https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66849
Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |ramana at gcc dot gnu.org
Resolution|--- |INVALID
--- Comment #2 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
(In reply to simon from comment #0)
> Having configured with
>
> --target=arm-eabi
> --with-arch=armv7
> --with-mode=thumb
If you are interested in armv7-m, please use --with-arch=armv7-m firstly.
>
> (I added --with-mode=thumb after failures building newlib)
>
> arm-eabi-gcc -dumpspecs says
>
> *multilib:
> . !marm !mthumb !mfloat-abi=hard;arm marm !mthumb !mfloat-abi=hard;thumb
> !marm mthumb !mfloat-abi=hard;fpu !marm !mthumb mfloat-abi=hard;arm/fpu marm
> !mthumb mfloat-abi=hard;
>
> or
>
> *multilib:
> . !marm !mthumb !mfloat-abi=hard;
> arm marm !mthumb !mfloat-abi=hard;
> thumb !marm mthumb !mfloat-abi=hard;
> fpu !marm !mthumb mfloat-abi=hard;
> arm/fpu marm !mthumb mfloat-abi=hard;
>
> which says to use the fpu subdirectory only if the link is done with
> neither -marm nor -mthumb; but the case of -mthumb -mfloat-abi=hard
> isn't covered, so that the main directory is searched instead of the
> fpu subdirectory; and for this set of options libgcc.a was built for
> softfp,
>
> File: /opt/gcc-5.1.0/lib/gcc/arm-eabi/5.1.0/libgcc.a(emutls.o)
> Attribute Section: aeabi
> File Attributes
> Tag_CPU_name: "7"
> Tag_CPU_arch: v7
> Tag_THUMB_ISA_use: Thumb-2
> Tag_ABI_PCS_wchar_t: 4
> Tag_ABI_FP_denormal: Needed
> Tag_ABI_FP_exceptions: Needed
> Tag_ABI_FP_number_model: IEEE 754
> Tag_ABI_align_needed: 8-byte
> Tag_ABI_align_preserved: 8-byte, except leaf SP
> Tag_ABI_enum_size: small
> Tag_ABI_optimization_goals: Aggressive Speed
> Tag_CPU_unaligned_access: v6
>
> as against the fpu version,
>
> File: /opt/gcc-5.1.0/lib/gcc/arm-eabi/5.1.0/fpu/libgcc.a(emutls.o)
> Attribute Section: aeabi
> File Attributes
> Tag_CPU_name: "7"
> Tag_CPU_arch: v7
> Tag_THUMB_ISA_use: Thumb-2
> Tag_FP_arch: VFPv2
> Tag_ABI_PCS_wchar_t: 4
> Tag_ABI_FP_denormal: Needed
> Tag_ABI_FP_exceptions: Needed
> Tag_ABI_FP_number_model: IEEE 754
> Tag_ABI_align_needed: 8-byte
> Tag_ABI_align_preserved: 8-byte, except leaf SP
> Tag_ABI_enum_size: small
> Tag_ABI_VFP_args: VFP registers <<<<<<<<<<<
> Tag_ABI_optimization_goals: Aggressive Speed
> Tag_CPU_unaligned_access: v6
>
> I made an overriding specs file,
>
> *multilib:
> . !marm !mthumb !mfloat-abi=hard;
> arm marm !mthumb !mfloat-abi=hard;
> thumb !marm mthumb !mfloat-abi=hard;
> fpu !marm mthumb mfloat-abi=hard;
> fpu !marm !mthumb mfloat-abi=hard;
> arm/fpu marm !mthumb mfloat-abi=hard;
>
> which appears to have done the trick.
Next if you want separate multilibs for float-abi=hard you may want to look at
some of the commented bits in t-arm to see how to do this or indeed into how
--with-multilib-list=aprofile works.
Alternatively I do think there's something with the M profile libs that can be
used today but with some obvious munging to make this work on trunk.
https://gcc.gnu.org/ml/gcc-patches/2013-07/msg01072.html
Thanks,
Ramana
