[PR30341] Alias must point to a definition

Inlining the destructor caused the compiler to generate bad IR which failed the Verifier in the backend.
https://llvm.org/bugs/show_bug.cgi?id=30341

This patch disables alias to available_externally definitions.

Reviewers: eugenis, rsmith

Differential Revision: https://reviews.llvm.org/D24682

llvm-svn: 282679

1 files changed, 19 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/alias-available-externally.cpp b/clang/test/CodeGenCXX/alias-available-externally.cpp
new file mode 100644
index 00000000000..264af558377
--- /dev/null
+++ b/clang/test/CodeGenCXX/alias-available-externally.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -O1 -std=c++11 -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s
+// Clang should not generate alias to available_externally definitions.
+// Check that the destructor of Foo is defined.
+// CHECK: define linkonce_odr void @_ZN3FooD2Ev
+template <class CharT>
+struct String {
+  String() {}
+  ~String();
+};
+
+template <class CharT>
+inline __attribute__((visibility("hidden"), always_inline))
+String<CharT>::~String() {}
+
+extern template struct String<char>;
+
+struct Foo : public String<char> { Foo() { String<char> s; } };
+
+Foo f;