1 /*
   2  * Copyright (c) 2003, 2012, 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
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  23  */
  24 
  25 #ifndef SHARE_VM_CLASSFILE_LOADERCONSTRAINTS_HPP
  26 #define SHARE_VM_CLASSFILE_LOADERCONSTRAINTS_HPP
  27 
  28 #include "classfile/dictionary.hpp"
  29 #include "classfile/placeholders.hpp"
  30 #include "utilities/hashtable.hpp"
  31 
  32 class LoaderConstraintEntry;
  33 class Symbol;
  34 
  35 class LoaderConstraintTable : public Hashtable<Klass*, mtClass> {
  36   friend class VMStructs;
  37 private:
  38 
  39   enum Constants {
  40     _loader_constraint_size = 107,                     // number of entries in constraint table
  41     _nof_buckets            = 1009                     // number of buckets in hash table
  42   };
  43 
  44   LoaderConstraintEntry** find_loader_constraint(Symbol* name,
  45                                                  Handle loader);
  46 
  47 public:
  48 
  49   LoaderConstraintTable(int nof_buckets);
  50 
  51   LoaderConstraintEntry* new_entry(unsigned int hash, Symbol* name,
  52                                    Klass* klass, int num_loaders,
  53                                    int max_loaders);
  54   void free_entry(LoaderConstraintEntry *entry);
  55 
  56   LoaderConstraintEntry* bucket(int i) {
  57     return (LoaderConstraintEntry*)Hashtable<Klass*, mtClass>::bucket(i);
  58   }
  59 
  60   LoaderConstraintEntry** bucket_addr(int i) {
  61     return (LoaderConstraintEntry**)Hashtable<Klass*, mtClass>::bucket_addr(i);
  62   }
  63 
  64   // Check class loader constraints
  65   bool add_entry(Symbol* name, Klass* klass1, Handle loader1,
  66                                     Klass* klass2, Handle loader2);
  67 
  68   // Note:  The main entry point for this module is via SystemDictionary.
  69   // SystemDictionary::check_signature_loaders(Symbol* signature,
  70   //                                           Handle loader1, Handle loader2,
  71   //                                           bool is_method, TRAPS)
  72 
  73   Klass* find_constrained_klass(Symbol* name, Handle loader);
  74 
  75   // Class loader constraints
  76 
  77   void ensure_loader_constraint_capacity(LoaderConstraintEntry *p, int nfree);
  78   void extend_loader_constraint(LoaderConstraintEntry* p, Handle loader,
  79                                 Klass* klass);
  80   void merge_loader_constraints(LoaderConstraintEntry** pp1,
  81                                 LoaderConstraintEntry** pp2, Klass* klass);
  82 
  83   bool check_or_update(instanceKlassHandle k, Handle loader,
  84                               Symbol* name);
  85 
  86 
  87   void purge_loader_constraints();
  88 
  89   void verify(Dictionary* dictionary, PlaceholderTable* placeholders);
  90 #ifndef PRODUCT
  91   void print();
  92 #endif
  93 };
  94 
  95 class LoaderConstraintEntry : public HashtableEntry<Klass*, mtClass> {
  96   friend class VMStructs;
  97 private:
  98   Symbol*                _name;                   // class name
  99   int                    _num_loaders;
 100   int                    _max_loaders;
 101   // Loader constraints enforce correct linking behavior.
 102   // Thus, it really operates on ClassLoaderData which represents linking domain,
 103   // not class loaders.
 104   ClassLoaderData**              _loaders;                // initiating loaders
 105 
 106 public:
 107 
 108   Klass* klass() { return literal(); }
 109   Klass** klass_addr() { return literal_addr(); }
 110   void set_klass(Klass* k) { set_literal(k); }
 111 
 112   LoaderConstraintEntry* next() {
 113     return (LoaderConstraintEntry*)HashtableEntry<Klass*, mtClass>::next();
 114   }
 115 
 116   LoaderConstraintEntry** next_addr() {
 117     return (LoaderConstraintEntry**)HashtableEntry<Klass*, mtClass>::next_addr();
 118   }
 119   void set_next(LoaderConstraintEntry* next) {
 120     HashtableEntry<Klass*, mtClass>::set_next(next);
 121   }
 122 
 123   Symbol* name() { return _name; }
 124   void set_name(Symbol* name) {
 125     _name = name;
 126     if (name != NULL) name->increment_refcount();
 127   }
 128 
 129   int num_loaders() { return _num_loaders; }
 130   void set_num_loaders(int i) { _num_loaders = i; }
 131 
 132   int max_loaders() { return _max_loaders; }
 133   void set_max_loaders(int i) { _max_loaders = i; }
 134 
 135   ClassLoaderData** loaders() { return _loaders; }
 136   void set_loaders(ClassLoaderData** loaders) { _loaders = loaders; }
 137 
 138   ClassLoaderData* loader_data(int i) { return _loaders[i]; }
 139   void set_loader_data(int i, ClassLoaderData* p) { _loaders[i] = p; }
 140   // convenience
 141   void set_loader(int i, oop p);
 142 };
 143 
 144 #endif // SHARE_VM_CLASSFILE_LOADERCONSTRAINTS_HPP