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