heap/ConservativeRoots.cpp

   1 /*
   2  * Copyright (C) 2011 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. AND ITS CONTRIBUTORS ``AS IS''
  14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  23  * THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "ConservativeRoots.h"
  28
  29 namespace JSC {
  30
  31 inline bool isPointerAligned(void* p)
  32 {
  33     return !((intptr_t)(p) & (sizeof(char*) - 1));
  34 }
  35
  36 void ConservativeRoots::grow()
  37 {
  38     size_t newCapacity = m_capacity == inlineCapacity ? nonInlineCapacity : m_capacity * 2;
  39     JSCell** newRoots = static_cast<JSCell**>(OSAllocator::reserveAndCommit(newCapacity * sizeof(JSCell*)));
  40     memcpy(newRoots, m_roots, m_size * sizeof(JSCell*));
  41     if (m_roots != m_inlineRoots)
  42         OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(JSCell*));
  43     m_capacity = newCapacity;
  44     m_roots = newRoots;
  45 }
  46
  47 void ConservativeRoots::add(void* begin, void* end)
  48 {
  49     ASSERT(begin <= end);
  50     ASSERT((static_cast<char*>(end) - static_cast<char*>(begin)) < 0x1000000);
  51     ASSERT(isPointerAligned(begin));
  52     ASSERT(isPointerAligned(end));
  53
  54     for (char** it = static_cast<char**>(begin); it != static_cast<char**>(end); ++it)
  55         add(*it);
  56 }
  57
  58 } // namespace JSC