Add StaticUse for more precise registration of statically known element use.

pkg/compiler/lib/src/js_backend/checked_mode_helpers.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.
 
 part of js_backend;
 
 class CheckedModeHelper {
   final String name;
 
   const CheckedModeHelper(String this.name);
 
-  Element getElement(Compiler compiler) {
+  StaticUse getStaticUse(Compiler compiler) {
     JavaScriptBackend backend = compiler.backend;
-    return backend.helpers.findHelper(name);
+    return new StaticUse.staticInvoke(
+        backend.helpers.findHelper(name), callStructure);
   }
 
+  CallStructure get callStructure => CallStructure.ONE_ARG;
+
   jsAst.Expression generateCall(SsaCodeGenerator codegen,
                                 HTypeConversion node) {
-    Element helperElement = getElement(codegen.compiler);
-    codegen.registry.registerStaticUse(helperElement);
+    StaticUse staticUse = getStaticUse(codegen.compiler);
+    codegen.registry.registerStaticUse(staticUse);
     List<jsAst.Expression> arguments = <jsAst.Expression>[];
     codegen.use(node.checkedInput);
     arguments.add(codegen.pop());
     generateAdditionalArguments(codegen, node, arguments);
     jsAst.Expression helper =
-        codegen.backend.emitter.staticFunctionAccess(helperElement);
+        codegen.backend.emitter.staticFunctionAccess(staticUse.element);
     return new jsAst.Call(helper, arguments);
   }
 
   void generateAdditionalArguments(SsaCodeGenerator codegen,
                                    HTypeConversion node,
                                    List<jsAst.Expression> arguments) {
     // No additional arguments needed.
   }
 
   static const List<CheckedModeHelper> helpers = const <CheckedModeHelper> [
@@ skipping 29 matching lines @@
       const SubtypeCheckedModeHelper('assertSubtype'),
       const TypeVariableCheckedModeHelper('subtypeOfRuntimeTypeCast'),
       const TypeVariableCheckedModeHelper('assertSubtypeOfRuntimeType'),
       const PropertyCheckedModeHelper('propertyTypeCast'),
       const PropertyCheckedModeHelper('propertyTypeCheck')];
 }
 
 class MalformedCheckedModeHelper extends CheckedModeHelper {
   const MalformedCheckedModeHelper(String name) : super(name);
 
+  CallStructure get callStructure => CallStructure.TWO_ARGS;
+
   void generateAdditionalArguments(SsaCodeGenerator codegen,
                                    HTypeConversion node,
                                    List<jsAst.Expression> arguments) {
     ErroneousElement element = node.typeExpression.element;
     arguments.add(js.escapedString(element.message));
   }
 }
 
 class PropertyCheckedModeHelper extends CheckedModeHelper {
   const PropertyCheckedModeHelper(String name) : super(name);
 
+  CallStructure get callStructure => CallStructure.TWO_ARGS;
+
   void generateAdditionalArguments(SsaCodeGenerator codegen,
                                    HTypeConversion node,
                                    List<jsAst.Expression> arguments) {
     DartType type = node.typeExpression;
     jsAst.Name additionalArgument = codegen.backend.namer.operatorIsType(type);
     arguments.add(js.quoteName(additionalArgument));
   }
 }
 
 class TypeVariableCheckedModeHelper extends CheckedModeHelper {
   const TypeVariableCheckedModeHelper(String name) : super(name);
 
+  CallStructure get callStructure => CallStructure.TWO_ARGS;
+
   void generateAdditionalArguments(SsaCodeGenerator codegen,
                                    HTypeConversion node,
                                    List<jsAst.Expression> arguments) {
     assert(node.typeExpression.isTypeVariable);
     codegen.use(node.typeRepresentation);
     arguments.add(codegen.pop());
   }
 }
 
 class SubtypeCheckedModeHelper extends CheckedModeHelper {
   const SubtypeCheckedModeHelper(String name) : super(name);
 
+  CallStructure get callStructure => const CallStructure.unnamed(4);
+
   void generateAdditionalArguments(SsaCodeGenerator codegen,
                                    HTypeConversion node,
                                    List<jsAst.Expression> arguments) {
     DartType type = node.typeExpression;
     Element element = type.element;
     jsAst.Name isField = codegen.backend.namer.operatorIs(element);
     arguments.add(js.quoteName(isField));
     codegen.use(node.typeRepresentation);
     arguments.add(codegen.pop());
     jsAst.Name asField = codegen.backend.namer.substitutionName(element);
     arguments.add(js.quoteName(asField));
   }
 }