2 files changed, 29 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 1026c9d3703..75e8963303c 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -210,6 +210,21 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
       RemapInstruction(&II, VMap,
                        ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
                        TypeMapper, Materializer);
+
+  // Register all DICompileUnits of the old parent module in the new parent module
+  auto* OldModule = OldFunc->getParent();
+  auto* NewModule = NewFunc->getParent();
+  if (OldModule && NewModule && OldModule != NewModule && DIFinder.compile_unit_count()) {
+    auto* NMD = NewModule->getOrInsertNamedMetadata("llvm.dbg.cu");
+    // Avoid multiple insertions of the same DICompileUnit to NMD.
+    SmallPtrSet<const void*, 8> Visited;
+    for (auto* Operand : NMD->operands())
+      Visited.insert(Operand);
+    for (auto* Unit : DIFinder.compile_units())
+      // VMap.MD()[Unit] == Unit
+      if (Visited.insert(Unit).second)
+        NMD->addOperand(Unit);
+  }
 }
 
 /// Return a copy of the specified function and add it to that function's
diff --git a/llvm/lib/Transforms/Utils/CloneModule.cpp b/llvm/lib/Transforms/Utils/CloneModule.cpp
index 71e39e9f56f..2c8c3abb292 100644
--- a/llvm/lib/Transforms/Utils/CloneModule.cpp
+++ b/llvm/lib/Transforms/Utils/CloneModule.cpp
@@ -181,13 +181,25 @@ std::unique_ptr<Module> llvm::CloneModule(
   }
 
   // And named metadata....
+  const auto* LLVM_DBG_CU = M.getNamedMetadata("llvm.dbg.cu");
   for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
                                              E = M.named_metadata_end();
        I != E; ++I) {
     const NamedMDNode &NMD = *I;
     NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
-    for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
-      NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
+    if (&NMD == LLVM_DBG_CU) {
+      // Do not insert duplicate operands.
+      SmallPtrSet<const void*, 8> Visited;
+      for (const auto* Operand : NewNMD->operands())
+        Visited.insert(Operand);
+      for (const auto* Operand : NMD.operands()) {
+        auto* MappedOperand = MapMetadata(Operand, VMap);
+        if (Visited.insert(MappedOperand).second)
+          NewNMD->addOperand(MappedOperand);
+      }
+    } else
+      for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
+        NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
   }
 
   return New;