2 ** $Id: lcode.c,v 2.62.1.1 2013/04/12 18:48:47 roberto Exp $
3 ** Code generator for Lua
4 ** See Copyright Notice in lua.h
29 #define hasjumps(e) ((e)->t != (e)->f)
32 static int isnumeral(expdesc *e) {
33 return (e->k == VKNUM && e->t == NO_JUMP && e->f == NO_JUMP);
37 void luaK_nil (FuncState *fs, int from, int n) {
38 Instruction *previous;
39 int l = from + n - 1; /* last register to set nil */
40 if (fs->pc > fs->lasttarget) { /* no jumps to current position? */
41 previous = &fs->f->code[fs->pc-1];
42 if (GET_OPCODE(*previous) == OP_LOADNIL) {
43 int pfrom = GETARG_A(*previous);
44 int pl = pfrom + GETARG_B(*previous);
45 if ((pfrom <= from && from <= pl + 1) ||
46 (from <= pfrom && pfrom <= l + 1)) { /* can connect both? */
47 if (pfrom < from) from = pfrom; /* from = min(from, pfrom) */
48 if (pl > l) l = pl; /* l = max(l, pl) */
49 SETARG_A(*previous, from);
50 SETARG_B(*previous, l - from);
53 } /* else go through */
55 luaK_codeABC(fs, OP_LOADNIL, 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 LUAI_FUNC void luaK_patchclose (FuncState *fs, int list, int level) {
180 level++; /* argument is +1 to reserve 0 as non-op */
181 while (list != NO_JUMP) {
182 int next = getjump(fs, list);
183 lua_assert(GET_OPCODE(fs->f->code[list]) == OP_JMP &&
184 (GETARG_A(fs->f->code[list]) == 0 ||
185 GETARG_A(fs->f->code[list]) >= level));
186 SETARG_A(fs->f->code[list], level);
192 void luaK_patchtohere (FuncState *fs, int list) {
194 luaK_concat(fs, &fs->jpc, list);
198 void luaK_concat (FuncState *fs, int *l1, int l2) {
199 if (l2 == NO_JUMP) return;
200 else if (*l1 == NO_JUMP)
205 while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */
207 fixjump(fs, list, l2);
212 static int luaK_code (FuncState *fs, Instruction i) {
214 dischargejpc(fs); /* `pc' will change */
215 /* put new instruction in code array */
216 luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction,
219 /* save corresponding line information */
220 luaM_growvector(fs->ls->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
222 f->lineinfo[fs->pc] = fs->ls->lastline;
227 int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
228 lua_assert(getOpMode(o) == iABC);
229 lua_assert(getBMode(o) != OpArgN || b == 0);
230 lua_assert(getCMode(o) != OpArgN || c == 0);
231 lua_assert(a <= MAXARG_A && b <= MAXARG_B && c <= MAXARG_C);
232 return luaK_code(fs, CREATE_ABC(o, a, b, c));
236 int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
237 lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
238 lua_assert(getCMode(o) == OpArgN);
239 lua_assert(a <= MAXARG_A && bc <= MAXARG_Bx);
240 return luaK_code(fs, CREATE_ABx(o, a, bc));
244 static int codeextraarg (FuncState *fs, int a) {
245 lua_assert(a <= MAXARG_Ax);
246 return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a));
250 int luaK_codek (FuncState *fs, int reg, int k) {
252 return luaK_codeABx(fs, OP_LOADK, reg, k);
254 int p = luaK_codeABx(fs, OP_LOADKX, reg, 0);
261 void luaK_checkstack (FuncState *fs, int n) {
262 int newstack = fs->freereg + n;
263 if (newstack > fs->f->maxstacksize) {
264 if (newstack >= MAXSTACK)
265 luaX_syntaxerror(fs->ls, "function or expression too complex");
266 fs->f->maxstacksize = cast_byte(newstack);
271 void luaK_reserveregs (FuncState *fs, int n) {
272 luaK_checkstack(fs, n);
277 static void freereg (FuncState *fs, int reg) {
278 if (!ISK(reg) && reg >= fs->nactvar) {
280 lua_assert(reg == fs->freereg);
285 static void freeexp (FuncState *fs, expdesc *e) {
286 if (e->k == VNONRELOC)
287 freereg(fs, e->u.info);
291 static int addk (FuncState *fs, TValue *key, TValue *v) {
292 lua_State *L = fs->ls->L;
293 TValue *idx = luaH_set(L, fs->h, key);
296 if (ttisnumber(idx)) {
297 lua_Number n = nvalue(idx);
298 lua_number2int(k, n);
299 if (luaV_rawequalobj(&f->k[k], v))
301 /* else may be a collision (e.g., between 0.0 and "\0\0\0\0\0\0\0\0");
302 go through and create a new entry for this value */
304 /* constant not found; create a new entry */
307 /* numerical value does not need GC barrier;
308 table has no metatable, so it does not need to invalidate cache */
309 setnvalue(idx, cast_num(k));
310 luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants");
311 while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
312 setobj(L, &f->k[k], v);
314 luaC_barrier(L, f, v);
319 int luaK_stringK (FuncState *fs, TString *s) {
321 setsvalue(fs->ls->L, &o, s);
322 return addk(fs, &o, &o);
326 int luaK_numberK (FuncState *fs, lua_Number r) {
328 lua_State *L = fs->ls->L;
331 if (r == 0 || luai_numisnan(NULL, r)) { /* handle -0 and NaN */
332 /* use raw representation as key to avoid numeric problems */
333 setsvalue(L, L->top++, luaS_newlstr(L, (char *)&r, sizeof(r)));
334 n = addk(fs, L->top - 1, &o);
338 n = addk(fs, &o, &o); /* regular case */
343 static int boolK (FuncState *fs, int b) {
346 return addk(fs, &o, &o);
350 static int nilK (FuncState *fs) {
353 /* cannot use nil as key; instead use table itself to represent nil */
354 sethvalue(fs->ls->L, &k, fs->h);
355 return addk(fs, &k, &v);
359 void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
360 if (e->k == VCALL) { /* expression is an open function call? */
361 SETARG_C(getcode(fs, e), nresults+1);
363 else if (e->k == VVARARG) {
364 SETARG_B(getcode(fs, e), nresults+1);
365 SETARG_A(getcode(fs, e), fs->freereg);
366 luaK_reserveregs(fs, 1);
371 void luaK_setoneret (FuncState *fs, expdesc *e) {
372 if (e->k == VCALL) { /* expression is an open function call? */
374 e->u.info = GETARG_A(getcode(fs, e));
376 else if (e->k == VVARARG) {
377 SETARG_B(getcode(fs, e), 2);
378 e->k = VRELOCABLE; /* can relocate its simple result */
383 void luaK_dischargevars (FuncState *fs, expdesc *e) {
390 e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0);
395 OpCode op = OP_GETTABUP; /* assume 't' is in an upvalue */
396 freereg(fs, e->u.ind.idx);
397 if (e->u.ind.vt == VLOCAL) { /* 't' is in a register? */
398 freereg(fs, e->u.ind.t);
401 e->u.info = luaK_codeABC(fs, op, 0, e->u.ind.t, e->u.ind.idx);
407 luaK_setoneret(fs, e);
410 default: break; /* there is one value available (somewhere) */
415 static int code_label (FuncState *fs, int A, int b, int jump) {
416 luaK_getlabel(fs); /* those instructions may be jump targets */
417 return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
421 static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
422 luaK_dischargevars(fs, e);
425 luaK_nil(fs, reg, 1);
428 case VFALSE: case VTRUE: {
429 luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
433 luaK_codek(fs, reg, e->u.info);
437 luaK_codek(fs, reg, luaK_numberK(fs, e->u.nval));
441 Instruction *pc = &getcode(fs, e);
446 if (reg != e->u.info)
447 luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0);
451 lua_assert(e->k == VVOID || e->k == VJMP);
452 return; /* nothing to do... */
460 static void discharge2anyreg (FuncState *fs, expdesc *e) {
461 if (e->k != VNONRELOC) {
462 luaK_reserveregs(fs, 1);
463 discharge2reg(fs, e, fs->freereg-1);
468 static void exp2reg (FuncState *fs, expdesc *e, int reg) {
469 discharge2reg(fs, e, reg);
471 luaK_concat(fs, &e->t, e->u.info); /* put this jump in `t' list */
473 int final; /* position after whole expression */
474 int p_f = NO_JUMP; /* position of an eventual LOAD false */
475 int p_t = NO_JUMP; /* position of an eventual LOAD true */
476 if (need_value(fs, e->t) || need_value(fs, e->f)) {
477 int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
478 p_f = code_label(fs, reg, 0, 1);
479 p_t = code_label(fs, reg, 1, 0);
480 luaK_patchtohere(fs, fj);
482 final = luaK_getlabel(fs);
483 patchlistaux(fs, e->f, final, reg, p_f);
484 patchlistaux(fs, e->t, final, reg, p_t);
486 e->f = e->t = NO_JUMP;
492 void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
493 luaK_dischargevars(fs, e);
495 luaK_reserveregs(fs, 1);
496 exp2reg(fs, e, fs->freereg - 1);
500 int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
501 luaK_dischargevars(fs, e);
502 if (e->k == VNONRELOC) {
503 if (!hasjumps(e)) return e->u.info; /* exp is already in a register */
504 if (e->u.info >= fs->nactvar) { /* reg. is not a local? */
505 exp2reg(fs, e, e->u.info); /* put value on it */
509 luaK_exp2nextreg(fs, e); /* default */
514 void luaK_exp2anyregup (FuncState *fs, expdesc *e) {
515 if (e->k != VUPVAL || hasjumps(e))
516 luaK_exp2anyreg(fs, e);
520 void luaK_exp2val (FuncState *fs, expdesc *e) {
522 luaK_exp2anyreg(fs, e);
524 luaK_dischargevars(fs, e);
528 int luaK_exp2RK (FuncState *fs, expdesc *e) {
534 if (fs->nk <= MAXINDEXRK) { /* constant fits in RK operand? */
535 e->u.info = (e->k == VNIL) ? nilK(fs) : boolK(fs, (e->k == VTRUE));
537 return RKASK(e->u.info);
542 e->u.info = luaK_numberK(fs, e->u.nval);
547 if (e->u.info <= MAXINDEXRK) /* constant fits in argC? */
548 return RKASK(e->u.info);
553 /* not a constant in the right range: put it in a register */
554 return luaK_exp2anyreg(fs, e);
558 void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
562 exp2reg(fs, ex, var->u.info);
566 int e = luaK_exp2anyreg(fs, ex);
567 luaK_codeABC(fs, OP_SETUPVAL, e, var->u.info, 0);
571 OpCode op = (var->u.ind.vt == VLOCAL) ? OP_SETTABLE : OP_SETTABUP;
572 int e = luaK_exp2RK(fs, ex);
573 luaK_codeABC(fs, op, var->u.ind.t, var->u.ind.idx, e);
577 lua_assert(0); /* invalid var kind to store */
585 void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
587 luaK_exp2anyreg(fs, e);
588 ereg = e->u.info; /* register where 'e' was placed */
590 e->u.info = fs->freereg; /* base register for op_self */
592 luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */
593 luaK_codeABC(fs, OP_SELF, e->u.info, ereg, luaK_exp2RK(fs, key));
598 static void invertjump (FuncState *fs, expdesc *e) {
599 Instruction *pc = getjumpcontrol(fs, e->u.info);
600 lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
601 GET_OPCODE(*pc) != OP_TEST);
602 SETARG_A(*pc, !(GETARG_A(*pc)));
606 static int jumponcond (FuncState *fs, expdesc *e, int cond) {
607 if (e->k == VRELOCABLE) {
608 Instruction ie = getcode(fs, e);
609 if (GET_OPCODE(ie) == OP_NOT) {
610 fs->pc--; /* remove previous OP_NOT */
611 return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
613 /* else go through */
615 discharge2anyreg(fs, e);
617 return condjump(fs, OP_TESTSET, NO_REG, e->u.info, cond);
621 void luaK_goiftrue (FuncState *fs, expdesc *e) {
622 int pc; /* pc of last jump */
623 luaK_dischargevars(fs, e);
630 case VK: case VKNUM: case VTRUE: {
631 pc = NO_JUMP; /* always true; do nothing */
635 pc = jumponcond(fs, e, 0);
639 luaK_concat(fs, &e->f, pc); /* insert last jump in `f' list */
640 luaK_patchtohere(fs, e->t);
645 void luaK_goiffalse (FuncState *fs, expdesc *e) {
646 int pc; /* pc of last jump */
647 luaK_dischargevars(fs, e);
653 case VNIL: case VFALSE: {
654 pc = NO_JUMP; /* always false; do nothing */
658 pc = jumponcond(fs, e, 1);
662 luaK_concat(fs, &e->t, pc); /* insert last jump in `t' list */
663 luaK_patchtohere(fs, e->f);
668 static void codenot (FuncState *fs, expdesc *e) {
669 luaK_dischargevars(fs, e);
671 case VNIL: case VFALSE: {
675 case VK: case VKNUM: case VTRUE: {
685 discharge2anyreg(fs, e);
687 e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0);
692 lua_assert(0); /* cannot happen */
696 /* interchange true and false lists */
697 { int temp = e->f; e->f = e->t; e->t = temp; }
698 removevalues(fs, e->f);
699 removevalues(fs, e->t);
703 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
704 lua_assert(!hasjumps(t));
705 t->u.ind.t = t->u.info;
706 t->u.ind.idx = luaK_exp2RK(fs, k);
707 t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL
708 : check_exp(vkisinreg(t->k), VLOCAL);
713 static int constfolding (OpCode op, expdesc *e1, expdesc *e2) {
715 if (!isnumeral(e1) || !isnumeral(e2)) return 0;
716 if ((op == OP_DIV || op == OP_MOD) && e2->u.nval == 0)
717 return 0; /* do not attempt to divide by 0 */
718 r = luaO_arith(op - OP_ADD + LUA_OPADD, e1->u.nval, e2->u.nval);
724 static void codearith (FuncState *fs, OpCode op,
725 expdesc *e1, expdesc *e2, int line) {
726 if (constfolding(op, e1, e2))
729 int o2 = (op != OP_UNM && op != OP_LEN) ? luaK_exp2RK(fs, e2) : 0;
730 int o1 = luaK_exp2RK(fs, e1);
739 e1->u.info = luaK_codeABC(fs, op, 0, o1, o2);
741 luaK_fixline(fs, line);
746 static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,
748 int o1 = luaK_exp2RK(fs, e1);
749 int o2 = luaK_exp2RK(fs, e2);
752 if (cond == 0 && op != OP_EQ) {
753 int temp; /* exchange args to replace by `<' or `<=' */
754 temp = o1; o1 = o2; o2 = temp; /* o1 <==> o2 */
757 e1->u.info = condjump(fs, op, cond, o1, o2);
762 void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) {
764 e2.t = e2.f = NO_JUMP; e2.k = VKNUM; e2.u.nval = 0;
767 if (isnumeral(e)) /* minus constant? */
768 e->u.nval = luai_numunm(NULL, e->u.nval); /* fold it */
770 luaK_exp2anyreg(fs, e);
771 codearith(fs, OP_UNM, e, &e2, line);
775 case OPR_NOT: codenot(fs, e); break;
777 luaK_exp2anyreg(fs, e); /* cannot operate on constants */
778 codearith(fs, OP_LEN, e, &e2, line);
781 default: lua_assert(0);
786 void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
789 luaK_goiftrue(fs, v);
793 luaK_goiffalse(fs, v);
797 luaK_exp2nextreg(fs, v); /* operand must be on the `stack' */
800 case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:
801 case OPR_MOD: case OPR_POW: {
802 if (!isnumeral(v)) luaK_exp2RK(fs, v);
813 void luaK_posfix (FuncState *fs, BinOpr op,
814 expdesc *e1, expdesc *e2, int line) {
817 lua_assert(e1->t == NO_JUMP); /* list must be closed */
818 luaK_dischargevars(fs, e2);
819 luaK_concat(fs, &e2->f, e1->f);
824 lua_assert(e1->f == NO_JUMP); /* list must be closed */
825 luaK_dischargevars(fs, e2);
826 luaK_concat(fs, &e2->t, e1->t);
831 luaK_exp2val(fs, e2);
832 if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
833 lua_assert(e1->u.info == GETARG_B(getcode(fs, e2))-1);
835 SETARG_B(getcode(fs, e2), e1->u.info);
836 e1->k = VRELOCABLE; e1->u.info = e2->u.info;
839 luaK_exp2nextreg(fs, e2); /* operand must be on the 'stack' */
840 codearith(fs, OP_CONCAT, e1, e2, line);
844 case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:
845 case OPR_MOD: case OPR_POW: {
846 codearith(fs, cast(OpCode, op - OPR_ADD + OP_ADD), e1, e2, line);
849 case OPR_EQ: case OPR_LT: case OPR_LE: {
850 codecomp(fs, cast(OpCode, op - OPR_EQ + OP_EQ), 1, e1, e2);
853 case OPR_NE: case OPR_GT: case OPR_GE: {
854 codecomp(fs, cast(OpCode, op - OPR_NE + OP_EQ), 0, e1, e2);
857 default: lua_assert(0);
862 void luaK_fixline (FuncState *fs, int line) {
863 fs->f->lineinfo[fs->pc - 1] = line;
867 void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
868 int c = (nelems - 1)/LFIELDS_PER_FLUSH + 1;
869 int b = (tostore == LUA_MULTRET) ? 0 : tostore;
870 lua_assert(tostore != 0);
872 luaK_codeABC(fs, OP_SETLIST, base, b, c);
873 else if (c <= MAXARG_Ax) {
874 luaK_codeABC(fs, OP_SETLIST, base, b, 0);
878 luaX_syntaxerror(fs->ls, "constructor too long");
879 fs->freereg = base + 1; /* free registers with list values */