From 9f83f3b2511d6b7b396d9f98a7cda4dab4d42a34 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Thu, 29 Jun 2017 00:54:44 +0000
Subject: [PATCH] CodeGen: handle missed case of COMDAT handling

When Protocol references are constructed, we need to add the reference
symbol to a COMDAT group on non-MachO object file formats (MachO handles
this by having a coalesced attribute).  This adds the missing case.

llvm-svn: 306622
---
 clang/lib/CodeGen/CGObjCMac.cpp          | 11 +++++------
 clang/test/CodeGenObjC/protocol-comdat.m |  8 ++++++++
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index 7976c53d9e98..224d2d6606a2 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -6381,16 +6381,15 @@ llvm::Value *CGObjCNonFragileABIMac::GenerateProtocolRef(CodeGenFunction &CGF,
   llvm::GlobalVariable *PTGV = CGM.getModule().getGlobalVariable(ProtocolName);
   if (PTGV)
     return CGF.Builder.CreateAlignedLoad(PTGV, Align);
-  PTGV = new llvm::GlobalVariable(
-    CGM.getModule(),
-    Init->getType(), false,
-    llvm::GlobalValue::WeakAnyLinkage,
-    Init,
-    ProtocolName);
+  PTGV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(), false,
+                                  llvm::GlobalValue::WeakAnyLinkage, Init,
+                                  ProtocolName);
   PTGV->setSection(GetSectionName("__objc_protorefs",
                                   "coalesced,no_dead_strip"));
   PTGV->setVisibility(llvm::GlobalValue::HiddenVisibility);
   PTGV->setAlignment(Align.getQuantity());
+  if (!CGM.getTriple().isOSBinFormatMachO())
+    PTGV->setComdat(CGM.getModule().getOrInsertComdat(ProtocolName));
   CGM.addCompilerUsedGlobal(PTGV);
   return CGF.Builder.CreateAlignedLoad(PTGV, Align);
 }
diff --git a/clang/test/CodeGenObjC/protocol-comdat.m b/clang/test/CodeGenObjC/protocol-comdat.m
index 65e1b9fa2c82..a19ba8cf35dc 100644
--- a/clang/test/CodeGenObjC/protocol-comdat.m
+++ b/clang/test/CodeGenObjC/protocol-comdat.m
@@ -4,6 +4,9 @@
 - (void) method;
 @end
 
+@protocol Q;
+@protocol R;
+
 @interface I<P>
 @end
 
@@ -11,9 +14,14 @@
 - (void) method { }
 @end
 
+_Bool f(void) {
+  return @protocol(Q) == @protocol(R);
+}
 
 // CHECK: $"\01l_OBJC_PROTOCOL_$_P" = comdat any
 // CHECK: $"\01l_OBJC_LABEL_PROTOCOL_$_P" = comdat any
+// CHECK: $"\01l_OBJC_PROTOCOL_REFERENCE_$_Q" = comdat any
+// CHECK: $"\01l_OBJC_PROTOCOL_REFERENCE_$_R" = comdat any
 
 // CHECK: @"\01l_OBJC_PROTOCOL_$_P" = {{.*}}, comdat
 // CHECK: @"\01l_OBJC_LABEL_PROTOCOL_$_P" = {{.*}}, comdat