[openmp] [test] Unbreak tests that rely on hidden_helper_task on Windows

[mstorsjo]

Summary

The hidden helper task is only enabled on Linux (kmp_runtime.cpp
initializes kmp_enable_hidden_helper to TRUE for linux but to
FALSE for any other OS), and the kmp_stg_parse_use_hidden_helper
function always makes it disabled on non-Linux OSes too.

Mark tests that rely on the hidden helper tasks as requiring Linux.

Set the initial value of __kmp_hidden_helper_threads_num accordingly
in a testcase that needs to know it.

[mstorsjo]

@jlpeyton Does this look like the right way to go?

[jlpeyton]

A few suggestions

openmp/runtime/test/tasking/hidden_helper_task/affinity.cpp

2

For these tests affinity.cpp and gtid.cpp, it seems appropriate to create a new Linux-only feature inside openmp/runtime/test/lit.cfg called hidden-helper (or something like it) and use that instead. It would fit best at around line 110 near where the affinity and some other features are added.

openmp/runtime/test/worksharing/for/kmp_sch_simd_guided.c

53–57

It's probably better to disable hidden helper threads since they aren't participating in this test.

You can modify the run line to
RUN: %libomp-compile && env LIBOMP_USE_HIDDEN_HELPER_TASK=0 LIBOMP_NUM_HIDDEN_HELPER_THREADS=0 %libomp-run

And also set static int __kmp_hidden_helper_threads_num = 0.

[mstorsjo]

Updated according to suggestions.

[mstorsjo]

Thanks for the suggestions!

openmp/runtime/test/tasking/hidden_helper_task/affinity.cpp

2

Sure, done.

openmp/runtime/test/worksharing/for/kmp_sch_simd_guided.c

53–57

Ah, thanks! Yes that's probably better here. (I guess one could remove the whole logic for counting hidden helper threads here too, but I kept it and just set it to zero for now.)

[jlpeyton]

Thanks for the fixes! LGTM.

openmp/runtime/test/lit.cfg

if 'Linux' in config.operating_system:
     config.available_features.add("linux")
 
 if config.operating_system == 'NetBSD':
     config.available_features.add("netbsd")
 
 if config.operating_system in ['Linux', 'Windows']:
     config.available_features.add('affinity')
 
+if config.operating_system in ['Linux']:
+    config.available_features.add('hidden-helper')
+
 import multiprocessing
 try:
     if multiprocessing.cpu_count() > 1:
         config.available_features.add('multicpu')
 except NotImplementedError:
     pass
 
 # to run with icc INTEL_LICENSE_FILE must be set

openmp/runtime/test/tasking/hidden_helper_task/affinity.cpp

+// REQUIRES: hidden-helper
 // RUN: %libomp-cxx-compile
 // RUN: env LIBOMP_USE_HIDDEN_HELPER_TASK=1 LIBOMP_NUM_HIDDEN_HELPER_THREADS=8 \
 // RUN:     KMP_HIDDEN_HELPER_AFFINITY=verbose,granularity=socket,compact %libomp-run 2>&1 | FileCheck --check-prefix=SOCKET %s
 // RUN: env LIBOMP_USE_HIDDEN_HELPER_TASK=1 LIBOMP_NUM_HIDDEN_HELPER_THREADS=8 \
 // RUN:     KMP_HIDDEN_HELPER_AFFINITY=verbose,granularity=core,scatter %libomp-run 2>&1 | FileCheck --check-prefix=CORE %s
 // RUN: env LIBOMP_USE_HIDDEN_HELPER_TASK=1 LIBOMP_NUM_HIDDEN_HELPER_THREADS=8 \
 // RUN:     KMP_HIDDEN_HELPER_AFFINITY='verbose,granularity=fine,explicit,proclist=[0,1]' %libomp-run 2>&1 | FileCheck --check-prefix=FINE %s
 // RUN: env LIBOMP_USE_HIDDEN_HELPER_TASK=1 LIBOMP_NUM_HIDDEN_HELPER_THREADS=8 \
 // RUN:     KMP_HIDDEN_HELPER_AFFINITY=verbose,granularity=socket,compact KMP_AFFINITY=compact,granularity=fine %libomp-run 2>&1 | FileCheck --check-prefix=SOCKET %s

openmp/runtime/test/tasking/hidden_helper_task/gtid.cpp

 // RUN: %libomp-cxx-compile-and-run
 // RUN: %libomp-cxx-compile && env OMP_NUM_THREADS=1 %libomp-run
+// REQUIRES: hidden-helper
 
 /*
  * This test aims to check whether hidden helper thread has right gtid. We also
  * test if there is mixed dependences between regular tasks and hidden helper
  * tasks, the tasks are executed by right set of threads. It is equivalent to
  * the following code:
  *
  * #pragma omp parallel for

openmp/runtime/test/worksharing/for/kmp_sch_simd_guided.c

-// RUN: %libomp-compile-and-run
+// RUN: %libomp-compile && env LIBOMP_USE_HIDDEN_HELPER_TASK=0 LIBOMP_NUM_HIDDEN_HELPER_THREADS=0 %libomp-run
 /*
   Test for the 'schedule(simd:guided)' clause.
   Compiler needs to generate a dynamic dispatching and pass the schedule
   value 46 to the OpenMP RTL. Test uses numerous loop parameter combinations.
 */
 #include <stdio.h>
 #include <stdlib.h>
 #include <omp.h>

 extern void __kmpc_dispatch_init_8(id*, int, enum sched, i64, i64, i64, i64);
 extern int __kmpc_dispatch_next_4(id*, int, void*, void*, void*, void*);
 extern int __kmpc_dispatch_next_8(id*, int, void*, void*, void*, void*);
 // End of definitions copied from OpenMP RTL.
 // ---------------------------------------------------------------------------
 static id loc = {0, 2, 0, 0, ";file;func;0;0;;"};
 // This variable is defined in OpenMP RTL but we can't have it exposed so we
 // need to redefine it here.
-static int __kmp_hidden_helper_threads_num = 8;
+static int __kmp_hidden_helper_threads_num = 0;
 
 // ---------------------------------------------------------------------------
 int run_loop_64(i64 loop_lb, i64 loop_ub, i64 loop_st, int loop_chunk) {
   int err = 0;
   static int volatile loop_sync = 0;
   i64 lb;   // Chunk lower bound
   i64 ub;   // Chunk upper bound
   i64 st;   // Chunk stride
   int rc;
   int tid = omp_get_thread_num();
   int gtid = tid;
   if (gtid) {