view src/share/vm/ci/ciType.hpp @ 20543:e7d0505c8a30

8059758: Footprint regressions with JDK-8038423 Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything. Reviewed-by: jwilhelm, brutisso
author tschatzl
date Fri, 10 Oct 2014 15:51:58 +0200
parents 55fb97c4c58d
children 4ca6dc0799b6
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/*
 * Copyright (c) 2000, 2013, 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_CI_CITYPE_HPP
#define SHARE_VM_CI_CITYPE_HPP

#include "ci/ciMetadata.hpp"

// ciType
//
// This class represents either a class (T_OBJECT), array (T_ARRAY),
// or one of the primitive types such as T_INT.
class ciType : public ciMetadata {
  CI_PACKAGE_ACCESS
  friend class ciKlass;
  friend class ciReturnAddress;

private:
  BasicType _basic_type;

  ciType(BasicType t);     // for primitive and unloaded types
  ciType(KlassHandle k);   // for subclasses (reference types)

  const char* type_string() { return "ciType"; }

  void print_impl(outputStream* st);

  // Distinguished instances of primitive ciTypes..
  static ciType* _basic_types[T_CONFLICT+1];

public:
  BasicType basic_type() const              { return _basic_type; }

  // Returns true iff the types are identical, or if both are klasses
  // and the is_subtype_of relation holds between the klasses.
  bool is_subtype_of(ciType* type);

  // Get the instance of java.lang.Class corresponding to this type.
  // There are mirrors for instance, array, and primitive types (incl. void).
  virtual ciInstance*    java_mirror();

  // Get the class which "boxes" (or "wraps") values of this type.
  // Example:  short is boxed by java.lang.Short, etc.
  // Returns self if it is a reference type.
  // Returns NULL for void, since null is used in such cases.
  ciKlass*  box_klass();

  // Returns true if this is not a klass or array (i.e., not a reference type).
  bool is_primitive_type() const            { return basic_type() != T_OBJECT && basic_type() != T_ARRAY; }
  int size() const                          { return type2size[basic_type()]; }
  bool is_void() const                      { return basic_type() == T_VOID; }
  bool is_one_word() const                  { return size() == 1; }
  bool is_two_word() const                  { return size() == 2; }

  // What kind of ciObject is this?
  bool is_type() const                      { return true; }
  bool is_classless() const                 { return is_primitive_type(); }

  const char* name();
  virtual void print_name_on(outputStream* st);
  void print_name() {
    print_name_on(tty);
  }

  static ciType* make(BasicType t);
};


// ciReturnAddress
//
// This class represents the type of a specific return address in the
// bytecodes.
class ciReturnAddress : public ciType {
  CI_PACKAGE_ACCESS

private:
  // The bci of this return address.
  int _bci;

  ciReturnAddress(int bci);

  const char* type_string() { return "ciReturnAddress"; }

  void print_impl(outputStream* st);

public:
  bool is_return_address() const { return true; }

  int  bci() { return _bci; }

  static ciReturnAddress* make(int bci);
};

#endif // SHARE_VM_CI_CITYPE_HPP