Refactoring of string literals. Implement static string addition.

frog/leg/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.
 
 class SsaOptimizerTask extends CompilerTask {
   SsaOptimizerTask(Compiler compiler) : super(compiler);
   String get name() => 'SSA optimizer';
 
   void optimize(WorkItem work, HGraph graph) {
     measure(() {
@@ skipping 85 matching lines @@
       => node.fold();
 
   HInstruction visitAdd(HAdd node) {
     // String + is defined for all literals. We don't need to know which
     // literal type the right-hand side is.
 
     if (node.left.isString()) {
       // First try to eliminate adding the empty string to a string.
       if (node.right.isLiteralString()) {
         HLiteral right = node.right;
-        QuotedString rightString = right.value;
+        DartString rightString = right.value;
         if (rightString.isEmpty()) {
           // String has no content, i.e., it's the empty string.
           return node.left;
         }
       }
       // Then, if both are literals, try to do the concatenation statically.
       if (node.left.isLiteralString()) {
         HLiteral left = node.left;
-        QuotedString leftString = left.value;
+        DartString leftString = left.value;
         if (leftString.isEmpty()) {
           // Left is empty String.
           if (node.right.isString()) {
             // Right is already a String, just return that.
             return node.right;
           }
           if (node.right is HLiteral) {
             HLiteral right = node.right;
             // Right is a literal, so we can statically convert it to String
             // and return that.
             // Remaining literal types are represented by their Dart value.
             assert(right.isLiteralBoolean() ||
                    right.isLiteralNumber() ||
                    right.isLiteralNull());
             String str;
             // Workaround Frog bug. Issue #595.
             if (right.isLiteralNull()) {
               str = 'null';
             } else {
               str = right.value.toString();
             }
-            return new HLiteral(new QuotedString.literal(str), HType.STRING);
+            return new HLiteral(new DartString.literal(str), HType.STRING);
           }
         }
         // TODO(lrn): Perform concatenation in Dart.
       }
     }
     return visitInvokeBinary(node);
   }
 
   HInstruction visitEquals(HEquals node) {
     if (node.left is HLiteral && node.right is HLiteral) {
@@ skipping 457 matching lines @@
         }
       }
       if (!canBeMoved) continue;
 
       // This is safe because we are running after GVN.
       // TODO(ngeoffray): ensure GVN has been run.
       set_.add(current);
     }
   }
 }