give labels an integer that will end up being the position at runtime

Since integers are first class objects, we need to use an integer object
as the return address. The actual address can not be stored in an
instance variable since it is not an object.
The address is unique to the label and never changes after positioning
(using the int is next up)

test/risc/position/test_code_position.rb

@@ -7,7 +7,7 @@ module Risc
       Risc.machine.boot
       @binary = Parfait::BinaryCode.new(1)
       @method = Parfait.object_space.types.values.first.methods
-      @label = Label.new("hi","ho")
+      @label = Risc.label("hi","ho")
     end
     def test_set_bin
       pos = Position.set( @binary , 0 , @method)
@@ -29,7 +29,7 @@ module Risc
       machine.translate(:interpreter)
       @binary = Parfait::BinaryCode.new(1)
       @method = Parfait.object_space.types.values.first.methods
-      @label = Label.new("hi","ho")
+      @label = Risc.label("hi","ho")
     end
 
     def test_bin_propagates_existing

test/risc/position/test_instruction_position.rb

@@ -8,7 +8,7 @@ module Risc
         Risc.machine.boot
         @binary = Parfait::BinaryCode.new(1)
         Position.set(@binary , 0 , Parfait.object_space.get_main)
-        @label = Label.new("hi","ho")
+        @label = Risc.label("hi","ho")
       end
       def test_set_instr
         pos = Position.set( @label , 8 , @binary)

test/risc/test_builder.rb

@@ -7,7 +7,7 @@ module Risc
       Risc.machine.boot
       init = Parfait.object_space.get_init
       @builder = Risc::MethodCompiler.new( init ).builder(false , init)
-      @label = Risc::Label.new("source","name")
+      @label = Risc.label("source","name")
     end
     def test_has_build
       assert @builder.respond_to?(:build)

test/risc/test_instructions.rb

@@ -3,7 +3,7 @@ require_relative "../helper"
 module Risc
   class TestInstructions < MiniTest::Test
     def setup
-      @label = Label.new("test" , "test")
+      @label = Label.new("test" , "test",nil)
       @branch = Branch.new("test" , @label)
       @instruction = Instruction.new("test")
     end
@@ -19,7 +19,7 @@ module Risc
       assert @label.to_s.include?("Label")
     end
     def test_label_tos2
-      assert Label.new(nil,nil).to_s.include?("Label")
+      assert Label.new(nil,nil,nil).to_s.include?("Label")
     end
     def test_last_empty
       assert_equal @instruction, @instruction.last
@@ -55,7 +55,7 @@ module Risc
       assert_nil  @instruction.next(2)
     end
     def test_label_is_method
-      label = Label.new("test" , "Object.test")
+      label = Label.new("test" , "Object.test" , nil)
       assert label.is_method
     end
     def test_label_is_not_method

test/risc/test_interpreter_platform.rb

@@ -26,7 +26,7 @@ module Risc
     end
 
     def test_load_translates_label
-      label = Label.new("test" , "test")
+      label = Risc.label("test" , "test",nil)
       load = Risc.load_constant("source" , label , :r1)
       translated = @translator.translate(load)
       assert label != translated.constant