Use a monotonically increasing number for object_id

This changes object_id from being based on the objects location in
memory (or a nearby memory location in the case of a conflict) to be
based on an always increasing number.

This number is a Ruby Integer which allows it to overflow the size of a
pointer without issue (very unlikely to happen in real programs
especially on 64-bit, but a nice guarantee).

This changes obj_to_id_tbl and id_to_obj_tbl to both be maps of Ruby
objects to Ruby objects (previously they were Ruby object to C integer)
which simplifies updating them after compaction as we can run them
through gc_update_table_refs.

Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>

1 files changed, 0 insertions, 90 deletions

diff --git a/test/ruby/test_gc_compact.rb b/test/ruby/test_gc_compact.rb
index eaffccda08..bc26897386 100644
--- a/test/ruby/test_gc_compact.rb
+++ b/test/ruby/test_gc_compact.rb
@@ -7,13 +7,6 @@ class TestGCCompact < Test::Unit::TestCase
     (Fiddle.dlwrap(obj) >> 1)
   end
 
-  def assert_object_ids(list)
-    same_count = list.find_all { |obj|
-      memory_location(obj) == obj.object_id
-    }.count
-    list.count - same_count
-  end
-
   def big_list(level = 10)
     if level > 0
       big_list(level - 1)
@@ -41,89 +34,6 @@ class TestGCCompact < Test::Unit::TestCase
     new_object
   end
 
-  def try_to_move_objects
-    10.times do
-      list_of_objects = big_list
-
-      ids       = list_of_objects.map(&:object_id) # store id in map
-      addresses = list_of_objects.map(&self.:memory_location)
-
-      assert_equal ids, addresses
-
-      # All object ids should be equal
-      assert_equal 0, assert_object_ids(list_of_objects) # should be 0
-
-      GC.verify_compaction_references(toward: :empty)
-
-      # Some should have moved
-      id_count = assert_object_ids(list_of_objects)
-      skip "couldn't get objects to move" if id_count == 0
-      assert_operator id_count, :>, 0
-
-      new_ids = list_of_objects.map(&:object_id)
-
-      # Object ids should not change after compaction
-      assert_equal ids, new_ids
-
-      new_tenant = find_object_in_recycled_slot(addresses)
-      return [list_of_objects, addresses, new_tenant] if new_tenant
-    end
-
-    flunk "Couldn't get objects to move"
-  end
-
-  def test_find_collided_object
-    skip "figure out how to guarantee move"
-
-    list_of_objects, addresses, new_tenant = try_to_move_objects
-
-    # This is the object that used to be in new_object's position
-    loc = memory_location(new_tenant)
-    assert loc, "should have a memory location"
-
-    if (ENV['TRAVIS'] && RUBY_PLATFORM =~ /darwin/)
-      skip "tests are failing on Travis osx / Wercker from here"
-    end
-
-    address_idx = addresses.index(loc)
-    assert address_idx, "should have an address index"
-
-    previous_tenant = list_of_objects[address_idx]
-    assert previous_tenant, "should have a previous tenant"
-
-    assert_not_equal previous_tenant.object_id, new_tenant.object_id
-
-    # Should be able to look up object by object_id
-    assert_equal new_tenant, ObjectSpace._id2ref(new_tenant.object_id)
-
-    # Should be able to look up object by object_id
-    assert_equal previous_tenant, ObjectSpace._id2ref(previous_tenant.object_id)
-
-    int = (new_tenant.object_id >> 1)
-    # These two should be the same! but they are not :(
-    assert_equal int, ObjectSpace._id2ref(int.object_id)
-  end
-
-  def test_many_collisions
-    list_of_objects = big_list
-    ids       = list_of_objects.map(&:object_id)
-    addresses = list_of_objects.map(&self.:memory_location)
-
-    GC.verify_compaction_references(toward: :empty)
-
-    skip "time consuming"
-
-    new_tenants = 10.times.map {
-      find_object_in_recycled_slot(addresses)
-    }
-
-    collisions = GC.stat(:object_id_collisions)
-    skip "couldn't get objects to collide" if collisions == 0
-    assert_operator collisions, :>, 0
-    ids.clear
-    new_tenants.clear
-  end
-
   def test_complex_hash_keys
     list_of_objects = big_list
     hash = list_of_objects.hash