1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
/*
* Copyright (C) 2012, 2014 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef JITStubRoutine_h
#define JITStubRoutine_h
#if ENABLE(JIT)
#include "ExecutableAllocator.h"
#include "MacroAssemblerCodeRef.h"
#include <wtf/RefCounted.h>
#include <wtf/Vector.h>
namespace JSC {
class JITStubRoutineSet;
// This is a base-class for JIT stub routines, and also the class you want
// to instantiate directly if you have a routine that does not need any
// help from the GC. If in doubt, use one of the other stub routines. But
// if you know for sure that the stub routine cannot be on the stack while
// someone triggers a stub routine reset, then using this will speed up
// memory reclamation. One case where a stub routine satisfies this
// condition is if it doesn't make any calls, to either C++ or JS code. In
// such a routine you know that it cannot be on the stack when anything
// interesting happens.
// See GCAwareJITStubRoutine.h for the other stub routines.
class JITStubRoutine {
WTF_MAKE_NONCOPYABLE(JITStubRoutine);
WTF_MAKE_FAST_ALLOCATED;
public:
JITStubRoutine(const MacroAssemblerCodeRef& code)
: m_code(code)
, m_refCount(1)
{
}
// Use this if you want to pass a CodePtr to someone who insists on taking
// a RefPtr<JITStubRoutine>.
static Ref<JITStubRoutine> createSelfManagedRoutine(
MacroAssemblerCodePtr rawCodePointer)
{
return adoptRef(*new JITStubRoutine(MacroAssemblerCodeRef::createSelfManagedCodeRef(rawCodePointer)));
}
virtual ~JITStubRoutine();
virtual void aboutToDie() { }
// MacroAssemblerCodeRef is copyable, but at the cost of reference
// counting churn. Returning a reference is a good way of reducing
// the churn.
const MacroAssemblerCodeRef& code() const { return m_code; }
static MacroAssemblerCodePtr asCodePtr(PassRefPtr<JITStubRoutine> stubRoutine)
{
if (!stubRoutine)
return MacroAssemblerCodePtr();
MacroAssemblerCodePtr result = stubRoutine->code().code();
ASSERT(!!result);
return result;
}
void ref()
{
m_refCount++;
}
void deref()
{
if (--m_refCount)
return;
observeZeroRefCount();
}
// Helpers for the GC to determine how to deal with marking JIT stub
// routines.
uintptr_t startAddress() const { return m_code.executableMemory()->startAsInteger(); }
uintptr_t endAddress() const { return m_code.executableMemory()->endAsInteger(); }
static uintptr_t addressStep() { return jitAllocationGranule; }
static bool canPerformRangeFilter()
{
#if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
return true;
#else
return false;
#endif
}
static uintptr_t filteringStartAddress()
{
#if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
return startOfFixedExecutableMemoryPool;
#else
UNREACHABLE_FOR_PLATFORM();
return 0;
#endif
}
static size_t filteringExtentSize()
{
#if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
return fixedExecutableMemoryPoolSize;
#else
UNREACHABLE_FOR_PLATFORM();
return 0;
#endif
}
static bool passesFilter(uintptr_t address)
{
if (!canPerformRangeFilter()) {
// Just check that the address doesn't use any special values that would make
// our hashtables upset.
return address >= jitAllocationGranule && address != std::numeric_limits<uintptr_t>::max();
}
if (address - filteringStartAddress() >= filteringExtentSize())
return false;
return true;
}
// Return true if you are still valid after. Return false if you are now invalid. If you return
// false, you will usually not do any clearing because the idea is that you will simply be
// destroyed.
virtual bool visitWeak(VM&);
protected:
virtual void observeZeroRefCount();
MacroAssemblerCodeRef m_code;
unsigned m_refCount;
};
// Helper for the creation of simple stub routines that need no help from the GC.
#define FINALIZE_CODE_FOR_STUB(codeBlock, patchBuffer, dataLogFArguments) \
(adoptRef(new JITStubRoutine(FINALIZE_CODE_FOR((codeBlock), (patchBuffer), dataLogFArguments))))
} // namespace JSC
#endif // ENABLE(JIT)
#endif // JITStubRoutine_h
|
