1 /*
   2  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "oops/constMethodOop.hpp"
  27 #include "oops/methodOop.hpp"
  28 
  29 // Static initialization
  30 const u2 constMethodOopDesc::MAX_IDNUM   = 0xFFFE;
  31 const u2 constMethodOopDesc::UNSET_IDNUM = 0xFFFF;
  32 
  33 // How big must this constMethodObject be?
  34 
  35 int constMethodOopDesc::object_size(int code_size,
  36                                     int compressed_line_number_size,
  37                                     int local_variable_table_length,
  38                                     int checked_exceptions_length) {
  39   int extra_bytes = code_size;
  40   if (compressed_line_number_size > 0) {
  41     extra_bytes += compressed_line_number_size;
  42   }
  43   if (checked_exceptions_length > 0) {
  44     extra_bytes += sizeof(u2);
  45     extra_bytes += checked_exceptions_length * sizeof(CheckedExceptionElement);
  46   }
  47   if (local_variable_table_length > 0) {
  48     extra_bytes += sizeof(u2);
  49     extra_bytes +=
  50               local_variable_table_length * sizeof(LocalVariableTableElement);
  51   }
  52   int extra_words = align_size_up(extra_bytes, BytesPerWord) / BytesPerWord;
  53   return align_object_size(header_size() + extra_words);
  54 }
  55 
  56 
  57 // linenumber table - note that length is unknown until decompression,
  58 // see class CompressedLineNumberReadStream.
  59 
  60 u_char* constMethodOopDesc::compressed_linenumber_table() const {
  61   // Located immediately following the bytecodes.
  62   assert(has_linenumber_table(), "called only if table is present");
  63   return code_end();
  64 }
  65 
  66 u2* constMethodOopDesc::checked_exceptions_length_addr() const {
  67   // Located at the end of the constMethod.
  68   assert(has_checked_exceptions(), "called only if table is present");
  69   return last_u2_element();
  70 }
  71 
  72 u2* constMethodOopDesc::localvariable_table_length_addr() const {
  73   assert(has_localvariable_table(), "called only if table is present");
  74   if (has_checked_exceptions()) {
  75     // If checked_exception present, locate immediately before them.
  76     return (u2*) checked_exceptions_start() - 1;
  77   } else {
  78     // Else, the linenumber table is at the end of the constMethod.
  79     return last_u2_element();
  80   }
  81 }
  82 
  83 
  84 // Update the flags to indicate the presence of these optional fields.
  85 void constMethodOopDesc::set_inlined_tables_length(
  86                                               int checked_exceptions_len,
  87                                               int compressed_line_number_size,
  88                                               int localvariable_table_len) {
  89   // Must be done in the order below, otherwise length_addr accessors
  90   // will not work. Only set bit in header if length is positive.
  91   assert(_flags == 0, "Error");
  92   if (compressed_line_number_size > 0) {
  93     _flags |= _has_linenumber_table;
  94   }
  95   if (checked_exceptions_len > 0) {
  96     _flags |= _has_checked_exceptions;
  97     *(checked_exceptions_length_addr()) = checked_exceptions_len;
  98   }
  99   if (localvariable_table_len > 0) {
 100     _flags |= _has_localvariable_table;
 101     *(localvariable_table_length_addr()) = localvariable_table_len;
 102   }
 103 }
 104 
 105 
 106 int constMethodOopDesc::checked_exceptions_length() const {
 107   return has_checked_exceptions() ? *(checked_exceptions_length_addr()) : 0;
 108 }
 109 
 110 
 111 CheckedExceptionElement* constMethodOopDesc::checked_exceptions_start() const {
 112   u2* addr = checked_exceptions_length_addr();
 113   u2 length = *addr;
 114   assert(length > 0, "should only be called if table is present");
 115   addr -= length * sizeof(CheckedExceptionElement) / sizeof(u2);
 116   return (CheckedExceptionElement*) addr;
 117 }
 118 
 119 
 120 int constMethodOopDesc::localvariable_table_length() const {
 121   return has_localvariable_table() ? *(localvariable_table_length_addr()) : 0;
 122 }
 123 
 124 
 125 LocalVariableTableElement* constMethodOopDesc::localvariable_table_start() const {
 126   u2* addr = localvariable_table_length_addr();
 127   u2 length = *addr;
 128   assert(length > 0, "should only be called if table is present");
 129   addr -= length * sizeof(LocalVariableTableElement) / sizeof(u2);
 130   return (LocalVariableTableElement*) addr;
 131 }