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

runtime/vm/ast.h

Index: runtime/vm/ast.h
===================================================================
--- runtime/vm/ast.h	(revision 10207)
+++ runtime/vm/ast.h	(working copy)
@@ -99,7 +99,7 @@
         id_(GetNextId()),
         ic_data_(ICData::ZoneHandle()),
         info_(NULL) {
-    ASSERT(token_pos >= 0);
+    ASSERT(token_pos_ >= 0);
   }
 
   intptr_t token_pos() const { return token_pos_; }
@@ -469,7 +469,7 @@
   ReturnNode(intptr_t token_pos,
              AstNode* value)
       : AstNode(token_pos), value_(value), inlined_finally_list_() {
-    ASSERT(value != NULL);
+    ASSERT(value_ != NULL);
   }
 
   AstNode* value() const { return value_; }
@@ -928,20 +928,20 @@
 
 class LoadLocalNode : public AstNode {
  public:
-  LoadLocalNode(intptr_t token_pos, const LocalVariable& local)
+  LoadLocalNode(intptr_t token_pos, const LocalVariable* local)
       : AstNode(token_pos), local_(local), pseudo_(NULL) {
-    ASSERT(&local_ != NULL);
+    ASSERT(local_ != NULL);

[Ivan Posva, 2012/08/03 20:10:26]

local_ = *local;

[regis, 2012/08/06 22:31:49]

This is actually not possible, because of
DISALLOW_COPY_AND_ASSIGN(LocalVariable).

I can either remove this restriction, or assign via the initializer, but this
would not prevent dereferencing of NULL:


  LoadLocalNode(intptr_t token_pos, const LocalVariable* local)
      : AstNode(token_pos), local_(*local), pseudo_(NULL) {
    ASSERT(local != NULL);
  }

   }
   // The pseudo node does not produce input but must be visited before
   // completing local load.
   LoadLocalNode(intptr_t token_pos,
-                const LocalVariable& local,
+                const LocalVariable* local,
                 AstNode* pseudo)
       : AstNode(token_pos), local_(local), pseudo_(pseudo) {
-    ASSERT(&local_ != NULL);
+    ASSERT(local_ != NULL);
   }
 
-  const LocalVariable& local() const { return local_; }
+  const LocalVariable* local() const { return local_; }

[Ivan Posva, 2012/08/03 20:10:26]

Then this change is not needed, which is causing you a massive amount of changes
to follow.

[regis, 2012/08/06 22:31:49]

Done.

   AstNode* pseudo() const { return pseudo_; }  // Can be NULL.
   bool HasPseudo() const { return pseudo_ != NULL; }
 
@@ -956,7 +956,7 @@
   DECLARE_COMMON_NODE_FUNCTIONS(LoadLocalNode);
 
  private:
-  const LocalVariable& local_;
+  const LocalVariable* local_;

[Ivan Posva, 2012/08/03 20:10:26]

ditto.

[regis, 2012/08/06 22:31:49]

Done.

   AstNode* pseudo_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(LoadLocalNode);
@@ -966,14 +966,14 @@
 class StoreLocalNode : public AstNode {
  public:
   StoreLocalNode(intptr_t token_pos,
-                 const LocalVariable& local,
+                 const LocalVariable* local,
                  AstNode* value)
       : AstNode(token_pos), local_(local), value_(value) {
-    ASSERT(&local_ != NULL);
+    ASSERT(local_ != NULL);
     ASSERT(value_ != NULL);
   }
 
-  const LocalVariable& local() const { return local_; }
+  const LocalVariable* local() const { return local_; }
   AstNode* value() const { return value_; }
 
   virtual void VisitChildren(AstNodeVisitor* visitor) const {
@@ -983,7 +983,7 @@
   DECLARE_COMMON_NODE_FUNCTIONS(StoreLocalNode);
 
  private:
-  const LocalVariable& local_;
+  const LocalVariable* local_;
   AstNode* value_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(StoreLocalNode);
@@ -1109,8 +1109,8 @@
  public:
   LoadIndexedNode(intptr_t token_pos, AstNode* array, AstNode* index)
       : AstNode(token_pos), array_(array), index_expr_(index) {
-    ASSERT(array != NULL);
-    ASSERT(index != NULL);
+    ASSERT(array_ != NULL);
+    ASSERT(index_expr_ != NULL);
   }
 
   AstNode* array() const { return array_; }
@@ -1137,9 +1137,9 @@
   StoreIndexedNode(intptr_t token_pos,
                    AstNode* array, AstNode* index, AstNode* value)
     : AstNode(token_pos), array_(array), index_expr_(index), value_(value) {
-    ASSERT(array != NULL);
-    ASSERT(index != NULL);
-    ASSERT(value != NULL);
+    ASSERT(array_ != NULL);
+    ASSERT(index_expr_ != NULL);
+    ASSERT(value_ != NULL);
   }
 
   AstNode* array() const { return array_; }
@@ -1317,7 +1317,7 @@
         value_(value) {
     ASSERT(cls_.IsZoneHandle());
     ASSERT(field_name_.IsZoneHandle());
-    ASSERT(value != NULL);
+    ASSERT(value_ != NULL);
   }
 
   const Class& cls() const { return cls_; }
@@ -1433,7 +1433,7 @@
                       const AbstractTypeArguments& type_arguments,
                       const Function& constructor,
                       ArgumentListNode* arguments,
-                      const LocalVariable& allocated_object_var)
+                      const LocalVariable* allocated_object_var)
       : AstNode(token_pos),
         type_arguments_(type_arguments),
         constructor_(constructor),
@@ -1442,6 +1442,7 @@
     ASSERT(type_arguments_.IsZoneHandle());
     ASSERT(constructor_.IsZoneHandle());
     ASSERT(arguments_ != NULL);
+    ASSERT(allocated_object_var_ != NULL);
   }
 
   const AbstractTypeArguments& type_arguments() const {
@@ -1449,7 +1450,7 @@
   }
   const Function& constructor() const { return constructor_; }
   ArgumentListNode* arguments() const { return arguments_; }
-  const LocalVariable& allocated_object_var() const {
+  const LocalVariable* allocated_object_var() const {
     return allocated_object_var_;
   }
 
@@ -1463,7 +1464,7 @@
   const AbstractTypeArguments& type_arguments_;
   const Function& constructor_;
   ArgumentListNode* arguments_;
-  const LocalVariable& allocated_object_var_;
+  const LocalVariable* allocated_object_var_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(ConstructorCallNode);
 };
@@ -1522,16 +1523,19 @@
 
   CatchClauseNode(intptr_t token_pos,
                   SequenceNode* catch_block,
-                  const LocalVariable& context_var,
-                  const LocalVariable& exception_var,
-                  const LocalVariable& stacktrace_var)
+                  const LocalVariable* context_var,
+                  const LocalVariable* exception_var,
+                  const LocalVariable* stacktrace_var)
       : AstNode(token_pos),
         try_index_(kInvalidTryIndex),
         catch_block_(catch_block),
         context_var_(context_var),
         exception_var_(exception_var),
         stacktrace_var_(stacktrace_var) {
-    ASSERT(catch_block != NULL);
+    ASSERT(catch_block_ != NULL);
+    ASSERT(context_var_ != NULL);
+    ASSERT(exception_var_ != NULL);
+    ASSERT(stacktrace_var_ != NULL);
   }
 
   int try_index() const {
@@ -1540,9 +1544,9 @@
   }
   void set_try_index(int value) { try_index_ = value; }
 
-  const LocalVariable& context_var() const { return context_var_; }
-  const LocalVariable& exception_var() const { return exception_var_; }
-  const LocalVariable& stacktrace_var() const { return stacktrace_var_; }
+  const LocalVariable* context_var() const { return context_var_; }
+  const LocalVariable* exception_var() const { return exception_var_; }
+  const LocalVariable* stacktrace_var() const { return stacktrace_var_; }
 
   virtual void VisitChildren(AstNodeVisitor* visitor) const {
     catch_block_->Visit(visitor);
@@ -1553,9 +1557,9 @@
  private:
   int try_index_;  // Running index of the try blocks seen in a function.
   SequenceNode* catch_block_;
-  const LocalVariable& context_var_;
-  const LocalVariable& exception_var_;
-  const LocalVariable& stacktrace_var_;
+  const LocalVariable* context_var_;
+  const LocalVariable* exception_var_;
+  const LocalVariable* stacktrace_var_;
 
   DISALLOW_COPY_AND_ASSIGN(CatchClauseNode);
 };
@@ -1566,7 +1570,7 @@
   TryCatchNode(intptr_t token_pos,
                SequenceNode* try_block,
                SourceLabel* end_catch_label,
-               const LocalVariable& context_var,
+               const LocalVariable* context_var,
                CatchClauseNode* catch_block,
                SequenceNode* finally_block)
       : AstNode(token_pos),
@@ -1575,16 +1579,17 @@
         context_var_(context_var),
         catch_block_(catch_block),
         finally_block_(finally_block) {
-    ASSERT(try_block != NULL);
-    ASSERT(catch_block != NULL || finally_block != NULL);
-    ASSERT(end_catch_label != NULL);
+    ASSERT(try_block_ != NULL);
+    ASSERT(context_var_ != NULL);
+    ASSERT(catch_block_ != NULL || finally_block_ != NULL);
+    ASSERT(end_catch_label_ != NULL);
   }
 
   SequenceNode* try_block() const { return try_block_; }
   SourceLabel* end_catch_label() const { return end_catch_label_; }
   CatchClauseNode* catch_block() const { return catch_block_; }
   SequenceNode* finally_block() const { return finally_block_; }
-  const LocalVariable& context_var() const { return context_var_; }
+  const LocalVariable* context_var() const { return context_var_; }
 
   virtual void VisitChildren(AstNodeVisitor* visitor) const {
     try_block_->Visit(visitor);
@@ -1601,7 +1606,7 @@
  private:
   SequenceNode* try_block_;
   SourceLabel* end_catch_label_;
-  const LocalVariable& context_var_;
+  const LocalVariable* context_var_;
   CatchClauseNode* catch_block_;
   SequenceNode* finally_block_;
 
@@ -1613,7 +1618,7 @@
  public:
   ThrowNode(intptr_t token_pos, AstNode* exception, AstNode* stacktrace)
       : AstNode(token_pos), exception_(exception), stacktrace_(stacktrace) {
-    ASSERT(exception != NULL);
+    ASSERT(exception_ != NULL);
   }
 
   AstNode* exception() const { return exception_; }
@@ -1639,24 +1644,26 @@
  public:
   InlinedFinallyNode(intptr_t token_pos,
                      AstNode* finally_block,
-                     const LocalVariable& context_var)
+                     const LocalVariable* context_var)
       : AstNode(token_pos),
         finally_block_(finally_block),
         context_var_(context_var) {
-    ASSERT(finally_block != NULL);
+    ASSERT(finally_block_ != NULL);
+    ASSERT(context_var_ != NULL);
   }
 
   AstNode* finally_block() const { return finally_block_; }
-  const LocalVariable& context_var() const { return context_var_; }
+  const LocalVariable* context_var() const { return context_var_; }
 
   virtual void VisitChildren(AstNodeVisitor* visitor) const {
     finally_block()->Visit(visitor);
   }
 
   DECLARE_COMMON_NODE_FUNCTIONS(InlinedFinallyNode);
+

[Ivan Posva, 2012/08/03 20:10:26]

Why here, but not on line 1634?

[regis, 2012/08/06 22:31:49]

Added new line after 1634.

  private:
   AstNode* finally_block_;
-  const LocalVariable& context_var_;
+  const LocalVariable* context_var_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(InlinedFinallyNode);
 };