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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 
62 namespace WTF {
63 class PageAllocation;
64 }
65 
66 QT_BEGIN_NAMESPACE
67 
68 namespace QV4 {
69 
70 class Q_QML_AUTOTEST_EXPORT ExecutableAllocator
71 {
72 public:
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     {
AllocationAllocation84         Allocation()
85             : size(0)
86             , free(true)
87         {}
88 
89         void *memoryStart() const;
memorySizeAllocation90         size_t memorySize() const { return size; }
91 
92         void *exceptionHandlerStart() const;
93         size_t exceptionHandlerSize() const;
94 
95         void *codeStart() const;
96 
invalidateAllocation97         void invalidate() { addr = 0; }
isValidAllocation98         bool isValid() const { return addr != 0; }
99         void deallocate(ExecutableAllocator *allocator);
100 
101     private:
~AllocationAllocation102         ~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
freeAllocationCount()118     int freeAllocationCount() const { return freeAllocations.count(); }
chunkCount()119     int chunkCount() const { return chunks.count(); }
120 
121     struct ChunkOfPages
122     {
ChunkOfPagesChunkOfPages123         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 
136 private:
137     QMultiMap<size_t, Allocation*> freeAllocations;
138     QMap<quintptr, ChunkOfPages*> chunks;
139     mutable QRecursiveMutex mutex;
140 };
141 
142 }
143 
144 QT_END_NAMESPACE
145 
146 #endif // QV4EXECUTABLEALLOCATOR_H
147