Line data    Source code

       1             : // Copyright 2011 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #ifndef V8_V8MEMORY_H_
       6             : #define V8_V8MEMORY_H_
       7             : 
       8             : #include "src/globals.h"
       9             : 
      10             : namespace v8 {
      11             : namespace internal {
      12             : 
      13             : // Memory provides an interface to 'raw' memory. It encapsulates the casts
      14             : // that typically are needed when incompatible pointer types are used.
      15             : // Note that this class currently relies on undefined behaviour. There is a
      16             : // proposal (http://wg21.link/p0593r2) to make it defined behaviour though.
      17             : template <class T>
      18    27536275 : T& Memory(Address addr) {
      19   419935295 :   return *reinterpret_cast<T*>(addr);
      20             : }
      21             : template <class T>
      22             : T& Memory(byte* addr) {
      23             :   return Memory<T>(reinterpret_cast<Address>(addr));
      24             : }
      25             : 
      26             : template <typename V>
      27             : static inline V ReadUnalignedValue(Address p) {
      28             :   ASSERT_TRIVIALLY_COPYABLE(V);
      29             : #if !(V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM)
      30   196478472 :   return *reinterpret_cast<const V*>(p);
      31             : #else   // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM
      32             :   V r;
      33             :   memmove(&r, reinterpret_cast<void*>(p), sizeof(V));
      34             :   return r;
      35             : #endif  // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM
      36             : }
      37             : 
      38             : template <typename V>
      39             : static inline void WriteUnalignedValue(Address p, V value) {
      40             :   ASSERT_TRIVIALLY_COPYABLE(V);
      41             : #if !(V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM)
      42    49756812 :   *(reinterpret_cast<V*>(p)) = value;
      43             : #else   // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM
      44             :   memmove(reinterpret_cast<void*>(p), &value, sizeof(V));
      45             : #endif  // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM
      46             : }
      47             : 
      48             : static inline double ReadFloatValue(Address p) {
      49             :   return ReadUnalignedValue<float>(p);
      50             : }
      51             : 
      52             : static inline double ReadDoubleValue(Address p) {
      53             :   return ReadUnalignedValue<double>(p);
      54             : }
      55             : 
      56             : static inline void WriteDoubleValue(Address p, double value) {
      57             :   WriteUnalignedValue(p, value);
      58             : }
      59             : 
      60             : static inline uint16_t ReadUnalignedUInt16(Address p) {
      61             :   return ReadUnalignedValue<uint16_t>(p);
      62             : }
      63             : 
      64             : static inline void WriteUnalignedUInt16(Address p, uint16_t value) {
      65             :   WriteUnalignedValue(p, value);
      66             : }
      67             : 
      68             : static inline uint32_t ReadUnalignedUInt32(Address p) {
      69             :   return ReadUnalignedValue<uint32_t>(p);
      70             : }
      71             : 
      72             : static inline void WriteUnalignedUInt32(Address p, uint32_t value) {
      73             :   WriteUnalignedValue(p, value);
      74             : }
      75             : 
      76             : template <typename V>
      77             : static inline V ReadLittleEndianValue(Address p) {
      78             : #if defined(V8_TARGET_LITTLE_ENDIAN)
      79             :   return ReadUnalignedValue<V>(p);
      80             : #elif defined(V8_TARGET_BIG_ENDIAN)
      81             :   V ret{};
      82             :   const byte* src = reinterpret_cast<const byte*>(p);
      83             :   byte* dst = reinterpret_cast<byte*>(&ret);
      84             :   for (size_t i = 0; i < sizeof(V); i++) {
      85             :     dst[i] = src[sizeof(V) - i - 1];
      86             :   }
      87             :   return ret;
      88             : #endif  // V8_TARGET_LITTLE_ENDIAN
      89             : }
      90             : 
      91             : template <typename V>
      92             : static inline void WriteLittleEndianValue(Address p, V value) {
      93             : #if defined(V8_TARGET_LITTLE_ENDIAN)
      94             :   WriteUnalignedValue<V>(p, value);
      95             : #elif defined(V8_TARGET_BIG_ENDIAN)
      96             :   byte* src = reinterpret_cast<byte*>(&value);
      97             :   byte* dst = reinterpret_cast<byte*>(p);
      98             :   for (size_t i = 0; i < sizeof(V); i++) {
      99             :     dst[i] = src[sizeof(V) - i - 1];
     100             :   }
     101             : #endif  // V8_TARGET_LITTLE_ENDIAN
     102             : }
     103             : 
     104             : template <typename V>
     105             : static inline V ReadLittleEndianValue(V* p) {
     106             :   return ReadLittleEndianValue<V>(reinterpret_cast<Address>(p));
     107             : }
     108             : 
     109             : template <typename V>
     110             : static inline void WriteLittleEndianValue(V* p, V value) {
     111             :   WriteLittleEndianValue<V>(reinterpret_cast<Address>(p), value);
     112             : }
     113             : 
     114             : }  // namespace internal
     115             : }  // namespace v8
     116             : 
     117             : #endif  // V8_V8MEMORY_H_