Link NamedMDNodes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78696 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Metadata.h

@@ -229,6 +229,8 @@ public:
     return new NamedMDNode(N, MDs, NumMDs, M);
   }
 
+  static NamedMDNode *Create(const NamedMDNode *NMD, Module *M = 0);
+
   /// eraseFromParent - Drop all references and remove the node from parent
   /// module.
   void eraseFromParent();

lib/Linker/LinkModules.cpp

@@ -538,6 +538,22 @@ static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
   return false;
 }
 
+// Insert all of the named mdnoes in Src into the Dest module.
+static void LinkNamedMDNodes(Module *Dest, Module *Src) {
+  for (Module::const_named_metadata_iterator I = Src->named_metadata_begin(),
+         E = Src->named_metadata_end(); I != E; ++I) {
+    const NamedMDNode *SrcNMD = I;
+    NamedMDNode *DestNMD = Dest->getNamedMetadata(SrcNMD->getName());
+    if (!DestNMD)
+      NamedMDNode::Create(SrcNMD, Dest);
+    else {
+      // Add Src elements into Dest node.
+      for (unsigned i = 0, e = SrcNMD->getNumElements(); i != e; ++i) 
+        DestNMD->addElement(SrcNMD->getElement(i));
+    }
+  }
+}
+
 // LinkGlobals - Loop through the global variables in the src module and merge
 // them into the dest module.
 static bool LinkGlobals(Module *Dest, const Module *Src,
@@ -1307,6 +1323,9 @@ Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
       AppendingVars.insert(std::make_pair(I->getName(), I));
   }
 
+  // Insert all of the named mdnoes in Src into the Dest module.
+  LinkNamedMDNodes(Dest, Src);
+
   // Insert all of the globals in src into the Dest module... without linking
   // initializers (which could refer to functions not yet mapped over).
   if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))

lib/VMCore/Metadata.cpp

@@ -104,6 +104,7 @@ MDNode::~MDNode() {
   dropAllReferences();
   getType()->getContext().pImpl->MDNodes.remove(this);
 }
+
 //===----------------------------------------------------------------------===//
 //NamedMDNode implementation
 //
@@ -123,6 +124,14 @@ NamedMDNode::NamedMDNode(const Twine &N, MetadataBase*const* MDs,
     ParentModule->getNamedMDList().push_back(this);
 }
 
+NamedMDNode *NamedMDNode::Create(const NamedMDNode *NMD, Module *M) {
+  assert (NMD && "Invalid source NamedMDNode!");
+  SmallVector<MetadataBase *, 4> Elems;
+  for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i)
+    Elems.push_back(NMD->getElement(i));
+  return new NamedMDNode(NMD->getName().data(), Elems.data(), Elems.size(), M);
+}
+
 /// eraseFromParent - Drop all references and remove the node from parent
 /// module.
 void NamedMDNode::eraseFromParent() {

test/Linker/linknamedmdnode.ll

@@ -0,0 +1,6 @@
+; RUN: llvm-as < %s > %t.bc
+; RUN: llvm-as < %p/linknamedmdnode2.ll > %t2.bc
+; RUN: llvm-link %t.bc %t2.bc | llvm-dis | grep "!llvm.stuff = !{!0, !1}"
+
+!0 = metadata !{i32 42}
+!llvm.stuff = !{!0}

test/Linker/linknamedmdnode2.ll

@@ -0,0 +1,6 @@
+; This file is used by linknamedmdnode.ll, so it doesn't actually do anything itself
+;
+; RUN: true
+
+!0 = metadata !{i32 41}
+!llvm.stuff = !{!0}