gold/parameters.cc

   1 // parameters.cc -- general parameters for a link using gold
   2
   3 // Copyright (C) 2006-2020 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 "debug.h"
  26 #include "options.h"
  27 #include "target.h"
  28 #include "target-select.h"
  29
  30 namespace gold
  31 {
  32
  33 // Our local version of the variable, which is not const.
  34
  35 static Parameters static_parameters;
  36
  37 // The global variable.
  38
  39 const Parameters* parameters = &static_parameters;
  40
  41 // A helper class to set the target once.
  42
  43 class Set_parameters_target_once : public Once
  44 {
  45  public:
  46   Set_parameters_target_once(Parameters* parameters)
  47     : parameters_(parameters)
  48   { }
  49
  50  protected:
  51   void
  52   do_run_once(void* arg)
  53   { this->parameters_->set_target_once(static_cast<Target*>(arg)); }
  54
  55  private:
  56   Parameters* parameters_;
  57 };
  58
  59 // We only need one Set_parameters_target_once.
  60
  61 static
  62 Set_parameters_target_once set_parameters_target_once(&static_parameters);
  63
  64 // Class Parameters.
  65
  66 Parameters::Parameters()
  67    : errors_(NULL), timer_(NULL), options_(NULL), target_(NULL),
  68      doing_static_link_valid_(false), doing_static_link_(false),
  69      debug_(0), incremental_mode_(General_options::INCREMENTAL_OFF),
  70      set_parameters_target_once_(&set_parameters_target_once)
  71  {
  72  }
  73
  74 void
  75 Parameters::set_errors(Errors* errors)
  76 {
  77   gold_assert(this->errors_ == NULL);
  78   this->errors_ = errors;
  79 }
  80
  81 void
  82 Parameters::set_timer(Timer* timer)
  83 {
  84   gold_assert(this->timer_ == NULL);
  85   this->timer_ = timer;
  86 }
  87
  88 void
  89 Parameters::set_options(const General_options* options)
  90 {
  91   gold_assert(!this->options_valid());
  92   this->options_ = options;
  93   // For speed, we convert the options() debug var from a string to an
  94   // enum (from debug.h).
  95   this->debug_ = debug_string_to_enum(this->options().debug());
  96   // Set incremental_mode_ based on the value of the --incremental option.
  97   // We copy the mode into parameters because it can change based on inputs.
  98   this->incremental_mode_ = this->options().incremental_mode();
  99   // If --verbose is set, it acts as "--debug=files".
 100   if (options->verbose())
 101     this->debug_ |= DEBUG_FILES;
 102   if (this->target_valid())
 103     this->check_target_endianness();
 104 }
 105
 106 void
 107 Parameters::set_doing_static_link(bool doing_static_link)
 108 {
 109   gold_assert(!this->doing_static_link_valid_);
 110   this->doing_static_link_ = doing_static_link;
 111   this->doing_static_link_valid_ = true;
 112 }
 113
 114 void
 115 Parameters::set_target(Target* target)
 116 {
 117   this->set_parameters_target_once_->run_once(static_cast<void*>(target));
 118   gold_assert(target == this->target_);
 119 }
 120
 121 // This is called at most once.
 122
 123 void
 124 Parameters::set_target_once(Target* target)
 125 {
 126   gold_assert(this->target_ == NULL);
 127   this->target_ = target;
 128   target->select_as_default_target();
 129   if (this->options_valid())
 130     {
 131       this->check_target_endianness();
 132       this->check_rodata_segment();
 133     }
 134 }
 135
 136 // Clear the target, for testing.
 137
 138 void
 139 Parameters::clear_target()
 140 {
 141   this->target_ = NULL;
 142   // We need a new Set_parameters_target_once so that we can set the
 143   // target again.
 144   this->set_parameters_target_once_ = new Set_parameters_target_once(this);
 145 }
 146
 147 // Return whether TARGET is compatible with the target we are using.
 148
 149 bool
 150 Parameters::is_compatible_target(const Target* target) const
 151 {
 152   if (this->target_ == NULL)
 153     return true;
 154   return target == this->target_;
 155 }
 156
 157 Parameters::Target_size_endianness
 158 Parameters::size_and_endianness() const
 159 {
 160   if (this->target().get_size() == 32)
 161     {
 162       if (!this->target().is_big_endian())
 163         {
 164 #ifdef HAVE_TARGET_32_LITTLE
 165           return TARGET_32_LITTLE;
 166 #else
 167           gold_unreachable();
 168 #endif
 169         }
 170       else
 171         {
 172 #ifdef HAVE_TARGET_32_BIG
 173           return TARGET_32_BIG;
 174 #else
 175           gold_unreachable();
 176 #endif
 177         }
 178     }
 179   else if (parameters->target().get_size() == 64)
 180     {
 181       if (!parameters->target().is_big_endian())
 182         {
 183 #ifdef HAVE_TARGET_64_LITTLE
 184           return TARGET_64_LITTLE;
 185 #else
 186           gold_unreachable();
 187 #endif
 188         }
 189       else
 190         {
 191 #ifdef HAVE_TARGET_64_BIG
 192           return TARGET_64_BIG;
 193 #else
 194           gold_unreachable();
 195 #endif
 196         }
 197     }
 198   else
 199     gold_unreachable();
 200 }
 201
 202 // If output endianness is specified in command line, check that it does
 203 // not conflict with the target.
 204
 205 void
 206 Parameters::check_target_endianness()
 207 {
 208   General_options::Endianness endianness = this->options().endianness();
 209   if (endianness != General_options::ENDIANNESS_NOT_SET)
 210     {
 211       bool big_endian;
 212       if (endianness == General_options::ENDIANNESS_BIG)
 213         big_endian = true;
 214       else
 215         {
 216           gold_assert(endianness == General_options::ENDIANNESS_LITTLE);
 217           big_endian = false;;
 218         }
 219
 220       if (this->target().is_big_endian() != big_endian)
 221         gold_error(_("input file does not match -EB/EL option"));
 222     }
 223 }
 224
 225 void
 226 Parameters::check_rodata_segment()
 227 {
 228   if (this->options().user_set_Trodata_segment()
 229       && !this->options().rosegment()
 230       && !this->target().isolate_execinstr())
 231     gold_error(_("-Trodata-segment is meaningless without --rosegment"));
 232 }
 233
 234 // Return the name of the entry symbol.
 235
 236 const char*
 237 Parameters::entry() const
 238 {
 239   const char* ret = this->options().entry();
 240   if (ret == NULL && parameters->target_valid())
 241     ret = parameters->target().entry_symbol_name();
 242   return ret;
 243 }
 244
 245 // Set the incremental linking mode to INCREMENTAL_FULL.  Used when
 246 // the linker determines that an incremental update is not possible.
 247 // Returns false if the incremental mode was INCREMENTAL_UPDATE,
 248 // indicating that the linker should exit if an update is not possible.
 249
 250 bool
 251 Parameters::set_incremental_full()
 252 {
 253   gold_assert(this->incremental_mode_ != General_options::INCREMENTAL_OFF);
 254   if (this->incremental_mode_ == General_options::INCREMENTAL_UPDATE)
 255     return false;
 256   this->incremental_mode_ = General_options::INCREMENTAL_FULL;
 257   return true;
 258 }
 259
 260 // Return true if we need to prepare incremental linking information.
 261
 262 bool
 263 Parameters::incremental() const
 264 {
 265   return this->incremental_mode_ != General_options::INCREMENTAL_OFF;
 266 }
 267
 268 // Return true if we are doing a full incremental link.
 269
 270 bool
 271 Parameters::incremental_full() const
 272 {
 273   return this->incremental_mode_ == General_options::INCREMENTAL_FULL;
 274 }
 275
 276 // Return true if we are doing an incremental update.
 277
 278 bool
 279 Parameters::incremental_update() const
 280 {
 281   return (this->incremental_mode_ == General_options::INCREMENTAL_UPDATE
 282           || this->incremental_mode_ == General_options::INCREMENTAL_AUTO);
 283 }
 284
 285 void
 286 set_parameters_errors(Errors* errors)
 287 { static_parameters.set_errors(errors); }
 288
 289 void
 290 set_parameters_timer(Timer* timer)
 291 { static_parameters.set_timer(timer); }
 292
 293 void
 294 set_parameters_options(const General_options* options)
 295 { static_parameters.set_options(options); }
 296
 297 void
 298 set_parameters_target(Target* target)
 299 {
 300   static_parameters.set_target(target);
 301 }
 302
 303 void
 304 set_parameters_doing_static_link(bool doing_static_link)
 305 { static_parameters.set_doing_static_link(doing_static_link); }
 306
 307 // Set the incremental linking mode to INCREMENTAL_FULL.  Used when
 308 // the linker determines that an incremental update is not possible.
 309 // Returns false if the incremental mode was INCREMENTAL_UPDATE,
 310 // indicating that the linker should exit if an update is not possible.
 311 bool
 312 set_parameters_incremental_full()
 313 { return static_parameters.set_incremental_full(); }
 314
 315 // Force the target to be valid by using the default.  Use the
 316 // --oformat option is set; this supports the x86_64 kernel build,
 317 // which converts a binary file to an object file using -r --format
 318 // binary --oformat elf32-i386 foo.o.  Otherwise use the configured
 319 // default.
 320
 321 void
 322 parameters_force_valid_target()
 323 {
 324   if (parameters->target_valid())
 325     return;
 326
 327   gold_assert(parameters->options_valid());
 328   if (parameters->options().user_set_oformat())
 329     {
 330       const char* bfd_name = parameters->options().oformat();
 331       Target* target = select_target_by_bfd_name(bfd_name);
 332       if (target != NULL)
 333         {
 334           set_parameters_target(target);
 335           return;
 336         }
 337
 338       gold_error(_("unrecognized output format %s"), bfd_name);
 339     }
 340
 341   if (parameters->options().user_set_m())
 342     {
 343       const char* emulation = parameters->options().m();
 344       Target* target = select_target_by_emulation(emulation);
 345       if (target != NULL)
 346         {
 347           set_parameters_target(target);
 348           return;
 349         }
 350
 351       gold_error(_("unrecognized emulation %s"), emulation);
 352     }
 353
 354   // The GOLD_DEFAULT_xx macros are defined by the configure script.
 355   bool is_big_endian;
 356   General_options::Endianness endianness = parameters->options().endianness();
 357   if (endianness == General_options::ENDIANNESS_BIG)
 358     is_big_endian = true;
 359   else if (endianness == General_options::ENDIANNESS_LITTLE)
 360     is_big_endian = false;
 361   else
 362     is_big_endian = GOLD_DEFAULT_BIG_ENDIAN;
 363
 364   Target* target = select_target(NULL, 0,
 365                                  elfcpp::GOLD_DEFAULT_MACHINE,
 366                                  GOLD_DEFAULT_SIZE,
 367                                  is_big_endian,
 368                                  elfcpp::GOLD_DEFAULT_OSABI,
 369                                  0);
 370
 371   if (target == NULL)
 372     {
 373       gold_assert(is_big_endian != GOLD_DEFAULT_BIG_ENDIAN);
 374       gold_fatal(_("no supported target for -EB/-EL option"));
 375     }
 376
 377   set_parameters_target(target);
 378 }
 379
 380 // Clear the current target, for testing.
 381
 382 void
 383 parameters_clear_target()
 384 {
 385   static_parameters.clear_target();
 386 }
 387
 388 } // End namespace gold.