From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Brodkin Date: Wed, 31 Jan 2018 10:33:09 +0000 Subject: [Buildroot] [PATCH v2] gcc: Build libgcc with BR2_TARGET_OPTIMIZATION flags In-Reply-To: <20180118165639.2154-1-abrodkin@synopsys.com> References: <20180118165639.2154-1-abrodkin@synopsys.com> Message-ID: <1517394789.17823.36.camel@synopsys.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Hello, On Thu, 2018-01-18 at 19:56 +0300, Alexey Brodkin wrote: > libgcc gets built very early and what's more it is built not by > "normal" cross gcc later found in "output/host/usr/bin" but by > gcc's own bare-minimal version: output/build/host-gcc-xxx/build/./gcc/xgcc. > > Which in the end means BR2_TARGET_OPTIMIZATION is not applied to > cross-compiler via toolchain wrapper. > > But given libgcc is an essential target executable we may want it to > be built with the same "optimization" flags as all other libs and binaries. > > Technically this is doable with TARGET_ABI which is added to TARGET_CFLAGS > but user cannot [or at least is not supposed to] modify TARGET_ABI as it > is used for tunign for a particular platform. > > But still there might be a need to compile everything for tha target with > a special compiler option and this change allows for that. > > For eaxmple ARC still doesn't have properly working link-time relaxation > which requires us to compile everything properly from the beginning, otherwise > we may face a situation when huge apps/libs like Qt5WebKit might fail to pass > the final linkage because some symbols might be too far from each other as > by default gcc will try to use shorter relocations. Solution is as simple as > rebuild of everything with "-mlong-calls" so that all the symbols are > compiled with full 32-bit relocations. And now only libgcc causes problems > because it contains quite a few symbols used widely by other binaries like > millicode, some math stuff etc. > > Signed-off-by: Alexey Brodkin > Cc: Thomas Petazzoni > --- > > Changes v1 -> v2: > * Strip quotes from BR2_TARGET_OPTIMIZATION > Didn't notice a problem with 1 option in BR2_TARGET_OPTIMIZATION > but if another one is added libgcc configuration fails because: > CFLAGS_FOR_TARGET="-xxx "-yyy -zzz"" and thus > /bin/sh: -zzz: command not found Any comments on this one? If not please consider applying. -Alexey