Mercurial > hg > truffle
annotate src/share/vm/classfile/placeholders.hpp @ 2129:8f8dfba37802
6994753: Implement optional hook to a Java method at VM startup.
Reviewed-by: mchung, acorn
| author | kevinw |
|---|---|
| date | Wed, 12 Jan 2011 15:44:16 +0000 |
| parents | c760f78e0a53 |
| children | 3582bf76420e |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 1972 | 2 * Copyright (c) 2003, 2010, 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 | |
| 1972 | 25 #ifndef SHARE_VM_CLASSFILE_PLACEHOLDERS_HPP |
| 26 #define SHARE_VM_CLASSFILE_PLACEHOLDERS_HPP | |
| 27 | |
|
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28 #include "runtime/thread.hpp" |
| 1972 | 29 #include "utilities/hashtable.hpp" |
| 30 | |
| 0 | 31 class PlaceholderEntry; |
| 32 | |
| 33 // Placeholder objects. These represent classes currently | |
| 34 // being loaded, as well as arrays of primitives. | |
| 35 // | |
| 36 | |
| 37 class PlaceholderTable : public TwoOopHashtable { | |
| 38 friend class VMStructs; | |
| 39 | |
| 40 public: | |
| 41 PlaceholderTable(int table_size); | |
| 42 | |
| 43 PlaceholderEntry* new_entry(int hash, symbolOop name, oop loader, bool havesupername, symbolOop supername); | |
| 44 | |
| 45 PlaceholderEntry* bucket(int i) { | |
| 46 return (PlaceholderEntry*)Hashtable::bucket(i); | |
| 47 } | |
| 48 | |
| 49 PlaceholderEntry** bucket_addr(int i) { | |
| 50 return (PlaceholderEntry**)Hashtable::bucket_addr(i); | |
| 51 } | |
| 52 | |
| 53 void add_entry(int index, PlaceholderEntry* new_entry) { | |
| 54 Hashtable::add_entry(index, (HashtableEntry*)new_entry); | |
| 55 } | |
| 56 | |
| 57 void add_entry(int index, unsigned int hash, symbolHandle name, | |
| 58 Handle loader, bool havesupername, symbolHandle supername); | |
| 59 | |
| 60 // This returns a symbolOop to match type for SystemDictionary | |
| 61 symbolOop find_entry(int index, unsigned int hash, | |
| 62 symbolHandle name, Handle loader); | |
| 63 | |
| 64 PlaceholderEntry* get_entry(int index, unsigned int hash, | |
| 65 symbolHandle name, Handle loader); | |
| 66 | |
| 67 // caller to create a placeholder entry must enumerate an action | |
| 68 // caller claims ownership of that action | |
| 69 // For parallel classloading: | |
| 70 // multiple LOAD_INSTANCE threads can proceed in parallel | |
| 71 // multiple LOAD_SUPER threads can proceed in parallel | |
| 72 // LOAD_SUPER needed to check for class circularity | |
| 73 // DEFINE_CLASS: ultimately define class must be single threaded | |
| 74 // on a class/classloader basis | |
| 75 // so the head of that queue owns the token | |
| 76 // and the rest of the threads return the result the first thread gets | |
| 77 enum classloadAction { | |
| 78 LOAD_INSTANCE = 1, // calling load_instance_class | |
| 79 LOAD_SUPER = 2, // loading superclass for this class | |
| 80 DEFINE_CLASS = 3 // find_or_define class | |
| 81 }; | |
| 82 | |
| 83 // find_and_add returns probe pointer - old or new | |
| 84 // If no entry exists, add a placeholder entry and push SeenThread | |
| 85 // If entry exists, reuse entry and push SeenThread for classloadAction | |
| 86 PlaceholderEntry* find_and_add(int index, unsigned int hash, | |
| 87 symbolHandle name, Handle loader, | |
| 88 classloadAction action, symbolHandle supername, | |
| 89 Thread* thread); | |
| 90 | |
| 91 void remove_entry(int index, unsigned int hash, | |
| 92 symbolHandle name, Handle loader); | |
| 93 | |
| 94 // Remove placeholder information | |
| 95 void find_and_remove(int index, unsigned int hash, | |
| 96 symbolHandle name, Handle loader, Thread* thread); | |
| 97 | |
| 98 // GC support. | |
| 99 void oops_do(OopClosure* f); | |
| 100 | |
| 101 // JVMTI support | |
| 102 void entries_do(void f(symbolOop, oop)); | |
| 103 | |
| 104 #ifndef PRODUCT | |
| 105 void print(); | |
| 106 #endif | |
| 107 void verify(); | |
| 108 }; | |
| 109 | |
| 110 // SeenThread objects represent list of threads that are | |
| 111 // currently performing a load action on a class. | |
| 112 // For class circularity, set before loading a superclass. | |
| 113 // For bootclasssearchpath, set before calling load_instance_class. | |
| 114 // Defining must be single threaded on a class/classloader basis | |
| 115 // For DEFINE_CLASS, the head of the queue owns the | |
| 116 // define token and the rest of the threads wait to return the | |
| 117 // result the first thread gets. | |
| 118 class SeenThread: public CHeapObj { | |
| 119 private: | |
| 120 Thread *_thread; | |
| 121 SeenThread* _stnext; | |
| 122 SeenThread* _stprev; | |
| 123 public: | |
| 124 SeenThread(Thread *thread) { | |
| 125 _thread = thread; | |
| 126 _stnext = NULL; | |
| 127 _stprev = NULL; | |
| 128 } | |
| 129 Thread* thread() const { return _thread;} | |
| 130 void set_thread(Thread *thread) { _thread = thread; } | |
| 131 | |
| 132 SeenThread* next() const { return _stnext;} | |
| 133 void set_next(SeenThread *seen) { _stnext = seen; } | |
| 134 void set_prev(SeenThread *seen) { _stprev = seen; } | |
| 135 | |
| 136 #ifndef PRODUCT | |
| 137 void printActionQ() { | |
| 138 SeenThread* seen = this; | |
| 139 while (seen != NULL) { | |
| 140 seen->thread()->print_value(); | |
| 141 tty->print(", "); | |
| 142 seen = seen->next(); | |
| 143 } | |
| 144 } | |
| 145 #endif // PRODUCT | |
| 146 }; | |
| 147 | |
| 148 // Placeholder objects represent classes currently being loaded. | |
| 149 // All threads examining the placeholder table must hold the | |
| 150 // SystemDictionary_lock, so we don't need special precautions | |
| 151 // on store ordering here. | |
| 152 // The system dictionary is the only user of this class. | |
| 153 | |
| 154 class PlaceholderEntry : public HashtableEntry { | |
| 155 friend class VMStructs; | |
| 156 | |
| 157 | |
| 158 private: | |
| 159 oop _loader; // initiating loader | |
| 160 bool _havesupername; // distinguish between null supername, and unknown | |
| 161 symbolOop _supername; | |
| 162 Thread* _definer; // owner of define token | |
| 163 klassOop _instanceKlass; // instanceKlass from successful define | |
| 164 SeenThread* _superThreadQ; // doubly-linked queue of Threads loading a superclass for this class | |
| 165 SeenThread* _loadInstanceThreadQ; // loadInstance thread | |
| 166 // can be multiple threads if classloader object lock broken by application | |
| 167 // or if classloader supports parallel classloading | |
| 168 | |
| 169 SeenThread* _defineThreadQ; // queue of Threads trying to define this class | |
| 170 // including _definer | |
| 171 // _definer owns token | |
| 172 // queue waits for and returns results from _definer | |
| 173 | |
| 174 public: | |
| 175 // Simple accessors, used only by SystemDictionary | |
| 176 symbolOop klass() const { return (symbolOop)literal(); } | |
| 177 symbolOop* klass_addr() { return (symbolOop*)literal_addr(); } | |
| 178 | |
| 179 oop loader() const { return _loader; } | |
| 180 void set_loader(oop loader) { _loader = loader; } | |
| 181 oop* loader_addr() { return &_loader; } | |
| 182 | |
| 183 bool havesupername() const { return _havesupername; } | |
| 184 void set_havesupername(bool havesupername) { _havesupername = havesupername; } | |
| 185 | |
| 186 symbolOop supername() const { return _supername; } | |
| 187 void set_supername(symbolOop supername) { _supername = supername; } | |
| 188 symbolOop* supername_addr() { return &_supername; } | |
| 189 | |
| 190 Thread* definer() const {return _definer; } | |
| 191 void set_definer(Thread* definer) { _definer = definer; } | |
| 192 | |
| 193 klassOop instanceKlass() const {return _instanceKlass; } | |
| 194 void set_instanceKlass(klassOop instanceKlass) { _instanceKlass = instanceKlass; } | |
| 195 klassOop* instanceKlass_addr() { return &_instanceKlass; } | |
| 196 | |
| 197 SeenThread* superThreadQ() const { return _superThreadQ; } | |
| 198 void set_superThreadQ(SeenThread* SeenThread) { _superThreadQ = SeenThread; } | |
| 199 | |
| 200 SeenThread* loadInstanceThreadQ() const { return _loadInstanceThreadQ; } | |
| 201 void set_loadInstanceThreadQ(SeenThread* SeenThread) { _loadInstanceThreadQ = SeenThread; } | |
| 202 | |
| 203 SeenThread* defineThreadQ() const { return _defineThreadQ; } | |
| 204 void set_defineThreadQ(SeenThread* SeenThread) { _defineThreadQ = SeenThread; } | |
| 205 | |
| 206 PlaceholderEntry* next() const { | |
| 207 return (PlaceholderEntry*)HashtableEntry::next(); | |
| 208 } | |
| 209 | |
| 210 PlaceholderEntry** next_addr() { | |
| 211 return (PlaceholderEntry**)HashtableEntry::next_addr(); | |
| 212 } | |
| 213 | |
| 214 // Test for equality | |
| 215 // Entries are unique for class/classloader name pair | |
| 216 bool equals(symbolOop class_name, oop class_loader) const { | |
| 217 return (klass() == class_name && loader() == class_loader); | |
| 218 } | |
| 219 | |
| 220 SeenThread* actionToQueue(PlaceholderTable::classloadAction action) { | |
| 221 SeenThread* queuehead; | |
| 222 switch (action) { | |
| 223 case PlaceholderTable::LOAD_INSTANCE: | |
| 224 queuehead = _loadInstanceThreadQ; | |
| 225 break; | |
| 226 case PlaceholderTable::LOAD_SUPER: | |
| 227 queuehead = _superThreadQ; | |
| 228 break; | |
| 229 case PlaceholderTable::DEFINE_CLASS: | |
| 230 queuehead = _defineThreadQ; | |
| 231 break; | |
| 232 default: Unimplemented(); | |
| 233 } | |
| 234 return queuehead; | |
| 235 } | |
| 236 | |
| 237 void set_threadQ(SeenThread* seenthread, PlaceholderTable::classloadAction action) { | |
| 238 switch (action) { | |
| 239 case PlaceholderTable::LOAD_INSTANCE: | |
| 240 _loadInstanceThreadQ = seenthread; | |
| 241 break; | |
| 242 case PlaceholderTable::LOAD_SUPER: | |
| 243 _superThreadQ = seenthread; | |
| 244 break; | |
| 245 case PlaceholderTable::DEFINE_CLASS: | |
| 246 _defineThreadQ = seenthread; | |
| 247 break; | |
| 248 default: Unimplemented(); | |
| 249 } | |
| 250 return; | |
| 251 } | |
| 252 | |
| 253 bool super_load_in_progress() { | |
| 254 return (_superThreadQ != NULL); | |
| 255 } | |
| 256 | |
| 257 bool instance_load_in_progress() { | |
| 258 return (_loadInstanceThreadQ != NULL); | |
| 259 } | |
| 260 | |
| 261 bool define_class_in_progress() { | |
| 262 return (_defineThreadQ != NULL); | |
| 263 } | |
| 264 | |
| 265 // Doubly-linked list of Threads per action for class/classloader pair | |
| 266 // Class circularity support: links in thread before loading superclass | |
| 267 // bootstrapsearchpath support: links in a thread before load_instance_class | |
| 268 // definers: use as queue of define requestors, including owner of | |
| 269 // define token. Appends for debugging of requestor order | |
| 270 void add_seen_thread(Thread* thread, PlaceholderTable::classloadAction action) { | |
| 271 assert_lock_strong(SystemDictionary_lock); | |
| 272 SeenThread* threadEntry = new SeenThread(thread); | |
| 273 SeenThread* seen = actionToQueue(action); | |
| 274 | |
| 275 if (seen == NULL) { | |
| 276 set_threadQ(threadEntry, action); | |
| 277 return; | |
| 278 } | |
| 279 SeenThread* next; | |
| 280 while ((next = seen->next()) != NULL) { | |
| 281 seen = next; | |
| 282 } | |
| 283 seen->set_next(threadEntry); | |
| 284 threadEntry->set_prev(seen); | |
| 285 return; | |
| 286 } | |
| 287 | |
| 288 bool check_seen_thread(Thread* thread, PlaceholderTable::classloadAction action) { | |
| 289 assert_lock_strong(SystemDictionary_lock); | |
| 290 SeenThread* threadQ = actionToQueue(action); | |
| 291 SeenThread* seen = threadQ; | |
| 292 while (seen) { | |
| 293 if (thread == seen->thread()) { | |
| 294 return true; | |
| 295 } | |
| 296 seen = seen->next(); | |
| 297 } | |
| 298 return false; | |
| 299 } | |
| 300 | |
| 301 // returns true if seenthreadQ is now empty | |
| 302 // Note, caller must ensure probe still exists while holding | |
| 303 // SystemDictionary_lock | |
| 304 // ignores if cleanup has already been done | |
| 305 // if found, deletes SeenThread | |
| 306 bool remove_seen_thread(Thread* thread, PlaceholderTable::classloadAction action) { | |
| 307 assert_lock_strong(SystemDictionary_lock); | |
| 308 SeenThread* threadQ = actionToQueue(action); | |
| 309 SeenThread* seen = threadQ; | |
| 310 SeenThread* prev = NULL; | |
| 311 while (seen) { | |
| 312 if (thread == seen->thread()) { | |
| 313 if (prev) { | |
| 314 prev->set_next(seen->next()); | |
| 315 } else { | |
| 316 set_threadQ(seen->next(), action); | |
| 317 } | |
| 318 if (seen->next()) { | |
| 319 seen->next()->set_prev(prev); | |
| 320 } | |
| 321 delete seen; | |
| 322 break; | |
| 323 } | |
| 324 prev = seen; | |
| 325 seen = seen->next(); | |
| 326 } | |
| 327 return (actionToQueue(action) == NULL); | |
| 328 } | |
| 329 | |
| 330 // GC support | |
| 331 // Applies "f->do_oop" to all root oops in the placeholder table. | |
| 332 void oops_do(OopClosure* blk); | |
| 333 | |
| 334 // Print method doesn't append a cr | |
| 335 void print() const PRODUCT_RETURN; | |
| 336 void verify() const; | |
| 337 }; | |
| 1972 | 338 |
| 339 #endif // SHARE_VM_CLASSFILE_PLACEHOLDERS_HPP |