Throw and a small fix to If.

frog/leg/ssa/validate.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 HValidator extends HInstructionVisitor {
   bool isValid = true;
   HGraph graph;
 
   void visitGraph(HGraph graph) {
     this.graph = graph;
     visitDominatorTree(graph);
   }
 
   void markInvalid(String reason) {
     print(reason);
     isValid = false;
   }
 
   // Note that during construction of the Ssa graph the basic blocks are
   // not required to be valid yet.
   void visitBasicBlock(HBasicBlock block) {
     if (!isValid) return;  // Don't need to continue if we are already invalid.
 
     // Test that the last instruction is a branching instruction and that the
     // basic block contains the branch-target.
     if (block.first === null || block.last === null) {
       markInvalid("empty block");
     }
-    if (block.last is !HIf &&
-        block.last is !HGoto &&
-        block.last is !HReturn &&
-        block.last is !HExit) {
+    if (block.last is !HControlFlow) {
       markInvalid("block ends with non-tail node.");
     }
     if (block.last is HIf && block.successors.length != 2) {
       markInvalid("If node without two successors");
     }
     if (block.last is HGoto && block.successors.length != 1) {
       markInvalid("Goto node without one successor");
     }
     if (block.last is HReturn &&
         (block.successors.length != 1 || !block.successors[0].isExitBlock())) {
       markInvalid("Return node with > 1 succesor or not going to exit-block");
     }
     if (block.last is HExit && !block.successors.isEmpty()) {
       markInvalid("Exit block with successor");
     }
+    if (block.last is HThrow && !block.successors.isEmpty()) {
+      markInvalid("Throw block with successor");
+    }
 
-    if (block.successors.isEmpty() && !block.isExitBlock()) {
-      markInvalid("Non-exit block without successor");
+    if (block.successors.isEmpty() &&
+        block.last is !HThrow &&
+        !block.isExitBlock()) {
+      markInvalid("Non-exit or throw block without successor");
     }
 
     // Make sure that successors ids are always higher than the current one.
     // TODO(floitsch): this is, of course, not true for back-branches.
     if (block.id === null) markInvalid("block without id");
     for (HBasicBlock successor in block.successors) {
       if (!isValid) break;
       if (successor.id === null) markInvalid("successor without id");
       if (successor.id <= block.id) {
         markInvalid("successor with lower id");
@@ skipping 69 matching lines @@
       if (!instruction.isInBasicBlock()) return true;
       return everyInstruction(instruction.usedBy, (use, count) {
         return countInstruction(use.inputs, instruction) == count;
       });
     }
 
     isValid = isValid &&
               hasCorrectInputs(instruction) && hasCorrectUses(instruction);
   }
 }