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Re: [PATCH] ARM: Use different linker path for hardfloat ABI
- From: dann frazier <dann dot frazier at canonical dot com>
- To: Michael Hope <michael dot hope at linaro dot org>
- Cc: Richard Earnshaw <rearnsha at arm dot com>, "cross-distro at lists dot linaro dot org" <cross-distro at lists dot linaro dot org>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 3 Apr 2012 08:31:14 -0600
- Subject: Re: [PATCH] ARM: Use different linker path for hardfloat ABI
- References: <20120329193401.GA14860@dannf.org> <4F75F2E2.3030909@arm.com> <20120402210653.GC28152@dannf.org> <CANLjY-nk7ML5QMBd0bKRJBA9stUOdvu1tWZqmFHxpRzObzFw1Q@mail.gmail.com>
On Tue, Apr 03, 2012 at 03:29:06PM +1200, Michael Hope wrote:
> On 3 April 2012 09:06, dann frazier <dann.frazier@canonical.com> wrote:
> > On Fri, Mar 30, 2012 at 06:52:34PM +0100, Richard Earnshaw wrote:
> >> On 29/03/12 20:34, dann frazier wrote:
> >> > This is an updated version of a patch Debian and Ubuntu are using to
> >> > use an alternate linker path for hardfloat binaries. The difference
> >> > with this one is that it covers the case where no float flag
> >> > was passed in, defaulting to the softfloat path.
>
> Hi Dann. The change should be in the EABI specific linux-eabi.h
> instead of the shared/OABI linux-elf.h. It breaks support for uClibc
> and Bionic by always using the GLIBC loader in hard float mode. The
> final line in the spec is missing a '=hard' and always adds
> /lib/ld-linux.so.3.
>
> How about:
>
> 2012-04-03 Michael Hope <michael.hope@linaro.org>
>
> * config/arm/linux-eabi.h (GLIBC_DYNAMIC_LINKER_HARD_FLOAT): Define.
> (GLIBC_DYNAMIC_LINKER): Redefine to use the hard float loader.
Nice, thanks Michael. I'd looked at doing something similar, but I
wasn't sure that defining GLIBC_DYNAMIC_LINKER to a spec macro would
work :)
-dann
>
> diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
> index 80bd825..8498472 100644
> --- a/gcc/config/arm/linux-eabi.h
> +++ b/gcc/config/arm/linux-eabi.h
> @@ -62,7 +62,12 @@
> /* Use ld-linux.so.3 so that it will be possible to run "classic"
> GNU/Linux binaries on an EABI system. */
> #undef GLIBC_DYNAMIC_LINKER
> -#define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.3"
> +#define GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "/lib/ld-linux.so.3"
> +#define GLIBC_DYNAMIC_LINKER_HARD_FLOAT
> "/lib/arm-linux-gnueabihf/ld-linux.so.3"
> +#define GLIBC_DYNAMIC_LINKER \
> + "%{mhard-float:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \
> + %{mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \
> + %{!mfloat-abi=hard:%{!mhard-float:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "}}"
>
> /* At this point, bpabi.h will have clobbered LINK_SPEC. We want to
> use the GNU/Linux version, not the generic BPABI version. */
>
>
> which works for the following test cases:
> gcc -mhard-float foo.c => /lib/arm-linux-gnueabihf/ld-linux.so.3
> gcc -mfloat-abi=hard foo.c => /lib/arm-linux-gnueabihf/ld-linux.so.3
> gcc -msoft-float foo.c => /lib/ld-linux.so.3
> gcc -mfloat-abi=softfp foo.c => /lib/ld-linux.so.3
> gcc -mbionic => /system/bin/linker
> gcc -mbionic -mhard-float => /system/bin/linker
> gcc -muclibc => /lib/ld-uClibc.so.0
> gcc -muclibc -mhard-float => /lib/ld-uClibc.so.0
>
> -- Michael