// 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_UTILS_H_
#define V8_UTILS_H_
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <cmath>
#include "include/v8.h"
#include "src/allocation.h"
#include "src/base/bits.h"
#include "src/base/compiler-specific.h"
#include "src/base/logging.h"
#include "src/base/macros.h"
#include "src/base/platform/platform.h"
#include "src/globals.h"
#include "src/list.h"
#include "src/vector.h"
#include "src/zone/zone.h"
namespace v8 {
namespace internal {
// ----------------------------------------------------------------------------
// General helper functions
// Returns the value (0 .. 15) of a hexadecimal character c.
// If c is not a legal hexadecimal character, returns a value < 0.
inline int HexValue(uc32 c) {
c -= '0';
if (static_cast<unsigned>(c) <= 9) return c;
c = (c | 0x20) - ('a' - '0'); // detect 0x11..0x16 and 0x31..0x36.
if (static_cast<unsigned>(c) <= 5) return c + 10;
return -1;
}
inline char HexCharOfValue(int value) {
DCHECK(0 <= value && value <= 16);
if (value < 10) return value + '0';
return value - 10 + 'A';
}
inline int BoolToInt(bool b) { return b ? 1 : 0; }
// Same as strcmp, but can handle NULL arguments.
inline bool CStringEquals(const char* s1, const char* s2) {
return (s1 == s2) || (s1 != NULL && s2 != NULL && strcmp(s1, s2) == 0);
}
// X must be a power of 2. Returns the number of trailing zeros.
inline int WhichPowerOf2(uint32_t x) {
DCHECK(base::bits::IsPowerOfTwo32(x));
int bits = 0;
#ifdef DEBUG
uint32_t original_x = x;
#endif
if (x >= 0x10000) {
bits += 16;
x >>= 16;
}
if (x >= 0x100) {
bits += 8;
x >>= 8;
}
if (x >= 0x10) {
bits += 4;
x >>= 4;
}
switch (x) {
default: UNREACHABLE();
case 8: bits++; // Fall through.
case 4: bits++; // Fall through.
case 2: bits++; // Fall through.
case 1: break;
}
DCHECK_EQ(static_cast<uint32_t>(1) << bits, original_x);
return bits;
}
// X must be a power of 2. Returns the number of trailing zeros.
inline int WhichPowerOf2_64(uint64_t x) {
DCHECK(base::bits::IsPowerOfTwo64(x));
int bits = 0;
#ifdef DEBUG
uint64_t original_x = x;
#endif
if (x >= 0x100000000L) {
bits += 32;
x >>= 32;
}
if (x >= 0x10000) {
bits += 16;
x >>= 16;
}
if (x >= 0x100) {
bits += 8;
x >>= 8;
}
if (x >= 0x10) {
bits += 4;
x >>= 4;
}
switch (x) {
default: UNREACHABLE();
case 8: bits++; // Fall through.
case 4: bits++; // Fall through.
case 2: bits++; // Fall through.
case 1: break;
}
DCHECK_EQ(static_cast<uint64_t>(1) << bits, original_x);
return bits;
}
inline int MostSignificantBit(uint32_t x) {
static const int msb4[] = {0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4};
int nibble = 0;
if (x & 0xffff0000) {
nibble += 16;
x >>= 16;
}
if (x & 0xff00) {
nibble += 8;
x >>= 8;
}
if (x & 0xf0) {
nibble += 4;
x >>= 4;
}
return nibble + msb4[x];
}
template <typename T>
static T ArithmeticShiftRight(T x, int shift) {
DCHECK_LE(0, shift);
if (x < 0) {
// Right shift of signed values is implementation defined. Simulate a
// true arithmetic right shift by adding leading sign bits.
using UnsignedT = typename std::make_unsigned<T>::type;
UnsignedT mask = ~(static_cast<UnsignedT>(~0) >> shift);
return (static_cast<UnsignedT>(x) >> shift) | mask;
} else {
return x >> shift;
}
}
template <typename T>
int Compare(const T& a, const T& b) {
if (a == b)
return 0;
else if (a < b)
return -1;
else
return 1;
}
template <typename T>
int PointerValueCompare(const T* a, const T* b) {
return Compare<T>(*a, *b);
}
// Compare function to compare the object pointer value of two
// handlified objects. The handles are passed as pointers to the
// handles.
template<typename T> class Handle; // Forward declaration.
template <typename T>
int HandleObjectPointerCompare(const Handle<T>* a, const Handle<T>* b) {
return Compare<T*>(*(*a), *(*b));
}
template <typename T, typename U>
inline bool IsAligned(T value, U alignment) {
return (value & (alignment - 1)) == 0;
}
// Returns true if (addr + offset) is aligned.
inline bool IsAddressAligned(Address addr,
intptr_t alignment,
int offset = 0) {
intptr_t offs = OffsetFrom(addr + offset);
return IsAligned(offs, alignment);
}
template <typename T, typename U>
inline T RoundUpToMultipleOfPowOf2(T value, U multiple) {
DCHECK(multiple && ((multiple & (multiple - 1)) == 0));
return (value + multiple - 1) & ~(multiple - 1);
}
// Returns the maximum of the two parameters.
template <typename T>
T Max(T a, T b) {
return a < b ? b : a;
}
// Returns the minimum of the two parameters.
template <typename T>
T Min(T a, T b) {
return a < b ? a : b;
}
// Returns the maximum of the two parameters according to JavaScript semantics.
template <typename T>
T JSMax(T x, T y) {
if (std::isnan(x)) return x;
if (std::isnan(y)) return y;
if (std::signbit(x) < std::signbit(y)) return x;
return x > y ? x : y;
}
// Returns the maximum of the two parameters according to JavaScript semantics.
template <typename T>
T JSMin(T x, T y) {
if (std::isnan(x)) return x;
if (std::isnan(y)) return y;
if (std::signbit(x) < std::signbit(y)) return y;
return x > y ? y : x;
}
// Returns the absolute value of its argument.
template <typename T>
T Abs(T a) {
return a < 0 ? -a : a;
}
// Floor(-0.0) == 0.0
inline double Floor(double x) {
#if V8_CC_MSVC
if (x == 0) return x; // Fix for issue 3477.
#endif
return std::floor(x);
}
inline double Pow(double x, double y) {
if (y == 0.0) return 1.0;
if (std::isnan(y) || ((x == 1 || x == -1) && std::isinf(y))) {
return std::numeric_limits<double>::quiet_NaN();
}
#if (defined(__MINGW64_VERSION_MAJOR) && \
(!defined(__MINGW64_VERSION_RC) || __MINGW64_VERSION_RC < 1)) || \
defined(V8_OS_AIX)
// MinGW64 and AIX have a custom implementation for pow. This handles certain
// special cases that are different.
if ((x == 0.0 || std::isinf(x)) && y != 0.0 && std::isfinite(y)) {
double f;
double result = ((x == 0.0) ^ (y > 0)) ? V8_INFINITY : 0;
/* retain sign if odd integer exponent */
return ((std::modf(y, &f) == 0.0) && (static_cast<int64_t>(y) & 1))
? copysign(result, x)
: result;
}
if (x == 2.0) {
int y_int = static_cast<int>(y);
if (y == y_int) {
return std::ldexp(1.0, y_int);
}
}
#endif
return std::pow(x, y);
}
// TODO(svenpanne) Clean up the whole power-of-2 mess.
inline int32_t WhichPowerOf2Abs(int32_t x) {
return (x == kMinInt) ? 31 : WhichPowerOf2(Abs(x));
}
// Obtains the unsigned type corresponding to T
// available in C++11 as std::make_unsigned
template<typename T>
struct make_unsigned {
typedef T type;
};
// Template specializations necessary to have make_unsigned work
template<> struct make_unsigned<int32_t> {
typedef uint32_t type;
};
template<> struct make_unsigned<int64_t> {
typedef uint64_t type;
};
// ----------------------------------------------------------------------------
// BitField is a help template for encoding and decode bitfield with
// unsigned content.
template<class T, int shift, int size, class U>
class BitFieldBase {
public:
// A type U mask of bit field. To use all bits of a type U of x bits
// in a bitfield without compiler warnings we have to compute 2^x
// without using a shift count of x in the computation.
static const U kOne = static_cast<U>(1U);
static const U kMask = ((kOne << shift) << size) - (kOne << shift);
static const U kShift = shift;
static const U kSize = size;
static const U kNext = kShift + kSize;
// Value for the field with all bits set.
static const T kMax = static_cast<T>((kOne << size) - 1);
// Tells whether the provided value fits into the bit field.
static bool is_valid(T value) {
return (static_cast<U>(value) & ~static_cast<U>(kMax)) == 0;
}
// Returns a type U with the bit field value encoded.
static U encode(T value) {
DCHECK(is_valid(value));
return static_cast<U>(value) << shift;
}
// Returns a type U with the bit field value updated.
static U update(U previous, T value) {
return (previous & ~kMask) | encode(value);
}
// Extracts the bit field from the value.
static T decode(U value) {
return static_cast<T>((value & kMask) >> shift);
}
STATIC_ASSERT((kNext - 1) / 8 < sizeof(U));
};
template <class T, int shift, int size>
class BitField8 : public BitFieldBase<T, shift, size, uint8_t> {};
template <class T, int shift, int size>
class BitField16 : public BitFieldBase<T, shift, size, uint16_t> {};
template<class T, int shift, int size>
class BitField : public BitFieldBase<T, shift, size, uint32_t> { };
template<class T, int shift, int size>
class BitField64 : public BitFieldBase<T, shift, size, uint64_t> { };
// ----------------------------------------------------------------------------
// BitSetComputer is a help template for encoding and decoding information for
// a variable number of items in an array.
//
// To encode boolean data in a smi array you would use:
// typedef BitSetComputer<bool, 1, kSmiValueSize, uint32_t> BoolComputer;
//
template <class T, int kBitsPerItem, int kBitsPerWord, class U>
class BitSetComputer {
public:
static const int kItemsPerWord = kBitsPerWord / kBitsPerItem;
static const int kMask = (1 << kBitsPerItem) - 1;
// The number of array elements required to embed T information for each item.
static int word_count(int items) {
if (items == 0) return 0;
return (items - 1) / kItemsPerWord + 1;
}
// The array index to look at for item.
static int index(int base_index, int item) {
return base_index + item / kItemsPerWord;
}
// Extract T data for a given item from data.
static T decode(U data, int item) {
return static_cast<T>((data >> shift(item)) & kMask);
}
// Return the encoding for a store of value for item in previous.
static U encode(U previous, int item, T value) {
int shift_value = shift(item);
int set_bits = (static_cast<int>(value) << shift_value);
return (previous & ~(kMask << shift_value)) | set_bits;
}
static int shift(int item) { return (item % kItemsPerWord) * kBitsPerItem; }
};
// ----------------------------------------------------------------------------
// Hash function.
static const uint32_t kZeroHashSeed = 0;
// Thomas Wang, Integer Hash Functions.
// http://www.concentric.net/~Ttwang/tech/inthash.htm
inline uint32_t ComputeIntegerHash(uint32_t key, uint32_t seed) {
uint32_t hash = key;
hash = hash ^ seed;
hash = ~hash + (hash << 15); // hash = (hash << 15) - hash - 1;
hash = hash ^ (hash >> 12);
hash = hash + (hash << 2);
hash = hash ^ (hash >> 4);
hash = hash * 2057; // hash = (hash + (hash << 3)) + (hash << 11);
hash = hash ^ (hash >> 16);
return hash & 0x3fffffff;
}
inline uint32_t ComputeLongHash(uint64_t key) {
uint64_t hash = key;
hash = ~hash + (hash << 18); // hash = (hash << 18) - hash - 1;
hash = hash ^ (hash >> 31);
hash = hash * 21; // hash = (hash + (hash << 2)) + (hash << 4);
hash = hash ^ (hash >> 11);
hash = hash + (hash << 6);
hash = hash ^ (hash >> 22);
return static_cast<uint32_t>(hash);
}
inline uint32_t ComputePointerHash(void* ptr) {
return ComputeIntegerHash(
static_cast<uint32_t>(reinterpret_cast<intptr_t>(ptr)),
v8::internal::kZeroHashSeed);
}
// ----------------------------------------------------------------------------
// Generated memcpy/memmove
// Initializes the codegen support that depends on CPU features.
void init_memcopy_functions(Isolate* isolate);
#if defined(V8_TARGET_ARCH_IA32) || defined(V8_TARGET_ARCH_X87)
// Limit below which the extra overhead of the MemCopy function is likely
// to outweigh the benefits of faster copying.
const int kMinComplexMemCopy = 64;
// Copy memory area. No restrictions.
V8_EXPORT_PRIVATE void MemMove(void* dest, const void* src, size_t size);
typedef void (*MemMoveFunction)(void* dest, const void* src, size_t size);
// Keep the distinction of "move" vs. "copy" for the benefit of other
// architectures.
V8_INLINE void MemCopy(void* dest, const void* src, size_t size) {
MemMove(dest, src, size);
}
#elif defined(V8_HOST_ARCH_ARM)
typedef void (*MemCopyUint8Function)(uint8_t* dest, const uint8_t* src,
size_t size);
V8_EXPORT_PRIVATE extern MemCopyUint8Function memcopy_uint8_function;
V8_INLINE void MemCopyUint8Wrapper(uint8_t* dest, const uint8_t* src,
size_t chars) {
memcpy(dest, src, chars);
}
// For values < 16, the assembler function is slower than the inlined C code.
const int kMinComplexMemCopy = 16;
V8_INLINE void MemCopy(void* dest, const void* src, size_t size) {
(*memcopy_uint8_function)(reinterpret_cast<uint8_t*>(dest),
reinterpret_cast<const uint8_t*>(src), size);
}
V8_EXPORT_PRIVATE V8_INLINE void MemMove(void* dest, const void* src,
size_t size) {
memmove(dest, src, size);
}
typedef void (*MemCopyUint16Uint8Function)(uint16_t* dest, const uint8_t* src,
size_t size);
extern MemCopyUint16Uint8Function memcopy_uint16_uint8_function;
void MemCopyUint16Uint8Wrapper(uint16_t* dest, const uint8_t* src,
size_t chars);
// For values < 12, the assembler function is slower than the inlined C code.
const int kMinComplexConvertMemCopy = 12;
V8_INLINE void MemCopyUint16Uint8(uint16_t* dest, const uint8_t* src,
size_t size) {
(*memcopy_uint16_uint8_function)(dest, src, size);
}
#elif defined(V8_HOST_ARCH_MIPS)
typedef void (*MemCopyUint8Function)(uint8_t* dest, const uint8_t* src,
size_t size);
V8_EXPORT_PRIVATE extern MemCopyUint8Function memcopy_uint8_function;
V8_INLINE void MemCopyUint8Wrapper(uint8_t* dest, const uint8_t* src,
size_t chars) {
memcpy(dest, src, chars);
}
// For values < 16, the assembler function is slower than the inlined C code.
const int kMinComplexMemCopy = 16;
V8_INLINE void MemCopy(void* dest, const void* src, size_t size) {
(*memcopy_uint8_function)(reinterpret_cast<uint8_t*>(dest),
reinterpret_cast<const uint8_t*>(src), size);
}
V8_EXPORT_PRIVATE V8_INLINE void MemMove(void* dest, const void* src,
size_t size) {
memmove(dest, src, size);
}
#else
// Copy memory area to disjoint memory area.
V8_INLINE void MemCopy(void* dest, const void* src, size_t size) {
memcpy(dest, src, size);
}
V8_EXPORT_PRIVATE V8_INLINE void MemMove(void* dest, const void* src,
size_t size) {
memmove(dest, src, size);
}
const int kMinComplexMemCopy = 8;
#endif // V8_TARGET_ARCH_IA32
// ----------------------------------------------------------------------------
// Miscellaneous
// Memory offset for lower and higher bits in a 64 bit integer.
#if defined(V8_TARGET_LITTLE_ENDIAN)
static const int kInt64LowerHalfMemoryOffset = 0;
static const int kInt64UpperHalfMemoryOffset = 4;
#elif defined(V8_TARGET_BIG_ENDIAN)
static const int kInt64LowerHalfMemoryOffset = 4;
static const int kInt64UpperHalfMemoryOffset = 0;
#endif // V8_TARGET_LITTLE_ENDIAN
// A static resource holds a static instance that can be reserved in
// a local scope using an instance of Access. Attempts to re-reserve
// the instance will cause an error.
template <typename T>
class StaticResource {
public:
StaticResource() : is_reserved_(false) {}
private:
template <typename S> friend class Access;
T instance_;
bool is_reserved_;
};
// Locally scoped access to a static resource.
template <typename T>
class Access {
public:
explicit Access(StaticResource<T>* resource)
: resource_(resource)
, instance_(&resource->instance_) {
DCHECK(!resource->is_reserved_);
resource->is_reserved_ = true;
}
~Access() {
resource_->is_reserved_ = false;
resource_ = NULL;
instance_ = NULL;
}
T* value() { return instance_; }
T* operator -> () { return instance_; }
private:
StaticResource<T>* resource_;
T* instance_;
};
// A pointer that can only be set once and doesn't allow NULL values.
template<typename T>
class SetOncePointer {
public:
SetOncePointer() : pointer_(NULL) { }
bool is_set() const { return pointer_ != NULL; }
T* get() const {
DCHECK(pointer_ != NULL);
return pointer_;
}
void set(T* value) {
DCHECK(pointer_ == NULL && value != NULL);
pointer_ = value;
}
private:
T* pointer_;
};
template <typename T, int kSize>
class EmbeddedVector : public Vector<T> {
public:
EmbeddedVector() : Vector<T>(buffer_, kSize) { }
explicit EmbeddedVector(T initial_value) : Vector<T>(buffer_, kSize) {
for (int i = 0; i < kSize; ++i) {
buffer_[i] = initial_value;
}
}
// When copying, make underlying Vector to reference our buffer.
EmbeddedVector(const EmbeddedVector& rhs)
: Vector<T>(rhs) {
MemCopy(buffer_, rhs.buffer_, sizeof(T) * kSize);
this->set_start(buffer_);
}
EmbeddedVector& operator=(const EmbeddedVector& rhs) {
if (this == &rhs) return *this;
Vector<T>::operator=(rhs);
MemCopy(buffer_, rhs.buffer_, sizeof(T) * kSize);
this->set_start(buffer_);
return *this;
}
private:
T buffer_[kSize];
};
// Compare 8bit/16bit chars to 8bit/16bit chars.
template <typename lchar, typename rchar>
inline int CompareCharsUnsigned(const lchar* lhs, const rchar* rhs,
size_t chars) {
const lchar* limit = lhs + chars;
if (sizeof(*lhs) == sizeof(char) && sizeof(*rhs) == sizeof(char)) {
// memcmp compares byte-by-byte, yielding wrong results for two-byte
// strings on little-endian systems.
return memcmp(lhs, rhs, chars);
}
while (lhs < limit) {
int r = static_cast<int>(*lhs) - static_cast<int>(*rhs);
if (r != 0) return r;
++lhs;
++rhs;
}
return 0;
}
template <typename lchar, typename rchar>
inline int CompareChars(const lchar* lhs, const rchar* rhs, size_t chars) {
DCHECK(sizeof(lchar) <= 2);
DCHECK(sizeof(rchar) <= 2);
if (sizeof(lchar) == 1) {
if (sizeof(rchar) == 1) {
return CompareCharsUnsigned(reinterpret_cast<const uint8_t*>(lhs),
reinterpret_cast<const uint8_t*>(rhs),
chars);
} else {
return CompareCharsUnsigned(reinterpret_cast<const uint8_t*>(lhs),
reinterpret_cast<const uint16_t*>(rhs),
chars);
}
} else {
if (sizeof(rchar) == 1) {
return CompareCharsUnsigned(reinterpret_cast<const uint16_t*>(lhs),
reinterpret_cast<const uint8_t*>(rhs),
chars);
} else {
return CompareCharsUnsigned(reinterpret_cast<const uint16_t*>(lhs),
reinterpret_cast<const uint16_t*>(rhs),
chars);
}
}
}
// Calculate 10^exponent.
inline int TenToThe(int exponent) {
DCHECK(exponent <= 9);
DCHECK(exponent >= 1);
int answer = 10;
for (int i = 1; i < exponent; i++) answer *= 10;
return answer;
}
template<typename ElementType, int NumElements>
class EmbeddedContainer {
public:
EmbeddedContainer() : elems_() { }
int length() const { return NumElements; }
const ElementType& operator[](int i) const {
DCHECK(i < length());
return elems_[i];
}
ElementType& operator[](int i) {
DCHECK(i < length());
return elems_[i];
}
private:
ElementType elems_[NumElements];
};
template<typename ElementType>
class EmbeddedContainer<ElementType, 0> {
public:
int length() const { return 0; }
const ElementType& operator[](int i) const {
UNREACHABLE();
static ElementType t = 0;
return t;
}
ElementType& operator[](int i) {
UNREACHABLE();
static ElementType t = 0;
return t;
}
};
// Helper class for building result strings in a character buffer. The
// purpose of the class is to use safe operations that checks the
// buffer bounds on all operations in debug mode.
// This simple base class does not allow formatted output.
class SimpleStringBuilder {
public:
// Create a string builder with a buffer of the given size. The
// buffer is allocated through NewArray<char> and must be
// deallocated by the caller of Finalize().
explicit SimpleStringBuilder(int size);
SimpleStringBuilder(char* buffer, int size)
: buffer_(buffer, size), position_(0) { }
~SimpleStringBuilder() { if (!is_finalized()) Finalize(); }
int size() const { return buffer_.length(); }
// Get the current position in the builder.
int position() const {
DCHECK(!is_finalized());
return position_;
}
// Reset the position.
void Reset() { position_ = 0; }
// Add a single character to the builder. It is not allowed to add
// 0-characters; use the Finalize() method to terminate the string
// instead.
void AddCharacter(char c) {
DCHECK(c != '\0');
DCHECK(!is_finalized() && position_ < buffer_.length());
buffer_[position_++] = c;
}
// Add an entire string to the builder. Uses strlen() internally to
// compute the length of the input string.
void AddString(const char* s);
// Add the first 'n' characters of the given 0-terminated string 's' to the
// builder. The input string must have enough characters.
void AddSubstring(const char* s, int n);
// Add character padding to the builder. If count is non-positive,
// nothing is added to the builder.
void AddPadding(char c, int count);
// Add the decimal representation of the value.
void AddDecimalInteger(int value);
// Finalize the string by 0-terminating it and returning the buffer.
char* Finalize();
protected:
Vector<char> buffer_;
int position_;
bool is_finalized() const { return position_ < 0; }
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(SimpleStringBuilder);
};
// A poor man's version of STL's bitset: A bit set of enums E (without explicit
// values), fitting into an integral type T.
template <class E, class T = int>
class EnumSet {
public:
explicit EnumSet(T bits = 0) : bits_(bits) {}
bool IsEmpty() const { return bits_ == 0; }
bool Contains(E element) const { return (bits_ & Mask(element)) != 0; }
bool ContainsAnyOf(const EnumSet& set) const {
return (bits_ & set.bits_) != 0;
}
void Add(E element) { bits_ |= Mask(element); }
void Add(const EnumSet& set) { bits_ |= set.bits_; }
void Remove(E element) { bits_ &= ~Mask(element); }
void Remove(const EnumSet& set) { bits_ &= ~set.bits_; }
void RemoveAll() { bits_ = 0; }
void Intersect(const EnumSet& set) { bits_ &= set.bits_; }
T ToIntegral() const { return bits_; }
bool operator==(const EnumSet& set) { return bits_ == set.bits_; }
bool operator!=(const EnumSet& set) { return bits_ != set.bits_; }
EnumSet<E, T> operator|(const EnumSet& set) const {
return EnumSet<E, T>(bits_ | set.bits_);
}
private:
T Mask(E element) const {
// The strange typing in DCHECK is necessary to avoid stupid warnings, see:
// http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43680
DCHECK(static_cast<int>(element) < static_cast<int>(sizeof(T) * CHAR_BIT));
return static_cast<T>(1) << element;
}
T bits_;
};
// Bit field extraction.
inline uint32_t unsigned_bitextract_32(int msb, int lsb, uint32_t x) {
return (x >> lsb) & ((1 << (1 + msb - lsb)) - 1);
}
inline uint64_t unsigned_bitextract_64(int msb, int lsb, uint64_t x) {
return (x >> lsb) & ((static_cast<uint64_t>(1) << (1 + msb - lsb)) - 1);
}
inline int32_t signed_bitextract_32(int msb, int lsb, int32_t x) {
return (x << (31 - msb)) >> (lsb + 31 - msb);
}
inline int signed_bitextract_64(int msb, int lsb, int x) {
// TODO(jbramley): This is broken for big bitfields.
return (x << (63 - msb)) >> (lsb + 63 - msb);
}
// Check number width.
inline bool is_intn(int64_t x, unsigned n) {
DCHECK((0 < n) && (n < 64));
int64_t limit = static_cast<int64_t>(1) << (n - 1);
return (-limit <= x) && (x < limit);
}
inline bool is_uintn(int64_t x, unsigned n) {
DCHECK((0 < n) && (n < (sizeof(x) * kBitsPerByte)));
return !(x >> n);
}
template <class T>
inline T truncate_to_intn(T x, unsigned n) {
DCHECK((0 < n) && (n < (sizeof(x) * kBitsPerByte)));
return (x & ((static_cast<T>(1) << n) - 1));
}
#define INT_1_TO_63_LIST(V) \
V(1) V(2) V(3) V(4) V(5) V(6) V(7) V(8) \
V(9) V(10) V(11) V(12) V(13) V(14) V(15) V(16) \
V(17) V(18) V(19) V(20) V(21) V(22) V(23) V(24) \
V(25) V(26) V(27) V(28) V(29) V(30) V(31) V(32) \
V(33) V(34) V(35) V(36) V(37) V(38) V(39) V(40) \
V(41) V(42) V(43) V(44) V(45) V(46) V(47) V(48) \
V(49) V(50) V(51) V(52) V(53) V(54) V(55) V(56) \
V(57) V(58) V(59) V(60) V(61) V(62) V(63)
#define DECLARE_IS_INT_N(N) \
inline bool is_int##N(int64_t x) { return is_intn(x, N); }
#define DECLARE_IS_UINT_N(N) \
template <class T> \
inline bool is_uint##N(T x) { return is_uintn(x, N); }
#define DECLARE_TRUNCATE_TO_INT_N(N) \
template <class T> \
inline T truncate_to_int##N(T x) { return truncate_to_intn(x, N); }
INT_1_TO_63_LIST(DECLARE_IS_INT_N)
INT_1_TO_63_LIST(DECLARE_IS_UINT_N)
INT_1_TO_63_LIST(DECLARE_TRUNCATE_TO_INT_N)
#undef DECLARE_IS_INT_N
#undef DECLARE_IS_UINT_N
#undef DECLARE_TRUNCATE_TO_INT_N
class TypeFeedbackId {
public:
explicit TypeFeedbackId(int id) : id_(id) { }
int ToInt() const { return id_; }
static TypeFeedbackId None() { return TypeFeedbackId(kNoneId); }
bool IsNone() const { return id_ == kNoneId; }
private:
static const int kNoneId = -1;
int id_;
};
inline bool operator<(TypeFeedbackId lhs, TypeFeedbackId rhs) {
return lhs.ToInt() < rhs.ToInt();
}
inline bool operator>(TypeFeedbackId lhs, TypeFeedbackId rhs) {
return lhs.ToInt() > rhs.ToInt();
}
class FeedbackSlot {
public:
FeedbackSlot() : id_(kInvalidSlot) {}
explicit FeedbackSlot(int id) : id_(id) {}
int ToInt() const { return id_; }
static FeedbackSlot Invalid() { return FeedbackSlot(); }
bool IsInvalid() const { return id_ == kInvalidSlot; }
bool operator==(FeedbackSlot that) const { return this->id_ == that.id_; }
bool operator!=(FeedbackSlot that) const { return !(*this == that); }
friend size_t hash_value(FeedbackSlot slot) { return slot.ToInt(); }
friend std::ostream& operator<<(std::ostream& os, FeedbackSlot);
private:
static const int kInvalidSlot = -1;
int id_;
};
class BailoutId {
public:
explicit BailoutId(int id) : id_(id) { }
int ToInt() const { return id_; }
static BailoutId None() { return BailoutId(kNoneId); }
static BailoutId ScriptContext() { return BailoutId(kScriptContextId); }
static BailoutId FunctionContext() { return BailoutId(kFunctionContextId); }
static BailoutId FunctionEntry() { return BailoutId(kFunctionEntryId); }
static BailoutId Declarations() { return BailoutId(kDeclarationsId); }
static BailoutId FirstUsable() { return BailoutId(kFirstUsableId); }
static BailoutId StubEntry() { return BailoutId(kStubEntryId); }
// Special bailout id support for deopting into the {JSConstructStub} stub.
// The following hard-coded deoptimization points are supported by the stub:
// - {ConstructStubCreate} maps to {construct_stub_create_deopt_pc_offset}.
// - {ConstructStubInvoke} maps to {construct_stub_invoke_deopt_pc_offset}.
static BailoutId ConstructStubCreate() { return BailoutId(1); }
static BailoutId ConstructStubInvoke() { return BailoutId(2); }
bool IsValidForConstructStub() const {
return id_ == ConstructStubCreate().ToInt() ||
id_ == ConstructStubInvoke().ToInt();
}
bool IsNone() const { return id_ == kNoneId; }
bool operator==(const BailoutId& other) const { return id_ == other.id_; }
bool operator!=(const BailoutId& other) const { return id_ != other.id_; }
friend size_t hash_value(BailoutId);
V8_EXPORT_PRIVATE friend std::ostream& operator<<(std::ostream&, BailoutId);
private:
static const int kNoneId = -1;
// Using 0 could disguise errors.
static const int kScriptContextId = 1;
static const int kFunctionContextId = 2;
static const int kFunctionEntryId = 3;
// This AST id identifies the point after the declarations have been visited.
// We need it to capture the environment effects of declarations that emit
// code (function declarations).
static const int kDeclarationsId = 4;
// Every FunctionState starts with this id.
static const int kFirstUsableId = 5;
// Every compiled stub starts with this id.
static const int kStubEntryId = 6;
int id_;
};
// ----------------------------------------------------------------------------
// I/O support.
// Our version of printf().
V8_EXPORT_PRIVATE void PRINTF_FORMAT(1, 2) PrintF(const char* format, ...);
void PRINTF_FORMAT(2, 3) PrintF(FILE* out, const char* format, ...);
// Prepends the current process ID to the output.
void PRINTF_FORMAT(1, 2) PrintPID(const char* format, ...);
// Prepends the current process ID and given isolate pointer to the output.
void PRINTF_FORMAT(2, 3) PrintIsolate(void* isolate, const char* format, ...);
// Safe formatting print. Ensures that str is always null-terminated.
// Returns the number of chars written, or -1 if output was truncated.
int PRINTF_FORMAT(2, 3) SNPrintF(Vector<char> str, const char* format, ...);
int PRINTF_FORMAT(2, 0)
VSNPrintF(Vector<char> str, const char* format, va_list args);
void StrNCpy(Vector<char> dest, const char* src, size_t n);
// Our version of fflush.
void Flush(FILE* out);
inline void Flush() {
Flush(stdout);
}
// Read a line of characters after printing the prompt to stdout. The resulting
// char* needs to be disposed off with DeleteArray by the caller.
char* ReadLine(const char* prompt);
// Read and return the raw bytes in a file. the size of the buffer is returned
// in size.
// The returned buffer must be freed by the caller.
byte* ReadBytes(const char* filename, int* size, bool verbose = true);
// Append size chars from str to the file given by filename.
// The file is overwritten. Returns the number of chars written.
int AppendChars(const char* filename,
const char* str,
int size,
bool verbose = true);
// Write size chars from str to the file given by filename.
// The file is overwritten. Returns the number of chars written.
int WriteChars(const char* filename,
const char* str,
int size,
bool verbose = true);
// Write size bytes to the file given by filename.
// The file is overwritten. Returns the number of bytes written.
int WriteBytes(const char* filename,
const byte* bytes,
int size,
bool verbose = true);
// Write the C code
// const char* <varname> = "<str>";
// const int <varname>_len = <len>;
// to the file given by filename. Only the first len chars are written.
int WriteAsCFile(const char* filename, const char* varname,
const char* str, int size, bool verbose = true);
// ----------------------------------------------------------------------------
// Memory
// Copies words from |src| to |dst|. The data spans must not overlap.
template <typename T>
inline void CopyWords(T* dst, const T* src, size_t num_words) {
STATIC_ASSERT(sizeof(T) == kPointerSize);
// TODO(mvstanton): disabled because mac builds are bogus failing on this
// assert. They are doing a signed comparison. Investigate in
// the morning.
// DCHECK(Min(dst, const_cast<T*>(src)) + num_words <=
// Max(dst, const_cast<T*>(src)));
DCHECK(num_words > 0);
// Use block copying MemCopy if the segment we're copying is
// enough to justify the extra call/setup overhead.
static const size_t kBlockCopyLimit = 16;
if (num_words < kBlockCopyLimit) {
do {
num_words--;
*dst++ = *src++;
} while (num_words > 0);
} else {
MemCopy(dst, src, num_words * kPointerSize);
}
}
// Copies words from |src| to |dst|. No restrictions.
template <typename T>
inline void MoveWords(T* dst, const T* src, size_t num_words) {
STATIC_ASSERT(sizeof(T) == kPointerSize);
DCHECK(num_words > 0);
// Use block copying MemCopy if the segment we're copying is
// enough to justify the extra call/setup overhead.
static const size_t kBlockCopyLimit = 16;
if (num_words < kBlockCopyLimit &&
((dst < src) || (dst >= (src + num_words * kPointerSize)))) {
T* end = dst + num_words;
do {
num_words--;
*dst++ = *src++;
} while (num_words > 0);
} else {
MemMove(dst, src, num_words * kPointerSize);
}
}
// Copies data from |src| to |dst|. The data spans must not overlap.
template <typename T>
inline void CopyBytes(T* dst, const T* src, size_t num_bytes) {
STATIC_ASSERT(sizeof(T) == 1);
DCHECK(Min(dst, const_cast<T*>(src)) + num_bytes <=
Max(dst, const_cast<T*>(src)));
if (num_bytes == 0) return;
// Use block copying MemCopy if the segment we're copying is
// enough to justify the extra call/setup overhead.
static const int kBlockCopyLimit = kMinComplexMemCopy;
if (num_bytes < static_cast<size_t>(kBlockCopyLimit)) {
do {
num_bytes--;
*dst++ = *src++;
} while (num_bytes > 0);
} else {
MemCopy(dst, src, num_bytes);
}
}
template <typename T, typename U>
inline void MemsetPointer(T** dest, U* value, int counter) {
#ifdef DEBUG
T* a = NULL;
U* b = NULL;
a = b; // Fake assignment to check assignability.
USE(a);
#endif // DEBUG
#if V8_HOST_ARCH_IA32
#define STOS "stosl"
#elif V8_HOST_ARCH_X64
#if V8_HOST_ARCH_32_BIT
#define STOS "addr32 stosl"
#else
#define STOS "stosq"
#endif
#endif
#if defined(MEMORY_SANITIZER)
// MemorySanitizer does not understand inline assembly.
#undef STOS
#endif
#if defined(__GNUC__) && defined(STOS)
asm volatile(
"cld;"
"rep ; " STOS
: "+&c" (counter), "+&D" (dest)
: "a" (value)
: "memory", "cc");
#else
for (int i = 0; i < counter; i++) {
dest[i] = value;
}
#endif
#undef STOS
}
// Simple support to read a file into a 0-terminated C-string.
// The returned buffer must be freed by the caller.
// On return, *exits tells whether the file existed.
V8_EXPORT_PRIVATE Vector<const char> ReadFile(const char* filename,
bool* exists,
bool verbose = true);
Vector<const char> ReadFile(FILE* file,
bool* exists,
bool verbose = true);
template <typename sourcechar, typename sinkchar>
INLINE(static void CopyCharsUnsigned(sinkchar* dest, const sourcechar* src,
size_t chars));
#if defined(V8_HOST_ARCH_ARM)
INLINE(void CopyCharsUnsigned(uint8_t* dest, const uint8_t* src, size_t chars));
INLINE(void CopyCharsUnsigned(uint16_t* dest, const uint8_t* src,
size_t chars));
INLINE(void CopyCharsUnsigned(uint16_t* dest, const uint16_t* src,
size_t chars));
#elif defined(V8_HOST_ARCH_MIPS)
INLINE(void CopyCharsUnsigned(uint8_t* dest, const uint8_t* src, size_t chars));
INLINE(void CopyCharsUnsigned(uint16_t* dest, const uint16_t* src,
size_t chars));
#elif defined(V8_HOST_ARCH_PPC) || defined(V8_HOST_ARCH_S390)
INLINE(void CopyCharsUnsigned(uint8_t* dest, const uint8_t* src, size_t chars));
INLINE(void CopyCharsUnsigned(uint16_t* dest, const uint16_t* src,
size_t chars));
#endif
// Copy from 8bit/16bit chars to 8bit/16bit chars.
template <typename sourcechar, typename sinkchar>
INLINE(void CopyChars(sinkchar* dest, const sourcechar* src, size_t chars));
template <typename sourcechar, typename sinkchar>
void CopyChars(sinkchar* dest, const sourcechar* src, size_t chars) {
DCHECK(sizeof(sourcechar) <= 2);
DCHECK(sizeof(sinkchar) <= 2);
if (sizeof(sinkchar) == 1) {
if (sizeof(sourcechar) == 1) {
CopyCharsUnsigned(reinterpret_cast<uint8_t*>(dest),
reinterpret_cast<const uint8_t*>(src),
chars);
} else {
CopyCharsUnsigned(reinterpret_cast<uint8_t*>(dest),
reinterpret_cast<const uint16_t*>(src),
chars);
}
} else {
if (sizeof(sourcechar) == 1) {
CopyCharsUnsigned(reinterpret_cast<uint16_t*>(dest),
reinterpret_cast<const uint8_t*>(src),
chars);
} else {
CopyCharsUnsigned(reinterpret_cast<uint16_t*>(dest),
reinterpret_cast<const uint16_t*>(src),
chars);
}
}
}
template <typename sourcechar, typename sinkchar>
void CopyCharsUnsigned(sinkchar* dest, const sourcechar* src, size_t chars) {
sinkchar* limit = dest + chars;
if ((sizeof(*dest) == sizeof(*src)) &&
(chars >= static_cast<int>(kMinComplexMemCopy / sizeof(*dest)))) {
MemCopy(dest, src, chars * sizeof(*dest));
} else {
while (dest < limit) *dest++ = static_cast<sinkchar>(*src++);
}
}
#if defined(V8_HOST_ARCH_ARM)
void CopyCharsUnsigned(uint8_t* dest, const uint8_t* src, size_t chars) {
switch (static_cast<unsigned>(chars)) {
case 0:
break;
case 1:
*dest = *src;
break;
case 2:
memcpy(dest, src, 2);
break;
case 3:
memcpy(dest, src, 3);
break;
case 4:
memcpy(dest, src, 4);
break;
case 5:
memcpy(dest, src, 5);
break;
case 6:
memcpy(dest, src, 6);
break;
case 7:
memcpy(dest, src, 7);
break;
case 8:
memcpy(dest, src, 8);
break;
case 9:
memcpy(dest, src, 9);
break;
case 10:
memcpy(dest, src, 10);
break;
case 11:
memcpy(dest, src, 11);
break;
case 12:
memcpy(dest, src, 12);
break;
case 13:
memcpy(dest, src, 13);
break;
case 14:
memcpy(dest, src, 14);
break;
case 15:
memcpy(dest, src, 15);
break;
default:
MemCopy(dest, src, chars);
break;
}
}
void CopyCharsUnsigned(uint16_t* dest, const uint8_t* src, size_t chars) {
if (chars >= static_cast<size_t>(kMinComplexConvertMemCopy)) {
MemCopyUint16Uint8(dest, src, chars);
} else {
MemCopyUint16Uint8Wrapper(dest, src, chars);
}
}
void CopyCharsUnsigned(uint16_t* dest, const uint16_t* src, size_t chars) {
switch (static_cast<unsigned>(chars)) {
case 0:
break;
case 1:
*dest = *src;
break;
case 2:
memcpy(dest, src, 4);
break;
case 3:
memcpy(dest, src, 6);
break;
case 4:
memcpy(dest, src, 8);
break;
case 5:
memcpy(dest, src, 10);
break;
case 6:
memcpy(dest, src, 12);
break;
case 7:
memcpy(dest, src, 14);
break;
default:
MemCopy(dest, src, chars * sizeof(*dest));
break;
}
}
#elif defined(V8_HOST_ARCH_MIPS)
void CopyCharsUnsigned(uint8_t* dest, const uint8_t* src, size_t chars) {
if (chars < kMinComplexMemCopy) {
memcpy(dest, src, chars);
} else {
MemCopy(dest, src, chars);
}
}
void CopyCharsUnsigned(uint16_t* dest, const uint16_t* src, size_t chars) {
if (chars < kMinComplexMemCopy) {
memcpy(dest, src, chars * sizeof(*dest));
} else {
MemCopy(dest, src, chars * sizeof(*dest));
}
}
#elif defined(V8_HOST_ARCH_PPC) || defined(V8_HOST_ARCH_S390)
#define CASE(n) \
case n: \
memcpy(dest, src, n); \
break
void CopyCharsUnsigned(uint8_t* dest, const uint8_t* src, size_t chars) {
switch (static_cast<unsigned>(chars)) {
case 0:
break;
case 1:
*dest = *src;
break;
CASE(2);
CASE(3);
CASE(4);
CASE(5);
CASE(6);
CASE(7);
CASE(8);
CASE(9);
CASE(10);
CASE(11);
CASE(12);
CASE(13);
CASE(14);
CASE(15);
CASE(16);
CASE(17);
CASE(18);
CASE(19);
CASE(20);
CASE(21);
CASE(22);
CASE(23);
CASE(24);
CASE(25);
CASE(26);
CASE(27);
CASE(28);
CASE(29);
CASE(30);
CASE(31);
CASE(32);
CASE(33);
CASE(34);
CASE(35);
CASE(36);
CASE(37);
CASE(38);
CASE(39);
CASE(40);
CASE(41);
CASE(42);
CASE(43);
CASE(44);
CASE(45);
CASE(46);
CASE(47);
CASE(48);
CASE(49);
CASE(50);
CASE(51);
CASE(52);
CASE(53);
CASE(54);
CASE(55);
CASE(56);
CASE(57);
CASE(58);
CASE(59);
CASE(60);
CASE(61);
CASE(62);
CASE(63);
CASE(64);
default:
memcpy(dest, src, chars);
break;
}
}
#undef CASE
#define CASE(n) \
case n: \
memcpy(dest, src, n * 2); \
break
void CopyCharsUnsigned(uint16_t* dest, const uint16_t* src, size_t chars) {
switch (static_cast<unsigned>(chars)) {
case 0:
break;
case 1:
*dest = *src;
break;
CASE(2);
CASE(3);
CASE(4);
CASE(5);
CASE(6);
CASE(7);
CASE(8);
CASE(9);
CASE(10);
CASE(11);
CASE(12);
CASE(13);
CASE(14);
CASE(15);
CASE(16);
CASE(17);
CASE(18);
CASE(19);
CASE(20);
CASE(21);
CASE(22);
CASE(23);
CASE(24);
CASE(25);
CASE(26);
CASE(27);
CASE(28);
CASE(29);
CASE(30);
CASE(31);
CASE(32);
default:
memcpy(dest, src, chars * 2);
break;
}
}
#undef CASE
#endif
class StringBuilder : public SimpleStringBuilder {
public:
explicit StringBuilder(int size) : SimpleStringBuilder(size) { }
StringBuilder(char* buffer, int size) : SimpleStringBuilder(buffer, size) { }
// Add formatted contents to the builder just like printf().
void PRINTF_FORMAT(2, 3) AddFormatted(const char* format, ...);
// Add formatted contents like printf based on a va_list.
void PRINTF_FORMAT(2, 0) AddFormattedList(const char* format, va_list list);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(StringBuilder);
};
bool DoubleToBoolean(double d);
template <typename Stream>
bool StringToArrayIndex(Stream* stream, uint32_t* index) {
uint16_t ch = stream->GetNext();
// If the string begins with a '0' character, it must only consist
// of it to be a legal array index.
if (ch == '0') {
*index = 0;
return !stream->HasMore();
}
// Convert string to uint32 array index; character by character.
int d = ch - '0';
if (d < 0 || d > 9) return false;
uint32_t result = d;
while (stream->HasMore()) {
d = stream->GetNext() - '0';
if (d < 0 || d > 9) return false;
// Check that the new result is below the 32 bit limit.
if (result > 429496729U - ((d + 3) >> 3)) return false;
result = (result * 10) + d;
}
*index = result;
return true;
}
// Returns current value of top of the stack. Works correctly with ASAN.
DISABLE_ASAN
inline uintptr_t GetCurrentStackPosition() {
// Takes the address of the limit variable in order to find out where
// the top of stack is right now.
uintptr_t limit = reinterpret_cast<uintptr_t>(&limit);
return limit;
}
template <typename V>
static inline V ReadUnalignedValue(const void* p) {
#if !(V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM)
return *reinterpret_cast<const V*>(p);
#else // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM
V r;
memmove(&r, p, sizeof(V));
return r;
#endif // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM
}
template <typename V>
static inline void WriteUnalignedValue(void* p, V value) {
#if !(V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM)
*(reinterpret_cast<V*>(p)) = value;
#else // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM
memmove(p, &value, sizeof(V));
#endif // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM
}
static inline double ReadFloatValue(const void* p) {
return ReadUnalignedValue<float>(p);
}
static inline double ReadDoubleValue(const void* p) {
return ReadUnalignedValue<double>(p);
}
static inline void WriteDoubleValue(void* p, double value) {
WriteUnalignedValue(p, value);
}
static inline uint16_t ReadUnalignedUInt16(const void* p) {
return ReadUnalignedValue<uint16_t>(p);
}
static inline void WriteUnalignedUInt16(void* p, uint16_t value) {
WriteUnalignedValue(p, value);
}
static inline uint32_t ReadUnalignedUInt32(const void* p) {
return ReadUnalignedValue<uint32_t>(p);
}
static inline void WriteUnalignedUInt32(void* p, uint32_t value) {
WriteUnalignedValue(p, value);
}
template <typename V>
static inline V ReadLittleEndianValue(const void* p) {
#if defined(V8_TARGET_LITTLE_ENDIAN)
return ReadUnalignedValue<V>(p);
#elif defined(V8_TARGET_BIG_ENDIAN)
V ret = 0;
const byte* src = reinterpret_cast<const byte*>(p);
byte* dst = reinterpret_cast<byte*>(&ret);
for (size_t i = 0; i < sizeof(V); i++) {
dst[i] = src[sizeof(V) - i - 1];
}
return ret;
#endif // V8_TARGET_LITTLE_ENDIAN
}
template <typename V>
static inline void WriteLittleEndianValue(void* p, V value) {
#if defined(V8_TARGET_LITTLE_ENDIAN)
WriteUnalignedValue<V>(p, value);
#elif defined(V8_TARGET_BIG_ENDIAN)
byte* src = reinterpret_cast<byte*>(&value);
byte* dst = reinterpret_cast<byte*>(p);
for (size_t i = 0; i < sizeof(V); i++) {
dst[i] = src[sizeof(V) - i - 1];
}
#endif // V8_TARGET_LITTLE_ENDIAN
}
// Represents a linked list that threads through the nodes in the linked list.
// Entries in the list are pointers to nodes. The nodes need to have a T**
// next() method that returns the location where the next value is stored.
template <typename T>
class ThreadedList final {
public:
ThreadedList() : head_(nullptr), tail_(&head_) {}
void Add(T* v) {
DCHECK_NULL(*tail_);
DCHECK_NULL(*v->next());
*tail_ = v;
tail_ = v->next();
}
void Clear() {
head_ = nullptr;
tail_ = &head_;
}
class Iterator final {
public:
Iterator& operator++() {
entry_ = (*entry_)->next();
return *this;
}
bool operator!=(const Iterator& other) { return entry_ != other.entry_; }
T* operator*() { return *entry_; }
Iterator& operator=(T* entry) {
T* next = *(*entry_)->next();
*entry->next() = next;
*entry_ = entry;
return *this;
}
private:
explicit Iterator(T** entry) : entry_(entry) {}
T** entry_;
friend class ThreadedList;
};
class ConstIterator final {
public:
ConstIterator& operator++() {
entry_ = (*entry_)->next();
return *this;
}
bool operator!=(const ConstIterator& other) {
return entry_ != other.entry_;
}
const T* operator*() const { return *entry_; }
private:
explicit ConstIterator(T* const* entry) : entry_(entry) {}
T* const* entry_;
friend class ThreadedList;
};
Iterator begin() { return Iterator(&head_); }
Iterator end() { return Iterator(tail_); }
ConstIterator begin() const { return ConstIterator(&head_); }
ConstIterator end() const { return ConstIterator(tail_); }
void Rewind(Iterator reset_point) {
tail_ = reset_point.entry_;
*tail_ = nullptr;
}
void MoveTail(ThreadedList<T>* parent, Iterator location) {
if (parent->end() != location) {
DCHECK_NULL(*tail_);
*tail_ = *location;
tail_ = parent->tail_;
parent->Rewind(location);
}
}
bool is_empty() const { return head_ == nullptr; }
// Slow. For testing purposes.
int LengthForTest() {
int result = 0;
for (Iterator t = begin(); t != end(); ++t) ++result;
return result;
}
T* AtForTest(int i) {
Iterator t = begin();
while (i-- > 0) ++t;
return *t;
}
private:
T* head_;
T** tail_;
DISALLOW_COPY_AND_ASSIGN(ThreadedList);
};
// Can be used to create a threaded list of |T|.
template <typename T>
class ThreadedListZoneEntry final : public ZoneObject {
public:
explicit ThreadedListZoneEntry(T value) : value_(value), next_(nullptr) {}
T value() { return value_; }
ThreadedListZoneEntry<T>** next() { return &next_; }
private:
T value_;
ThreadedListZoneEntry<T>* next_;
DISALLOW_COPY_AND_ASSIGN(ThreadedListZoneEntry);
};
} // namespace internal
} // namespace v8
#endif // V8_UTILS_H_