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Re: [SPARC v8] Make ffi compatible with Solaris Studio aggregate return ABI


Ginn Chen <ginn.chen@oracle.com> writes:

> SPARC V8 Manual has:
> "When a procedure expecting an aggregate return value from a called function is
> compiled, an UNIMP instruction is placed after the delay-slot instruction
> following the CALL to the function in question. The immediate field in this
> UNIMP instruction contains the low-order twelve bits of the size (in bytes) of
> the area allocated by the caller for the aggregate value expected to be
> returned."
>
> The function compiled by gcc doesn't check the UNIMP instruction, it simply copy the returning struct and jump to %i7+12.
> The same function compiled by Solaris Studio, checks the struct size in UNIMP instruction, if it matches the returning struct it will copy the value and jump to %i7+12,
> if not it will do nothing and jump to %i7+8.
>
> So simply adding a nop in v8.S doesn't work with libraries compiled by Solaris Studio.
> e.g. if I compile testsuite/cls_8byte.c with Solaris Studio, it will not pass the test.
>
> I have a patch to alloc some executable space and make the call with exact struct size there.
> The patch is at:
> https://bugzilla.mozilla.org/show_bug.cgi?id=583206
>
> I have tested it on Solaris with both gcc and Solaris Studio.
>
> Please review it.

Thanks Ginn.  This looks good to me.  I've committed it to libffi.

AG


>
> Thanks,
>
> Ginn  


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