_ctx,
                                         duk_ispec *x,
                                         duk_reg_t forced_reg,
                                         duk_small_uint_t flags) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;

        DUK_DDD(DUK_DDDPRINT("duk__ispec_toregconst_raw(): x={%ld:%ld:%!T}, "
                             "forced_reg=%ld, flags 0x%08lx: allow_const=%ld require_temp=%ld require_short=%ld",
                             (long) x->t,
                             (long) x->regconst,
                             (duk_tval *) duk_get_tval(ctx, x->valstack_idx),
                             (long) forced_reg,
                             (unsigned long) flags,
                             (long) ((flags & DUK__IVAL_FLAG_ALLOW_CONST) ? 1 : 0),
                             (long) ((flags & DUK__IVAL_FLAG_REQUIRE_TEMP) ? 1 : 0),
                             (long) ((flags & DUK__IVAL_FLAG_REQUIRE_SHORT) ? 1 : 0)));

        switch (x->t) {
        case DUK_ISPEC_VALUE: {
                duk_tval *tv;

                tv = DUK_GET_TVAL_POSIDX(ctx, x->valstack_idx);
                DUK_ASSERT(tv != NULL);

                switch (DUK_TVAL_GET_TAG(tv)) {
                case DUK_TAG_UNDEFINED: {
                        /* Note: although there is no 'undefined' literal, undefined
                         * values can occur during compilation as a result of e.g.
                         * the 'void' operator.
                         */
                        duk_reg_t dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
                        duk__emit_extraop_bc(comp_ctx, DUK_EXTRAOP_LDUNDEF, (duk_regconst_t) dest);
                        return (duk_regconst_t) dest;
                }
                case DUK_TAG_NULL: {
                        duk_reg_t dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
                        duk__emit_extraop_bc(comp_ctx, DUK_EXTRAOP_LDNULL, (duk_regconst_t) dest);
                        return (duk_regconst_t) dest;
                }
                case DUK_TAG_BOOLEAN: {
                        duk_reg_t dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
                        duk__emit_extraop_bc(comp_ctx,
                                             (DUK_TVAL_GET_BOOLEAN(tv) ? DUK_EXTRAOP_LDTRUE : DUK_EXTRAOP_LDFALSE),
                                             (duk_regconst_t) dest);
                        return (duk_regconst_t) dest;
                }
                case DUK_TAG_POINTER: {
                        DUK_UNREACHABLE();
                        break;
                }
                case DUK_TAG_STRING: {
                        duk_hstring *h;
                        duk_reg_t dest;
                        duk_regconst_t constidx;

                        h = DUK_TVAL_GET_STRING(tv);
                        DUK_UNREF(h);
                        DUK_ASSERT(h != NULL);

#if 0  /* XXX: to be implemented? */
                        /* Use special opcodes to load short strings */
                        if (DUK_HSTRING_GET_BYTELEN(h) <= 2) {
                                /* Encode into a single opcode (18 bits can encode 1-2 bytes + length indicator) */
                        } else if (DUK_HSTRING_GET_BYTELEN(h) <= 6) {
                                /* Encode into a double constant (53 bits can encode 6*8 = 48 bits + 3-bit length */
                        }
#endif
                        duk_dup(ctx, x->valstack_idx);
                        constidx = duk__getconst(comp_ctx);

                        if (flags & DUK__IVAL_FLAG_ALLOW_CONST) {
                                return constidx;
                        }

                        dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
                        duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, (duk_regconst_t) dest, constidx);
                        return (duk_regconst_t) dest;
                }
                case DUK_TAG_OBJECT: {
                        DUK_UNREACHABLE();
                        break;
                }
                case DUK_TAG_BUFFER: {
                        DUK_UNREACHABLE();
                        break;
                }
                case DUK_TAG_LIGHTFUNC: {
                        DUK_UNREACHABLE();
                        break;
                }
#if defined(DUK_USE_FASTINT)
                case DUK_TAG_FASTINT:
#endif
                default: {
                        /* number */
                        duk_reg_t dest;
                        duk_regconst_t constidx;
                        duk_double_t dval;
                        duk_int32_t ival;

                        DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv));
                        DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
                        dval = DUK_TVAL_GET_NUMBER(tv);

                        if (!(flags & DUK__IVAL_FLAG_ALLOW_CONST)) {
                                /* A number can be loaded either through a constant, using
                                 * LDINT, or using LDINT+LDINTX.  LDINT is always a size win,
                                 * LDINT+LDINTX is not if the constant is used multiple times.
                                 * Currently always prefer LDINT+LDINTX over a double constant.
                                 */

                                if (duk__is_whole_get_int32(dval, &ival)) {
                                        dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
                                        duk__emit_load_int32(comp_ctx, dest, ival);
                                        return (duk_regconst_t) dest;
                                }
                        }

                        duk_dup(ctx, x->valstack_idx);
                        constidx = duk__getconst(comp_ctx);

                        if (flags & DUK__IVAL_FLAG_ALLOW_CONST) {
                                return constidx;
                        } else {
                                dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
                                duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, (duk_regconst_t) dest, constidx);
                                return (duk_regconst_t) dest;
                        }
                }
                }  /* end switch */
        }
        case DUK_ISPEC_REGCONST: {
                if (forced_reg >= 0) {
                        if (x->regconst & DUK__CONST_MARKER) {
                                duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, forced_reg, x->regconst);
                        } else if (x->regconst != (duk_regconst_t) forced_reg) {
                                duk__emit_a_bc(comp_ctx, DUK_OP_LDREG, forced_reg, x->regconst);
                        } else {
                                ; /* already in correct reg */
                        }
                        return (duk_regconst_t) forced_reg;
                }

                DUK_ASSERT(forced_reg < 0);
                if (x->regconst & DUK__CONST_MARKER) {
                        if (!(flags & DUK__IVAL_FLAG_ALLOW_CONST)) {
                                duk_reg_t dest = DUK__ALLOCTEMP(comp_ctx);
                                duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, (duk_regconst_t) dest, x->regconst);
                                return (duk_regconst_t) dest;
                        }
                        return x->regconst;
                }

                DUK_ASSERT(forced_reg < 0 && !(x->regconst & DUK__CONST_MARKER));
                if ((flags & DUK__IVAL_FLAG_REQUIRE_TEMP) && !DUK__ISTEMP(comp_ctx, x->regconst)) {
                        duk_reg_t dest = DUK__ALLOCTEMP(comp_ctx);
                        duk__emit_a_bc(comp_ctx, DUK_OP_LDREG, (duk_regconst_t) dest, x->regconst);
                        return (duk_regconst_t) dest;
                }
                return x->regconst;
        }
        default: {
                break;
        }
        }

        DUK_ERROR_INTERNAL_DEFMSG(thr);
        return 0;
}

DUK_LOCAL void duk__ispec_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ispec *x, duk_reg_t forced_reg) {
        DUK_ASSERT(forced_reg >= 0);
        (void) duk__ispec_toregconst_raw(comp_ctx, x, forced_reg, 0 /*flags*/);
}

/* Coerce an duk_ivalue to a 'plain' value by generating the necessary
 * arithmetic operations, property access, or variable access bytecode.
 * The duk_ivalue argument ('x') is converted into a plain value as a
 * side effect.
 */
DUK_LOCAL void duk__ivalue_toplain_raw(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_reg_t forced_reg) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;

        DUK_DDD(DUK_DDDPRINT("duk__ivalue_toplain_raw(): x={t=%ld,op=%ld,x1={%ld:%ld:%!T},x2={%ld:%ld:%!T}}, "
                             "forced_reg=%ld",
                             (long) x->t, (long) x->op,
                             (long) x->x1.t, (long) x->x1.regconst,
                             (duk_tval *) duk_get_tval(ctx, x->x1.valstack_idx),
                             (long) x->x2.t, (long) x->x2.regconst,
                             (duk_tval *) duk_get_tval(ctx, x->x2.valstack_idx),
                             (long) forced_reg));

        switch (x->t) {
        case DUK_IVAL_PLAIN: {
                return;
        }
        /* XXX: support unary arithmetic ivalues (useful?) */
        case DUK_IVAL_ARITH:
        case DUK_IVAL_ARITH_EXTRAOP: {
                duk_regconst_t arg1;
                duk_regconst_t arg2;
                duk_reg_t dest;
                duk_tval *tv1;
                duk_tval *tv2;

                DUK_DDD(DUK_DDDPRINT("arith to plain conversion"));

                /* inline arithmetic check for constant values */
                /* XXX: use the exactly same arithmetic function here as in executor */
                if (x->x1.t == DUK_ISPEC_VALUE && x->x2.t == DUK_ISPEC_VALUE && x->t == DUK_IVAL_ARITH) {
                        tv1 = DUK_GET_TVAL_POSIDX(ctx, x->x1.valstack_idx);
                        tv2 = DUK_GET_TVAL_POSIDX(ctx, x->x2.valstack_idx);
                        DUK_ASSERT(tv1 != NULL);
                        DUK_ASSERT(tv2 != NULL);

                        DUK_DDD(DUK_DDDPRINT("arith: tv1=%!T, tv2=%!T",
                                             (duk_tval *) tv1,
                                             (duk_tval *) tv2));

                        if (DUK_TVAL_IS_NUMBER(tv1) && DUK_TVAL_IS_NUMBER(tv2)) {
                                duk_double_t d1 = DUK_TVAL_GET_NUMBER(tv1);
                                duk_double_t d2 = DUK_TVAL_GET_NUMBER(tv2);
                                duk_double_t d3;
                                duk_bool_t accept = 1;

                                DUK_DDD(DUK_DDDPRINT("arith inline check: d1=%lf, d2=%lf, op=%ld",
                                                     (double) d1, (double) d2, (long) x->op));
                                switch (x->op) {
                                case DUK_OP_ADD:  d3 = d1 + d2; break;
                                case DUK_OP_SUB:  d3 = d1 - d2; break;
                                case DUK_OP_MUL:  d3 = d1 * d2; break;
                                case DUK_OP_DIV:  d3 = d1 / d2; break;
                                default:          accept = 0; break;
                                }

                                if (accept) {
                                        duk_double_union du;
                                        du.d = d3;
                                        DUK_DBLUNION_NORMALIZE_NAN_CHECK(&du);
                                        d3 = du.d;

                                        x->t = DUK_IVAL_PLAIN;
                                        DUK_ASSERT(x->x1.t == DUK_ISPEC_VALUE);
                                        DUK_TVAL_SET_NUMBER(tv1, d3);  /* old value is number: no refcount */
                                        return;
                                }
                        } else if (x->op == DUK_OP_ADD && DUK_TVAL_IS_STRING(tv1) && DUK_TVAL_IS_STRING(tv2)) {
                                /* inline string concatenation */
                                duk_dup(ctx, x->x1.valstack_idx);
                                duk_dup(ctx, x->x2.valstack_idx);
                                duk_concat(ctx, 2);
                                duk_replace(ctx, x->x1.valstack_idx);
                                x->t = DUK_IVAL_PLAIN;
                                DUK_ASSERT(x->x1.t == DUK_ISPEC_VALUE);
                                return;
                        }
                }

                arg1 = duk__ispec_toregconst_raw(comp_ctx, &x->x1, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_SHORT /*flags*/);
                arg2 = duk__ispec_toregconst_raw(comp_ctx, &x->x2, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_SHORT /*flags*/);

                /* If forced reg, use it as destination.  Otherwise try to
                 * use either coerced ispec if it is a temporary.
                 *
                 * When using extraops, avoid reusing arg2 as dest because that
                 * would lead to an LDREG shuffle below.  We still can't guarantee
                 * dest != arg2 because we may have a forced_reg.
                 */
                if (forced_reg >= 0) {
                        dest = forced_reg;
                } else if (DUK__ISTEMP(comp_ctx, arg1)) {
                        dest = (duk_reg_t) arg1;
                } else if (DUK__ISTEMP(comp_ctx, arg2) && x->t != DUK_IVAL_ARITH_EXTRAOP) {
                        dest = (duk_reg_t) arg2;
                } else {
                        dest = DUK__ALLOCTEMP(comp_ctx);
                }

                /* Extraop arithmetic opcodes must have destination same as
                 * first source.  If second source matches destination we need
                 * a temporary register to avoid clobbering the second source.
                 *
                 * XXX: change calling code to avoid this situation in most cases.
                 */

                if (x->t == DUK_IVAL_ARITH_EXTRAOP) {
                        if (!(DUK__ISREG(comp_ctx, arg1) && (duk_reg_t) arg1 == dest)) {
                                if (DUK__ISREG(comp_ctx, arg2) && (duk_reg_t) arg2 == dest) {
                                        /* arg2 would be clobbered so reassign it to a temp. */
                                        duk_reg_t tempreg;
                                        tempreg = DUK__ALLOCTEMP(comp_ctx);
                                        duk__emit_a_bc(comp_ctx, DUK_OP_LDREG, tempreg, arg2);
                                        arg2 = tempreg;
                                }

                                if (DUK__ISREG(comp_ctx, arg1)) {
                                        duk__emit_a_bc(comp_ctx, DUK_OP_LDREG, dest, arg1);
                                } else {
                                        DUK_ASSERT(DUK__ISCONST(comp_ctx, arg1));
                                        duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, dest, arg1);
                                }
                        }

                        /* Note: special DUK__EMIT_FLAG_B_IS_TARGETSOURCE
                         * used to indicate that B is both a source and a
                         * target register.  When shuffled, it needs to be
                         * both input and output shuffled.
                         */
                        DUK_ASSERT(DUK__ISREG(comp_ctx, dest));
                        duk__emit_extraop_b_c(comp_ctx,
                                              x->op | DUK__EMIT_FLAG_B_IS_TARGET |
                                                      DUK__EMIT_FLAG_B_IS_TARGETSOURCE,
                                              (duk_regconst_t) dest,
                                              (duk_regconst_t) arg2);

                } else {
                        DUK_ASSERT(DUK__ISREG(comp_ctx, dest));
                        duk__emit_a_b_c(comp_ctx, x->op, (duk_regconst_t) dest, arg1, arg2);
                }

                x->t = DUK_IVAL_PLAIN;
                x->x1.t = DUK_ISPEC_REGCONST;
                x->x1.regconst = (duk_regconst_t) dest;
                return;
        }
        case DUK_IVAL_PROP: {
                /* XXX: very similar to DUK_IVAL_ARITH - merge? */
                duk_regconst_t arg1;
                duk_regconst_t arg2;
                duk_reg_t dest;

                /* Need a short reg/const, does not have to be a mutable temp. */
                arg1 = duk__ispec_toregconst_raw(comp_ctx, &x->x1, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_SHORT /*flags*/);
                arg2 = duk__ispec_toregconst_raw(comp_ctx, &x->x2, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_SHORT /*flags*/);

                /* Pick a destination register.  If either base value or key
                 * happens to be a temp value, reuse it as the destination.
                 *
                 * XXX: The temp must be a "mutable" one, i.e. such that no
                 * other expression is using it anymore.  Here this should be
                 * the case because the value of a property access expression
                 * is neither the base nor the key, but the lookup result.
                 */

                if (forced_reg >= 0) {
                        dest = forced_reg;
                } else if (DUK__ISTEMP(comp_ctx, arg1)) {
                        dest = (duk_reg_t) arg1;
                } else if (DUK__ISTEMP(comp_ctx, arg2)) {
                        dest = (duk_reg_t) arg2;
                } else {
                        dest = DUK__ALLOCTEMP(comp_ctx);
                }

                duk__emit_a_b_c(comp_ctx, DUK_OP_GETPROP, (duk_regconst_t) dest, arg1, arg2);

                x->t = DUK_IVAL_PLAIN;
                x->x1.t = DUK_ISPEC_REGCONST;
                x->x1.regconst = (duk_regconst_t) dest;
                return;
        }
        case DUK_IVAL_VAR: {
                /* x1 must be a string */
                duk_reg_t dest;
                duk_reg_t reg_varbind;
                duk_regconst_t rc_varname;

                DUK_ASSERT(x->x1.t == DUK_ISPEC_VALUE);

                duk_dup(ctx, x->x1.valstack_idx);
                if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
                        x->t = DUK_IVAL_PLAIN;
                        x->x1.t = DUK_ISPEC_REGCONST;
                        x->x1.regconst = (duk_regconst_t) reg_varbind;
                } else {
                        dest = (forced_reg >= 0 ? forced_reg : DUK__ALLOCTEMP(comp_ctx));
                        duk__emit_a_bc(comp_ctx, DUK_OP_GETVAR, (duk_regconst_t) dest, rc_varname);
                        x->t = DUK_IVAL_PLAIN;
                        x->x1.t = DUK_ISPEC_REGCONST;
                        x->x1.regconst = (duk_regconst_t) dest;
                }
                return;
        }
        case DUK_IVAL_NONE:
        default: {
                DUK_D(DUK_DPRINT("invalid ivalue type: %ld", (long) x->t));
                break;
        }
        }

        DUK_ERROR_INTERNAL_DEFMSG(thr);
        return;
}

/* evaluate to plain value, no forced register (temp/bound reg both ok) */
DUK_LOCAL void duk__ivalue_toplain(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
        duk__ivalue_toplain_raw(comp_ctx, x, -1 /*forced_reg*/);
}

/* evaluate to final form (e.g. coerce GETPROP to code), throw away temp */
DUK_LOCAL void duk__ivalue_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
        duk_reg_t temp;

        /* If duk__ivalue_toplain_raw() allocates a temp, forget it and
         * restore next temp state.
         */
        temp = DUK__GETTEMP(comp_ctx);
        duk__ivalue_toplain_raw(comp_ctx, x, -1 /*forced_reg*/);
        DUK__SETTEMP(comp_ctx, temp);
}

/* Coerce an duk_ivalue to a register or constant; result register may
 * be a temp or a bound register.
 *
 * The duk_ivalue argument ('x') is converted into a regconst as a
 * side effect.
 */
DUK_LOCAL
duk_regconst_t duk__ivalue_toregconst_raw(duk_compiler_ctx *comp_ctx,
                                          duk_ivalue *x,
                                          duk_reg_t forced_reg,
                                          duk_small_uint_t flags) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_regconst_t reg;
        DUK_UNREF(thr);
        DUK_UNREF(ctx);

        DUK_DDD(DUK_DDDPRINT("duk__ivalue_toregconst_raw(): x={t=%ld,op=%ld,x1={%ld:%ld:%!T},x2={%ld:%ld:%!T}}, "
                             "forced_reg=%ld, flags 0x%08lx: allow_const=%ld require_temp=%ld require_short=%ld",
                             (long) x->t, (long) x->op,
                             (long) x->x1.t, (long) x->x1.regconst,
                             (duk_tval *) duk_get_tval(ctx, x->x1.valstack_idx),
                             (long) x->x2.t, (long) x->x2.regconst,
                             (duk_tval *) duk_get_tval(ctx, x->x2.valstack_idx),
                             (long) forced_reg,
                             (unsigned long) flags,
                             (long) ((flags & DUK__IVAL_FLAG_ALLOW_CONST) ? 1 : 0),
                             (long) ((flags & DUK__IVAL_FLAG_REQUIRE_TEMP) ? 1 : 0),
                             (long) ((flags & DUK__IVAL_FLAG_REQUIRE_SHORT) ? 1 : 0)));

        /* first coerce to a plain value */
        duk__ivalue_toplain_raw(comp_ctx, x, forced_reg);
        DUK_ASSERT(x->t == DUK_IVAL_PLAIN);

        /* then to a register */
        reg = duk__ispec_toregconst_raw(comp_ctx, &x->x1, forced_reg, flags);
        x->x1.t = DUK_ISPEC_REGCONST;
        x->x1.regconst = reg;

        return reg;
}

DUK_LOCAL duk_reg_t duk__ivalue_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
        return duk__ivalue_toregconst_raw(comp_ctx, x, -1, 0 /*flags*/);
}

#if 0  /* unused */
DUK_LOCAL duk_reg_t duk__ivalue_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
        return duk__ivalue_toregconst_raw(comp_ctx, x, -1, DUK__IVAL_FLAG_REQUIRE_TEMP /*flags*/);
}
#endif

DUK_LOCAL void duk__ivalue_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *x, duk_int_t forced_reg) {
        DUK_ASSERT(forced_reg >= 0);
        (void) duk__ivalue_toregconst_raw(comp_ctx, x, forced_reg, 0 /*flags*/);
}

DUK_LOCAL duk_regconst_t duk__ivalue_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
        return duk__ivalue_toregconst_raw(comp_ctx, x, -1, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
}

DUK_LOCAL duk_regconst_t duk__ivalue_totempconst(duk_compiler_ctx *comp_ctx, duk_ivalue *x) {
        return duk__ivalue_toregconst_raw(comp_ctx, x, -1, DUK__IVAL_FLAG_ALLOW_CONST | DUK__IVAL_FLAG_REQUIRE_TEMP /*flags*/);
}

/* The issues below can be solved with better flags */

/* XXX: many operations actually want toforcedtemp() -- brand new temp? */
/* XXX: need a toplain_ignore() which will only coerce a value to a temp
 * register if it might have a side effect.  Side-effect free values do not
 * need to be coerced.
 */

/*
 *  Identifier handling
 */

DUK_LOCAL duk_reg_t duk__lookup_active_register_binding(duk_compiler_ctx *comp_ctx) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_hstring *h_varname;
        duk_reg_t ret;

        DUK_DDD(DUK_DDDPRINT("resolving identifier reference to '%!T'",
                             (duk_tval *) duk_get_tval(ctx, -1)));

        /*
         *  Special name handling
         */

        h_varname = duk_get_hstring(ctx, -1);
        DUK_ASSERT(h_varname != NULL);

        if (h_varname == DUK_HTHREAD_STRING_LC_ARGUMENTS(thr)) {
                DUK_DDD(DUK_DDDPRINT("flagging function as accessing 'arguments'"));
                comp_ctx->curr_func.id_access_arguments = 1;
        }

        /*
         *  Inside one or more 'with' statements fall back to slow path always.
         *  (See e.g. test-stmt-with.js.)
         */

        if (comp_ctx->curr_func.with_depth > 0) {
                DUK_DDD(DUK_DDDPRINT("identifier lookup inside a 'with' -> fall back to slow path"));
                goto slow_path;
        }

        /*
         *  Any catch bindings ("catch (e)") also affect identifier binding.
         *
         *  Currently, the varmap is modified for the duration of the catch
         *  clause to ensure any identifier accesses with the catch variable
         *  name will use slow path.
         */

        duk_get_prop(ctx, comp_ctx->curr_func.varmap_idx);
        if (duk_is_number(ctx, -1)) {
                ret = duk_to_int(ctx, -1);
                duk_pop(ctx);
        } else {
                duk_pop(ctx);
                goto slow_path;
        }

        DUK_DDD(DUK_DDDPRINT("identifier lookup -> reg %ld", (long) ret));
        return ret;

 slow_path:
        DUK_DDD(DUK_DDDPRINT("identifier lookup -> slow path"));

        comp_ctx->curr_func.id_access_slow = 1;
        return (duk_reg_t) -1;
}

/* Lookup an identifier name in the current varmap, indicating whether the
 * identifier is register-bound and if not, allocating a constant for the
 * identifier name.  Returns 1 if register-bound, 0 otherwise.  Caller can
 * also check (out_reg_varbind >= 0) to check whether or not identifier is
 * register bound.  The caller must NOT use out_rc_varname at all unless
 * return code is 0 or out_reg_varbind is < 0; this is becuase out_rc_varname
 * is unsigned and doesn't have a "unused" / none value.
 */
DUK_LOCAL duk_bool_t duk__lookup_lhs(duk_compiler_ctx *comp_ctx, duk_reg_t *out_reg_varbind, duk_regconst_t *out_rc_varname) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_reg_t reg_varbind;
        duk_regconst_t rc_varname;

        /* [ ... varname ] */

        duk_dup_top(ctx);
        reg_varbind = duk__lookup_active_register_binding(comp_ctx);

        if (reg_varbind >= 0) {
                *out_reg_varbind = reg_varbind;
                *out_rc_varname = 0;  /* duk_regconst_t is unsigned, so use 0 as dummy value (ignored by caller) */
                duk_pop(ctx);
                return 1;
        } else {
                rc_varname = duk__getconst(comp_ctx);
                *out_reg_varbind = -1;
                *out_rc_varname = rc_varname;
                return 0;
        }
}

/*
 *  Label handling
 *
 *  Labels are initially added with flags prohibiting both break and continue.
 *  When the statement type is finally uncovered (after potentially multiple
 *  labels), all the labels are updated to allow/prohibit break and continue.
 */

DUK_LOCAL void duk__add_label(duk_compiler_ctx *comp_ctx, duk_hstring *h_label, duk_int_t pc_label, duk_int_t label_id) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_size_t n;
        duk_size_t new_size;
        duk_uint8_t *p;
        duk_labelinfo *li_start, *li;

        /* Duplicate (shadowing) labels are not allowed, except for the empty
         * labels (which are used as default labels for switch and iteration
         * statements).
         *
         * We could also allow shadowing of non-empty pending labels without any
         * other issues than breaking the required label shadowing requirements
         * of the E5 specification, see Section 12.12.
         */

        p = (duk_uint8_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, comp_ctx->curr_func.h_labelinfos);
        li_start = (duk_labelinfo *) (void *) p;
        li = (duk_labelinfo *) (void *) (p + DUK_HBUFFER_GET_SIZE(comp_ctx->curr_func.h_labelinfos));
        n = (duk_size_t) (li - li_start);

        while (li > li_start) {
                li--;

                if (li->h_label == h_label && h_label != DUK_HTHREAD_STRING_EMPTY_STRING(thr)) {
                        DUK_ERROR_SYNTAX(thr, DUK_STR_DUPLICATE_LABEL);
                }
        }

        duk_push_hstring(ctx, h_label);
        DUK_ASSERT(n <= DUK_UARRIDX_MAX);  /* label limits */
        (void) duk_put_prop_index(ctx, comp_ctx->curr_func.labelnames_idx, (duk_uarridx_t) n);

        new_size = (n + 1) * sizeof(duk_labelinfo);
        duk_hbuffer_resize(thr, comp_ctx->curr_func.h_labelinfos, new_size);
        /* XXX: spare handling, slow now */

        /* relookup after possible realloc */
        p = (duk_uint8_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, comp_ctx->curr_func.h_labelinfos);
        li_start = (duk_labelinfo *) (void *) p;
        DUK_UNREF(li_start);  /* silence scan-build warning */
        li = (duk_labelinfo *) (void *) (p + DUK_HBUFFER_GET_SIZE(comp_ctx->curr_func.h_labelinfos));
        li--;

        /* Labels can be used for iteration statements but also for other statements,
         * in particular a label can be used for a block statement.  All cases of a
         * named label accept a 'break' so that flag is set here.  Iteration statements
         * also allow 'continue', so that flag is updated when we figure out the
         * statement type.
         */

        li->flags = DUK_LABEL_FLAG_ALLOW_BREAK;
        li->label_id = label_id;
        li->h_label = h_label;
        li->catch_depth = comp_ctx->curr_func.catch_depth;   /* catch depth from current func */
        li->pc_label = pc_label;

        DUK_DDD(DUK_DDDPRINT("registered label: flags=0x%08lx, id=%ld, name=%!O, catch_depth=%ld, pc_label=%ld",
                             (unsigned long) li->flags, (long) li->label_id, (duk_heaphdr *) li->h_label,
                             (long) li->catch_depth, (long) li->pc_label));
}

/* Update all labels with matching label_id. */
DUK_LOCAL void duk__update_label_flags(duk_compiler_ctx *comp_ctx, duk_int_t label_id, duk_small_uint_t flags) {
        duk_uint8_t *p;
        duk_labelinfo *li_start, *li;

        p = (duk_uint8_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(comp_ctx->thr->heap, comp_ctx->curr_func.h_labelinfos);
        li_start = (duk_labelinfo *) (void *) p;
        li = (duk_labelinfo *) (void *) (p + DUK_HBUFFER_GET_SIZE(comp_ctx->curr_func.h_labelinfos));

        /* Match labels starting from latest; once label_id no longer matches, we can
         * safely exit without checking the rest of the labels (only the topmost labels
         * are ever updated).
         */
        while (li > li_start) {
                li--;

                if (li->label_id != label_id) {
                        break;
                }

                DUK_DDD(DUK_DDDPRINT("updating (overwriting) label flags for li=%p, label_id=%ld, flags=%ld",
                                     (void *) li, (long) label_id, (long) flags));

                li->flags = flags;
        }
}

/* Lookup active label information.  Break/continue distinction is necessary to handle switch
 * statement related labels correctly: a switch will only catch a 'break', not a 'continue'.
 *
 * An explicit label cannot appear multiple times in the active set, but empty labels (unlabelled
 * iteration and switch statements) can.  A break will match the closest unlabelled or labelled
 * statement.  A continue will match the closest unlabelled or labelled iteration statement.  It is
 * a syntax error if a continue matches a labelled switch statement; because an explicit label cannot
 * be duplicated, the continue cannot match any valid label outside the switch.
 *
 * A side effect of these rules is that a LABEL statement related to a switch should never actually
 * catch a continue abrupt completion at run-time.  Hence an INVALID opcode can be placed in the
 * continue slot of the switch's LABEL statement.
 */

/* XXX: awkward, especially the bunch of separate output values -> output struct? */
DUK_LOCAL void duk__lookup_active_label(duk_compiler_ctx *comp_ctx, duk_hstring *h_label, duk_bool_t is_break, duk_int_t *out_label_id, duk_int_t *out_label_catch_depth, duk_int_t *out_label_pc, duk_bool_t *out_is_closest) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_uint8_t *p;
        duk_labelinfo *li_start, *li_end, *li;
        duk_bool_t match = 0;

        DUK_DDD(DUK_DDDPRINT("looking up active label: label='%!O', is_break=%ld",
                             (duk_heaphdr *) h_label, (long) is_break));

        DUK_UNREF(ctx);

        p = (duk_uint8_t *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(thr->heap, comp_ctx->curr_func.h_labelinfos);
        li_start = (duk_labelinfo *) (void *) p;
        li_end = (duk_labelinfo *) (void *) (p + DUK_HBUFFER_GET_SIZE(comp_ctx->curr_func.h_labelinfos));
        li = li_end;

        /* Match labels starting from latest label because there can be duplicate empty
         * labels in the label set.
         */
        while (li > li_start) {
                li--;

                if (li->h_label != h_label) {
                        DUK_DDD(DUK_DDDPRINT("labelinfo[%ld] ->'%!O' != %!O",
                                             (long) (li - li_start),
                                             (duk_heaphdr *) li->h_label,
                                             (duk_heaphdr *) h_label));
                        continue;
                }

                DUK_DDD(DUK_DDDPRINT("labelinfo[%ld] -> '%!O' label name matches (still need to check type)",
                                     (long) (li - li_start), (duk_heaphdr *) h_label));

                /* currently all labels accept a break, so no explicit check for it now */
                DUK_ASSERT(li->flags & DUK_LABEL_FLAG_ALLOW_BREAK);

                if (is_break) {
                        /* break matches always */
                        match = 1;
                        break;
                } else if (li->flags & DUK_LABEL_FLAG_ALLOW_CONTINUE) {
                        /* iteration statements allow continue */
                        match = 1;
                        break;
                } else {
                        /* continue matched this label -- we can only continue if this is the empty
                         * label, for which duplication is allowed, and thus there is hope of
                         * finding a match deeper in the label stack.
                         */
                        if (h_label != DUK_HTHREAD_STRING_EMPTY_STRING(thr)) {
                                DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_LABEL);
                        } else {
                                DUK_DDD(DUK_DDDPRINT("continue matched an empty label which does not "
                                                     "allow a continue -> continue lookup deeper in label stack"));
                        }
                }
        }
        /* XXX: match flag is awkward, rework */
        if (!match) {
                DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_LABEL);
        }

        DUK_DDD(DUK_DDDPRINT("label match: %!O -> label_id %ld, catch_depth=%ld, pc_label=%ld",
                             (duk_heaphdr *) h_label, (long) li->label_id,
                             (long) li->catch_depth, (long) li->pc_label));

        *out_label_id = li->label_id;
        *out_label_catch_depth = li->catch_depth;
        *out_label_pc = li->pc_label;
        *out_is_closest = (li == li_end - 1);
}

DUK_LOCAL void duk__reset_labels_to_length(duk_compiler_ctx *comp_ctx, duk_int_t len) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_size_t new_size;

        /* XXX: duk_set_length */
        new_size = sizeof(duk_labelinfo) * (duk_size_t) len;
        duk_push_int(ctx, len);
        duk_put_prop_stridx(ctx, comp_ctx->curr_func.labelnames_idx, DUK_STRIDX_LENGTH);
        duk_hbuffer_resize(thr, comp_ctx->curr_func.h_labelinfos, new_size);
}

/*
 *  Expression parsing: duk__expr_nud(), duk__expr_led(), duk__expr_lbp(), and helpers.
 *
 *  - duk__expr_nud(): ("null denotation"): process prev_token as a "start" of an expression (e.g. literal)
 *  - duk__expr_led(): ("left denotation"): process prev_token in the "middle" of an expression (e.g. operator)
 *  - duk__expr_lbp(): ("left-binding power"): return left-binding power of curr_token
 */

/* object literal key tracking flags */
#define DUK__OBJ_LIT_KEY_PLAIN  (1 << 0)  /* key encountered as a plain property */
#define DUK__OBJ_LIT_KEY_GET    (1 << 1)  /* key encountered as a getter */
#define DUK__OBJ_LIT_KEY_SET    (1 << 2)  /* key encountered as a setter */

DUK_LOCAL void duk__nud_array_literal(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_hthread *thr = comp_ctx->thr;
        duk_reg_t reg_obj;                 /* result reg */
        duk_reg_t reg_temp;                /* temp reg */
        duk_reg_t temp_start;              /* temp reg value for start of loop */
        duk_small_uint_t max_init_values;  /* max # of values initialized in one MPUTARR set */
        duk_small_uint_t num_values;       /* number of values in current MPUTARR set */
        duk_uarridx_t curr_idx;            /* current (next) array index */
        duk_uarridx_t start_idx;           /* start array index of current MPUTARR set */
        duk_uarridx_t init_idx;            /* last array index explicitly initialized, +1 */
        duk_bool_t require_comma;          /* next loop requires a comma */

        /* DUK_TOK_LBRACKET already eaten, current token is right after that */
        DUK_ASSERT(comp_ctx->prev_token.t == DUK_TOK_LBRACKET);

        max_init_values = DUK__MAX_ARRAY_INIT_VALUES;  /* XXX: depend on available temps? */

        reg_obj = DUK__ALLOCTEMP(comp_ctx);
        duk__emit_extraop_b_c(comp_ctx,
                              DUK_EXTRAOP_NEWARR | DUK__EMIT_FLAG_B_IS_TARGET,
                              reg_obj,
                              0);  /* XXX: patch initial size afterwards? */
        temp_start = DUK__GETTEMP(comp_ctx);

        /*
         *  Emit initializers in sets of maximum max_init_values.
         *  Corner cases such as single value initializers do not have
         *  special handling now.
         *
         *  Elided elements must not be emitted as 'undefined' values,
         *  because such values would be enumerable (which is incorrect).
         *  Also note that trailing elisions must be reflected in the
         *  length of the final array but cause no elements to be actually
         *  inserted.
         */

        curr_idx = 0;
        init_idx = 0;         /* tracks maximum initialized index + 1 */
        start_idx = 0;
        require_comma = 0;

        for (;;) {
                num_values = 0;
                DUK__SETTEMP(comp_ctx, temp_start);

                if (comp_ctx->curr_token.t == DUK_TOK_RBRACKET) {
                        break;
                }

                for (;;) {
                        if (comp_ctx->curr_token.t == DUK_TOK_RBRACKET) {
                                /* the outer loop will recheck and exit */
                                break;
                        }

                        /* comma check */
                        if (require_comma) {
                                if (comp_ctx->curr_token.t == DUK_TOK_COMMA) {
                                        /* comma after a value, expected */
                                        duk__advance(comp_ctx);
                                        require_comma = 0;
                                        continue;
                                } else {
                                        goto syntax_error;
                                }
                        } else {
                                if (comp_ctx->curr_token.t == DUK_TOK_COMMA) {
                                        /* elision - flush */
                                        curr_idx++;
                                        duk__advance(comp_ctx);
                                        /* if num_values > 0, MPUTARR emitted by outer loop after break */
                                        break;
                                }
                        }
                        /* else an array initializer element */

                        /* initial index */
                        if (num_values == 0) {
                                start_idx = curr_idx;
                                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                                duk__emit_load_int32(comp_ctx, reg_temp, (duk_int32_t) start_idx);
                        }

                        reg_temp = DUK__ALLOCTEMP(comp_ctx);   /* alloc temp just in case, to update max temp */
                        DUK__SETTEMP(comp_ctx, reg_temp);
                        duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp /*forced_reg*/);
                        DUK__SETTEMP(comp_ctx, reg_temp + 1);

                        num_values++;
                        curr_idx++;
                        require_comma = 1;

                        if (num_values >= max_init_values) {
                                /* MPUTARR emitted by outer loop */
                                break;
                        }
                }

                if (num_values > 0) {
                        /* - A is a source register (it's not a write target, but used
                         *   to identify the target object) but can be shuffled.
                         * - B cannot be shuffled normally because it identifies a range
                         *   of registers, the emitter has special handling for this
                         *   (the "no shuffle" flag must not be set).
                         * - C is a non-register number and cannot be shuffled, but
                         *   never needs to be.
                         */
                        duk__emit_a_b_c(comp_ctx,
                                        DUK_OP_MPUTARR |
                                            DUK__EMIT_FLAG_NO_SHUFFLE_C |
                                            DUK__EMIT_FLAG_A_IS_SOURCE,
                                        (duk_regconst_t) reg_obj,
                                        (duk_regconst_t) temp_start,
                                        (duk_regconst_t) num_values);
                        init_idx = start_idx + num_values;

                        /* num_values and temp_start reset at top of outer loop */
                }
        }

        DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_RBRACKET);
        duk__advance(comp_ctx);

        DUK_DDD(DUK_DDDPRINT("array literal done, curridx=%ld, initidx=%ld",
                             (long) curr_idx, (long) init_idx));

        /* trailing elisions? */
        if (curr_idx > init_idx) {
                /* yes, must set array length explicitly */
                DUK_DDD(DUK_DDDPRINT("array literal has trailing elisions which affect its length"));
                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                duk__emit_load_int32(comp_ctx, reg_temp, (duk_int_t) curr_idx);
                duk__emit_extraop_b_c(comp_ctx,
                                      DUK_EXTRAOP_SETALEN,
                                      (duk_regconst_t) reg_obj,
                                      (duk_regconst_t) reg_temp);
        }

        DUK__SETTEMP(comp_ctx, temp_start);

        res->t = DUK_IVAL_PLAIN;
        res->x1.t = DUK_ISPEC_REGCONST;
        res->x1.regconst = (duk_regconst_t) reg_obj;
        return;

 syntax_error:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_ARRAY_LITERAL);
}

/* duplicate/invalid key checks; returns 1 if syntax error */
DUK_LOCAL duk_bool_t duk__nud_object_literal_key_check(duk_compiler_ctx *comp_ctx, duk_small_uint_t new_key_flags) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_small_uint_t key_flags;

        /* [ ... key_obj key ] */

        DUK_ASSERT(duk_is_string(ctx, -1));

        /*
         *  'key_obj' tracks keys encountered so far by associating an
         *  integer with flags with already encountered keys.  The checks
         *  below implement E5 Section 11.1.5, step 4 for production:
         *
         *    PropertyNameAndValueList: PropertyNameAndValueList , PropertyAssignment
         */

        duk_dup(ctx, -1);       /* [ ... key_obj key key ] */
        duk_get_prop(ctx, -3);  /* [ ... key_obj key val ] */
        key_flags = duk_to_int(ctx, -1);
        duk_pop(ctx);           /* [ ... key_obj key ] */

        if (new_key_flags & DUK__OBJ_LIT_KEY_PLAIN) {
                if ((key_flags & DUK__OBJ_LIT_KEY_PLAIN) && comp_ctx->curr_func.is_strict) {
                        /* step 4.a */
                        DUK_DDD(DUK_DDDPRINT("duplicate key: plain key appears twice in strict mode"));
                        return 1;
                }
                if (key_flags & (DUK__OBJ_LIT_KEY_GET | DUK__OBJ_LIT_KEY_SET)) {
                        /* step 4.c */
                        DUK_DDD(DUK_DDDPRINT("duplicate key: plain key encountered after setter/getter"));
                        return 1;
                }
        } else {
                if (key_flags & DUK__OBJ_LIT_KEY_PLAIN) {
                        /* step 4.b */
                        DUK_DDD(DUK_DDDPRINT("duplicate key: getter/setter encountered after plain key"));
                        return 1;
                }
                if (key_flags & new_key_flags) {
                        /* step 4.d */
                        DUK_DDD(DUK_DDDPRINT("duplicate key: getter/setter encountered twice"));
                        return 1;
                }
        }

        new_key_flags |= key_flags;
        DUK_DDD(DUK_DDDPRINT("setting/updating key %!T flags: 0x%08lx -> 0x%08lx",
                             (duk_tval *) duk_get_tval(ctx, -1),
                             (unsigned long) key_flags,
                             (unsigned long) new_key_flags));
        duk_dup(ctx, -1);
        duk_push_int(ctx, new_key_flags);   /* [ ... key_obj key key flags ] */
        duk_put_prop(ctx, -4);              /* [ ... key_obj key ] */

        return 0;
}

DUK_LOCAL void duk__nud_object_literal(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_reg_t reg_obj;                /* result reg */
        duk_reg_t reg_key;                /* temp reg for key literal */
        duk_reg_t reg_temp;               /* temp reg */
        duk_reg_t temp_start;             /* temp reg value for start of loop */
        duk_small_uint_t max_init_pairs;  /* max # of key-value pairs initialized in one MPUTOBJ set */
        duk_small_uint_t num_pairs;       /* number of pairs in current MPUTOBJ set */
        duk_bool_t first;                 /* first value: comma must not precede the value */
        duk_bool_t is_set, is_get;        /* temps */

        DUK_ASSERT(comp_ctx->prev_token.t == DUK_TOK_LCURLY);

        max_init_pairs = DUK__MAX_OBJECT_INIT_PAIRS;  /* XXX: depend on available temps? */

        reg_obj = DUK__ALLOCTEMP(comp_ctx);
        duk__emit_extraop_b_c(comp_ctx,
                              DUK_EXTRAOP_NEWOBJ | DUK__EMIT_FLAG_B_IS_TARGET,
                              reg_obj,
                              0);  /* XXX: patch initial size afterwards? */
        temp_start = DUK__GETTEMP(comp_ctx);

        /* temp object for tracking / detecting duplicate keys */
        duk_push_object(ctx);

        /*
         *  Emit initializers in sets of maximum max_init_pairs keys.
         *  Setter/getter is handled separately and terminates the
         *  current set of initializer values.  Corner cases such as
         *  single value initializers do not have special handling now.
         */

        first = 1;
        for (;;) {
                num_pairs = 0;
                DUK__SETTEMP(comp_ctx, temp_start);

                if (comp_ctx->curr_token.t == DUK_TOK_RCURLY) {
                        break;
                }

                for (;;) {
                        /*
                         *  Three possible element formats:
                         *    1) PropertyName : AssignmentExpression
                         *    2) get PropertyName () { FunctionBody }
                         *    3) set PropertyName ( PropertySetParameterList ) { FunctionBody }
                         *
                         *  PropertyName can be IdentifierName (includes reserved words), a string
                         *  literal, or a number literal.  Note that IdentifierName allows 'get' and
                         *  'set' too, so we need to look ahead to the next token to distinguish:
                         *
                         *     { get : 1 }
                         *
                         *  and
                         *
                         *     { get foo() { return 1 } }
                         *     { get get() { return 1 } }    // 'get' as getter propertyname
                         *
                         *  Finally, a trailing comma is allowed.
                         *
                         *  Key name is coerced to string at compile time (and ends up as a
                         *  a string constant) even for numeric keys (e.g. "{1:'foo'}").
                         *  These could be emitted using e.g. LDINT, but that seems hardly
                         *  worth the effort and would increase code size.
                         */

                        DUK_DDD(DUK_DDDPRINT("object literal inner loop, curr_token->t = %ld",
                                             (long) comp_ctx->curr_token.t));

                        if (comp_ctx->curr_token.t == DUK_TOK_RCURLY) {
                                /* the outer loop will recheck and exit */
                                break;
                        }
                        if (num_pairs >= max_init_pairs) {
                                /* MPUTOBJ emitted by outer loop */
                                break;
                        }

                        if (first) {
                                first = 0;
                        } else {
                                if (comp_ctx->curr_token.t != DUK_TOK_COMMA) {
                                        goto syntax_error;
                                }
                                duk__advance(comp_ctx);
                                if (comp_ctx->curr_token.t == DUK_TOK_RCURLY) {
                                        /* trailing comma followed by rcurly */
                                        break;
                                }
                        }

                        /* advance to get one step of lookup */
                        duk__advance(comp_ctx);

                        /* NOTE: "get" and "set" are not officially ReservedWords and the lexer
                         * currently treats them always like ordinary identifiers (DUK_TOK_GET
                         * and DUK_TOK_SET are unused).  They need to be detected based on the
                         * identifier string content.
                         */

                        is_get = (comp_ctx->prev_token.t == DUK_TOK_IDENTIFIER &&
                                  comp_ctx->prev_token.str1 == DUK_HTHREAD_STRING_GET(thr));
                        is_set = (comp_ctx->prev_token.t == DUK_TOK_IDENTIFIER &&
                                  comp_ctx->prev_token.str1 == DUK_HTHREAD_STRING_SET(thr));
                        if ((is_get || is_set) && comp_ctx->curr_token.t != DUK_TOK_COLON) {
                                /* getter/setter */
                                duk_int_t fnum;

                                if (comp_ctx->curr_token.t_nores == DUK_TOK_IDENTIFIER ||
                                    comp_ctx->curr_token.t_nores == DUK_TOK_STRING) {
                                        /* same handling for identifiers and strings */
                                        DUK_ASSERT(comp_ctx->curr_token.str1 != NULL);
                                        duk_push_hstring(ctx, comp_ctx->curr_token.str1);
                                } else if (comp_ctx->curr_token.t == DUK_TOK_NUMBER) {
                                        duk_push_number(ctx, comp_ctx->curr_token.num);
                                        duk_to_string(ctx, -1);
                                } else {
                                        goto syntax_error;
                                }

                                DUK_ASSERT(duk_is_string(ctx, -1));
                                if (duk__nud_object_literal_key_check(comp_ctx,
                                                                      (is_get ? DUK__OBJ_LIT_KEY_GET : DUK__OBJ_LIT_KEY_SET))) {
                                        goto syntax_error;
                                }
                                reg_key = duk__getconst(comp_ctx);

                                if (num_pairs > 0) {
                                        /* - A is a source register (it's not a write target, but used
                                         *   to identify the target object) but can be shuffled.
                                         * - B cannot be shuffled normally because it identifies a range
                                         *   of registers, the emitter has special handling for this
                                         *   (the "no shuffle" flag must not be set).
                                         * - C is a non-register number and cannot be shuffled, but
                                         *   never needs to be.
                                         */
                                        duk__emit_a_b_c(comp_ctx,
                                                        DUK_OP_MPUTOBJ |
                                                            DUK__EMIT_FLAG_NO_SHUFFLE_C |
                                                            DUK__EMIT_FLAG_A_IS_SOURCE,
                                                        reg_obj,
                                                        temp_start,
                                                        num_pairs);
                                        num_pairs = 0;
                                        DUK__SETTEMP(comp_ctx, temp_start);
                                }

                                /* curr_token = get/set name */
                                fnum = duk__parse_func_like_fnum(comp_ctx, 0 /*is_decl*/, 1 /*is_setget*/);

                                DUK_ASSERT(DUK__GETTEMP(comp_ctx) == temp_start);
                                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                                duk__emit_a_bc(comp_ctx,
                                               DUK_OP_LDCONST,
                                               (duk_regconst_t) reg_temp,
                                               (duk_regconst_t) reg_key);
                                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                                duk__emit_a_bc(comp_ctx,
                                               DUK_OP_CLOSURE,
                                               (duk_regconst_t) reg_temp,
                                               (duk_regconst_t) fnum);

                                /* Slot C is used in a non-standard fashion (range of regs),
                                 * emitter code has special handling for it (must not set the
                                 * "no shuffle" flag).
                                 */
                                duk__emit_extraop_b_c(comp_ctx,
                                                      (is_get ? DUK_EXTRAOP_INITGET : DUK_EXTRAOP_INITSET),
                                                      reg_obj,
                                                      temp_start);   /* temp_start+0 = key, temp_start+1 = closure */

                                DUK__SETTEMP(comp_ctx, temp_start);
                        } else {
                                /* normal key/value */
                                if (comp_ctx->prev_token.t_nores == DUK_TOK_IDENTIFIER ||
                                    comp_ctx->prev_token.t_nores == DUK_TOK_STRING) {
                                        /* same handling for identifiers and strings */
                                        DUK_ASSERT(comp_ctx->prev_token.str1 != NULL);
                                        duk_push_hstring(ctx, comp_ctx->prev_token.str1);
                                } else if (comp_ctx->prev_token.t == DUK_TOK_NUMBER) {
                                        duk_push_number(ctx, comp_ctx->prev_token.num);
                                        duk_to_string(ctx, -1);
                                } else {
                                        goto syntax_error;
                                }

                                DUK_ASSERT(duk_is_string(ctx, -1));
                                if (duk__nud_object_literal_key_check(comp_ctx, DUK__OBJ_LIT_KEY_PLAIN)) {
                                        goto syntax_error;
                                }
                                reg_key = duk__getconst(comp_ctx);

                                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                                duk__emit_a_bc(comp_ctx,
                                               DUK_OP_LDCONST,
                                               (duk_regconst_t) reg_temp,
                                               (duk_regconst_t) reg_key);
                                duk__advance_expect(comp_ctx, DUK_TOK_COLON);

                                reg_temp = DUK__ALLOCTEMP(comp_ctx);  /* alloc temp just in case, to update max temp */
                                DUK__SETTEMP(comp_ctx, reg_temp);
                                duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp /*forced_reg*/);
                                DUK__SETTEMP(comp_ctx, reg_temp + 1);

                                num_pairs++;
                        }
                }

                if (num_pairs > 0) {
                        /* See MPUTOBJ comments above. */
                        duk__emit_a_b_c(comp_ctx,
                                        DUK_OP_MPUTOBJ |
                                            DUK__EMIT_FLAG_NO_SHUFFLE_C |
                                            DUK__EMIT_FLAG_A_IS_SOURCE,
                                        reg_obj,
                                        temp_start,
                                        num_pairs);

                        /* num_pairs and temp_start reset at top of outer loop */
                }
        }

        DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_RCURLY);
        duk__advance(comp_ctx);

        DUK__SETTEMP(comp_ctx, temp_start);

        res->t = DUK_IVAL_PLAIN;
        res->x1.t = DUK_ISPEC_REGCONST;
        res->x1.regconst = (duk_regconst_t) reg_obj;

        DUK_DDD(DUK_DDDPRINT("final tracking object: %!T",
                             (duk_tval *) duk_get_tval(ctx, -1)));
        duk_pop(ctx);
        return;

 syntax_error:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_OBJECT_LITERAL);
}

/* Parse argument list.  Arguments are written to temps starting from
 * "next temp".  Returns number of arguments parsed.  Expects left paren
 * to be already eaten, and eats the right paren before returning.
 */
DUK_LOCAL duk_int_t duk__parse_arguments(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_int_t nargs = 0;
        duk_reg_t reg_temp;

        /* Note: expect that caller has already eaten the left paren */

        DUK_DDD(DUK_DDDPRINT("start parsing arguments, prev_token.t=%ld, curr_token.t=%ld",
                             (long) comp_ctx->prev_token.t, (long) comp_ctx->curr_token.t));

        for (;;) {
                if (comp_ctx->curr_token.t == DUK_TOK_RPAREN) {
                        break;
                }
                if (nargs > 0) {
                        duk__advance_expect(comp_ctx, DUK_TOK_COMMA);
                }

                /* We want the argument expression value to go to "next temp"
                 * without additional moves.  That should almost always be the
                 * case, but we double check after expression parsing.
                 *
                 * This is not the cleanest possible approach.
                 */

                reg_temp = DUK__ALLOCTEMP(comp_ctx);  /* bump up "allocated" reg count, just in case */
                DUK__SETTEMP(comp_ctx, reg_temp);

                /* binding power must be high enough to NOT allow comma expressions directly */
                duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp);  /* always allow 'in', coerce to 'tr' just in case */

                DUK__SETTEMP(comp_ctx, reg_temp + 1);
                nargs++;

                DUK_DDD(DUK_DDDPRINT("argument #%ld written into reg %ld", (long) nargs, (long) reg_temp));
        }

        /* eat the right paren */
        duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

        DUK_DDD(DUK_DDDPRINT("end parsing arguments"));

        return nargs;
}

DUK_LOCAL duk_bool_t duk__expr_is_empty(duk_compiler_ctx *comp_ctx) {
        /* empty expressions can be detected conveniently with nud/led counts */
        return (comp_ctx->curr_func.nud_count == 0) &&
               (comp_ctx->curr_func.led_count == 0);
}

DUK_LOCAL void duk__expr_nud(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_token *tk;
        duk_reg_t temp_at_entry;
        duk_small_int_t tok;
        duk_uint32_t args;  /* temp variable to pass constants and flags to shared code */

        /*
         *  ctx->prev_token     token to process with duk__expr_nud()
         *  ctx->curr_token     updated by caller
         *
         *  Note: the token in the switch below has already been eaten.
         */

        temp_at_entry = DUK__GETTEMP(comp_ctx);

        comp_ctx->curr_func.nud_count++;

        tk = &comp_ctx->prev_token;
        tok = tk->t;
        res->t = DUK_IVAL_NONE;

        DUK_DDD(DUK_DDDPRINT("duk__expr_nud(), prev_token.t=%ld, allow_in=%ld, paren_level=%ld",
                             (long) tk->t, (long) comp_ctx->curr_func.allow_in, (long) comp_ctx->curr_func.paren_level));

        switch (tok) {

        /* PRIMARY EXPRESSIONS */

        case DUK_TOK_THIS: {
                duk_reg_t reg_temp;
                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                duk__emit_extraop_bc(comp_ctx,
                                     DUK_EXTRAOP_LDTHIS,
                                     (duk_regconst_t) reg_temp);
                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_temp;
                return;
        }
        case DUK_TOK_IDENTIFIER: {
                res->t = DUK_IVAL_VAR;
                res->x1.t = DUK_ISPEC_VALUE;
                duk_push_hstring(ctx, tk->str1);
                duk_replace(ctx, res->x1.valstack_idx);
                return;
        }
        case DUK_TOK_NULL: {
                duk_push_null(ctx);
                goto plain_value;
        }
        case DUK_TOK_TRUE: {
                duk_push_true(ctx);
                goto plain_value;
        }
        case DUK_TOK_FALSE: {
                duk_push_false(ctx);
                goto plain_value;
        }
        case DUK_TOK_NUMBER: {
                duk_push_number(ctx, tk->num);
                goto plain_value;
        }
        case DUK_TOK_STRING: {
                DUK_ASSERT(tk->str1 != NULL);
                duk_push_hstring(ctx, tk->str1);
                goto plain_value;
        }
        case DUK_TOK_REGEXP: {
#ifdef DUK_USE_REGEXP_SUPPORT
                duk_reg_t reg_temp;
                duk_regconst_t rc_re_bytecode;  /* const */
                duk_regconst_t rc_re_source;    /* const */

                DUK_ASSERT(tk->str1 != NULL);
                DUK_ASSERT(tk->str2 != NULL);

                DUK_DDD(DUK_DDDPRINT("emitting regexp op, str1=%!O, str2=%!O",
                                     (duk_heaphdr *) tk->str1,
                                     (duk_heaphdr *) tk->str2));

                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                duk_push_hstring(ctx, tk->str1);
                duk_push_hstring(ctx, tk->str2);

                /* [ ... pattern flags ] */

                duk_regexp_compile(thr);

                /* [ ... escaped_source bytecode ] */

                rc_re_bytecode = duk__getconst(comp_ctx);
                rc_re_source = duk__getconst(comp_ctx);

                duk__emit_a_b_c(comp_ctx,
                                DUK_OP_REGEXP,
                                (duk_regconst_t) reg_temp /*a*/,
                                rc_re_bytecode /*b*/,
                                rc_re_source /*c*/);

                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_temp;
                return;
#else  /* DUK_USE_REGEXP_SUPPORT */
                goto syntax_error;
#endif  /* DUK_USE_REGEXP_SUPPORT */
        }
        case DUK_TOK_LBRACKET: {
                DUK_DDD(DUK_DDDPRINT("parsing array literal"));
                duk__nud_array_literal(comp_ctx, res);
                return;
        }
        case DUK_TOK_LCURLY: {
                DUK_DDD(DUK_DDDPRINT("parsing object literal"));
                duk__nud_object_literal(comp_ctx, res);
                return;
        }
        case DUK_TOK_LPAREN: {
                duk_bool_t prev_allow_in;

                comp_ctx->curr_func.paren_level++;
                prev_allow_in = comp_ctx->curr_func.allow_in;
                comp_ctx->curr_func.allow_in = 1; /* reset 'allow_in' for parenthesized expression */

                duk__expr(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);  /* Expression, terminates at a ')' */

                duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);
                comp_ctx->curr_func.allow_in = prev_allow_in;
                comp_ctx->curr_func.paren_level--;
                return;
        }

        /* MEMBER/NEW/CALL EXPRESSIONS */

        case DUK_TOK_NEW: {
                /*
                 *  Parsing an expression starting with 'new' is tricky because
                 *  there are multiple possible productions deriving from
                 *  LeftHandSideExpression which begin with 'new'.
                 *
                 *  We currently resort to one-token lookahead to distinguish the
                 *  cases.  Hopefully this is correct.  The binding power must be
                 *  such that parsing ends at an LPAREN (CallExpression) but not at
                 *  a PERIOD or LBRACKET (MemberExpression).
                 *
                 *  See doc/compiler.rst for discussion on the parsing approach,
                 *  and testcases/test-dev-new.js for a bunch of documented tests.
                 */

                duk_reg_t reg_target;
                duk_int_t nargs;

                DUK_DDD(DUK_DDDPRINT("begin parsing new expression"));

                reg_target = DUK__ALLOCTEMP(comp_ctx);
                duk__expr_toforcedreg(comp_ctx, res, DUK__BP_CALL /*rbp_flags*/, reg_target /*forced_reg*/);
                DUK__SETTEMP(comp_ctx, reg_target + 1);

                if (comp_ctx->curr_token.t == DUK_TOK_LPAREN) {
                        /* 'new' MemberExpression Arguments */
                        DUK_DDD(DUK_DDDPRINT("new expression has argument list"));
                        duk__advance(comp_ctx);
                        nargs = duk__parse_arguments(comp_ctx, res);  /* parse args starting from "next temp", reg_target + 1 */
                        /* right paren eaten */
                } else {
                        /* 'new' MemberExpression */
                        DUK_DDD(DUK_DDDPRINT("new expression has no argument list"));
                        nargs = 0;
                }

                /* Opcode slot C is used in a non-standard way, so shuffling
                 * is not allowed.
                 */
                duk__emit_a_b_c(comp_ctx,
                              DUK_OP_NEW | DUK__EMIT_FLAG_NO_SHUFFLE_A | DUK__EMIT_FLAG_NO_SHUFFLE_C,
                              0 /*unused*/,
                              reg_target /*target*/,
                              nargs /*num_args*/);

                DUK_DDD(DUK_DDDPRINT("end parsing new expression"));

                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_target;
                return;
        }

        /* FUNCTION EXPRESSIONS */

        case DUK_TOK_FUNCTION: {
                /* Function expression.  Note that any statement beginning with 'function'
                 * is handled by the statement parser as a function declaration, or a
                 * non-standard function expression/statement (or a SyntaxError).  We only
                 * handle actual function expressions (occurring inside an expression) here.
                 *
                 * O(depth^2) parse count for inner functions is handled by recording a
                 * lexer offset on the first compilation pass, so that the function can
                 * be efficiently skipped on the second pass.  This is encapsulated into
                 * duk__parse_func_like_fnum().
                 */

                duk_reg_t reg_temp;
                duk_int_t fnum;

                reg_temp = DUK__ALLOCTEMP(comp_ctx);

                /* curr_token follows 'function' */
                fnum = duk__parse_func_like_fnum(comp_ctx, 0 /*is_decl*/, 0 /*is_setget*/);
                DUK_DDD(DUK_DDDPRINT("parsed inner function -> fnum %ld", (long) fnum));

                duk__emit_a_bc(comp_ctx,
                               DUK_OP_CLOSURE,
                               (duk_regconst_t) reg_temp /*a*/,
                               (duk_regconst_t) fnum /*bc*/);

                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_temp;
                return;
        }

        /* UNARY EXPRESSIONS */

        case DUK_TOK_DELETE: {
                /* Delete semantics are a bit tricky.  The description in E5 specification
                 * is kind of confusing, because it distinguishes between resolvability of
                 * a reference (which is only known at runtime) seemingly at compile time
                 * (= SyntaxError throwing).
                 */
                duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
                if (res->t == DUK_IVAL_VAR) {
                        /* not allowed in strict mode, regardless of whether resolves;
                         * in non-strict mode DELVAR handles both non-resolving and
                         * resolving cases (the specification description is a bit confusing).
                         */

                        duk_reg_t reg_temp;
                        duk_reg_t reg_varbind;
                        duk_regconst_t rc_varname;

                        if (comp_ctx->curr_func.is_strict) {
                                DUK_ERROR_SYNTAX(thr, DUK_STR_CANNOT_DELETE_IDENTIFIER);
                        }

                        DUK__SETTEMP(comp_ctx, temp_at_entry);
                        reg_temp = DUK__ALLOCTEMP(comp_ctx);

                        duk_dup(ctx, res->x1.valstack_idx);
                        if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
                                /* register bound variables are non-configurable -> always false */
                                duk__emit_extraop_bc(comp_ctx,
                                                     DUK_EXTRAOP_LDFALSE,
                                                     (duk_regconst_t) reg_temp);
                        } else {
                                duk_dup(ctx, res->x1.valstack_idx);
                                rc_varname = duk__getconst(comp_ctx);
                                duk__emit_a_b(comp_ctx,
                                              DUK_OP_DELVAR,
                                              (duk_regconst_t) reg_temp,
                                              (duk_regconst_t) rc_varname);
                        }
                        res->t = DUK_IVAL_PLAIN;
                        res->x1.t = DUK_ISPEC_REGCONST;
                        res->x1.regconst = (duk_regconst_t) reg_temp;
                } else if (res->t == DUK_IVAL_PROP) {
                        duk_reg_t reg_temp;
                        duk_reg_t reg_obj;
                        duk_regconst_t rc_key;

                        DUK__SETTEMP(comp_ctx, temp_at_entry);
                        reg_temp = DUK__ALLOCTEMP(comp_ctx);
                        reg_obj = duk__ispec_toregconst_raw(comp_ctx, &res->x1, -1 /*forced_reg*/, 0 /*flags*/);  /* don't allow const */
                        rc_key = duk__ispec_toregconst_raw(comp_ctx, &res->x2, -1 /*forced_reg*/, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
                        duk__emit_a_b_c(comp_ctx,
                                        DUK_OP_DELPROP,
                                        (duk_regconst_t) reg_temp,
                                        (duk_regconst_t) reg_obj,
                                        rc_key);

                        res->t = DUK_IVAL_PLAIN;
                        res->x1.t = DUK_ISPEC_REGCONST;
                        res->x1.regconst = (duk_regconst_t) reg_temp;
                } else {
                        /* non-Reference deletion is always 'true', even in strict mode */
                        duk_push_true(ctx);
                        goto plain_value;
                }
                return;
        }
        case DUK_TOK_VOID: {
                duk__expr_toplain_ignore(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
                duk_push_undefined(ctx);
                goto plain_value;
        }
        case DUK_TOK_TYPEOF: {
                /* 'typeof' must handle unresolvable references without throwing
                 * a ReferenceError (E5 Section 11.4.3).  Register mapped values
                 * will never be unresolvable so special handling is only required
                 * when an identifier is a "slow path" one.
                 */
                duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */

                if (res->t == DUK_IVAL_VAR) {
                        duk_reg_t reg_varbind;
                        duk_regconst_t rc_varname;
                        duk_reg_t reg_temp;

                        duk_dup(ctx, res->x1.valstack_idx);
                        if (!duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
                                DUK_DDD(DUK_DDDPRINT("typeof for an identifier name which could not be resolved "
                                                     "at compile time, need to use special run-time handling"));
                                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                                duk__emit_extraop_b_c(comp_ctx,
                                                      DUK_EXTRAOP_TYPEOFID | DUK__EMIT_FLAG_B_IS_TARGET,
                                                      reg_temp,
                                                      rc_varname);
                                res->t = DUK_IVAL_PLAIN;
                                res->x1.t = DUK_ISPEC_REGCONST;
                                res->x1.regconst = (duk_regconst_t) reg_temp;
                                return;
                        }
                }

                args = (DUK_EXTRAOP_TYPEOF << 8) + 0;
                goto unary_extraop;
        }
        case DUK_TOK_INCREMENT: {
                args = (DUK_OP_PREINCR << 8) + 0;
                goto preincdec;
        }
        case DUK_TOK_DECREMENT: {
                args = (DUK_OP_PREDECR << 8) + 0;
                goto preincdec;
        }
        case DUK_TOK_ADD: {
                /* unary plus */
                duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
                if (res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_VALUE &&
                    duk_is_number(ctx, res->x1.valstack_idx)) {
                        /* unary plus of a number is identity */
                        ;
                        return;
                }
                args = (DUK_EXTRAOP_UNP << 8) + 0;
                goto unary_extraop;
        }
        case DUK_TOK_SUB: {
                /* unary minus */
                duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
                if (res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_VALUE &&
                    duk_is_number(ctx, res->x1.valstack_idx)) {
                        /* this optimization is important to handle negative literals
                         * (which are not directly provided by the lexical grammar)
                         */
                        duk_tval *tv_num;
                        duk_double_union du;

                        tv_num = DUK_GET_TVAL_POSIDX(ctx, res->x1.valstack_idx);
                        DUK_ASSERT(tv_num != NULL);
                        DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_num));
                        du.d = DUK_TVAL_GET_NUMBER(tv_num);
                        du.d = -du.d;
                        DUK_DBLUNION_NORMALIZE_NAN_CHECK(&du);
                        DUK_TVAL_SET_NUMBER(tv_num, du.d);
                        return;
                }
                args = (DUK_EXTRAOP_UNM << 8) + 0;
                goto unary_extraop;
        }
        case DUK_TOK_BNOT: {
                duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
                args = (DUK_EXTRAOP_BNOT << 8) + 0;
                goto unary_extraop;
        }
        case DUK_TOK_LNOT: {
                duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
                if (res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_VALUE) {
                        /* Very minimal inlining to handle common idioms '!0' and '!1',
                         * and also boolean arguments like '!false' and '!true'.
                         */
                        duk_tval *tv_val;

                        tv_val = DUK_GET_TVAL_POSIDX(ctx, res->x1.valstack_idx);
                        DUK_ASSERT(tv_val != NULL);
                        if (DUK_TVAL_IS_NUMBER(tv_val)) {
                                duk_double_t d;
                                d = DUK_TVAL_GET_NUMBER(tv_val);
                                if (d == 0.0) {
                                        /* Matches both +0 and -0 on purpose. */
                                        DUK_DDD(DUK_DDDPRINT("inlined lnot: !0 -> true"));
                                        DUK_TVAL_SET_BOOLEAN_TRUE(tv_val);
                                        return;
                                } else if (d == 1.0) {
                                        DUK_DDD(DUK_DDDPRINT("inlined lnot: !1 -> false"));
                                        DUK_TVAL_SET_BOOLEAN_FALSE(tv_val);
                                        return;
                                }
                        } else if (DUK_TVAL_IS_BOOLEAN(tv_val)) {
                                duk_small_int_t v;
                                v = DUK_TVAL_GET_BOOLEAN(tv_val);
                                DUK_DDD(DUK_DDDPRINT("inlined lnot boolean: %ld", (long) v));
                                DUK_ASSERT(v == 0 || v == 1);
                                DUK_TVAL_SET_BOOLEAN(tv_val, v ^ 0x01);
                                return;
                        }
                }
                args = (DUK_EXTRAOP_LNOT << 8) + 0;
                goto unary_extraop;
        }

        }  /* end switch */

        DUK_ERROR_SYNTAX(thr, DUK_STR_PARSE_ERROR);
        return;

 unary_extraop:
        {
                /* Note: must coerce to a (writable) temp register, so that e.g. "!x" where x
                 * is a reg-mapped variable works correctly (does not mutate the variable register).
                 */

                duk_reg_t reg_temp;
                reg_temp = duk__ivalue_toregconst_raw(comp_ctx, res, -1 /*forced_reg*/, DUK__IVAL_FLAG_REQUIRE_TEMP /*flags*/);
                duk__emit_extraop_bc(comp_ctx,
                                     (args >> 8),
                                     (duk_regconst_t) reg_temp);
                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_temp;
                return;
        }

 preincdec:
        {
                /* preincrement and predecrement */
                duk_reg_t reg_res;
                duk_small_uint_t args_op = args >> 8;

                /* Specific assumptions for opcode numbering. */
                DUK_ASSERT(DUK_OP_PREINCR + 4 == DUK_OP_PREINCV);
                DUK_ASSERT(DUK_OP_PREDECR + 4 == DUK_OP_PREDECV);
                DUK_ASSERT(DUK_OP_PREINCR + 8 == DUK_OP_PREINCP);
                DUK_ASSERT(DUK_OP_PREDECR + 8 == DUK_OP_PREDECP);

                reg_res = DUK__ALLOCTEMP(comp_ctx);

                duk__expr(comp_ctx, res, DUK__BP_MULTIPLICATIVE /*rbp_flags*/);  /* UnaryExpression */
                if (res->t == DUK_IVAL_VAR) {
                        duk_hstring *h_varname;
                        duk_reg_t reg_varbind;
                        duk_regconst_t rc_varname;

                        h_varname = duk_get_hstring(ctx, res->x1.valstack_idx);
                        DUK_ASSERT(h_varname != NULL);

                        if (duk__hstring_is_eval_or_arguments_in_strict_mode(comp_ctx, h_varname)) {
                                goto syntax_error;
                        }

                        duk_dup(ctx, res->x1.valstack_idx);
                        if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
                                duk__emit_a_bc(comp_ctx,
                                               args_op,  /* e.g. DUK_OP_PREINCR */
                                               (duk_regconst_t) reg_res,
                                               (duk_regconst_t) reg_varbind);
                        } else {
                                duk__emit_a_bc(comp_ctx,
                                                args_op + 4,  /* e.g. DUK_OP_PREINCV */
                                                (duk_regconst_t) reg_res,
                                                rc_varname);
                        }

                        DUK_DDD(DUK_DDDPRINT("preincdec to '%!O' -> reg_varbind=%ld, rc_varname=%ld",
                                             (duk_heaphdr *) h_varname, (long) reg_varbind, (long) rc_varname));
                } else if (res->t == DUK_IVAL_PROP) {
                        duk_reg_t reg_obj;  /* allocate to reg only (not const) */
                        duk_regconst_t rc_key;
                        reg_obj = duk__ispec_toregconst_raw(comp_ctx, &res->x1, -1 /*forced_reg*/, 0 /*flags*/);  /* don't allow const */
                        rc_key = duk__ispec_toregconst_raw(comp_ctx, &res->x2, -1 /*forced_reg*/, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
                        duk__emit_a_b_c(comp_ctx,
                                        args_op + 8,  /* e.g. DUK_OP_PREINCP */
                                        (duk_regconst_t) reg_res,
                                        (duk_regconst_t) reg_obj,
                                        rc_key);
                } else {
                        /* Technically return value is not needed because INVLHS will
                         * unconditially throw a ReferenceError.  Coercion is necessary
                         * for proper semantics (consider ToNumber() called for an object).
                         * Use DUK_EXTRAOP_UNP with a dummy register to get ToNumber().
                         */

                        duk__ivalue_toforcedreg(comp_ctx, res, reg_res);
                        duk__emit_extraop_bc(comp_ctx,
                                             DUK_EXTRAOP_UNP,
                                             reg_res);  /* for side effects, result ignored */
                        duk__emit_extraop_only(comp_ctx,
                                               DUK_EXTRAOP_INVLHS);
                }
                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_res;
                DUK__SETTEMP(comp_ctx, reg_res + 1);
                return;
        }

 plain_value:
        {
                /* Stack top contains plain value */
                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_VALUE;
                duk_replace(ctx, res->x1.valstack_idx);
                return;
        }

 syntax_error:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_EXPRESSION);
}

/* XXX: add flag to indicate whether caller cares about return value; this
 * affects e.g. handling of assignment expressions.  This change needs API
 * changes elsewhere too.
 */
DUK_LOCAL void duk__expr_led(duk_compiler_ctx *comp_ctx, duk_ivalue *left, duk_ivalue *res) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_token *tk;
        duk_small_int_t tok;
        duk_uint32_t args;  /* temp variable to pass constants and flags to shared code */

        /*
         *  ctx->prev_token     token to process with duk__expr_led()
         *  ctx->curr_token     updated by caller
         */

        comp_ctx->curr_func.led_count++;

        /* The token in the switch has already been eaten here */
        tk = &comp_ctx->prev_token;
        tok = tk->t;

        DUK_DDD(DUK_DDDPRINT("duk__expr_led(), prev_token.t=%ld, allow_in=%ld, paren_level=%ld",
                             (long) tk->t, (long) comp_ctx->curr_func.allow_in, (long) comp_ctx->curr_func.paren_level));

        /* XXX: default priority for infix operators is duk__expr_lbp(tok) -> get it here? */

        switch (tok) {

        /* PRIMARY EXPRESSIONS */

        case DUK_TOK_PERIOD: {
                /* Property access expressions are critical for correct LHS ordering,
                 * see comments in duk__expr()!
                 *
                 * A conservative approach would be to use duk__ivalue_totempconst()
                 * for 'left'.  However, allowing a reg-bound variable seems safe here
                 * and is nice because "foo.bar" is a common expression.  If the ivalue
                 * is used in an expression a GETPROP will occur before any changes to
                 * the base value can occur.  If the ivalue is used as an assignment
                 * LHS, the assignment code will ensure the base value is safe from
                 * RHS mutation.
                 */

                /* XXX: This now coerces an identifier into a GETVAR to a temp, which
                 * causes an extra LDREG in call setup.  It's sufficient to coerce to a
                 * unary ivalue?
                 */
                duk__ivalue_toplain(comp_ctx, left);

                /* NB: must accept reserved words as property name */
                if (comp_ctx->curr_token.t_nores != DUK_TOK_IDENTIFIER) {
                        DUK_ERROR_SYNTAX(thr, DUK_STR_EXPECTED_IDENTIFIER);
                }

                res->t = DUK_IVAL_PROP;
                duk__copy_ispec(comp_ctx, &left->x1, &res->x1);  /* left.x1 -> res.x1 */
                DUK_ASSERT(comp_ctx->curr_token.str1 != NULL);
                duk_push_hstring(ctx, comp_ctx->curr_token.str1);
                duk_replace(ctx, res->x2.valstack_idx);
                res->x2.t = DUK_ISPEC_VALUE;

                /* special RegExp literal handling after IdentifierName */
                comp_ctx->curr_func.reject_regexp_in_adv = 1;

                duk__advance(comp_ctx);
                return;
        }
        case DUK_TOK_LBRACKET: {
                /* Property access expressions are critical for correct LHS ordering,
                 * see comments in duk__expr()!
                 */

                /* XXX: optimize temp reg use */
                /* XXX: similar coercion issue as in DUK_TOK_PERIOD */
                /* XXX: coerce to regs? it might be better for enumeration use, where the
                 * same PROP ivalue is used multiple times.  Or perhaps coerce PROP further
                 * there?
                 */
                /* XXX: for simple cases like x['y'] an unnecessary LDREG is
                 * emitted for the base value; could avoid it if we knew that
                 * the key expression is safe (e.g. just a single literal).
                 */

                /* The 'left' value must not be a register bound variable
                 * because it may be mutated during the rest of the expression
                 * and E5.1 Section 11.2.1 specifies the order of evaluation
                 * so that the base value is evaluated first.
                 * See: test-bug-nested-prop-mutate.js.
                 */
                duk__ivalue_totempconst(comp_ctx, left);
                duk__expr_toplain(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);  /* Expression, ']' terminates */
                duk__advance_expect(comp_ctx, DUK_TOK_RBRACKET);

                res->t = DUK_IVAL_PROP;
                duk__copy_ispec(comp_ctx, &res->x1, &res->x2);   /* res.x1 -> res.x2 */
                duk__copy_ispec(comp_ctx, &left->x1, &res->x1);  /* left.x1 -> res.x1 */
                return;
        }
        case DUK_TOK_LPAREN: {
                /* function call */
                duk_reg_t reg_cs = DUK__ALLOCTEMPS(comp_ctx, 2);
                duk_int_t nargs;
                duk_small_uint_t call_flags = 0;

                /*
                 *  XXX: attempt to get the call result to "next temp" whenever
                 *  possible to avoid unnecessary register shuffles.
                 *
                 *  XXX: CSPROP (and CSREG) can overwrite the call target register, and save one temp,
                 *  if the call target is a temporary register and at the top of the temp reg "stack".
                 */

                /*
                 *  Setup call: target and 'this' binding.  Three cases:
                 *
                 *    1. Identifier base (e.g. "foo()")
                 *    2. Property base (e.g. "foo.bar()")
                 *    3. Register base (e.g. "foo()()"; i.e. when a return value is a function)
                 */

                if (left->t == DUK_IVAL_VAR) {
                        duk_hstring *h_varname;
                        duk_reg_t reg_varbind;
                        duk_regconst_t rc_varname;

                        DUK_DDD(DUK_DDDPRINT("function call with identifier base"));

                        h_varname = duk_get_hstring(ctx, left->x1.valstack_idx);
                        DUK_ASSERT(h_varname != NULL);
                        if (h_varname == DUK_HTHREAD_STRING_EVAL(thr)) {
                                /* Potential direct eval call detected, flag the CALL
                                 * so that a run-time "direct eval" check is made and
                                 * special behavior may be triggered.  Note that this
                                 * does not prevent 'eval' from being register bound.
                                 */
                                DUK_DDD(DUK_DDDPRINT("function call with identifier 'eval' "
                                                     "-> enabling EVALCALL flag, marking function "
                                                     "as may_direct_eval"));
                                call_flags |= DUK_BC_CALL_FLAG_EVALCALL;

                                comp_ctx->curr_func.may_direct_eval = 1;
                        }

                        duk_dup(ctx, left->x1.valstack_idx);
                        if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
                                duk__emit_a_b(comp_ctx,
                                              DUK_OP_CSREG,
                                              (duk_regconst_t) (reg_cs + 0),
                                              (duk_regconst_t) reg_varbind);
                        } else {
                                duk__emit_a_b(comp_ctx,
                                              DUK_OP_CSVAR,
                                              (duk_regconst_t) (reg_cs + 0),
                                              rc_varname);
                        }
                } else if (left->t == DUK_IVAL_PROP) {
                        DUK_DDD(DUK_DDDPRINT("function call with property base"));

                        duk__ispec_toforcedreg(comp_ctx, &left->x1, reg_cs + 0);  /* base */
                        duk__ispec_toforcedreg(comp_ctx, &left->x2, reg_cs + 1);  /* key */
                        duk__emit_a_b_c(comp_ctx,
                                        DUK_OP_CSPROP,
                                        (duk_regconst_t) (reg_cs + 0),
                                        (duk_regconst_t) (reg_cs + 0),
                                        (duk_regconst_t) (reg_cs + 1));  /* in-place setup */
                } else {
                        DUK_DDD(DUK_DDDPRINT("function call with register base"));

                        duk__ivalue_toforcedreg(comp_ctx, left, reg_cs + 0);
                        duk__emit_a_b(comp_ctx,
                                      DUK_OP_CSREG,
                                      (duk_regconst_t) (reg_cs + 0),
                                      (duk_regconst_t) (reg_cs + 0));  /* in-place setup */
                }

                DUK__SETTEMP(comp_ctx, reg_cs + 2);
                nargs = duk__parse_arguments(comp_ctx, res);  /* parse args starting from "next temp" */

                /* Tailcalls are handled by back-patching the TAILCALL flag to the
                 * already emitted instruction later (in return statement parser).
                 * Since A and C have a special meaning here, they cannot be "shuffled".
                 */

                duk__emit_a_b_c(comp_ctx,
                                DUK_OP_CALL | DUK__EMIT_FLAG_NO_SHUFFLE_A | DUK__EMIT_FLAG_NO_SHUFFLE_C,
                                (duk_regconst_t) call_flags /*flags*/,
                                (duk_regconst_t) reg_cs /*basereg*/,
                                (duk_regconst_t) nargs /*numargs*/);
                DUK__SETTEMP(comp_ctx, reg_cs + 1);    /* result in csreg */

                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_cs;
                return;
        }

        /* POSTFIX EXPRESSION */

        case DUK_TOK_INCREMENT: {
                args = (DUK_OP_POSTINCR << 8) + 0;
                goto postincdec;
        }
        case DUK_TOK_DECREMENT: {
                args = (DUK_OP_POSTDECR << 8) + 0;
                goto postincdec;
        }

        /* MULTIPLICATIVE EXPRESSION */

        case DUK_TOK_MUL: {
                args = (DUK_OP_MUL << 8) + DUK__BP_MULTIPLICATIVE;  /* UnaryExpression */
                goto binary;
        }
        case DUK_TOK_DIV: {
                args = (DUK_OP_DIV << 8) + DUK__BP_MULTIPLICATIVE;  /* UnaryExpression */
                goto binary;
        }
        case DUK_TOK_MOD: {
                args = (DUK_OP_MOD << 8) + DUK__BP_MULTIPLICATIVE;  /* UnaryExpression */
                goto binary;
        }

        /* ADDITIVE EXPRESSION */

        case DUK_TOK_ADD: {
                args = (DUK_OP_ADD << 8) + DUK__BP_ADDITIVE;  /* MultiplicativeExpression */
                goto binary;
        }
        case DUK_TOK_SUB: {
                args = (DUK_OP_SUB << 8) + DUK__BP_ADDITIVE;  /* MultiplicativeExpression */
                goto binary;
        }

        /* SHIFT EXPRESSION */

        case DUK_TOK_ALSHIFT: {
                /* << */
                args = (DUK_OP_BASL << 8) + DUK__BP_SHIFT;
                goto binary;
        }
        case DUK_TOK_ARSHIFT: {
                /* >> */
                args = (DUK_OP_BASR << 8) + DUK__BP_SHIFT;
                goto binary;
        }
        case DUK_TOK_RSHIFT: {
                /* >>> */
                args = (DUK_OP_BLSR << 8) + DUK__BP_SHIFT;
                goto binary;
        }

        /* RELATIONAL EXPRESSION */

        case DUK_TOK_LT: {
                /* < */
                args = (DUK_OP_LT << 8) + DUK__BP_RELATIONAL;
                goto binary;
        }
        case DUK_TOK_GT: {
                args = (DUK_OP_GT << 8) + DUK__BP_RELATIONAL;
                goto binary;
        }
        case DUK_TOK_LE: {
                args = (DUK_OP_LE << 8) + DUK__BP_RELATIONAL;
                goto binary;
        }
        case DUK_TOK_GE: {
                args = (DUK_OP_GE << 8) + DUK__BP_RELATIONAL;
                goto binary;
        }
        case DUK_TOK_INSTANCEOF: {
                args = (1 << 16 /*is_extra*/) + (DUK_EXTRAOP_INSTOF << 8) + DUK__BP_RELATIONAL;
                goto binary;
        }
        case DUK_TOK_IN: {
                args = (1 << 16 /*is_extra*/) + (DUK_EXTRAOP_IN << 8) + DUK__BP_RELATIONAL;
                goto binary;
        }

        /* EQUALITY EXPRESSION */

        case DUK_TOK_EQ: {
                args = (DUK_OP_EQ << 8) + DUK__BP_EQUALITY;
                goto binary;
        }
        case DUK_TOK_NEQ: {
                args = (DUK_OP_NEQ << 8) + DUK__BP_EQUALITY;
                goto binary;
        }
        case DUK_TOK_SEQ: {
                args = (DUK_OP_SEQ << 8) + DUK__BP_EQUALITY;
                goto binary;
        }
        case DUK_TOK_SNEQ: {
                args = (DUK_OP_SNEQ << 8) + DUK__BP_EQUALITY;
                goto binary;
        }

        /* BITWISE EXPRESSIONS */

        case DUK_TOK_BAND: {
                args = (DUK_OP_BAND << 8) + DUK__BP_BAND;
                goto binary;
        }
        case DUK_TOK_BXOR: {
                args = (DUK_OP_BXOR << 8) + DUK__BP_BXOR;
                goto binary;
        }
        case DUK_TOK_BOR: {
                args = (DUK_OP_BOR << 8) + DUK__BP_BOR;
                goto binary;
        }

        /* LOGICAL EXPRESSIONS */

        case DUK_TOK_LAND: {
                /* syntactically left-associative but parsed as right-associative */
                args = (1 << 8) + DUK__BP_LAND - 1;
                goto binary_logical;
        }
        case DUK_TOK_LOR: {
                /* syntactically left-associative but parsed as right-associative */
                args = (0 << 8) + DUK__BP_LOR - 1;
                goto binary_logical;
        }

        /* CONDITIONAL EXPRESSION */

        case DUK_TOK_QUESTION: {
                /* XXX: common reg allocation need is to reuse a sub-expression's temp reg,
                 * but only if it really is a temp.  Nothing fancy here now.
                 */
                duk_reg_t reg_temp;
                duk_int_t pc_jump1;
                duk_int_t pc_jump2;

                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                duk__ivalue_toforcedreg(comp_ctx, left, reg_temp);
                duk__emit_if_true_skip(comp_ctx, reg_temp);
                pc_jump1 = duk__emit_jump_empty(comp_ctx);  /* jump to false */
                duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp /*forced_reg*/);  /* AssignmentExpression */
                duk__advance_expect(comp_ctx, DUK_TOK_COLON);
                pc_jump2 = duk__emit_jump_empty(comp_ctx);  /* jump to end */
                duk__patch_jump_here(comp_ctx, pc_jump1);
                duk__expr_toforcedreg(comp_ctx, res, DUK__BP_COMMA /*rbp_flags*/, reg_temp /*forced_reg*/);  /* AssignmentExpression */
                duk__patch_jump_here(comp_ctx, pc_jump2);

                DUK__SETTEMP(comp_ctx, reg_temp + 1);
                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_temp;
                return;
        }

        /* ASSIGNMENT EXPRESSION */

        case DUK_TOK_EQUALSIGN: {
                /*
                 *  Assignments are right associative, allows e.g.
                 *    a = 5;
                 *    a += b = 9;   // same as a += (b = 9)
                 *  -> expression value 14, a = 14, b = 9
                 *
                 *  Right associativiness is reflected in the BP for recursion,
                 *  "-1" ensures assignment operations are allowed.
                 *
                 *  XXX: just use DUK__BP_COMMA (i.e. no need for 2-step bp levels)?
                 */
                args = (DUK_OP_NONE << 8) + DUK__BP_ASSIGNMENT - 1;   /* DUK_OP_NONE marks a 'plain' assignment */
                goto assign;
        }
        case DUK_TOK_ADD_EQ: {
                /* right associative */
                args = (DUK_OP_ADD << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_SUB_EQ: {
                /* right associative */
                args = (DUK_OP_SUB << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_MUL_EQ: {
                /* right associative */
                args = (DUK_OP_MUL << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_DIV_EQ: {
                /* right associative */
                args = (DUK_OP_DIV << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_MOD_EQ: {
                /* right associative */
                args = (DUK_OP_MOD << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_ALSHIFT_EQ: {
                /* right associative */
                args = (DUK_OP_BASL << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_ARSHIFT_EQ: {
                /* right associative */
                args = (DUK_OP_BASR << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_RSHIFT_EQ: {
                /* right associative */
                args = (DUK_OP_BLSR << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_BAND_EQ: {
                /* right associative */
                args = (DUK_OP_BAND << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_BOR_EQ: {
                /* right associative */
                args = (DUK_OP_BOR << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }
        case DUK_TOK_BXOR_EQ: {
                /* right associative */
                args = (DUK_OP_BXOR << 8) + DUK__BP_ASSIGNMENT - 1;
                goto assign;
        }

        /* COMMA */

        case DUK_TOK_COMMA: {
                /* right associative */

                duk__ivalue_toplain_ignore(comp_ctx, left);  /* need side effects, not value */
                duk__expr_toplain(comp_ctx, res, DUK__BP_COMMA - 1 /*rbp_flags*/);

                /* return 'res' (of right part) as our result */
                return;
        }

        default: {
                break;
        }
        }

        DUK_D(DUK_DPRINT("parse error: unexpected token: %ld", (long) tok));
        DUK_ERROR_SYNTAX(thr, DUK_STR_PARSE_ERROR);
        return;

#if 0
        /* XXX: shared handling for 'duk__expr_lhs'? */
        if (comp_ctx->curr_func.paren_level == 0 && XXX) {
                comp_ctx->curr_func.duk__expr_lhs = 0;
        }
#endif

 binary:
        /*
         *  Shared handling of binary operations
         *
         *  args = (is_extraop << 16) + (opcode << 8) + rbp
         */
        {
                duk__ivalue_toplain(comp_ctx, left);
                duk__expr_toplain(comp_ctx, res, args & 0xff /*rbp_flags*/);

                /* combine left->x1 and res->x1 (right->x1, really) -> (left->x1 OP res->x1) */
                DUK_ASSERT(left->t == DUK_IVAL_PLAIN);
                DUK_ASSERT(res->t == DUK_IVAL_PLAIN);

                res->t = (args >> 16) ? DUK_IVAL_ARITH_EXTRAOP : DUK_IVAL_ARITH;
                res->op = (args >> 8) & 0xff;

                res->x2.t = res->x1.t;
                res->x2.regconst = res->x1.regconst;
                duk_copy(ctx, res->x1.valstack_idx, res->x2.valstack_idx);

                res->x1.t = left->x1.t;
                res->x1.regconst = left->x1.regconst;
                duk_copy(ctx, left->x1.valstack_idx, res->x1.valstack_idx);

                DUK_DDD(DUK_DDDPRINT("binary op, res: t=%ld, x1.t=%ld, x1.regconst=0x%08lx, x2.t=%ld, x2.regconst=0x%08lx",
                                     (long) res->t, (long) res->x1.t, (unsigned long) res->x1.regconst, (long) res->x2.t, (unsigned long) res->x2.regconst));
                return;
        }

 binary_logical:
        /*
         *  Shared handling for logical AND and logical OR.
         *
         *  args = (truthval << 8) + rbp
         *
         *  Truthval determines when to skip right-hand-side.
         *  For logical AND truthval=1, for logical OR truthval=0.
         *
         *  See doc/compiler.rst for discussion on compiling logical
         *  AND and OR expressions.  The approach here is very simplistic,
         *  generating extra jumps and multiple evaluations of truth values,
         *  but generates code on-the-fly with only local back-patching.
         *
         *  Both logical AND and OR are syntactically left-associated.
         *  However, logical ANDs are compiled as right associative
         *  expressions, i.e. "A && B && C" as "A && (B && C)", to allow
         *  skip jumps to skip over the entire tail.  Similarly for logical OR.
         */

        {
                duk_reg_t reg_temp;
                duk_int_t pc_jump;
                duk_small_uint_t args_truthval = args >> 8;
                duk_small_uint_t args_rbp = args & 0xff;

                /* XXX: unoptimal use of temps, resetting */

                reg_temp = DUK__ALLOCTEMP(comp_ctx);

                duk__ivalue_toforcedreg(comp_ctx, left, reg_temp);
                duk__emit_a_b(comp_ctx,
                              DUK_OP_IF | DUK__EMIT_FLAG_NO_SHUFFLE_A,
                              (duk_regconst_t) args_truthval,
                              (duk_regconst_t) reg_temp);  /* skip jump conditionally */
                pc_jump = duk__emit_jump_empty(comp_ctx);
                duk__expr_toforcedreg(comp_ctx, res, args_rbp /*rbp_flags*/, reg_temp /*forced_reg*/);
                duk__patch_jump_here(comp_ctx, pc_jump);

                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_temp;
                return;
        }

 assign:
        /*
         *  Shared assignment expression handling
         *
         *  args = (opcode << 8) + rbp
         *
         *  If 'opcode' is DUK_OP_NONE, plain assignment without arithmetic.
         *  Syntactically valid left-hand-side forms which are not accepted as
         *  left-hand-side values (e.g. as in "f() = 1") must NOT cause a
         *  SyntaxError, but rather a run-time ReferenceError.
         *
         *  When evaluating X <op>= Y, the LHS (X) is conceptually evaluated
         *  to a temporary first.  The RHS is then evaluated.  Finally, the
         *  <op> is applied to the initial value of RHS (not the value after
         *  RHS evaluation), and written to X.  Doing so concretely generates
         *  inefficient code so we'd like to avoid the temporary when possible.
         *  See: https://github.com/svaarala/duktape/pull/992.
         *
         *  The expression value (final LHS value, written to RHS) is
         *  conceptually copied into a fresh temporary so that it won't
         *  change even if the LHS/RHS values change in outer expressions.
         *  For example, it'd be generally incorrect for the expression value
         *  to be the RHS register binding, unless there's a guarantee that it
         *  won't change during further expression evaluation.  Using the
         *  temporary concretely produces inefficient bytecode, so we try to
         *  avoid the extra temporary for some known-to-be-safe cases.
         *  Currently the only safe case we detect is a "top level assignment",
         *  for example "x = y + z;", where the assignment expression value is
         *  ignored.
         *  See: test-dev-assign-expr.js and test-bug-assign-mutate-gh381.js.
         */

        {
                duk_small_uint_t args_op = args >> 8;
                duk_small_uint_t args_rbp = args & 0xff;
                duk_bool_t toplevel_assign;

                /* XXX: here we need to know if 'left' is left-hand-side compatible.
                 * That information is no longer available from current expr parsing
                 * state; it would need to be carried into the 'left' ivalue or by
                 * some other means.
                 */

                /* A top-level assignment is e.g. "x = y;".  For these it's safe
                 * to use the RHS as-is as the expression value, even if the RHS
                 * is a reg-bound identifier.  The RHS ('res') is right associative
                 * so it has consumed all other assignment level operations; the
                 * only relevant lower binding power construct is comma operator
                 * which will ignore the expression value provided here.  Usually
                 * the top level assignment expression value is ignored, but it
                 * is relevant for e.g. eval code.
                 */
                toplevel_assign = (comp_ctx->curr_func.nud_count == 1 && /* one token before */
                                   comp_ctx->curr_func.led_count == 1);  /* one operator (= assign) */
                DUK_DDD(DUK_DDDPRINT("assignment: nud_count=%ld, led_count=%ld, toplevel_assign=%ld",
                                     (long) comp_ctx->curr_func.nud_count,
                                     (long) comp_ctx->curr_func.led_count,
                                     (long) toplevel_assign));

                if (left->t == DUK_IVAL_VAR) {
                        duk_hstring *h_varname;
                        duk_reg_t reg_varbind;
                        duk_regconst_t rc_varname;

                        DUK_ASSERT(left->x1.t == DUK_ISPEC_VALUE);  /* LHS is already side effect free */

                        h_varname = duk_get_hstring(ctx, left->x1.valstack_idx);
                        DUK_ASSERT(h_varname != NULL);
                        if (duk__hstring_is_eval_or_arguments_in_strict_mode(comp_ctx, h_varname)) {
                                /* E5 Section 11.13.1 (and others for other assignments), step 4. */
                                goto syntax_error_lvalue;
                        }
                        duk_dup(ctx, left->x1.valstack_idx);
                        (void) duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname);

                        if (args_op == DUK_OP_NONE) {
                                duk__expr(comp_ctx, res, args_rbp /*rbp_flags*/);
                                if (toplevel_assign) {
                                        /* Any 'res' will do. */
                                        DUK_DDD(DUK_DDDPRINT("plain assignment, toplevel assign, use as is"));
                                } else {
                                        /* 'res' must be a plain ivalue, and not register-bound variable. */
                                        DUK_DDD(DUK_DDDPRINT("plain assignment, not toplevel assign, ensure not a reg-bound identifier"));
                                        if (res->t != DUK_IVAL_PLAIN || (res->x1.t == DUK_ISPEC_REGCONST &&
                                                                         (res->x1.regconst & DUK__CONST_MARKER) == 0 &&
                                                                         !DUK__ISTEMP(comp_ctx, res->x1.regconst))) {
                                                duk__ivalue_totempconst(comp_ctx, res);
                                        }
                                }
                        } else {
                                /* For X <op>= Y we need to evaluate the pre-op
                                 * value of X before evaluating the RHS: the RHS
                                 * can change X, but when we do <op> we must use
                                 * the pre-op value.
                                 */
                                duk_reg_t reg_temp;

                                reg_temp = DUK__ALLOCTEMP(comp_ctx);

                                if (reg_varbind >= 0) {
                                        duk_reg_t reg_res;
                                        duk_reg_t reg_src;
                                        duk_int_t pc_temp_load;
                                        duk_int_t pc_before_rhs;
                                        duk_int_t pc_after_rhs;

                                        if (toplevel_assign) {
                                                /* 'reg_varbind' is the operation result and can also
                                                 * become the expression value for top level assignments
                                                 * such as: "var x; x += y;".
                                                 */
                                                DUK_DD(DUK_DDPRINT("<op>= expression is top level, write directly to reg_varbind"));
                                                reg_res = reg_varbind;
                                        } else {
                                                /* Not safe to use 'reg_varbind' as assignment expression
                                                 * value, so go through a temp.
                                                 */
                                                DUK_DD(DUK_DDPRINT("<op>= expression is not top level, write to reg_temp"));
                                                reg_res = reg_temp;  /* reg_res should be smallest possible */
                                                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                                        }

                                        /* Try to optimize X <op>= Y for reg-bound
                                         * variables.  Detect side-effect free RHS
                                         * narrowly by seeing whether it emits code.
                                         * If not, rewind the code emitter and overwrite
                                         * the unnecessary temp reg load.
                                         */

                                        pc_temp_load = duk__get_current_pc(comp_ctx);
                                        duk__emit_a_bc(comp_ctx,
                                                       DUK_OP_LDREG,
                                                       (duk_regconst_t) reg_temp,
                                                       reg_varbind);

                                        pc_before_rhs = duk__get_current_pc(comp_ctx);
                                        duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);
                                        DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);
                                        pc_after_rhs = duk__get_current_pc(comp_ctx);

                                        DUK_DD(DUK_DDPRINT("pc_temp_load=%ld, pc_before_rhs=%ld, pc_after_rhs=%ld",
                                                           (long) pc_temp_load, (long) pc_before_rhs,
                                                           (long) pc_after_rhs));

                                        if (pc_after_rhs == pc_before_rhs) {
                                                /* Note: if the reg_temp load generated shuffling
                                                 * instructions, we may need to rewind more than
                                                 * one instruction, so use explicit PC computation.
                                                 */
                                                DUK_DD(DUK_DDPRINT("rhs is side effect free, rewind and avoid unnecessary temp for reg-based <op>="));
                                                DUK_BW_ADD_PTR(comp_ctx->thr, &comp_ctx->curr_func.bw_code, (pc_temp_load - pc_before_rhs) * sizeof(duk_compiler_instr));
                                                reg_src = reg_varbind;
                                        } else {
                                                DUK_DD(DUK_DDPRINT("rhs evaluation emitted code, not sure if rhs is side effect free; use temp reg for LHS"));
                                                reg_src = reg_temp;
                                        }

                                        duk__emit_a_b_c(comp_ctx,
                                                        args_op,
                                                        (duk_regconst_t) reg_res,
                                                        (duk_regconst_t) reg_src,
                                                        res->x1.regconst);

                                        res->x1.regconst = (duk_regconst_t) reg_res;

                                        /* Ensure compact use of temps. */
                                        if (DUK__ISTEMP(comp_ctx, reg_res)) {
                                                DUK__SETTEMP(comp_ctx, reg_res + 1);
                                        }
                                } else {
                                        /* When LHS is not register bound, always go through a
                                         * temporary.  No optimization for top level assignment.
                                         */

                                        duk__emit_a_bc(comp_ctx,
                                                       DUK_OP_GETVAR,
                                                       (duk_regconst_t) reg_temp,
                                                       rc_varname);

                                        duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);
                                        DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);

                                        duk__emit_a_b_c(comp_ctx,
                                                        args_op,
                                                        (duk_regconst_t) reg_temp,
                                                        (duk_regconst_t) reg_temp,
                                                        res->x1.regconst);
                                        res->x1.regconst = (duk_regconst_t) reg_temp;
                                }

                                DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);
                        }

                        /* At this point 'res' holds the potential expression value.
                         * It can be basically any ivalue here, including a reg-bound
                         * identifier (if code above deems it safe) or a unary/binary
                         * operation.  Operations must be resolved to a side effect free
                         * plain value, and the side effects must happen exactly once.
                         */

                        if (reg_varbind >= 0) {
                                if (res->t != DUK_IVAL_PLAIN) {
                                        /* Resolve 'res' directly into the LHS binding, and use
                                         * that as the expression value if safe.  If not safe,
                                         * resolve to a temp/const and copy to LHS.
                                         */
                                        if (toplevel_assign) {
                                                duk__ivalue_toforcedreg(comp_ctx, res, (duk_int_t) reg_varbind);
                                        } else {
                                                duk__ivalue_totempconst(comp_ctx, res);
                                                duk__copy_ivalue(comp_ctx, res, left);  /* use 'left' as a temp */
                                                duk__ivalue_toforcedreg(comp_ctx, left, (duk_int_t) reg_varbind);
                                        }
                                } else {
                                        /* Use 'res' as the expression value (it's side effect
                                         * free and may be a plain value, a register, or a
                                         * constant) and write it to the LHS binding too.
                                         */
                                        duk__copy_ivalue(comp_ctx, res, left);  /* use 'left' as a temp */
                                        duk__ivalue_toforcedreg(comp_ctx, left, (duk_int_t) reg_varbind);
                                }
                        } else {
                                /* Only a reg fits into 'A' so coerce 'res' into a register
                                 * for PUTVAR.
                                 *
                                 * XXX: here the current A/B/C split is suboptimal: we could
                                 * just use 9 bits for reg_res (and support constants) and 17
                                 * instead of 18 bits for the varname const index.
                                 */

                                duk__ivalue_toreg(comp_ctx, res);
                                duk__emit_a_bc(comp_ctx,
                                               DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
                                               res->x1.regconst,
                                               rc_varname);
                        }

                        /* 'res' contains expression value */
                } else if (left->t == DUK_IVAL_PROP) {
                        /* E5 Section 11.13.1 (and others) step 4 never matches for prop writes -> no check */
                        duk_reg_t reg_obj;
                        duk_regconst_t rc_key;
                        duk_regconst_t rc_res;
                        duk_reg_t reg_temp;

                        /* Property access expressions ('a[b]') are critical to correct
                         * LHS evaluation ordering, see test-dev-assign-eval-order*.js.
                         * We must make sure that the LHS target slot (base object and
                         * key) don't change during RHS evaluation.  The only concrete
                         * problem is a register reference to a variable-bound register
                         * (i.e., non-temp).  Require temp regs for both key and base.
                         *
                         * Don't allow a constant for the object (even for a number
                         * etc), as it goes into the 'A' field of the opcode.
                         */

                        reg_obj = duk__ispec_toregconst_raw(comp_ctx,
                                                            &left->x1,
                                                            -1 /*forced_reg*/,
                                                            DUK__IVAL_FLAG_REQUIRE_TEMP /*flags*/);

                        rc_key = duk__ispec_toregconst_raw(comp_ctx,
                                                           &left->x2,
                                                           -1 /*forced_reg*/,
                                                           DUK__IVAL_FLAG_REQUIRE_TEMP | DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);

                        /* Evaluate RHS only when LHS is safe. */

                        if (args_op == DUK_OP_NONE) {
                                duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);
                                DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);
                                rc_res = res->x1.regconst;
                        } else {
                                reg_temp = DUK__ALLOCTEMP(comp_ctx);
                                duk__emit_a_b_c(comp_ctx,
                                                DUK_OP_GETPROP,
                                                (duk_regconst_t) reg_temp,
                                                (duk_regconst_t) reg_obj,
                                                rc_key);

                                duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);
                                DUK_ASSERT(res->t == DUK_IVAL_PLAIN && res->x1.t == DUK_ISPEC_REGCONST);

                                duk__emit_a_b_c(comp_ctx,
                                                args_op,
                                                (duk_regconst_t) reg_temp,
                                                (duk_regconst_t) reg_temp,
                                                res->x1.regconst);
                                rc_res = (duk_regconst_t) reg_temp;
                        }

                        duk__emit_a_b_c(comp_ctx,
                                        DUK_OP_PUTPROP | DUK__EMIT_FLAG_A_IS_SOURCE,
                                        (duk_regconst_t) reg_obj,
                                        rc_key,
                                        rc_res);

                        res->t = DUK_IVAL_PLAIN;
                        res->x1.t = DUK_ISPEC_REGCONST;
                        res->x1.regconst = rc_res;
                } else {
                        /* No support for lvalues returned from new or function call expressions.
                         * However, these must NOT cause compile-time SyntaxErrors, but run-time
                         * ReferenceErrors.  Both left and right sides of the assignment must be
                         * evaluated before throwing a ReferenceError.  For instance:
                         *
                         *     f() = g();
                         *
                         * must result in f() being evaluated, then g() being evaluated, and
                         * finally, a ReferenceError being thrown.  See E5 Section 11.13.1.
                         */

                        duk_regconst_t rc_res;

                        /* First evaluate LHS fully to ensure all side effects are out. */
                        duk__ivalue_toplain_ignore(comp_ctx, left);

                        /* Then evaluate RHS fully (its value becomes the expression value too).
                         * Technically we'd need the side effect safety check here too, but because
                         * we always throw using INVLHS the result doesn't matter.
                         */
                        rc_res = duk__expr_toregconst(comp_ctx, res, args_rbp /*rbp_flags*/);

                        duk__emit_extraop_only(comp_ctx,
                                               DUK_EXTRAOP_INVLHS);

                        res->t = DUK_IVAL_PLAIN;
                        res->x1.t = DUK_ISPEC_REGCONST;
                        res->x1.regconst = rc_res;
                }

                return;
        }

 postincdec:
        {
                /*
                 *  Post-increment/decrement will return the original value as its
                 *  result value.  However, even that value will be coerced using
                 *  ToNumber() which is quite awkward.  Specific bytecode opcodes
                 *  are used to handle these semantics.
                 *
                 *  Note that post increment/decrement has a "no LineTerminator here"
                 *  restriction.  This is handled by duk__expr_lbp(), which forcibly terminates
                 *  the previous expression if a LineTerminator occurs before '++'/'--'.
                 */

                duk_reg_t reg_res;
                duk_small_uint_t args_op = args >> 8;

                /* Specific assumptions for opcode numbering. */
                DUK_ASSERT(DUK_OP_POSTINCR + 4 == DUK_OP_POSTINCV);
                DUK_ASSERT(DUK_OP_POSTDECR + 4 == DUK_OP_POSTDECV);
                DUK_ASSERT(DUK_OP_POSTINCR + 8 == DUK_OP_POSTINCP);
                DUK_ASSERT(DUK_OP_POSTDECR + 8 == DUK_OP_POSTDECP);

                reg_res = DUK__ALLOCTEMP(comp_ctx);

                if (left->t == DUK_IVAL_VAR) {
                        duk_hstring *h_varname;
                        duk_reg_t reg_varbind;
                        duk_regconst_t rc_varname;

                        h_varname = duk_get_hstring(ctx, left->x1.valstack_idx);
                        DUK_ASSERT(h_varname != NULL);

                        if (duk__hstring_is_eval_or_arguments_in_strict_mode(comp_ctx, h_varname)) {
                                goto syntax_error;
                        }

                        duk_dup(ctx, left->x1.valstack_idx);
                        if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
                                duk__emit_a_bc(comp_ctx,
                                               args_op,  /* e.g. DUK_OP_POSTINCR */
                                               (duk_regconst_t) reg_res,
                                               (duk_regconst_t) reg_varbind);
                        } else {
                                duk__emit_a_bc(comp_ctx,
                                               args_op + 4,  /* e.g. DUK_OP_POSTINCV */
                                               (duk_regconst_t) reg_res,
                                               rc_varname);
                        }

                        DUK_DDD(DUK_DDDPRINT("postincdec to '%!O' -> reg_varbind=%ld, rc_varname=%ld",
                                             (duk_heaphdr *) h_varname, (long) reg_varbind, (long) rc_varname));
                } else if (left->t == DUK_IVAL_PROP) {
                        duk_reg_t reg_obj;  /* allocate to reg only (not const) */
                        duk_regconst_t rc_key;

                        reg_obj = duk__ispec_toregconst_raw(comp_ctx, &left->x1, -1 /*forced_reg*/, 0 /*flags*/);  /* don't allow const */
                        rc_key = duk__ispec_toregconst_raw(comp_ctx, &left->x2, -1 /*forced_reg*/, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
                        duk__emit_a_b_c(comp_ctx,
                                        args_op + 8,  /* e.g. DUK_OP_POSTINCP */
                                        (duk_regconst_t) reg_res,
                                        (duk_regconst_t) reg_obj,
                                        rc_key);
                } else {
                        /* Technically return value is not needed because INVLHS will
                         * unconditially throw a ReferenceError.  Coercion is necessary
                         * for proper semantics (consider ToNumber() called for an object).
                         * Use DUK_EXTRAOP_UNP with a dummy register to get ToNumber().
                         */
                        duk__ivalue_toforcedreg(comp_ctx, left, reg_res);
                        duk__emit_extraop_bc(comp_ctx,
                                             DUK_EXTRAOP_UNP,
                                             reg_res);  /* for side effects, result ignored */
                        duk__emit_extraop_only(comp_ctx,
                                               DUK_EXTRAOP_INVLHS);
                }

                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_REGCONST;
                res->x1.regconst = (duk_regconst_t) reg_res;
                DUK__SETTEMP(comp_ctx, reg_res + 1);
                return;
        }

 syntax_error:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_EXPRESSION);
        return;

 syntax_error_lvalue:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_LVALUE);
        return;
}

DUK_LOCAL duk_small_uint_t duk__expr_lbp(duk_compiler_ctx *comp_ctx) {
        duk_small_int_t tok = comp_ctx->curr_token.t;

        DUK_ASSERT(tok >= DUK_TOK_MINVAL && tok <= DUK_TOK_MAXVAL);
        DUK_ASSERT(sizeof(duk__token_lbp) == DUK_TOK_MAXVAL + 1);

        /* XXX: integrate support for this into led() instead?
         * Similar issue as post-increment/post-decrement.
         */

        /* prevent duk__expr_led() by using a binding power less than anything valid */
        if (tok == DUK_TOK_IN && !comp_ctx->curr_func.allow_in) {
                return 0;
        }

        if ((tok == DUK_TOK_DECREMENT || tok == DUK_TOK_INCREMENT) &&
            (comp_ctx->curr_token.lineterm)) {
                /* '++' or '--' in a post-increment/decrement position,
                 * and a LineTerminator occurs between the operator and
                 * the preceding expression.  Force the previous expr
                 * to terminate, in effect treating e.g. "a,b\n++" as
                 * "a,b;++" (= SyntaxError).
                 */
                return 0;
        }

        return DUK__TOKEN_LBP_GET_BP(duk__token_lbp[tok]);  /* format is bit packed */
}

/*
 *  Expression parsing.
 *
 *  Upon entry to 'expr' and its variants, 'curr_tok' is assumed to be the
 *  first token of the expression.  Upon exit, 'curr_tok' will be the first
 *  token not part of the expression (e.g. semicolon terminating an expression
 *  statement).
 */

#define DUK__EXPR_RBP_MASK           0xff
#define DUK__EXPR_FLAG_REJECT_IN     (1 << 8)   /* reject 'in' token (used for for-in) */
#define DUK__EXPR_FLAG_ALLOW_EMPTY   (1 << 9)   /* allow empty expression */
#define DUK__EXPR_FLAG_REQUIRE_INIT  (1 << 10)  /* require initializer for var/const */

/* main expression parser function */
DUK_LOCAL void duk__expr(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_ivalue tmp_alloc;   /* 'res' is used for "left", and 'tmp' for "right" */
        duk_ivalue *tmp = &tmp_alloc;
        duk_small_uint_t rbp;

        DUK__RECURSION_INCREASE(comp_ctx, thr);

        duk_require_stack(ctx, DUK__PARSE_EXPR_SLOTS);

        /* filter out flags from exprtop rbp_flags here to save space */
        rbp = rbp_flags & DUK__EXPR_RBP_MASK;

        DUK_DDD(DUK_DDDPRINT("duk__expr(), rbp_flags=%ld, rbp=%ld, allow_in=%ld, paren_level=%ld",
                             (long) rbp_flags, (long) rbp, (long) comp_ctx->curr_func.allow_in,
                             (long) comp_ctx->curr_func.paren_level));

        DUK_MEMZERO(&tmp_alloc, sizeof(tmp_alloc));
        tmp->x1.valstack_idx = duk_get_top(ctx);
        tmp->x2.valstack_idx = tmp->x1.valstack_idx + 1;
        duk_push_undefined(ctx);
        duk_push_undefined(ctx);

        /* XXX: where to release temp regs in intermediate expressions?
         * e.g. 1+2+3 -> don't inflate temp register count when parsing this.
         * that particular expression temp regs can be forced here.
         */

        /* XXX: increase ctx->expr_tokens here for every consumed token
         * (this would be a nice statistic)?
         */

        if (comp_ctx->curr_token.t == DUK_TOK_SEMICOLON || comp_ctx->curr_token.t == DUK_TOK_RPAREN) {
                /* XXX: possibly incorrect handling of empty expression */
                DUK_DDD(DUK_DDDPRINT("empty expression"));
                if (!(rbp_flags & DUK__EXPR_FLAG_ALLOW_EMPTY)) {
                        DUK_ERROR_SYNTAX(thr, DUK_STR_EMPTY_EXPR_NOT_ALLOWED);
                }
                res->t = DUK_IVAL_PLAIN;
                res->x1.t = DUK_ISPEC_VALUE;
                duk_push_undefined(ctx);
                duk_replace(ctx, res->x1.valstack_idx);
                goto cleanup;
        }

        duk__advance(comp_ctx);
        duk__expr_nud(comp_ctx, res);  /* reuse 'res' as 'left' */
        while (rbp < duk__expr_lbp(comp_ctx)) {
                duk__advance(comp_ctx);
                duk__expr_led(comp_ctx, res, tmp);
                duk__copy_ivalue(comp_ctx, tmp, res);  /* tmp -> res */
        }

 cleanup:
        /* final result is already in 'res' */

        duk_pop_2(ctx);

        DUK__RECURSION_DECREASE(comp_ctx, thr);
}

DUK_LOCAL void duk__exprtop(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk_hthread *thr = comp_ctx->thr;

        /* Note: these variables must reside in 'curr_func' instead of the global
         * context: when parsing function expressions, expression parsing is nested.
         */
        comp_ctx->curr_func.nud_count = 0;
        comp_ctx->curr_func.led_count = 0;
        comp_ctx->curr_func.paren_level = 0;
        comp_ctx->curr_func.expr_lhs = 1;
        comp_ctx->curr_func.allow_in = (rbp_flags & DUK__EXPR_FLAG_REJECT_IN ? 0 : 1);

        duk__expr(comp_ctx, res, rbp_flags);

        if (!(rbp_flags & DUK__EXPR_FLAG_ALLOW_EMPTY) && duk__expr_is_empty(comp_ctx)) {
                DUK_ERROR_SYNTAX(thr, DUK_STR_EMPTY_EXPR_NOT_ALLOWED);
        }
}

/* A bunch of helpers (for size optimization) that combine duk__expr()/duk__exprtop()
 * and result conversions.
 *
 * Each helper needs at least 2-3 calls to make it worth while to wrap.
 */

#if 0  /* unused */
DUK_LOCAL duk_reg_t duk__expr_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk__expr(comp_ctx, res, rbp_flags);
        return duk__ivalue_toreg(comp_ctx, res);
}
#endif

#if 0  /* unused */
DUK_LOCAL duk_reg_t duk__expr_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk__expr(comp_ctx, res, rbp_flags);
        return duk__ivalue_totemp(comp_ctx, res);
}
#endif

DUK_LOCAL void duk__expr_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags, duk_reg_t forced_reg) {
        DUK_ASSERT(forced_reg >= 0);
        duk__expr(comp_ctx, res, rbp_flags);
        duk__ivalue_toforcedreg(comp_ctx, res, forced_reg);
}

DUK_LOCAL duk_regconst_t duk__expr_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk__expr(comp_ctx, res, rbp_flags);
        return duk__ivalue_toregconst(comp_ctx, res);
}

#if 0  /* unused */
DUK_LOCAL duk_regconst_t duk__expr_totempconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk__expr(comp_ctx, res, rbp_flags);
        return duk__ivalue_totempconst(comp_ctx, res);
}
#endif

DUK_LOCAL void duk__expr_toplain(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk__expr(comp_ctx, res, rbp_flags);
        duk__ivalue_toplain(comp_ctx, res);
}

DUK_LOCAL void duk__expr_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk__expr(comp_ctx, res, rbp_flags);
        duk__ivalue_toplain_ignore(comp_ctx, res);
}

DUK_LOCAL duk_reg_t duk__exprtop_toreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk__exprtop(comp_ctx, res, rbp_flags);
        return duk__ivalue_toreg(comp_ctx, res);
}

#if 0  /* unused */
DUK_LOCAL duk_reg_t duk__exprtop_totemp(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk__exprtop(comp_ctx, res, rbp_flags);
        return duk__ivalue_totemp(comp_ctx, res);
}
#endif

DUK_LOCAL void duk__exprtop_toforcedreg(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags, duk_reg_t forced_reg) {
        DUK_ASSERT(forced_reg >= 0);
        duk__exprtop(comp_ctx, res, rbp_flags);
        duk__ivalue_toforcedreg(comp_ctx, res, forced_reg);
}

DUK_LOCAL duk_regconst_t duk__exprtop_toregconst(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t rbp_flags) {
        duk__exprtop(comp_ctx, res, rbp_flags);
        return duk__ivalue_toregconst(comp_ctx, res);
}

#if 0  /* unused */
DUK_LOCAL void duk__exprtop_toplain_ignore(duk_compiler_ctx *comp_ctx, duk_ivalue *res, int rbp_flags) {
        duk__exprtop(comp_ctx, res, rbp_flags);
        duk__ivalue_toplain_ignore(comp_ctx, res);
}
#endif

/*
 *  Parse an individual source element (top level statement) or a statement.
 *
 *  Handles labeled statements automatically (peeling away labels before
 *  parsing an expression that follows the label(s)).
 *
 *  Upon entry, 'curr_tok' contains the first token of the statement (parsed
 *  in "allow regexp literal" mode).  Upon exit, 'curr_tok' contains the first
 *  token following the statement (if the statement has a terminator, this is
 *  the token after the terminator).
 */

#ifdef DUK__HAS_VAL
#undef DUK__HAS_VAL
#endif
#ifdef DUK__HAS_TERM
#undef DUK__HAS_TERM
#endif
#ifdef DUK__ALLOW_AUTO_SEMI_ALWAYS
#undef DUK__ALLOW_AUTO_SEMI_ALWAYS
#endif
#ifdef DUK__STILL_PROLOGUE
#undef DUK__STILL_PROLOGUE
#endif
#ifdef DUK__IS_TERMINAL
#undef DUK__IS_TERMINAL
#endif

#define DUK__HAS_VAL                  (1 << 0)  /* stmt has non-empty value */
#define DUK__HAS_TERM                 (1 << 1)  /* stmt has explicit/implicit semicolon terminator */
#define DUK__ALLOW_AUTO_SEMI_ALWAYS   (1 << 2)  /* allow automatic semicolon even without lineterm (compatibility) */
#define DUK__STILL_PROLOGUE           (1 << 3)  /* statement does not terminate directive prologue */
#define DUK__IS_TERMINAL              (1 << 4)  /* statement is guaranteed to be terminal (control doesn't flow to next statement) */

/* Parse a single variable declaration (e.g. "i" or "i=10").  A leading 'var'
 * has already been eaten.  These is no return value in 'res', it is used only
 * as a temporary.
 *
 * When called from 'for-in' statement parser, the initializer expression must
 * not allow the 'in' token.  The caller supply additional expression parsing
 * flags (like DUK__EXPR_FLAG_REJECT_IN) in 'expr_flags'.
 *
 * Finally, out_rc_varname and out_reg_varbind are updated to reflect where
 * the identifier is bound:
 *
 *    If register bound:      out_reg_varbind >= 0, out_rc_varname == 0 (ignore)
 *    If not register bound:  out_reg_varbind < 0, out_rc_varname >= 0
 *
 * These allow the caller to use the variable for further assignment, e.g.
 * as is done in 'for-in' parsing.
 */

DUK_LOCAL void duk__parse_var_decl(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t expr_flags, duk_reg_t *out_reg_varbind, duk_regconst_t *out_rc_varname) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_hstring *h_varname;
        duk_reg_t reg_varbind;
        duk_regconst_t rc_varname;

        /* assume 'var' has been eaten */

        /* Note: Identifier rejects reserved words */
        if (comp_ctx->curr_token.t != DUK_TOK_IDENTIFIER) {
                goto syntax_error;
        }
        h_varname = comp_ctx->curr_token.str1;

        DUK_ASSERT(h_varname != NULL);

        /* strict mode restrictions (E5 Section 12.2.1) */
        if (duk__hstring_is_eval_or_arguments_in_strict_mode(comp_ctx, h_varname)) {
                goto syntax_error;
        }

        /* register declarations in first pass */
        if (comp_ctx->curr_func.in_scanning) {
                duk_uarridx_t n;
                DUK_DDD(DUK_DDDPRINT("register variable declaration %!O in pass 1",
                                     (duk_heaphdr *) h_varname));
                n = (duk_uarridx_t) duk_get_length(ctx, comp_ctx->curr_func.decls_idx);
                duk_push_hstring(ctx, h_varname);
                duk_put_prop_index(ctx, comp_ctx->curr_func.decls_idx, n);
                duk_push_int(ctx, DUK_DECL_TYPE_VAR + (0 << 8));
                duk_put_prop_index(ctx, comp_ctx->curr_func.decls_idx, n + 1);
        }

        duk_push_hstring(ctx, h_varname);  /* push before advancing to keep reachable */

        /* register binding lookup is based on varmap (even in first pass) */
        duk_dup_top(ctx);
        (void) duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname);

        duk__advance(comp_ctx);  /* eat identifier */

        if (comp_ctx->curr_token.t == DUK_TOK_EQUALSIGN) {
                duk__advance(comp_ctx);

                DUK_DDD(DUK_DDDPRINT("vardecl, assign to '%!O' -> reg_varbind=%ld, rc_varname=%ld",
                                     (duk_heaphdr *) h_varname, (long) reg_varbind, (long) rc_varname));

                duk__exprtop(comp_ctx, res, DUK__BP_COMMA | expr_flags /*rbp_flags*/);  /* AssignmentExpression */

                if (reg_varbind >= 0) {
                        duk__ivalue_toforcedreg(comp_ctx, res, reg_varbind);
                } else {
                        duk_reg_t reg_val;
                        reg_val = duk__ivalue_toreg(comp_ctx, res);
                        duk__emit_a_bc(comp_ctx,
                                       DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
                                       (duk_regconst_t) reg_val,
                                       rc_varname);
                }
        } else {
                if (expr_flags & DUK__EXPR_FLAG_REQUIRE_INIT) {
                        /* Used for minimal 'const': initializer required. */
                        goto syntax_error;
                }
        }

        duk_pop(ctx);  /* pop varname */

        *out_rc_varname = rc_varname;
        *out_reg_varbind = reg_varbind;

        return;

 syntax_error:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_VAR_DECLARATION);
}

DUK_LOCAL void duk__parse_var_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_small_uint_t expr_flags) {
        duk_reg_t reg_varbind;
        duk_regconst_t rc_varname;

        duk__advance(comp_ctx);  /* eat 'var' */

        for (;;) {
                /* rc_varname and reg_varbind are ignored here */
                duk__parse_var_decl(comp_ctx, res, 0 | expr_flags, &reg_varbind, &rc_varname);

                if (comp_ctx->curr_token.t != DUK_TOK_COMMA) {
                        break;
                }
                duk__advance(comp_ctx);
        }
}

DUK_LOCAL void duk__parse_for_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_int_t pc_v34_lhs;    /* start variant 3/4 left-hand-side code (L1 in doc/compiler.rst example) */
        duk_reg_t temp_reset;    /* knock back "next temp" to this whenever possible */
        duk_reg_t reg_temps;     /* preallocated temporaries (2) for variants 3 and 4 */

        DUK_DDD(DUK_DDDPRINT("start parsing a for/for-in statement"));

        /* Two temporaries are preallocated here for variants 3 and 4 which need
         * registers which are never clobbered by expressions in the loop
         * (concretely: for the enumerator object and the next enumerated value).
         * Variants 1 and 2 "release" these temps.
         */

        reg_temps = DUK__ALLOCTEMPS(comp_ctx, 2);

        temp_reset = DUK__GETTEMP(comp_ctx);

        /*
         *  For/for-in main variants are:
         *
         *    1. for (ExpressionNoIn_opt; Expression_opt; Expression_opt) Statement
         *    2. for (var VariableDeclarationNoIn; Expression_opt; Expression_opt) Statement
         *    3. for (LeftHandSideExpression in Expression) Statement
         *    4. for (var VariableDeclarationNoIn in Expression) Statement
         *
         *  Parsing these without arbitrary lookahead or backtracking is relatively
         *  tricky but we manage to do so for now.
         *
         *  See doc/compiler.rst for a detailed discussion of control flow
         *  issues, evaluation order issues, etc.
         */

        duk__advance(comp_ctx);  /* eat 'for' */
        duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

        DUK_DDD(DUK_DDDPRINT("detecting for/for-in loop variant, pc=%ld", (long) duk__get_current_pc(comp_ctx)));

        /* a label site has been emitted by duk__parse_stmt() automatically
         * (it will also emit the ENDLABEL).
         */

        if (comp_ctx->curr_token.t == DUK_TOK_VAR) {
                /*
                 *  Variant 2 or 4
                 */

                duk_reg_t reg_varbind;       /* variable binding register if register-bound (otherwise < 0) */
                duk_regconst_t rc_varname;   /* variable name reg/const, if variable not register-bound */

                duk__advance(comp_ctx);  /* eat 'var' */
                duk__parse_var_decl(comp_ctx, res, DUK__EXPR_FLAG_REJECT_IN, &reg_varbind, &rc_varname);
                DUK__SETTEMP(comp_ctx, temp_reset);

                if (comp_ctx->curr_token.t == DUK_TOK_IN) {
                        /*
                         *  Variant 4
                         */

                        DUK_DDD(DUK_DDDPRINT("detected for variant 4: for (var VariableDeclarationNoIn in Expression) Statement"));
                        pc_v34_lhs = duk__get_current_pc(comp_ctx);  /* jump is inserted here */
                        if (reg_varbind >= 0) {
                                duk__emit_a_bc(comp_ctx,
                                               DUK_OP_LDREG,
                                               (duk_regconst_t) reg_varbind,
                                               (duk_regconst_t) (reg_temps + 0));
                        } else {
                                duk__emit_a_bc(comp_ctx,
                                               DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
                                               (duk_regconst_t) (reg_temps + 0),
                                               rc_varname);
                        }
                        goto parse_3_or_4;
                } else {
                        /*
                         *  Variant 2
                         */

                        DUK_DDD(DUK_DDDPRINT("detected for variant 2: for (var VariableDeclarationNoIn; Expression_opt; Expression_opt) Statement"));
                        for (;;) {
                                /* more initializers */
                                if (comp_ctx->curr_token.t != DUK_TOK_COMMA) {
                                        break;
                                }
                                DUK_DDD(DUK_DDDPRINT("variant 2 has another variable initializer"));

                                duk__advance(comp_ctx);  /* eat comma */
                                duk__parse_var_decl(comp_ctx, res, DUK__EXPR_FLAG_REJECT_IN, &reg_varbind, &rc_varname);
                        }
                        goto parse_1_or_2;
                }
        } else {
                /*
                 *  Variant 1 or 3
                 */

                pc_v34_lhs = duk__get_current_pc(comp_ctx);  /* jump is inserted here (variant 3) */

                /* Note that duk__exprtop() here can clobber any reg above current temp_next,
                 * so any loop variables (e.g. enumerator) must be "preallocated".
                 */

                /* don't coerce yet to a plain value (variant 3 needs special handling) */
                duk__exprtop(comp_ctx, res, DUK__BP_FOR_EXPR | DUK__EXPR_FLAG_REJECT_IN | DUK__EXPR_FLAG_ALLOW_EMPTY /*rbp_flags*/);  /* Expression */
                if (comp_ctx->curr_token.t == DUK_TOK_IN) {
                        /*
                         *  Variant 3
                         */

                        /* XXX: need to determine LHS type, and check that it is LHS compatible */
                        DUK_DDD(DUK_DDDPRINT("detected for variant 3: for (LeftHandSideExpression in Expression) Statement"));
                        if (duk__expr_is_empty(comp_ctx)) {
                                goto syntax_error;  /* LeftHandSideExpression does not allow empty expression */
                        }

                        if (res->t == DUK_IVAL_VAR) {
                                duk_reg_t reg_varbind;
                                duk_regconst_t rc_varname;

                                duk_dup(ctx, res->x1.valstack_idx);
                                if (duk__lookup_lhs(comp_ctx, &reg_varbind, &rc_varname)) {
                                        duk__emit_a_bc(comp_ctx,
                                                       DUK_OP_LDREG,
                                                       (duk_regconst_t) reg_varbind,
                                                       (duk_regconst_t) (reg_temps + 0));
                                } else {
                                        duk__emit_a_bc(comp_ctx,
                                                       DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
                                                       (duk_regconst_t) (reg_temps + 0),
                                                       rc_varname);
                                }
                        } else if (res->t == DUK_IVAL_PROP) {
                                /* Don't allow a constant for the object (even for a number etc), as
                                 * it goes into the 'A' field of the opcode.
                                 */
                                duk_reg_t reg_obj;
                                duk_regconst_t rc_key;
                                reg_obj = duk__ispec_toregconst_raw(comp_ctx, &res->x1, -1 /*forced_reg*/, 0 /*flags*/);  /* don't allow const */
                                rc_key = duk__ispec_toregconst_raw(comp_ctx, &res->x2, -1 /*forced_reg*/, DUK__IVAL_FLAG_ALLOW_CONST /*flags*/);
                                duk__emit_a_b_c(comp_ctx,
                                                DUK_OP_PUTPROP | DUK__EMIT_FLAG_A_IS_SOURCE,
                                                (duk_regconst_t) reg_obj,
                                                rc_key,
                                                (duk_regconst_t) (reg_temps + 0));
                        } else {
                                duk__ivalue_toplain_ignore(comp_ctx, res);  /* just in case */
                                duk__emit_extraop_only(comp_ctx,
                                                       DUK_EXTRAOP_INVLHS);
                        }
                        goto parse_3_or_4;
                } else {
                        /*
                         *  Variant 1
                         */

                        DUK_DDD(DUK_DDDPRINT("detected for variant 1: for (ExpressionNoIn_opt; Expression_opt; Expression_opt) Statement"));
                        duk__ivalue_toplain_ignore(comp_ctx, res);
                        goto parse_1_or_2;
                }
        }

 parse_1_or_2:
        /*
         *  Parse variant 1 or 2.  The first part expression (which differs
         *  in the variants) has already been parsed and its code emitted.
         *
         *  reg_temps + 0: unused
         *  reg_temps + 1: unused
         */
        {
                duk_regconst_t rc_cond;
                duk_int_t pc_l1, pc_l2, pc_l3, pc_l4;
                duk_int_t pc_jumpto_l3, pc_jumpto_l4;
                duk_bool_t expr_c_empty;

                DUK_DDD(DUK_DDDPRINT("shared code for parsing variants 1 and 2"));

                /* "release" preallocated temps since we won't need them */
                temp_reset = reg_temps + 0;
                DUK__SETTEMP(comp_ctx, temp_reset);

                duk__advance_expect(comp_ctx, DUK_TOK_SEMICOLON);

                pc_l1 = duk__get_current_pc(comp_ctx);
                duk__exprtop(comp_ctx, res, DUK__BP_FOR_EXPR | DUK__EXPR_FLAG_ALLOW_EMPTY /*rbp_flags*/);  /* Expression_opt */
                if (duk__expr_is_empty(comp_ctx)) {
                        /* no need to coerce */
                        pc_jumpto_l3 = duk__emit_jump_empty(comp_ctx);  /* to body */
                        pc_jumpto_l4 = -1;  /* omitted */
                } else {
                        rc_cond = duk__ivalue_toregconst(comp_ctx, res);
                        duk__emit_if_false_skip(comp_ctx, rc_cond);
                        pc_jumpto_l3 = duk__emit_jump_empty(comp_ctx);  /* to body */
                        pc_jumpto_l4 = duk__emit_jump_empty(comp_ctx);  /* to exit */
                }
                DUK__SETTEMP(comp_ctx, temp_reset);

                duk__advance_expect(comp_ctx, DUK_TOK_SEMICOLON);

                pc_l2 = duk__get_current_pc(comp_ctx);
                duk__exprtop(comp_ctx, res, DUK__BP_FOR_EXPR | DUK__EXPR_FLAG_ALLOW_EMPTY /*rbp_flags*/);  /* Expression_opt */
                if (duk__expr_is_empty(comp_ctx)) {
                        /* no need to coerce */
                        expr_c_empty = 1;
                        /* JUMP L1 omitted */
                } else {
                        duk__ivalue_toplain_ignore(comp_ctx, res);
                        expr_c_empty = 0;
                        duk__emit_jump(comp_ctx, pc_l1);
                }
                DUK__SETTEMP(comp_ctx, temp_reset);

                duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

                pc_l3 = duk__get_current_pc(comp_ctx);
                duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
                if (expr_c_empty) {
                        duk__emit_jump(comp_ctx, pc_l1);
                } else {
                        duk__emit_jump(comp_ctx, pc_l2);
                }
                /* temp reset is not necessary after duk__parse_stmt(), which already does it */

                pc_l4 = duk__get_current_pc(comp_ctx);

                DUK_DDD(DUK_DDDPRINT("patching jumps: jumpto_l3: %ld->%ld, jumpto_l4: %ld->%ld, "
                                     "break: %ld->%ld, continue: %ld->%ld",
                                     (long) pc_jumpto_l3, (long) pc_l3, (long) pc_jumpto_l4, (long) pc_l4,
                                     (long) (pc_label_site + 1), (long) pc_l4, (long) (pc_label_site + 2), (long) pc_l2));

                duk__patch_jump(comp_ctx, pc_jumpto_l3, pc_l3);
                duk__patch_jump(comp_ctx, pc_jumpto_l4, pc_l4);
                duk__patch_jump(comp_ctx,
                                pc_label_site + 1,
                                pc_l4);                         /* break jump */
                duk__patch_jump(comp_ctx,
                                pc_label_site + 2,
                                expr_c_empty ? pc_l1 : pc_l2);  /* continue jump */
        }
        goto finished;

 parse_3_or_4:
        /*
         *  Parse variant 3 or 4.
         *
         *  For variant 3 (e.g. "for (A in C) D;") the code for A (except the
         *  final property/variable write) has already been emitted.  The first
         *  instruction of that code is at pc_v34_lhs; a JUMP needs to be inserted
         *  there to satisfy control flow needs.
         *
         *  For variant 4, if the variable declaration had an initializer
         *  (e.g. "for (var A = B in C) D;") the code for the assignment
         *  (B) has already been emitted.
         *
         *  Variables set before entering here:
         *
         *    pc_v34_lhs:    insert a "JUMP L2" here (see doc/compiler.rst example).
         *    reg_temps + 0: iteration target value (written to LHS)
         *    reg_temps + 1: enumerator object
         */
        {
                duk_int_t pc_l1, pc_l2, pc_l3, pc_l4, pc_l5;
                duk_int_t pc_jumpto_l2, pc_jumpto_l3, pc_jumpto_l4, pc_jumpto_l5;
                duk_reg_t reg_target;

                DUK_DDD(DUK_DDDPRINT("shared code for parsing variants 3 and 4, pc_v34_lhs=%ld", (long) pc_v34_lhs));

                DUK__SETTEMP(comp_ctx, temp_reset);

                /* First we need to insert a jump in the middle of previously
                 * emitted code to get the control flow right.  No jumps can
                 * cross the position where the jump is inserted.  See doc/compiler.rst
                 * for discussion on the intricacies of control flow and side effects
                 * for variants 3 and 4.
                 */

                duk__insert_jump_entry(comp_ctx, pc_v34_lhs);
                pc_jumpto_l2 = pc_v34_lhs;  /* inserted jump */
                pc_l1 = pc_v34_lhs + 1;     /* +1, right after inserted jump */

                /* The code for writing reg_temps + 0 to the left hand side has already
                 * been emitted.
                 */

                pc_jumpto_l3 = duk__emit_jump_empty(comp_ctx);  /* -> loop body */

                duk__advance(comp_ctx);  /* eat 'in' */

                /* Parse enumeration target and initialize enumerator.  For 'null' and 'undefined',
                 * INITENUM will creates a 'null' enumerator which works like an empty enumerator
                 * (E5 Section 12.6.4, step 3).  Note that INITENUM requires the value to be in a
                 * register (constant not allowed).
                 */

                pc_l2 = duk__get_current_pc(comp_ctx);
                reg_target = duk__exprtop_toreg(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);  /* Expression */
                duk__emit_extraop_b_c(comp_ctx,
                                      DUK_EXTRAOP_INITENUM | DUK__EMIT_FLAG_B_IS_TARGET,
                                      (duk_regconst_t) (reg_temps + 1),
                                      (duk_regconst_t) reg_target);
                pc_jumpto_l4 = duk__emit_jump_empty(comp_ctx);
                DUK__SETTEMP(comp_ctx, temp_reset);

                duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

                pc_l3 = duk__get_current_pc(comp_ctx);
                duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
                /* temp reset is not necessary after duk__parse_stmt(), which already does it */

                /* NEXTENUM needs a jump slot right after the main opcode.
                 * We need the code emitter to reserve the slot: if there's
                 * target shuffling, the target shuffle opcodes must happen
                 * after the jump slot (for NEXTENUM the shuffle opcodes are
                 * not needed if the enum is finished).
                 */
                pc_l4 = duk__get_current_pc(comp_ctx);
                duk__emit_extraop_b_c(comp_ctx,
                                      DUK_EXTRAOP_NEXTENUM | DUK__EMIT_FLAG_B_IS_TARGET | DUK__EMIT_FLAG_RESERVE_JUMPSLOT,
                                      (duk_regconst_t) (reg_temps + 0),
                                      (duk_regconst_t) (reg_temps + 1));
                pc_jumpto_l5 = comp_ctx->emit_jumpslot_pc;  /* NEXTENUM jump slot: executed when enum finished */
                duk__emit_jump(comp_ctx, pc_l1);  /* jump to next loop, using reg_v34_iter as iterated value */

                pc_l5 = duk__get_current_pc(comp_ctx);

                /* XXX: since the enumerator may be a memory expensive object,
                 * perhaps clear it explicitly here?  If so, break jump must
                 * go through this clearing operation.
                 */

                DUK_DDD(DUK_DDDPRINT("patching jumps: jumpto_l2: %ld->%ld, jumpto_l3: %ld->%ld, "
                                     "jumpto_l4: %ld->%ld, jumpto_l5: %ld->%ld, "
                                     "break: %ld->%ld, continue: %ld->%ld",
                                     (long) pc_jumpto_l2, (long) pc_l2, (long) pc_jumpto_l3, (long) pc_l3,
                                     (long) pc_jumpto_l4, (long) pc_l4, (long) pc_jumpto_l5, (long) pc_l5,
                                     (long) (pc_label_site + 1), (long) pc_l5, (long) (pc_label_site + 2), (long) pc_l4));

                duk__patch_jump(comp_ctx, pc_jumpto_l2, pc_l2);
                duk__patch_jump(comp_ctx, pc_jumpto_l3, pc_l3);
                duk__patch_jump(comp_ctx, pc_jumpto_l4, pc_l4);
                duk__patch_jump(comp_ctx, pc_jumpto_l5, pc_l5);
                duk__patch_jump(comp_ctx, pc_label_site + 1, pc_l5);  /* break jump */
                duk__patch_jump(comp_ctx, pc_label_site + 2, pc_l4);  /* continue jump */
        }
        goto finished;

 finished:
        DUK_DDD(DUK_DDDPRINT("end parsing a for/for-in statement"));
        return;

 syntax_error:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_FOR);
}

DUK_LOCAL void duk__parse_switch_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site) {
        duk_hthread *thr = comp_ctx->thr;
        duk_reg_t temp_at_loop;
        duk_regconst_t rc_switch;    /* reg/const for switch value */
        duk_regconst_t rc_case;      /* reg/const for case value */
        duk_reg_t reg_temp;          /* general temp register */
        duk_int_t pc_prevcase = -1;
        duk_int_t pc_prevstmt = -1;
        duk_int_t pc_default = -1;   /* -1 == not set, -2 == pending (next statement list) */

        /* Note: negative pc values are ignored when patching jumps, so no explicit checks needed */

        /*
         *  Switch is pretty complicated because of several conflicting concerns:
         *
         *    - Want to generate code without an intermediate representation,
         *      i.e., in one go
         *
         *    - Case selectors are expressions, not values, and may thus e.g. throw
         *      exceptions (which causes evaluation order concerns)
         *
         *    - Evaluation semantics of case selectors and default clause need to be
         *      carefully implemented to provide correct behavior even with case value
         *      side effects
         *
         *    - Fall through case and default clauses; avoiding dead JUMPs if case
         *      ends with an unconditional jump (a break or a continue)
         *
         *    - The same case value may occur multiple times, but evaluation rules
         *      only process the first match before switching to a "propagation" mode
         *      where case values are no longer evaluated
         *
         *  See E5 Section 12.11.  Also see doc/compiler.rst for compilation
         *  discussion.
         */

        duk__advance(comp_ctx);
        duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);
        rc_switch = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
        duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);
        duk__advance_expect(comp_ctx, DUK_TOK_LCURLY);

        DUK_DDD(DUK_DDDPRINT("switch value in register %ld", (long) rc_switch));

        temp_at_loop = DUK__GETTEMP(comp_ctx);

        for (;;) {
                duk_int_t num_stmts;
                duk_small_int_t tok;

                /* sufficient for keeping temp reg numbers in check */
                DUK__SETTEMP(comp_ctx, temp_at_loop);

                if (comp_ctx->curr_token.t == DUK_TOK_RCURLY) {
                        break;
                }

                /*
                 *  Parse a case or default clause.
                 */

                if (comp_ctx->curr_token.t == DUK_TOK_CASE) {
                        /*
                         *  Case clause.
                         *
                         *  Note: cannot use reg_case as a temp register (for SEQ target)
                         *  because it may be a constant.
                         */

                        duk__patch_jump_here(comp_ctx, pc_prevcase);  /* chain jumps for case
                                                                       * evaluation and checking
                                                                       */

                        duk__advance(comp_ctx);
                        rc_case = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
                        duk__advance_expect(comp_ctx, DUK_TOK_COLON);

                        reg_temp = DUK__ALLOCTEMP(comp_ctx);
                        duk__emit_a_b_c(comp_ctx,
                                        DUK_OP_SEQ,
                                        (duk_regconst_t) reg_temp,
                                        rc_switch,
                                        rc_case);
                        duk__emit_if_true_skip(comp_ctx, (duk_regconst_t) reg_temp);

                        /* jump to next case clause */
                        pc_prevcase = duk__emit_jump_empty(comp_ctx);  /* no match, next case */

                        /* statements go here (if any) on next loop */
                } else if (comp_ctx->curr_token.t == DUK_TOK_DEFAULT) {
                        /*
                         *  Default clause.
                         */

                        if (pc_default >= 0) {
                                goto syntax_error;
                        }
                        duk__advance(comp_ctx);
                        duk__advance_expect(comp_ctx, DUK_TOK_COLON);

                        /* Fix for https://github.com/svaarala/duktape/issues/155:
                         * If 'default' is first clause (detected by pc_prevcase < 0)
                         * we need to ensure we stay in the matching chain.
                         */
                        if (pc_prevcase < 0) {
                                DUK_DD(DUK_DDPRINT("default clause is first, emit prevcase jump"));
                                pc_prevcase = duk__emit_jump_empty(comp_ctx);
                        }

                        /* default clause matches next statement list (if any) */
                        pc_default = -2;
                } else {
                        /* Code is not accepted before the first case/default clause */
                        goto syntax_error;
                }

                /*
                 *  Parse code after the clause.  Possible terminators are
                 *  'case', 'default', and '}'.
                 *
                 *  Note that there may be no code at all, not even an empty statement,
                 *  between case clauses.  This must be handled just like an empty statement
                 *  (omitting seemingly pointless JUMPs), to avoid situations like
                 *  test-bug-case-fallthrough.js.
                 */

                num_stmts = 0;
                if (pc_default == -2) {
                        pc_default = duk__get_current_pc(comp_ctx);
                }

                /* Note: this is correct even for default clause statements:
                 * they participate in 'fall-through' behavior even if the
                 * default clause is in the middle.
                 */
                duk__patch_jump_here(comp_ctx, pc_prevstmt);  /* chain jumps for 'fall-through'
                                                               * after a case matches.
                                                               */

                for (;;) {
                        tok = comp_ctx->curr_token.t;
                        if (tok == DUK_TOK_CASE || tok == DUK_TOK_DEFAULT ||
                            tok == DUK_TOK_RCURLY) {
                                break;
                        }
                        num_stmts++;
                        duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
                }

                /* fall-through jump to next code of next case (backpatched) */
                pc_prevstmt = duk__emit_jump_empty(comp_ctx);

                /* XXX: would be nice to omit this jump when the jump is not
                 * reachable, at least in the obvious cases (such as the case
                 * ending with a 'break'.
                 *
                 * Perhaps duk__parse_stmt() could provide some info on whether
                 * the statement is a "dead end"?
                 *
                 * If implemented, just set pc_prevstmt to -1 when not needed.
                 */
        }

        DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_RCURLY);
        duk__advance(comp_ctx);

        /* default case control flow patchup; note that if pc_prevcase < 0
         * (i.e. no case clauses), control enters default case automatically.
         */
        if (pc_default >= 0) {
                /* default case exists: go there if no case matches */
                duk__patch_jump(comp_ctx, pc_prevcase, pc_default);
        } else {
                /* default case does not exist, or no statements present
                 * after default case: finish case evaluation
                 */
                duk__patch_jump_here(comp_ctx, pc_prevcase);
        }

        /* fall-through control flow patchup; note that pc_prevstmt may be
         * < 0 (i.e. no case clauses), in which case this is a no-op.
         */
        duk__patch_jump_here(comp_ctx, pc_prevstmt);

        /* continue jump not patched, an INVALID opcode remains there */
        duk__patch_jump_here(comp_ctx, pc_label_site + 1);  /* break jump */

        /* Note: 'fast' breaks will jump to pc_label_site + 1, which will
         * then jump here.  The double jump will be eliminated by a
         * peephole pass, resulting in an optimal jump here.  The label
         * site jumps will remain in bytecode and will waste code size.
         */

        return;

 syntax_error:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_SWITCH);
}

DUK_LOCAL void duk__parse_if_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_reg_t temp_reset;
        duk_regconst_t rc_cond;
        duk_int_t pc_jump_false;

        DUK_DDD(DUK_DDDPRINT("begin parsing if statement"));

        temp_reset = DUK__GETTEMP(comp_ctx);

        duk__advance(comp_ctx);  /* eat 'if' */
        duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

        rc_cond = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
        duk__emit_if_true_skip(comp_ctx, rc_cond);
        pc_jump_false = duk__emit_jump_empty(comp_ctx);  /* jump to end or else part */
        DUK__SETTEMP(comp_ctx, temp_reset);

        duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

        duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);

        /* The 'else' ambiguity is resolved by 'else' binding to the innermost
         * construct, so greedy matching is correct here.
         */

        if (comp_ctx->curr_token.t == DUK_TOK_ELSE) {
                duk_int_t pc_jump_end;

                DUK_DDD(DUK_DDDPRINT("if has else part"));

                duk__advance(comp_ctx);

                pc_jump_end = duk__emit_jump_empty(comp_ctx);  /* jump from true part to end */
                duk__patch_jump_here(comp_ctx, pc_jump_false);

                duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);

                duk__patch_jump_here(comp_ctx, pc_jump_end);
        } else {
                DUK_DDD(DUK_DDDPRINT("if does not have else part"));

                duk__patch_jump_here(comp_ctx, pc_jump_false);
        }

        DUK_DDD(DUK_DDDPRINT("end parsing if statement"));
}

DUK_LOCAL void duk__parse_do_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site) {
        duk_regconst_t rc_cond;
        duk_int_t pc_start;

        DUK_DDD(DUK_DDDPRINT("begin parsing do statement"));

        duk__advance(comp_ctx);  /* eat 'do' */

        pc_start = duk__get_current_pc(comp_ctx);
        duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
        duk__patch_jump_here(comp_ctx, pc_label_site + 2);  /* continue jump */

        duk__advance_expect(comp_ctx, DUK_TOK_WHILE);
        duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

        rc_cond = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
        duk__emit_if_false_skip(comp_ctx, rc_cond);
        duk__emit_jump(comp_ctx, pc_start);
        /* no need to reset temps, as we're finished emitting code */

        duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

        duk__patch_jump_here(comp_ctx, pc_label_site + 1);  /* break jump */

        DUK_DDD(DUK_DDDPRINT("end parsing do statement"));
}

DUK_LOCAL void duk__parse_while_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_int_t pc_label_site) {
        duk_reg_t temp_reset;
        duk_regconst_t rc_cond;
        duk_int_t pc_start;
        duk_int_t pc_jump_false;

        DUK_DDD(DUK_DDDPRINT("begin parsing while statement"));

        temp_reset = DUK__GETTEMP(comp_ctx);

        duk__advance(comp_ctx);  /* eat 'while' */

        duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

        pc_start = duk__get_current_pc(comp_ctx);
        duk__patch_jump_here(comp_ctx, pc_label_site + 2);  /* continue jump */

        rc_cond = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
        duk__emit_if_true_skip(comp_ctx, rc_cond);
        pc_jump_false = duk__emit_jump_empty(comp_ctx);
        DUK__SETTEMP(comp_ctx, temp_reset);

        duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

        duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
        duk__emit_jump(comp_ctx, pc_start);

        duk__patch_jump_here(comp_ctx, pc_jump_false);
        duk__patch_jump_here(comp_ctx, pc_label_site + 1);  /* break jump */

        DUK_DDD(DUK_DDDPRINT("end parsing while statement"));
}

DUK_LOCAL void duk__parse_break_or_continue_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_hthread *thr = comp_ctx->thr;
        duk_bool_t is_break = (comp_ctx->curr_token.t == DUK_TOK_BREAK);
        duk_int_t label_id;
        duk_int_t label_catch_depth;
        duk_int_t label_pc;  /* points to LABEL; pc+1 = jump site for break; pc+2 = jump site for continue */
        duk_bool_t label_is_closest;

        DUK_UNREF(res);

        duk__advance(comp_ctx);  /* eat 'break' or 'continue' */

        if (comp_ctx->curr_token.t == DUK_TOK_SEMICOLON ||  /* explicit semi follows */
            comp_ctx->curr_token.lineterm ||                /* automatic semi will be inserted */
            comp_ctx->curr_token.allow_auto_semi) {         /* automatic semi will be inserted */
                /* break/continue without label */

                duk__lookup_active_label(comp_ctx, DUK_HTHREAD_STRING_EMPTY_STRING(thr), is_break, &label_id, &label_catch_depth, &label_pc, &label_is_closest);
        } else if (comp_ctx->curr_token.t == DUK_TOK_IDENTIFIER) {
                /* break/continue with label (label cannot be a reserved word, production is 'Identifier' */
                DUK_ASSERT(comp_ctx->curr_token.str1 != NULL);
                duk__lookup_active_label(comp_ctx, comp_ctx->curr_token.str1, is_break, &label_id, &label_catch_depth, &label_pc, &label_is_closest);
                duk__advance(comp_ctx);
        } else {
                DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_BREAK_CONT_LABEL);
        }

        /* Use a fast break/continue when possible.  A fast break/continue is
         * just a jump to the LABEL break/continue jump slot, which then jumps
         * to an appropriate place (for break, going through ENDLABEL correctly).
         * The peephole optimizer will optimize the jump to a direct one.
         */

        if (label_catch_depth == comp_ctx->curr_func.catch_depth &&
            label_is_closest) {
                DUK_DDD(DUK_DDDPRINT("break/continue: is_break=%ld, label_id=%ld, label_is_closest=%ld, "
                                     "label_catch_depth=%ld, catch_depth=%ld "
                                     "-> use fast variant (direct jump)",
                                     (long) is_break, (long) label_id, (long) label_is_closest,
                                     (long) label_catch_depth, (long) comp_ctx->curr_func.catch_depth));

                duk__emit_jump(comp_ctx, label_pc + (is_break ? 1 : 2));
        } else {
                DUK_DDD(DUK_DDDPRINT("break/continue: is_break=%ld, label_id=%ld, label_is_closest=%ld, "
                                     "label_catch_depth=%ld, catch_depth=%ld "
                                     "-> use slow variant (longjmp)",
                                     (long) is_break, (long) label_id, (long) label_is_closest,
                                     (long) label_catch_depth, (long) comp_ctx->curr_func.catch_depth));

                duk__emit_extraop_bc(comp_ctx,
                              is_break ? DUK_EXTRAOP_BREAK : DUK_EXTRAOP_CONTINUE,
                              (duk_regconst_t) label_id);
        }
}

DUK_LOCAL void duk__parse_return_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_hthread *thr = comp_ctx->thr;
        duk_regconst_t rc_val;
        duk_small_uint_t ret_flags;

        duk__advance(comp_ctx);  /* eat 'return' */

        /* A 'return' statement is only allowed inside an actual function body,
         * not as part of eval or global code.
         */
        if (!comp_ctx->curr_func.is_function) {
                DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_RETURN);
        }

        ret_flags = 0;

        if (comp_ctx->curr_token.t == DUK_TOK_SEMICOLON ||  /* explicit semi follows */
            comp_ctx->curr_token.lineterm ||                /* automatic semi will be inserted */
            comp_ctx->curr_token.allow_auto_semi) {         /* automatic semi will be inserted */
                DUK_DDD(DUK_DDDPRINT("empty return value -> undefined"));
                rc_val = 0;
        } else {
                duk_int_t pc_before_expr;
                duk_int_t pc_after_expr;

                DUK_DDD(DUK_DDDPRINT("return with a value"));

                DUK_UNREF(pc_before_expr);
                DUK_UNREF(pc_after_expr);

                pc_before_expr = duk__get_current_pc(comp_ctx);
                rc_val = duk__exprtop_toregconst(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
                pc_after_expr = duk__get_current_pc(comp_ctx);

                /* Tail call check: if last opcode emitted was CALL(I), and
                 * the context allows it, change the CALL(I) to a tail call.
                 * This doesn't guarantee that a tail call will be allowed at
                 * runtime, so the RETURN must still be emitted.  (Duktape
                 * 0.10.0 avoided this and simulated a RETURN if a tail call
                 * couldn't be used at runtime; but this didn't work
                 * correctly with a thread yield/resume, see
                 * test-bug-tailcall-thread-yield-resume.js for discussion.)
                 *
                 * In addition to the last opcode being CALL, we also need to
                 * be sure that 'rc_val' is the result register of the CALL(I).
                 * For instance, for the expression 'return 0, (function ()
                 * { return 1; }), 2' the last opcode emitted is CALL (no
                 * bytecode is emitted for '2') but 'rc_val' indicates
                 * constant '2'.  Similarly if '2' is replaced by a register
                 * bound variable, no opcodes are emitted but tail call would
                 * be incorrect.
                 *
                 * This is tricky and easy to get wrong.  It would be best to
                 * track enough expression metadata to check that 'rc_val' came
                 * from that last CALL instruction.  We don't have that metadata
                 * now, so we check that 'rc_val' is a temporary register result
                 * (not a constant or a register bound variable).  There should
                 * be no way currently for 'rc_val' to be a temporary for an
                 * expression following the CALL instruction without emitting
                 * some opcodes following the CALL.  This proxy check is used
                 * below.
                 *
                 * See: test-bug-comma-expr-gh131.js.
                 *
                 * The non-standard 'caller' property disables tail calls
                 * because they pose some special cases which haven't been
                 * fixed yet.
                 */

#if defined(DUK_USE_TAILCALL)
                if (comp_ctx->curr_func.catch_depth == 0 &&   /* no catchers */
                    pc_after_expr > pc_before_expr) {         /* at least one opcode emitted */
                        duk_compiler_instr *instr;
                        duk_small_uint_t op;

                        instr = duk__get_instr_ptr(comp_ctx, pc_after_expr - 1);
                        DUK_ASSERT(instr != NULL);

                        op = (duk_small_uint_t) DUK_DEC_OP(instr->ins);
                        if ((op == DUK_OP_CALL || op == DUK_OP_CALLI) &&
                            DUK__ISTEMP(comp_ctx, rc_val) /* see above */) {
                                DUK_DDD(DUK_DDDPRINT("return statement detected a tail call opportunity: "
                                                     "catch depth is 0, duk__exprtop() emitted >= 1 instructions, "
                                                     "and last instruction is a CALL "
                                                     "-> set TAILCALL flag"));
                                /* Just flip the single bit. */
                                instr->ins |= DUK_ENC_OP_A_B_C(0, DUK_BC_CALL_FLAG_TAILCALL, 0, 0);
                        }
                }
#endif  /* DUK_USE_TAILCALL */

                ret_flags = DUK_BC_RETURN_FLAG_HAVE_RETVAL;
        }

        duk__emit_a_b(comp_ctx,
                      DUK_OP_RETURN | DUK__EMIT_FLAG_NO_SHUFFLE_A,
                      (duk_regconst_t) ret_flags /*flags*/,
                      rc_val /*reg*/);
}

DUK_LOCAL void duk__parse_throw_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_reg_t reg_val;

        duk__advance(comp_ctx);  /* eat 'throw' */

        /* Unlike break/continue, throw statement does not allow an empty value. */

        if (comp_ctx->curr_token.lineterm) {
                DUK_ERROR_SYNTAX(comp_ctx->thr, DUK_STR_INVALID_THROW);
        }

        reg_val = duk__exprtop_toreg(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);
        duk__emit_extraop_bc(comp_ctx,
                             DUK_EXTRAOP_THROW,
                             (duk_regconst_t) reg_val);
}

DUK_LOCAL void duk__parse_try_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_reg_t reg_catch;      /* reg_catch+0 and reg_catch+1 are reserved for TRYCATCH */
        duk_regconst_t rc_varname = 0;
        duk_small_uint_t trycatch_flags = 0;
        duk_int_t pc_ldconst = -1;
        duk_int_t pc_trycatch = -1;
        duk_int_t pc_catch = -1;
        duk_int_t pc_finally = -1;

        DUK_UNREF(res);

        /*
         *  See the following documentation for discussion:
         *
         *    doc/execution.rst: control flow details
         *
         *  Try, catch, and finally "parts" are Blocks, not Statements, so
         *  they must always be delimited by curly braces.  This is unlike e.g.
         *  the if statement, which accepts any Statement.  This eliminates any
         *  questions of matching parts of nested try statements.  The Block
         *  parsing is implemented inline here (instead of calling out).
         *
         *  Finally part has a 'let scoped' variable, which requires a few kinks
         *  here.
         */

        comp_ctx->curr_func.catch_depth++;

        duk__advance(comp_ctx);  /* eat 'try' */

        reg_catch = DUK__ALLOCTEMPS(comp_ctx, 2);

        /* The target for this LDCONST may need output shuffling, but we assume
         * that 'pc_ldconst' will be the LDCONST that we can patch later.  This
         * should be the case because there's no input shuffling.  (If there's
         * no catch clause, this LDCONST will be replaced with a NOP.)
         */
        pc_ldconst = duk__get_current_pc(comp_ctx);
        duk__emit_a_bc(comp_ctx, DUK_OP_LDCONST, reg_catch, 0 /*patched later*/);

        pc_trycatch = duk__get_current_pc(comp_ctx);
        duk__emit_invalid(comp_ctx);  /* TRYCATCH, cannot emit now (not enough info) */
        duk__emit_invalid(comp_ctx);  /* jump for 'catch' case */
        duk__emit_invalid(comp_ctx);  /* jump for 'finally' case or end (if no finally) */

        /* try part */
        duk__advance_expect(comp_ctx, DUK_TOK_LCURLY);
        duk__parse_stmts(comp_ctx, 0 /*allow_source_elem*/, 0 /*expect_eof*/);
        /* the DUK_TOK_RCURLY is eaten by duk__parse_stmts() */
        duk__emit_extraop_only(comp_ctx,
                               DUK_EXTRAOP_ENDTRY);

        if (comp_ctx->curr_token.t == DUK_TOK_CATCH) {
                /*
                 *  The catch variable must be updated to reflect the new allocated
                 *  register for the duration of the catch clause.  We need to store
                 *  and restore the original value for the varmap entry (if any).
                 */

                /*
                 *  Note: currently register bindings must be fixed for the entire
                 *  function.  So, even though the catch variable is in a register
                 *  we know, we must use an explicit environment record and slow path
                 *  accesses to read/write the catch binding to make closures created
                 *  within the catch clause work correctly.  This restriction should
                 *  be fixable (at least in common cases) later.
                 *
                 *  See: test-bug-catch-binding-2.js.
                 *
                 *  XXX: improve to get fast path access to most catch clauses.
                 */

                duk_hstring *h_var;
                duk_int_t varmap_value;  /* for storing/restoring the varmap binding for catch variable */

                DUK_DDD(DUK_DDDPRINT("stack top at start of catch clause: %ld", (long) duk_get_top(ctx)));

                trycatch_flags |= DUK_BC_TRYCATCH_FLAG_HAVE_CATCH;

                pc_catch = duk__get_current_pc(comp_ctx);

                duk__advance(comp_ctx);
                duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

                if (comp_ctx->curr_token.t != DUK_TOK_IDENTIFIER) {
                        /* Identifier, i.e. don't allow reserved words */
                        goto syntax_error;
                }
                h_var = comp_ctx->curr_token.str1;
                DUK_ASSERT(h_var != NULL);

                duk_push_hstring(ctx, h_var);  /* keep in on valstack, use borrowed ref below */

                if (comp_ctx->curr_func.is_strict &&
                    ((h_var == DUK_HTHREAD_STRING_EVAL(thr)) ||
                     (h_var == DUK_HTHREAD_STRING_LC_ARGUMENTS(thr)))) {
                        DUK_DDD(DUK_DDDPRINT("catch identifier 'eval' or 'arguments' in strict mode -> SyntaxError"));
                        goto syntax_error;
                }

                duk_dup_top(ctx);
                rc_varname = duk__getconst(comp_ctx);
                DUK_DDD(DUK_DDDPRINT("catch clause, rc_varname=0x%08lx (%ld)",
                                     (unsigned long) rc_varname, (long) rc_varname));

                duk__advance(comp_ctx);
                duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

                duk__advance_expect(comp_ctx, DUK_TOK_LCURLY);

                DUK_DDD(DUK_DDDPRINT("varmap before modifying for catch clause: %!iT",
                                     (duk_tval *) duk_get_tval(ctx, comp_ctx->curr_func.varmap_idx)));

                duk_dup_top(ctx);
                duk_get_prop(ctx, comp_ctx->curr_func.varmap_idx);
                if (duk_is_undefined(ctx, -1)) {
                        varmap_value = -2;
                } else if (duk_is_null(ctx, -1)) {
                        varmap_value = -1;
                } else {
                        DUK_ASSERT(duk_is_number(ctx, -1));
                        varmap_value = duk_get_int(ctx, -1);
                        DUK_ASSERT(varmap_value >= 0);
                }
                duk_pop(ctx);

#if 0
                /* It'd be nice to do something like this - but it doesn't
                 * work for closures created inside the catch clause.
                 */
                duk_dup_top(ctx);
                duk_push_int(ctx, (duk_int_t) (reg_catch + 0));
                duk_put_prop(ctx, comp_ctx->curr_func.varmap_idx);
#endif
                duk_dup_top(ctx);
                duk_push_null(ctx);
                duk_put_prop(ctx, comp_ctx->curr_func.varmap_idx);

                duk__emit_a_bc(comp_ctx,
                               DUK_OP_PUTVAR | DUK__EMIT_FLAG_A_IS_SOURCE,
                               (duk_regconst_t) (reg_catch + 0) /*value*/,
                               rc_varname /*varname*/);

                DUK_DDD(DUK_DDDPRINT("varmap before parsing catch clause: %!iT",
                                     (duk_tval *) duk_get_tval(ctx, comp_ctx->curr_func.varmap_idx)));

                duk__parse_stmts(comp_ctx, 0 /*allow_source_elem*/, 0 /*expect_eof*/);
                /* the DUK_TOK_RCURLY is eaten by duk__parse_stmts() */

                if (varmap_value == -2) {
                        /* not present */
                        duk_del_prop(ctx, comp_ctx->curr_func.varmap_idx);
                } else {
                        if (varmap_value == -1) {
                                duk_push_null(ctx);
                        } else {
                                DUK_ASSERT(varmap_value >= 0);
                                duk_push_int(ctx, varmap_value);
                        }
                        duk_put_prop(ctx, comp_ctx->curr_func.varmap_idx);
                }
                /* varname is popped by above code */

                DUK_DDD(DUK_DDDPRINT("varmap after restore catch clause: %!iT",
                                     (duk_tval *) duk_get_tval(ctx, comp_ctx->curr_func.varmap_idx)));

                duk__emit_extraop_only(comp_ctx,
                                       DUK_EXTRAOP_ENDCATCH);

                /*
                 *  XXX: for now, indicate that an expensive catch binding
                 *  declarative environment is always needed.  If we don't
                 *  need it, we don't need the const_varname either.
                 */

                trycatch_flags |= DUK_BC_TRYCATCH_FLAG_CATCH_BINDING;

                DUK_DDD(DUK_DDDPRINT("stack top at end of catch clause: %ld", (long) duk_get_top(ctx)));
        }

        if (comp_ctx->curr_token.t == DUK_TOK_FINALLY) {
                trycatch_flags |= DUK_BC_TRYCATCH_FLAG_HAVE_FINALLY;

                pc_finally = duk__get_current_pc(comp_ctx);

                duk__advance(comp_ctx);

                duk__advance_expect(comp_ctx, DUK_TOK_LCURLY);
                duk__parse_stmts(comp_ctx, 0 /*allow_source_elem*/, 0 /*expect_eof*/);
                /* the DUK_TOK_RCURLY is eaten by duk__parse_stmts() */
                duk__emit_extraop_b(comp_ctx,
                                    DUK_EXTRAOP_ENDFIN,
                                    reg_catch);  /* rethrow */
        }

        if (!(trycatch_flags & DUK_BC_TRYCATCH_FLAG_HAVE_CATCH) &&
            !(trycatch_flags & DUK_BC_TRYCATCH_FLAG_HAVE_FINALLY)) {
                /* must have catch and/or finally */
                goto syntax_error;
        }

        /* If there's no catch block, rc_varname will be 0 and duk__patch_trycatch()
         * will replace the LDCONST with a NOP.  For any actual constant (including
         * constant 0) the DUK__CONST_MARKER flag will be set in rc_varname.
         */

        duk__patch_trycatch(comp_ctx,
                            pc_ldconst,
                            pc_trycatch,
                            reg_catch,
                            rc_varname,
                            trycatch_flags);

        if (trycatch_flags & DUK_BC_TRYCATCH_FLAG_HAVE_CATCH) {
                DUK_ASSERT(pc_catch >= 0);
                duk__patch_jump(comp_ctx, pc_trycatch + 1, pc_catch);
        }

        if (trycatch_flags & DUK_BC_TRYCATCH_FLAG_HAVE_FINALLY) {
                DUK_ASSERT(pc_finally >= 0);
                duk__patch_jump(comp_ctx, pc_trycatch + 2, pc_finally);
        } else {
                /* without finally, the second jump slot is used to jump to end of stmt */
                duk__patch_jump_here(comp_ctx, pc_trycatch + 2);
        }

        comp_ctx->curr_func.catch_depth--;
        return;

 syntax_error:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_TRY);
}

DUK_LOCAL void duk__parse_with_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res) {
        duk_int_t pc_trycatch;
        duk_int_t pc_finished;
        duk_reg_t reg_catch;
        duk_small_uint_t trycatch_flags;

        if (comp_ctx->curr_func.is_strict) {
                DUK_ERROR_SYNTAX(comp_ctx->thr, DUK_STR_WITH_IN_STRICT_MODE);
        }

        comp_ctx->curr_func.catch_depth++;

        duk__advance(comp_ctx);  /* eat 'with' */

        reg_catch = DUK__ALLOCTEMPS(comp_ctx, 2);

        duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);
        duk__exprtop_toforcedreg(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/, reg_catch);
        duk__advance_expect(comp_ctx, DUK_TOK_RPAREN);

        pc_trycatch = duk__get_current_pc(comp_ctx);
        trycatch_flags = DUK_BC_TRYCATCH_FLAG_WITH_BINDING;
        duk__emit_a_bc(comp_ctx,
                        DUK_OP_TRYCATCH | DUK__EMIT_FLAG_NO_SHUFFLE_A,
                        (duk_regconst_t) trycatch_flags /*a*/,
                        (duk_regconst_t) reg_catch /*bc*/);
        duk__emit_invalid(comp_ctx);  /* catch jump */
        duk__emit_invalid(comp_ctx);  /* finished jump */

        duk__parse_stmt(comp_ctx, res, 0 /*allow_source_elem*/);
        duk__emit_extraop_only(comp_ctx,
                               DUK_EXTRAOP_ENDTRY);

        pc_finished = duk__get_current_pc(comp_ctx);

        duk__patch_jump(comp_ctx, pc_trycatch + 2, pc_finished);

        comp_ctx->curr_func.catch_depth--;
}

DUK_LOCAL duk_int_t duk__stmt_label_site(duk_compiler_ctx *comp_ctx, duk_int_t label_id) {
        /* if a site already exists, nop: max one label site per statement */
        if (label_id >= 0) {
                return label_id;
        }

        label_id = comp_ctx->curr_func.label_next++;
        DUK_DDD(DUK_DDDPRINT("allocated new label id for label site: %ld", (long) label_id));

        duk__emit_extraop_bc(comp_ctx,
                             DUK_EXTRAOP_LABEL,
                             (duk_regconst_t) label_id);
        duk__emit_invalid(comp_ctx);
        duk__emit_invalid(comp_ctx);

        return label_id;
}

/* Parse a single statement.
 *
 * Creates a label site (with an empty label) automatically for iteration
 * statements.  Also "peels off" any label statements for explicit labels.
 */
DUK_LOCAL void duk__parse_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *res, duk_bool_t allow_source_elem) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_bool_t dir_prol_at_entry;    /* directive prologue status at entry */
        duk_reg_t temp_at_entry;
        duk_uarridx_t labels_len_at_entry;
        duk_int_t pc_at_entry;           /* assumed to also be PC of "LABEL" */
        duk_int_t stmt_id;
        duk_small_uint_t stmt_flags = 0;
        duk_int_t label_id = -1;
        duk_small_uint_t tok;

        DUK__RECURSION_INCREASE(comp_ctx, thr);

        temp_at_entry = DUK__GETTEMP(comp_ctx);
        pc_at_entry = duk__get_current_pc(comp_ctx);
        labels_len_at_entry = (duk_uarridx_t) duk_get_length(ctx, comp_ctx->curr_func.labelnames_idx);
        stmt_id = comp_ctx->curr_func.stmt_next++;
        dir_prol_at_entry = comp_ctx->curr_func.in_directive_prologue;

        DUK_UNREF(stmt_id);

        DUK_DDD(DUK_DDDPRINT("parsing a statement, stmt_id=%ld, temp_at_entry=%ld, labels_len_at_entry=%ld, "
                             "is_strict=%ld, in_directive_prologue=%ld, catch_depth=%ld",
                             (long) stmt_id, (long) temp_at_entry, (long) labels_len_at_entry,
                             (long) comp_ctx->curr_func.is_strict, (long) comp_ctx->curr_func.in_directive_prologue,
                             (long) comp_ctx->curr_func.catch_depth));

        /* The directive prologue flag is cleared by default so that it is
         * unset for any recursive statement parsing.  It is only "revived"
         * if a directive is detected.  (We could also make directives only
         * allowed if 'allow_source_elem' was true.)
         */
        comp_ctx->curr_func.in_directive_prologue = 0;

 retry_parse:

        DUK_DDD(DUK_DDDPRINT("try stmt parse, stmt_id=%ld, label_id=%ld, allow_source_elem=%ld, catch_depth=%ld",
                             (long) stmt_id, (long) label_id, (long) allow_source_elem,
                             (long) comp_ctx->curr_func.catch_depth));

        /*
         *  Detect iteration statements; if encountered, establish an
         *  empty label.
         */

        tok = comp_ctx->curr_token.t;
        if (tok == DUK_TOK_FOR || tok == DUK_TOK_DO || tok == DUK_TOK_WHILE ||
            tok == DUK_TOK_SWITCH) {
                DUK_DDD(DUK_DDDPRINT("iteration/switch statement -> add empty label"));

                label_id = duk__stmt_label_site(comp_ctx, label_id);
                duk__add_label(comp_ctx,
                               DUK_HTHREAD_STRING_EMPTY_STRING(thr),
                               pc_at_entry /*pc_label*/,
                               label_id);
        }

        /*
         *  Main switch for statement / source element type.
         */

        switch (comp_ctx->curr_token.t) {
        case DUK_TOK_FUNCTION: {
                /*
                 *  Function declaration, function expression, or (non-standard)
                 *  function statement.
                 *
                 *  The E5 specification only allows function declarations at
                 *  the top level (in "source elements").  An ExpressionStatement
                 *  is explicitly not allowed to begin with a "function" keyword
                 *  (E5 Section 12.4).  Hence any non-error semantics for such
                 *  non-top-level statements are non-standard.  Duktape semantics
                 *  for function statements are modelled after V8, see
                 *  test-dev-func-decl-outside-top.js.
                 */

#if defined(DUK_USE_NONSTD_FUNC_STMT)
                /* Lenient: allow function declarations outside top level in
                 * non-strict mode but reject them in strict mode.
                 */
                if (allow_source_elem || !comp_ctx->curr_func.is_strict)
#else  /* DUK_USE_NONSTD_FUNC_STMT */
                /* Strict: never allow function declarations outside top level. */
                if (allow_source_elem)
#endif  /* DUK_USE_NONSTD_FUNC_STMT */
                {
                        /* FunctionDeclaration: not strictly a statement but handled as such.
                         *
                         * O(depth^2) parse count for inner functions is handled by recording a
                         * lexer offset on the first compilation pass, so that the function can
                         * be efficiently skipped on the second pass.  This is encapsulated into
                         * duk__parse_func_like_fnum().
                         */

                        duk_int_t fnum;

                        DUK_DDD(DUK_DDDPRINT("function declaration statement"));

                        duk__advance(comp_ctx);  /* eat 'function' */
                        fnum = duk__parse_func_like_fnum(comp_ctx, 1 /*is_decl*/, 0 /*is_setget*/);

                        if (comp_ctx->curr_func.in_scanning) {
                                duk_uarridx_t n;
                                duk_hstring *h_funcname;

                                duk_get_prop_index(ctx, comp_ctx->curr_func.funcs_idx, fnum * 3);
                                duk_get_prop_stridx(ctx, -1, DUK_STRIDX_NAME);  /* -> [ ... func name ] */
                                h_funcname = duk_get_hstring(ctx, -1);
                                DUK_ASSERT(h_funcname != NULL);

                                DUK_DDD(DUK_DDDPRINT("register function declaration %!O in pass 1, fnum %ld",
                                                     (duk_heaphdr *) h_funcname, (long) fnum));
                                n = (duk_uarridx_t) duk_get_length(ctx, comp_ctx->curr_func.decls_idx);
                                duk_push_hstring(ctx, h_funcname);
                                duk_put_prop_index(ctx, comp_ctx->curr_func.decls_idx, n);
                                duk_push_int(ctx, (duk_int_t) (DUK_DECL_TYPE_FUNC + (fnum << 8)));
                                duk_put_prop_index(ctx, comp_ctx->curr_func.decls_idx, n + 1);

                                duk_pop_n(ctx, 2);
                        }

                        /* no statement value (unlike function expression) */
                        stmt_flags = 0;
                        break;
                } else {
                        DUK_ERROR_SYNTAX(thr, DUK_STR_FUNC_STMT_NOT_ALLOWED);
                }
                break;
        }
        case DUK_TOK_LCURLY: {
                DUK_DDD(DUK_DDDPRINT("block statement"));
                duk__advance(comp_ctx);
                duk__parse_stmts(comp_ctx, 0 /*allow_source_elem*/, 0 /*expect_eof*/);
                /* the DUK_TOK_RCURLY is eaten by duk__parse_stmts() */
                if (label_id >= 0) {
                        duk__patch_jump_here(comp_ctx, pc_at_entry + 1);  /* break jump */
                }
                stmt_flags = 0;
                break;
        }
        case DUK_TOK_CONST: {
                DUK_DDD(DUK_DDDPRINT("constant declaration statement"));
                duk__parse_var_stmt(comp_ctx, res, DUK__EXPR_FLAG_REQUIRE_INIT /*expr_flags*/);
                stmt_flags = DUK__HAS_TERM;
                break;
        }
        case DUK_TOK_VAR: {
                DUK_DDD(DUK_DDDPRINT("variable declaration statement"));
                duk__parse_var_stmt(comp_ctx, res, 0 /*expr_flags*/);
                stmt_flags = DUK__HAS_TERM;
                break;
        }
        case DUK_TOK_SEMICOLON: {
                /* empty statement with an explicit semicolon */
                DUK_DDD(DUK_DDDPRINT("empty statement"));
                stmt_flags = DUK__HAS_TERM;
                break;
        }
        case DUK_TOK_IF: {
                DUK_DDD(DUK_DDDPRINT("if statement"));
                duk__parse_if_stmt(comp_ctx, res);
                if (label_id >= 0) {
                        duk__patch_jump_here(comp_ctx, pc_at_entry + 1);  /* break jump */
                }
                stmt_flags = 0;
                break;
        }
        case DUK_TOK_DO: {
                /*
                 *  Do-while statement is mostly trivial, but there is special
                 *  handling for automatic semicolon handling (triggered by the
                 *  DUK__ALLOW_AUTO_SEMI_ALWAYS) flag related to a bug filed at:
                 *
                 *    https://bugs.ecmascript.org/show_bug.cgi?id=8
                 *
                 *  See doc/compiler.rst for details.
                 */
                DUK_DDD(DUK_DDDPRINT("do statement"));
                DUK_ASSERT(label_id >= 0);
                duk__update_label_flags(comp_ctx,
                                        label_id,
                                        DUK_LABEL_FLAG_ALLOW_BREAK | DUK_LABEL_FLAG_ALLOW_CONTINUE);
                duk__parse_do_stmt(comp_ctx, res, pc_at_entry);
                stmt_flags = DUK__HAS_TERM | DUK__ALLOW_AUTO_SEMI_ALWAYS;  /* DUK__ALLOW_AUTO_SEMI_ALWAYS workaround */
                break;
        }
        case DUK_TOK_WHILE: {
                DUK_DDD(DUK_DDDPRINT("while statement"));
                DUK_ASSERT(label_id >= 0);
                duk__update_label_flags(comp_ctx,
                                        label_id,
                                        DUK_LABEL_FLAG_ALLOW_BREAK | DUK_LABEL_FLAG_ALLOW_CONTINUE);
                duk__parse_while_stmt(comp_ctx, res, pc_at_entry);
                stmt_flags = 0;
                break;
        }
        case DUK_TOK_FOR: {
                /*
                 *  For/for-in statement is complicated to parse because
                 *  determining the statement type (three-part for vs. a
                 *  for-in) requires potential backtracking.
                 *
                 *  See the helper for the messy stuff.
                 */
                DUK_DDD(DUK_DDDPRINT("for/for-in statement"));
                DUK_ASSERT(label_id >= 0);
                duk__update_label_flags(comp_ctx,
                                        label_id,
                                        DUK_LABEL_FLAG_ALLOW_BREAK | DUK_LABEL_FLAG_ALLOW_CONTINUE);
                duk__parse_for_stmt(comp_ctx, res, pc_at_entry);
                stmt_flags = 0;
                break;
        }
        case DUK_TOK_CONTINUE:
        case DUK_TOK_BREAK: {
                DUK_DDD(DUK_DDDPRINT("break/continue statement"));
                duk__parse_break_or_continue_stmt(comp_ctx, res);
                stmt_flags = DUK__HAS_TERM | DUK__IS_TERMINAL;
                break;
        }
        case DUK_TOK_RETURN: {
                DUK_DDD(DUK_DDDPRINT("return statement"));
                duk__parse_return_stmt(comp_ctx, res);
                stmt_flags = DUK__HAS_TERM | DUK__IS_TERMINAL;
                break;
        }
        case DUK_TOK_WITH: {
                DUK_DDD(DUK_DDDPRINT("with statement"));
                comp_ctx->curr_func.with_depth++;
                duk__parse_with_stmt(comp_ctx, res);
                if (label_id >= 0) {
                        duk__patch_jump_here(comp_ctx, pc_at_entry + 1);  /* break jump */
                }
                comp_ctx->curr_func.with_depth--;
                stmt_flags = 0;
                break;
        }
        case DUK_TOK_SWITCH: {
                /*
                 *  The switch statement is pretty messy to compile.
                 *  See the helper for details.
                 */
                DUK_DDD(DUK_DDDPRINT("switch statement"));
                DUK_ASSERT(label_id >= 0);
                duk__update_label_flags(comp_ctx,
                                        label_id,
                                        DUK_LABEL_FLAG_ALLOW_BREAK);  /* don't allow continue */
                duk__parse_switch_stmt(comp_ctx, res, pc_at_entry);
                stmt_flags = 0;
                break;
        }
        case DUK_TOK_THROW: {
                DUK_DDD(DUK_DDDPRINT("throw statement"));
                duk__parse_throw_stmt(comp_ctx, res);
                stmt_flags = DUK__HAS_TERM | DUK__IS_TERMINAL;
                break;
        }
        case DUK_TOK_TRY: {
                DUK_DDD(DUK_DDDPRINT("try statement"));
                duk__parse_try_stmt(comp_ctx, res);
                stmt_flags = 0;
                break;
        }
        case DUK_TOK_DEBUGGER: {
                duk__advance(comp_ctx);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
                DUK_DDD(DUK_DDDPRINT("debugger statement: debugging enabled, emit debugger opcode"));
                duk__emit_extraop_only(comp_ctx, DUK_EXTRAOP_DEBUGGER);
#else
                DUK_DDD(DUK_DDDPRINT("debugger statement: ignored"));
#endif
                stmt_flags = DUK__HAS_TERM;
                break;
        }
        default: {
                /*
                 *  Else, must be one of:
                 *    - ExpressionStatement, possibly a directive (String)
                 *    - LabelledStatement (Identifier followed by ':')
                 *
                 *  Expressions beginning with 'function' keyword are covered by a case
                 *  above (such expressions are not allowed in standard E5 anyway).
                 *  Also expressions starting with '{' are interpreted as block
                 *  statements.  See E5 Section 12.4.
                 *
                 *  Directive detection is tricky; see E5 Section 14.1 on directive
                 *  prologue.  A directive is an expression statement with a single
                 *  string literal and an explicit or automatic semicolon.  Escape
                 *  characters are significant and no parens etc are allowed:
                 *
                 *    'use strict';          // valid 'use strict' directive
                 *    'use\u0020strict';     // valid directive, not a 'use strict' directive
                 *    ('use strict');        // not a valid directive
                 *
                 *  The expression is determined to consist of a single string literal
                 *  based on duk__expr_nud() and duk__expr_led() call counts.  The string literal
                 *  of a 'use strict' directive is determined to lack any escapes based
                 *  num_escapes count from the lexer.  Note that other directives may be
                 *  allowed to contain escapes, so a directive with escapes does not
                 *  terminate a directive prologue.
                 *
                 *  We rely on the fact that the expression parser will not emit any
                 *  code for a single token expression.  However, it will generate an
                 *  intermediate value which we will then successfully ignore.
                 *
                 *  A similar approach is used for labels.
                 */

                duk_bool_t single_token;

                DUK_DDD(DUK_DDDPRINT("expression statement"));
                duk__exprtop(comp_ctx, res, DUK__BP_FOR_EXPR /*rbp_flags*/);

                single_token = (comp_ctx->curr_func.nud_count == 1 &&  /* one token */
                                comp_ctx->curr_func.led_count == 0);   /* no operators */

                if (single_token &&
                    comp_ctx->prev_token.t == DUK_TOK_IDENTIFIER &&
                    comp_ctx->curr_token.t == DUK_TOK_COLON) {
                        /*
                         *  Detected label
                         */

                        duk_hstring *h_lab;

                        /* expected ival */
                        DUK_ASSERT(res->t == DUK_IVAL_VAR);
                        DUK_ASSERT(res->x1.t == DUK_ISPEC_VALUE);
                        DUK_ASSERT(DUK_TVAL_IS_STRING(duk_get_tval(ctx, res->x1.valstack_idx)));
                        h_lab = comp_ctx->prev_token.str1;
                        DUK_ASSERT(h_lab != NULL);

                        DUK_DDD(DUK_DDDPRINT("explicit label site for label '%!O'",
                                             (duk_heaphdr *) h_lab));

                        duk__advance(comp_ctx);  /* eat colon */

                        label_id = duk__stmt_label_site(comp_ctx, label_id);

                        duk__add_label(comp_ctx,
                                       h_lab,
                                       pc_at_entry /*pc_label*/,
                                       label_id);

                        /* a statement following a label cannot be a source element
                         * (a function declaration).
                         */
                        allow_source_elem = 0;

                        DUK_DDD(DUK_DDDPRINT("label handled, retry statement parsing"));
                        goto retry_parse;
                }

                stmt_flags = 0;

                if (dir_prol_at_entry &&                           /* still in prologue */
                    single_token &&                                /* single string token */
                    comp_ctx->prev_token.t == DUK_TOK_STRING) {
                        /*
                         *  Detected a directive
                         */
                        duk_hstring *h_dir;

                        /* expected ival */
                        DUK_ASSERT(res->t == DUK_IVAL_PLAIN);
                        DUK_ASSERT(res->x1.t == DUK_ISPEC_VALUE);
                        DUK_ASSERT(DUK_TVAL_IS_STRING(duk_get_tval(ctx, res->x1.valstack_idx)));
                        h_dir = comp_ctx->prev_token.str1;
                        DUK_ASSERT(h_dir != NULL);

                        DUK_DDD(DUK_DDDPRINT("potential directive: %!O", h_dir));

                        stmt_flags |= DUK__STILL_PROLOGUE;

                        /* Note: escaped characters differentiate directives */

                        if (comp_ctx->prev_token.num_escapes > 0) {
                                DUK_DDD(DUK_DDDPRINT("directive contains escapes: valid directive "
                                                     "but we ignore such directives"));
                        } else {
                                /*
                                 * The length comparisons are present to handle
                                 * strings like "use strict\u0000foo" as required.
                                 */

                                if (DUK_HSTRING_GET_BYTELEN(h_dir) == 10 &&
                                    DUK_STRNCMP((const char *) DUK_HSTRING_GET_DATA(h_dir), "use strict", 10) == 0) {
#if defined(DUK_USE_STRICT_DECL)
                                        DUK_DDD(DUK_DDDPRINT("use strict directive detected: strict flag %ld -> %ld",
                                                             (long) comp_ctx->curr_func.is_strict, (long) 1));
                                        comp_ctx->curr_func.is_strict = 1;
#else
                                        DUK_DDD(DUK_DDDPRINT("use strict detected but strict declarations disabled, ignoring"));
#endif
                                } else if (DUK_HSTRING_GET_BYTELEN(h_dir) == 14 &&
                                           DUK_STRNCMP((const char *) DUK_HSTRING_GET_DATA(h_dir), "use duk notail", 14) == 0) {
                                        DUK_DDD(DUK_DDDPRINT("use duk notail directive detected: notail flag %ld -> %ld",
                                                             (long) comp_ctx->curr_func.is_notail, (long) 1));
                                        comp_ctx->curr_func.is_notail = 1;
                                } else {
                                        DUK_DD(DUK_DDPRINT("unknown directive: '%!O', ignoring but not terminating "
                                                           "directive prologue", (duk_hobject *) h_dir));
                                }
                        }
                } else {
                        DUK_DDD(DUK_DDDPRINT("non-directive expression statement or no longer in prologue; "
                                             "prologue terminated if still active"));
                }

                stmt_flags |= DUK__HAS_VAL | DUK__HAS_TERM;
        }
        }  /* end switch (tok) */

        /*
         *  Statement value handling.
         *
         *  Global code and eval code has an implicit return value
         *  which comes from the last statement with a value
         *  (technically a non-"empty" continuation, which is
         *  different from an empty statement).
         *
         *  Since we don't know whether a later statement will
         *  override the value of the current statement, we need
         *  to coerce the statement value to a register allocated
         *  for implicit return values.  In other cases we need
         *  to coerce the statement value to a plain value to get
         *  any side effects out (consider e.g. "foo.bar;").
         */

        /* XXX: what about statements which leave a half-cooked value in 'res'
         * but have no stmt value?  Any such statements?
         */

        if (stmt_flags & DUK__HAS_VAL) {
                duk_reg_t reg_stmt_value = comp_ctx->curr_func.reg_stmt_value;
                if (reg_stmt_value >= 0) {
                        duk__ivalue_toforcedreg(comp_ctx, res, reg_stmt_value);
                } else {
                        duk__ivalue_toplain_ignore(comp_ctx, res);
                }
        } else {
                ;
        }

        /*
         *  Statement terminator check, including automatic semicolon
         *  handling.  After this step, 'curr_tok' should be the first
         *  token after a possible statement terminator.
         */

        if (stmt_flags & DUK__HAS_TERM) {
                if (comp_ctx->curr_token.t == DUK_TOK_SEMICOLON) {
                        DUK_DDD(DUK_DDDPRINT("explicit semicolon terminates statement"));
                        duk__advance(comp_ctx);
                } else {
                        if (comp_ctx->curr_token.allow_auto_semi) {
                                DUK_DDD(DUK_DDDPRINT("automatic semicolon terminates statement"));
                        } else if (stmt_flags & DUK__ALLOW_AUTO_SEMI_ALWAYS) {
                                /* XXX: make this lenience dependent on flags or strictness? */
                                DUK_DDD(DUK_DDDPRINT("automatic semicolon terminates statement (allowed for compatibility "
                                                     "even though no lineterm present before next token)"));
                        } else {
                                DUK_ERROR_SYNTAX(thr, DUK_STR_UNTERMINATED_STMT);
                        }
                }
        } else {
                DUK_DDD(DUK_DDDPRINT("statement has no terminator"));
        }

        /*
         *  Directive prologue tracking.
         */

        if (stmt_flags & DUK__STILL_PROLOGUE) {
                DUK_DDD(DUK_DDDPRINT("setting in_directive_prologue"));
                comp_ctx->curr_func.in_directive_prologue = 1;
        }

        /*
         *  Cleanups (all statement parsing flows through here).
         *
         *  Pop label site and reset labels.  Reset 'next temp' to value at
         *  entry to reuse temps.
         */

        if (label_id >= 0) {
                duk__emit_extraop_bc(comp_ctx,
                                     DUK_EXTRAOP_ENDLABEL,
                                     (duk_regconst_t) label_id);
        }

        DUK__SETTEMP(comp_ctx, temp_at_entry);

        duk__reset_labels_to_length(comp_ctx, labels_len_at_entry);

        /* XXX: return indication of "terminalness" (e.g. a 'throw' is terminal) */

        DUK__RECURSION_DECREASE(comp_ctx, thr);
}

#undef DUK__HAS_VAL
#undef DUK__HAS_TERM
#undef DUK__ALLOW_AUTO_SEMI_ALWAYS

/*
 *  Parse a statement list.
 *
 *  Handles automatic semicolon insertion and implicit return value.
 *
 *  Upon entry, 'curr_tok' should contain the first token of the first
 *  statement (parsed in the "allow regexp literal" mode).  Upon exit,
 *  'curr_tok' contains the token following the statement list terminator
 *  (EOF or closing brace).
 */

DUK_LOCAL void duk__parse_stmts(duk_compiler_ctx *comp_ctx, duk_bool_t allow_source_elem, duk_bool_t expect_eof) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_ivalue res_alloc;
        duk_ivalue *res = &res_alloc;

        /* Setup state.  Initial ivalue is 'undefined'. */

        duk_require_stack(ctx, DUK__PARSE_STATEMENTS_SLOTS);

        /* XXX: 'res' setup can be moved to function body level; in fact, two 'res'
         * intermediate values suffice for parsing of each function.  Nesting is needed
         * for nested functions (which may occur inside expressions).
         */

        DUK_MEMZERO(&res_alloc, sizeof(res_alloc));
        res->t = DUK_IVAL_PLAIN;
        res->x1.t = DUK_ISPEC_VALUE;
        res->x1.valstack_idx = duk_get_top(ctx);
        res->x2.valstack_idx = res->x1.valstack_idx + 1;
        duk_push_undefined(ctx);
        duk_push_undefined(ctx);

        /* Parse statements until a closing token (EOF or '}') is found. */

        for (;;) {
                /* Check whether statement list ends. */

                if (expect_eof) {
                        if (comp_ctx->curr_token.t == DUK_TOK_EOF) {
                                break;
                        }
                } else {
                        if (comp_ctx->curr_token.t == DUK_TOK_RCURLY) {
                                break;
                        }
                }

                /* Check statement type based on the first token type.
                 *
                 * Note: expression parsing helpers expect 'curr_tok' to
                 * contain the first token of the expression upon entry.
                 */

                DUK_DDD(DUK_DDDPRINT("TOKEN %ld (non-whitespace, non-comment)", (long) comp_ctx->curr_token.t));

                duk__parse_stmt(comp_ctx, res, allow_source_elem);
        }

        duk__advance(comp_ctx);

        /* Tear down state. */

        duk_pop_2(ctx);
}

/*
 *  Declaration binding instantiation conceptually happens when calling a
 *  function; for us it essentially means that function prologue.  The
 *  conceptual process is described in E5 Section 10.5.
 *
 *  We need to keep track of all encountered identifiers to (1) create an
 *  identifier-to-register map ("varmap"); and (2) detect duplicate
 *  declarations.  Identifiers which are not bound to registers still need
 *  to be tracked for detecting duplicates.  Currently such identifiers
 *  are put into the varmap with a 'null' value, which is later cleaned up.
 *
 *  To support functions with a large number of variable and function
 *  declarations, registers are not allocated beyond a certain limit;
 *  after that limit, variables and functions need slow path access.
 *  Arguments are currently always register bound, which imposes a hard
 *  (and relatively small) argument count limit.
 *
 *  Some bindings in E5 are not configurable (= deletable) and almost all
 *  are mutable (writable).  Exceptions are:
 *
 *    - The 'arguments' binding, established only if no shadowing argument
 *      or function declaration exists.  We handle 'arguments' creation
 *      and binding through an explicit slow path environment record.
 *
 *    - The "name" binding for a named function expression.  This is also
 *      handled through an explicit slow path environment record.
 */

/* XXX: add support for variables to not be register bound always, to
 * handle cases with a very large number of variables?
 */

DUK_LOCAL void duk__init_varmap_and_prologue_for_pass2(duk_compiler_ctx *comp_ctx, duk_reg_t *out_stmt_value_reg) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_hstring *h_name;
        duk_bool_t configurable_bindings;
        duk_uarridx_t num_args;
        duk_uarridx_t num_decls;
        duk_regconst_t rc_name;
        duk_small_uint_t declvar_flags;
        duk_uarridx_t i;
#ifdef DUK_USE_ASSERTIONS
        duk_idx_t entry_top;
#endif

#ifdef DUK_USE_ASSERTIONS
        entry_top = duk_get_top(ctx);
#endif

        /*
         *  Preliminaries
         */

        configurable_bindings = comp_ctx->curr_func.is_eval;
        DUK_DDD(DUK_DDDPRINT("configurable_bindings=%ld", (long) configurable_bindings));

        /* varmap is already in comp_ctx->curr_func.varmap_idx */

        /*
         *  Function formal arguments, always bound to registers
         *  (there's no support for shuffling them now).
         */

        num_args = (duk_uarridx_t) duk_get_length(ctx, comp_ctx->curr_func.argnames_idx);
        DUK_DDD(DUK_DDDPRINT("num_args=%ld", (long) num_args));
        /* XXX: check num_args */

        for (i = 0; i < num_args; i++) {
                duk_get_prop_index(ctx, comp_ctx->curr_func.argnames_idx, i);
                h_name = duk_get_hstring(ctx, -1);
                DUK_ASSERT(h_name != NULL);

                if (comp_ctx->curr_func.is_strict) {
                        if (duk__hstring_is_eval_or_arguments(comp_ctx, h_name)) {
                                DUK_DDD(DUK_DDDPRINT("arg named 'eval' or 'arguments' in strict mode -> SyntaxError"));
                                goto error_argname;
                        }
                        duk_dup_top(ctx);
                        if (duk_has_prop(ctx, comp_ctx->curr_func.varmap_idx)) {
                                DUK_DDD(DUK_DDDPRINT("duplicate arg name in strict mode -> SyntaxError"));
                                goto error_argname;
                        }

                        /* Ensure argument name is not a reserved word in current
                         * (final) strictness.  Formal argument parsing may not
                         * catch reserved names if strictness changes during
                         * parsing.
                         *
                         * We only need to do this in strict mode because non-strict
                         * keyword are always detected in formal argument parsing.
                         */

                        if (DUK_HSTRING_HAS_STRICT_RESERVED_WORD(h_name)) {
                                goto error_argname;
                        }
                }

                /* overwrite any previous binding of the same name; the effect is
                 * that last argument of a certain name wins.
                 */

                /* only functions can have arguments */
                DUK_ASSERT(comp_ctx->curr_func.is_function);
                duk_push_uarridx(ctx, i);  /* -> [ ... name index ] */
                duk_put_prop(ctx, comp_ctx->curr_func.varmap_idx); /* -> [ ... ] */

                /* no code needs to be emitted, the regs already have values */
        }

        /* use temp_next for tracking register allocations */
        DUK__SETTEMP_CHECKMAX(comp_ctx, (duk_reg_t) num_args);

        /*
         *  After arguments, allocate special registers (like shuffling temps)
         */

        if (out_stmt_value_reg) {
                *out_stmt_value_reg = DUK__ALLOCTEMP(comp_ctx);
        }
        if (comp_ctx->curr_func.needs_shuffle) {
                duk_reg_t shuffle_base = DUK__ALLOCTEMPS(comp_ctx, 3);
                comp_ctx->curr_func.shuffle1 = shuffle_base;
                comp_ctx->curr_func.shuffle2 = shuffle_base + 1;
                comp_ctx->curr_func.shuffle3 = shuffle_base + 2;
                DUK_D(DUK_DPRINT("shuffle registers needed by function, allocated: %ld %ld %ld",
                                 (long) comp_ctx->curr_func.shuffle1,
                                 (long) comp_ctx->curr_func.shuffle2,
                                 (long) comp_ctx->curr_func.shuffle3));
        }
        if (comp_ctx->curr_func.temp_next > 0x100) {
                DUK_D(DUK_DPRINT("not enough 8-bit regs: temp_next=%ld", (long) comp_ctx->curr_func.temp_next));
                goto error_outofregs;
        }

        /*
         *  Function declarations
         */

        num_decls = (duk_uarridx_t) duk_get_length(ctx, comp_ctx->curr_func.decls_idx);
        DUK_DDD(DUK_DDDPRINT("num_decls=%ld -> %!T",
                             (long) num_decls,
                             (duk_tval *) duk_get_tval(ctx, comp_ctx->curr_func.decls_idx)));
        for (i = 0; i < num_decls; i += 2) {
                duk_int_t decl_type;
                duk_int_t fnum;

                duk_get_prop_index(ctx, comp_ctx->curr_func.decls_idx, i + 1);  /* decl type */
                decl_type = duk_to_int(ctx, -1);
                fnum = decl_type >> 8;  /* XXX: macros */
                decl_type = decl_type & 0xff;
                duk_pop(ctx);

                if (decl_type != DUK_DECL_TYPE_FUNC) {
                        continue;
                }

                duk_get_prop_index(ctx, comp_ctx->curr_func.decls_idx, i);  /* decl name */

                /* XXX: spilling */
                if (comp_ctx->curr_func.is_function) {
                        duk_reg_t reg_bind;
                        duk_dup_top(ctx);
                        if (duk_has_prop(ctx, comp_ctx->curr_func.varmap_idx)) {
                                /* shadowed; update value */
                                duk_dup_top(ctx);
                                duk_get_prop(ctx, comp_ctx->curr_func.varmap_idx);
                                reg_bind = duk_to_int(ctx, -1);  /* [ ... name reg_bind ] */
                                duk__emit_a_bc(comp_ctx,
                                               DUK_OP_CLOSURE,
                                               (duk_regconst_t) reg_bind,
                                               (duk_regconst_t) fnum);
                        } else {
                                /* function: always register bound */
                                reg_bind = DUK__ALLOCTEMP(comp_ctx);
                                duk__emit_a_bc(comp_ctx,
                                               DUK_OP_CLOSURE,
                                               (duk_regconst_t) reg_bind,
                                               (duk_regconst_t) fnum);
                                duk_push_int(ctx, (duk_int_t) reg_bind);
                        }
                } else {
                        /* Function declaration for global/eval code is emitted even
                         * for duplicates, because of E5 Section 10.5, step 5.e of
                         * E5.1 (special behavior for variable bound to global object).
                         *
                         * DECLVAR will not re-declare a variable as such, but will
                         * update the binding value.
                         */

                        duk_reg_t reg_temp = DUK__ALLOCTEMP(comp_ctx);
                        duk_dup_top(ctx);
                        rc_name = duk__getconst(comp_ctx);
                        duk_push_null(ctx);

                        duk__emit_a_bc(comp_ctx,
                                       DUK_OP_CLOSURE,
                                       (duk_regconst_t) reg_temp,
                                       (duk_regconst_t) fnum);

                        declvar_flags = DUK_PROPDESC_FLAG_WRITABLE |
                                        DUK_PROPDESC_FLAG_ENUMERABLE |
                                        DUK_BC_DECLVAR_FLAG_FUNC_DECL;

                        if (configurable_bindings) {
                                declvar_flags |= DUK_PROPDESC_FLAG_CONFIGURABLE;
                        }

                        duk__emit_a_b_c(comp_ctx,
                                        DUK_OP_DECLVAR | DUK__EMIT_FLAG_NO_SHUFFLE_A,
                                        (duk_regconst_t) declvar_flags /*flags*/,
                                        rc_name /*name*/,
                                        (duk_regconst_t) reg_temp /*value*/);

                        DUK__SETTEMP(comp_ctx, reg_temp);  /* forget temp */
                }

                DUK_DDD(DUK_DDDPRINT("function declaration to varmap: %!T -> %!T",
                                     (duk_tval *) duk_get_tval(ctx, -2),
                                     (duk_tval *) duk_get_tval(ctx, -1)));

                duk_put_prop(ctx, comp_ctx->curr_func.varmap_idx);  /* [ ... name reg/null ] -> [ ... ] */
        }

        /*
         *  'arguments' binding is special; if a shadowing argument or
         *  function declaration exists, an arguments object will
         *  definitely not be needed, regardless of whether the identifier
         *  'arguments' is referenced inside the function body.
         */

        if (duk_has_prop_stridx(ctx, comp_ctx->curr_func.varmap_idx, DUK_STRIDX_LC_ARGUMENTS)) {
                DUK_DDD(DUK_DDDPRINT("'arguments' is shadowed by argument or function declaration "
                                     "-> arguments object creation can be skipped"));
                comp_ctx->curr_func.is_arguments_shadowed = 1;
        }

        /*
         *  Variable declarations.
         *
         *  Unlike function declarations, variable declaration values don't get
         *  assigned on entry.  If a binding of the same name already exists, just
         *  ignore it silently.
         */

        for (i = 0; i < num_decls; i += 2) {
                duk_int_t decl_type;

                duk_get_prop_index(ctx, comp_ctx->curr_func.decls_idx, i + 1);  /* decl type */
                decl_type = duk_to_int(ctx, -1);
                decl_type = decl_type & 0xff;
                duk_pop(ctx);

                if (decl_type != DUK_DECL_TYPE_VAR) {
                        continue;
                }

                duk_get_prop_index(ctx, comp_ctx->curr_func.decls_idx, i);  /* decl name */

                if (duk_has_prop(ctx, comp_ctx->curr_func.varmap_idx)) {
                        /* shadowed, ignore */
                } else {
                        duk_get_prop_index(ctx, comp_ctx->curr_func.decls_idx, i);  /* decl name */
                        h_name = duk_get_hstring(ctx, -1);
                        DUK_ASSERT(h_name != NULL);

                        if (h_name == DUK_HTHREAD_STRING_LC_ARGUMENTS(thr) &&
                            !comp_ctx->curr_func.is_arguments_shadowed) {
                                /* E5 Section steps 7-8 */
                                DUK_DDD(DUK_DDDPRINT("'arguments' not shadowed by a function declaration, "
                                                     "but appears as a variable declaration -> treat as "
                                                     "a no-op for variable declaration purposes"));
                                duk_pop(ctx);
                                continue;
                        }

                        /* XXX: spilling */
                        if (comp_ctx->curr_func.is_function) {
                                duk_reg_t reg_bind = DUK__ALLOCTEMP(comp_ctx);
                                /* no need to init reg, it will be undefined on entry */
                                duk_push_int(ctx, (duk_int_t) reg_bind);
                        } else {
                                duk_dup_top(ctx);
                                rc_name = duk__getconst(comp_ctx);
                                duk_push_null(ctx);

                                declvar_flags = DUK_PROPDESC_FLAG_WRITABLE |
                                                DUK_PROPDESC_FLAG_ENUMERABLE |
                                                DUK_BC_DECLVAR_FLAG_UNDEF_VALUE;
                                if (configurable_bindings) {
                                        declvar_flags |= DUK_PROPDESC_FLAG_CONFIGURABLE;
                                }

                                duk__emit_a_b_c(comp_ctx,
                                                DUK_OP_DECLVAR | DUK__EMIT_FLAG_NO_SHUFFLE_A,
                                                (duk_regconst_t) declvar_flags /*flags*/,
                                                rc_name /*name*/,
                                                (duk_regconst_t) 0 /*value*/);
                        }

                        duk_put_prop(ctx, comp_ctx->curr_func.varmap_idx);  /* [ ... name reg/null ] -> [ ... ] */
                }
        }

        /*
         *  Wrap up
         */

        DUK_DDD(DUK_DDDPRINT("varmap: %!T, is_arguments_shadowed=%ld",
                             (duk_tval *) duk_get_tval(ctx, comp_ctx->curr_func.varmap_idx),
                             (long) comp_ctx->curr_func.is_arguments_shadowed));

        DUK_ASSERT_TOP(ctx, entry_top);
        return;

 error_outofregs:
        DUK_ERROR_RANGE(thr, DUK_STR_REG_LIMIT);
        DUK_UNREACHABLE();
        return;

 error_argname:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_ARG_NAME);
        DUK_UNREACHABLE();
        return;
}

/*
 *  Parse a function-body-like expression (FunctionBody or Program
 *  in E5 grammar) using a two-pass parse.  The productions appear
 *  in the following contexts:
 *
 *    - function expression
 *    - function statement
 *    - function declaration
 *    - getter in object literal
 *    - setter in object literal
 *    - global code
 *    - eval code
 *    - Function constructor body
 *
 *  This function only parses the statement list of the body; the argument
 *  list and possible function name must be initialized by the caller.
 *  For instance, for Function constructor, the argument names are originally
 *  on the value stack.  The parsing of statements ends either at an EOF or
 *  a closing brace; this is controlled by an input flag.
 *
 *  Note that there are many differences affecting parsing and even code
 *  generation:
 *
 *    - Global and eval code have an implicit return value generated
 *      by the last statement; function code does not
 *
 *    - Global code, eval code, and Function constructor body end in
 *      an EOF, other bodies in a closing brace ('}')
 *
 *  Upon entry, 'curr_tok' is ignored and the function will pull in the
 *  first token on its own.  Upon exit, 'curr_tok' is the terminating
 *  token (EOF or closing brace).
 */

DUK_LOCAL void duk__parse_func_body(duk_compiler_ctx *comp_ctx, duk_bool_t expect_eof, duk_bool_t implicit_return_value, duk_small_int_t expect_token) {
        duk_compiler_func *func;
        duk_hthread *thr;
        duk_context *ctx;
        duk_reg_t reg_stmt_value = -1;
        duk_lexer_point lex_pt;
        duk_reg_t temp_first;
        duk_small_int_t compile_round = 1;

        DUK_ASSERT(comp_ctx != NULL);

        thr = comp_ctx->thr;
        ctx = (duk_context *) thr;
        DUK_ASSERT(thr != NULL);

        func = &comp_ctx->curr_func;
        DUK_ASSERT(func != NULL);

        DUK__RECURSION_INCREASE(comp_ctx, thr);

        duk_require_stack(ctx, DUK__FUNCTION_BODY_REQUIRE_SLOTS);

        /*
         *  Store lexer position for a later rewind
         */

        DUK_LEXER_GETPOINT(&comp_ctx->lex, &lex_pt);

        /*
         *  Program code (global and eval code) has an implicit return value
         *  from the last statement value (e.g. eval("1; 2+3;") returns 3).
         *  This is not the case with functions.  If implicit statement return
         *  value is requested, all statements are coerced to a register
         *  allocated here, and used in the implicit return statement below.
         */

        /* XXX: this is pointless here because pass 1 is throw-away */
        if (implicit_return_value) {
                reg_stmt_value = DUK__ALLOCTEMP(comp_ctx);

                /* If an implicit return value is needed by caller, it must be
                 * initialized to 'undefined' because we don't know whether any
                 * non-empty (where "empty" is a continuation type, and different
                 * from an empty statement) statements will be executed.
                 *
                 * However, since 1st pass is a throwaway one, no need to emit
                 * it here.
                 */
#if 0
                duk__emit_extraop_bc(comp_ctx,
                                     DUK_EXTRAOP_LDUNDEF,
                                     0);
#endif
        }

        /*
         *  First pass.
         *
         *  Gather variable/function declarations needed for second pass.
         *  Code generated is dummy and discarded.
         */

        func->in_directive_prologue = 1;
        func->in_scanning = 1;
        func->may_direct_eval = 0;
        func->id_access_arguments = 0;
        func->id_access_slow = 0;
        func->reg_stmt_value = reg_stmt_value;
#if defined(DUK_USE_DEBUGGER_SUPPORT)
        func->min_line = DUK_INT_MAX;
        func->max_line = 0;
#endif

        /* duk__parse_stmts() expects curr_tok to be set; parse in "allow regexp literal" mode with current strictness */
        if (expect_token >= 0) {
                /* Eating a left curly; regexp mode is allowed by left curly
                 * based on duk__token_lbp[] automatically.
                 */
                DUK_ASSERT(expect_token == DUK_TOK_LCURLY);
                duk__update_lineinfo_currtoken(comp_ctx);
                duk__advance_expect(comp_ctx, expect_token);
        } else {
                /* Need to set curr_token.t because lexing regexp mode depends on current
                 * token type.  Zero value causes "allow regexp" mode.
                 */
                comp_ctx->curr_token.t = 0;
                duk__advance(comp_ctx);
        }

        DUK_DDD(DUK_DDDPRINT("begin 1st pass"));
        duk__parse_stmts(comp_ctx,
                         1,             /* allow source elements */
                         expect_eof);   /* expect EOF instead of } */
        DUK_DDD(DUK_DDDPRINT("end 1st pass"));

        /*
         *  Second (and possibly third) pass.
         *
         *  Generate actual code.  In most cases the need for shuffle
         *  registers is detected during pass 1, but in some corner cases
         *  we'll only detect it during pass 2 and a third pass is then
         *  needed (see GH-115).
         */

        for (;;) {
                duk_bool_t needs_shuffle_before = comp_ctx->curr_func.needs_shuffle;
                compile_round++;

                /*
                 *  Rewind lexer.
                 *
                 *  duk__parse_stmts() expects curr_tok to be set; parse in "allow regexp
                 *  literal" mode with current strictness.
                 *
                 *  curr_token line number info should be initialized for pass 2 before
                 *  generating prologue, to ensure prologue bytecode gets nice line numbers.
                 */

                DUK_DDD(DUK_DDDPRINT("rewind lexer"));
                DUK_LEXER_SETPOINT(&comp_ctx->lex, &lex_pt);
                comp_ctx->curr_token.t = 0;  /* this is needed for regexp mode */
                comp_ctx->curr_token.start_line = 0;  /* needed for line number tracking (becomes prev_token.start_line) */
                duk__advance(comp_ctx);

                /*
                 *  Reset function state and perform register allocation, which creates
                 *  'varmap' for second pass.  Function prologue for variable declarations,
                 *  binding value initializations etc is emitted as a by-product.
                 *
                 *  Strict mode restrictions for duplicate and invalid argument
                 *  names are checked here now that we know whether the function
                 *  is actually strict.  See: test-dev-strict-mode-boundary.js.
                 *
                 *  Inner functions are compiled during pass 1 and are not reset.
                 */

                duk__reset_func_for_pass2(comp_ctx);
                func->in_directive_prologue = 1;
                func->in_scanning = 0;

                /* must be able to emit code, alloc consts, etc. */

                duk__init_varmap_and_prologue_for_pass2(comp_ctx,
                                                        (implicit_return_value ? &reg_stmt_value : NULL));
                func->reg_stmt_value = reg_stmt_value;

                temp_first = DUK__GETTEMP(comp_ctx);

                func->temp_first = temp_first;
                func->temp_next = temp_first;
                func->stmt_next = 0;
                func->label_next = 0;

                /* XXX: init or assert catch depth etc -- all values */
                func->id_access_arguments = 0;
                func->id_access_slow = 0;

                /*
                 *  Check function name validity now that we know strictness.
                 *  This only applies to function declarations and expressions,
                 *  not setter/getter name.
                 *
                 *  See: test-dev-strict-mode-boundary.js
                 */

                if (func->is_function && !func->is_setget && func->h_name != NULL) {
                        if (func->is_strict) {
                                if (duk__hstring_is_eval_or_arguments(comp_ctx, func->h_name)) {
                                        DUK_DDD(DUK_DDDPRINT("func name is 'eval' or 'arguments' in strict mode"));
                                        goto error_funcname;
                                }
                                if (DUK_HSTRING_HAS_STRICT_RESERVED_WORD(func->h_name)) {
                                        DUK_DDD(DUK_DDDPRINT("func name is a reserved word in strict mode"));
                                        goto error_funcname;
                                }
                        } else {
                                if (DUK_HSTRING_HAS_RESERVED_WORD(func->h_name) &&
                                    !DUK_HSTRING_HAS_STRICT_RESERVED_WORD(func->h_name)) {
                                        DUK_DDD(DUK_DDDPRINT("func name is a reserved word in non-strict mode"));
                                        goto error_funcname;
                                }
                        }
                }

                /*
                 *  Second pass parsing.
                 */

                if (implicit_return_value) {
                        /* Default implicit return value. */
                        duk__emit_extraop_bc(comp_ctx,
                                             DUK_EXTRAOP_LDUNDEF,
                                             0);
                }

                DUK_DDD(DUK_DDDPRINT("begin 2nd pass"));
                duk__parse_stmts(comp_ctx,
                                 1,             /* allow source elements */
                                 expect_eof);   /* expect EOF instead of } */
                DUK_DDD(DUK_DDDPRINT("end 2nd pass"));

                duk__update_lineinfo_currtoken(comp_ctx);

                if (needs_shuffle_before == comp_ctx->curr_func.needs_shuffle) {
                        /* Shuffle decision not changed. */
                        break;
                }
                if (compile_round >= 3) {
                        /* Should never happen but avoid infinite loop just in case. */
                        DUK_D(DUK_DPRINT("more than 3 compile passes needed, should never happen"));
                        DUK_ERROR_INTERNAL_DEFMSG(thr);
                }
                DUK_D(DUK_DPRINT("need additional round to compile function, round now %d", (int) compile_round));
        }

        /*
         *  Emit a final RETURN.
         *
         *  It would be nice to avoid emitting an unnecessary "return" opcode
         *  if the current PC is not reachable.  However, this cannot be reliably
         *  detected; even if the previous instruction is an unconditional jump,
         *  there may be a previous jump which jumps to current PC (which is the
         *  case for iteration and conditional statements, for instance).
         */

        /* XXX: request a "last statement is terminal" from duk__parse_stmt() and duk__parse_stmts();
         * we could avoid the last RETURN if we could ensure there is no way to get here
         * (directly or via a jump)
         */

        DUK_ASSERT(comp_ctx->curr_func.catch_depth == 0);
        if (reg_stmt_value >= 0) {
                duk__emit_a_b(comp_ctx,
                              DUK_OP_RETURN | DUK__EMIT_FLAG_NO_SHUFFLE_A,
                              (duk_regconst_t) DUK_BC_RETURN_FLAG_HAVE_RETVAL /*flags*/,
                              (duk_regconst_t) reg_stmt_value /*reg*/);
        } else {
                duk__emit_a_b(comp_ctx,
                              DUK_OP_RETURN | DUK__EMIT_FLAG_NO_SHUFFLE_A,
                              (duk_regconst_t) 0 /*flags*/,
                              (duk_regconst_t) 0 /*reg(ignored)*/);
        }

        /*
         *  Peephole optimize JUMP chains.
         */

        duk__peephole_optimize_bytecode(comp_ctx);

        /*
         *  comp_ctx->curr_func is now ready to be converted into an actual
         *  function template.
         */

        DUK__RECURSION_DECREASE(comp_ctx, thr);
        return;

 error_funcname:
        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_FUNC_NAME);
}

/*
 *  Parse a function-like expression:
 *
 *    - function expression
 *    - function declaration
 *    - function statement (non-standard)
 *    - setter/getter
 *
 *  Adds the function to comp_ctx->curr_func function table and returns the
 *  function number.
 *
 *  On entry, curr_token points to:
 *
 *    - the token after 'function' for function expression/declaration/statement
 *    - the token after 'set' or 'get' for setter/getter
 */

/* Parse formals. */
DUK_LOCAL void duk__parse_func_formals(duk_compiler_ctx *comp_ctx) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_bool_t first = 1;
        duk_uarridx_t n;

        for (;;) {
                if (comp_ctx->curr_token.t == DUK_TOK_RPAREN) {
                        break;
                }

                if (first) {
                        /* no comma */
                        first = 0;
                } else {
                        duk__advance_expect(comp_ctx, DUK_TOK_COMMA);
                }

                /* Note: when parsing a formal list in non-strict context, e.g.
                 * "implements" is parsed as an identifier.  When the function is
                 * later detected to be strict, the argument list must be rechecked
                 * against a larger set of reserved words (that of strict mode).
                 * This is handled by duk__parse_func_body().  Here we recognize
                 * whatever tokens are considered reserved in current strictness
                 * (which is not always enough).
                 */

                if (comp_ctx->curr_token.t != DUK_TOK_IDENTIFIER) {
                        DUK_ERROR_SYNTAX(thr, "expected identifier");
                }
                DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_IDENTIFIER);
                DUK_ASSERT(comp_ctx->curr_token.str1 != NULL);
                DUK_DDD(DUK_DDDPRINT("formal argument: %!O",
                                     (duk_heaphdr *) comp_ctx->curr_token.str1));

                /* XXX: append primitive */
                duk_push_hstring(ctx, comp_ctx->curr_token.str1);
                n = (duk_uarridx_t) duk_get_length(ctx, comp_ctx->curr_func.argnames_idx);
                duk_put_prop_index(ctx, comp_ctx->curr_func.argnames_idx, n);

                duk__advance(comp_ctx);  /* eat identifier */
        }
}

/* Parse a function-like expression, assuming that 'comp_ctx->curr_func' is
 * correctly set up.  Assumes that curr_token is just after 'function' (or
 * 'set'/'get' etc).
 */
DUK_LOCAL void duk__parse_func_like_raw(duk_compiler_ctx *comp_ctx, duk_bool_t is_decl, duk_bool_t is_setget) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;

        DUK_ASSERT(comp_ctx->curr_func.num_formals == 0);
        DUK_ASSERT(comp_ctx->curr_func.is_function == 1);
        DUK_ASSERT(comp_ctx->curr_func.is_eval == 0);
        DUK_ASSERT(comp_ctx->curr_func.is_global == 0);
        DUK_ASSERT(comp_ctx->curr_func.is_setget == is_setget);
        DUK_ASSERT(comp_ctx->curr_func.is_decl == is_decl);

        duk__update_lineinfo_currtoken(comp_ctx);

        /*
         *  Function name (if any)
         *
         *  We don't check for prohibited names here, because we don't
         *  yet know whether the function will be strict.  Function body
         *  parsing handles this retroactively.
         *
         *  For function expressions and declarations function name must
         *  be an Identifer (excludes reserved words).  For setter/getter
         *  it is a PropertyName which allows reserved words and also
         *  strings and numbers (e.g. "{ get 1() { ... } }").
         */

        if (is_setget) {
                /* PropertyName -> IdentifierName | StringLiteral | NumericLiteral */
                if (comp_ctx->curr_token.t_nores == DUK_TOK_IDENTIFIER ||
                    comp_ctx->curr_token.t == DUK_TOK_STRING) {
                        duk_push_hstring(ctx, comp_ctx->curr_token.str1);       /* keep in valstack */
                } else if (comp_ctx->curr_token.t == DUK_TOK_NUMBER) {
                        duk_push_number(ctx, comp_ctx->curr_token.num);
                        duk_to_string(ctx, -1);
                } else {
                        DUK_ERROR_SYNTAX(thr, DUK_STR_INVALID_GETSET_NAME);
                }
                comp_ctx->curr_func.h_name = duk_get_hstring(ctx, -1);  /* borrowed reference */
                DUK_ASSERT(comp_ctx->curr_func.h_name != NULL);
                duk__advance(comp_ctx);
        } else {
                /* Function name is an Identifier (not IdentifierName), but we get
                 * the raw name (not recognizing keywords) here and perform the name
                 * checks only after pass 1.
                 */
                if (comp_ctx->curr_token.t_nores == DUK_TOK_IDENTIFIER) {
                        duk_push_hstring(ctx, comp_ctx->curr_token.str1);       /* keep in valstack */
                        comp_ctx->curr_func.h_name = duk_get_hstring(ctx, -1);  /* borrowed reference */
                        DUK_ASSERT(comp_ctx->curr_func.h_name != NULL);
                        duk__advance(comp_ctx);
                } else {
                        /* valstack will be unbalanced, which is OK */
                        DUK_ASSERT(!is_setget);
                        if (is_decl) {
                                DUK_ERROR_SYNTAX(thr, DUK_STR_FUNC_NAME_REQUIRED);
                        }
                }
        }

        DUK_DDD(DUK_DDDPRINT("function name: %!O",
                             (duk_heaphdr *) comp_ctx->curr_func.h_name));

        /*
         *  Formal argument list
         *
         *  We don't check for prohibited names or for duplicate argument
         *  names here, becase we don't yet know whether the function will
         *  be strict.  Function body parsing handles this retroactively.
         */

        duk__advance_expect(comp_ctx, DUK_TOK_LPAREN);

        duk__parse_func_formals(comp_ctx);

        DUK_ASSERT(comp_ctx->curr_token.t == DUK_TOK_RPAREN);
        duk__advance(comp_ctx);

        /*
         *  Parse function body
         */

        duk__parse_func_body(comp_ctx,
                             0,   /* expect_eof */
                             0,   /* implicit_return_value */
                             DUK_TOK_LCURLY);  /* expect_token */

        /*
         *  Convert duk_compiler_func to a function template and add it
         *  to the parent function table.
         */

        duk__convert_to_func_template(comp_ctx, is_setget /*force_no_namebind*/);  /* -> [ ... func ] */
}

/* Parse an inner function, adding the function template to the current function's
 * function table.  Return a function number to be used by the outer function.
 *
 * Avoiding O(depth^2) inner function parsing is handled here.  On the first pass,
 * compile and register the function normally into the 'funcs' array, also recording
 * a lexer point (offset/line) to the closing brace of the function.  On the second
 * pass, skip the function and return the same 'fnum' as on the first pass by using
 * a running counter.
 *
 * An unfortunate side effect of this is that when parsing the inner function, almost
 * nothing is known of the outer function, i.e. the inner function's scope.  We don't
 * need that information at the moment, but it would allow some optimizations if it
 * were used.
 */
DUK_LOCAL duk_int_t duk__parse_func_like_fnum(duk_compiler_ctx *comp_ctx, duk_bool_t is_decl, duk_bool_t is_setget) {
        duk_hthread *thr = comp_ctx->thr;
        duk_context *ctx = (duk_context *) thr;
        duk_compiler_func old_func;
        duk_idx_t entry_top;
        duk_int_t fnum;

        /*
         *  On second pass, skip the function.
         */

        if (!comp_ctx->curr_func.in_scanning) {
                duk_lexer_point lex_pt;

                fnum = comp_ctx->curr_func.fnum_next++;
                duk_get_prop_index(ctx, comp_ctx->curr_func.funcs_idx, (duk_uarridx_t) (fnum * 3 + 1));
                lex_pt.offset = duk_to_int(ctx, -1);
                duk_pop(ctx);
                duk_get_prop_index(ctx, comp_ctx->curr_func.funcs_idx, (duk_uarridx_t) (fnum * 3 + 2));
                lex_pt.line = duk_to_int(ctx, -1);
                duk_pop(ctx);

                DUK_DDD(DUK_DDDPRINT("second pass of an inner func, skip the function, reparse closing brace; lex offset=%ld, line=%ld",
                                     (long) lex_pt.offset, (long) lex_pt.line));

                DUK_LEXER_SETPOINT(&comp_ctx->lex, &lex_pt);
                comp_ctx->curr_token.t = 0;  /* this is needed for regexp mode */
                comp_ctx->curr_token.start_line = 0;  /* needed for line number tracking (becomes prev_token.start_line) */
                duk__advance(comp_ctx);
                duk__advance_expect(comp_ctx, DUK_TOK_RCURLY);

                return fnum;
        }

        /*
         *  On first pass, perform actual parsing.  Remember valstack top on entry
         *  to restore it later, and switch to using a new function in comp_ctx.
         */

        entry_top = duk_get_top(ctx);
        DUK_DDD(DUK_DDDPRINT("before func: entry_top=%ld, curr_tok.start_offset=%ld",
                             (long) entry_top, (long) comp_ctx->curr_token.start_offset));

        DUK_MEMCPY(&old_func, &comp_ctx->curr_func, sizeof(duk_compiler_func));

        DUK_MEMZERO(&comp_ctx->curr_func, sizeof(duk_compiler_func));
        duk__init_func_valstack_slots(comp_ctx);
        DUK_ASSERT(comp_ctx->curr_func.num_formals == 0);

        /* inherit initial strictness from parent */
        comp_ctx->curr_func.is_strict = old_func.is_strict;

        DUK_ASSERT(comp_ctx->curr_func.is_notail == 0);
        comp_ctx->curr_func.is_function = 1;
        DUK_ASSERT(comp_ctx->curr_func.is_eval == 0);
        DUK_ASSERT(comp_ctx->curr_func.is_global == 0);
        comp_ctx->curr_func.is_setget = is_setget;
        comp_ctx->curr_func.is_decl = is_decl;

        /*
         *  Parse inner function
         */

        duk__parse_func_like_raw(comp_ctx, is_decl, is_setget);  /* pushes function template */

        /* prev_token.start_offset points to the closing brace here; when skipping
         * we're going to reparse the closing brace to ensure semicolon insertion
         * etc work as expected.
         */
        DUK_DDD(DUK_DDDPRINT("after func: prev_tok.start_offset=%ld, curr_tok.start_offset=%ld",
                             (long) comp_ctx->prev_token.start_offset, (long) comp_ctx->curr_token.start_offset));
        DUK_ASSERT(comp_ctx->lex.input[comp_ctx->prev_token.start_offset] == (duk_uint8_t) DUK_ASC_RCURLY);

        /* XXX: append primitive */
        DUK_ASSERT(duk_get_length(ctx, old_func.funcs_idx) == (duk_size_t) (old_func.fnum_next * 3));
        fnum = old_func.fnum_next++;

        if (fnum > DUK__MAX_FUNCS) {
                DUK_ERROR_RANGE(comp_ctx->thr, DUK_STR_FUNC_LIMIT);
        }

        /* array writes autoincrement length */
        (void) duk_put_prop_index(ctx, old_func.funcs_idx, (duk_uarridx_t) (fnum * 3));
        duk_push_size_t(ctx, comp_ctx->prev_token.start_offset);
        (void) duk_put_prop_index(ctx, old_func.funcs_idx, (duk_uarridx_t) (fnum * 3 + 1));
        duk_push_int(ctx, comp_ctx->prev_token.start_line);
        (void) duk_put_prop_index(ctx, old_func.funcs_idx, (duk_uarridx_t) (fnum * 3 + 2));

        /*
         *  Cleanup: restore original function, restore valstack state.
         */

        DUK_MEMCPY((void *) &comp_ctx->curr_func, (void *) &old_func, sizeof(duk_compiler_func));
        duk_set_top(ctx, entry_top);

        DUK_ASSERT_TOP(ctx, entry_top);

        return fnum;
}

/*
 *  Compile input string into an executable function template without
 *  arguments.
 *
 *  The string is parsed as the "Program" production of Ecmascript E5.
 *  Compilation context can be either global code or eval code (see E5
 *  Sections 14 and 15.1.2.1).
 *
 *  Input stack:  [ ... filename ]
 *  Output stack: [ ... func_template ]
 */

/* XXX: source code property */

DUK_LOCAL duk_ret_t duk__js_compile_raw(duk_context *ctx) {
        duk_hthread *thr = (duk_hthread *) ctx;
        duk_hstring *h_filename;
        duk__compiler_stkstate *comp_stk;
        duk_compiler_ctx *comp_ctx;
        duk_lexer_point *lex_pt;
        duk_compiler_func *func;
        duk_idx_t entry_top;
        duk_bool_t is_strict;
        duk_bool_t is_eval;
        duk_bool_t is_funcexpr;
        duk_small_uint_t flags;

        DUK_ASSERT(thr != NULL);

        /*
         *  Arguments check
         */

        entry_top = duk_get_top(ctx);
        DUK_ASSERT(entry_top >= 2);

        comp_stk = (duk__compiler_stkstate *) duk_require_pointer(ctx, -1);
        comp_ctx = &comp_stk->comp_ctx_alloc;
        lex_pt = &comp_stk->lex_pt_alloc;
        DUK_ASSERT(comp_ctx != NULL);
        DUK_ASSERT(lex_pt != NULL);

        flags = comp_stk->flags;
        is_eval = (flags & DUK_JS_COMPILE_FLAG_EVAL ? 1 : 0);
        is_strict = (flags & DUK_JS_COMPILE_FLAG_STRICT ? 1 : 0);
        is_funcexpr = (flags & DUK_JS_COMPILE_FLAG_FUNCEXPR ? 1 : 0);

        h_filename = duk_get_hstring(ctx, -2);  /* may be undefined */

        /*
         *  Init compiler and lexer contexts
         */

        func = &comp_ctx->curr_func;
#ifdef DUK_USE_EXPLICIT_NULL_INIT
        comp_ctx->thr = NULL;
        comp_ctx->h_filename = NULL;
        comp_ctx->prev_token.str1 = NULL;
        comp_ctx->prev_token.str2 = NULL;
        comp_ctx->curr_token.str1 = NULL;
        comp_ctx->curr_token.str2 = NULL;
#endif

        duk_require_stack(ctx, DUK__COMPILE_ENTRY_SLOTS);

        duk_push_dynamic_buffer(ctx, 0);       /* entry_top + 0 */
        duk_push_undefined(ctx);               /* entry_top + 1 */
        duk_push_undefined(ctx);               /* entry_top + 2 */
        duk_push_undefined(ctx);               /* entry_top + 3 */
        duk_push_undefined(ctx);               /* entry_top + 4 */

        comp_ctx->thr = thr;
        comp_ctx->h_filename = h_filename;
        comp_ctx->tok11_idx = entry_top + 1;
        comp_ctx->tok12_idx = entry_top + 2;
        comp_ctx->tok21_idx = entry_top + 3;
        comp_ctx->tok22_idx = entry_top + 4;
        comp_ctx->recursion_limit = DUK_USE_COMPILER_RECLIMIT;

        /* comp_ctx->lex has been pre-initialized by caller: it has been
         * zeroed and input/input_length has been set.
         */
        comp_ctx->lex.thr = thr;
        /* comp_ctx->lex.input and comp_ctx->lex.input_length filled by caller */
        comp_ctx->lex.slot1_idx = comp_ctx->tok11_idx;
        comp_ctx->lex.slot2_idx = comp_ctx->tok12_idx;
        comp_ctx->lex.buf_idx = entry_top + 0;
        comp_ctx->lex.buf = (duk_hbuffer_dynamic *) duk_get_hbuffer(ctx, entry_top + 0);
        DUK_ASSERT(comp_ctx->lex.buf != NULL);
        DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(comp_ctx->lex.buf) && !DUK_HBUFFER_HAS_EXTERNAL(comp_ctx->lex.buf));
        comp_ctx->lex.token_limit = DUK_COMPILER_TOKEN_LIMIT;

        lex_pt->offset = 0;
        lex_pt->line = 1;
        DUK_LEXER_SETPOINT(&comp_ctx->lex, lex_pt);    /* fills window */
        comp_ctx->curr_token.start_line = 0;  /* needed for line number tracking (becomes prev_token.start_line) */

        /*
         *  Initialize function state for a zero-argument function
         */

        duk__init_func_valstack_slots(comp_ctx);
        DUK_ASSERT(func->num_formals == 0);

        if (is_funcexpr) {
                /* Name will be filled from function expression, not by caller.
                 * This case is used by Function constructor and duk_compile()
                 * API with the DUK_COMPILE_FUNCTION option.
                 */
                DUK_ASSERT(func->h_name == NULL);
        } else {
                duk_push_hstring_stridx(ctx, (is_eval ? DUK_STRIDX_EVAL :
                                                        DUK_STRIDX_GLOBAL));
                func->h_name = duk_get_hstring(ctx, -1);
        }

        /*
         *  Parse a function body or a function-like expression, depending
         *  on flags.
         */

        func->is_strict = is_strict;
        func->is_setget = 0;
        func->is_decl = 0;

        if (is_funcexpr) {
                func->is_function = 1;
                func->is_eval = 0;
                func->is_global = 0;

                duk__advance(comp_ctx);  /* init 'curr_token' */
                duk__advance_expect(comp_ctx, DUK_TOK_FUNCTION);
                (void) duk__parse_func_like_raw(comp_ctx,
                                                0,      /* is_decl */
                                                0);     /* is_setget */
        } else {
                func->is_function = 0;
                func->is_eval = is_eval;
                func->is_global = !is_eval;

                duk__parse_func_body(comp_ctx,
                                     1,             /* expect_eof */
                                     1,             /* implicit_return_value */
                                     -1);           /* expect_token */
        }

        /*
         *  Convert duk_compiler_func to a function template
         */

        duk__convert_to_func_template(comp_ctx, 0 /*force_no_namebind*/);

        /*
         *  Wrapping duk_safe_call() will mangle the stack, just return stack top
         */

        /* [ ... filename (temps) func ] */

        return 1;
}

DUK_INTERNAL void duk_js_compile(duk_hthread *thr, const duk_uint8_t *src_buffer, duk_size_t src_length, duk_small_uint_t flags) {
        duk_context *ctx = (duk_context *) thr;
        duk__compiler_stkstate comp_stk;
        duk_compiler_ctx *prev_ctx;
        duk_ret_t safe_rc;

        /* XXX: this illustrates that a C catchpoint implemented using duk_safe_call()
         * is a bit heavy at the moment.  The wrapper compiles to ~180 bytes on x64.
         * Alternatives would be nice.
         */

        DUK_ASSERT(thr != NULL);
        DUK_ASSERT(src_buffer != NULL);

        /* preinitialize lexer state partially */
        DUK_MEMZERO(&comp_stk, sizeof(comp_stk));
        comp_stk.flags = flags;
        DUK_LEXER_INITCTX(&comp_stk.comp_ctx_alloc.lex);
        comp_stk.comp_ctx_alloc.lex.input = src_buffer;
        comp_stk.comp_ctx_alloc.lex.input_length = src_length;

        duk_push_pointer(ctx, (void *) &comp_stk);

        /* [ ... filename &comp_stk ] */

        prev_ctx = thr->compile_ctx;
        thr->compile_ctx = &comp_stk.comp_ctx_alloc;  /* for duk_error_augment.c */
        safe_rc = duk_safe_call(ctx, duk__js_compile_raw, 2 /*nargs*/, 1 /*nret*/);
        thr->compile_ctx = prev_ctx;  /* must restore reliably before returning */

        if (safe_rc != DUK_EXEC_SUCCESS) {
                duk_throw(ctx);
        }

        /* [ ... template ] */
}