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small bug in if-goto optimization: block must be closed ('leaveblock')

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*before* the jump out ('escapelist')
This commit is contained in:
Roberto Ierusalimschy
2011-09-14 14:40:26 -03:00
parent 5ea8f108e1
commit 500336efd0
1 changed files with 8 additions and 5 deletions
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13
lparser.c
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@@ -1,5 +1,5 @@
/*
** $Id: lparser.c,v 2.117 2011/08/25 13:45:24 roberto Exp roberto $
** $Id: lparser.c,v 2.118 2011/08/30 16:38:58 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -1376,27 +1376,30 @@ static void test_then_block (LexState *ls, int *escapelist) {
expdesc v;
int jf; /* instruction to skip 'then' code (if condition is false) */
luaX_next(ls); /* skip IF or ELSEIF */
enterblock(fs, &bl, 0);
expr(ls, &v); /* read condition */
checknext(ls, TK_THEN);
if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) {
luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */
enterblock(fs, &bl, 0); /* must enter block before 'goto' */
gotostat(ls, v.t); /* handle goto/break */
if (block_follow(ls, 0)) /* no more code after 'goto'? */
goto leave; /* that is it */
if (block_follow(ls, 0)) { /* 'goto' is the entire block? */
leaveblock(fs);
return; /* and that is it */
}
else /* must skip over 'then' part if condition is false */
jf = luaK_jump(fs);
}
else { /* regular case (not goto/break) */
luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */
enterblock(fs, &bl, 0);
jf = v.f;
}
statlist(ls); /* `then' part */
leaveblock(fs);
if (ls->t.token == TK_ELSE ||
ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */
luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */
luaK_patchtohere(fs, jf);
leave: leaveblock(fs);
}