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// Copyright 2011 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_V8MEMORY_H_
#define V8_V8MEMORY_H_
#include "src/globals.h"
namespace v8 {
namespace internal {
// Memory provides an interface to 'raw' memory. It encapsulates the casts
// that typically are needed when incompatible pointer types are used.
// Note that this class currently relies on undefined behaviour. There is a
// proposal (http://wg21.link/p0593r2) to make it defined behaviour though.
class Memory {
public:
static uint8_t& uint8_at(Address addr) {
return *reinterpret_cast<uint8_t*>(addr);
}
static uint16_t& uint16_at(Address addr) {
return *reinterpret_cast<uint16_t*>(addr);
}
static uint32_t& uint32_at(Address addr) {
return *reinterpret_cast<uint32_t*>(addr);
}
static int32_t& int32_at(Address addr) {
return *reinterpret_cast<int32_t*>(addr);
}
static uint64_t& uint64_at(Address addr) {
return *reinterpret_cast<uint64_t*>(addr);
}
static int64_t& int64_at(Address addr) {
return *reinterpret_cast<int64_t*>(addr);
}
static int& int_at(Address addr) {
return *reinterpret_cast<int*>(addr);
}
static unsigned& unsigned_at(Address addr) {
return *reinterpret_cast<unsigned*>(addr);
}
static intptr_t& intptr_at(Address addr) {
return *reinterpret_cast<intptr_t*>(addr);
}
static uintptr_t& uintptr_at(Address addr) {
return *reinterpret_cast<uintptr_t*>(addr);
}
static float& float_at(Address addr) {
return *reinterpret_cast<float*>(addr);
}
static double& double_at(Address addr) {
return *reinterpret_cast<double*>(addr);
}
static Address& Address_at(Address addr) {
return *reinterpret_cast<Address*>(addr);
}
static Object*& Object_at(Address addr) {
return *reinterpret_cast<Object**>(addr);
}
static Handle<Object>& Object_Handle_at(Address addr) {
return *reinterpret_cast<Handle<Object>*>(addr);
}
static bool IsAddressInRange(Address base, Address address, uint32_t size) {
return base <= address && address < base + size;
}
};
template <typename V>
static inline V ReadUnalignedValue(Address p) {
ASSERT_TRIVIALLY_COPYABLE(V);
#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, reinterpret_cast<void*>(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(Address p, V value) {
ASSERT_TRIVIALLY_COPYABLE(V);
#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(reinterpret_cast<void*>(p), &value, sizeof(V));
#endif // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM
}
static inline double ReadFloatValue(Address p) {
return ReadUnalignedValue<float>(p);
}
static inline double ReadDoubleValue(Address p) {
return ReadUnalignedValue<double>(p);
}
static inline void WriteDoubleValue(Address p, double value) {
WriteUnalignedValue(p, value);
}
static inline uint16_t ReadUnalignedUInt16(Address p) {
return ReadUnalignedValue<uint16_t>(p);
}
static inline void WriteUnalignedUInt16(Address p, uint16_t value) {
WriteUnalignedValue(p, value);
}
static inline uint32_t ReadUnalignedUInt32(Address p) {
return ReadUnalignedValue<uint32_t>(p);
}
static inline void WriteUnalignedUInt32(Address p, uint32_t value) {
WriteUnalignedValue(p, value);
}
template <typename V>
static inline V ReadLittleEndianValue(Address p) {
#if defined(V8_TARGET_LITTLE_ENDIAN)
return ReadUnalignedValue<V>(p);
#elif defined(V8_TARGET_BIG_ENDIAN)
V ret{};
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(Address 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
}
template <typename V>
static inline V ReadLittleEndianValue(V* p) {
return ReadLittleEndianValue<V>(reinterpret_cast<Address>(p));
}
template <typename V>
static inline void WriteLittleEndianValue(V* p, V value) {
WriteLittleEndianValue<V>(reinterpret_cast<Address>(p), value);
}
} // namespace internal
} // namespace v8
#endif // V8_V8MEMORY_H_