src/objects.h - Issue 8677006: Recommit introducing short external strings.

Unified Diff: src/objects.h

Issue 8677006: Recommit introducing short external strings. (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge

Patch Set: Fixing webkit failures. Created 9 years, 1 month ago

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Index: src/objects.h

diff --git a/src/objects.h b/src/objects.h

index b376bcc30e2b7c9727f69d0481962ccdfe83ffbf..ed2b8b7514d50a77b53520393f46fff09a116f2e 100644

--- a/src/objects.h

+++ b/src/objects.h

@@ -232,6 +232,9 @@ static const int kVariableSizeSentinel = 0;

V(EXTERNAL_SYMBOL_TYPE) \

V(EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE) \

V(EXTERNAL_ASCII_SYMBOL_TYPE) \

+ V(SHORT_EXTERNAL_SYMBOL_TYPE) \

+ V(SHORT_EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE) \

+ V(SHORT_EXTERNAL_ASCII_SYMBOL_TYPE) \

V(STRING_TYPE) \

V(ASCII_STRING_TYPE) \

V(CONS_STRING_TYPE) \

@@ -240,6 +243,9 @@ static const int kVariableSizeSentinel = 0;

V(EXTERNAL_STRING_TYPE) \

V(EXTERNAL_STRING_WITH_ASCII_DATA_TYPE) \

V(EXTERNAL_ASCII_STRING_TYPE) \

+ V(SHORT_EXTERNAL_STRING_TYPE) \

+ V(SHORT_EXTERNAL_STRING_WITH_ASCII_DATA_TYPE) \

+ V(SHORT_EXTERNAL_ASCII_STRING_TYPE) \

V(PRIVATE_EXTERNAL_ASCII_STRING_TYPE) \

V(MAP_TYPE) \

@@ -340,6 +346,18 @@ static const int kVariableSizeSentinel = 0;

ExternalAsciiString::kSize, \

external_ascii_symbol, \

ExternalAsciiSymbol) \

+ V(SHORT_EXTERNAL_SYMBOL_TYPE, \

+ ExternalTwoByteString::kShortSize, \

+ short_external_symbol, \

+ ShortExternalSymbol) \

+ V(SHORT_EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE, \

+ ExternalTwoByteString::kShortSize, \

+ short_external_symbol_with_ascii_data, \

+ ShortExternalSymbolWithAsciiData) \

+ V(SHORT_EXTERNAL_ASCII_SYMBOL_TYPE, \

+ ExternalAsciiString::kShortSize, \

+ short_external_ascii_symbol, \

+ ShortExternalAsciiSymbol) \

V(STRING_TYPE, \

kVariableSizeSentinel, \

string, \

@@ -375,7 +393,19 @@ static const int kVariableSizeSentinel = 0;

V(EXTERNAL_ASCII_STRING_TYPE, \

ExternalAsciiString::kSize, \

external_ascii_string, \

- ExternalAsciiString)

+ ExternalAsciiString) \

+ V(SHORT_EXTERNAL_STRING_TYPE, \

+ ExternalTwoByteString::kShortSize, \

+ short_external_string, \

+ ShortExternalString) \

+ V(SHORT_EXTERNAL_STRING_WITH_ASCII_DATA_TYPE, \

+ ExternalTwoByteString::kShortSize, \

+ short_external_string_with_ascii_data, \

+ ShortExternalStringWithAsciiData) \

+ V(SHORT_EXTERNAL_ASCII_STRING_TYPE, \

+ ExternalAsciiString::kShortSize, \

+ short_external_ascii_string, \

+ ShortExternalAsciiString)

// A struct is a simple object a set of object-valued fields. Including an

// object type in this causes the compiler to generate most of the boilerplate

@@ -459,6 +489,11 @@ STATIC_ASSERT(IS_POWER_OF_TWO(kSlicedNotConsMask) && kSlicedNotConsMask != 0);

const uint32_t kAsciiDataHintMask = 0x08;

const uint32_t kAsciiDataHintTag = 0x08;

+// If bit 7 is clear and string representation indicates an external string,

+// then bit 4 indicates whether the data pointer is cached.

+const uint32_t kShortExternalStringMask = 0x10;

+const uint32_t kShortExternalStringTag = 0x10;

// A ConsString with an empty string as the right side is a candidate

// for being shortcut by the garbage collector unless it is a

@@ -478,6 +513,13 @@ enum InstanceType {

ASCII_SYMBOL_TYPE = kAsciiStringTag | kSymbolTag | kSeqStringTag,

CONS_SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag | kConsStringTag,

CONS_ASCII_SYMBOL_TYPE = kAsciiStringTag | kSymbolTag | kConsStringTag,

+ SHORT_EXTERNAL_SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag |

+ kExternalStringTag | kShortExternalStringTag,

+ SHORT_EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE =

+ kTwoByteStringTag | kSymbolTag | kExternalStringTag |

+ kAsciiDataHintTag | kShortExternalStringTag,

+ SHORT_EXTERNAL_ASCII_SYMBOL_TYPE = kAsciiStringTag | kExternalStringTag |

+ kSymbolTag | kShortExternalStringTag,

EXTERNAL_SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag | kExternalStringTag,

EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE =

kTwoByteStringTag | kSymbolTag | kExternalStringTag | kAsciiDataHintTag,

@@ -489,6 +531,13 @@ enum InstanceType {

CONS_ASCII_STRING_TYPE = kAsciiStringTag | kConsStringTag,

SLICED_STRING_TYPE = kTwoByteStringTag | kSlicedStringTag,

SLICED_ASCII_STRING_TYPE = kAsciiStringTag | kSlicedStringTag,

+ SHORT_EXTERNAL_STRING_TYPE =

+ kTwoByteStringTag | kExternalStringTag | kShortExternalStringTag,

+ SHORT_EXTERNAL_STRING_WITH_ASCII_DATA_TYPE =

+ kTwoByteStringTag | kExternalStringTag |

+ kAsciiDataHintTag | kShortExternalStringTag,

+ SHORT_EXTERNAL_ASCII_STRING_TYPE =

+ kAsciiStringTag | kExternalStringTag | kShortExternalStringTag,

EXTERNAL_STRING_TYPE = kTwoByteStringTag | kExternalStringTag,

EXTERNAL_STRING_WITH_ASCII_DATA_TYPE =

kTwoByteStringTag | kExternalStringTag | kAsciiDataHintTag,

@@ -6755,12 +6804,12 @@ class ExternalString: public String {

// Layout description.

static const int kResourceOffset = POINTER_SIZE_ALIGN(String::kSize);

+ static const int kShortSize = kResourceOffset + kPointerSize;

static const int kResourceDataOffset = kResourceOffset + kPointerSize;

static const int kSize = kResourceDataOffset + kPointerSize;

- // Clear the cached pointer to the character array provided by the resource.

- // This cache is updated the first time the character array is accessed.

- inline void clear_data_cache();

+ // Return whether external string is short (data pointer is not cached).

+ inline bool is_short();

STATIC_CHECK(kResourceOffset == Internals::kStringResourceOffset);

@@ -6781,6 +6830,12 @@ class ExternalAsciiString: public ExternalString {

inline const Resource* resource();

inline void set_resource(const Resource* buffer);

+ // Update the pointer cache to the external character array.

+ // The cached pointer is always valid, as the external character array does =

+ // not move during lifetime. Deserialization is the only exception, after

+ // which the pointer cache has to be refreshed.

+ inline void update_data_cache();

inline const char* GetChars();

// Dispatched behavior.

@@ -6820,6 +6875,12 @@ class ExternalTwoByteString: public ExternalString {

inline const Resource* resource();

inline void set_resource(const Resource* buffer);

+ // Update the pointer cache to the external character array.

+ // The cached pointer is always valid, as the external character array does =

+ // not move during lifetime. Deserialization is the only exception, after

+ // which the pointer cache has to be refreshed.

+ inline void update_data_cache();

inline const uint16_t* GetChars();

// Dispatched behavior.

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