Mon, 06 Aug 2012 15:54:45 -0400
7116786: RFE: Detailed information on VerifyErrors
Summary: Provide additional detail in VerifyError messages
Reviewed-by: sspitsyn, acorn
1 /*
2 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
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"
32 // Placeholder methods
34 PlaceholderEntry* PlaceholderTable::new_entry(int hash, Symbol* name,
35 oop loader, bool havesupername,
36 Symbol* supername) {
37 PlaceholderEntry* entry = (PlaceholderEntry*)Hashtable<Symbol*, mtClass>::new_entry(hash, name);
38 // Hashtable with Symbol* literal must increment and decrement refcount.
39 name->increment_refcount();
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 }
51 void PlaceholderTable::free_entry(PlaceholderEntry* entry) {
52 // decrement Symbol refcount here because Hashtable doesn't.
53 entry->literal()->decrement_refcount();
54 if (entry->supername() != NULL) entry->supername()->decrement_refcount();
55 Hashtable<Symbol*, mtClass>::free_entry(entry);
56 }
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,
64 Symbol* class_name, Handle class_loader,
65 bool havesupername, Symbol* supername){
66 assert_locked_or_safepoint(SystemDictionary_lock);
67 assert(class_name != NULL, "adding NULL obj");
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.
71 PlaceholderEntry* entry = new_entry(hash, class_name, class_loader(), havesupername, supername);
72 add_entry(index, entry);
73 }
76 // Remove a placeholder object.
77 void PlaceholderTable::remove_entry(int index, unsigned int hash,
78 Symbol* class_name,
79 Handle class_loader) {
80 assert_locked_or_safepoint(SystemDictionary_lock);
81 PlaceholderEntry** p = bucket_addr(index);
82 while (*p) {
83 PlaceholderEntry *probe = *p;
84 if (probe->hash() == hash && probe->equals(class_name, class_loader())) {
85 // Delete entry
86 *p = probe->next();
87 free_entry(probe);
88 return;
89 }
90 p = probe->next_addr();
91 }
92 }
94 PlaceholderEntry* PlaceholderTable::get_entry(int index, unsigned int hash,
95 Symbol* class_name,
96 Handle class_loader) {
97 assert_locked_or_safepoint(SystemDictionary_lock);
99 oop class_loader_ = class_loader();
101 for (PlaceholderEntry *place_probe = bucket(index);
102 place_probe != NULL;
103 place_probe = place_probe->next()) {
104 if (place_probe->hash() == hash &&
105 place_probe->equals(class_name, class_loader_)) {
106 return place_probe;
107 }
108 }
109 return NULL;
110 }
112 Symbol* PlaceholderTable::find_entry(int index, unsigned int hash,
113 Symbol* class_name,
114 Handle class_loader) {
115 PlaceholderEntry* probe = get_entry(index, hash, class_name, class_loader);
116 return (probe? probe->klassname(): (Symbol*)NULL);
117 }
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
124 PlaceholderEntry* PlaceholderTable::find_and_add(int index, unsigned int hash, Symbol* name, Handle loader, classloadAction action, Symbol* supername, Thread* thread) {
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);
133 probe->set_supername(supername);
134 }
135 }
136 if (probe) probe->add_seen_thread(thread, action);
137 return probe;
138 }
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,
156 Symbol* name, Handle loader, Thread* thread) {
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 }
168 PlaceholderTable::PlaceholderTable(int table_size)
169 : TwoOopHashtable<Symbol*, mtClass>(table_size, sizeof(PlaceholderEntry)) {
170 }
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 }
184 void PlaceholderEntry::oops_do(OopClosure* blk) {
185 assert(klassname() != NULL, "should have a non-null klass");
186 if (_loader != NULL) {
187 blk->do_oop(loader_addr());
188 }
189 if (_instanceKlass != NULL) {
190 blk->do_oop((oop*)instanceKlass_addr());
191 }
192 }
194 // do all entries in the placeholder table
195 void PlaceholderTable::entries_do(void f(Symbol*, oop)) {
196 for (int index = 0; index < table_size(); index++) {
197 for (PlaceholderEntry* probe = bucket(index);
198 probe != NULL;
199 probe = probe->next()) {
200 f(probe->klassname(), probe->loader());
201 }
202 }
203 }
206 #ifndef PRODUCT
207 // Note, doesn't append a cr
208 void PlaceholderEntry::print() const {
209 klassname()->print_value();
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
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 }
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 }
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 ");
271 probe->print();
272 tty->cr();
273 }
274 }
275 }
276 #endif