When thinking about GOMP_teams3, I've realized that using global variables
for the values returned by omp_get_num_teams()/omp_get_team_num() calls
is incorrect even with our right now dumb way of implementing host teams.
The problems are two, one is if host teams is used from multiple pthread_create
created threads - the spec says that host teams can't be nested inside of
explicit parallel or other teams constructs, but with pthread_create the
standard says obviously nothing about it.  Another more important thing
is host fallback, right now we don't do anything for omp_get_num_teams()
or omp_get_team_num() which was fine before host teams was introduced and
the 5.1 requirement that num_teams clause specifies minimum of teams, but
with the global vars it means inside of target teams num_teams (2) we happily
return omp_get_num_teams() == 4 if the target teams is inside of host teams
with num_teams(4).  With target fallback being invoked from parallel
regions global vars simply can't work right on the host.

So, this patch moves them to struct gomp_thread and propagates those for
parallel to child threads.  For host fallback, the implicit zeroing of
*thr results in us returning omp_get_num_teams () == 1 and
omp_get_team_num () == 0 which is fine for target teams without num_teams
clause, for target teams with num_teams clause something to work on and
for target without teams nested in it I've asked on omp-lang what should
be done.

2021-11-11  Jakub Jelinek  <jakub@redhat.com>

	* libgomp.h (struct gomp_thread): Add num_teams and team_num members.
	* team.c (struct gomp_thread_start_data): Likewise.
	(gomp_thread_start): Initialize thr->num_teams and thr->team_num.
	(gomp_team_start): Initialize start_data->num_teams and
	start_data->team_num.  Update nthr->num_teams and nthr->team_num.
	* teams.c (gomp_num_teams, gomp_team_num): Remove.
	(GOMP_teams_reg): Set and restore thr->num_teams and thr->team_num
	instead of gomp_num_teams and gomp_team_num.
	(omp_get_num_teams): Use thr->num_teams + 1 instead of gomp_num_teams.
	(omp_get_team_num): Use thr->team_num instead of gomp_team_num.
	* testsuite/libgomp.c/teams-4.c: New test.

OpenMP 5.1 adds env vars and functions to set and query new ICVs used
as fallback if thread_limit or num_teams clauses aren't specified on
teams construct.

The following patch implements those, though further work will be needed:
1) OpenMP 5.1 also changed the num_teams clause, so that it can specify
   both lower and upper limit for how many teams should be created and
   changed the meaning when only one expression is provided, instead of
   num_teams(expr) in 5.0 meaning num_teams(1:expr) in 5.1, it now means
   num_teams(expr:expr), i.e. while previously we could create 1 to expr
   teams, in 5.1 we have some low limit by default equal to the single
   expression provided and may not create fewer teams.
   For host teams (which we don't currently implement efficiently for
   NUMA hosts) we trivially satisfy it now by always honoring what the
   user asked for, but for the offloading teams I think we'll need to
   rethink the APIs; currently teams construct is just a call that returns
   and possibly lowers the number of teams; and whenever possible we try
   to evaluate num_teams/thread_limit already on the target construct
   and the GOMP_teams call just sets the number of teams to the minimum
   of provided and requested teams; for some cases e.g. where target
   is not combined with teams and num_teams expression calls some functions
   etc., we need to call those functions in the target region and so it is
   late to figure number of teams, but also hw could just limit what it
   is willing to create; in that case I'm afraid we need to run the target
   body multiple times and arrange for omp_get_team_num () returning the
   right values
2) we need to finally implement the NUMA handling for GOMP_teams_reg
3) I now realize I haven't added some testcase coverage, will do that
   incrementally
4) libgomp.texi needs updates for these new APIs, but also others like
   the allocator

2021-10-11  Jakub Jelinek  <jakub@redhat.com>

gcc/
	* omp-low.c (omp_runtime_api_call): Handle omp_get_max_teams,
	omp_[sg]et_teams_thread_limit and omp_set_num_teams.
libgomp/
	* omp.h.in (omp_set_num_teams, omp_get_max_teams,
	omp_set_teams_thread_limit, omp_get_teams_thread_limit): Declare.
	* omp_lib.f90.in (omp_set_num_teams, omp_get_max_teams,
	omp_set_teams_thread_limit, omp_get_teams_thread_limit): Declare.
	* omp_lib.h.in (omp_set_num_teams, omp_get_max_teams,
	omp_set_teams_thread_limit, omp_get_teams_thread_limit): Declare.
	* libgomp.h (gomp_nteams_var, gomp_teams_thread_limit_var): Declare.
	* libgomp.map (OMP_5.1): Export omp_get_max_teams{,_},
	omp_get_teams_thread_limit{,_}, omp_set_num_teams{,_,_8_} and
	omp_set_teams_thread_limit{,_,_8_}.
	* icv.c (omp_set_num_teams, omp_get_max_teams,
	omp_set_teams_thread_limit, omp_get_teams_thread_limit): New
	functions.
	* env.c (gomp_nteams_var, gomp_teams_thread_limit_var): Define.
	(omp_display_env): Print OMP_NUM_TEAMS and OMP_TEAMS_THREAD_LIMIT.
	(initialize_env): Handle OMP_NUM_TEAMS and OMP_TEAMS_THREAD_LIMIT env
	vars.
	* teams.c (GOMP_teams_reg): If thread_limit is not specified, use
	gomp_teams_thread_limit_var as fallback if not zero.  If num_teams
	is not specified, use gomp_nteams_var.
	* fortran.c (omp_set_num_teams, omp_get_max_teams,
	omp_set_teams_thread_limit, omp_get_teams_thread_limit): Add
	ialias_redirect.
	(omp_set_num_teams_, omp_set_num_teams_8_, omp_get_max_teams_,
	omp_set_teams_thread_limit_, omp_set_teams_thread_limit_8_,
	omp_get_teams_thread_limit_): New functions.

From-SVN: r279813

From-SVN: r267494

	* affinity.c: Include <string.h>, <stdio.h>.
	(gomp_display_affinity_place): Remove cpusetp.
	* teams.c: Include <limits.h>.

From-SVN: r265938