From: Brian Dessent <brian@dessent.net>
To: gcc-help@gcc.gnu.org
Subject: Re: Symbols which were not used, still in binary
Date: Wed, 28 Jun 2006 21:20:00 -0000 [thread overview]
Message-ID: <44A2F293.7353A1FF@dessent.net> (raw)
In-Reply-To: <44A2E3C9.90201@eagercon.com>
Michael Eager wrote:
> Arguably, the linker should know
> that add is not referenced and could remove it, but linkers are not
> usually able to slice and dice object files.
You address this limitation by compiling with "-ffunction-sections
-fdata-sections -Wl,--gc-sections". However, it's still better to use
"static" on these kinds of local functions that are only used from the
same .o file. This has a number of benefits:
- it ensures that internal functions of a library are not exported for
use by other code when they are not part of the defined ABI/API
- it prevents them from taking up needless relocations, which can slow
linking
- when compiled -fpic (as in a shared library) it allows for direct
calls to the function instead of having to go through the PLT which is
slower
- it allows the compiler freedom to inline
Brian
next prev parent reply other threads:[~2006-06-28 21:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-28 19:58 Steve Kreyer
2006-06-28 20:17 ` Brian Dessent
2006-06-28 21:21 ` Steve Kreyer
2006-06-28 20:17 ` Michael Eager
2006-06-28 21:20 ` Brian Dessent [this message]
2006-06-29 5:16 ` Ingo Krabbe
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