1 /*
2 * Copyright (c) 1999, 2010, 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_CI_CIOBJECT_HPP
26 #define SHARE_VM_CI_CIOBJECT_HPP
27
28 #include "ci/ciClassList.hpp"
29 #include "memory/allocation.hpp"
30 #include "runtime/handles.hpp"
31 #include "runtime/jniHandles.hpp"
32
33 // ciObject
34 //
35 // This class represents an oop in the HotSpot virtual machine.
36 // Its subclasses are structured in a hierarchy which mirrors
37 // an aggregate of the VM's oop and klass hierarchies (see
38 // oopHierarchy.hpp). Each instance of ciObject holds a handle
39 // to a corresponding oop on the VM side and provides routines
40 // for accessing the information in its oop. By using the ciObject
41 // hierarchy for accessing oops in the VM, the compiler ensures
42 // that it is safe with respect to garbage collection; that is,
43 // GC and compilation can proceed independently without
44 // interference.
45 //
46 // Within the VM, the oop and klass hierarchies are separate.
47 // The compiler interface does not preserve this separation --
48 // the distinction between `klassOop' and `Klass' are not
49 // reflected in the interface and instead the Klass hierarchy
50 // is directly modeled as the subclasses of ciKlass.
51 class ciObject : public ResourceObj {
52 CI_PACKAGE_ACCESS
53 friend class ciEnv;
54
55 private:
56 // A JNI handle referring to an oop in the VM. This
57 // handle may, in a small set of cases, correctly be NULL.
58 jobject _handle;
59 ciKlass* _klass;
60 uint _ident;
61
62 enum { FLAG_BITS = 2 };
63 enum {
64 PERM_FLAG = 1,
65 SCAVENGABLE_FLAG = 2
66 };
67 protected:
68 ciObject();
69 ciObject(oop o);
70 ciObject(Handle h);
71 ciObject(ciKlass* klass);
72
73 jobject handle() const { return _handle; }
74 // Get the VM oop that this object holds.
75 oop get_oop() const {
76 assert(_handle != NULL, "null oop");
77 return JNIHandles::resolve_non_null(_handle);
78 }
79
80 void init_flags_from(oop x) {
81 int flags = 0;
82 if (x != NULL) {
83 if (x->is_perm())
84 flags |= PERM_FLAG;
85 if (x->is_scavengable())
86 flags |= SCAVENGABLE_FLAG;
87 }
88 _ident |= flags;
89 }
90
91 // Virtual behavior of the print() method.
92 virtual void print_impl(outputStream* st) {}
93
94 virtual const char* type_string() { return "ciObject"; }
95
96 void set_ident(uint id);
97 public:
98 // The klass of this ciObject.
99 ciKlass* klass();
100
101 // A number unique to this object.
102 uint ident();
103
104 // Are two ciObjects equal?
105 bool equals(ciObject* obj);
106
107 // A hash value for the convenience of compilers.
108 int hash();
109
110 // Tells if this oop has an encoding as a constant.
111 // True if is_scavengable is false.
112 // Also true if ScavengeRootsInCode is non-zero.
113 // If it does not have an encoding, the compiler is responsible for
114 // making other arrangements for dealing with the oop.
115 // See ciEnv::make_array
116 bool can_be_constant();
117
118 // Tells if this oop should be made a constant.
119 // True if is_scavengable is false or ScavengeRootsInCode > 1.
120 bool should_be_constant();
121
122 // Is this object guaranteed to be in the permanent part of the heap?
123 // If so, CollectedHeap::can_elide_permanent_oop_store_barriers is relevant.
124 // If the answer is false, no guarantees are made.
125 bool is_perm() { return (_ident & PERM_FLAG) != 0; }
126
127 // Might this object possibly move during a scavenge operation?
128 // If the answer is true and ScavengeRootsInCode==0, the oop cannot be embedded in code.
129 bool is_scavengable() { return (_ident & SCAVENGABLE_FLAG) != 0; }
130
131 // The address which the compiler should embed into the
132 // generated code to represent this oop. This address
133 // is not the true address of the oop -- it will get patched
134 // during nmethod creation.
135 //
136 // Usage note: no address arithmetic allowed. Oop must
137 // be registered with the oopRecorder.
138 jobject constant_encoding();
139
140 // What kind of ciObject is this?
141 virtual bool is_null_object() const { return false; }
142 virtual bool is_call_site() const { return false; }
143 virtual bool is_cpcache() const { return false; }
144 virtual bool is_instance() { return false; }
145 virtual bool is_method() { return false; }
146 virtual bool is_method_data() { return false; }
147 virtual bool is_method_handle() const { return false; }
148 virtual bool is_array() { return false; }
149 virtual bool is_obj_array() { return false; }
150 virtual bool is_type_array() { return false; }
151 virtual bool is_symbol() { return false; }
152 virtual bool is_type() { return false; }
153 virtual bool is_return_address() { return false; }
154 virtual bool is_klass() { return false; }
155 virtual bool is_instance_klass() { return false; }
156 virtual bool is_method_klass() { return false; }
157 virtual bool is_array_klass() { return false; }
158 virtual bool is_obj_array_klass() { return false; }
159 virtual bool is_type_array_klass() { return false; }
160 virtual bool is_symbol_klass() { return false; }
161 virtual bool is_klass_klass() { return false; }
162 virtual bool is_instance_klass_klass() { return false; }
163 virtual bool is_array_klass_klass() { return false; }
164 virtual bool is_obj_array_klass_klass() { return false; }
165 virtual bool is_type_array_klass_klass() { return false; }
166
167 // Is this a type or value which has no associated class?
168 // It is true of primitive types and null objects.
169 virtual bool is_classless() const { return false; }
170
171 // Is this ciObject a Java Language Object? That is,
172 // is the ciObject an instance or an array
173 virtual bool is_java_object() { return false; }
174
175 // Does this ciObject represent a Java Language class?
176 // That is, is the ciObject an instanceKlass or arrayKlass?
177 virtual bool is_java_klass() { return false; }
178
179 // Is this ciObject the ciInstanceKlass representing
180 // java.lang.Object()?
181 virtual bool is_java_lang_Object() { return false; }
182
183 // Does this ciObject refer to a real oop in the VM?
184 //
185 // Note: some ciObjects refer to oops which have yet to be
186 // created. We refer to these as "unloaded". Specifically,
187 // there are unloaded ciMethods, ciObjArrayKlasses, and
188 // ciInstanceKlasses. By convention the ciNullObject is
189 // considered loaded, and primitive types are considered loaded.
190 bool is_loaded() const {
191 return handle() != NULL || is_classless();
192 }
193
194 // Subclass casting with assertions.
195 ciNullObject* as_null_object() {
196 assert(is_null_object(), "bad cast");
197 return (ciNullObject*)this;
198 }
199 ciCallSite* as_call_site() {
200 assert(is_call_site(), "bad cast");
201 return (ciCallSite*) this;
202 }
203 ciCPCache* as_cpcache() {
204 assert(is_cpcache(), "bad cast");
205 return (ciCPCache*) this;
206 }
207 ciInstance* as_instance() {
208 assert(is_instance(), "bad cast");
209 return (ciInstance*)this;
210 }
211 ciMethod* as_method() {
212 assert(is_method(), "bad cast");
213 return (ciMethod*)this;
214 }
215 ciMethodData* as_method_data() {
216 assert(is_method_data(), "bad cast");
217 return (ciMethodData*)this;
218 }
219 ciMethodHandle* as_method_handle() {
220 assert(is_method_handle(), "bad cast");
221 return (ciMethodHandle*) this;
222 }
223 ciArray* as_array() {
224 assert(is_array(), "bad cast");
225 return (ciArray*)this;
226 }
227 ciObjArray* as_obj_array() {
228 assert(is_obj_array(), "bad cast");
229 return (ciObjArray*)this;
230 }
231 ciTypeArray* as_type_array() {
232 assert(is_type_array(), "bad cast");
233 return (ciTypeArray*)this;
234 }
235 ciSymbol* as_symbol() {
236 assert(is_symbol(), "bad cast");
237 return (ciSymbol*)this;
238 }
239 ciType* as_type() {
240 assert(is_type(), "bad cast");
241 return (ciType*)this;
242 }
243 ciReturnAddress* as_return_address() {
244 assert(is_return_address(), "bad cast");
245 return (ciReturnAddress*)this;
246 }
247 ciKlass* as_klass() {
248 assert(is_klass(), "bad cast");
249 return (ciKlass*)this;
250 }
251 ciInstanceKlass* as_instance_klass() {
252 assert(is_instance_klass(), "bad cast");
253 return (ciInstanceKlass*)this;
254 }
255 ciMethodKlass* as_method_klass() {
256 assert(is_method_klass(), "bad cast");
257 return (ciMethodKlass*)this;
258 }
259 ciArrayKlass* as_array_klass() {
260 assert(is_array_klass(), "bad cast");
261 return (ciArrayKlass*)this;
262 }
263 ciObjArrayKlass* as_obj_array_klass() {
264 assert(is_obj_array_klass(), "bad cast");
265 return (ciObjArrayKlass*)this;
266 }
267 ciTypeArrayKlass* as_type_array_klass() {
268 assert(is_type_array_klass(), "bad cast");
269 return (ciTypeArrayKlass*)this;
270 }
271 ciSymbolKlass* as_symbol_klass() {
272 assert(is_symbol_klass(), "bad cast");
273 return (ciSymbolKlass*)this;
274 }
275 ciKlassKlass* as_klass_klass() {
276 assert(is_klass_klass(), "bad cast");
277 return (ciKlassKlass*)this;
278 }
279 ciInstanceKlassKlass* as_instance_klass_klass() {
280 assert(is_instance_klass_klass(), "bad cast");
281 return (ciInstanceKlassKlass*)this;
282 }
283 ciArrayKlassKlass* as_array_klass_klass() {
284 assert(is_array_klass_klass(), "bad cast");
285 return (ciArrayKlassKlass*)this;
286 }
287 ciObjArrayKlassKlass* as_obj_array_klass_klass() {
288 assert(is_obj_array_klass_klass(), "bad cast");
289 return (ciObjArrayKlassKlass*)this;
290 }
291 ciTypeArrayKlassKlass* as_type_array_klass_klass() {
292 assert(is_type_array_klass_klass(), "bad cast");
293 return (ciTypeArrayKlassKlass*)this;
294 }
295
296 // Print debugging output about this ciObject.
297 void print(outputStream* st = tty);
298
299 // Print debugging output about the oop this ciObject represents.
300 void print_oop(outputStream* st = tty);
301 };
302
303 #endif // SHARE_VM_CI_CIOBJECT_HPP