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39 #ifndef QV4ENGINEBASE_P_H
40 #define QV4ENGINEBASE_P_H
41 
42 //
43 //  W A R N I N G
44 //  -------------
45 //
46 // This file is not part of the Qt API.  It exists purely as an
47 // implementation detail.  This header file may change from version to
48 // version without notice, or even be removed.
49 //
50 // We mean it.
51 //
52 
53 #include <private/qv4global_p.h>
54 #include <private/qv4runtimeapi_p.h>
55 
56 QT_BEGIN_NAMESPACE
57 
58 namespace QV4 {
59 
60 struct CppStackFrame;
61 
62 // Base class for the execution engine
63 
64 #if defined(Q_CC_MSVC) || defined(Q_CC_GNU)
65 #pragma pack(push, 1)
66 #endif
67 struct Q_QML_EXPORT EngineBase {
68 
69     CppStackFrame *currentStackFrame = nullptr;
70 
71     Value *jsStackTop = nullptr;
72 
73     // The JIT expects hasException and isInterrupted to be in the same 32bit word in memory.
74     quint8 hasException = false;
75     // isInterrupted is expected to be set from a different thread
76 #if defined(Q_ATOMIC_INT8_IS_SUPPORTED)
77     QAtomicInteger<quint8> isInterrupted = false;
78     quint16 unused = 0;
79 #elif defined(Q_ATOMIC_INT16_IS_SUPPORTED)
80     quint8 unused = 0;
81     QAtomicInteger<quint16> isInterrupted = false;
82 #else
83 #   error V4 needs either 8bit or 16bit atomics.
84 #endif
85 
86     quint8 isExecutingInRegExpJIT = false;
87     quint8 padding[3];
88     MemoryManager *memoryManager = nullptr;
89 
90     qint32 callDepth = 0;
91     Value *jsStackLimit = nullptr;
92     Value *jsStackBase = nullptr;
93 
94     IdentifierTable *identifierTable = nullptr;
95     Object *globalObject = nullptr;
96 
97     // Exception handling
98     Value *exceptionValue = nullptr;
99 
100     enum InternalClassType {
101         Class_Empty,
102         Class_String,
103         Class_MemberData,
104         Class_SimpleArrayData,
105         Class_SparseArrayData,
106         Class_ExecutionContext,
107         Class_CallContext,
108         Class_QmlContext,
109         Class_Object,
110         Class_ArrayObject,
111         Class_FunctionObject,
112         Class_ArrowFunction,
113         Class_GeneratorFunction,
114         Class_GeneratorObject,
115         Class_StringObject,
116         Class_SymbolObject,
117         Class_ScriptFunction,
118         Class_ConstructorFunction,
119         Class_MemberFunction,
120         Class_MemberGeneratorFunction,
121         Class_ObjectProto,
122         Class_RegExp,
123         Class_RegExpObject,
124         Class_RegExpExecArray,
125         Class_ArgumentsObject,
126         Class_StrictArgumentsObject,
127         Class_ErrorObject,
128         Class_ErrorObjectWithMessage,
129         Class_ErrorProto,
130         Class_QmlContextWrapper,
131         Class_ProxyObject,
132         Class_ProxyFunctionObject,
133         Class_Symbol,
134         NClasses
135     };
136     Heap::InternalClass *classes[NClasses];
internalClassesEngineBase137     Heap::InternalClass *internalClasses(InternalClassType icType) { return classes[icType]; }
138 };
139 #if defined(Q_CC_MSVC) || defined(Q_CC_GNU)
140 #pragma pack(pop)
141 #endif
142 
143 Q_STATIC_ASSERT(std::is_standard_layout<EngineBase>::value);
144 Q_STATIC_ASSERT(offsetof(EngineBase, currentStackFrame) == 0);
145 Q_STATIC_ASSERT(offsetof(EngineBase, jsStackTop) == offsetof(EngineBase, currentStackFrame) + QT_POINTER_SIZE);
146 Q_STATIC_ASSERT(offsetof(EngineBase, hasException) == offsetof(EngineBase, jsStackTop) + QT_POINTER_SIZE);
147 Q_STATIC_ASSERT(offsetof(EngineBase, memoryManager) == offsetof(EngineBase, hasException) + 8);
148 Q_STATIC_ASSERT(offsetof(EngineBase, isInterrupted) + sizeof(EngineBase::isInterrupted) <= offsetof(EngineBase, hasException) + 4);
149 
150 }
151 
152 QT_END_NAMESPACE
153 
154 #endif
155