1 /*

     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

     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 

    26 

    27 #define hasjumps(e)	((e)->t != (e)->f)

    28 

    29 

    30 static int isnumeral(expdesc *e) {

    31   return (e->k == VKNUM && e->t == NO_JUMP && e->f == NO_JUMP);

    32 }

    33 

    34 

    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 */

    41     }

    42     else {

    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? */

    48           if (from+n-1 > pto)

    49             SETARG_B(*previous, from+n-1);

    50           return;

    51         }

    52       }

    53     }

    54   }

    55   luaK_codeABC(fs, OP_LOADNIL, from, from+n-1, 0);  /* else no optimization */

    56 }

    57 

    58 

    59 int luaK_jump (FuncState *fs) {

    60   int jpc = fs->jpc;  /* save list of jumps to here */

    61   int j;

    62   fs->jpc = NO_JUMP;

    63   j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);

    64   luaK_concat(fs, &j, jpc);  /* keep them on hold */

    65   return j;

    66 }

    67 

    68 

    69 void luaK_ret (FuncState *fs, int first, int nret) {

    70   luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);

    71 }

    72 

    73 

    74 static int condjump (FuncState *fs, OpCode op, int A, int B, int C) {

    75   luaK_codeABC(fs, op, A, B, C);

    76   return luaK_jump(fs);

    77 }

    78 

    79 

    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);

    87 }

    88 

    89 

    90 /*

    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).

    93 */

    94 int luaK_getlabel (FuncState *fs) {

    95   fs->lasttarget = fs->pc;

    96   return fs->pc;

    97 }

    98 

    99 

   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 */

   104   else

   105     return (pc+1)+offset;  /* turn offset into absolute position */

   106 }

   107 

   108 

   109 static Instruction *getjumpcontrol (FuncState *fs, int pc) {

   110   Instruction *pi = &fs->f->code[pc];

   111   if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))

   112     return pi-1;

   113   else

   114     return pi;

   115 }

   116 

   117 

   118 /*

   119 ** check whether list has any jump that do not produce a value

   120 ** (or produce an inverted value)

   121 */

   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;

   126   }

   127   return 0;  /* not found */

   128 }

   129 

   130 

   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))

   136     SETARG_A(*i, reg);

   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));

   139 

   140   return 1;

   141 }

   142 

   143 

   144 static void removevalues (FuncState *fs, int list) {

   145   for (; list != NO_JUMP; list = getjump(fs, list))

   146       patchtestreg(fs, list, NO_REG);

   147 }

   148 

   149 

   150 static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,

   151                           int dtarget) {

   152   while (list != NO_JUMP) {

   153     int next = getjump(fs, list);

   154     if (patchtestreg(fs, list, reg))

   155       fixjump(fs, list, vtarget);

   156     else

   157       fixjump(fs, list, dtarget);  /* jump to default target */

   158     list = next;

   159   }

   160 }

   161 

   162 

   163 static void dischargejpc (FuncState *fs) {

   164   patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);

   165   fs->jpc = NO_JUMP;

   166 }

   167 

   168 

   169 void luaK_patchlist (FuncState *fs, int list, int target) {

   170   if (target == fs->pc)

   171     luaK_patchtohere(fs, list);

   172   else {

   173     lua_assert(target < fs->pc);

   174     patchlistaux(fs, list, target, NO_REG, target);

   175   }

   176 }

   177 

   178 

   179 void luaK_patchtohere (FuncState *fs, int list) {

   180   luaK_getlabel(fs);

   181   luaK_concat(fs, &fs->jpc, list);

   182 }

   183 

   184 

   185 void luaK_concat (FuncState *fs, int *l1, int l2) {

   186   if (l2 == NO_JUMP) return;

   187   else if (*l1 == NO_JUMP)

   188     *l1 = l2;

   189   else {

   190     int list = *l1;

   191     int next;

   192     while ((next = getjump(fs, list)) != NO_JUMP)  /* find last element */

   193       list = next;

   194     fixjump(fs, list, l2);

   195   }

   196 }

   197 

   198 

   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);

   205   }

   206 }

   207 

   208 

   209 void luaK_reserveregs (FuncState *fs, int n) {

   210   luaK_checkstack(fs, n);

   211   fs->freereg += n;

   212 }

   213 

   214 

   215 static void freereg (FuncState *fs, int reg) {

   216   if (!ISK(reg) && reg >= fs->nactvar) {

   217     fs->freereg--;

   218     lua_assert(reg == fs->freereg);

   219   }

   220 }

   221 

   222 

   223 static void freeexp (FuncState *fs, expdesc *e) {

   224   if (e->k == VNONRELOC)

   225     freereg(fs, e->u.s.info);

   226 }

   227 

   228 

   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);

   232   Proto *f = fs->f;

   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));

   237   }

   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);

   245     return fs->nk++;

   246   }

   247 }

   248 

   249 

   250 int luaK_stringK (FuncState *fs, TString *s) {

   251   TValue o;

   252   setsvalue(fs->L, &o, s);

   253   return addk(fs, &o, &o);

   254 }

   255 

   256 

   257 int luaK_numberK (FuncState *fs, lua_Number r) {

   258   TValue o;

   259   setnvalue(&o, r);

   260   return addk(fs, &o, &o);

   261 }

   262 

   263 

   264 static int boolK (FuncState *fs, int b) {

   265   TValue o;

   266   setbvalue(&o, b);

   267   return addk(fs, &o, &o);

   268 }

   269 

   270 

   271 static int nilK (FuncState *fs) {

   272   TValue k, v;

   273   setnilvalue(&v);

   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);

   277 }

   278 

   279 

   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);

   283   }

   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);

   288   }

   289 }

   290 

   291 

   292 void luaK_setoneret (FuncState *fs, expdesc *e) {

   293   if (e->k == VCALL) {  /* expression is an open function call? */

   294     e->k = VNONRELOC;

   295     e->u.s.info = GETARG_A(getcode(fs, e));

   296   }

   297   else if (e->k == VVARARG) {

   298     SETARG_B(getcode(fs, e), 2);

   299     e->k = VRELOCABLE;  /* can relocate its simple result */

   300   }

   301 }

   302 

   303 

   304 void luaK_dischargevars (FuncState *fs, expdesc *e) {

   305   switch (e->k) {

   306     case VLOCAL: {

   307       e->k = VNONRELOC;

   308       break;

   309     }

   310     case VUPVAL: {

   311       e->u.s.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.s.info, 0);

   312       e->k = VRELOCABLE;

   313       break;

   314     }

   315     case VGLOBAL: {

   316       e->u.s.info = luaK_codeABx(fs, OP_GETGLOBAL, 0, e->u.s.info);

   317       e->k = VRELOCABLE;

   318       break;

   319     }

   320     case VINDEXED: {

   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);

   324       e->k = VRELOCABLE;

   325       break;

   326     }

   327     case VVARARG:

   328     case VCALL: {

   329       luaK_setoneret(fs, e);

   330       break;

   331     }

   332     default: break;  /* there is one value available (somewhere) */

   333   }

   334 }

   335 

   336 

   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);

   340 }

   341 

   342 

   343 static void discharge2reg (FuncState *fs, expdesc *e, int reg) {

   344   luaK_dischargevars(fs, e);

   345   switch (e->k) {

   346     case VNIL: {

   347       luaK_nil(fs, reg, 1);

   348       break;

   349     }

   350     case VFALSE:  case VTRUE: {

   351       luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);

   352       break;

   353     }

   354     case VK: {

   355       luaK_codeABx(fs, OP_LOADK, reg, e->u.s.info);

   356       break;

   357     }

   358     case VKNUM: {

   359       luaK_codeABx(fs, OP_LOADK, reg, luaK_numberK(fs, e->u.nval));

   360       break;

   361     }

   362     case VRELOCABLE: {

   363       Instruction *pc = &getcode(fs, e);

   364       SETARG_A(*pc, reg);

   365       break;

   366     }

   367     case VNONRELOC: {

   368       if (reg != e->u.s.info)

   369         luaK_codeABC(fs, OP_MOVE, reg, e->u.s.info, 0);

   370       break;

   371     }

   372     default: {

   373       lua_assert(e->k == VVOID || e->k == VJMP);

   374       return;  /* nothing to do... */

   375     }

   376   }

   377   e->u.s.info = reg;

   378   e->k = VNONRELOC;

   379 }

   380 

   381 

   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);

   386   }

   387 }

   388 

   389 

   390 static void exp2reg (FuncState *fs, expdesc *e, int reg) {

   391   discharge2reg(fs, e, reg);

   392   if (e->k == VJMP)

   393     luaK_concat(fs, &e->t, e->u.s.info);  /* put this jump in `t' list */

   394   if (hasjumps(e)) {

   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);

   403     }

   404     final = luaK_getlabel(fs);

   405     patchlistaux(fs, e->f, final, reg, p_f);

   406     patchlistaux(fs, e->t, final, reg, p_t);

   407   }

   408   e->f = e->t = NO_JUMP;

   409   e->u.s.info = reg;

   410   e->k = VNONRELOC;

   411 }

   412 

   413 

   414 void luaK_exp2nextreg (FuncState *fs, expdesc *e) {

   415   luaK_dischargevars(fs, e);

   416   freeexp(fs, e);

   417   luaK_reserveregs(fs, 1);

   418   exp2reg(fs, e, fs->freereg - 1);

   419 }

   420 

   421 

   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 */

   428       return e->u.s.info;

   429     }

   430   }

   431   luaK_exp2nextreg(fs, e);  /* default */

   432   return e->u.s.info;

   433 }

   434 

   435 

   436 void luaK_exp2val (FuncState *fs, expdesc *e) {

   437   if (hasjumps(e))

   438     luaK_exp2anyreg(fs, e);

   439   else

   440     luaK_dischargevars(fs, e);

   441 }

   442 

   443 

   444 int luaK_exp2RK (FuncState *fs, expdesc *e) {

   445   luaK_exp2val(fs, e);

   446   switch (e->k) {

   447     case VKNUM:

   448     case VTRUE:

   449     case VFALSE:

   450     case VNIL: {

   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));

   455         e->k = VK;

   456         return RKASK(e->u.s.info);

   457       }

   458       else break;

   459     }

   460     case VK: {

   461       if (e->u.s.info <= MAXINDEXRK)  /* constant fit in argC? */

   462         return RKASK(e->u.s.info);

   463       else break;

   464     }

   465     default: break;

   466   }

   467   /* not a constant in the right range: put it in a register */

   468   return luaK_exp2anyreg(fs, e);

   469 }

   470 

   471 

   472 void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {

   473   switch (var->k) {

   474     case VLOCAL: {

   475       freeexp(fs, ex);

   476       exp2reg(fs, ex, var->u.s.info);

   477       return;

   478     }

   479     case VUPVAL: {

   480       int e = luaK_exp2anyreg(fs, ex);

   481       luaK_codeABC(fs, OP_SETUPVAL, e, var->u.s.info, 0);

   482       break;

   483     }

   484     case VGLOBAL: {

   485       int e = luaK_exp2anyreg(fs, ex);

   486       luaK_codeABx(fs, OP_SETGLOBAL, e, var->u.s.info);

   487       break;

   488     }

   489     case VINDEXED: {

   490       int e = luaK_exp2RK(fs, ex);

   491       luaK_codeABC(fs, OP_SETTABLE, var->u.s.info, var->u.s.aux, e);

   492       break;

   493     }

   494     default: {

   495       lua_assert(0);  /* invalid var kind to store */

   496       break;

   497     }

   498   }

   499   freeexp(fs, ex);

   500 }

   501 

   502 

   503 void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {

   504   int func;

   505   luaK_exp2anyreg(fs, e);

   506   freeexp(fs, e);

   507   func = fs->freereg;

   508   luaK_reserveregs(fs, 2);

   509   luaK_codeABC(fs, OP_SELF, func, e->u.s.info, luaK_exp2RK(fs, key));

   510   freeexp(fs, key);

   511   e->u.s.info = func;

   512   e->k = VNONRELOC;

   513 }

   514 

   515 

   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)));

   521 }

   522 

   523 

   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);

   530     }

   531     /* else go through */

   532   }

   533   discharge2anyreg(fs, e);

   534   freeexp(fs, e);

   535   return condjump(fs, OP_TESTSET, NO_REG, e->u.s.info, cond);

   536 }

   537 

   538 

   539 void luaK_goiftrue (FuncState *fs, expdesc *e) {

   540   int pc;  /* pc of last jump */

   541   luaK_dischargevars(fs, e);

   542   switch (e->k) {

   543     case VK: case VKNUM: case VTRUE: {

   544       pc = NO_JUMP;  /* always true; do nothing */

   545       break;

   546     }

   547     case VFALSE: {

   548       pc = luaK_jump(fs);  /* always jump */

   549       break;

   550     }

   551     case VJMP: {

   552       invertjump(fs, e);

   553       pc = e->u.s.info;

   554       break;

   555     }

   556     default: {

   557       pc = jumponcond(fs, e, 0);

   558       break;

   559     }

   560   }

   561   luaK_concat(fs, &e->f, pc);  /* insert last jump in `f' list */

   562   luaK_patchtohere(fs, e->t);

   563   e->t = NO_JUMP;

   564 }

   565 

   566 

   567 static void luaK_goiffalse (FuncState *fs, expdesc *e) {

   568   int pc;  /* pc of last jump */

   569   luaK_dischargevars(fs, e);

   570   switch (e->k) {

   571     case VNIL: case VFALSE: {

   572       pc = NO_JUMP;  /* always false; do nothing */

   573       break;

   574     }

   575     case VTRUE: {

   576       pc = luaK_jump(fs);  /* always jump */

   577       break;

   578     }

   579     case VJMP: {

   580       pc = e->u.s.info;

   581       break;

   582     }

   583     default: {

   584       pc = jumponcond(fs, e, 1);

   585       break;

   586     }

   587   }

   588   luaK_concat(fs, &e->t, pc);  /* insert last jump in `t' list */

   589   luaK_patchtohere(fs, e->f);

   590   e->f = NO_JUMP;

   591 }

   592 

   593 

   594 static void codenot (FuncState *fs, expdesc *e) {

   595   luaK_dischargevars(fs, e);

   596   switch (e->k) {

   597     case VNIL: case VFALSE: {

   598       e->k = VTRUE;

   599       break;

   600     }

   601     case VK: case VKNUM: case VTRUE: {

   602       e->k = VFALSE;

   603       break;

   604     }

   605     case VJMP: {

   606       invertjump(fs, e);

   607       break;

   608     }

   609     case VRELOCABLE:

   610     case VNONRELOC: {

   611       discharge2anyreg(fs, e);

   612       freeexp(fs, e);

   613       e->u.s.info = luaK_codeABC(fs, OP_NOT, 0, e->u.s.info, 0);

   614       e->k = VRELOCABLE;

   615       break;

   616     }

   617     default: {

   618       lua_assert(0);  /* cannot happen */

   619       break;

   620     }

   621   }

   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);

   626 }

   627 

   628 

   629 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {

   630   t->u.s.aux = luaK_exp2RK(fs, k);

   631   t->k = VINDEXED;

   632 }

   633 

   634 

   635 static int constfolding (OpCode op, expdesc *e1, expdesc *e2) {

   636   lua_Number v1, v2, r;

   637   if (!isnumeral(e1) || !isnumeral(e2)) return 0;

   638   v1 = e1->u.nval;

   639   v2 = e2->u.nval;

   640   switch (op) {

   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;

   644     case OP_DIV:

   645       if (v2 == 0) return 0;  /* do not attempt to divide by 0 */

   646       r = luai_numdiv(v1, v2); break;

   647     case OP_MOD:

   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;

   654   }

   655   if (luai_numisnan(r)) return 0;  /* do not attempt to produce NaN */

   656   e1->u.nval = r;

   657   return 1;

   658 }

   659 

   660 

   661 static void codearith (FuncState *fs, OpCode op, expdesc *e1, expdesc *e2) {

   662   if (constfolding(op, e1, e2))

   663     return;

   664   else {

   665     int o2 = (op != OP_UNM && op != OP_LEN) ? luaK_exp2RK(fs, e2) : 0;

   666     int o1 = luaK_exp2RK(fs, e1);

   667     if (o1 > o2) {

   668       freeexp(fs, e1);

   669       freeexp(fs, e2);

   670     }

   671     else {

   672       freeexp(fs, e2);

   673       freeexp(fs, e1);

   674     }

   675     e1->u.s.info = luaK_codeABC(fs, op, 0, o1, o2);

   676     e1->k = VRELOCABLE;

   677   }

   678 }

   679 

   680 

   681 static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,

   682                                                           expdesc *e2) {

   683   int o1 = luaK_exp2RK(fs, e1);

   684   int o2 = luaK_exp2RK(fs, e2);

   685   freeexp(fs, e2);

   686   freeexp(fs, e1);

   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 */

   690     cond = 1;

   691   }

   692   e1->u.s.info = condjump(fs, op, cond, o1, o2);

   693   e1->k = VJMP;

   694 }

   695 

   696 

   697 void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e) {

   698   expdesc e2;

   699   e2.t = e2.f = NO_JUMP; e2.k = VKNUM; e2.u.nval = 0;

   700   switch (op) {

   701     case OPR_MINUS: {

   702       if (!isnumeral(e))

   703         luaK_exp2anyreg(fs, e);  /* cannot operate on non-numeric constants */

   704       codearith(fs, OP_UNM, e, &e2);

   705       break;

   706     }

   707     case OPR_NOT: codenot(fs, e); break;

   708     case OPR_LEN: {

   709       luaK_exp2anyreg(fs, e);  /* cannot operate on constants */

   710       codearith(fs, OP_LEN, e, &e2);

   711       break;

   712     }

   713     default: lua_assert(0);

   714   }

   715 }

   716 

   717 

   718 void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {

   719   switch (op) {

   720     case OPR_AND: {

   721       luaK_goiftrue(fs, v);

   722       break;

   723     }

   724     case OPR_OR: {

   725       luaK_goiffalse(fs, v);

   726       break;

   727     }

   728     case OPR_CONCAT: {

   729       luaK_exp2nextreg(fs, v);  /* operand must be on the `stack' */

   730       break;

   731     }

   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);

   735       break;

   736     }

   737     default: {

   738       luaK_exp2RK(fs, v);

   739       break;

   740     }

   741   }

   742 }

   743 

   744 

   745 void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {

   746   switch (op) {

   747     case OPR_AND: {

   748       lua_assert(e1->t == NO_JUMP);  /* list must be closed */

   749       luaK_dischargevars(fs, e2);

   750       luaK_concat(fs, &e2->f, e1->f);

   751       *e1 = *e2;

   752       break;

   753     }

   754     case OPR_OR: {

   755       lua_assert(e1->f == NO_JUMP);  /* list must be closed */

   756       luaK_dischargevars(fs, e2);

   757       luaK_concat(fs, &e2->t, e1->t);

   758       *e1 = *e2;

   759       break;

   760     }

   761     case OPR_CONCAT: {

   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);

   765         freeexp(fs, e1);

   766         SETARG_B(getcode(fs, e2), e1->u.s.info);

   767         e1->k = VRELOCABLE; e1->u.s.info = e2->u.s.info;

   768       }

   769       else {

   770         luaK_exp2nextreg(fs, e2);  /* operand must be on the 'stack' */

   771         codearith(fs, OP_CONCAT, e1, e2);

   772       }

   773       break;

   774     }

   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);

   788   }

   789 }

   790 

   791 

   792 void luaK_fixline (FuncState *fs, int line) {

   793   fs->f->lineinfo[fs->pc - 1] = line;

   794 }

   795 

   796 

   797 static int luaK_code (FuncState *fs, Instruction i, int line) {

   798   Proto *f = fs->f;

   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");

   803   f->code[fs->pc] = i;

   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;

   808   return fs->pc++;

   809 }

   810 

   811 

   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);

   817 }

   818 

   819 

   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);

   824 }

   825 

   826 

   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);

   831   if (c <= MAXARG_C)

   832     luaK_codeABC(fs, OP_SETLIST, base, b, c);

   833   else {

   834     luaK_codeABC(fs, OP_SETLIST, base, b, 0);

   835     luaK_code(fs, cast(Instruction, c), fs->ls->lastline);

   836   }

   837   fs->freereg = base + 1;  /* free registers with list values */

   838 }

   839