gold/readsyms.cc

   1 // readsyms.cc -- read input file symbols for gold
   2
   3 #include "gold.h"
   4
   5 #include <cstring>
   6
   7 #include "elfcpp.h"
   8 #include "options.h"
   9 #include "dirsearch.h"
  10 #include "symtab.h"
  11 #include "object.h"
  12 #include "archive.h"
  13 #include "script.h"
  14 #include "readsyms.h"
  15
  16 namespace gold
  17 {
  18
  19 // Class read_symbols.
  20
  21 Read_symbols::~Read_symbols()
  22 {
  23   // The this_blocker_ and next_blocker_ pointers are passed on to the
  24   // Add_symbols task.
  25 }
  26
  27 // Return whether a Read_symbols task is runnable.  We can read an
  28 // ordinary input file immediately.  For an archive specified using
  29 // -l, we have to wait until the search path is complete.
  30
  31 Task::Is_runnable_type
  32 Read_symbols::is_runnable(Workqueue*)
  33 {
  34   if (this->input_argument_->is_file()
  35       && this->input_argument_->file().is_lib()
  36       && this->dirpath_.token().is_blocked())
  37     return IS_BLOCKED;
  38
  39   return IS_RUNNABLE;
  40 }
  41
  42 // Return a Task_locker for a Read_symbols task.  We don't need any
  43 // locks here.
  44
  45 Task_locker*
  46 Read_symbols::locks(Workqueue*)
  47 {
  48   return NULL;
  49 }
  50
  51 // Run a Read_symbols task.  This is where we actually read the
  52 // symbols and relocations.
  53
  54 void
  55 Read_symbols::run(Workqueue* workqueue)
  56 {
  57   if (this->input_argument_->is_group())
  58     {
  59       gold_assert(this->input_group_ == NULL);
  60       this->do_group(workqueue);
  61       return;
  62     }
  63
  64   Input_file* input_file = new Input_file(&this->input_argument_->file());
  65   input_file->open(this->options_, this->dirpath_);
  66
  67   // Read enough of the file to pick up the entire ELF header.
  68
  69   int ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
  70   off_t bytes;
  71   const unsigned char* p = input_file->file().get_view(0, ehdr_size, &bytes);
  72   if (bytes >= 4)
  73     {
  74       static unsigned char elfmagic[4] =
  75         {
  76           elfcpp::ELFMAG0, elfcpp::ELFMAG1,
  77           elfcpp::ELFMAG2, elfcpp::ELFMAG3
  78         };
  79       if (memcmp(p, elfmagic, 4) == 0)
  80         {
  81           // This is an ELF object.
  82
  83           Object* obj = make_elf_object(input_file->filename(),
  84                                         input_file, 0, p, bytes);
  85
  86           // We don't have a way to record a non-archive in an input
  87           // group.  If this is an ordinary object file, we can't
  88           // include it more than once anyhow.  If this is a dynamic
  89           // object, then including it a second time changes nothing.
  90           if (this->input_group_ != NULL && !obj->is_dynamic())
  91             {
  92               fprintf(stderr,
  93                       _("%s: %s: ordinary object found in input group\n"),
  94                       program_name, input_file->name());
  95               gold_exit(false);
  96             }
  97
  98           Read_symbols_data* sd = new Read_symbols_data;
  99           obj->read_symbols(sd);
 100           workqueue->queue_front(new Add_symbols(this->options_,
 101                                                  this->input_objects_,
 102                                                  this->symtab_, this->layout_,
 103                                                  obj, sd,
 104                                                  this->this_blocker_,
 105                                                  this->next_blocker_));
 106
 107           // Opening the file locked it, so now we need to unlock it.
 108           input_file->file().unlock();
 109
 110           return;
 111         }
 112     }
 113
 114   if (bytes >= Archive::sarmag)
 115     {
 116       if (memcmp(p, Archive::armag, Archive::sarmag) == 0)
 117         {
 118           // This is an archive.
 119           Archive* arch = new Archive(this->input_argument_->file().name(),
 120                                       input_file);
 121           arch->setup();
 122           workqueue->queue(new Add_archive_symbols(this->options_,
 123                                                    this->symtab_,
 124                                                    this->layout_,
 125                                                    this->input_objects_,
 126                                                    arch,
 127                                                    this->input_group_,
 128                                                    this->this_blocker_,
 129                                                    this->next_blocker_));
 130           return;
 131         }
 132     }
 133
 134   if (bytes == 0)
 135     {
 136       fprintf(stderr, _("%s: %s: file is empty\n"),
 137               program_name, input_file->file().filename().c_str());
 138       gold_exit(false);
 139     }
 140
 141   // Try to parse this file as a script.
 142   if (read_input_script(workqueue, this->options_, this->symtab_,
 143                         this->layout_, this->dirpath_, this->input_objects_,
 144                         this->input_group_, this->input_argument_, input_file,
 145                         p, bytes, this->this_blocker_, this->next_blocker_))
 146     return;
 147
 148   // Here we have to handle any other input file types we need.
 149   fprintf(stderr, _("%s: %s: not an object or archive\n"),
 150           program_name, input_file->file().filename().c_str());
 151   gold_exit(false);
 152 }
 153
 154 // Handle a group.  We need to walk through the arguments over and
 155 // over until we don't see any new undefined symbols.  We do this by
 156 // setting off Read_symbols Tasks as usual, but recording the archive
 157 // entries instead of deleting them.  We also start a Finish_group
 158 // Task which runs after we've read all the symbols.  In that task we
 159 // process the archives in a loop until we are done.
 160
 161 void
 162 Read_symbols::do_group(Workqueue* workqueue)
 163 {
 164   Input_group* input_group = new Input_group();
 165
 166   const Input_file_group* group = this->input_argument_->group();
 167   Task_token* this_blocker = this->this_blocker_;
 168   for (Input_file_group::const_iterator p = group->begin();
 169        p != group->end();
 170        ++p)
 171     {
 172       const Input_argument* arg = &*p;
 173       gold_assert(arg->is_file());
 174
 175       Task_token* next_blocker = new Task_token();
 176       next_blocker->add_blocker();
 177       workqueue->queue(new Read_symbols(this->options_, this->input_objects_,
 178                                         this->symtab_, this->layout_,
 179                                         this->dirpath_, arg, input_group,
 180                                         this_blocker, next_blocker));
 181       this_blocker = next_blocker;
 182     }
 183
 184   const int saw_undefined = this->symtab_->saw_undefined();
 185   workqueue->queue(new Finish_group(this->options_,
 186                                     this->input_objects_,
 187                                     this->symtab_,
 188                                     this->layout_,
 189                                     input_group,
 190                                     saw_undefined,
 191                                     this_blocker,
 192                                     this->next_blocker_));
 193 }
 194
 195 // Class Add_symbols.
 196
 197 Add_symbols::~Add_symbols()
 198 {
 199   if (this->this_blocker_ != NULL)
 200     delete this->this_blocker_;
 201   // next_blocker_ is deleted by the task associated with the next
 202   // input file.
 203 }
 204
 205 // We are blocked by this_blocker_.  We block next_blocker_.  We also
 206 // lock the file.
 207
 208 Task::Is_runnable_type
 209 Add_symbols::is_runnable(Workqueue*)
 210 {
 211   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 212     return IS_BLOCKED;
 213   if (this->object_->is_locked())
 214     return IS_LOCKED;
 215   return IS_RUNNABLE;
 216 }
 217
 218 class Add_symbols::Add_symbols_locker : public Task_locker
 219 {
 220  public:
 221   Add_symbols_locker(Task_token& token, Workqueue* workqueue,
 222                      Object* object)
 223     : blocker_(token, workqueue), objlock_(*object)
 224   { }
 225
 226  private:
 227   Task_locker_block blocker_;
 228   Task_locker_obj<Object> objlock_;
 229 };
 230
 231 Task_locker*
 232 Add_symbols::locks(Workqueue* workqueue)
 233 {
 234   return new Add_symbols_locker(*this->next_blocker_, workqueue,
 235                                 this->object_);
 236 }
 237
 238 // Add the symbols in the object to the symbol table.
 239
 240 void
 241 Add_symbols::run(Workqueue*)
 242 {
 243   if (!this->input_objects_->add_object(this->object_))
 244     {
 245       // FIXME: We need to close the descriptor here.
 246       delete this->object_;
 247     }
 248   else
 249     {
 250       this->object_->layout(this->options_, this->symtab_, this->layout_,
 251                             this->sd_);
 252       this->object_->add_symbols(this->symtab_, this->sd_);
 253     }
 254   delete this->sd_;
 255   this->sd_ = NULL;
 256 }
 257
 258 // Class Finish_group.
 259
 260 Finish_group::~Finish_group()
 261 {
 262   if (this->this_blocker_ != NULL)
 263     delete this->this_blocker_;
 264   // next_blocker_ is deleted by the task associated with the next
 265   // input file following the group.
 266 }
 267
 268 // We need to wait for THIS_BLOCKER_ and unblock NEXT_BLOCKER_.
 269
 270 Task::Is_runnable_type
 271 Finish_group::is_runnable(Workqueue*)
 272 {
 273   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 274     return IS_BLOCKED;
 275   return IS_RUNNABLE;
 276 }
 277
 278 Task_locker*
 279 Finish_group::locks(Workqueue* workqueue)
 280 {
 281   return new Task_locker_block(*this->next_blocker_, workqueue);
 282 }
 283
 284 // Loop over the archives until there are no new undefined symbols.
 285
 286 void
 287 Finish_group::run(Workqueue*)
 288 {
 289   int saw_undefined = this->saw_undefined_;
 290   while (saw_undefined != this->symtab_->saw_undefined())
 291     {
 292       saw_undefined = this->symtab_->saw_undefined();
 293
 294       for (Input_group::const_iterator p = this->input_group_->begin();
 295            p != this->input_group_->end();
 296            ++p)
 297         {
 298           Task_lock_obj<Archive> tl(**p);
 299
 300           (*p)->add_symbols(this->options_, this->symtab_, this->layout_,
 301                             this->input_objects_);
 302         }
 303     }
 304
 305   // Delete all the archives now that we no longer need them.
 306   for (Input_group::const_iterator p = this->input_group_->begin();
 307        p != this->input_group_->end();
 308        ++p)
 309     delete *p;
 310   delete this->input_group_;
 311 }
 312
 313 } // End namespace gold.