1 /*
   2  * Copyright (c) 2005, 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
  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                                      constantPoolHandle pool, int cp_index, Symbol* error)
  36 {
  37   assert_locked_or_safepoint(SystemDictionary_lock);
  38   assert(!pool.is_null() && error != NULL, "adding NULL obj");
  39 
  40   ResolutionErrorEntry* entry = new_entry(hash, pool(), cp_index, error);
  41   add_entry(index, entry);
  42 }
  43 
  44 // find entry in the table
  45 ResolutionErrorEntry* ResolutionErrorTable::find_entry(int index, unsigned int hash,
  46                                                        constantPoolHandle pool, int cp_index)
  47 {
  48   assert_locked_or_safepoint(SystemDictionary_lock);
  49 
  50   for (ResolutionErrorEntry *error_probe = bucket(index);
  51                          error_probe != NULL;
  52                          error_probe = error_probe->next()) {
  53   if (error_probe->hash() == hash && error_probe->pool() == pool()) {
  54       return error_probe;;
  55     }
  56   }
  57   return NULL;
  58 }
  59 
  60 void ResolutionErrorEntry::set_error(Symbol* e) {
  61   assert(e == NULL || _error == NULL, "cannot reset error");
  62   _error = e;
  63   if (_error != NULL) _error->increment_refcount();
  64 }
  65 
  66 // create new error entry
  67 ResolutionErrorEntry* ResolutionErrorTable::new_entry(int hash, ConstantPool* pool,
  68                                                       int cp_index, Symbol* error)
  69 {
  70   ResolutionErrorEntry* entry = (ResolutionErrorEntry*)Hashtable<ConstantPool*, mtClass>::new_entry(hash, pool);
  71   entry->set_cp_index(cp_index);
  72   NOT_PRODUCT(entry->set_error(NULL);)
  73   entry->set_error(error);
  74 
  75   return entry;
  76 }
  77 
  78 void ResolutionErrorTable::free_entry(ResolutionErrorEntry *entry) {
  79   // decrement error refcount
  80   assert(entry->error() != NULL, "error should be set");
  81   entry->error()->decrement_refcount();
  82   Hashtable<ConstantPool*, mtClass>::free_entry(entry);
  83 }
  84 
  85 
  86 // create resolution error table
  87 ResolutionErrorTable::ResolutionErrorTable(int table_size)
  88     : Hashtable<ConstantPool*, mtClass>(table_size, sizeof(ResolutionErrorEntry)) {
  89 }
  90 
  91 // RedefineClasses support - remove matching entry of a
  92 // constant pool that is going away
  93 void ResolutionErrorTable::delete_entry(ConstantPool* c) {
  94   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
  95   for (int i = 0; i < table_size(); i++) {
  96     for (ResolutionErrorEntry** p = bucket_addr(i); *p != NULL; ) {
  97       ResolutionErrorEntry* entry = *p;
  98       assert(entry->pool() != NULL, "resolution error table is corrupt");
  99       if (entry->pool() == c) {
 100         *p = entry->next();
 101         free_entry(entry);
 102       } else {
 103         p = entry->next_addr();
 104       }
 105     }
 106   }
 107 }
 108 
 109 
 110 // Remove unloaded entries from the table
 111 void ResolutionErrorTable::purge_resolution_errors() {
 112   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
 113   for (int i = 0; i < table_size(); i++) {
 114     for (ResolutionErrorEntry** p = bucket_addr(i); *p != NULL; ) {
 115       ResolutionErrorEntry* entry = *p;
 116       assert(entry->pool() != (ConstantPool*)NULL, "resolution error table is corrupt");
 117       ConstantPool* pool = entry->pool();
 118       assert(pool->pool_holder() != NULL, "Constant pool without a class?");
 119       ClassLoaderData* loader_data =
 120               pool->pool_holder()->class_loader_data();
 121       if (!loader_data->is_unloading()) {
 122         p = entry->next_addr();
 123       } else {
 124         *p = entry->next();
 125         free_entry(entry);
 126       }
 127     }
 128   }
 129 }