arm-elf float-abi defaults...

Richard Earnshaw
Sat May 15 09:08:00 GMT 2010

On Tue, 2010-05-11 at 17:40 -0400, DJ Delorie wrote:
> I discovered that if you build a plain arm-elf toolchain, the default
> float-abis for gcc and gas don't match.  I added this patch locally to
> make it "just work" but it seems to me it would be better to have the
> defaults match, although I'm not sure how to enforce that.  Comments?
> Suggestions?
> Index: gcc/config/arm/elf.h
> ===================================================================
> RCS file: gcc/config/arm/elf.h,v
> --- gcc/config/arm/elf.h
> +++ gcc/config/arm/elf.h
> @@ -41,7 +41,13 @@
>  #endif
> +  "%{!msoft-float:%{!mhard-float:%{!mfloat-abi=*:-mfloat-abi=soft}}}"
> +#else
> +  "%{!msoft-float:%{!mhard-float:%{!mfloat-abi=*:-mfloat-abi=hard}}}"
> +#endif
>  #endif

Sorry for the delay replying, I've been travelling.

The above is probably technically correct, but it has one major problem,
IIRC: it breaks backwards compatibility with existing objects that are
incorrectly labelled by default -- ie probably most of them, for most
users.  Also note that there is no way for a user to force the linker to
ignore this problem, so changing it would effectively force all old
object files to be re-compiled -- something that may well not be

Given that arm-elf is on the verge of being deprecated, I'm not
convinced this is a good idea.


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