1 /*
2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
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 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/shared/gcLocker.hpp"
27 #include "memory/allocation.hpp"
28 #include "oops/oop.inline.hpp"
29 #include "oops/method.hpp"
30 #include "oops/symbol.hpp"
31 #include "prims/resolvedMethodTable.hpp"
32 #include "runtime/handles.inline.hpp"
33 #include "runtime/mutexLocker.hpp"
34 #include "utilities/hashtable.inline.hpp"
35 #include "utilities/macros.hpp"
36 #if INCLUDE_ALL_GCS
37 #include "gc/g1/g1SATBCardTableModRefBS.hpp"
38 #endif
39
40
41 ResolvedMethodTable::ResolvedMethodTable()
42 : Hashtable<oop, mtClass>(_table_size, sizeof(ResolvedMethodEntry)) { }
43
44 oop ResolvedMethodTable::lookup(int index, unsigned int hash, Method* method) {
45 for (ResolvedMethodEntry* p = bucket(index); p != NULL; p = p->next()) {
46 if (p->hash() == hash) {
47 oop target = p->literal();
48 // The method is in the table as a target already
49 if (java_lang_invoke_ResolvedMethodName::vmtarget(target) == method) {
50 ResourceMark rm;
51 log_debug(membername, table) ("ResolvedMethod entry found for %s index %d",
52 method->name_and_sig_as_C_string(), index);
53 return target;
54 }
55 }
56 }
57 return NULL;
58 }
59
60 unsigned int ResolvedMethodTable::compute_hash(Method* method) {
61 unsigned int name_hash = method->name()->identity_hash();
62 unsigned int signature_hash = method->signature()->identity_hash();
63 return name_hash ^ signature_hash;
64 }
65
66
67 oop ResolvedMethodTable::lookup(Method* method) {
68 unsigned int hash = compute_hash(method);
69 int index = hash_to_index(hash);
70 return lookup(index, hash, method);
71 }
72
73 // Tell the GC that this oop was looked up in the table
74 static void ensure_oop_alive(oop mname) {
75 // A lookup in the ResolvedMethodTable could return an object that was previously
76 // considered dead. The SATB part of G1 needs to get notified about this
77 // potential resurrection, otherwise the marking might not find the object.
78 #if INCLUDE_ALL_GCS
79 if ((UseG1GC || (UseShenandoahGC && ShenandoahSATBBarrier)) && mname != NULL) {
80 G1SATBCardTableModRefBS::enqueue(mname);
81 }
82 #endif
83 }
84
85 oop ResolvedMethodTable::basic_add(Method* method, oop rmethod_name) {
86 assert_locked_or_safepoint(ResolvedMethodTable_lock);
87
88 unsigned int hash = compute_hash(method);
89 int index = hash_to_index(hash);
90
91 // One was added while aquiring the lock
92 oop entry = lookup(index, hash, method);
93 if (entry != NULL) {
94 ensure_oop_alive(entry);
95 return entry;
96 }
97
98 ResolvedMethodEntry* p = (ResolvedMethodEntry*) Hashtable<oop, mtClass>::new_entry(hash, rmethod_name);
99 Hashtable<oop, mtClass>::add_entry(index, p);
100 ResourceMark rm;
101 log_debug(membername, table) ("ResolvedMethod entry added for %s index %d",
102 method->name_and_sig_as_C_string(), index);
103 return p->literal();
104 }
105
106 ResolvedMethodTable* ResolvedMethodTable::_the_table = NULL;
107
108 oop ResolvedMethodTable::find_method(Method* method) {
109 oop entry = _the_table->lookup(method);
110 ensure_oop_alive(entry);
111 return entry;
112 }
113
114 oop ResolvedMethodTable::add_method(Handle resolved_method_name) {
115 MutexLocker ml(ResolvedMethodTable_lock);
116 DEBUG_ONLY(NoSafepointVerifier nsv);
117
118 // Check if method has been redefined while taking out ResolvedMethodTable_lock, if so
119 // use new method.
120 Method* method = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(resolved_method_name());
121 assert(method->is_method(), "must be method");
122 if (method->is_old()) {
123 // Replace method with redefined version
124 InstanceKlass* holder = method->method_holder();
125 method = holder->method_with_idnum(method->method_idnum());
126 java_lang_invoke_ResolvedMethodName::set_vmtarget(resolved_method_name(), method);
127 }
128 // Set flag in class to indicate this InstanceKlass has entries in the table
129 // to avoid walking table during redefinition if none of the redefined classes
130 // have any membernames in the table.
131 method->method_holder()->set_has_resolved_methods();
132
133 return _the_table->basic_add(method, resolved_method_name());
134 }
135
136 // Removing entries
137 int ResolvedMethodTable::_oops_removed = 0;
138 int ResolvedMethodTable::_oops_counted = 0;
139
140 // Serially invoke removed unused oops from the table.
141 // This is done late during GC.
142 void ResolvedMethodTable::unlink(BoolObjectClosure* is_alive) {
143 _oops_removed = 0;
144 _oops_counted = 0;
145 for (int i = 0; i < _the_table->table_size(); ++i) {
146 ResolvedMethodEntry** p = _the_table->bucket_addr(i);
147 ResolvedMethodEntry* entry = _the_table->bucket(i);
148 while (entry != NULL) {
149 _oops_counted++;
150 if (is_alive->do_object_b(entry->literal())) {
151 p = entry->next_addr();
152 } else {
153 _oops_removed++;
154 if (log_is_enabled(Debug, membername, table)) {
155 Method* m = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(entry->literal());
156 ResourceMark rm;
157 log_debug(membername, table) ("ResolvedMethod entry removed for %s index %d",
158 m->name_and_sig_as_C_string(), i);
159 }
160 *p = entry->next();
161 _the_table->free_entry(entry);
162 }
163 // get next entry
164 entry = (ResolvedMethodEntry*)HashtableEntry<oop, mtClass>::make_ptr(*p);
165 }
166 }
167 log_debug(membername, table) ("ResolvedMethod entries counted %d removed %d",
168 _oops_counted, _oops_removed);
169 }
170
171 // Serially invoke "f->do_oop" on the locations of all oops in the table.
172 void ResolvedMethodTable::oops_do(OopClosure* f) {
173 for (int i = 0; i < _the_table->table_size(); ++i) {
174 ResolvedMethodEntry* entry = _the_table->bucket(i);
175 while (entry != NULL) {
176 f->do_oop(entry->literal_addr());
177 entry = entry->next();
178 }
179 }
180 }
181
182 #ifndef PRODUCT
183 void ResolvedMethodTable::print() {
184 for (int i = 0; i < table_size(); ++i) {
185 ResolvedMethodEntry* entry = bucket(i);
186 while (entry != NULL) {
187 tty->print("%d : ", i);
188 oop rmethod_name = entry->literal();
189 rmethod_name->print();
190 Method* m = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(rmethod_name);
191 m->print();
192 entry = entry->next();
193 }
194 }
195 }
196 #endif // PRODUCT
197
198 #if INCLUDE_JVMTI
199 // It is called at safepoint only for RedefineClasses
200 void ResolvedMethodTable::adjust_method_entries(bool * trace_name_printed) {
201 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
202 // For each entry in RMT, change to new method
203 for (int i = 0; i < _the_table->table_size(); ++i) {
204 ResolvedMethodEntry* entry = _the_table->bucket(i);
205 while (entry != NULL) {
206
207 oop mem_name = entry->literal();
208 Method* old_method = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(mem_name);
209
210 if (old_method->is_old()) {
211
212 if (old_method->is_deleted()) {
213 // leave deleted method in ResolvedMethod for now (this is a bug that we don't mark
214 // these on_stack)
215 continue;
216 }
217
218 InstanceKlass* holder = old_method->method_holder();
219 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
220 assert(holder == new_method->method_holder(), "call after swapping redefined guts");
221 assert(new_method != NULL, "method_with_idnum() should not be NULL");
222 assert(old_method != new_method, "sanity check");
223
224 java_lang_invoke_ResolvedMethodName::set_vmtarget(mem_name, new_method);
225
226 ResourceMark rm;
227 if (!(*trace_name_printed)) {
228 log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
229 *trace_name_printed = true;
230 }
231 log_debug(redefine, class, update, constantpool)
232 ("ResolvedMethod method update: %s(%s)",
233 new_method->name()->as_C_string(), new_method->signature()->as_C_string());
234 }
235 entry = entry->next();
236 }
237 }
238 }
239 #endif // INCLUDE_JVMTI