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// 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_UTILS_H_
#define V8_UTILS_UTILS_H_
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <cmath>
#include <string>
#include <type_traits>
#include "include/v8.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/base/v8-fallthrough.h"
#include "src/common/globals.h"
#include "src/utils/allocation.h"
#include "src/utils/vector.h"
#if defined(V8_USE_SIPHASH)
#include "src/third_party/siphash/halfsiphash.h"
#endif
#if defined(V8_OS_AIX)
#include <fenv.h> // NOLINT(build/c++11)
#endif
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; }
// Checks if value is in range [lower_limit, higher_limit] using a single
// branch.
template <typename T, typename U>
inline constexpr bool IsInRange(T value, U lower_limit, U higher_limit) {
#if V8_CAN_HAVE_DCHECK_IN_CONSTEXPR
DCHECK(lower_limit <= higher_limit);
#endif
STATIC_ASSERT(sizeof(U) <= sizeof(T));
using unsigned_T = typename std::make_unsigned<T>::type;
// Use static_cast to support enum classes.
return static_cast<unsigned_T>(static_cast<unsigned_T>(value) -
static_cast<unsigned_T>(lower_limit)) <=
static_cast<unsigned_T>(static_cast<unsigned_T>(higher_limit) -
static_cast<unsigned_T>(lower_limit));
}
// Checks if [index, index+length) is in range [0, max). Note that this check
// works even if {index+length} would wrap around.
inline constexpr bool IsInBounds(size_t index, size_t length, size_t max) {
return length <= max && index <= (max - length);
}
// Checks if [index, index+length) is in range [0, max). If not, {length} is
// clamped to its valid range. Note that this check works even if
// {index+length} would wrap around.
template <typename T>
inline bool ClampToBounds(T index, T* length, T max) {
if (index > max) {
*length = 0;
return false;
}
T avail = max - index;
bool oob = *length > avail;
if (oob) *length = avail;
return !oob;
}
// X must be a power of 2. Returns the number of trailing zeros.
template <typename T,
typename = typename std::enable_if<std::is_integral<T>::value>::type>
inline int WhichPowerOf2(T x) {
DCHECK(base::bits::IsPowerOfTwo(x));
int bits = 0;
#ifdef DEBUG
const T original_x = x;
#endif
constexpr int max_bits = sizeof(T) * 8;
static_assert(max_bits <= 64, "integral types are not bigger than 64 bits");
// Avoid shifting by more than the bit width of x to avoid compiler warnings.
#define CHECK_BIGGER(s) \
if (max_bits > s && x >= T{1} << (max_bits > s ? s : 0)) { \
bits += s; \
x >>= max_bits > s ? s : 0; \
}
CHECK_BIGGER(32)
CHECK_BIGGER(16)
CHECK_BIGGER(8)
CHECK_BIGGER(4)
#undef CHECK_BIGGER
switch (x) {
default:
UNREACHABLE();
case 8:
bits++;
V8_FALLTHROUGH;
case 4:
bits++;
V8_FALLTHROUGH;
case 2:
bits++;
V8_FALLTHROUGH;
case 1:
break;
}
DCHECK_EQ(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;
}
// 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));
}
// Returns the maximum of the two parameters.
template <typename T>
constexpr T Max(T a, T b) {
return a < b ? b : a;
}
// Returns the minimum of the two parameters.
template <typename T>
constexpr 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,
typename = typename std::enable_if<std::is_signed<T>::value>::type>
typename std::make_unsigned<T>::type Abs(T a) {
// This is a branch-free implementation of the absolute value function and is
// described in Warren's "Hacker's Delight", chapter 2. It avoids undefined
// behavior with the arithmetic negation operation on signed values as well.
using unsignedT = typename std::make_unsigned<T>::type;
unsignedT x = static_cast<unsignedT>(a);
unsignedT y = static_cast<unsignedT>(a >> (sizeof(T) * 8 - 1));
return (x ^ y) - y;
}
// Returns the negative absolute value of its argument.
template <typename T,
typename = typename std::enable_if<std::is_signed<T>::value>::type>
T Nabs(T a) {
return a < 0 ? a : -a;
}
inline double Modulo(double x, double y) {
#if defined(V8_OS_WIN)
// Workaround MS fmod bugs. ECMA-262 says:
// dividend is finite and divisor is an infinity => result equals dividend
// dividend is a zero and divisor is nonzero finite => result equals dividend
if (!(std::isfinite(x) && (!std::isfinite(y) && !std::isnan(y))) &&
!(x == 0 && (y != 0 && std::isfinite(y)))) {
double result = fmod(x, y);
// Workaround MS bug in VS CRT in some OS versions, https://crbug.com/915045
// fmod(-17, +/-1) should equal -0.0 but now returns 0.0.
if (x < 0 && result == 0) result = -0.0;
x = result;
}
return x;
#elif defined(V8_OS_AIX)
// AIX raises an underflow exception for (Number.MIN_VALUE % Number.MAX_VALUE)
feclearexcept(FE_ALL_EXCEPT);
double result = std::fmod(x, y);
int exception = fetestexcept(FE_UNDERFLOW);
return (exception ? x : result);
#else
return std::fmod(x, y);
#endif
}
template <typename T>
T SaturateAdd(T a, T b) {
if (std::is_signed<T>::value) {
if (a > 0 && b > 0) {
if (a > std::numeric_limits<T>::max() - b) {
return std::numeric_limits<T>::max();
}
} else if (a < 0 && b < 0) {
if (a < std::numeric_limits<T>::min() - b) {
return std::numeric_limits<T>::min();
}
}
} else {
CHECK(std::is_unsigned<T>::value);
if (a > std::numeric_limits<T>::max() - b) {
return std::numeric_limits<T>::max();
}
}
return a + b;
}
template <typename T>
T SaturateSub(T a, T b) {
if (std::is_signed<T>::value) {
if (a >= 0 && b < 0) {
if (a > std::numeric_limits<T>::max() + b) {
return std::numeric_limits<T>::max();
}
} else if (a < 0 && b > 0) {
if (a < std::numeric_limits<T>::min() + b) {
return std::numeric_limits<T>::min();
}
}
} else {
CHECK(std::is_unsigned<T>::value);
if (a < b) {
return static_cast<T>(0);
}
}
return a - b;
}
// ----------------------------------------------------------------------------
// BitField is a help template for encoding and decode bitfield with
// unsigned content.
// Instantiate them via 'using', which is cheaper than deriving a new class:
// using MyBitField = BitField<int, 4, 2, MyEnum>;
// The BitField class is final to enforce this style over derivation.
template <class T, int shift, int size, class U = uint32_t>
class BitField final {
public:
STATIC_ASSERT(std::is_unsigned<U>::value);
STATIC_ASSERT(shift < 8 * sizeof(U)); // Otherwise shifts by {shift} are UB.
STATIC_ASSERT(size < 8 * sizeof(U)); // Otherwise shifts by {size} are UB.
STATIC_ASSERT(shift + size <= 8 * sizeof(U));
STATIC_ASSERT(size > 0);
using FieldType = T;
// 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 constexpr int kShift = shift;
static constexpr int kSize = size;
static constexpr U kMask = ((U{1} << kShift) << kSize) - (U{1} << kShift);
static constexpr int kLastUsedBit = kShift + kSize - 1;
static constexpr U kNumValues = U{1} << kSize;
// Value for the field with all bits set.
static constexpr T kMax = static_cast<T>(kNumValues - 1);
template <class T2, int size2>
using Next = BitField<T2, kShift + kSize, size2, U>;
// Tells whether the provided value fits into the bit field.
static constexpr 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 constexpr U encode(T value) {
#if V8_CAN_HAVE_DCHECK_IN_CONSTEXPR
DCHECK(is_valid(value));
#endif
return static_cast<U>(value) << kShift;
}
// Returns a type U with the bit field value updated.
static constexpr U update(U previous, T value) {
return (previous & ~kMask) | encode(value);
}
// Extracts the bit field from the value.
static constexpr T decode(U value) {
return static_cast<T>((value & kMask) >> kShift);
}
};
template <class T, int shift, int size>
using BitField8 = BitField<T, shift, size, uint8_t>;
template <class T, int shift, int size>
using BitField16 = BitField<T, shift, size, uint16_t>;
template <class T, int shift, int size>
using BitField64 = BitField<T, shift, size, uint64_t>;
// Helper macros for defining a contiguous sequence of bit fields. Example:
// (backslashes at the ends of respective lines of this multi-line macro
// definition are omitted here to please the compiler)
//
// #define MAP_BIT_FIELD1(V, _)
// V(IsAbcBit, bool, 1, _)
// V(IsBcdBit, bool, 1, _)
// V(CdeBits, int, 5, _)
// V(DefBits, MutableMode, 1, _)
//
// DEFINE_BIT_FIELDS(MAP_BIT_FIELD1)
// or
// DEFINE_BIT_FIELDS_64(MAP_BIT_FIELD1)
//
#define DEFINE_BIT_FIELD_RANGE_TYPE(Name, Type, Size, _) \
k##Name##Start, k##Name##End = k##Name##Start + Size - 1,
#define DEFINE_BIT_RANGES(LIST_MACRO) \
struct LIST_MACRO##_Ranges { \
enum { LIST_MACRO(DEFINE_BIT_FIELD_RANGE_TYPE, _) kBitsCount }; \
};
#define DEFINE_BIT_FIELD_TYPE(Name, Type, Size, RangesName) \
using Name = BitField<Type, RangesName::k##Name##Start, Size>;
#define DEFINE_BIT_FIELD_64_TYPE(Name, Type, Size, RangesName) \
using Name = BitField64<Type, RangesName::k##Name##Start, Size>;
#define DEFINE_BIT_FIELDS(LIST_MACRO) \
DEFINE_BIT_RANGES(LIST_MACRO) \
LIST_MACRO(DEFINE_BIT_FIELD_TYPE, LIST_MACRO##_Ranges)
#define DEFINE_BIT_FIELDS_64(LIST_MACRO) \
DEFINE_BIT_RANGES(LIST_MACRO) \
LIST_MACRO(DEFINE_BIT_FIELD_64_TYPE, LIST_MACRO##_Ranges)
// ----------------------------------------------------------------------------
// 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:
// using BoolComputer = BitSetComputer<bool, 1, kSmiValueSize, uint32_t>;
//
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; }
};
// Helper macros for defining a contiguous sequence of field offset constants.
// Example: (backslashes at the ends of respective lines of this multi-line
// macro definition are omitted here to please the compiler)
//
// #define MAP_FIELDS(V)
// V(kField1Offset, kTaggedSize)
// V(kField2Offset, kIntSize)
// V(kField3Offset, kIntSize)
// V(kField4Offset, kSystemPointerSize)
// V(kSize, 0)
//
// DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, MAP_FIELDS)
//
#define DEFINE_ONE_FIELD_OFFSET(Name, Size) Name, Name##End = Name + (Size)-1,
#define DEFINE_FIELD_OFFSET_CONSTANTS(StartOffset, LIST_MACRO) \
enum { \
LIST_MACRO##_StartOffset = StartOffset - 1, \
LIST_MACRO(DEFINE_ONE_FIELD_OFFSET) \
};
// Size of the field defined by DEFINE_FIELD_OFFSET_CONSTANTS
#define FIELD_SIZE(Name) (Name##End + 1 - Name)
// Compare two offsets with static cast
#define STATIC_ASSERT_FIELD_OFFSETS_EQUAL(Offset1, Offset2) \
STATIC_ASSERT(static_cast<int>(Offset1) == Offset2)
// ----------------------------------------------------------------------------
// Hash function.
static const uint64_t kZeroHashSeed = 0;
// Thomas Wang, Integer Hash Functions.
// http://www.concentric.net/~Ttwang/tech/inthash.htm`
inline uint32_t ComputeUnseededHash(uint32_t key) {
uint32_t hash = key;
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 & 0x3fffffff);
}
inline uint32_t ComputeSeededHash(uint32_t key, uint64_t seed) {
#ifdef V8_USE_SIPHASH
return halfsiphash(key, seed);
#else
return ComputeLongHash(static_cast<uint64_t>(key) ^ seed);
#endif // V8_USE_SIPHASH
}
inline uint32_t ComputePointerHash(void* ptr) {
return ComputeUnseededHash(
static_cast<uint32_t>(reinterpret_cast<intptr_t>(ptr)));
}
inline uint32_t ComputeAddressHash(Address address) {
return ComputeUnseededHash(static_cast<uint32_t>(address & 0xFFFFFFFFul));
}
// ----------------------------------------------------------------------------
// 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_ = nullptr;
instance_ = nullptr;
}
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() = default;
bool is_set() const { return pointer_ != nullptr; }
T* get() const {
DCHECK_NOT_NULL(pointer_);
return pointer_;
}
void set(T* value) {
DCHECK(pointer_ == nullptr && value != nullptr);
pointer_ = value;
}
SetOncePointer& operator=(T* value) {
set(value);
return *this;
}
bool operator==(std::nullptr_t) const { return pointer_ == nullptr; }
bool operator!=(std::nullptr_t) const { return pointer_ != nullptr; }
private:
T* pointer_ = nullptr;
};
// 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_LE(sizeof(lchar), 2);
DCHECK_LE(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_LE(exponent, 9);
DCHECK_GE(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_NE(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);
};
// 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));
}
// clang-format off
#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)
// clang-format on
#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
// clang-format off
#define INT_0_TO_127_LIST(V) \
V(0) 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) V(64) V(65) V(66) V(67) V(68) V(69) \
V(70) V(71) V(72) V(73) V(74) V(75) V(76) V(77) V(78) V(79) \
V(80) V(81) V(82) V(83) V(84) V(85) V(86) V(87) V(88) V(89) \
V(90) V(91) V(92) V(93) V(94) V(95) V(96) V(97) V(98) V(99) \
V(100) V(101) V(102) V(103) V(104) V(105) V(106) V(107) V(108) V(109) \
V(110) V(111) V(112) V(113) V(114) V(115) V(116) V(117) V(118) V(119) \
V(120) V(121) V(122) V(123) V(124) V(125) V(126) V(127)
// clang-format on
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(); }
V8_EXPORT_PRIVATE friend std::ostream& operator<<(std::ostream& os,
FeedbackSlot);
private:
static const int kInvalidSlot = -1;
int id_;
};
V8_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os, FeedbackSlot);
class BailoutId {
public:
explicit BailoutId(int id) : id_(id) {}
int ToInt() const { return id_; }
static BailoutId None() { return BailoutId(kNoneId); }
// 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:
friend class Builtins;
static const int kNoneId = -1;
// Using 0 could disguise errors.
// Builtin continuations bailout ids start here. If you need to add a
// non-builtin BailoutId, add it before this id so that this Id has the
// highest number.
static const int kFirstBuiltinContinuationId = 1;
int id_;
};
// ----------------------------------------------------------------------------
// I/O support.
// Our version of printf().
V8_EXPORT_PRIVATE void PRINTF_FORMAT(1, 2) PrintF(const char* format, ...);
V8_EXPORT_PRIVATE 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.
V8_EXPORT_PRIVATE int PRINTF_FORMAT(2, 3)
SNPrintF(Vector<char> str, const char* format, ...);
V8_EXPORT_PRIVATE 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);
// 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);
// Simple support to read a file into std::string.
// On return, *exits tells whether the file existed.
V8_EXPORT_PRIVATE std::string ReadFile(const char* filename, bool* exists,
bool verbose = true);
V8_EXPORT_PRIVATE std::string ReadFile(FILE* file, bool* exists,
bool verbose = true);
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 Char>
bool TryAddIndexChar(uint32_t* index, Char c);
template <typename Stream>
bool StringToArrayIndex(Stream* stream, uint32_t* index);
// Returns the current stack top. Works correctly with ASAN and SafeStack.
// GetCurrentStackPosition() should not be inlined, because it works on stack
// frames if it were inlined into a function with a huge stack frame it would
// return an address significantly above the actual current stack position.
V8_EXPORT_PRIVATE V8_NOINLINE uintptr_t GetCurrentStackPosition();
static inline uint16_t ByteReverse16(uint16_t value) {
#if V8_HAS_BUILTIN_BSWAP16
return __builtin_bswap16(value);
#else
return value << 8 | (value >> 8 & 0x00FF);
#endif
}
static inline uint32_t ByteReverse32(uint32_t value) {
#if V8_HAS_BUILTIN_BSWAP32
return __builtin_bswap32(value);
#else
return value << 24 | ((value << 8) & 0x00FF0000) |
((value >> 8) & 0x0000FF00) | ((value >> 24) & 0x00000FF);
#endif
}
static inline uint64_t ByteReverse64(uint64_t value) {
#if V8_HAS_BUILTIN_BSWAP64
return __builtin_bswap64(value);
#else
size_t bits_of_v = sizeof(value) * kBitsPerByte;
return value << (bits_of_v - 8) |
((value << (bits_of_v - 24)) & 0x00FF000000000000) |
((value << (bits_of_v - 40)) & 0x0000FF0000000000) |
((value << (bits_of_v - 56)) & 0x000000FF00000000) |
((value >> (bits_of_v - 56)) & 0x00000000FF000000) |
((value >> (bits_of_v - 40)) & 0x0000000000FF0000) |
((value >> (bits_of_v - 24)) & 0x000000000000FF00) |
((value >> (bits_of_v - 8)) & 0x00000000000000FF);
#endif
}
template <typename V>
static inline V ByteReverse(V value) {
size_t size_of_v = sizeof(value);
switch (size_of_v) {
case 1:
return value;
case 2:
return static_cast<V>(ByteReverse16(static_cast<uint16_t>(value)));
case 4:
return static_cast<V>(ByteReverse32(static_cast<uint32_t>(value)));
case 8:
return static_cast<V>(ByteReverse64(static_cast<uint64_t>(value)));
default:
UNREACHABLE();
}
}
V8_EXPORT_PRIVATE bool PassesFilter(Vector<const char> name,
Vector<const char> filter);
// Zap the specified area with a specific byte pattern. This currently defaults
// to int3 on x64 and ia32. On other architectures this will produce unspecified
// instruction sequences.
// TODO(jgruber): Better support for other architectures.
V8_INLINE void ZapCode(Address addr, size_t size_in_bytes) {
static constexpr int kZapByte = 0xCC;
std::memset(reinterpret_cast<void*>(addr), kZapByte, size_in_bytes);
}
} // namespace internal
} // namespace v8
#endif // V8_UTILS_UTILS_H_