[Sema] Teach overload resolution about unaddressable functions.

Given an expression like `(&Foo)();`, we perform overload resolution as
if we are calling `Foo` directly. This causes problems if `Foo` is a
function that can't have its address taken. This patch teaches overload
resolution to ignore functions that can't have their address taken in
such cases.

Differential Revision: http://reviews.llvm.org/D15590

llvm-svn: 257016

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/pass-object-size.cpp b/clang/test/SemaCXX/pass-object-size.cpp
index bec0c1c55f2..94c9cc9c8aa 100644
--- a/clang/test/SemaCXX/pass-object-size.cpp
+++ b/clang/test/SemaCXX/pass-object-size.cpp
@@ -120,3 +120,17 @@ void Bar() {
   (void)+[](void *const p __attribute__((pass_object_size(0)))) {}; //expected-error-re{{invalid argument type '(lambda at {{.*}})' to unary expression}}
 }
 }
+
+namespace ovlbug {
+// Directly calling an address-of function expression (e.g. in (&foo)(args...))
+// doesn't go through regular address-of-overload logic. This caused the above
+// code to generate an ICE.
+void DirectAddrOf(void *__attribute__((pass_object_size(0))));
+void DirectAddrOfOvl(void *__attribute__((pass_object_size(0))));
+void DirectAddrOfOvl(int *);
+
+void Test() {
+  (&DirectAddrOf)(nullptr); //expected-error{{cannot take address of function 'DirectAddrOf' because parameter 1 has pass_object_size attribute}}
+  (&DirectAddrOfOvl)((char*)nullptr); //expected-error{{no matching function}} expected-note@129{{candidate address cannot be taken because parameter 1 has pass_object_size attribute}} expected-note@130{{candidate function not viable: no known conversion from 'char *' to 'int *' for 1st argument}}
+}
+}