Fix bug when a variable is used in try/catch and accessed trough HFieldGet and HFieldSet: reference…

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
===================================================================
--- lib/compiler/implementation/ssa/builder.dart	(revision 7983)
+++ lib/compiler/implementation/ssa/builder.dart	(working copy)
@@ -412,7 +412,8 @@
       return lookup;
     } else {
       assert(isUsedInTry(element));
-      HInstruction variable = new HFieldGet.fromActivation(element.name);
+      HParameterValue parameter = getActivationParameter(element);
+      HInstruction variable = new HFieldGet.fromActivation(parameter);
       builder.add(variable);
       return variable;
     }
@@ -435,6 +436,16 @@
     return res;
   }
 
+  HParameterValue getActivationParameter(Element element) {
+    if (element.isParameter()) return directLocals[element];
+
+    return builder.activationVariables.putIfAbsent(element, () {
+      HParameterValue parameter = new HParameterValue(element);
+      builder.add(parameter);
+      return parameter;
+    });
+  }
+
   /**
    * Sets the [element] to [value]. If the element is boxed or stored in a
    * closure then the method generates code to set the value.
@@ -461,7 +472,8 @@
       builder.add(new HFieldSet(redirect.name, box, value));
     } else {
       assert(isUsedInTry(element));
-      builder.add(new HFieldSet.fromActivation(element.name, value));
+      HParameterValue parameter = getActivationParameter(element);
+      builder.add(new HFieldSet.fromActivation(parameter, value));
     }
   }
 
@@ -779,6 +791,13 @@
 
   Map<TargetElement, JumpHandler> jumpTargets;
 
+  /**
+   * Variables stored in the current activation. These variables are
+   * being updated in try/catch blocks, and should be
+   * accessed indirectly through HFieldGet and HFieldSet.
+   */
+  Map<Element, HParameterValue> activationVariables;
+
   // We build the Ssa graph by simulating a stack machine.
   List<HInstruction> stack;
 
@@ -802,6 +821,7 @@
       elements = work.resolutionTree,
       graph = new HGraph(),
       stack = new List<HInstruction>(),
+      activationVariables = new Map<Element, HParameterValue>(),
       jumpTargets = new Map<TargetElement, JumpHandler>() {
     localsHandler = new LocalsHandler(this);
   }