From 06c0167a16cfa5e2b063bf60bf70c074a794b44d Mon Sep 17 00:00:00 2001
From: Fariborz Jahanian <fjahanian@apple.com>
Date: Mon, 3 Mar 2014 21:53:57 +0000
Subject: [PATCH] Objective-C. Fixes a regression when figuring out linkage for
 metadata symbols for forward referenced protocols which are never defined. 
 // rdar://16203115

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@202761 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGObjCMac.cpp                     |  3 ++-
 .../forward-protocol-metadata-symbols.m       | 24 +++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 test/CodeGenObjC/forward-protocol-metadata-symbols.m

diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 044bc18c1e..7f2432c08c 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -2660,6 +2660,7 @@ llvm::Constant *CGObjCMac::GetOrEmitProtocol(const ObjCProtocolDecl *PD) {
 
   if (Entry) {
     // Already created, fix the linkage and update the initializer.
+    Entry->setLinkage(llvm::GlobalValue::PrivateLinkage);
     Entry->setInitializer(Init);
   } else {
     Entry =
@@ -6357,7 +6358,7 @@ llvm::Constant *CGObjCNonFragileABIMac::GetOrEmitProtocol(
 
   if (Entry) {
     // Already created, fix the linkage and update the initializer.
-    assert(Entry->getLinkage() == llvm::GlobalValue::WeakAnyLinkage);
+    Entry->setLinkage(llvm::GlobalValue::WeakAnyLinkage);
     Entry->setInitializer(Init);
   } else {
     Entry =
diff --git a/test/CodeGenObjC/forward-protocol-metadata-symbols.m b/test/CodeGenObjC/forward-protocol-metadata-symbols.m
new file mode 100644
index 0000000000..c28adb3f8a
--- /dev/null
+++ b/test/CodeGenObjC/forward-protocol-metadata-symbols.m
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -emit-llvm -x objective-c %s -o - | FileCheck %s
+// rdar://16203115
+
+@interface NSObject @end
+
+@protocol P0;
+
+@interface A : NSObject <P0>
++(Class) getClass;
+@end
+
+@implementation A
++(Class) getClass { return self; }
+@end
+
+int main() {
+  Protocol *P0 = @protocol(P0);
+  return 0;
+}
+
+// CHECK: @"\01l_OBJC_PROTOCOL_$_P0" = weak hidden global
+// CHECK: @"\01l_OBJC_CLASS_PROTOCOLS_$_A" = private global
+// CHECK: @"\01l_OBJC_LABEL_PROTOCOL_$_P0" = weak hidden global
+// CHECK: @"\01l_OBJC_PROTOCOL_REFERENCE_$_P0" = weak hidden global
-- 
2.40.0