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             : T& Memory(Address addr) {
      19             :   // {addr} must be aligned.
      20             :   DCHECK_EQ(0, addr & (alignof(T) - 1));
      21   402165741 :   return *reinterpret_cast<T*>(addr);
      22             : }
      23             : template <class T>
      24             : T& Memory(byte* addr) {
      25             :   return Memory<T>(reinterpret_cast<Address>(addr));
      26             : }
      27             : 
      28             : template <typename V>
      29     1748725 : static inline V ReadUnalignedValue(Address p) {
      30             :   ASSERT_TRIVIALLY_COPYABLE(V);
      31             :   V r;
      32    60404303 :   memcpy(&r, reinterpret_cast<void*>(p), sizeof(V));
      33    10428048 :   return r;
      34             : }
      35             : 
      36             : template <typename V>
      37             : static inline void WriteUnalignedValue(Address p, V value) {
      38             :   ASSERT_TRIVIALLY_COPYABLE(V);
      39   144051248 :   memcpy(reinterpret_cast<void*>(p), &value, sizeof(V));
      40             : }
      41             : 
      42             : static inline double ReadFloatValue(Address p) {
      43             :   return ReadUnalignedValue<float>(p);
      44             : }
      45             : 
      46             : static inline double ReadDoubleValue(Address p) {
      47             :   return ReadUnalignedValue<double>(p);
      48             : }
      49             : 
      50             : static inline void WriteDoubleValue(Address p, double value) {
      51             :   WriteUnalignedValue(p, value);
      52             : }
      53             : 
      54             : static inline uint16_t ReadUnalignedUInt16(Address p) {
      55             :   return ReadUnalignedValue<uint16_t>(p);
      56             : }
      57             : 
      58             : static inline void WriteUnalignedUInt16(Address p, uint16_t value) {
      59             :   WriteUnalignedValue(p, value);
      60             : }
      61             : 
      62             : static inline uint32_t ReadUnalignedUInt32(Address p) {
      63             :   return ReadUnalignedValue<uint32_t>(p);
      64             : }
      65             : 
      66             : static inline void WriteUnalignedUInt32(Address p, uint32_t value) {
      67             :   WriteUnalignedValue(p, value);
      68             : }
      69             : 
      70             : template <typename V>
      71       16048 : static inline V ReadLittleEndianValue(Address p) {
      72             : #if defined(V8_TARGET_LITTLE_ENDIAN)
      73       16048 :   return ReadUnalignedValue<V>(p);
      74             : #elif defined(V8_TARGET_BIG_ENDIAN)
      75             :   V ret{};
      76             :   const byte* src = reinterpret_cast<const byte*>(p);
      77             :   byte* dst = reinterpret_cast<byte*>(&ret);
      78             :   for (size_t i = 0; i < sizeof(V); i++) {
      79             :     dst[i] = src[sizeof(V) - i - 1];
      80             :   }
      81             :   return ret;
      82             : #endif  // V8_TARGET_LITTLE_ENDIAN
      83             : }
      84             : 
      85             : template <typename V>
      86             : static inline void WriteLittleEndianValue(Address p, V value) {
      87             : #if defined(V8_TARGET_LITTLE_ENDIAN)
      88             :   WriteUnalignedValue<V>(p, value);
      89             : #elif defined(V8_TARGET_BIG_ENDIAN)
      90             :   byte* src = reinterpret_cast<byte*>(&value);
      91             :   byte* dst = reinterpret_cast<byte*>(p);
      92             :   for (size_t i = 0; i < sizeof(V); i++) {
      93             :     dst[i] = src[sizeof(V) - i - 1];
      94             :   }
      95             : #endif  // V8_TARGET_LITTLE_ENDIAN
      96             : }
      97             : 
      98             : template <typename V>
      99             : static inline V ReadLittleEndianValue(V* p) {
     100             :   return ReadLittleEndianValue<V>(reinterpret_cast<Address>(p));
     101             : }
     102             : 
     103             : template <typename V>
     104             : static inline void WriteLittleEndianValue(V* p, V value) {
     105             :   WriteLittleEndianValue<V>(reinterpret_cast<Address>(p), value);
     106             : }
     107             : 
     108             : }  // namespace internal
     109             : }  // namespace v8
     110             : 
     111             : #endif  // V8_V8MEMORY_H_