Fix bad mangling of environment parameters.

lib/compiler/implementation/ssa/variable_allocator.dart

 // Copyright (c) 2012, 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.
 
 /**
  * The [LiveRange] class covers a range where an instruction is live.
  */
 class LiveRange {
   final int start;
   // [end] is not final because it can be updated due to loops.
@@ skipping 414 matching lines @@
 class VariableNamer {
   final VariableNames names;
   final Set<String> usedNames;
   final Map<Element, String> parameterNames;
   final List<String> freeTemporaryNames;
   int temporaryIndex = 0;
 
   VariableNamer(LiveEnvironment environment, this.names, this.parameterNames)
     : usedNames = new Set<String>(),
       freeTemporaryNames = new List<String>() {
-    // [VariableNames.swapTemp] and [VariableNames.stateName] are being used
-    // throughout the function. Therefore we make sure no one uses it at any
-    // time.
+    // [VariableNames.swapTemp] is used when there is a cycle in a copy handler.
+    // Therefore we make sure no one uses it.
     usedNames.add(names.swapTemp);
+    // [VariableNames.stateName] is being used throughout a bailout function.
+    // Whenever a bailout-target is reached we set the state-variable to 0. We
+    // must therefore not have any local variable that could clash with the
+    // state variable.
+    // Therefore we make sure no one uses it at any time.
     usedNames.add(names.stateName);
 
     // All liveIns instructions must have a name at this point, so we
     // add them to the list of used names.
     environment.liveInstructions.forEach((HInstruction instruction, int index) {
       String name = names.getName(instruction);
       if (name != null) {
         usedNames.add(name);
       }
     });
@@ skipping 201 matching lines @@
       if (!needsName(input)) {
         names.addAssignment(predecessor, input, phi);
       } else {
         names.addCopy(predecessor, input, phi);
       }
     }
 
     namer.allocateName(phi);
   }
 }