Implement __declspec(selectany) under -fms-extensions
selectany only applies to externally visible global variables. It has
the effect of making the data weak_odr.
The MSDN docs suggest that unused definitions can only be dropped at
linktime, so Clang uses weak instead of linkonce. MSVC optimizes away
references to constant selectany data, so it must assume that there is
only one definition, hence weak_odr.
Reviewers: espindola
Differential Revision: http://llvm-reviews.chandlerc.com/D814
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182266 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/ms-declspecs.c b/test/CodeGen/ms-declspecs.c
index 26bdc58..5dc7787 100644
--- a/test/CodeGen/ms-declspecs.c
+++ b/test/CodeGen/ms-declspecs.c
@@ -1,5 +1,10 @@
// RUN: %clang_cc1 -triple i386-pc-win32 %s -emit-llvm -fms-compatibility -o - | FileCheck %s
+__declspec(selectany) int x1 = 1;
+const __declspec(selectany) int x2 = 2;
+// CHECK: @x1 = weak_odr global i32 1, align 4
+// CHECK: @x2 = weak_odr constant i32 2, align 4
+
struct __declspec(align(16)) S {
char x;
};