1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25 #ifndef SHARE_OOPS_OOPSHIERARCHY_HPP
26 #define SHARE_OOPS_OOPSHIERARCHY_HPP
27
28 #include "metaprogramming/primitiveConversions.hpp"
29 #include "utilities/globalDefinitions.hpp"
30
31 #include <type_traits>
32
33 // OBJECT hierarchy
34 // This hierarchy is a representation hierarchy, i.e. if A is a superclass
35 // of B, A's representation is a prefix of B's representation.
36
37 // Global offset instead of address for an oop within a java object.
38 enum class narrowOop : uint32_t { null = 0 };
39
40 typedef void* OopOrNarrowOopStar;
41
42 #ifndef CHECK_UNHANDLED_OOPS
43
44 typedef class oopDesc* oop;
45 typedef class instanceOopDesc* instanceOop;
46 typedef class stackChunkOopDesc* stackChunkOop;
47 typedef class arrayOopDesc* arrayOop;
48 typedef class objArrayOopDesc* objArrayOop;
49 typedef class typeArrayOopDesc* typeArrayOop;
50 typedef class flatArrayOopDesc* flatArrayOop;
51
52 #else
53
54 // When CHECK_UNHANDLED_OOPS is defined, an "oop" is a class with a
55 // carefully chosen set of constructors and conversion operators to go
56 // to and from the underlying oopDesc pointer type.
57 //
58 // Because oop and its subclasses <type>Oop are class types, arbitrary
59 // conversions are not accepted by the compiler. Applying a cast to
60 // an oop will cause the best matched conversion operator to be
61 // invoked returning the underlying oopDesc* type if appropriate.
62 // No copy constructors, explicit user conversions or operators of
63 // numerical type should be defined within the oop class. Most C++
64 // compilers will issue a compile time error concerning the overloading
65 // ambiguity between operators of numerical and pointer types. If
66 // a conversion to or from an oop to a numerical type is needed,
67 // use the inline template methods, cast_*_oop, defined below.
68 //
69 // Converting null to oop to Handle implicit is no longer accepted by the
70 // compiler because there are too many steps in the conversion. Use Handle()
71 // instead, which generates less code anyway.
72
73 class Thread;
74 class oopDesc;
75
76 extern "C" bool CheckUnhandledOops;
77
78 // Extra verification when creating and using oops.
79 // Used to catch broken oops as soon as possible.
80 using CheckOopFunctionPointer = void(*)(oopDesc*);
81 extern CheckOopFunctionPointer check_oop_function;
82
83 class oop {
84 oopDesc* _o;
85
86 void register_oop();
87 void unregister_oop();
88
89 // Extra verification of the oop
90 void check_oop() const { if (check_oop_function != nullptr && _o != nullptr) check_oop_function(_o); }
91
92 void on_usage() const { check_oop(); }
93 void on_construction() { check_oop(); if (CheckUnhandledOops) register_oop(); }
94 void on_destruction() { if (CheckUnhandledOops) unregister_oop(); }
95
96 public:
97 oop() : _o(nullptr) { on_construction(); }
98 oop(const oop& o) : _o(o._o) { on_construction(); }
99 oop(oopDesc* o) : _o(o) { on_construction(); }
100 ~oop() {
101 on_destruction();
102 }
103
104 oopDesc* obj() const { on_usage(); return _o; }
105
106 oopDesc* operator->() const { return obj(); }
107 operator oopDesc* () const { return obj(); }
108
109 bool operator==(const oop& o) const { return obj() == o.obj(); }
110 bool operator!=(const oop& o) const { return obj() != o.obj(); }
111
112 bool operator==(std::nullptr_t) const { return obj() == nullptr; }
113 bool operator!=(std::nullptr_t) const { return obj() != nullptr; }
114
115 oop& operator=(const oop& o) { _o = o.obj(); return *this; }
116 };
117
118 template<>
119 struct PrimitiveConversions::Translate<oop> : public std::true_type {
120 typedef oop Value;
121 typedef oopDesc* Decayed;
122
123 static Decayed decay(Value x) { return x.obj(); }
124 static Value recover(Decayed x) { return oop(x); }
125 };
126
127 #define DEF_OOP(type) \
128 class type##OopDesc; \
129 class type##Oop : public oop { \
130 public: \
131 type##Oop() : oop() {} \
132 type##Oop(const type##Oop& o) : oop(o) {} \
133 type##Oop(const oop& o) : oop(o) {} \
134 type##Oop(type##OopDesc* o) : oop((oopDesc*)o) {} \
135 operator type##OopDesc* () const { return (type##OopDesc*)obj(); } \
136 type##OopDesc* operator->() const { \
137 return (type##OopDesc*)obj(); \
138 } \
139 type##Oop& operator=(const type##Oop& o) { \
140 oop::operator=(o); \
141 return *this; \
142 } \
143 }; \
144 \
145 template<> \
146 struct PrimitiveConversions::Translate<type##Oop> : public std::true_type { \
147 typedef type##Oop Value; \
148 typedef type##OopDesc* Decayed; \
149 \
150 static Decayed decay(Value x) { return (type##OopDesc*)x.obj(); } \
151 static Value recover(Decayed x) { return type##Oop(x); } \
152 };
153
154 DEF_OOP(instance);
155 DEF_OOP(stackChunk);
156 DEF_OOP(array);
157 DEF_OOP(objArray);
158 DEF_OOP(typeArray);
159 DEF_OOP(flatArray);
160
161 #endif // CHECK_UNHANDLED_OOPS
162
163 // Cast functions to convert to and from oops.
164 template <typename T> inline oop cast_to_oop(T value) {
165 return (oopDesc*)value;
166 }
167 template <typename T> inline T cast_from_oop(oop o) {
168 return (T)(CHECK_UNHANDLED_OOPS_ONLY((oopDesc*))o);
169 }
170
171 inline intptr_t p2i(narrowOop o) {
172 return static_cast<intptr_t>(o);
173 }
174
175 // The metadata hierarchy is separate from the oop hierarchy
176
177 // class MetaspaceObj
178 class ConstMethod;
179 class ConstantPoolCache;
180 class MethodData;
181 // class Metadata
182 class Method;
183 class ConstantPool;
184
185 // The klass hierarchy is separate from the oop hierarchy.
186
187 class Klass;
188 class InstanceKlass;
189 class InlineKlass;
190 class InstanceMirrorKlass;
191 class InstanceClassLoaderKlass;
192 class InstanceRefKlass;
193 class InstanceStackChunkKlass;
194 class ArrayKlass;
195 class ObjArrayKlass;
196 class TypeArrayKlass;
197 class FlatArrayKlass;
198
199 #endif // SHARE_OOPS_OOPSHIERARCHY_HPP