       1 /*
       2  * Copyright (c) 2003, 2014, 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_DICTIONARY_HPP
      26 #define SHARE_VM_CLASSFILE_DICTIONARY_HPP
      27
      28 #include "classfile/systemDictionary.hpp"
      29 #include "oops/instanceKlass.hpp"
      30 #include "oops/oop.inline.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() == 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