From 8eb026ceb620a60b5436b0fb5a84533d0d4040f1 Mon Sep 17 00:00:00 2001
From: Adrian Prantl <aprantl@apple.com>
Date: Mon, 15 Jun 2015 23:18:16 +0000
Subject: [PATCH] Debug Info: Turn on ODR type uniquing for (the C++ part of)
 Objective-C++.

rdar://problem/20571359

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@239781 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGDebugInfo.cpp             | 19 +++++++++++++++----
 test/CodeGenObjCXX/debug-info-cyclic.mm |  3 ++-
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 48458dbd60..a20e39f3fc 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -590,18 +590,29 @@ llvm::DIType *CGDebugInfo::CreateType(const PointerType *Ty,
                                Ty->getPointeeType(), Unit);
 }
 
+/// \return whether a C++ mangling exists for the type defined by TD.
+static bool hasCXXMangling(const TagDecl *TD, llvm::DICompileUnit *TheCU) {
+  switch (TheCU->getSourceLanguage()) {
+  case llvm::dwarf::DW_LANG_C_plus_plus:
+    return true;
+  case llvm::dwarf::DW_LANG_ObjC_plus_plus:
+    return isa<CXXRecordDecl>(TD) || isa<EnumDecl>(TD);
+  default:
+    return false;
+  }
+}
+
 /// In C++ mode, types have linkage, so we can rely on the ODR and
 /// on their mangled names, if they're external.
 static SmallString<256> getUniqueTagTypeName(const TagType *Ty,
                                              CodeGenModule &CGM,
                                              llvm::DICompileUnit *TheCU) {
   SmallString<256> FullName;
-  // FIXME: ODR should apply to ObjC++ exactly the same wasy it does to C++.
-  // For now, only apply ODR with C++.
   const TagDecl *TD = Ty->getDecl();
-  if (TheCU->getSourceLanguage() != llvm::dwarf::DW_LANG_C_plus_plus ||
-      !TD->isExternallyVisible())
+
+  if (!hasCXXMangling(TD, TheCU) || !TD->isExternallyVisible())
     return FullName;
+
   // Microsoft Mangler does not have support for mangleCXXRTTIName yet.
   if (CGM.getTarget().getCXXABI().isMicrosoft())
     return FullName;
diff --git a/test/CodeGenObjCXX/debug-info-cyclic.mm b/test/CodeGenObjCXX/debug-info-cyclic.mm
index 8983fe5112..37a8064baa 100644
--- a/test/CodeGenObjCXX/debug-info-cyclic.mm
+++ b/test/CodeGenObjCXX/debug-info-cyclic.mm
@@ -1,12 +1,13 @@
 // RUN: %clang_cc1 -triple x86_64-apple-darwin -g -emit-llvm %s -o - | FileCheck %s
 
 struct B {
-// CHECK: ![[B:[0-9]+]] = !DICompositeType(tag: DW_TAG_structure_type, name: "B"
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "B"
 // CHECK-SAME:                             line: [[@LINE-2]],
 // CHECK-SAME:                             size: 8, align: 8,
 // CHECK-NOT:                              offset:
 // CHECK-NOT:                              DIFlagFwdDecl
 // CHECK-SAME:                             elements: ![[BMEMBERS:[0-9]+]]
+// CHECK-SAME:                             identifier: [[B:.*]])
 // CHECK: ![[BMEMBERS]] = !{![[BB:[0-9]+]]}
   B(struct A *);
 // CHECK: ![[BB]] = !DISubprogram(name: "B", scope: ![[B]]
-- 
2.40.0