Modules: Code generation of enum constants for merged enum definitions

Found in a bootstrap of LLVM with implicit modules, resulting in a
deadlock of some Orc unit tests with libstdc++ 8.1. An enum was used as
part of the implementation of std::recursive_mutex and this bug resulted
in the constant initialization of zero instead of the desired non-zero
value. => Badness.

Richard Smith tells me neither of these fields are necessarily canonical
& so using declaresSamEntity is the right solution here (rather than
changing both of these Fields to be canonical by construction/from their
source)

llvm-svn: 361428

1 files changed, 36 insertions, 0 deletions

diff --git a/clang/test/Modules/enum-codegen.cpp b/clang/test/Modules/enum-codegen.cpp
new file mode 100644
index 00000000000..87c1c5a9d47
--- /dev/null
+++ b/clang/test/Modules/enum-codegen.cpp
@@ -0,0 +1,36 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t %s -emit-llvm -o - | FileCheck %s
+
+// CHECK: @_Z3varIiE = {{.*}} %union.union_type { i8 1 },
+
+#pragma clang module build bar
+module bar {
+  header "bar.h" { size 40 mtime 0 }
+  export *
+}
+#pragma clang module contents
+#pragma clang module begin bar
+union union_type {
+  char h{1};
+};
+#pragma clang module end
+#pragma clang module endbuild
+#pragma clang module build foo
+module foo {
+  header "foo.h" { size 97 mtime 0 }
+  export *
+}
+#pragma clang module contents
+#pragma clang module begin foo
+union union_type {
+  char h{1};
+};
+#pragma clang module import bar
+template<typename T>
+union_type var;
+#pragma clang module end
+#pragma clang module endbuild
+#pragma clang module import foo
+int main() {
+  (void)&var<int>;
+}