https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70073
Bug ID: 70073
Summary: -Werror=return-type ignores call to function with
attribute noreturn
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: douglas.bagnall at catalyst dot net.nz
Target Milestone: ---
GCC 6 (or more precisely, "git-svn-id:
svn+ssh://gcc.gnu.org/svn/gcc/trunk@233864
138bc75d-0d04-0410-961f-82ee72b054a4"), fails to compile Samba with -Werror,
with this message:
../source4/heimdal/lib/hx509/sel.c: In function ‘_hx509_expr_eval’:
../source4/heimdal/lib/hx509/sel.c:180:1: error: control reaches end of
non-void function [-Werror=return-type]
}
^
I have failed to make a minimal testcase, but this is what is happening. In
headers:
#define UNREACHABLE(x)
void
_hx509_abort (
const char */*fmt*/,
...)
__attribute__ ((noreturn, format (printf, 1, 2)));
and the default case in this function triggers the error:
int
_hx509_expr_eval(hx509_context context, hx509_env env, struct hx_expr *expr)
{
switch (expr->op) {
case op_TRUE:
return 1;
case op_FALSE:
return 0;
case op_NOT:
return ! _hx509_expr_eval(context, env, expr->arg1);
case op_AND:
return _hx509_expr_eval(context, env, expr->arg1) &&
_hx509_expr_eval(context, env, expr->arg2);
case op_OR:
return _hx509_expr_eval(context, env, expr->arg1) ||
_hx509_expr_eval(context, env, expr->arg2);
case op_COMP:
return eval_comp(context, env, expr->arg1);
default:
_hx509_abort("hx509 eval expr with unknown op: %d", (int)expr->op);
UNREACHABLE(return 0);
}
}
As you can see, cpp converts the "UNREACHABLE(return 0)" to nothing, but GCC
fails to notice that _hx509_abort() does not return.
Previous versions of GCC have compiled this without trouble.
