external/mit/lua/dist/src/lcode.c

   1 /*      $NetBSD: lcode.c,v 1.1.1.2 2012/03/15 00:08:11 alnsn Exp $      */
   2
   3 /*
   4 ** $Id: lcode.c,v 1.1.1.2 2012/03/15 00:08:11 alnsn Exp $
   5 ** Code generator for Lua
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9
  10 #include <stdlib.h>
  11
  12 #define lcode_c
  13 #define LUA_CORE
  14
  15 #include "lua.h"
  16
  17 #include "lcode.h"
  18 #include "ldebug.h"
  19 #include "ldo.h"
  20 #include "lgc.h"
  21 #include "llex.h"
  22 #include "lmem.h"
  23 #include "lobject.h"
  24 #include "lopcodes.h"
  25 #include "lparser.h"
  26 #include "ltable.h"
  27
  28
  29 #define hasjumps(e)     ((e)->t != (e)->f)
  30
  31
  32 static int isnumeral(expdesc *e) {
  33   return (e->k == VKNUM && e->t == NO_JUMP && e->f == NO_JUMP);
  34 }
  35
  36
  37 void luaK_nil (FuncState *fs, int from, int n) {
  38   Instruction *previous;
  39   if (fs->pc > fs->lasttarget) {  /* no jumps to current position? */
  40     if (fs->pc == 0) {  /* function start? */
  41       if (from >= fs->nactvar)
  42         return;  /* positions are already clean */
  43     }
  44     else {
  45       previous = &fs->f->code[fs->pc-1];
  46       if (GET_OPCODE(*previous) == OP_LOADNIL) {
  47         int pfrom = GETARG_A(*previous);
  48         int pto = GETARG_B(*previous);
  49         if (pfrom <= from && from <= pto+1) {  /* can connect both? */
  50           if (from+n-1 > pto)
  51             SETARG_B(*previous, from+n-1);
  52           return;
  53         }
  54       }
  55     }
  56   }
  57   luaK_codeABC(fs, OP_LOADNIL, from, from+n-1, 0);  /* else no optimization */
  58 }
  59
  60
  61 int luaK_jump (FuncState *fs) {
  62   int jpc = fs->jpc;  /* save list of jumps to here */
  63   int j;
  64   fs->jpc = NO_JUMP;
  65   j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
  66   luaK_concat(fs, &j, jpc);  /* keep them on hold */
  67   return j;
  68 }
  69
  70
  71 void luaK_ret (FuncState *fs, int first, int nret) {
  72   luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);
  73 }
  74
  75
  76 static int condjump (FuncState *fs, OpCode op, int A, int B, int C) {
  77   luaK_codeABC(fs, op, A, B, C);
  78   return luaK_jump(fs);
  79 }
  80
  81
  82 static void fixjump (FuncState *fs, int pc, int dest) {
  83   Instruction *jmp = &fs->f->code[pc];
  84   int offset = dest-(pc+1);
  85   lua_assert(dest != NO_JUMP);
  86   if (abs(offset) > MAXARG_sBx)
  87     luaX_syntaxerror(fs->ls, "control structure too long");
  88   SETARG_sBx(*jmp, offset);
  89 }
  90
  91
  92 /*
  93 ** returns current `pc' and marks it as a jump target (to avoid wrong
  94 ** optimizations with consecutive instructions not in the same basic block).
  95 */
  96 int luaK_getlabel (FuncState *fs) {
  97   fs->lasttarget = fs->pc;
  98   return fs->pc;
  99 }
 100
 101
 102 static int getjump (FuncState *fs, int pc) {
 103   int offset = GETARG_sBx(fs->f->code[pc]);
 104   if (offset == NO_JUMP)  /* point to itself represents end of list */
 105     return NO_JUMP;  /* end of list */
 106   else
 107     return (pc+1)+offset;  /* turn offset into absolute position */
 108 }
 109
 110
 111 static Instruction *getjumpcontrol (FuncState *fs, int pc) {
 112   Instruction *pi = &fs->f->code[pc];
 113   if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))
 114     return pi-1;
 115   else
 116     return pi;
 117 }
 118
 119
 120 /*
 121 ** check whether list has any jump that do not produce a value
 122 ** (or produce an inverted value)
 123 */
 124 static int need_value (FuncState *fs, int list) {
 125   for (; list != NO_JUMP; list = getjump(fs, list)) {
 126     Instruction i = *getjumpcontrol(fs, list);
 127     if (GET_OPCODE(i) != OP_TESTSET) return 1;
 128   }
 129   return 0;  /* not found */
 130 }
 131
 132
 133 static int patchtestreg (FuncState *fs, int node, int reg) {
 134   Instruction *i = getjumpcontrol(fs, node);
 135   if (GET_OPCODE(*i) != OP_TESTSET)
 136     return 0;  /* cannot patch other instructions */
 137   if (reg != NO_REG && reg != GETARG_B(*i))
 138     SETARG_A(*i, reg);
 139   else  /* no register to put value or register already has the value */
 140     *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
 141
 142   return 1;
 143 }
 144
 145
 146 static void removevalues (FuncState *fs, int list) {
 147   for (; list != NO_JUMP; list = getjump(fs, list))
 148       patchtestreg(fs, list, NO_REG);
 149 }
 150
 151
 152 static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
 153                           int dtarget) {
 154   while (list != NO_JUMP) {
 155     int next = getjump(fs, list);
 156     if (patchtestreg(fs, list, reg))
 157       fixjump(fs, list, vtarget);
 158     else
 159       fixjump(fs, list, dtarget);  /* jump to default target */
 160     list = next;
 161   }
 162 }
 163
 164
 165 static void dischargejpc (FuncState *fs) {
 166   patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
 167   fs->jpc = NO_JUMP;
 168 }
 169
 170
 171 void luaK_patchlist (FuncState *fs, int list, int target) {
 172   if (target == fs->pc)
 173     luaK_patchtohere(fs, list);
 174   else {
 175     lua_assert(target < fs->pc);
 176     patchlistaux(fs, list, target, NO_REG, target);
 177   }
 178 }
 179
 180
 181 void luaK_patchtohere (FuncState *fs, int list) {
 182   luaK_getlabel(fs);
 183   luaK_concat(fs, &fs->jpc, list);
 184 }
 185
 186
 187 void luaK_concat (FuncState *fs, int *l1, int l2) {
 188   if (l2 == NO_JUMP) return;
 189   else if (*l1 == NO_JUMP)
 190     *l1 = l2;
 191   else {
 192     int list = *l1;
 193     int next;
 194     while ((next = getjump(fs, list)) != NO_JUMP)  /* find last element */
 195       list = next;
 196     fixjump(fs, list, l2);
 197   }
 198 }
 199
 200
 201 void luaK_checkstack (FuncState *fs, int n) {
 202   int newstack = fs->freereg + n;
 203   if (newstack > fs->f->maxstacksize) {
 204     if (newstack >= MAXSTACK)
 205       luaX_syntaxerror(fs->ls, "function or expression too complex");
 206     fs->f->maxstacksize = cast_byte(newstack);
 207   }
 208 }
 209
 210
 211 void luaK_reserveregs (FuncState *fs, int n) {
 212   luaK_checkstack(fs, n);
 213   fs->freereg += n;
 214 }
 215
 216
 217 static void freereg (FuncState *fs, int reg) {
 218   if (!ISK(reg) && reg >= fs->nactvar) {
 219     fs->freereg--;
 220     lua_assert(reg == fs->freereg);
 221   }
 222 }
 223
 224
 225 static void freeexp (FuncState *fs, expdesc *e) {
 226   if (e->k == VNONRELOC)
 227     freereg(fs, e->u.s.info);
 228 }
 229
 230
 231 static int addk (FuncState *fs, TValue *k, TValue *v) {
 232   lua_State *L = fs->L;
 233   TValue *idx = luaH_set(L, fs->h, k);
 234   Proto *f = fs->f;
 235   int oldsize = f->sizek;
 236   if (ttisnumber(idx)) {
 237     lua_assert(luaO_rawequalObj(&fs->f->k[cast_int(nvalue(idx))], v));
 238     return cast_int(nvalue(idx));
 239   }
 240   else {  /* constant not found; create a new entry */
 241     setnvalue(idx, cast_num(fs->nk));
 242     luaM_growvector(L, f->k, fs->nk, f->sizek, TValue,
 243                     MAXARG_Bx, "constant table overflow");
 244     while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
 245     setobj(L, &f->k[fs->nk], v);
 246     luaC_barrier(L, f, v);
 247     return fs->nk++;
 248   }
 249 }
 250
 251
 252 int luaK_stringK (FuncState *fs, TString *s) {
 253   TValue o;
 254   setsvalue(fs->L, &o, s);
 255   return addk(fs, &o, &o);
 256 }
 257
 258
 259 int luaK_numberK (FuncState *fs, lua_Number r) {
 260   TValue o;
 261   setnvalue(&o, r);
 262   return addk(fs, &o, &o);
 263 }
 264
 265
 266 static int boolK (FuncState *fs, int b) {
 267   TValue o;
 268   setbvalue(&o, b);
 269   return addk(fs, &o, &o);
 270 }
 271
 272
 273 static int nilK (FuncState *fs) {
 274   TValue k, v;
 275   setnilvalue(&v);
 276   /* cannot use nil as key; instead use table itself to represent nil */
 277   sethvalue(fs->L, &k, fs->h);
 278   return addk(fs, &k, &v);
 279 }
 280
 281
 282 void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
 283   if (e->k == VCALL) {  /* expression is an open function call? */
 284     SETARG_C(getcode(fs, e), nresults+1);
 285   }
 286   else if (e->k == VVARARG) {
 287     SETARG_B(getcode(fs, e), nresults+1);
 288     SETARG_A(getcode(fs, e), fs->freereg);
 289     luaK_reserveregs(fs, 1);
 290   }
 291 }
 292
 293
 294 void luaK_setoneret (FuncState *fs, expdesc *e) {
 295   if (e->k == VCALL) {  /* expression is an open function call? */
 296     e->k = VNONRELOC;
 297     e->u.s.info = GETARG_A(getcode(fs, e));
 298   }
 299   else if (e->k == VVARARG) {
 300     SETARG_B(getcode(fs, e), 2);
 301     e->k = VRELOCABLE;  /* can relocate its simple result */
 302   }
 303 }
 304
 305
 306 void luaK_dischargevars (FuncState *fs, expdesc *e) {
 307   switch (e->k) {
 308     case VLOCAL: {
 309       e->k = VNONRELOC;
 310       break;
 311     }
 312     case VUPVAL: {
 313       e->u.s.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.s.info, 0);
 314       e->k = VRELOCABLE;
 315       break;
 316     }
 317     case VGLOBAL: {
 318       e->u.s.info = luaK_codeABx(fs, OP_GETGLOBAL, 0, e->u.s.info);
 319       e->k = VRELOCABLE;
 320       break;
 321     }
 322     case VINDEXED: {
 323       freereg(fs, e->u.s.aux);
 324       freereg(fs, e->u.s.info);
 325       e->u.s.info = luaK_codeABC(fs, OP_GETTABLE, 0, e->u.s.info, e->u.s.aux);
 326       e->k = VRELOCABLE;
 327       break;
 328     }
 329     case VVARARG:
 330     case VCALL: {
 331       luaK_setoneret(fs, e);
 332       break;
 333     }
 334     default: break;  /* there is one value available (somewhere) */
 335   }
 336 }
 337
 338
 339 static int code_label (FuncState *fs, int A, int b, int jump) {
 340   luaK_getlabel(fs);  /* those instructions may be jump targets */
 341   return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
 342 }
 343
 344
 345 static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
 346   luaK_dischargevars(fs, e);
 347   switch (e->k) {
 348     case VNIL: {
 349       luaK_nil(fs, reg, 1);
 350       break;
 351     }
 352     case VFALSE:  case VTRUE: {
 353       luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
 354       break;
 355     }
 356     case VK: {
 357       luaK_codeABx(fs, OP_LOADK, reg, e->u.s.info);
 358       break;
 359     }
 360     case VKNUM: {
 361       luaK_codeABx(fs, OP_LOADK, reg, luaK_numberK(fs, e->u.nval));
 362       break;
 363     }
 364     case VRELOCABLE: {
 365       Instruction *pc = &getcode(fs, e);
 366       SETARG_A(*pc, reg);
 367       break;
 368     }
 369     case VNONRELOC: {
 370       if (reg != e->u.s.info)
 371         luaK_codeABC(fs, OP_MOVE, reg, e->u.s.info, 0);
 372       break;
 373     }
 374     default: {
 375       lua_assert(e->k == VVOID || e->k == VJMP);
 376       return;  /* nothing to do... */
 377     }
 378   }
 379   e->u.s.info = reg;
 380   e->k = VNONRELOC;
 381 }
 382
 383
 384 static void discharge2anyreg (FuncState *fs, expdesc *e) {
 385   if (e->k != VNONRELOC) {
 386     luaK_reserveregs(fs, 1);
 387     discharge2reg(fs, e, fs->freereg-1);
 388   }
 389 }
 390
 391
 392 static void exp2reg (FuncState *fs, expdesc *e, int reg) {
 393   discharge2reg(fs, e, reg);
 394   if (e->k == VJMP)
 395     luaK_concat(fs, &e->t, e->u.s.info);  /* put this jump in `t' list */
 396   if (hasjumps(e)) {
 397     int final;  /* position after whole expression */
 398     int p_f = NO_JUMP;  /* position of an eventual LOAD false */
 399     int p_t = NO_JUMP;  /* position of an eventual LOAD true */
 400     if (need_value(fs, e->t) || need_value(fs, e->f)) {
 401       int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
 402       p_f = code_label(fs, reg, 0, 1);
 403       p_t = code_label(fs, reg, 1, 0);
 404       luaK_patchtohere(fs, fj);
 405     }
 406     final = luaK_getlabel(fs);
 407     patchlistaux(fs, e->f, final, reg, p_f);
 408     patchlistaux(fs, e->t, final, reg, p_t);
 409   }
 410   e->f = e->t = NO_JUMP;
 411   e->u.s.info = reg;
 412   e->k = VNONRELOC;
 413 }
 414
 415
 416 void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
 417   luaK_dischargevars(fs, e);
 418   freeexp(fs, e);
 419   luaK_reserveregs(fs, 1);
 420   exp2reg(fs, e, fs->freereg - 1);
 421 }
 422
 423
 424 int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
 425   luaK_dischargevars(fs, e);
 426   if (e->k == VNONRELOC) {
 427     if (!hasjumps(e)) return e->u.s.info;  /* exp is already in a register */
 428     if (e->u.s.info >= fs->nactvar) {  /* reg. is not a local? */
 429       exp2reg(fs, e, e->u.s.info);  /* put value on it */
 430       return e->u.s.info;
 431     }
 432   }
 433   luaK_exp2nextreg(fs, e);  /* default */
 434   return e->u.s.info;
 435 }
 436
 437
 438 void luaK_exp2val (FuncState *fs, expdesc *e) {
 439   if (hasjumps(e))
 440     luaK_exp2anyreg(fs, e);
 441   else
 442     luaK_dischargevars(fs, e);
 443 }
 444
 445
 446 int luaK_exp2RK (FuncState *fs, expdesc *e) {
 447   luaK_exp2val(fs, e);
 448   switch (e->k) {
 449     case VKNUM:
 450     case VTRUE:
 451     case VFALSE:
 452     case VNIL: {
 453       if (fs->nk <= MAXINDEXRK) {  /* constant fit in RK operand? */
 454         e->u.s.info = (e->k == VNIL)  ? nilK(fs) :
 455                       (e->k == VKNUM) ? luaK_numberK(fs, e->u.nval) :
 456                                         boolK(fs, (e->k == VTRUE));
 457         e->k = VK;
 458         return RKASK(e->u.s.info);
 459       }
 460       else break;
 461     }
 462     case VK: {
 463       if (e->u.s.info <= MAXINDEXRK)  /* constant fit in argC? */
 464         return RKASK(e->u.s.info);
 465       else break;
 466     }
 467     default: break;
 468   }
 469   /* not a constant in the right range: put it in a register */
 470   return luaK_exp2anyreg(fs, e);
 471 }
 472
 473
 474 void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
 475   switch (var->k) {
 476     case VLOCAL: {
 477       freeexp(fs, ex);
 478       exp2reg(fs, ex, var->u.s.info);
 479       return;
 480     }
 481     case VUPVAL: {
 482       int e = luaK_exp2anyreg(fs, ex);
 483       luaK_codeABC(fs, OP_SETUPVAL, e, var->u.s.info, 0);
 484       break;
 485     }
 486     case VGLOBAL: {
 487       int e = luaK_exp2anyreg(fs, ex);
 488       luaK_codeABx(fs, OP_SETGLOBAL, e, var->u.s.info);
 489       break;
 490     }
 491     case VINDEXED: {
 492       int e = luaK_exp2RK(fs, ex);
 493       luaK_codeABC(fs, OP_SETTABLE, var->u.s.info, var->u.s.aux, e);
 494       break;
 495     }
 496     default: {
 497       lua_assert(0);  /* invalid var kind to store */
 498       break;
 499     }
 500   }
 501   freeexp(fs, ex);
 502 }
 503
 504
 505 void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
 506   int func;
 507   luaK_exp2anyreg(fs, e);
 508   freeexp(fs, e);
 509   func = fs->freereg;
 510   luaK_reserveregs(fs, 2);
 511   luaK_codeABC(fs, OP_SELF, func, e->u.s.info, luaK_exp2RK(fs, key));
 512   freeexp(fs, key);
 513   e->u.s.info = func;
 514   e->k = VNONRELOC;
 515 }
 516
 517
 518 static void invertjump (FuncState *fs, expdesc *e) {
 519   Instruction *pc = getjumpcontrol(fs, e->u.s.info);
 520   lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
 521                                            GET_OPCODE(*pc) != OP_TEST);
 522   SETARG_A(*pc, !(GETARG_A(*pc)));
 523 }
 524
 525
 526 static int jumponcond (FuncState *fs, expdesc *e, int cond) {
 527   if (e->k == VRELOCABLE) {
 528     Instruction ie = getcode(fs, e);
 529     if (GET_OPCODE(ie) == OP_NOT) {
 530       fs->pc--;  /* remove previous OP_NOT */
 531       return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
 532     }
 533     /* else go through */
 534   }
 535   discharge2anyreg(fs, e);
 536   freeexp(fs, e);
 537   return condjump(fs, OP_TESTSET, NO_REG, e->u.s.info, cond);
 538 }
 539
 540
 541 void luaK_goiftrue (FuncState *fs, expdesc *e) {
 542   int pc;  /* pc of last jump */
 543   luaK_dischargevars(fs, e);
 544   switch (e->k) {
 545     case VK: case VKNUM: case VTRUE: {
 546       pc = NO_JUMP;  /* always true; do nothing */
 547       break;
 548     }
 549     case VJMP: {
 550       invertjump(fs, e);
 551       pc = e->u.s.info;
 552       break;
 553     }
 554     default: {
 555       pc = jumponcond(fs, e, 0);
 556       break;
 557     }
 558   }
 559   luaK_concat(fs, &e->f, pc);  /* insert last jump in `f' list */
 560   luaK_patchtohere(fs, e->t);
 561   e->t = NO_JUMP;
 562 }
 563
 564
 565 static void luaK_goiffalse (FuncState *fs, expdesc *e) {
 566   int pc;  /* pc of last jump */
 567   luaK_dischargevars(fs, e);
 568   switch (e->k) {
 569     case VNIL: case VFALSE: {
 570       pc = NO_JUMP;  /* always false; do nothing */
 571       break;
 572     }
 573     case VJMP: {
 574       pc = e->u.s.info;
 575       break;
 576     }
 577     default: {
 578       pc = jumponcond(fs, e, 1);
 579       break;
 580     }
 581   }
 582   luaK_concat(fs, &e->t, pc);  /* insert last jump in `t' list */
 583   luaK_patchtohere(fs, e->f);
 584   e->f = NO_JUMP;
 585 }
 586
 587
 588 static void codenot (FuncState *fs, expdesc *e) {
 589   luaK_dischargevars(fs, e);
 590   switch (e->k) {
 591     case VNIL: case VFALSE: {
 592       e->k = VTRUE;
 593       break;
 594     }
 595     case VK: case VKNUM: case VTRUE: {
 596       e->k = VFALSE;
 597       break;
 598     }
 599     case VJMP: {
 600       invertjump(fs, e);
 601       break;
 602     }
 603     case VRELOCABLE:
 604     case VNONRELOC: {
 605       discharge2anyreg(fs, e);
 606       freeexp(fs, e);
 607       e->u.s.info = luaK_codeABC(fs, OP_NOT, 0, e->u.s.info, 0);
 608       e->k = VRELOCABLE;
 609       break;
 610     }
 611     default: {
 612       lua_assert(0);  /* cannot happen */
 613       break;
 614     }
 615   }
 616   /* interchange true and false lists */
 617   { int temp = e->f; e->f = e->t; e->t = temp; }
 618   removevalues(fs, e->f);
 619   removevalues(fs, e->t);
 620 }
 621
 622
 623 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
 624   t->u.s.aux = luaK_exp2RK(fs, k);
 625   t->k = VINDEXED;
 626 }
 627
 628
 629 static int constfolding (OpCode op, expdesc *e1, expdesc *e2) {
 630   lua_Number v1, v2, r;
 631   if (!isnumeral(e1) || !isnumeral(e2)) return 0;
 632   v1 = e1->u.nval;
 633   v2 = e2->u.nval;
 634   switch (op) {
 635     case OP_ADD: r = luai_numadd(v1, v2); break;
 636     case OP_SUB: r = luai_numsub(v1, v2); break;
 637     case OP_MUL: r = luai_nummul(v1, v2); break;
 638     case OP_DIV:
 639       if (v2 == 0) return 0;  /* do not attempt to divide by 0 */
 640       r = luai_numdiv(v1, v2); break;
 641     case OP_MOD:
 642       if (v2 == 0) return 0;  /* do not attempt to divide by 0 */
 643       r = luai_nummod(v1, v2); break;
 644     case OP_POW: r = luai_numpow(v1, v2); break;
 645     case OP_UNM: r = luai_numunm(v1); break;
 646     case OP_LEN: return 0;  /* no constant folding for 'len' */
 647     default: lua_assert(0); r = 0; break;
 648   }
 649   if (luai_numisnan(r)) return 0;  /* do not attempt to produce NaN */
 650   e1->u.nval = r;
 651   return 1;
 652 }
 653
 654
 655 static void codearith (FuncState *fs, OpCode op, expdesc *e1, expdesc *e2) {
 656   if (constfolding(op, e1, e2))
 657     return;
 658   else {
 659     int o2 = (op != OP_UNM && op != OP_LEN) ? luaK_exp2RK(fs, e2) : 0;
 660     int o1 = luaK_exp2RK(fs, e1);
 661     if (o1 > o2) {
 662       freeexp(fs, e1);
 663       freeexp(fs, e2);
 664     }
 665     else {
 666       freeexp(fs, e2);
 667       freeexp(fs, e1);
 668     }
 669     e1->u.s.info = luaK_codeABC(fs, op, 0, o1, o2);
 670     e1->k = VRELOCABLE;
 671   }
 672 }
 673
 674
 675 static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,
 676                                                           expdesc *e2) {
 677   int o1 = luaK_exp2RK(fs, e1);
 678   int o2 = luaK_exp2RK(fs, e2);
 679   freeexp(fs, e2);
 680   freeexp(fs, e1);
 681   if (cond == 0 && op != OP_EQ) {
 682     int temp;  /* exchange args to replace by `<' or `<=' */
 683     temp = o1; o1 = o2; o2 = temp;  /* o1 <==> o2 */
 684     cond = 1;
 685   }
 686   e1->u.s.info = condjump(fs, op, cond, o1, o2);
 687   e1->k = VJMP;
 688 }
 689
 690
 691 void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e) {
 692   expdesc e2;
 693   e2.t = e2.f = NO_JUMP; e2.k = VKNUM; e2.u.nval = 0;
 694   switch (op) {
 695     case OPR_MINUS: {
 696       if (!isnumeral(e))
 697         luaK_exp2anyreg(fs, e);  /* cannot operate on non-numeric constants */
 698       codearith(fs, OP_UNM, e, &e2);
 699       break;
 700     }
 701     case OPR_NOT: codenot(fs, e); break;
 702     case OPR_LEN: {
 703       luaK_exp2anyreg(fs, e);  /* cannot operate on constants */
 704       codearith(fs, OP_LEN, e, &e2);
 705       break;
 706     }
 707     default: lua_assert(0);
 708   }
 709 }
 710
 711
 712 void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
 713   switch (op) {
 714     case OPR_AND: {
 715       luaK_goiftrue(fs, v);
 716       break;
 717     }
 718     case OPR_OR: {
 719       luaK_goiffalse(fs, v);
 720       break;
 721     }
 722     case OPR_CONCAT: {
 723       luaK_exp2nextreg(fs, v);  /* operand must be on the `stack' */
 724       break;
 725     }
 726     case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:
 727     case OPR_MOD: case OPR_POW: {
 728       if (!isnumeral(v)) luaK_exp2RK(fs, v);
 729       break;
 730     }
 731     default: {
 732       luaK_exp2RK(fs, v);
 733       break;
 734     }
 735   }
 736 }
 737
 738
 739 void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
 740   switch (op) {
 741     case OPR_AND: {
 742       lua_assert(e1->t == NO_JUMP);  /* list must be closed */
 743       luaK_dischargevars(fs, e2);
 744       luaK_concat(fs, &e2->f, e1->f);
 745       *e1 = *e2;
 746       break;
 747     }
 748     case OPR_OR: {
 749       lua_assert(e1->f == NO_JUMP);  /* list must be closed */
 750       luaK_dischargevars(fs, e2);
 751       luaK_concat(fs, &e2->t, e1->t);
 752       *e1 = *e2;
 753       break;
 754     }
 755     case OPR_CONCAT: {
 756       luaK_exp2val(fs, e2);
 757       if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
 758         lua_assert(e1->u.s.info == GETARG_B(getcode(fs, e2))-1);
 759         freeexp(fs, e1);
 760         SETARG_B(getcode(fs, e2), e1->u.s.info);
 761         e1->k = VRELOCABLE; e1->u.s.info = e2->u.s.info;
 762       }
 763       else {
 764         luaK_exp2nextreg(fs, e2);  /* operand must be on the 'stack' */
 765         codearith(fs, OP_CONCAT, e1, e2);
 766       }
 767       break;
 768     }
 769     case OPR_ADD: codearith(fs, OP_ADD, e1, e2); break;
 770     case OPR_SUB: codearith(fs, OP_SUB, e1, e2); break;
 771     case OPR_MUL: codearith(fs, OP_MUL, e1, e2); break;
 772     case OPR_DIV: codearith(fs, OP_DIV, e1, e2); break;
 773     case OPR_MOD: codearith(fs, OP_MOD, e1, e2); break;
 774     case OPR_POW: codearith(fs, OP_POW, e1, e2); break;
 775     case OPR_EQ: codecomp(fs, OP_EQ, 1, e1, e2); break;
 776     case OPR_NE: codecomp(fs, OP_EQ, 0, e1, e2); break;
 777     case OPR_LT: codecomp(fs, OP_LT, 1, e1, e2); break;
 778     case OPR_LE: codecomp(fs, OP_LE, 1, e1, e2); break;
 779     case OPR_GT: codecomp(fs, OP_LT, 0, e1, e2); break;
 780     case OPR_GE: codecomp(fs, OP_LE, 0, e1, e2); break;
 781     default: lua_assert(0);
 782   }
 783 }
 784
 785
 786 void luaK_fixline (FuncState *fs, int line) {
 787   fs->f->lineinfo[fs->pc - 1] = line;
 788 }
 789
 790
 791 static int luaK_code (FuncState *fs, Instruction i, int line) {
 792   Proto *f = fs->f;
 793   dischargejpc(fs);  /* `pc' will change */
 794   /* put new instruction in code array */
 795   luaM_growvector(fs->L, f->code, fs->pc, f->sizecode, Instruction,
 796                   MAX_INT, "code size overflow");
 797   f->code[fs->pc] = i;
 798   /* save corresponding line information */
 799   luaM_growvector(fs->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
 800                   MAX_INT, "code size overflow");
 801   f->lineinfo[fs->pc] = line;
 802   return fs->pc++;
 803 }
 804
 805
 806 int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
 807   lua_assert(getOpMode(o) == iABC);
 808   lua_assert(getBMode(o) != OpArgN || b == 0);
 809   lua_assert(getCMode(o) != OpArgN || c == 0);
 810   return luaK_code(fs, CREATE_ABC(o, a, b, c), fs->ls->lastline);
 811 }
 812
 813
 814 int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
 815   lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
 816   lua_assert(getCMode(o) == OpArgN);
 817   return luaK_code(fs, CREATE_ABx(o, a, bc), fs->ls->lastline);
 818 }
 819
 820
 821 void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
 822   int c =  (nelems - 1)/LFIELDS_PER_FLUSH + 1;
 823   int b = (tostore == LUA_MULTRET) ? 0 : tostore;
 824   lua_assert(tostore != 0);
 825   if (c <= MAXARG_C)
 826     luaK_codeABC(fs, OP_SETLIST, base, b, c);
 827   else {
 828     luaK_codeABC(fs, OP_SETLIST, base, b, 0);
 829     luaK_code(fs, cast(Instruction, c), fs->ls->lastline);
 830   }
 831   fs->freereg = base + 1;  /* free registers with list values */
 832 }
 833