use the return jump to jump to the return sequence

thus every method only has one exit
should make multi return messages smaller
especially when we have escape analisis
(maybe will help with inlining too)

lib/parfait/callable_method.rb

@@ -1,14 +1,15 @@
-# A CallableMethod is static object that primarily holds the executable code.
-# It is callable through it's binary code
-# Additionally to the base class it has a name
-#
-# It's relation to the method a ruby programmer knows (called VoolMethod) is many to one,
-# meaning one VoolMethod (untyped) has many CallableMethod implementations.
-# The VoolMethod only holds vool code, no binary.
-
-
 module Parfait
 
+  # A CallableMethod is static object that primarily holds the executable code.
+  # It is callable through it's binary code
+  #
+  # It's relation to the method a ruby programmer knows (called VoolMethod) is many to one,
+  # meaning one VoolMethod (untyped) has many CallableMethod implementations.
+  # The VoolMethod only holds vool code, no binary.
+  #
+  # CallableMethods are bound to a known type (self_type) and have known argument
+  # and local variables. All variable resolution inside the method is exact (static),
+  # only method resolution may be dynamic
   class CallableMethod < Callable
 
     def ==(other)

lib/risc/callable_compiler.rb

@@ -13,14 +13,28 @@ module Risc
     def initialize( callable )
       @callable = callable
       @regs = []
-      @risc_instructions = Risc.label(source_name, source_name)
-      @risc_instructions << Risc.label( source_name, "unreachable")
+      init_instructions
       @current = @risc_instructions
       @constants = []
       @block_compilers = []
     end
     attr_reader :risc_instructions , :constants , :block_compilers , :callable
 
+    def init_instructions
+      @risc_instructions = Risc.label(source_name, source_name)
+      @risc_instructions.append Risc.label( source_name, "return_label")
+      @risc_instructions.append Mom::ReturnSequence.new.to_risc(self)
+      @risc_instructions.append Risc.label( source_name, "unreachable")
+      reset_regs
+    end
+
+    def return_label
+      @risc_instructions.each do |ins|
+        next unless ins.is_a?(Label)
+        return ins if ins.name == "return_label"
+      end
+    end
+
     # convert the given mom instruction to_risc and then add it (see add_code)
     # continue down the instruction chain unti depleted
     # (adding moves the insertion point so the whole mom chain is added as a risc chain)

lib/vool/return_statement.rb

@@ -18,7 +18,7 @@ module Vool
     def to_mom( compiler )
       ret = Mom::SlotLoad.new( [:message , :return_value] ,
                         @return_value.slot_definition(compiler) )
-      ret << Mom::ReturnSequence.new
+      ret << Mom::ReturnJump.new
     end
 
     def to_s(depth = 0)