view src/share/vm/runtime/fieldType.hpp @ 1145:e018e6884bd8

6631166: CMS: better heuristics when combatting fragmentation Summary: Autonomic per-worker free block cache sizing, tunable coalition policies, fixes to per-size block statistics, retuned gain and bandwidth of some feedback loop filters to allow quicker reactivity to abrupt changes in ambient demand, and other heuristics to reduce fragmentation of the CMS old gen. Also tightened some assertions, including those related to locking. Reviewed-by: jmasa
author ysr
date Wed, 23 Dec 2009 09:23:54 -0800
parents a61af66fc99e
children c18cbe5936b8
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/*
 * Copyright 1997-2002 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 */

// Note: FieldType should be based on the SignatureIterator (or vice versa).
//       In any case, this structure should be re-thought at some point.

// A FieldType is used to determine the type of a field from a signature string.

class FieldType: public AllStatic {
 private:
  static void skip_optional_size(symbolOop signature, int* index);
  static bool is_valid_array_signature(symbolOop signature);
 public:

  // Return basic type
  static BasicType basic_type(symbolOop signature);

  // Testing
  static bool is_array(symbolOop signature) { return signature->utf8_length() > 1 && signature->byte_at(0) == '[' && is_valid_array_signature(signature); }

  static bool is_obj(symbolOop signature) {
     int sig_length = signature->utf8_length();
     // Must start with 'L' and end with ';'
     return (sig_length >= 2 &&
             (signature->byte_at(0) == 'L') &&
             (signature->byte_at(sig_length - 1) == ';'));
  }

  // Parse field and extract array information. Works for T_ARRAY only.
  static BasicType get_array_info(symbolOop signature, jint* dimension, symbolOop *object_key, TRAPS);
};