Restore "Move metadata linking after lazy global materialization/linking."

This reverts commit r251965.

llvm-svn: 252319

3 files changed, 34 insertions, 9 deletions

diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index 4a12633c305..74ca197ddb3 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -1892,15 +1892,6 @@ bool ModuleLinker::run() {
     linkGlobalValueBody(Src);
   }
 
-  // Remap all of the named MDNodes in Src into the DstM module. We do this
-  // after linking GlobalValues so that MDNodes that reference GlobalValues
-  // are properly remapped.
-  linkNamedMDNodes();
-
-  // Merge the module flags into the DstM module.
-  if (linkModuleFlagsMetadata())
-    return true;
-
   // Update the initializers in the DstM module now that all globals that may
   // be referenced are in DstM.
   for (GlobalVariable &Src : SrcM->globals()) {
@@ -1927,6 +1918,15 @@ bool ModuleLinker::run() {
       return true;
   }
 
+  // Remap all of the named MDNodes in Src into the DstM module. We do this
+  // after linking GlobalValues so that MDNodes that reference GlobalValues
+  // are properly remapped.
+  linkNamedMDNodes();
+
+  // Merge the module flags into the DstM module.
+  if (linkModuleFlagsMetadata())
+    return true;
+
   return false;
 }
 
diff --git a/llvm/test/Linker/Inputs/only-needed-named-metadata.ll b/llvm/test/Linker/Inputs/only-needed-named-metadata.ll
new file mode 100644
index 00000000000..fa7bc2e3cc8
--- /dev/null
+++ b/llvm/test/Linker/Inputs/only-needed-named-metadata.ll
@@ -0,0 +1,9 @@
+@X = external global i32
+
+declare i32 @foo()
+
+define void @bar() {
+	load i32, i32* @X
+	call i32 @foo()
+	ret void
+}
diff --git a/llvm/test/Linker/only-needed-named-metadata.ll b/llvm/test/Linker/only-needed-named-metadata.ll
new file mode 100644
index 00000000000..f64637d3c75
--- /dev/null
+++ b/llvm/test/Linker/only-needed-named-metadata.ll
@@ -0,0 +1,16 @@
+; RUN: llvm-as %S/only-needed-named-metadata.ll -o %t.bc
+; RUN: llvm-as %S/Inputs/only-needed-named-metadata.ll -o %t2.bc
+; RUN: llvm-link -S -only-needed %t2.bc %t.bc | FileCheck %s
+; RUN: llvm-link -S -internalize -only-needed %t2.bc %t.bc | FileCheck %s
+
+; CHECK: @U = external global i32
+; CHECK: declare i32 @unused()
+
+@X = global i32 5
+@U = global i32 6
+define i32 @foo() { ret i32 7 }
+define i32 @unused() { ret i32 8 }
+
+!llvm.named = !{!0, !1}
+!0 = !{i32 ()* @unused}
+!1 = !{i32* @U}