Validate that all instructions dominate their inputs. And fix a bug where that did not happen.

lib/compiler/implementation/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 visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
   R visitBitXor(HBitXor node);
@@ skipping 643 matching lines @@
   }
 
   void forEachPhi(void f(HPhi phi)) {
     HPhi current = phis.first;
     while (current !== null) {
       f(current);
       current = current.next;
     }
   }
 
+  void forEachInstruction(void f(HInstruction instruction)) {
+    HInstruction current = first;
+    while (current !== null) {

[Lasse Reichstein Nielsen, 2012/05/30 09:35:14]

A block must have a non-null first instruction (right?).
So you could make this a do-while instead and save one comparison :)

[ngeoffray, 2012/05/30 10:19:07]

It might be safer to keep it as-is in case one use forEachInstruction while
building (and the block does not have any instruction).

+      f(current);
+      current = current.next;
+    }
+  }
+
   bool isValid() {
     assert(isClosed());
     HValidator validator = new HValidator();
     validator.visitBasicBlock(this);
     return validator.isValid;
   }
 
   // TODO(ngeoffray): Cache the information if this method ends up
   // being hot.
   bool dominates(HBasicBlock other) {
@@ skipping 983 matching lines @@
   final TargetElement target;
   final LabelElement label;
   HContinue(this.target) : label = null;
   HContinue.toLabel(LabelElement label) : label = label, target = label.target;
   toString() => (label !== null) ? 'continue ${label.labelName}' : 'continue';
   accept(HVisitor visitor) => visitor.visitContinue(this);
 }
 
 class HTry extends HControlFlow {
   HParameterValue exception;
+  HBasicBlock catchBlock;
   HBasicBlock finallyBlock;
   HTry() : super(const <HInstruction>[]);
   toString() => 'try';
   accept(HVisitor visitor) => visitor.visitTry(this);
   HBasicBlock get joinBlock() => this.block.successors.last();
 }
 
 class HIf extends HConditionalBranch {
   bool hasElse;
   HBlockFlow blockInformation = null;
@@ skipping 793 matching lines @@
                        this.catchBlock,
                        this.finallyBlock);
 
   HBasicBlock get start() => body.start;
   HBasicBlock get end() =>
       finallyBlock === null ? catchBlock.end : finallyBlock.end;
 
   bool accept(HStatementInformationVisitor visitor) =>
     visitor.visitTryInfo(this);
 }