Implement GC count

Author: wks

gc/default/default.c

@@ -7947,6 +7947,10 @@ gc_count_add_each_types(VALUE hash, const char *name, const size_t *types)
 size_t
 rb_gc_impl_gc_count(void *objspace_ptr)
 {
+    WHEN_USING_MMTK({
+        return rb_mmtk_gc_count();
+    })
+
     rb_objspace_t *objspace = objspace_ptr;
 
     return objspace->profile.count;

internal/mmtk_support.h

@@ -117,6 +117,9 @@ void rb_mmtk_assert_is_pinned(VALUE obj);
 void rb_mmtk_shutdown_gc_threads(void);
 void rb_mmtk_respawn_gc_threads(void);
 
+// GC module and information (GC)
+size_t rb_mmtk_gc_count(void);
+
 // MMTk-specific Ruby module (GC::MMTk)
 void rb_mmtk_define_gc_mmtk_module(void);
 VALUE rb_mmtk_plan_name(VALUE _);

mmtk_support.c

@@ -1252,6 +1252,17 @@ void rb_mmtk_respawn_gc_threads(void)
     mmtk_after_fork(GET_THREAD());
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// GC module and information (GC)
+////////////////////////////////////////////////////////////////////////////////
+
+// Return the number of GCs happened since the program started.
+size_t
+rb_mmtk_gc_count(void)
+{
+    return rb_mmtk_global.start_the_world_count;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // MMTk-specific Ruby module (GC::MMTk)
 ////////////////////////////////////////////////////////////////////////////////

test/.excludes-mmtk/TestGc.rb

@@ -1,5 +1,3 @@
-exclude(:test_count, "GC count not yet implemented")
-exclude(:test_gc_disabled_start, "GC count not yet implemented")
 exclude(:test_expand_heap, "testing behaviour specific to default GC")
 exclude(:test_gc_config_disable_major, "testing behaviour specific to default GC")
 exclude(:test_gc_config_disable_major_gc_start_always_works, "testing behaviour specific to default GC")
@@ -24,5 +22,4 @@
 exclude(:test_stat_heap, "testing behaviour specific to default GC")
 exclude(:test_stat_heap_all, "testing behaviour specific to default GC")
 exclude(:test_stat_heap_constraints, "testing behaviour specific to default GC")
-exclude(:test_stat_single, "GC count not yet implemented.  Actually GC can be triggered between evaluation.")
 exclude(:test_thrashing_for_young_objects, "testing behaviour specific to default GC")