assembler/AssemblerBuffer.h

   1 /*
   2  * Copyright (C) 2008 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef AssemblerBuffer_h
  27 #define AssemblerBuffer_h
  28
  29 #if ENABLE(ASSEMBLER)
  30
  31 #include "stdint.h"
  32 #include <string.h>
  33 #include <jit/ExecutableAllocator.h>
  34 #include <wtf/Assertions.h>
  35 #include <wtf/FastMalloc.h>
  36
  37 namespace JSC {
  38
  39     class AssemblerBuffer {
  40         static const int inlineCapacity = 256;
  41     public:
  42         AssemblerBuffer()
  43             : m_buffer(m_inlineBuffer)
  44             , m_capacity(inlineCapacity)
  45             , m_size(0)
  46         {
  47         }
  48
  49         ~AssemblerBuffer()
  50         {
  51             if (m_buffer != m_inlineBuffer)
  52                 fastFree(m_buffer);
  53         }
  54
  55         void ensureSpace(int space)
  56         {
  57             if (m_size > m_capacity - space)
  58                 grow();
  59         }
  60
  61         bool isAligned(int alignment) const
  62         {
  63             return !(m_size & (alignment - 1));
  64         }
  65
  66         void putByteUnchecked(int value)
  67         {
  68             ASSERT(!(m_size > m_capacity - 4));
  69             m_buffer[m_size] = value;
  70             m_size++;
  71         }
  72
  73         void putByte(int value)
  74         {
  75             if (m_size > m_capacity - 4)
  76                 grow();
  77             putByteUnchecked(value);
  78         }
  79
  80         void putShortUnchecked(int value)
  81         {
  82             ASSERT(!(m_size > m_capacity - 4));
  83             *reinterpret_cast<short*>(&m_buffer[m_size]) = value;
  84             m_size += 2;
  85         }
  86
  87         void putShort(int value)
  88         {
  89             if (m_size > m_capacity - 4)
  90                 grow();
  91             putShortUnchecked(value);
  92         }
  93
  94         void putIntUnchecked(int value)
  95         {
  96             ASSERT(!(m_size > m_capacity - 4));
  97             *reinterpret_cast<int*>(&m_buffer[m_size]) = value;
  98             m_size += 4;
  99         }
 100
 101         void putInt64Unchecked(int64_t value)
 102         {
 103             ASSERT(!(m_size > m_capacity - 8));
 104             *reinterpret_cast<int64_t*>(&m_buffer[m_size]) = value;
 105             m_size += 8;
 106         }
 107
 108         void putInt(int value)
 109         {
 110             if (m_size > m_capacity - 4)
 111                 grow();
 112             putIntUnchecked(value);
 113         }
 114
 115         void* data() const
 116         {
 117             return m_buffer;
 118         }
 119
 120         int size() const
 121         {
 122             return m_size;
 123         }
 124
 125         void* executableCopy(ExecutablePool* allocator)
 126         {
 127             if (!m_size)
 128                 return 0;
 129
 130             void* result = allocator->alloc(m_size);
 131
 132             if (!result)
 133                 return 0;
 134
 135             ExecutableAllocator::makeWritable(result, m_size);
 136
 137             return memcpy(result, m_buffer, m_size);
 138         }
 139
 140     protected:
 141         void append(const char* data, int size)
 142         {
 143             if (m_size > m_capacity - size)
 144                 grow(size);
 145
 146             memcpy(m_buffer + m_size, data, size);
 147             m_size += size;
 148         }
 149
 150         void grow(int extraCapacity = 0)
 151         {
 152             m_capacity += m_capacity / 2 + extraCapacity;
 153
 154             if (m_buffer == m_inlineBuffer) {
 155                 char* newBuffer = static_cast<char*>(fastMalloc(m_capacity));
 156                 m_buffer = static_cast<char*>(memcpy(newBuffer, m_buffer, m_size));
 157             } else
 158                 m_buffer = static_cast<char*>(fastRealloc(m_buffer, m_capacity));
 159         }
 160
 161         char m_inlineBuffer[inlineCapacity];
 162         char* m_buffer;
 163         int m_capacity;
 164         int m_size;
 165     };
 166
 167 } // namespace JSC
 168
 169 #endif // ENABLE(ASSEMBLER)
 170
 171 #endif // AssemblerBuffer_h