Optimize Marshal dump/load for large (> 31-bit) FIXNUM (#6229)

* Optimize Marshal dump of large fixnum

Marshal's FIXNUM type only supports 31-bit fixnums, so on 64-bit
platforms the 63-bit fixnums need to be represented in Marshal's
BIGNUM.

Previously this was done by converting to a bugnum and serializing the
bignum object.

This commit avoids allocating the intermediate bignum object, instead
outputting the T_FIXNUM directly to a Marshal bignum. This maintains the
same representation as the previous implementation, including not using
LINKs for these large fixnums (an artifact of the previous
implementation always allocating a new BIGNUM).

This commit also avoids unnecessary st_lookups on immediate values,
which we know will not be in that table.

* Fastpath for loading FIXNUM from Marshal bignum

* Run update-deps

1 files changed, 21 insertions, 1 deletions

diff --git a/test/ruby/test_marshal.rb b/test/ruby/test_marshal.rb
index 361d18dd4b..fc5cd9e93e 100644
--- a/test/ruby/test_marshal.rb
+++ b/test/ruby/test_marshal.rb
@@ -33,7 +33,7 @@ class TestMarshal < Test::Unit::TestCase
   end
 
   def test_marshal
-    a = [1, 2, 3, [4,5,"foo"], {1=>"bar"}, 2.5, fact(30)]
+    a = [1, 2, 3, 2**32, 2**64, [4,5,"foo"], {1=>"bar"}, 2.5, fact(30)]
     assert_equal a, Marshal.load(Marshal.dump(a))
 
     [[1,2,3,4], [81, 2, 118, 3146]].each { |w,x,y,z|
@@ -47,6 +47,26 @@ class TestMarshal < Test::Unit::TestCase
     }
   end
 
+  def test_marshal_integers
+    a = []
+    [-2, -1, 0, 1, 2].each do |i|
+      0.upto(65).map do |exp|
+        a << 2**exp + i
+      end
+    end
+    assert_equal a, Marshal.load(Marshal.dump(a))
+
+    a = [2**32, []]*2
+    assert_equal a, Marshal.load(Marshal.dump(a))
+
+    a = [2**32, 2**32, []]*2
+    assert_equal a, Marshal.load(Marshal.dump(a))
+  end
+
+  def test_marshal_small_bignum_backref
+    assert_equal [2**32, 2**32], Marshal.load("\x04\b[\al+\b\x00\x00\x00\x00\x01\x00@\x06")
+  end
+
   StrClone = String.clone
   def test_marshal_cloned_class
     assert_instance_of(StrClone, Marshal.load(Marshal.dump(StrClone.new("abc"))))