Fix PR6473.

Clang's support for weakref is now better than llvm-gcc's :-)

We don't introduce a new symbol and we correctly mark undefined references weak only if there is no
definition or regular undefined references in the same file.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@97733 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/attr-weakref2.c b/test/CodeGen/attr-weakref2.c
new file mode 100644
index 0000000..9976063
--- /dev/null
+++ b/test/CodeGen/attr-weakref2.c
@@ -0,0 +1,54 @@
+// RUN: %clang_cc1 -emit-llvm -triple i386-linux-gnu -o %t %s
+// RUN: FileCheck --input-file=%t %s
+
+// CHECK: @test1_f = extern_weak global i32
+extern int test1_f;
+static int test1_g __attribute__((weakref("test1_f")));
+int test1_h(void) {
+  return test1_g;
+}
+
+// CHECK: @test2_f = common global i32 0, align 4
+int test2_f;
+static int test2_g __attribute__((weakref("test2_f")));
+int test2_h(void) {
+  return test2_g;
+}
+
+// CHECK: @test3_f = external global i32
+extern int test3_f;
+static int test3_g __attribute__((weakref("test3_f")));
+int test3_foo(void) {
+  return test3_f;
+}
+int test3_h(void) {
+  return test3_g;
+}
+
+// CHECK: @test4_f = common global i32 0, align 4
+extern int test4_f;
+static int test4_g __attribute__((weakref("test4_f")));
+int test4_h(void) {
+  return test4_g;
+}
+int test4_f;
+
+// CHECK: @test5_f = external global i32
+extern int test5_f;
+static int test5_g __attribute__((weakref("test5_f")));
+int test5_h(void) {
+  return test5_g;
+}
+int test5_foo(void) {
+  return test5_f;
+}
+
+// CHECK: @test6_f = extern_weak global i32
+extern int test6_f __attribute__((weak));
+static int test6_g __attribute__((weakref("test6_f")));
+int test6_h(void) {
+  return test6_g;
+}
+int test6_foo(void) {
+  return test6_f;
+}