1/*
2 * Copyright (C) 2008-2017 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#pragma once
30
31#if ENABLE(C_LOOP)
32
33#include "Register.h"
34#include <wtf/Noncopyable.h>
35#include <wtf/PageReservation.h>
36
37namespace JSC {
38
39 class CodeBlockSet;
40 class ConservativeRoots;
41 class JITStubRoutineSet;
42 class VM;
43 class LLIntOffsetsExtractor;
44
45 class CLoopStack {
46 WTF_MAKE_NONCOPYABLE(CLoopStack);
47 public:
48 // Allow 8k of excess registers before we start trying to reap the stack
49 static const ptrdiff_t maxExcessCapacity = 8 * 1024;
50
51 CLoopStack(VM&);
52 ~CLoopStack();
53
54 bool ensureCapacityFor(Register* newTopOfStack);
55
56 bool containsAddress(Register* address) { return (lowAddress() <= address && address < highAddress()); }
57 static size_t committedByteCount();
58
59 void gatherConservativeRoots(ConservativeRoots&, JITStubRoutineSet&, CodeBlockSet&);
60 void sanitizeStack();
61
62 inline void* currentStackPointer();
63 void setCurrentStackPointer(void* sp) { m_currentStackPointer = sp; }
64
65 size_t size() const { return highAddress() - lowAddress(); }
66
67 void setSoftReservedZoneSize(size_t);
68 bool isSafeToRecurse() const;
69
70 private:
71 Register* lowAddress() const
72 {
73 return m_end;
74 }
75
76 Register* highAddress() const
77 {
78 return reinterpret_cast_ptr<Register*>(static_cast<char*>(m_reservation.base()) + m_reservation.size());
79 }
80
81 Register* reservationTop() const
82 {
83 char* reservationTop = static_cast<char*>(m_reservation.base());
84 return reinterpret_cast_ptr<Register*>(reservationTop);
85 }
86
87 bool grow(Register* newTopOfStack);
88 void releaseExcessCapacity();
89 void addToCommittedByteCount(long);
90
91 void setCLoopStackLimit(Register* newTopOfStack);
92
93 VM& m_vm;
94 CallFrame*& m_topCallFrame;
95
96 // The following is always true:
97 // reservationTop() <= m_commitTop <= m_end <= m_currentStackPointer <= highAddress()
98 Register* m_end; // lowest address of JS allocatable stack memory.
99 Register* m_commitTop; // lowest address of committed memory.
100 PageReservation m_reservation;
101 void* m_lastStackPointer;
102 void* m_currentStackPointer;
103 ptrdiff_t m_softReservedZoneSizeInRegisters;
104
105 friend class LLIntOffsetsExtractor;
106 };
107
108} // namespace JSC
109
110#endif // ENABLE(C_LOOP)
111