Re: [PATCH] Fix ms-sysv.exp testsuite FAILs (PR c/83117)

[Jakub Jelinek <jakub@redhat.com>]

On Mon, Nov 27, 2017 at 05:02:32PM -0600, Daniel Santos wrote:
> > --- gcc/testsuite/gcc.target/x86_64/abi/ms-sysv/gen.cc.jj	2017-05-22 10:49:45.000000000 +0200
> > +++ gcc/testsuite/gcc.target/x86_64/abi/ms-sysv/gen.cc	2017-11-27 11:57:14.889570915 +0100
> > @@ -392,7 +392,7 @@ static void make_do_tests_decl (const ve
> >  	    continue;
> >  
> >  	  comma.reset ();
> > -	  out << "static __attribute__ ((ms_abi)) long (*const do_test_"
> > +	  out << "static __attribute__ ((ms_abi)) long (*do_test_"
> >  	      << (unaligned ? "u" : "")
> >  	      << (varargs ? "v" : "") << i << ") (";
> 
> I don't have a problem with removing const, it's only there for
> const-correctness and caution.  I just posted to the PR a bit ago and
> I'm curious if there is a better approach when using assembly stubs that
> are meant to be called in varying ways.  CV would work also, although
> there's no real need to refetch the address before each use.
> 
> If you don't have a better way to do this then please use this patch.

I've verified the resulting *.optimized dump as well as assembly is
practically identical without/with the patch, only differences are in
SSA_NAME versions, in assembly the .LCNNNN and .LCFINNNN constants are
different but otherwise it is the same - the functions are emitted in
different orders by cgraph and committed the patch.

Using assembly stubs that are meant to be called in varying ways should
just be avoided in portable programs, you could e.g. in the generator
instead of all those:
extern __attribute__ ((ms_abi)) long do_test_aligned ();
extern __attribute__ ((ms_abi)) long do_test_unaligned ();
static __attribute__ ((ms_abi)) long (*do_test_1) (long a) = (void*)do_test_aligned;
static __attribute__ ((ms_abi)) long (*do_test_v1) (long a, ...) = (void*)do_test_aligned;
static __attribute__ ((ms_abi)) long (*do_test_u1) (long a) = (void*)do_test_unaligned;
static __attribute__ ((ms_abi)) long (*do_test_uv1) (long a, ...) = (void*)do_test_unaligned;
emit:
extern __attribute__ ((ms_abi)) long do_test_1 (long a);
asm (".text; do_test_1: jmp do_test_aligned; .previous");
extern __attribute__ ((ms_abi)) long do_test_v1 (long a, ...);
asm (".text; do_test_v1: jmp do_test_aligned; .previous");
extern __attribute__ ((ms_abi)) long do_test_1 (long a);
asm (".text; do_test_u1: jmp do_test_unaligned; .previous");
extern __attribute__ ((ms_abi)) long do_test_1 (long a, ...);
asm (".text; do_test_uv1: jmp do_test_unaligned; .previous");
or something similar.

	Jakub