Re: libffi mips code imported from GCC's svn

[David Daney <ddaney at avtrex dot com>]

Andrew Haley wrote:
> David Daney wrote:
> > Anthony et al.,
> >
> > Congratulations on 10 years of libffi.
> >
> > FYI:
> > Some of the changes I have committed to libffi MIPS support in GCC's 
> > svn depend on GCC extensions.  It probably will not work with anything 
> > less than GCC-4.3.
> >
> > Of concern are:
> >
> > src/mips/ffi.c:618 where I use the new gcc built-in 
> > __builtin___clear_cache() which is only available in GCC 4.3 and later.
> >
> > src/mips/ffitarget.h:136 where the GCC's __attribute__ extension is used.
>
> There was an older version of __builtin___clear_cache() that worked, wasn't
> there?   Presumably whatever __builtin___clear_cache() expands to, but
> perhaps
> that's subtarget dependent?

The short answer is no.  I am pretty sure that the current mips ffi 
closure code will only work with GCC 4.3.  I changed the way we are 
clearing the I-cache.  The new way only works in GCC 4.3.

It would be straight forward to make the cache clearing dependent on the 
compiler version, but that is not how it is implemented currently.

David Daney