/*

 ** $Id: lcode.c,v 2.25.1.3 2007/12/28 15:32:23 roberto Exp $

 ** Code generator for Lua

 ** See Copyright Notice in lua.h

 */

 

 

 #include <stdlib.h>

 

 #define lcode_c

 #define LUA_CORE

 

 #include "lua.h"

 

 #include "lcode.h"

 #include "ldebug.h"

 #include "ldo.h"

 #include "lgc.h"

 #include "llex.h"

 #include "lmem.h"

 #include "lobject.h"

 #include "lopcodes.h"

 #include "lparser.h"

 #include "ltable.h"

 

 

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

 

 

 static int isnumeral(expdesc *e) {

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

 }

 

 

 void luaK_nil (FuncState *fs, int from, int n) {

   Instruction *previous;

   if (fs->pc > fs->lasttarget) {  /* no jumps to current position? */

     if (fs->pc == 0) {  /* function start? */

       if (from >= fs->nactvar)

         return;  /* positions are already clean */

     }

     else {

       previous = &fs->f->code[fs->pc-1];

       if (GET_OPCODE(*previous) == OP_LOADNIL) {

         int pfrom = GETARG_A(*previous);

         int pto = GETARG_B(*previous);

         if (pfrom <= from && from <= pto+1) {  /* can connect both? */

           if (from+n-1 > pto)

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

           return;

         }

       }

     }

   }

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

 }

 

 

 int luaK_jump (FuncState *fs) {

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

   int j;

   fs->jpc = NO_JUMP;

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

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

   return j;

 }

 

 

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

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

 }

 

 

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

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

   return luaK_jump(fs);

 }

 

 

 static void fixjump (FuncState *fs, int pc, int dest) {

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

   int offset = dest-(pc+1);

   lua_assert(dest != NO_JUMP);

   if (abs(offset) > MAXARG_sBx)

     luaX_syntaxerror(fs->ls, "control structure too long");

   SETARG_sBx(*jmp, offset);

 }

 

 

 /*

 ** returns current `pc' and marks it as a jump target (to avoid wrong

 ** optimizations with consecutive instructions not in the same basic block).

 */

 int luaK_getlabel (FuncState *fs) {

   fs->lasttarget = fs->pc;

   return fs->pc;

 }

 

 

 static int getjump (FuncState *fs, int pc) {

   int offset = GETARG_sBx(fs->f->code[pc]);

   if (offset == NO_JUMP)  /* point to itself represents end of list */

     return NO_JUMP;  /* end of list */

   else

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

 }

 

 

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

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

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

     return pi-1;

   else

     return pi;

 }

 

 

 /*

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

 ** (or produce an inverted value)

 */

 static int need_value (FuncState *fs, int list) {

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

     Instruction i = *getjumpcontrol(fs, list);

     if (GET_OPCODE(i) != OP_TESTSET) return 1;

   }

   return 0;  /* not found */

 }

 

 

 static int patchtestreg (FuncState *fs, int node, int reg) {

   Instruction *i = getjumpcontrol(fs, node);

   if (GET_OPCODE(*i) != OP_TESTSET)

     return 0;  /* cannot patch other instructions */

   if (reg != NO_REG && reg != GETARG_B(*i))

     SETARG_A(*i, reg);

   else  /* no register to put value or register already has the value */

     *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));

 

   return 1;

 }

 

 

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

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

       patchtestreg(fs, list, NO_REG);

 }

 

 

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

                           int dtarget) {

   while (list != NO_JUMP) {

     int next = getjump(fs, list);

     if (patchtestreg(fs, list, reg))

       fixjump(fs, list, vtarget);

     else

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

     list = next;

   }

 }

 

 

 static void dischargejpc (FuncState *fs) {

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

   fs->jpc = NO_JUMP;

 }

 

 

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

   if (target == fs->pc)

     luaK_patchtohere(fs, list);

   else {

     lua_assert(target < fs->pc);

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

   }

 }

 

 

 void luaK_patchtohere (FuncState *fs, int list) {

   luaK_getlabel(fs);

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

 }

 

 

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

   if (l2 == NO_JUMP) return;

   else if (*l1 == NO_JUMP)

     *l1 = l2;

   else {

     int list = *l1;

     int next;

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

       list = next;

     fixjump(fs, list, l2);

   }

 }

 

 

 void luaK_checkstack (FuncState *fs, int n) {

   int newstack = fs->freereg + n;

   if (newstack > fs->f->maxstacksize) {

     if (newstack >= MAXSTACK)

       luaX_syntaxerror(fs->ls, "function or expression too complex");

     fs->f->maxstacksize = cast_byte(newstack);

   }

 }

 

 

 void luaK_reserveregs (FuncState *fs, int n) {

   luaK_checkstack(fs, n);

   fs->freereg += n;

 }

 

 

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

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

     fs->freereg--;

     lua_assert(reg == fs->freereg);

   }

 }

 

 

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

   if (e->k == VNONRELOC)

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

 }

 

 

 static int addk (FuncState *fs, TValue *k, TValue *v) {

   lua_State *L = fs->L;

   TValue *idx = luaH_set(L, fs->h, k);

   Proto *f = fs->f;

   int oldsize = f->sizek;

   if (ttisnumber(idx)) {

     lua_assert(luaO_rawequalObj(&fs->f->k[cast_int(nvalue(idx))], v));

     return cast_int(nvalue(idx));

   }

   else {  /* constant not found; create a new entry */

     setnvalue(idx, cast_num(fs->nk));

     luaM_growvector(L, f->k, fs->nk, f->sizek, TValue,

                     MAXARG_Bx, "constant table overflow");

     while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);

     setobj(L, &f->k[fs->nk], v);

     luaC_barrier(L, f, v);

     return fs->nk++;

   }

 }

 

 

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

   TValue o;

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

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

 }

 

 

 int luaK_numberK (FuncState *fs, lua_Number r) {

   TValue o;

   setnvalue(&o, r);

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

 }

 

 

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

   TValue o;

   setbvalue(&o, b);

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

 }

 

 

 static int nilK (FuncState *fs) {

   TValue k, v;

   setnilvalue(&v);

   /* cannot use nil as key; instead use table itself to represent nil */

   sethvalue(fs->L, &k, fs->h);

   return addk(fs, &k, &v);

 }

 

 

 void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {

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

     SETARG_C(getcode(fs, e), nresults+1);

   }

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

     SETARG_B(getcode(fs, e), nresults+1);

     SETARG_A(getcode(fs, e), fs->freereg);

     luaK_reserveregs(fs, 1);

   }

 }

 

 

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

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

     e->k = VNONRELOC;

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

   }

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

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

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

   }

 }

 

 

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

   switch (e->k) {

     case VLOCAL: {

       e->k = VNONRELOC;

       break;

     }

     case VUPVAL: {

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

       e->k = VRELOCABLE;

       break;

     }

     case VGLOBAL: {

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

       e->k = VRELOCABLE;

       break;

     }

     case VINDEXED: {

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

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

       e->u.s.info = luaK_codeABC(fs, OP_GETTABLE, 0, e->u.s.info, e->u.s.aux);

       e->k = VRELOCABLE;

       break;

     }

     case VVARARG:

     case VCALL: {

       luaK_setoneret(fs, e);

       break;

     }

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

   }

 }

 

 

 static int code_label (FuncState *fs, int A, int b, int jump) {

   luaK_getlabel(fs);  /* those instructions may be jump targets */

   return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);

 }

 

 

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

   luaK_dischargevars(fs, e);

   switch (e->k) {

     case VNIL: {

       luaK_nil(fs, reg, 1);

       break;

     }

     case VFALSE:  case VTRUE: {

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

       break;

     }

     case VK: {

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

       break;

     }

     case VKNUM: {

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

       break;

     }

     case VRELOCABLE: {

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

       SETARG_A(*pc, reg);

       break;

     }

     case VNONRELOC: {

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

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

       break;

     }

     default: {

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

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

     }

   }

   e->u.s.info = reg;

   e->k = VNONRELOC;

 }

 

 

 static void discharge2anyreg (FuncState *fs, expdesc *e) {

   if (e->k != VNONRELOC) {

     luaK_reserveregs(fs, 1);

     discharge2reg(fs, e, fs->freereg-1);

   }

 }

 

 

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

   discharge2reg(fs, e, reg);

   if (e->k == VJMP)

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

   if (hasjumps(e)) {

     int final;  /* position after whole expression */

     int p_f = NO_JUMP;  /* position of an eventual LOAD false */

     int p_t = NO_JUMP;  /* position of an eventual LOAD true */

     if (need_value(fs, e->t) || need_value(fs, e->f)) {

       int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);

       p_f = code_label(fs, reg, 0, 1);

       p_t = code_label(fs, reg, 1, 0);

       luaK_patchtohere(fs, fj);

     }

     final = luaK_getlabel(fs);

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

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

   }

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

   e->u.s.info = reg;

   e->k = VNONRELOC;

 }

 

 

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

   luaK_dischargevars(fs, e);

   freeexp(fs, e);

   luaK_reserveregs(fs, 1);

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

 }

 

 

 int luaK_exp2anyreg (FuncState *fs, expdesc *e) {

   luaK_dischargevars(fs, e);

   if (e->k == VNONRELOC) {

     if (!hasjumps(e)) return e->u.s.info;  /* exp is already in a register */

     if (e->u.s.info >= fs->nactvar) {  /* reg. is not a local? */

       exp2reg(fs, e, e->u.s.info);  /* put value on it */

       return e->u.s.info;

     }

   }

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

   return e->u.s.info;

 }

 

 

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

   if (hasjumps(e))

     luaK_exp2anyreg(fs, e);

   else

     luaK_dischargevars(fs, e);

 }

 

 

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

   luaK_exp2val(fs, e);

   switch (e->k) {

     case VKNUM:

     case VTRUE:

     case VFALSE:

     case VNIL: {

       if (fs->nk <= MAXINDEXRK) {  /* constant fit in RK operand? */

         e->u.s.info = (e->k == VNIL)  ? nilK(fs) :

                       (e->k == VKNUM) ? luaK_numberK(fs, e->u.nval) :

                                         boolK(fs, (e->k == VTRUE));

         e->k = VK;

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

       }

       else break;

     }

     case VK: {

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

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

       else break;

     }

     default: break;

   }

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

   return luaK_exp2anyreg(fs, e);

 }

 

 

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

   switch (var->k) {

     case VLOCAL: {

       freeexp(fs, ex);

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

       return;

     }

     case VUPVAL: {

       int e = luaK_exp2anyreg(fs, ex);

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

       break;

     }

     case VGLOBAL: {

       int e = luaK_exp2anyreg(fs, ex);

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

       break;

     }

     case VINDEXED: {

       int e = luaK_exp2RK(fs, ex);

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

       break;

     }

     default: {

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

       break;

     }

   }

   freeexp(fs, ex);

 }

 

 

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

   int func;

   luaK_exp2anyreg(fs, e);

   freeexp(fs, e);

   func = fs->freereg;

   luaK_reserveregs(fs, 2);

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

   freeexp(fs, key);

   e->u.s.info = func;

   e->k = VNONRELOC;

 }

 

 

 static void invertjump (FuncState *fs, expdesc *e) {

   Instruction *pc = getjumpcontrol(fs, e->u.s.info);

   lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&

                                            GET_OPCODE(*pc) != OP_TEST);

   SETARG_A(*pc, !(GETARG_A(*pc)));

 }

 

 

 static int jumponcond (FuncState *fs, expdesc *e, int cond) {

   if (e->k == VRELOCABLE) {

     Instruction ie = getcode(fs, e);

     if (GET_OPCODE(ie) == OP_NOT) {

       fs->pc--;  /* remove previous OP_NOT */

       return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);

     }

     /* else go through */

   }

   discharge2anyreg(fs, e);

   freeexp(fs, e);

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

 }

 

 

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

   int pc;  /* pc of last jump */

   luaK_dischargevars(fs, e);

   switch (e->k) {

     case VK: case VKNUM: case VTRUE: {

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

       break;

     }

     case VFALSE: {

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

       break;

     }

     case VJMP: {

       invertjump(fs, e);

       pc = e->u.s.info;

       break;

     }

     default: {

       pc = jumponcond(fs, e, 0);

       break;

     }

   }

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

   luaK_patchtohere(fs, e->t);

   e->t = NO_JUMP;

 }

 

 

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

   int pc;  /* pc of last jump */

   luaK_dischargevars(fs, e);

   switch (e->k) {

     case VNIL: case VFALSE: {

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

       break;

     }

     case VTRUE: {

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

       break;

     }

     case VJMP: {

       pc = e->u.s.info;

       break;

     }

     default: {

       pc = jumponcond(fs, e, 1);

       break;

     }

   }

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

   luaK_patchtohere(fs, e->f);

   e->f = NO_JUMP;

 }

 

 

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

   luaK_dischargevars(fs, e);

   switch (e->k) {

     case VNIL: case VFALSE: {

       e->k = VTRUE;

       break;

     }

     case VK: case VKNUM: case VTRUE: {

       e->k = VFALSE;

       break;

     }

     case VJMP: {

       invertjump(fs, e);

       break;

     }

     case VRELOCABLE:

     case VNONRELOC: {

       discharge2anyreg(fs, e);

       freeexp(fs, e);

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

       e->k = VRELOCABLE;

       break;

     }

     default: {

       lua_assert(0);  /* cannot happen */

       break;

     }

   }

   /* interchange true and false lists */

   { int temp = e->f; e->f = e->t; e->t = temp; }

   removevalues(fs, e->f);

   removevalues(fs, e->t);

 }

 

 

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

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

   t->k = VINDEXED;

 }

 

 

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

   lua_Number v1, v2, r;

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

   v1 = e1->u.nval;

   v2 = e2->u.nval;

   switch (op) {

     case OP_ADD: r = luai_numadd(v1, v2); break;

     case OP_SUB: r = luai_numsub(v1, v2); break;

     case OP_MUL: r = luai_nummul(v1, v2); break;

     case OP_DIV:

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

       r = luai_numdiv(v1, v2); break;

     case OP_MOD:

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

       r = luai_nummod(v1, v2); break;

     case OP_POW: r = luai_numpow(v1, v2); break;

     case OP_UNM: r = luai_numunm(v1); break;

     case OP_LEN: return 0;  /* no constant folding for 'len' */

     default: lua_assert(0); r = 0; break;

   }

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

   e1->u.nval = r;

   return 1;

 }

 

 

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

   if (constfolding(op, e1, e2))

     return;

   else {

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

     int o1 = luaK_exp2RK(fs, e1);

     if (o1 > o2) {

       freeexp(fs, e1);

       freeexp(fs, e2);

     }

     else {

       freeexp(fs, e2);

       freeexp(fs, e1);

     }

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

     e1->k = VRELOCABLE;

   }

 }

 

 

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

                                                           expdesc *e2) {

   int o1 = luaK_exp2RK(fs, e1);

   int o2 = luaK_exp2RK(fs, e2);

   freeexp(fs, e2);

   freeexp(fs, e1);

   if (cond == 0 && op != OP_EQ) {

     int temp;  /* exchange args to replace by `<' or `<=' */

     temp = o1; o1 = o2; o2 = temp;  /* o1 <==> o2 */

     cond = 1;

   }

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

   e1->k = VJMP;

 }

 

 

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

   expdesc e2;

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

   switch (op) {

     case OPR_MINUS: {

       if (!isnumeral(e))

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

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

       break;

     }

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

     case OPR_LEN: {

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

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

       break;

     }

     default: lua_assert(0);

   }

 }

 

 

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

   switch (op) {

     case OPR_AND: {

       luaK_goiftrue(fs, v);

       break;

     }

     case OPR_OR: {

       luaK_goiffalse(fs, v);

       break;

     }

     case OPR_CONCAT: {

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

       break;

     }

     case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:

     case OPR_MOD: case OPR_POW: {

       if (!isnumeral(v)) luaK_exp2RK(fs, v);

       break;

     }

     default: {

       luaK_exp2RK(fs, v);

       break;

     }

   }

 }

 

 

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

   switch (op) {

     case OPR_AND: {

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

       luaK_dischargevars(fs, e2);

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

       *e1 = *e2;

       break;

     }

     case OPR_OR: {

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

       luaK_dischargevars(fs, e2);

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

       *e1 = *e2;

       break;

     }

     case OPR_CONCAT: {

       luaK_exp2val(fs, e2);

       if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {

         lua_assert(e1->u.s.info == GETARG_B(getcode(fs, e2))-1);

         freeexp(fs, e1);

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

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

       }

       else {

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

         codearith(fs, OP_CONCAT, e1, e2);

       }

       break;

     }

     case OPR_ADD: codearith(fs, OP_ADD, e1, e2); break;

     case OPR_SUB: codearith(fs, OP_SUB, e1, e2); break;

     case OPR_MUL: codearith(fs, OP_MUL, e1, e2); break;

     case OPR_DIV: codearith(fs, OP_DIV, e1, e2); break;

     case OPR_MOD: codearith(fs, OP_MOD, e1, e2); break;

     case OPR_POW: codearith(fs, OP_POW, e1, e2); break;

     case OPR_EQ: codecomp(fs, OP_EQ, 1, e1, e2); break;

     case OPR_NE: codecomp(fs, OP_EQ, 0, e1, e2); break;

     case OPR_LT: codecomp(fs, OP_LT, 1, e1, e2); break;

     case OPR_LE: codecomp(fs, OP_LE, 1, e1, e2); break;

     case OPR_GT: codecomp(fs, OP_LT, 0, e1, e2); break;

     case OPR_GE: codecomp(fs, OP_LE, 0, e1, e2); break;

     default: lua_assert(0);

   }

 }

 

 

 void luaK_fixline (FuncState *fs, int line) {

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

 }

 

 

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

   Proto *f = fs->f;

   dischargejpc(fs);  /* `pc' will change */

   /* put new instruction in code array */

   luaM_growvector(fs->L, f->code, fs->pc, f->sizecode, Instruction,

                   MAX_INT, "code size overflow");

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

   /* save corresponding line information */

   luaM_growvector(fs->L, f->lineinfo, fs->pc, f->sizelineinfo, int,

                   MAX_INT, "code size overflow");

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

   return fs->pc++;

 }

 

 

 int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {

   lua_assert(getOpMode(o) == iABC);

   lua_assert(getBMode(o) != OpArgN || b == 0);

   lua_assert(getCMode(o) != OpArgN || c == 0);

   return luaK_code(fs, CREATE_ABC(o, a, b, c), fs->ls->lastline);

 }

 

 

 int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {

   lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);

   lua_assert(getCMode(o) == OpArgN);

   return luaK_code(fs, CREATE_ABx(o, a, bc), fs->ls->lastline);

 }

 

 

 void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {

   int c =  (nelems - 1)/LFIELDS_PER_FLUSH + 1;

   int b = (tostore == LUA_MULTRET) ? 0 : tostore;

   lua_assert(tostore != 0);

   if (c <= MAXARG_C)

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

   else {

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

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

   }

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

 }