1 /*
2 * Copyright (c) 1999, 2023, 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,
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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 // Cache constant value lookups to ensure that consistent values are observed during compilation.
63 class ConstantValue {
64 private:
65 ciConstant _value;
66 int _off;
67
68 public:
69 ConstantValue() : _value(ciConstant()), _off(0) { }
70 ConstantValue(int off, ciConstant value) : _value(value), _off(off) { }
71
72 int off() const { return _off; }
73 ciConstant value() const { return _value; }
74 };
75
76 GrowableArray<ConstantValue>* _constant_values = nullptr;
77
78 protected:
79 ciObject();
80 ciObject(oop o);
81 ciObject(Handle h);
82 ciObject(ciKlass* klass);
83
84 jobject handle() const { return _handle; }
85 // Get the VM oop that this object holds.
86 oop get_oop() const;
87
88 // Virtual behavior of the print() method.
89 virtual void print_impl(outputStream* st) {}
90
91 virtual const char* type_string() { return "ciObject"; }
92
93 public:
94 // The klass of this ciObject.
95 ciKlass* klass();
96
97 // Are two ciObjects equal?
98 bool equals(ciObject* obj);
99
100 // A hash value for the convenience of compilers.
101 uint hash();
102
103 // Tells if this oop should be made a constant.
104 bool should_be_constant();
105
106 // The address which the compiler should embed into the
107 // generated code to represent this oop. This address
108 // is not the true address of the oop -- it will get patched
109 // during nmethod creation.
110 //
111 // Usage note: no address arithmetic allowed. Oop must
112 // be registered with the oopRecorder.
113 jobject constant_encoding();
114
115 // Access to the constant value cache
116 ciConstant check_constant_value_cache(int off, BasicType bt);
117 void add_to_constant_value_cache(int off, ciConstant val);
118
119 virtual bool is_object() const { return true; }
120
121 // What kind of ciObject is this?
122 virtual bool is_null_object() const { return false; }
123 virtual bool is_call_site() const { return false; }
124 virtual bool is_instance() { return false; }
125 virtual bool is_member_name() const { return false; }
126 virtual bool is_method_handle() const { return false; }
127 virtual bool is_method_type() const { return false; }
128 virtual bool is_array() { return false; }
129 virtual bool is_obj_array() { return false; }
130 virtual bool is_type_array() { return false; }
131 virtual bool is_native_entry_point()const { return false; }
132
133 // Is this a type or value which has no associated class?
134 // It is true of primitive types and null objects.
135 virtual bool is_classless() const { return false; }
136 virtual void dump_replay_data(outputStream* st) { /* do nothing */ }
137
138 // Note: some ciObjects refer to oops which have yet to be created.
139 // We refer to these as "unloaded". Specifically, there are
140 // unloaded instances of java.lang.Class,
141 // java.lang.invoke.MethodHandle, and java.lang.invoke.MethodType.
142 // By convention the ciNullObject is considered loaded, and
143 // primitive types are considered loaded.
144 bool is_loaded() const {
145 return handle() != nullptr || is_classless();
146 }
147
148 // Subclass casting with assertions.
149 ciNullObject* as_null_object() {
150 assert(is_null_object(), "bad cast");
151 return (ciNullObject*)this;
152 }
153 ciCallSite* as_call_site() {
154 assert(is_call_site(), "bad cast");
155 return (ciCallSite*)this;
156 }
157 ciInstance* as_instance() {
158 assert(is_instance(), "bad cast");
159 return (ciInstance*)this;
160 }
161 ciMemberName* as_member_name() {
162 assert(is_member_name(), "bad cast");
163 return (ciMemberName*)this;
164 }
165 ciMethodHandle* as_method_handle() {
166 assert(is_method_handle(), "bad cast");
167 return (ciMethodHandle*)this;
168 }
169 ciMethodType* as_method_type() {
170 assert(is_method_type(), "bad cast");
171 return (ciMethodType*)this;
172 }
173 ciArray* as_array() {
174 assert(is_array(), "bad cast");
175 return (ciArray*)this;
176 }
177 ciObjArray* as_obj_array() {
178 assert(is_obj_array(), "bad cast");
179 return (ciObjArray*)this;
180 }
181 ciTypeArray* as_type_array() {
182 assert(is_type_array(), "bad cast");
183 return (ciTypeArray*)this;
184 }
185
186 // Print debugging output about this ciObject.
187 void print(outputStream* st);
188 void print() { print(tty); } // GDB cannot handle default arguments
189
190 // Print debugging output about the oop this ciObject represents.
191 void print_oop(outputStream* st = tty);
192 };
193
194 #endif // SHARE_CI_CIOBJECT_HPP