nitvm: The interpreter and the vm have each their own specialized frames

[nit.git] / src / interpreter / naive_interpreter.nit

diff --git a/src/interpreter/naive_interpreter.nit b/src/interpreter/naive_interpreter.nit
index dd61428..311d917 100644 (file)
--- a/src/interpreter/naive_interpreter.nit
+++ b/src/interpreter/naive_interpreter.nit
@@ -115,7 +115,7 @@ class NaiveInterpreter
 
        # Is a return executed?
        # Set this mark to skip the evaluation until the end of the specified method frame
-       var returnmark: nullable Frame = null
+       var returnmark: nullable FRAME = null
 
        # Is a break or a continue executed?
        # Set this mark to skip the evaluation until a labeled statement catch it with `is_escape`
@@ -283,11 +283,14 @@ class NaiveInterpreter
                return res
        end
 
+       # The virtual type of the frames used in the execution engine
+       type FRAME: Frame
+
        # The current frame used to store local variables of the current method executed
-       fun frame: Frame do return frames.first
+       fun frame: FRAME do return frames.first
 
        # The stack of all frames. The first one is the current one.
-       var frames = new List[Frame]
+       var frames = new List[FRAME]
 
        # Return a stack trace. One line per function
        fun stack_trace: String
@@ -314,6 +317,15 @@ class NaiveInterpreter
                return frames.first.arguments.first.mtype.as(MClassType)
        end
 
+       # Initialize the environment for a call and return a new Frame
+       # *`node` The AST node
+       # *`mpropdef` The corresponding mpropdef
+       # *`args` Arguments of the call
+       fun new_frame(node: ANode, mpropdef: MPropDef, args: Array[Instance]): FRAME
+       do
+               return new InterpreterFrame(node, mpropdef, args)
+       end
+
        # Exit the program with a message
        fun fatal(message: String)
        do
@@ -340,14 +352,14 @@ class NaiveInterpreter
        # Retrieve the value of the variable in the current frame
        fun read_variable(v: Variable): Instance
        do
-               var f = frames.first
+               var f = frames.first.as(InterpreterFrame)
                return f.map[v]
        end
 
        # Assign the value of the variable in the current frame
        fun write_variable(v: Variable, value: Instance)
        do
-               var f = frames.first
+               var f = frames.first.as(InterpreterFrame)
                f.map[v] = value
        end
 
@@ -415,7 +427,7 @@ class NaiveInterpreter
                var node = modelbuilder.mpropdef2node(mpropdef)
                if mpropdef.is_abstract then
                        if node != null then
-                               self.frames.unshift new Frame(node, mpropdef, args)
+                               self.frames.unshift new_frame(node, mpropdef, args)
                        end
                        fatal("Abstract method `{mpropdef.mproperty.name}` called on `{args.first.mtype}`")
                        abort
@@ -667,7 +679,7 @@ class PrimitiveInstance[E]
 end
 
 # Information about local variables in a running method
-class Frame
+abstract class Frame
        # The current visited node
        # The node is stored by frame to keep a stack trace
        var current_node: ANode
@@ -676,9 +688,16 @@ class Frame
        var mpropdef: MPropDef
        # Arguments of the method (the first is the receiver)
        var arguments: Array[Instance]
+       # Indicate if the expression has an array comprehension form
+       var comprehension: nullable Array[Instance] = null
+end
+
+# Implementation of a Frame with a Hashmap to store local variables
+class InterpreterFrame
+       super Frame
+
        # Mapping between a variable and the current value
        private var map: Map[Variable, Instance] = new HashMap[Variable, Instance]
-       var comprehension: nullable Array[Instance] = null
 end
 
 redef class ANode
@@ -711,7 +730,7 @@ redef class AMethPropdef
 
        redef fun call(v, mpropdef, args)
        do
-               var f = new Frame(self, self.mpropdef.as(not null), args)
+               var f = v.new_frame(self, mpropdef, args)
                var res = call_commons(v, mpropdef, args, f)
                v.frames.shift
                if v.returnmark == f then
@@ -1148,7 +1167,8 @@ redef class AAttrPropdef
                if mpropdef == mreadpropdef then
                        assert args.length == 1
                        if not is_lazy or v.isset_attribute(attr, recv) then return v.read_attribute(attr, recv)
-                       return evaluate_expr(v, recv)
+                       var f = v.new_frame(self, mpropdef, args)
+                       return evaluate_expr(v, recv, f)
                else if mpropdef == mwritepropdef then
                        assert args.length == 2
                        v.write_attribute(attr, recv, args[1])
@@ -1163,7 +1183,8 @@ redef class AAttrPropdef
        do
                if is_lazy then return
                if has_value then
-                       evaluate_expr(v, recv)
+                       var f = v.new_frame(self, mpropdef.as(not null), [recv])
+                       evaluate_expr(v, recv, f)
                        return
                end
                var mpropdef = self.mpropdef
@@ -1175,10 +1196,9 @@ redef class AAttrPropdef
                end
        end
 
-       private fun evaluate_expr(v: NaiveInterpreter, recv: Instance): Instance
+       private fun evaluate_expr(v: NaiveInterpreter, recv: Instance, f: Frame): Instance
        do
                assert recv isa MutableInstance
-               var f = new Frame(self, self.mpropdef.as(not null), [recv])
                v.frames.unshift(f)
 
                var val