Mercurial > hg > truffle
annotate src/share/vm/classfile/placeholders.cpp @ 5274:e72dd6533eb9
documented importance of nmethod::_graal_compiled_method wrt code unloading and GC
author | Doug Simon <doug.simon@oracle.com> |
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date | Mon, 23 Apr 2012 15:42:30 +0200 |
parents | 1d1603768966 |
children | d2a62e0f25eb |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 2003, 2011, 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 |