view src/share/vm/ci/ciObjArrayKlass.cpp @ 9126:bc26f978b0ce

HotSpotResolvedObjectType: implement hasFinalizeSubclass() correctly don't use the (wrong) cached value, but ask the runtime on each request. Fixes regression on xml.* benchmarks @ specjvm2008. The problem was: After the constructor of Object was deoptimized due to an assumption violation, it was recompiled again after some time. However, on recompilation, the value of hasFinalizeSubclass for the class was not updated and it was compiled again with a, now wrong, assumption, which then triggers deoptimization again. This was repeated until it hit the recompilation limit (defined by PerMethodRecompilationCutoff), and therefore only executed by the interpreter from now on, causing the performance regression.
author Bernhard Urban <bernhard.urban@jku.at>
date Mon, 15 Apr 2013 19:54:58 +0200
parents d8ce2825b193
children d13d7aba8c12
line wrap: on
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/*
 * Copyright (c) 1999, 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.
 *
 */

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

// ciObjArrayKlass
//
// This class represents a Klass* 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");
  Klass* element_Klass = get_ObjArrayKlass()->bottom_klass();
  _base_element_klass = CURRENT_ENV->get_klass(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;
  }
  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, T_OBJECT) {
    _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;
      Klass* element_Klass = get_ObjArrayKlass()->element_klass();
      _element_klass = CURRENT_THREAD_ENV->get_klass(element_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,
                          constantPoolHandle(),
                          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();

  Symbol* base_name_sym = element_name->get_symbol();
  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
    Klass* 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_obj_array_klass(array);
  }

  // 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) {
  GUARDED_VM_ENTRY(return make_impl(element_klass);)
}