Retain maps embedded in optimized code for several garbage collections.

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 923 matching lines @@
   V(Map)                           \
   V(DescriptorArray)               \
   V(TransitionArray)               \
   V(TypeFeedbackVector)            \
   V(DeoptimizationInputData)       \
   V(DeoptimizationOutputData)      \
   V(DependentCode)                 \
   V(FixedArray)                    \
   V(FixedDoubleArray)              \
   V(WeakFixedArray)                \
+  V(ArrayList)                     \
   V(ConstantPoolArray)             \
   V(Context)                       \
   V(ScriptContextTable)            \
   V(NativeContext)                 \
   V(ScopeInfo)                     \
   V(JSFunction)                    \
   V(Code)                          \
   V(Oddball)                       \
   V(SharedFunctionInfo)            \
   V(JSValue)                       \
@@ skipping 1666 matching lines @@
   inline void set_last_used_index(int index);
 
   // Disallow inherited setters.
   void set(int index, Smi* value);
   void set(int index, Object* value);
   void set(int index, Object* value, WriteBarrierMode mode);
   DISALLOW_IMPLICIT_CONSTRUCTORS(WeakFixedArray);
 };
 
 
+// Generic array grows dynamically with O(1) amortized insertion.
+class ArrayList : public FixedArray {
+ public:
+  static Handle<ArrayList> Add(Handle<ArrayList> array, Handle<Object> obj);
+  static Handle<ArrayList> Add(Handle<ArrayList> array, Handle<Object> obj1,
+                               Handle<Object> obj2);
+  inline int Length();
+  inline void SetLength(int length);
+  inline Object* Get(int index);
+  inline Object** Slot(int index);
+  inline void Set(int index, Object* obj);
+  inline void Clear(int index, Object* undefined);
+  DECLARE_CAST(ArrayList)
+
+ private:
+  static Handle<ArrayList> EnsureSpace(Handle<ArrayList> array, int length);
+  static const int kLengthIndex = 0;
+  static const int kFirstIndex = 1;
+  DISALLOW_IMPLICIT_CONSTRUCTORS(ArrayList);
+};
+
+
 // ConstantPoolArray describes a fixed-sized array containing constant pool
 // entries.
 //
 // A ConstantPoolArray can be structured in two different ways depending upon
 // whether it is extended or small. The is_extended_layout() method can be used
 // to discover which layout the constant pool has.
 //
 // The format of a small constant pool is:
 //   [kSmallLayout1Offset]                    : Small section layout bitmap 1
 //   [kSmallLayout2Offset]                    : Small section layout bitmap 2
@@ skipping 8343 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_