1 /*
2 ** $Id: lcode.c,v 2.99 2014/12/29 16:49:25 roberto Exp $
3 ** Code generator for Lua
4 ** See Copyright Notice in lua.h
5 */
6
7 #define lcode_c
8 #define LUA_CORE
9
10 #include "lprefix.h"
11
12
13 #include <math.h>
14 #include <stdlib.h>
15
16 #include "lua.h"
17
18 #include "lcode.h"
19 #include "ldebug.h"
20 #include "ldo.h"
21 #include "lgc.h"
22 #include "llex.h"
23 #include "lmem.h"
24 #include "lobject.h"
25 #include "lopcodes.h"
26 #include "lparser.h"
27 #include "lstring.h"
28 #include "ltable.h"
29 #include "lvm.h"
30
31
32 /* Maximum number of registers in a Lua function */
33 #define MAXREGS 250
34
35
36 #define hasjumps(e) ((e)->t != (e)->f)
37
38
tonumeral(expdesc * e,TValue * v)39 static int tonumeral(expdesc *e, TValue *v) {
40 if (e->t != NO_JUMP || e->f != NO_JUMP)
41 return 0; /* not a numeral */
42 switch (e->k) {
43 case VKINT:
44 if (v) setivalue(v, e->u.ival);
45 return 1;
46 case VKFLT:
47 if (v) setfltvalue(v, e->u.nval);
48 return 1;
49 default: return 0;
50 }
51 }
52
53
luaK_nil(FuncState * fs,int from,int n)54 void luaK_nil (FuncState *fs, int from, int n) {
55 Instruction *previous;
56 int l = from + n - 1; /* last register to set nil */
57 if (fs->pc > fs->lasttarget) { /* no jumps to current position? */
58 previous = &fs->f->code[fs->pc-1];
59 if (GET_OPCODE(*previous) == OP_LOADNIL) {
60 int pfrom = GETARG_A(*previous);
61 int pl = pfrom + GETARG_B(*previous);
62 if ((pfrom <= from && from <= pl + 1) ||
63 (from <= pfrom && pfrom <= l + 1)) { /* can connect both? */
64 if (pfrom < from) from = pfrom; /* from = min(from, pfrom) */
65 if (pl > l) l = pl; /* l = max(l, pl) */
66 SETARG_A(*previous, from);
67 SETARG_B(*previous, l - from);
68 return;
69 }
70 } /* else go through */
71 }
72 luaK_codeABC(fs, OP_LOADNIL, from, n - 1, 0); /* else no optimization */
73 }
74
75
luaK_jump(FuncState * fs)76 int luaK_jump (FuncState *fs) {
77 int jpc = fs->jpc; /* save list of jumps to here */
78 int j;
79 fs->jpc = NO_JUMP;
80 j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
81 luaK_concat(fs, &j, jpc); /* keep them on hold */
82 return j;
83 }
84
85
luaK_ret(FuncState * fs,int first,int nret)86 void luaK_ret (FuncState *fs, int first, int nret) {
87 luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);
88 }
89
90
condjump(FuncState * fs,OpCode op,int A,int B,int C)91 static int condjump (FuncState *fs, OpCode op, int A, int B, int C) {
92 luaK_codeABC(fs, op, A, B, C);
93 return luaK_jump(fs);
94 }
95
96
fixjump(FuncState * fs,int pc,int dest)97 static void fixjump (FuncState *fs, int pc, int dest) {
98 Instruction *jmp = &fs->f->code[pc];
99 int offset = dest-(pc+1);
100 lua_assert(dest != NO_JUMP);
101 if (abs(offset) > MAXARG_sBx)
102 luaX_syntaxerror(fs->ls, "control structure too long");
103 SETARG_sBx(*jmp, offset);
104 }
105
106
107 /*
108 ** returns current 'pc' and marks it as a jump target (to avoid wrong
109 ** optimizations with consecutive instructions not in the same basic block).
110 */
luaK_getlabel(FuncState * fs)111 int luaK_getlabel (FuncState *fs) {
112 fs->lasttarget = fs->pc;
113 return fs->pc;
114 }
115
116
getjump(FuncState * fs,int pc)117 static int getjump (FuncState *fs, int pc) {
118 int offset = GETARG_sBx(fs->f->code[pc]);
119 if (offset == NO_JUMP) /* point to itself represents end of list */
120 return NO_JUMP; /* end of list */
121 else
122 return (pc+1)+offset; /* turn offset into absolute position */
123 }
124
125
getjumpcontrol(FuncState * fs,int pc)126 static Instruction *getjumpcontrol (FuncState *fs, int pc) {
127 Instruction *pi = &fs->f->code[pc];
128 if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))
129 return pi-1;
130 else
131 return pi;
132 }
133
134
135 /*
136 ** check whether list has any jump that do not produce a value
137 ** (or produce an inverted value)
138 */
need_value(FuncState * fs,int list)139 static int need_value (FuncState *fs, int list) {
140 for (; list != NO_JUMP; list = getjump(fs, list)) {
141 Instruction i = *getjumpcontrol(fs, list);
142 if (GET_OPCODE(i) != OP_TESTSET) return 1;
143 }
144 return 0; /* not found */
145 }
146
147
patchtestreg(FuncState * fs,int node,int reg)148 static int patchtestreg (FuncState *fs, int node, int reg) {
149 Instruction *i = getjumpcontrol(fs, node);
150 if (GET_OPCODE(*i) != OP_TESTSET)
151 return 0; /* cannot patch other instructions */
152 if (reg != NO_REG && reg != GETARG_B(*i))
153 SETARG_A(*i, reg);
154 else /* no register to put value or register already has the value */
155 *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
156
157 return 1;
158 }
159
160
removevalues(FuncState * fs,int list)161 static void removevalues (FuncState *fs, int list) {
162 for (; list != NO_JUMP; list = getjump(fs, list))
163 patchtestreg(fs, list, NO_REG);
164 }
165
166
patchlistaux(FuncState * fs,int list,int vtarget,int reg,int dtarget)167 static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
168 int dtarget) {
169 while (list != NO_JUMP) {
170 int next = getjump(fs, list);
171 if (patchtestreg(fs, list, reg))
172 fixjump(fs, list, vtarget);
173 else
174 fixjump(fs, list, dtarget); /* jump to default target */
175 list = next;
176 }
177 }
178
179
dischargejpc(FuncState * fs)180 static void dischargejpc (FuncState *fs) {
181 patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
182 fs->jpc = NO_JUMP;
183 }
184
185
luaK_patchlist(FuncState * fs,int list,int target)186 void luaK_patchlist (FuncState *fs, int list, int target) {
187 if (target == fs->pc)
188 luaK_patchtohere(fs, list);
189 else {
190 lua_assert(target < fs->pc);
191 patchlistaux(fs, list, target, NO_REG, target);
192 }
193 }
194
195
luaK_patchclose(FuncState * fs,int list,int level)196 void luaK_patchclose (FuncState *fs, int list, int level) {
197 level++; /* argument is +1 to reserve 0 as non-op */
198 while (list != NO_JUMP) {
199 int next = getjump(fs, list);
200 lua_assert(GET_OPCODE(fs->f->code[list]) == OP_JMP &&
201 (GETARG_A(fs->f->code[list]) == 0 ||
202 GETARG_A(fs->f->code[list]) >= level));
203 SETARG_A(fs->f->code[list], level);
204 list = next;
205 }
206 }
207
208
luaK_patchtohere(FuncState * fs,int list)209 void luaK_patchtohere (FuncState *fs, int list) {
210 luaK_getlabel(fs);
211 luaK_concat(fs, &fs->jpc, list);
212 }
213
214
luaK_concat(FuncState * fs,int * l1,int l2)215 void luaK_concat (FuncState *fs, int *l1, int l2) {
216 if (l2 == NO_JUMP) return;
217 else if (*l1 == NO_JUMP)
218 *l1 = l2;
219 else {
220 int list = *l1;
221 int next;
222 while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */
223 list = next;
224 fixjump(fs, list, l2);
225 }
226 }
227
228
luaK_code(FuncState * fs,Instruction i)229 static int luaK_code (FuncState *fs, Instruction i) {
230 Proto *f = fs->f;
231 dischargejpc(fs); /* 'pc' will change */
232 /* put new instruction in code array */
233 luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction,
234 MAX_INT, "opcodes");
235 f->code[fs->pc] = i;
236 /* save corresponding line information */
237 luaM_growvector(fs->ls->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
238 MAX_INT, "opcodes");
239 f->lineinfo[fs->pc] = fs->ls->lastline;
240 return fs->pc++;
241 }
242
243
luaK_codeABC(FuncState * fs,OpCode o,int a,int b,int c)244 int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
245 lua_assert(getOpMode(o) == iABC);
246 lua_assert(getBMode(o) != OpArgN || b == 0);
247 lua_assert(getCMode(o) != OpArgN || c == 0);
248 lua_assert(a <= MAXARG_A && b <= MAXARG_B && c <= MAXARG_C);
249 return luaK_code(fs, CREATE_ABC(o, a, b, c));
250 }
251
252
luaK_codeABx(FuncState * fs,OpCode o,int a,unsigned int bc)253 int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
254 lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
255 lua_assert(getCMode(o) == OpArgN);
256 lua_assert(a <= MAXARG_A && bc <= MAXARG_Bx);
257 return luaK_code(fs, CREATE_ABx(o, a, bc));
258 }
259
260
codeextraarg(FuncState * fs,int a)261 static int codeextraarg (FuncState *fs, int a) {
262 lua_assert(a <= MAXARG_Ax);
263 return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a));
264 }
265
266
luaK_codek(FuncState * fs,int reg,int k)267 int luaK_codek (FuncState *fs, int reg, int k) {
268 if (k <= MAXARG_Bx)
269 return luaK_codeABx(fs, OP_LOADK, reg, k);
270 else {
271 int p = luaK_codeABx(fs, OP_LOADKX, reg, 0);
272 codeextraarg(fs, k);
273 return p;
274 }
275 }
276
277
luaK_checkstack(FuncState * fs,int n)278 void luaK_checkstack (FuncState *fs, int n) {
279 int newstack = fs->freereg + n;
280 if (newstack > fs->f->maxstacksize) {
281 if (newstack >= MAXREGS)
282 luaX_syntaxerror(fs->ls, "function or expression too complex");
283 fs->f->maxstacksize = cast_byte(newstack);
284 }
285 }
286
287
luaK_reserveregs(FuncState * fs,int n)288 void luaK_reserveregs (FuncState *fs, int n) {
289 luaK_checkstack(fs, n);
290 fs->freereg += n;
291 }
292
293
freereg(FuncState * fs,int reg)294 static void freereg (FuncState *fs, int reg) {
295 if (!ISK(reg) && reg >= fs->nactvar) {
296 fs->freereg--;
297 lua_assert(reg == fs->freereg);
298 }
299 }
300
301
freeexp(FuncState * fs,expdesc * e)302 static void freeexp (FuncState *fs, expdesc *e) {
303 if (e->k == VNONRELOC)
304 freereg(fs, e->u.info);
305 }
306
307
308 /*
309 ** Use scanner's table to cache position of constants in constant list
310 ** and try to reuse constants
311 */
addk(FuncState * fs,TValue * key,TValue * v)312 static int addk (FuncState *fs, TValue *key, TValue *v) {
313 lua_State *L = fs->ls->L;
314 Proto *f = fs->f;
315 TValue *idx = luaH_set(L, fs->ls->h, key); /* index scanner table */
316 int k, oldsize;
317 if (ttisinteger(idx)) { /* is there an index there? */
318 k = cast_int(ivalue(idx));
319 /* correct value? (warning: must distinguish floats from integers!) */
320 if (k < fs->nk && ttype(&f->k[k]) == ttype(v) &&
321 luaV_rawequalobj(&f->k[k], v))
322 return k; /* reuse index */
323 }
324 /* constant not found; create a new entry */
325 oldsize = f->sizek;
326 k = fs->nk;
327 /* numerical value does not need GC barrier;
328 table has no metatable, so it does not need to invalidate cache */
329 setivalue(idx, k);
330 luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants");
331 while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
332 setobj(L, &f->k[k], v);
333 fs->nk++;
334 luaC_barrier(L, f, v);
335 return k;
336 }
337
338
luaK_stringK(FuncState * fs,TString * s)339 int luaK_stringK (FuncState *fs, TString *s) {
340 TValue o;
341 setsvalue(fs->ls->L, &o, s);
342 return addk(fs, &o, &o);
343 }
344
345
346 /*
347 ** Integers use userdata as keys to avoid collision with floats with same
348 ** value; conversion to 'void*' used only for hashing, no "precision"
349 ** problems
350 */
luaK_intK(FuncState * fs,lua_Integer n)351 int luaK_intK (FuncState *fs, lua_Integer n) {
352 TValue k, o;
353 setpvalue(&k, cast(void*, cast(size_t, n)));
354 setivalue(&o, n);
355 return addk(fs, &k, &o);
356 }
357
358
luaK_numberK(FuncState * fs,lua_Number r)359 static int luaK_numberK (FuncState *fs, lua_Number r) {
360 TValue o;
361 setfltvalue(&o, r);
362 return addk(fs, &o, &o);
363 }
364
365
boolK(FuncState * fs,int b)366 static int boolK (FuncState *fs, int b) {
367 TValue o;
368 setbvalue(&o, b);
369 return addk(fs, &o, &o);
370 }
371
372
nilK(FuncState * fs)373 static int nilK (FuncState *fs) {
374 TValue k, v;
375 setnilvalue(&v);
376 /* cannot use nil as key; instead use table itself to represent nil */
377 sethvalue(fs->ls->L, &k, fs->ls->h);
378 return addk(fs, &k, &v);
379 }
380
381
luaK_setreturns(FuncState * fs,expdesc * e,int nresults)382 void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
383 if (e->k == VCALL) { /* expression is an open function call? */
384 SETARG_C(getcode(fs, e), nresults+1);
385 }
386 else if (e->k == VVARARG) {
387 SETARG_B(getcode(fs, e), nresults+1);
388 SETARG_A(getcode(fs, e), fs->freereg);
389 luaK_reserveregs(fs, 1);
390 }
391 }
392
393
luaK_setoneret(FuncState * fs,expdesc * e)394 void luaK_setoneret (FuncState *fs, expdesc *e) {
395 if (e->k == VCALL) { /* expression is an open function call? */
396 e->k = VNONRELOC;
397 e->u.info = GETARG_A(getcode(fs, e));
398 }
399 else if (e->k == VVARARG) {
400 SETARG_B(getcode(fs, e), 2);
401 e->k = VRELOCABLE; /* can relocate its simple result */
402 }
403 }
404
405
luaK_dischargevars(FuncState * fs,expdesc * e)406 void luaK_dischargevars (FuncState *fs, expdesc *e) {
407 switch (e->k) {
408 case VLOCAL: {
409 e->k = VNONRELOC;
410 break;
411 }
412 case VUPVAL: {
413 e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0);
414 e->k = VRELOCABLE;
415 break;
416 }
417 case VINDEXED: {
418 OpCode op = OP_GETTABUP; /* assume 't' is in an upvalue */
419 freereg(fs, e->u.ind.idx);
420 if (e->u.ind.vt == VLOCAL) { /* 't' is in a register? */
421 freereg(fs, e->u.ind.t);
422 op = OP_GETTABLE;
423 }
424 e->u.info = luaK_codeABC(fs, op, 0, e->u.ind.t, e->u.ind.idx);
425 e->k = VRELOCABLE;
426 break;
427 }
428 case VVARARG:
429 case VCALL: {
430 luaK_setoneret(fs, e);
431 break;
432 }
433 default: break; /* there is one value available (somewhere) */
434 }
435 }
436
437
code_label(FuncState * fs,int A,int b,int jump)438 static int code_label (FuncState *fs, int A, int b, int jump) {
439 luaK_getlabel(fs); /* those instructions may be jump targets */
440 return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
441 }
442
443
discharge2reg(FuncState * fs,expdesc * e,int reg)444 static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
445 luaK_dischargevars(fs, e);
446 switch (e->k) {
447 case VNIL: {
448 luaK_nil(fs, reg, 1);
449 break;
450 }
451 case VFALSE: case VTRUE: {
452 luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
453 break;
454 }
455 case VK: {
456 luaK_codek(fs, reg, e->u.info);
457 break;
458 }
459 case VKFLT: {
460 luaK_codek(fs, reg, luaK_numberK(fs, e->u.nval));
461 break;
462 }
463 case VKINT: {
464 luaK_codek(fs, reg, luaK_intK(fs, e->u.ival));
465 break;
466 }
467 case VRELOCABLE: {
468 Instruction *pc = &getcode(fs, e);
469 SETARG_A(*pc, reg);
470 break;
471 }
472 case VNONRELOC: {
473 if (reg != e->u.info)
474 luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0);
475 break;
476 }
477 default: {
478 lua_assert(e->k == VVOID || e->k == VJMP);
479 return; /* nothing to do... */
480 }
481 }
482 e->u.info = reg;
483 e->k = VNONRELOC;
484 }
485
486
discharge2anyreg(FuncState * fs,expdesc * e)487 static void discharge2anyreg (FuncState *fs, expdesc *e) {
488 if (e->k != VNONRELOC) {
489 luaK_reserveregs(fs, 1);
490 discharge2reg(fs, e, fs->freereg-1);
491 }
492 }
493
494
exp2reg(FuncState * fs,expdesc * e,int reg)495 static void exp2reg (FuncState *fs, expdesc *e, int reg) {
496 discharge2reg(fs, e, reg);
497 if (e->k == VJMP)
498 luaK_concat(fs, &e->t, e->u.info); /* put this jump in 't' list */
499 if (hasjumps(e)) {
500 int final; /* position after whole expression */
501 int p_f = NO_JUMP; /* position of an eventual LOAD false */
502 int p_t = NO_JUMP; /* position of an eventual LOAD true */
503 if (need_value(fs, e->t) || need_value(fs, e->f)) {
504 int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
505 p_f = code_label(fs, reg, 0, 1);
506 p_t = code_label(fs, reg, 1, 0);
507 luaK_patchtohere(fs, fj);
508 }
509 final = luaK_getlabel(fs);
510 patchlistaux(fs, e->f, final, reg, p_f);
511 patchlistaux(fs, e->t, final, reg, p_t);
512 }
513 e->f = e->t = NO_JUMP;
514 e->u.info = reg;
515 e->k = VNONRELOC;
516 }
517
518
luaK_exp2nextreg(FuncState * fs,expdesc * e)519 void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
520 luaK_dischargevars(fs, e);
521 freeexp(fs, e);
522 luaK_reserveregs(fs, 1);
523 exp2reg(fs, e, fs->freereg - 1);
524 }
525
526
luaK_exp2anyreg(FuncState * fs,expdesc * e)527 int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
528 luaK_dischargevars(fs, e);
529 if (e->k == VNONRELOC) {
530 if (!hasjumps(e)) return e->u.info; /* exp is already in a register */
531 if (e->u.info >= fs->nactvar) { /* reg. is not a local? */
532 exp2reg(fs, e, e->u.info); /* put value on it */
533 return e->u.info;
534 }
535 }
536 luaK_exp2nextreg(fs, e); /* default */
537 return e->u.info;
538 }
539
540
luaK_exp2anyregup(FuncState * fs,expdesc * e)541 void luaK_exp2anyregup (FuncState *fs, expdesc *e) {
542 if (e->k != VUPVAL || hasjumps(e))
543 luaK_exp2anyreg(fs, e);
544 }
545
546
luaK_exp2val(FuncState * fs,expdesc * e)547 void luaK_exp2val (FuncState *fs, expdesc *e) {
548 if (hasjumps(e))
549 luaK_exp2anyreg(fs, e);
550 else
551 luaK_dischargevars(fs, e);
552 }
553
554
luaK_exp2RK(FuncState * fs,expdesc * e)555 int luaK_exp2RK (FuncState *fs, expdesc *e) {
556 luaK_exp2val(fs, e);
557 switch (e->k) {
558 case VTRUE:
559 case VFALSE:
560 case VNIL: {
561 if (fs->nk <= MAXINDEXRK) { /* constant fits in RK operand? */
562 e->u.info = (e->k == VNIL) ? nilK(fs) : boolK(fs, (e->k == VTRUE));
563 e->k = VK;
564 return RKASK(e->u.info);
565 }
566 else break;
567 }
568 case VKINT: {
569 e->u.info = luaK_intK(fs, e->u.ival);
570 e->k = VK;
571 goto vk;
572 }
573 case VKFLT: {
574 e->u.info = luaK_numberK(fs, e->u.nval);
575 e->k = VK;
576 /* go through */
577 }
578 case VK: {
579 vk:
580 if (e->u.info <= MAXINDEXRK) /* constant fits in 'argC'? */
581 return RKASK(e->u.info);
582 else break;
583 }
584 default: break;
585 }
586 /* not a constant in the right range: put it in a register */
587 return luaK_exp2anyreg(fs, e);
588 }
589
590
luaK_storevar(FuncState * fs,expdesc * var,expdesc * ex)591 void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
592 switch (var->k) {
593 case VLOCAL: {
594 freeexp(fs, ex);
595 exp2reg(fs, ex, var->u.info);
596 return;
597 }
598 case VUPVAL: {
599 int e = luaK_exp2anyreg(fs, ex);
600 luaK_codeABC(fs, OP_SETUPVAL, e, var->u.info, 0);
601 break;
602 }
603 case VINDEXED: {
604 OpCode op = (var->u.ind.vt == VLOCAL) ? OP_SETTABLE : OP_SETTABUP;
605 int e = luaK_exp2RK(fs, ex);
606 luaK_codeABC(fs, op, var->u.ind.t, var->u.ind.idx, e);
607 break;
608 }
609 default: {
610 lua_assert(0); /* invalid var kind to store */
611 break;
612 }
613 }
614 freeexp(fs, ex);
615 }
616
617
luaK_self(FuncState * fs,expdesc * e,expdesc * key)618 void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
619 int ereg;
620 luaK_exp2anyreg(fs, e);
621 ereg = e->u.info; /* register where 'e' was placed */
622 freeexp(fs, e);
623 e->u.info = fs->freereg; /* base register for op_self */
624 e->k = VNONRELOC;
625 luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */
626 luaK_codeABC(fs, OP_SELF, e->u.info, ereg, luaK_exp2RK(fs, key));
627 freeexp(fs, key);
628 }
629
630
invertjump(FuncState * fs,expdesc * e)631 static void invertjump (FuncState *fs, expdesc *e) {
632 Instruction *pc = getjumpcontrol(fs, e->u.info);
633 lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
634 GET_OPCODE(*pc) != OP_TEST);
635 SETARG_A(*pc, !(GETARG_A(*pc)));
636 }
637
638
jumponcond(FuncState * fs,expdesc * e,int cond)639 static int jumponcond (FuncState *fs, expdesc *e, int cond) {
640 if (e->k == VRELOCABLE) {
641 Instruction ie = getcode(fs, e);
642 if (GET_OPCODE(ie) == OP_NOT) {
643 fs->pc--; /* remove previous OP_NOT */
644 return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
645 }
646 /* else go through */
647 }
648 discharge2anyreg(fs, e);
649 freeexp(fs, e);
650 return condjump(fs, OP_TESTSET, NO_REG, e->u.info, cond);
651 }
652
653
luaK_goiftrue(FuncState * fs,expdesc * e)654 void luaK_goiftrue (FuncState *fs, expdesc *e) {
655 int pc; /* pc of last jump */
656 luaK_dischargevars(fs, e);
657 switch (e->k) {
658 case VJMP: {
659 invertjump(fs, e);
660 pc = e->u.info;
661 break;
662 }
663 case VK: case VKFLT: case VKINT: case VTRUE: {
664 pc = NO_JUMP; /* always true; do nothing */
665 break;
666 }
667 default: {
668 pc = jumponcond(fs, e, 0);
669 break;
670 }
671 }
672 luaK_concat(fs, &e->f, pc); /* insert last jump in 'f' list */
673 luaK_patchtohere(fs, e->t);
674 e->t = NO_JUMP;
675 }
676
677
luaK_goiffalse(FuncState * fs,expdesc * e)678 void luaK_goiffalse (FuncState *fs, expdesc *e) {
679 int pc; /* pc of last jump */
680 luaK_dischargevars(fs, e);
681 switch (e->k) {
682 case VJMP: {
683 pc = e->u.info;
684 break;
685 }
686 case VNIL: case VFALSE: {
687 pc = NO_JUMP; /* always false; do nothing */
688 break;
689 }
690 default: {
691 pc = jumponcond(fs, e, 1);
692 break;
693 }
694 }
695 luaK_concat(fs, &e->t, pc); /* insert last jump in 't' list */
696 luaK_patchtohere(fs, e->f);
697 e->f = NO_JUMP;
698 }
699
700
codenot(FuncState * fs,expdesc * e)701 static void codenot (FuncState *fs, expdesc *e) {
702 luaK_dischargevars(fs, e);
703 switch (e->k) {
704 case VNIL: case VFALSE: {
705 e->k = VTRUE;
706 break;
707 }
708 case VK: case VKFLT: case VKINT: case VTRUE: {
709 e->k = VFALSE;
710 break;
711 }
712 case VJMP: {
713 invertjump(fs, e);
714 break;
715 }
716 case VRELOCABLE:
717 case VNONRELOC: {
718 discharge2anyreg(fs, e);
719 freeexp(fs, e);
720 e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0);
721 e->k = VRELOCABLE;
722 break;
723 }
724 default: {
725 lua_assert(0); /* cannot happen */
726 break;
727 }
728 }
729 /* interchange true and false lists */
730 { int temp = e->f; e->f = e->t; e->t = temp; }
731 removevalues(fs, e->f);
732 removevalues(fs, e->t);
733 }
734
735
luaK_indexed(FuncState * fs,expdesc * t,expdesc * k)736 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
737 lua_assert(!hasjumps(t));
738 t->u.ind.t = t->u.info;
739 t->u.ind.idx = luaK_exp2RK(fs, k);
740 t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL
741 : check_exp(vkisinreg(t->k), VLOCAL);
742 t->k = VINDEXED;
743 }
744
745
746 /*
747 ** return false if folding can raise an error
748 */
validop(int op,TValue * v1,TValue * v2)749 static int validop (int op, TValue *v1, TValue *v2) {
750 switch (op) {
751 case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR:
752 case LUA_OPSHL: case LUA_OPSHR: case LUA_OPBNOT: { /* conversion errors */
753 lua_Integer i;
754 return (tointeger(v1, &i) && tointeger(v2, &i));
755 }
756 case LUA_OPDIV: case LUA_OPIDIV: case LUA_OPMOD: /* division by 0 */
757 return (nvalue(v2) != 0);
758 default: return 1; /* everything else is valid */
759 }
760 }
761
762
763 /*
764 ** Try to "constant-fold" an operation; return 1 iff successful
765 */
constfolding(FuncState * fs,int op,expdesc * e1,expdesc * e2)766 static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) {
767 TValue v1, v2, res;
768 if (!tonumeral(e1, &v1) || !tonumeral(e2, &v2) || !validop(op, &v1, &v2))
769 return 0; /* non-numeric operands or not safe to fold */
770 luaO_arith(fs->ls->L, op, &v1, &v2, &res); /* does operation */
771 if (ttisinteger(&res)) {
772 e1->k = VKINT;
773 e1->u.ival = ivalue(&res);
774 }
775 else { /* folds neither NaN nor 0.0 (to avoid collapsing with -0.0) */
776 lua_Number n = fltvalue(&res);
777 if (luai_numisnan(n) || n == 0)
778 return 0;
779 e1->k = VKFLT;
780 e1->u.nval = n;
781 }
782 return 1;
783 }
784
785
786 /*
787 ** Code for binary and unary expressions that "produce values"
788 ** (arithmetic operations, bitwise operations, concat, length). First
789 ** try to do constant folding (only for numeric [arithmetic and
790 ** bitwise] operations, which is what 'lua_arith' accepts).
791 ** Expression to produce final result will be encoded in 'e1'.
792 */
codeexpval(FuncState * fs,OpCode op,expdesc * e1,expdesc * e2,int line)793 static void codeexpval (FuncState *fs, OpCode op,
794 expdesc *e1, expdesc *e2, int line) {
795 lua_assert(op >= OP_ADD);
796 if (op <= OP_BNOT && constfolding(fs, op - OP_ADD + LUA_OPADD, e1, e2))
797 return; /* result has been folded */
798 else {
799 int o1, o2;
800 /* move operands to registers (if needed) */
801 if (op == OP_UNM || op == OP_BNOT || op == OP_LEN) { /* unary op? */
802 o2 = 0; /* no second expression */
803 o1 = luaK_exp2anyreg(fs, e1); /* cannot operate on constants */
804 }
805 else { /* regular case (binary operators) */
806 o2 = luaK_exp2RK(fs, e2); /* both operands are "RK" */
807 o1 = luaK_exp2RK(fs, e1);
808 }
809 if (o1 > o2) { /* free registers in proper order */
810 freeexp(fs, e1);
811 freeexp(fs, e2);
812 }
813 else {
814 freeexp(fs, e2);
815 freeexp(fs, e1);
816 }
817 e1->u.info = luaK_codeABC(fs, op, 0, o1, o2); /* generate opcode */
818 e1->k = VRELOCABLE; /* all those operations are relocable */
819 luaK_fixline(fs, line);
820 }
821 }
822
823
codecomp(FuncState * fs,OpCode op,int cond,expdesc * e1,expdesc * e2)824 static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,
825 expdesc *e2) {
826 int o1 = luaK_exp2RK(fs, e1);
827 int o2 = luaK_exp2RK(fs, e2);
828 freeexp(fs, e2);
829 freeexp(fs, e1);
830 if (cond == 0 && op != OP_EQ) {
831 int temp; /* exchange args to replace by '<' or '<=' */
832 temp = o1; o1 = o2; o2 = temp; /* o1 <==> o2 */
833 cond = 1;
834 }
835 e1->u.info = condjump(fs, op, cond, o1, o2);
836 e1->k = VJMP;
837 }
838
839
luaK_prefix(FuncState * fs,UnOpr op,expdesc * e,int line)840 void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) {
841 expdesc e2;
842 e2.t = e2.f = NO_JUMP; e2.k = VKINT; e2.u.ival = 0;
843 switch (op) {
844 case OPR_MINUS: case OPR_BNOT: case OPR_LEN: {
845 codeexpval(fs, cast(OpCode, (op - OPR_MINUS) + OP_UNM), e, &e2, line);
846 break;
847 }
848 case OPR_NOT: codenot(fs, e); break;
849 default: lua_assert(0);
850 }
851 }
852
853
luaK_infix(FuncState * fs,BinOpr op,expdesc * v)854 void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
855 switch (op) {
856 case OPR_AND: {
857 luaK_goiftrue(fs, v);
858 break;
859 }
860 case OPR_OR: {
861 luaK_goiffalse(fs, v);
862 break;
863 }
864 case OPR_CONCAT: {
865 luaK_exp2nextreg(fs, v); /* operand must be on the 'stack' */
866 break;
867 }
868 case OPR_ADD: case OPR_SUB:
869 case OPR_MUL: case OPR_DIV: case OPR_IDIV:
870 case OPR_MOD: case OPR_POW:
871 case OPR_BAND: case OPR_BOR: case OPR_BXOR:
872 case OPR_SHL: case OPR_SHR: {
873 if (!tonumeral(v, NULL)) luaK_exp2RK(fs, v);
874 break;
875 }
876 default: {
877 luaK_exp2RK(fs, v);
878 break;
879 }
880 }
881 }
882
883
luaK_posfix(FuncState * fs,BinOpr op,expdesc * e1,expdesc * e2,int line)884 void luaK_posfix (FuncState *fs, BinOpr op,
885 expdesc *e1, expdesc *e2, int line) {
886 switch (op) {
887 case OPR_AND: {
888 lua_assert(e1->t == NO_JUMP); /* list must be closed */
889 luaK_dischargevars(fs, e2);
890 luaK_concat(fs, &e2->f, e1->f);
891 *e1 = *e2;
892 break;
893 }
894 case OPR_OR: {
895 lua_assert(e1->f == NO_JUMP); /* list must be closed */
896 luaK_dischargevars(fs, e2);
897 luaK_concat(fs, &e2->t, e1->t);
898 *e1 = *e2;
899 break;
900 }
901 case OPR_CONCAT: {
902 luaK_exp2val(fs, e2);
903 if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
904 lua_assert(e1->u.info == GETARG_B(getcode(fs, e2))-1);
905 freeexp(fs, e1);
906 SETARG_B(getcode(fs, e2), e1->u.info);
907 e1->k = VRELOCABLE; e1->u.info = e2->u.info;
908 }
909 else {
910 luaK_exp2nextreg(fs, e2); /* operand must be on the 'stack' */
911 codeexpval(fs, OP_CONCAT, e1, e2, line);
912 }
913 break;
914 }
915 case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:
916 case OPR_IDIV: case OPR_MOD: case OPR_POW:
917 case OPR_BAND: case OPR_BOR: case OPR_BXOR:
918 case OPR_SHL: case OPR_SHR: {
919 codeexpval(fs, cast(OpCode, (op - OPR_ADD) + OP_ADD), e1, e2, line);
920 break;
921 }
922 case OPR_EQ: case OPR_LT: case OPR_LE: {
923 codecomp(fs, cast(OpCode, op - OPR_EQ + OP_EQ), 1, e1, e2);
924 break;
925 }
926 case OPR_NE: case OPR_GT: case OPR_GE: {
927 codecomp(fs, cast(OpCode, op - OPR_NE + OP_EQ), 0, e1, e2);
928 break;
929 }
930 default: lua_assert(0);
931 }
932 }
933
934
luaK_fixline(FuncState * fs,int line)935 void luaK_fixline (FuncState *fs, int line) {
936 fs->f->lineinfo[fs->pc - 1] = line;
937 }
938
939
luaK_setlist(FuncState * fs,int base,int nelems,int tostore)940 void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
941 int c = (nelems - 1)/LFIELDS_PER_FLUSH + 1;
942 int b = (tostore == LUA_MULTRET) ? 0 : tostore;
943 lua_assert(tostore != 0);
944 if (c <= MAXARG_C)
945 luaK_codeABC(fs, OP_SETLIST, base, b, c);
946 else if (c <= MAXARG_Ax) {
947 luaK_codeABC(fs, OP_SETLIST, base, b, 0);
948 codeextraarg(fs, c);
949 }
950 else
951 luaX_syntaxerror(fs->ls, "constructor too long");
952 fs->freereg = base + 1; /* free registers with list values */
953 }
954
955