view src/share/vm/ci/ciObjArrayKlass.cpp @ 2149:7e37af9d69ef

7011379: G1: overly long concurrent marking cycles Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads. Reviewed-by: johnc, ysr
author tonyp
date Wed, 19 Jan 2011 09:35:17 -0500
parents f95d63e2154a
children 3582bf76420e
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/*
 * Copyright (c) 1999, 2010, 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.
 *
 */

#include "precompiled.hpp"
#include "ci/ciInstanceKlass.hpp"
#include "ci/ciObjArrayKlass.hpp"
#include "ci/ciObjArrayKlassKlass.hpp"
#include "ci/ciSymbol.hpp"
#include "ci/ciUtilities.hpp"
#include "oops/objArrayKlass.hpp"

// ciObjArrayKlass
//
// This class represents a klassOop in the HotSpot virtual machine
// whose Klass part is an objArrayKlass.

// ------------------------------------------------------------------
// ciObjArrayKlass::ciObjArrayKlass
//
// Constructor for loaded object array klasses.
ciObjArrayKlass::ciObjArrayKlass(KlassHandle h_k) : ciArrayKlass(h_k) {
  assert(get_Klass()->oop_is_objArray(), "wrong type");
  klassOop element_klassOop = get_objArrayKlass()->bottom_klass();
  _base_element_klass = CURRENT_ENV->get_object(element_klassOop)->as_klass();
  assert(_base_element_klass->is_instance_klass() ||
         _base_element_klass->is_type_array_klass(), "bad base klass");
  if (dimension() == 1) {
    _element_klass = _base_element_klass;
  } else {
    _element_klass = NULL;
  }
  if (!ciObjectFactory::is_initialized()) {
    assert(_element_klass->is_java_lang_Object(), "only arrays of object are shared");
  }
}

// ------------------------------------------------------------------
// ciObjArrayKlass::ciObjArrayKlass
//
// Constructor for unloaded object array klasses.
ciObjArrayKlass::ciObjArrayKlass(ciSymbol* array_name,
                                 ciKlass* base_element_klass,
                                 int dimension)
  : ciArrayKlass(array_name,
                 dimension,
                 ciObjArrayKlassKlass::make()) {
    _base_element_klass = base_element_klass;
    assert(_base_element_klass->is_instance_klass() ||
           _base_element_klass->is_type_array_klass(), "bad base klass");
    if (dimension == 1) {
      _element_klass = base_element_klass;
    } else {
      _element_klass = NULL;
    }
}

// ------------------------------------------------------------------
// ciObjArrayKlass::element_klass
//
// What is the one-level element type of this array?
ciKlass* ciObjArrayKlass::element_klass() {
  if (_element_klass == NULL) {
    assert(dimension() > 1, "_element_klass should not be NULL");
    // Produce the element klass.
    if (is_loaded()) {
      VM_ENTRY_MARK;
      klassOop element_klassOop = get_objArrayKlass()->element_klass();
      _element_klass = CURRENT_THREAD_ENV->get_object(element_klassOop)->as_klass();
    } else {
      VM_ENTRY_MARK;
      // We are an unloaded array klass.  Attempt to fetch our
      // element klass by name.
      _element_klass = CURRENT_THREAD_ENV->get_klass_by_name_impl(
                          this,
                          construct_array_name(base_element_klass()->name(),
                                               dimension() - 1),
                          false);
    }
  }
  return _element_klass;
}

// ------------------------------------------------------------------
// ciObjArrayKlass::construct_array_name
//
// Build an array name from an element name and a dimension.
ciSymbol* ciObjArrayKlass::construct_array_name(ciSymbol* element_name,
                                                int dimension) {
  EXCEPTION_CONTEXT;
  int element_len = element_name->utf8_length();

  symbolOop base_name_sym = element_name->get_symbolOop();
  char* name;

  if (base_name_sym->byte_at(0) == '[' ||
      (base_name_sym->byte_at(0) == 'L' &&  // watch package name 'Lxx'
       base_name_sym->byte_at(element_len-1) == ';')) {

    int new_len = element_len + dimension + 1; // for the ['s and '\0'
    name = CURRENT_THREAD_ENV->name_buffer(new_len);

    int pos = 0;
    for ( ; pos < dimension; pos++) {
      name[pos] = '[';
    }
    strncpy(name+pos, (char*)element_name->base(), element_len);
    name[new_len-1] = '\0';
  } else {
    int new_len =   3                       // for L, ;, and '\0'
                  + dimension               // for ['s
                  + element_len;

    name = CURRENT_THREAD_ENV->name_buffer(new_len);
    int pos = 0;
    for ( ; pos < dimension; pos++) {
      name[pos] = '[';
    }
    name[pos++] = 'L';
    strncpy(name+pos, (char*)element_name->base(), element_len);
    name[new_len-2] = ';';
    name[new_len-1] = '\0';
  }
  return ciSymbol::make(name);
}

// ------------------------------------------------------------------
// ciObjArrayKlass::make_impl
//
// Implementation of make.
ciObjArrayKlass* ciObjArrayKlass::make_impl(ciKlass* element_klass) {

  if (element_klass->is_loaded()) {
    EXCEPTION_CONTEXT;
    // The element klass is loaded
    klassOop array = element_klass->get_Klass()->array_klass(THREAD);
    if (HAS_PENDING_EXCEPTION) {
      CLEAR_PENDING_EXCEPTION;
      CURRENT_THREAD_ENV->record_out_of_memory_failure();
      return ciEnv::unloaded_ciobjarrayklass();
    }
    return CURRENT_THREAD_ENV->get_object(array)->as_obj_array_klass();
  }

  // The array klass was unable to be made or the element klass was
  // not loaded.
  ciSymbol* array_name = construct_array_name(element_klass->name(), 1);
  if (array_name == ciEnv::unloaded_cisymbol()) {
    return ciEnv::unloaded_ciobjarrayklass();
  }
  return
    CURRENT_ENV->get_unloaded_klass(element_klass, array_name)
                        ->as_obj_array_klass();
}

// ------------------------------------------------------------------
// ciObjArrayKlass::make
//
// Make an array klass corresponding to the specified primitive type.
ciObjArrayKlass* ciObjArrayKlass::make(ciKlass* element_klass) {
  assert(element_klass->is_java_klass(), "wrong kind of klass");
  GUARDED_VM_ENTRY(return make_impl(element_klass);)
}