2 ** $Id: lcode.c,v 2.25.1.3 2007/12/28 15:32:23 roberto Exp $
3 ** Code generator for Lua
4 ** See Copyright Notice in lua.h
27 #define hasjumps(e) ((e)->t != (e)->f)
30 static int isnumeral(expdesc *e) {
31 return (e->k == VKNUM && e->t == NO_JUMP && e->f == NO_JUMP);
35 void luaK_nil (FuncState *fs, int from, int n) {
36 Instruction *previous;
37 if (fs->pc > fs->lasttarget) { /* no jumps to current position? */
38 if (fs->pc == 0) { /* function start? */
39 if (from >= fs->nactvar)
40 return; /* positions are already clean */
43 previous = &fs->f->code[fs->pc-1];
44 if (GET_OPCODE(*previous) == OP_LOADNIL) {
45 int pfrom = GETARG_A(*previous);
46 int pto = GETARG_B(*previous);
47 if (pfrom <= from && from <= pto+1) { /* can connect both? */
49 SETARG_B(*previous, from+n-1);
55 luaK_codeABC(fs, OP_LOADNIL, from, from+n-1, 0); /* else no optimization */
59 int luaK_jump (FuncState *fs) {
60 int jpc = fs->jpc; /* save list of jumps to here */
63 j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
64 luaK_concat(fs, &j, jpc); /* keep them on hold */
69 void luaK_ret (FuncState *fs, int first, int nret) {
70 luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);
74 static int condjump (FuncState *fs, OpCode op, int A, int B, int C) {
75 luaK_codeABC(fs, op, A, B, C);
80 static void fixjump (FuncState *fs, int pc, int dest) {
81 Instruction *jmp = &fs->f->code[pc];
82 int offset = dest-(pc+1);
83 lua_assert(dest != NO_JUMP);
84 if (abs(offset) > MAXARG_sBx)
85 luaX_syntaxerror(fs->ls, "control structure too long");
86 SETARG_sBx(*jmp, offset);
91 ** returns current `pc' and marks it as a jump target (to avoid wrong
92 ** optimizations with consecutive instructions not in the same basic block).
94 int luaK_getlabel (FuncState *fs) {
95 fs->lasttarget = fs->pc;
100 static int getjump (FuncState *fs, int pc) {
101 int offset = GETARG_sBx(fs->f->code[pc]);
102 if (offset == NO_JUMP) /* point to itself represents end of list */
103 return NO_JUMP; /* end of list */
105 return (pc+1)+offset; /* turn offset into absolute position */
109 static Instruction *getjumpcontrol (FuncState *fs, int pc) {
110 Instruction *pi = &fs->f->code[pc];
111 if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))
119 ** check whether list has any jump that do not produce a value
120 ** (or produce an inverted value)
122 static int need_value (FuncState *fs, int list) {
123 for (; list != NO_JUMP; list = getjump(fs, list)) {
124 Instruction i = *getjumpcontrol(fs, list);
125 if (GET_OPCODE(i) != OP_TESTSET) return 1;
127 return 0; /* not found */
131 static int patchtestreg (FuncState *fs, int node, int reg) {
132 Instruction *i = getjumpcontrol(fs, node);
133 if (GET_OPCODE(*i) != OP_TESTSET)
134 return 0; /* cannot patch other instructions */
135 if (reg != NO_REG && reg != GETARG_B(*i))
137 else /* no register to put value or register already has the value */
138 *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
144 static void removevalues (FuncState *fs, int list) {
145 for (; list != NO_JUMP; list = getjump(fs, list))
146 patchtestreg(fs, list, NO_REG);
150 static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
152 while (list != NO_JUMP) {
153 int next = getjump(fs, list);
154 if (patchtestreg(fs, list, reg))
155 fixjump(fs, list, vtarget);
157 fixjump(fs, list, dtarget); /* jump to default target */
163 static void dischargejpc (FuncState *fs) {
164 patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
169 void luaK_patchlist (FuncState *fs, int list, int target) {
170 if (target == fs->pc)
171 luaK_patchtohere(fs, list);
173 lua_assert(target < fs->pc);
174 patchlistaux(fs, list, target, NO_REG, target);
179 void luaK_patchtohere (FuncState *fs, int list) {
181 luaK_concat(fs, &fs->jpc, list);
185 void luaK_concat (FuncState *fs, int *l1, int l2) {
186 if (l2 == NO_JUMP) return;
187 else if (*l1 == NO_JUMP)
192 while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */
194 fixjump(fs, list, l2);
199 void luaK_checkstack (FuncState *fs, int n) {
200 int newstack = fs->freereg + n;
201 if (newstack > fs->f->maxstacksize) {
202 if (newstack >= MAXSTACK)
203 luaX_syntaxerror(fs->ls, "function or expression too complex");
204 fs->f->maxstacksize = cast_byte(newstack);
209 void luaK_reserveregs (FuncState *fs, int n) {
210 luaK_checkstack(fs, n);
215 static void freereg (FuncState *fs, int reg) {
216 if (!ISK(reg) && reg >= fs->nactvar) {
218 lua_assert(reg == fs->freereg);
223 static void freeexp (FuncState *fs, expdesc *e) {
224 if (e->k == VNONRELOC)
225 freereg(fs, e->u.s.info);
229 static int addk (FuncState *fs, TValue *k, TValue *v) {
230 lua_State *L = fs->L;
231 TValue *idx = luaH_set(L, fs->h, k);
233 int oldsize = f->sizek;
234 if (ttisnumber(idx)) {
235 lua_assert(luaO_rawequalObj(&fs->f->k[cast_int(nvalue(idx))], v));
236 return cast_int(nvalue(idx));
238 else { /* constant not found; create a new entry */
239 setnvalue(idx, cast_num(fs->nk));
240 luaM_growvector(L, f->k, fs->nk, f->sizek, TValue,
241 MAXARG_Bx, "constant table overflow");
242 while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
243 setobj(L, &f->k[fs->nk], v);
244 luaC_barrier(L, f, v);
250 int luaK_stringK (FuncState *fs, TString *s) {
252 setsvalue(fs->L, &o, s);
253 return addk(fs, &o, &o);
257 int luaK_numberK (FuncState *fs, lua_Number r) {
260 return addk(fs, &o, &o);
264 static int boolK (FuncState *fs, int b) {
267 return addk(fs, &o, &o);
271 static int nilK (FuncState *fs) {
274 /* cannot use nil as key; instead use table itself to represent nil */
275 sethvalue(fs->L, &k, fs->h);
276 return addk(fs, &k, &v);
280 void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
281 if (e->k == VCALL) { /* expression is an open function call? */
282 SETARG_C(getcode(fs, e), nresults+1);
284 else if (e->k == VVARARG) {
285 SETARG_B(getcode(fs, e), nresults+1);
286 SETARG_A(getcode(fs, e), fs->freereg);
287 luaK_reserveregs(fs, 1);
292 void luaK_setoneret (FuncState *fs, expdesc *e) {
293 if (e->k == VCALL) { /* expression is an open function call? */
295 e->u.s.info = GETARG_A(getcode(fs, e));
297 else if (e->k == VVARARG) {
298 SETARG_B(getcode(fs, e), 2);
299 e->k = VRELOCABLE; /* can relocate its simple result */
304 void luaK_dischargevars (FuncState *fs, expdesc *e) {
311 e->u.s.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.s.info, 0);
316 e->u.s.info = luaK_codeABx(fs, OP_GETGLOBAL, 0, e->u.s.info);
321 freereg(fs, e->u.s.aux);
322 freereg(fs, e->u.s.info);
323 e->u.s.info = luaK_codeABC(fs, OP_GETTABLE, 0, e->u.s.info, e->u.s.aux);
329 luaK_setoneret(fs, e);
332 default: break; /* there is one value available (somewhere) */
337 static int code_label (FuncState *fs, int A, int b, int jump) {
338 luaK_getlabel(fs); /* those instructions may be jump targets */
339 return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
343 static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
344 luaK_dischargevars(fs, e);
347 luaK_nil(fs, reg, 1);
350 case VFALSE: case VTRUE: {
351 luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
355 luaK_codeABx(fs, OP_LOADK, reg, e->u.s.info);
359 luaK_codeABx(fs, OP_LOADK, reg, luaK_numberK(fs, e->u.nval));
363 Instruction *pc = &getcode(fs, e);
368 if (reg != e->u.s.info)
369 luaK_codeABC(fs, OP_MOVE, reg, e->u.s.info, 0);
373 lua_assert(e->k == VVOID || e->k == VJMP);
374 return; /* nothing to do... */
382 static void discharge2anyreg (FuncState *fs, expdesc *e) {
383 if (e->k != VNONRELOC) {
384 luaK_reserveregs(fs, 1);
385 discharge2reg(fs, e, fs->freereg-1);
390 static void exp2reg (FuncState *fs, expdesc *e, int reg) {
391 discharge2reg(fs, e, reg);
393 luaK_concat(fs, &e->t, e->u.s.info); /* put this jump in `t' list */
395 int final; /* position after whole expression */
396 int p_f = NO_JUMP; /* position of an eventual LOAD false */
397 int p_t = NO_JUMP; /* position of an eventual LOAD true */
398 if (need_value(fs, e->t) || need_value(fs, e->f)) {
399 int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
400 p_f = code_label(fs, reg, 0, 1);
401 p_t = code_label(fs, reg, 1, 0);
402 luaK_patchtohere(fs, fj);
404 final = luaK_getlabel(fs);
405 patchlistaux(fs, e->f, final, reg, p_f);
406 patchlistaux(fs, e->t, final, reg, p_t);
408 e->f = e->t = NO_JUMP;
414 void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
415 luaK_dischargevars(fs, e);
417 luaK_reserveregs(fs, 1);
418 exp2reg(fs, e, fs->freereg - 1);
422 int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
423 luaK_dischargevars(fs, e);
424 if (e->k == VNONRELOC) {
425 if (!hasjumps(e)) return e->u.s.info; /* exp is already in a register */
426 if (e->u.s.info >= fs->nactvar) { /* reg. is not a local? */
427 exp2reg(fs, e, e->u.s.info); /* put value on it */
431 luaK_exp2nextreg(fs, e); /* default */
436 void luaK_exp2val (FuncState *fs, expdesc *e) {
438 luaK_exp2anyreg(fs, e);
440 luaK_dischargevars(fs, e);
444 int luaK_exp2RK (FuncState *fs, expdesc *e) {
451 if (fs->nk <= MAXINDEXRK) { /* constant fit in RK operand? */
452 e->u.s.info = (e->k == VNIL) ? nilK(fs) :
453 (e->k == VKNUM) ? luaK_numberK(fs, e->u.nval) :
454 boolK(fs, (e->k == VTRUE));
456 return RKASK(e->u.s.info);
461 if (e->u.s.info <= MAXINDEXRK) /* constant fit in argC? */
462 return RKASK(e->u.s.info);
467 /* not a constant in the right range: put it in a register */
468 return luaK_exp2anyreg(fs, e);
472 void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
476 exp2reg(fs, ex, var->u.s.info);
480 int e = luaK_exp2anyreg(fs, ex);
481 luaK_codeABC(fs, OP_SETUPVAL, e, var->u.s.info, 0);
485 int e = luaK_exp2anyreg(fs, ex);
486 luaK_codeABx(fs, OP_SETGLOBAL, e, var->u.s.info);
490 int e = luaK_exp2RK(fs, ex);
491 luaK_codeABC(fs, OP_SETTABLE, var->u.s.info, var->u.s.aux, e);
495 lua_assert(0); /* invalid var kind to store */
503 void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
505 luaK_exp2anyreg(fs, e);
508 luaK_reserveregs(fs, 2);
509 luaK_codeABC(fs, OP_SELF, func, e->u.s.info, luaK_exp2RK(fs, key));
516 static void invertjump (FuncState *fs, expdesc *e) {
517 Instruction *pc = getjumpcontrol(fs, e->u.s.info);
518 lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
519 GET_OPCODE(*pc) != OP_TEST);
520 SETARG_A(*pc, !(GETARG_A(*pc)));
524 static int jumponcond (FuncState *fs, expdesc *e, int cond) {
525 if (e->k == VRELOCABLE) {
526 Instruction ie = getcode(fs, e);
527 if (GET_OPCODE(ie) == OP_NOT) {
528 fs->pc--; /* remove previous OP_NOT */
529 return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
531 /* else go through */
533 discharge2anyreg(fs, e);
535 return condjump(fs, OP_TESTSET, NO_REG, e->u.s.info, cond);
539 void luaK_goiftrue (FuncState *fs, expdesc *e) {
540 int pc; /* pc of last jump */
541 luaK_dischargevars(fs, e);
543 case VK: case VKNUM: case VTRUE: {
544 pc = NO_JUMP; /* always true; do nothing */
548 pc = luaK_jump(fs); /* always jump */
557 pc = jumponcond(fs, e, 0);
561 luaK_concat(fs, &e->f, pc); /* insert last jump in `f' list */
562 luaK_patchtohere(fs, e->t);
567 static void luaK_goiffalse (FuncState *fs, expdesc *e) {
568 int pc; /* pc of last jump */
569 luaK_dischargevars(fs, e);
571 case VNIL: case VFALSE: {
572 pc = NO_JUMP; /* always false; do nothing */
576 pc = luaK_jump(fs); /* always jump */
584 pc = jumponcond(fs, e, 1);
588 luaK_concat(fs, &e->t, pc); /* insert last jump in `t' list */
589 luaK_patchtohere(fs, e->f);
594 static void codenot (FuncState *fs, expdesc *e) {
595 luaK_dischargevars(fs, e);
597 case VNIL: case VFALSE: {
601 case VK: case VKNUM: case VTRUE: {
611 discharge2anyreg(fs, e);
613 e->u.s.info = luaK_codeABC(fs, OP_NOT, 0, e->u.s.info, 0);
618 lua_assert(0); /* cannot happen */
622 /* interchange true and false lists */
623 { int temp = e->f; e->f = e->t; e->t = temp; }
624 removevalues(fs, e->f);
625 removevalues(fs, e->t);
629 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
630 t->u.s.aux = luaK_exp2RK(fs, k);
635 static int constfolding (OpCode op, expdesc *e1, expdesc *e2) {
636 lua_Number v1, v2, r;
637 if (!isnumeral(e1) || !isnumeral(e2)) return 0;
641 case OP_ADD: r = luai_numadd(v1, v2); break;
642 case OP_SUB: r = luai_numsub(v1, v2); break;
643 case OP_MUL: r = luai_nummul(v1, v2); break;
645 if (v2 == 0) return 0; /* do not attempt to divide by 0 */
646 r = luai_numdiv(v1, v2); break;
648 if (v2 == 0) return 0; /* do not attempt to divide by 0 */
649 r = luai_nummod(v1, v2); break;
650 case OP_POW: r = luai_numpow(v1, v2); break;
651 case OP_UNM: r = luai_numunm(v1); break;
652 case OP_LEN: return 0; /* no constant folding for 'len' */
653 default: lua_assert(0); r = 0; break;
655 if (luai_numisnan(r)) return 0; /* do not attempt to produce NaN */
661 static void codearith (FuncState *fs, OpCode op, expdesc *e1, expdesc *e2) {
662 if (constfolding(op, e1, e2))
665 int o2 = (op != OP_UNM && op != OP_LEN) ? luaK_exp2RK(fs, e2) : 0;
666 int o1 = luaK_exp2RK(fs, e1);
675 e1->u.s.info = luaK_codeABC(fs, op, 0, o1, o2);
681 static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,
683 int o1 = luaK_exp2RK(fs, e1);
684 int o2 = luaK_exp2RK(fs, e2);
687 if (cond == 0 && op != OP_EQ) {
688 int temp; /* exchange args to replace by `<' or `<=' */
689 temp = o1; o1 = o2; o2 = temp; /* o1 <==> o2 */
692 e1->u.s.info = condjump(fs, op, cond, o1, o2);
697 void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e) {
699 e2.t = e2.f = NO_JUMP; e2.k = VKNUM; e2.u.nval = 0;
703 luaK_exp2anyreg(fs, e); /* cannot operate on non-numeric constants */
704 codearith(fs, OP_UNM, e, &e2);
707 case OPR_NOT: codenot(fs, e); break;
709 luaK_exp2anyreg(fs, e); /* cannot operate on constants */
710 codearith(fs, OP_LEN, e, &e2);
713 default: lua_assert(0);
718 void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
721 luaK_goiftrue(fs, v);
725 luaK_goiffalse(fs, v);
729 luaK_exp2nextreg(fs, v); /* operand must be on the `stack' */
732 case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:
733 case OPR_MOD: case OPR_POW: {
734 if (!isnumeral(v)) luaK_exp2RK(fs, v);
745 void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
748 lua_assert(e1->t == NO_JUMP); /* list must be closed */
749 luaK_dischargevars(fs, e2);
750 luaK_concat(fs, &e2->f, e1->f);
755 lua_assert(e1->f == NO_JUMP); /* list must be closed */
756 luaK_dischargevars(fs, e2);
757 luaK_concat(fs, &e2->t, e1->t);
762 luaK_exp2val(fs, e2);
763 if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
764 lua_assert(e1->u.s.info == GETARG_B(getcode(fs, e2))-1);
766 SETARG_B(getcode(fs, e2), e1->u.s.info);
767 e1->k = VRELOCABLE; e1->u.s.info = e2->u.s.info;
770 luaK_exp2nextreg(fs, e2); /* operand must be on the 'stack' */
771 codearith(fs, OP_CONCAT, e1, e2);
775 case OPR_ADD: codearith(fs, OP_ADD, e1, e2); break;
776 case OPR_SUB: codearith(fs, OP_SUB, e1, e2); break;
777 case OPR_MUL: codearith(fs, OP_MUL, e1, e2); break;
778 case OPR_DIV: codearith(fs, OP_DIV, e1, e2); break;
779 case OPR_MOD: codearith(fs, OP_MOD, e1, e2); break;
780 case OPR_POW: codearith(fs, OP_POW, e1, e2); break;
781 case OPR_EQ: codecomp(fs, OP_EQ, 1, e1, e2); break;
782 case OPR_NE: codecomp(fs, OP_EQ, 0, e1, e2); break;
783 case OPR_LT: codecomp(fs, OP_LT, 1, e1, e2); break;
784 case OPR_LE: codecomp(fs, OP_LE, 1, e1, e2); break;
785 case OPR_GT: codecomp(fs, OP_LT, 0, e1, e2); break;
786 case OPR_GE: codecomp(fs, OP_LE, 0, e1, e2); break;
787 default: lua_assert(0);
792 void luaK_fixline (FuncState *fs, int line) {
793 fs->f->lineinfo[fs->pc - 1] = line;
797 static int luaK_code (FuncState *fs, Instruction i, int line) {
799 dischargejpc(fs); /* `pc' will change */
800 /* put new instruction in code array */
801 luaM_growvector(fs->L, f->code, fs->pc, f->sizecode, Instruction,
802 MAX_INT, "code size overflow");
804 /* save corresponding line information */
805 luaM_growvector(fs->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
806 MAX_INT, "code size overflow");
807 f->lineinfo[fs->pc] = line;
812 int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
813 lua_assert(getOpMode(o) == iABC);
814 lua_assert(getBMode(o) != OpArgN || b == 0);
815 lua_assert(getCMode(o) != OpArgN || c == 0);
816 return luaK_code(fs, CREATE_ABC(o, a, b, c), fs->ls->lastline);
820 int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
821 lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
822 lua_assert(getCMode(o) == OpArgN);
823 return luaK_code(fs, CREATE_ABx(o, a, bc), fs->ls->lastline);
827 void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
828 int c = (nelems - 1)/LFIELDS_PER_FLUSH + 1;
829 int b = (tostore == LUA_MULTRET) ? 0 : tostore;
830 lua_assert(tostore != 0);
832 luaK_codeABC(fs, OP_SETLIST, base, b, c);
834 luaK_codeABC(fs, OP_SETLIST, base, b, 0);
835 luaK_code(fs, cast(Instruction, c), fs->ls->lastline);
837 fs->freereg = base + 1; /* free registers with list values */