1 /*
2 * Copyright (c) 1997, 2009, 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 // The VM class loader.
26 #include <sys/stat.h>
27
28
29 // Meta-index (optional, to be able to skip opening boot classpath jar files)
30 class MetaIndex: public CHeapObj {
31 private:
32 char** _meta_package_names;
33 int _num_meta_package_names;
34 public:
35 MetaIndex(char** meta_package_names, int num_meta_package_names);
36 ~MetaIndex();
37 bool may_contain(const char* class_name);
38 };
39
40
41 // Class path entry (directory or zip file)
42
43 class ClassPathEntry: public CHeapObj {
44 private:
45 ClassPathEntry* _next;
46 public:
47 // Next entry in class path
48 ClassPathEntry* next() { return _next; }
49 void set_next(ClassPathEntry* next) {
50 // may have unlocked readers, so write atomically.
51 OrderAccess::release_store_ptr(&_next, next);
52 }
53 virtual bool is_jar_file() = 0;
54 virtual const char* name() = 0;
55 virtual bool is_lazy();
56 // Constructor
57 ClassPathEntry();
58 // Attempt to locate file_name through this class path entry.
59 // Returns a class file parsing stream if successfull.
60 virtual ClassFileStream* open_stream(const char* name) = 0;
61 // Debugging
62 NOT_PRODUCT(virtual void compile_the_world(Handle loader, TRAPS) = 0;)
63 NOT_PRODUCT(virtual bool is_rt_jar() = 0;)
64 };
65
66
67 class ClassPathDirEntry: public ClassPathEntry {
68 private:
69 char* _dir; // Name of directory
70 public:
71 bool is_jar_file() { return false; }
72 const char* name() { return _dir; }
73 ClassPathDirEntry(char* dir);
74 ClassFileStream* open_stream(const char* name);
75 // Debugging
76 NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
77 NOT_PRODUCT(bool is_rt_jar();)
78 };
79
80
81 // Type definitions for zip file and zip file entry
82 typedef void* jzfile;
83 typedef struct {
84 char *name; /* entry name */
85 jlong time; /* modification time */
86 jlong size; /* size of uncompressed data */
87 jlong csize; /* size of compressed data (zero if uncompressed) */
88 jint crc; /* crc of uncompressed data */
89 char *comment; /* optional zip file comment */
90 jbyte *extra; /* optional extra data */
91 jlong pos; /* position of LOC header (if negative) or data */
92 } jzentry;
93
94
95 class ClassPathZipEntry: public ClassPathEntry {
96 private:
97 jzfile* _zip; // The zip archive
98 char* _zip_name; // Name of zip archive
99 public:
100 bool is_jar_file() { return true; }
101 const char* name() { return _zip_name; }
102 ClassPathZipEntry(jzfile* zip, const char* zip_name);
103 ~ClassPathZipEntry();
104 ClassFileStream* open_stream(const char* name);
105 void contents_do(void f(const char* name, void* context), void* context);
106 // Debugging
107 NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
108 NOT_PRODUCT(void compile_the_world12(Handle loader, TRAPS);) // JDK 1.2 version
109 NOT_PRODUCT(void compile_the_world13(Handle loader, TRAPS);) // JDK 1.3 version
110 NOT_PRODUCT(bool is_rt_jar();)
111 NOT_PRODUCT(bool is_rt_jar12();)
112 NOT_PRODUCT(bool is_rt_jar13();)
113 };
114
115
116 // For lazier loading of boot class path entries
117 class LazyClassPathEntry: public ClassPathEntry {
118 private:
119 char* _path; // dir or file
120 struct stat _st;
121 MetaIndex* _meta_index;
122 volatile ClassPathEntry* _resolved_entry;
123 ClassPathEntry* resolve_entry();
124 public:
125 bool is_jar_file();
126 const char* name() { return _path; }
127 LazyClassPathEntry(char* path, struct stat st);
128 ClassFileStream* open_stream(const char* name);
129 void set_meta_index(MetaIndex* meta_index) { _meta_index = meta_index; }
130 virtual bool is_lazy();
131 // Debugging
132 NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
133 NOT_PRODUCT(bool is_rt_jar();)
134 };
135
136 class PackageHashtable;
137 class PackageInfo;
138 class HashtableBucket;
139
140 class ClassLoader: AllStatic {
141 public:
142 enum SomeConstants {
143 package_hash_table_size = 31 // Number of buckets
144 };
145 private:
146 friend class LazyClassPathEntry;
147
148 // Performance counters
149 static PerfCounter* _perf_accumulated_time;
150 static PerfCounter* _perf_classes_inited;
151 static PerfCounter* _perf_class_init_time;
152 static PerfCounter* _perf_class_init_selftime;
153 static PerfCounter* _perf_classes_verified;
154 static PerfCounter* _perf_class_verify_time;
155 static PerfCounter* _perf_class_verify_selftime;
156 static PerfCounter* _perf_classes_linked;
157 static PerfCounter* _perf_class_link_time;
158 static PerfCounter* _perf_class_link_selftime;
159 static PerfCounter* _perf_class_parse_time;
160 static PerfCounter* _perf_class_parse_selftime;
161 static PerfCounter* _perf_sys_class_lookup_time;
162 static PerfCounter* _perf_shared_classload_time;
163 static PerfCounter* _perf_sys_classload_time;
164 static PerfCounter* _perf_app_classload_time;
165 static PerfCounter* _perf_app_classload_selftime;
166 static PerfCounter* _perf_app_classload_count;
167 static PerfCounter* _perf_define_appclasses;
168 static PerfCounter* _perf_define_appclass_time;
169 static PerfCounter* _perf_define_appclass_selftime;
170 static PerfCounter* _perf_app_classfile_bytes_read;
171 static PerfCounter* _perf_sys_classfile_bytes_read;
172
173 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.
352 class 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