lcode.c
上传用户:dzyhzl
上传日期:2019-04-29
资源大小:56270k
文件大小:20k
- /*
- ** $Id: lcode.c,v 1.51 2000/09/29 12:42:13 roberto Exp $
- ** Code generator for Lua
- ** See Copyright Notice in lua.h
- */
- #include "stdlib.h"
- #include "lua.h"
- #include "lcode.h"
- #include "ldo.h"
- #include "llex.h"
- #include "lmem.h"
- #include "lobject.h"
- #include "lopcodes.h"
- #include "lparser.h"
- void luaK_error (LexState *ls, const char *msg) {
- luaX_error(ls, msg, ls->t.token);
- }
- /*
- ** Returns the the previous instruction, for optimizations.
- ** If there is a jump target between this and the current instruction,
- ** returns a dummy instruction to avoid wrong optimizations.
- */
- static Instruction previous_instruction (FuncState *fs) {
- if (fs->pc > fs->lasttarget) /* no jumps to current position? */
- return fs->f->code[fs->pc-1]; /* returns previous instruction */
- else
- return CREATE_0(OP_END); /* no optimizations after an `END' */
- }
- int luaK_jump (FuncState *fs) {
- int j = luaK_code1(fs, OP_JMP, NO_JUMP);
- if (j == fs->lasttarget) { /* possible jumps to this jump? */
- luaK_concat(fs, &j, fs->jlt); /* keep them on hold */
- fs->jlt = NO_JUMP;
- }
- return j;
- }
- static void luaK_fixjump (FuncState *fs, int pc, int dest) {
- Instruction *jmp = &fs->f->code[pc];
- if (dest == NO_JUMP)
- SETARG_S(*jmp, NO_JUMP); /* point to itself to represent end of list */
- else { /* jump is relative to position following jump instruction */
- int offset = dest-(pc+1);
- if (abs(offset) > MAXARG_S)
- luaK_error(fs->ls, "control structure too long");
- SETARG_S(*jmp, offset);
- }
- }
- static int luaK_getjump (FuncState *fs, int pc) {
- int offset = GETARG_S(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 */
- }
- /*
- ** returns current `pc' and marks it as a jump target (to avoid wrong
- ** optimizations with consecutive instructions not in the same basic block).
- ** discharge list of jumps to last target.
- */
- int luaK_getlabel (FuncState *fs) {
- if (fs->pc != fs->lasttarget) {
- int lasttarget = fs->lasttarget;
- fs->lasttarget = fs->pc;
- luaK_patchlist(fs, fs->jlt, lasttarget); /* discharge old list `jlt' */
- fs->jlt = NO_JUMP; /* nobody jumps to this new label (yet) */
- }
- return fs->pc;
- }
- void luaK_deltastack (FuncState *fs, int delta) {
- fs->stacklevel += delta;
- if (fs->stacklevel > fs->f->maxstacksize) {
- if (fs->stacklevel > MAXSTACK)
- luaK_error(fs->ls, "function or expression too complex");
- fs->f->maxstacksize = fs->stacklevel;
- }
- }
- void luaK_kstr (LexState *ls, int c) {
- luaK_code1(ls->fs, OP_PUSHSTRING, c);
- }
- static int number_constant (FuncState *fs, Number r) {
- /* check whether `r' has appeared within the last LOOKBACKNUMS entries */
- Proto *f = fs->f;
- int c = f->nknum;
- int lim = c < LOOKBACKNUMS ? 0 : c-LOOKBACKNUMS;
- while (--c >= lim)
- if (f->knum[c] == r) return c;
- /* not found; create a new entry */
- luaM_growvector(fs->L, f->knum, f->nknum, 1, Number,
- "constant table overflow", MAXARG_U);
- c = f->nknum++;
- f->knum[c] = r;
- return c;
- }
- void luaK_number (FuncState *fs, Number f) {
- if (f <= (Number)MAXARG_S && (Number)(int)f == f)
- luaK_code1(fs, OP_PUSHINT, (int)f); /* f has a short integer value */
- else
- luaK_code1(fs, OP_PUSHNUM, number_constant(fs, f));
- }
- void luaK_adjuststack (FuncState *fs, int n) {
- if (n > 0)
- luaK_code1(fs, OP_POP, n);
- else
- luaK_code1(fs, OP_PUSHNIL, -n);
- }
- int luaK_lastisopen (FuncState *fs) {
- /* check whether last instruction is an open function call */
- Instruction i = previous_instruction(fs);
- if (GET_OPCODE(i) == OP_CALL && GETARG_B(i) == MULT_RET)
- return 1;
- else return 0;
- }
- void luaK_setcallreturns (FuncState *fs, int nresults) {
- if (luaK_lastisopen(fs)) { /* expression is an open function call? */
- SETARG_B(fs->f->code[fs->pc-1], nresults); /* set number of results */
- luaK_deltastack(fs, nresults); /* push results */
- }
- }
- static int discharge (FuncState *fs, expdesc *var) {
- switch (var->k) {
- case VLOCAL:
- luaK_code1(fs, OP_GETLOCAL, var->u.index);
- break;
- case VGLOBAL:
- luaK_code1(fs, OP_GETGLOBAL, var->u.index);
- break;
- case VINDEXED:
- luaK_code0(fs, OP_GETTABLE);
- break;
- case VEXP:
- return 0; /* nothing to do */
- }
- var->k = VEXP;
- var->u.l.t = var->u.l.f = NO_JUMP;
- return 1;
- }
- static void discharge1 (FuncState *fs, expdesc *var) {
- discharge(fs, var);
- /* if it has jumps then it is already discharged */
- if (var->u.l.t == NO_JUMP && var->u.l.f == NO_JUMP)
- luaK_setcallreturns(fs, 1); /* call must return 1 value */
- }
- void luaK_storevar (LexState *ls, const expdesc *var) {
- FuncState *fs = ls->fs;
- switch (var->k) {
- case VLOCAL:
- luaK_code1(fs, OP_SETLOCAL, var->u.index);
- break;
- case VGLOBAL:
- luaK_code1(fs, OP_SETGLOBAL, var->u.index);
- break;
- case VINDEXED: /* table is at top-3; pop 3 elements after operation */
- luaK_code2(fs, OP_SETTABLE, 3, 3);
- break;
- default:
- LUA_INTERNALERROR("invalid var kind to store");
- }
- }
- static OpCode invertjump (OpCode op) {
- switch (op) {
- case OP_JMPNE: return OP_JMPEQ;
- case OP_JMPEQ: return OP_JMPNE;
- case OP_JMPLT: return OP_JMPGE;
- case OP_JMPLE: return OP_JMPGT;
- case OP_JMPGT: return OP_JMPLE;
- case OP_JMPGE: return OP_JMPLT;
- case OP_JMPT: case OP_JMPONT: return OP_JMPF;
- case OP_JMPF: case OP_JMPONF: return OP_JMPT;
- default:
- LUA_INTERNALERROR("invalid jump instruction");
- return OP_END; /* to avoid warnings */
- }
- }
- static void luaK_patchlistaux (FuncState *fs, int list, int target,
- OpCode special, int special_target) {
- Instruction *code = fs->f->code;
- while (list != NO_JUMP) {
- int next = luaK_getjump(fs, list);
- Instruction *i = &code[list];
- OpCode op = GET_OPCODE(*i);
- if (op == special) /* this `op' already has a value */
- luaK_fixjump(fs, list, special_target);
- else {
- luaK_fixjump(fs, list, target); /* do the patch */
- if (op == OP_JMPONT) /* remove eventual values */
- SET_OPCODE(*i, OP_JMPT);
- else if (op == OP_JMPONF)
- SET_OPCODE(*i, OP_JMPF);
- }
- list = next;
- }
- }
- void luaK_patchlist (FuncState *fs, int list, int target) {
- if (target == fs->lasttarget) /* same target that list `jlt'? */
- luaK_concat(fs, &fs->jlt, list); /* delay fixing */
- else
- luaK_patchlistaux(fs, list, target, OP_END, 0);
- }
- static int need_value (FuncState *fs, int list, OpCode hasvalue) {
- /* check whether list has a jump without a value */
- for (; list != NO_JUMP; list = luaK_getjump(fs, list))
- if (GET_OPCODE(fs->f->code[list]) != hasvalue) return 1;
- return 0; /* not found */
- }
- void luaK_concat (FuncState *fs, int *l1, int l2) {
- if (*l1 == NO_JUMP)
- *l1 = l2;
- else {
- int list = *l1;
- for (;;) { /* traverse `l1' */
- int next = luaK_getjump(fs, list);
- if (next == NO_JUMP) { /* end of list? */
- luaK_fixjump(fs, list, l2);
- return;
- }
- list = next;
- }
- }
- }
- static void luaK_testgo (FuncState *fs, expdesc *v, int invert, OpCode jump) {
- int prevpos; /* position of last instruction */
- Instruction *previous;
- int *golist, *exitlist;
- if (!invert) {
- golist = &v->u.l.f; /* go if false */
- exitlist = &v->u.l.t; /* exit if true */
- }
- else {
- golist = &v->u.l.t; /* go if true */
- exitlist = &v->u.l.f; /* exit if false */
- }
- discharge1(fs, v);
- prevpos = fs->pc-1;
- previous = &fs->f->code[prevpos];
- LUA_ASSERT(*previous==previous_instruction(fs), "no jump allowed here");
- if (!ISJUMP(GET_OPCODE(*previous)))
- prevpos = luaK_code1(fs, jump, NO_JUMP);
- else { /* last instruction is already a jump */
- if (invert)
- SET_OPCODE(*previous, invertjump(GET_OPCODE(*previous)));
- }
- luaK_concat(fs, exitlist, prevpos); /* insert last jump in `exitlist' */
- luaK_patchlist(fs, *golist, luaK_getlabel(fs));
- *golist = NO_JUMP;
- }
- void luaK_goiftrue (FuncState *fs, expdesc *v, int keepvalue) {
- luaK_testgo(fs, v, 1, keepvalue ? OP_JMPONF : OP_JMPF);
- }
- static void luaK_goiffalse (FuncState *fs, expdesc *v, int keepvalue) {
- luaK_testgo(fs, v, 0, keepvalue ? OP_JMPONT : OP_JMPT);
- }
- static int code_label (FuncState *fs, OpCode op, int arg) {
- luaK_getlabel(fs); /* those instructions may be jump targets */
- return luaK_code1(fs, op, arg);
- }
- void luaK_tostack (LexState *ls, expdesc *v, int onlyone) {
- FuncState *fs = ls->fs;
- if (!discharge(fs, v)) { /* `v' is an expression? */
- OpCode previous = GET_OPCODE(fs->f->code[fs->pc-1]);
- if (!ISJUMP(previous) && v->u.l.f == NO_JUMP && v->u.l.t == NO_JUMP) {
- /* expression has no jumps */
- if (onlyone)
- luaK_setcallreturns(fs, 1); /* call must return 1 value */
- }
- else { /* expression has jumps */
- int final; /* position after whole expression */
- int j = NO_JUMP; /* eventual jump over values */
- int p_nil = NO_JUMP; /* position of an eventual PUSHNIL */
- int p_1 = NO_JUMP; /* position of an eventual PUSHINT */
- if (ISJUMP(previous) || need_value(fs, v->u.l.f, OP_JMPONF)
- || need_value(fs, v->u.l.t, OP_JMPONT)) {
- /* expression needs values */
- if (ISJUMP(previous))
- luaK_concat(fs, &v->u.l.t, fs->pc-1); /* put `previous' in t. list */
- else {
- j = code_label(fs, OP_JMP, NO_JUMP); /* to jump over both pushes */
- /* correct stack for compiler and symbolic execution */
- luaK_adjuststack(fs, 1);
- }
- p_nil = code_label(fs, OP_PUSHNILJMP, 0);
- p_1 = code_label(fs, OP_PUSHINT, 1);
- luaK_patchlist(fs, j, luaK_getlabel(fs));
- }
- final = luaK_getlabel(fs);
- luaK_patchlistaux(fs, v->u.l.f, p_nil, OP_JMPONF, final);
- luaK_patchlistaux(fs, v->u.l.t, p_1, OP_JMPONT, final);
- v->u.l.f = v->u.l.t = NO_JUMP;
- }
- }
- }
- void luaK_prefix (LexState *ls, UnOpr op, expdesc *v) {
- FuncState *fs = ls->fs;
- if (op == OPR_MINUS) {
- luaK_tostack(ls, v, 1);
- luaK_code0(fs, OP_MINUS);
- }
- else { /* op == NOT */
- Instruction *previous;
- discharge1(fs, v);
- previous = &fs->f->code[fs->pc-1];
- if (ISJUMP(GET_OPCODE(*previous)))
- SET_OPCODE(*previous, invertjump(GET_OPCODE(*previous)));
- else
- luaK_code0(fs, OP_NOT);
- /* interchange true and false lists */
- { int temp = v->u.l.f; v->u.l.f = v->u.l.t; v->u.l.t = temp; }
- }
- }
- void luaK_infix (LexState *ls, BinOpr op, expdesc *v) {
- FuncState *fs = ls->fs;
- switch (op) {
- case OPR_AND:
- luaK_goiftrue(fs, v, 1);
- break;
- case OPR_OR:
- luaK_goiffalse(fs, v, 1);
- break;
- default:
- luaK_tostack(ls, v, 1); /* all other binary operators need a value */
- }
- }
- static const struct {
- OpCode opcode; /* opcode for each binary operator */
- int arg; /* default argument for the opcode */
- } codes[] = { /* ORDER OPR */
- {OP_ADD, 0}, {OP_SUB, 0}, {OP_MULT, 0}, {OP_DIV, 0},
- {OP_POW, 0}, {OP_CONCAT, 2},
- {OP_JMPNE, NO_JUMP}, {OP_JMPEQ, NO_JUMP},
- {OP_JMPLT, NO_JUMP}, {OP_JMPLE, NO_JUMP},
- {OP_JMPGT, NO_JUMP}, {OP_JMPGE, NO_JUMP}
- };
- void luaK_posfix (LexState *ls, BinOpr op, expdesc *v1, expdesc *v2) {
- FuncState *fs = ls->fs;
- switch (op) {
- case OPR_AND: {
- LUA_ASSERT(v1->u.l.t == NO_JUMP, "list must be closed");
- discharge1(fs, v2);
- v1->u.l.t = v2->u.l.t;
- luaK_concat(fs, &v1->u.l.f, v2->u.l.f);
- break;
- }
- case OPR_OR: {
- LUA_ASSERT(v1->u.l.f == NO_JUMP, "list must be closed");
- discharge1(fs, v2);
- v1->u.l.f = v2->u.l.f;
- luaK_concat(fs, &v1->u.l.t, v2->u.l.t);
- break;
- }
- default: {
- luaK_tostack(ls, v2, 1); /* `v2' must be a value */
- luaK_code1(fs, codes[op].opcode, codes[op].arg);
- }
- }
- }
- static void codelineinfo (FuncState *fs) {
- Proto *f = fs->f;
- LexState *ls = fs->ls;
- if (ls->lastline > fs->lastline) {
- luaM_growvector(fs->L, f->lineinfo, f->nlineinfo, 2, int,
- "line info overflow", MAX_INT);
- if (ls->lastline > fs->lastline+1)
- f->lineinfo[f->nlineinfo++] = -(ls->lastline - (fs->lastline+1));
- f->lineinfo[f->nlineinfo++] = fs->pc;
- fs->lastline = ls->lastline;
- }
- }
- int luaK_code0 (FuncState *fs, OpCode o) {
- return luaK_code2(fs, o, 0, 0);
- }
- int luaK_code1 (FuncState *fs, OpCode o, int arg1) {
- return luaK_code2(fs, o, arg1, 0);
- }
- int luaK_code2 (FuncState *fs, OpCode o, int arg1, int arg2) {
- Instruction i = previous_instruction(fs);
- int delta = luaK_opproperties[o].push - luaK_opproperties[o].pop;
- int optm = 0; /* 1 when there is an optimization */
- switch (o) {
- case OP_CLOSURE: {
- delta = -arg2+1;
- break;
- }
- case OP_SETTABLE: {
- delta = -arg2;
- break;
- }
- case OP_SETLIST: {
- if (arg2 == 0) return NO_JUMP; /* nothing to do */
- delta = -arg2;
- break;
- }
- case OP_SETMAP: {
- if (arg1 == 0) return NO_JUMP; /* nothing to do */
- delta = -2*arg1;
- break;
- }
- case OP_RETURN: {
- if (GET_OPCODE(i) == OP_CALL && GETARG_B(i) == MULT_RET) {
- SET_OPCODE(i, OP_TAILCALL);
- SETARG_B(i, arg1);
- optm = 1;
- }
- break;
- }
- case OP_PUSHNIL: {
- if (arg1 == 0) return NO_JUMP; /* nothing to do */
- delta = arg1;
- switch(GET_OPCODE(i)) {
- case OP_PUSHNIL: SETARG_U(i, GETARG_U(i)+arg1); optm = 1; break;
- default: break;
- }
- break;
- }
- case OP_POP: {
- if (arg1 == 0) return NO_JUMP; /* nothing to do */
- delta = -arg1;
- switch(GET_OPCODE(i)) {
- case OP_SETTABLE: SETARG_B(i, GETARG_B(i)+arg1); optm = 1; break;
- default: break;
- }
- break;
- }
- case OP_GETTABLE: {
- switch(GET_OPCODE(i)) {
- case OP_PUSHSTRING: /* `t.x' */
- SET_OPCODE(i, OP_GETDOTTED);
- optm = 1;
- break;
- case OP_GETLOCAL: /* `t[i]' */
- SET_OPCODE(i, OP_GETINDEXED);
- optm = 1;
- break;
- default: break;
- }
- break;
- }
- case OP_ADD: {
- switch(GET_OPCODE(i)) {
- case OP_PUSHINT: SET_OPCODE(i, OP_ADDI); optm = 1; break; /* `a+k' */
- default: break;
- }
- break;
- }
- case OP_SUB: {
- switch(GET_OPCODE(i)) {
- case OP_PUSHINT: /* `a-k' */
- i = CREATE_S(OP_ADDI, -GETARG_S(i));
- optm = 1;
- break;
- default: break;
- }
- break;
- }
- case OP_CONCAT: {
- delta = -arg1+1;
- switch(GET_OPCODE(i)) {
- case OP_CONCAT: /* `a..b..c' */
- SETARG_U(i, GETARG_U(i)+1);
- optm = 1;
- break;
- default: break;
- }
- break;
- }
- case OP_MINUS: {
- switch(GET_OPCODE(i)) {
- case OP_PUSHINT: /* `-k' */
- SETARG_S(i, -GETARG_S(i));
- optm = 1;
- break;
- case OP_PUSHNUM: /* `-k' */
- SET_OPCODE(i, OP_PUSHNEGNUM);
- optm = 1;
- break;
- default: break;
- }
- break;
- }
- case OP_JMPNE: {
- if (i == CREATE_U(OP_PUSHNIL, 1)) { /* `a~=nil' */
- i = CREATE_S(OP_JMPT, NO_JUMP);
- optm = 1;
- }
- break;
- }
- case OP_JMPEQ: {
- if (i == CREATE_U(OP_PUSHNIL, 1)) { /* `a==nil' */
- i = CREATE_0(OP_NOT);
- delta = -1; /* just undo effect of previous PUSHNIL */
- optm = 1;
- }
- break;
- }
- case OP_JMPT:
- case OP_JMPONT: {
- switch (GET_OPCODE(i)) {
- case OP_NOT: {
- i = CREATE_S(OP_JMPF, NO_JUMP);
- optm = 1;
- break;
- }
- case OP_PUSHINT: {
- if (o == OP_JMPT) { /* JMPONT must keep original integer value */
- i = CREATE_S(OP_JMP, NO_JUMP);
- optm = 1;
- }
- break;
- }
- case OP_PUSHNIL: {
- if (GETARG_U(i) == 1) {
- fs->pc--; /* erase previous instruction */
- luaK_deltastack(fs, -1); /* correct stack */
- return NO_JUMP;
- }
- break;
- }
- default: break;
- }
- break;
- }
- case OP_JMPF:
- case OP_JMPONF: {
- switch (GET_OPCODE(i)) {
- case OP_NOT: {
- i = CREATE_S(OP_JMPT, NO_JUMP);
- optm = 1;
- break;
- }
- case OP_PUSHINT: { /* `while 1 do ...' */
- fs->pc--; /* erase previous instruction */
- luaK_deltastack(fs, -1); /* correct stack */
- return NO_JUMP;
- }
- case OP_PUSHNIL: { /* `repeat ... until nil' */
- if (GETARG_U(i) == 1) {
- i = CREATE_S(OP_JMP, NO_JUMP);
- optm = 1;
- }
- break;
- }
- default: break;
- }
- break;
- }
- case OP_GETDOTTED:
- case OP_GETINDEXED:
- case OP_TAILCALL:
- case OP_ADDI: {
- LUA_INTERNALERROR("instruction used only for optimizations");
- break;
- }
- default: {
- LUA_ASSERT(delta != VD, "invalid delta");
- break;
- }
- }
- luaK_deltastack(fs, delta);
- if (optm) { /* optimize: put instruction in place of last one */
- fs->f->code[fs->pc-1] = i; /* change previous instruction */
- return fs->pc-1; /* do not generate new instruction */
- }
- /* else build new instruction */
- switch ((enum Mode)luaK_opproperties[o].mode) {
- case iO: i = CREATE_0(o); break;
- case iU: i = CREATE_U(o, arg1); break;
- case iS: i = CREATE_S(o, arg1); break;
- case iAB: i = CREATE_AB(o, arg1, arg2); break;
- }
- codelineinfo(fs);
- /* put new instruction in code array */
- luaM_growvector(fs->L, fs->f->code, fs->pc, 1, Instruction,
- "code size overflow", MAX_INT);
- fs->f->code[fs->pc] = i;
- return fs->pc++;
- }
- const struct OpProperties luaK_opproperties[NUM_OPCODES] = {
- {iO, 0, 0}, /* OP_END */
- {iU, 0, 0}, /* OP_RETURN */
- {iAB, 0, 0}, /* OP_CALL */
- {iAB, 0, 0}, /* OP_TAILCALL */
- {iU, VD, 0}, /* OP_PUSHNIL */
- {iU, VD, 0}, /* OP_POP */
- {iS, 1, 0}, /* OP_PUSHINT */
- {iU, 1, 0}, /* OP_PUSHSTRING */
- {iU, 1, 0}, /* OP_PUSHNUM */
- {iU, 1, 0}, /* OP_PUSHNEGNUM */
- {iU, 1, 0}, /* OP_PUSHUPVALUE */
- {iU, 1, 0}, /* OP_GETLOCAL */
- {iU, 1, 0}, /* OP_GETGLOBAL */
- {iO, 1, 2}, /* OP_GETTABLE */
- {iU, 1, 1}, /* OP_GETDOTTED */
- {iU, 1, 1}, /* OP_GETINDEXED */
- {iU, 2, 1}, /* OP_PUSHSELF */
- {iU, 1, 0}, /* OP_CREATETABLE */
- {iU, 0, 1}, /* OP_SETLOCAL */
- {iU, 0, 1}, /* OP_SETGLOBAL */
- {iAB, VD, 0}, /* OP_SETTABLE */
- {iAB, VD, 0}, /* OP_SETLIST */
- {iU, VD, 0}, /* OP_SETMAP */
- {iO, 1, 2}, /* OP_ADD */
- {iS, 1, 1}, /* OP_ADDI */
- {iO, 1, 2}, /* OP_SUB */
- {iO, 1, 2}, /* OP_MULT */
- {iO, 1, 2}, /* OP_DIV */
- {iO, 1, 2}, /* OP_POW */
- {iU, VD, 0}, /* OP_CONCAT */
- {iO, 1, 1}, /* OP_MINUS */
- {iO, 1, 1}, /* OP_NOT */
- {iS, 0, 2}, /* OP_JMPNE */
- {iS, 0, 2}, /* OP_JMPEQ */
- {iS, 0, 2}, /* OP_JMPLT */
- {iS, 0, 2}, /* OP_JMPLE */
- {iS, 0, 2}, /* OP_JMPGT */
- {iS, 0, 2}, /* OP_JMPGE */
- {iS, 0, 1}, /* OP_JMPT */
- {iS, 0, 1}, /* OP_JMPF */
- {iS, 0, 1}, /* OP_JMPONT */
- {iS, 0, 1}, /* OP_JMPONF */
- {iS, 0, 0}, /* OP_JMP */
- {iO, 0, 0}, /* OP_PUSHNILJMP */
- {iS, 0, 0}, /* OP_FORPREP */
- {iS, 0, 3}, /* OP_FORLOOP */
- {iS, 2, 0}, /* OP_LFORPREP */
- {iS, 0, 3}, /* OP_LFORLOOP */
- {iAB, VD, 0} /* OP_CLOSURE */
- };