Fix conflict value for metadata "Objective-C Garbage Collection" in the mix of swift and Objective-C bitcode

Summary:
The change is to fix conflict value for metadata "Objective-C Garbage Collection" in the mix of swift and Objective-C bitcode.
The purpose is to provide the support of LTO for swift and Objective-C mixed project.

Reviewers: rjmccall, ahatanak, steven_wu

Reviewed By: rjmccall, steven_wu

Subscribers: manmanren, mehdi_amini, hiraditya, dexonsmith, llvm-commits, jinlin

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71219

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index d36d04e..2ce285c 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -84,6 +84,15 @@ static void GetObjCImageInfo(Module &M, unsigned &Version, unsigned &Flags,
     } else if (Key == "Objective-C Image Info Section") {
       Section = cast<MDString>(MFE.Val)->getString();
     }
+    // Backend generates L_OBJC_IMAGE_INFO from Swift ABI version + major + minor +
+    // "Objective-C Garbage Collection".
+    else if (Key == "Swift ABI Version") {
+      Flags |= (mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue()) << 8;
+    } else if (Key == "Swift Major Version") {
+      Flags |= (mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue()) << 24;
+    } else if (Key == "Swift Minor Version") {
+      Flags |= (mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue()) << 16;
+    }
   }
 }