* gc.c: Expose details about last garbage collection via GC.stat.

* gc.c (gc_stat): Add :last_collection_flags for reason/trigger/type of
  last GC run.
* gc.c (gc_prof_sweep_timer_stop): Record HAVE_FINALIZE GPR even
  without GC_PROFILE_MORE_DETAIL.
* gc.c (gc_profile_flags): Add GC::Profiler.decode_flags to make sense
  of GC.stat[:last_collection_flags]
* test/ruby/test_gc.rb (class TestGc): Test for above.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43893 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 20 insertions, 0 deletions

diff --git a/test/ruby/test_gc.rb b/test/ruby/test_gc.rb
index 0d101f609b..2668582ed8 100644
--- a/test/ruby/test_gc.rb
+++ b/test/ruby/test_gc.rb
@@ -79,6 +79,26 @@ class TestGc < Test::Unit::TestCase
     assert_equal(count[:FREE], stat[:heap_free_slot])
   end
 
+  def test_gc_reason
+    100_000.times{ "a" + "b" }
+    assert_equal({:gc_by => :newobj},
+      GC::Profiler.decode_flags(GC.stat[:last_collection_flags]))
+  end
+
+  def test_gc_reason_method
+    GC.start
+    assert_equal({:major_by=>:nofree, :gc_by=>:method, :immediate_sweep=>true},
+      GC::Profiler.decode_flags(GC.stat[:last_collection_flags]))
+  end
+
+  def test_gc_reason_stress
+    GC.stress = true
+    assert_equal({:major_by=>:stress, :gc_by=>:malloc, :immediate_sweep=>true},
+      GC::Profiler.decode_flags(GC.stat[:last_collection_flags]))
+  ensure
+    GC.stress = false
+  end
+
   def test_singleton_method
     assert_in_out_err(%w[--disable-gems], <<-EOS, [], [], "[ruby-dev:42832]")
       GC.stress = true