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