/*

 * Copyright (c) 2003, 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 "interpreter/interpreter.hpp"

#include "memory/gcLocker.hpp"

#include "memory/metadataFactory.hpp"

#include "oops/constMethod.hpp"

#include "oops/method.hpp"

// Static initialization

const u2 ConstMethod::MAX_IDNUM   = 0xFFFE;

const u2 ConstMethod::UNSET_IDNUM = 0xFFFF;

ConstMethod* ConstMethod::allocate(ClassLoaderData* loader_data,

  int size = ConstMethod::size(byte_code_size,

                                      compressed_line_number_size,

                                      localvariable_table_length,

                                      exception_table_length,

                                      checked_exceptions_length);

  return new (loader_data, size, true, THREAD) ConstMethod(

}

ConstMethod::ConstMethod(int byte_code_size,

  No_Safepoint_Verifier no_safepoint;

  set_interpreter_kind(Interpreter::invalid);

  init_fingerprint();

  set_constants(NULL);

  set_stackmap_data(NULL);

  set_code_size(byte_code_size);

  set_constMethod_size(size);

  set_inlined_tables_length(checked_exceptions_length,

                            compressed_line_number_size,

                            localvariable_table_length,

                            exception_table_length);

  assert(this->size() == size, "wrong size for object");

}

// Deallocate metadata fields associated with ConstMethod*

void ConstMethod::deallocate_contents(ClassLoaderData* loader_data) {

  set_interpreter_kind(Interpreter::invalid);

  if (stackmap_data() != NULL) {

    MetadataFactory::free_array<u1>(loader_data, stackmap_data());

  }

  set_stackmap_data(NULL);

}

// How big must this constMethodObject be?

int ConstMethod::size(int code_size,

                                    int compressed_line_number_size,

                                    int local_variable_table_length,

                                    int exception_table_length,

                                    int checked_exceptions_length) {

  int extra_bytes = code_size;

  if (compressed_line_number_size > 0) {

    extra_bytes += compressed_line_number_size;

  }

  if (checked_exceptions_length > 0) {

    extra_bytes += sizeof(u2);

    extra_bytes += checked_exceptions_length * sizeof(CheckedExceptionElement);

  }

  if (local_variable_table_length > 0) {

    extra_bytes += sizeof(u2);

    extra_bytes +=

              local_variable_table_length * sizeof(LocalVariableTableElement);

  }

  if (exception_table_length > 0) {

    extra_bytes += sizeof(u2);

    extra_bytes += exception_table_length * sizeof(ExceptionTableElement);

  }

  int extra_words = align_size_up(extra_bytes, BytesPerWord) / BytesPerWord;

  return align_object_size(header_size() + extra_words);

}

Method* ConstMethod::method() const {

    return InstanceKlass::cast(_constants->pool_holder())->method_with_idnum(

                               _method_idnum);

  }

// linenumber table - note that length is unknown until decompression,

// see class CompressedLineNumberReadStream.

u_char* ConstMethod::compressed_linenumber_table() const {

  // Located immediately following the bytecodes.

  assert(has_linenumber_table(), "called only if table is present");

  return code_end();

}

u2* ConstMethod::checked_exceptions_length_addr() const {

  // Located at the end of the constMethod.

  assert(has_checked_exceptions(), "called only if table is present");

  return last_u2_element();

}

u2* ConstMethod::exception_table_length_addr() const {

  assert(has_exception_handler(), "called only if table is present");

  if (has_checked_exceptions()) {

    // If checked_exception present, locate immediately before them.

    return (u2*) checked_exceptions_start() - 1;

  } else {

    // Else, the exception table is at the end of the constMethod.

    return last_u2_element();

  }

}

u2* ConstMethod::localvariable_table_length_addr() const {

  assert(has_localvariable_table(), "called only if table is present");

  if (has_exception_handler()) {

    // If exception_table present, locate immediately before them.

    return (u2*) exception_table_start() - 1;

  } else {

    if (has_checked_exceptions()) {

      // If checked_exception present, locate immediately before them.

      return (u2*) checked_exceptions_start() - 1;

    } else {

      // Else, the linenumber table is at the end of the constMethod.

      return last_u2_element();

    }

  }

}

// Update the flags to indicate the presence of these optional fields.

void ConstMethod::set_inlined_tables_length(

                                              int checked_exceptions_len,

                                              int compressed_line_number_size,

                                              int localvariable_table_len,

                                              int exception_table_len) {

  // Must be done in the order below, otherwise length_addr accessors

  // will not work. Only set bit in header if length is positive.

  assert(_flags == 0, "Error");

  if (compressed_line_number_size > 0) {

    _flags |= _has_linenumber_table;

  }

  if (checked_exceptions_len > 0) {

    _flags |= _has_checked_exceptions;

    *(checked_exceptions_length_addr()) = checked_exceptions_len;

  }

  if (exception_table_len > 0) {

    _flags |= _has_exception_table;

    *(exception_table_length_addr()) = exception_table_len;

  }

  if (localvariable_table_len > 0) {

    _flags |= _has_localvariable_table;

    *(localvariable_table_length_addr()) = localvariable_table_len;

  }

}

int ConstMethod::checked_exceptions_length() const {

  return has_checked_exceptions() ? *(checked_exceptions_length_addr()) : 0;

}

CheckedExceptionElement* ConstMethod::checked_exceptions_start() const {

  u2* addr = checked_exceptions_length_addr();

  u2 length = *addr;

  assert(length > 0, "should only be called if table is present");

  addr -= length * sizeof(CheckedExceptionElement) / sizeof(u2);

  return (CheckedExceptionElement*) addr;

}

int ConstMethod::localvariable_table_length() const {

  return has_localvariable_table() ? *(localvariable_table_length_addr()) : 0;

}

LocalVariableTableElement* ConstMethod::localvariable_table_start() const {

  u2* addr = localvariable_table_length_addr();

  u2 length = *addr;

  assert(length > 0, "should only be called if table is present");

  addr -= length * sizeof(LocalVariableTableElement) / sizeof(u2);

  return (LocalVariableTableElement*) addr;

}

int ConstMethod::exception_table_length() const {

  return has_exception_handler() ? *(exception_table_length_addr()) : 0;

}

ExceptionTableElement* ConstMethod::exception_table_start() const {

  u2* addr = exception_table_length_addr();

  u2 length = *addr;

  assert(length > 0, "should only be called if table is present");

  addr -= length * sizeof(ExceptionTableElement) / sizeof(u2);

  return (ExceptionTableElement*)addr;

}

// Printing

void ConstMethod::print_on(outputStream* st) const {

  ResourceMark rm;

  assert(is_constMethod(), "must be constMethod");

  st->print_cr(internal_name());

  st->print(" - method:       " INTPTR_FORMAT " ", (address)method());

  method()->print_value_on(st); st->cr();

  if (has_stackmap_table()) {

    st->print(" - stackmap data:       ");

    stackmap_data()->print_value_on(st);

    st->cr();

  }

}

// Short version of printing ConstMethod* - just print the name of the

// method it belongs to.

void ConstMethod::print_value_on(outputStream* st) const {

  assert(is_constMethod(), "must be constMethod");

  st->print(" const part of method " );

  method()->print_value_on(st);

}

// Verification

void ConstMethod::verify_on(outputStream* st) {

  guarantee(is_constMethod(), "object must be constMethod");

  guarantee(is_metadata(), err_msg("Should be metadata " PTR_FORMAT, this));

  // Verification can occur during oop construction before the method or

  // other fields have been initialized.

  guarantee(is_metadata(), err_msg("Should be metadata " PTR_FORMAT, this));

  guarantee(method()->is_method(), "should be method");

  address m_end = (address)((oop*) this + size());

  address compressed_table_start = code_end();

  guarantee(compressed_table_start <= m_end, "invalid method layout");

  address compressed_table_end = compressed_table_start;

  // Verify line number table

  if (has_linenumber_table()) {

    CompressedLineNumberReadStream stream(compressed_linenumber_table());

    while (stream.read_pair()) {

      guarantee(stream.bci() >= 0 && stream.bci() <= code_size(), "invalid bci in line number table");

    }

    compressed_table_end += stream.position();

  }

  guarantee(compressed_table_end <= m_end, "invalid method layout");

  // Verify checked exceptions, exception table and local variable tables

  if (has_checked_exceptions()) {

    u2* addr = checked_exceptions_length_addr();

    guarantee(*addr > 0 && (address) addr >= compressed_table_end && (address) addr < m_end, "invalid method layout");

  }

  if (has_exception_handler()) {

    u2* addr = exception_table_length_addr();

     guarantee(*addr > 0 && (address) addr >= compressed_table_end && (address) addr < m_end, "invalid method layout");

  }

  if (has_localvariable_table()) {

    u2* addr = localvariable_table_length_addr();

    guarantee(*addr > 0 && (address) addr >= compressed_table_end && (address) addr < m_end, "invalid method layout");

  }

  // Check compressed_table_end relative to uncompressed_table_start

  u2* uncompressed_table_start;

  if (has_localvariable_table()) {

    uncompressed_table_start = (u2*) localvariable_table_start();

  } else if (has_exception_handler()) {

    uncompressed_table_start = (u2*) exception_table_start();

  } else if (has_checked_exceptions()) {

      uncompressed_table_start = (u2*) checked_exceptions_start();

  } else {

      uncompressed_table_start = (u2*) m_end;

  }

  int gap = (intptr_t) uncompressed_table_start - (intptr_t) compressed_table_end;

  int max_gap = align_object_size(1)*BytesPerWord;

  guarantee(gap >= 0 && gap < max_gap, "invalid method layout");

}