dart2js cps: Direct access on JS arrays.

pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 library dart2js.ir_nodes;
 
 import '../constants/values.dart' as values show ConstantValue;
 import '../dart_types.dart' show DartType, InterfaceType, TypeVariableType;
 import '../elements/elements.dart';
 import '../io/source_information.dart' show SourceInformation;
 import '../types/types.dart' show TypeMask;
@@ skipping 643 matching lines @@
 
   GetField(Primitive object, this.field)
       : this.object = new Reference<Primitive>(object);
 
   accept(Visitor visitor) => visitor.visitGetField(this);
 
   bool get isSafeForElimination => objectIsNotNull;
   bool get isSafeForReordering => objectIsNotNull && field.isFinal;
 }
 
+/// Get the length of a native list.
+class GetLength extends Primitive {
+  final Reference<Primitive> object;
+
+  /// True if the object is known not to be null.
+  bool objectIsNotNull = false;
+
+  GetLength(Primitive object) : this.object = new Reference<Primitive>(object);
+
+  bool get isSafeForElimination => objectIsNotNull;
+  bool get isSafeForReordering => false;
+
+  accept(Visitor v) => v.visitGetLength(this);
+}
+
+/// Read an entry from a native list.
+///
+/// [object] must be null or a native list, and [index] must be an integer.
+class GetIndex extends Primitive {
+  final Reference<Primitive> object;
+  final Reference<Primitive> index;
+
+  /// True if the object is known not to be null.
+  bool objectIsNotNull = false;
+
+  GetIndex(Primitive object, Primitive index)
+      : this.object = new Reference<Primitive>(object),
+        this.index = new Reference<Primitive>(index);
+
+  bool get isSafeForElimination => objectIsNotNull;
+  bool get isSafeForReordering => false;
+
+  accept(Visitor v) => v.visitGetIndex(this);
+}
+
+/// Set an entry on a native list.
+///
+/// [object] must be null or a native list, and [index] must be an integer.
+///
+/// The primitive itself has no value and may not be referenced.
+class SetIndex extends Primitive {
+  final Reference<Primitive> object;
+  final Reference<Primitive> index;
+  final Reference<Primitive> value;
+
+  SetIndex(Primitive object, Primitive index, Primitive value)
+      : this.object = new Reference<Primitive>(object),
+        this.index = new Reference<Primitive>(index),
+        this.value = new Reference<Primitive>(value);
+
+  bool get isSafeForElimination => false;
+  bool get isSafeForReordering => false;
+
+  accept(Visitor v) => v.visitSetIndex(this);
+}
+
 /// Reads the value of a static field or tears off a static method.
 ///
 /// Note that lazily initialized fields should be read using GetLazyStatic.
 class GetStatic extends Primitive {
   /// Can be [FieldElement] or [FunctionElement].
   final Element element;
   final SourceInformation sourceInformation;
 
   GetStatic(this.element, [this.sourceInformation]);
 
   accept(Visitor visitor) => visitor.visitGetStatic(this);
-  
+
   bool get isSafeForElimination {
     return true;
   }
   bool get isSafeForReordering {
     return element is FunctionElement || element.isFinal;
   }
 }
 
 /// Sets the value of a static field.
 class SetStatic extends Expression implements InteriorNode {
@@ skipping 359 matching lines @@
   T visitInterceptor(Interceptor node);
   T visitCreateInstance(CreateInstance node);
   T visitGetField(GetField node);
   T visitCreateBox(CreateBox node);
   T visitReifyRuntimeType(ReifyRuntimeType node);
   T visitReadTypeVariable(ReadTypeVariable node);
   T visitTypeExpression(TypeExpression node);
   T visitCreateInvocationMirror(CreateInvocationMirror node);
   T visitTypeTest(TypeTest node);
   T visitApplyBuiltinOperator(ApplyBuiltinOperator node);
+  T visitGetLength(GetLength node);
+  T visitGetIndex(GetIndex node);
+  T visitSetIndex(SetIndex node);
 
   // Conditions.
   T visitIsTrue(IsTrue node);
 
   // Support for literal foreign code.
   T visitForeignCode(ForeignCode node);
 }
 
 /// Recursively visits the entire CPS term, and calls abstract `process*`
 /// (i.e. `processLetPrim`) functions in pre-order.
@@ skipping 270 matching lines @@
     if (node.continuation != null) {
       processReference(node.continuation);
     }
     node.arguments.forEach(processReference);
   }
 
   processUnreachable(Unreachable node) {}
   visitUnreachable(Unreachable node) {
     processUnreachable(node);
   }
+
+  processGetLength(GetLength node) {}
+  visitGetLength(GetLength node) {
+    processGetLength(node);
+    processReference(node.object);
+  }
+
+  processGetIndex(GetIndex node) {}
+  visitGetIndex(GetIndex node) {
+    processGetIndex(node);
+    processReference(node.object);
+    processReference(node.index);
+  }
+
+  processSetIndex(SetIndex node) {}
+  visitSetIndex(SetIndex node) {
+    processSetIndex(node);
+    processReference(node.object);
+    processReference(node.index);
+    processReference(node.value);
+  }
 }
 
 /// Visit a just-deleted subterm and unlink all [Reference]s in it.
 class RemovalVisitor extends RecursiveVisitor {
   const RemovalVisitor();
 
   processReference(Reference reference) {
     reference.unlink();
   }
 
   static void remove(Node node) {
     (const RemovalVisitor()).visit(node);
   }
 }