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7c673cae FG |
1 | /* |
2 | * Identifier access and function closure handling. | |
3 | * | |
4 | * Provides the primitives for slow path identifier accesses: GETVAR, | |
5 | * PUTVAR, DELVAR, etc. The fast path, direct register accesses, should | |
6 | * be used for most identifier accesses. Consequently, these slow path | |
7 | * primitives should be optimized for maximum compactness. | |
8 | * | |
9 | * Ecmascript environment records (declarative and object) are represented | |
10 | * as internal objects with control keys. Environment records have a | |
11 | * parent record ("outer environment reference") which is represented by | |
12 | * the implicit prototype for technical reasons (in other words, it is a | |
13 | * convenient field). The prototype chain is not followed in the ordinary | |
14 | * sense for variable lookups. | |
15 | * | |
16 | * See identifier-handling.rst for more details on the identifier algorithms | |
17 | * and the internal representation. See function-objects.rst for details on | |
18 | * what function templates and instances are expected to look like. | |
19 | * | |
20 | * Care must be taken to avoid duk_tval pointer invalidation caused by | |
21 | * e.g. value stack or object resizing. | |
22 | * | |
23 | * TODO: properties for function instances could be initialized much more | |
24 | * efficiently by creating a property allocation for a certain size and | |
25 | * filling in keys and values directly (and INCREFing both with "bulk incref" | |
26 | * primitives. | |
27 | * | |
28 | * XXX: duk_hobject_getprop() and duk_hobject_putprop() calls are a bit | |
29 | * awkward (especially because they follow the prototype chain); rework | |
30 | * if "raw" own property helpers are added. | |
31 | */ | |
32 | ||
33 | #include "duk_internal.h" | |
34 | ||
35 | /* | |
36 | * Local result type for duk__get_identifier_reference() lookup. | |
37 | */ | |
38 | ||
39 | typedef struct { | |
40 | duk_hobject *holder; /* for object-bound identifiers */ | |
41 | duk_tval *value; /* for register-bound and declarative env identifiers */ | |
42 | duk_int_t attrs; /* property attributes for identifier (relevant if value != NULL) */ | |
43 | duk_tval *this_binding; | |
44 | duk_hobject *env; | |
45 | } duk__id_lookup_result; | |
46 | ||
47 | /* | |
48 | * Create a new function object based on a "template function" which contains | |
49 | * compiled bytecode, constants, etc, but lacks a lexical environment. | |
50 | * | |
51 | * Ecmascript requires that each created closure is a separate object, with | |
52 | * its own set of editable properties. However, structured property values | |
53 | * (such as the formal arguments list and the variable map) are shared. | |
54 | * Also the bytecode, constants, and inner functions are shared. | |
55 | * | |
56 | * See E5 Section 13.2 for detailed requirements on the function objects; | |
57 | * there are no similar requirements for function "templates" which are an | |
58 | * implementation dependent internal feature. Also see function-objects.rst | |
59 | * for a discussion on the function instance properties provided by this | |
60 | * implementation. | |
61 | * | |
62 | * Notes: | |
63 | * | |
64 | * * Order of internal properties should match frequency of use, since the | |
65 | * properties will be linearly scanned on lookup (functions usually don't | |
66 | * have enough properties to warrant a hash part). | |
67 | * | |
68 | * * The created closure is independent of its template; they do share the | |
69 | * same 'data' buffer object, but the template object itself can be freed | |
70 | * even if the closure object remains reachable. | |
71 | */ | |
72 | ||
73 | DUK_LOCAL void duk__inc_data_inner_refcounts(duk_hthread *thr, duk_hcompiledfunction *f) { | |
74 | duk_tval *tv, *tv_end; | |
75 | duk_hobject **funcs, **funcs_end; | |
76 | ||
11fdf7f2 TL |
77 | /* If function creation fails due to out-of-memory, the data buffer |
78 | * pointer may be NULL in some cases. That's actually possible for | |
79 | * GC code, but shouldn't be possible here because the incomplete | |
80 | * function will be unwound from the value stack and never instantiated. | |
81 | */ | |
82 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, f) != NULL); | |
7c673cae FG |
83 | DUK_UNREF(thr); |
84 | ||
85 | tv = DUK_HCOMPILEDFUNCTION_GET_CONSTS_BASE(thr->heap, f); | |
86 | tv_end = DUK_HCOMPILEDFUNCTION_GET_CONSTS_END(thr->heap, f); | |
87 | while (tv < tv_end) { | |
88 | DUK_TVAL_INCREF(thr, tv); | |
89 | tv++; | |
90 | } | |
91 | ||
92 | funcs = DUK_HCOMPILEDFUNCTION_GET_FUNCS_BASE(thr->heap, f); | |
93 | funcs_end = DUK_HCOMPILEDFUNCTION_GET_FUNCS_END(thr->heap, f); | |
94 | while (funcs < funcs_end) { | |
95 | DUK_HEAPHDR_INCREF(thr, (duk_heaphdr *) *funcs); | |
96 | funcs++; | |
97 | } | |
98 | } | |
99 | ||
100 | /* Push a new closure on the stack. | |
101 | * | |
102 | * Note: if fun_temp has NEWENV, i.e. a new lexical and variable declaration | |
103 | * is created when the function is called, only outer_lex_env matters | |
104 | * (outer_var_env is ignored and may or may not be same as outer_lex_env). | |
105 | */ | |
106 | ||
107 | DUK_LOCAL const duk_uint16_t duk__closure_copy_proplist[] = { | |
108 | /* order: most frequent to least frequent */ | |
109 | DUK_STRIDX_INT_VARMAP, | |
110 | DUK_STRIDX_INT_FORMALS, | |
111 | DUK_STRIDX_NAME, | |
112 | DUK_STRIDX_INT_PC2LINE, | |
113 | DUK_STRIDX_FILE_NAME, | |
114 | DUK_STRIDX_INT_SOURCE | |
115 | }; | |
116 | ||
117 | DUK_INTERNAL | |
118 | void duk_js_push_closure(duk_hthread *thr, | |
119 | duk_hcompiledfunction *fun_temp, | |
120 | duk_hobject *outer_var_env, | |
11fdf7f2 TL |
121 | duk_hobject *outer_lex_env, |
122 | duk_bool_t add_auto_proto) { | |
7c673cae FG |
123 | duk_context *ctx = (duk_context *) thr; |
124 | duk_hcompiledfunction *fun_clos; | |
125 | duk_small_uint_t i; | |
126 | duk_uint_t len_value; | |
127 | ||
128 | DUK_ASSERT(fun_temp != NULL); | |
129 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, fun_temp) != NULL); | |
130 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_FUNCS(thr->heap, fun_temp) != NULL); | |
131 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_BYTECODE(thr->heap, fun_temp) != NULL); | |
132 | DUK_ASSERT(outer_var_env != NULL); | |
133 | DUK_ASSERT(outer_lex_env != NULL); | |
11fdf7f2 | 134 | DUK_UNREF(len_value); |
7c673cae FG |
135 | |
136 | duk_push_compiledfunction(ctx); | |
137 | duk_push_hobject(ctx, &fun_temp->obj); /* -> [ ... closure template ] */ | |
138 | ||
139 | fun_clos = (duk_hcompiledfunction *) duk_get_hcompiledfunction(ctx, -2); | |
140 | DUK_ASSERT(fun_clos != NULL); | |
141 | DUK_ASSERT(DUK_HOBJECT_IS_COMPILEDFUNCTION((duk_hobject *) fun_clos)); | |
142 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, fun_clos) == NULL); | |
143 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_FUNCS(thr->heap, fun_clos) == NULL); | |
144 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_BYTECODE(thr->heap, fun_clos) == NULL); | |
145 | ||
146 | DUK_HCOMPILEDFUNCTION_SET_DATA(thr->heap, fun_clos, DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, fun_temp)); | |
147 | DUK_HCOMPILEDFUNCTION_SET_FUNCS(thr->heap, fun_clos, DUK_HCOMPILEDFUNCTION_GET_FUNCS(thr->heap, fun_temp)); | |
148 | DUK_HCOMPILEDFUNCTION_SET_BYTECODE(thr->heap, fun_clos, DUK_HCOMPILEDFUNCTION_GET_BYTECODE(thr->heap, fun_temp)); | |
149 | ||
150 | /* Note: all references inside 'data' need to get their refcounts | |
151 | * upped too. This is the case because refcounts are decreased | |
152 | * through every function referencing 'data' independently. | |
153 | */ | |
154 | ||
155 | DUK_HBUFFER_INCREF(thr, DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, fun_clos)); | |
156 | duk__inc_data_inner_refcounts(thr, fun_temp); | |
157 | ||
158 | fun_clos->nregs = fun_temp->nregs; | |
159 | fun_clos->nargs = fun_temp->nargs; | |
160 | #if defined(DUK_USE_DEBUGGER_SUPPORT) | |
161 | fun_clos->start_line = fun_temp->start_line; | |
162 | fun_clos->end_line = fun_temp->end_line; | |
163 | #endif | |
164 | ||
165 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, fun_clos) != NULL); | |
166 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_FUNCS(thr->heap, fun_clos) != NULL); | |
167 | DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_BYTECODE(thr->heap, fun_clos) != NULL); | |
168 | ||
169 | /* XXX: could also copy from template, but there's no way to have any | |
170 | * other value here now (used code has no access to the template). | |
171 | */ | |
172 | DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, &fun_clos->obj, thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]); | |
173 | ||
174 | /* | |
175 | * Init/assert flags, copying them where appropriate. Some flags | |
176 | * (like NEWENV) are processed separately below. | |
177 | */ | |
178 | ||
179 | /* XXX: copy flags using a mask */ | |
180 | ||
181 | DUK_ASSERT(DUK_HOBJECT_HAS_EXTENSIBLE(&fun_clos->obj)); | |
182 | DUK_HOBJECT_SET_CONSTRUCTABLE(&fun_clos->obj); /* Note: not set in template (has no "prototype") */ | |
183 | DUK_ASSERT(DUK_HOBJECT_HAS_CONSTRUCTABLE(&fun_clos->obj)); | |
184 | DUK_ASSERT(!DUK_HOBJECT_HAS_BOUND(&fun_clos->obj)); | |
185 | DUK_ASSERT(DUK_HOBJECT_HAS_COMPILEDFUNCTION(&fun_clos->obj)); | |
186 | DUK_ASSERT(!DUK_HOBJECT_HAS_NATIVEFUNCTION(&fun_clos->obj)); | |
187 | DUK_ASSERT(!DUK_HOBJECT_HAS_THREAD(&fun_clos->obj)); | |
188 | /* DUK_HOBJECT_FLAG_ARRAY_PART: don't care */ | |
189 | if (DUK_HOBJECT_HAS_STRICT(&fun_temp->obj)) { | |
190 | DUK_HOBJECT_SET_STRICT(&fun_clos->obj); | |
191 | } | |
192 | if (DUK_HOBJECT_HAS_NOTAIL(&fun_temp->obj)) { | |
193 | DUK_HOBJECT_SET_NOTAIL(&fun_clos->obj); | |
194 | } | |
195 | /* DUK_HOBJECT_FLAG_NEWENV: handled below */ | |
196 | if (DUK_HOBJECT_HAS_NAMEBINDING(&fun_temp->obj)) { | |
197 | /* Although NAMEBINDING is not directly needed for using | |
198 | * function instances, it's needed by bytecode dump/load | |
199 | * so copy it too. | |
200 | */ | |
201 | DUK_HOBJECT_SET_NAMEBINDING(&fun_clos->obj); | |
202 | } | |
203 | if (DUK_HOBJECT_HAS_CREATEARGS(&fun_temp->obj)) { | |
204 | DUK_HOBJECT_SET_CREATEARGS(&fun_clos->obj); | |
205 | } | |
206 | DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARRAY(&fun_clos->obj)); | |
207 | DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(&fun_clos->obj)); | |
208 | DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(&fun_clos->obj)); | |
209 | ||
210 | /* | |
211 | * Setup environment record properties based on the template and | |
212 | * its flags. | |
213 | * | |
214 | * If DUK_HOBJECT_HAS_NEWENV(fun_temp) is true, the environment | |
215 | * records represent identifiers "outside" the function; the | |
216 | * "inner" environment records are created on demand. Otherwise, | |
217 | * the environment records are those that will be directly used | |
218 | * (e.g. for declarations). | |
219 | * | |
220 | * _Lexenv is always set; _Varenv defaults to _Lexenv if missing, | |
221 | * so _Varenv is only set if _Lexenv != _Varenv. | |
222 | * | |
223 | * This is relatively complex, see doc/identifier-handling.rst. | |
224 | */ | |
225 | ||
226 | if (DUK_HOBJECT_HAS_NEWENV(&fun_temp->obj)) { | |
227 | DUK_HOBJECT_SET_NEWENV(&fun_clos->obj); | |
228 | ||
229 | if (DUK_HOBJECT_HAS_NAMEBINDING(&fun_temp->obj)) { | |
230 | duk_hobject *proto; | |
231 | ||
232 | /* | |
233 | * Named function expression, name needs to be bound | |
234 | * in an intermediate environment record. The "outer" | |
235 | * lexical/variable environment will thus be: | |
236 | * | |
237 | * a) { funcname: <func>, __prototype: outer_lex_env } | |
238 | * b) { funcname: <func>, __prototype: <globalenv> } (if outer_lex_env missing) | |
239 | */ | |
240 | ||
241 | DUK_ASSERT(duk_has_prop_stridx(ctx, -1, DUK_STRIDX_NAME)); /* required if NAMEBINDING set */ | |
242 | ||
243 | if (outer_lex_env) { | |
244 | proto = outer_lex_env; | |
245 | } else { | |
246 | proto = thr->builtins[DUK_BIDX_GLOBAL_ENV]; | |
247 | } | |
248 | ||
249 | /* -> [ ... closure template env ] */ | |
250 | (void) duk_push_object_helper_proto(ctx, | |
251 | DUK_HOBJECT_FLAG_EXTENSIBLE | | |
252 | DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DECENV), | |
253 | proto); | |
254 | ||
255 | /* It's important that duk_xdef_prop() is a 'raw define' so that any | |
256 | * properties in an ancestor are never an issue (they should never be | |
257 | * e.g. non-writable, but just in case). | |
258 | */ | |
259 | duk_get_prop_stridx(ctx, -2, DUK_STRIDX_NAME); /* -> [ ... closure template env funcname ] */ | |
260 | duk_dup(ctx, -4); /* -> [ ... closure template env funcname closure ] */ | |
261 | duk_xdef_prop(ctx, -3, DUK_PROPDESC_FLAGS_NONE); /* -> [ ... closure template env ] */ | |
262 | /* env[funcname] = closure */ | |
263 | ||
264 | /* [ ... closure template env ] */ | |
265 | ||
266 | duk_xdef_prop_stridx(ctx, -3, DUK_STRIDX_INT_LEXENV, DUK_PROPDESC_FLAGS_WC); | |
267 | /* since closure has NEWENV, never define DUK_STRIDX_INT_VARENV, as it | |
268 | * will be ignored anyway | |
269 | */ | |
270 | ||
271 | /* [ ... closure template ] */ | |
272 | } else { | |
273 | /* | |
274 | * Other cases (function declaration, anonymous function expression, | |
275 | * strict direct eval code). The "outer" environment will be whatever | |
276 | * the caller gave us. | |
277 | */ | |
278 | ||
279 | duk_push_hobject(ctx, outer_lex_env); /* -> [ ... closure template env ] */ | |
280 | duk_xdef_prop_stridx(ctx, -3, DUK_STRIDX_INT_LEXENV, DUK_PROPDESC_FLAGS_WC); | |
281 | /* since closure has NEWENV, never define DUK_STRIDX_INT_VARENV, as it | |
282 | * will be ignored anyway | |
283 | */ | |
284 | ||
285 | /* [ ... closure template ] */ | |
286 | } | |
287 | } else { | |
288 | /* | |
289 | * Function gets no new environment when called. This is the | |
290 | * case for global code, indirect eval code, and non-strict | |
291 | * direct eval code. There is no direct correspondence to the | |
292 | * E5 specification, as global/eval code is not exposed as a | |
293 | * function. | |
294 | */ | |
295 | ||
296 | DUK_ASSERT(!DUK_HOBJECT_HAS_NAMEBINDING(&fun_temp->obj)); | |
297 | ||
298 | duk_push_hobject(ctx, outer_lex_env); /* -> [ ... closure template env ] */ | |
299 | duk_xdef_prop_stridx(ctx, -3, DUK_STRIDX_INT_LEXENV, DUK_PROPDESC_FLAGS_WC); | |
300 | ||
301 | if (outer_var_env != outer_lex_env) { | |
302 | duk_push_hobject(ctx, outer_var_env); /* -> [ ... closure template env ] */ | |
303 | duk_xdef_prop_stridx(ctx, -3, DUK_STRIDX_INT_VARENV, DUK_PROPDESC_FLAGS_WC); | |
304 | } | |
305 | } | |
306 | #ifdef DUK_USE_DDDPRINT | |
307 | duk_get_prop_stridx(ctx, -2, DUK_STRIDX_INT_VARENV); | |
308 | duk_get_prop_stridx(ctx, -3, DUK_STRIDX_INT_LEXENV); | |
309 | DUK_DDD(DUK_DDDPRINT("closure varenv -> %!ipT, lexenv -> %!ipT", | |
310 | (duk_tval *) duk_get_tval(ctx, -2), | |
311 | (duk_tval *) duk_get_tval(ctx, -1))); | |
312 | duk_pop_2(ctx); | |
313 | #endif | |
314 | ||
315 | /* | |
316 | * Copy some internal properties directly | |
317 | * | |
318 | * The properties will be writable and configurable, but not enumerable. | |
319 | */ | |
320 | ||
321 | /* [ ... closure template ] */ | |
322 | ||
323 | DUK_DDD(DUK_DDDPRINT("copying properties: closure=%!iT, template=%!iT", | |
324 | (duk_tval *) duk_get_tval(ctx, -2), | |
325 | (duk_tval *) duk_get_tval(ctx, -1))); | |
326 | ||
327 | for (i = 0; i < (duk_small_uint_t) (sizeof(duk__closure_copy_proplist) / sizeof(duk_uint16_t)); i++) { | |
328 | duk_small_int_t stridx = (duk_small_int_t) duk__closure_copy_proplist[i]; | |
329 | if (duk_get_prop_stridx(ctx, -1, stridx)) { | |
330 | /* [ ... closure template val ] */ | |
331 | DUK_DDD(DUK_DDDPRINT("copying property, stridx=%ld -> found", (long) stridx)); | |
332 | duk_xdef_prop_stridx(ctx, -3, stridx, DUK_PROPDESC_FLAGS_WC); | |
333 | } else { | |
334 | DUK_DDD(DUK_DDDPRINT("copying property, stridx=%ld -> not found", (long) stridx)); | |
335 | duk_pop(ctx); | |
336 | } | |
337 | } | |
338 | ||
339 | /* | |
340 | * "length" maps to number of formals (E5 Section 13.2) for function | |
341 | * declarations/expressions (non-bound functions). Note that 'nargs' | |
342 | * is NOT necessarily equal to the number of arguments. | |
343 | */ | |
344 | ||
345 | /* [ ... closure template ] */ | |
346 | ||
347 | len_value = 0; | |
348 | ||
349 | /* XXX: use helper for size optimization */ | |
350 | if (duk_get_prop_stridx(ctx, -2, DUK_STRIDX_INT_FORMALS)) { | |
351 | /* [ ... closure template formals ] */ | |
352 | DUK_ASSERT(duk_has_prop_stridx(ctx, -1, DUK_STRIDX_LENGTH)); | |
353 | DUK_ASSERT(duk_get_length(ctx, -1) <= DUK_UINT_MAX); /* formal arg limits */ | |
354 | len_value = (duk_uint_t) duk_get_length(ctx, -1); | |
355 | } else { | |
356 | /* XXX: what to do if _Formals is not empty but compiler has | |
357 | * optimized it away -- read length from an explicit property | |
358 | * then? | |
359 | */ | |
360 | } | |
361 | duk_pop(ctx); | |
362 | ||
363 | duk_push_uint(ctx, len_value); /* [ ... closure template len_value ] */ | |
364 | duk_xdef_prop_stridx(ctx, -3, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_NONE); | |
365 | ||
366 | /* | |
367 | * "prototype" is, by default, a fresh object with the "constructor" | |
368 | * property. | |
369 | * | |
370 | * Note that this creates a circular reference for every function | |
371 | * instance (closure) which prevents refcount-based collection of | |
372 | * function instances. | |
373 | * | |
374 | * XXX: Try to avoid creating the default prototype object, because | |
375 | * many functions are not used as constructors and the default | |
376 | * prototype is unnecessary. Perhaps it could be created on-demand | |
377 | * when it is first accessed? | |
378 | */ | |
379 | ||
380 | /* [ ... closure template ] */ | |
381 | ||
11fdf7f2 TL |
382 | if (add_auto_proto) { |
383 | duk_push_object(ctx); /* -> [ ... closure template newobj ] */ | |
384 | duk_dup(ctx, -3); /* -> [ ... closure template newobj closure ] */ | |
385 | duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_CONSTRUCTOR, DUK_PROPDESC_FLAGS_WC); /* -> [ ... closure template newobj ] */ | |
386 | duk_compact(ctx, -1); /* compact the prototype */ | |
387 | duk_xdef_prop_stridx(ctx, -3, DUK_STRIDX_PROTOTYPE, DUK_PROPDESC_FLAGS_W); /* -> [ ... closure template ] */ | |
388 | } | |
7c673cae FG |
389 | |
390 | /* | |
391 | * "arguments" and "caller" must be mapped to throwers for strict | |
392 | * mode and bound functions (E5 Section 15.3.5). | |
393 | * | |
394 | * XXX: This is expensive to have for every strict function instance. | |
395 | * Try to implement as virtual properties or on-demand created properties. | |
396 | */ | |
397 | ||
398 | /* [ ... closure template ] */ | |
399 | ||
400 | if (DUK_HOBJECT_HAS_STRICT(&fun_clos->obj)) { | |
401 | duk_xdef_prop_stridx_thrower(ctx, -2, DUK_STRIDX_CALLER, DUK_PROPDESC_FLAGS_NONE); | |
402 | duk_xdef_prop_stridx_thrower(ctx, -2, DUK_STRIDX_LC_ARGUMENTS, DUK_PROPDESC_FLAGS_NONE); | |
403 | } else { | |
404 | #ifdef DUK_USE_NONSTD_FUNC_CALLER_PROPERTY | |
405 | DUK_DDD(DUK_DDDPRINT("function is non-strict and non-standard 'caller' property in use, add initial 'null' value")); | |
406 | duk_push_null(ctx); | |
407 | duk_xdef_prop_stridx(ctx, -3, DUK_STRIDX_CALLER, DUK_PROPDESC_FLAGS_NONE); | |
408 | #else | |
409 | DUK_DDD(DUK_DDDPRINT("function is non-strict and non-standard 'caller' property not used")); | |
410 | #endif | |
411 | } | |
412 | ||
413 | /* | |
414 | * "name" is a non-standard property found in at least V8, Rhino, smjs. | |
415 | * For Rhino and smjs it is non-writable, non-enumerable, and non-configurable; | |
416 | * for V8 it is writable, non-enumerable, non-configurable. It is also defined | |
417 | * for an anonymous function expression in which case the value is an empty string. | |
418 | * We could also leave name 'undefined' for anonymous functions but that would | |
419 | * differ from behavior of other engines, so use an empty string. | |
420 | * | |
421 | * XXX: make optional? costs something per function. | |
422 | */ | |
423 | ||
424 | /* [ ... closure template ] */ | |
425 | ||
426 | if (duk_get_prop_stridx(ctx, -1, DUK_STRIDX_NAME)) { | |
427 | /* [ ... closure template name ] */ | |
428 | DUK_ASSERT(duk_is_string(ctx, -1)); | |
429 | } else { | |
430 | /* [ ... closure template undefined ] */ | |
431 | duk_pop(ctx); | |
432 | duk_push_hstring_stridx(ctx, DUK_STRIDX_EMPTY_STRING); | |
433 | } | |
434 | duk_xdef_prop_stridx(ctx, -3, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_NONE); /* -> [ ... closure template ] */ | |
435 | ||
436 | /* | |
437 | * Compact the closure, in most cases no properties will be added later. | |
438 | * Also, without this the closures end up having unused property slots | |
439 | * (e.g. in Duktape 0.9.0, 8 slots would be allocated and only 7 used). | |
440 | * A better future solution would be to allocate the closure directly | |
441 | * to correct size (and setup the properties directly without going | |
442 | * through the API). | |
443 | */ | |
444 | ||
445 | duk_compact(ctx, -2); | |
446 | ||
447 | /* | |
448 | * Some assertions (E5 Section 13.2). | |
449 | */ | |
450 | ||
451 | DUK_ASSERT(DUK_HOBJECT_GET_CLASS_NUMBER(&fun_clos->obj) == DUK_HOBJECT_CLASS_FUNCTION); | |
452 | DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, &fun_clos->obj) == thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]); | |
453 | DUK_ASSERT(DUK_HOBJECT_HAS_EXTENSIBLE(&fun_clos->obj)); | |
454 | DUK_ASSERT(duk_has_prop_stridx(ctx, -2, DUK_STRIDX_LENGTH) != 0); | |
11fdf7f2 | 455 | DUK_ASSERT(add_auto_proto == 0 || duk_has_prop_stridx(ctx, -2, DUK_STRIDX_PROTOTYPE) != 0); |
7c673cae FG |
456 | DUK_ASSERT(duk_has_prop_stridx(ctx, -2, DUK_STRIDX_NAME) != 0); /* non-standard */ |
457 | DUK_ASSERT(!DUK_HOBJECT_HAS_STRICT(&fun_clos->obj) || | |
458 | duk_has_prop_stridx(ctx, -2, DUK_STRIDX_CALLER) != 0); | |
459 | DUK_ASSERT(!DUK_HOBJECT_HAS_STRICT(&fun_clos->obj) || | |
460 | duk_has_prop_stridx(ctx, -2, DUK_STRIDX_LC_ARGUMENTS) != 0); | |
461 | ||
462 | /* | |
463 | * Finish | |
464 | */ | |
465 | ||
466 | /* [ ... closure template ] */ | |
467 | ||
468 | DUK_DDD(DUK_DDDPRINT("created function instance: template=%!iT -> closure=%!iT", | |
469 | (duk_tval *) duk_get_tval(ctx, -1), | |
470 | (duk_tval *) duk_get_tval(ctx, -2))); | |
471 | ||
472 | duk_pop(ctx); | |
473 | ||
474 | /* [ ... closure ] */ | |
475 | } | |
476 | ||
477 | /* | |
478 | * Delayed activation environment record initialization (for functions | |
479 | * with NEWENV). | |
480 | * | |
481 | * The non-delayed initialization is handled by duk_handle_call(). | |
482 | */ | |
483 | ||
484 | /* shared helper */ | |
485 | DUK_INTERNAL | |
486 | duk_hobject *duk_create_activation_environment_record(duk_hthread *thr, | |
487 | duk_hobject *func, | |
488 | duk_size_t idx_bottom) { | |
489 | duk_context *ctx = (duk_context *) thr; | |
490 | duk_hobject *env; | |
491 | duk_hobject *parent; | |
492 | duk_tval *tv; | |
493 | ||
494 | DUK_ASSERT(thr != NULL); | |
495 | DUK_ASSERT(func != NULL); | |
496 | ||
497 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, func, DUK_HTHREAD_STRING_INT_LEXENV(thr)); | |
498 | if (tv) { | |
499 | DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv)); | |
500 | DUK_ASSERT(DUK_HOBJECT_IS_ENV(DUK_TVAL_GET_OBJECT(tv))); | |
501 | parent = DUK_TVAL_GET_OBJECT(tv); | |
502 | } else { | |
503 | parent = thr->builtins[DUK_BIDX_GLOBAL_ENV]; | |
504 | } | |
505 | ||
506 | (void) duk_push_object_helper(ctx, | |
507 | DUK_HOBJECT_FLAG_EXTENSIBLE | | |
508 | DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DECENV), | |
509 | -1); /* no prototype, updated below */ | |
510 | env = duk_require_hobject(ctx, -1); | |
511 | DUK_ASSERT(env != NULL); | |
512 | DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, env, parent); /* parent env is the prototype */ | |
513 | ||
514 | /* open scope information, for compiled functions only */ | |
515 | ||
516 | if (DUK_HOBJECT_IS_COMPILEDFUNCTION(func)) { | |
517 | duk_push_hthread(ctx, thr); | |
518 | duk_xdef_prop_stridx_wec(ctx, -2, DUK_STRIDX_INT_THREAD); | |
519 | duk_push_hobject(ctx, func); | |
520 | duk_xdef_prop_stridx_wec(ctx, -2, DUK_STRIDX_INT_CALLEE); | |
521 | duk_push_size_t(ctx, idx_bottom); | |
522 | duk_xdef_prop_stridx_wec(ctx, -2, DUK_STRIDX_INT_REGBASE); | |
523 | } | |
524 | ||
525 | return env; | |
526 | } | |
527 | ||
528 | DUK_INTERNAL | |
529 | void duk_js_init_activation_environment_records_delayed(duk_hthread *thr, | |
530 | duk_activation *act) { | |
531 | duk_context *ctx = (duk_context *) thr; | |
532 | duk_hobject *func; | |
533 | duk_hobject *env; | |
11fdf7f2 | 534 | duk_size_t act_off; |
7c673cae | 535 | |
11fdf7f2 TL |
536 | DUK_ASSERT(act != NULL); |
537 | act_off = (duk_size_t) ((duk_uint8_t *) act - (duk_uint8_t *) thr->callstack); | |
7c673cae FG |
538 | func = DUK_ACT_GET_FUNC(act); |
539 | DUK_ASSERT(func != NULL); | |
540 | DUK_ASSERT(!DUK_HOBJECT_HAS_BOUND(func)); /* bound functions are never in act 'func' */ | |
541 | ||
542 | /* | |
543 | * Delayed initialization only occurs for 'NEWENV' functions. | |
544 | */ | |
545 | ||
546 | DUK_ASSERT(DUK_HOBJECT_HAS_NEWENV(func)); | |
547 | DUK_ASSERT(act->lex_env == NULL); | |
548 | DUK_ASSERT(act->var_env == NULL); | |
549 | ||
550 | env = duk_create_activation_environment_record(thr, func, act->idx_bottom); | |
551 | DUK_ASSERT(env != NULL); | |
11fdf7f2 | 552 | act = (duk_activation *) ((duk_uint8_t *) thr->callstack + act_off); |
7c673cae FG |
553 | |
554 | DUK_DDD(DUK_DDDPRINT("created delayed fresh env: %!ipO", (duk_heaphdr *) env)); | |
555 | #ifdef DUK_USE_DDDPRINT | |
556 | { | |
557 | duk_hobject *p = env; | |
558 | while (p) { | |
559 | DUK_DDD(DUK_DDDPRINT(" -> %!ipO", (duk_heaphdr *) p)); | |
560 | p = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, p); | |
561 | } | |
562 | } | |
563 | #endif | |
564 | ||
565 | act->lex_env = env; | |
566 | act->var_env = env; | |
567 | DUK_HOBJECT_INCREF(thr, env); /* XXX: incref by count (here 2 times) */ | |
568 | DUK_HOBJECT_INCREF(thr, env); | |
569 | ||
570 | duk_pop(ctx); | |
571 | } | |
572 | ||
573 | /* | |
574 | * Closing environment records. | |
575 | * | |
576 | * The environment record MUST be closed with the thread where its activation | |
577 | * is. In other words (if 'env' is open): | |
578 | * | |
579 | * - 'thr' must match _env.thread | |
580 | * - 'func' must match _env.callee | |
581 | * - 'regbase' must match _env.regbase | |
582 | * | |
583 | * These are not looked up from the env to minimize code size. | |
584 | * | |
585 | * XXX: should access the own properties directly instead of using the API | |
586 | */ | |
587 | ||
588 | DUK_INTERNAL void duk_js_close_environment_record(duk_hthread *thr, duk_hobject *env, duk_hobject *func, duk_size_t regbase) { | |
589 | duk_context *ctx = (duk_context *) thr; | |
590 | duk_uint_fast32_t i; | |
591 | ||
592 | DUK_ASSERT(thr != NULL); | |
593 | DUK_ASSERT(env != NULL); | |
594 | /* func is NULL for lightfuncs */ | |
595 | ||
596 | if (!DUK_HOBJECT_IS_DECENV(env) || DUK_HOBJECT_HAS_ENVRECCLOSED(env)) { | |
597 | DUK_DDD(DUK_DDDPRINT("environment record not a declarative record, " | |
598 | "or already closed: %!iO", | |
599 | (duk_heaphdr *) env)); | |
600 | return; | |
601 | } | |
602 | ||
603 | DUK_DDD(DUK_DDDPRINT("closing environment record: %!iO, func: %!iO, regbase: %ld", | |
604 | (duk_heaphdr *) env, (duk_heaphdr *) func, (long) regbase)); | |
605 | ||
606 | duk_push_hobject(ctx, env); | |
607 | ||
608 | /* assertions: env must be closed in the same thread as where it runs */ | |
609 | #ifdef DUK_USE_ASSERTIONS | |
610 | { | |
611 | /* [... env] */ | |
612 | ||
613 | if (duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_CALLEE)) { | |
614 | DUK_ASSERT(duk_is_object(ctx, -1)); | |
615 | DUK_ASSERT(duk_get_hobject(ctx, -1) == (duk_hobject *) func); | |
616 | } | |
617 | duk_pop(ctx); | |
618 | ||
619 | if (duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_THREAD)) { | |
620 | DUK_ASSERT(duk_is_object(ctx, -1)); | |
621 | DUK_ASSERT(duk_get_hobject(ctx, -1) == (duk_hobject *) thr); | |
622 | } | |
623 | duk_pop(ctx); | |
624 | ||
625 | if (duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_REGBASE)) { | |
626 | DUK_ASSERT(duk_is_number(ctx, -1)); | |
627 | DUK_ASSERT(duk_get_number(ctx, -1) == (double) regbase); | |
628 | } | |
629 | duk_pop(ctx); | |
630 | ||
631 | /* [... env] */ | |
632 | } | |
633 | #endif | |
634 | ||
635 | if (func != NULL && DUK_HOBJECT_IS_COMPILEDFUNCTION(func)) { | |
636 | duk_hobject *varmap; | |
637 | duk_hstring *key; | |
638 | duk_tval *tv; | |
639 | duk_uint_t regnum; | |
640 | ||
641 | /* XXX: additional conditions when to close variables? we don't want to do it | |
642 | * unless the environment may have "escaped" (referenced in a function closure). | |
643 | * With delayed environments, the existence is probably good enough of a check. | |
644 | */ | |
645 | ||
646 | /* XXX: any way to detect faster whether something needs to be closed? | |
647 | * We now look up _Callee and then skip the rest. | |
648 | */ | |
649 | ||
650 | /* Note: we rely on the _Varmap having a bunch of nice properties, like: | |
651 | * - being compacted and unmodified during this process | |
652 | * - not containing an array part | |
653 | * - having correct value types | |
654 | */ | |
655 | ||
656 | /* [... env] */ | |
657 | ||
658 | if (!duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_CALLEE)) { | |
659 | DUK_DDD(DUK_DDDPRINT("env has no callee property, nothing to close; re-delete the control properties just in case")); | |
660 | duk_pop(ctx); | |
661 | goto skip_varmap; | |
662 | } | |
663 | ||
664 | /* [... env callee] */ | |
665 | ||
666 | if (!duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_VARMAP)) { | |
667 | DUK_DDD(DUK_DDDPRINT("callee has no varmap property, nothing to close; delete the control properties")); | |
668 | duk_pop_2(ctx); | |
669 | goto skip_varmap; | |
670 | } | |
671 | varmap = duk_require_hobject(ctx, -1); | |
672 | DUK_ASSERT(varmap != NULL); | |
673 | ||
674 | DUK_DDD(DUK_DDDPRINT("varmap: %!O", (duk_heaphdr *) varmap)); | |
675 | ||
676 | /* [... env callee varmap] */ | |
677 | ||
678 | DUK_DDD(DUK_DDDPRINT("copying bound register values, %ld bound regs", (long) DUK_HOBJECT_GET_ENEXT(varmap))); | |
679 | ||
680 | for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(varmap); i++) { | |
681 | key = DUK_HOBJECT_E_GET_KEY(thr->heap, varmap, i); | |
682 | DUK_ASSERT(key != NULL); /* assume keys are compacted */ | |
683 | ||
684 | DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, varmap, i)); /* assume plain values */ | |
685 | ||
686 | tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, varmap, i); | |
687 | DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv)); /* assume value is a number */ | |
688 | regnum = (duk_uint_t) DUK_TVAL_GET_NUMBER(tv); | |
689 | DUK_ASSERT_DISABLE(regnum >= 0); /* unsigned */ | |
690 | DUK_ASSERT(regnum < ((duk_hcompiledfunction *) func)->nregs); /* regnum is sane */ | |
691 | DUK_ASSERT(thr->valstack + regbase + regnum >= thr->valstack); | |
692 | DUK_ASSERT(thr->valstack + regbase + regnum < thr->valstack_top); | |
693 | ||
694 | /* XXX: slightly awkward */ | |
695 | duk_push_hstring(ctx, key); | |
696 | duk_push_tval(ctx, thr->valstack + regbase + regnum); | |
697 | DUK_DDD(DUK_DDDPRINT("closing identifier '%s' -> reg %ld, value %!T", | |
698 | (const char *) duk_require_string(ctx, -2), | |
699 | (long) regnum, | |
700 | (duk_tval *) duk_get_tval(ctx, -1))); | |
701 | ||
702 | /* [... env callee varmap key val] */ | |
703 | ||
704 | /* if property already exists, overwrites silently */ | |
705 | duk_xdef_prop(ctx, -5, DUK_PROPDESC_FLAGS_WE); /* writable but not deletable */ | |
706 | } | |
707 | ||
708 | duk_pop_2(ctx); | |
709 | ||
710 | /* [... env] */ | |
711 | } | |
712 | ||
713 | skip_varmap: | |
714 | ||
715 | /* [... env] */ | |
716 | ||
717 | duk_del_prop_stridx(ctx, -1, DUK_STRIDX_INT_CALLEE); | |
718 | duk_del_prop_stridx(ctx, -1, DUK_STRIDX_INT_THREAD); | |
719 | duk_del_prop_stridx(ctx, -1, DUK_STRIDX_INT_REGBASE); | |
720 | ||
721 | duk_pop(ctx); | |
722 | ||
723 | DUK_HOBJECT_SET_ENVRECCLOSED(env); | |
724 | ||
725 | DUK_DDD(DUK_DDDPRINT("environment record after being closed: %!O", | |
726 | (duk_heaphdr *) env)); | |
727 | } | |
728 | ||
729 | /* | |
730 | * GETIDREF: a GetIdentifierReference-like helper. | |
731 | * | |
732 | * Provides a parent traversing lookup and a single level lookup | |
733 | * (for HasBinding). | |
734 | * | |
735 | * Instead of returning the value, returns a bunch of values allowing | |
736 | * the caller to read, write, or delete the binding. Value pointers | |
737 | * are duk_tval pointers which can be mutated directly as long as | |
738 | * refcounts are properly updated. Note that any operation which may | |
739 | * reallocate valstacks or compact objects may invalidate the returned | |
740 | * duk_tval (but not object) pointers, so caller must be very careful. | |
741 | * | |
742 | * If starting environment record 'env' is given, 'act' is ignored. | |
743 | * However, if 'env' is NULL, the caller may identify, in 'act', an | |
744 | * activation which hasn't had its declarative environment initialized | |
745 | * yet. The activation registers are then looked up, and its parent | |
746 | * traversed normally. | |
747 | * | |
748 | * The 'out' structure values are only valid if the function returns | |
749 | * success (non-zero). | |
750 | */ | |
751 | ||
752 | /* lookup name from an open declarative record's registers */ | |
753 | DUK_LOCAL | |
754 | duk_bool_t duk__getid_open_decl_env_regs(duk_hthread *thr, | |
755 | duk_hstring *name, | |
756 | duk_hobject *env, | |
757 | duk__id_lookup_result *out) { | |
758 | duk_hthread *env_thr; | |
759 | duk_hobject *env_func; | |
760 | duk_size_t env_regbase; | |
761 | duk_hobject *varmap; | |
762 | duk_tval *tv; | |
763 | duk_size_t reg_rel; | |
764 | duk_size_t idx; | |
765 | ||
766 | DUK_ASSERT(thr != NULL); | |
767 | DUK_ASSERT(name != NULL); | |
768 | DUK_ASSERT(env != NULL); | |
769 | DUK_ASSERT(out != NULL); | |
770 | ||
771 | DUK_ASSERT(DUK_HOBJECT_IS_DECENV(env)); | |
772 | ||
773 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, env, DUK_HTHREAD_STRING_INT_CALLEE(thr)); | |
774 | if (!tv) { | |
775 | /* env is closed, should be missing _Callee, _Thread, _Regbase */ | |
776 | DUK_ASSERT(duk_hobject_find_existing_entry_tval_ptr(thr->heap, env, DUK_HTHREAD_STRING_INT_CALLEE(thr)) == NULL); | |
777 | DUK_ASSERT(duk_hobject_find_existing_entry_tval_ptr(thr->heap, env, DUK_HTHREAD_STRING_INT_THREAD(thr)) == NULL); | |
778 | DUK_ASSERT(duk_hobject_find_existing_entry_tval_ptr(thr->heap, env, DUK_HTHREAD_STRING_INT_REGBASE(thr)) == NULL); | |
779 | return 0; | |
780 | } | |
781 | ||
782 | DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv)); | |
783 | DUK_ASSERT(DUK_TVAL_GET_OBJECT(tv) != NULL); | |
784 | DUK_ASSERT(DUK_HOBJECT_IS_COMPILEDFUNCTION(DUK_TVAL_GET_OBJECT(tv))); | |
785 | env_func = DUK_TVAL_GET_OBJECT(tv); | |
786 | DUK_ASSERT(env_func != NULL); | |
787 | ||
788 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, env_func, DUK_HTHREAD_STRING_INT_VARMAP(thr)); | |
789 | if (!tv) { | |
790 | return 0; | |
791 | } | |
792 | DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv)); | |
793 | varmap = DUK_TVAL_GET_OBJECT(tv); | |
794 | DUK_ASSERT(varmap != NULL); | |
795 | ||
796 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, varmap, name); | |
797 | if (!tv) { | |
798 | return 0; | |
799 | } | |
800 | DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv)); | |
801 | reg_rel = (duk_size_t) DUK_TVAL_GET_NUMBER(tv); | |
802 | DUK_ASSERT_DISABLE(reg_rel >= 0); /* unsigned */ | |
803 | DUK_ASSERT(reg_rel < ((duk_hcompiledfunction *) env_func)->nregs); | |
804 | ||
805 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, env, DUK_HTHREAD_STRING_INT_THREAD(thr)); | |
806 | DUK_ASSERT(tv != NULL); | |
807 | DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv)); | |
808 | DUK_ASSERT(DUK_TVAL_GET_OBJECT(tv) != NULL); | |
809 | DUK_ASSERT(DUK_HOBJECT_IS_THREAD(DUK_TVAL_GET_OBJECT(tv))); | |
810 | env_thr = (duk_hthread *) DUK_TVAL_GET_OBJECT(tv); | |
811 | DUK_ASSERT(env_thr != NULL); | |
812 | ||
813 | /* Note: env_thr != thr is quite possible and normal, so careful | |
814 | * with what thread is used for valstack lookup. | |
815 | */ | |
816 | ||
817 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, env, DUK_HTHREAD_STRING_INT_REGBASE(thr)); | |
818 | DUK_ASSERT(tv != NULL); | |
819 | DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv)); | |
820 | env_regbase = (duk_size_t) DUK_TVAL_GET_NUMBER(tv); | |
821 | ||
822 | idx = env_regbase + reg_rel; | |
823 | tv = env_thr->valstack + idx; | |
824 | DUK_ASSERT(tv >= env_thr->valstack && tv < env_thr->valstack_end); /* XXX: more accurate? */ | |
825 | ||
826 | out->value = tv; | |
827 | out->attrs = DUK_PROPDESC_FLAGS_W; /* registers are mutable, non-deletable */ | |
828 | out->this_binding = NULL; /* implicit this value always undefined for | |
829 | * declarative environment records. | |
830 | */ | |
831 | out->env = env; | |
832 | out->holder = NULL; | |
833 | ||
834 | return 1; | |
835 | } | |
836 | ||
837 | /* lookup name from current activation record's functions' registers */ | |
838 | DUK_LOCAL | |
839 | duk_bool_t duk__getid_activation_regs(duk_hthread *thr, | |
840 | duk_hstring *name, | |
841 | duk_activation *act, | |
842 | duk__id_lookup_result *out) { | |
843 | duk_tval *tv; | |
844 | duk_hobject *func; | |
845 | duk_hobject *varmap; | |
846 | duk_size_t reg_rel; | |
847 | duk_size_t idx; | |
848 | ||
849 | DUK_ASSERT(thr != NULL); | |
850 | DUK_ASSERT(name != NULL); | |
851 | DUK_ASSERT(act != NULL); | |
852 | DUK_ASSERT(out != NULL); | |
853 | ||
854 | func = DUK_ACT_GET_FUNC(act); | |
855 | DUK_ASSERT(func != NULL); | |
856 | DUK_ASSERT(DUK_HOBJECT_HAS_NEWENV(func)); | |
857 | ||
858 | if (!DUK_HOBJECT_IS_COMPILEDFUNCTION(func)) { | |
859 | return 0; | |
860 | } | |
861 | ||
862 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, func, DUK_HTHREAD_STRING_INT_VARMAP(thr)); | |
863 | if (!tv) { | |
864 | return 0; | |
865 | } | |
866 | DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv)); | |
867 | varmap = DUK_TVAL_GET_OBJECT(tv); | |
868 | DUK_ASSERT(varmap != NULL); | |
869 | ||
870 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, varmap, name); | |
871 | if (!tv) { | |
872 | return 0; | |
873 | } | |
874 | DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv)); | |
875 | reg_rel = (duk_size_t) DUK_TVAL_GET_NUMBER(tv); | |
876 | DUK_ASSERT_DISABLE(reg_rel >= 0); | |
877 | DUK_ASSERT(reg_rel < ((duk_hcompiledfunction *) func)->nregs); | |
878 | ||
879 | idx = act->idx_bottom + reg_rel; | |
880 | DUK_ASSERT(idx >= act->idx_bottom); | |
881 | tv = thr->valstack + idx; | |
882 | ||
883 | out->value = tv; | |
884 | out->attrs = DUK_PROPDESC_FLAGS_W; /* registers are mutable, non-deletable */ | |
885 | out->this_binding = NULL; /* implicit this value always undefined for | |
886 | * declarative environment records. | |
887 | */ | |
888 | out->env = NULL; | |
889 | out->holder = NULL; | |
890 | ||
891 | return 1; | |
892 | } | |
893 | ||
894 | DUK_LOCAL | |
895 | duk_bool_t duk__get_identifier_reference(duk_hthread *thr, | |
896 | duk_hobject *env, | |
897 | duk_hstring *name, | |
898 | duk_activation *act, | |
899 | duk_bool_t parents, | |
900 | duk__id_lookup_result *out) { | |
901 | duk_tval *tv; | |
902 | duk_tval *tv_target; | |
903 | duk_tval tv_name; | |
904 | duk_uint_t sanity; | |
905 | ||
906 | DUK_ASSERT(thr != NULL); | |
907 | DUK_ASSERT(env != NULL || act != NULL); | |
908 | DUK_ASSERT(name != NULL); | |
909 | DUK_ASSERT(out != NULL); | |
910 | ||
911 | DUK_ASSERT(!env || DUK_HOBJECT_IS_ENV(env)); | |
912 | DUK_ASSERT(!env || !DUK_HOBJECT_HAS_ARRAY_PART(env)); | |
913 | ||
914 | /* | |
915 | * Conceptually, we look for the identifier binding by starting from | |
916 | * 'env' and following to chain of environment records (represented | |
917 | * by the prototype chain). | |
918 | * | |
919 | * If 'env' is NULL, the current activation does not yet have an | |
920 | * allocated declarative environment record; this should be treated | |
921 | * exactly as if the environment record existed but had no bindings | |
922 | * other than register bindings. | |
923 | * | |
924 | * Note: we assume that with the DUK_HOBJECT_FLAG_NEWENV cleared | |
925 | * the environment will always be initialized immediately; hence | |
926 | * a NULL 'env' should only happen with the flag set. This is the | |
927 | * case for: (1) function calls, and (2) strict, direct eval calls. | |
928 | */ | |
929 | ||
930 | if (env == NULL && act != NULL) { | |
931 | duk_hobject *func; | |
932 | ||
933 | DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference: env is NULL, activation is non-NULL -> " | |
934 | "delayed env case, look up activation regs first")); | |
935 | ||
936 | /* | |
937 | * Try registers | |
938 | */ | |
939 | ||
940 | if (duk__getid_activation_regs(thr, name, act, out)) { | |
941 | DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference successful: " | |
942 | "name=%!O -> value=%!T, attrs=%ld, this=%!T, env=%!O, holder=%!O " | |
943 | "(found from register bindings when env=NULL)", | |
944 | (duk_heaphdr *) name, (duk_tval *) out->value, | |
945 | (long) out->attrs, (duk_tval *) out->this_binding, | |
946 | (duk_heaphdr *) out->env, (duk_heaphdr *) out->holder)); | |
947 | return 1; | |
948 | } | |
949 | ||
950 | DUK_DDD(DUK_DDDPRINT("not found in current activation regs")); | |
951 | ||
952 | /* | |
953 | * Not found in registers, proceed to the parent record. | |
954 | * Here we need to determine what the parent would be, | |
955 | * if 'env' was not NULL (i.e. same logic as when initializing | |
956 | * the record). | |
957 | * | |
958 | * Note that environment initialization is only deferred when | |
959 | * DUK_HOBJECT_HAS_NEWENV is set, and this only happens for: | |
960 | * - Function code | |
961 | * - Strict eval code | |
962 | * | |
963 | * We only need to check _Lexenv here; _Varenv exists only if it | |
964 | * differs from _Lexenv (and thus _Lexenv will also be present). | |
965 | */ | |
966 | ||
967 | if (!parents) { | |
968 | DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference failed, no parent traversal " | |
969 | "(not found from register bindings when env=NULL)")); | |
970 | goto fail_not_found; | |
971 | } | |
972 | ||
973 | func = DUK_ACT_GET_FUNC(act); | |
974 | DUK_ASSERT(func != NULL); | |
975 | DUK_ASSERT(DUK_HOBJECT_HAS_NEWENV(func)); | |
976 | ||
977 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, func, DUK_HTHREAD_STRING_INT_LEXENV(thr)); | |
978 | if (tv) { | |
979 | DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv)); | |
980 | env = DUK_TVAL_GET_OBJECT(tv); | |
981 | } else { | |
982 | DUK_ASSERT(duk_hobject_find_existing_entry_tval_ptr(thr->heap, func, DUK_HTHREAD_STRING_INT_VARENV(thr)) == NULL); | |
983 | env = thr->builtins[DUK_BIDX_GLOBAL_ENV]; | |
984 | } | |
985 | ||
986 | DUK_DDD(DUK_DDDPRINT("continue lookup from env: %!iO", | |
987 | (duk_heaphdr *) env)); | |
988 | } | |
989 | ||
990 | /* | |
991 | * Prototype walking starting from 'env'. | |
992 | * | |
993 | * ('act' is not needed anywhere here.) | |
994 | */ | |
995 | ||
996 | sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY; | |
997 | while (env != NULL) { | |
998 | duk_small_int_t cl; | |
999 | duk_int_t attrs; | |
1000 | ||
1001 | DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference, name=%!O, considering env=%p -> %!iO", | |
1002 | (duk_heaphdr *) name, | |
1003 | (void *) env, | |
1004 | (duk_heaphdr *) env)); | |
1005 | ||
1006 | DUK_ASSERT(env != NULL); | |
1007 | DUK_ASSERT(DUK_HOBJECT_IS_ENV(env)); | |
1008 | DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(env)); | |
1009 | ||
1010 | cl = DUK_HOBJECT_GET_CLASS_NUMBER(env); | |
1011 | DUK_ASSERT(cl == DUK_HOBJECT_CLASS_OBJENV || cl == DUK_HOBJECT_CLASS_DECENV); | |
1012 | if (cl == DUK_HOBJECT_CLASS_DECENV) { | |
1013 | /* | |
1014 | * Declarative environment record. | |
1015 | * | |
1016 | * Identifiers can never be stored in ancestors and are | |
1017 | * always plain values, so we can use an internal helper | |
1018 | * and access the value directly with an duk_tval ptr. | |
1019 | * | |
1020 | * A closed environment is only indicated by it missing | |
1021 | * the "book-keeping" properties required for accessing | |
1022 | * register-bound variables. | |
1023 | */ | |
1024 | ||
1025 | if (DUK_HOBJECT_HAS_ENVRECCLOSED(env)) { | |
1026 | /* already closed */ | |
1027 | goto skip_regs; | |
1028 | } | |
1029 | ||
1030 | if (duk__getid_open_decl_env_regs(thr, name, env, out)) { | |
1031 | DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference successful: " | |
1032 | "name=%!O -> value=%!T, attrs=%ld, this=%!T, env=%!O, holder=%!O " | |
1033 | "(declarative environment record, scope open, found in regs)", | |
1034 | (duk_heaphdr *) name, (duk_tval *) out->value, | |
1035 | (long) out->attrs, (duk_tval *) out->this_binding, | |
1036 | (duk_heaphdr *) out->env, (duk_heaphdr *) out->holder)); | |
1037 | return 1; | |
1038 | } | |
1039 | skip_regs: | |
1040 | ||
1041 | tv = duk_hobject_find_existing_entry_tval_ptr_and_attrs(thr->heap, env, name, &attrs); | |
1042 | if (tv) { | |
1043 | out->value = tv; | |
1044 | out->attrs = attrs; | |
1045 | out->this_binding = NULL; /* implicit this value always undefined for | |
1046 | * declarative environment records. | |
1047 | */ | |
1048 | out->env = env; | |
1049 | out->holder = env; | |
1050 | ||
1051 | DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference successful: " | |
1052 | "name=%!O -> value=%!T, attrs=%ld, this=%!T, env=%!O, holder=%!O " | |
1053 | "(declarative environment record, found in properties)", | |
1054 | (duk_heaphdr *) name, (duk_tval *) out->value, | |
1055 | (long) out->attrs, (duk_tval *) out->this_binding, | |
1056 | (duk_heaphdr *) out->env, (duk_heaphdr *) out->holder)); | |
1057 | return 1; | |
1058 | } | |
1059 | } else { | |
1060 | /* | |
1061 | * Object environment record. | |
1062 | * | |
1063 | * Binding (target) object is an external, uncontrolled object. | |
1064 | * Identifier may be bound in an ancestor property, and may be | |
1065 | * an accessor. Target can also be a Proxy which we must support | |
1066 | * here. | |
1067 | */ | |
1068 | ||
1069 | /* XXX: we could save space by using _Target OR _This. If _Target, assume | |
1070 | * this binding is undefined. If _This, assumes this binding is _This, and | |
1071 | * target is also _This. One property would then be enough. | |
1072 | */ | |
1073 | ||
1074 | duk_hobject *target; | |
1075 | duk_bool_t found; | |
1076 | ||
1077 | DUK_ASSERT(cl == DUK_HOBJECT_CLASS_OBJENV); | |
1078 | ||
1079 | tv_target = duk_hobject_find_existing_entry_tval_ptr(thr->heap, env, DUK_HTHREAD_STRING_INT_TARGET(thr)); | |
1080 | DUK_ASSERT(tv_target != NULL); | |
1081 | DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv_target)); | |
1082 | target = DUK_TVAL_GET_OBJECT(tv_target); | |
1083 | DUK_ASSERT(target != NULL); | |
1084 | ||
1085 | /* Target may be a Proxy or property may be an accessor, so we must | |
1086 | * use an actual, Proxy-aware hasprop check here. | |
1087 | * | |
1088 | * out->holder is NOT set to the actual duk_hobject where the | |
1089 | * property is found, but rather the object binding target object. | |
1090 | */ | |
1091 | ||
1092 | if (DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(target)) { | |
1093 | DUK_ASSERT(name != NULL); | |
1094 | DUK_TVAL_SET_STRING(&tv_name, name); | |
1095 | ||
1096 | found = duk_hobject_hasprop(thr, tv_target, &tv_name); | |
1097 | } else { | |
1098 | /* XXX: duk_hobject_hasprop() would be correct for | |
1099 | * non-Proxy objects too, but it is about ~20-25% | |
1100 | * slower at present so separate code paths for | |
1101 | * Proxy and non-Proxy now. | |
1102 | */ | |
1103 | found = duk_hobject_hasprop_raw(thr, target, name); | |
1104 | } | |
1105 | ||
1106 | if (found) { | |
1107 | out->value = NULL; /* can't get value, may be accessor */ | |
1108 | out->attrs = 0; /* irrelevant when out->value == NULL */ | |
1109 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, env, DUK_HTHREAD_STRING_INT_THIS(thr)); | |
1110 | out->this_binding = tv; /* may be NULL */ | |
1111 | out->env = env; | |
1112 | out->holder = target; | |
1113 | ||
1114 | DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference successful: " | |
1115 | "name=%!O -> value=%!T, attrs=%ld, this=%!T, env=%!O, holder=%!O " | |
1116 | "(object environment record)", | |
1117 | (duk_heaphdr *) name, (duk_tval *) out->value, | |
1118 | (long) out->attrs, (duk_tval *) out->this_binding, | |
1119 | (duk_heaphdr *) out->env, (duk_heaphdr *) out->holder)); | |
1120 | return 1; | |
1121 | } | |
1122 | } | |
1123 | ||
1124 | if (!parents) { | |
1125 | DUK_DDD(DUK_DDDPRINT("duk__get_identifier_reference failed, no parent traversal " | |
1126 | "(not found from first traversed env)")); | |
1127 | goto fail_not_found; | |
1128 | } | |
1129 | ||
1130 | if (sanity-- == 0) { | |
11fdf7f2 | 1131 | DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT); |
7c673cae FG |
1132 | } |
1133 | env = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, env); | |
1134 | }; | |
1135 | ||
1136 | /* | |
1137 | * Not found (even in global object) | |
1138 | */ | |
1139 | ||
1140 | fail_not_found: | |
1141 | return 0; | |
1142 | } | |
1143 | ||
1144 | /* | |
1145 | * HASVAR: check identifier binding from a given environment record | |
1146 | * without traversing its parents. | |
1147 | * | |
1148 | * This primitive is not exposed to user code as such, but is used | |
1149 | * internally for e.g. declaration binding instantiation. | |
1150 | * | |
1151 | * See E5 Sections: | |
1152 | * 10.2.1.1.1 HasBinding(N) | |
1153 | * 10.2.1.2.1 HasBinding(N) | |
1154 | * | |
1155 | * Note: strictness has no bearing on this check. Hence we don't take | |
1156 | * a 'strict' parameter. | |
1157 | */ | |
1158 | ||
1159 | #if 0 /*unused*/ | |
1160 | DUK_INTERNAL | |
1161 | duk_bool_t duk_js_hasvar_envrec(duk_hthread *thr, | |
1162 | duk_hobject *env, | |
1163 | duk_hstring *name) { | |
1164 | duk__id_lookup_result ref; | |
1165 | duk_bool_t parents; | |
1166 | ||
1167 | DUK_DDD(DUK_DDDPRINT("hasvar: thr=%p, env=%p, name=%!O " | |
1168 | "(env -> %!dO)", | |
1169 | (void *) thr, (void *) env, (duk_heaphdr *) name, | |
1170 | (duk_heaphdr *) env)); | |
1171 | ||
1172 | DUK_ASSERT(thr != NULL); | |
1173 | DUK_ASSERT(env != NULL); | |
1174 | DUK_ASSERT(name != NULL); | |
1175 | ||
1176 | DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(env); | |
1177 | DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(name); | |
1178 | ||
1179 | DUK_ASSERT(DUK_HOBJECT_IS_ENV(env)); | |
1180 | DUK_ASSERT(!DUK_HOBJECT_HAS_ARRAY_PART(env)); | |
1181 | ||
1182 | /* lookup results is ignored */ | |
1183 | parents = 0; | |
1184 | return duk__get_identifier_reference(thr, env, name, NULL, parents, &ref); | |
1185 | } | |
1186 | #endif | |
1187 | ||
1188 | /* | |
1189 | * GETVAR | |
1190 | * | |
1191 | * See E5 Sections: | |
1192 | * 11.1.2 Identifier Reference | |
1193 | * 10.3.1 Identifier Resolution | |
1194 | * 11.13.1 Simple Assignment [example of where the Reference is GetValue'd] | |
1195 | * 8.7.1 GetValue (V) | |
1196 | * 8.12.1 [[GetOwnProperty]] (P) | |
1197 | * 8.12.2 [[GetProperty]] (P) | |
1198 | * 8.12.3 [[Get]] (P) | |
1199 | * | |
1200 | * If 'throw' is true, always leaves two values on top of stack: [val this]. | |
1201 | * | |
1202 | * If 'throw' is false, returns 0 if identifier cannot be resolved, and the | |
1203 | * stack will be unaffected in this case. If identifier is resolved, returns | |
1204 | * 1 and leaves [val this] on top of stack. | |
1205 | * | |
1206 | * Note: the 'strict' flag of a reference returned by GetIdentifierReference | |
1207 | * is ignored by GetValue. Hence we don't take a 'strict' parameter. | |
1208 | * | |
1209 | * The 'throw' flag is needed for implementing 'typeof' for an unreferenced | |
1210 | * identifier. An unreference identifier in other contexts generates a | |
1211 | * ReferenceError. | |
1212 | */ | |
1213 | ||
1214 | DUK_LOCAL | |
1215 | duk_bool_t duk__getvar_helper(duk_hthread *thr, | |
1216 | duk_hobject *env, | |
1217 | duk_activation *act, | |
1218 | duk_hstring *name, | |
1219 | duk_bool_t throw_flag) { | |
1220 | duk_context *ctx = (duk_context *) thr; | |
1221 | duk__id_lookup_result ref; | |
1222 | duk_tval tv_tmp_obj; | |
1223 | duk_tval tv_tmp_key; | |
1224 | duk_bool_t parents; | |
1225 | ||
1226 | DUK_DDD(DUK_DDDPRINT("getvar: thr=%p, env=%p, act=%p, name=%!O " | |
1227 | "(env -> %!dO)", | |
1228 | (void *) thr, (void *) env, (void *) act, | |
1229 | (duk_heaphdr *) name, (duk_heaphdr *) env)); | |
1230 | ||
1231 | DUK_ASSERT(thr != NULL); | |
1232 | DUK_ASSERT(name != NULL); | |
1233 | /* env and act may be NULL */ | |
1234 | ||
1235 | DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(env); | |
1236 | DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(name); | |
1237 | ||
1238 | parents = 1; /* follow parent chain */ | |
1239 | if (duk__get_identifier_reference(thr, env, name, act, parents, &ref)) { | |
1240 | if (ref.value) { | |
1241 | DUK_ASSERT(ref.this_binding == NULL); /* always for register bindings */ | |
1242 | duk_push_tval(ctx, ref.value); | |
1243 | duk_push_undefined(ctx); | |
1244 | } else { | |
1245 | DUK_ASSERT(ref.holder != NULL); | |
1246 | ||
1247 | /* Note: getprop may invoke any getter and invalidate any | |
1248 | * duk_tval pointers, so this must be done first. | |
1249 | */ | |
1250 | ||
1251 | if (ref.this_binding) { | |
1252 | duk_push_tval(ctx, ref.this_binding); | |
1253 | } else { | |
1254 | duk_push_undefined(ctx); | |
1255 | } | |
1256 | ||
1257 | DUK_TVAL_SET_OBJECT(&tv_tmp_obj, ref.holder); | |
1258 | DUK_TVAL_SET_STRING(&tv_tmp_key, name); | |
1259 | (void) duk_hobject_getprop(thr, &tv_tmp_obj, &tv_tmp_key); /* [this value] */ | |
1260 | ||
1261 | /* ref.value, ref.this.binding invalidated here by getprop call */ | |
1262 | ||
1263 | duk_insert(ctx, -2); /* [this value] -> [value this] */ | |
1264 | } | |
1265 | ||
1266 | return 1; | |
1267 | } else { | |
1268 | if (throw_flag) { | |
11fdf7f2 TL |
1269 | DUK_ERROR_FMT1(thr, DUK_ERR_REFERENCE_ERROR, |
1270 | "identifier '%s' undefined", | |
1271 | (const char *) DUK_HSTRING_GET_DATA(name)); | |
7c673cae FG |
1272 | } |
1273 | ||
1274 | return 0; | |
1275 | } | |
1276 | } | |
1277 | ||
1278 | DUK_INTERNAL | |
1279 | duk_bool_t duk_js_getvar_envrec(duk_hthread *thr, | |
1280 | duk_hobject *env, | |
1281 | duk_hstring *name, | |
1282 | duk_bool_t throw_flag) { | |
1283 | return duk__getvar_helper(thr, env, NULL, name, throw_flag); | |
1284 | } | |
1285 | ||
1286 | DUK_INTERNAL | |
1287 | duk_bool_t duk_js_getvar_activation(duk_hthread *thr, | |
1288 | duk_activation *act, | |
1289 | duk_hstring *name, | |
1290 | duk_bool_t throw_flag) { | |
1291 | DUK_ASSERT(act != NULL); | |
1292 | return duk__getvar_helper(thr, act->lex_env, act, name, throw_flag); | |
1293 | } | |
1294 | ||
1295 | /* | |
1296 | * PUTVAR | |
1297 | * | |
1298 | * See E5 Sections: | |
1299 | * 11.1.2 Identifier Reference | |
1300 | * 10.3.1 Identifier Resolution | |
1301 | * 11.13.1 Simple Assignment [example of where the Reference is PutValue'd] | |
1302 | * 8.7.2 PutValue (V,W) [see especially step 3.b, undefined -> automatic global in non-strict mode] | |
1303 | * 8.12.4 [[CanPut]] (P) | |
1304 | * 8.12.5 [[Put]] (P) | |
1305 | * | |
1306 | * Note: may invalidate any valstack (or object) duk_tval pointers because | |
1307 | * putting a value may reallocate any object or any valstack. Caller beware. | |
1308 | */ | |
1309 | ||
1310 | DUK_LOCAL | |
1311 | void duk__putvar_helper(duk_hthread *thr, | |
1312 | duk_hobject *env, | |
1313 | duk_activation *act, | |
1314 | duk_hstring *name, | |
1315 | duk_tval *val, | |
1316 | duk_bool_t strict) { | |
1317 | duk__id_lookup_result ref; | |
1318 | duk_tval tv_tmp_obj; | |
1319 | duk_tval tv_tmp_key; | |
1320 | duk_bool_t parents; | |
1321 | ||
1322 | DUK_DDD(DUK_DDDPRINT("putvar: thr=%p, env=%p, act=%p, name=%!O, val=%p, strict=%ld " | |
1323 | "(env -> %!dO, val -> %!T)", | |
1324 | (void *) thr, (void *) env, (void *) act, | |
1325 | (duk_heaphdr *) name, (void *) val, (long) strict, | |
1326 | (duk_heaphdr *) env, (duk_tval *) val)); | |
1327 | ||
1328 | DUK_ASSERT(thr != NULL); | |
1329 | DUK_ASSERT(name != NULL); | |
1330 | DUK_ASSERT(val != NULL); | |
1331 | /* env and act may be NULL */ | |
1332 | ||
1333 | DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(env); | |
1334 | DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(name); | |
1335 | DUK_ASSERT_REFCOUNT_NONZERO_TVAL(val); | |
1336 | ||
1337 | /* | |
1338 | * In strict mode E5 protects 'eval' and 'arguments' from being | |
1339 | * assigned to (or even declared anywhere). Attempt to do so | |
1340 | * should result in a compile time SyntaxError. See the internal | |
1341 | * design documentation for details. | |
1342 | * | |
1343 | * Thus, we should never come here, run-time, for strict code, | |
1344 | * and name 'eval' or 'arguments'. | |
1345 | */ | |
1346 | ||
1347 | DUK_ASSERT(!strict || | |
1348 | (name != DUK_HTHREAD_STRING_EVAL(thr) && | |
1349 | name != DUK_HTHREAD_STRING_LC_ARGUMENTS(thr))); | |
1350 | ||
1351 | /* | |
1352 | * Lookup variable and update in-place if found. | |
1353 | */ | |
1354 | ||
1355 | parents = 1; /* follow parent chain */ | |
1356 | ||
1357 | if (duk__get_identifier_reference(thr, env, name, act, parents, &ref)) { | |
1358 | if (ref.value && (ref.attrs & DUK_PROPDESC_FLAG_WRITABLE)) { | |
1359 | /* Update duk_tval in-place if pointer provided and the | |
1360 | * property is writable. If the property is not writable | |
1361 | * (immutable binding), use duk_hobject_putprop() which | |
1362 | * will respect mutability. | |
1363 | */ | |
7c673cae FG |
1364 | duk_tval *tv_val; |
1365 | ||
1366 | DUK_ASSERT(ref.this_binding == NULL); /* always for register bindings */ | |
1367 | ||
1368 | tv_val = ref.value; | |
1369 | DUK_ASSERT(tv_val != NULL); | |
11fdf7f2 | 1370 | DUK_TVAL_SET_TVAL_UPDREF(thr, tv_val, val); /* side effects */ |
7c673cae FG |
1371 | |
1372 | /* ref.value and ref.this_binding invalidated here */ | |
1373 | } else { | |
1374 | DUK_ASSERT(ref.holder != NULL); | |
1375 | ||
1376 | DUK_TVAL_SET_OBJECT(&tv_tmp_obj, ref.holder); | |
1377 | DUK_TVAL_SET_STRING(&tv_tmp_key, name); | |
1378 | (void) duk_hobject_putprop(thr, &tv_tmp_obj, &tv_tmp_key, val, strict); | |
1379 | ||
1380 | /* ref.value and ref.this_binding invalidated here */ | |
1381 | } | |
1382 | ||
1383 | return; | |
1384 | } | |
1385 | ||
1386 | /* | |
1387 | * Not found: write to global object (non-strict) or ReferenceError | |
1388 | * (strict); see E5 Section 8.7.2, step 3. | |
1389 | */ | |
1390 | ||
1391 | if (strict) { | |
1392 | DUK_DDD(DUK_DDDPRINT("identifier binding not found, strict => reference error")); | |
1393 | DUK_ERROR(thr, DUK_ERR_REFERENCE_ERROR, "identifier not defined"); | |
1394 | } | |
1395 | ||
1396 | DUK_DDD(DUK_DDDPRINT("identifier binding not found, not strict => set to global")); | |
1397 | ||
1398 | DUK_TVAL_SET_OBJECT(&tv_tmp_obj, thr->builtins[DUK_BIDX_GLOBAL]); | |
1399 | DUK_TVAL_SET_STRING(&tv_tmp_key, name); | |
1400 | (void) duk_hobject_putprop(thr, &tv_tmp_obj, &tv_tmp_key, val, 0); /* 0 = no throw */ | |
1401 | ||
1402 | /* NB: 'val' may be invalidated here because put_value may realloc valstack, | |
1403 | * caller beware. | |
1404 | */ | |
1405 | } | |
1406 | ||
1407 | DUK_INTERNAL | |
1408 | void duk_js_putvar_envrec(duk_hthread *thr, | |
1409 | duk_hobject *env, | |
1410 | duk_hstring *name, | |
1411 | duk_tval *val, | |
1412 | duk_bool_t strict) { | |
1413 | duk__putvar_helper(thr, env, NULL, name, val, strict); | |
1414 | } | |
1415 | ||
1416 | DUK_INTERNAL | |
1417 | void duk_js_putvar_activation(duk_hthread *thr, | |
1418 | duk_activation *act, | |
1419 | duk_hstring *name, | |
1420 | duk_tval *val, | |
1421 | duk_bool_t strict) { | |
1422 | DUK_ASSERT(act != NULL); | |
1423 | duk__putvar_helper(thr, act->lex_env, act, name, val, strict); | |
1424 | } | |
1425 | ||
1426 | /* | |
1427 | * DELVAR | |
1428 | * | |
1429 | * See E5 Sections: | |
1430 | * 11.4.1 The delete operator | |
1431 | * 10.2.1.1.5 DeleteBinding (N) [declarative environment record] | |
1432 | * 10.2.1.2.5 DeleteBinding (N) [object environment record] | |
1433 | * | |
1434 | * Variable bindings established inside eval() are deletable (configurable), | |
1435 | * other bindings are not, including variables declared in global level. | |
1436 | * Registers are always non-deletable, and the deletion of other bindings | |
1437 | * is controlled by the configurable flag. | |
1438 | * | |
1439 | * For strict mode code, the 'delete' operator should fail with a compile | |
1440 | * time SyntaxError if applied to identifiers. Hence, no strict mode | |
1441 | * run-time deletion of identifiers should ever happen. This function | |
1442 | * should never be called from strict mode code! | |
1443 | */ | |
1444 | ||
1445 | DUK_LOCAL | |
1446 | duk_bool_t duk__delvar_helper(duk_hthread *thr, | |
1447 | duk_hobject *env, | |
1448 | duk_activation *act, | |
1449 | duk_hstring *name) { | |
1450 | duk__id_lookup_result ref; | |
1451 | duk_bool_t parents; | |
1452 | ||
1453 | DUK_DDD(DUK_DDDPRINT("delvar: thr=%p, env=%p, act=%p, name=%!O " | |
1454 | "(env -> %!dO)", | |
1455 | (void *) thr, (void *) env, (void *) act, | |
1456 | (duk_heaphdr *) name, (duk_heaphdr *) env)); | |
1457 | ||
1458 | DUK_ASSERT(thr != NULL); | |
1459 | DUK_ASSERT(name != NULL); | |
1460 | /* env and act may be NULL */ | |
1461 | ||
1462 | DUK_ASSERT_REFCOUNT_NONZERO_HEAPHDR(name); | |
1463 | ||
1464 | parents = 1; /* follow parent chain */ | |
1465 | ||
1466 | if (duk__get_identifier_reference(thr, env, name, act, parents, &ref)) { | |
1467 | if (ref.value && !(ref.attrs & DUK_PROPDESC_FLAG_CONFIGURABLE)) { | |
1468 | /* Identifier found in registers (always non-deletable) | |
1469 | * or declarative environment record and non-configurable. | |
1470 | */ | |
1471 | return 0; | |
1472 | } | |
1473 | DUK_ASSERT(ref.holder != NULL); | |
1474 | ||
1475 | return duk_hobject_delprop_raw(thr, ref.holder, name, 0); | |
1476 | } | |
1477 | ||
1478 | /* | |
1479 | * Not found (even in global object). | |
1480 | * | |
1481 | * In non-strict mode this is a silent SUCCESS (!), see E5 Section 11.4.1, | |
1482 | * step 3.b. In strict mode this case is a compile time SyntaxError so | |
1483 | * we should not come here. | |
1484 | */ | |
1485 | ||
1486 | DUK_DDD(DUK_DDDPRINT("identifier to be deleted not found: name=%!O " | |
1487 | "(treated as silent success)", | |
1488 | (duk_heaphdr *) name)); | |
1489 | return 1; | |
1490 | } | |
1491 | ||
1492 | #if 0 /*unused*/ | |
1493 | DUK_INTERNAL | |
1494 | duk_bool_t duk_js_delvar_envrec(duk_hthread *thr, | |
1495 | duk_hobject *env, | |
1496 | duk_hstring *name) { | |
1497 | return duk__delvar_helper(thr, env, NULL, name); | |
1498 | } | |
1499 | #endif | |
1500 | ||
1501 | DUK_INTERNAL | |
1502 | duk_bool_t duk_js_delvar_activation(duk_hthread *thr, | |
1503 | duk_activation *act, | |
1504 | duk_hstring *name) { | |
1505 | DUK_ASSERT(act != NULL); | |
1506 | return duk__delvar_helper(thr, act->lex_env, act, name); | |
1507 | } | |
1508 | ||
1509 | /* | |
1510 | * DECLVAR | |
1511 | * | |
1512 | * See E5 Sections: | |
1513 | * 10.4.3 Entering Function Code | |
1514 | * 10.5 Declaration Binding Instantion | |
1515 | * 12.2 Variable Statement | |
1516 | * 11.1.2 Identifier Reference | |
1517 | * 10.3.1 Identifier Resolution | |
1518 | * | |
1519 | * Variable declaration behavior is mainly discussed in Section 10.5, | |
1520 | * and is not discussed in the execution semantics (Sections 11-13). | |
1521 | * | |
1522 | * Conceptually declarations happen when code (global, eval, function) | |
1523 | * is entered, before any user code is executed. In practice, register- | |
1524 | * bound identifiers are 'declared' automatically (by virtue of being | |
1525 | * allocated to registers with the initial value 'undefined'). Other | |
1526 | * identifiers are declared in the function prologue with this primitive. | |
1527 | * | |
1528 | * Since non-register bindings eventually back to an internal object's | |
1529 | * properties, the 'prop_flags' argument is used to specify binding | |
1530 | * type: | |
1531 | * | |
1532 | * - Immutable binding: set DUK_PROPDESC_FLAG_WRITABLE to false | |
1533 | * - Non-deletable binding: set DUK_PROPDESC_FLAG_CONFIGURABLE to false | |
1534 | * - The flag DUK_PROPDESC_FLAG_ENUMERABLE should be set, although it | |
1535 | * doesn't really matter for internal objects | |
1536 | * | |
1537 | * All bindings are non-deletable mutable bindings except: | |
1538 | * | |
1539 | * - Declarations in eval code (mutable, deletable) | |
1540 | * - 'arguments' binding in strict function code (immutable) | |
1541 | * - Function name binding of a function expression (immutable) | |
1542 | * | |
1543 | * Declarations may go to declarative environment records (always | |
1544 | * so for functions), but may also go to object environment records | |
1545 | * (e.g. global code). The global object environment has special | |
1546 | * behavior when re-declaring a function (but not a variable); see | |
1547 | * E5.1 specification, Section 10.5, step 5.e. | |
1548 | * | |
1549 | * Declarations always go to the 'top-most' environment record, i.e. | |
1550 | * we never check the record chain. It's not an error even if a | |
1551 | * property (even an immutable or non-deletable one) of the same name | |
1552 | * already exists. | |
1553 | * | |
1554 | * If a declared variable already exists, its value needs to be updated | |
1555 | * (if possible). Returns 1 if a PUTVAR needs to be done by the caller; | |
1556 | * otherwise returns 0. | |
1557 | */ | |
1558 | ||
1559 | DUK_LOCAL | |
1560 | duk_bool_t duk__declvar_helper(duk_hthread *thr, | |
1561 | duk_hobject *env, | |
1562 | duk_hstring *name, | |
1563 | duk_tval *val, | |
1564 | duk_small_int_t prop_flags, | |
1565 | duk_bool_t is_func_decl) { | |
1566 | duk_context *ctx = (duk_context *) thr; | |
1567 | duk_hobject *holder; | |
1568 | duk_bool_t parents; | |
1569 | duk__id_lookup_result ref; | |
1570 | duk_tval *tv; | |
1571 | ||
1572 | DUK_DDD(DUK_DDDPRINT("declvar: thr=%p, env=%p, name=%!O, val=%!T, prop_flags=0x%08lx, is_func_decl=%ld " | |
1573 | "(env -> %!iO)", | |
1574 | (void *) thr, (void *) env, (duk_heaphdr *) name, | |
1575 | (duk_tval *) val, (unsigned long) prop_flags, | |
1576 | (unsigned int) is_func_decl, (duk_heaphdr *) env)); | |
1577 | ||
1578 | DUK_ASSERT(thr != NULL); | |
1579 | DUK_ASSERT(env != NULL); | |
1580 | DUK_ASSERT(name != NULL); | |
1581 | DUK_ASSERT(val != NULL); | |
1582 | ||
1583 | /* Note: in strict mode the compiler should reject explicit | |
1584 | * declaration of 'eval' or 'arguments'. However, internal | |
1585 | * bytecode may declare 'arguments' in the function prologue. | |
1586 | * We don't bother checking (or asserting) for these now. | |
1587 | */ | |
1588 | ||
1589 | /* Note: val is a stable duk_tval pointer. The caller makes | |
1590 | * a value copy into its stack frame, so 'tv_val' is not subject | |
1591 | * to side effects here. | |
1592 | */ | |
1593 | ||
1594 | /* | |
1595 | * Check whether already declared. | |
1596 | * | |
1597 | * We need to check whether the binding exists in the environment | |
1598 | * without walking its parents. However, we still need to check | |
1599 | * register-bound identifiers and the prototype chain of an object | |
1600 | * environment target object. | |
1601 | */ | |
1602 | ||
1603 | parents = 0; /* just check 'env' */ | |
1604 | if (duk__get_identifier_reference(thr, env, name, NULL, parents, &ref)) { | |
1605 | duk_int_t e_idx; | |
1606 | duk_int_t h_idx; | |
1607 | duk_small_int_t flags; | |
1608 | ||
1609 | /* | |
1610 | * Variable already declared, ignore re-declaration. | |
1611 | * The only exception is the updated behavior of E5.1 for | |
1612 | * global function declarations, E5.1 Section 10.5, step 5.e. | |
1613 | * This behavior does not apply to global variable declarations. | |
1614 | */ | |
1615 | ||
1616 | if (!(is_func_decl && env == thr->builtins[DUK_BIDX_GLOBAL_ENV])) { | |
1617 | DUK_DDD(DUK_DDDPRINT("re-declare a binding, ignoring")); | |
1618 | return 1; /* 1 -> needs a PUTVAR */ | |
1619 | } | |
1620 | ||
1621 | /* | |
1622 | * Special behavior in E5.1. | |
1623 | * | |
1624 | * Note that even though parents == 0, the conflicting property | |
1625 | * may be an inherited property (currently our global object's | |
1626 | * prototype is Object.prototype). Step 5.e first operates on | |
1627 | * the existing property (which is potentially in an ancestor) | |
1628 | * and then defines a new property in the global object (and | |
1629 | * never modifies the ancestor). | |
1630 | * | |
1631 | * Also note that this logic would become even more complicated | |
1632 | * if the conflicting property might be a virtual one. Object | |
1633 | * prototype has no virtual properties, though. | |
1634 | * | |
1635 | * XXX: this is now very awkward, rework. | |
1636 | */ | |
1637 | ||
1638 | DUK_DDD(DUK_DDDPRINT("re-declare a function binding in global object, " | |
1639 | "updated E5.1 processing")); | |
1640 | ||
1641 | DUK_ASSERT(ref.holder != NULL); | |
1642 | holder = ref.holder; | |
1643 | ||
1644 | /* holder will be set to the target object, not the actual object | |
1645 | * where the property was found (see duk__get_identifier_reference()). | |
1646 | */ | |
1647 | DUK_ASSERT(DUK_HOBJECT_GET_CLASS_NUMBER(holder) == DUK_HOBJECT_CLASS_GLOBAL); | |
1648 | DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARRAY(holder)); /* global object doesn't have array part */ | |
1649 | ||
1650 | /* XXX: use a helper for prototype traversal; no loop check here */ | |
1651 | /* must be found: was found earlier, and cannot be inherited */ | |
1652 | for (;;) { | |
1653 | DUK_ASSERT(holder != NULL); | |
1654 | duk_hobject_find_existing_entry(thr->heap, holder, name, &e_idx, &h_idx); | |
1655 | if (e_idx >= 0) { | |
1656 | break; | |
1657 | } | |
1658 | /* SCANBUILD: NULL pointer dereference, doesn't actually trigger, | |
1659 | * asserted above. | |
1660 | */ | |
1661 | holder = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, holder); | |
1662 | } | |
1663 | DUK_ASSERT(holder != NULL); | |
1664 | DUK_ASSERT(e_idx >= 0); | |
1665 | /* SCANBUILD: scan-build produces a NULL pointer dereference warning | |
1666 | * below; it never actually triggers because holder is actually never | |
1667 | * NULL. | |
1668 | */ | |
1669 | ||
1670 | /* ref.holder is global object, holder is the object with the | |
1671 | * conflicting property. | |
1672 | */ | |
1673 | ||
1674 | flags = DUK_HOBJECT_E_GET_FLAGS(thr->heap, holder, e_idx); | |
1675 | if (!(flags & DUK_PROPDESC_FLAG_CONFIGURABLE)) { | |
1676 | if (flags & DUK_PROPDESC_FLAG_ACCESSOR) { | |
1677 | DUK_DDD(DUK_DDDPRINT("existing property is a non-configurable " | |
1678 | "accessor -> reject")); | |
1679 | goto fail_existing_attributes; | |
1680 | } | |
1681 | if (!((flags & DUK_PROPDESC_FLAG_WRITABLE) && | |
1682 | (flags & DUK_PROPDESC_FLAG_ENUMERABLE))) { | |
1683 | DUK_DDD(DUK_DDDPRINT("existing property is a non-configurable " | |
1684 | "plain property which is not writable and " | |
1685 | "enumerable -> reject")); | |
1686 | goto fail_existing_attributes; | |
1687 | } | |
1688 | ||
1689 | DUK_DDD(DUK_DDDPRINT("existing property is not configurable but " | |
1690 | "is plain, enumerable, and writable -> " | |
1691 | "allow redeclaration")); | |
1692 | } | |
1693 | ||
1694 | if (holder == ref.holder) { | |
1695 | /* XXX: if duk_hobject_define_property_internal() was updated | |
1696 | * to handle a pre-existing accessor property, this would be | |
1697 | * a simple call (like for the ancestor case). | |
1698 | */ | |
1699 | DUK_DDD(DUK_DDDPRINT("redefine, offending property in global object itself")); | |
1700 | ||
1701 | if (flags & DUK_PROPDESC_FLAG_ACCESSOR) { | |
1702 | duk_hobject *tmp; | |
1703 | ||
1704 | tmp = DUK_HOBJECT_E_GET_VALUE_GETTER(thr->heap, holder, e_idx); | |
1705 | DUK_HOBJECT_E_SET_VALUE_GETTER(thr->heap, holder, e_idx, NULL); | |
1706 | DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp); | |
1707 | DUK_UNREF(tmp); | |
1708 | tmp = DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, holder, e_idx); | |
1709 | DUK_HOBJECT_E_SET_VALUE_SETTER(thr->heap, holder, e_idx, NULL); | |
1710 | DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp); | |
1711 | DUK_UNREF(tmp); | |
1712 | } else { | |
7c673cae | 1713 | tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, holder, e_idx); |
11fdf7f2 | 1714 | DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv); |
7c673cae FG |
1715 | } |
1716 | ||
1717 | /* Here val would be potentially invalid if we didn't make | |
1718 | * a value copy at the caller. | |
1719 | */ | |
1720 | ||
1721 | tv = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, holder, e_idx); | |
1722 | DUK_TVAL_SET_TVAL(tv, val); | |
1723 | DUK_TVAL_INCREF(thr, tv); | |
1724 | DUK_HOBJECT_E_SET_FLAGS(thr->heap, holder, e_idx, prop_flags); | |
1725 | ||
1726 | DUK_DDD(DUK_DDDPRINT("updated global binding, final result: " | |
1727 | "value -> %!T, prop_flags=0x%08lx", | |
1728 | (duk_tval *) DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, holder, e_idx), | |
1729 | (unsigned long) prop_flags)); | |
1730 | } else { | |
1731 | DUK_DDD(DUK_DDDPRINT("redefine, offending property in ancestor")); | |
1732 | ||
1733 | DUK_ASSERT(ref.holder == thr->builtins[DUK_BIDX_GLOBAL]); | |
1734 | duk_push_tval(ctx, val); | |
1735 | duk_hobject_define_property_internal(thr, ref.holder, name, prop_flags); | |
1736 | } | |
1737 | ||
1738 | return 0; | |
1739 | } | |
1740 | ||
1741 | /* | |
1742 | * Not found (in registers or record objects). Declare | |
1743 | * to current variable environment. | |
1744 | */ | |
1745 | ||
1746 | /* | |
1747 | * Get holder object | |
1748 | */ | |
1749 | ||
1750 | if (DUK_HOBJECT_IS_DECENV(env)) { | |
1751 | holder = env; | |
1752 | } else { | |
1753 | DUK_ASSERT(DUK_HOBJECT_IS_OBJENV(env)); | |
1754 | ||
1755 | tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, env, DUK_HTHREAD_STRING_INT_TARGET(thr)); | |
1756 | DUK_ASSERT(tv != NULL); | |
1757 | DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv)); | |
1758 | holder = DUK_TVAL_GET_OBJECT(tv); | |
1759 | DUK_ASSERT(holder != NULL); | |
1760 | } | |
1761 | ||
1762 | /* | |
1763 | * Define new property | |
1764 | * | |
1765 | * Note: this may fail if the holder is not extensible. | |
1766 | */ | |
1767 | ||
1768 | /* XXX: this is awkward as we use an internal method which doesn't handle | |
1769 | * extensibility etc correctly. Basically we'd want to do a [[DefineOwnProperty]] | |
1770 | * or Object.defineProperty() here. | |
1771 | */ | |
1772 | ||
1773 | if (!DUK_HOBJECT_HAS_EXTENSIBLE(holder)) { | |
1774 | goto fail_not_extensible; | |
1775 | } | |
1776 | ||
1777 | duk_push_hobject(ctx, holder); | |
1778 | duk_push_hstring(ctx, name); | |
1779 | duk_push_tval(ctx, val); | |
1780 | duk_xdef_prop(ctx, -3, prop_flags); /* [holder name val] -> [holder] */ | |
1781 | duk_pop(ctx); | |
1782 | ||
1783 | return 0; | |
1784 | ||
1785 | fail_existing_attributes: | |
1786 | fail_not_extensible: | |
11fdf7f2 | 1787 | DUK_ERROR_TYPE(thr, "declaration failed"); |
7c673cae FG |
1788 | return 0; |
1789 | } | |
1790 | ||
1791 | DUK_INTERNAL | |
1792 | duk_bool_t duk_js_declvar_activation(duk_hthread *thr, | |
1793 | duk_activation *act, | |
1794 | duk_hstring *name, | |
1795 | duk_tval *val, | |
1796 | duk_small_int_t prop_flags, | |
1797 | duk_bool_t is_func_decl) { | |
1798 | duk_hobject *env; | |
1799 | duk_tval tv_val_copy; | |
11fdf7f2 TL |
1800 | duk_size_t act_off; |
1801 | ||
1802 | DUK_ASSERT(act != NULL); | |
1803 | act_off = (duk_size_t) ((duk_uint8_t *) act - (duk_uint8_t *) thr->callstack); | |
7c673cae FG |
1804 | |
1805 | /* | |
1806 | * Make a value copy of the input val. This ensures that | |
1807 | * side effects cannot invalidate the pointer. | |
1808 | */ | |
1809 | ||
1810 | DUK_TVAL_SET_TVAL(&tv_val_copy, val); | |
1811 | val = &tv_val_copy; | |
1812 | ||
1813 | /* | |
1814 | * Delayed env creation check | |
1815 | */ | |
1816 | ||
1817 | if (!act->var_env) { | |
1818 | DUK_ASSERT(act->lex_env == NULL); | |
1819 | duk_js_init_activation_environment_records_delayed(thr, act); | |
11fdf7f2 | 1820 | act = (duk_activation *) ((duk_uint8_t *) thr->callstack + act_off); |
7c673cae FG |
1821 | } |
1822 | DUK_ASSERT(act->lex_env != NULL); | |
1823 | DUK_ASSERT(act->var_env != NULL); | |
1824 | ||
1825 | env = act->var_env; | |
1826 | DUK_ASSERT(env != NULL); | |
1827 | DUK_ASSERT(DUK_HOBJECT_IS_ENV(env)); | |
1828 | ||
1829 | return duk__declvar_helper(thr, env, name, val, prop_flags, is_func_decl); | |
1830 | } |