From c40d5a1d2a4582c1caee9b49462a66eb0a08c7bd Mon Sep 17 00:00:00 2001
From: Evgeniy Stepanov <eugeni.stepanov@gmail.com>
Date: Thu, 4 May 2017 23:29:39 +0000
Subject: [PATCH] Remap metadata attached to global variables.

Fix for PR32577.
Global variables may have !associated metadata, which includes a reference to another global. It needs remapping.

llvm-svn: 302203
---
 lib/Transforms/Utils/ValueMapper.cpp | 17 ++++++++++++-----
 test/Linker/metadata-global.ll       | 11 +++++++++++
 2 files changed, 23 insertions(+), 5 deletions(-)
 create mode 100644 test/Linker/metadata-global.ll

diff --git a/lib/Transforms/Utils/ValueMapper.cpp b/lib/Transforms/Utils/ValueMapper.cpp
index f77c10b6dd4..84d89f103a2 100644
--- a/lib/Transforms/Utils/ValueMapper.cpp
+++ b/lib/Transforms/Utils/ValueMapper.cpp
@@ -121,6 +121,8 @@ public:
 
   void addFlags(RemapFlags Flags);
 
+  void remapGlobalObjectMetadata(GlobalObject &GO);
+
   Value *mapValue(const Value *V);
   void remapInstruction(Instruction *I);
   void remapFunction(Function &F);
@@ -802,6 +804,7 @@ void Mapper::flush() {
     switch (E.Kind) {
     case WorklistEntry::MapGlobalInit:
       E.Data.GVInit.GV->setInitializer(mapConstant(E.Data.GVInit.Init));
+      remapGlobalObjectMetadata(*E.Data.GVInit.GV);
       break;
     case WorklistEntry::MapAppendingVar: {
       unsigned PrefixSize = AppendingInits.size() - E.AppendingGVNumNewMembers;
@@ -892,6 +895,14 @@ void Mapper::remapInstruction(Instruction *I) {
   I->mutateType(TypeMapper->remapType(I->getType()));
 }
 
+void Mapper::remapGlobalObjectMetadata(GlobalObject &GO) {
+  SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
+  GO.getAllMetadata(MDs);
+  GO.clearMetadata();
+  for (const auto &I : MDs)
+    GO.addMetadata(I.first, *cast<MDNode>(mapMetadata(I.second)));
+}
+
 void Mapper::remapFunction(Function &F) {
   // Remap the operands.
   for (Use &Op : F.operands())
@@ -899,11 +910,7 @@ void Mapper::remapFunction(Function &F) {
       Op = mapValue(Op);
 
   // Remap the metadata attachments.
-  SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
-  F.getAllMetadata(MDs);
-  F.clearMetadata();
-  for (const auto &I : MDs)
-    F.addMetadata(I.first, *cast<MDNode>(mapMetadata(I.second)));
+  remapGlobalObjectMetadata(F);
 
   // Remap the argument types.
   if (TypeMapper)
diff --git a/test/Linker/metadata-global.ll b/test/Linker/metadata-global.ll
new file mode 100644
index 00000000000..56d77e128bd
--- /dev/null
+++ b/test/Linker/metadata-global.ll
@@ -0,0 +1,11 @@
+; RUN: llvm-link %s -S | FileCheck %s
+
+; CHECK-DAG: @a = global i32 0
+; CHECK-DAG: @b = global i32 0, !associated !0
+
+; CHECK-DAG: !0 = !{i32* @b}
+
+@a = global i32 0
+@b = global i32 0, !associated !0
+
+!0 = !{i32* @b}