jdk8-mips64-public/hotspot: src/share/vm/utilities/resourceHash.hpp@59c790074993 (annotated)

src/share/vm/utilities/resourceHash.hpp@59c790074993 (annotated)

src/share/vm/utilities/resourceHash.hpp

Wed, 28 Nov 2012 17:50:21 -0500

author: coleenp
date: Wed, 28 Nov 2012 17:50:21 -0500
changeset 4295: 59c790074993
parent 4245: 4735d2c84362
child 6461: bdd155477289
permissions: -rw-r--r--

8003635: NPG: AsynchGetCallTrace broken by Method* virtual call
Summary: Make metaspace::contains be lock free and used to see if something is in metaspace, also compare Method* with vtbl pointer.
Reviewed-by: dholmes, sspitsyn, dcubed, jmasa

 /*
  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #ifndef SHARE_VM_UTILITIES_RESOURCEHASH_HPP
 #define SHARE_VM_UTILITIES_RESOURCEHASH_HPP
 #include "memory/allocation.hpp"
 #include "utilities/top.hpp"
 template<typename K> struct ResourceHashtableFns {
     typedef unsigned (*hash_fn)(K const&);
     typedef bool (*equals_fn)(K const&, K const&);
 };
 template<typename K> unsigned primitive_hash(const K& k) {
   unsigned hash = (unsigned)((uintptr_t)k);
   return hash ^ (hash > 3); // just in case we're dealing with aligned ptrs
 }
 template<typename K> bool primitive_equals(const K& k0, const K& k1) {
   return k0 == k1;
 }
 template<
     typename K, typename V,
     typename ResourceHashtableFns<K>::hash_fn   HASH   = primitive_hash<K>,
     typename ResourceHashtableFns<K>::equals_fn EQUALS = primitive_equals<K>,
     unsigned SIZE = 256
     >
 class ResourceHashtable : public ResourceObj {
  private:
   class Node : public ResourceObj {
    public:
     unsigned _hash;
     K _key;
     V _value;
     Node* _next;
     Node(unsigned hash, K const& key, V const& value) :
         _hash(hash), _key(key), _value(value), _next(NULL) {}
   };
   Node* _table[SIZE];
   // Returns a pointer to where the node where the value would reside if
   // it's in the table.
   Node** lookup_node(unsigned hash, K const& key) {
     unsigned index = hash % SIZE;
     Node** ptr = &_table[index];
     while (*ptr != NULL) {
       Node* node = *ptr;
       if (node->_hash == hash && EQUALS(key, node->_key)) {
         break;
       }
       ptr = &(node->_next);
     }
     return ptr;
   }
   Node const** lookup_node(unsigned hash, K const& key) const {
     return const_cast<Node const**>(
         const_cast<ResourceHashtable*>(this)->lookup_node(hash, key));
   }
  public:
   ResourceHashtable() { memset(_table, 0, SIZE * sizeof(Node*)); }
   bool contains(K const& key) const {
     return get(key) != NULL;
   }
   V* get(K const& key) const {
     unsigned hv = HASH(key);
     Node const** ptr = lookup_node(hv, key);
     if (*ptr != NULL) {
       return const_cast<V*>(&(*ptr)->_value);
     } else {
       return NULL;
     }
   }
   // Inserts or replaces a value in the table
   void put(K const& key, V const& value) {
     unsigned hv = HASH(key);
     Node** ptr = lookup_node(hv, key);
     if (*ptr != NULL) {
       (*ptr)->_value = value;
     } else {
       *ptr = new Node(hv, key, value);
     }
   }
   // ITER contains bool do_entry(K const&, V const&), which will be
   // called for each entry in the table.  If do_entry() returns false,
   // the iteration is cancelled.
   template<class ITER>
   void iterate(ITER* iter) const {
     Node* const* bucket = _table;
     while (bucket < &_table[SIZE]) {
       Node* node = *bucket;
       while (node != NULL) {
         bool cont = iter->do_entry(node->_key, node->_value);
         if (!cont) { return; }
         node = node->_next;
       }
       ++bucket;
     }
   }
 };
 #endif // SHARE_VM_UTILITIES_RESOURCEHASH_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/utilities/resourceHash.hpp@59c790074993 (annotated)

src/share/vm/utilities/resourceHash.hpp