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https://github.com/lua/lua.git
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cleaner implementation of code generation for jumps
This commit is contained in:
Roberto Ierusalimschy
parent
b487975344
commit
2dadc81822
65
lcode.c
65
lcode.c
@ -1,5 +1,5 @@
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/*
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** $Id: lcode.c,v 1.100 2002/05/09 14:14:34 roberto Exp roberto $
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** $Id: lcode.c,v 1.101 2002/05/10 17:02:32 roberto Exp roberto $
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** Code generator for Lua
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** See Copyright Notice in lua.h
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*/
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@ -39,58 +39,48 @@ void luaK_nil (FuncState *fs, int from, int n) {
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}
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void luaK_moveexp (expdesc *e, int offset) {
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if (e->t != NO_JUMP) e->t += offset;
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if (e->f != NO_JUMP) e->f += offset;
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if (e->k == VRELOCABLE || e->k == VJMP) e->info += offset;
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}
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int luaK_jump (FuncState *fs) {
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int j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
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if (j == fs->lasttarget) { /* possible jumps to this jump? */
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luaK_concat(fs, &j, fs->jlt); /* keep them on hold */
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fs->jlt = NO_JUMP;
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}
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int jpc = fs->jpc; /* save list of jumps to here */
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int j;
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fs->jpc = NO_JUMP;
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j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
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luaK_concat(fs, &j, jpc); /* keep them on hold */
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return j;
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}
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static int luaK_condjump (FuncState *fs, OpCode op, int A, int B, int C) {
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luaK_codeABC(fs, op, A, B, C);
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return luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
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return luaK_jump(fs);
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}
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static void luaK_fixjump (FuncState *fs, int pc, int dest) {
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Instruction *jmp = &fs->f->code[pc];
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if (dest == NO_JUMP)
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SETARG_sBx(*jmp, NO_JUMP); /* point to itself to represent end of list */
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else { /* jump is relative to position following jump instruction */
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int offset = dest-(pc+1);
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if (abs(offset) > MAXARG_sBx)
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luaX_syntaxerror(fs->ls, "control structure too long");
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SETARG_sBx(*jmp, offset);
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}
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int offset = dest-(pc+1);
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lua_assert(dest != NO_JUMP);
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if (abs(offset) > MAXARG_sBx)
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luaX_syntaxerror(fs->ls, "control structure too long");
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SETARG_sBx(*jmp, offset);
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}
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/*
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** returns current `pc' and marks it as a jump target (to avoid wrong
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** optimizations with consecutive instructions not in the same basic block).
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** discharge list of jumps to last target.
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*/
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int luaK_getlabel (FuncState *fs) {
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if (fs->pc != fs->lasttarget) {
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int lasttarget = fs->lasttarget;
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fs->lasttarget = fs->pc;
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luaK_patchlist(fs, fs->jlt, lasttarget); /* discharge old list `jlt' */
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fs->jlt = NO_JUMP; /* nobody jumps to this new label (yet) */
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}
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fs->lasttarget = fs->pc;
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return fs->pc;
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}
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void luaK_dischargejpc (FuncState *fs) {
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luaK_patchlist(fs, fs->jpc, fs->pc); /* discharge old list `jpc' */
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fs->jpc = NO_JUMP;
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}
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static int luaK_getjump (FuncState *fs, int pc) {
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int offset = GETARG_sBx(fs->f->code[pc]);
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if (offset == NO_JUMP) /* point to itself represents end of list */
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@ -155,20 +145,20 @@ static void luaK_patchlistaux (FuncState *fs, int list,
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void luaK_patchlist (FuncState *fs, int list, int target) {
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if (target == fs->lasttarget) /* same target that list `jlt'? */
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luaK_concat(fs, &fs->jlt, list); /* delay fixing */
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else
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luaK_patchlistaux(fs, list, target, NO_REG, target, NO_REG, target);
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lua_assert(target <= fs->pc);
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luaK_patchlistaux(fs, list, target, NO_REG, target, NO_REG, target);
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}
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void luaK_patchtohere (FuncState *fs, int list) {
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luaK_patchlist(fs, list, luaK_getlabel(fs));
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luaK_getlabel(fs);
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luaK_concat(fs, &fs->jpc, list);
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}
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void luaK_concat (FuncState *fs, int *l1, int l2) {
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if (*l1 == NO_JUMP)
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if (l2 == NO_JUMP) return;
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else if (*l1 == NO_JUMP)
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*l1 = l2;
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else {
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int list = *l1;
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@ -508,7 +498,7 @@ void luaK_goiftrue (FuncState *fs, expdesc *e) {
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break;
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}
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case VFALSE: {
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pc = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP); /* always jump */
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pc = luaK_jump(fs); /* always jump */
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break;
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}
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case VJMP: {
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@ -534,7 +524,7 @@ void luaK_goiffalse (FuncState *fs, expdesc *e) {
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break;
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}
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case VTRUE: {
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pc = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP); /* always jump */
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pc = luaK_jump(fs); /* always jump */
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break;
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}
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case VJMP: {
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@ -737,6 +727,7 @@ void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
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int luaK_code (FuncState *fs, Instruction i, int line) {
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Proto *f = fs->f;
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int oldsize = f->sizecode;
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luaK_dischargejpc(fs); /* `pc' will change */
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/* put new instruction in code array */
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luaM_growvector(fs->L, f->code, fs->pc, f->sizecode, Instruction,
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MAX_INT, "code size overflow");
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4
lcode.h
4
lcode.h
@ -1,5 +1,5 @@
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/*
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** $Id: lcode.h,v 1.33 2002/05/07 17:36:56 roberto Exp roberto $
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** $Id: lcode.h,v 1.34 2002/05/10 17:02:32 roberto Exp roberto $
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** Code generator for Lua
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** See Copyright Notice in lua.h
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*/
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@ -55,12 +55,12 @@ void luaK_exp2val (FuncState *fs, expdesc *e);
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int luaK_exp2RK (FuncState *fs, expdesc *e);
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void luaK_self (FuncState *fs, expdesc *e, expdesc *key);
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void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k);
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void luaK_moveexp (expdesc *e, int offset);
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void luaK_goiftrue (FuncState *fs, expdesc *e);
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void luaK_goiffalse (FuncState *fs, expdesc *e);
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void luaK_storevar (FuncState *fs, expdesc *var, expdesc *e);
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void luaK_setcallreturns (FuncState *fs, expdesc *var, int nresults);
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int luaK_jump (FuncState *fs);
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void luaK_dischargejpc (FuncState *fs);
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void luaK_patchlist (FuncState *fs, int list, int target);
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void luaK_patchtohere (FuncState *fs, int list);
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void luaK_concat (FuncState *fs, int *l1, int l2);
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26
lparser.c
26
lparser.c
@ -1,5 +1,5 @@
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/*
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** $Id: lparser.c,v 1.179 2002/05/07 17:36:56 roberto Exp roberto $
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** $Id: lparser.c,v 1.180 2002/05/10 17:02:32 roberto Exp roberto $
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** Lua Parser
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** See Copyright Notice in lua.h
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*/
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@ -367,7 +367,7 @@ static void open_func (LexState *ls, FuncState *fs) {
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ls->fs = fs;
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fs->pc = 0;
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fs->lasttarget = 0;
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fs->jlt = NO_JUMP;
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fs->jpc = NO_JUMP;
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fs->freereg = 0;
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fs->nk = 0;
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fs->h = luaH_new(ls->L, 0, 0);
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@ -391,7 +391,6 @@ static void close_func (LexState *ls) {
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Proto *f = fs->f;
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removevars(ls, 0);
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luaK_codeABC(fs, OP_RETURN, 0, 1, 0); /* final return */
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luaK_getlabel(fs); /* close eventual list of pending jumps */
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lua_assert(G(L)->roottable == fs->h);
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G(L)->roottable = fs->h->next;
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luaH_free(L, fs->h);
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@ -977,30 +976,33 @@ static void whilestat (LexState *ls, int line) {
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int i;
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int sizeexp;
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FuncState *fs = ls->fs;
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int while_init = luaK_getlabel(fs);
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int whileinit, blockinit, expinit;
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expdesc v;
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BlockCnt bl;
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next(ls);
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whileinit = luaK_jump(fs);
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expinit = luaK_getlabel(fs);
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expr(ls, &v);
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if (v.k == VK) v.k = VTRUE; /* `trues' are all equal here */
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lineexp = ls->linenumber;
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luaK_goiffalse(fs, &v);
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sizeexp = fs->pc - while_init;
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luaK_dischargejpc(fs);
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sizeexp = fs->pc - expinit;
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if (sizeexp > MAXEXPWHILE)
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luaX_syntaxerror(ls, "while condition too complex");
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fs->pc = while_init; /* remove `exp' code */
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luaK_getlabel(fs);
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for (i = 0; i < sizeexp; i++) /* save `exp' code */
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codeexp[i] = fs->f->code[while_init + i];
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luaK_jump(fs);
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codeexp[i] = fs->f->code[expinit + i];
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fs->pc = expinit; /* remove `exp' code */
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enterblock(fs, &bl, 1);
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check(ls, TK_DO);
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blockinit = luaK_getlabel(fs);
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block(ls);
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luaK_patchtohere(fs, while_init); /* initial jump jumps to here */
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luaK_moveexp(&v, fs->pc - while_init); /* correct pointers */
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luaK_patchtohere(fs, whileinit); /* initial jump jumps to here */
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if (v.t != NO_JUMP) v.t += fs->pc - expinit;
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if (v.f != NO_JUMP) v.f += fs->pc - expinit;
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for (i=0; i<sizeexp; i++)
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luaK_code(fs, codeexp[i], lineexp);
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luaK_patchlist(fs, v.t, while_init+1);
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luaK_patchlist(fs, v.t, blockinit);
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luaK_patchtohere(fs, v.f);
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check_match(ls, TK_END, TK_WHILE, line);
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leaveblock(fs);
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@ -1,5 +1,5 @@
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/*
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** $Id: lparser.h,v 1.41 2002/03/25 17:47:14 roberto Exp roberto $
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** $Id: lparser.h,v 1.42 2002/05/09 18:00:38 roberto Exp roberto $
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** Lua Parser
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** See Copyright Notice in lua.h
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*/
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@ -63,7 +63,7 @@ typedef struct FuncState {
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struct BlockCnt *bl; /* chain of current blocks */
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int pc; /* next position to code (equivalent to `ncode') */
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int lasttarget; /* `pc' of last `jump target' */
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int jlt; /* list of jumps to `lasttarget' */
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int jpc; /* list of jumps to `pc' */
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int freereg; /* first free register */
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int defaultglob; /* where to look for non-declared globals */
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int nk; /* number of elements in `k' */
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