arm32v7

[tianon]

Cross-posting from #36 (comment):

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77447

I suspect you did not use --with-float=hard

https://sources.debian.net/src/gcc-6/6.3.0-18/debian/rules2/#L491-L536 is another good link where Debian adds a bunch of extra compile flags to ARM builds, like specifying exactly which ARM we're compiling for, and the features of it, which should fix our current build failure there:

/tmp/tmp.zQHpdm2qVk/./gcc/xgcc -B/tmp/tmp.zQHpdm2qVk/./gcc/ -B/usr/local/arm-linux-gnueabihf/bin/ -B/usr/local/arm-linux-gnueabihf/lib/ -isystem /usr/local/arm-linux-gnueabihf/include -isystem /usr/local/arm-linux-gnueabihf/sys-include    -g -O2 -O2  -g -O2 -DIN_GCC    -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wno-format -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include   -fPIC -fno-inline -g -DIN_LIBGCC2 -fbuilding-libgcc -fno-stack-protector   -fPIC -fno-inline -I. -I. -I../.././gcc -I/usr/src/gcc/libgcc -I/usr/src/gcc/libgcc/. -I/usr/src/gcc/libgcc/../gcc -I/usr/src/gcc/libgcc/../include  -DHAVE_CC_TLS  -o _clear_cache_s.o -MT _clear_cache_s.o -MD -MP -MF _clear_cache_s.dep -DSHARED -DL_clear_cache -xassembler-with-cpp -c /usr/src/gcc/libgcc/config/arm/lib1funcs.S
/tmp/tmp.zQHpdm2qVk/./gcc/nm -pg _clear_cache_s.o | mawk 'NF == 3 && $2 !~ /^[UN]$/ && $3 !~ /.*_compat/ && $3 !~ /.*@.*/ { print "\t.hidden", $3 }' > _clear_cache.visT
mv -f _clear_cache.visT _clear_cache.vis
/tmp/tmp.zQHpdm2qVk/./gcc/xgcc -B/tmp/tmp.zQHpdm2qVk/./gcc/ -B/usr/local/arm-linux-gnueabihf/bin/ -B/usr/local/arm-linux-gnueabihf/lib/ -isystem /usr/local/arm-linux-gnueabihf/include -isystem /usr/local/arm-linux-gnueabihf/sys-include    -g -O2 -O2  -g -O2 -DIN_GCC    -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wno-format -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include   -fPIC -fno-inline -g -DIN_LIBGCC2 -fbuilding-libgcc -fno-stack-protector   -fPIC -fno-inline -I. -I. -I../.././gcc -I/usr/src/gcc/libgcc -I/usr/src/gcc/libgcc/. -I/usr/src/gcc/libgcc/../gcc -I/usr/src/gcc/libgcc/../include  -DHAVE_CC_TLS  -o _clear_cache.o -MT _clear_cache.o -MD -MP -MF _clear_cache.dep -DL_clear_cache -xassembler-with-cpp -c /usr/src/gcc/libgcc/config/arm/lib1funcs.S -include _clear_cache.vis
/tmp/tmp.zQHpdm2qVk/./gcc/xgcc -B/tmp/tmp.zQHpdm2qVk/./gcc/ -B/usr/local/arm-linux-gnueabihf/bin/ -B/usr/local/arm-linux-gnueabihf/lib/ -isystem /usr/local/arm-linux-gnueabihf/include -isystem /usr/local/arm-linux-gnueabihf/sys-include    -g -O2 -O2  -g -O2 -DIN_GCC    -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wno-format -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include   -fPIC -fno-inline -g -DIN_LIBGCC2 -fbuilding-libgcc -fno-stack-protector   -fPIC -fno-inline -I. -I. -I../.././gcc -I/usr/src/gcc/libgcc -I/usr/src/gcc/libgcc/. -I/usr/src/gcc/libgcc/../gcc -I/usr/src/gcc/libgcc/../include  -DHAVE_CC_TLS  -o _muldi3.o -MT _muldi3.o -MD -MP -MF _muldi3.dep -DL_muldi3 -c /usr/src/gcc/libgcc/libgcc2.c -fvisibility=hidden -DHIDE_EXPORTS
In file included from /usr/include/stdio.h:27:0,
                 from /usr/src/gcc/libgcc/../gcc/tsystem.h:87,
                 from /usr/src/gcc/libgcc/libgcc2.c:27:
/usr/include/features.h:364:12: fatal error: sys/cdefs.h: No such file or directory
 #  include <sys/cdefs.h>
            ^~~~~~~~~~~~~
compilation terminated.
make[3]: *** [_muldi3.o] Error 1
Makefile:491: recipe for target '_muldi3.o' failed
make[3]: Leaving directory '/tmp/tmp.zQHpdm2qVk/arm-linux-gnueabihf/libgcc'
make[2]: *** [all-stage1-target-libgcc] Error 2
Makefile:21935: recipe for target 'all-stage1-target-libgcc' failed
make[2]: Leaving directory '/tmp/tmp.zQHpdm2qVk'
make[1]: *** [stage1-bubble] Error 2
Makefile:27403: recipe for target 'stage1-bubble' failed
make[1]: Leaving directory '/tmp/tmp.zQHpdm2qVk'
make: *** [all] Error 2
Makefile:940: recipe for target 'all' failed
The command '/bin/sh -c set -ex 	&& buildDeps=' 		dpkg-dev 		flex 	' 	&& apt-get update 	&& apt-get install -y --no-install-recommends $buildDeps 	&& rm -r /var/lib/apt/lists/* 	&& curl -fSL "http://ftpmirror.gnu.org/gcc/gcc-$GCC_VERSION/gcc-$GCC_VERSION.tar.bz2" -o gcc.tar.bz2 	&& curl -fSL "http://ftpmirror.gnu.org/gcc/gcc-$GCC_VERSION/gcc-$GCC_VERSION.tar.bz2.sig" -o gcc.tar.bz2.sig 	&& gpg --batch --verify gcc.tar.bz2.sig gcc.tar.bz2 	&& mkdir -p /usr/src/gcc 	&& tar -xf gcc.tar.bz2 -C /usr/src/gcc --strip-components=1 	&& rm gcc.tar.bz2* 	&& cd /usr/src/gcc 	&& ./contrib/download_prerequisites 	&& { rm *.tar.* || true; } 	&& for f in config.guess config.sub; do 		wget -O "$f" "https://git.savannah.gnu.org/cgit/config.git/plain/$f?id=7d3d27baf8107b630586c962c057e22149653deb"; 		find -mindepth 2 -name "$f" -exec cp -v "$f" '{}' ';'; 	done 	&& dir="$(mktemp -d)" 	&& cd "$dir" 	&& gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)" 	&& /usr/src/gcc/configure 		--build="$gnuArch" 		--disable-multilib 		--enable-languages=c,c++,fortran,go 	&& make -j"$(nproc)" 	&& make install-strip 	&& cd .. 	&& rm -rf "$dir" 	&& apt-get purge -y --auto-remove $buildDeps' returned a non-zero code: 2

Embedding that Debian code in case the link changes (it's the version from stretch so may or may not change before release):

ifneq (,$(findstring arm, $(DEB_TARGET_GNU_CPU)))
  ifeq ($(multilib),yes)
    CONFARGS += --enable-multilib
  endif
  CONFARGS += --disable-sjlj-exceptions
  # FIXME: libjava is not ported for thumb, this hack only works for
  # separate gcj builds
  ifneq (,$(filter %armhf,$(DEB_TARGET_ARCH)))
    ifeq ($(distribution),Raspbian)
      with_arm_arch = armv6
      with_arm_fpu = vfp
    else
      ifneq (,$(findstring gcj,$(PKGSOURCE)))
        with_arm_arch = armv6
      else
        with_arm_arch = armv7-a
      endif
      with_arm_fpu = vfpv3-d16
    endif
  else
    # armel
    ifeq ($(derivative),Debian)
      with_arm_arch = armv4t
    else ifneq (,$(filter $(distrelease),karmic))
      with_arm_arch = armv6
      with_arm_fpu = vfpv3-d16
    else ifneq (,$(filter $(distrelease),lucid maverick natty oneiric precise))
      ifneq (,$(findstring gcj,$(PKGSOURCE)))
        with_arm_arch = armv6
      else
        with_arm_arch = armv7-a
      endif
      with_arm_fpu = vfpv3-d16
    else
      with_arm_arch = armv5t  # starting with quantal
    endif
  endif
  CONFARGS += --with-arch=$(with_arm_arch)
  ifneq (,$(with_arm_fpu))
    CONFARGS += --with-fpu=$(with_arm_fpu)
  endif
  CONFARGS += --with-float=$(float_abi)
  ifeq ($(with_arm_thumb),yes)
    CONFARGS += --with-mode=thumb
  endif
endif

[tianon]

With 3b33871, this seems to be slightly better. It built for a long time, given the speed of armhf, and eventually failed with the following:

No rule to make target '/usr/src/gcc/gcc/sync-builtinsndef', needed by 'tree-ssa-loop-prefetch.o

[tianon]

I tried this again on our newer ARM hardware and it completed successfully, and in a reasonable amount of time!