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Unified Diff: src/objects.h

Issue 57123002: Reland 21774: Generate KeyedLoadGeneric with Hydrogen (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Fix GC Mole Created 6 years, 6 months ago
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Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 2ed61579ab0d4820da15db836edc7259e0bc2c72..c1ba60e972ab35b3c6b72e783a04cf91d099e8c3 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -6723,10 +6723,18 @@ class Map: public HeapObject {
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);
@@ -9048,6 +9056,33 @@ 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
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