Revert "Revert "Reland 21774: Generate KeyedLoadGeneric with Hydrogen""

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 "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/builtins.h"
@@ skipping 6705 matching lines @@
   static const int kInObjectPropertiesByte = 1;
   static const int kInObjectPropertiesOffset =
       kInstanceSizesOffset + kInObjectPropertiesByte;
   static const int kPreAllocatedPropertyFieldsByte = 2;
   static const int kPreAllocatedPropertyFieldsOffset =
       kInstanceSizesOffset + kPreAllocatedPropertyFieldsByte;
   static const int kVisitorIdByte = 3;
   static const int kVisitorIdOffset = kInstanceSizesOffset + kVisitorIdByte;
 
   // Byte offsets within kInstanceAttributesOffset attributes.
+#if V8_TARGET_LITTLE_ENDIAN
+  // Order instance type and bit field together such that they can be loaded
+  // together as a 16-bit word with instance type in the lower 8 bits regardless
+  // of endianess.
   static const int kInstanceTypeOffset = kInstanceAttributesOffset + 0;
-  static const int kUnusedPropertyFieldsOffset = kInstanceAttributesOffset + 1;
-  static const int kBitFieldOffset = kInstanceAttributesOffset + 2;
-  static const int kBitField2Offset = kInstanceAttributesOffset + 3;
+  static const int kBitFieldOffset = kInstanceAttributesOffset + 1;
+#else
+  static const int kBitFieldOffset = kInstanceAttributesOffset + 0;
+  static const int kInstanceTypeOffset = kInstanceAttributesOffset + 1;
+#endif
+  static const int kBitField2Offset = kInstanceAttributesOffset + 2;
+  static const int kUnusedPropertyFieldsOffset = kInstanceAttributesOffset + 3;
 
   STATIC_ASSERT(kInstanceTypeOffset == Internals::kMapInstanceTypeOffset);

[mtbrandy, 2014/06/17 13:45:40]

This change introduces a mismatch between kInstanceTypeOffset and
Internals::kMapInstanceTypeOffset on big endian platforms.

 
   // Bit positions for bit field.
   static const int kHasNonInstancePrototype = 0;
   static const int kIsHiddenPrototype = 1;
   static const int kHasNamedInterceptor = 2;
   static const int kHasIndexedInterceptor = 3;
   static const int kIsUndetectable = 4;
   static const int kIsObserved = 5;
   static const int kIsAccessCheckNeeded = 6;
   class FunctionWithPrototype: public BitField<bool, 7,  1> {};
@@ skipping 2299 matching lines @@
 // Ecma-262:
 //  4.3.16 String Value
 //    A string value is a member of the type String and is a finite
 //    ordered sequence of zero or more 16-bit unsigned integer values.
 //
 // All string values have a length field.
 class String: public Name {
  public:
   enum Encoding { ONE_BYTE_ENCODING, TWO_BYTE_ENCODING };
 
+  // Array index strings this short can keep their index in the hash field.
+  static const int kMaxCachedArrayIndexLength = 7;
+
+  // For strings which are array indexes the hash value has the string length
+  // mixed into the hash, mainly to avoid a hash value of zero which would be
+  // the case for the string '0'. 24 bits are used for the array index value.
+  static const int kArrayIndexValueBits = 24;
+  static const int kArrayIndexLengthBits =
+      kBitsPerInt - kArrayIndexValueBits - kNofHashBitFields;
+
+  STATIC_ASSERT((kArrayIndexLengthBits > 0));
+
+  class ArrayIndexValueBits : public BitField<unsigned int, kNofHashBitFields,
+      kArrayIndexValueBits> {};  // NOLINT
+  class ArrayIndexLengthBits : public BitField<unsigned int,
+      kNofHashBitFields + kArrayIndexValueBits,
+      kArrayIndexLengthBits> {};  // NOLINT
+
+  // Check that kMaxCachedArrayIndexLength + 1 is a power of two so we
+  // could use a mask to test if the length of string is less than or equal to
+  // kMaxCachedArrayIndexLength.
+  STATIC_ASSERT(IS_POWER_OF_TWO(kMaxCachedArrayIndexLength + 1));
+
+  static const unsigned int kContainsCachedArrayIndexMask =
+      (~kMaxCachedArrayIndexLength << ArrayIndexLengthBits::kShift) |
+      kIsNotArrayIndexMask;
+
   // Representation of the flat content of a String.
   // A non-flat string doesn't have flat content.
   // A flat string has content that's encoded as a sequence of either
   // ASCII chars or two-byte UC16.
   // Returned by String::GetFlatContent().
   class FlatContent {
    public:
     // Returns true if the string is flat and this structure contains content.
     bool IsFlat() { return state_ != NON_FLAT; }
     // Returns true if the structure contains ASCII content.
@@ skipping 2173 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_