mesa: Resurrect SPARC asm code.

This rewrites the sparc GLAPI code so that it's PIC friendly and works
with all of the TLS/PTHREADS/64-bit/32-bit combinations properly.

As a result we can turn SPARC asm back on.  Currently it's only
enabled on Linux, as that's the only place where I can test this
stuff out.

For the moment the cliptest SPARC asm routines are disabled as they
are non-working.  The problem is that they use register %g7 as a
temporary which is where the threading libraries store the thread
pointer on SPARC.  I will fix that code up in a future change as it's
a pretty important routine to optimize.

Like x86 we do the runtime patch as a pthread once-invoked initializer
in init_glapi_relocs().

Unlike x86, however, our GLAPI stubs on SPARC are just two instruction
sequences that branch to a trampoline and put the GLAPI offset into a
register.  The trampoline is what we run-time patch.  The stubs thus
all look like:

glFoo:
	ba		__glapi_sparc_foo_stub
	 sethi		GLAPI_OFFSET(glFOO) * PTR_SIZE, %g3

This actually makes generate_entrypoint() a lot simpler on SPARC.  For
this case in generate_entrypoint() we generate stubs using a 'call'
instead of the 'ba' above to make sure it can reach.

In order to get a proper tail call going here, in the unpatched case,
we do several tricks.  To get the current PC, for example, we save the
return address register into a temporary, do a call, save the return
address register written by the call to another temporary, then
restore the original return address register value.  This is to
avoid having to allocate a stack frame.

This is necessary for PIC address formation.

This new GLAPI scheme lets us get rid of the ugly SPARC GLAPI hacks in
__glXInitialize() and one_time_init().

Signed-off-by: David S. Miller <[email protected]>

1 files changed, 0 insertions, 3 deletions

diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index a94bbf3fdf5..fb43054cddd 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -390,9 +390,6 @@ one_time_init( GLcontext *ctx )
          _mesa_ubyte_to_float_color_tab[i] = (float) i / 255.0F;
       }
 
-#ifdef USE_SPARC_ASM
-      _mesa_init_sparc_glapi_relocs();
-#endif
       if (_mesa_getenv("MESA_DEBUG")) {
          _glapi_noop_enable_warnings(GL_TRUE);
          _glapi_set_warning_func( (_glapi_warning_func) _mesa_warning );