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cleaner implementation of code generation for jumps

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This commit is contained in:
Roberto Ierusalimschy
2002-05-10 16:22:11 -03:00
parent b487975344
commit 2dadc81822
4 changed files with 46 additions and 53 deletions
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26
lparser.c
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@@ -1,5 +1,5 @@
/*
** $Id: lparser.c,v 1.179 2002/05/07 17:36:56 roberto Exp roberto $
** $Id: lparser.c,v 1.180 2002/05/10 17:02:32 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -367,7 +367,7 @@ static void open_func (LexState *ls, FuncState *fs) {
ls->fs = fs;
fs->pc = 0;
fs->lasttarget = 0;
fs->jlt = NO_JUMP;
fs->jpc = NO_JUMP;
fs->freereg = 0;
fs->nk = 0;
fs->h = luaH_new(ls->L, 0, 0);
@@ -391,7 +391,6 @@ static void close_func (LexState *ls) {
Proto *f = fs->f;
removevars(ls, 0);
luaK_codeABC(fs, OP_RETURN, 0, 1, 0); /* final return */
luaK_getlabel(fs); /* close eventual list of pending jumps */
lua_assert(G(L)->roottable == fs->h);
G(L)->roottable = fs->h->next;
luaH_free(L, fs->h);
@@ -977,30 +976,33 @@ static void whilestat (LexState *ls, int line) {
int i;
int sizeexp;
FuncState *fs = ls->fs;
int while_init = luaK_getlabel(fs);
int whileinit, blockinit, expinit;
expdesc v;
BlockCnt bl;
next(ls);
whileinit = luaK_jump(fs);
expinit = luaK_getlabel(fs);
expr(ls, &v);
if (v.k == VK) v.k = VTRUE; /* `trues' are all equal here */
lineexp = ls->linenumber;
luaK_goiffalse(fs, &v);
sizeexp = fs->pc - while_init;
luaK_dischargejpc(fs);
sizeexp = fs->pc - expinit;
if (sizeexp > MAXEXPWHILE)
luaX_syntaxerror(ls, "while condition too complex");
fs->pc = while_init; /* remove `exp' code */
luaK_getlabel(fs);
for (i = 0; i < sizeexp; i++) /* save `exp' code */
codeexp[i] = fs->f->code[while_init + i];
luaK_jump(fs);
codeexp[i] = fs->f->code[expinit + i];
fs->pc = expinit; /* remove `exp' code */
enterblock(fs, &bl, 1);
check(ls, TK_DO);
blockinit = luaK_getlabel(fs);
block(ls);
luaK_patchtohere(fs, while_init); /* initial jump jumps to here */
luaK_moveexp(&v, fs->pc - while_init); /* correct pointers */
luaK_patchtohere(fs, whileinit); /* initial jump jumps to here */
if (v.t != NO_JUMP) v.t += fs->pc - expinit;
if (v.f != NO_JUMP) v.f += fs->pc - expinit;
for (i=0; i<sizeexp; i++)
luaK_code(fs, codeexp[i], lineexp);
luaK_patchlist(fs, v.t, while_init+1);
luaK_patchlist(fs, v.t, blockinit);
luaK_patchtohere(fs, v.f);
check_match(ls, TK_END, TK_WHILE, line);
leaveblock(fs);