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 "object.h"
  11 #include "archive.h"
  12 #include "readsyms.h"
  13
  14 namespace gold
  15 {
  16
  17 // Class read_symbols.
  18
  19 Read_symbols::~Read_symbols()
  20 {
  21   // The this_blocker_ and next_blocker_ pointers are passed on to the
  22   // Add_symbols task.
  23 }
  24
  25 // Return whether a Read_symbols task is runnable.  We can read an
  26 // ordinary input file immediately.  For an archive specified using
  27 // -l, we have to wait until the search path is complete.
  28
  29 Task::Is_runnable_type
  30 Read_symbols::is_runnable(Workqueue*)
  31 {
  32   if (this->input_.is_file()
  33       && this->input_.file().is_lib()
  34       && this->dirpath_.token().is_blocked())
  35     return IS_BLOCKED;
  36
  37   return IS_RUNNABLE;
  38 }
  39
  40 // Return a Task_locker for a Read_symbols task.  We don't need any
  41 // locks here.
  42
  43 Task_locker*
  44 Read_symbols::locks(Workqueue*)
  45 {
  46   return NULL;
  47 }
  48
  49 // Run a Read_symbols task.  This is where we actually read the
  50 // symbols and relocations.
  51
  52 void
  53 Read_symbols::run(Workqueue* workqueue)
  54 {
  55   if (this->input_.is_group())
  56     {
  57       assert(this->input_group_ == NULL);
  58       this->do_group(workqueue);
  59       return;
  60     }
  61
  62   Input_file* input_file = new Input_file(this->input_.file());
  63   input_file->open(this->options_, this->dirpath_);
  64
  65   // Read enough of the file to pick up the entire ELF header.
  66
  67   int ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
  68   off_t bytes;
  69   const unsigned char* p = input_file->file().get_view(0, ehdr_size, &bytes);
  70   if (bytes >= 4)
  71     {
  72       static unsigned char elfmagic[4] =
  73         {
  74           elfcpp::ELFMAG0, elfcpp::ELFMAG1,
  75           elfcpp::ELFMAG2, elfcpp::ELFMAG3
  76         };
  77       if (memcmp(p, elfmagic, 4) == 0)
  78         {
  79           // This is an ELF object.
  80
  81           if (this->input_group_ != NULL)
  82             {
  83               fprintf(stderr,
  84                       _("%s: %s: ordinary object found in input group\n"),
  85                       program_name, input_file->name());
  86               gold_exit(false);
  87             }
  88
  89           Object* obj = make_elf_object(this->input_.file().name(),
  90                                         input_file, 0, p, bytes);
  91
  92           Read_symbols_data* sd = new Read_symbols_data;
  93           obj->read_symbols(sd);
  94           workqueue->queue_front(new Add_symbols(this->input_objects_,
  95                                                  this->symtab_, this->layout_,
  96                                                  obj, sd,
  97                                                  this->this_blocker_,
  98                                                  this->next_blocker_));
  99
 100           // Opening the file locked it, so now we need to unlock it.
 101           input_file->file().unlock();
 102
 103           return;
 104         }
 105     }
 106
 107   if (bytes >= Archive::sarmag)
 108     {
 109       if (memcmp(p, Archive::armag, Archive::sarmag) == 0)
 110         {
 111           // This is an archive.
 112           Archive* arch = new Archive(this->input_.file().name(), input_file);
 113           arch->setup();
 114           workqueue->queue(new Add_archive_symbols(this->symtab_,
 115                                                    this->layout_,
 116                                                    this->input_objects_,
 117                                                    arch,
 118                                                    this->input_group_,
 119                                                    this->this_blocker_,
 120                                                    this->next_blocker_));
 121           return;
 122         }
 123     }
 124
 125   // Here we have to handle any other input file types we need.
 126   fprintf(stderr, _("%s: %s: not an object or archive\n"),
 127           program_name, input_file->file().filename().c_str());
 128   gold_exit(false);
 129 }
 130
 131 // Handle a group.  We need to walk through the arguments over and
 132 // over until we don't see any new undefined symbols.  We do this by
 133 // setting off Read_symbols Tasks as usual, but recording the archive
 134 // entries instead of deleting them.  We also start a Finish_group
 135 // Task which runs after we've read all the symbols.  In that task we
 136 // process the archives in a loop until we are done.
 137
 138 void
 139 Read_symbols::do_group(Workqueue* workqueue)
 140 {
 141   Input_group* input_group = new Input_group();
 142
 143   const Input_file_group* group = this->input_.group();
 144   Task_token* this_blocker = this->this_blocker_;
 145   for (Input_file_group::const_iterator p = group->begin();
 146        p != group->end();
 147        ++p)
 148     {
 149       const Input_argument& arg(*p);
 150       assert(arg.is_file());
 151
 152       Task_token* next_blocker = new Task_token();
 153       next_blocker->add_blocker();
 154       workqueue->queue(new Read_symbols(this->options_, this->input_objects_,
 155                                         this->symtab_, this->layout_,
 156                                         this->dirpath_, arg, input_group,
 157                                         this_blocker, next_blocker));
 158       this_blocker = next_blocker;
 159     }
 160
 161   const int saw_undefined = this->symtab_->saw_undefined();
 162   workqueue->queue(new Finish_group(this->input_objects_,
 163                                     this->symtab_,
 164                                     this->layout_,
 165                                     input_group,
 166                                     saw_undefined,
 167                                     this_blocker,
 168                                     this->next_blocker_));
 169 }
 170
 171 // Class Add_symbols.
 172
 173 Add_symbols::~Add_symbols()
 174 {
 175   if (this->this_blocker_ != NULL)
 176     delete this->this_blocker_;
 177   // next_blocker_ is deleted by the task associated with the next
 178   // input file.
 179 }
 180
 181 // We are blocked by this_blocker_.  We block next_blocker_.  We also
 182 // lock the file.
 183
 184 Task::Is_runnable_type
 185 Add_symbols::is_runnable(Workqueue*)
 186 {
 187   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 188     return IS_BLOCKED;
 189   if (this->object_->is_locked())
 190     return IS_LOCKED;
 191   return IS_RUNNABLE;
 192 }
 193
 194 class Add_symbols::Add_symbols_locker : public Task_locker
 195 {
 196  public:
 197   Add_symbols_locker(Task_token& token, Workqueue* workqueue,
 198                      Object* object)
 199     : blocker_(token, workqueue), objlock_(*object)
 200   { }
 201
 202  private:
 203   Task_locker_block blocker_;
 204   Task_locker_obj<Object> objlock_;
 205 };
 206
 207 Task_locker*
 208 Add_symbols::locks(Workqueue* workqueue)
 209 {
 210   return new Add_symbols_locker(*this->next_blocker_, workqueue,
 211                                 this->object_);
 212 }
 213
 214 // Add the symbols in the object to the symbol table.
 215
 216 void
 217 Add_symbols::run(Workqueue*)
 218 {
 219   this->input_objects_->add_object(this->object_);
 220   this->object_->layout(this->layout_, this->sd_);
 221   this->object_->add_symbols(this->symtab_, this->sd_);
 222   delete this->sd_;
 223   this->sd_ = NULL;
 224 }
 225
 226 // Class Finish_group.
 227
 228 Finish_group::~Finish_group()
 229 {
 230   if (this->this_blocker_ != NULL)
 231     delete this->this_blocker_;
 232   // next_blocker_ is deleted by the task associated with the next
 233   // input file following the group.
 234 }
 235
 236 // We need to wait for THIS_BLOCKER_ and unblock NEXT_BLOCKER_.
 237
 238 Task::Is_runnable_type
 239 Finish_group::is_runnable(Workqueue*)
 240 {
 241   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 242     return IS_BLOCKED;
 243   return IS_RUNNABLE;
 244 }
 245
 246 Task_locker*
 247 Finish_group::locks(Workqueue* workqueue)
 248 {
 249   return new Task_locker_block(*this->next_blocker_, workqueue);
 250 }
 251
 252 // Loop over the archives until there are no new undefined symbols.
 253
 254 void
 255 Finish_group::run(Workqueue*)
 256 {
 257   int saw_undefined = this->saw_undefined_;
 258   while (saw_undefined != this->symtab_->saw_undefined())
 259     {
 260       saw_undefined = this->symtab_->saw_undefined();
 261
 262       for (Input_group::const_iterator p = this->input_group_->begin();
 263            p != this->input_group_->end();
 264            ++p)
 265         {
 266           Task_lock_obj<Archive> tl(**p);
 267
 268           (*p)->add_symbols(this->symtab_, this->layout_,
 269                             this->input_objects_);
 270         }
 271     }
 272
 273   // Delete all the archives now that we no longer need them.
 274   for (Input_group::const_iterator p = this->input_group_->begin();
 275        p != this->input_group_->end();
 276        ++p)
 277     delete *p;
 278   delete this->input_group_;
 279 }
 280
 281 } // End namespace gold.