re-implemented jumpreturn via exception (we have to pop from MRI st…

…ack)

executor.rb

@@ -837,7 +837,7 @@ def _do_throw(throw_obj)
     if throw_obj.is_a?(Exception)
       raise throw_obj
     else
-      # raise VM::LocalJumpError.new(throw_obj)
+      binding.irb
     end
   end
 
@@ -851,14 +851,7 @@ def execute_throw((throw_state))
       case state
       when 1
         # return
-        frame = current_frame
-
-        until frame.can_return?
-          frame.exit!(:__unused)
-          frame = frame.parent_frame
-        end
-
-        frame.exit!(throw_obj)
+        raise VM::ReturnError, throw_obj
       when 3
         # next inside rescue/ensure, inside pop_frame,
         # so current_frame is about to die

spec/vm_spec.rb

@@ -183,9 +183,9 @@ def test
   it 'supports longjmp via return' do
     assert_evaluates_like_mri(<<-RUBY)
       def m
-        [1].each do |x|
-          [2].each do |y|
-            [3].each do |z|
+        [1, 10].each do |x|
+          [2, 20].each do |y|
+            [3, 30].each do |z|
               return [x,y,z]
             end
           end

vm.rb

@@ -9,20 +9,27 @@ class VM
   attr_accessor :debug_print_stack
   attr_accessor :debug_print_rest_on_error
 
-  class LocalJumpError < ::LocalJumpError
+  class InternalError < ::Exception
+    def initialize(*)
+      super
+      set_backtrace(VM.instance.backtrace)
+    end
+  end
+
+  class MessageError  < InternalError
+    attr_reader :value
+
     def initialize(value)
       @value = value
     end
-    attr_reader :value
-  end
 
-  class InternalError < ::RuntimeError
-    def initialize(*)
-      super
-      set_backtrace(VM.instance.backtrace)
+    def message
+      "#{self.class}(#{@value.inspect})"
     end
   end
 
+  class ReturnError < MessageError; end
+
   def initialize
     @frame_stack = FrameStack.new
     # @frame_stack.singleton_class.prepend(Module.new {
@@ -54,12 +61,27 @@ def execute(iseq, **payload)
     if (before_eval = payload[:before_eval]); before_eval.call; end
 
     __log { "\n\n--------- BEGIN #{current_frame.header} ---------" }
-    evaluate_last_frame
+
+    begin
+      evaluate_last_frame
+    rescue ReturnError => e
+      raise unless current_frame.can_return?
+
+      frame = current_frame
+
+      until frame.can_return?
+        frame.exit!(:__unused)
+        frame = frame.parent_frame
+      end
+
+      frame.exit!(e.value)
+    end
+
     __log { "\n\n--------- END   #{current_frame.header} ---------" }
   ensure
     result = pop_frame
 
-    if $! && $!.is_a?(InternalError)
+    if $!
       raise
     end
 
@@ -188,15 +210,7 @@ def evaluate_last_frame
 
       current_insn = current_iseq.shift_insn
 
-      begin
-        execute_insn(current_insn)
-      rescue
-        if debug_print_rest_on_error
-          $debug.puts "--------------\nRest (for #{current_frame.pretty_name} in #{current_frame.file}):"
-          current_iseq.insns.each { |insn| p insn }
-        end
-        raise
-      end
+      execute_insn(current_insn)
     end
   end
 
@@ -272,12 +286,9 @@ def execute_array_insn(insn)
 
   def with_error_handling
     yield
+  rescue InternalError => e
+    raise
   rescue Exception => e
-    if e.is_a?(InternalError)
-      # our error, just re-raise ie
-      raise
-    end
-
     # error from the inerpreted code
     clear_current_iseq
     current_frame.current_error = e

vm/frames/factory.rb

@@ -71,6 +71,7 @@ def has_returning?
 
       def exit!(value)
         VM.instance.__log { "... scheduling force [:leave] (on #{self.name} with #{value.inspect})" }
+        @returning = value
 
         iseq.insns.clear
         iseq.insns.push([:leave])

vm/stack.rb

@@ -29,6 +29,10 @@ def pop
     @stack.pop
   end
 
+  def empty?
+    @stack.empty?
+  end
+
   def top
     @stack.last
   end