1 /*
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   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.
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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).
  14  *
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
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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/protectionDomainCache.hpp"
  29 #include "classfile/systemDictionary.hpp"
  30 #include "oops/instanceKlass.hpp"
  31 #include "oops/oop.hpp"
  32 #include "runtime/orderAccess.hpp"
  33 #include "utilities/hashtable.hpp"
  34 #include "utilities/ostream.hpp"
  35 
  36 class DictionaryEntry;
  37 class BoolObjectClosure;
  38 
  39 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  40 // The data structure for the class loader data dictionaries (and the shared system
  41 // dictionary).
  42 
  43 class Dictionary : public Hashtable<InstanceKlass*, mtClass> {
  44   friend class VMStructs;
  45 
  46   static bool _some_dictionary_needs_resizing;
  47   bool _resizable;
  48   bool _needs_resizing;
  49   void check_if_needs_resize();
  50 
  51   ClassLoaderData* _loader_data;  // backpointer to owning loader
  52   ClassLoaderData* loader_data() const { return _loader_data; }
  53 
  54   DictionaryEntry* get_entry(int index, unsigned int hash, Symbol* name);
  55 
  56 protected:
  57   static size_t entry_size();
  58 public:
  59   Dictionary(ClassLoaderData* loader_data, int table_size, bool resizable = false);
  60   Dictionary(ClassLoaderData* loader_data, int table_size, HashtableBucket<mtClass>* t, int number_of_entries, bool resizable = false);
  61   ~Dictionary();
  62 
  63   static bool does_any_dictionary_needs_resizing();
  64   bool resize_if_needed();
  65 
  66   DictionaryEntry* new_entry(unsigned int hash, InstanceKlass* klass);
  67 
  68   void add_klass(unsigned int hash, Symbol* class_name, InstanceKlass* obj);
  69 
  70   InstanceKlass* find_class(int index, unsigned int hash, Symbol* name);
  71 
  72   InstanceKlass* find_shared_class(int index, unsigned int hash, Symbol* name);
  73 
  74   // GC support
  75   void oops_do(OopClosure* f);
  76   void roots_oops_do(OopClosure* strong, OopClosure* weak);
  77 
  78   void classes_do(void f(InstanceKlass*));
  79   void classes_do(void f(InstanceKlass*, TRAPS), TRAPS);
  80   void all_entries_do(void f(InstanceKlass*, ClassLoaderData*));
  81   void classes_do(MetaspaceClosure* it);
  82 
  83   void unlink(BoolObjectClosure* is_alive);
  84   void remove_classes_in_error_state();
  85 
  86   // Unload classes whose defining loaders are unloaded
  87   void do_unloading();
  88 
  89   // Protection domains
  90   InstanceKlass* find(unsigned int hash, Symbol* name, Handle protection_domain);
  91   bool is_valid_protection_domain(unsigned int hash,
  92                                   Symbol* name,
  93                                   Handle protection_domain);
  94   void add_protection_domain(int index, unsigned int hash,
  95                              InstanceKlass* klass,
  96                              Handle protection_domain, TRAPS);
  97 
  98   // Sharing support
  99   void reorder_dictionary_for_sharing();
 100 
 101   void print_on(outputStream* st) const;
 102   void verify();
 103   DictionaryEntry* bucket(int i) const {
 104     return (DictionaryEntry*)Hashtable<InstanceKlass*, mtClass>::bucket(i);
 105   }
 106 
 107   // The following method is not MT-safe and must be done under lock.
 108   DictionaryEntry** bucket_addr(int i) {
 109     return (DictionaryEntry**)Hashtable<InstanceKlass*, mtClass>::bucket_addr(i);
 110   }
 111 
 112   void add_entry(int index, DictionaryEntry* new_entry) {
 113     Hashtable<InstanceKlass*, mtClass>::add_entry(index, (HashtableEntry<InstanceKlass*, mtClass>*)new_entry);
 114   }
 115 
 116   void unlink_entry(DictionaryEntry* entry) {
 117     Hashtable<InstanceKlass*, mtClass>::unlink_entry((HashtableEntry<InstanceKlass*, mtClass>*)entry);
 118   }
 119 
 120   void free_entry(DictionaryEntry* entry);
 121 };
 122 
 123 // An entry in the class loader data dictionaries, this describes a class as
 124 // { InstanceKlass*, protection_domain }.
 125 
 126 class DictionaryEntry : public HashtableEntry<InstanceKlass*, mtClass> {
 127   friend class VMStructs;
 128  private:
 129   // Contains the set of approved protection domains that can access
 130   // this dictionary entry.
 131   //
 132   // This protection domain set is a set of tuples:
 133   //
 134   // (InstanceKlass C, initiating class loader ICL, Protection Domain PD)
 135   //
 136   // [Note that C.protection_domain(), which is stored in the java.lang.Class
 137   // mirror of C, is NOT the same as PD]
 138   //
 139   // If such an entry (C, ICL, PD) exists in the table, it means that
 140   // it is okay for a class Foo to reference C, where
 141   //
 142   //    Foo.protection_domain() == PD, and
 143   //    Foo's defining class loader == ICL
 144   //
 145   // The usage of the PD set can be seen in SystemDictionary::validate_protection_domain()
 146   // It is essentially a cache to avoid repeated Java up-calls to
 147   // ClassLoader.checkPackageAccess().
 148   //
 149   ProtectionDomainEntry* volatile _pd_set;
 150 
 151  public:
 152   // Tells whether a protection is in the approved set.
 153   bool contains_protection_domain(oop protection_domain) const;
 154   // Adds a protection domain to the approved set.
 155   void add_protection_domain(Dictionary* dict, Handle protection_domain);
 156 
 157   InstanceKlass* instance_klass() const { return literal(); }
 158   InstanceKlass** klass_addr() { return (InstanceKlass**)literal_addr(); }
 159 
 160   DictionaryEntry* next() const {
 161     return (DictionaryEntry*)HashtableEntry<InstanceKlass*, mtClass>::next();
 162   }
 163 
 164   DictionaryEntry** next_addr() {
 165     return (DictionaryEntry**)HashtableEntry<InstanceKlass*, mtClass>::next_addr();
 166   }
 167 
 168   ProtectionDomainEntry* pd_set() const            { return _pd_set; }
 169   void set_pd_set(ProtectionDomainEntry* new_head) {  _pd_set = new_head; }
 170 
 171   ProtectionDomainEntry* pd_set_acquire() const    {
 172     return OrderAccess::load_acquire(&_pd_set);
 173   }
 174   void release_set_pd_set(ProtectionDomainEntry* new_head) {
 175     OrderAccess::release_store(&_pd_set, new_head);
 176   }
 177 
 178   // Tells whether the initiating class' protection domain can access the klass in this entry
 179   bool is_valid_protection_domain(Handle protection_domain) {
 180     if (!ProtectionDomainVerification) return true;
 181     if (!SystemDictionary::has_checkPackageAccess()) return true;
 182 
 183     return protection_domain() == NULL
 184          ? true
 185          : contains_protection_domain(protection_domain());
 186   }
 187 
 188   void verify_protection_domain_set() {
 189     for (ProtectionDomainEntry* current = pd_set(); // accessed at a safepoint
 190                                 current != NULL;
 191                                 current = current->_next) {
 192       current->_pd_cache->protection_domain()->verify();
 193     }
 194   }
 195 
 196   bool equals(const Symbol* class_name) const {
 197     InstanceKlass* klass = (InstanceKlass*)literal();
 198     return (klass->name() == class_name);
 199   }
 200 
 201   void print_count(outputStream *st) {
 202     int count = 0;
 203     for (ProtectionDomainEntry* current = pd_set();  // accessed inside SD lock
 204                                 current != NULL;
 205                                 current = current->_next) {
 206       count++;
 207     }
 208     st->print_cr("pd set count = #%d", count);
 209   }
 210 
 211   void verify();
 212 };
 213 
 214 // Entry in a SymbolPropertyTable, mapping a single Symbol*
 215 // to a managed and an unmanaged pointer.
 216 class SymbolPropertyEntry : public HashtableEntry<Symbol*, mtSymbol> {
 217   friend class VMStructs;
 218  private:
 219   intptr_t _symbol_mode;  // secondary key
 220   Method*   _method;
 221   oop       _method_type;
 222 
 223  public:
 224   Symbol* symbol() const            { return literal(); }
 225 
 226   intptr_t symbol_mode() const      { return _symbol_mode; }
 227   void set_symbol_mode(intptr_t m)  { _symbol_mode = m; }
 228 
 229   Method*        method() const     { return _method; }
 230   void set_method(Method* p)        { _method = p; }
 231 
 232   oop      method_type() const      { return _method_type; }
 233   oop*     method_type_addr()       { return &_method_type; }
 234   void set_method_type(oop p)       { _method_type = p; }
 235 
 236   SymbolPropertyEntry* next() const {
 237     return (SymbolPropertyEntry*)HashtableEntry<Symbol*, mtSymbol>::next();
 238   }
 239 
 240   SymbolPropertyEntry** next_addr() {
 241     return (SymbolPropertyEntry**)HashtableEntry<Symbol*, mtSymbol>::next_addr();
 242   }
 243 
 244   void print_entry(outputStream* st) const {
 245     symbol()->print_value_on(st);
 246     st->print("/mode=" INTX_FORMAT, symbol_mode());
 247     st->print(" -> ");
 248     bool printed = false;
 249     if (method() != NULL) {
 250       method()->print_value_on(st);
 251       printed = true;
 252     }
 253     if (method_type() != NULL) {
 254       if (printed)  st->print(" and ");
 255       st->print(INTPTR_FORMAT, p2i((void *)method_type()));
 256       printed = true;
 257     }
 258     st->print_cr(printed ? "" : "(empty)");
 259   }
 260 };
 261 
 262 // A system-internal mapping of symbols to pointers, both managed
 263 // and unmanaged.  Used to record the auto-generation of each method
 264 // MethodHandle.invoke(S)T, for all signatures (S)T.
 265 class SymbolPropertyTable : public Hashtable<Symbol*, mtSymbol> {
 266   friend class VMStructs;
 267 private:
 268   // The following method is not MT-safe and must be done under lock.
 269   SymbolPropertyEntry** bucket_addr(int i) {
 270     return (SymbolPropertyEntry**) Hashtable<Symbol*, mtSymbol>::bucket_addr(i);
 271   }
 272 
 273   void add_entry(int index, SymbolPropertyEntry* new_entry) {
 274     ShouldNotReachHere();
 275   }
 276   void set_entry(int index, SymbolPropertyEntry* new_entry) {
 277     ShouldNotReachHere();
 278   }
 279 
 280   SymbolPropertyEntry* new_entry(unsigned int hash, Symbol* symbol, intptr_t symbol_mode) {
 281     SymbolPropertyEntry* entry = (SymbolPropertyEntry*) Hashtable<Symbol*, mtSymbol>::new_entry(hash, symbol);
 282     // Hashtable with Symbol* literal must increment and decrement refcount.
 283     symbol->increment_refcount();
 284     entry->set_symbol_mode(symbol_mode);
 285     entry->set_method(NULL);
 286     entry->set_method_type(NULL);
 287     return entry;
 288   }
 289 
 290 public:
 291   SymbolPropertyTable(int table_size);
 292   SymbolPropertyTable(int table_size, HashtableBucket<mtSymbol>* t, int number_of_entries);
 293 
 294   void free_entry(SymbolPropertyEntry* entry) {
 295     // decrement Symbol refcount here because hashtable doesn't.
 296     entry->literal()->decrement_refcount();
 297     Hashtable<Symbol*, mtSymbol>::free_entry(entry);
 298   }
 299 
 300   unsigned int compute_hash(Symbol* sym, intptr_t symbol_mode) {
 301     // Use the regular identity_hash.
 302     return Hashtable<Symbol*, mtSymbol>::compute_hash(sym) ^ symbol_mode;
 303   }
 304 
 305   int index_for(Symbol* name, intptr_t symbol_mode) {
 306     return hash_to_index(compute_hash(name, symbol_mode));
 307   }
 308 
 309   // need not be locked; no state change
 310   SymbolPropertyEntry* find_entry(int index, unsigned int hash, Symbol* name, intptr_t name_mode);
 311 
 312   // must be done under SystemDictionary_lock
 313   SymbolPropertyEntry* add_entry(int index, unsigned int hash, Symbol* name, intptr_t name_mode);
 314 
 315   // GC support
 316   void oops_do(OopClosure* f);
 317 
 318   void methods_do(void f(Method*));
 319 
 320   void verify();
 321 
 322   SymbolPropertyEntry* bucket(int i) {
 323     return (SymbolPropertyEntry*) Hashtable<Symbol*, mtSymbol>::bucket(i);
 324   }
 325 };
 326 #endif // SHARE_VM_CLASSFILE_DICTIONARY_HPP
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