Add 'thinlto_src_module' md with asserts or -enable-import-metadata

Summary:
This way the metadata will be only generated when asserts enabled,
or when -enable-import-metadata specified

Reviewers: tejohnson, eraman, mehdi_amini

Subscribers: mehdi_amini, llvm-commits

Differential Revision: http://reviews.llvm.org/D22167

llvm-svn: 274938

1 files changed, 19 insertions, 6 deletions

diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index f15d8cff6d9..c9d075e7632 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -58,6 +58,16 @@ static cl::opt<bool>
     DontForceImportReferencedDiscardableSymbols("disable-force-link-odr",
                                                 cl::init(false), cl::Hidden);
 
+static cl::opt<bool> EnableImportMetadata(
+    "enable-import-metadata", cl::init(
+#if !defined(NDEBUG)
+                                  true /*Enabled with asserts.*/
+#else
+                                  false
+#endif
+                                  ),
+    cl::Hidden, cl::desc("Enable import metadata like 'thinlto_src_module'"));
+
 // Load lazily a module from \p FileName in \p Context.
 static std::unique_ptr<Module> loadFile(const std::string &FileName,
                                         LLVMContext &Context) {
@@ -591,12 +601,15 @@ 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())}));
+        if (EnableImportMetadata) {
+          // 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);
       }
     }