Prototype re-compiling methods in dart2js

lib/compiler/implementation/ssa/optimize.dart

 // Copyright (c) 2011, 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 {
   final JavaScriptBackend backend;
   SsaOptimizerTask(JavaScriptBackend backend)
     : this.backend = backend,
       super(backend.compiler);
   String get name() => 'SSA optimizer';
   Compiler get compiler() => backend.compiler;
 
   void runPhases(HGraph graph, List<OptimizationPhase> phases) {
     for (OptimizationPhase phase in phases) {
       phase.visitGraph(graph);
       compiler.tracer.traceGraph(phase.name, graph);
     }
   }
 
   void optimize(WorkItem work, HGraph graph) {
     measure(() {
       List<OptimizationPhase> phases = <OptimizationPhase>[
           // Run trivial constant folding first to optimize
           // some patterns useful for type conversion.
-          new SsaConstantFolder(backend),
+          new SsaConstantFolder(backend, work),
           new SsaTypeConversionInserter(compiler),
           new SsaTypePropagator(compiler),
           new SsaCheckInserter(backend),
-          new SsaConstantFolder(backend),
+          new SsaConstantFolder(backend, work),
           new SsaRedundantPhiEliminator(),
           new SsaDeadPhiEliminator(),
           new SsaGlobalValueNumberer(compiler),
           new SsaCodeMotion(),
           new SsaDeadCodeEliminator()];
       runPhases(graph, phases);
     });
   }
 
   bool trySpeculativeOptimizations(WorkItem work, HGraph graph) {
@@ skipping 38 matching lines @@
   }
 }
 
 /**
  * If both inputs to known operations are available execute the operation at
  * compile-time.
  */
 class SsaConstantFolder extends HBaseVisitor implements OptimizationPhase {
   final String name = "SsaConstantFolder";
   final JavaScriptBackend backend;
+  final WorkItem work;
   HGraph graph;
   Compiler get compiler() => backend.compiler;
 
-  SsaConstantFolder(this.backend);
+  SsaConstantFolder(this.backend, this.work);
 
   void visitGraph(HGraph visitee) {
     graph = visitee;
     visitDominatorTree(visitee);
   }
 
   visitBasicBlock(HBasicBlock block) {
     HInstruction instruction = block.first;
     while (instruction !== null) {
       HInstruction next = instruction.next;
@@ skipping 464 matching lines @@
     if (!receiver.propagatedType.isUseful()) 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;
     Modifiers modifiers = field.modifiers;
     bool isFinalOrConst = false;
     if (modifiers != null) {
       isFinalOrConst = modifiers.isFinal() || modifiers.isConst();
     }
+    // If field is not final or const but no setters are used then the field
+    // might be considered final anyway as it will be either un-initialized
+    // or initialized in the constructor initializer list.
+    if (!isFinalOrConst && !compiler.world.isSetterUsed(type, node.name)) {
+      switch (compiler.pass) {
+        case 1:
+          compiler.enqueuer.codegen.addToWorkList2(work.element);
+          break;
+        case 2:
+          isFinalOrConst = true;
+          break;
+      }
+    }
     return new HFieldGet(field, node.inputs[0], isFinalOrConst: isFinalOrConst);
   }
 
   HInstruction visitInvokeDynamicSetter(HInvokeDynamicSetter node) {
     HInstruction receiver = node.inputs[0];
     if (!receiver.propagatedType.isUseful()) return node;
     Type type = receiver.propagatedType.computeType(compiler);
     if (type === null) return node;
+    compiler.world.setterUsed(type, node.name);
     Element field = compiler.world.locateSingleField(type, node.name);
     if (field === null) return node;
     return new HFieldSet(field, node.inputs[0], node.inputs[1]);
   }
 
   HInstruction visitStringConcat(HStringConcat node) {
     DartString folded = const LiteralDartString("");
     for (int i = 0; i < node.inputs.length; i++) {
       HInstruction part = node.inputs[i];
       if (!part.isConstant()) return node;
@@ skipping 538 matching lines @@
         // the if block terminates. So any use of the instruction
         // after the join block should be changed to the new
         // instruction.
         changeUsesDominatedBy(ifUser.joinBlock, input, convertedType);
       }
       // TODO(ngeoffray): Also change uses for the then block on a HType
       // that knows it is not of a specific Type.
     }
   }
 }