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bug with interaction of variables

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declared in cases and heap allocation

R=r
OCL=26064
CL=26064
This commit is contained in:
Ken Thompson 2009-03-10 16:49:34 -07:00
parent b2e91a9a29
commit 0c4f4587d7
2 changed files with 29 additions and 6 deletions
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4
src/cmd/6g/reg.c
View File

@ -787,7 +787,9 @@ mkvar(Reg *r, Adr *a)
s = a->sym;
if(s == S)
goto none;
if(s->name[0] == '!' || s->name[0] == '.')
// if(s->name[0] == '!')
// goto none;
if(s->name[0] == '.')
goto none;
et = a->etype;
o = a->offset;

31
src/cmd/gc/swt.c
View File

@ -189,7 +189,6 @@ casebody(Node *sw)
br = nod(OBREAK, N, N);
loop:
if(t == N) {
if(oc == N && os != N)
yyerror("first switch statement must be a case");
@ -259,12 +258,12 @@ loop:
* rebulid case statements into if .. goto
*/
void
prepsw(Node *sw, int arg)
exprswitch(Node *sw, int arg)
{
Iter save;
Node *name, *bool, *cas;
Node *t, *a;
//dump("prepsw before", sw->nbody->left);
//dump("exprswitch before", sw->nbody->left);
cas = N;
name = N;
@ -281,7 +280,7 @@ prepsw(Node *sw, int arg)
loop:
if(t == N) {
sw->nbody->left = rev(cas);
//dump("prepsw after", sw->nbody->left);
//dump("exprswitch after", sw->nbody->left);
return;
}
@ -291,6 +290,16 @@ loop:
goto loop;
}
// pull out the dcl in case this
// variable is allocated on the heap.
// this should be done better to prevent
// multiple (unused) heap allocations per switch.
if(t->ninit != N && t->ninit->op == ODCL) {
//dump("exprswitch case init", t->ninit);
cas = list(cas, t->ninit);
t->ninit = N;
}
if(t->left->op == OAS) {
if(bool == N) {
bool = nod(OXXX, N, N);
@ -394,6 +403,18 @@ loop:
goto loop;
}
// pull out the dcl in case this
// variable is allocated on the heap.
// this should be done better to prevent
// multiple (unused) heap allocations per switch.
// not worth doing now -- make a binary search
// on contents of signature instead.
if(t->ninit != N && t->ninit->op == ODCL) {
//dump("typeswitch case init", t->ninit);
cas = list(cas, t->ninit);
t->ninit = N;
}
a = t->left->left; // var
a = nod(OLIST, a, bool); // var,bool
@ -476,7 +497,7 @@ walkswitch(Node *sw)
/*
* convert the switch into OIF statements
*/
prepsw(sw, arg);
exprswitch(sw, arg);
walkstate(sw->nbody);
//print("normal done\n");
}