[PATCH] MIPS: If a test in the MIPS testsuite requires standard library support check the sysroot supports the required test options.

[Matthew Fortune]

Moore, Catherine <Catherine_Moore@mentor.com> writes:
> > The recent changes to the MIPS GCC Linux sysroot
> > (https://gcc.gnu.org/ml/gcc-patches/2015-06/msg01014.html) have meant
> > that the include directory is now not global and is provided only for
> > each multi-lib configuration.  This means that for any test in the
> > MIPS GCC Testsuite that requires standard library support we need to
> > check if there is a multi-lib support for the test options, otherwise
> it might fail to compile.
> >
> > This patch adds this support to the testsuite and mips.exp files.
> > Firstly any test that requires standard library support has the
> > implicit option "(REQUIRES_STDLIB)" added to its dg-options.  Secondly
> > in mips.exp a pre- processor check is performed to ensure that when
> > expanding a testcase containing a "#include <stdlib.h>" using the
> > current set of test options we do not get file not found errors.  If
> > this happens we mark the testcase as unsupported.
> >
> > The patch has been tested on the mti/img elf/linux-gnu toolchains, and
> > there have been no new regressions.
> >
> > The patch and ChangeLog are below.
> >
> > Ok to commit?
> >
> >
> Yes.  This looks good.

I had some comments on this that I hadn't got round to posting. The fix in
this patch is not general enough as the missing header problem comes in
two (related) forms:

1) Using the new MTI and IMG sysroot layout we can end up with GCC looking
   for headers in a sysroot that simply does not exist. The current patch
   handles this.
2) Using any sysroot layout (i.e. a simple mips-linux-gnu) it is possible
   for the stdlib.h header to be found but the ABI dependent gnu-stubs
   header may not be installed depending on soft/hard nan1985/nan2008.

The test for stdlib.h needs to therefore verify that preprocessing succeeds
rather than just testing for an error relating to stdlib.h. This could be
done by adding a further option to mips_preprocess to indicate the processor
output should go to a file and that the caller wants the messages emitted
by the compiler instead.

A second issue is that you have added (REQUIRES_STDLIB) to too many tests.
You only need to add it to tests that request a compiler option (via
dg-options) that could potentially lead to forcing soft/hard nan1985/nan2008
directly or indirectly. So -mips32r6 implies nan2008 so you need it -mips32r5
implies nan1985 so you need it. There are at least two tests which don't
need the option but you need to check them all so we don't run the check
needlessly.

Thanks,
Matthew