Re: [PATCH v2 0/4] Add support for compiling with-ffunction-sections -fdata-sections

From: AmÃrico Wang
Date: Tue Apr 21 2009 - 10:02:32 EST


On Sun, Apr 05, 2009 at 07:14:34PM -0400, Tim Abbott wrote:
>Hi Linus,
>
>Here is a new version of the -ffunction-sections -fdata-sections patch
>series based on your current master. Please apply.
>
>When I sent a version of this patch series at the start of the merge
>window, Stephen Rothwell pointed out that the first patch conflicted
>with several changes in linux-next, and it should be resent near the
>end of the merge window once those changes were merged. There are
>now no conflicting changes staged in linux-next[0], so now is probably
>the optimal time to merge this patch series.
>
>[0] There is one trivial merge conflict with next-20090403 because
>e5083a63b6a8546c5fe1e571fe529e3939787ec2 was merged into master since
>then, but this will presumably disappear when next catches up tomorrow.
>
> -Tim Abbott
>
>--
>
>The purpose of this patch series is to make it possible to build the
>kernel with "gcc -ffunction-sections -fdata-sections". There are two
>major applications for this functionality: decreasing vmlinux image
>size with --gc-sections, and Ksplice.

Hello, Tim!

Nice work! But, don't -ffunction-sections and -fdata-sections have
collisions with '-g' and 'gprof'? Just like what gcc(1) describes.

CONFIG_DEBUG_INFO relies on '-g', and IIRIC, another project of
linux kernel is trying to 'gprof' the kernel too.

So, CONFIG_FUNCTION_DATA_SECTIONS probably needs to depend on
!CONFIG_DEBUG_INFO etc.

Am I missing something?

Thanks.

--
Live like a child, think like the god.

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