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corrected 'follow' for checking whether label is last statement

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in a block
This commit is contained in:
Roberto Ierusalimschy
2011-02-09 14:51:28 -02:00
parent 0539f48661
commit e7192dfdbb
1 changed files with 21 additions and 14 deletions
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35
lparser.c
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@@ -1,5 +1,5 @@
/* /*
** $Id: lparser.c,v 2.100 2011/02/07 19:00:30 roberto Exp roberto $ ** $Id: lparser.c,v 2.101 2011/02/09 14:45:19 roberto Exp roberto $
** Lua Parser ** Lua Parser
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -342,7 +342,7 @@ static void closegoto (LexState *ls, int g, Labeldesc *label) {
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
Dyndata *dyd = ls->dyd; Dyndata *dyd = ls->dyd;
Labeldesc *gt = &dyd->gt.arr[g]; Labeldesc *gt = &dyd->gt.arr[g];
lua_assert(gt->name == label->name); lua_assert(eqstr(gt->name, label->name));
if (gt->nactvar < label->nactvar) { if (gt->nactvar < label->nactvar) {
const char *msg = luaO_pushfstring(ls->L, const char *msg = luaO_pushfstring(ls->L,
"<goto %s> at line %d jumps into the scope of local " LUA_QS, "<goto %s> at line %d jumps into the scope of local " LUA_QS,
@@ -368,7 +368,7 @@ static int findlabel (LexState *ls, int g) {
/* check labels in current block for a match */ /* check labels in current block for a match */
for (i = bl->firstlabel; i < dyd->label.n; i++) { for (i = bl->firstlabel; i < dyd->label.n; i++) {
Labeldesc *lb = &dyd->label.arr[i]; Labeldesc *lb = &dyd->label.arr[i];
if (lb->name == gt->name) { /* correct label? */ if (eqstr(lb->name, gt->name)) { /* correct label? */
if (gt->nactvar > lb->nactvar && if (gt->nactvar > lb->nactvar &&
(bl->upval || dyd->label.n > bl->firstlabel)) (bl->upval || dyd->label.n > bl->firstlabel))
luaK_patchclose(ls->fs, gt->pc, lb->nactvar); luaK_patchclose(ls->fs, gt->pc, lb->nactvar);
@@ -388,7 +388,7 @@ static void findgotos (LexState *ls, Labeldesc *lb) {
int i; int i;
Dyndata *dyd = ls->dyd; Dyndata *dyd = ls->dyd;
for (i = ls->fs->bl->firstgoto; i < dyd->gt.n; i++) { for (i = ls->fs->bl->firstgoto; i < dyd->gt.n; i++) {
if (dyd->gt.arr[i].name == lb->name) if (eqstr(dyd->gt.arr[i].name, lb->name))
closegoto(ls, i, lb); closegoto(ls, i, lb);
} }
} }
@@ -439,7 +439,7 @@ static void leaveblock (FuncState *fs) {
ls->dyd->label.n = bl->firstlabel; /* remove local labels */ ls->dyd->label.n = bl->firstlabel; /* remove local labels */
if (bl->previous) /* inner block? */ if (bl->previous) /* inner block? */
movegotosout(fs, bl); /* update pending gotos to outer block */ movegotosout(fs, bl); /* update pending gotos to outer block */
else if (bl->firstgoto < ls->dyd->gt.n) { /* check pending gotos */ else if (bl->firstgoto < ls->dyd->gt.n) { /* pending gotos in outer block? */
Labeldesc *gt = &ls->dyd->gt.arr[bl->firstgoto]; Labeldesc *gt = &ls->dyd->gt.arr[bl->firstgoto];
const char *msg = luaO_pushfstring(ls->L, const char *msg = luaO_pushfstring(ls->L,
"label " LUA_QS " (<goto> at line %d) undefined", "label " LUA_QS " (<goto> at line %d) undefined",
@@ -1048,11 +1048,17 @@ static void expr (LexState *ls, expdesc *v) {
*/ */
static int block_follow (int token) { /*
switch (token) { ** check whether current token is in the follow set of a block.
case TK_ELSE: case TK_ELSEIF: case TK_END: ** 'until' closes syntactical blocks, but do not close scope,
case TK_UNTIL: case TK_EOS: ** so it handled in separate.
*/
static int block_follow (LexState *ls, int withuntil) {
switch (ls->t.token) {
case TK_ELSE: case TK_ELSEIF:
case TK_END: case TK_EOS:
return 1; return 1;
case TK_UNTIL: return withuntil;
default: return 0; default: return 0;
} }
} }
@@ -1207,10 +1213,11 @@ static void labelstat (LexState *ls, TString *label) {
/* create new entry for this label */ /* create new entry for this label */
l = newlabelentry(ls, &ls->dyd->label, label, 0, fs->pc); l = newlabelentry(ls, &ls->dyd->label, label, 0, fs->pc);
lb = &ls->dyd->label.arr[l]; lb = &ls->dyd->label.arr[l];
/* if label is last statement in the block, while (testnext(ls, ';')) ; /* skip trailing semicolons */
assume that local variables are already out of scope */ if (block_follow(ls, 0)) { /* label is last statement in the block? */
if (ls->t.token == TK_END) /* assume that locals are already out of scope */
lb->nactvar = fs->bl->nactvar; lb->nactvar = fs->bl->nactvar;
}
findgotos(ls, lb); findgotos(ls, lb);
} }
@@ -1470,7 +1477,7 @@ static void retstat (LexState *ls) {
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
expdesc e; expdesc e;
int first, nret; /* registers with returned values */ int first, nret; /* registers with returned values */
if (block_follow(ls->t.token) || ls->t.token == ';') if (block_follow(ls, 1) || ls->t.token == ';')
first = nret = 0; /* return no values */ first = nret = 0; /* return no values */
else { else {
nret = explist1(ls, &e); /* optional return values */ nret = explist1(ls, &e); /* optional return values */
@@ -1570,7 +1577,7 @@ static void statlist (LexState *ls) {
/* statlist -> { stat [`;'] } */ /* statlist -> { stat [`;'] } */
int islast = 0; int islast = 0;
enterlevel(ls); enterlevel(ls);
while (!islast && !block_follow(ls->t.token)) { while (!islast && !block_follow(ls, 1)) {
islast = statement(ls); islast = statement(ls);
if (islast) if (islast)
testnext(ls, ';'); testnext(ls, ';');