Implement tracking and optimizations of packed arrays

src/elements.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 10 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_ELEMENTS_H_
 #define V8_ELEMENTS_H_
 
+#include "elements-kind.h"
 #include "objects.h"
 #include "heap.h"
 #include "isolate.h"
 
 namespace v8 {
 namespace internal {
 
 // Abstract base class for handles that can operate on objects with differing
 // ElementsKinds.
 class ElementsAccessor {
  public:
   explicit ElementsAccessor(const char* name) : name_(name) { }
   virtual ~ElementsAccessor() { }
 
   virtual ElementsKind kind() const = 0;
   const char* name() const { return name_; }
 
+  // Checks the elements of an object for consistency, asserting when a problem
+  // is found.
+  virtual void Validate(JSObject* obj) = 0;
+
   // Returns true if a holder contains an element with the specified key
   // without iterating up the prototype chain.  The caller can optionally pass
   // in the backing store to use for the check, which must be compatible with
   // the ElementsKind of the ElementsAccessor. If backing_store is NULL, the
   // holder->elements() is used as the backing store.
   virtual bool HasElement(Object* receiver,
                           JSObject* holder,
                           uint32_t key,
                           FixedArrayBase* backing_store = NULL) = 0;
 
@@ skipping 14 matching lines @@
   // element that is non-deletable.
   virtual MaybeObject* SetLength(JSArray* holder,
                                  Object* new_length) = 0;
 
   // Modifies both the length and capacity of a JSArray, resizing the underlying
   // backing store as necessary. This method does NOT honor the semantics of
   // EcmaScript 5.1 15.4.5.2, arrays can be shrunk beyond non-deletable
   // elements. This method should only be called for array expansion OR by
   // runtime JavaScript code that use InternalArrays and don't care about
   // EcmaScript 5.1 semantics.
-  virtual MaybeObject* SetCapacityAndLength(JSArray* array,
-                                            int capacity,
-                                            int length) = 0;
+  virtual MaybeObject* SetCapacityAndLength(

[Jakob Kummerow, 2012/05/13 21:55:27]

nit: why this formatting change?

[danno, 2012/05/22 11:05:21]

Done.

+      JSArray* array,
+      int capacity,
+      int length) = 0;
 
   // Deletes an element in an object, returning a new elements backing store.
   virtual MaybeObject* Delete(JSObject* holder,
                               uint32_t key,
                               JSReceiver::DeleteMode mode) = 0;
 
   // If kCopyToEnd is specified as the copy_size to CopyElements, it copies all
   // of elements from source after source_start to the destination array.
   static const int kCopyToEnd = -1;
   // If kCopyToEndAndInitializeToHole is specified as the copy_size to
@@ skipping 67 matching lines @@
                                 uint32_t from_start,
                                 FixedArray* to_obj,
                                 ElementsKind to_kind,
                                 uint32_t to_start,
                                 int copy_size);
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ELEMENTS_H_