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