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 #include <wtf/StdLibExtras.h>
  37
  38 namespace JSC {
  39
  40     struct AssemblerLabel {
  41         AssemblerLabel()
  42             : m_offset(std::numeric_limits<uint32_t>::max())
  43         {
  44         }
  45
  46         explicit AssemblerLabel(uint32_t offset)
  47             : m_offset(offset)
  48         {
  49         }
  50
  51         bool isSet() const { return (m_offset != std::numeric_limits<uint32_t>::max()); }
  52
  53         AssemblerLabel labelAtOffset(int offset) const
  54         {
  55             return AssemblerLabel(m_offset + offset);
  56         }
  57
  58         uint32_t m_offset;
  59     };
  60
  61     class AssemblerBuffer {
  62         static const int inlineCapacity = 128;
  63     public:
  64         AssemblerBuffer()
  65             : m_storage(inlineCapacity)
  66             , m_buffer(m_storage.begin())
  67             , m_capacity(inlineCapacity)
  68             , m_index(0)
  69         {
  70         }
  71
  72         ~AssemblerBuffer()
  73         {
  74         }
  75
  76         bool isAvailable(int space)
  77         {
  78             return m_index + space <= m_capacity;
  79         }
  80
  81         void ensureSpace(int space)
  82         {
  83             if (!isAvailable(space))
  84                 grow();
  85         }
  86
  87         bool isAligned(int alignment) const
  88         {
  89             return !(m_index & (alignment - 1));
  90         }
  91
  92         template<typename IntegralType>
  93         void putIntegral(IntegralType value)
  94         {
  95             ensureSpace(sizeof(IntegralType));
  96             putIntegralUnchecked(value);
  97         }
  98
  99         template<typename IntegralType>
 100         void putIntegralUnchecked(IntegralType value)
 101         {
 102             ASSERT(isAvailable(sizeof(IntegralType)));
 103             *reinterpret_cast_ptr<IntegralType*>(m_buffer + m_index) = value;
 104             m_index += sizeof(IntegralType);
 105         }
 106
 107         void putByteUnchecked(int8_t value) { putIntegralUnchecked(value); }
 108         void putByte(int8_t value) { putIntegral(value); }
 109         void putShortUnchecked(int16_t value) { putIntegralUnchecked(value); }
 110         void putShort(int16_t value) { putIntegral(value); }
 111         void putIntUnchecked(int32_t value) { putIntegralUnchecked(value); }
 112         void putInt(int32_t value) { putIntegral(value); }
 113         void putInt64Unchecked(int64_t value) { putIntegralUnchecked(value); }
 114         void putInt64(int64_t value) { putIntegral(value); }
 115
 116         void* data() const
 117         {
 118             return m_buffer;
 119         }
 120
 121         size_t codeSize() const
 122         {
 123             return m_index;
 124         }
 125
 126         AssemblerLabel label() const
 127         {
 128             return AssemblerLabel(m_index);
 129         }
 130
 131         void* executableCopy(JSGlobalData& globalData, ExecutablePool* allocator)
 132         {
 133             if (!m_index)
 134                 return 0;
 135
 136             void* result = allocator->alloc(globalData, m_index);
 137
 138             if (!result)
 139                 return 0;
 140
 141             ExecutableAllocator::makeWritable(result, m_index);
 142
 143             return memcpy(result, m_buffer, m_index);
 144         }
 145
 146         void rewindToLabel(AssemblerLabel label)
 147         {
 148             m_index = label.m_offset;
 149         }
 150
 151 #ifndef NDEBUG
 152         unsigned debugOffset() { return m_index; }
 153 #endif
 154
 155     protected:
 156         void append(const char* data, int size)
 157         {
 158             if (!isAvailable(size))
 159                 grow(size);
 160
 161             memcpy(m_buffer + m_index, data, size);
 162             m_index += size;
 163         }
 164
 165         void grow(int extraCapacity = 0)
 166         {
 167             m_capacity += m_capacity / 2 + extraCapacity;
 168
 169             m_storage.grow(m_capacity);
 170             m_buffer = m_storage.begin();
 171         }
 172
 173     private:
 174         Vector<char, inlineCapacity> m_storage;
 175         char* m_buffer;
 176         int m_capacity;
 177         int m_index;
 178     };
 179
 180 } // namespace JSC
 181
 182 #endif // ENABLE(ASSEMBLER)
 183
 184 #endif // AssemblerBuffer_h