1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
8 *
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
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23 */
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 // Global offset instead of address for an oop within a java object.
37 enum class narrowOop : uint32_t { null = 0 };
38
39 // If compressed klass pointers then use narrowKlass.
40 typedef juint narrowKlass;
41
42 typedef void* OopOrNarrowOopStar;
43
44 #ifndef CHECK_UNHANDLED_OOPS
45
46 typedef class oopDesc* oop;
47 typedef class instanceOopDesc* instanceOop;
48 typedef class arrayOopDesc* arrayOop;
49 typedef class objArrayOopDesc* objArrayOop;
50 typedef class typeArrayOopDesc* typeArrayOop;
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 class oop {
79 oopDesc* _o;
80
81 void register_oop();
82 void unregister_oop();
83
register_if_checking()84 void register_if_checking() {
85 if (CheckUnhandledOops) register_oop();
86 }
87
88 public:
oop()89 oop() : _o(nullptr) { register_if_checking(); }
oop(const oop & o)90 oop(const oop& o) : _o(o._o) { register_if_checking(); }
oop(oopDesc * o)91 oop(oopDesc* o) : _o(o) { register_if_checking(); }
~oop()92 ~oop() {
93 if (CheckUnhandledOops) unregister_oop();
94 }
95
obj() const96 oopDesc* obj() const { return _o; }
operator ->() const97 oopDesc* operator->() const { return _o; }
operator oopDesc*() const98 operator oopDesc* () const { return _o; }
99
operator ==(const oop & o) const100 bool operator==(const oop& o) const { return _o == o._o; }
operator !=(const oop & o) const101 bool operator!=(const oop& o) const { return _o != o._o; }
102
operator ==(std::nullptr_t) const103 bool operator==(std::nullptr_t) const { return _o == nullptr; }
operator !=(std::nullptr_t) const104 bool operator!=(std::nullptr_t) const { return _o != nullptr; }
105
operator =(const oop & o)106 oop& operator=(const oop& o) { _o = o._o; return *this; }
107 };
108
109 template<>
110 struct PrimitiveConversions::Translate<oop> : public TrueType {
111 typedef oop Value;
112 typedef oopDesc* Decayed;
113
decayPrimitiveConversions::Translate114 static Decayed decay(Value x) { return x.obj(); }
recoverPrimitiveConversions::Translate115 static Value recover(Decayed x) { return oop(x); }
116 };
117
118 #define DEF_OOP(type) \
119 class type##OopDesc; \
120 class type##Oop : public oop { \
121 public: \
122 type##Oop() : oop() {} \
123 type##Oop(const type##Oop& o) : oop(o) {} \
124 type##Oop(const oop& o) : oop(o) {} \
125 type##Oop(type##OopDesc* o) : oop((oopDesc*)o) {} \
126 operator type##OopDesc* () const { return (type##OopDesc*)obj(); } \
127 type##OopDesc* operator->() const { \
128 return (type##OopDesc*)obj(); \
129 } \
130 type##Oop& operator=(const type##Oop& o) { \
131 oop::operator=(o); \
132 return *this; \
133 } \
134 }; \
135 \
136 template<> \
137 struct PrimitiveConversions::Translate<type##Oop> : public TrueType { \
138 typedef type##Oop Value; \
139 typedef type##OopDesc* Decayed; \
140 \
141 static Decayed decay(Value x) { return (type##OopDesc*)x.obj(); } \
142 static Value recover(Decayed x) { return type##Oop(x); } \
143 };
144
145 DEF_OOP(instance);
146 DEF_OOP(array);
147 DEF_OOP(objArray);
148 DEF_OOP(typeArray);
149
150 #endif // CHECK_UNHANDLED_OOPS
151
152 // Cast functions to convert to and from oops.
cast_to_oop(T value)153 template <typename T> inline oop cast_to_oop(T value) {
154 return (oopDesc*)value;
155 }
cast_from_oop(oop o)156 template <typename T> inline T cast_from_oop(oop o) {
157 return (T)(CHECK_UNHANDLED_OOPS_ONLY((oopDesc*))o);
158 }
159
160 // The metadata hierarchy is separate from the oop hierarchy
161
162 // class MetaspaceObj
163 class ConstMethod;
164 class ConstantPoolCache;
165 class MethodData;
166 // class Metadata
167 class Method;
168 class ConstantPool;
169 // class CHeapObj
170 class CompiledICHolder;
171
172
173 // The klass hierarchy is separate from the oop hierarchy.
174
175 class Klass;
176 class InstanceKlass;
177 class InstanceMirrorKlass;
178 class InstanceClassLoaderKlass;
179 class InstanceRefKlass;
180 class ArrayKlass;
181 class ObjArrayKlass;
182 class TypeArrayKlass;
183
184 #endif // SHARE_OOPS_OOPSHIERARCHY_HPP
185