runtime/ArgList.cpp

   1 /*
   2  *  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2009 Apple Inc. All rights reserved.
   3  *
   4  *  This library is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU Library General Public
   6  *  License as published by the Free Software Foundation; either
   7  *  version 2 of the License, or (at your option) any later version.
   8  *
   9  *  This library is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *  Library General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU Library General Public License
  15  *  along with this library; see the file COPYING.LIB.  If not, write to
  16  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  *  Boston, MA 02110-1301, USA.
  18  *
  19  */
  20
  21 #include "config.h"
  22 #include "ArgList.h"
  23
  24 #include "JSValue.h"
  25 #include "JSCell.h"
  26 #include "JSObject.h"
  27 #include "ScopeChain.h"
  28
  29 using std::min;
  30
  31 namespace JSC {
  32
  33 void ArgList::getSlice(int startIndex, ArgList& result) const
  34 {
  35     if (startIndex <= 0 || static_cast<unsigned>(startIndex) >= m_argCount) {
  36         result = ArgList(m_args, 0);
  37         return;
  38     }
  39     result = ArgList(m_args + startIndex, m_argCount - startIndex);
  40 }
  41
  42 void MarkedArgumentBuffer::markLists(HeapRootVisitor& heapRootMarker, ListSet& markSet)
  43 {
  44     ListSet::iterator end = markSet.end();
  45     for (ListSet::iterator it = markSet.begin(); it != end; ++it) {
  46         MarkedArgumentBuffer* list = *it;
  47         heapRootMarker.mark(reinterpret_cast<JSValue*>(list->m_buffer), list->m_size);
  48     }
  49 }
  50
  51 void MarkedArgumentBuffer::slowAppend(JSValue v)
  52 {
  53     // As long as our size stays within our Vector's inline
  54     // capacity, all our values are allocated on the stack, and
  55     // therefore don't need explicit marking. Once our size exceeds
  56     // our Vector's inline capacity, though, our values move to the
  57     // heap, where they do need explicit marking.
  58     if (!m_markSet) {
  59         // FIXME: Even if v is not a JSCell*, if previous values in the buffer
  60         // are, then they won't be marked!
  61         if (Heap* heap = Heap::heap(v)) {
  62             ListSet& markSet = heap->markListSet();
  63             markSet.add(this);
  64             m_markSet = &markSet;
  65         }
  66     }
  67
  68     if (m_vector.size() < m_vector.capacity()) {
  69         m_vector.uncheckedAppend(v);
  70         return;
  71     }
  72
  73     // 4x growth would be excessive for a normal vector, but it's OK for Lists
  74     // because they're short-lived.
  75     m_vector.reserveCapacity(m_vector.capacity() * 4);
  76
  77     m_vector.uncheckedAppend(v);
  78     m_buffer = m_vector.data();
  79 }
  80
  81 } // namespace JSC