[PATCH] D80765: [lld] Handle bitcode comdat groups separately to deduplicate thinlto comdat sections

[Sam Clegg via Phabricator via llvm-commits]

sbc100 added a comment.

In D80765#2063931 <https://reviews.llvm.org/D80765#2063931>, @christylee wrote:

> @sbc100 What would be a good way to go about writing a test for this?  The reason why I noticed this bug was because .debug_types are not deduplicated in thinlto, but writing a lld test case using debug metadata seems clunky.




>      
> 
> I've also tried something like this but it doesn't repro:
> 
>   ; REQUIRES: x86
>   ; RUN: llvm-as %s -o %t.o
>   ; RUN: llc %t.o -o %t2.o -filetype=obj
>   ; RUN: ld.lld %t.o %t2.o %t.o %t2.o -o %t3.o --shared
>   ; RUN: llvm-readobj --symbols %t3.o | FileCheck %s
>   
>   ; CHECK:      Name: foo
>   ; CHECK-NEXT: Value:
>   ; CHECK-NEXT: Size: 1
>   ; CHECK-NEXT: Binding: Global
>   ; CHECK-NEXT: Type: Function
>   ; CHECK-NEXT: Other: 0
>   ; CHECK-NEXT: Section: .text
>   
>   target triple = "x86_64-unknown-linux-gnu"
>   target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
>   
>   $foo = comdat any
>   define void @foo() comdat {
>     ret void
>   }
>   

I'm sorry I've not looked into this in much detail but shouldn't this same bug reproduce with all comdats?       Maybe there is something different about debug metatdata?     BTW, the test above doesn't use lto or thinglto does it?


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