1/*
2 * Copyright (C) 2008, 2013, 2014 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 *
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 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.
16 *
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.
27 */
28
29#include "config.h"
30#include "JSStackInlines.h"
31
32#include "ConservativeRoots.h"
33#include "Interpreter.h"
34#include "JSCInlines.h"
35#include "Options.h"
36
37namespace JSC {
38
39#if !ENABLE(JIT)
40static size_t committedBytesCount = 0;
41
42static Mutex& stackStatisticsMutex()
43{
44    DEPRECATED_DEFINE_STATIC_LOCAL(Mutex, staticMutex, ());
45    return staticMutex;
46}
47#endif // !ENABLE(JIT)
48
49JSStack::JSStack(VM& vm)
50    : m_vm(vm)
51    , m_topCallFrame(vm.topCallFrame)
52#if !ENABLE(JIT)
53    , m_end(0)
54    , m_reservedZoneSizeInRegisters(0)
55#endif
56{
57#if !ENABLE(JIT)
58    size_t capacity = Options::maxPerThreadStackUsage();
59    ASSERT(capacity && isPageAligned(capacity));
60
61    m_reservation = PageReservation::reserve(WTF::roundUpToMultipleOf(commitSize, capacity), OSAllocator::JSVMStackPages);
62    setStackLimit(highAddress());
63    m_commitTop = highAddress();
64
65    m_lastStackTop = baseOfStack();
66#endif // !ENABLE(JIT)
67
68    m_topCallFrame = 0;
69}
70
71#if !ENABLE(JIT)
72JSStack::~JSStack()
73{
74    ptrdiff_t sizeToDecommit = reinterpret_cast<char*>(highAddress()) - reinterpret_cast<char*>(m_commitTop);
75    m_reservation.decommit(reinterpret_cast<void*>(m_commitTop), sizeToDecommit);
76    addToCommittedByteCount(-sizeToDecommit);
77    m_reservation.deallocate();
78}
79
80bool JSStack::growSlowCase(Register* newTopOfStack)
81{
82    Register* newTopOfStackWithReservedZone = newTopOfStack - m_reservedZoneSizeInRegisters;
83
84    // If we have already committed enough memory to satisfy this request,
85    // just update the end pointer and return.
86    if (newTopOfStackWithReservedZone >= m_commitTop) {
87        setStackLimit(newTopOfStack);
88        return true;
89    }
90
91    // Compute the chunk size of additional memory to commit, and see if we
92    // have it is still within our budget. If not, we'll fail to grow and
93    // return false.
94    ptrdiff_t delta = reinterpret_cast<char*>(m_commitTop) - reinterpret_cast<char*>(newTopOfStackWithReservedZone);
95    delta = WTF::roundUpToMultipleOf(commitSize, delta);
96    Register* newCommitTop = m_commitTop - (delta / sizeof(Register));
97    if (newCommitTop < reservationTop())
98        return false;
99
100    // Otherwise, the growth is still within our budget. Go ahead and commit
101    // it and return true.
102    m_reservation.commit(newCommitTop, delta);
103    addToCommittedByteCount(delta);
104    m_commitTop = newCommitTop;
105    setStackLimit(newTopOfStack);
106    return true;
107}
108
109void JSStack::gatherConservativeRoots(ConservativeRoots& conservativeRoots)
110{
111    conservativeRoots.add(topOfStack() + 1, highAddress());
112}
113
114void JSStack::gatherConservativeRoots(ConservativeRoots& conservativeRoots, JITStubRoutineSet& jitStubRoutines, CodeBlockSet& codeBlocks)
115{
116    conservativeRoots.add(topOfStack() + 1, highAddress(), jitStubRoutines, codeBlocks);
117}
118
119void JSStack::sanitizeStack()
120{
121#if !defined(ADDRESS_SANITIZER)
122    ASSERT(topOfStack() <= baseOfStack());
123
124    if (m_lastStackTop < topOfStack()) {
125        char* begin = reinterpret_cast<char*>(m_lastStackTop + 1);
126        char* end = reinterpret_cast<char*>(topOfStack() + 1);
127        memset(begin, 0, end - begin);
128    }
129
130    m_lastStackTop = topOfStack();
131#endif
132}
133
134void JSStack::releaseExcessCapacity()
135{
136    Register* highAddressWithReservedZone = highAddress() - m_reservedZoneSizeInRegisters;
137    ptrdiff_t delta = reinterpret_cast<char*>(highAddressWithReservedZone) - reinterpret_cast<char*>(m_commitTop);
138    m_reservation.decommit(m_commitTop, delta);
139    addToCommittedByteCount(-delta);
140    m_commitTop = highAddressWithReservedZone;
141}
142
143void JSStack::initializeThreading()
144{
145    stackStatisticsMutex();
146}
147
148void JSStack::addToCommittedByteCount(long byteCount)
149{
150    MutexLocker locker(stackStatisticsMutex());
151    ASSERT(static_cast<long>(committedBytesCount) + byteCount > -1);
152    committedBytesCount += byteCount;
153}
154
155void JSStack::setReservedZoneSize(size_t reservedZoneSize)
156{
157    m_reservedZoneSizeInRegisters = reservedZoneSize / sizeof(Register);
158    if (m_commitTop >= (m_end + 1) - m_reservedZoneSizeInRegisters)
159        growSlowCase(m_end + 1);
160}
161#endif // !ENABLE(JIT)
162
163#if ENABLE(JIT)
164Register* JSStack::lowAddress() const
165{
166    ASSERT(wtfThreadData().stack().isGrowingDownward());
167    return reinterpret_cast<Register*>(m_vm.stackLimit());
168}
169
170Register* JSStack::highAddress() const
171{
172    ASSERT(wtfThreadData().stack().isGrowingDownward());
173    return reinterpret_cast<Register*>(wtfThreadData().stack().origin());
174}
175#endif // ENABLE(JIT)
176
177size_t JSStack::committedByteCount()
178{
179#if !ENABLE(JIT)
180    MutexLocker locker(stackStatisticsMutex());
181    return committedBytesCount;
182#else
183    // When using the C stack, we don't know how many stack pages are actually
184    // committed. So, we use the current stack usage as an estimate.
185    ASSERT(wtfThreadData().stack().isGrowingDownward());
186    int8_t* current = reinterpret_cast<int8_t*>(&current);
187    int8_t* high = reinterpret_cast<int8_t*>(wtfThreadData().stack().origin());
188    return high - current;
189#endif
190}
191
192} // namespace JSC
193