1 /* 2 * Copyright (c) 2017, 2018, 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 "classfile/javaClasses.hpp" 27 #include "logging/log.hpp" 28 #include "memory/allocation.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "oops/access.inline.hpp" 31 #include "oops/oop.inline.hpp" 32 #include "oops/method.hpp" 33 #include "oops/symbol.hpp" 34 #include "oops/weakHandle.inline.hpp" 35 #include "prims/resolvedMethodTable.hpp" 36 #include "runtime/handles.inline.hpp" 37 #include "runtime/mutexLocker.hpp" 38 #include "runtime/safepointVerifiers.hpp" 39 #include "utilities/hashtable.inline.hpp" 40 #include "utilities/macros.hpp" 41 42 43 oop ResolvedMethodEntry::object() { 44 return literal().resolve(); 45 } 46 47 oop ResolvedMethodEntry::object_no_keepalive() { 48 // The AS_NO_KEEPALIVE peeks at the oop without keeping it alive. 49 // This is dangerous in general but is okay if the loaded oop does 50 // not leak out past a thread transition where a safepoint can happen. 51 // A subsequent oop_load without AS_NO_KEEPALIVE (the object() accessor) 52 // keeps the oop alive before doing so. 53 return literal().peek(); 54 } 55 56 ResolvedMethodTable::ResolvedMethodTable() 57 : Hashtable<ClassLoaderWeakHandle, mtClass>(_table_size, sizeof(ResolvedMethodEntry)) { } 58 59 oop ResolvedMethodTable::lookup(int index, unsigned int hash, Method* method) { 60 for (ResolvedMethodEntry* p = bucket(index); p != NULL; p = p->next()) { 61 if (p->hash() == hash) { 62 63 // Peek the object to check if it is the right target. 64 oop target = p->object_no_keepalive(); 65 66 // The method is in the table as a target already 67 if (target != NULL && java_lang_invoke_ResolvedMethodName::vmtarget(target) == method) { 68 ResourceMark rm; 69 log_debug(membername, table) ("ResolvedMethod entry found for %s index %d", 70 method->name_and_sig_as_C_string(), index); 71 // The object() accessor makes sure the target object is kept alive before 72 // leaking out. 73 return p->object(); 74 } 75 } 76 } 77 return NULL; 78 } 79 80 unsigned int ResolvedMethodTable::compute_hash(Method* method) { 81 unsigned int name_hash = method->name()->identity_hash(); 82 unsigned int signature_hash = method->signature()->identity_hash(); 83 return name_hash ^ signature_hash; 84 } 85 86 87 oop ResolvedMethodTable::lookup(Method* method) { 88 unsigned int hash = compute_hash(method); 89 int index = hash_to_index(hash); 90 return lookup(index, hash, method); 91 } 92 93 oop ResolvedMethodTable::basic_add(Method* method, Handle rmethod_name) { 94 assert_locked_or_safepoint(ResolvedMethodTable_lock); 95 96 unsigned int hash = compute_hash(method); 97 int index = hash_to_index(hash); 98 99 // One was added while aquiring the lock 100 oop entry = lookup(index, hash, method); 101 if (entry != NULL) { 102 return entry; 103 } 104 105 ClassLoaderWeakHandle w = ClassLoaderWeakHandle::create(rmethod_name); 106 ResolvedMethodEntry* p = (ResolvedMethodEntry*) Hashtable<ClassLoaderWeakHandle, mtClass>::new_entry(hash, w); 107 Hashtable<ClassLoaderWeakHandle, mtClass>::add_entry(index, p); 108 ResourceMark rm; 109 log_debug(membername, table) ("ResolvedMethod entry added for %s index %d", 110 method->name_and_sig_as_C_string(), index); 111 return rmethod_name(); 112 } 113 114 ResolvedMethodTable* ResolvedMethodTable::_the_table = NULL; 115 116 oop ResolvedMethodTable::find_method(Method* method) { 117 oop entry = _the_table->lookup(method); 118 return entry; 119 } 120 121 oop ResolvedMethodTable::add_method(Handle resolved_method_name) { 122 MutexLocker ml(ResolvedMethodTable_lock); 123 DEBUG_ONLY(NoSafepointVerifier nsv); 124 125 // Check if method has been redefined while taking out ResolvedMethodTable_lock, if so 126 // use new method. 127 Method* method = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(resolved_method_name()); 128 assert(method->is_method(), "must be method"); 129 if (method->is_old()) { 130 // Replace method with redefined version 131 InstanceKlass* holder = method->method_holder(); 132 method = holder->method_with_idnum(method->method_idnum()); 133 java_lang_invoke_ResolvedMethodName::set_vmtarget(resolved_method_name(), method); 134 } 135 // Set flag in class to indicate this InstanceKlass has entries in the table 136 // to avoid walking table during redefinition if none of the redefined classes 137 // have any membernames in the table. 138 method->method_holder()->set_has_resolved_methods(); 139 140 return _the_table->basic_add(method, resolved_method_name); 141 } 142 143 // Removing entries 144 int ResolvedMethodTable::_oops_removed = 0; 145 int ResolvedMethodTable::_oops_counted = 0; 146 147 // Serially invoke removed unused oops from the table. 148 // This is done late during GC. 149 void ResolvedMethodTable::unlink() { 150 _oops_removed = 0; 151 _oops_counted = 0; 152 for (int i = 0; i < _the_table->table_size(); ++i) { 153 ResolvedMethodEntry** p = _the_table->bucket_addr(i); 154 ResolvedMethodEntry* entry = _the_table->bucket(i); 155 while (entry != NULL) { 156 _oops_counted++; 157 oop l = entry->object_no_keepalive(); 158 if (l != NULL) { 159 p = entry->next_addr(); 160 } else { 161 // Entry has been removed. 162 _oops_removed++; 163 if (log_is_enabled(Debug, membername, table)) { 164 log_debug(membername, table) ("ResolvedMethod entry removed for index %d", i); 165 } 166 entry->literal().release(); 167 *p = entry->next(); 168 _the_table->free_entry(entry); 169 } 170 // get next entry 171 entry = (ResolvedMethodEntry*)HashtableEntry<ClassLoaderWeakHandle, mtClass>::make_ptr(*p); 172 } 173 } 174 log_debug(membername, table) ("ResolvedMethod entries counted %d removed %d", 175 _oops_counted, _oops_removed); 176 } 177 178 #ifndef PRODUCT 179 void ResolvedMethodTable::print() { 180 for (int i = 0; i < table_size(); ++i) { 181 ResolvedMethodEntry* entry = bucket(i); 182 while (entry != NULL) { 183 tty->print("%d : ", i); 184 oop rmethod_name = entry->object_no_keepalive(); 185 if (rmethod_name != NULL) { 186 rmethod_name->print(); 187 Method* m = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(rmethod_name); 188 m->print(); 189 } 190 entry = entry->next(); 191 } 192 } 193 } 194 #endif // PRODUCT 195 196 #if INCLUDE_JVMTI 197 // It is called at safepoint only for RedefineClasses 198 void ResolvedMethodTable::adjust_method_entries(bool * trace_name_printed) { 199 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint"); 200 // For each entry in RMT, change to new method 201 for (int i = 0; i < _the_table->table_size(); ++i) { 202 for (ResolvedMethodEntry* entry = _the_table->bucket(i); 203 entry != NULL; 204 entry = entry->next()) { 205 206 oop mem_name = entry->object_no_keepalive(); 207 // except ones removed 208 if (mem_name == NULL) { 209 continue; 210 } 211 Method* old_method = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(mem_name); 212 213 if (old_method->is_old()) { 214 215 if (old_method->is_deleted()) { 216 // leave deleted method in ResolvedMethod for now (this is a bug that we don't mark 217 // these on_stack) 218 continue; 219 } 220 221 InstanceKlass* holder = old_method->method_holder(); 222 Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum()); 223 assert(holder == new_method->method_holder(), "call after swapping redefined guts"); 224 assert(new_method != NULL, "method_with_idnum() should not be NULL"); 225 assert(old_method != new_method, "sanity check"); 226 227 java_lang_invoke_ResolvedMethodName::set_vmtarget(mem_name, new_method); 228 229 ResourceMark rm; 230 if (!(*trace_name_printed)) { 231 log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name()); 232 *trace_name_printed = true; 233 } 234 log_debug(redefine, class, update, constantpool) 235 ("ResolvedMethod method update: %s(%s)", 236 new_method->name()->as_C_string(), new_method->signature()->as_C_string()); 237 } 238 } 239 } 240 } 241 #endif // INCLUDE_JVMTI