[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, 18 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/pass-object-size.cpp b/clang/test/CodeGenCXX/pass-object-size.cpp
index 254669b9..2c7f974 100644
--- a/clang/test/CodeGenCXX/pass-object-size.cpp
+++ b/clang/test/CodeGenCXX/pass-object-size.cpp
@@ -25,3 +25,21 @@ void Lambdas(char *ptr) {
 // CHECK-DAG: define internal i64 @"_ZZN7lambdas7LambdasEPcENK3$_1clEPvU17pass_object_size0"
 // CHECK-NOT: call i64 @llvm.objectsize
 }
+
+// This is here instead of in Sema/ because we need to check to make sure the
+// proper function is called. If it's not, we'll end up with assertion errors.
+namespace addrof {
+void OvlFoo(void *const __attribute__((pass_object_size(0)))) {}
+void OvlFoo(int *const) {}
+
+// CHECK: define void @_ZN6addrof4TestEv
+void Test() {
+  // Treating parens-only calls as though they were direct is consistent with
+  // how we handle other implicitly unaddressable functions (e.g. builtins).
+  // CHECK: call void @_ZN6addrof6OvlFooEPvU17pass_object_size0
+  (OvlFoo)(nullptr);
+
+  // CHECK: call void @_ZN6addrof6OvlFooEPi
+  (&OvlFoo)(nullptr);
+}
+}