1 files changed, 28 insertions, 5 deletions
diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index 9c9c0ef321f..556251092a2 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -48,6 +48,11 @@ class ModuleLinker {
   /// as part of a different backend compilation process.
   bool HasExportedFunctions = false;
 
+  /// Association between metadata value id and temporary metadata that
+  /// remains unmapped after function importing. Saved during function
+  /// importing and consumed during the metadata linking postpass.
+  DenseMap<unsigned, MDNode *> *ValIDToTempMDMap;
+
   /// Used as the callback for lazy linking.
   /// The mover has just hit GV and we have to decide if it, and other members
   /// of the same comdat, should be linked. Every member to be linked is passed
@@ -150,9 +155,10 @@ class ModuleLinker {
 public:
   ModuleLinker(IRMover &Mover, Module &SrcM, unsigned Flags,
                const FunctionInfoIndex *Index = nullptr,
-               DenseSet<const GlobalValue *> *FunctionsToImport = nullptr)
+               DenseSet<const GlobalValue *> *FunctionsToImport = nullptr,
+               DenseMap<unsigned, MDNode *> *ValIDToTempMDMap = nullptr)
       : Mover(Mover), SrcM(SrcM), Flags(Flags), ImportIndex(Index),
-        ImportFunction(FunctionsToImport) {
+        ImportFunction(FunctionsToImport), ValIDToTempMDMap(ValIDToTempMDMap) {
     assert((ImportIndex || !ImportFunction) &&
            "Expect a FunctionInfoIndex when importing");
     // If we have a FunctionInfoIndex but no function to import,
@@ -161,6 +167,8 @@ public:
     // may be exported to another backend compilation.
     if (ImportIndex && !ImportFunction)
       HasExportedFunctions = ImportIndex->hasExportedFunctions(SrcM);
+    assert((ValIDToTempMDMap || !ImportFunction) &&
+           "Function importing must provide a ValIDToTempMDMap");
   }
 
   bool run();
@@ -502,6 +510,7 @@ bool ModuleLinker::getComdatResult(const Comdat *SrcC,
 bool ModuleLinker::shouldLinkFromSource(bool &LinkFromSrc,
                                         const GlobalValue &Dest,
                                         const GlobalValue &Src) {
+
   // Should we unconditionally use the Src?
   if (shouldOverrideFromSrc()) {
     LinkFromSrc = true;
@@ -776,7 +785,8 @@ bool ModuleLinker::run() {
   if (Mover.move(SrcM, ValuesToLink.getArrayRef(),
                  [this](GlobalValue &GV, IRMover::ValueAdder Add) {
                    addLazyFor(GV, Add);
-                 }))
+                 },
+                 ValIDToTempMDMap, false))
     return true;
   Module &DstM = Mover.getModule();
   for (auto &P : Internalize) {
@@ -791,8 +801,10 @@ Linker::Linker(Module &M) : Mover(M) {}
 
 bool Linker::linkInModule(std::unique_ptr<Module> Src, unsigned Flags,
                           const FunctionInfoIndex *Index,
-                          DenseSet<const GlobalValue *> *FunctionsToImport) {
-  ModuleLinker TheLinker(Mover, *Src, Flags, Index, FunctionsToImport);
+                          DenseSet<const GlobalValue *> *FunctionsToImport,
+                          DenseMap<unsigned, MDNode *> *ValIDToTempMDMap) {
+  ModuleLinker TheLinker(Mover, *Src, Flags, Index, FunctionsToImport,
+                         ValIDToTempMDMap);
   return TheLinker.run();
 }
 
@@ -801,6 +813,17 @@ bool Linker::linkInModuleForCAPI(Module &Src) {
   return TheLinker.run();
 }
 
+bool Linker::linkInMetadata(Module &Src,
+                            DenseMap<unsigned, MDNode *> *ValIDToTempMDMap) {
+  SetVector<GlobalValue *> ValuesToLink;
+  if (Mover.move(
+          Src, ValuesToLink.getArrayRef(),
+          [this](GlobalValue &GV, IRMover::ValueAdder Add) { assert(false); },
+          ValIDToTempMDMap, true))
+    return true;
+  return false;
+}
+
 //===----------------------------------------------------------------------===//
 // LinkModules entrypoint.
 //===----------------------------------------------------------------------===//