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/integralConstant.hpp"
29 #include "metaprogramming/primitiveConversions.hpp"
30 #include "utilities/globalDefinitions.hpp"
31
32 // OBJECT hierarchy
33 // This hierarchy is a representation hierarchy, i.e. if A is a superclass
34 // of B, A's representation is a prefix of B's representation.
35
36 typedef juint narrowOop; // Offset instead of address for an oop within a java object
37
38 // If compressed klass pointers then use narrowKlass.
39 typedef juint narrowKlass;
40
41 typedef void* OopOrNarrowOopStar;
42
43 #ifndef CHECK_UNHANDLED_OOPS
44
45 typedef class oopDesc* oop;
46 typedef class instanceOopDesc* instanceOop;
47 typedef class arrayOopDesc* arrayOop;
48 typedef class objArrayOopDesc* objArrayOop;
49 typedef class typeArrayOopDesc* typeArrayOop;
50
51 #else
52
53 // When CHECK_UNHANDLED_OOPS is defined, an "oop" is a class with a
54 // carefully chosen set of constructors and conversion operators to go
55 // to and from the underlying oopDesc pointer type.
56 //
57 // Because oop and its subclasses <type>Oop are class types, arbitrary
58 // conversions are not accepted by the compiler. Applying a cast to
59 // an oop will cause the best matched conversion operator to be
60 // invoked returning the underlying oopDesc* type if appropriate.
61 // No copy constructors, explicit user conversions or operators of
62 // numerical type should be defined within the oop class. Most C++
63 // compilers will issue a compile time error concerning the overloading
64 // ambiguity between operators of numerical and pointer types. If
65 // a conversion to or from an oop to a numerical type is needed,
66 // use the inline template methods, cast_*_oop, defined below.
67 //
68 // Converting NULL to oop to Handle implicit is no longer accepted by the
69 // compiler because there are too many steps in the conversion. Use Handle()
70 // instead, which generates less code anyway.
71
72 class Thread;
73 class PromotedObject;
74 class oopDesc;
75
76 extern "C" bool CheckUnhandledOops;
77
78 class oop {
79 oopDesc* _o;
80
81 void register_oop();
82 void unregister_oop();
83
84 public:
85 void set_obj(const void* p) {
86 raw_set_obj(p);
87 if (CheckUnhandledOops) register_oop();
88 }
89 void raw_set_obj(const void* p) { _o = (oopDesc*)p; }
90
91 oop() { set_obj(NULL); }
92 oop(const oop& o) { set_obj(o.obj()); }
93 oop(const volatile oop& o) { set_obj(o.obj()); }
94 oop(const void* p) { set_obj(p); }
95 ~oop() {
96 if (CheckUnhandledOops) unregister_oop();
97 }
98
99 oopDesc* obj() const volatile { return _o; }
100
101 // General access
102 oopDesc* operator->() const { return obj(); }
103 bool operator==(const oop o) const { return obj() == o.obj(); }
104 bool operator==(void *p) const { return obj() == p; }
105 bool operator!=(const volatile oop o) const { return obj() != o.obj(); }
106 bool operator!=(void *p) const { return obj() != p; }
107
108 // Assignment
109 oop& operator=(const oop& o) { _o = o.obj(); return *this; }
110 volatile oop& operator=(const oop& o) volatile { _o = o.obj(); return *this; }
111 volatile oop& operator=(const volatile oop& o) volatile { _o = o.obj(); return *this; }
112
113 // Explict user conversions
114 operator void* () const { return (void *)obj(); }
115 #ifndef SOLARIS
116 operator void* () const volatile { return (void *)obj(); }
117 #endif
118 operator HeapWord* () const { return (HeapWord*)obj(); }
119 operator oopDesc* () const volatile { return obj(); }
120 operator intptr_t* () const { return (intptr_t*)obj(); }
121 operator PromotedObject* () const { return (PromotedObject*)obj(); }
122 operator address () const { return (address)obj(); }
123
124 // from javaCalls.cpp
125 operator jobject () const { return (jobject)obj(); }
126
127 // from parNewGeneration and other things that want to get to the end of
128 // an oop for stuff (like ObjArrayKlass.cpp)
129 operator oop* () const { return (oop *)obj(); }
130 };
131
132 template<>
133 struct PrimitiveConversions::Translate<oop> : public TrueType {
134 typedef oop Value;
135 typedef oopDesc* Decayed;
136
137 static Decayed decay(Value x) { return x.obj(); }
138 static Value recover(Decayed x) { return oop(x); }
139 };
140
141 #define DEF_OOP(type) \
142 class type##OopDesc; \
143 class type##Oop : public oop { \
144 public: \
145 type##Oop() : oop() {} \
146 type##Oop(const oop& o) : oop(o) {} \
147 type##Oop(const volatile oop& o) : oop(o) {} \
148 type##Oop(const void* p) : oop(p) {} \
149 operator type##OopDesc* () const { return (type##OopDesc*)obj(); } \
150 type##OopDesc* operator->() const { \
151 return (type##OopDesc*)obj(); \
152 } \
153 type##Oop& operator=(const type##Oop& o) { \
154 oop::operator=(o); \
155 return *this; \
156 } \
157 volatile type##Oop& operator=(const type##Oop& o) volatile { \
158 (void)const_cast<oop&>(oop::operator=(o)); \
159 return *this; \
160 } \
161 volatile type##Oop& operator=(const volatile type##Oop& o) volatile {\
162 (void)const_cast<oop&>(oop::operator=(o)); \
163 return *this; \
164 } \
165 }; \
166 \
167 template<> \
168 struct PrimitiveConversions::Translate<type##Oop> : public TrueType { \
169 typedef type##Oop Value; \
170 typedef type##OopDesc* Decayed; \
171 \
172 static Decayed decay(Value x) { return (type##OopDesc*)x.obj(); } \
173 static Value recover(Decayed x) { return type##Oop(x); } \
174 };
175
176 DEF_OOP(instance);
177 DEF_OOP(array);
178 DEF_OOP(objArray);
179 DEF_OOP(typeArray);
180
181 #endif // CHECK_UNHANDLED_OOPS
182
183 // For CHECK_UNHANDLED_OOPS, it is ambiguous C++ behavior to have the oop
184 // structure contain explicit user defined conversions of both numerical
185 // and pointer type. Define inline methods to provide the numerical conversions.
186 template <class T> inline oop cast_to_oop(T value) {
187 return (oop)(CHECK_UNHANDLED_OOPS_ONLY((void *))(value));
188 }
189 template <class T> inline T cast_from_oop(oop o) {
190 return (T)(CHECK_UNHANDLED_OOPS_ONLY((void*))o);
191 }
192
193 inline bool check_obj_alignment(void* ptr) {
194 return (uintptr_t(ptr) & MinObjAlignmentInBytesMask) == 0;
195 }
196
197 // The metadata hierarchy is separate from the oop hierarchy
198
199 // class MetaspaceObj
200 class ConstMethod;
201 class ConstantPoolCache;
202 class MethodData;
203 // class Metadata
204 class Method;
205 class ConstantPool;
206 // class CHeapObj
207 class CompiledICHolder;
208
209
210 // The klass hierarchy is separate from the oop hierarchy.
211
212 class Klass;
213 class InstanceKlass;
214 class InstanceMirrorKlass;
215 class InstanceClassLoaderKlass;
216 class InstanceRefKlass;
217 class ArrayKlass;
218 class ObjArrayKlass;
219 class TypeArrayKlass;
220
221 #endif // SHARE_OOPS_OOPSHIERARCHY_HPP