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

Mon Feb 24 16:27:43 PST 2020

jinlin added a comment.

In D71219#1791936 <https://reviews.llvm.org/D71219#1791936>, @steven_wu wrote:

> > 
> > 
> > 1. I will add a  llvm-link tests for combining objc and swift bitcode.
> > 2. What do you mean by "codegen tests for correct value in the object file"? There is no "object file" in the picture. Are you asking for a test that checks the value in the output of llvm-link?
>
> I think the decision was to break apart the current "Objective-C Garbage Collection" metadata. You need codegen test to test that OBJC_IMAGE_INFO is generated correctly after breaking apart the value.

I have question regarding this. Let's assume we have one assembly file from Objective-C and another one from Swift.

Objective-C assembly:
L_OBJC_IMAGE_INFO:
	.long	0
	.long	64

Swift assembly:

L_OBJC_IMAGE_INFO:
	.long	0
	.long	83953472

Let's assume that the llvm-link can link Swift bitcode and Objective-C bit successfully and the llc can generate the assembly for the merged output bitcode.

In the final assembly file, what value do you expect for L_OBJC_IMAGE_INFO?

> 
> 
>> 3. Let us keep the auto upgrade to a different future diff to keep each diff self contained. Is that ok?
> 
> I disagree with that. That is leaving a gap for incompatible bitcode.
> 
> Steven

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