Re: [gentoo-dev] multilib and different CFLAGS for 32 and 64bit ABIs

[Anthony G. Basile]

On 03/29/15 15:07, Matt Turner wrote:
> On Sun, Mar 29, 2015 at 11:58 AM, Matthias Schwarzott <zzam@g.o> wrote:
>> Hi there!
>>
>> I updated my ~amd64 system recently to new hardware (Intel Core i3-4160).
>> Since then valgrind did no longer work for 32bit programs because
>> "-march=native" did choose instructions that valgrind does not support
>> in 32bit mode (even ld.so was unusable).
>>
>> After some research I put this into make.conf and now it works:
>> CFLAGS_x86="${CFLAGS_x86} -mno-avx2 -mno-sse4 -mno-bmi -mno-bmi2"
>> CXXFLAGS_x86="${CXXFLAGS_x86} -mno-avx2 -mno-sse4 -mno-bmi -mno-bmi2"
>>
>> Is this the best solution to the problem?
>> If yes, the valgrind ebuild could suggest something like this.
>> Either always show it or check cpu-flags first (is this maintainable?).
> Valgrind's policy is that they don't implement new instruction sets in 32-bit.
>
> Doing what you've done is the only option I'm aware of, short of
> implementing support in valgrind for these instructions.
>

This is a known issue.  I could add a pkg_postinst() message, but with 
valgrind, there would be lots of caveats.  Maybe open a bug and we'll 
track the issue in gentoo that way, like the strlen issue and a few 
other valgrind oldies.

-- 
Anthony G. Basile, Ph.D.
Gentoo Linux Developer [Hardened]
E-Mail    : blueness@g.o
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