From 728d5439e3f5e812246237670f5d9dc9f0d97bae Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.de>
Date: Fri, 5 Aug 2022 16:12:56 +0200
Subject: [PATCH] [gdb] Add unit test for gdb::sequential_for_each

With commit 18a5766d09c ("[gdbsupport] Add sequential_for_each") I added a
drop-in replacement for gdb::parallel_for_each, but there's nothing making
sure that the two remain in sync.

Extend the unit test for gdb::parallel_for_each to test both.

Do this using a slightly unusual file-self-inclusion.  Doing so keep things
readable and maintainable, and avoids macrofying functions.

Tested on x86_64-linux.
---
 gdb/unittests/parallel-for-selftests.c | 133 +++++++++++++++----------
 1 file changed, 82 insertions(+), 51 deletions(-)

diff --git a/gdb/unittests/parallel-for-selftests.c b/gdb/unittests/parallel-for-selftests.c
index 6e341f64037..75c1deb17dc 100644
--- a/gdb/unittests/parallel-for-selftests.c
+++ b/gdb/unittests/parallel-for-selftests.c
@@ -17,6 +17,13 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
+/* This file is divided in two parts:
+   - FOR_EACH-undefined, and
+   - FOR_EACH-defined.
+   The former includes the latter, more than once, with different values for
+   FOR_EACH.  The FOR_EACH-defined part reads like a regular function.  */
+#ifndef FOR_EACH
+
 #include "defs.h"
 #include "gdbsupport/selftest.h"
 #include "gdbsupport/parallel-for.h"
@@ -43,60 +50,25 @@ struct save_restore_n_threads
   int n_threads;
 };
 
+/* Define test_par using TEST in the FOR_EACH-defined part.  */
+#define TEST test_par
+#define FOR_EACH gdb::parallel_for_each
+#include "parallel-for-selftests.c"
+#undef FOR_EACH
+#undef TEST
+
+/* Define test_seq using TEST in the FOR_EACH-defined part.  */
+#define TEST test_seq
+#define FOR_EACH gdb::sequential_for_each
+#include "parallel-for-selftests.c"
+#undef FOR_EACH
+#undef TEST
+
 static void
 test (int n_threads)
 {
-  save_restore_n_threads saver;
-  gdb::thread_pool::g_thread_pool->set_thread_count (n_threads);
-
-#define NUMBER 10000
-
-  std::atomic<int> counter (0);
-  gdb::parallel_for_each (1, 0, NUMBER,
-			  [&] (int start, int end)
-			  {
-			    counter += end - start;
-			  });
-
-  SELF_CHECK (counter == NUMBER);
-
-  counter = 0;
-  gdb::parallel_for_each (1, 0, 0,
-			  [&] (int start, int end)
-			  {
-			    counter += end - start;
-			  });
-  SELF_CHECK (counter == 0);
-
-  auto task_size_max_ = [] (int iter)
-    {
-      return (size_t)SIZE_MAX;
-    };
-  auto task_size_max = gdb::make_function_view (task_size_max_);
-
-  counter = 0;
-  gdb::parallel_for_each (1, 0, NUMBER,
-			  [&] (int start, int end)
-			  {
-			    counter += end - start;
-			  }, task_size_max);
-  SELF_CHECK (counter == NUMBER);
-
-  auto task_size_one_ = [] (int iter)
-    {
-      return (size_t)1;
-    };
-  auto task_size_one = gdb::make_function_view (task_size_one_);
-
-  counter = 0;
-  gdb::parallel_for_each (1, 0, NUMBER,
-			  [&] (int start, int end)
-			  {
-			    counter += end - start;
-			  }, task_size_one);
-  SELF_CHECK (counter == NUMBER);
-
-#undef NUMBER
+  test_par (n_threads);
+  test_seq (n_threads);
 }
 
 static void
@@ -121,3 +93,62 @@ _initialize_parallel_for_selftests ()
 			    selftests::parallel_for::test_n_threads);
 #endif /* CXX_STD_THREAD */
 }
+
+#else /* FOR_EACH */
+
+static void
+TEST (int n_threads)
+{
+  save_restore_n_threads saver;
+  gdb::thread_pool::g_thread_pool->set_thread_count (n_threads);
+
+#define NUMBER 10000
+
+  std::atomic<int> counter (0);
+  FOR_EACH (1, 0, NUMBER,
+	    [&] (int start, int end)
+	    {
+	      counter += end - start;
+	    });
+  SELF_CHECK (counter == NUMBER);
+
+  counter = 0;
+  FOR_EACH (1, 0, 0,
+	    [&] (int start, int end)
+	    {
+	      counter += end - start;
+	    });
+  SELF_CHECK (counter == 0);
+
+  auto task_size_max_ = [] (int iter)
+    {
+      return (size_t)SIZE_MAX;
+    };
+  auto task_size_max = gdb::make_function_view (task_size_max_);
+
+  counter = 0;
+  FOR_EACH (1, 0, NUMBER,
+	    [&] (int start, int end)
+	    {
+	      counter += end - start;
+	    }, task_size_max);
+  SELF_CHECK (counter == NUMBER);
+
+  auto task_size_one_ = [] (int iter)
+    {
+      return (size_t)1;
+    };
+  auto task_size_one = gdb::make_function_view (task_size_one_);
+
+  counter = 0;
+  FOR_EACH (1, 0, NUMBER,
+	    [&] (int start, int end)
+	    {
+	      counter += end - start;
+	    }, task_size_one);
+  SELF_CHECK (counter == NUMBER);
+
+#undef NUMBER
+}
+
+#endif /* FOR_EACH */