gold/readsyms.cc

   1 // readsyms.cc -- read input file symbols for gold
   2
   3 // Copyright 2006, 2007 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 <cstring>
  26
  27 #include "elfcpp.h"
  28 #include "options.h"
  29 #include "dirsearch.h"
  30 #include "symtab.h"
  31 #include "object.h"
  32 #include "archive.h"
  33 #include "script.h"
  34 #include "readsyms.h"
  35
  36 namespace gold
  37 {
  38
  39 // Class read_symbols.
  40
  41 Read_symbols::~Read_symbols()
  42 {
  43   // The this_blocker_ and next_blocker_ pointers are passed on to the
  44   // Add_symbols task.
  45 }
  46
  47 // Return whether a Read_symbols task is runnable.  We can read an
  48 // ordinary input file immediately.  For an archive specified using
  49 // -l, we have to wait until the search path is complete.
  50
  51 Task::Is_runnable_type
  52 Read_symbols::is_runnable(Workqueue*)
  53 {
  54   if (this->input_argument_->is_file()
  55       && this->input_argument_->file().is_lib()
  56       && this->dirpath_.token().is_blocked())
  57     return IS_BLOCKED;
  58
  59   return IS_RUNNABLE;
  60 }
  61
  62 // Return a Task_locker for a Read_symbols task.  We don't need any
  63 // locks here.
  64
  65 Task_locker*
  66 Read_symbols::locks(Workqueue*)
  67 {
  68   return NULL;
  69 }
  70
  71 // Run a Read_symbols task.  This is where we actually read the
  72 // symbols and relocations.
  73
  74 void
  75 Read_symbols::run(Workqueue* workqueue)
  76 {
  77   if (this->input_argument_->is_group())
  78     {
  79       gold_assert(this->input_group_ == NULL);
  80       this->do_group(workqueue);
  81       return;
  82     }
  83
  84   Input_file* input_file = new Input_file(&this->input_argument_->file());
  85   input_file->open(this->options_, this->dirpath_);
  86
  87   // Read enough of the file to pick up the entire ELF header.
  88
  89   int ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
  90   off_t bytes;
  91   const unsigned char* p = input_file->file().get_view(0, ehdr_size, &bytes);
  92   if (bytes >= 4)
  93     {
  94       static unsigned char elfmagic[4] =
  95         {
  96           elfcpp::ELFMAG0, elfcpp::ELFMAG1,
  97           elfcpp::ELFMAG2, elfcpp::ELFMAG3
  98         };
  99       if (memcmp(p, elfmagic, 4) == 0)
 100         {
 101           // This is an ELF object.
 102
 103           Object* obj = make_elf_object(input_file->filename(),
 104                                         input_file, 0, p, bytes);
 105
 106           // We don't have a way to record a non-archive in an input
 107           // group.  If this is an ordinary object file, we can't
 108           // include it more than once anyhow.  If this is a dynamic
 109           // object, then including it a second time changes nothing.
 110           if (this->input_group_ != NULL && !obj->is_dynamic())
 111             {
 112               fprintf(stderr,
 113                       _("%s: %s: ordinary object found in input group\n"),
 114                       program_name, input_file->name());
 115               gold_exit(false);
 116             }
 117
 118           Read_symbols_data* sd = new Read_symbols_data;
 119           obj->read_symbols(sd);
 120           workqueue->queue_front(new Add_symbols(this->input_objects_,
 121                                                  this->symtab_, this->layout_,
 122                                                  obj, sd,
 123                                                  this->this_blocker_,
 124                                                  this->next_blocker_));
 125
 126           // Opening the file locked it, so now we need to unlock it.
 127           input_file->file().unlock();
 128
 129           return;
 130         }
 131     }
 132
 133   if (bytes >= Archive::sarmag)
 134     {
 135       if (memcmp(p, Archive::armag, Archive::sarmag) == 0)
 136         {
 137           // This is an archive.
 138           Archive* arch = new Archive(this->input_argument_->file().name(),
 139                                       input_file);
 140           arch->setup();
 141           workqueue->queue(new Add_archive_symbols(this->symtab_,
 142                                                    this->layout_,
 143                                                    this->input_objects_,
 144                                                    arch,
 145                                                    this->input_group_,
 146                                                    this->this_blocker_,
 147                                                    this->next_blocker_));
 148           return;
 149         }
 150     }
 151
 152   if (bytes == 0)
 153     {
 154       fprintf(stderr, _("%s: %s: file is empty\n"),
 155               program_name, input_file->file().filename().c_str());
 156       gold_exit(false);
 157     }
 158
 159   // Try to parse this file as a script.
 160   if (read_input_script(workqueue, this->options_, this->symtab_,
 161                         this->layout_, this->dirpath_, this->input_objects_,
 162                         this->input_group_, this->input_argument_, input_file,
 163                         p, bytes, this->this_blocker_, this->next_blocker_))
 164     return;
 165
 166   // Here we have to handle any other input file types we need.
 167   fprintf(stderr, _("%s: %s: not an object or archive\n"),
 168           program_name, input_file->file().filename().c_str());
 169   gold_exit(false);
 170 }
 171
 172 // Handle a group.  We need to walk through the arguments over and
 173 // over until we don't see any new undefined symbols.  We do this by
 174 // setting off Read_symbols Tasks as usual, but recording the archive
 175 // entries instead of deleting them.  We also start a Finish_group
 176 // Task which runs after we've read all the symbols.  In that task we
 177 // process the archives in a loop until we are done.
 178
 179 void
 180 Read_symbols::do_group(Workqueue* workqueue)
 181 {
 182   Input_group* input_group = new Input_group();
 183
 184   const Input_file_group* group = this->input_argument_->group();
 185   Task_token* this_blocker = this->this_blocker_;
 186   for (Input_file_group::const_iterator p = group->begin();
 187        p != group->end();
 188        ++p)
 189     {
 190       const Input_argument* arg = &*p;
 191       gold_assert(arg->is_file());
 192
 193       Task_token* next_blocker = new Task_token();
 194       next_blocker->add_blocker();
 195       workqueue->queue(new Read_symbols(this->options_, this->input_objects_,
 196                                         this->symtab_, this->layout_,
 197                                         this->dirpath_, arg, input_group,
 198                                         this_blocker, next_blocker));
 199       this_blocker = next_blocker;
 200     }
 201
 202   const int saw_undefined = this->symtab_->saw_undefined();
 203   workqueue->queue(new Finish_group(this->input_objects_,
 204                                     this->symtab_,
 205                                     this->layout_,
 206                                     input_group,
 207                                     saw_undefined,
 208                                     this_blocker,
 209                                     this->next_blocker_));
 210 }
 211
 212 // Class Add_symbols.
 213
 214 Add_symbols::~Add_symbols()
 215 {
 216   if (this->this_blocker_ != NULL)
 217     delete this->this_blocker_;
 218   // next_blocker_ is deleted by the task associated with the next
 219   // input file.
 220 }
 221
 222 // We are blocked by this_blocker_.  We block next_blocker_.  We also
 223 // lock the file.
 224
 225 Task::Is_runnable_type
 226 Add_symbols::is_runnable(Workqueue*)
 227 {
 228   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 229     return IS_BLOCKED;
 230   if (this->object_->is_locked())
 231     return IS_LOCKED;
 232   return IS_RUNNABLE;
 233 }
 234
 235 class Add_symbols::Add_symbols_locker : public Task_locker
 236 {
 237  public:
 238   Add_symbols_locker(Task_token& token, Workqueue* workqueue,
 239                      Object* object)
 240     : blocker_(token, workqueue), objlock_(*object)
 241   { }
 242
 243  private:
 244   Task_locker_block blocker_;
 245   Task_locker_obj<Object> objlock_;
 246 };
 247
 248 Task_locker*
 249 Add_symbols::locks(Workqueue* workqueue)
 250 {
 251   return new Add_symbols_locker(*this->next_blocker_, workqueue,
 252                                 this->object_);
 253 }
 254
 255 // Add the symbols in the object to the symbol table.
 256
 257 void
 258 Add_symbols::run(Workqueue*)
 259 {
 260   if (!this->input_objects_->add_object(this->object_))
 261     {
 262       // FIXME: We need to close the descriptor here.
 263       delete this->object_;
 264     }
 265   else
 266     {
 267       this->object_->layout(this->symtab_, this->layout_, this->sd_);
 268       this->object_->add_symbols(this->symtab_, this->sd_);
 269     }
 270   delete this->sd_;
 271   this->sd_ = NULL;
 272 }
 273
 274 // Class Finish_group.
 275
 276 Finish_group::~Finish_group()
 277 {
 278   if (this->this_blocker_ != NULL)
 279     delete this->this_blocker_;
 280   // next_blocker_ is deleted by the task associated with the next
 281   // input file following the group.
 282 }
 283
 284 // We need to wait for THIS_BLOCKER_ and unblock NEXT_BLOCKER_.
 285
 286 Task::Is_runnable_type
 287 Finish_group::is_runnable(Workqueue*)
 288 {
 289   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 290     return IS_BLOCKED;
 291   return IS_RUNNABLE;
 292 }
 293
 294 Task_locker*
 295 Finish_group::locks(Workqueue* workqueue)
 296 {
 297   return new Task_locker_block(*this->next_blocker_, workqueue);
 298 }
 299
 300 // Loop over the archives until there are no new undefined symbols.
 301
 302 void
 303 Finish_group::run(Workqueue*)
 304 {
 305   int saw_undefined = this->saw_undefined_;
 306   while (saw_undefined != this->symtab_->saw_undefined())
 307     {
 308       saw_undefined = this->symtab_->saw_undefined();
 309
 310       for (Input_group::const_iterator p = this->input_group_->begin();
 311            p != this->input_group_->end();
 312            ++p)
 313         {
 314           Task_lock_obj<Archive> tl(**p);
 315
 316           (*p)->add_symbols(this->symtab_, this->layout_,
 317                             this->input_objects_);
 318         }
 319     }
 320
 321   // Delete all the archives now that we no longer need them.
 322   for (Input_group::const_iterator p = this->input_group_->begin();
 323        p != this->input_group_->end();
 324        ++p)
 325     delete *p;
 326   delete this->input_group_;
 327 }
 328
 329 } // End namespace gold.