Stop resolving all of js_helper unconditionally.

sdk/lib/_internal/compiler/implementation/ssa/codegen.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 ssa;
 
 class SsaCodeGeneratorTask extends CompilerTask {
 
   final JavaScriptBackend backend;
 
@@ skipping 2098 matching lines @@
     if (!node.isConstantString()) return false;
     HConstant constant = node;
     StringConstant string = constant.constant;
     return string.value.length == 0;
   }
 
   void useStringified(HInstruction node) {
     if (node.isString(types)) {
       use(node);
     } else {
-      Element convertToString = compiler.findHelper(const SourceString("S"));
+      Element convertToString = backend.getStringInterpolationHelper();
       world.registerStaticUse(convertToString);
       js.VariableUse variableUse =
           new js.VariableUse(backend.namer.isolateAccess(convertToString));
       use(node);
       push(new js.Call(variableUse, <js.Expression>[pop()]), node);
     }
   }
 
   void visitLiteralList(HLiteralList node) {
     world.registerInstantiatedClass(compiler.listClass);
@@ skipping 256 matching lines @@
       attachLocationToLast(node);
     }
     if (node.nullOk) {
       checkNull(input);
       push(new js.Binary('||', pop(), pop()), node);
     }
   }
 
   // TODO(johnniwinther): Refactor this method.
   void visitTypeConversion(HTypeConversion node) {
-    Map<String, SourceString> castNames = const <String, SourceString> {
-      "stringTypeCheck":
-          const SourceString("stringTypeCast"),
-      "doubleTypeCheck":
-          const SourceString("doubleTypeCast"),
-      "numTypeCheck":
-          const SourceString("numTypeCast"),
-      "boolTypeCheck":
-          const SourceString("boolTypeCast"),
-      "functionTypeCheck":
-          const SourceString("functionTypeCast"),
-      "intTypeCheck":
-          const SourceString("intTypeCast"),
-      "numberOrStringSuperNativeTypeCheck":
-          const SourceString("numberOrStringSuperNativeTypeCast"),
-      "numberOrStringSuperTypeCheck":
-          const SourceString("numberOrStringSuperTypeCast"),
-      "stringSuperNativeTypeCheck":
-          const SourceString("stringSuperNativeTypeCast"),
-      "stringSuperTypeCheck":
-          const SourceString("stringSuperTypeCast"),
-      "listTypeCheck":
-          const SourceString("listTypeCast"),
-      "listSuperNativeTypeCheck":
-          const SourceString("listSuperNativeTypeCast"),
-      "listSuperTypeCheck":
-          const SourceString("listSuperTypeCast"),
-      "callTypeCheck":
-          const SourceString("callTypeCast"),
-      "propertyTypeCheck":
-          const SourceString("propertyTypeCast"),
-      // TODO(johnniwinther): Add a malformedTypeCast which produces a TypeError
-      // with another message.
-      "malformedTypeCheck":
-          const SourceString("malformedTypeCheck")
-    };
-
     if (node.isChecked) {
       DartType type = node.type.computeType(compiler);
       Element element = type.element;
       world.registerIsCheck(type);
 
       if (node.isArgumentTypeCheck) {
         if (element == backend.jsIntClass) {
           checkInt(node.checkedInput, '!==');
         } else {
           assert(element == backend.jsNumberClass);
@@ skipping 10 matching lines @@
         return;
       }
       assert(node.isCheckedModeCheck || node.isCastTypeCheck);
 
       SourceString helper;
       if (node.isBooleanConversionCheck) {
         helper = const SourceString('boolConversionCheck');
       } else {
         helper = backend.getCheckedModeHelper(type);
         if (node.isCastTypeCheck) {
-          helper = castNames[helper.stringValue];
+          helper = backend.castNames[helper.stringValue];
         }
       }
       FunctionElement helperElement = compiler.findHelper(helper);
       world.registerStaticUse(helperElement);
       List<js.Expression> arguments = <js.Expression>[];
       use(node.checkedInput);
       arguments.add(pop());
       int parameterCount =
           helperElement.computeSignature(compiler).parameterCount;
       if (parameterCount == 2) {
@@ skipping 539 matching lines @@
   if (leftType.canBeNull() && rightType.canBeNull()) {
     if (left.isConstantNull() || right.isConstantNull() ||
         (leftType.isPrimitive() && leftType == rightType)) {
       return '==';
     }
     return null;
   } else {
     return '===';
   }
 }