1 files changed, 10 insertions, 1 deletions
diff --git a/lib/LTO/LTO.cpp b/lib/LTO/LTO.cpp
index 68b8c9fcb939..19973946ac5a 100644
--- a/lib/LTO/LTO.cpp
+++ b/lib/LTO/LTO.cpp
@@ -665,6 +665,15 @@ Error LTO::addThinLTO(BitcodeModule BM, ArrayRef<InputFile::Symbol> Syms,
         auto GUID = GlobalValue::getGUID(GlobalValue::getGlobalIdentifier(
             Sym.getIRName(), GlobalValue::ExternalLinkage, ""));
         ThinLTO.PrevailingModuleForGUID[GUID] = BM.getModuleIdentifier();
+
+        // For linker redefined symbols (via --wrap or --defsym) we want to
+        // switch the linkage to `weak` to prevent IPOs from happening.
+        // Find the summary in the module for this very GV and record the new
+        // linkage so that we can switch it when we import the GV.
+        if (Res.LinkerRedefined)
+          if (auto S = ThinLTO.CombinedIndex.findSummaryInModule(
+                  GUID, BM.getModuleIdentifier()))
+            S->setLinkage(GlobalValue::WeakAnyLinkage);
       }
     }
   }
@@ -1021,7 +1030,7 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
 
   // Collect for each module the list of function it defines (GUID ->
   // Summary).
-  StringMap<std::map<GlobalValue::GUID, GlobalValueSummary *>>
+  StringMap<GVSummaryMapTy>
       ModuleToDefinedGVSummaries(ThinLTO.ModuleMap.size());
   ThinLTO.CombinedIndex.collectDefinedGVSummariesPerModule(
       ModuleToDefinedGVSummaries);