From 269f8bc10a33e29e2951df7720cad0abb45c74cb Mon Sep 17 00:00:00 2001
From: Fariborz Jahanian <fjahanian@apple.com>
Date: Tue, 17 Nov 2009 22:42:00 +0000
Subject: [PATCH] This patch finalizes implementatin of weak_import
 objective-c2 classes (radar 6815425).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89157 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGObjCMac.cpp                     |  6 ++++
 .../CodeGenObjC/objc2-weak-import-attribute.m | 34 +++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 test/CodeGenObjC/objc2-weak-import-attribute.m

diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 2a89620ce9..4355e66fee 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -5243,6 +5243,12 @@ llvm::Value *CGObjCNonFragileABIMac::EmitMetaClassRef(CGBuilderTy &Builder,
 /// decl.
 llvm::Value *CGObjCNonFragileABIMac::GetClass(CGBuilderTy &Builder,
                                               const ObjCInterfaceDecl *ID) {
+  if (ID->hasAttr<WeakImportAttr>()) {
+    std::string ClassName(getClassSymbolPrefix() + ID->getNameAsString());
+    llvm::GlobalVariable *ClassGV = GetClassGlobal(ClassName);
+    ClassGV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
+  }
+  
   return EmitClassRef(Builder, ID);
 }
 
diff --git a/test/CodeGenObjC/objc2-weak-import-attribute.m b/test/CodeGenObjC/objc2-weak-import-attribute.m
new file mode 100644
index 0000000000..4a5f14e2e0
--- /dev/null
+++ b/test/CodeGenObjC/objc2-weak-import-attribute.m
@@ -0,0 +1,34 @@
+// RUN: clang-cc -fobjc-nonfragile-abi -triple x86_64-apple-darwin10 -emit-llvm -o - %s | FileCheck -check-prefix=CHECK-X86-64 %s
+
+__attribute__((weak_import)) @interface WeakClass 
+@end
+
+@interface MySubclass : WeakClass @end
+
+@implementation MySubclass @end
+
+@implementation WeakClass(MyCategory) @end
+
+
+__attribute__((weak_import))
+@interface WeakClass1 @end
+
+@implementation WeakClass1(MyCategory) @end
+
+@implementation WeakClass1(YourCategory) @end
+
+ __attribute__((weak_import))
+@interface WeakClass3 
++ message;
+@end
+
+int main() {
+     [WeakClass3 message];
+}
+
+// CHECK-X86-64: OBJC_METACLASS_$_WeakClass" = extern_weak global
+// CHECK-X86-64: OBJC_CLASS_$_WeakClass" = extern_weak global
+// CHECK-X86-64: OBJC_CLASS_$_WeakClass1" = extern_weak global
+// CHECK-X86-64: OBJC_CLASS_$_WeakClass3" = extern_weak global
+
+
-- 
2.50.1