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Allow address expressions in ?c after int casts.

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This fixes ocaml on non-x86 architectures, where we have code
that looks like:

	#define Fl_head ((uintptr_t)(&sentinel.first_field))

Without this change, we get an error about a non-constant
initializer. This change takes the checks for pointers and
makes them apply to all expressions. It also makes the checks
stricter, preventing the following from compiling to junk:

	int x;
	int y = 42;
	int *p = &x + y
This commit is contained in:
Ori Bernstein 2019-09-07 18:25:04 -07:00
parent 2917cb1d17
commit 71939a82cc
1 changed files with 20 additions and 20 deletions
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40
sys/src/cmd/cc/dcl.c
View file

@ -373,35 +373,35 @@ init1(Sym *s, Type *t, long o, int exflag)
goto gext; goto gext;
} }
if(t->etype == TIND) { if(t->etype == TIND) {
while(a->op == OCAST) { if(a->op == OCAST)
warn(a, "CAST in initialization ignored"); warn(a, "CAST in initialization ignored");
a = a->left; if(!sametype(t, a->type))
}
if(!sametype(t, a->type)) {
diag(a, "initialization of incompatible pointers: %s\n%T and %T", diag(a, "initialization of incompatible pointers: %s\n%T and %T",
s->name, t, a->type); s->name, t, a->type);
}
switch(a->op) {
case OADDR:
a = a->left;
break;
case ONAME:
case OIND:
diag(a, "initializer is not a constant: %s", s->name);
return Z;
}
goto gext;
} }
while(a->op == OCAST) while(a->op == OCAST)
a = a->left; a = a->left;
if(a->op == OADDR) {
warn(a, "initialize pointer to an integer: %s", s->name); switch(a->op) {
case OADDR:
if(t->etype != TIND)
warn(a, "initialize pointer to an integer: %s", s->name);
a = a->left; a = a->left;
goto gext; break;
case OADD:
/*
* Constants will be folded before this point, which just leaves offsets
* from names.
*/
l = a->left;
r = a->right;
if(l->op == OADDR && r->op == OCONST || r->op == OADDR && l->op == OCONST)
break;
default:
diag(a, "initializer is not a constant: %s", s->name);
return Z;
} }
diag(a, "initializer is not a constant: %s", s->name);
return Z;
gext: gext:
gextern(s, a, o, t->width); gextern(s, a, o, t->width);