1 /*
   2  * Copyright (c) 2003, 2012, 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 methodOop constMethodOopDesc::method() const {
  57     return instanceKlass::cast(_constants->pool_holder())->method_with_idnum(
  58                                _method_idnum);
  59   }
  60 
  61 // linenumber table - note that length is unknown until decompression,
  62 // see class CompressedLineNumberReadStream.
  63 
  64 u_char* constMethodOopDesc::compressed_linenumber_table() const {
  65   // Located immediately following the bytecodes.
  66   assert(has_linenumber_table(), "called only if table is present");
  67   return code_end();
  68 }
  69 
  70 u2* constMethodOopDesc::checked_exceptions_length_addr() const {
  71   // Located at the end of the constMethod.
  72   assert(has_checked_exceptions(), "called only if table is present");
  73   return last_u2_element();
  74 }
  75 
  76 u2* constMethodOopDesc::localvariable_table_length_addr() const {
  77   assert(has_localvariable_table(), "called only if table is present");
  78   if (has_checked_exceptions()) {
  79     // If checked_exception present, locate immediately before them.
  80     return (u2*) checked_exceptions_start() - 1;
  81   } else {
  82     // Else, the linenumber table is at the end of the constMethod.
  83     return last_u2_element();
  84   }
  85 }
  86 
  87 
  88 // Update the flags to indicate the presence of these optional fields.
  89 void constMethodOopDesc::set_inlined_tables_length(
  90                                               int checked_exceptions_len,
  91                                               int compressed_line_number_size,
  92                                               int localvariable_table_len) {
  93   // Must be done in the order below, otherwise length_addr accessors
  94   // will not work. Only set bit in header if length is positive.
  95   assert(_flags == 0, "Error");
  96   if (compressed_line_number_size > 0) {
  97     _flags |= _has_linenumber_table;
  98   }
  99   if (checked_exceptions_len > 0) {
 100     _flags |= _has_checked_exceptions;
 101     *(checked_exceptions_length_addr()) = checked_exceptions_len;
 102   }
 103   if (localvariable_table_len > 0) {
 104     _flags |= _has_localvariable_table;
 105     *(localvariable_table_length_addr()) = localvariable_table_len;
 106   }
 107 }
 108 
 109 
 110 int constMethodOopDesc::checked_exceptions_length() const {
 111   return has_checked_exceptions() ? *(checked_exceptions_length_addr()) : 0;
 112 }
 113 
 114 
 115 CheckedExceptionElement* constMethodOopDesc::checked_exceptions_start() const {
 116   u2* addr = checked_exceptions_length_addr();
 117   u2 length = *addr;
 118   assert(length > 0, "should only be called if table is present");
 119   addr -= length * sizeof(CheckedExceptionElement) / sizeof(u2);
 120   return (CheckedExceptionElement*) addr;
 121 }
 122 
 123 
 124 int constMethodOopDesc::localvariable_table_length() const {
 125   return has_localvariable_table() ? *(localvariable_table_length_addr()) : 0;
 126 }
 127 
 128 
 129 LocalVariableTableElement* constMethodOopDesc::localvariable_table_start() const {
 130   u2* addr = localvariable_table_length_addr();
 131   u2 length = *addr;
 132   assert(length > 0, "should only be called if table is present");
 133   addr -= length * sizeof(LocalVariableTableElement) / sizeof(u2);
 134   return (LocalVariableTableElement*) addr;
 135 }