1 files changed, 7 insertions, 2 deletions
diff --git a/lib/CodeGen/ObjectFilePCHContainerOperations.cpp b/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
index 754f9968b67f2..37ecc05aa1eee 100644
--- a/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
+++ b/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
@@ -171,7 +171,8 @@ public:
     // Prepare CGDebugInfo to emit debug info for a clang module.
     auto *DI = Builder->getModuleDebugInfo();
     StringRef ModuleName = llvm::sys::path::filename(MainFileName);
-    DI->setPCHDescriptor({ModuleName, "", OutputFileName, ~1ULL});
+    DI->setPCHDescriptor({ModuleName, "", OutputFileName,
+                          ASTFileSignature{{{~0U, ~0U, ~0U, ~0U, ~1U}}}});
     DI->setModuleMap(MMap);
   }
 
@@ -241,7 +242,11 @@ public:
 
     // PCH files don't have a signature field in the control block,
     // but LLVM detects DWO CUs by looking for a non-zero DWO id.
-    uint64_t Signature = Buffer->Signature ? Buffer->Signature : ~1ULL;
+    // We use the lower 64 bits for debug info.
+    uint64_t Signature =
+        Buffer->Signature
+            ? (uint64_t)Buffer->Signature[1] << 32 | Buffer->Signature[0]
+            : ~1ULL;
     Builder->getModuleDebugInfo()->setDwoId(Signature);
 
     // Finalize the Builder.