Improve memory usage of receiver type feedback.

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index fccf1aa1cc2f4b235afb3a0836390805bbe65818..f31fa1d0def171d5e844f35438528d98a87466b2 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -33,6 +33,7 @@
 #include "factory.h"
 #include "jsregexp.h"
 #include "runtime.h"
+#include "small-pointer-list.h"
 #include "token.h"
 #include "variables.h"
 
@@ -207,6 +208,35 @@ class Statement: public AstNode {
 };
 
 
+class SmallMapList {
+ public:
+  SmallMapList() {}
+  explicit SmallMapList(int capacity) : list_(capacity) {}
+
+  void Reserve(int capacty) { list_.Reserve(capacty); }

[fschneider, 2011/08/22 13:38:06]

capacty -> capacity

+  void Clear() { list_.Clear(); }
+
+  bool is_empty() const { return list_.is_empty(); }
+  int length() const { return list_.length(); }
+
+  void Add(Handle<Map> handle) {
+    list_.Add(handle.location());
+  }
+
+  Handle<Map> at(int i) const {
+    return Handle<Map>(list_.at(i));
+  }
+
+  Handle<Map> first() const { return at(0); }
+  Handle<Map> last() const { return at(length() - 1); }
+
+ private:
+  SmallPointerList<Map*> list_;
+
+  DISALLOW_COPY_AND_ASSIGN(SmallMapList);
+};
+
+
 class Expression: public AstNode {
  public:
   enum Context {
@@ -265,13 +295,15 @@ class Expression: public AstNode {
     UNREACHABLE();
     return false;
   }
-  virtual ZoneMapList* GetReceiverTypes() {
+  virtual SmallMapList* GetReceiverTypes() {
     UNREACHABLE();
     return NULL;
   }
-  virtual Handle<Map> GetMonomorphicReceiverType() {
-    UNREACHABLE();
-    return Handle<Map>();
+  Handle<Map> GetMonomorphicReceiverType() {
+    ASSERT(IsMonomorphic());
+    SmallMapList* types = GetReceiverTypes();
+    ASSERT(types != NULL && types->length() == 1);
+    return types->at(0);
   }
 
   unsigned id() const { return id_; }
@@ -1211,7 +1243,6 @@ class Property: public Expression {
         key_(key),
         pos_(pos),
         type_(type),
-        receiver_types_(NULL),
         is_monomorphic_(false),
         is_array_length_(false),
         is_string_length_(false),
@@ -1235,11 +1266,8 @@ class Property: public Expression {
   // Type feedback information.
   void RecordTypeFeedback(TypeFeedbackOracle* oracle);
   virtual bool IsMonomorphic() { return is_monomorphic_; }
-  virtual ZoneMapList* GetReceiverTypes() { return receiver_types_; }
+  virtual SmallMapList* GetReceiverTypes() { return &receiver_types_; }
   virtual bool IsArrayLength() { return is_array_length_; }
-  virtual Handle<Map> GetMonomorphicReceiverType() {
-    return monomorphic_receiver_type_;
-  }
 
  private:
   Expression* obj_;
@@ -1247,13 +1275,12 @@ class Property: public Expression {
   int pos_;
   Type type_;
 
-  ZoneMapList* receiver_types_;
+  SmallMapList receiver_types_;
   bool is_monomorphic_ : 1;
   bool is_array_length_ : 1;
   bool is_string_length_ : 1;
   bool is_string_access_ : 1;
   bool is_function_prototype_ : 1;
-  Handle<Map> monomorphic_receiver_type_;
 };
 
 
@@ -1269,7 +1296,6 @@ class Call: public Expression {
         pos_(pos),
         is_monomorphic_(false),
         check_type_(RECEIVER_MAP_CHECK),
-        receiver_types_(NULL),
         return_id_(GetNextId(isolate)) {
   }
 
@@ -1283,7 +1309,7 @@ class Call: public Expression {
 
   void RecordTypeFeedback(TypeFeedbackOracle* oracle,
                           CallKind call_kind);
-  virtual ZoneMapList* GetReceiverTypes() { return receiver_types_; }
+  virtual SmallMapList* GetReceiverTypes() { return &receiver_types_; }
   virtual bool IsMonomorphic() { return is_monomorphic_; }
   CheckType check_type() const { return check_type_; }
   Handle<JSFunction> target() { return target_; }
@@ -1308,7 +1334,7 @@ class Call: public Expression {
 
   bool is_monomorphic_;
   CheckType check_type_;
-  ZoneMapList* receiver_types_;
+  SmallMapList receiver_types_;
   Handle<JSFunction> target_;
   Handle<JSObject> holder_;
   Handle<JSGlobalPropertyCell> cell_;
@@ -1483,8 +1509,7 @@ class CountOperation: public Expression {
         expression_(expr),
         pos_(pos),
         assignment_id_(GetNextId(isolate)),
-        count_id_(GetNextId(isolate)),
-        receiver_types_(NULL) { }
+        count_id_(GetNextId(isolate)) {}
 
   DECLARE_NODE_TYPE(CountOperation)
 
@@ -1505,10 +1530,7 @@ class CountOperation: public Expression {
 
   void RecordTypeFeedback(TypeFeedbackOracle* oracle);
   virtual bool IsMonomorphic() { return is_monomorphic_; }
-  virtual Handle<Map> GetMonomorphicReceiverType() {
-    return monomorphic_receiver_type_;
-  }
-  virtual ZoneMapList* GetReceiverTypes() { return receiver_types_; }
+  virtual SmallMapList* GetReceiverTypes() { return &receiver_types_; }
 
   // Bailout support.
   int AssignmentId() const { return assignment_id_; }
@@ -1522,8 +1544,7 @@ class CountOperation: public Expression {
   int pos_;
   int assignment_id_;
   int count_id_;
-  Handle<Map> monomorphic_receiver_type_;
-  ZoneMapList* receiver_types_;
+  SmallMapList receiver_types_;
 };
 
 
@@ -1671,10 +1692,7 @@ class Assignment: public Expression {
   // Type feedback information.
   void RecordTypeFeedback(TypeFeedbackOracle* oracle);
   virtual bool IsMonomorphic() { return is_monomorphic_; }
-  virtual ZoneMapList* GetReceiverTypes() { return receiver_types_; }
-  virtual Handle<Map> GetMonomorphicReceiverType() {
-    return monomorphic_receiver_type_;
-  }
+  virtual SmallMapList* GetReceiverTypes() { return &receiver_types_; }
 
   // Bailout support.
   int CompoundLoadId() const { return compound_load_id_; }
@@ -1693,8 +1711,7 @@ class Assignment: public Expression {
   bool block_end_;
 
   bool is_monomorphic_;
-  ZoneMapList* receiver_types_;
-  Handle<Map> monomorphic_receiver_type_;
+  SmallMapList receiver_types_;
 };