1 /*
   2  * Copyright (c) 2005, 2010, 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, symbolHandle error)
  36 {
  37   assert_locked_or_safepoint(SystemDictionary_lock);
  38   assert(!pool.is_null() && !error.is_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 // create new error entry
  61 ResolutionErrorEntry* ResolutionErrorTable::new_entry(int hash, constantPoolOop pool,
  62                                                       int cp_index, symbolOop error)
  63 {
  64   ResolutionErrorEntry* entry = (ResolutionErrorEntry*)Hashtable::new_entry(hash, pool);
  65   entry->set_cp_index(cp_index);
  66   entry->set_error(error);
  67 
  68   return entry;
  69 }
  70 
  71 // create resolution error table
  72 ResolutionErrorTable::ResolutionErrorTable(int table_size)
  73     : Hashtable(table_size, sizeof(ResolutionErrorEntry)) {
  74 }
  75 
  76 // GC support
  77 void ResolutionErrorTable::oops_do(OopClosure* f) {
  78   for (int i = 0; i < table_size(); i++) {
  79     for (ResolutionErrorEntry* probe = bucket(i);
  80                            probe != NULL;
  81                            probe = probe->next()) {
  82       assert(probe->pool() != (constantPoolOop)NULL, "resolution error table is corrupt");
  83       assert(probe->error() != (symbolOop)NULL, "resolution error table is corrupt");
  84       probe->oops_do(f);
  85     }
  86   }
  87 }
  88 
  89 // GC support
  90 void ResolutionErrorEntry::oops_do(OopClosure* blk) {
  91   blk->do_oop((oop*)pool_addr());
  92   blk->do_oop((oop*)error_addr());
  93 }
  94 
  95 // We must keep the symbolOop used in the error alive. The constantPoolOop will
  96 // decide when the entry can be purged.
  97 void ResolutionErrorTable::always_strong_classes_do(OopClosure* blk) {
  98   for (int i = 0; i < table_size(); i++) {
  99     for (ResolutionErrorEntry* probe = bucket(i);
 100                            probe != NULL;
 101                            probe = probe->next()) {
 102       assert(probe->error() != (symbolOop)NULL, "resolution error table is corrupt");
 103       blk->do_oop((oop*)probe->error_addr());
 104     }
 105   }
 106 }
 107 
 108 // Remove unloaded entries from the table
 109 void ResolutionErrorTable::purge_resolution_errors(BoolObjectClosure* is_alive) {
 110   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
 111   for (int i = 0; i < table_size(); i++) {
 112     for (ResolutionErrorEntry** p = bucket_addr(i); *p != NULL; ) {
 113       ResolutionErrorEntry* entry = *p;
 114       assert(entry->pool() != (constantPoolOop)NULL, "resolution error table is corrupt");
 115       constantPoolOop pool = entry->pool();
 116       if (is_alive->do_object_b(pool)) {
 117         p = entry->next_addr();
 118       } else {
 119         *p = entry->next();
 120         free_entry(entry);
 121       }
 122     }
 123   }
 124 }