Better tracking of provided types at call sites

lib/compiler/implementation/ssa/builder.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.
 
 class Interceptors {
   Compiler compiler;
   Interceptors(Compiler this.compiler);
 
   SourceString mapOperatorToMethodName(Operator op) {
     String name = op.source.stringValue;
@@ skipping 160 matching lines @@
       assert(graph.isValid());
       bool inLoop = functionsCalledInLoop.contains(element);
       if (!inLoop) {
         Selector selector = selectorsCalledInLoop[element.name];
         inLoop = selector !== null && selector.applies(element, compiler);
       }
       graph.calledInLoop = inLoop;
 
       // If there is an estimate of the parameter types assume these types when
       // compiling.
+      OptionalParameterTypes defaultValueTypes = null;
+      FunctionSignature signature = element.computeSignature(compiler);
+      if (signature.optionalParameterCount > 0) {
+        defaultValueTypes =
+            new OptionalParameterTypes(signature.optionalParameterCount);
+        int index = 0;
+        signature.forEachOptionalParameter((Element parameter) {
+          Constant defaultValue = compiler.compileVariable(parameter);
+          HType type = HGraph.mapConstantTypeToSsaType(defaultValue);
+          defaultValueTypes.insert(index, parameter.name, type);
+          index++;
+        });
+      }
       HTypeList parameterTypes =
-          backend.optimisticParameterTypes(
-              element);
+          backend.optimisticParameterTypes(element, defaultValueTypes);
       if (!parameterTypes.allUnknown) {
-        FunctionSignature signature = element.computeSignature(compiler);
         int i = 0;
         signature.forEachParameter((Element param) {
           builder.parameters[param].guaranteedType = parameterTypes[i++];
         });
       }
-      backend.registerParameterTypesOptimization(element, parameterTypes);
+      backend.registerParameterTypesOptimization(
+          element, parameterTypes, defaultValueTypes);
 
       if (compiler.tracer.enabled) {
         String name;
         if (element.isMember()) {
           String className = element.getEnclosingClass().name.slowToString();
           String memberName = element.name.slowToString();
           name = "$className.$memberName";
           if (element.kind == ElementKind.GENERATIVE_CONSTRUCTOR_BODY) {
             name = "$name (body)";
           }
@@ skipping 3731 matching lines @@
           new HSubGraphBlockInformation(elseBranch.graph));
 
     HBasicBlock conditionStartBlock = conditionBranch.block;
     conditionStartBlock.setBlockFlow(info, joinBlock);
     SubGraph conditionGraph = conditionBranch.graph;
     HIf branch = conditionGraph.end.last;
     assert(branch is HIf);
     branch.blockInformation = conditionStartBlock.blockFlow;
   }
 }