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      1 // parameters.cc -- general parameters for a link using gold
      2 
      3 // Copyright (C) 2006-2014 Free Software Foundation, Inc.
      4 // Written by Ian Lance Taylor <iant (at) 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)
    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.
    389