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39
40#ifndef QV4EXECUTABLEALLOCATOR_H
41#define QV4EXECUTABLEALLOCATOR_H
42
43//
44// W A R N I N G
45// -------------
46//
47// This file is not part of the Qt API. It exists purely as an
48// implementation detail. This header file may change from version to
49// version without notice, or even be removed.
50//
51// We mean it.
52//
53
54#include "qv4global_p.h"
55
56#include <QMultiMap>
57#include <QHash>
58#include <QVector>
59#include <QByteArray>
60#include <QMutex>
61
62namespace WTF {
63class PageAllocation;
64}
65
66QT_BEGIN_NAMESPACE
67
68namespace QV4 {
69
70class Q_QML_AUTOTEST_EXPORT ExecutableAllocator
71{
72public:
73 struct ChunkOfPages;
74 struct Allocation;
75
76 ExecutableAllocator();
77 ~ExecutableAllocator();
78
79 Allocation *allocate(size_t size);
80 void free(Allocation *allocation);
81
82 struct Allocation
83 {
84 Allocation()
85 : size(0)
86 , free(true)
87 {}
88
89 void *memoryStart() const;
90 size_t memorySize() const { return size; }
91
92 void *exceptionHandlerStart() const;
93 size_t exceptionHandlerSize() const;
94
95 void *codeStart() const;
96
97 void invalidate() { addr = 0; }
98 bool isValid() const { return addr != 0; }
99 void deallocate(ExecutableAllocator *allocator);
100
101 private:
102 ~Allocation() {}
103
104 friend class ExecutableAllocator;
105
106 Allocation *split(size_t dividingSize);
107 bool mergeNext(ExecutableAllocator *allocator);
108 bool mergePrevious(ExecutableAllocator *allocator);
109
110 quintptr addr = 0;
111 uint size : 31; // More than 2GB of function code? nah :)
112 uint free : 1;
113 Allocation *next = nullptr;
114 Allocation *prev = nullptr;
115 };
116
117 // for debugging / unit-testing
118 int freeAllocationCount() const { return freeAllocations.count(); }
119 int chunkCount() const { return chunks.count(); }
120
121 struct ChunkOfPages
122 {
123 ChunkOfPages()
124
125 {}
126 ~ChunkOfPages();
127
128 WTF::PageAllocation *pages = nullptr;
129 Allocation *firstAllocation = nullptr;
130
131 bool contains(Allocation *alloc) const;
132 };
133
134 ChunkOfPages *chunkForAllocation(Allocation *allocation) const;
135
136private:
137 QMultiMap<size_t, Allocation*> freeAllocations;
138 QMap<quintptr, ChunkOfPages*> chunks;
139 mutable QRecursiveMutex mutex;
140};
141
142}
143
144QT_END_NAMESPACE
145
146#endif // QV4EXECUTABLEALLOCATOR_H
147

source code of qtdeclarative/src/qml/jsruntime/qv4executableallocator_p.h