src/lcode.c

   1 /*
   2 ** $Id: lcode.c,v 2.25a 2006/03/21 19:28:49 roberto Exp $
   3 ** Code generator for Lua
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <stdlib.h>
   9
  10 #define lcode_c
  11 #define LUA_CORE
  12
  13 #include "lua.h"
  14
  15 #include "lcode.h"
  16 #include "ldebug.h"
  17 #include "ldo.h"
  18 #include "lgc.h"
  19 #include "llex.h"
  20 #include "lmem.h"
  21 #include "lobject.h"
  22 #include "lopcodes.h"
  23 #include "lparser.h"
  24 #include "ltable.h"
  25 #include "lnum.h"
  26
  27
  28 #define hasjumps(e)     ((e)->t != (e)->f)
  29
  30 static lu_bool isnumeral(expdesc *e) {
  31   lu_bool ek=
  32 #ifdef LUA_TINT
  33     (e->k == VKINT) ||
  34 #endif
  35 #ifdef LNUM_COMPLEX
  36     (e->k == VKNUM2) ||
  37 #endif
  38     (e->k == VKNUM);
  39   return (ek && e->t == NO_JUMP && e->f == NO_JUMP);
  40 }
  41
  42
  43 void luaK_nil (FuncState *fs, int from, int n) {
  44   Instruction *previous;
  45   if (fs->pc > fs->lasttarget) {  /* no jumps to current position? */
  46     if (fs->pc == 0) {  /* function start? */
  47       if (from >= fs->nactvar)
  48         return;  /* positions are already clean */
  49     }
  50     else {
  51       previous = &fs->f->code[fs->pc-1];
  52       if (GET_OPCODE(*previous) == OP_LOADNIL) {
  53         int pfrom = GETARG_A(*previous);
  54         int pto = GETARG_B(*previous);
  55         if (pfrom <= from && from <= pto+1) {  /* can connect both? */
  56           if (from+n-1 > pto)
  57             SETARG_B(*previous, from+n-1);
  58           return;
  59         }
  60       }
  61     }
  62   }
  63   luaK_codeABC(fs, OP_LOADNIL, from, from+n-1, 0);  /* else no optimization */
  64 }
  65
  66
  67 int luaK_jump (FuncState *fs) {
  68   int jpc = fs->jpc;  /* save list of jumps to here */
  69   int j;
  70   fs->jpc = NO_JUMP;
  71   j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
  72   luaK_concat(fs, &j, jpc);  /* keep them on hold */
  73   return j;
  74 }
  75
  76
  77 void luaK_ret (FuncState *fs, int first, int nret) {
  78   luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);
  79 }
  80
  81
  82 static int condjump (FuncState *fs, OpCode op, int A, int B, int C) {
  83   luaK_codeABC(fs, op, A, B, C);
  84   return luaK_jump(fs);
  85 }
  86
  87
  88 static void fixjump (FuncState *fs, int pc, int dest) {
  89   Instruction *jmp = &fs->f->code[pc];
  90   int offset = dest-(pc+1);
  91   lua_assert(dest != NO_JUMP);
  92   if (abs(offset) > MAXARG_sBx)
  93     luaX_syntaxerror(fs->ls, "control structure too long");
  94   SETARG_sBx(*jmp, offset);
  95 }
  96
  97
  98 /*
  99 ** returns current `pc' and marks it as a jump target (to avoid wrong
 100 ** optimizations with consecutive instructions not in the same basic block).
 101 */
 102 int luaK_getlabel (FuncState *fs) {
 103   fs->lasttarget = fs->pc;
 104   return fs->pc;
 105 }
 106
 107
 108 static int getjump (FuncState *fs, int pc) {
 109   int offset = GETARG_sBx(fs->f->code[pc]);
 110   if (offset == NO_JUMP)  /* point to itself represents end of list */
 111     return NO_JUMP;  /* end of list */
 112   else
 113     return (pc+1)+offset;  /* turn offset into absolute position */
 114 }
 115
 116
 117 static Instruction *getjumpcontrol (FuncState *fs, int pc) {
 118   Instruction *pi = &fs->f->code[pc];
 119   if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))
 120     return pi-1;
 121   else
 122     return pi;
 123 }
 124
 125
 126 /*
 127 ** check whether list has any jump that do not produce a value
 128 ** (or produce an inverted value)
 129 */
 130 static lu_bool need_value (FuncState *fs, int list) {
 131   for (; list != NO_JUMP; list = getjump(fs, list)) {
 132     Instruction i = *getjumpcontrol(fs, list);
 133     if (GET_OPCODE(i) != OP_TESTSET) return 1;
 134   }
 135   return 0;  /* not found */
 136 }
 137
 138
 139 static lu_bool patchtestreg (FuncState *fs, int node, int reg) {
 140   Instruction *i = getjumpcontrol(fs, node);
 141   if (GET_OPCODE(*i) != OP_TESTSET)
 142     return 0;  /* cannot patch other instructions */
 143   if (reg != NO_REG && reg != GETARG_B(*i))
 144     SETARG_A(*i, reg);
 145   else  /* no register to put value or register already has the value */
 146     *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
 147
 148   return 1;
 149 }
 150
 151
 152 static void removevalues (FuncState *fs, int list) {
 153   for (; list != NO_JUMP; list = getjump(fs, list))
 154       patchtestreg(fs, list, NO_REG);
 155 }
 156
 157
 158 static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
 159                           int dtarget) {
 160   while (list != NO_JUMP) {
 161     int next = getjump(fs, list);
 162     if (patchtestreg(fs, list, reg))
 163       fixjump(fs, list, vtarget);
 164     else
 165       fixjump(fs, list, dtarget);  /* jump to default target */
 166     list = next;
 167   }
 168 }
 169
 170
 171 static void dischargejpc (FuncState *fs) {
 172   patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
 173   fs->jpc = NO_JUMP;
 174 }
 175
 176
 177 void luaK_patchlist (FuncState *fs, int list, int target) {
 178   if (target == fs->pc)
 179     luaK_patchtohere(fs, list);
 180   else {
 181     lua_assert(target < fs->pc);
 182     patchlistaux(fs, list, target, NO_REG, target);
 183   }
 184 }
 185
 186
 187 void luaK_patchtohere (FuncState *fs, int list) {
 188   luaK_getlabel(fs);
 189   luaK_concat(fs, &fs->jpc, list);
 190 }
 191
 192
 193 void luaK_concat (FuncState *fs, int *l1, int l2) {
 194   if (l2 == NO_JUMP) return;
 195   else if (*l1 == NO_JUMP)
 196     *l1 = l2;
 197   else {
 198     int list = *l1;
 199     int next;
 200     while ((next = getjump(fs, list)) != NO_JUMP)  /* find last element */
 201       list = next;
 202     fixjump(fs, list, l2);
 203   }
 204 }
 205
 206
 207 void luaK_checkstack (FuncState *fs, int n) {
 208   int newstack = fs->freereg + n;
 209   if (newstack > fs->f->maxstacksize) {
 210     if (newstack >= MAXSTACK)
 211       luaX_syntaxerror(fs->ls, "function or expression too complex");
 212     fs->f->maxstacksize = cast_byte(newstack);
 213   }
 214 }
 215
 216
 217 void luaK_reserveregs (FuncState *fs, int n) {
 218   luaK_checkstack(fs, n);
 219   fs->freereg += n;
 220 }
 221
 222
 223 static void freereg (FuncState *fs, int reg) {
 224   if (!ISK(reg) && reg >= fs->nactvar) {
 225     fs->freereg--;
 226     lua_assert(reg == fs->freereg);
 227   }
 228 }
 229
 230
 231 static void freeexp (FuncState *fs, expdesc *e) {
 232   if (e->k == VNONRELOC)
 233     freereg(fs, e->u.s.info);
 234 }
 235
 236
 237 static int addk (FuncState *fs, TValue *k, TValue *v) {
 238   lua_State *L = fs->L;
 239   TValue *idx = luaH_set(L, fs->h, k);
 240   Proto *f = fs->f;
 241   int oldsize = f->sizek;
 242 #ifdef LUA_TINT
 243   lua_assert( !ttisnumber_raw(idx) );
 244   if (ttisinteger(idx)) {
 245     lua_assert(luaO_rawequalObj(&fs->f->k[ (int) ivalue(idx) ], v));
 246     return ivalue(idx);
 247   }
 248 #else
 249   if (ttisnumber(idx)) {
 250     lua_assert(luaO_rawequalObj(&fs->f->k[cast_int(nvalue(idx))], v));
 251     return cast_int(nvalue(idx));
 252   }
 253 #endif
 254   else {  /* constant not found; create a new entry */
 255     setivalue(idx, fs->nk);
 256     luaM_growvector(L, f->k, fs->nk, f->sizek, TValue,
 257                     MAXARG_Bx, "constant table overflow");
 258     while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
 259     setobj(L, &f->k[fs->nk], v);
 260     luaC_barrier(L, f, v);
 261     return fs->nk++;
 262   }
 263 }
 264
 265
 266 int luaK_stringK (FuncState *fs, TString *s) {
 267   TValue o;
 268   setsvalue(fs->L, &o, s);
 269   return addk(fs, &o, &o);
 270 }
 271
 272
 273 int luaK_numberK (FuncState *fs, lua_Number r) {
 274   TValue o;
 275   setnvalue(&o, r);
 276   return addk(fs, &o, &o);
 277 }
 278
 279
 280 #ifdef LUA_TINT
 281 int luaK_integerK (FuncState *fs, lua_Integer r) {
 282   TValue o;
 283   setivalue(&o, r);
 284   return addk(fs, &o, &o);
 285 }
 286 #endif
 287
 288
 289 #ifdef LNUM_COMPLEX
 290 static int luaK_imagK (FuncState *fs, lua_Number r) {
 291   TValue o;
 292   setnvalue_complex(&o, r*I);
 293   return addk(fs, &o, &o);
 294 }
 295 #endif
 296
 297 static int boolK (FuncState *fs, int b) {
 298   TValue o;
 299   setbvalue(&o, b);
 300   return addk(fs, &o, &o);
 301 }
 302
 303
 304 static int nilK (FuncState *fs) {
 305   TValue k, v;
 306   setnilvalue(&v);
 307   /* cannot use nil as key; instead use table itself to represent nil */
 308   sethvalue(fs->L, &k, fs->h);
 309   return addk(fs, &k, &v);
 310 }
 311
 312
 313 void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
 314   if (e->k == VCALL) {  /* expression is an open function call? */
 315     SETARG_C(getcode(fs, e), nresults+1);
 316   }
 317   else if (e->k == VVARARG) {
 318     SETARG_B(getcode(fs, e), nresults+1);
 319     SETARG_A(getcode(fs, e), fs->freereg);
 320     luaK_reserveregs(fs, 1);
 321   }
 322 }
 323
 324
 325 void luaK_setoneret (FuncState *fs, expdesc *e) {
 326   if (e->k == VCALL) {  /* expression is an open function call? */
 327     e->k = VNONRELOC;
 328     e->u.s.info = GETARG_A(getcode(fs, e));
 329   }
 330   else if (e->k == VVARARG) {
 331     SETARG_B(getcode(fs, e), 2);
 332     e->k = VRELOCABLE;  /* can relocate its simple result */
 333   }
 334 }
 335
 336
 337 void luaK_dischargevars (FuncState *fs, expdesc *e) {
 338   switch (e->k) {
 339     case VLOCAL: {
 340       e->k = VNONRELOC;
 341       break;
 342     }
 343     case VUPVAL: {
 344       e->u.s.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.s.info, 0);
 345       e->k = VRELOCABLE;
 346       break;
 347     }
 348     case VGLOBAL: {
 349       e->u.s.info = luaK_codeABx(fs, OP_GETGLOBAL, 0, e->u.s.info);
 350       e->k = VRELOCABLE;
 351       break;
 352     }
 353     case VINDEXED: {
 354       freereg(fs, e->u.s.aux);
 355       freereg(fs, e->u.s.info);
 356       e->u.s.info = luaK_codeABC(fs, OP_GETTABLE, 0, e->u.s.info, e->u.s.aux);
 357       e->k = VRELOCABLE;
 358       break;
 359     }
 360     case VVARARG:
 361     case VCALL: {
 362       luaK_setoneret(fs, e);
 363       break;
 364     }
 365     default: break;  /* there is one value available (somewhere) */
 366   }
 367 }
 368
 369
 370 static int code_label (FuncState *fs, int A, int b, int jump) {
 371   luaK_getlabel(fs);  /* those instructions may be jump targets */
 372   return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
 373 }
 374
 375
 376 static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
 377   luaK_dischargevars(fs, e);
 378   switch (e->k) {
 379     case VNIL: {
 380       luaK_nil(fs, reg, 1);
 381       break;
 382     }
 383     case VFALSE:  case VTRUE: {
 384       luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
 385       break;
 386     }
 387     case VK: {
 388       luaK_codeABx(fs, OP_LOADK, reg, e->u.s.info);
 389       break;
 390     }
 391     case VKNUM: {
 392       luaK_codeABx(fs, OP_LOADK, reg, luaK_numberK(fs, e->u.nval));
 393       break;
 394     }
 395 #ifdef LUA_TINT
 396     case VKINT: {
 397       luaK_codeABx(fs, OP_LOADK, reg, luaK_integerK(fs, e->u.ival));
 398       break;
 399     }
 400 #endif
 401 #ifdef LNUM_COMPLEX
 402     case VKNUM2: {
 403       luaK_codeABx(fs, OP_LOADK, reg, luaK_imagK(fs, e->u.nval));
 404       break;
 405     }
 406 #endif
 407     case VRELOCABLE: {
 408       Instruction *pc = &getcode(fs, e);
 409       SETARG_A(*pc, reg);
 410       break;
 411     }
 412     case VNONRELOC: {
 413       if (reg != e->u.s.info)
 414         luaK_codeABC(fs, OP_MOVE, reg, e->u.s.info, 0);
 415       break;
 416     }
 417     default: {
 418       lua_assert(e->k == VVOID || e->k == VJMP);
 419       return;  /* nothing to do... */
 420     }
 421   }
 422   e->u.s.info = reg;
 423   e->k = VNONRELOC;
 424 }
 425
 426
 427 static void discharge2anyreg (FuncState *fs, expdesc *e) {
 428   if (e->k != VNONRELOC) {
 429     luaK_reserveregs(fs, 1);
 430     discharge2reg(fs, e, fs->freereg-1);
 431   }
 432 }
 433
 434
 435 static void exp2reg (FuncState *fs, expdesc *e, int reg) {
 436   discharge2reg(fs, e, reg);
 437   if (e->k == VJMP)
 438     luaK_concat(fs, &e->t, e->u.s.info);  /* put this jump in `t' list */
 439   if (hasjumps(e)) {
 440     int final;  /* position after whole expression */
 441     int p_f = NO_JUMP;  /* position of an eventual LOAD false */
 442     int p_t = NO_JUMP;  /* position of an eventual LOAD true */
 443     if (need_value(fs, e->t) || need_value(fs, e->f)) {
 444       int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
 445       p_f = code_label(fs, reg, 0, 1);
 446       p_t = code_label(fs, reg, 1, 0);
 447       luaK_patchtohere(fs, fj);
 448     }
 449     final = luaK_getlabel(fs);
 450     patchlistaux(fs, e->f, final, reg, p_f);
 451     patchlistaux(fs, e->t, final, reg, p_t);
 452   }
 453   e->f = e->t = NO_JUMP;
 454   e->u.s.info = reg;
 455   e->k = VNONRELOC;
 456 }
 457
 458
 459 void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
 460   luaK_dischargevars(fs, e);
 461   freeexp(fs, e);
 462   luaK_reserveregs(fs, 1);
 463   exp2reg(fs, e, fs->freereg - 1);
 464 }
 465
 466
 467 int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
 468   luaK_dischargevars(fs, e);
 469   if (e->k == VNONRELOC) {
 470     if (!hasjumps(e)) return e->u.s.info;  /* exp is already in a register */
 471     if (e->u.s.info >= fs->nactvar) {  /* reg. is not a local? */
 472       exp2reg(fs, e, e->u.s.info);  /* put value on it */
 473       return e->u.s.info;
 474     }
 475   }
 476   luaK_exp2nextreg(fs, e);  /* default */
 477   return e->u.s.info;
 478 }
 479
 480
 481 void luaK_exp2val (FuncState *fs, expdesc *e) {
 482   if (hasjumps(e))
 483     luaK_exp2anyreg(fs, e);
 484   else
 485     luaK_dischargevars(fs, e);
 486 }
 487
 488
 489 int luaK_exp2RK (FuncState *fs, expdesc *e) {
 490   luaK_exp2val(fs, e);
 491   switch (e->k) {
 492 #ifdef LUA_TINT
 493     case VKINT:
 494 #endif
 495 #ifdef LNUM_COMPLEX
 496     case VKNUM2:
 497 #endif
 498     case VKNUM:
 499     case VTRUE:
 500     case VFALSE:
 501     case VNIL: {
 502       if (fs->nk <= MAXINDEXRK) {  /* constant fit in RK operand? */
 503         e->u.s.info = (e->k == VNIL)  ? nilK(fs) :
 504                       (e->k == VKNUM) ? luaK_numberK(fs, e->u.nval) :
 505 #ifdef LUA_TINT
 506                       (e->k == VKINT) ? luaK_integerK(fs, e->u.ival) :
 507 #endif
 508 #ifdef LNUM_COMPLEX
 509                       (e->k == VKNUM2) ? luaK_imagK(fs, e->u.nval) :
 510 #endif
 511                                         boolK(fs, (e->k == VTRUE));
 512         e->k = VK;
 513         return RKASK(e->u.s.info);
 514       }
 515       else break;
 516     }
 517     case VK: {
 518       if (e->u.s.info <= MAXINDEXRK)  /* constant fit in argC? */
 519         return RKASK(e->u.s.info);
 520       else break;
 521     }
 522     default: break;
 523   }
 524   /* not a constant in the right range: put it in a register */
 525   return luaK_exp2anyreg(fs, e);
 526 }
 527
 528
 529 void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
 530   switch (var->k) {
 531     case VLOCAL: {
 532       freeexp(fs, ex);
 533       exp2reg(fs, ex, var->u.s.info);
 534       return;
 535     }
 536     case VUPVAL: {
 537       int e = luaK_exp2anyreg(fs, ex);
 538       luaK_codeABC(fs, OP_SETUPVAL, e, var->u.s.info, 0);
 539       break;
 540     }
 541     case VGLOBAL: {
 542       int e = luaK_exp2anyreg(fs, ex);
 543       luaK_codeABx(fs, OP_SETGLOBAL, e, var->u.s.info);
 544       break;
 545     }
 546     case VINDEXED: {
 547       int e = luaK_exp2RK(fs, ex);
 548       luaK_codeABC(fs, OP_SETTABLE, var->u.s.info, var->u.s.aux, e);
 549       break;
 550     }
 551     default: {
 552       lua_assert(0);  /* invalid var kind to store */
 553       break;
 554     }
 555   }
 556   freeexp(fs, ex);
 557 }
 558
 559
 560 void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
 561   int func;
 562   luaK_exp2anyreg(fs, e);
 563   freeexp(fs, e);
 564   func = fs->freereg;
 565   luaK_reserveregs(fs, 2);
 566   luaK_codeABC(fs, OP_SELF, func, e->u.s.info, luaK_exp2RK(fs, key));
 567   freeexp(fs, key);
 568   e->u.s.info = func;
 569   e->k = VNONRELOC;
 570 }
 571
 572
 573 static void invertjump (FuncState *fs, expdesc *e) {
 574   Instruction *pc = getjumpcontrol(fs, e->u.s.info);
 575   lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
 576                                            GET_OPCODE(*pc) != OP_TEST);
 577   SETARG_A(*pc, !(GETARG_A(*pc)));
 578 }
 579
 580
 581 static int jumponcond (FuncState *fs, expdesc *e, int cond) {
 582   if (e->k == VRELOCABLE) {
 583     Instruction ie = getcode(fs, e);
 584     if (GET_OPCODE(ie) == OP_NOT) {
 585       fs->pc--;  /* remove previous OP_NOT */
 586       return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
 587     }
 588     /* else go through */
 589   }
 590   discharge2anyreg(fs, e);
 591   freeexp(fs, e);
 592   return condjump(fs, OP_TESTSET, NO_REG, e->u.s.info, cond);
 593 }
 594
 595
 596 void luaK_goiftrue (FuncState *fs, expdesc *e) {
 597   int pc;  /* pc of last jump */
 598   luaK_dischargevars(fs, e);
 599   switch (e->k) {
 600 #ifdef LNUM_COMPLEX
 601     case VKNUM2:
 602 #endif
 603 #ifdef LUA_TINT
 604     case VKINT:
 605 #endif
 606     case VK: case VKNUM: case VTRUE: {
 607       pc = NO_JUMP;  /* always true; do nothing */
 608       break;
 609     }
 610     case VFALSE: {
 611       pc = luaK_jump(fs);  /* always jump */
 612       break;
 613     }
 614     case VJMP: {
 615       invertjump(fs, e);
 616       pc = e->u.s.info;
 617       break;
 618     }
 619     default: {
 620       pc = jumponcond(fs, e, 0);
 621       break;
 622     }
 623   }
 624   luaK_concat(fs, &e->f, pc);  /* insert last jump in `f' list */
 625   luaK_patchtohere(fs, e->t);
 626   e->t = NO_JUMP;
 627 }
 628
 629
 630 static void luaK_goiffalse (FuncState *fs, expdesc *e) {
 631   int pc;  /* pc of last jump */
 632   luaK_dischargevars(fs, e);
 633   switch (e->k) {
 634     case VNIL: case VFALSE: {
 635       pc = NO_JUMP;  /* always false; do nothing */
 636       break;
 637     }
 638     case VTRUE: {
 639       pc = luaK_jump(fs);  /* always jump */
 640       break;
 641     }
 642     case VJMP: {
 643       pc = e->u.s.info;
 644       break;
 645     }
 646     default: {
 647       pc = jumponcond(fs, e, 1);
 648       break;
 649     }
 650   }
 651   luaK_concat(fs, &e->t, pc);  /* insert last jump in `t' list */
 652   luaK_patchtohere(fs, e->f);
 653   e->f = NO_JUMP;
 654 }
 655
 656
 657 static void codenot (FuncState *fs, expdesc *e) {
 658   luaK_dischargevars(fs, e);
 659   switch (e->k) {
 660     case VNIL: case VFALSE: {
 661       e->k = VTRUE;
 662       break;
 663     }
 664 #ifdef LNUM_COMPLEX
 665     case VKNUM2:
 666 #endif
 667 #ifdef LUA_TINT
 668     case VKINT:
 669 #endif
 670     case VK: case VKNUM: case VTRUE: {
 671       e->k = VFALSE;
 672       break;
 673     }
 674     case VJMP: {
 675       invertjump(fs, e);
 676       break;
 677     }
 678     case VRELOCABLE:
 679     case VNONRELOC: {
 680       discharge2anyreg(fs, e);
 681       freeexp(fs, e);
 682       e->u.s.info = luaK_codeABC(fs, OP_NOT, 0, e->u.s.info, 0);
 683       e->k = VRELOCABLE;
 684       break;
 685     }
 686     default: {
 687       lua_assert(0);  /* cannot happen */
 688       break;
 689     }
 690   }
 691   /* interchange true and false lists */
 692   { int temp = e->f; e->f = e->t; e->t = temp; }
 693   removevalues(fs, e->f);
 694   removevalues(fs, e->t);
 695 }
 696
 697
 698 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
 699   t->u.s.aux = luaK_exp2RK(fs, k);
 700   t->k = VINDEXED;
 701 }
 702
 703
 704 static lu_bool constfolding (OpCode op, expdesc *e1, expdesc *e2) {
 705   lua_Number v1, v2, r;
 706   int vkres= VKNUM;
 707   if (!isnumeral(e1) || !isnumeral(e2)) return 0;
 708
 709   /* real and imaginary parts don't mix. */
 710 #ifdef LNUM_COMPLEX
 711   if (e1->k == VKNUM2) {
 712     if ((op != OP_UNM) && (e2->k != VKNUM2)) return 0;
 713     vkres= VKNUM2; }
 714   else if (e2->k == VKNUM2) { return 0; }
 715 #endif
 716 #ifdef LUA_TINT
 717   if ((e1->k == VKINT) && (e2->k == VKINT)) {
 718     lua_Integer i1= e1->u.ival, i2= e2->u.ival;
 719     lua_Integer rr;
 720     lu_bool done= 0;
 721     /* Integer/integer calculations (maybe end up producing floating point) */
 722     switch (op) {
 723       case OP_ADD: done= try_addint( &rr, i1, i2 ); break;
 724       case OP_SUB: done= try_subint( &rr, i1, i2 ); break;
 725       case OP_MUL: done= try_mulint( &rr, i1, i2 ); break;
 726       case OP_DIV: done= try_divint( &rr, i1, i2 ); break;
 727       case OP_MOD: done= try_modint( &rr, i1, i2 ); break;
 728       case OP_POW: done= try_powint( &rr, i1, i2 ); break;
 729       case OP_UNM: done= try_unmint( &rr, i1 ); break;
 730       default:     done= 0; break;
 731     }
 732     if (done) {
 733       e1->u.ival = rr;  /* We remained within integer range, and accuracy! */
 734       return 1;
 735     }
 736   }
 737   v1 = (e1->k == VKINT) ? ((lua_Number)e1->u.ival) : e1->u.nval;
 738   v2 = (e2->k == VKINT) ? ((lua_Number)e2->u.ival) : e2->u.nval;
 739 #else
 740   v1 = e1->u.nval;
 741   v2 = e2->u.nval;
 742 #endif
 743   switch (op) {
 744     case OP_ADD: r = luai_numadd(v1, v2); break;
 745     case OP_SUB: r = luai_numsub(v1, v2); break;
 746     case OP_MUL:
 747 #ifdef LNUM_COMPLEX
 748         if (vkres==VKNUM2) return 0;    /* leave to runtime (could do here, but not worth it?) */
 749 #endif
 750         r = luai_nummul(v1, v2); break;
 751     case OP_DIV:
 752       if (v2 == 0) return 0;  /* do not attempt to divide by 0 */
 753 #ifdef LNUM_COMPLEX
 754         if (vkres==VKNUM2) return 0;    /* leave to runtime */
 755 #endif
 756         r = luai_numdiv(v1, v2); break;
 757     case OP_MOD:
 758       if (v2 == 0) return 0;  /* do not attempt to divide by 0 */
 759 #ifdef LNUM_COMPLEX
 760       if (vkres==VKNUM2) return 0;    /* leave to runtime */
 761 #endif
 762       r = luai_nummod(v1, v2); break;
 763     case OP_POW:
 764 #ifdef LNUM_COMPLEX
 765       if (vkres==VKNUM2) return 0;    /* leave to runtime */
 766 #endif
 767       r = luai_numpow(v1, v2); break;
 768     case OP_UNM: r = luai_numunm(v1); break;
 769     case OP_LEN: return 0;  /* no constant folding for 'len' */
 770     default: lua_assert(0); r = 0; break;
 771   }
 772   if (luai_numisnan(r)) return 0;  /* do not attempt to produce NaN */
 773   e1->k = (expkind) vkres;  // (Visual C++ 2005 needs the cast, on 64-bit ints)
 774   e1->u.nval = r;
 775   return 1;
 776 }
 777
 778
 779 static void codearith (FuncState *fs, OpCode op, expdesc *e1, expdesc *e2) {
 780   if (constfolding(op, e1, e2))
 781     return;
 782   else {
 783     int o2 = (op != OP_UNM && op != OP_LEN) ? luaK_exp2RK(fs, e2) : 0;
 784     int o1 = luaK_exp2RK(fs, e1);
 785     if (o1 > o2) {
 786       freeexp(fs, e1);
 787       freeexp(fs, e2);
 788     }
 789     else {
 790       freeexp(fs, e2);
 791       freeexp(fs, e1);
 792     }
 793     e1->u.s.info = luaK_codeABC(fs, op, 0, o1, o2);
 794     e1->k = VRELOCABLE;
 795   }
 796 }
 797
 798
 799 static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,
 800                                                           expdesc *e2) {
 801   int o1 = luaK_exp2RK(fs, e1);
 802   int o2 = luaK_exp2RK(fs, e2);
 803   freeexp(fs, e2);
 804   freeexp(fs, e1);
 805   if (cond == 0 && op != OP_EQ) {
 806     int temp;  /* exchange args to replace by `<' or `<=' */
 807     temp = o1; o1 = o2; o2 = temp;  /* o1 <==> o2 */
 808     cond = 1;
 809   }
 810   e1->u.s.info = condjump(fs, op, cond, o1, o2);
 811   e1->k = VJMP;
 812 }
 813
 814
 815 void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e) {
 816   /* Q: is the 'e2' really needed; couldn't we use 'e' for both params like
 817    *    when calling 'Arith()' at lvm.c */
 818   expdesc e2;
 819   e2.t = e2.f = NO_JUMP;
 820 #ifdef LUA_TINT
 821   e2.k = VKINT; e2.u.ival = 0;
 822 #else
 823   e2.k = VKNUM; e2.u.nval = 0;
 824 #endif
 825   switch (op) {
 826     case OPR_MINUS: {
 827       if (e->k == VK)
 828         luaK_exp2anyreg(fs, e);  /* cannot operate on non-numeric constants */
 829       codearith(fs, OP_UNM, e, &e2);
 830       break;
 831     }
 832     case OPR_NOT: codenot(fs, e); break;
 833     case OPR_LEN: {
 834       luaK_exp2anyreg(fs, e);  /* cannot operate on constants */
 835       codearith(fs, OP_LEN, e, &e2);
 836       break;
 837     }
 838     default: lua_assert(0);
 839   }
 840 }
 841
 842
 843 void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
 844   switch (op) {
 845     case OPR_AND: {
 846       luaK_goiftrue(fs, v);
 847       break;
 848     }
 849     case OPR_OR: {
 850       luaK_goiffalse(fs, v);
 851       break;
 852     }
 853     case OPR_CONCAT: {
 854       luaK_exp2nextreg(fs, v);  /* operand must be on the `stack' */
 855       break;
 856     }
 857     case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:
 858     case OPR_MOD: case OPR_POW: {
 859       if (!isnumeral(v)) luaK_exp2RK(fs, v);
 860       break;
 861     }
 862     default: {
 863       luaK_exp2RK(fs, v);
 864       break;
 865     }
 866   }
 867 }
 868
 869
 870 void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
 871   switch (op) {
 872     case OPR_AND: {
 873       lua_assert(e1->t == NO_JUMP);  /* list must be closed */
 874       luaK_dischargevars(fs, e2);
 875       luaK_concat(fs, &e2->f, e1->f);
 876       *e1 = *e2;
 877       break;
 878     }
 879     case OPR_OR: {
 880       lua_assert(e1->f == NO_JUMP);  /* list must be closed */
 881       luaK_dischargevars(fs, e2);
 882       luaK_concat(fs, &e2->t, e1->t);
 883       *e1 = *e2;
 884       break;
 885     }
 886     case OPR_CONCAT: {
 887       luaK_exp2val(fs, e2);
 888       if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
 889         lua_assert(e1->u.s.info == GETARG_B(getcode(fs, e2))-1);
 890         freeexp(fs, e1);
 891         SETARG_B(getcode(fs, e2), e1->u.s.info);
 892         e1->k = VRELOCABLE; e1->u.s.info = e2->u.s.info;
 893       }
 894       else {
 895         luaK_exp2nextreg(fs, e2);  /* operand must be on the 'stack' */
 896         codearith(fs, OP_CONCAT, e1, e2);
 897       }
 898       break;
 899     }
 900     case OPR_ADD:
 901     codearith(fs, OP_ADD, e1, e2); break;
 902     case OPR_SUB: codearith(fs, OP_SUB, e1, e2); break;
 903     case OPR_MUL: codearith(fs, OP_MUL, e1, e2); break;
 904     case OPR_DIV: codearith(fs, OP_DIV, e1, e2); break;
 905     case OPR_MOD: codearith(fs, OP_MOD, e1, e2); break;
 906     case OPR_POW: codearith(fs, OP_POW, e1, e2); break;
 907     case OPR_EQ: codecomp(fs, OP_EQ, 1, e1, e2); break;
 908     case OPR_NE: codecomp(fs, OP_EQ, 0, e1, e2); break;
 909     case OPR_LT: codecomp(fs, OP_LT, 1, e1, e2); break;
 910     case OPR_LE: codecomp(fs, OP_LE, 1, e1, e2); break;
 911     case OPR_GT: codecomp(fs, OP_LT, 0, e1, e2); break;
 912     case OPR_GE: codecomp(fs, OP_LE, 0, e1, e2); break;
 913     default: lua_assert(0);
 914   }
 915 }
 916
 917
 918 void luaK_fixline (FuncState *fs, int line) {
 919   fs->f->lineinfo[fs->pc - 1] = line;
 920 }
 921
 922
 923 static int luaK_code (FuncState *fs, Instruction i, int line) {
 924   Proto *f = fs->f;
 925   dischargejpc(fs);  /* `pc' will change */
 926   /* put new instruction in code array */
 927   luaM_growvector(fs->L, f->code, fs->pc, f->sizecode, Instruction,
 928                   MAX_INT, "code size overflow");
 929   f->code[fs->pc] = i;
 930   /* save corresponding line information */
 931   luaM_growvector(fs->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
 932                   MAX_INT, "code size overflow");
 933   f->lineinfo[fs->pc] = line;
 934   return fs->pc++;
 935 }
 936
 937
 938 int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
 939   lua_assert(getOpMode(o) == iABC);
 940   lua_assert(getBMode(o) != OpArgN || b == 0);
 941   lua_assert(getCMode(o) != OpArgN || c == 0);
 942   return luaK_code(fs, CREATE_ABC(o, a, b, c), fs->ls->lastline);
 943 }
 944
 945
 946 int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
 947   lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
 948   lua_assert(getCMode(o) == OpArgN);
 949   return luaK_code(fs, CREATE_ABx(o, a, bc), fs->ls->lastline);
 950 }
 951
 952
 953 void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
 954   int c =  (nelems - 1)/LFIELDS_PER_FLUSH + 1;
 955   int b = (tostore == LUA_MULTRET) ? 0 : tostore;
 956   lua_assert(tostore != 0);
 957   if (c <= MAXARG_C)
 958     luaK_codeABC(fs, OP_SETLIST, base, b, c);
 959   else {
 960     luaK_codeABC(fs, OP_SETLIST, base, b, 0);
 961     luaK_code(fs, cast(Instruction, c), fs->ls->lastline);
 962   }
 963   fs->freereg = base + 1;  /* free registers with list values */
 964 }
 965