Fix autoupgrade logic for Objective-C class properties module flag

Previous we were issuing an error when linking a module containing
the new Objective-C metadata structure for class properties with an
"old" one.
Now instead we downgrade the module flag so that the Objective-C
runtime does not expect the new metadata structure.

This is consistent with what ld64 is doing on binary files.

Differential Revision: https://reviews.llvm.org/D24620

llvm-svn: 281685

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index a68247be973..8a5170fb631 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -1587,11 +1587,11 @@ bool llvm::UpgradeModuleFlags(Module &M) {
   }
   // "Objective-C Class Properties" is recently added for Objective-C. We
   // upgrade ObjC bitcodes to contain a "Objective-C Class Properties" module
-  // flag of value 0, so we can correclty report error when trying to link
-  // an ObjC bitcode without this module flag with an ObjC bitcode with this
-  // module flag.
+  // flag of value 0, so we can correclty downgrade this flag when trying to
+  // link an ObjC bitcode without this module flag with an ObjC bitcode with
+  // this module flag.
   if (HasObjCFlag && !HasClassProperties) {
-    M.addModuleFlag(llvm::Module::Error, "Objective-C Class Properties",
+    M.addModuleFlag(llvm::Module::Override, "Objective-C Class Properties",
                     (uint32_t)0);
     return true;
   }