1 /*
   2  * Copyright (c) 1997, 2010, 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 #ifndef SHARE_VM_CLASSFILE_CLASSLOADER_HPP
  26 #define SHARE_VM_CLASSFILE_CLASSLOADER_HPP
  27 
  28 #include "classfile/classFileParser.hpp"
  29 #include "runtime/perfData.hpp"
  30 
  31 // The VM class loader.
  32 #include <sys/stat.h>
  33 
  34 
  35 // Meta-index (optional, to be able to skip opening boot classpath jar files)
  36 class MetaIndex: public CHeapObj {
  37  private:
  38   char** _meta_package_names;
  39   int    _num_meta_package_names;
  40  public:
  41   MetaIndex(char** meta_package_names, int num_meta_package_names);
  42   ~MetaIndex();
  43   bool may_contain(const char* class_name);
  44 };
  45 
  46 
  47 // Class path entry (directory or zip file)
  48 
  49 class ClassPathEntry: public CHeapObj {
  50  private:
  51   ClassPathEntry* _next;
  52  public:
  53   // Next entry in class path
  54   ClassPathEntry* next()              { return _next; }
  55   void set_next(ClassPathEntry* next) {
  56     // may have unlocked readers, so write atomically.
  57     OrderAccess::release_store_ptr(&_next, next);
  58   }
  59   virtual bool is_jar_file() = 0;
  60   virtual const char* name() = 0;
  61   virtual bool is_lazy();
  62   // Constructor
  63   ClassPathEntry();
  64   // Attempt to locate file_name through this class path entry.
  65   // Returns a class file parsing stream if successfull.
  66   virtual ClassFileStream* open_stream(const char* name) = 0;
  67   // Debugging
  68   NOT_PRODUCT(virtual void compile_the_world(Handle loader, TRAPS) = 0;)
  69   NOT_PRODUCT(virtual bool is_rt_jar() = 0;)
  70 };
  71 
  72 
  73 class ClassPathDirEntry: public ClassPathEntry {
  74  private:
  75   char* _dir;           // Name of directory
  76  public:
  77   bool is_jar_file()  { return false;  }
  78   const char* name()  { return _dir; }
  79   ClassPathDirEntry(char* dir);
  80   ClassFileStream* open_stream(const char* name);
  81   // Debugging
  82   NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
  83   NOT_PRODUCT(bool is_rt_jar();)
  84 };
  85 
  86 
  87 // Type definitions for zip file and zip file entry
  88 typedef void* jzfile;
  89 typedef struct {
  90   char *name;                   /* entry name */
  91   jlong time;                   /* modification time */
  92   jlong size;                   /* size of uncompressed data */
  93   jlong csize;                  /* size of compressed data (zero if uncompressed) */
  94   jint crc;                     /* crc of uncompressed data */
  95   char *comment;                /* optional zip file comment */
  96   jbyte *extra;                 /* optional extra data */
  97   jlong pos;                    /* position of LOC header (if negative) or data */
  98 } jzentry;
  99 
 100 
 101 class ClassPathZipEntry: public ClassPathEntry {
 102  private:
 103   jzfile* _zip;        // The zip archive
 104   char*   _zip_name;   // Name of zip archive
 105  public:
 106   bool is_jar_file()  { return true;  }
 107   const char* name()  { return _zip_name; }
 108   ClassPathZipEntry(jzfile* zip, const char* zip_name);
 109   ~ClassPathZipEntry();
 110   ClassFileStream* open_stream(const char* name);
 111   void contents_do(void f(const char* name, void* context), void* context);
 112   // Debugging
 113   NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
 114   NOT_PRODUCT(void compile_the_world12(Handle loader, TRAPS);) // JDK 1.2 version
 115   NOT_PRODUCT(void compile_the_world13(Handle loader, TRAPS);) // JDK 1.3 version
 116   NOT_PRODUCT(bool is_rt_jar();)
 117   NOT_PRODUCT(bool is_rt_jar12();)
 118   NOT_PRODUCT(bool is_rt_jar13();)
 119 };
 120 
 121 
 122 // For lazier loading of boot class path entries
 123 class LazyClassPathEntry: public ClassPathEntry {
 124  private:
 125   char* _path; // dir or file
 126   struct stat _st;
 127   MetaIndex* _meta_index;
 128   volatile ClassPathEntry* _resolved_entry;
 129   ClassPathEntry* resolve_entry();
 130  public:
 131   bool is_jar_file();
 132   const char* name()  { return _path; }
 133   LazyClassPathEntry(char* path, struct stat st);
 134   ClassFileStream* open_stream(const char* name);
 135   void set_meta_index(MetaIndex* meta_index) { _meta_index = meta_index; }
 136   virtual bool is_lazy();
 137   // Debugging
 138   NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
 139   NOT_PRODUCT(bool is_rt_jar();)
 140 };
 141 
 142 class PackageHashtable;
 143 class PackageInfo;
 144 class HashtableBucket;
 145 
 146 class ClassLoader: AllStatic {
 147  public:
 148   enum SomeConstants {
 149     package_hash_table_size = 31  // Number of buckets
 150   };
 151  private:
 152   friend class LazyClassPathEntry;
 153 
 154   // Performance counters
 155   static PerfCounter* _perf_accumulated_time;
 156   static PerfCounter* _perf_classes_inited;
 157   static PerfCounter* _perf_class_init_time;
 158   static PerfCounter* _perf_class_init_selftime;
 159   static PerfCounter* _perf_classes_verified;
 160   static PerfCounter* _perf_class_verify_time;
 161   static PerfCounter* _perf_class_verify_selftime;
 162   static PerfCounter* _perf_classes_linked;
 163   static PerfCounter* _perf_class_link_time;
 164   static PerfCounter* _perf_class_link_selftime;
 165   static PerfCounter* _perf_class_parse_time;
 166   static PerfCounter* _perf_class_parse_selftime;
 167   static PerfCounter* _perf_sys_class_lookup_time;
 168   static PerfCounter* _perf_shared_classload_time;
 169   static PerfCounter* _perf_sys_classload_time;
 170   static PerfCounter* _perf_app_classload_time;
 171   static PerfCounter* _perf_app_classload_selftime;
 172   static PerfCounter* _perf_app_classload_count;
 173   static PerfCounter* _perf_define_appclasses;
 174   static PerfCounter* _perf_define_appclass_time;
 175   static PerfCounter* _perf_define_appclass_selftime;
 176   static PerfCounter* _perf_app_classfile_bytes_read;
 177   static PerfCounter* _perf_sys_classfile_bytes_read;
 178 
 179   static PerfCounter* _sync_systemLoaderLockContentionRate;
 180   static PerfCounter* _sync_nonSystemLoaderLockContentionRate;
 181   static PerfCounter* _sync_JVMFindLoadedClassLockFreeCounter;
 182   static PerfCounter* _sync_JVMDefineClassLockFreeCounter;
 183   static PerfCounter* _sync_JNIDefineClassLockFreeCounter;
 184 
 185   static PerfCounter* _unsafe_defineClassCallCounter;
 186   static PerfCounter* _isUnsyncloadClass;
 187   static PerfCounter* _load_instance_class_failCounter;
 188 
 189   // First entry in linked list of ClassPathEntry instances
 190   static ClassPathEntry* _first_entry;
 191   // Last entry in linked list of ClassPathEntry instances
 192   static ClassPathEntry* _last_entry;
 193   // Hash table used to keep track of loaded packages
 194   static PackageHashtable* _package_hash_table;
 195   static const char* _shared_archive;
 196 
 197   // Hash function
 198   static unsigned int hash(const char *s, int n);
 199   // Returns the package file name corresponding to the specified package
 200   // or class name, or null if not found.
 201   static PackageInfo* lookup_package(const char *pkgname);
 202   // Adds a new package entry for the specified class or package name and
 203   // corresponding directory or jar file name.
 204   static bool add_package(const char *pkgname, int classpath_index, TRAPS);
 205 
 206   // Initialization
 207   static void setup_meta_index();
 208   static void setup_bootstrap_search_path();
 209   static void load_zip_library();
 210   static void create_class_path_entry(char *path, struct stat st, ClassPathEntry **new_entry, bool lazy);
 211 
 212   // Canonicalizes path names, so strcmp will work properly. This is mainly
 213   // to avoid confusing the zip library
 214   static bool get_canonical_path(char* orig, char* out, int len);
 215  public:
 216   // Used by the kernel jvm.
 217   static void update_class_path_entry_list(const char *path,
 218                                            bool check_for_duplicates);
 219   static void print_bootclasspath();
 220 
 221   // Timing
 222   static PerfCounter* perf_accumulated_time()         { return _perf_accumulated_time; }
 223   static PerfCounter* perf_classes_inited()           { return _perf_classes_inited; }
 224   static PerfCounter* perf_class_init_time()          { return _perf_class_init_time; }
 225   static PerfCounter* perf_class_init_selftime()      { return _perf_class_init_selftime; }
 226   static PerfCounter* perf_classes_verified()         { return _perf_classes_verified; }
 227   static PerfCounter* perf_class_verify_time()        { return _perf_class_verify_time; }
 228   static PerfCounter* perf_class_verify_selftime()    { return _perf_class_verify_selftime; }
 229   static PerfCounter* perf_classes_linked()           { return _perf_classes_linked; }
 230   static PerfCounter* perf_class_link_time()          { return _perf_class_link_time; }
 231   static PerfCounter* perf_class_link_selftime()      { return _perf_class_link_selftime; }
 232   static PerfCounter* perf_class_parse_time()         { return _perf_class_parse_time; }
 233   static PerfCounter* perf_class_parse_selftime()     { return _perf_class_parse_selftime; }
 234   static PerfCounter* perf_sys_class_lookup_time()    { return _perf_sys_class_lookup_time; }
 235   static PerfCounter* perf_shared_classload_time()    { return _perf_shared_classload_time; }
 236   static PerfCounter* perf_sys_classload_time()       { return _perf_sys_classload_time; }
 237   static PerfCounter* perf_app_classload_time()       { return _perf_app_classload_time; }
 238   static PerfCounter* perf_app_classload_selftime()   { return _perf_app_classload_selftime; }
 239   static PerfCounter* perf_app_classload_count()      { return _perf_app_classload_count; }
 240   static PerfCounter* perf_define_appclasses()        { return _perf_define_appclasses; }
 241   static PerfCounter* perf_define_appclass_time()     { return _perf_define_appclass_time; }
 242   static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; }
 243   static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; }
 244   static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; }
 245 
 246   // Record how often system loader lock object is contended
 247   static PerfCounter* sync_systemLoaderLockContentionRate() {
 248     return _sync_systemLoaderLockContentionRate;
 249   }
 250 
 251   // Record how often non system loader lock object is contended
 252   static PerfCounter* sync_nonSystemLoaderLockContentionRate() {
 253     return _sync_nonSystemLoaderLockContentionRate;
 254   }
 255 
 256   // Record how many calls to JVM_FindLoadedClass w/o holding a lock
 257   static PerfCounter* sync_JVMFindLoadedClassLockFreeCounter() {
 258     return _sync_JVMFindLoadedClassLockFreeCounter;
 259   }
 260 
 261   // Record how many calls to JVM_DefineClass w/o holding a lock
 262   static PerfCounter* sync_JVMDefineClassLockFreeCounter() {
 263     return _sync_JVMDefineClassLockFreeCounter;
 264   }
 265 
 266   // Record how many calls to jni_DefineClass w/o holding a lock
 267   static PerfCounter* sync_JNIDefineClassLockFreeCounter() {
 268     return _sync_JNIDefineClassLockFreeCounter;
 269   }
 270 
 271   // Record how many calls to Unsafe_DefineClass
 272   static PerfCounter* unsafe_defineClassCallCounter() {
 273     return _unsafe_defineClassCallCounter;
 274   }
 275 
 276   // Record how many times SystemDictionary::load_instance_class call
 277   // fails with linkageError when Unsyncloadclass flag is set.
 278   static PerfCounter* load_instance_class_failCounter() {
 279     return _load_instance_class_failCounter;
 280   }
 281 
 282   // Load individual .class file
 283   static instanceKlassHandle load_classfile(symbolHandle h_name, TRAPS);
 284 
 285   // If the specified package has been loaded by the system, then returns
 286   // the name of the directory or ZIP file that the package was loaded from.
 287   // Returns null if the package was not loaded.
 288   // Note: The specified name can either be the name of a class or package.
 289   // If a package name is specified, then it must be "/"-separator and also
 290   // end with a trailing "/".
 291   static oop get_system_package(const char* name, TRAPS);
 292 
 293   // Returns an array of Java strings representing all of the currently
 294   // loaded system packages.
 295   // Note: The package names returned are "/"-separated and end with a
 296   // trailing "/".
 297   static objArrayOop get_system_packages(TRAPS);
 298 
 299   // Initialization
 300   static void initialize();
 301   static void create_package_info_table();
 302   static void create_package_info_table(HashtableBucket *t, int length,
 303                                         int number_of_entries);
 304   static int compute_Object_vtable();
 305 
 306   static ClassPathEntry* classpath_entry(int n) {
 307     ClassPathEntry* e = ClassLoader::_first_entry;
 308     while (--n >= 0) {
 309       assert(e != NULL, "Not that many classpath entries.");
 310       e = e->next();
 311     }
 312     return e;
 313   }
 314 
 315   // Sharing dump and restore
 316   static void copy_package_info_buckets(char** top, char* end);
 317   static void copy_package_info_table(char** top, char* end);
 318 
 319   // VM monitoring and management support
 320   static jlong classloader_time_ms();
 321   static jlong class_method_total_size();
 322   static jlong class_init_count();
 323   static jlong class_init_time_ms();
 324   static jlong class_verify_time_ms();
 325   static jlong class_link_count();
 326   static jlong class_link_time_ms();
 327 
 328   // indicates if class path already contains a entry (exact match by name)
 329   static bool contains_entry(ClassPathEntry* entry);
 330 
 331   // adds a class path list
 332   static void add_to_list(ClassPathEntry* new_entry);
 333 
 334   // creates a class path zip entry (returns NULL if JAR file cannot be opened)
 335   static ClassPathZipEntry* create_class_path_zip_entry(const char *apath);
 336 
 337   // Debugging
 338   static void verify()              PRODUCT_RETURN;
 339 
 340   // Force compilation of all methods in all classes in bootstrap class path (stress test)
 341 #ifndef PRODUCT
 342  private:
 343   static int _compile_the_world_counter;
 344  public:
 345   static void compile_the_world();
 346   static void compile_the_world_in(char* name, Handle loader, TRAPS);
 347   static int  compile_the_world_counter() { return _compile_the_world_counter; }
 348 #endif //PRODUCT
 349 };
 350 
 351 // PerfClassTraceTime is used to measure time for class loading related events.
 352 // This class tracks cumulative time and exclusive time for specific event types.
 353 // During the execution of one event, other event types (e.g. class loading and
 354 // resolution) as well as recursive calls of the same event type could happen.
 355 // Only one elapsed timer (cumulative) and one thread-local self timer (exclusive)
 356 // (i.e. only one event type) are active at a time even multiple PerfClassTraceTime
 357 // instances have been created as multiple events are happening.
 358 class PerfClassTraceTime {
 359   public:
 360     enum {
 361        CLASS_LOAD   = 0,
 362        PARSE_CLASS  = 1,
 363        CLASS_LINK   = 2,
 364        CLASS_VERIFY = 3,
 365        CLASS_CLINIT = 4,
 366        DEFINE_CLASS = 5,
 367        EVENT_TYPE_COUNT = 6
 368     };
 369   protected:
 370     // _t tracks time from initialization to destruction of this timer instance
 371     // including time for all other event types, and recursive calls of this type.
 372     // When a timer is called recursively, the elapsedTimer _t would not be used.
 373     elapsedTimer     _t;
 374     PerfLongCounter* _timep;
 375     PerfLongCounter* _selftimep;
 376     PerfLongCounter* _eventp;
 377     // pointer to thread-local recursion counter and timer array
 378     // The thread_local timers track cumulative time for specific event types
 379     // exclusive of time for other event types, but including recursive calls
 380     // of the same type.
 381     int*             _recursion_counters;
 382     elapsedTimer*    _timers;
 383     int              _event_type;
 384     int              _prev_active_event;
 385 
 386   public:
 387 
 388     inline PerfClassTraceTime(PerfLongCounter* timep,     /* counter incremented with inclusive time */
 389                               PerfLongCounter* selftimep, /* counter incremented with exclusive time */
 390                               PerfLongCounter* eventp,    /* event counter */
 391                               int* recursion_counters,    /* thread-local recursion counter array */
 392                               elapsedTimer* timers,       /* thread-local timer array */
 393                               int type                    /* event type */ ) :
 394         _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) {
 395       initialize();
 396     }
 397 
 398     inline PerfClassTraceTime(PerfLongCounter* timep,     /* counter incremented with inclusive time */
 399                               elapsedTimer* timers,       /* thread-local timer array */
 400                               int type                    /* event type */ ) :
 401         _timep(timep), _selftimep(NULL), _eventp(NULL), _recursion_counters(NULL), _timers(timers), _event_type(type) {
 402       initialize();
 403     }
 404 
 405     void initialize() {
 406       if (!UsePerfData) return;
 407 
 408       if (_eventp != NULL) {
 409         // increment the event counter
 410         _eventp->inc();
 411       }
 412 
 413       // stop the current active thread-local timer to measure inclusive time
 414       _prev_active_event = -1;
 415       for (int i=0; i < EVENT_TYPE_COUNT; i++) {
 416          if (_timers[i].is_active()) {
 417            assert(_prev_active_event == -1, "should have only one active timer");
 418            _prev_active_event = i;
 419            _timers[i].stop();
 420          }
 421       }
 422 
 423       if (_recursion_counters == NULL || (_recursion_counters[_event_type])++ == 0) {
 424         // start the inclusive timer if not recursively called
 425         _t.start();
 426       }
 427 
 428       // start thread-local timer of the given event type
 429       if (!_timers[_event_type].is_active()) {
 430         _timers[_event_type].start();
 431       }
 432     }
 433 
 434     inline void suspend() { _t.stop(); _timers[_event_type].stop(); }
 435     inline void resume()  { _t.start(); _timers[_event_type].start(); }
 436 
 437     ~PerfClassTraceTime() {
 438       if (!UsePerfData) return;
 439 
 440       // stop the thread-local timer as the event completes
 441       // and resume the thread-local timer of the event next on the stack
 442       _timers[_event_type].stop();
 443       jlong selftime = _timers[_event_type].ticks();
 444 
 445       if (_prev_active_event >= 0) {
 446         _timers[_prev_active_event].start();
 447       }
 448 
 449       if (_recursion_counters != NULL && --(_recursion_counters[_event_type]) > 0) return;
 450 
 451       // increment the counters only on the leaf call
 452       _t.stop();
 453       _timep->inc(_t.ticks());
 454       if (_selftimep != NULL) {
 455         _selftimep->inc(selftime);
 456       }
 457       // add all class loading related event selftime to the accumulated time counter
 458       ClassLoader::perf_accumulated_time()->inc(selftime);
 459 
 460       // reset the timer
 461       _timers[_event_type].reset();
 462     }
 463 };
 464 
 465 
 466 #endif // SHARE_VM_CLASSFILE_CLASSLOADER_HPP