[PATCH] D71219: Fix conflict value for metadata "Objective-C Garbage Collection" in the mix of swift and Objective-C bitcode

[Steven Wu via Phabricator via llvm-commits]

steven_wu added a comment.

> I agree with all of this except that I'm not sure there's any situation where ObjC and Swift translation units should be disagreeing about the ObjC-specific parts of the OBJC_IMAGE_INFO.

The lower bits of the flag is for objc info and here is the definition:
#define OBJC_IMAGE_SUPPORTS_GC						(1<<1)
#define OBJC_IMAGE_REQUIRES_GC						(1<<2)
#define OBJC_IMAGE_OPTIMIZED_BY_DYLD				(1<<3)
#define OBJC_IMAGE_SUPPORTS_COMPACTION				(1<<4)
#define OBJC_IMAGE_IS_SIMULATED						(1<<5)
#define OBJC_IMAGE_HAS_CATEGORY_CLASS_PROPERTIES	(1<<6)

The 0x40 bit is actually OBJC_IMAGE_HAS_CATEGORY_CLASS_PROPERTIES, which probably can differ from translation unit to translation unit even within ObjC. Some of the other bits should not be different. That is why I say you can break the bits down even more if needed.


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  https://reviews.llvm.org/D71219/new/

https://reviews.llvm.org/D71219