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Re: arm-elf MULTILIBS_DEFAULT
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Ralf Corsepius <corsepiu at faw dot uni-ulm dot de>
- Cc: GCC List <gcc at gcc dot gnu dot org>, Richard dot Earnshaw at arm dot com
- Date: Thu, 27 Feb 2003 10:36:12 +0000
- Subject: Re: arm-elf MULTILIBS_DEFAULT
- Organization: ARM Ltd.
- Reply-to: Richard dot Earnshaw at arm dot com
> Hi,
>
> I am trying to extend the multilib being used for arm-rtems (more less
> is identical to arm-*-elf).
>
> To do so, I introduced a gcc/config/arm/t-rtems containing this:
> MULTILIB_OPTIONS = marm/mthumb msoft-float/mhard-float
> MULTILIB_DIRNAMES = arm thumb soft fpu
> MULTILIB_EXCEPTIONS =
> MULTILIB_MATCHES =
>
> Resulting into this multilibs:
> # /opt/rtems/bin/arm-rtems-gcc -print-multi-lib
> .;
> thumb;@mthumb
> fpu;@mhard-float
> thumb/fpu;@mthumb at mhard-float
>
> [Note this assumes '.' to imply -msoft-float -marm]
>
> However, when trying to link an arbitrary fp-application using
> -msoft-float I end up with the linker complaining about FP-stuff:
>
> # /opt/rtems/bin/arm-rtems-gcc -msoft-float tmp.c
> /opt/rtems/lib/gcc-lib/arm-rtems/3.2.2/../../../../arm-rtems/bin/ld:
> ERROR: /opt/rtems/lib/gcc-lib/arm-rtems/3.2.2/libgcc.a(_df_to_sf.o) uses
> hardware FP, whereas a.out uses software FP
> ..
>
> If I understand correctly, this indicates that the arm-elf default flags
> do not match with arm-elf's MULTILIB_DEFAULTS (from arm-elf.h).
>
> What am I missing?
>
>
You need to ensure that the compiler driver passes the correct flags to
the assembler when the default multilib variant is selected. You do this
in rtems-elf.h (take a look at the way netbsd-elf.h does it).
R.