1 files changed, 6 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index f756a2978d4..f15d8cff6d9 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -591,6 +591,12 @@ bool FunctionImporter::importFunctions(
                    << SrcModule->getSourceFileName() << "\n");
       if (Import) {
         F.materialize();
+        // Add 'thinlto_src_module' metadata for statistics and debugging.
+        F.setMetadata("thinlto_src_module",
+                      llvm::MDNode::get(DestModule.getContext(),
+                                        {llvm::MDString::get(
+                                            DestModule.getContext(),
+                                            SrcModule->getSourceFileName())}));
         GlobalsToImport.insert(&F);
       }
     }