From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Fri, 14 Feb 2014 15:36:34 +0100 Subject: [Buildroot] [PATCH 1/1] Use libm.so when testing external compiler ABI In-Reply-To: <1392385415-19367-1-git-send-email-syntheticpp@gmx.net> References: <1392385415-19367-1-git-send-email-syntheticpp@gmx.net> Message-ID: <20140214153634.1377738a@skate> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Dear Peter K?mmel, On Fri, 14 Feb 2014 14:43:35 +0100, Peter K?mmel wrote: > crt1.o could not be used to test for eabihf because > it does not list the tag Tag_ABI_VFP_args. > > Signed-off-by: Peter K?mmel > --- > toolchain/helpers.mk | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/toolchain/helpers.mk b/toolchain/helpers.mk > index faa9d90..c41d757 100644 > --- a/toolchain/helpers.mk > +++ b/toolchain/helpers.mk > @@ -284,8 +284,8 @@ check_arm_abi = \ > echo "External toolchain uses the unsuported OABI" ; \ > exit 1 ; \ > fi ; \ > - EXT_TOOLCHAIN_CRT1=`LANG=C $${__CROSS_CC} -print-file-name=crt1.o` ; \ > - if $${__CROSS_READELF} -A $${EXT_TOOLCHAIN_CRT1} | grep -q "Tag_ABI_VFP_args:" ; then \ > + EXT_TOOLCHAIN_LIBM=`LANG=C $${__CROSS_CC} -print-file-name=libm.so` ; \ > + if $${__CROSS_READELF} -A $${EXT_TOOLCHAIN_LIBM} | grep -q "Tag_ABI_VFP_args:" ; then \ > EXT_TOOLCHAIN_ABI="eabihf" ; \ > else \ > EXT_TOOLCHAIN_ABI="eabi" ; \ This is more or less the same patch as proposed at https://bugs.busybox.net/show_bug.cgi?id=6842. Originally, the reason why I had chosen to check crt1.o instead of a .so file is because crt1.o exists even for purely static toolchains (i.e no support for shared libraries). Even though I admit that the likelihood of finding such toolchains for ARM is quite small, I'd like to understand why crt1.o doesn't have the Tag_ABI_VFP_args. Is this happening when using a Buildroot toolchain as an external toolchain? If so, maybe it's Buildroot who actually does something wrong when building the toolchain, because the Linaro toolchains do have Tag_ABI_VFP_args in crt1.o : The multilib variant compiled EABIhf: $ arm-linux-gnueabihf-readelf -A ./arm-linux-gnueabihf/libc/usr/lib/arm-linux-gnueabihf/crt1.o | grep Tag_ABI_VFP_args Tag_ABI_VFP_args: VFP registers $ The multilib variant compiled EABI: $ arm-linux-gnueabihf-readelf -A ./arm-linux-gnueabihf/libc/usr/lib/arm-linux-gnueabi/crt1.o | grep Tag_ABI_VFP_args $ So I'd prefer to have an understanding of why crt1.o is not EABIhf before applying this patch. Thanks! Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com