Make string juxtaposition combine properly with string interpolations.

frog/leg/ssa/nodes.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 HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBailoutTarget(HBailoutTarget node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
@@ skipping 1369 matching lines @@
     if (input == target) return HType.UNKNOWN;
     if (isString() || left.isString()) {
       return (input == left) ? HType.STRING : HType.UNKNOWN;
     }
     if (right.isString()) return HType.STRING;
     if (isNumber() || left.isNumber() || right.isNumber()) return HType.NUMBER;
     return HType.UNKNOWN;
   }
 
   AddOperation get operation() => const AddOperation();
+
+  HInstruction fold(HGraph graph) {

[ngeoffray, 2012/03/14 12:29:58]

Is that dead code? There is no fold method in the instructions anymore, and line
1409 would fail.

[Lasse Reichstein Nielsen, 2012/03/14 13:04:49]

It's probably dead, just leftover of a merge that didn't recognize it as gone.
I'll remove it and check.

+    // TODO(floitsch): move this code to the compile-time-constant handler.
+    if (left.isConstantString() && right is HConstant) {
+      HConstant op1 = left;
+      HConstant op2 = right;
+      DartString leftString = op1.constant.value;
+      DartString otherString = null;
+      if (right.isConstantString()) {
+        otherString = op2.constant.value;
+      } else {
+        assert(op2.isConstantNumber() ||
+               op2.isConstantBoolean() ||
+               op2.isConstantNull());
+        otherString = new DartString.literal(op2.constant.value.toString());
+      }
+      DartString cons = new DartString.concat(leftString, otherString);
+      return graph.addConstantString(cons);
+    }
+    return super.fold(graph);
+  }
+
   int typeCode() => 5;
   bool typeEquals(other) => other is HAdd;
   bool dataEquals(HInstruction other) => true;
 }
 
 class HDivide extends HBinaryArithmetic {
   HDivide(HStatic target, HInstruction left, HInstruction right)
       : super(target, left, right);
   accept(HVisitor visitor) => visitor.visitDivide(this);
 
@@ skipping 738 matching lines @@
 class HIfBlockInformation {
   final HIf branch;
   final SubGraph thenGraph;
   final SubGraph elseGraph;
   final HBasicBlock joinBlock;
   HIfBlockInformation(this.branch,
                       this.thenGraph,
                       this.elseGraph,
                       this.joinBlock);
 }