1 /*
2 * Copyright (c) 1999, 2026, 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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24
25 #ifndef SHARE_CI_CIOBJECT_HPP
26 #define SHARE_CI_CIOBJECT_HPP
27
28 #include "ci/ciBaseObject.hpp"
29 #include "ci/ciClassList.hpp"
30 #include "ci/ciConstant.hpp"
31 #include "runtime/handles.hpp"
32 #include "utilities/growableArray.hpp"
33
34 // ciObject
35 //
36 // This class represents an oop in the HotSpot virtual machine.
37 // Its subclasses are structured in a hierarchy which mirrors
38 // an aggregate of the VM's oop and klass hierarchies (see
39 // oopHierarchy.hpp). Each instance of ciObject holds a handle
40 // to a corresponding oop on the VM side and provides routines
41 // for accessing the information in its oop. By using the ciObject
42 // hierarchy for accessing oops in the VM, the compiler ensures
43 // that it is safe with respect to garbage collection; that is,
44 // GC and compilation can proceed independently without
45 // interference.
46 //
47 // Within the VM, the oop and klass hierarchies are separate.
48 // The compiler interface does not preserve this separation --
49 // the distinction between `Klass*' and `Klass' are not
50 // reflected in the interface and instead the Klass hierarchy
51 // is directly modeled as the subclasses of ciKlass.
52 class ciObject : public ciBaseObject {
53 CI_PACKAGE_ACCESS
54 friend class ciEnv;
55
56 private:
57 // A JNI handle referring to an oop in the VM. This
58 // handle may, in a small set of cases, correctly be null.
59 jobject _handle;
60 ciKlass* _klass;
61
62 protected:
63 // Cache constant value lookups to ensure that consistent values are observed during compilation.
64 class ConstantValue {
65 private:
66 ciConstant _value;
67 int _off;
68
69 public:
70 ConstantValue() : _value(ciConstant()), _off(0) { }
71 ConstantValue(int off, ciConstant value) : _value(value), _off(off) { }
72
73 int off() const { return _off; }
74 ciConstant value() const { return _value; }
75 };
76
77 private:
78 GrowableArray<ConstantValue>* _constant_values = nullptr;
79
80 protected:
81 ciObject();
82 ciObject(oop o);
83 ciObject(Handle h);
84 ciObject(ciKlass* klass);
85
86 jobject handle() const { return _handle; }
87 // Get the VM oop that this object holds.
88 oop get_oop() const;
89
90 // Virtual behavior of the print() method.
91 virtual void print_impl(outputStream* st) {}
92
93 virtual const char* type_string() { return "ciObject"; }
94
95 public:
96 // The klass of this ciObject.
97 ciKlass* klass();
98
99 // Are two ciObjects equal?
100 bool equals(ciObject* obj);
101
102 // A hash value for the convenience of compilers.
103 uint hash();
104
105 // Tells if this oop should be made a constant.
106 bool should_be_constant();
107
108 // The address which the compiler should embed into the
109 // generated code to represent this oop. This address
110 // is not the true address of the oop -- it will get patched
111 // during nmethod creation.
112 //
113 // Usage note: no address arithmetic allowed. Oop must
114 // be registered with the oopRecorder.
115 jobject constant_encoding();
116
117 // Access to the constant value cache
118 ciConstant check_constant_value_cache(int off, BasicType bt);
119 void add_to_constant_value_cache(int off, ciConstant val);
120
121 virtual bool is_object() const { return true; }
122
123 // What kind of ciObject is this?
124 virtual bool is_null_object() const { return false; }
125 virtual bool is_call_site() const { return false; }
126 virtual bool is_instance() { return false; }
127 virtual bool is_member_name() const { return false; }
128 virtual bool is_method_handle() const { return false; }
129 virtual bool is_method_type() const { return false; }
130 virtual bool is_array() { return false; }
131 virtual bool is_obj_array() { return false; }
132 virtual bool is_type_array() { return false; }
133 virtual bool is_flat_array() const { return false; }
134 virtual bool is_native_entry_point()const { return false; }
135
136 // Is this a type or value which has no associated class?
137 // It is true of primitive types and null objects.
138 virtual bool is_classless() const { return false; }
139 virtual void dump_replay_data(outputStream* st) { /* do nothing */ }
140
141 // Note: some ciObjects refer to oops which have yet to be created.
142 // We refer to these as "unloaded". Specifically, there are
143 // unloaded instances of java.lang.Class,
144 // java.lang.invoke.MethodHandle, and java.lang.invoke.MethodType.
145 // By convention the ciNullObject is considered loaded, and
146 // primitive types are considered loaded.
147 bool is_loaded() const {
148 return handle() != nullptr || is_classless();
149 }
150
151 // Subclass casting with assertions.
152 ciNullObject* as_null_object() {
153 assert(is_null_object(), "bad cast");
154 return (ciNullObject*)this;
155 }
156 ciCallSite* as_call_site() {
157 assert(is_call_site(), "bad cast");
158 return (ciCallSite*)this;
159 }
160 ciInstance* as_instance() {
161 assert(is_instance(), "bad cast");
162 return (ciInstance*)this;
163 }
164 ciMemberName* as_member_name() {
165 assert(is_member_name(), "bad cast");
166 return (ciMemberName*)this;
167 }
168 ciMethodHandle* as_method_handle() {
169 assert(is_method_handle(), "bad cast");
170 return (ciMethodHandle*)this;
171 }
172 ciMethodType* as_method_type() {
173 assert(is_method_type(), "bad cast");
174 return (ciMethodType*)this;
175 }
176 ciArray* as_array() {
177 assert(is_array(), "bad cast");
178 return (ciArray*)this;
179 }
180 ciObjArray* as_obj_array() {
181 assert(is_obj_array(), "bad cast");
182 return (ciObjArray*)this;
183 }
184 ciTypeArray* as_type_array() {
185 assert(is_type_array(), "bad cast");
186 return (ciTypeArray*)this;
187 }
188 ciFlatArray* as_flat_array() {
189 assert(is_flat_array(), "bad cast");
190 return (ciFlatArray*)this;
191 }
192
193 // Print debugging output about this ciObject.
194 void print(outputStream* st);
195 void print() { print(tty); } // GDB cannot handle default arguments
196
197 // Print debugging output about the oop this ciObject represents.
198 void print_oop(outputStream* st = tty);
199 };
200
201 #endif // SHARE_CI_CIOBJECT_HPP