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.
4 *
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 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
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 typedef class flatArrayOopDesc* flatArrayOop;
52
53 #else
54
55 // When CHECK_UNHANDLED_OOPS is defined, an "oop" is a class with a
56 // carefully chosen set of constructors and conversion operators to go
57 // to and from the underlying oopDesc pointer type.
58 //
59 // Because oop and its subclasses <type>Oop are class types, arbitrary
60 // conversions are not accepted by the compiler. Applying a cast to
61 // an oop will cause the best matched conversion operator to be
62 // invoked returning the underlying oopDesc* type if appropriate.
63 // No copy constructors, explicit user conversions or operators of
64 // numerical type should be defined within the oop class. Most C++
65 // compilers will issue a compile time error concerning the overloading
66 // ambiguity between operators of numerical and pointer types. If
67 // a conversion to or from an oop to a numerical type is needed,
68 // use the inline template methods, cast_*_oop, defined below.
69 //
70 // Converting NULL to oop to Handle implicit is no longer accepted by the
71 // compiler because there are too many steps in the conversion. Use Handle()
72 // instead, which generates less code anyway.
73
74 class Thread;
75 class oopDesc;
76
77 extern "C" bool CheckUnhandledOops;
78
79 class oop {
80 oopDesc* _o;
81
82 void register_oop();
83 void unregister_oop();
84
85 void register_if_checking() {
86 if (CheckUnhandledOops) register_oop();
87 }
88
89 public:
90 oop() : _o(nullptr) { register_if_checking(); }
91 oop(const oop& o) : _o(o._o) { register_if_checking(); }
92 oop(oopDesc* o) : _o(o) { register_if_checking(); }
93 ~oop() {
94 if (CheckUnhandledOops) unregister_oop();
95 }
96
97 oopDesc* obj() const { return _o; }
98 oopDesc* operator->() const { return _o; }
99 operator oopDesc* () const { return _o; }
100
101 bool operator==(const oop& o) const { return _o == o._o; }
102 bool operator!=(const oop& o) const { return _o != o._o; }
103
104 bool operator==(std::nullptr_t) const { return _o == nullptr; }
105 bool operator!=(std::nullptr_t) const { return _o != nullptr; }
106
107 oop& operator=(const oop& o) { _o = o._o; return *this; }
108 };
109
110 template<>
111 struct PrimitiveConversions::Translate<oop> : public TrueType {
112 typedef oop Value;
113 typedef oopDesc* Decayed;
114
115 static Decayed decay(Value x) { return x.obj(); }
116 static Value recover(Decayed x) { return oop(x); }
117 };
118
119 #define DEF_OOP(type) \
120 class type##OopDesc; \
121 class type##Oop : public oop { \
122 public: \
123 type##Oop() : oop() {} \
124 type##Oop(const type##Oop& o) : oop(o) {} \
125 type##Oop(const oop& o) : oop(o) {} \
126 type##Oop(type##OopDesc* o) : oop((oopDesc*)o) {} \
127 operator type##OopDesc* () const { return (type##OopDesc*)obj(); } \
128 type##OopDesc* operator->() const { \
129 return (type##OopDesc*)obj(); \
130 } \
131 type##Oop& operator=(const type##Oop& o) { \
132 oop::operator=(o); \
133 return *this; \
134 } \
135 }; \
136 \
137 template<> \
138 struct PrimitiveConversions::Translate<type##Oop> : public TrueType { \
139 typedef type##Oop Value; \
140 typedef type##OopDesc* Decayed; \
141 \
142 static Decayed decay(Value x) { return (type##OopDesc*)x.obj(); } \
143 static Value recover(Decayed x) { return type##Oop(x); } \
144 };
145
146 DEF_OOP(instance);
147 DEF_OOP(array);
148 DEF_OOP(objArray);
149 DEF_OOP(typeArray);
150 DEF_OOP(flatArray);
151
152 #endif // CHECK_UNHANDLED_OOPS
153
154 // Cast functions to convert to and from oops.
155 template <typename T> inline oop cast_to_oop(T value) {
156 return (oopDesc*)value;
157 }
158 template <typename T> inline T cast_from_oop(oop o) {
159 return (T)(CHECK_UNHANDLED_OOPS_ONLY((oopDesc*))o);
160 }
161
162 // The metadata hierarchy is separate from the oop hierarchy
163
164 // class MetaspaceObj
165 class ConstMethod;
166 class ConstantPoolCache;
167 class MethodData;
168 // class Metadata
169 class Method;
170 class ConstantPool;
171 // class CHeapObj
172 class CompiledICHolder;
173
174
175 // The klass hierarchy is separate from the oop hierarchy.
176
177 class Klass;
178 class InstanceKlass;
179 class InstanceMirrorKlass;
180 class InstanceClassLoaderKlass;
181 class InstanceRefKlass;
182 class InlineKlass;
183 class ArrayKlass;
184 class ObjArrayKlass;
185 class TypeArrayKlass;
186 class FlatArrayKlass;
187
188 #endif // SHARE_OOPS_OOPSHIERARCHY_HPP