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From: "Fāng-ruì Sòng" <maskray@google.com>
To: Nicholas Guriev <nicholas@guriev.su>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH] elf: Rewrite long RESOLVE_MAP macro to a debug friendly function
Date: Tue, 3 May 2022 13:12:24 -0700	[thread overview]
Message-ID: <CAFP8O3JLS70yTZG81pTW9GjLOPeuqaD_=aAi62EuO_LFmSsbew@mail.gmail.com> (raw)
In-Reply-To: <b0502b5247fc5b17d988a6ca342d0852c5787f59.camel@guriev.su>

On 2022-05-03, Nicholas Guriev wrote:
>On Пн, 2022-05-02 at 14:20 -0700, Fangrui Song wrote:
>> I think this is useful. Does the size of dl-reloc.os code increase or
>> decrease with the change?
>>
>
>It's an interesting thing but the file has decreased by 7472 bytes with
>-Og and by 6896 bytes with -O3 optimization level (debug info enabled).
>Despite that readelf(1) sees a new local symbol, _dl_resolve_map.
>
>When debug info is disabled with the -g0 flag, size of the file is also
>reduced by 3296 and 1440 bytes respectively.

This is because in the default build mode (gcc -O2 -fPIC), gcc decides
to not inline _dl_resolve_map. That said, I run LD_DEBUG=statistics on
a large PIE (500+MiB) and do not see meaningful cycle difference.

The function has internal linkage (static) and it seems that the
prevailing style doesn't use `_dl_` prefix for such functions.

Otherwise the patch looks good to me.

  reply	other threads:[~2022-05-03 20:12 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-02 14:51 Nicholas Guriev
2022-05-02 21:20 ` Fangrui Song
2022-05-03 10:04   ` Nicholas Guriev
2022-05-03 20:12     ` Fāng-ruì Sòng [this message]
2022-05-07 13:33       ` [PATCH v3] " Nicholas Guriev
2022-05-09 13:38         ` Siddhesh Poyarekar
2022-05-14 14:27           ` Nicholas Guriev
2022-05-14 22:48             ` Fangrui Song
2022-05-15  0:58               ` Siddhesh Poyarekar
2022-05-22 22:24                 ` Fangrui Song
2022-05-23  7:28                   ` Siddhesh Poyarekar
2022-05-23 12:35                   ` Adhemerval Zanella
2022-05-23 13:02                     ` Siddhesh Poyarekar
2022-05-23 16:22                       ` Adhemerval Zanella
2022-05-23 16:33                         ` Siddhesh Poyarekar
2022-05-23 16:56                           ` Adhemerval Zanella
2022-05-03 19:14   ` [PATCH v2] " Nicholas Guriev

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