Re: Add -foffload-abi support for PPC

[Thomas Schwinge <thomas@codesourcery.com>]

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Hi!

On Thu, 8 Oct 2015 11:19:05 -0500, James Norris <jnorris@codesourcery.com> wrote:
> On 10/07/2015 08:51 AM, David Edelsohn wrote:
> > On Wed, Oct 7, 2015 at 4:02 AM, Thomas Schwinge <thomas@codesourcery.com> wrote:
> >
> >>  From a quick look at the *_TYPE_SIZE definitions in
> >> gcc/config/rs6000/rs6000.h as well as
> >> <http://refspecs.linuxfoundation.org/elf/elfspec_ppc.pdf>, "3-1
> >> Fundamental Types", and
> >> <http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#FUND-TYPE>,
> >> I gather we're dealing with regular ilp32/lp64 here.  Then, I assume the
> >> right thing is to use the 64BIT flag from gcc/config/rs6000/sysv4.opt
> >> (which, per gcc/config.gcc I suppose is used for the relevant
> >> powerpc64le-linux-gnu configuration).  (David?)
> >
> > TARGET_64BIT is the appropriate macro to test.
> >
> >>
> >> I'm not sure where to place the TARGET_OFFLOAD_OPTIONS #define and the
> >> function definition in rs6000.c.  (David?)
> >
> > As mentioned earlier, only PPC64LE is supported.
> >
> > I'm not sure if it really matters if this is defined in ELF-specific
> > portion of the file or a general place, although it never will be
> > called by other configurations.
> >
> > Thanks, David
> >
> 
> I've revised the patch from the review comments (thank you) and
> is attached.
> 
> Regtested on x86_64 and powerpcle64.
> 
> OK for trunk?

> --- a/gcc/config/rs6000/rs6000.c
> +++ b/gcc/config/rs6000/rs6000.c

> +/* Implement the TARGET_OFFLOAD_OPTIONS hook.  */
> +static char *
> +rs6000_offload_options (void)
> +{
> +  return xstrdup ("-foffload-abi=lp64");
> +}

Well, that's a stripped-down variant of what I had suggested:

    static char *
    rs6000_offload_options (void)
    {
      if (TARGET_64BIT)
        return xstrdup ("-foffload-abi=lp64");
      else
        return xstrdup ("-foffload-abi=ilp32");
    }

If you return -foffload-abi=lp64 unconditionally, strange things will
happen for -m32 compilation (ABI mismatch).


Grüße,
 Thomas

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