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1 | /* |
2 | ** $Id: lparser.c,v 2.130.1.1 2013/04/12 18:48:47 roberto Exp $ | |
3 | ** Lua Parser | |
4 | ** See Copyright Notice in lua.h | |
5 | */ | |
6 | ||
7 | #define lparser_c | |
8 | #define LUA_CORE | |
9 | ||
10 | #include <sys/lua/lua.h> | |
11 | ||
12 | #include "lcode.h" | |
13 | #include "ldebug.h" | |
14 | #include "ldo.h" | |
15 | #include "lfunc.h" | |
16 | #include "llex.h" | |
17 | #include "lmem.h" | |
18 | #include "lobject.h" | |
19 | #include "lopcodes.h" | |
20 | #include "lparser.h" | |
21 | #include "lstate.h" | |
22 | #include "lstring.h" | |
23 | #include "ltable.h" | |
24 | ||
25 | ||
26 | ||
27 | /* maximum number of local variables per function (must be smaller | |
28 | than 250, due to the bytecode format) */ | |
29 | #define MAXVARS 200 | |
30 | ||
31 | ||
32 | #define hasmultret(k) ((k) == VCALL || (k) == VVARARG) | |
33 | ||
34 | ||
35 | ||
36 | /* | |
37 | ** nodes for block list (list of active blocks) | |
38 | */ | |
39 | typedef struct BlockCnt { | |
40 | struct BlockCnt *previous; /* chain */ | |
41 | short firstlabel; /* index of first label in this block */ | |
42 | short firstgoto; /* index of first pending goto in this block */ | |
43 | lu_byte nactvar; /* # active locals outside the block */ | |
44 | lu_byte upval; /* true if some variable in the block is an upvalue */ | |
45 | lu_byte isloop; /* true if `block' is a loop */ | |
46 | } BlockCnt; | |
47 | ||
48 | ||
49 | ||
50 | /* | |
51 | ** prototypes for recursive non-terminal functions | |
52 | */ | |
53 | static void statement (LexState *ls); | |
54 | static void expr (LexState *ls, expdesc *v); | |
55 | ||
56 | ||
57 | static void anchor_token (LexState *ls) { | |
58 | /* last token from outer function must be EOS */ | |
59 | lua_assert(ls->fs != NULL || ls->t.token == TK_EOS); | |
60 | if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) { | |
61 | TString *ts = ls->t.seminfo.ts; | |
62 | luaX_newstring(ls, getstr(ts), ts->tsv.len); | |
63 | } | |
64 | } | |
65 | ||
66 | ||
67 | /* semantic error */ | |
68 | static l_noret semerror (LexState *ls, const char *msg) { | |
69 | ls->t.token = 0; /* remove 'near to' from final message */ | |
70 | luaX_syntaxerror(ls, msg); | |
71 | } | |
72 | ||
73 | ||
74 | static l_noret error_expected (LexState *ls, int token) { | |
75 | luaX_syntaxerror(ls, | |
76 | luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token))); | |
77 | } | |
78 | ||
79 | ||
80 | static l_noret errorlimit (FuncState *fs, int limit, const char *what) { | |
81 | lua_State *L = fs->ls->L; | |
82 | const char *msg; | |
83 | int line = fs->f->linedefined; | |
84 | const char *where = (line == 0) | |
85 | ? "main function" | |
86 | : luaO_pushfstring(L, "function at line %d", line); | |
87 | msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s", | |
88 | what, limit, where); | |
89 | luaX_syntaxerror(fs->ls, msg); | |
90 | } | |
91 | ||
92 | ||
93 | static void checklimit (FuncState *fs, int v, int l, const char *what) { | |
94 | if (v > l) errorlimit(fs, l, what); | |
95 | } | |
96 | ||
97 | ||
98 | static int testnext (LexState *ls, int c) { | |
99 | if (ls->t.token == c) { | |
100 | luaX_next(ls); | |
101 | return 1; | |
102 | } | |
103 | else return 0; | |
104 | } | |
105 | ||
106 | ||
107 | static void check (LexState *ls, int c) { | |
108 | if (ls->t.token != c) | |
109 | error_expected(ls, c); | |
110 | } | |
111 | ||
112 | ||
113 | static void checknext (LexState *ls, int c) { | |
114 | check(ls, c); | |
115 | luaX_next(ls); | |
116 | } | |
117 | ||
118 | ||
119 | #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); } | |
120 | ||
121 | ||
122 | ||
123 | static void check_match (LexState *ls, int what, int who, int where) { | |
124 | if (!testnext(ls, what)) { | |
125 | if (where == ls->linenumber) | |
126 | error_expected(ls, what); | |
127 | else { | |
128 | luaX_syntaxerror(ls, luaO_pushfstring(ls->L, | |
129 | "%s expected (to close %s at line %d)", | |
130 | luaX_token2str(ls, what), luaX_token2str(ls, who), where)); | |
131 | } | |
132 | } | |
133 | } | |
134 | ||
135 | ||
136 | static TString *str_checkname (LexState *ls) { | |
137 | TString *ts; | |
138 | check(ls, TK_NAME); | |
139 | ts = ls->t.seminfo.ts; | |
140 | luaX_next(ls); | |
141 | return ts; | |
142 | } | |
143 | ||
144 | ||
145 | static void init_exp (expdesc *e, expkind k, int i) { | |
146 | e->f = e->t = NO_JUMP; | |
147 | e->k = k; | |
148 | e->u.info = i; | |
149 | } | |
150 | ||
151 | ||
152 | static void codestring (LexState *ls, expdesc *e, TString *s) { | |
153 | init_exp(e, VK, luaK_stringK(ls->fs, s)); | |
154 | } | |
155 | ||
156 | ||
157 | static void checkname (LexState *ls, expdesc *e) { | |
158 | codestring(ls, e, str_checkname(ls)); | |
159 | } | |
160 | ||
161 | ||
162 | static int registerlocalvar (LexState *ls, TString *varname) { | |
163 | FuncState *fs = ls->fs; | |
164 | Proto *f = fs->f; | |
165 | int oldsize = f->sizelocvars; | |
166 | luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars, | |
167 | LocVar, SHRT_MAX, "local variables"); | |
168 | while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL; | |
169 | f->locvars[fs->nlocvars].varname = varname; | |
170 | luaC_objbarrier(ls->L, f, varname); | |
171 | return fs->nlocvars++; | |
172 | } | |
173 | ||
174 | ||
175 | static void new_localvar (LexState *ls, TString *name) { | |
176 | FuncState *fs = ls->fs; | |
177 | Dyndata *dyd = ls->dyd; | |
178 | int reg = registerlocalvar(ls, name); | |
179 | checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal, | |
180 | MAXVARS, "local variables"); | |
181 | luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1, | |
182 | dyd->actvar.size, Vardesc, MAX_INT, "local variables"); | |
183 | dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg); | |
184 | } | |
185 | ||
186 | ||
187 | static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) { | |
188 | new_localvar(ls, luaX_newstring(ls, name, sz)); | |
189 | } | |
190 | ||
191 | #define new_localvarliteral(ls,v) \ | |
192 | new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1) | |
193 | ||
194 | ||
195 | static LocVar *getlocvar (FuncState *fs, int i) { | |
196 | int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx; | |
197 | lua_assert(idx < fs->nlocvars); | |
198 | return &fs->f->locvars[idx]; | |
199 | } | |
200 | ||
201 | ||
202 | static void adjustlocalvars (LexState *ls, int nvars) { | |
203 | FuncState *fs = ls->fs; | |
204 | fs->nactvar = cast_byte(fs->nactvar + nvars); | |
205 | for (; nvars; nvars--) { | |
206 | getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc; | |
207 | } | |
208 | } | |
209 | ||
210 | ||
211 | static void removevars (FuncState *fs, int tolevel) { | |
212 | fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel); | |
213 | while (fs->nactvar > tolevel) | |
214 | getlocvar(fs, --fs->nactvar)->endpc = fs->pc; | |
215 | } | |
216 | ||
217 | ||
218 | static int searchupvalue (FuncState *fs, TString *name) { | |
219 | int i; | |
220 | Upvaldesc *up = fs->f->upvalues; | |
221 | for (i = 0; i < fs->nups; i++) { | |
222 | if (luaS_eqstr(up[i].name, name)) return i; | |
223 | } | |
224 | return -1; /* not found */ | |
225 | } | |
226 | ||
227 | ||
228 | static int newupvalue (FuncState *fs, TString *name, expdesc *v) { | |
229 | Proto *f = fs->f; | |
230 | int oldsize = f->sizeupvalues; | |
231 | checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues"); | |
232 | luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues, | |
233 | Upvaldesc, MAXUPVAL, "upvalues"); | |
234 | while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL; | |
235 | f->upvalues[fs->nups].instack = (v->k == VLOCAL); | |
236 | f->upvalues[fs->nups].idx = cast_byte(v->u.info); | |
237 | f->upvalues[fs->nups].name = name; | |
238 | luaC_objbarrier(fs->ls->L, f, name); | |
239 | return fs->nups++; | |
240 | } | |
241 | ||
242 | ||
243 | static int searchvar (FuncState *fs, TString *n) { | |
244 | int i; | |
245 | for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) { | |
246 | if (luaS_eqstr(n, getlocvar(fs, i)->varname)) | |
247 | return i; | |
248 | } | |
249 | return -1; /* not found */ | |
250 | } | |
251 | ||
252 | ||
253 | /* | |
254 | Mark block where variable at given level was defined | |
255 | (to emit close instructions later). | |
256 | */ | |
257 | static void markupval (FuncState *fs, int level) { | |
258 | BlockCnt *bl = fs->bl; | |
259 | while (bl->nactvar > level) bl = bl->previous; | |
260 | bl->upval = 1; | |
261 | } | |
262 | ||
263 | ||
264 | /* | |
265 | Find variable with given name 'n'. If it is an upvalue, add this | |
266 | upvalue into all intermediate functions. | |
267 | */ | |
268 | static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { | |
269 | if (fs == NULL) /* no more levels? */ | |
270 | return VVOID; /* default is global */ | |
271 | else { | |
272 | int v = searchvar(fs, n); /* look up locals at current level */ | |
273 | if (v >= 0) { /* found? */ | |
274 | init_exp(var, VLOCAL, v); /* variable is local */ | |
275 | if (!base) | |
276 | markupval(fs, v); /* local will be used as an upval */ | |
277 | return VLOCAL; | |
278 | } | |
279 | else { /* not found as local at current level; try upvalues */ | |
280 | int idx = searchupvalue(fs, n); /* try existing upvalues */ | |
281 | if (idx < 0) { /* not found? */ | |
282 | if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */ | |
283 | return VVOID; /* not found; is a global */ | |
284 | /* else was LOCAL or UPVAL */ | |
285 | idx = newupvalue(fs, n, var); /* will be a new upvalue */ | |
286 | } | |
287 | init_exp(var, VUPVAL, idx); | |
288 | return VUPVAL; | |
289 | } | |
290 | } | |
291 | } | |
292 | ||
293 | ||
294 | static void singlevar (LexState *ls, expdesc *var) { | |
295 | TString *varname = str_checkname(ls); | |
296 | FuncState *fs = ls->fs; | |
297 | if (singlevaraux(fs, varname, var, 1) == VVOID) { /* global name? */ | |
298 | expdesc key; | |
299 | singlevaraux(fs, ls->envn, var, 1); /* get environment variable */ | |
300 | lua_assert(var->k == VLOCAL || var->k == VUPVAL); | |
301 | codestring(ls, &key, varname); /* key is variable name */ | |
302 | luaK_indexed(fs, var, &key); /* env[varname] */ | |
303 | } | |
304 | } | |
305 | ||
306 | ||
307 | static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { | |
308 | FuncState *fs = ls->fs; | |
309 | int extra = nvars - nexps; | |
310 | if (hasmultret(e->k)) { | |
311 | extra++; /* includes call itself */ | |
312 | if (extra < 0) extra = 0; | |
313 | luaK_setreturns(fs, e, extra); /* last exp. provides the difference */ | |
314 | if (extra > 1) luaK_reserveregs(fs, extra-1); | |
315 | } | |
316 | else { | |
317 | if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */ | |
318 | if (extra > 0) { | |
319 | int reg = fs->freereg; | |
320 | luaK_reserveregs(fs, extra); | |
321 | luaK_nil(fs, reg, extra); | |
322 | } | |
323 | } | |
324 | } | |
325 | ||
326 | ||
327 | static void enterlevel (LexState *ls) { | |
328 | lua_State *L = ls->L; | |
329 | ++L->nCcalls; | |
330 | checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels"); | |
331 | } | |
332 | ||
333 | ||
334 | #define leavelevel(ls) ((ls)->L->nCcalls--) | |
335 | ||
336 | ||
337 | static void closegoto (LexState *ls, int g, Labeldesc *label) { | |
338 | int i; | |
339 | FuncState *fs = ls->fs; | |
340 | Labellist *gl = &ls->dyd->gt; | |
341 | Labeldesc *gt = &gl->arr[g]; | |
342 | lua_assert(luaS_eqstr(gt->name, label->name)); | |
343 | if (gt->nactvar < label->nactvar) { | |
344 | TString *vname = getlocvar(fs, gt->nactvar)->varname; | |
345 | const char *msg = luaO_pushfstring(ls->L, | |
346 | "<goto %s> at line %d jumps into the scope of local " LUA_QS, | |
347 | getstr(gt->name), gt->line, getstr(vname)); | |
348 | semerror(ls, msg); | |
349 | } | |
350 | luaK_patchlist(fs, gt->pc, label->pc); | |
351 | /* remove goto from pending list */ | |
352 | for (i = g; i < gl->n - 1; i++) | |
353 | gl->arr[i] = gl->arr[i + 1]; | |
354 | gl->n--; | |
355 | } | |
356 | ||
357 | ||
358 | /* | |
359 | ** try to close a goto with existing labels; this solves backward jumps | |
360 | */ | |
361 | static int findlabel (LexState *ls, int g) { | |
362 | int i; | |
363 | BlockCnt *bl = ls->fs->bl; | |
364 | Dyndata *dyd = ls->dyd; | |
365 | Labeldesc *gt = &dyd->gt.arr[g]; | |
366 | /* check labels in current block for a match */ | |
367 | for (i = bl->firstlabel; i < dyd->label.n; i++) { | |
368 | Labeldesc *lb = &dyd->label.arr[i]; | |
369 | if (luaS_eqstr(lb->name, gt->name)) { /* correct label? */ | |
370 | if (gt->nactvar > lb->nactvar && | |
371 | (bl->upval || dyd->label.n > bl->firstlabel)) | |
372 | luaK_patchclose(ls->fs, gt->pc, lb->nactvar); | |
373 | closegoto(ls, g, lb); /* close it */ | |
374 | return 1; | |
375 | } | |
376 | } | |
377 | return 0; /* label not found; cannot close goto */ | |
378 | } | |
379 | ||
380 | ||
381 | static int newlabelentry (LexState *ls, Labellist *l, TString *name, | |
382 | int line, int pc) { | |
383 | int n = l->n; | |
384 | luaM_growvector(ls->L, l->arr, n, l->size, | |
385 | Labeldesc, SHRT_MAX, "labels/gotos"); | |
386 | l->arr[n].name = name; | |
387 | l->arr[n].line = line; | |
388 | l->arr[n].nactvar = ls->fs->nactvar; | |
389 | l->arr[n].pc = pc; | |
390 | l->n++; | |
391 | return n; | |
392 | } | |
393 | ||
394 | ||
395 | /* | |
396 | ** check whether new label 'lb' matches any pending gotos in current | |
397 | ** block; solves forward jumps | |
398 | */ | |
399 | static void findgotos (LexState *ls, Labeldesc *lb) { | |
400 | Labellist *gl = &ls->dyd->gt; | |
401 | int i = ls->fs->bl->firstgoto; | |
402 | while (i < gl->n) { | |
403 | if (luaS_eqstr(gl->arr[i].name, lb->name)) | |
404 | closegoto(ls, i, lb); | |
405 | else | |
406 | i++; | |
407 | } | |
408 | } | |
409 | ||
410 | ||
411 | /* | |
412 | ** "export" pending gotos to outer level, to check them against | |
413 | ** outer labels; if the block being exited has upvalues, and | |
414 | ** the goto exits the scope of any variable (which can be the | |
415 | ** upvalue), close those variables being exited. | |
416 | */ | |
417 | static void movegotosout (FuncState *fs, BlockCnt *bl) { | |
418 | int i = bl->firstgoto; | |
419 | Labellist *gl = &fs->ls->dyd->gt; | |
420 | /* correct pending gotos to current block and try to close it | |
421 | with visible labels */ | |
422 | while (i < gl->n) { | |
423 | Labeldesc *gt = &gl->arr[i]; | |
424 | if (gt->nactvar > bl->nactvar) { | |
425 | if (bl->upval) | |
426 | luaK_patchclose(fs, gt->pc, bl->nactvar); | |
427 | gt->nactvar = bl->nactvar; | |
428 | } | |
429 | if (!findlabel(fs->ls, i)) | |
430 | i++; /* move to next one */ | |
431 | } | |
432 | } | |
433 | ||
434 | ||
435 | static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) { | |
436 | bl->isloop = isloop; | |
437 | bl->nactvar = fs->nactvar; | |
438 | bl->firstlabel = fs->ls->dyd->label.n; | |
439 | bl->firstgoto = fs->ls->dyd->gt.n; | |
440 | bl->upval = 0; | |
441 | bl->previous = fs->bl; | |
442 | fs->bl = bl; | |
443 | lua_assert(fs->freereg == fs->nactvar); | |
444 | } | |
445 | ||
446 | ||
447 | /* | |
448 | ** create a label named "break" to resolve break statements | |
449 | */ | |
450 | static void breaklabel (LexState *ls) { | |
451 | TString *n = luaS_new(ls->L, "break"); | |
452 | int l = newlabelentry(ls, &ls->dyd->label, n, 0, ls->fs->pc); | |
453 | findgotos(ls, &ls->dyd->label.arr[l]); | |
454 | } | |
455 | ||
456 | /* | |
457 | ** generates an error for an undefined 'goto'; choose appropriate | |
458 | ** message when label name is a reserved word (which can only be 'break') | |
459 | */ | |
460 | static l_noret undefgoto (LexState *ls, Labeldesc *gt) { | |
461 | const char *msg = isreserved(gt->name) | |
462 | ? "<%s> at line %d not inside a loop" | |
463 | : "no visible label " LUA_QS " for <goto> at line %d"; | |
464 | msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line); | |
465 | semerror(ls, msg); | |
466 | } | |
467 | ||
468 | ||
469 | static void leaveblock (FuncState *fs) { | |
470 | BlockCnt *bl = fs->bl; | |
471 | LexState *ls = fs->ls; | |
472 | if (bl->previous && bl->upval) { | |
473 | /* create a 'jump to here' to close upvalues */ | |
474 | int j = luaK_jump(fs); | |
475 | luaK_patchclose(fs, j, bl->nactvar); | |
476 | luaK_patchtohere(fs, j); | |
477 | } | |
478 | if (bl->isloop) | |
479 | breaklabel(ls); /* close pending breaks */ | |
480 | fs->bl = bl->previous; | |
481 | removevars(fs, bl->nactvar); | |
482 | lua_assert(bl->nactvar == fs->nactvar); | |
483 | fs->freereg = fs->nactvar; /* free registers */ | |
484 | ls->dyd->label.n = bl->firstlabel; /* remove local labels */ | |
485 | if (bl->previous) /* inner block? */ | |
486 | movegotosout(fs, bl); /* update pending gotos to outer block */ | |
487 | else if (bl->firstgoto < ls->dyd->gt.n) /* pending gotos in outer block? */ | |
488 | undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]); /* error */ | |
489 | } | |
490 | ||
491 | ||
492 | /* | |
493 | ** adds a new prototype into list of prototypes | |
494 | */ | |
495 | static Proto *addprototype (LexState *ls) { | |
496 | Proto *clp; | |
497 | lua_State *L = ls->L; | |
498 | FuncState *fs = ls->fs; | |
499 | Proto *f = fs->f; /* prototype of current function */ | |
500 | if (fs->np >= f->sizep) { | |
501 | int oldsize = f->sizep; | |
502 | luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions"); | |
503 | while (oldsize < f->sizep) f->p[oldsize++] = NULL; | |
504 | } | |
505 | f->p[fs->np++] = clp = luaF_newproto(L); | |
506 | luaC_objbarrier(L, f, clp); | |
507 | return clp; | |
508 | } | |
509 | ||
510 | ||
511 | /* | |
512 | ** codes instruction to create new closure in parent function. | |
513 | ** The OP_CLOSURE instruction must use the last available register, | |
514 | ** so that, if it invokes the GC, the GC knows which registers | |
515 | ** are in use at that time. | |
516 | */ | |
517 | static void codeclosure (LexState *ls, expdesc *v) { | |
518 | FuncState *fs = ls->fs->prev; | |
519 | init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1)); | |
520 | luaK_exp2nextreg(fs, v); /* fix it at the last register */ | |
521 | } | |
522 | ||
523 | ||
524 | static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) { | |
525 | lua_State *L = ls->L; | |
526 | Proto *f; | |
527 | fs->prev = ls->fs; /* linked list of funcstates */ | |
528 | fs->ls = ls; | |
529 | ls->fs = fs; | |
530 | fs->pc = 0; | |
531 | fs->lasttarget = 0; | |
532 | fs->jpc = NO_JUMP; | |
533 | fs->freereg = 0; | |
534 | fs->nk = 0; | |
535 | fs->np = 0; | |
536 | fs->nups = 0; | |
537 | fs->nlocvars = 0; | |
538 | fs->nactvar = 0; | |
539 | fs->firstlocal = ls->dyd->actvar.n; | |
540 | fs->bl = NULL; | |
541 | f = fs->f; | |
542 | f->source = ls->source; | |
543 | f->maxstacksize = 2; /* registers 0/1 are always valid */ | |
544 | fs->h = luaH_new(L); | |
545 | /* anchor table of constants (to avoid being collected) */ | |
546 | sethvalue2s(L, L->top, fs->h); | |
547 | incr_top(L); | |
548 | enterblock(fs, bl, 0); | |
549 | } | |
550 | ||
551 | ||
552 | static void close_func (LexState *ls) { | |
553 | lua_State *L = ls->L; | |
554 | FuncState *fs = ls->fs; | |
555 | Proto *f = fs->f; | |
556 | luaK_ret(fs, 0, 0); /* final return */ | |
557 | leaveblock(fs); | |
558 | luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction); | |
559 | f->sizecode = fs->pc; | |
560 | luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int); | |
561 | f->sizelineinfo = fs->pc; | |
562 | luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue); | |
563 | f->sizek = fs->nk; | |
564 | luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *); | |
565 | f->sizep = fs->np; | |
566 | luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar); | |
567 | f->sizelocvars = fs->nlocvars; | |
568 | luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc); | |
569 | f->sizeupvalues = fs->nups; | |
570 | lua_assert(fs->bl == NULL); | |
571 | ls->fs = fs->prev; | |
572 | /* last token read was anchored in defunct function; must re-anchor it */ | |
573 | anchor_token(ls); | |
574 | L->top--; /* pop table of constants */ | |
575 | luaC_checkGC(L); | |
576 | } | |
577 | ||
578 | ||
579 | ||
580 | /*============================================================*/ | |
581 | /* GRAMMAR RULES */ | |
582 | /*============================================================*/ | |
583 | ||
584 | ||
585 | /* | |
586 | ** check whether current token is in the follow set of a block. | |
587 | ** 'until' closes syntactical blocks, but do not close scope, | |
588 | ** so it handled in separate. | |
589 | */ | |
590 | static int block_follow (LexState *ls, int withuntil) { | |
591 | switch (ls->t.token) { | |
592 | case TK_ELSE: case TK_ELSEIF: | |
593 | case TK_END: case TK_EOS: | |
594 | return 1; | |
595 | case TK_UNTIL: return withuntil; | |
596 | default: return 0; | |
597 | } | |
598 | } | |
599 | ||
600 | ||
601 | /* | |
602 | * by inlining statlist() and test_then_block() we cut back the | |
603 | * native stack usage per nested C call from 272 bytes to 152 | |
604 | * which allows us to stay within budget for 8K kernel stacks | |
605 | */ | |
606 | __attribute__((always_inline)) inline | |
607 | static void statlist (LexState *ls) { | |
608 | /* statlist -> { stat [`;'] } */ | |
609 | while (!block_follow(ls, 1)) { | |
610 | if (ls->t.token == TK_RETURN) { | |
611 | statement(ls); | |
612 | return; /* 'return' must be last statement */ | |
613 | } | |
614 | statement(ls); | |
615 | } | |
616 | } | |
617 | ||
618 | ||
619 | static void fieldsel (LexState *ls, expdesc *v) { | |
620 | /* fieldsel -> ['.' | ':'] NAME */ | |
621 | FuncState *fs = ls->fs; | |
622 | expdesc key; | |
623 | luaK_exp2anyregup(fs, v); | |
624 | luaX_next(ls); /* skip the dot or colon */ | |
625 | checkname(ls, &key); | |
626 | luaK_indexed(fs, v, &key); | |
627 | } | |
628 | ||
629 | ||
630 | static void yindex (LexState *ls, expdesc *v) { | |
631 | /* index -> '[' expr ']' */ | |
632 | luaX_next(ls); /* skip the '[' */ | |
633 | expr(ls, v); | |
634 | luaK_exp2val(ls->fs, v); | |
635 | checknext(ls, ']'); | |
636 | } | |
637 | ||
638 | ||
639 | /* | |
640 | ** {====================================================================== | |
641 | ** Rules for Constructors | |
642 | ** ======================================================================= | |
643 | */ | |
644 | ||
645 | ||
646 | struct ConsControl { | |
647 | expdesc v; /* last list item read */ | |
648 | expdesc *t; /* table descriptor */ | |
649 | int nh; /* total number of `record' elements */ | |
650 | int na; /* total number of array elements */ | |
651 | int tostore; /* number of array elements pending to be stored */ | |
652 | }; | |
653 | ||
654 | ||
655 | static void recfield (LexState *ls, struct ConsControl *cc) { | |
656 | /* recfield -> (NAME | `['exp1`]') = exp1 */ | |
657 | FuncState *fs = ls->fs; | |
658 | int reg = ls->fs->freereg; | |
659 | expdesc key, val; | |
660 | int rkkey; | |
661 | if (ls->t.token == TK_NAME) { | |
662 | checklimit(fs, cc->nh, MAX_INT, "items in a constructor"); | |
663 | checkname(ls, &key); | |
664 | } | |
665 | else /* ls->t.token == '[' */ | |
666 | yindex(ls, &key); | |
667 | cc->nh++; | |
668 | checknext(ls, '='); | |
669 | rkkey = luaK_exp2RK(fs, &key); | |
670 | expr(ls, &val); | |
671 | luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val)); | |
672 | fs->freereg = reg; /* free registers */ | |
673 | } | |
674 | ||
675 | ||
676 | static void closelistfield (FuncState *fs, struct ConsControl *cc) { | |
677 | if (cc->v.k == VVOID) return; /* there is no list item */ | |
678 | luaK_exp2nextreg(fs, &cc->v); | |
679 | cc->v.k = VVOID; | |
680 | if (cc->tostore == LFIELDS_PER_FLUSH) { | |
681 | luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */ | |
682 | cc->tostore = 0; /* no more items pending */ | |
683 | } | |
684 | } | |
685 | ||
686 | ||
687 | static void lastlistfield (FuncState *fs, struct ConsControl *cc) { | |
688 | if (cc->tostore == 0) return; | |
689 | if (hasmultret(cc->v.k)) { | |
690 | luaK_setmultret(fs, &cc->v); | |
691 | luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET); | |
692 | cc->na--; /* do not count last expression (unknown number of elements) */ | |
693 | } | |
694 | else { | |
695 | if (cc->v.k != VVOID) | |
696 | luaK_exp2nextreg(fs, &cc->v); | |
697 | luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); | |
698 | } | |
699 | } | |
700 | ||
701 | ||
702 | static void listfield (LexState *ls, struct ConsControl *cc) { | |
703 | /* listfield -> exp */ | |
704 | expr(ls, &cc->v); | |
705 | checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor"); | |
706 | cc->na++; | |
707 | cc->tostore++; | |
708 | } | |
709 | ||
710 | ||
711 | static void field (LexState *ls, struct ConsControl *cc) { | |
712 | /* field -> listfield | recfield */ | |
713 | switch(ls->t.token) { | |
714 | case TK_NAME: { /* may be 'listfield' or 'recfield' */ | |
715 | if (luaX_lookahead(ls) != '=') /* expression? */ | |
716 | listfield(ls, cc); | |
717 | else | |
718 | recfield(ls, cc); | |
719 | break; | |
720 | } | |
721 | case '[': { | |
722 | recfield(ls, cc); | |
723 | break; | |
724 | } | |
725 | default: { | |
726 | listfield(ls, cc); | |
727 | break; | |
728 | } | |
729 | } | |
730 | } | |
731 | ||
732 | ||
733 | static void constructor (LexState *ls, expdesc *t) { | |
734 | /* constructor -> '{' [ field { sep field } [sep] ] '}' | |
735 | sep -> ',' | ';' */ | |
736 | FuncState *fs = ls->fs; | |
737 | int line = ls->linenumber; | |
738 | int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0); | |
739 | struct ConsControl cc; | |
740 | cc.na = cc.nh = cc.tostore = 0; | |
741 | cc.t = t; | |
742 | init_exp(t, VRELOCABLE, pc); | |
743 | init_exp(&cc.v, VVOID, 0); /* no value (yet) */ | |
744 | luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */ | |
745 | checknext(ls, '{'); | |
746 | do { | |
747 | lua_assert(cc.v.k == VVOID || cc.tostore > 0); | |
748 | if (ls->t.token == '}') break; | |
749 | closelistfield(fs, &cc); | |
750 | field(ls, &cc); | |
751 | } while (testnext(ls, ',') || testnext(ls, ';')); | |
752 | check_match(ls, '}', '{', line); | |
753 | lastlistfield(fs, &cc); | |
754 | SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */ | |
755 | SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */ | |
756 | } | |
757 | ||
758 | /* }====================================================================== */ | |
759 | ||
760 | ||
761 | ||
762 | static void parlist (LexState *ls) { | |
763 | /* parlist -> [ param { `,' param } ] */ | |
764 | FuncState *fs = ls->fs; | |
765 | Proto *f = fs->f; | |
766 | int nparams = 0; | |
767 | f->is_vararg = 0; | |
768 | if (ls->t.token != ')') { /* is `parlist' not empty? */ | |
769 | do { | |
770 | switch (ls->t.token) { | |
771 | case TK_NAME: { /* param -> NAME */ | |
772 | new_localvar(ls, str_checkname(ls)); | |
773 | nparams++; | |
774 | break; | |
775 | } | |
776 | case TK_DOTS: { /* param -> `...' */ | |
777 | luaX_next(ls); | |
778 | f->is_vararg = 1; | |
779 | break; | |
780 | } | |
781 | default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected"); | |
782 | } | |
783 | } while (!f->is_vararg && testnext(ls, ',')); | |
784 | } | |
785 | adjustlocalvars(ls, nparams); | |
786 | f->numparams = cast_byte(fs->nactvar); | |
787 | luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */ | |
788 | } | |
789 | ||
790 | ||
791 | static void body (LexState *ls, expdesc *e, int ismethod, int line) { | |
792 | /* body -> `(' parlist `)' block END */ | |
793 | FuncState new_fs; | |
794 | BlockCnt bl; | |
795 | new_fs.f = addprototype(ls); | |
796 | new_fs.f->linedefined = line; | |
797 | open_func(ls, &new_fs, &bl); | |
798 | checknext(ls, '('); | |
799 | if (ismethod) { | |
800 | new_localvarliteral(ls, "self"); /* create 'self' parameter */ | |
801 | adjustlocalvars(ls, 1); | |
802 | } | |
803 | parlist(ls); | |
804 | checknext(ls, ')'); | |
805 | statlist(ls); | |
806 | new_fs.f->lastlinedefined = ls->linenumber; | |
807 | check_match(ls, TK_END, TK_FUNCTION, line); | |
808 | codeclosure(ls, e); | |
809 | close_func(ls); | |
810 | } | |
811 | ||
812 | ||
813 | static int explist (LexState *ls, expdesc *v) { | |
814 | /* explist -> expr { `,' expr } */ | |
815 | int n = 1; /* at least one expression */ | |
816 | expr(ls, v); | |
817 | while (testnext(ls, ',')) { | |
818 | luaK_exp2nextreg(ls->fs, v); | |
819 | expr(ls, v); | |
820 | n++; | |
821 | } | |
822 | return n; | |
823 | } | |
824 | ||
825 | ||
826 | static void funcargs (LexState *ls, expdesc *f, int line) { | |
827 | FuncState *fs = ls->fs; | |
828 | expdesc args; | |
829 | int base, nparams; | |
830 | switch (ls->t.token) { | |
831 | case '(': { /* funcargs -> `(' [ explist ] `)' */ | |
832 | luaX_next(ls); | |
833 | if (ls->t.token == ')') /* arg list is empty? */ | |
834 | args.k = VVOID; | |
835 | else { | |
836 | explist(ls, &args); | |
837 | luaK_setmultret(fs, &args); | |
838 | } | |
839 | check_match(ls, ')', '(', line); | |
840 | break; | |
841 | } | |
842 | case '{': { /* funcargs -> constructor */ | |
843 | constructor(ls, &args); | |
844 | break; | |
845 | } | |
846 | case TK_STRING: { /* funcargs -> STRING */ | |
847 | codestring(ls, &args, ls->t.seminfo.ts); | |
848 | luaX_next(ls); /* must use `seminfo' before `next' */ | |
849 | break; | |
850 | } | |
851 | default: { | |
852 | luaX_syntaxerror(ls, "function arguments expected"); | |
853 | } | |
854 | } | |
855 | lua_assert(f->k == VNONRELOC); | |
856 | base = f->u.info; /* base register for call */ | |
857 | if (hasmultret(args.k)) | |
858 | nparams = LUA_MULTRET; /* open call */ | |
859 | else { | |
860 | if (args.k != VVOID) | |
861 | luaK_exp2nextreg(fs, &args); /* close last argument */ | |
862 | nparams = fs->freereg - (base+1); | |
863 | } | |
864 | init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2)); | |
865 | luaK_fixline(fs, line); | |
866 | fs->freereg = base+1; /* call remove function and arguments and leaves | |
867 | (unless changed) one result */ | |
868 | } | |
869 | ||
870 | ||
871 | ||
872 | ||
873 | /* | |
874 | ** {====================================================================== | |
875 | ** Expression parsing | |
876 | ** ======================================================================= | |
877 | */ | |
878 | ||
879 | ||
880 | static void primaryexp (LexState *ls, expdesc *v) { | |
881 | /* primaryexp -> NAME | '(' expr ')' */ | |
882 | switch (ls->t.token) { | |
883 | case '(': { | |
884 | int line = ls->linenumber; | |
885 | luaX_next(ls); | |
886 | expr(ls, v); | |
887 | check_match(ls, ')', '(', line); | |
888 | luaK_dischargevars(ls->fs, v); | |
889 | return; | |
890 | } | |
891 | case TK_NAME: { | |
892 | singlevar(ls, v); | |
893 | return; | |
894 | } | |
895 | default: { | |
896 | luaX_syntaxerror(ls, "unexpected symbol"); | |
897 | } | |
898 | } | |
899 | } | |
900 | ||
901 | ||
902 | static void suffixedexp (LexState *ls, expdesc *v) { | |
903 | /* suffixedexp -> | |
904 | primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */ | |
905 | FuncState *fs = ls->fs; | |
906 | int line = ls->linenumber; | |
907 | primaryexp(ls, v); | |
908 | for (;;) { | |
909 | switch (ls->t.token) { | |
910 | case '.': { /* fieldsel */ | |
911 | fieldsel(ls, v); | |
912 | break; | |
913 | } | |
914 | case '[': { /* `[' exp1 `]' */ | |
915 | expdesc key; | |
916 | luaK_exp2anyregup(fs, v); | |
917 | yindex(ls, &key); | |
918 | luaK_indexed(fs, v, &key); | |
919 | break; | |
920 | } | |
921 | case ':': { /* `:' NAME funcargs */ | |
922 | expdesc key; | |
923 | luaX_next(ls); | |
924 | checkname(ls, &key); | |
925 | luaK_self(fs, v, &key); | |
926 | funcargs(ls, v, line); | |
927 | break; | |
928 | } | |
929 | case '(': case TK_STRING: case '{': { /* funcargs */ | |
930 | luaK_exp2nextreg(fs, v); | |
931 | funcargs(ls, v, line); | |
932 | break; | |
933 | } | |
934 | default: return; | |
935 | } | |
936 | } | |
937 | } | |
938 | ||
939 | ||
940 | static void simpleexp (LexState *ls, expdesc *v) { | |
941 | /* simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... | | |
942 | constructor | FUNCTION body | suffixedexp */ | |
943 | switch (ls->t.token) { | |
944 | case TK_NUMBER: { | |
945 | init_exp(v, VKNUM, 0); | |
946 | v->u.nval = ls->t.seminfo.r; | |
947 | break; | |
948 | } | |
949 | case TK_STRING: { | |
950 | codestring(ls, v, ls->t.seminfo.ts); | |
951 | break; | |
952 | } | |
953 | case TK_NIL: { | |
954 | init_exp(v, VNIL, 0); | |
955 | break; | |
956 | } | |
957 | case TK_TRUE: { | |
958 | init_exp(v, VTRUE, 0); | |
959 | break; | |
960 | } | |
961 | case TK_FALSE: { | |
962 | init_exp(v, VFALSE, 0); | |
963 | break; | |
964 | } | |
965 | case TK_DOTS: { /* vararg */ | |
966 | FuncState *fs = ls->fs; | |
967 | check_condition(ls, fs->f->is_vararg, | |
968 | "cannot use " LUA_QL("...") " outside a vararg function"); | |
969 | init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0)); | |
970 | break; | |
971 | } | |
972 | case '{': { /* constructor */ | |
973 | constructor(ls, v); | |
974 | return; | |
975 | } | |
976 | case TK_FUNCTION: { | |
977 | luaX_next(ls); | |
978 | body(ls, v, 0, ls->linenumber); | |
979 | return; | |
980 | } | |
981 | default: { | |
982 | suffixedexp(ls, v); | |
983 | return; | |
984 | } | |
985 | } | |
986 | luaX_next(ls); | |
987 | } | |
988 | ||
989 | ||
990 | static UnOpr getunopr (int op) { | |
991 | switch (op) { | |
992 | case TK_NOT: return OPR_NOT; | |
993 | case '-': return OPR_MINUS; | |
994 | case '#': return OPR_LEN; | |
995 | default: return OPR_NOUNOPR; | |
996 | } | |
997 | } | |
998 | ||
999 | ||
1000 | static BinOpr getbinopr (int op) { | |
1001 | switch (op) { | |
1002 | case '+': return OPR_ADD; | |
1003 | case '-': return OPR_SUB; | |
1004 | case '*': return OPR_MUL; | |
1005 | case '/': return OPR_DIV; | |
1006 | case '%': return OPR_MOD; | |
1007 | case '^': return OPR_POW; | |
1008 | case TK_CONCAT: return OPR_CONCAT; | |
1009 | case TK_NE: return OPR_NE; | |
1010 | case TK_EQ: return OPR_EQ; | |
1011 | case '<': return OPR_LT; | |
1012 | case TK_LE: return OPR_LE; | |
1013 | case '>': return OPR_GT; | |
1014 | case TK_GE: return OPR_GE; | |
1015 | case TK_AND: return OPR_AND; | |
1016 | case TK_OR: return OPR_OR; | |
1017 | default: return OPR_NOBINOPR; | |
1018 | } | |
1019 | } | |
1020 | ||
1021 | ||
1022 | static const struct { | |
1023 | lu_byte left; /* left priority for each binary operator */ | |
1024 | lu_byte right; /* right priority */ | |
1025 | } priority[] = { /* ORDER OPR */ | |
1026 | {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `*' `/' `%' */ | |
1027 | {10, 9}, {5, 4}, /* ^, .. (right associative) */ | |
1028 | {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */ | |
1029 | {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */ | |
1030 | {2, 2}, {1, 1} /* and, or */ | |
1031 | }; | |
1032 | ||
1033 | #define UNARY_PRIORITY 8 /* priority for unary operators */ | |
1034 | ||
1035 | ||
1036 | /* | |
1037 | ** subexpr -> (simpleexp | unop subexpr) { binop subexpr } | |
1038 | ** where `binop' is any binary operator with a priority higher than `limit' | |
1039 | */ | |
1040 | static BinOpr subexpr (LexState *ls, expdesc *v, int limit) { | |
1041 | BinOpr op; | |
1042 | UnOpr uop; | |
1043 | enterlevel(ls); | |
1044 | uop = getunopr(ls->t.token); | |
1045 | if (uop != OPR_NOUNOPR) { | |
1046 | int line = ls->linenumber; | |
1047 | luaX_next(ls); | |
1048 | subexpr(ls, v, UNARY_PRIORITY); | |
1049 | luaK_prefix(ls->fs, uop, v, line); | |
1050 | } | |
1051 | else simpleexp(ls, v); | |
1052 | /* expand while operators have priorities higher than `limit' */ | |
1053 | op = getbinopr(ls->t.token); | |
1054 | while (op != OPR_NOBINOPR && priority[op].left > limit) { | |
1055 | expdesc v2; | |
1056 | BinOpr nextop; | |
1057 | int line = ls->linenumber; | |
1058 | luaX_next(ls); | |
1059 | luaK_infix(ls->fs, op, v); | |
1060 | /* read sub-expression with higher priority */ | |
1061 | nextop = subexpr(ls, &v2, priority[op].right); | |
1062 | luaK_posfix(ls->fs, op, v, &v2, line); | |
1063 | op = nextop; | |
1064 | } | |
1065 | leavelevel(ls); | |
1066 | return op; /* return first untreated operator */ | |
1067 | } | |
1068 | ||
1069 | ||
1070 | static void expr (LexState *ls, expdesc *v) { | |
1071 | subexpr(ls, v, 0); | |
1072 | } | |
1073 | ||
1074 | /* }==================================================================== */ | |
1075 | ||
1076 | ||
1077 | ||
1078 | /* | |
1079 | ** {====================================================================== | |
1080 | ** Rules for Statements | |
1081 | ** ======================================================================= | |
1082 | */ | |
1083 | ||
1084 | ||
1085 | static void block (LexState *ls) { | |
1086 | /* block -> statlist */ | |
1087 | FuncState *fs = ls->fs; | |
1088 | BlockCnt bl; | |
1089 | enterblock(fs, &bl, 0); | |
1090 | statlist(ls); | |
1091 | leaveblock(fs); | |
1092 | } | |
1093 | ||
1094 | ||
1095 | /* | |
1096 | ** structure to chain all variables in the left-hand side of an | |
1097 | ** assignment | |
1098 | */ | |
1099 | struct LHS_assign { | |
1100 | struct LHS_assign *prev; | |
1101 | expdesc v; /* variable (global, local, upvalue, or indexed) */ | |
1102 | }; | |
1103 | ||
1104 | ||
1105 | /* | |
1106 | ** check whether, in an assignment to an upvalue/local variable, the | |
1107 | ** upvalue/local variable is begin used in a previous assignment to a | |
1108 | ** table. If so, save original upvalue/local value in a safe place and | |
1109 | ** use this safe copy in the previous assignment. | |
1110 | */ | |
1111 | static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) { | |
1112 | FuncState *fs = ls->fs; | |
1113 | int extra = fs->freereg; /* eventual position to save local variable */ | |
1114 | int conflict = 0; | |
1115 | for (; lh; lh = lh->prev) { /* check all previous assignments */ | |
1116 | if (lh->v.k == VINDEXED) { /* assigning to a table? */ | |
1117 | /* table is the upvalue/local being assigned now? */ | |
1118 | if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) { | |
1119 | conflict = 1; | |
1120 | lh->v.u.ind.vt = VLOCAL; | |
1121 | lh->v.u.ind.t = extra; /* previous assignment will use safe copy */ | |
1122 | } | |
1123 | /* index is the local being assigned? (index cannot be upvalue) */ | |
1124 | if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) { | |
1125 | conflict = 1; | |
1126 | lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */ | |
1127 | } | |
1128 | } | |
1129 | } | |
1130 | if (conflict) { | |
1131 | /* copy upvalue/local value to a temporary (in position 'extra') */ | |
1132 | OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL; | |
1133 | luaK_codeABC(fs, op, extra, v->u.info, 0); | |
1134 | luaK_reserveregs(fs, 1); | |
1135 | } | |
1136 | } | |
1137 | ||
1138 | ||
1139 | static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) { | |
1140 | expdesc e; | |
1141 | check_condition(ls, vkisvar(lh->v.k), "syntax error"); | |
1142 | if (testnext(ls, ',')) { /* assignment -> ',' suffixedexp assignment */ | |
1143 | struct LHS_assign nv; | |
1144 | nv.prev = lh; | |
1145 | suffixedexp(ls, &nv.v); | |
1146 | if (nv.v.k != VINDEXED) | |
1147 | check_conflict(ls, lh, &nv.v); | |
1148 | checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS, | |
1149 | "C levels"); | |
1150 | assignment(ls, &nv, nvars+1); | |
1151 | } | |
1152 | else { /* assignment -> `=' explist */ | |
1153 | int nexps; | |
1154 | checknext(ls, '='); | |
1155 | nexps = explist(ls, &e); | |
1156 | if (nexps != nvars) { | |
1157 | adjust_assign(ls, nvars, nexps, &e); | |
1158 | if (nexps > nvars) | |
1159 | ls->fs->freereg -= nexps - nvars; /* remove extra values */ | |
1160 | } | |
1161 | else { | |
1162 | luaK_setoneret(ls->fs, &e); /* close last expression */ | |
1163 | luaK_storevar(ls->fs, &lh->v, &e); | |
1164 | return; /* avoid default */ | |
1165 | } | |
1166 | } | |
1167 | init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */ | |
1168 | luaK_storevar(ls->fs, &lh->v, &e); | |
1169 | } | |
1170 | ||
1171 | ||
1172 | static int cond (LexState *ls) { | |
1173 | /* cond -> exp */ | |
1174 | expdesc v; | |
1175 | expr(ls, &v); /* read condition */ | |
1176 | if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */ | |
1177 | luaK_goiftrue(ls->fs, &v); | |
1178 | return v.f; | |
1179 | } | |
1180 | ||
1181 | ||
1182 | static void gotostat (LexState *ls, int pc) { | |
1183 | int line = ls->linenumber; | |
1184 | TString *label; | |
1185 | int g; | |
1186 | if (testnext(ls, TK_GOTO)) | |
1187 | label = str_checkname(ls); | |
1188 | else { | |
1189 | luaX_next(ls); /* skip break */ | |
1190 | label = luaS_new(ls->L, "break"); | |
1191 | } | |
1192 | g = newlabelentry(ls, &ls->dyd->gt, label, line, pc); | |
1193 | findlabel(ls, g); /* close it if label already defined */ | |
1194 | } | |
1195 | ||
1196 | ||
1197 | /* check for repeated labels on the same block */ | |
1198 | static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) { | |
1199 | int i; | |
1200 | for (i = fs->bl->firstlabel; i < ll->n; i++) { | |
1201 | if (luaS_eqstr(label, ll->arr[i].name)) { | |
1202 | const char *msg = luaO_pushfstring(fs->ls->L, | |
1203 | "label " LUA_QS " already defined on line %d", | |
1204 | getstr(label), ll->arr[i].line); | |
1205 | semerror(fs->ls, msg); | |
1206 | } | |
1207 | } | |
1208 | } | |
1209 | ||
1210 | ||
1211 | /* skip no-op statements */ | |
1212 | static void skipnoopstat (LexState *ls) { | |
1213 | while (ls->t.token == ';' || ls->t.token == TK_DBCOLON) | |
1214 | statement(ls); | |
1215 | } | |
1216 | ||
1217 | ||
1218 | static void labelstat (LexState *ls, TString *label, int line) { | |
1219 | /* label -> '::' NAME '::' */ | |
1220 | FuncState *fs = ls->fs; | |
1221 | Labellist *ll = &ls->dyd->label; | |
1222 | int l; /* index of new label being created */ | |
1223 | checkrepeated(fs, ll, label); /* check for repeated labels */ | |
1224 | checknext(ls, TK_DBCOLON); /* skip double colon */ | |
1225 | /* create new entry for this label */ | |
1226 | l = newlabelentry(ls, ll, label, line, fs->pc); | |
1227 | skipnoopstat(ls); /* skip other no-op statements */ | |
1228 | if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */ | |
1229 | /* assume that locals are already out of scope */ | |
1230 | ll->arr[l].nactvar = fs->bl->nactvar; | |
1231 | } | |
1232 | findgotos(ls, &ll->arr[l]); | |
1233 | } | |
1234 | ||
1235 | ||
1236 | static void whilestat (LexState *ls, int line) { | |
1237 | /* whilestat -> WHILE cond DO block END */ | |
1238 | FuncState *fs = ls->fs; | |
1239 | int whileinit; | |
1240 | int condexit; | |
1241 | BlockCnt bl; | |
1242 | luaX_next(ls); /* skip WHILE */ | |
1243 | whileinit = luaK_getlabel(fs); | |
1244 | condexit = cond(ls); | |
1245 | enterblock(fs, &bl, 1); | |
1246 | checknext(ls, TK_DO); | |
1247 | block(ls); | |
1248 | luaK_jumpto(fs, whileinit); | |
1249 | check_match(ls, TK_END, TK_WHILE, line); | |
1250 | leaveblock(fs); | |
1251 | luaK_patchtohere(fs, condexit); /* false conditions finish the loop */ | |
1252 | } | |
1253 | ||
1254 | ||
1255 | static void repeatstat (LexState *ls, int line) { | |
1256 | /* repeatstat -> REPEAT block UNTIL cond */ | |
1257 | int condexit; | |
1258 | FuncState *fs = ls->fs; | |
1259 | int repeat_init = luaK_getlabel(fs); | |
1260 | BlockCnt bl1, bl2; | |
1261 | enterblock(fs, &bl1, 1); /* loop block */ | |
1262 | enterblock(fs, &bl2, 0); /* scope block */ | |
1263 | luaX_next(ls); /* skip REPEAT */ | |
1264 | statlist(ls); | |
1265 | check_match(ls, TK_UNTIL, TK_REPEAT, line); | |
1266 | condexit = cond(ls); /* read condition (inside scope block) */ | |
1267 | if (bl2.upval) /* upvalues? */ | |
1268 | luaK_patchclose(fs, condexit, bl2.nactvar); | |
1269 | leaveblock(fs); /* finish scope */ | |
1270 | luaK_patchlist(fs, condexit, repeat_init); /* close the loop */ | |
1271 | leaveblock(fs); /* finish loop */ | |
1272 | } | |
1273 | ||
1274 | ||
1275 | static int exp1 (LexState *ls) { | |
1276 | expdesc e; | |
1277 | int reg; | |
1278 | expr(ls, &e); | |
1279 | luaK_exp2nextreg(ls->fs, &e); | |
1280 | lua_assert(e.k == VNONRELOC); | |
1281 | reg = e.u.info; | |
1282 | return reg; | |
1283 | } | |
1284 | ||
1285 | ||
1286 | static void forbody (LexState *ls, int base, int line, int nvars, int isnum) { | |
1287 | /* forbody -> DO block */ | |
1288 | BlockCnt bl; | |
1289 | FuncState *fs = ls->fs; | |
1290 | int prep, endfor; | |
1291 | adjustlocalvars(ls, 3); /* control variables */ | |
1292 | checknext(ls, TK_DO); | |
1293 | prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs); | |
1294 | enterblock(fs, &bl, 0); /* scope for declared variables */ | |
1295 | adjustlocalvars(ls, nvars); | |
1296 | luaK_reserveregs(fs, nvars); | |
1297 | block(ls); | |
1298 | leaveblock(fs); /* end of scope for declared variables */ | |
1299 | luaK_patchtohere(fs, prep); | |
1300 | if (isnum) /* numeric for? */ | |
1301 | endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP); | |
1302 | else { /* generic for */ | |
1303 | luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars); | |
1304 | luaK_fixline(fs, line); | |
1305 | endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP); | |
1306 | } | |
1307 | luaK_patchlist(fs, endfor, prep + 1); | |
1308 | luaK_fixline(fs, line); | |
1309 | } | |
1310 | ||
1311 | ||
1312 | static void fornum (LexState *ls, TString *varname, int line) { | |
1313 | /* fornum -> NAME = exp1,exp1[,exp1] forbody */ | |
1314 | FuncState *fs = ls->fs; | |
1315 | int base = fs->freereg; | |
1316 | new_localvarliteral(ls, "(for index)"); | |
1317 | new_localvarliteral(ls, "(for limit)"); | |
1318 | new_localvarliteral(ls, "(for step)"); | |
1319 | new_localvar(ls, varname); | |
1320 | checknext(ls, '='); | |
1321 | exp1(ls); /* initial value */ | |
1322 | checknext(ls, ','); | |
1323 | exp1(ls); /* limit */ | |
1324 | if (testnext(ls, ',')) | |
1325 | exp1(ls); /* optional step */ | |
1326 | else { /* default step = 1 */ | |
1327 | luaK_codek(fs, fs->freereg, luaK_numberK(fs, 1)); | |
1328 | luaK_reserveregs(fs, 1); | |
1329 | } | |
1330 | forbody(ls, base, line, 1, 1); | |
1331 | } | |
1332 | ||
1333 | ||
1334 | static void forlist (LexState *ls, TString *indexname) { | |
1335 | /* forlist -> NAME {,NAME} IN explist forbody */ | |
1336 | FuncState *fs = ls->fs; | |
1337 | expdesc e; | |
1338 | int nvars = 4; /* gen, state, control, plus at least one declared var */ | |
1339 | int line; | |
1340 | int base = fs->freereg; | |
1341 | /* create control variables */ | |
1342 | new_localvarliteral(ls, "(for generator)"); | |
1343 | new_localvarliteral(ls, "(for state)"); | |
1344 | new_localvarliteral(ls, "(for control)"); | |
1345 | /* create declared variables */ | |
1346 | new_localvar(ls, indexname); | |
1347 | while (testnext(ls, ',')) { | |
1348 | new_localvar(ls, str_checkname(ls)); | |
1349 | nvars++; | |
1350 | } | |
1351 | checknext(ls, TK_IN); | |
1352 | line = ls->linenumber; | |
1353 | adjust_assign(ls, 3, explist(ls, &e), &e); | |
1354 | luaK_checkstack(fs, 3); /* extra space to call generator */ | |
1355 | forbody(ls, base, line, nvars - 3, 0); | |
1356 | } | |
1357 | ||
1358 | ||
1359 | static void forstat (LexState *ls, int line) { | |
1360 | /* forstat -> FOR (fornum | forlist) END */ | |
1361 | FuncState *fs = ls->fs; | |
1362 | TString *varname; | |
1363 | BlockCnt bl; | |
1364 | enterblock(fs, &bl, 1); /* scope for loop and control variables */ | |
1365 | luaX_next(ls); /* skip `for' */ | |
1366 | varname = str_checkname(ls); /* first variable name */ | |
1367 | switch (ls->t.token) { | |
1368 | case '=': fornum(ls, varname, line); break; | |
1369 | case ',': case TK_IN: forlist(ls, varname); break; | |
1370 | default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected"); | |
1371 | } | |
1372 | check_match(ls, TK_END, TK_FOR, line); | |
1373 | leaveblock(fs); /* loop scope (`break' jumps to this point) */ | |
1374 | } | |
1375 | ||
1376 | ||
1377 | __attribute__((always_inline)) inline | |
1378 | static void test_then_block (LexState *ls, int *escapelist) { | |
1379 | /* test_then_block -> [IF | ELSEIF] cond THEN block */ | |
1380 | BlockCnt bl; | |
1381 | FuncState *fs = ls->fs; | |
1382 | expdesc v; | |
1383 | int jf; /* instruction to skip 'then' code (if condition is false) */ | |
1384 | luaX_next(ls); /* skip IF or ELSEIF */ | |
1385 | expr(ls, &v); /* read condition */ | |
1386 | checknext(ls, TK_THEN); | |
1387 | if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) { | |
1388 | luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */ | |
1389 | enterblock(fs, &bl, 0); /* must enter block before 'goto' */ | |
1390 | gotostat(ls, v.t); /* handle goto/break */ | |
1391 | skipnoopstat(ls); /* skip other no-op statements */ | |
1392 | if (block_follow(ls, 0)) { /* 'goto' is the entire block? */ | |
1393 | leaveblock(fs); | |
1394 | return; /* and that is it */ | |
1395 | } | |
1396 | else /* must skip over 'then' part if condition is false */ | |
1397 | jf = luaK_jump(fs); | |
1398 | } | |
1399 | else { /* regular case (not goto/break) */ | |
1400 | luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */ | |
1401 | enterblock(fs, &bl, 0); | |
1402 | jf = v.f; | |
1403 | } | |
1404 | statlist(ls); /* `then' part */ | |
1405 | leaveblock(fs); | |
1406 | if (ls->t.token == TK_ELSE || | |
1407 | ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */ | |
1408 | luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */ | |
1409 | luaK_patchtohere(fs, jf); | |
1410 | } | |
1411 | ||
1412 | ||
1413 | static void ifstat (LexState *ls, int line) { | |
1414 | /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */ | |
1415 | FuncState *fs = ls->fs; | |
1416 | int escapelist = NO_JUMP; /* exit list for finished parts */ | |
1417 | test_then_block(ls, &escapelist); /* IF cond THEN block */ | |
1418 | while (ls->t.token == TK_ELSEIF) | |
1419 | test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */ | |
1420 | if (testnext(ls, TK_ELSE)) | |
1421 | block(ls); /* `else' part */ | |
1422 | check_match(ls, TK_END, TK_IF, line); | |
1423 | luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */ | |
1424 | } | |
1425 | ||
1426 | ||
1427 | static void localfunc (LexState *ls) { | |
1428 | expdesc b; | |
1429 | FuncState *fs = ls->fs; | |
1430 | new_localvar(ls, str_checkname(ls)); /* new local variable */ | |
1431 | adjustlocalvars(ls, 1); /* enter its scope */ | |
1432 | body(ls, &b, 0, ls->linenumber); /* function created in next register */ | |
1433 | /* debug information will only see the variable after this point! */ | |
1434 | getlocvar(fs, b.u.info)->startpc = fs->pc; | |
1435 | } | |
1436 | ||
1437 | ||
1438 | static void localstat (LexState *ls) { | |
1439 | /* stat -> LOCAL NAME {`,' NAME} [`=' explist] */ | |
1440 | int nvars = 0; | |
1441 | int nexps; | |
1442 | expdesc e; | |
1443 | do { | |
1444 | new_localvar(ls, str_checkname(ls)); | |
1445 | nvars++; | |
1446 | } while (testnext(ls, ',')); | |
1447 | if (testnext(ls, '=')) | |
1448 | nexps = explist(ls, &e); | |
1449 | else { | |
1450 | e.k = VVOID; | |
1451 | nexps = 0; | |
1452 | } | |
1453 | adjust_assign(ls, nvars, nexps, &e); | |
1454 | adjustlocalvars(ls, nvars); | |
1455 | } | |
1456 | ||
1457 | ||
1458 | static int funcname (LexState *ls, expdesc *v) { | |
1459 | /* funcname -> NAME {fieldsel} [`:' NAME] */ | |
1460 | int ismethod = 0; | |
1461 | singlevar(ls, v); | |
1462 | while (ls->t.token == '.') | |
1463 | fieldsel(ls, v); | |
1464 | if (ls->t.token == ':') { | |
1465 | ismethod = 1; | |
1466 | fieldsel(ls, v); | |
1467 | } | |
1468 | return ismethod; | |
1469 | } | |
1470 | ||
1471 | ||
1472 | static void funcstat (LexState *ls, int line) { | |
1473 | /* funcstat -> FUNCTION funcname body */ | |
1474 | int ismethod; | |
1475 | expdesc v, b; | |
1476 | luaX_next(ls); /* skip FUNCTION */ | |
1477 | ismethod = funcname(ls, &v); | |
1478 | body(ls, &b, ismethod, line); | |
1479 | luaK_storevar(ls->fs, &v, &b); | |
1480 | luaK_fixline(ls->fs, line); /* definition `happens' in the first line */ | |
1481 | } | |
1482 | ||
1483 | ||
1484 | static void exprstat (LexState *ls) { | |
1485 | /* stat -> func | assignment */ | |
1486 | FuncState *fs = ls->fs; | |
1487 | struct LHS_assign v; | |
1488 | suffixedexp(ls, &v.v); | |
1489 | if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */ | |
1490 | v.prev = NULL; | |
1491 | assignment(ls, &v, 1); | |
1492 | } | |
1493 | else { /* stat -> func */ | |
1494 | check_condition(ls, v.v.k == VCALL, "syntax error"); | |
1495 | SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */ | |
1496 | } | |
1497 | } | |
1498 | ||
1499 | ||
1500 | static void retstat (LexState *ls) { | |
1501 | /* stat -> RETURN [explist] [';'] */ | |
1502 | FuncState *fs = ls->fs; | |
1503 | expdesc e; | |
1504 | int first, nret; /* registers with returned values */ | |
1505 | if (block_follow(ls, 1) || ls->t.token == ';') | |
1506 | first = nret = 0; /* return no values */ | |
1507 | else { | |
1508 | nret = explist(ls, &e); /* optional return values */ | |
1509 | if (hasmultret(e.k)) { | |
1510 | luaK_setmultret(fs, &e); | |
1511 | if (e.k == VCALL && nret == 1) { /* tail call? */ | |
1512 | SET_OPCODE(getcode(fs,&e), OP_TAILCALL); | |
1513 | lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar); | |
1514 | } | |
1515 | first = fs->nactvar; | |
1516 | nret = LUA_MULTRET; /* return all values */ | |
1517 | } | |
1518 | else { | |
1519 | if (nret == 1) /* only one single value? */ | |
1520 | first = luaK_exp2anyreg(fs, &e); | |
1521 | else { | |
1522 | luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */ | |
1523 | first = fs->nactvar; /* return all `active' values */ | |
1524 | lua_assert(nret == fs->freereg - first); | |
1525 | } | |
1526 | } | |
1527 | } | |
1528 | luaK_ret(fs, first, nret); | |
cbce5813 | 1529 | (void) testnext(ls, ';'); /* skip optional semicolon */ |
d99a0153 CW |
1530 | } |
1531 | ||
1532 | ||
1533 | static void statement (LexState *ls) { | |
1534 | int line = ls->linenumber; /* may be needed for error messages */ | |
1535 | enterlevel(ls); | |
1536 | switch (ls->t.token) { | |
1537 | case ';': { /* stat -> ';' (empty statement) */ | |
1538 | luaX_next(ls); /* skip ';' */ | |
1539 | break; | |
1540 | } | |
1541 | case TK_IF: { /* stat -> ifstat */ | |
1542 | ifstat(ls, line); | |
1543 | break; | |
1544 | } | |
1545 | case TK_WHILE: { /* stat -> whilestat */ | |
1546 | whilestat(ls, line); | |
1547 | break; | |
1548 | } | |
1549 | case TK_DO: { /* stat -> DO block END */ | |
1550 | luaX_next(ls); /* skip DO */ | |
1551 | block(ls); | |
1552 | check_match(ls, TK_END, TK_DO, line); | |
1553 | break; | |
1554 | } | |
1555 | case TK_FOR: { /* stat -> forstat */ | |
1556 | forstat(ls, line); | |
1557 | break; | |
1558 | } | |
1559 | case TK_REPEAT: { /* stat -> repeatstat */ | |
1560 | repeatstat(ls, line); | |
1561 | break; | |
1562 | } | |
1563 | case TK_FUNCTION: { /* stat -> funcstat */ | |
1564 | funcstat(ls, line); | |
1565 | break; | |
1566 | } | |
1567 | case TK_LOCAL: { /* stat -> localstat */ | |
1568 | luaX_next(ls); /* skip LOCAL */ | |
1569 | if (testnext(ls, TK_FUNCTION)) /* local function? */ | |
1570 | localfunc(ls); | |
1571 | else | |
1572 | localstat(ls); | |
1573 | break; | |
1574 | } | |
1575 | case TK_DBCOLON: { /* stat -> label */ | |
1576 | luaX_next(ls); /* skip double colon */ | |
1577 | labelstat(ls, str_checkname(ls), line); | |
1578 | break; | |
1579 | } | |
1580 | case TK_RETURN: { /* stat -> retstat */ | |
1581 | luaX_next(ls); /* skip RETURN */ | |
1582 | retstat(ls); | |
1583 | break; | |
1584 | } | |
1585 | case TK_BREAK: /* stat -> breakstat */ | |
1586 | case TK_GOTO: { /* stat -> 'goto' NAME */ | |
1587 | gotostat(ls, luaK_jump(ls->fs)); | |
1588 | break; | |
1589 | } | |
1590 | default: { /* stat -> func | assignment */ | |
1591 | exprstat(ls); | |
1592 | break; | |
1593 | } | |
1594 | } | |
1595 | lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg && | |
1596 | ls->fs->freereg >= ls->fs->nactvar); | |
1597 | ls->fs->freereg = ls->fs->nactvar; /* free registers */ | |
1598 | leavelevel(ls); | |
1599 | } | |
1600 | ||
1601 | /* }====================================================================== */ | |
1602 | ||
1603 | ||
1604 | /* | |
1605 | ** compiles the main function, which is a regular vararg function with an | |
1606 | ** upvalue named LUA_ENV | |
1607 | */ | |
1608 | static void mainfunc (LexState *ls, FuncState *fs) { | |
1609 | BlockCnt bl; | |
1610 | expdesc v; | |
1611 | open_func(ls, fs, &bl); | |
1612 | fs->f->is_vararg = 1; /* main function is always vararg */ | |
1613 | init_exp(&v, VLOCAL, 0); /* create and... */ | |
1614 | newupvalue(fs, ls->envn, &v); /* ...set environment upvalue */ | |
1615 | luaX_next(ls); /* read first token */ | |
1616 | statlist(ls); /* parse main body */ | |
1617 | check(ls, TK_EOS); | |
1618 | close_func(ls); | |
1619 | } | |
1620 | ||
1621 | ||
1622 | Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, | |
1623 | Dyndata *dyd, const char *name, int firstchar) { | |
1624 | LexState lexstate; | |
1625 | FuncState funcstate; | |
1626 | Closure *cl = luaF_newLclosure(L, 1); /* create main closure */ | |
1627 | /* anchor closure (to avoid being collected) */ | |
1628 | setclLvalue(L, L->top, cl); | |
1629 | incr_top(L); | |
1630 | funcstate.f = cl->l.p = luaF_newproto(L); | |
1631 | funcstate.f->source = luaS_new(L, name); /* create and anchor TString */ | |
1632 | lexstate.buff = buff; | |
1633 | lexstate.dyd = dyd; | |
1634 | dyd->actvar.n = dyd->gt.n = dyd->label.n = 0; | |
1635 | luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar); | |
1636 | mainfunc(&lexstate, &funcstate); | |
1637 | lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs); | |
1638 | /* all scopes should be correctly finished */ | |
1639 | lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0); | |
1640 | return cl; /* it's on the stack too */ | |
1641 | } |