1 /*
   2  * Copyright (c) 2005, 2018, 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 #include "precompiled.hpp"
  26 #include "classfile/resolutionErrors.hpp"
  27 #include "memory/resourceArea.hpp"
  28 #include "oops/oop.inline.hpp"
  29 #include "runtime/handles.inline.hpp"
  30 #include "runtime/safepoint.hpp"
  31 #include "utilities/hashtable.inline.hpp"
  32 
  33 // add new entry to the table
  34 void ResolutionErrorTable::add_entry(int index, unsigned int hash,
  35                                      const constantPoolHandle& pool, int cp_index,
  36                                      Symbol* error, Symbol* message)
  37 {
  38   assert_locked_or_safepoint(SystemDictionary_lock);
  39   assert(!pool.is_null() && error != NULL, "adding NULL obj");
  40 
  41   ResolutionErrorEntry* entry = new_entry(hash, pool(), cp_index, error, message);
  42   add_entry(index, entry);
  43 }
  44 
  45 // find entry in the table
  46 ResolutionErrorEntry* ResolutionErrorTable::find_entry(int index, unsigned int hash,
  47                                                        const constantPoolHandle& pool, int cp_index)
  48 {
  49   assert_locked_or_safepoint(SystemDictionary_lock);
  50 
  51   for (ResolutionErrorEntry *error_probe = bucket(index);
  52                          error_probe != NULL;
  53                          error_probe = error_probe->next()) {
  54   if (error_probe->hash() == hash && error_probe->pool() == pool()) {
  55       return error_probe;;
  56     }
  57   }
  58   return NULL;
  59 }
  60 
  61 void ResolutionErrorEntry::set_error(Symbol* e) {
  62   assert(e != NULL, "must set a value");
  63   _error = e;
  64   _error->increment_refcount();
  65 }
  66 
  67 void ResolutionErrorEntry::set_message(Symbol* c) {
  68   _message = c;
  69   if (_message != NULL) {
  70     _message->increment_refcount();
  71   }
  72 }
  73 
  74 // create new error entry
  75 ResolutionErrorEntry* ResolutionErrorTable::new_entry(int hash, ConstantPool* pool,
  76                                                       int cp_index, Symbol* error,
  77                                                       Symbol* message)
  78 {
  79   ResolutionErrorEntry* entry = (ResolutionErrorEntry*)Hashtable<ConstantPool*, mtClass>::new_entry(hash, pool);
  80   entry->set_cp_index(cp_index);
  81   entry->set_error(error);
  82   entry->set_message(message);
  83 
  84   return entry;
  85 }
  86 
  87 void ResolutionErrorTable::free_entry(ResolutionErrorEntry *entry) {
  88   // decrement error refcount
  89   assert(entry->error() != NULL, "error should be set");
  90   entry->error()->decrement_refcount();
  91   if (entry->message() != NULL) {
  92     entry->message()->decrement_refcount();
  93   }
  94   Hashtable<ConstantPool*, mtClass>::free_entry(entry);
  95 }
  96 
  97 
  98 // create resolution error table
  99 ResolutionErrorTable::ResolutionErrorTable(int table_size)
 100     : Hashtable<ConstantPool*, mtClass>(table_size, sizeof(ResolutionErrorEntry)) {
 101 }
 102 
 103 // RedefineClasses support - remove matching entry of a
 104 // constant pool that is going away
 105 void ResolutionErrorTable::delete_entry(ConstantPool* c) {
 106   assert_locked_or_safepoint(SystemDictionary_lock);
 107   for (int i = 0; i < table_size(); i++) {
 108     for (ResolutionErrorEntry** p = bucket_addr(i); *p != NULL; ) {
 109       ResolutionErrorEntry* entry = *p;
 110       assert(entry->pool() != NULL, "resolution error table is corrupt");
 111       if (entry->pool() == c) {
 112         *p = entry->next();
 113         free_entry(entry);
 114       } else {
 115         p = entry->next_addr();
 116       }
 117     }
 118   }
 119 }
 120 
 121 
 122 // Remove unloaded entries from the table
 123 void ResolutionErrorTable::purge_resolution_errors() {
 124   assert_locked_or_safepoint(SystemDictionary_lock);
 125   for (int i = 0; i < table_size(); i++) {
 126     for (ResolutionErrorEntry** p = bucket_addr(i); *p != NULL; ) {
 127       ResolutionErrorEntry* entry = *p;
 128       assert(entry->pool() != (ConstantPool*)NULL, "resolution error table is corrupt");
 129       ConstantPool* pool = entry->pool();
 130       assert(pool->pool_holder() != NULL, "Constant pool without a class?");
 131 
 132       if (pool->pool_holder()->is_loader_alive()) {
 133         p = entry->next_addr();
 134       } else {
 135         *p = entry->next();
 136         free_entry(entry);
 137       }
 138     }
 139   }
 140 }