2 * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 #ifndef RegisterFile_h
30 #define RegisterFile_h
32 #include "ExecutableAllocator.h"
34 #include <wtf/Noncopyable.h>
35 #include <wtf/PageReservation.h>
36 #include <wtf/VMTags.h>
40 class ConservativeRoots;
43 WTF_MAKE_NONCOPYABLE(RegisterFile);
45 enum CallFrameHeaderEntry {
46 CallFrameHeaderSize = 6,
52 ReturnPC = -2, // This is either an Instruction* or a pointer into JIT generated code stored as an Instruction*.
56 enum { ProgramCodeThisRegister = -CallFrameHeaderSize - 1 };
58 static const size_t defaultCapacity = 512 * 1024;
59 static const size_t commitSize = 16 * 1024;
60 // Allow 8k of excess registers before we start trying to reap the registerfile
61 static const ptrdiff_t maxExcessCapacity = 8 * 1024;
63 RegisterFile(size_t capacity = defaultCapacity);
66 void gatherConservativeRoots(ConservativeRoots&);
68 Register* begin() const { return static_cast<Register*>(m_reservation.base()); }
69 Register* end() const { return m_end; }
70 size_t size() const { return end() - begin(); }
72 bool grow(Register* newEnd);
73 void shrink(Register* newEnd);
75 static size_t committedByteCount();
76 static void initializeThreading();
78 Register* const * addressOfEnd() const
84 void releaseExcessCapacity();
85 void addToCommittedByteCount(long);
87 Register* m_commitEnd;
88 PageReservation m_reservation;
91 inline RegisterFile::RegisterFile(size_t capacity)
94 ASSERT(capacity && isPageAligned(capacity));
96 m_reservation = PageReservation::reserve(roundUpAllocationSize(capacity * sizeof(Register), commitSize), OSAllocator::JSVMStackPages);
97 m_end = static_cast<Register*>(m_reservation.base());
98 m_commitEnd = static_cast<Register*>(m_reservation.base());
101 inline void RegisterFile::shrink(Register* newEnd)
106 if (m_end == m_reservation.base() && (m_commitEnd - begin()) >= maxExcessCapacity)
107 releaseExcessCapacity();
110 inline bool RegisterFile::grow(Register* newEnd)
115 if (newEnd <= m_commitEnd) {
120 long delta = roundUpAllocationSize(reinterpret_cast<char*>(newEnd) - reinterpret_cast<char*>(m_commitEnd), commitSize);
121 if (reinterpret_cast<char*>(m_commitEnd) + delta > static_cast<char*>(m_reservation.base()) + m_reservation.size())
124 m_reservation.commit(m_commitEnd, delta);
125 addToCommittedByteCount(delta);
126 m_commitEnd = reinterpret_cast_ptr<Register*>(reinterpret_cast<char*>(m_commitEnd) + delta);
133 #endif // RegisterFile_h