Added spec for while loops.

lib/reversal/reverser.rb

@@ -123,22 +123,23 @@ def backward_jump?(current, label)
     end
 
     def next_instruction_number(cur_inst, cur_line)
-      if cur_inst.is_a?(Array) && (cur_inst[0] == :branchif || cur_inst[0] == :branchunless)
-        target = cur_inst[1]
-        location_of_target = @iseq.labels[target]
-        else_instruction = @iseq.body[location_of_target - 1]
-        if else_instruction.first == :jump
-          else_target = else_instruction[1]
-          location_of_else_target = @iseq.labels[else_target]
-          return location_of_else_target
-        else
+      if cur_inst.is_a?(Array)
+        if (cur_inst[0] == :branchif || cur_inst[0] == :branchunless) && forward_jump?(cur_line,cur_inst[1])
+          target = cur_inst[1]
+          location_of_target = @iseq.labels[target]
+          else_instruction = @iseq.body[location_of_target - 1]
+          if else_instruction.first == :jump
+            else_target = else_instruction[1]
+            location_of_else_target = @iseq.labels[else_target]
+            return location_of_else_target
+          else
+            return @iseq.body.size + 1
+          end
+        elsif cur_inst[0] == :leave
           return @iseq.body.size + 1
         end
-      elsif cur_inst.is_a?(Array) && (cur_inst[0] == :leave)
-        return @iseq.body.size + 1
-      else
-        return cur_line + 1
       end
+      return cur_line + 1
     end
 
     def decompile_body(instruction = @iseq.body_start, stop = @iseq.body.size)

spec/control_flow_spec.rb

@@ -112,6 +112,16 @@ def test(x)
     puts(x)
   end
 end
+RESULT
+
+    @simple_while = CompiledDecompilationTestCase.new <<CLASS, <<RESULT
+begin
+  x
+end while y
+CLASS
+begin
+  x
+end while y
 RESULT
   end
 
@@ -142,4 +152,8 @@ def test(x)
   it "can decompile a condition using the || operator" do
     @uses_oror.assert_correct
   end
+
+  it "can decompile simple do..while loops" do
+    @simple_while.assert_correct
+  end
 end