Re: [PATCH][RFC] add --enable-zstd-compressed-debug-sections configure option

[Fangrui Song <maskray@google.com>]

On 2022-09-30, Martin Liška wrote:
>On 9/30/22 13:25, Pedro Alves wrote:
>> On 2022-09-30 10:48 a.m., Martin Liška wrote:
>>> Hello.
>>>
>>> The patch can set up default compression algorithm as zstd instead of the
>>> default zlib-gabi.
>>>
>>> The patch is lightly tested as readelf can't decompress debug sections:
>>> https://sourceware.org/bugzilla/show_bug.cgi?id=29640
>>>
>>> Thoughts?
>>>
>>> ChangeLog:
>>>
>>> 	* configure.ac: Add --enable-zstd-compressed-debug-sections
>>> 	configure option.
>>> 	* configure: Regenerate.
>>
>> This may become a bit awkward in the future when other better format appears, and you want to
>> switch to use it by default.  Like, imagine zstd2 is invented.  At that point we'd have to decide
>> whether to add code to error out if the user specifies both
>>    "--enable-zstd-compressed-debug-sections --enable-zstd2-compressed-debug-sections",
>> or always pick the latter option, or some such.
>
>Understood.
>
>>
>> IMHO, it seems cleaner and more future proof to add instead:
>>
>>   --enable-default-compressed-debug-sections=zlib|zlib-gnu|zlib-gabi|zstd
>>
>> WDYT?
>
>Yep, it's much nicer. Anyway, lemme try preparing a patch that does a bit of refactoring
>before I introduce such a patch.
>
>Martin

Personally I'll prefer that the compiler drivers (GCC and Clang) pass
the default options to ld/as, and they have good infrastructure for
customization...  (Clang recently got better configuration file
(https://clang.llvm.org/docs/UsersManual.html#configuration-files)
support which enables more convenient default driver options.)

Setting default options in ld/as allow very few projects which bypass
the compiler driver to use zstd compressed debug sections but the
benefit is probably low...