OpenMP parallel region scope tests

OpenMP parallel region scope tests

Add tests which check for accessibility of variables from within
various OpenMP parallel regions.

Tested on Fedora 27, 28, 29, 30, and 31.  I also tested with my OpenMP
work on Fedora 30.  The test has been annotated with setup_xfail and
setup_kfail statements so that there are no unexpected failures on any
of these platforms when using gcc.  Better still, for my own testing
anyway, is that there are also no XPASSes or KPASSes either.  So,
regardless of platform, when using gcc, and regardless of whether my
(not yet public) OpenMP work is used, seeing a FAIL indicates a real
problem.

Fedora 27 results:

        # of expected passes            85
        # of expected failures          65

(Note: I have not retested F27 since v1 of the patch; it's possible
that the numbers will be slightly different for v2.)

Fedora 28, 29, 30 results:

        # of expected passes            131
        # of expected failures          4
        # of known failures             16

Fedora 30, 31 results w/ my OpenMP work:

        # of expected passes            151

The above results all use gcc, either the system gcc or a development
gcc (when testing against my OpenMP work in GDB).  I've also tested
with clang 9.0.0 and icc 19.0.5.281 20190815 on Fedora 31.

Fedora 31, clang:

FAIL: gdb.threads/omp-par-scope.exp: single_scope: first thread: print s1
FAIL: gdb.threads/omp-par-scope.exp: single_scope: first thread: print s3
FAIL: gdb.threads/omp-par-scope.exp: single_scope: first thread: print i1
FAIL: gdb.threads/omp-par-scope.exp: single_scope: first thread: print i3
FAIL: gdb.threads/omp-par-scope.exp: single_scope: second thread: print s1
FAIL: gdb.threads/omp-par-scope.exp: single_scope: second thread: print s3
FAIL: gdb.threads/omp-par-scope.exp: single_scope: second thread: print i1
FAIL: gdb.threads/omp-par-scope.exp: multi_scope: first thread: print i02
FAIL: gdb.threads/omp-par-scope.exp: multi_scope: first thread: print i11
FAIL: gdb.threads/omp-par-scope.exp: multi_scope: first thread: print i12
FAIL: gdb.threads/omp-par-scope.exp: multi_scope: first thread: print i22
FAIL: gdb.threads/omp-par-scope.exp: multi_scope: first thread: print file_scope_var
FAIL: gdb.threads/omp-par-scope.exp: multi_scope: second thread: print i11
FAIL: gdb.threads/omp-par-scope.exp: multi_scope: second thread: print file_scope_var
FAIL: gdb.threads/omp-par-scope.exp: multi_scope: after parallel: print file_scope_var
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 1st stop: print file_scope_var
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 1st stop: print num
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 1st stop: print l
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 1st stop: print k
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 2nd stop: print file_scope_var
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 2nd stop: print num
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 3rd stop: print file_scope_var
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 3rd stop: print num
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 3rd stop: print l
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 3rd stop: print k
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 4th stop: print file_scope_var
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 4th stop: print num
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: outer_threads: outer stop: print file_scope_var
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: outer_threads: outer stop: print i
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: outer_threads: outer stop: print j

Fedora 31, icc:

FAIL: gdb.threads/omp-par-scope.exp: multi_scope: first thread: print i12
FAIL: gdb.threads/omp-par-scope.exp: multi_scope: first thread: print i22
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 1st call: 1st thread: print s1
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 1st call: 1st thread: print i
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 1st call: 1st thread: print j
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 1st call: 2nd thread: print s1
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 1st call: 2nd thread: print i
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 1st call: 2nd thread: print j
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 1st call: 2nd thread: print k
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 1st call: 2nd thread: print z
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 2nd call: 1st thread: print s1
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 2nd call: 1st thread: print i
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 2nd call: 1st thread: print j
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 2nd call: 2nd thread: print s1
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 2nd call: 2nd thread: print i
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 2nd call: 2nd thread: print j
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 2nd call: 2nd thread: print k
FAIL: gdb.threads/omp-par-scope.exp: nested_func: 2nd call: 2nd thread: print z
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 1st stop: print l
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 1st stop: print k
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 3rd stop: print l
FAIL: gdb.threads/omp-par-scope.exp: nested_parallel: inner_threads: 3rd stop: print k

For both clang and icc, it turns out that there are some problems with
the DWARF that these compilers generate.  Of the two, icc does at
least nest the subprogram of the outlined function representing the
parallel region within the function that it's defined, but does not
handle inner scopes if they exist.  clang places the subprogram for
the outlined function at the same level as the containing function, so
variables declared within the function aren't visible at all.

I could call setup_xfail to avoid FAILs for clang and icc also, but I don't
want to further complicate the test.

gdb/testsuite/ChangeLog:

	* gdb.threads/omp-par-scope.c: New file.
	* gdb/threads/omp-par-scope.exp: New file.

Change-Id: Icb9c991730d84ca7509380af817dfcc778e764ea