Re: Preliminary 'wip-armhf' branch pushed

[Mark H Weaver <mhw@netris.org>]

John Darrington <john@darrington.wattle.id.au> writes:

> On Thu, Jan 01, 2015 at 02:11:19AM -0500, Mark H Weaver wrote:
>      John Darrington <john@darrington.wattle.id.au> writes:
>      
>      >      * You patched gcc/config/arm/linux-eabi.h unnecessarily.
>      >
>      > Without that patch, GCC actually builds soft-float code, even though
>      > you may have passed the --with-float=hard flag.  What bits of that
>      > patch do you think are not necessary?
>      
>      All of it seems to be unnecessary, by experiment.  I've used the
>      resulting GCC to compile the following test program:
>      
>      'foo' accepts the double arguments via registers and passes a double to
>      sinh via registers.  I also checked a variant that simply returned a*b,
>      and it was clearly returning the result via register as well.
>      
>      I think it's quite clear that this is using the hard-float ABI, no?
>
> My results showed that simple binaries like that compiled (and ran)
> ok.  The problems arose when linking with bigger projects.  I don't
> recall the details.  Have you tried building libc?

Yes, of course.  I looked further into this, and discovered that the
reason it all works is that the main 'gcc' driver arranges to pass
"-mfloat-abi=hard" (and several others) to 'cc1' and 'as'.

      Mark