1/*
2 * Copyright (C) 2012-2018 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 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#if ENABLE(JIT)
29
30#include "JITStubRoutine.h"
31#include "JSObject.h"
32#include "WriteBarrier.h"
33#include <wtf/Vector.h>
34
35namespace JSC {
36
37class JITStubRoutineSet;
38
39// Use this stub routine if you know that your code might be on stack when
40// either GC or other kinds of stub deletion happen. Basicaly, if your stub
41// routine makes calls (either to JS code or to C++ code) then you should
42// assume that it's possible for that JS or C++ code to do something that
43// causes the system to try to delete your routine. Using this routine type
44// ensures that the actual deletion is delayed until the GC proves that the
45// routine is no longer running. You can also subclass this routine if you
46// want to mark additional objects during GC in those cases where the
47// routine is known to be executing, or if you want to force this routine to
48// keep other routines alive (for example due to the use of a slow-path
49// list which does not get reclaimed all at once).
50class GCAwareJITStubRoutine : public JITStubRoutine {
51public:
52 GCAwareJITStubRoutine(const MacroAssemblerCodeRef<JITStubRoutinePtrTag>&, VM&);
53 virtual ~GCAwareJITStubRoutine();
54
55 void markRequiredObjects(SlotVisitor& visitor)
56 {
57 markRequiredObjectsInternal(visitor);
58 }
59
60 void deleteFromGC();
61
62protected:
63 void observeZeroRefCount() override;
64
65 virtual void markRequiredObjectsInternal(SlotVisitor&);
66
67private:
68 friend class JITStubRoutineSet;
69
70 bool m_mayBeExecuting { false };
71 bool m_isJettisoned { false };
72};
73
74// Use this if you want to mark one additional object during GC if your stub
75// routine is known to be executing.
76class MarkingGCAwareJITStubRoutine : public GCAwareJITStubRoutine {
77public:
78 MarkingGCAwareJITStubRoutine(
79 const MacroAssemblerCodeRef<JITStubRoutinePtrTag>&, VM&, const JSCell* owner, const Vector<JSCell*>&);
80 virtual ~MarkingGCAwareJITStubRoutine();
81
82protected:
83 void markRequiredObjectsInternal(SlotVisitor&) override;
84
85private:
86 Vector<WriteBarrier<JSCell>> m_cells;
87};
88
89
90// The stub has exception handlers in it. So it clears itself from exception
91// handling table when it dies. It also frees space in CodeOrigin table
92// for new exception handlers to use the same DisposableCallSiteIndex.
93class GCAwareJITStubRoutineWithExceptionHandler : public MarkingGCAwareJITStubRoutine {
94public:
95 typedef GCAwareJITStubRoutine Base;
96
97 GCAwareJITStubRoutineWithExceptionHandler(const MacroAssemblerCodeRef<JITStubRoutinePtrTag>&, VM&, const JSCell* owner, const Vector<JSCell*>&, CodeBlock*, DisposableCallSiteIndex);
98
99 void aboutToDie() override;
100 void observeZeroRefCount() override;
101
102private:
103 CodeBlock* m_codeBlockWithExceptionHandler;
104 DisposableCallSiteIndex m_exceptionHandlerCallSiteIndex;
105};
106
107// Helper for easily creating a GC-aware JIT stub routine. For the varargs,
108// pass zero or more JSCell*'s. This will either create a JITStubRoutine, a
109// GCAwareJITStubRoutine, or an ObjectMarkingGCAwareJITStubRoutine as
110// appropriate. Generally you only need to pass pointers that will be used
111// after the first call to C++ or JS.
112//
113// Ref<JITStubRoutine> createJITStubRoutine(
114// const MacroAssemblerCodeRef<JITStubRoutinePtrTag>& code,
115// VM& vm,
116// const JSCell* owner,
117// bool makesCalls,
118// ...);
119//
120// Note that we don't actually use C-style varargs because that leads to
121// strange type-related problems. For example it would preclude us from using
122// our custom of passing '0' as NULL pointer. Besides, when I did try to write
123// this function using varargs, I ended up with more code than this simple
124// way.
125
126Ref<JITStubRoutine> createJITStubRoutine(
127 const MacroAssemblerCodeRef<JITStubRoutinePtrTag>&, VM&, const JSCell* owner, bool makesCalls,
128 const Vector<JSCell*>& = { },
129 CodeBlock* codeBlockForExceptionHandlers = nullptr, DisposableCallSiteIndex exceptionHandlingCallSiteIndex = DisposableCallSiteIndex());
130
131} // namespace JSC
132
133#endif // ENABLE(JIT)
134