Recognize unmodifiable lists

pkg/compiler/lib/src/js_backend/backend.dart

 // Copyright (c) 2012, 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.
 
 part of js_backend;
 
 const VERBOSE_OPTIMIZER_HINTS = false;
 
 class JavaScriptItemCompilationContext extends ItemCompilationContext {
   final Set<HInstruction> boundsChecked = new Set<HInstruction>();
@@ skipping 272 matching lines @@
   ClassElement jsBoolClass;
   ClassElement jsPlainJavaScriptObjectClass;
   ClassElement jsUnknownJavaScriptObjectClass;
 
   ClassElement jsIndexableClass;
   ClassElement jsMutableIndexableClass;
 
   ClassElement jsMutableArrayClass;
   ClassElement jsFixedArrayClass;
   ClassElement jsExtendableArrayClass;
+  ClassElement jsUnmodifiableArrayClass;
   ClassElement jsPositiveIntClass;
   ClassElement jsUInt32Class;
   ClassElement jsUInt31Class;
 
   Element jsIndexableLength;
   Element jsArrayTypedConstructor;
   Element jsArrayRemoveLast;
   Element jsArrayAdd;
   Element jsStringSplit;
   Element jsStringToString;
@@ skipping 76 matching lines @@
 
   TypeMask _extendableArrayTypeCache;
   TypeMask get extendableArrayType {
     if (_extendableArrayTypeCache == null) {
       _extendableArrayTypeCache =
           new TypeMask.nonNullExact(jsExtendableArrayClass, compiler.world);
     }
     return _extendableArrayTypeCache;
   }
 
+  TypeMask _unmodifiableArrayTypeCache;
+  TypeMask get unmodifiableArrayType {
+    if (_unmodifiableArrayTypeCache == null) {
+      _unmodifiableArrayTypeCache =
+          new TypeMask.nonNullExact(jsUnmodifiableArrayClass, compiler.world);
+    }
+    return _fixedArrayTypeCache;
+  }
+
   TypeMask _nonNullTypeCache;
   TypeMask get nonNullType {
     if (_nonNullTypeCache == null) {
       _nonNullTypeCache =
           compiler.typesTask.dynamicType.nonNullable();
     }
     return _nonNullTypeCache;
   }
 
   /// Maps special classes to their implementation (JSXxx) class.
@@ skipping 649 matching lines @@
     }
     if (cls == closureClass) {
       enqueue(enqueuer, findHelper('closureFromTearOff'), registry);
     }
     ClassElement result = null;
     if (cls == compiler.stringClass || cls == jsStringClass) {
       addInterceptors(jsStringClass, enqueuer, registry);
     } else if (cls == compiler.listClass ||
                cls == jsArrayClass ||
                cls == jsFixedArrayClass ||
-               cls == jsExtendableArrayClass) {
+               cls == jsExtendableArrayClass ||
+               cls == jsUnmodifiableArrayClass) {
       addInterceptors(jsArrayClass, enqueuer, registry);
       addInterceptors(jsMutableArrayClass, enqueuer, registry);
       addInterceptors(jsFixedArrayClass, enqueuer, registry);
       addInterceptors(jsExtendableArrayClass, enqueuer, registry);
+      addInterceptors(jsUnmodifiableArrayClass, enqueuer, registry);
     } else if (cls == compiler.intClass || cls == jsIntClass) {
       addInterceptors(jsIntClass, enqueuer, registry);
       addInterceptors(jsPositiveIntClass, enqueuer, registry);
       addInterceptors(jsUInt32Class, enqueuer, registry);
       addInterceptors(jsUInt31Class, enqueuer, registry);
       addInterceptors(jsNumberClass, enqueuer, registry);
     } else if (cls == compiler.doubleClass || cls == jsDoubleClass) {
       addInterceptors(jsDoubleClass, enqueuer, registry);
       addInterceptors(jsNumberClass, enqueuer, registry);
     } else if (cls == compiler.boolClass || cls == jsBoolClass) {
@@ skipping 559 matching lines @@
   bool hasDirectCheckFor(DartType type) {
     Element element = type.element;
     return element == compiler.stringClass ||
         element == compiler.boolClass ||
         element == compiler.numClass ||
         element == compiler.intClass ||
         element == compiler.doubleClass ||
         element == jsArrayClass ||
         element == jsMutableArrayClass ||
         element == jsExtendableArrayClass ||
-        element == jsFixedArrayClass;
+        element == jsFixedArrayClass ||
+        element == jsUnmodifiableArrayClass;
   }
 
   /// Return [true] if the class is represented by a native JavaSCript type in
   /// the generated code.
   bool isNativePrimitiveType(ClassElement cls ) {
     // TODO(karlklose): cleanup/merge with hasDirectCheck, when the rest of the
     // checks are implemented in the CPS IR.
     return cls == compiler.intClass ||
         cls == compiler.numClass ||
         cls == compiler.doubleClass ||
@@ skipping 211 matching lines @@
   }
 
   ClassElement get intImplementation => jsIntClass;
   ClassElement get uint32Implementation => jsUInt32Class;
   ClassElement get uint31Implementation => jsUInt31Class;
   ClassElement get positiveIntImplementation => jsPositiveIntClass;
   ClassElement get doubleImplementation => jsDoubleClass;
   ClassElement get numImplementation => jsNumberClass;
   ClassElement get stringImplementation => jsStringClass;
   ClassElement get listImplementation => jsArrayClass;
-  ClassElement get constListImplementation => jsArrayClass;
+  ClassElement get constListImplementation => jsUnmodifiableArrayClass;
   ClassElement get fixedListImplementation => jsFixedArrayClass;
   ClassElement get growableListImplementation => jsExtendableArrayClass;
   ClassElement get mapImplementation => mapLiteralClass;
   ClassElement get constMapImplementation => constMapLiteralClass;
   ClassElement get typeImplementation => typeLiteralClass;
   ClassElement get boolImplementation => jsBoolClass;
   ClassElement get nullImplementation => jsNullClass;
 
   void registerStaticUse(Element element, Enqueuer enqueuer) {
     if (element == disableTreeShakingMarker) {
@@ skipping 140 matching lines @@
           jsPositiveIntClass = findClass('JSPositiveInt'),
           jsUInt32Class = findClass('JSUInt32'),
           jsUInt31Class = findClass('JSUInt31'),
           jsDoubleClass = findClass('JSDouble'),
           jsNumberClass = findClass('JSNumber'),
           jsNullClass = findClass('JSNull'),
           jsBoolClass = findClass('JSBool'),
           jsMutableArrayClass = findClass('JSMutableArray'),
           jsFixedArrayClass = findClass('JSFixedArray'),
           jsExtendableArrayClass = findClass('JSExtendableArray'),
+          jsUnmodifiableArrayClass = findClass('JSUnmodifiableArray'),
           jsPlainJavaScriptObjectClass = findClass('PlainJavaScriptObject'),
           jsUnknownJavaScriptObjectClass = findClass('UnknownJavaScriptObject'),
         ];
 
         jsIndexableClass = findClass('JSIndexable');
         jsMutableIndexableClass = findClass('JSMutableIndexable');
       } else if (uri == DART_JS_HELPER) {
         initializeHelperClasses();
         assertMethod = findHelper('assertHelper');
 
@@ skipping 63 matching lines @@
 
     // TODO(kasperl): Some tests do not define the special JSArray
     // subclasses, so we check to see if they are defined before
     // trying to resolve them.
     if (jsFixedArrayClass != null) {
       jsFixedArrayClass.ensureResolved(compiler);
     }
     if (jsExtendableArrayClass != null) {
       jsExtendableArrayClass.ensureResolved(compiler);
     }
+    if (jsUnmodifiableArrayClass != null) {
+      jsUnmodifiableArrayClass.ensureResolved(compiler);
+    }
 
     jsIndexableClass.ensureResolved(compiler);
     jsIndexableLength = compiler.lookupElementIn(
         jsIndexableClass, 'length');
     if (jsIndexableLength != null && jsIndexableLength.isAbstractField) {
       AbstractFieldElement element = jsIndexableLength;
       jsIndexableLength = element.getter;
     }
 
     jsArrayClass.ensureResolved(compiler);
@@ skipping 796 matching lines @@
   }
 }
 
 /// Records that [constant] is used by the element behind [registry].
 class Dependency {
   final ConstantValue constant;
   final Element annotatedElement;
 
   const Dependency(this.constant, this.annotatedElement);
 }