Store pointer instead of reference to LocalVariable in ast and flow graph.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
===================================================================
--- runtime/vm/intermediate_language.h	(revision 10207)
+++ runtime/vm/intermediate_language.h	(working copy)
@@ -759,13 +759,15 @@
 
 class LoadLocalComp : public TemplateComputation<0> {
  public:
-  LoadLocalComp(const LocalVariable& local, intptr_t context_level)
+  LoadLocalComp(const LocalVariable* local, intptr_t context_level)
       : local_(local),
-        context_level_(context_level) { }
+        context_level_(context_level) {
+    ASSERT(local_ != NULL);
+  }
 
   DECLARE_COMPUTATION(LoadLocal)
 
-  const LocalVariable& local() const { return local_; }
+  const LocalVariable* local() const { return local_; }
   intptr_t context_level() const { return context_level_; }
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
@@ -773,7 +775,7 @@
   virtual bool CanDeoptimize() const { return false; }
 
  private:
-  const LocalVariable& local_;
+  const LocalVariable* local_;
   const intptr_t context_level_;
 
   DISALLOW_COPY_AND_ASSIGN(LoadLocalComp);
@@ -782,17 +784,18 @@
 
 class StoreLocalComp : public TemplateComputation<1> {
  public:
-  StoreLocalComp(const LocalVariable& local,
+  StoreLocalComp(const LocalVariable* local,
                  Value* value,
                  intptr_t context_level)
       : local_(local),
         context_level_(context_level) {
+    ASSERT(local_ != NULL);
     inputs_[0] = value;
   }
 
   DECLARE_COMPUTATION(StoreLocal)
 
-  const LocalVariable& local() const { return local_; }
+  const LocalVariable* local() const { return local_; }
   Value* value() const { return inputs_[0]; }
   intptr_t context_level() const { return context_level_; }
 
@@ -804,7 +807,7 @@
   virtual bool CanDeoptimize() const { return false; }
 
  private:
-  const LocalVariable& local_;
+  const LocalVariable* local_;
   const intptr_t context_level_;
 
   DISALLOW_COPY_AND_ASSIGN(StoreLocalComp);
@@ -1565,12 +1568,15 @@
 
 class CatchEntryComp : public TemplateComputation<0> {
  public:
-  CatchEntryComp(const LocalVariable& exception_var,
-                 const LocalVariable& stacktrace_var)
-      : exception_var_(exception_var), stacktrace_var_(stacktrace_var) {}
+  CatchEntryComp(const LocalVariable* exception_var,
+                 const LocalVariable* stacktrace_var)
+      : exception_var_(exception_var), stacktrace_var_(stacktrace_var) {
+    ASSERT(exception_var_ != NULL);
+    ASSERT(stacktrace_var_ != NULL);
+  }
 
-  const LocalVariable& exception_var() const { return exception_var_; }
-  const LocalVariable& stacktrace_var() const { return stacktrace_var_; }
+  const LocalVariable* exception_var() const { return exception_var_; }
+  const LocalVariable* stacktrace_var() const { return stacktrace_var_; }
 
   DECLARE_COMPUTATION(CatchEntry)
 
@@ -1579,8 +1585,8 @@
   virtual bool CanDeoptimize() const { return false; }
 
  private:
-  const LocalVariable& exception_var_;
-  const LocalVariable& stacktrace_var_;
+  const LocalVariable* exception_var_;
+  const LocalVariable* stacktrace_var_;
 
   DISALLOW_COPY_AND_ASSIGN(CatchEntryComp);
 };