Mercurial > hg > graal-compiler
annotate src/share/vm/classfile/placeholders.hpp @ 1755:8e5955ddf8e4
6978300: G1: debug builds crash if ParallelGCThreads==0
Reviewed-by: tonyp, ysr
author | jcoomes |
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date | Wed, 25 Aug 2010 14:39:55 -0700 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 2003, 2007, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 class PlaceholderEntry; | |
26 | |
27 // Placeholder objects. These represent classes currently | |
28 // being loaded, as well as arrays of primitives. | |
29 // | |
30 | |
31 class PlaceholderTable : public TwoOopHashtable { | |
32 friend class VMStructs; | |
33 | |
34 public: | |
35 PlaceholderTable(int table_size); | |
36 | |
37 PlaceholderEntry* new_entry(int hash, symbolOop name, oop loader, bool havesupername, symbolOop supername); | |
38 | |
39 PlaceholderEntry* bucket(int i) { | |
40 return (PlaceholderEntry*)Hashtable::bucket(i); | |
41 } | |
42 | |
43 PlaceholderEntry** bucket_addr(int i) { | |
44 return (PlaceholderEntry**)Hashtable::bucket_addr(i); | |
45 } | |
46 | |
47 void add_entry(int index, PlaceholderEntry* new_entry) { | |
48 Hashtable::add_entry(index, (HashtableEntry*)new_entry); | |
49 } | |
50 | |
51 void add_entry(int index, unsigned int hash, symbolHandle name, | |
52 Handle loader, bool havesupername, symbolHandle supername); | |
53 | |
54 // This returns a symbolOop to match type for SystemDictionary | |
55 symbolOop find_entry(int index, unsigned int hash, | |
56 symbolHandle name, Handle loader); | |
57 | |
58 PlaceholderEntry* get_entry(int index, unsigned int hash, | |
59 symbolHandle name, Handle loader); | |
60 | |
61 // caller to create a placeholder entry must enumerate an action | |
62 // caller claims ownership of that action | |
63 // For parallel classloading: | |
64 // multiple LOAD_INSTANCE threads can proceed in parallel | |
65 // multiple LOAD_SUPER threads can proceed in parallel | |
66 // LOAD_SUPER needed to check for class circularity | |
67 // DEFINE_CLASS: ultimately define class must be single threaded | |
68 // on a class/classloader basis | |
69 // so the head of that queue owns the token | |
70 // and the rest of the threads return the result the first thread gets | |
71 enum classloadAction { | |
72 LOAD_INSTANCE = 1, // calling load_instance_class | |
73 LOAD_SUPER = 2, // loading superclass for this class | |
74 DEFINE_CLASS = 3 // find_or_define class | |
75 }; | |
76 | |
77 // find_and_add returns probe pointer - old or new | |
78 // If no entry exists, add a placeholder entry and push SeenThread | |
79 // If entry exists, reuse entry and push SeenThread for classloadAction | |
80 PlaceholderEntry* find_and_add(int index, unsigned int hash, | |
81 symbolHandle name, Handle loader, | |
82 classloadAction action, symbolHandle supername, | |
83 Thread* thread); | |
84 | |
85 void remove_entry(int index, unsigned int hash, | |
86 symbolHandle name, Handle loader); | |
87 | |
88 // Remove placeholder information | |
89 void find_and_remove(int index, unsigned int hash, | |
90 symbolHandle name, Handle loader, Thread* thread); | |
91 | |
92 // GC support. | |
93 void oops_do(OopClosure* f); | |
94 | |
95 // JVMTI support | |
96 void entries_do(void f(symbolOop, oop)); | |
97 | |
98 #ifndef PRODUCT | |
99 void print(); | |
100 #endif | |
101 void verify(); | |
102 }; | |
103 | |
104 // SeenThread objects represent list of threads that are | |
105 // currently performing a load action on a class. | |
106 // For class circularity, set before loading a superclass. | |
107 // For bootclasssearchpath, set before calling load_instance_class. | |
108 // Defining must be single threaded on a class/classloader basis | |
109 // For DEFINE_CLASS, the head of the queue owns the | |
110 // define token and the rest of the threads wait to return the | |
111 // result the first thread gets. | |
112 class SeenThread: public CHeapObj { | |
113 private: | |
114 Thread *_thread; | |
115 SeenThread* _stnext; | |
116 SeenThread* _stprev; | |
117 public: | |
118 SeenThread(Thread *thread) { | |
119 _thread = thread; | |
120 _stnext = NULL; | |
121 _stprev = NULL; | |
122 } | |
123 Thread* thread() const { return _thread;} | |
124 void set_thread(Thread *thread) { _thread = thread; } | |
125 | |
126 SeenThread* next() const { return _stnext;} | |
127 void set_next(SeenThread *seen) { _stnext = seen; } | |
128 void set_prev(SeenThread *seen) { _stprev = seen; } | |
129 | |
130 #ifndef PRODUCT | |
131 void printActionQ() { | |
132 SeenThread* seen = this; | |
133 while (seen != NULL) { | |
134 seen->thread()->print_value(); | |
135 tty->print(", "); | |
136 seen = seen->next(); | |
137 } | |
138 } | |
139 #endif // PRODUCT | |
140 }; | |
141 | |
142 // Placeholder objects represent classes currently being loaded. | |
143 // All threads examining the placeholder table must hold the | |
144 // SystemDictionary_lock, so we don't need special precautions | |
145 // on store ordering here. | |
146 // The system dictionary is the only user of this class. | |
147 | |
148 class PlaceholderEntry : public HashtableEntry { | |
149 friend class VMStructs; | |
150 | |
151 | |
152 private: | |
153 oop _loader; // initiating loader | |
154 bool _havesupername; // distinguish between null supername, and unknown | |
155 symbolOop _supername; | |
156 Thread* _definer; // owner of define token | |
157 klassOop _instanceKlass; // instanceKlass from successful define | |
158 SeenThread* _superThreadQ; // doubly-linked queue of Threads loading a superclass for this class | |
159 SeenThread* _loadInstanceThreadQ; // loadInstance thread | |
160 // can be multiple threads if classloader object lock broken by application | |
161 // or if classloader supports parallel classloading | |
162 | |
163 SeenThread* _defineThreadQ; // queue of Threads trying to define this class | |
164 // including _definer | |
165 // _definer owns token | |
166 // queue waits for and returns results from _definer | |
167 | |
168 public: | |
169 // Simple accessors, used only by SystemDictionary | |
170 symbolOop klass() const { return (symbolOop)literal(); } | |
171 symbolOop* klass_addr() { return (symbolOop*)literal_addr(); } | |
172 | |
173 oop loader() const { return _loader; } | |
174 void set_loader(oop loader) { _loader = loader; } | |
175 oop* loader_addr() { return &_loader; } | |
176 | |
177 bool havesupername() const { return _havesupername; } | |
178 void set_havesupername(bool havesupername) { _havesupername = havesupername; } | |
179 | |
180 symbolOop supername() const { return _supername; } | |
181 void set_supername(symbolOop supername) { _supername = supername; } | |
182 symbolOop* supername_addr() { return &_supername; } | |
183 | |
184 Thread* definer() const {return _definer; } | |
185 void set_definer(Thread* definer) { _definer = definer; } | |
186 | |
187 klassOop instanceKlass() const {return _instanceKlass; } | |
188 void set_instanceKlass(klassOop instanceKlass) { _instanceKlass = instanceKlass; } | |
189 klassOop* instanceKlass_addr() { return &_instanceKlass; } | |
190 | |
191 SeenThread* superThreadQ() const { return _superThreadQ; } | |
192 void set_superThreadQ(SeenThread* SeenThread) { _superThreadQ = SeenThread; } | |
193 | |
194 SeenThread* loadInstanceThreadQ() const { return _loadInstanceThreadQ; } | |
195 void set_loadInstanceThreadQ(SeenThread* SeenThread) { _loadInstanceThreadQ = SeenThread; } | |
196 | |
197 SeenThread* defineThreadQ() const { return _defineThreadQ; } | |
198 void set_defineThreadQ(SeenThread* SeenThread) { _defineThreadQ = SeenThread; } | |
199 | |
200 PlaceholderEntry* next() const { | |
201 return (PlaceholderEntry*)HashtableEntry::next(); | |
202 } | |
203 | |
204 PlaceholderEntry** next_addr() { | |
205 return (PlaceholderEntry**)HashtableEntry::next_addr(); | |
206 } | |
207 | |
208 // Test for equality | |
209 // Entries are unique for class/classloader name pair | |
210 bool equals(symbolOop class_name, oop class_loader) const { | |
211 return (klass() == class_name && loader() == class_loader); | |
212 } | |
213 | |
214 SeenThread* actionToQueue(PlaceholderTable::classloadAction action) { | |
215 SeenThread* queuehead; | |
216 switch (action) { | |
217 case PlaceholderTable::LOAD_INSTANCE: | |
218 queuehead = _loadInstanceThreadQ; | |
219 break; | |
220 case PlaceholderTable::LOAD_SUPER: | |
221 queuehead = _superThreadQ; | |
222 break; | |
223 case PlaceholderTable::DEFINE_CLASS: | |
224 queuehead = _defineThreadQ; | |
225 break; | |
226 default: Unimplemented(); | |
227 } | |
228 return queuehead; | |
229 } | |
230 | |
231 void set_threadQ(SeenThread* seenthread, PlaceholderTable::classloadAction action) { | |
232 switch (action) { | |
233 case PlaceholderTable::LOAD_INSTANCE: | |
234 _loadInstanceThreadQ = seenthread; | |
235 break; | |
236 case PlaceholderTable::LOAD_SUPER: | |
237 _superThreadQ = seenthread; | |
238 break; | |
239 case PlaceholderTable::DEFINE_CLASS: | |
240 _defineThreadQ = seenthread; | |
241 break; | |
242 default: Unimplemented(); | |
243 } | |
244 return; | |
245 } | |
246 | |
247 bool super_load_in_progress() { | |
248 return (_superThreadQ != NULL); | |
249 } | |
250 | |
251 bool instance_load_in_progress() { | |
252 return (_loadInstanceThreadQ != NULL); | |
253 } | |
254 | |
255 bool define_class_in_progress() { | |
256 return (_defineThreadQ != NULL); | |
257 } | |
258 | |
259 // Doubly-linked list of Threads per action for class/classloader pair | |
260 // Class circularity support: links in thread before loading superclass | |
261 // bootstrapsearchpath support: links in a thread before load_instance_class | |
262 // definers: use as queue of define requestors, including owner of | |
263 // define token. Appends for debugging of requestor order | |
264 void add_seen_thread(Thread* thread, PlaceholderTable::classloadAction action) { | |
265 assert_lock_strong(SystemDictionary_lock); | |
266 SeenThread* threadEntry = new SeenThread(thread); | |
267 SeenThread* seen = actionToQueue(action); | |
268 | |
269 if (seen == NULL) { | |
270 set_threadQ(threadEntry, action); | |
271 return; | |
272 } | |
273 SeenThread* next; | |
274 while ((next = seen->next()) != NULL) { | |
275 seen = next; | |
276 } | |
277 seen->set_next(threadEntry); | |
278 threadEntry->set_prev(seen); | |
279 return; | |
280 } | |
281 | |
282 bool check_seen_thread(Thread* thread, PlaceholderTable::classloadAction action) { | |
283 assert_lock_strong(SystemDictionary_lock); | |
284 SeenThread* threadQ = actionToQueue(action); | |
285 SeenThread* seen = threadQ; | |
286 while (seen) { | |
287 if (thread == seen->thread()) { | |
288 return true; | |
289 } | |
290 seen = seen->next(); | |
291 } | |
292 return false; | |
293 } | |
294 | |
295 // returns true if seenthreadQ is now empty | |
296 // Note, caller must ensure probe still exists while holding | |
297 // SystemDictionary_lock | |
298 // ignores if cleanup has already been done | |
299 // if found, deletes SeenThread | |
300 bool remove_seen_thread(Thread* thread, PlaceholderTable::classloadAction action) { | |
301 assert_lock_strong(SystemDictionary_lock); | |
302 SeenThread* threadQ = actionToQueue(action); | |
303 SeenThread* seen = threadQ; | |
304 SeenThread* prev = NULL; | |
305 while (seen) { | |
306 if (thread == seen->thread()) { | |
307 if (prev) { | |
308 prev->set_next(seen->next()); | |
309 } else { | |
310 set_threadQ(seen->next(), action); | |
311 } | |
312 if (seen->next()) { | |
313 seen->next()->set_prev(prev); | |
314 } | |
315 delete seen; | |
316 break; | |
317 } | |
318 prev = seen; | |
319 seen = seen->next(); | |
320 } | |
321 return (actionToQueue(action) == NULL); | |
322 } | |
323 | |
324 // GC support | |
325 // Applies "f->do_oop" to all root oops in the placeholder table. | |
326 void oops_do(OopClosure* blk); | |
327 | |
328 // Print method doesn't append a cr | |
329 void print() const PRODUCT_RETURN; | |
330 void verify() const; | |
331 }; |