1 /*
2 * Copyright (c) 1997, 2018, 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
6 * under the terms of the GNU General Public License version 2 only, as
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.
18 *
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
21 * questions.
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23 */
24
25 #ifndef SHARE_VM_OOPS_OOPSHIERARCHY_HPP
26 #define SHARE_VM_OOPS_OOPSHIERARCHY_HPP
27
28 #include "metaprogramming/integralConstant.hpp"
29 #include "metaprogramming/primitiveConversions.hpp"
30 #include "runtime/globals.hpp"
31 #include "utilities/globalDefinitions.hpp"
32 #include "utilities/macros.hpp"
33
34 // OBJECT hierarchy
35 // This hierarchy is a representation hierarchy, i.e. if A is a superclass
36 // of B, A's representation is a prefix of B's representation.
37
38 // Compressed oop class
39 class narrowOop {
40 public:
41 typedef uint32_t PrimitiveType;
42
43 private:
44 PrimitiveType _value;
45
46 public:
47 narrowOop() : _value(0) {}
48 narrowOop(const narrowOop& o) : _value(o._value) {}
49 narrowOop(const volatile narrowOop& o) : _value(o._value) {}
50 narrowOop(const PrimitiveType value) : _value(value) {}
51
52 PrimitiveType value() { return _value; }
53
54 bool operator==(const narrowOop o) const { return _value == o._value; }
55 bool operator!=(const narrowOop o) const { return _value != o._value; }
56
57 narrowOop& operator=(const narrowOop o) { _value = o._value; return *this; }
58
59 operator PrimitiveType () const { return _value; }
60 };
61
62 template<>
63 struct PrimitiveConversions::Translate<narrowOop> : public TrueType {
64 typedef narrowOop Value;
65 typedef narrowOop::PrimitiveType Decayed;
66
67 static Decayed decay(Value x) { return x.value(); }
68 static Value recover(Decayed x) { return narrowOop(x); }
69 };
70
71 // If compressed klass pointers then use narrowKlass.
72 typedef juint narrowKlass;
73
74 typedef void* OopOrNarrowOopStar;
75 typedef class markOopDesc* markOop;
76
77 // Because oop and its subclasses <type>Oop are class types, arbitrary
78 // conversions are not accepted by the compiler. Applying a cast to
79 // an oop will cause the best matched conversion operator to be
80 // invoked returning the underlying oopDesc* type if appropriate.
81 // No copy constructors, explicit user conversions or operators of
82 // numerical type should be defined within the oop class. Most C++
83 // compilers will issue a compile time error concerning the overloading
84 // ambiguity between operators of numerical and pointer types. If
85 // a conversion to or from an oop to a numerical type is needed,
86 // use the inline template methods, cast_*_oop, defined below.
87 //
88 // Converting NULL to oop to Handle implicit is no longer accepted by the
89 // compiler because there are too many steps in the conversion. Use Handle()
90 // instead, which generates less code anyway.
91
92 class Thread;
93 class PromotedObject;
94
95
96 class oop {
97 oopDesc* _o;
98
99 #ifdef CHECK_UNHANDLED_OOPS
100 void register_oop();
101 void unregister_oop();
102 #endif
103
104 // friend class markOop;
105 public:
106 void set_obj(const void* p) {
107 raw_set_obj(p);
108 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) register_oop();)
109 }
110 void raw_set_obj(const void* p) { _o = (oopDesc*)p; }
111
112 oop() { set_obj(NULL); }
113 oop(const oop& o) { set_obj(o.obj()); }
114 oop(const volatile oop& o) { set_obj(o.obj()); }
115 oop(const void* p) { set_obj(p); }
116 ~oop() {
117 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) unregister_oop();)
118 }
119
120 oopDesc* obj() const volatile { return _o; }
121
122 // General access
123 oopDesc* operator->() const { return obj(); }
124 bool operator==(const oop o) const { return obj() == o.obj(); }
125 bool operator==(void *p) const { return obj() == p; }
126 bool operator!=(const volatile oop o) const { return obj() != o.obj(); }
127 bool operator!=(void *p) const { return obj() != p; }
128
129 // Assignment
130 oop& operator=(const oop& o) { _o = o.obj(); return *this; }
131 volatile oop& operator=(const oop& o) volatile { _o = o.obj(); return *this; }
132 volatile oop& operator=(const volatile oop& o) volatile { _o = o.obj(); return *this; }
133
134 // Explict user conversions
135 operator void* () const { return (void *)obj(); }
136 #ifndef SOLARIS
137 operator void* () const volatile { return (void *)obj(); }
138 #endif
139 operator HeapWord* () const { return (HeapWord*)obj(); }
140 operator oopDesc* () const volatile { return obj(); }
141 operator intptr_t* () const { return (intptr_t*)obj(); }
142 operator PromotedObject* () const { return (PromotedObject*)obj(); }
143 operator markOop () const volatile { return markOop(obj()); }
144 operator address () const { return (address)obj(); }
145
146 // from javaCalls.cpp
147 operator jobject () const { return (jobject)obj(); }
148
149 // from parNewGeneration and other things that want to get to the end of
150 // an oop for stuff (like ObjArrayKlass.cpp)
151 operator oop* () const { return (oop *)obj(); }
152 };
153
154 template<>
155 struct PrimitiveConversions::Translate<oop> : public TrueType {
156 typedef oop Value;
157 typedef oopDesc* Decayed;
158
159 static Decayed decay(Value x) { return x.obj(); }
160 static Value recover(Decayed x) { return oop(x); }
161 };
162
163 #define DEF_OOP(type) \
164 class type##OopDesc; \
165 class type##Oop : public oop { \
166 public: \
167 type##Oop() : oop() {} \
168 type##Oop(const oop& o) : oop(o) {} \
169 type##Oop(const volatile oop& o) : oop(o) {} \
170 type##Oop(const void* p) : oop(p) {} \
171 operator type##OopDesc* () const { return (type##OopDesc*)obj(); } \
172 type##OopDesc* operator->() const { \
173 return (type##OopDesc*)obj(); \
174 } \
175 type##Oop& operator=(const type##Oop& o) { \
176 oop::operator=(o); \
177 return *this; \
178 } \
179 volatile type##Oop& operator=(const type##Oop& o) volatile { \
180 (void)const_cast<oop&>(oop::operator=(o)); \
181 return *this; \
182 } \
183 volatile type##Oop& operator=(const volatile type##Oop& o) volatile {\
184 (void)const_cast<oop&>(oop::operator=(o)); \
185 return *this; \
186 } \
187 }; \
188 \
189 template<> \
190 struct PrimitiveConversions::Translate<type##Oop> : public TrueType { \
191 typedef type##Oop Value; \
192 typedef type##OopDesc* Decayed; \
193 \
194 static Decayed decay(Value x) { return (type##OopDesc*)x.obj(); } \
195 static Value recover(Decayed x) { return type##Oop(x); } \
196 };
197
198 DEF_OOP(instance);
199 DEF_OOP(array);
200 DEF_OOP(objArray);
201 DEF_OOP(typeArray);
202
203 // It is ambiguous C++ behavior to have the oop structure contain explicit
204 // user defined conversions of both numerical and pointer type.
205 // Define inline methods to provide the numerical conversions.
206 template <class T> inline oop cast_to_oop(T value) {
207 return (oop)((void *)(value));
208 }
209 template <class T> inline T cast_from_oop(oop o) {
210 return (T)((void*)o);
211 }
212
213 // The metadata hierarchy is separate from the oop hierarchy
214
215 // class MetaspaceObj
216 class ConstMethod;
217 class ConstantPoolCache;
218 class MethodData;
219 // class Metadata
220 class Method;
221 class ConstantPool;
222 // class CHeapObj
223 class CompiledICHolder;
224
225
226 // The klass hierarchy is separate from the oop hierarchy.
227
228 class Klass;
229 class InstanceKlass;
230 class InstanceMirrorKlass;
231 class InstanceClassLoaderKlass;
232 class InstanceRefKlass;
233 class ArrayKlass;
234 class ObjArrayKlass;
235 class TypeArrayKlass;
236
237 #endif // SHARE_VM_OOPS_OOPSHIERARCHY_HPP