gold/defstd.cc

   1 // defstd.cc -- define standard symbols for gold.
   2
   3 // Copyright (C) 2006-2019 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include "symtab.h"
  26 #include "layout.h"
  27 #include "defstd.h"
  28
  29 // This is a simple file which defines the standard symbols like
  30 // "_end".
  31
  32 namespace
  33 {
  34
  35 using namespace gold;
  36
  37 const Define_symbol_in_section in_section[] =
  38 {
  39   {
  40     "__preinit_array_start",    // name
  41     ".preinit_array",           // output_section
  42     0,                          // value
  43     0,                          // size
  44     elfcpp::STT_NOTYPE,         // type
  45     elfcpp::STB_GLOBAL,         // binding
  46     elfcpp::STV_HIDDEN,         // visibility
  47     0,                          // nonvis
  48     false,                      // offset_is_from_end
  49     true                        // only_if_ref
  50   },
  51   {
  52     "__preinit_array_end",      // name
  53     ".preinit_array",           // output_section
  54     0,                          // value
  55     0,                          // size
  56     elfcpp::STT_NOTYPE,         // type
  57     elfcpp::STB_GLOBAL,         // binding
  58     elfcpp::STV_HIDDEN,         // visibility
  59     0,                          // nonvis
  60     true,                       // offset_is_from_end
  61     true                        // only_if_ref
  62   },
  63   {
  64     "__init_array_start",       // name
  65     ".init_array",              // output_section
  66     0,                          // value
  67     0,                          // size
  68     elfcpp::STT_NOTYPE,         // type
  69     elfcpp::STB_GLOBAL,         // binding
  70     elfcpp::STV_HIDDEN,         // visibility
  71     0,                          // nonvis
  72     false,                      // offset_is_from_end
  73     true                        // only_if_ref
  74   },
  75   {
  76     "__init_array_end",         // name
  77     ".init_array",              // output_section
  78     0,                          // value
  79     0,                          // size
  80     elfcpp::STT_NOTYPE,         // type
  81     elfcpp::STB_GLOBAL,         // binding
  82     elfcpp::STV_HIDDEN,         // visibility
  83     0,                          // nonvis
  84     true,                       // offset_is_from_end
  85     true                        // only_if_ref
  86   },
  87   {
  88     "__fini_array_start",       // name
  89     ".fini_array",              // output_section
  90     0,                          // value
  91     0,                          // size
  92     elfcpp::STT_NOTYPE,         // type
  93     elfcpp::STB_GLOBAL,         // binding
  94     elfcpp::STV_HIDDEN,         // visibility
  95     0,                          // nonvis
  96     false,                      // offset_is_from_end
  97     true                        // only_if_ref
  98   },
  99   {
 100     "__fini_array_end",         // name
 101     ".fini_array",              // output_section
 102     0,                          // value
 103     0,                          // size
 104     elfcpp::STT_NOTYPE,         // type
 105     elfcpp::STB_GLOBAL,         // binding
 106     elfcpp::STV_HIDDEN,         // visibility
 107     0,                          // nonvis
 108     true,                       // offset_is_from_end
 109     true                        // only_if_ref
 110   },
 111   {
 112     "__stack",                  // name
 113     ".stack",                   // output_section
 114     0,                          // value
 115     0,                          // size
 116     elfcpp::STT_NOTYPE,         // type
 117     elfcpp::STB_GLOBAL,         // binding
 118     elfcpp::STV_DEFAULT,        // visibility
 119     0,                          // nonvis
 120     false,                      // offset_is_from_end
 121     true                        // only_if_ref
 122   },
 123 };
 124
 125 const int in_section_count = sizeof in_section / sizeof in_section[0];
 126
 127 const Define_symbol_in_segment in_segment[] =
 128 {
 129   {
 130     "__executable_start",       // name
 131     elfcpp::PT_LOAD,            // segment_type
 132     elfcpp::PF(0),              // segment_flags_set
 133     elfcpp::PF(0),              // segment_flags_clear
 134     0,                          // value
 135     0,                          // size
 136     elfcpp::STT_NOTYPE,         // type
 137     elfcpp::STB_GLOBAL,         // binding
 138     elfcpp::STV_DEFAULT,        // visibility
 139     0,                          // nonvis
 140     Symbol::SEGMENT_START,      // offset_from_base
 141     true                        // only_if_ref
 142   },
 143   {
 144     "__ehdr_start",             // name
 145     elfcpp::PT_LOAD,            // segment_type
 146     elfcpp::PF(0),              // segment_flags_set
 147     elfcpp::PF(0),              // segment_flags_clear
 148     0,                          // value
 149     0,                          // size
 150     elfcpp::STT_NOTYPE,         // type
 151     elfcpp::STB_GLOBAL,         // binding
 152     elfcpp::STV_HIDDEN,         // visibility
 153     0,                          // nonvis
 154     Symbol::SEGMENT_START,      // offset_from_base
 155     true                        // only_if_ref
 156   },
 157   {
 158     "etext",                    // name
 159     elfcpp::PT_LOAD,            // segment_type
 160     elfcpp::PF_X,               // segment_flags_set
 161     elfcpp::PF_W,               // segment_flags_clear
 162     0,                          // value
 163     0,                          // size
 164     elfcpp::STT_NOTYPE,         // type
 165     elfcpp::STB_GLOBAL,         // binding
 166     elfcpp::STV_DEFAULT,        // visibility
 167     0,                          // nonvis
 168     Symbol::SEGMENT_END,        // offset_from_base
 169     true                        // only_if_ref
 170   },
 171   {
 172     "_etext",                   // name
 173     elfcpp::PT_LOAD,            // segment_type
 174     elfcpp::PF_X,               // segment_flags_set
 175     elfcpp::PF_W,               // segment_flags_clear
 176     0,                          // value
 177     0,                          // size
 178     elfcpp::STT_NOTYPE,         // type
 179     elfcpp::STB_GLOBAL,         // binding
 180     elfcpp::STV_DEFAULT,        // visibility
 181     0,                          // nonvis
 182     Symbol::SEGMENT_END,        // offset_from_base
 183     true                        // only_if_ref
 184   },
 185   {
 186     "__etext",                  // name
 187     elfcpp::PT_LOAD,            // segment_type
 188     elfcpp::PF_X,               // segment_flags_set
 189     elfcpp::PF_W,               // segment_flags_clear
 190     0,                          // value
 191     0,                          // size
 192     elfcpp::STT_NOTYPE,         // type
 193     elfcpp::STB_GLOBAL,         // binding
 194     elfcpp::STV_DEFAULT,        // visibility
 195     0,                          // nonvis
 196     Symbol::SEGMENT_END,        // offset_from_base
 197     true                        // only_if_ref
 198   },
 199   {
 200     "_edata",                   // name
 201     elfcpp::PT_LOAD,            // segment_type
 202     elfcpp::PF_W,               // segment_flags_set
 203     elfcpp::PF(0),              // segment_flags_clear
 204     0,                          // value
 205     0,                          // size
 206     elfcpp::STT_NOTYPE,         // type
 207     elfcpp::STB_GLOBAL,         // binding
 208     elfcpp::STV_DEFAULT,        // visibility
 209     0,                          // nonvis
 210     Symbol::SEGMENT_BSS,        // offset_from_base
 211     false                       // only_if_ref
 212   },
 213   {
 214     "edata",                    // name
 215     elfcpp::PT_LOAD,            // segment_type
 216     elfcpp::PF_W,               // segment_flags_set
 217     elfcpp::PF(0),              // segment_flags_clear
 218     0,                          // value
 219     0,                          // size
 220     elfcpp::STT_NOTYPE,         // type
 221     elfcpp::STB_GLOBAL,         // binding
 222     elfcpp::STV_DEFAULT,        // visibility
 223     0,                          // nonvis
 224     Symbol::SEGMENT_BSS,        // offset_from_base
 225     true                        // only_if_ref
 226   },
 227   {
 228     "__bss_start",              // name
 229     elfcpp::PT_LOAD,            // segment_type
 230     elfcpp::PF_W,               // segment_flags_set
 231     elfcpp::PF(0),              // segment_flags_clear
 232     0,                          // value
 233     0,                          // size
 234     elfcpp::STT_NOTYPE,         // type
 235     elfcpp::STB_GLOBAL,         // binding
 236     elfcpp::STV_DEFAULT,        // visibility
 237     0,                          // nonvis
 238     Symbol::SEGMENT_BSS,        // offset_from_base
 239     false                       // only_if_ref
 240   },
 241   {
 242     "_end",                     // name
 243     elfcpp::PT_LOAD,            // segment_type
 244     elfcpp::PF_W,               // segment_flags_set
 245     elfcpp::PF(0),              // segment_flags_clear
 246     0,                          // value
 247     0,                          // size
 248     elfcpp::STT_NOTYPE,         // type
 249     elfcpp::STB_GLOBAL,         // binding
 250     elfcpp::STV_DEFAULT,        // visibility
 251     0,                          // nonvis
 252     Symbol::SEGMENT_END,        // offset_from_base
 253     false                       // only_if_ref
 254   },
 255   {
 256     "end",                      // name
 257     elfcpp::PT_LOAD,            // segment_type
 258     elfcpp::PF_W,               // segment_flags_set
 259     elfcpp::PF(0),              // segment_flags_clear
 260     0,                          // value
 261     0,                          // size
 262     elfcpp::STT_NOTYPE,         // type
 263     elfcpp::STB_GLOBAL,         // binding
 264     elfcpp::STV_DEFAULT,        // visibility
 265     0,                          // nonvis
 266     Symbol::SEGMENT_END,        // offset_from_base
 267     true                        // only_if_ref
 268   }
 269 };
 270
 271 const int in_segment_count = sizeof in_segment / sizeof in_segment[0];
 272
 273 } // End anonymous namespace.
 274
 275 namespace gold
 276 {
 277
 278 void
 279 define_standard_symbols(Symbol_table* symtab, const Layout* layout)
 280 {
 281   bool saw_sections_clause = layout->script_options()->saw_sections_clause();
 282   symtab->define_symbols(layout, in_section_count, in_section,
 283                          saw_sections_clause);
 284   symtab->define_symbols(layout, in_segment_count, in_segment,
 285                          saw_sections_clause);
 286 }
 287
 288 } // End namespace gold.