Fix non ssa issue

register instances were being shared across instructions
causing the setting to have side-effects
Fixed this by copying the register on write
(fixing the symptom rather than the cause, i'll make an issue)

lib/risc/instructions/instruction.rb

@@ -60,12 +60,13 @@ module Risc
     # set all registers that has the name "name"
     # going through the register_names and setting all where the
     # get_register would return name
-    # Set to the value given as second arg.
+    # Create new RegisterValue with new name and swap the variable out
     def set_registers(name , value)
       register_attributes.each do |attr|
         reg = instance_variable_get("@#{attr}".to_sym)
         next unless reg.symbol == name
-        reg.set_name(value)
+        new_reg = reg.dup(value)
+        instance_variable_set("@#{attr}".to_sym , new_reg)
       end
     end
 

lib/risc/register_value.rb

@@ -23,13 +23,14 @@ module Risc
     # A third value may give extra information. This is a hash, where keys may
     # be :value, or :value_XX or :type_XX to indicate value or type information
     # for an XX instance
-    def initialize( reg , type , extra = {})
+    def initialize( reg , type , extra = {} , ssa = nil)
       extra = {} unless extra
-      @extra = extra
-      @symbol = reg
-      raise "not Symbol #{symbol}:#{symbol.class}" unless symbol.is_a?(Symbol)
       raise "Not Hash #{extra}"  unless extra.is_a?(Hash)
+      @extra = extra
+      raise "not Symbol #{reg}:#{reg.class}" unless reg.is_a?(Symbol)
+      @symbol = reg
       known_type(type)
+      @ssa = ssa
     end
 
     def class_name
@@ -37,17 +38,13 @@ module Risc
       @type.class_name
     end
 
-    # During initial creation ssa-like names are given to the registers.
-    # Later the name is changed, with set_name. When that happens
-    # the original is retained as ssa attttribute for debugging.
-    def set_name( symbol )
-      raise "not Symbol #{symbol}:#{symbol.class}" unless symbol.is_a?(Symbol)
-      old = @symbol
-      @ssa = @symbol
-      @symbol = symbol
-      old
+    # make a copy with a new register name (given arg)
+    # the copy will have the ssa set to the old name
+    def dup( reg )
+      RegisterValue.new(reg , @type , @extra , @symbol)
     end
 
+
     # allows to set the compiler, which is mainly done by the compiler
     # but sometimes, eg in exit, one nneds to create the reg by hand and set
     # return the RegisterValue for chaining in assignment

test/risc/test_register_value.rb

@@ -24,6 +24,11 @@ module Risc
     def test_r0
       assert_equal :message , @r0.symbol
     end
+    def test_dup
+      copy = @r0.dup( :r0 )
+      assert_equal :r0 , copy.symbol
+      assert_equal :message , copy.ssa
+    end
     def test_load_label
       label = Risc::Label.new("HI","ho" , FakeAddress.new(0))
       move = @r1 << label

test/risc/test_register_value1.rb

@@ -53,12 +53,5 @@ module Risc
     def test_has_ssa
       assert_nil @r0.ssa
     end
-    def test_set_name
-      assert_equal :message , @r0.set_name(:r0)
-    end
-    def test_set_ssa
-      @r0.set_name(:r0)
-      assert_equal :message , @r0.ssa
-    end
   end
 end

test/risc/test_standard_allocator1.rb

@@ -13,7 +13,7 @@ module Risc
     end
     def test_allocate_runs
       assert_nil @allocator.allocate_regs
-      #assert_equal 0 , @allocator.used_regs.length
+      assert_equal 0 , @allocator.used_regs.length
     end
     def test_live_length
       live = @allocator.walk_and_mark(@compiler.risc_instructions)