/*
 * Copyright (c) 2016, 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
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 *
 */

#include "ci/ciField.hpp"
#include "ci/ciValueKlass.hpp"
#include "oops/valueKlass.hpp"

// Number of value type factory parameters
int ciValueKlass::param_count() const {
  valueKlassHandle vklass_h(ValueKlass::cast(get_Klass()));
  methodHandle factory_h(vklass_h->factory_method());
  return factory_h->constMethod()->valuefactory_parameter_mapping_length();
}

// Size of value type factory parameters in words
int ciValueKlass::param_size() {
  int size = 0;
  for (int i = 0; i < param_count(); ++i) {
    size += get_field_type_by_index(i)->size();
  }
  return size;
}

// Returns the value factory parameter index of the field with the given offset.
// If the field at 'offset' belongs to a flattened value type field, return the
// index of the ValueType parameter corresponding to this flattened value type.
int ciValueKlass::get_field_index_by_offset(int offset) {
  assert(contains_field_offset(offset), "invalid field offset");
  int best_offset = 0;
  int best_index = -1;
  // Search the field with the given offset
  for (int i = 0; i < param_count(); ++i) {
    int field_offset = get_field_offset_by_index(i);
    if (field_offset == offset) {
      // Exact match
      return i;
    } else if (field_offset < offset && field_offset > best_offset) {
      // No exact match. Save the index of the field with the closest offset that
      // is smaller than the given field offset. This index corresponds to the
      // flattened value type field that holds the field we are looking for.
      best_offset = field_offset;
      best_index = i;
    }
  }
  assert(best_index >= 0, "field not found");
  assert(best_offset == offset || get_field_type_by_index(best_index)->is_valuetype(), "offset should match for non-VTs");
  return best_index;
}

// Returns the field offset of the value factory parameter with the given index
int ciValueKlass::get_field_offset_by_index(int index) const {
  // Compute the field index from the factory parameter index
  valueKlassHandle vklass_h(ValueKlass::cast(get_Klass()));
  methodHandle factory_h(vklass_h->factory_method());
  int field_index = factory_h->constMethod()->valuefactory_parameter_mapping_start()[index].data.field_index;
  // Get the field offset
  return vklass_h->field_offset(field_index);
}

// Returns the field type of the value factory parameter with the given index
ciType* ciValueKlass::get_field_type_by_index(int index) {
  int offset = get_field_offset_by_index(index);
  VM_ENTRY_MARK;
  return get_field_type_by_offset(offset);
}

// Offset of the first field in the value type
int ciValueKlass::get_first_field_offset() const {
  valueKlassHandle vklass_h(ValueKlass::cast(get_Klass()));
  return vklass_h()->first_field_offset();
}