Implement tracking and optimizations of packed arrays

src/objects.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 12 matching lines @@
 // 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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include "allocation.h"
 #include "builtins.h"
+#include "elements-kind.h"
 #include "list.h"
 #include "property-details.h"
 #include "smart-array-pointer.h"
 #include "unicode-inl.h"
 #if V8_TARGET_ARCH_ARM
 #include "arm/constants-arm.h"
 #elif V8_TARGET_ARCH_MIPS
 #include "mips/constants-mips.h"
 #endif
 #include "v8checks.h"
@@ skipping 81 matching lines @@
 //         - CodeCache
 //
 // Formats of Object*:
 //  Smi:        [31 bit signed int] 0
 //  HeapObject: [32 bit direct pointer] (4 byte aligned) | 01
 //  Failure:    [30 bit signed int] 11
 
 namespace v8 {
 namespace internal {
 
-enum ElementsKind {
-  // The "fast" kind for elements that only contain SMI values. Must be first
-  // to make it possible to efficiently check maps for this kind.
-  FAST_SMI_ONLY_ELEMENTS,
-
-  // The "fast" kind for tagged values. Must be second to make it possible to
-  // efficiently check maps for this and the FAST_SMI_ONLY_ELEMENTS kind
-  // together at once.
-  FAST_ELEMENTS,
-
-  // The "fast" kind for unwrapped, non-tagged double values.
-  FAST_DOUBLE_ELEMENTS,
-
-  // The "slow" kind.
-  DICTIONARY_ELEMENTS,
-  NON_STRICT_ARGUMENTS_ELEMENTS,
-  // The "fast" kind for external arrays
-  EXTERNAL_BYTE_ELEMENTS,
-  EXTERNAL_UNSIGNED_BYTE_ELEMENTS,
-  EXTERNAL_SHORT_ELEMENTS,
-  EXTERNAL_UNSIGNED_SHORT_ELEMENTS,
-  EXTERNAL_INT_ELEMENTS,
-  EXTERNAL_UNSIGNED_INT_ELEMENTS,
-  EXTERNAL_FLOAT_ELEMENTS,
-  EXTERNAL_DOUBLE_ELEMENTS,
-  EXTERNAL_PIXEL_ELEMENTS,
-
-  // Derived constants from ElementsKind
-  FIRST_EXTERNAL_ARRAY_ELEMENTS_KIND = EXTERNAL_BYTE_ELEMENTS,
-  LAST_EXTERNAL_ARRAY_ELEMENTS_KIND = EXTERNAL_PIXEL_ELEMENTS,
-  FIRST_ELEMENTS_KIND = FAST_SMI_ONLY_ELEMENTS,
-  LAST_ELEMENTS_KIND = EXTERNAL_PIXEL_ELEMENTS
-};
-
 enum CompareMapMode {
   REQUIRE_EXACT_MAP,
   ALLOW_ELEMENT_TRANSITION_MAPS
 };
 
 enum KeyedAccessGrowMode {
   DO_NOT_ALLOW_JSARRAY_GROWTH,
   ALLOW_JSARRAY_GROWTH
 };
 
-const int kElementsKindCount = LAST_ELEMENTS_KIND - FIRST_ELEMENTS_KIND + 1;
-
-void PrintElementsKind(FILE* out, ElementsKind kind);
-
-inline bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind,
-                                                ElementsKind to_kind);
-
 // Setter that skips the write barrier if mode is SKIP_WRITE_BARRIER.
 enum WriteBarrierMode { SKIP_WRITE_BARRIER, UPDATE_WRITE_BARRIER };
 
 
 // PropertyNormalizationMode is used to specify whether to keep
 // inobject properties when normalizing properties of a JSObject.
 enum PropertyNormalizationMode {
   CLEAR_INOBJECT_PROPERTIES,
   KEEP_INOBJECT_PROPERTIES
 };
@@ skipping 1308 matching lines @@
   // EnsureWritableFastElements in this case.
   //
   // In the slow mode the elements is either a NumberDictionary, an
   // ExternalArray, or a FixedArray parameter map for a (non-strict)
   // arguments object.
   DECL_ACCESSORS(elements, FixedArrayBase)
   inline void initialize_elements();
   MUST_USE_RESULT inline MaybeObject* ResetElements();
   inline ElementsKind GetElementsKind();
   inline ElementsAccessor* GetElementsAccessor();
-  inline bool HasFastSmiOnlyElements();
-  inline bool HasFastElements();
-  // Returns if an object has either FAST_ELEMENT or FAST_SMI_ONLY_ELEMENT
-  // elements.  TODO(danno): Rename HasFastTypeElements to HasFastElements() and
-  // HasFastElements to HasFastObjectElements.
-  inline bool HasFastTypeElements();
+  // Returns true if an object has elements of FAST_SMI_ELEMENTS ElementsKind.
+  inline bool HasFastSmiElements();
+  // Returns true if an object has elements of FAST_ELEMENTS ElementsKind.
+  inline bool HasFastObjectElements();
+  // Returns true if an object has elements of FAST_ELEMENTS or
+  // FAST_SMI_ONLY_ELEMENTS.
+  inline bool HasFastSmiOrObjectElements();
+  // Returns true if an object has elements of FAST_DOUBLE_ELEMENTS
+  // ElementsKind.
   inline bool HasFastDoubleElements();
+  // Returns true if an object has elements of FAST_HOLEY_*_ELEMENTS
+  // ElementsKind.
+  inline bool HasFastHoleyElements();
   inline bool HasNonStrictArgumentsElements();
   inline bool HasDictionaryElements();
   inline bool HasExternalPixelElements();
   inline bool HasExternalArrayElements();
   inline bool HasExternalByteElements();
   inline bool HasExternalUnsignedByteElements();
   inline bool HasExternalShortElements();
   inline bool HasExternalUnsignedShortElements();
   inline bool HasExternalIntElements();
   inline bool HasExternalUnsignedIntElements();
@@ skipping 182 matching lines @@
   MUST_USE_RESULT MaybeObject* GetIdentityHash(CreationFlag flag);
   MUST_USE_RESULT MaybeObject* SetIdentityHash(Object* hash, CreationFlag flag);
 
   static Handle<Object> DeleteProperty(Handle<JSObject> obj,
                                        Handle<String> name);
   MUST_USE_RESULT MaybeObject* DeleteProperty(String* name, DeleteMode mode);
 
   static Handle<Object> DeleteElement(Handle<JSObject> obj, uint32_t index);
   MUST_USE_RESULT MaybeObject* DeleteElement(uint32_t index, DeleteMode mode);
 
-  inline void ValidateSmiOnlyElements();
+  inline void ValidateElements();
 
   // Makes sure that this object can contain HeapObject as elements.
   MUST_USE_RESULT inline MaybeObject* EnsureCanContainHeapObjectElements();
 
   // Makes sure that this object can contain the specified elements.
   MUST_USE_RESULT inline MaybeObject* EnsureCanContainElements(
       Object** elements,
       uint32_t count,
       EnsureElementsMode mode);
   MUST_USE_RESULT inline MaybeObject* EnsureCanContainElements(
       FixedArrayBase* elements,
+      uint32_t length,
       EnsureElementsMode mode);
   MUST_USE_RESULT MaybeObject* EnsureCanContainElements(
       Arguments* arguments,
       uint32_t first_arg,
       uint32_t arg_count,
       EnsureElementsMode mode);
 
   // Do we want to keep the elements in fast case when increasing the
   // capacity?
   bool ShouldConvertToSlowElements(int new_capacity);
@@ skipping 78 matching lines @@
       PropertyAttributes attributes,
       StrictModeFlag strict_mode,
       bool check_prototype = true,
       SetPropertyMode set_mode = SET_PROPERTY);
 
   // Returns the index'th element.
   // The undefined object if index is out of bounds.
   MUST_USE_RESULT MaybeObject* GetElementWithInterceptor(Object* receiver,
                                                          uint32_t index);
 
-  enum SetFastElementsCapacityMode {
-    kAllowSmiOnlyElements,
-    kForceSmiOnlyElements,
-    kDontAllowSmiOnlyElements
+  enum SetFastElementsCapacitySmiMode {
+    kAllowSmiElements,
+    kForceSmiElements,
+    kDontAllowSmiElements
   };
 
   // Replace the elements' backing store with fast elements of the given
   // capacity.  Update the length for JSArrays.  Returns the new backing
   // store.
   MUST_USE_RESULT MaybeObject* SetFastElementsCapacityAndLength(
       int capacity,
       int length,
-      SetFastElementsCapacityMode set_capacity_mode);
+      SetFastElementsCapacitySmiMode smi_mode);
   MUST_USE_RESULT MaybeObject* SetFastDoubleElementsCapacityAndLength(
       int capacity,
       int length);
 
   // Lookup interceptors are used for handling properties controlled by host
   // objects.
   inline bool HasNamedInterceptor();
   inline bool HasIndexedInterceptor();
 
   // Support functions for v8 api (needed for correct interceptor behavior).
@@ skipping 2785 matching lines @@
         (elements_kind << kElementsKindShift));
     ASSERT(this->elements_kind() == elements_kind);
   }
 
   inline ElementsKind elements_kind() {
     return static_cast<ElementsKind>(
         (bit_field2() & kElementsKindMask) >> kElementsKindShift);
   }
 
   // Tells whether the instance has fast elements that are only Smis.
-  inline bool has_fast_smi_only_elements() {
-    return elements_kind() == FAST_SMI_ONLY_ELEMENTS;
+  inline bool has_fast_smi_elements() {
+    return IsFastSmiElementsKind(elements_kind());
   }
 
   // Tells whether the instance has fast elements.
-  inline bool has_fast_elements() {
-    return elements_kind() == FAST_ELEMENTS;
+  inline bool has_fast_object_elements() {
+    return IsFastObjectElementsKind(elements_kind());
+  }
+
+  inline bool has_fast_smi_or_object_elements() {
+    return IsFastSmiOrObjectElementsKind(elements_kind());
   }
 
   inline bool has_fast_double_elements() {
-    return elements_kind() == FAST_DOUBLE_ELEMENTS;
+    return IsFastDoubleElementsKind(elements_kind());
   }
 
   inline bool has_non_strict_arguments_elements() {
     return elements_kind() == NON_STRICT_ARGUMENTS_ELEMENTS;
   }
 
   inline bool has_external_array_elements() {
     ElementsKind kind(elements_kind());
     return kind >= FIRST_EXTERNAL_ARRAY_ELEMENTS_KIND &&
         kind <= LAST_EXTERNAL_ARRAY_ELEMENTS_KIND;
@@ skipping 267 matching lines @@
   static const int kHasNonInstancePrototype = 1;
   static const int kIsHiddenPrototype = 2;
   static const int kHasNamedInterceptor = 3;
   static const int kHasIndexedInterceptor = 4;
   static const int kIsUndetectable = 5;
   static const int kHasInstanceCallHandler = 6;
   static const int kIsAccessCheckNeeded = 7;
 
   // Bit positions for bit field 2
   static const int kIsExtensible = 0;
-  static const int kFunctionWithPrototype = 1;
-  static const int kStringWrapperSafeForDefaultValueOf = 2;
-  static const int kAttachedToSharedFunctionInfo = 3;
+  static const int kStringWrapperSafeForDefaultValueOf = 1;
+  static const int kAttachedToSharedFunctionInfo = 2;
   // No bits can be used after kElementsKindFirstBit, they are all reserved for
   // storing ElementKind.
-  static const int kElementsKindShift = 4;
-  static const int kElementsKindBitCount = 4;
+  static const int kElementsKindShift = 3;
+  static const int kElementsKindBitCount = 5;
 
   // Derived values from bit field 2
   static const int kElementsKindMask = (-1 << kElementsKindShift) &
       ((1 << (kElementsKindShift + kElementsKindBitCount)) - 1);
   static const int8_t kMaximumBitField2FastElementValue = static_cast<int8_t>(
       (FAST_ELEMENTS + 1) << Map::kElementsKindShift) - 1;
-  static const int8_t kMaximumBitField2FastSmiOnlyElementValue =
-      static_cast<int8_t>((FAST_SMI_ONLY_ELEMENTS + 1) <<
+  static const int8_t kMaximumBitField2FastSmiElementValue =
+      static_cast<int8_t>((FAST_SMI_ELEMENTS + 1) <<
+                          Map::kElementsKindShift) - 1;
+  static const int8_t kMaximumBitField2FastHoleyElementValue =
+      static_cast<int8_t>((FAST_HOLEY_ELEMENTS + 1) <<
+                          Map::kElementsKindShift) - 1;
+  static const int8_t kMaximumBitField2FastHoleySmiElementValue =
+      static_cast<int8_t>((FAST_HOLEY_SMI_ELEMENTS + 1) <<
                           Map::kElementsKindShift) - 1;
 
   // Bit positions for bit field 3
   static const int kIsShared = 0;
+  static const int kFunctionWithPrototype = 1;
 
   // Layout of the default cache. It holds alternating name and code objects.
   static const int kCodeCacheEntrySize = 2;
   static const int kCodeCacheEntryNameOffset = 0;
   static const int kCodeCacheEntryCodeOffset = 1;
 
   typedef FixedBodyDescriptor<kPointerFieldsBeginOffset,
                               kPointerFieldsEndOffset,
                               kSize> BodyDescriptor;
 
@@ skipping 3683 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_