1 /* 2 * Copyright (c) 2016, 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 "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(Module_lock->owned_by_self(), "should have the Module_lock"); 41 assert(m != NULL, "No module to lookup in this package's qualified exports list"); 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. Clean up 102 // the qualified list at the next safepoint. 103 set_unqual_exported(); 104 } else { 105 // Add the exported module 106 add_qexport(m); 107 } 108 } 109 110 // Set the package as exported to all unnamed modules unless the package is 111 // already unqualifiedly exported. 112 void PackageEntry::set_is_exported_allUnnamed() { 113 if (module()->is_open()) { 114 // No-op for open modules since all packages are unqualifiedly exported 115 return; 116 } 117 118 MutexLocker m1(Module_lock); 119 if (!is_unqual_exported()) { 120 _export_flags = PKG_EXP_ALLUNNAMED; 121 } 122 } 123 124 // Remove dead module entries within the package's exported list. Note that 125 // if all of the modules on the _qualified_exports get purged the list does not 126 // get deleted. This prevents the package from illegally transitioning from 127 // exported to non-exported. 128 void PackageEntry::purge_qualified_exports() { 129 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); 130 if (_must_walk_exports && 131 _qualified_exports != NULL && 132 !_qualified_exports->is_empty()) { 133 ModuleEntry* pkg_module = module(); 134 135 // This package's _must_walk_exports flag will be reset based 136 // on the remaining live modules on the exports list. 137 _must_walk_exports = false; 138 139 if (log_is_enabled(Trace, modules)) { 140 ResourceMark rm; 141 assert(name() != NULL, "PackageEntry without a valid name"); 142 ModuleEntry* pkg_mod = module(); 143 log_trace(modules)("PackageEntry::purge_qualified_exports(): package %s defined in module %s, exports list being walked", 144 name()->as_C_string(), 145 (pkg_mod == NULL || pkg_mod->name() == NULL) ? UNNAMED_MODULE : pkg_mod->name()->as_C_string()); 146 } 147 148 // Go backwards because this removes entries that are dead. 149 int len = _qualified_exports->length(); 150 for (int idx = len - 1; idx >= 0; idx--) { 151 ModuleEntry* module_idx = _qualified_exports->at(idx); 152 ClassLoaderData* cld_idx = module_idx->loader_data(); 153 if (cld_idx->is_unloading()) { 154 _qualified_exports->delete_at(idx); 155 } else { 156 // Update the need to walk this package's exports based on live modules 157 set_export_walk_required(cld_idx); 158 } 159 } 160 } 161 } 162 163 void PackageEntry::delete_qualified_exports() { 164 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); 165 if (_qualified_exports != NULL) { 166 delete _qualified_exports; 167 } 168 _qualified_exports = NULL; 169 } 170 171 PackageEntryTable::PackageEntryTable(int table_size) 172 : Hashtable<Symbol*, mtModule>(table_size, sizeof(PackageEntry)) 173 { 174 } 175 176 PackageEntryTable::~PackageEntryTable() { 177 assert_locked_or_safepoint(Module_lock); 178 179 // Walk through all buckets and all entries in each bucket, 180 // freeing each entry. 181 for (int i = 0; i < table_size(); ++i) { 182 for (PackageEntry* p = bucket(i); p != NULL;) { 183 PackageEntry* to_remove = p; 184 // read next before freeing. 185 p = p->next(); 186 187 // Clean out the C heap allocated qualified exports list first before freeing the entry 188 to_remove->delete_qualified_exports(); 189 to_remove->name()->decrement_refcount(); 190 191 // Unlink from the Hashtable prior to freeing 192 unlink_entry(to_remove); 193 FREE_C_HEAP_ARRAY(char, to_remove); 194 } 195 } 196 assert(number_of_entries() == 0, "should have removed all entries"); 197 assert(new_entry_free_list() == NULL, "entry present on PackageEntryTable's free list"); 198 free_buckets(); 199 } 200 201 PackageEntry* PackageEntryTable::new_entry(unsigned int hash, Symbol* name, ModuleEntry* module) { 202 assert(Module_lock->owned_by_self(), "should have the Module_lock"); 203 PackageEntry* entry = (PackageEntry*) NEW_C_HEAP_ARRAY(char, entry_size(), mtModule); 204 205 // Initialize everything BasicHashtable would 206 entry->set_next(NULL); 207 entry->set_hash(hash); 208 entry->set_literal(name); 209 210 TRACE_INIT_ID(entry); 211 212 // Initialize fields specific to a PackageEntry 213 entry->init(); 214 entry->name()->increment_refcount(); 215 entry->set_module(module); 216 return entry; 217 } 218 219 void PackageEntryTable::add_entry(int index, PackageEntry* new_entry) { 220 assert(Module_lock->owned_by_self(), "should have the Module_lock"); 221 Hashtable<Symbol*, mtModule>::add_entry(index, (HashtableEntry<Symbol*, mtModule>*)new_entry); 222 } 223 224 // Create package in loader's package entry table and return the entry. 225 // If entry already exists, return null. Assume Module lock was taken by caller. 226 PackageEntry* PackageEntryTable::locked_create_entry_or_null(Symbol* name, ModuleEntry* module) { 227 assert(Module_lock->owned_by_self(), "should have the Module_lock"); 228 // Check if package already exists. Return NULL if it does. 229 if (lookup_only(name) != NULL) { 230 return NULL; 231 } else { 232 PackageEntry* entry = new_entry(compute_hash(name), name, module); 233 add_entry(index_for(name), entry); 234 return entry; 235 } 236 } 237 238 PackageEntry* PackageEntryTable::lookup(Symbol* name, ModuleEntry* module) { 239 PackageEntry* p = lookup_only(name); 240 if (p != NULL) { 241 return p; 242 } else { 243 // If not found, add to table. Grab the PackageEntryTable lock first. 244 MutexLocker ml(Module_lock); 245 246 // Since look-up was done lock-free, we need to check if another thread beat 247 // us in the race to insert the package. 248 PackageEntry* test = lookup_only(name); 249 if (test != NULL) { 250 // A race occurred and another thread introduced the package. 251 return test; 252 } else { 253 assert(module != NULL, "module should never be null"); 254 PackageEntry* entry = new_entry(compute_hash(name), name, module); 255 add_entry(index_for(name), entry); 256 return entry; 257 } 258 } 259 } 260 261 PackageEntry* PackageEntryTable::lookup_only(Symbol* name) { 262 int index = index_for(name); 263 for (PackageEntry* p = bucket(index); p != NULL; p = p->next()) { 264 if (p->name()->fast_compare(name) == 0) { 265 return p; 266 } 267 } 268 return NULL; 269 } 270 271 // Called when a define module for java.base is being processed. 272 // Verify the packages loaded thus far are in java.base's package list. 273 void PackageEntryTable::verify_javabase_packages(GrowableArray<Symbol*> *pkg_list) { 274 for (int i = 0; i < table_size(); i++) { 275 for (PackageEntry* entry = bucket(i); 276 entry != NULL; 277 entry = entry->next()) { 278 ModuleEntry* m = entry->module(); 279 Symbol* module_name = (m == NULL ? NULL : m->name()); 280 if (module_name != NULL && 281 (module_name->fast_compare(vmSymbols::java_base()) == 0) && 282 !pkg_list->contains(entry->name())) { 283 ResourceMark rm; 284 vm_exit_during_initialization("A non-" JAVA_BASE_NAME " package was loaded prior to module system initialization", entry->name()->as_C_string()); 285 } 286 } 287 } 288 289 } 290 291 // iteration of qualified exports 292 void PackageEntry::package_exports_do(ModuleClosure* const f) { 293 assert_locked_or_safepoint(Module_lock); 294 assert(f != NULL, "invariant"); 295 296 if (has_qual_exports_list()) { 297 int qe_len = _qualified_exports->length(); 298 299 for (int i = 0; i < qe_len; ++i) { 300 f->do_module(_qualified_exports->at(i)); 301 } 302 } 303 } 304 305 bool PackageEntry::exported_pending_delete() const { 306 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); 307 return (is_unqual_exported() && _qualified_exports != NULL); 308 } 309 310 // Remove dead entries from all packages' exported list 311 void PackageEntryTable::purge_all_package_exports() { 312 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); 313 for (int i = 0; i < table_size(); i++) { 314 for (PackageEntry* entry = bucket(i); 315 entry != NULL; 316 entry = entry->next()) { 317 if (entry->exported_pending_delete()) { 318 // exported list is pending deletion due to a transition 319 // from qualified to unqualified 320 entry->delete_qualified_exports(); 321 } else if (entry->is_qual_exported()) { 322 entry->purge_qualified_exports(); 323 } 324 } 325 } 326 } 327 328 void PackageEntryTable::print(outputStream* st) { 329 st->print_cr("Package Entry Table (table_size=%d, entries=%d)", 330 table_size(), number_of_entries()); 331 for (int i = 0; i < table_size(); i++) { 332 for (PackageEntry* probe = bucket(i); 333 probe != NULL; 334 probe = probe->next()) { 335 probe->print(st); 336 } 337 } 338 } 339 340 // This function may be called from debuggers so access private fields directly 341 // to prevent triggering locking-related asserts that could result from calling 342 // getter methods. 343 void PackageEntry::print(outputStream* st) { 344 ResourceMark rm; 345 st->print_cr("package entry " PTR_FORMAT " name %s module %s classpath_index " 346 INT32_FORMAT " is_exported_unqualified %d is_exported_allUnnamed %d " "next " PTR_FORMAT, 347 p2i(this), name()->as_C_string(), 348 (module()->is_named() ? module()->name()->as_C_string() : UNNAMED_MODULE), 349 _classpath_index, _export_flags == PKG_EXP_UNQUALIFIED, 350 _export_flags == PKG_EXP_ALLUNNAMED, p2i(next())); 351 } 352 353 void PackageEntryTable::verify() { 354 int element_count = 0; 355 for (int index = 0; index < table_size(); index++) { 356 for (PackageEntry* probe = bucket(index); 357 probe != NULL; 358 probe = probe->next()) { 359 probe->verify(); 360 element_count++; 361 } 362 } 363 guarantee(number_of_entries() == element_count, 364 "Verify of Package Entry Table failed"); 365 DEBUG_ONLY(verify_lookup_length((double)number_of_entries() / table_size(), "Package Entry Table")); 366 } 367 368 void PackageEntry::verify() { 369 guarantee(name() != NULL, "A package entry must have a corresponding symbol name."); 370 }