1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   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.
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   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).
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  20  * or visit www.oracle.com if you need additional information or have any
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  24 
  25 #ifndef SHARE_VM_CLASSFILE_DICTIONARY_HPP
  26 #define SHARE_VM_CLASSFILE_DICTIONARY_HPP
  27 
  28 #include "classfile/systemDictionary.hpp"
  29 #include "oops/instanceKlass.hpp"
  30 #include "oops/oop.hpp"
  31 #include "utilities/hashtable.hpp"
  32 
  33 class DictionaryEntry;
  34 class PSPromotionManager;
  35 class ProtectionDomainCacheTable;
  36 class ProtectionDomainCacheEntry;
  37 class BoolObjectClosure;
  38 
  39 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  40 // The data structure for the system dictionary (and the shared system
  41 // dictionary).
  42 
  43 class Dictionary : public TwoOopHashtable<Klass*, mtClass> {
  44   friend class VMStructs;
  45 private:
  46   // current iteration index.
  47   static int                    _current_class_index;
  48   // pointer to the current hash table entry.
  49   static DictionaryEntry*       _current_class_entry;
  50 
  51   ProtectionDomainCacheTable*   _pd_cache_table;
  52 
  53   DictionaryEntry* get_entry(int index, unsigned int hash,
  54                              Symbol* name, ClassLoaderData* loader_data);
  55 
  56   DictionaryEntry* bucket(int i) {
  57     return (DictionaryEntry*)Hashtable<Klass*, mtClass>::bucket(i);
  58   }
  59 
  60   // The following method is not MT-safe and must be done under lock.
  61   DictionaryEntry** bucket_addr(int i) {
  62     return (DictionaryEntry**)Hashtable<Klass*, mtClass>::bucket_addr(i);
  63   }
  64 
  65   void add_entry(int index, DictionaryEntry* new_entry) {
  66     Hashtable<Klass*, mtClass>::add_entry(index, (HashtableEntry<Klass*, mtClass>*)new_entry);
  67   }
  68 
  69 public:
  70   Dictionary(int table_size);
  71   Dictionary(int table_size, HashtableBucket<mtClass>* t, int number_of_entries);
  72 
  73   DictionaryEntry* new_entry(unsigned int hash, Klass* klass, ClassLoaderData* loader_data);
  74 
  75   DictionaryEntry* new_entry();
  76 
  77   void free_entry(DictionaryEntry* entry);
  78 
  79   void add_klass(Symbol* class_name, ClassLoaderData* loader_data,KlassHandle obj);
  80 
  81   Klass* find_class(int index, unsigned int hash,
  82                       Symbol* name, ClassLoaderData* loader_data);
  83 
  84   Klass* find_shared_class(int index, unsigned int hash, Symbol* name);
  85 
  86   // Compiler support
  87   Klass* try_get_next_class();
  88 
  89   // GC support
  90   void oops_do(OopClosure* f);
  91   void always_strong_oops_do(OopClosure* blk);
  92   void roots_oops_do(OopClosure* strong, OopClosure* weak);
  93 
  94   void always_strong_classes_do(KlassClosure* closure);
  95 
  96   void classes_do(void f(Klass*));
  97   void classes_do(void f(Klass*, TRAPS), TRAPS);
  98   void classes_do(void f(Klass*, ClassLoaderData*));
  99 
 100   void methods_do(void f(Method*));
 101 
 102   void unlink(BoolObjectClosure* is_alive);
 103   void remove_classes_in_error_state();
 104 
 105   // Classes loaded by the bootstrap loader are always strongly reachable.
 106   // If we're not doing class unloading, all classes are strongly reachable.
 107   static bool is_strongly_reachable(ClassLoaderData* loader_data, Klass* klass) {
 108     assert (klass != NULL, "should have non-null klass");
 109     return (loader_data->is_the_null_class_loader_data() || !ClassUnloading);
 110   }
 111 
 112   // Unload (that is, break root links to) all unmarked classes and loaders.
 113   void do_unloading();
 114 
 115   // Protection domains
 116   Klass* find(int index, unsigned int hash, Symbol* name,
 117                 ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
 118   bool is_valid_protection_domain(int index, unsigned int hash,
 119                                   Symbol* name, ClassLoaderData* loader_data,
 120                                   Handle protection_domain);
 121   void add_protection_domain(int index, unsigned int hash,
 122                              instanceKlassHandle klass, ClassLoaderData* loader_data,
 123                              Handle protection_domain, TRAPS);
 124 
 125   // Sharing support
 126   void reorder_dictionary();
 127 
 128   ProtectionDomainCacheEntry* cache_get(oop protection_domain);
 129 
 130   void print(bool details = true);
 131   void verify();
 132 };
 133 
 134 // The following classes can be in dictionary.cpp, but we need these
 135 // to be in header file so that SA's vmStructs can access them.
 136 class ProtectionDomainCacheEntry : public HashtableEntry<oop, mtClass> {
 137   friend class VMStructs;
 138  private:
 139   // Flag indicating whether this protection domain entry is strongly reachable.
 140   // Used during iterating over the system dictionary to remember oops that need
 141   // to be updated.
 142   bool _strongly_reachable;
 143  public:
 144   oop protection_domain() { return literal(); }
 145 
 146   void init() {
 147     _strongly_reachable = false;
 148   }
 149 
 150   ProtectionDomainCacheEntry* next() {
 151     return (ProtectionDomainCacheEntry*)HashtableEntry<oop, mtClass>::next();
 152   }
 153 
 154   ProtectionDomainCacheEntry** next_addr() {
 155     return (ProtectionDomainCacheEntry**)HashtableEntry<oop, mtClass>::next_addr();
 156   }
 157 
 158   void oops_do(OopClosure* f) {
 159     f->do_oop(literal_addr());
 160   }
 161 
 162   void set_strongly_reachable()   { _strongly_reachable = true; }
 163   bool is_strongly_reachable()    { return _strongly_reachable; }
 164   void reset_strongly_reachable() { _strongly_reachable = false; }
 165 
 166   void print() PRODUCT_RETURN;
 167   void verify();
 168 };
 169 
 170 // The ProtectionDomainCacheTable contains all protection domain oops. The system
 171 // dictionary entries reference its entries instead of having references to oops
 172 // directly.
 173 // This is used to speed up system dictionary iteration: the oops in the
 174 // protection domain are the only ones referring the Java heap. So when there is
 175 // need to update these, instead of going over every entry of the system dictionary,
 176 // we only need to iterate over this set.
 177 // The amount of different protection domains used is typically magnitudes smaller
 178 // than the number of system dictionary entries (loaded classes).
 179 class ProtectionDomainCacheTable : public Hashtable<oop, mtClass> {
 180   friend class VMStructs;
 181 private:
 182   ProtectionDomainCacheEntry* bucket(int i) {
 183     return (ProtectionDomainCacheEntry*) Hashtable<oop, mtClass>::bucket(i);
 184   }
 185 
 186   // The following method is not MT-safe and must be done under lock.
 187   ProtectionDomainCacheEntry** bucket_addr(int i) {
 188     return (ProtectionDomainCacheEntry**) Hashtable<oop, mtClass>::bucket_addr(i);
 189   }
 190 
 191   ProtectionDomainCacheEntry* new_entry(unsigned int hash, oop protection_domain) {
 192     ProtectionDomainCacheEntry* entry = (ProtectionDomainCacheEntry*) Hashtable<oop, mtClass>::new_entry(hash, protection_domain);
 193     entry->init();
 194     return entry;
 195   }
 196 
 197   static unsigned int compute_hash(oop protection_domain) {
 198     return (unsigned int)(protection_domain->identity_hash());
 199   }
 200 
 201   int index_for(oop protection_domain) {
 202     return hash_to_index(compute_hash(protection_domain));
 203   }
 204 
 205   ProtectionDomainCacheEntry* add_entry(int index, unsigned int hash, oop protection_domain);
 206   ProtectionDomainCacheEntry* find_entry(int index, oop protection_domain);
 207 
 208 public:
 209 
 210   ProtectionDomainCacheTable(int table_size);
 211 
 212   ProtectionDomainCacheEntry* get(oop protection_domain);
 213   void free(ProtectionDomainCacheEntry* entry);
 214 
 215   void unlink(BoolObjectClosure* cl);
 216 
 217   // GC support
 218   void oops_do(OopClosure* f);
 219   void always_strong_oops_do(OopClosure* f);
 220   void roots_oops_do(OopClosure* strong, OopClosure* weak);
 221 
 222   static uint bucket_size();
 223 
 224   void print() PRODUCT_RETURN;
 225   void verify();
 226 };
 227 
 228 
 229 class ProtectionDomainEntry :public CHeapObj<mtClass> {
 230   friend class VMStructs;
 231  public:
 232   ProtectionDomainEntry* _next;
 233   ProtectionDomainCacheEntry* _pd_cache;
 234 
 235   ProtectionDomainEntry(ProtectionDomainCacheEntry* pd_cache, ProtectionDomainEntry* next) {
 236     _pd_cache = pd_cache;
 237     _next     = next;
 238   }
 239 
 240   ProtectionDomainEntry* next() { return _next; }
 241   oop protection_domain() { return _pd_cache->protection_domain(); }
 242 };
 243 
 244 // An entry in the system dictionary, this describes a class as
 245 // { Klass*, loader, protection_domain }.
 246 
 247 class DictionaryEntry : public HashtableEntry<Klass*, mtClass> {
 248   friend class VMStructs;
 249  private:
 250   // Contains the set of approved protection domains that can access
 251   // this system dictionary entry.
 252   //
 253   // This protection domain set is a set of tuples:
 254   //
 255   // (InstanceKlass C, initiating class loader ICL, Protection Domain PD)
 256   //
 257   // [Note that C.protection_domain(), which is stored in the java.lang.Class
 258   // mirror of C, is NOT the same as PD]
 259   //
 260   // If such an entry (C, ICL, PD) exists in the table, it means that
 261   // it is okay for a class Foo to reference C, where
 262   //
 263   //    Foo.protection_domain() == PD, and
 264   //    Foo's defining class loader == ICL
 265   //
 266   // The usage of the PD set can be seen in SystemDictionary::validate_protection_domain()
 267   // It is essentially a cache to avoid repeated Java up-calls to
 268   // ClassLoader.checkPackageAccess().
 269   //
 270   ProtectionDomainEntry* _pd_set;
 271   ClassLoaderData*       _loader_data;
 272 
 273  public:
 274   // Tells whether a protection is in the approved set.
 275   bool contains_protection_domain(oop protection_domain) const;
 276   // Adds a protection domain to the approved set.
 277   void add_protection_domain(Dictionary* dict, oop protection_domain);
 278 
 279   Klass* klass() const { return (Klass*)literal(); }
 280   Klass** klass_addr() { return (Klass**)literal_addr(); }
 281 
 282   DictionaryEntry* next() const {
 283     return (DictionaryEntry*)HashtableEntry<Klass*, mtClass>::next();
 284   }
 285 
 286   DictionaryEntry** next_addr() {
 287     return (DictionaryEntry**)HashtableEntry<Klass*, mtClass>::next_addr();
 288   }
 289 
 290   ClassLoaderData* loader_data() const { return _loader_data; }
 291   void set_loader_data(ClassLoaderData* loader_data) { _loader_data = loader_data; }
 292 
 293   ProtectionDomainEntry* pd_set() const { return _pd_set; }
 294   void set_pd_set(ProtectionDomainEntry* pd_set) { _pd_set = pd_set; }
 295 
 296   bool has_protection_domain() { return _pd_set != NULL; }
 297 
 298   // Tells whether the initiating class' protection can access the this _klass
 299   bool is_valid_protection_domain(Handle protection_domain) {
 300     if (!ProtectionDomainVerification) return true;
 301     if (!SystemDictionary::has_checkPackageAccess()) return true;
 302 
 303     return protection_domain() == NULL
 304          ? true
 305          : contains_protection_domain(protection_domain());
 306   }
 307 
 308   void set_strongly_reachable() {
 309     for (ProtectionDomainEntry* current = _pd_set;
 310                                 current != NULL;
 311                                 current = current->_next) {
 312       current->_pd_cache->set_strongly_reachable();
 313     }
 314   }
 315 
 316   void verify_protection_domain_set() {
 317     for (ProtectionDomainEntry* current = _pd_set;
 318                                 current != NULL;
 319                                 current = current->_next) {
 320       current->_pd_cache->protection_domain()->verify();
 321     }
 322   }
 323 
 324   bool equals(Symbol* class_name, ClassLoaderData* loader_data) const {
 325     Klass* klass = (Klass*)literal();
 326     return (InstanceKlass::cast(klass)->name()->equals(class_name) &&
 327             _loader_data == loader_data);
 328   }
 329 
 330   void print() {
 331     int count = 0;
 332     for (ProtectionDomainEntry* current = _pd_set;
 333                                 current != NULL;
 334                                 current = current->_next) {
 335       count++;
 336     }
 337     tty->print_cr("pd set = #%d", count);
 338   }
 339 };
 340 
 341 // Entry in a SymbolPropertyTable, mapping a single Symbol*
 342 // to a managed and an unmanaged pointer.
 343 class SymbolPropertyEntry : public HashtableEntry<Symbol*, mtSymbol> {
 344   friend class VMStructs;
 345  private:
 346   intptr_t _symbol_mode;  // secondary key
 347   Method*   _method;
 348   oop       _method_type;
 349 
 350  public:
 351   Symbol* symbol() const          { return literal(); }
 352 
 353   intptr_t symbol_mode() const      { return _symbol_mode; }
 354   void set_symbol_mode(intptr_t m)  { _symbol_mode = m; }
 355 
 356   Method*        method() const     { return _method; }
 357   void set_method(Method* p)        { _method = p; }
 358 
 359   oop      method_type() const      { return _method_type; }
 360   oop*     method_type_addr()       { return &_method_type; }
 361   void set_method_type(oop p)       { _method_type = p; }
 362 
 363   SymbolPropertyEntry* next() const {
 364     return (SymbolPropertyEntry*)HashtableEntry<Symbol*, mtSymbol>::next();
 365   }
 366 
 367   SymbolPropertyEntry** next_addr() {
 368     return (SymbolPropertyEntry**)HashtableEntry<Symbol*, mtSymbol>::next_addr();
 369   }
 370 
 371   void print_on(outputStream* st) const {
 372     symbol()->print_value_on(st);
 373     st->print("/mode="INTX_FORMAT, symbol_mode());
 374     st->print(" -> ");
 375     bool printed = false;
 376     if (method() != NULL) {
 377       method()->print_value_on(st);
 378       printed = true;
 379     }
 380     if (method_type() != NULL) {
 381       if (printed)  st->print(" and ");
 382       st->print(INTPTR_FORMAT, p2i((void *)method_type()));
 383       printed = true;
 384     }
 385     st->print_cr(printed ? "" : "(empty)");
 386   }
 387 };
 388 
 389 // A system-internal mapping of symbols to pointers, both managed
 390 // and unmanaged.  Used to record the auto-generation of each method
 391 // MethodHandle.invoke(S)T, for all signatures (S)T.
 392 class SymbolPropertyTable : public Hashtable<Symbol*, mtSymbol> {
 393   friend class VMStructs;
 394 private:
 395   SymbolPropertyEntry* bucket(int i) {
 396     return (SymbolPropertyEntry*) Hashtable<Symbol*, mtSymbol>::bucket(i);
 397   }
 398 
 399   // The following method is not MT-safe and must be done under lock.
 400   SymbolPropertyEntry** bucket_addr(int i) {
 401     return (SymbolPropertyEntry**) Hashtable<Symbol*, mtSymbol>::bucket_addr(i);
 402   }
 403 
 404   void add_entry(int index, SymbolPropertyEntry* new_entry) {
 405     ShouldNotReachHere();
 406   }
 407   void set_entry(int index, SymbolPropertyEntry* new_entry) {
 408     ShouldNotReachHere();
 409   }
 410 
 411   SymbolPropertyEntry* new_entry(unsigned int hash, Symbol* symbol, intptr_t symbol_mode) {
 412     SymbolPropertyEntry* entry = (SymbolPropertyEntry*) Hashtable<Symbol*, mtSymbol>::new_entry(hash, symbol);
 413     // Hashtable with Symbol* literal must increment and decrement refcount.
 414     symbol->increment_refcount();
 415     entry->set_symbol_mode(symbol_mode);
 416     entry->set_method(NULL);
 417     entry->set_method_type(NULL);
 418     return entry;
 419   }
 420 
 421 public:
 422   SymbolPropertyTable(int table_size);
 423   SymbolPropertyTable(int table_size, HashtableBucket<mtSymbol>* t, int number_of_entries);
 424 
 425   void free_entry(SymbolPropertyEntry* entry) {
 426     // decrement Symbol refcount here because hashtable doesn't.
 427     entry->literal()->decrement_refcount();
 428     Hashtable<Symbol*, mtSymbol>::free_entry(entry);
 429   }
 430 
 431   unsigned int compute_hash(Symbol* sym, intptr_t symbol_mode) {
 432     // Use the regular identity_hash.
 433     return Hashtable<Symbol*, mtSymbol>::compute_hash(sym) ^ symbol_mode;
 434   }
 435 
 436   int index_for(Symbol* name, intptr_t symbol_mode) {
 437     return hash_to_index(compute_hash(name, symbol_mode));
 438   }
 439 
 440   // need not be locked; no state change
 441   SymbolPropertyEntry* find_entry(int index, unsigned int hash, Symbol* name, intptr_t name_mode);
 442 
 443   // must be done under SystemDictionary_lock
 444   SymbolPropertyEntry* add_entry(int index, unsigned int hash, Symbol* name, intptr_t name_mode);
 445 
 446   // GC support
 447   void oops_do(OopClosure* f);
 448 
 449   void methods_do(void f(Method*));
 450 
 451   // Sharing support
 452   void reorder_dictionary();
 453 
 454 #ifndef PRODUCT
 455   void print();
 456 #endif
 457   void verify();
 458 };
 459 #endif // SHARE_VM_CLASSFILE_DICTIONARY_HPP