Fix wrong optimization for private fields

lib/compiler/implementation/ssa/optimize.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.
 
 interface OptimizationPhase {
   String get name();
   void visitGraph(HGraph graph);
 }
 
 class SsaOptimizerTask extends CompilerTask {
@@ skipping 545 matching lines @@
   }
 
   HInstruction visitInvokeDynamicGetter(HInvokeDynamicGetter node) {
     HInstruction receiver = node.inputs[0];
     if (!receiver.propagatedType.isUseful()) return node;
     if (receiver.propagatedType.canBeNull()) return node;
     Type type = receiver.propagatedType.computeType(compiler);
     if (type === null) return node;
     Element field = compiler.world.locateSingleField(type, node.name);
     if (field === null) return node;
+    if (field.getLibrary() !== work.element.getLibrary()) return node;

[floitsch, 2012/08/15 11:59:42]

why not looking if the field is private?
There should be something like node.name.isPrivate.

[Søren Gjesse, 2012/08/15 12:50:04]

It works if the check is just !node.name.isPrivate(). However that regresses
some benchmarks as it hits broadly.

But thanks to noticing, as the check should still include the
node.name.isPrivate(), as the library check should only be done for private
fields.

[floitsch, 2012/08/15 12:56:34]

That's what I meant.

     Modifiers modifiers = field.modifiers;
     bool isFinalOrConst = false;
     if (modifiers != null) {
       isFinalOrConst = modifiers.isFinal() || modifiers.isConst();
     }
     if (!compiler.resolverWorld.hasInvokedSetter(field, compiler)) {
       // If no setter is ever used for this field it is only initialized in the
       // initializer list.
       isFinalOrConst = true;
     }
@@ skipping 730 matching lines @@
       // this type for the field is still a strong signal
       // indicating the expected type of the field.
       field.propagatedType = type;
     } else {
       // If there are no invoked setters we know the type of
       // this field for sure.
       field.guaranteedType = type;
     }
   }
 }