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.

llvm-svn: 97733

3 files changed, 108 insertions, 6 deletions

diff --git a/clang/test/CodeGen/attr-weakref.c b/clang/test/CodeGen/attr-weakref.c
new file mode 100644
index 00000000000..06185e8e34e
--- /dev/null
+++ b/clang/test/CodeGen/attr-weakref.c
@@ -0,0 +1,54 @@
+// RUN: %clang_cc1 -emit-llvm -triple i386-linux-gnu -o %t %s
+// RUN: FileCheck --input-file=%t %s
+
+// CHECK: declare extern_weak void @test1_f()
+void test1_f(void);
+static void test1_g(void) __attribute__((weakref("test1_f")));
+void test1_h(void) {
+  test1_g();
+}
+
+// CHECK: define void @test2_f()
+void test2_f(void) {}
+static void test2_g(void) __attribute__((weakref("test2_f")));
+void test2_h(void) {
+  test2_g();
+}
+
+// CHECK: declare void @test3_f()
+void test3_f(void);
+static void test3_g(void) __attribute__((weakref("test3_f")));
+void test3_foo(void) {
+  test3_f();
+}
+void test3_h(void) {
+  test3_g();
+}
+
+// CHECK: define void @test4_f()
+void test4_f(void);
+static void test4_g(void) __attribute__((weakref("test4_f")));
+void test4_h(void) {
+  test4_g();
+}
+void test4_f(void) {}
+
+// CHECK: declare void @test5_f()
+void test5_f(void);
+static void test5_g(void) __attribute__((weakref("test5_f")));
+void test5_h(void) {
+  test5_g();
+}
+void test5_foo(void) {
+  test5_f();
+}
+
+// CHECK: declare extern_weak void @test6_f()
+void test6_f(void) __attribute__((weak));
+static void test6_g(void) __attribute__((weakref("test6_f")));
+void test6_h(void) {
+  test6_g();
+}
+void test6_foo(void) {
+  test6_f();
+}
diff --git a/clang/test/CodeGen/attr-weakref2.c b/clang/test/CodeGen/attr-weakref2.c
new file mode 100644
index 00000000000..99760635581
--- /dev/null
+++ b/clang/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;
+}
diff --git a/clang/test/CodeGen/attributes.c b/clang/test/CodeGen/attributes.c
index 4fdf1a51762..770ce766dfb 100644
--- a/clang/test/CodeGen/attributes.c
+++ b/clang/test/CodeGen/attributes.c
@@ -30,12 +30,6 @@ int t12 __attribute__((section("SECT")));
 void __t8() {}
 void t9() __attribute__((weak, alias("__t8")));
 
-static void t22(void) __attribute__((weakref("t8")));
-// CHECK: @t22 = alias weak void ()* @t8
-
-static void t23(void) __attribute__((weakref, alias("t8")));
-// CHECK: @t23 = alias weak void ()* @t8
-
 // CHECK: declare extern_weak i32 @t15()
 int __attribute__((weak_import)) t15(void);
 int t17() {