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Date: Tue, 16 Mar 2021 22:27:49 +0100
From: Mark Wielaard <mark@klomp.org>
To: Tom de Vries <tdevries@suse.de>
Cc: dwz@sourceware.org, jakub@redhat.com
Subject: Re: [PATCH] Add --devel-skip-producer
Message-ID: <20210316212749.GC3054@wildebeest.org>
References: <20210316141919.GA24635@delia>
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Hi Tom,

On Tue, Mar 16, 2021 at 03:19:20PM +0100, Tom de Vries wrote:
> In PR27588 a test-case was reported where dwz did not optimize due
> to illegal DWARF produced by nasm:
> ...
> $ dwz libxul.so -o libxul.so.z
> dwz: libxul.so: loclistptr attribute, yet no .debug_loc section
> ...
> 
> Add an option --devel-skip-producer <producer> such that we can filter out
> CUs coming from a particular producer, such that we have instead:
> ...
> $ readelf -wi libxul.so | grep DW_AT_producer \
>     | sed 's/.*: //' | sort | uniq -c
>     176 clang LLVM (rustc version 1.50.0)
>       2 GNU AS 2.36.1
>       2 GNU C11 11.0.1 20210315 (experimental) <SNIP>
>      16 NASM 2.15.05
>      76 yasm 1.3.0
> $ dwz libxul.so -o libxul.so.z --devel-skip-producer NASM
> $ readelf -wi libxul.so.z | grep DW_AT_producer \
>     | sed 's/.*: //' | sort | uniq -c
>     176 clang LLVM (rustc version 1.50.0)
>       2 GNU AS 2.36.1
>       2 GNU C11 11.0.1 20210315 (experimental) <SNIP>
>      76 yasm 1.3.0
> ...
> 
> Any comments?

So this skips and then removes the whole CU (because we set die_remove
on the cu_die)?

It is useful as --devel option, but I would be against it as non-devel
option.

Cheers,

Mark