Re: Wrong sstate signatures for cross toolchain Was: [yocto] Building gdb-7.10 for arm with master

["Peter A. Bigot" <pab@pabigot.com>]

On 03/09/2016 05:02 PM, Richard Purdie wrote:
> On Wed, 2016-03-09 at 23:50 +0100, Martin Jansa wrote:
>> What's even more interesting is that even gcc-cross-initial has
>> different signatures for 2 ARM MACHINEs with different DEFAULTTUNES
>>
>> OE qemuarm7@ ~/build/oe-core $ grep ^DEFAULTTUNE= env.gdb-cross-arm*
>> env.gdb-cross-arm:DEFAULTTUNE="armv5te"
>> env.gdb-cross-arm7:DEFAULTTUNE="armv7a-neon"
>>
>> OE qemuarm7@ ~/build/oe-core $ ls tmp-glibc/sstate
>> -diff/1457556601/*/*/*gcc-cross-initial*/*do_configure*
>> tmp-glibc/sstate-diff/1457556601/qemuarm/x86_64-linux/gcc-cross
>> -initial-arm/5.3.0
>> -r0.do_configure.sigdata.e54e7a04acf1029cc37463114c7e4dba
>> tmp-glibc/sstate-diff/1457556601/qemuarm7/x86_64-linux/gcc-cross
>> -initial-arm/5.3.0
>> -r0.do_configure.sigdata.3496e3dde08a49b14462741cc6f8d239
>> OE qemuarm7@ ~/build/oe-core $ bitbake-diffsigs tmp-glibc/sstate
>> -diff/1457556601/*/*/*gcc-cross-initial*/*do_configure*
>> basehash changed from 5848199c69eee0db746de21c5458c13d to
>> 673cd8d19bc4cbea132900a670593df6
>> Variable EXTRA_OECONF value changed from '--with-newlib --without
>> -headers --disable-shared --disable-threads --disable-multilib -
>> -disable-__cxa_atexit --enable-languages=c --program
>> -prefix=${TARGET_PREFIX} --with-sysroot=/not/exist --with-build
>> -sysroot=${GCCCROSS_BUILDSYSROOT} ${EXTRA_OECONF_INITIAL}
>> ${@bb.utils.contains('DISTRO_FEATURES', 'ld-is-gold', '--with
>> -ld=${STAGING_BINDIR_TOOLCHAIN}/${TARGET_PREFIX}ld.bfd', '', d)}
>> ${EXTRA_OECONF_GCC_FLOAT} ${@get_gcc_ppc_plt_settings(bb, d)} --with
>> -native-system-header-dir=${SYSTEMHEADERS}${DISABLE_STATIC}
>> ${@gettext_oeconf(d)}
>> DISTRO_FEATURES{ld-is-gold} = Unset' to '--with-newlib --without
>> -headers --disable-shared --disable-threads --disable-multilib -
>> -disable-__cxa_atexit --enable-languages=c --program
>> -prefix=${TARGET_PREFIX} --with-sysroot=/not/exist --with-build
>> -sysroot=${GCCCROSS_BUILDSYSROOT} ${EXTRA_OECONF_INITIAL}
>> ${@bb.utils.contains('DISTRO_FEATURES', 'ld-is-gold', '--with
>> -ld=${STAGING_BINDIR_TOOLCHAIN}/${TARGET_PREFIX}ld.bfd', '', d)}
>> ${EXTRA_OECONF_GCC_FLOAT} ${@get_gcc_ppc_plt_settings(bb, d)} --with
>> -native-system-header-dir=${SYSTEMHEADERS}${DISABLE_STATIC}
>> ${@gettext_oeconf(d)} --with-arch=armv7-a
>> DISTRO_FEATURES{ld-is-gold} = Unset'
> To answer my own question, it looks like:
>
> gcc-configure-common.inc:EXTRA_OECONF_append_armv6 = " --with-arch=armv6"
> gcc-configure-common.inc:EXTRA_OECONF_append_armv7a = " --with-arch=armv7-a"
> gcc-configure-common.inc:EXTRA_OECONF_append_armv7ve = " --with-arch=armv7-a"
>
> which effectively comes from:
>
> http://git.yoctoproject.org/cgit.cgi/poky/commit/meta/recipes-devtools/gcc/gcc-configure-common.inc?id=c0a071e16ec04f485f06eece5b807e5afbe1c1f1
>
> The concept of having one gcc for each arch precludes such changes :(.

Yes.  Fundamentally the Yocto concept of arch appears to be inconsistent 
with gcc's concept in that the defaults for Yocto don't match the 
defaults for gcc on the same platform.  At the time I submitted that 
patch reworking how the toolchain is built wasn't feasible.

I'm not working with Yocto at this time so can't contribute to the 
solution, however if/when I get the opportunity I can help verify that 
the bug the patch fixed hasn't been re-introduced.

Peter
> I believe these overrides need to move to the gcc-target.inc file.
>
> Cheers,
>
> Richard
>