view src/share/vm/ci/ciArray.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) 1999, 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
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 */

#ifndef SHARE_VM_CI_CIARRAY_HPP
#define SHARE_VM_CI_CIARRAY_HPP

#include "ci/ciArrayKlass.hpp"
#include "ci/ciConstant.hpp"
#include "ci/ciObject.hpp"
#include "oops/arrayOop.hpp"
#include "oops/objArrayOop.hpp"
#include "oops/typeArrayOop.hpp"

// ciArray
//
// This class represents an arrayOop in the HotSpot virtual
// machine.
class ciArray : public ciObject {
private:
  int _length;

protected:
  ciArray(    arrayHandle h_a) : ciObject(h_a), _length(h_a()->length()) {}
  ciArray( objArrayHandle h_a) : ciObject(h_a), _length(h_a()->length()) {}
  ciArray(typeArrayHandle h_a) : ciObject(h_a), _length(h_a()->length()) {}

  ciArray(ciKlass* klass, int len) : ciObject(klass), _length(len) {}

  arrayOop get_arrayOop() const { return (arrayOop)get_oop(); }

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

  void print_impl(outputStream* st);

  ciConstant element_value_impl(BasicType elembt, arrayOop ary, int index);

public:
  int length() { return _length; }

  // Convenience routines.
  ciArrayKlass* array_type()         { return klass()->as_array_klass(); }
  ciType*       element_type()       { return array_type()->element_type(); }
  BasicType     element_basic_type() { return element_type()->basic_type(); }

  // Current value of an element.
  // Returns T_ILLEGAL if there is no element at the given index.
  ciConstant element_value(int index);

  // Current value of an element at the specified offset.
  // Returns T_ILLEGAL if there is no element at the given offset.
  ciConstant element_value_by_offset(intptr_t element_offset);

  // What kind of ciObject is this?
  bool is_array()        { return true; }
  bool is_java_object()  { return true; }
};

#endif // SHARE_VM_CI_CIARRAY_HPP