1 /* 2 * Copyright (c) 2016, 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/moduleEntry.hpp" 27 #include "classfile/packageEntry.hpp" 28 #include "logging/log.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "oops/symbol.hpp" 31 #include "runtime/handles.inline.hpp" 32 #include "trace/traceMacros.hpp" 33 #include "utilities/events.hpp" 34 #include "utilities/growableArray.hpp" 35 #include "utilities/hashtable.inline.hpp" 36 #include "utilities/ostream.hpp" 37 38 // Returns true if this package specifies m as a qualified export, including through an unnamed export 39 bool PackageEntry::is_qexported_to(ModuleEntry* m) const { 40 assert(m != NULL, "No module to lookup in this package's qualified exports list"); 41 MutexLocker m1(Module_lock); 42 if (is_exported_allUnnamed() && !m->is_named()) { 43 return true; 44 } else if (!has_qual_exports_list()) { 45 return false; 46 } else { 47 return _qualified_exports->contains(m); 48 } 49 } 50 51 // Add a module to the package's qualified export list. 52 void PackageEntry::add_qexport(ModuleEntry* m) { 53 assert(Module_lock->owned_by_self(), "should have the Module_lock"); 54 if (!has_qual_exports_list()) { 55 // Lazily create a package's qualified exports list. 56 // Initial size is small, do not anticipate export lists to be large. 57 _qualified_exports = new (ResourceObj::C_HEAP, mtModule) GrowableArray<ModuleEntry*>(QUAL_EXP_SIZE, true); 58 } 59 60 // Determine, based on this newly established export to module m, 61 // if this package's export list should be walked at a GC safepoint. 62 set_export_walk_required(m->loader_data()); 63 64 // Establish exportability to module m 65 _qualified_exports->append_if_missing(m); 66 } 67 68 // If the module's loader, that an export is being established to, is 69 // not the same loader as this module's and is not one of the 3 builtin 70 // class loaders, then this package's export list must be walked at GC 71 // safepoint. Modules have the same life cycle as their defining class 72 // loaders and should be removed if dead. 73 void PackageEntry::set_export_walk_required(ClassLoaderData* m_loader_data) { 74 assert_locked_or_safepoint(Module_lock); 75 ModuleEntry* this_pkg_mod = module(); 76 if (!_must_walk_exports && 77 (this_pkg_mod == NULL || this_pkg_mod->loader_data() != m_loader_data) && 78 !m_loader_data->is_builtin_class_loader_data()) { 79 _must_walk_exports = true; 80 if (log_is_enabled(Trace, modules)) { 81 ResourceMark rm; 82 assert(name() != NULL, "PackageEntry without a valid name"); 83 log_trace(modules)("PackageEntry::set_export_walk_required(): package %s defined in module %s, exports list must be walked", 84 name()->as_C_string(), 85 (this_pkg_mod == NULL || this_pkg_mod->name() == NULL) ? 86 UNNAMED_MODULE : this_pkg_mod->name()->as_C_string()); 87 } 88 } 89 } 90 91 // Set the package's exported states based on the value of the ModuleEntry. 92 void PackageEntry::set_exported(ModuleEntry* m) { 93 MutexLocker m1(Module_lock); 94 if (is_unqual_exported()) { 95 // An exception could be thrown, but choose to simply ignore. 96 // Illegal to convert an unqualified exported package to be qualifiedly exported 97 return; 98 } 99 100 if (m == NULL) { 101 // NULL indicates the package is being unqualifiedly exported 102 if (has_qual_exports_list()) { 103 // Legit to transition a package from being qualifiedly exported 104 // to unqualified. Clean up the qualified lists at the next 105 // safepoint. 106 _exported_pending_delete = _qualified_exports; 107 } 108 109 // Mark package as unqualifiedly exported 110 set_unqual_exported(); 111 112 } else { 113 // Add the exported module 114 add_qexport(m); 115 } 116 } 117 118 void PackageEntry::set_is_exported_allUnnamed() { 119 MutexLocker m1(Module_lock); 120 if (!is_unqual_exported()) { 121 _is_exported_allUnnamed = true; 122 } 123 } 124 125 // Remove dead module entries within the package's exported list. 126 void PackageEntry::purge_qualified_exports() { 127 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); 128 if (_must_walk_exports && 129 _qualified_exports != NULL && 130 !_qualified_exports->is_empty()) { 131 ModuleEntry* pkg_module = module(); 132 133 // This package's _must_walk_exports flag will be reset based 134 // on the remaining live modules on the exports list. 135 _must_walk_exports = false; 136 137 if (log_is_enabled(Trace, modules)) { 138 ResourceMark rm; 139 assert(name() != NULL, "PackageEntry without a valid name"); 140 ModuleEntry* pkg_mod = module(); 141 log_trace(modules)("PackageEntry::purge_qualified_exports(): package %s defined in module %s, exports list being walked", 142 name()->as_C_string(), 143 (pkg_mod == NULL || pkg_mod->name() == NULL) ? UNNAMED_MODULE : pkg_mod->name()->as_C_string()); 144 } 145 146 // Go backwards because this removes entries that are dead. 147 int len = _qualified_exports->length(); 148 for (int idx = len - 1; idx >= 0; idx--) { 149 ModuleEntry* module_idx = _qualified_exports->at(idx); 150 ClassLoaderData* cld_idx = module_idx->loader_data(); 151 if (cld_idx->is_unloading()) { 152 _qualified_exports->delete_at(idx); 153 } else { 154 // Update the need to walk this package's exports based on live modules 155 set_export_walk_required(cld_idx); 156 } 157 } 158 } 159 } 160 161 void PackageEntry::delete_qualified_exports() { 162 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); 163 if (_exported_pending_delete != NULL) { 164 // If a transition occurred from qualified to unqualified, the _qualified_exports 165 // field should have been NULL'ed out. 166 assert(_qualified_exports == NULL, "Package's exported pending delete, exported list should not be active"); 167 delete _exported_pending_delete; 168 } 169 170 if (_qualified_exports != NULL) { 171 delete _qualified_exports; 172 } 173 174 _exported_pending_delete = NULL; 175 _qualified_exports = NULL; 176 } 177 178 PackageEntryTable::PackageEntryTable(int table_size) 179 : Hashtable<Symbol*, mtModule>(table_size, sizeof(PackageEntry)) 180 { 181 } 182 183 PackageEntryTable::~PackageEntryTable() { 184 assert_locked_or_safepoint(Module_lock); 185 186 // Walk through all buckets and all entries in each bucket, 187 // freeing each entry. 188 for (int i = 0; i < table_size(); ++i) { 189 for (PackageEntry* p = bucket(i); p != NULL;) { 190 PackageEntry* to_remove = p; 191 // read next before freeing. 192 p = p->next(); 193 194 // Clean out the C heap allocated qualified exports list first before freeing the entry 195 to_remove->delete_qualified_exports(); 196 to_remove->name()->decrement_refcount(); 197 198 // Unlink from the Hashtable prior to freeing 199 unlink_entry(to_remove); 200 FREE_C_HEAP_ARRAY(char, to_remove); 201 } 202 } 203 assert(number_of_entries() == 0, "should have removed all entries"); 204 assert(new_entry_free_list() == NULL, "entry present on PackageEntryTable's free list"); 205 free_buckets(); 206 } 207 208 PackageEntry* PackageEntryTable::new_entry(unsigned int hash, Symbol* name, ModuleEntry* module) { 209 assert(Module_lock->owned_by_self(), "should have the Module_lock"); 210 PackageEntry* entry = (PackageEntry*) NEW_C_HEAP_ARRAY(char, entry_size(), mtModule); 211 212 // Initialize everything BasicHashtable would 213 entry->set_next(NULL); 214 entry->set_hash(hash); 215 entry->set_literal(name); 216 217 TRACE_INIT_ID(entry); 218 219 // Initialize fields specific to a PackageEntry 220 entry->init(); 221 entry->name()->increment_refcount(); 222 if (!module->is_named()) { 223 // Set the exported state to true because all packages 224 // within the unnamed module are unqualifiedly exported 225 entry->set_unqual_exported(); 226 } 227 entry->set_module(module); 228 return entry; 229 } 230 231 void PackageEntryTable::add_entry(int index, PackageEntry* new_entry) { 232 assert(Module_lock->owned_by_self(), "should have the Module_lock"); 233 Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry); 234 } 235 236 // Create package in loader's package entry table and return the entry. 237 // If entry already exists, return null. Assume Module lock was taken by caller. 238 PackageEntry* PackageEntryTable::locked_create_entry_or_null(Symbol* name, ModuleEntry* module) { 239 assert(Module_lock->owned_by_self(), "should have the Module_lock"); 240 // Check if package already exists. Return NULL if it does. 241 if (lookup_only(name) != NULL) { 242 return NULL; 243 } else { 244 PackageEntry* entry = new_entry(compute_hash(name), name, module); 245 add_entry(index_for(name), entry); 246 return entry; 247 } 248 } 249 250 PackageEntry* PackageEntryTable::lookup(Symbol* name, ModuleEntry* module) { 251 PackageEntry* p = lookup_only(name); 252 if (p != NULL) { 253 return p; 254 } else { 255 // If not found, add to table. Grab the PackageEntryTable lock first. 256 MutexLocker ml(Module_lock); 257 258 // Since look-up was done lock-free, we need to check if another thread beat 259 // us in the race to insert the package. 260 PackageEntry* test = lookup_only(name); 261 if (test != NULL) { 262 // A race occurred and another thread introduced the package. 263 return test; 264 } else { 265 assert(module != NULL, "module should never be null"); 266 PackageEntry* entry = new_entry(compute_hash(name), name, module); 267 add_entry(index_for(name), entry); 268 return entry; 269 } 270 } 271 } 272 273 PackageEntry* PackageEntryTable::lookup_only(Symbol* name) { 274 int index = index_for(name); 275 for (PackageEntry* p = bucket(index); p != NULL; p = p->next()) { 276 if (p->name()->fast_compare(name) == 0) { 277 return p; 278 } 279 } 280 return NULL; 281 } 282 283 // Called when a define module for java.base is being processed. 284 // Verify the packages loaded thus far are in java.base's package list. 285 void PackageEntryTable::verify_javabase_packages(GrowableArray<Symbol*> *pkg_list) { 286 for (int i = 0; i < table_size(); i++) { 287 for (PackageEntry* entry = bucket(i); 288 entry != NULL; 289 entry = entry->next()) { 290 ModuleEntry* m = entry->module(); 291 Symbol* module_name = (m == NULL ? NULL : m->name()); 292 if (module_name != NULL && 293 (module_name->fast_compare(vmSymbols::java_base()) == 0) && 294 !pkg_list->contains(entry->name())) { 295 ResourceMark rm; 296 vm_exit_during_initialization("A non-java.base package was loaded prior to module system initialization", entry->name()->as_C_string()); 297 } 298 } 299 } 300 301 } 302 303 // iteration of qualified exports 304 void PackageEntry::package_exports_do(ModuleClosure* const f) { 305 assert_locked_or_safepoint(Module_lock); 306 assert(f != NULL, "invariant"); 307 308 if (has_qual_exports_list()) { 309 int qe_len = _qualified_exports->length(); 310 311 for (int i = 0; i < qe_len; ++i) { 312 f->do_module(_qualified_exports->at(i)); 313 } 314 } 315 } 316 317 // Remove dead entries from all packages' exported list 318 void PackageEntryTable::purge_all_package_exports() { 319 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); 320 for (int i = 0; i < table_size(); i++) { 321 for (PackageEntry* entry = bucket(i); 322 entry != NULL; 323 entry = entry->next()) { 324 if (entry->exported_pending_delete()) { 325 // exported list is pending deletion due to a transition 326 // from qualified to unqualified 327 entry->delete_qualified_exports(); 328 } else if (entry->is_qual_exported()) { 329 entry->purge_qualified_exports(); 330 } 331 } 332 } 333 } 334 335 void PackageEntryTable::print(outputStream* st) { 336 st->print_cr("Package Entry Table (table_size=%d, entries=%d)", 337 table_size(), number_of_entries()); 338 for (int i = 0; i < table_size(); i++) { 339 for (PackageEntry* probe = bucket(i); 340 probe != NULL; 341 probe = probe->next()) { 342 probe->print(st); 343 } 344 } 345 } 346 347 void PackageEntry::print(outputStream* st) { 348 ResourceMark rm; 349 st->print_cr("package entry " PTR_FORMAT " name %s module %s classpath_index " 350 INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next " PTR_FORMAT, 351 p2i(this), name()->as_C_string(), 352 (module()->is_named() ? module()->name()->as_C_string() : UNNAMED_MODULE), 353 _classpath_index, _is_exported_unqualified, _is_exported_allUnnamed, p2i(next())); 354 } 355 356 void PackageEntryTable::verify() { 357 int element_count = 0; 358 for (int index = 0; index < table_size(); index++) { 359 for (PackageEntry* probe = bucket(index); 360 probe != NULL; 361 probe = probe->next()) { 362 probe->verify(); 363 element_count++; 364 } 365 } 366 guarantee(number_of_entries() == element_count, 367 "Verify of Package Entry Table failed"); 368 DEBUG_ONLY(verify_lookup_length((double)number_of_entries() / table_size(), "Package Entry Table")); 369 } 370 371 void PackageEntry::verify() { 372 guarantee(name() != NULL, "A package entry must have a corresponding symbol name."); 373 }