Mercurial > hg > truffle
annotate src/share/vm/classfile/placeholders.cpp @ 2177:3582bf76420e
6990754: Use native memory and reference counting to implement SymbolTable
Summary: move symbols from permgen into C heap and reference count them
Reviewed-by: never, acorn, jmasa, stefank
| author | coleenp |
|---|---|
| date | Thu, 27 Jan 2011 16:11:27 -0800 |
| parents | f95d63e2154a |
| children | 1d1603768966 |
| 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 #include "precompiled.hpp" |
| 26 #include "classfile/placeholders.hpp" | |
| 27 #include "classfile/systemDictionary.hpp" | |
| 28 #include "oops/oop.inline.hpp" | |
| 29 #include "runtime/fieldType.hpp" | |
| 30 #include "utilities/hashtable.inline.hpp" | |
| 0 | 31 |
| 32 // Placeholder methods | |
| 33 | |
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34 PlaceholderEntry* PlaceholderTable::new_entry(int hash, Symbol* name, |
| 0 | 35 oop loader, bool havesupername, |
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36 Symbol* supername) { |
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37 PlaceholderEntry* entry = (PlaceholderEntry*)Hashtable<Symbol*>::new_entry(hash, name); |
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38 // Hashtable with Symbol* literal must increment and decrement refcount. |
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39 name->increment_refcount(); |
| 0 | 40 entry->set_loader(loader); |
| 41 entry->set_havesupername(havesupername); | |
| 42 entry->set_supername(supername); | |
| 43 entry->set_superThreadQ(NULL); | |
| 44 entry->set_loadInstanceThreadQ(NULL); | |
| 45 entry->set_defineThreadQ(NULL); | |
| 46 entry->set_definer(NULL); | |
| 47 entry->set_instanceKlass(NULL); | |
| 48 return entry; | |
| 49 } | |
| 50 | |
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51 void PlaceholderTable::free_entry(PlaceholderEntry* entry) { |
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52 // decrement Symbol refcount here because Hashtable doesn't. |
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53 entry->literal()->decrement_refcount(); |
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54 if (entry->supername() != NULL) entry->supername()->decrement_refcount(); |
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55 Hashtable<Symbol*>::free_entry(entry); |
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56 } |
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57 |
| 0 | 58 |
| 59 // Placeholder objects represent classes currently being loaded. | |
| 60 // All threads examining the placeholder table must hold the | |
| 61 // SystemDictionary_lock, so we don't need special precautions | |
| 62 // on store ordering here. | |
| 63 void PlaceholderTable::add_entry(int index, unsigned int hash, | |
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64 Symbol* class_name, Handle class_loader, |
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65 bool havesupername, Symbol* supername){ |
| 0 | 66 assert_locked_or_safepoint(SystemDictionary_lock); |
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67 assert(class_name != NULL, "adding NULL obj"); |
| 0 | 68 |
| 69 // Both readers and writers are locked so it's safe to just | |
| 70 // create the placeholder and insert it in the list without a membar. | |
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71 PlaceholderEntry* entry = new_entry(hash, class_name, class_loader(), havesupername, supername); |
| 0 | 72 add_entry(index, entry); |
| 73 } | |
| 74 | |
| 75 | |
| 76 // Remove a placeholder object. | |
| 77 void PlaceholderTable::remove_entry(int index, unsigned int hash, | |
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78 Symbol* class_name, |
| 0 | 79 Handle class_loader) { |
| 80 assert_locked_or_safepoint(SystemDictionary_lock); | |
| 81 PlaceholderEntry** p = bucket_addr(index); | |
| 82 while (*p) { | |
| 83 PlaceholderEntry *probe = *p; | |
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84 if (probe->hash() == hash && probe->equals(class_name, class_loader())) { |
| 0 | 85 // Delete entry |
| 86 *p = probe->next(); | |
| 87 free_entry(probe); | |
| 88 return; | |
| 89 } | |
| 90 p = probe->next_addr(); | |
| 91 } | |
| 92 } | |
| 93 | |
| 94 PlaceholderEntry* PlaceholderTable::get_entry(int index, unsigned int hash, | |
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95 Symbol* class_name, |
| 0 | 96 Handle class_loader) { |
| 97 assert_locked_or_safepoint(SystemDictionary_lock); | |
| 98 | |
| 99 oop class_loader_ = class_loader(); | |
| 100 | |
| 101 for (PlaceholderEntry *place_probe = bucket(index); | |
| 102 place_probe != NULL; | |
| 103 place_probe = place_probe->next()) { | |
| 104 if (place_probe->hash() == hash && | |
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105 place_probe->equals(class_name, class_loader_)) { |
| 0 | 106 return place_probe; |
| 107 } | |
| 108 } | |
| 109 return NULL; | |
| 110 } | |
| 111 | |
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112 Symbol* PlaceholderTable::find_entry(int index, unsigned int hash, |
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113 Symbol* class_name, |
| 0 | 114 Handle class_loader) { |
| 115 PlaceholderEntry* probe = get_entry(index, hash, class_name, class_loader); | |
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116 return (probe? probe->klassname(): (Symbol*)NULL); |
| 0 | 117 } |
| 118 | |
| 119 // find_and_add returns probe pointer - old or new | |
| 120 // If no entry exists, add a placeholder entry | |
| 121 // If entry exists, reuse entry | |
| 122 // For both, push SeenThread for classloadAction | |
| 123 // if havesupername: this is used for circularity for instanceklass loading | |
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124 PlaceholderEntry* PlaceholderTable::find_and_add(int index, unsigned int hash, Symbol* name, Handle loader, classloadAction action, Symbol* supername, Thread* thread) { |
| 0 | 125 PlaceholderEntry* probe = get_entry(index, hash, name, loader); |
| 126 if (probe == NULL) { | |
| 127 // Nothing found, add place holder | |
| 128 add_entry(index, hash, name, loader, (action == LOAD_SUPER), supername); | |
| 129 probe = get_entry(index, hash, name, loader); | |
| 130 } else { | |
| 131 if (action == LOAD_SUPER) { | |
| 132 probe->set_havesupername(true); | |
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133 probe->set_supername(supername); |
| 0 | 134 } |
| 135 } | |
| 136 if (probe) probe->add_seen_thread(thread, action); | |
| 137 return probe; | |
| 138 } | |
| 139 | |
| 140 | |
| 141 // placeholder used to track class loading internal states | |
| 142 // placeholder existence now for loading superclass/superinterface | |
| 143 // superthreadQ tracks class circularity, while loading superclass/superinterface | |
| 144 // loadInstanceThreadQ tracks load_instance_class calls | |
| 145 // definer() tracks the single thread that owns define token | |
| 146 // defineThreadQ tracks waiters on defining thread's results | |
| 147 // 1st claimant creates placeholder | |
| 148 // find_and_add adds SeenThread entry for appropriate queue | |
| 149 // All claimants remove SeenThread after completing action | |
| 150 // On removal: if definer and all queues empty, remove entry | |
| 151 // Note: you can be in both placeholders and systemDictionary | |
| 152 // see parse_stream for redefine classes | |
| 153 // Therefore - must always check SD first | |
| 154 // Ignores the case where entry is not found | |
| 155 void PlaceholderTable::find_and_remove(int index, unsigned int hash, | |
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156 Symbol* name, Handle loader, Thread* thread) { |
| 0 | 157 assert_locked_or_safepoint(SystemDictionary_lock); |
| 158 PlaceholderEntry *probe = get_entry(index, hash, name, loader); | |
| 159 if (probe != NULL) { | |
| 160 // No other threads using this entry | |
| 161 if ((probe->superThreadQ() == NULL) && (probe->loadInstanceThreadQ() == NULL) | |
| 162 && (probe->defineThreadQ() == NULL) && (probe->definer() == NULL)) { | |
| 163 remove_entry(index, hash, name, loader); | |
| 164 } | |
| 165 } | |
| 166 } | |
| 167 | |
| 168 PlaceholderTable::PlaceholderTable(int table_size) | |
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169 : TwoOopHashtable<Symbol*>(table_size, sizeof(PlaceholderEntry)) { |
| 0 | 170 } |
| 171 | |
| 172 | |
| 173 void PlaceholderTable::oops_do(OopClosure* f) { | |
| 174 for (int index = 0; index < table_size(); index++) { | |
| 175 for (PlaceholderEntry* probe = bucket(index); | |
| 176 probe != NULL; | |
| 177 probe = probe->next()) { | |
| 178 probe->oops_do(f); | |
| 179 } | |
| 180 } | |
| 181 } | |
| 182 | |
| 183 | |
| 184 void PlaceholderEntry::oops_do(OopClosure* blk) { | |
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185 assert(klassname() != NULL, "should have a non-null klass"); |
| 0 | 186 if (_loader != NULL) { |
| 187 blk->do_oop(loader_addr()); | |
| 188 } | |
| 189 if (_instanceKlass != NULL) { | |
| 190 blk->do_oop((oop*)instanceKlass_addr()); | |
| 191 } | |
| 192 } | |
| 193 | |
| 194 // do all entries in the placeholder table | |
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195 void PlaceholderTable::entries_do(void f(Symbol*, oop)) { |
| 0 | 196 for (int index = 0; index < table_size(); index++) { |
| 197 for (PlaceholderEntry* probe = bucket(index); | |
| 198 probe != NULL; | |
| 199 probe = probe->next()) { | |
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200 f(probe->klassname(), probe->loader()); |
| 0 | 201 } |
| 202 } | |
| 203 } | |
| 204 | |
| 205 | |
| 206 #ifndef PRODUCT | |
| 207 // Note, doesn't append a cr | |
| 208 void PlaceholderEntry::print() const { | |
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209 klassname()->print_value(); |
| 0 | 210 if (loader() != NULL) { |
| 211 tty->print(", loader "); | |
| 212 loader()->print_value(); | |
| 213 } | |
| 214 if (supername() != NULL) { | |
| 215 tty->print(", supername "); | |
| 216 supername()->print_value(); | |
| 217 } | |
| 218 if (definer() != NULL) { | |
| 219 tty->print(", definer "); | |
| 220 definer()->print_value(); | |
| 221 } | |
| 222 if (instanceKlass() != NULL) { | |
| 223 tty->print(", instanceKlass "); | |
| 224 instanceKlass()->print_value(); | |
| 225 } | |
| 226 tty->print("\n"); | |
| 227 tty->print("loadInstanceThreadQ threads:"); | |
| 228 loadInstanceThreadQ()->printActionQ(); | |
| 229 tty->print("\n"); | |
| 230 tty->print("superThreadQ threads:"); | |
| 231 superThreadQ()->printActionQ(); | |
| 232 tty->print("\n"); | |
| 233 tty->print("defineThreadQ threads:"); | |
| 234 defineThreadQ()->printActionQ(); | |
| 235 tty->print("\n"); | |
| 236 } | |
| 237 #endif | |
| 238 | |
| 239 void PlaceholderEntry::verify() const { | |
| 240 guarantee(loader() == NULL || loader()->is_instance(), | |
| 241 "checking type of _loader"); | |
| 242 guarantee(instanceKlass() == NULL | |
| 243 || Klass::cast(instanceKlass())->oop_is_instance(), | |
| 244 "checking type of instanceKlass result"); | |
| 245 } | |
| 246 | |
| 247 void PlaceholderTable::verify() { | |
| 248 int element_count = 0; | |
| 249 for (int pindex = 0; pindex < table_size(); pindex++) { | |
| 250 for (PlaceholderEntry* probe = bucket(pindex); | |
| 251 probe != NULL; | |
| 252 probe = probe->next()) { | |
| 253 probe->verify(); | |
| 254 element_count++; // both klasses and place holders count | |
| 255 } | |
| 256 } | |
| 257 guarantee(number_of_entries() == element_count, | |
| 258 "Verify of system dictionary failed"); | |
| 259 } | |
| 260 | |
| 261 | |
| 262 #ifndef PRODUCT | |
| 263 void PlaceholderTable::print() { | |
| 264 for (int pindex = 0; pindex < table_size(); pindex++) { | |
| 265 for (PlaceholderEntry* probe = bucket(pindex); | |
| 266 probe != NULL; | |
| 267 probe = probe->next()) { | |
| 268 if (Verbose) tty->print("%4d: ", pindex); | |
| 269 tty->print(" place holder "); | |
| 270 | |
| 271 probe->print(); | |
| 272 tty->cr(); | |
| 273 } | |
| 274 } | |
| 275 } | |
| 276 #endif |