From 9cabb129a0216bab9fd4e56b0b79fa3342ddda05 Mon Sep 17 00:00:00 2001
From: "Duncan P. N. Exon Smith" <dexonsmith@apple.com>
Date: Fri, 24 Apr 2015 22:07:31 +0000
Subject: [PATCH] Linker: Copy over function metadata attachments

Update `lib/Linker` to handle `Function` metadata attachments.  The
attachments stick with the function body.

llvm-svn: 235786
---
 lib/Linker/LinkModules.cpp              |  7 +++++++
 test/Linker/Inputs/metadata-function.ll | 13 +++++++++++++
 test/Linker/metadata-function.ll        | 26 +++++++++++++++++++++++++
 3 files changed, 46 insertions(+)
 create mode 100644 test/Linker/Inputs/metadata-function.ll
 create mode 100644 test/Linker/metadata-function.ll

diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 65a02a71c70..34a353a6c82 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -1205,6 +1205,13 @@ bool ModuleLinker::linkFunctionBody(Function &Dst, Function &Src) {
     ++DI;
   }
 
+  // Copy over the metadata attachments.
+  SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
+  Src.getAllMetadata(MDs);
+  for (const auto &I : MDs)
+    Dst.setMetadata(I.first, MapMetadata(I.second, ValueMap, RF_None, &TypeMap,
+                                         &ValMaterializer));
+
   // Splice the body of the source function into the dest function.
   Dst.getBasicBlockList().splice(Dst.end(), Src.getBasicBlockList());
 
diff --git a/test/Linker/Inputs/metadata-function.ll b/test/Linker/Inputs/metadata-function.ll
new file mode 100644
index 00000000000..8572ff11983
--- /dev/null
+++ b/test/Linker/Inputs/metadata-function.ll
@@ -0,0 +1,13 @@
+define weak void @foo() !weak !0 {
+  unreachable
+}
+
+define void @baz() !baz !0 {
+  unreachable
+}
+
+define void @b() !b !0 {
+  unreachable
+}
+
+!0 = !{!"b"}
diff --git a/test/Linker/metadata-function.ll b/test/Linker/metadata-function.ll
new file mode 100644
index 00000000000..0b17e0c5858
--- /dev/null
+++ b/test/Linker/metadata-function.ll
@@ -0,0 +1,26 @@
+; RUN: llvm-link %s %S/Inputs/metadata-function.ll -S | FileCheck %s
+; RUN: llvm-link %S/Inputs/metadata-function.ll %s -S | FileCheck %s
+
+; CHECK-DAG: define weak void @foo() !weak ![[B:[0-9]+]] {
+define linkonce void @foo() !linkonce !0 {
+  unreachable
+}
+
+; CHECK-DAG: define void @bar() !bar ![[A:[0-9]+]] {
+define void @bar() !bar !0 {
+  call void @baz()
+  unreachable
+}
+
+; CHECK-DAG: define void @baz() !baz ![[B]] {
+declare void @baz()
+
+; CHECK-DAG: define void @a() !a ![[A]] {
+; CHECK-DAG: define void @b() !b ![[B]] {
+define void @a() !a !0 {
+  unreachable
+}
+
+; CHECK-DAG: ![[A]] = !{!"a"}
+; CHECK-DAG: ![[B]] = !{!"b"}
+!0 = !{!"a"}