1/*
2 * Copyright (C) 2008, 2009, 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#ifndef JSStack_h
30#define JSStack_h
31
32#include "ExecutableAllocator.h"
33#include "Register.h"
34#include <wtf/Noncopyable.h>
35#include <wtf/PageReservation.h>
36#include <wtf/VMTags.h>
37
38namespace JSC {
39
40    class CodeBlockSet;
41    class ConservativeRoots;
42    class ExecState;
43    class JITStubRoutineSet;
44    class VM;
45    class LLIntOffsetsExtractor;
46
47    struct Instruction;
48    typedef ExecState CallFrame;
49
50    struct CallerFrameAndPC {
51        CallFrame* callerFrame;
52        Instruction* pc;
53    };
54
55    class JSStack {
56        WTF_MAKE_NONCOPYABLE(JSStack);
57    public:
58        enum CallFrameHeaderEntry {
59            CallerFrameAndPCSize = sizeof(CallerFrameAndPC) / sizeof(Register),
60            CodeBlock = CallerFrameAndPCSize,
61            ScopeChain,
62            Callee,
63            ArgumentCount,
64            CallFrameHeaderSize,
65
66            // The following entries are not part of the CallFrameHeader but are provided here as a convenience:
67            ThisArgument = CallFrameHeaderSize,
68            FirstArgument,
69        };
70
71        static const size_t commitSize = 16 * 1024;
72        // Allow 8k of excess registers before we start trying to reap the stack
73        static const ptrdiff_t maxExcessCapacity = 8 * 1024;
74
75        JSStack(VM&);
76
77        bool ensureCapacityFor(Register* newTopOfStack);
78
79        bool containsAddress(Register* address) { return (lowAddress() <= address && address < highAddress()); }
80        static size_t committedByteCount();
81
82#if ENABLE(JIT)
83        void gatherConservativeRoots(ConservativeRoots&) { }
84        void gatherConservativeRoots(ConservativeRoots&, JITStubRoutineSet&, CodeBlockSet&) { }
85        void sanitizeStack() { }
86        static void initializeThreading() { }
87#else
88        ~JSStack();
89
90        void gatherConservativeRoots(ConservativeRoots&);
91        void gatherConservativeRoots(ConservativeRoots&, JITStubRoutineSet&, CodeBlockSet&);
92        void sanitizeStack();
93
94        Register* baseOfStack() const
95        {
96            return highAddress() - 1;
97        }
98
99        size_t size() const { return highAddress() - lowAddress(); }
100
101        static void initializeThreading();
102
103        void setReservedZoneSize(size_t);
104
105        inline Register* topOfStack();
106#endif // ENABLE(JIT)
107
108    private:
109
110#if !ENABLE(JIT)
111        Register* lowAddress() const
112        {
113            return m_end + 1;
114        }
115
116        Register* highAddress() const
117        {
118            return reinterpret_cast_ptr<Register*>(static_cast<char*>(m_reservation.base()) + m_reservation.size());
119        }
120#else
121        Register* lowAddress() const;
122        Register* highAddress() const;
123#endif // !ENABLE(JIT)
124
125#if !ENABLE(JIT)
126        inline Register* topOfFrameFor(CallFrame*);
127
128        Register* reservationTop() const
129        {
130            char* reservationTop = static_cast<char*>(m_reservation.base());
131            return reinterpret_cast_ptr<Register*>(reservationTop);
132        }
133
134        bool grow(Register* newTopOfStack);
135        bool growSlowCase(Register* newTopOfStack);
136        void shrink(Register* newTopOfStack);
137        void releaseExcessCapacity();
138        void addToCommittedByteCount(long);
139
140        void setStackLimit(Register* newTopOfStack);
141#endif // !ENABLE(JIT)
142
143        VM& m_vm;
144        CallFrame*& m_topCallFrame;
145#if !ENABLE(JIT)
146        Register* m_end;
147        Register* m_commitTop;
148        PageReservation m_reservation;
149        Register* m_lastStackTop;
150        ptrdiff_t m_reservedZoneSizeInRegisters;
151#endif // !ENABLE(JIT)
152
153        friend class LLIntOffsetsExtractor;
154    };
155
156} // namespace JSC
157
158#endif // JSStack_h
159