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/access.inline.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "oops/method.hpp"
31 #include "oops/symbol.hpp"
32 #include "prims/resolvedMethodTable.hpp"
33 #include "runtime/handles.inline.hpp"
34 #include "runtime/mutexLocker.hpp"
35 #include "utilities/hashtable.inline.hpp"
36 #include "utilities/macros.hpp"
37
38
39 oop ResolvedMethodEntry::object() {
40 return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(literal_addr());
41 }
42
43 oop ResolvedMethodEntry::object_no_keepalive() {
44 // The AS_NO_KEEPALIVE peeks at the oop without keeping it alive.
45 // This is dangerous in general but is okay if the loaded oop does
46 // not leak out past a thread transition where a safepoint can happen.
47 // A subsequent oop_load without AS_NO_KEEPALIVE (the object() accessor)
48 // keeps the oop alive before doing so.
49 return RootAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(literal_addr());
50 }
51
52 ResolvedMethodTable::ResolvedMethodTable()
53 : Hashtable<oop, mtClass>(_table_size, sizeof(ResolvedMethodEntry)) { }
54
55 oop ResolvedMethodTable::lookup(int index, unsigned int hash, Method* method) {
56 for (ResolvedMethodEntry* p = bucket(index); p != NULL; p = p->next()) {
57 if (p->hash() == hash) {
58
59 // Peek the object to check if it is the right target.
60 oop target = p->object_no_keepalive();
61
62 // The method is in the table as a target already
63 if (java_lang_invoke_ResolvedMethodName::vmtarget(target) == method) {
64 ResourceMark rm;
65 log_debug(membername, table) ("ResolvedMethod entry found for %s index %d",
66 method->name_and_sig_as_C_string(), index);
67 // The object() accessor makes sure the target object is kept alive before
68 // leaking out.
69 return p->object();
70 }
71 }
72 }
73 return NULL;
74 }
75
76 unsigned int ResolvedMethodTable::compute_hash(Method* method) {
77 unsigned int name_hash = method->name()->identity_hash();
78 unsigned int signature_hash = method->signature()->identity_hash();
79 return name_hash ^ signature_hash;
80 }
81
82
83 oop ResolvedMethodTable::lookup(Method* method) {
84 unsigned int hash = compute_hash(method);
85 int index = hash_to_index(hash);
86 return lookup(index, hash, method);
87 }
88
89 oop ResolvedMethodTable::basic_add(Method* method, oop rmethod_name) {
90 assert_locked_or_safepoint(ResolvedMethodTable_lock);
91
92 unsigned int hash = compute_hash(method);
93 int index = hash_to_index(hash);
94
95 // One was added while aquiring the lock
96 oop entry = lookup(index, hash, method);
97 if (entry != NULL) {
98 return entry;
99 }
100
101 ResolvedMethodEntry* p = (ResolvedMethodEntry*) Hashtable<oop, mtClass>::new_entry(hash, rmethod_name);
102 Hashtable<oop, mtClass>::add_entry(index, p);
103 ResourceMark rm;
104 log_debug(membername, table) ("ResolvedMethod entry added for %s index %d",
105 method->name_and_sig_as_C_string(), index);
106 return rmethod_name;
107 }
108
109 ResolvedMethodTable* ResolvedMethodTable::_the_table = NULL;
110
111 oop ResolvedMethodTable::find_method(Method* method) {
112 oop entry = _the_table->lookup(method);
113 return entry;
114 }
115
116 oop ResolvedMethodTable::add_method(Handle resolved_method_name) {
117 MutexLocker ml(ResolvedMethodTable_lock);
118 DEBUG_ONLY(NoSafepointVerifier nsv);
119
120 // Check if method has been redefined while taking out ResolvedMethodTable_lock, if so
121 // use new method.
122 Method* method = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(resolved_method_name());
123 assert(method->is_method(), "must be method");
124 if (method->is_old()) {
125 // Replace method with redefined version
126 InstanceKlass* holder = method->method_holder();
127 method = holder->method_with_idnum(method->method_idnum());
128 java_lang_invoke_ResolvedMethodName::set_vmtarget(resolved_method_name(), method);
129 }
130 // Set flag in class to indicate this InstanceKlass has entries in the table
131 // to avoid walking table during redefinition if none of the redefined classes
132 // have any membernames in the table.
133 method->method_holder()->set_has_resolved_methods();
134
135 return _the_table->basic_add(method, resolved_method_name());
136 }
137
138 // Removing entries
139 int ResolvedMethodTable::_oops_removed = 0;
140 int ResolvedMethodTable::_oops_counted = 0;
141
142 // Serially invoke removed unused oops from the table.
143 // This is done late during GC.
144 void ResolvedMethodTable::unlink(BoolObjectClosure* is_alive) {
145 _oops_removed = 0;
146 _oops_counted = 0;
147 for (int i = 0; i < _the_table->table_size(); ++i) {
148 ResolvedMethodEntry** p = _the_table->bucket_addr(i);
149 ResolvedMethodEntry* entry = _the_table->bucket(i);
150 while (entry != NULL) {
151 _oops_counted++;
152 if (is_alive->do_object_b(entry->object_no_keepalive())) {
153 p = entry->next_addr();
154 } else {
155 _oops_removed++;
156 if (log_is_enabled(Debug, membername, table)) {
157 Method* m = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(entry->object_no_keepalive());
158 ResourceMark rm;
159 log_debug(membername, table) ("ResolvedMethod entry removed for %s index %d",
160 m->name_and_sig_as_C_string(), i);
161 }
162 *p = entry->next();
163 _the_table->free_entry(entry);
164 }
165 // get next entry
166 entry = (ResolvedMethodEntry*)HashtableEntry<oop, mtClass>::make_ptr(*p);
167 }
168 }
169 log_debug(membername, table) ("ResolvedMethod entries counted %d removed %d",
170 _oops_counted, _oops_removed);
171 }
172
173 // Serially invoke "f->do_oop" on the locations of all oops in the table.
174 void ResolvedMethodTable::oops_do(OopClosure* f) {
175 for (int i = 0; i < _the_table->table_size(); ++i) {
176 ResolvedMethodEntry* entry = _the_table->bucket(i);
177 while (entry != NULL) {
178 f->do_oop(entry->literal_addr());
179 entry = entry->next();
180 }
181 }
182 }
183
184 #ifndef PRODUCT
185 void ResolvedMethodTable::print() {
186 for (int i = 0; i < table_size(); ++i) {
187 ResolvedMethodEntry* entry = bucket(i);
188 while (entry != NULL) {
189 tty->print("%d : ", i);
190 oop rmethod_name = entry->object_no_keepalive();
191 rmethod_name->print();
192 Method* m = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(rmethod_name);
193 m->print();
194 entry = entry->next();
195 }
196 }
197 }
198 #endif // PRODUCT
199
200 #if INCLUDE_JVMTI
201 // It is called at safepoint only for RedefineClasses
202 void ResolvedMethodTable::adjust_method_entries(bool * trace_name_printed) {
203 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
204 // For each entry in RMT, change to new method
205 for (int i = 0; i < _the_table->table_size(); ++i) {
206 ResolvedMethodEntry* entry = _the_table->bucket(i);
207 while (entry != NULL) {
208 oop mem_name = entry->object_no_keepalive();
209 Method* old_method = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(mem_name);
210
211 if (old_method->is_old()) {
212
213 if (old_method->is_deleted()) {
214 // leave deleted method in ResolvedMethod for now (this is a bug that we don't mark
215 // these on_stack)
216 continue;
217 }
218
219 InstanceKlass* holder = old_method->method_holder();
220 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
221 assert(holder == new_method->method_holder(), "call after swapping redefined guts");
222 assert(new_method != NULL, "method_with_idnum() should not be NULL");
223 assert(old_method != new_method, "sanity check");
224
225 java_lang_invoke_ResolvedMethodName::set_vmtarget(mem_name, new_method);
226
227 ResourceMark rm;
228 if (!(*trace_name_printed)) {
229 log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
230 *trace_name_printed = true;
231 }
232 log_debug(redefine, class, update, constantpool)
233 ("ResolvedMethod method update: %s(%s)",
234 new_method->name()->as_C_string(), new_method->signature()->as_C_string());
235 }
236 entry = entry->next();
237 }
238 }
239 }
240 #endif // INCLUDE_JVMTI