classLoader.hpp revision 1472:c18cbe5936b8
1303231Sdim/* 2303231Sdim * Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved. 3303231Sdim * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4303231Sdim * 5303231Sdim * This code is free software; you can redistribute it and/or modify it 6303231Sdim * under the terms of the GNU General Public License version 2 only, as 7303231Sdim * published by the Free Software Foundation. 8303231Sdim * 9303231Sdim * This code is distributed in the hope that it will be useful, but WITHOUT 10303231Sdim * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11303231Sdim * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12303231Sdim * version 2 for more details (a copy is included in the LICENSE file that 13303231Sdim * accompanied this code). 14303231Sdim * 15303231Sdim * You should have received a copy of the GNU General Public License version 16303231Sdim * 2 along with this work; if not, write to the Free Software Foundation, 17303231Sdim * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18314564Sdim * 19303231Sdim * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20303231Sdim * or visit www.oracle.com if you need additional information or have any 21303231Sdim * questions. 22303231Sdim * 23303231Sdim */ 24303231Sdim 25303231Sdim// The VM class loader. 26303231Sdim#include <sys/stat.h> 27303231Sdim 28303231Sdim 29303231Sdim// Meta-index (optional, to be able to skip opening boot classpath jar files) 30303231Sdimclass MetaIndex: public CHeapObj { 31303231Sdim private: 32303231Sdim char** _meta_package_names; 33303231Sdim int _num_meta_package_names; 34303231Sdim public: 35303231Sdim MetaIndex(char** meta_package_names, int num_meta_package_names); 36303231Sdim ~MetaIndex(); 37303231Sdim bool may_contain(const char* class_name); 38303231Sdim}; 39303231Sdim 40303231Sdim 41303231Sdim// Class path entry (directory or zip file) 42303231Sdim 43303231Sdimclass ClassPathEntry: public CHeapObj { 44303231Sdim private: 45303231Sdim ClassPathEntry* _next; 46321369Sdim public: 47321369Sdim // Next entry in class path 48303231Sdim ClassPathEntry* next() { return _next; } 49303231Sdim void set_next(ClassPathEntry* next) { 50303231Sdim // may have unlocked readers, so write atomically. 51303231Sdim OrderAccess::release_store_ptr(&_next, next); 52303231Sdim } 53303231Sdim virtual bool is_jar_file() = 0; 54303231Sdim virtual const char* name() = 0; 55303231Sdim virtual bool is_lazy(); 56303231Sdim // Constructor 57303231Sdim ClassPathEntry(); 58303231Sdim // Attempt to locate file_name through this class path entry. 59303231Sdim // Returns a class file parsing stream if successfull. 60303231Sdim virtual ClassFileStream* open_stream(const char* name) = 0; 61303231Sdim // Debugging 62303231Sdim NOT_PRODUCT(virtual void compile_the_world(Handle loader, TRAPS) = 0;) 63303231Sdim NOT_PRODUCT(virtual bool is_rt_jar() = 0;) 64303231Sdim}; 65303231Sdim 66303231Sdim 67303231Sdimclass ClassPathDirEntry: public ClassPathEntry { 68303231Sdim private: 69303231Sdim char* _dir; // Name of directory 70303231Sdim public: 71303231Sdim bool is_jar_file() { return false; } 72303231Sdim const char* name() { return _dir; } 73303231Sdim ClassPathDirEntry(char* dir); 74303231Sdim ClassFileStream* open_stream(const char* name); 75303231Sdim // Debugging 76303231Sdim NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);) 77303231Sdim NOT_PRODUCT(bool is_rt_jar();) 78326496Sdim}; 79326496Sdim 80326496Sdim 81326496Sdim// Type definitions for zip file and zip file entry 82326496Sdimtypedef void* jzfile; 83303231Sdimtypedef struct { 84303231Sdim char *name; /* entry name */ 85303231Sdim jlong time; /* modification time */ 86303231Sdim jlong size; /* size of uncompressed data */ 87303231Sdim jlong csize; /* size of compressed data (zero if uncompressed) */ 88303231Sdim jint crc; /* crc of uncompressed data */ 89303231Sdim char *comment; /* optional zip file comment */ 90303231Sdim jbyte *extra; /* optional extra data */ 91303231Sdim jlong pos; /* position of LOC header (if negative) or data */ 92303231Sdim} jzentry; 93303231Sdim 94303231Sdim 95303231Sdimclass ClassPathZipEntry: public ClassPathEntry { 96303231Sdim private: 97303231Sdim jzfile* _zip; // The zip archive 98303231Sdim char* _zip_name; // Name of zip archive 99303231Sdim public: 100303231Sdim bool is_jar_file() { return true; } 101303231Sdim const char* name() { return _zip_name; } 102303231Sdim ClassPathZipEntry(jzfile* zip, const char* zip_name); 103314564Sdim ~ClassPathZipEntry(); 104314564Sdim ClassFileStream* open_stream(const char* name); 105314564Sdim void contents_do(void f(const char* name, void* context), void* context); 106303231Sdim // Debugging 107303231Sdim NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);) 108303231Sdim NOT_PRODUCT(void compile_the_world12(Handle loader, TRAPS);) // JDK 1.2 version 109303231Sdim NOT_PRODUCT(void compile_the_world13(Handle loader, TRAPS);) // JDK 1.3 version 110303231Sdim NOT_PRODUCT(bool is_rt_jar();) 111303231Sdim NOT_PRODUCT(bool is_rt_jar12();) 112303231Sdim NOT_PRODUCT(bool is_rt_jar13();) 113303231Sdim}; 114303231Sdim 115303231Sdim 116303231Sdim// For lazier loading of boot class path entries 117303231Sdimclass LazyClassPathEntry: public ClassPathEntry { 118303231Sdim private: 119303231Sdim char* _path; // dir or file 120303231Sdim struct stat _st; 121303231Sdim MetaIndex* _meta_index; 122303231Sdim volatile ClassPathEntry* _resolved_entry; 123303231Sdim ClassPathEntry* resolve_entry(); 124303231Sdim public: 125303231Sdim bool is_jar_file(); 126314564Sdim const char* name() { return _path; } 127314564Sdim LazyClassPathEntry(char* path, struct stat st); 128314564Sdim ClassFileStream* open_stream(const char* name); 129303231Sdim void set_meta_index(MetaIndex* meta_index) { _meta_index = meta_index; } 130303231Sdim virtual bool is_lazy(); 131303231Sdim // Debugging 132303231Sdim NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);) 133303231Sdim NOT_PRODUCT(bool is_rt_jar();) 134303231Sdim}; 135303231Sdim 136303231Sdimclass PackageHashtable; 137303231Sdimclass PackageInfo; 138303231Sdimclass HashtableBucket; 139303231Sdim 140303231Sdimclass ClassLoader: AllStatic { 141303231Sdim public: 142314564Sdim enum SomeConstants { 143314564Sdim package_hash_table_size = 31 // Number of buckets 144314564Sdim }; 145314564Sdim private: 146314564Sdim friend class LazyClassPathEntry; 147314564Sdim 148314564Sdim // Performance counters 149303231Sdim static PerfCounter* _perf_accumulated_time; 150303231Sdim static PerfCounter* _perf_classes_inited; 151303231Sdim static PerfCounter* _perf_class_init_time; 152303231Sdim static PerfCounter* _perf_class_init_selftime; 153303231Sdim static PerfCounter* _perf_classes_verified; 154303231Sdim static PerfCounter* _perf_class_verify_time; 155303231Sdim static PerfCounter* _perf_class_verify_selftime; 156303231Sdim static PerfCounter* _perf_classes_linked; 157303231Sdim static PerfCounter* _perf_class_link_time; 158303231Sdim static PerfCounter* _perf_class_link_selftime; 159303231Sdim static PerfCounter* _perf_class_parse_time; 160303231Sdim static PerfCounter* _perf_class_parse_selftime; 161303231Sdim static PerfCounter* _perf_sys_class_lookup_time; 162303231Sdim static PerfCounter* _perf_shared_classload_time; 163303231Sdim static PerfCounter* _perf_sys_classload_time; 164303231Sdim static PerfCounter* _perf_app_classload_time; 165303231Sdim static PerfCounter* _perf_app_classload_selftime; 166303231Sdim static PerfCounter* _perf_app_classload_count; 167314564Sdim static PerfCounter* _perf_define_appclasses; 168314564Sdim static PerfCounter* _perf_define_appclass_time; 169303231Sdim static PerfCounter* _perf_define_appclass_selftime; 170303231Sdim static PerfCounter* _perf_app_classfile_bytes_read; 171303231Sdim static PerfCounter* _perf_sys_classfile_bytes_read; 172303231Sdim 173303231Sdim static PerfCounter* _sync_systemLoaderLockContentionRate; 174 static PerfCounter* _sync_nonSystemLoaderLockContentionRate; 175 static PerfCounter* _sync_JVMFindLoadedClassLockFreeCounter; 176 static PerfCounter* _sync_JVMDefineClassLockFreeCounter; 177 static PerfCounter* _sync_JNIDefineClassLockFreeCounter; 178 179 static PerfCounter* _unsafe_defineClassCallCounter; 180 static PerfCounter* _isUnsyncloadClass; 181 static PerfCounter* _load_instance_class_failCounter; 182 183 // First entry in linked list of ClassPathEntry instances 184 static ClassPathEntry* _first_entry; 185 // Last entry in linked list of ClassPathEntry instances 186 static ClassPathEntry* _last_entry; 187 // Hash table used to keep track of loaded packages 188 static PackageHashtable* _package_hash_table; 189 static const char* _shared_archive; 190 191 // Hash function 192 static unsigned int hash(const char *s, int n); 193 // Returns the package file name corresponding to the specified package 194 // or class name, or null if not found. 195 static PackageInfo* lookup_package(const char *pkgname); 196 // Adds a new package entry for the specified class or package name and 197 // corresponding directory or jar file name. 198 static bool add_package(const char *pkgname, int classpath_index, TRAPS); 199 200 // Initialization 201 static void setup_meta_index(); 202 static void setup_bootstrap_search_path(); 203 static void load_zip_library(); 204 static void create_class_path_entry(char *path, struct stat st, ClassPathEntry **new_entry, bool lazy); 205 206 // Canonicalizes path names, so strcmp will work properly. This is mainly 207 // to avoid confusing the zip library 208 static bool get_canonical_path(char* orig, char* out, int len); 209 public: 210 // Used by the kernel jvm. 211 static void update_class_path_entry_list(const char *path, 212 bool check_for_duplicates); 213 static void print_bootclasspath(); 214 215 // Timing 216 static PerfCounter* perf_accumulated_time() { return _perf_accumulated_time; } 217 static PerfCounter* perf_classes_inited() { return _perf_classes_inited; } 218 static PerfCounter* perf_class_init_time() { return _perf_class_init_time; } 219 static PerfCounter* perf_class_init_selftime() { return _perf_class_init_selftime; } 220 static PerfCounter* perf_classes_verified() { return _perf_classes_verified; } 221 static PerfCounter* perf_class_verify_time() { return _perf_class_verify_time; } 222 static PerfCounter* perf_class_verify_selftime() { return _perf_class_verify_selftime; } 223 static PerfCounter* perf_classes_linked() { return _perf_classes_linked; } 224 static PerfCounter* perf_class_link_time() { return _perf_class_link_time; } 225 static PerfCounter* perf_class_link_selftime() { return _perf_class_link_selftime; } 226 static PerfCounter* perf_class_parse_time() { return _perf_class_parse_time; } 227 static PerfCounter* perf_class_parse_selftime() { return _perf_class_parse_selftime; } 228 static PerfCounter* perf_sys_class_lookup_time() { return _perf_sys_class_lookup_time; } 229 static PerfCounter* perf_shared_classload_time() { return _perf_shared_classload_time; } 230 static PerfCounter* perf_sys_classload_time() { return _perf_sys_classload_time; } 231 static PerfCounter* perf_app_classload_time() { return _perf_app_classload_time; } 232 static PerfCounter* perf_app_classload_selftime() { return _perf_app_classload_selftime; } 233 static PerfCounter* perf_app_classload_count() { return _perf_app_classload_count; } 234 static PerfCounter* perf_define_appclasses() { return _perf_define_appclasses; } 235 static PerfCounter* perf_define_appclass_time() { return _perf_define_appclass_time; } 236 static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; } 237 static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; } 238 static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; } 239 240 // Record how often system loader lock object is contended 241 static PerfCounter* sync_systemLoaderLockContentionRate() { 242 return _sync_systemLoaderLockContentionRate; 243 } 244 245 // Record how often non system loader lock object is contended 246 static PerfCounter* sync_nonSystemLoaderLockContentionRate() { 247 return _sync_nonSystemLoaderLockContentionRate; 248 } 249 250 // Record how many calls to JVM_FindLoadedClass w/o holding a lock 251 static PerfCounter* sync_JVMFindLoadedClassLockFreeCounter() { 252 return _sync_JVMFindLoadedClassLockFreeCounter; 253 } 254 255 // Record how many calls to JVM_DefineClass w/o holding a lock 256 static PerfCounter* sync_JVMDefineClassLockFreeCounter() { 257 return _sync_JVMDefineClassLockFreeCounter; 258 } 259 260 // Record how many calls to jni_DefineClass w/o holding a lock 261 static PerfCounter* sync_JNIDefineClassLockFreeCounter() { 262 return _sync_JNIDefineClassLockFreeCounter; 263 } 264 265 // Record how many calls to Unsafe_DefineClass 266 static PerfCounter* unsafe_defineClassCallCounter() { 267 return _unsafe_defineClassCallCounter; 268 } 269 270 // Record how many times SystemDictionary::load_instance_class call 271 // fails with linkageError when Unsyncloadclass flag is set. 272 static PerfCounter* load_instance_class_failCounter() { 273 return _load_instance_class_failCounter; 274 } 275 276 // Load individual .class file 277 static instanceKlassHandle load_classfile(symbolHandle h_name, TRAPS); 278 279 // If the specified package has been loaded by the system, then returns 280 // the name of the directory or ZIP file that the package was loaded from. 281 // Returns null if the package was not loaded. 282 // Note: The specified name can either be the name of a class or package. 283 // If a package name is specified, then it must be "/"-separator and also 284 // end with a trailing "/". 285 static oop get_system_package(const char* name, TRAPS); 286 287 // Returns an array of Java strings representing all of the currently 288 // loaded system packages. 289 // Note: The package names returned are "/"-separated and end with a 290 // trailing "/". 291 static objArrayOop get_system_packages(TRAPS); 292 293 // Initialization 294 static void initialize(); 295 static void create_package_info_table(); 296 static void create_package_info_table(HashtableBucket *t, int length, 297 int number_of_entries); 298 static int compute_Object_vtable(); 299 300 static ClassPathEntry* classpath_entry(int n) { 301 ClassPathEntry* e = ClassLoader::_first_entry; 302 while (--n >= 0) { 303 assert(e != NULL, "Not that many classpath entries."); 304 e = e->next(); 305 } 306 return e; 307 } 308 309 // Sharing dump and restore 310 static void copy_package_info_buckets(char** top, char* end); 311 static void copy_package_info_table(char** top, char* end); 312 313 // VM monitoring and management support 314 static jlong classloader_time_ms(); 315 static jlong class_method_total_size(); 316 static jlong class_init_count(); 317 static jlong class_init_time_ms(); 318 static jlong class_verify_time_ms(); 319 static jlong class_link_count(); 320 static jlong class_link_time_ms(); 321 322 // indicates if class path already contains a entry (exact match by name) 323 static bool contains_entry(ClassPathEntry* entry); 324 325 // adds a class path list 326 static void add_to_list(ClassPathEntry* new_entry); 327 328 // creates a class path zip entry (returns NULL if JAR file cannot be opened) 329 static ClassPathZipEntry* create_class_path_zip_entry(const char *apath); 330 331 // Debugging 332 static void verify() PRODUCT_RETURN; 333 334 // Force compilation of all methods in all classes in bootstrap class path (stress test) 335#ifndef PRODUCT 336 private: 337 static int _compile_the_world_counter; 338 public: 339 static void compile_the_world(); 340 static void compile_the_world_in(char* name, Handle loader, TRAPS); 341 static int compile_the_world_counter() { return _compile_the_world_counter; } 342#endif //PRODUCT 343}; 344 345// PerfClassTraceTime is used to measure time for class loading related events. 346// This class tracks cumulative time and exclusive time for specific event types. 347// During the execution of one event, other event types (e.g. class loading and 348// resolution) as well as recursive calls of the same event type could happen. 349// Only one elapsed timer (cumulative) and one thread-local self timer (exclusive) 350// (i.e. only one event type) are active at a time even multiple PerfClassTraceTime 351// instances have been created as multiple events are happening. 352class PerfClassTraceTime { 353 public: 354 enum { 355 CLASS_LOAD = 0, 356 PARSE_CLASS = 1, 357 CLASS_LINK = 2, 358 CLASS_VERIFY = 3, 359 CLASS_CLINIT = 4, 360 DEFINE_CLASS = 5, 361 EVENT_TYPE_COUNT = 6 362 }; 363 protected: 364 // _t tracks time from initialization to destruction of this timer instance 365 // including time for all other event types, and recursive calls of this type. 366 // When a timer is called recursively, the elapsedTimer _t would not be used. 367 elapsedTimer _t; 368 PerfLongCounter* _timep; 369 PerfLongCounter* _selftimep; 370 PerfLongCounter* _eventp; 371 // pointer to thread-local recursion counter and timer array 372 // The thread_local timers track cumulative time for specific event types 373 // exclusive of time for other event types, but including recursive calls 374 // of the same type. 375 int* _recursion_counters; 376 elapsedTimer* _timers; 377 int _event_type; 378 int _prev_active_event; 379 380 public: 381 382 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */ 383 PerfLongCounter* selftimep, /* counter incremented with exclusive time */ 384 PerfLongCounter* eventp, /* event counter */ 385 int* recursion_counters, /* thread-local recursion counter array */ 386 elapsedTimer* timers, /* thread-local timer array */ 387 int type /* event type */ ) : 388 _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) { 389 initialize(); 390 } 391 392 inline PerfClassTraceTime(PerfLongCounter* timep, /* counter incremented with inclusive time */ 393 elapsedTimer* timers, /* thread-local timer array */ 394 int type /* event type */ ) : 395 _timep(timep), _selftimep(NULL), _eventp(NULL), _recursion_counters(NULL), _timers(timers), _event_type(type) { 396 initialize(); 397 } 398 399 void initialize() { 400 if (!UsePerfData) return; 401 402 if (_eventp != NULL) { 403 // increment the event counter 404 _eventp->inc(); 405 } 406 407 // stop the current active thread-local timer to measure inclusive time 408 _prev_active_event = -1; 409 for (int i=0; i < EVENT_TYPE_COUNT; i++) { 410 if (_timers[i].is_active()) { 411 assert(_prev_active_event == -1, "should have only one active timer"); 412 _prev_active_event = i; 413 _timers[i].stop(); 414 } 415 } 416 417 if (_recursion_counters == NULL || (_recursion_counters[_event_type])++ == 0) { 418 // start the inclusive timer if not recursively called 419 _t.start(); 420 } 421 422 // start thread-local timer of the given event type 423 if (!_timers[_event_type].is_active()) { 424 _timers[_event_type].start(); 425 } 426 } 427 428 inline void suspend() { _t.stop(); _timers[_event_type].stop(); } 429 inline void resume() { _t.start(); _timers[_event_type].start(); } 430 431 ~PerfClassTraceTime() { 432 if (!UsePerfData) return; 433 434 // stop the thread-local timer as the event completes 435 // and resume the thread-local timer of the event next on the stack 436 _timers[_event_type].stop(); 437 jlong selftime = _timers[_event_type].ticks(); 438 439 if (_prev_active_event >= 0) { 440 _timers[_prev_active_event].start(); 441 } 442 443 if (_recursion_counters != NULL && --(_recursion_counters[_event_type]) > 0) return; 444 445 // increment the counters only on the leaf call 446 _t.stop(); 447 _timep->inc(_t.ticks()); 448 if (_selftimep != NULL) { 449 _selftimep->inc(selftime); 450 } 451 // add all class loading related event selftime to the accumulated time counter 452 ClassLoader::perf_accumulated_time()->inc(selftime); 453 454 // reset the timer 455 _timers[_event_type].reset(); 456 } 457}; 458 459