gcc.misc-tests/outputs.exp: Use link test to check for -gsplit-dwarf support

We have noticed that, when running the GCC testsuite on AArch64
RTEMS 6, we have about 150 tests failing due to a link failure.
When investigating, we found that all the tests were failing
due to the use of -gsplit-dwarf.

On this platform, using -gsplit-dwarf currently causes an error
during the link:

    | /[...]/ld: a.out section `.unexpected_sections' will not fit
    |    in region `UNEXPECTED_SECTIONS'
    | /[...]/ld: region `UNEXPECTED_SECTIONS' overflowed by 56 bytes

The error is a bit cryptic, but the source of the issue is that
the linker does not currently support the sections generated
by -gsplit-dwarf (.debug_gnu_pubnames, .debug_gnu_pubtypes).
This means that the -gsplit-dwarf feature itself really isn't
supported on this platform, at least for the moment.

This commit enhances the -gsplit-dwarf support check to be
a compile-and-link check, rather than just a compile check.
This allows it to properly detect that this feature isn't
supported on platforms such as AArch64 RTEMS where the compilation
works, but not the link.

Tested on aarch64-rtems, where a little over 150 tests are now
passing, instead of failing, as well as on x86_64-linux, where
the results are identical, and where the .log file was also manually
inspected to make sure that the use of the -gsplit-dwarf option
was preserved.

gcc/testsuite/ChangeLog:

	* gcc.misc-tests/outputs.exp: Make the -gsplit-dwarf test
	a compile-and-link test rather than a compile-only test.

diff --git a/gcc/testsuite/gcc.misc-tests/outputs.exp b/gcc/testsuite/gcc.misc-tests/outputs.exp
index bc1fbe4..afae735 100644 (file)
--- a/gcc/testsuite/gcc.misc-tests/outputs.exp
+++ b/gcc/testsuite/gcc.misc-tests/outputs.exp
@@ -36,8 +36,8 @@ gcc_parallel_test_enable 0
 # having to deal with .dSYM directories, as long as -gsplit-dwarf is
 # not supported on platforms that use .dSYM directories.
 set gsplit_dwarf "-g -gsplit-dwarf"
-if ![check_no_compiler_messages gsplitdwarf object {
-    void foo (void) { }
+if ![check_no_compiler_messages gsplitdwarf executable {
+    int main (void) { return 0; }
 } "$gsplit_dwarf"] {
     set gsplit_dwarf ""
 }