a6c04544e74fdccd015ef9aa947ab5eae1972705
[external/binutils.git] / gold / readsyms.cc
1 // readsyms.cc -- read input file symbols for gold
2
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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 #include "plugin.h"
36 #include "layout.h"
37 #include "incremental.h"
38
39 namespace gold
40 {
41
42 // If we fail to open the object, then we won't create an Add_symbols
43 // task.  However, we still need to unblock the token, or else the
44 // link won't proceed to generate more error messages.  We can only
45 // unblock tokens when the workqueue lock is held, so we need a dummy
46 // task to do that.  The dummy task has to maintain the right sequence
47 // of blocks, so we need both this_blocker and next_blocker.
48
49 class Unblock_token : public Task
50 {
51  public:
52   Unblock_token(Task_token* this_blocker, Task_token* next_blocker)
53     : this_blocker_(this_blocker), next_blocker_(next_blocker)
54   { }
55
56   ~Unblock_token()
57   {
58     if (this->this_blocker_ != NULL)
59       delete this->this_blocker_;
60   }
61
62   Task_token*
63   is_runnable()
64   {
65     if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
66       return this->this_blocker_;
67     return NULL;
68   }
69
70   void
71   locks(Task_locker* tl)
72   { tl->add(this, this->next_blocker_); }
73
74   void
75   run(Workqueue*)
76   { }
77
78   std::string
79   get_name() const
80   { return "Unblock_token"; }
81
82  private:
83   Task_token* this_blocker_;
84   Task_token* next_blocker_;
85 };
86
87 // Class read_symbols.
88
89 Read_symbols::~Read_symbols()
90 {
91   // The this_blocker_ and next_blocker_ pointers are passed on to the
92   // Add_symbols task.
93 }
94
95 // If appropriate, issue a warning about skipping an incompatible
96 // file.
97
98 void
99 Read_symbols::incompatible_warning(const Input_argument* input_argument,
100                                    const Input_file* input_file)
101 {
102   if (parameters->options().warn_search_mismatch())
103     gold_warning("skipping incompatible %s while searching for %s",
104                  input_file->filename().c_str(),
105                  input_argument->file().name());
106 }
107
108 // Requeue a Read_symbols task to search for the next object with the
109 // same name.
110
111 void
112 Read_symbols::requeue(Workqueue* workqueue, Input_objects* input_objects,
113                       Symbol_table* symtab, Layout* layout, Dirsearch* dirpath,
114                       int dirindex, Mapfile* mapfile,
115                       const Input_argument* input_argument,
116                       Input_group* input_group, Task_token* next_blocker)
117 {
118   // Bump the directory search index.
119   ++dirindex;
120
121   // We don't need to worry about this_blocker, since we already
122   // reached it.  However, we are removing the blocker on next_blocker
123   // because the calling task is completing.  So we need to add a new
124   // blocker.  Since next_blocker may be shared by several tasks, we
125   // need to increment the count with the workqueue lock held.
126   workqueue->add_blocker(next_blocker);
127
128   workqueue->queue(new Read_symbols(input_objects, symtab, layout, dirpath,
129                                     dirindex, mapfile, input_argument,
130                                     input_group, NULL, NULL, next_blocker));
131 }
132
133 // Return whether a Read_symbols task is runnable.  We can read an
134 // ordinary input file immediately.  For an archive specified using
135 // -l, we have to wait until the search path is complete.
136
137 Task_token*
138 Read_symbols::is_runnable()
139 {
140   if (this->input_argument_->is_file()
141       && this->input_argument_->file().may_need_search()
142       && this->dirpath_->token()->is_blocked())
143     return this->dirpath_->token();
144
145   return NULL;
146 }
147
148 // Return a Task_locker for a Read_symbols task.  We don't need any
149 // locks here.
150
151 void
152 Read_symbols::locks(Task_locker* tl)
153 {
154   if (this->member_ != NULL)
155     tl->add(this, this->next_blocker_);
156 }
157
158 // Run a Read_symbols task.
159
160 void
161 Read_symbols::run(Workqueue* workqueue)
162 {
163   // If we didn't queue a new task, then we need to explicitly unblock
164   // the token.
165   if (!this->do_read_symbols(workqueue))
166     workqueue->queue_soon(new Unblock_token(this->this_blocker_,
167                                             this->next_blocker_));
168 }
169
170 // Handle a whole lib group. Other than collecting statistics, this just
171 // mimics what we do for regular object files in the command line.
172
173 bool
174 Read_symbols::do_whole_lib_group(Workqueue* workqueue)
175 {
176   const Input_file_lib* lib_group = this->input_argument_->lib();
177
178   ++Lib_group::total_lib_groups;
179
180   Task_token* this_blocker = this->this_blocker_;
181   for (Input_file_lib::const_iterator i = lib_group->begin();
182        i != lib_group->end();
183        ++i)
184     {
185       ++Lib_group::total_members;
186       ++Lib_group::total_members_loaded;
187
188       const Input_argument* arg = &*i;
189
190       Task_token* next_blocker;
191       if (i != lib_group->end() - 1)
192         {
193           next_blocker = new Task_token(true);
194           next_blocker->add_blocker();
195         }
196       else
197         next_blocker = this->next_blocker_;
198
199       workqueue->queue_soon(new Read_symbols(this->input_objects_,
200                                              this->symtab_, this->layout_,
201                                              this->dirpath_, this->dirindex_,
202                                              this->mapfile_, arg, NULL,
203                                              NULL, this_blocker, next_blocker));
204       this_blocker = next_blocker;
205     }
206
207   return true;
208 }
209
210 // Handle a lib group. We set Read_symbols Tasks as usual, but have them
211 // just record the symbol data instead of adding the objects.  We also start
212 // a Add_lib_group_symbols Task which runs after we've read all the symbols.
213 // In that task we process the members in a loop until we are done.
214
215 bool
216 Read_symbols::do_lib_group(Workqueue* workqueue)
217 {
218   const Input_file_lib* lib_group = this->input_argument_->lib();
219
220   if (lib_group->options().whole_archive())
221     return this->do_whole_lib_group(workqueue);
222
223   Lib_group* lib = new Lib_group(lib_group, this);
224
225   Add_lib_group_symbols* add_lib_group_symbols =
226     new Add_lib_group_symbols(this->symtab_, this->layout_,
227                               this->input_objects_,
228                               lib, this->next_blocker_);
229
230
231   Task_token* next_blocker = new Task_token(true);
232   int j = 0;
233   for (Input_file_lib::const_iterator i = lib_group->begin();
234        i != lib_group->end();
235        ++i, ++j)
236     {
237       const Input_argument* arg = &*i;
238       Archive_member* m = lib->get_member(j);
239
240       next_blocker->add_blocker();
241
242       // Since this Read_symbols will not create an Add_symbols,
243       // just pass NULL as this_blocker.
244       workqueue->queue_soon(new Read_symbols(this->input_objects_,
245                                              this->symtab_, this->layout_,
246                                              this->dirpath_, this->dirindex_,
247                                              this->mapfile_, arg, NULL,
248                                              m, NULL, next_blocker));
249     }
250
251   add_lib_group_symbols->set_blocker(next_blocker, this->this_blocker_);
252   workqueue->queue_soon(add_lib_group_symbols);
253
254   return true;
255 }
256
257 // Open the file and read the symbols.  Return true if a new task was
258 // queued, false if that could not happen due to some error.
259
260 bool
261 Read_symbols::do_read_symbols(Workqueue* workqueue)
262 {
263   if (this->input_argument_->is_group())
264     {
265       gold_assert(this->input_group_ == NULL);
266       this->do_group(workqueue);
267       return true;
268     }
269
270   if (this->input_argument_->is_lib())
271     return this->do_lib_group(workqueue);
272
273   Input_file* input_file = new Input_file(&this->input_argument_->file());
274   if (!input_file->open(*this->dirpath_, this, &this->dirindex_))
275     return false;
276
277   // Read enough of the file to pick up the entire ELF header.
278
279   off_t filesize = input_file->file().filesize();
280
281   if (filesize == 0)
282     {
283       gold_error(_("%s: file is empty"),
284                  input_file->file().filename().c_str());
285       return false;
286     }
287
288   const unsigned char* ehdr;
289   int read_size;
290   bool is_elf = is_elf_object(input_file, 0, &ehdr, &read_size);
291
292   if (read_size >= Archive::sarmag)
293     {
294       bool is_thin_archive
295           = memcmp(ehdr, Archive::armagt, Archive::sarmag) == 0;
296       if (is_thin_archive
297           || memcmp(ehdr, Archive::armag, Archive::sarmag) == 0)
298         {
299           // This is an archive.
300           Archive* arch = new Archive(this->input_argument_->file().name(),
301                                       input_file, is_thin_archive,
302                                       this->dirpath_, this);
303           arch->setup();
304
305           // Unlock the archive so it can be used in the next task.
306           arch->unlock(this);
307
308           workqueue->queue_next(new Add_archive_symbols(this->symtab_,
309                                                         this->layout_,
310                                                         this->input_objects_,
311                                                         this->dirpath_,
312                                                         this->dirindex_,
313                                                         this->mapfile_,
314                                                         this->input_argument_,
315                                                         arch,
316                                                         this->input_group_,
317                                                         this->this_blocker_,
318                                                         this->next_blocker_));
319           return true;
320         }
321     }
322
323   if (parameters->options().has_plugins())
324     {
325       Pluginobj* obj = parameters->options().plugins()->claim_file(input_file,
326                                                                    0, filesize);
327       if (obj != NULL)
328         {
329           // The input file was claimed by a plugin, and its symbols
330           // have been provided by the plugin.
331
332           // We are done with the file at this point, so unlock it.
333           obj->unlock(this);
334
335           if (this->member_ != NULL)
336             {
337               this->member_->sd_ = NULL;
338               this->member_->obj_ = obj;
339               return true;
340             }
341
342           workqueue->queue_next(new Add_symbols(this->input_objects_,
343                                                 this->symtab_,
344                                                 this->layout_,
345                                                 this->dirpath_,
346                                                 this->dirindex_,
347                                                 this->mapfile_,
348                                                 this->input_argument_,
349                                                 obj,
350                                                 NULL,
351                                                 this->this_blocker_,
352                                                 this->next_blocker_));
353           return true;
354         }
355     }
356
357   if (is_elf)
358     {
359       // This is an ELF object.
360
361       bool unconfigured = false;
362       bool* punconfigured = (input_file->will_search_for()
363                              ? &unconfigured
364                              : NULL);
365       Object* obj = make_elf_object(input_file->filename(),
366                                     input_file, 0, ehdr, read_size,
367                                     punconfigured);
368       if (obj == NULL)
369         {
370           if (unconfigured)
371             {
372               Read_symbols::incompatible_warning(this->input_argument_,
373                                                  input_file);
374               input_file->file().release();
375               input_file->file().unlock(this);
376               delete input_file;
377               ++this->dirindex_;
378               return this->do_read_symbols(workqueue);
379             }
380           return false;
381         }
382
383       Read_symbols_data* sd = new Read_symbols_data;
384       obj->read_symbols(sd);
385
386       // Opening the file locked it, so now we need to unlock it.  We
387       // need to unlock it before queuing the Add_symbols task,
388       // because the workqueue doesn't know about our lock on the
389       // file.  If we queue the Add_symbols task first, it will be
390       // stuck on the end of the file lock, but since the workqueue
391       // doesn't know about that lock, it will never release the
392       // Add_symbols task.
393
394       input_file->file().unlock(this);
395
396       if (this->member_ != NULL)
397         {
398           this->member_->sd_ = sd;
399           this->member_->obj_ = obj;
400           return true;
401         }
402
403       // We use queue_next because everything is cached for this
404       // task to run right away if possible.
405
406       workqueue->queue_next(new Add_symbols(this->input_objects_,
407                                             this->symtab_, this->layout_,
408                                             this->dirpath_,
409                                             this->dirindex_,
410                                             this->mapfile_,
411                                             this->input_argument_,
412                                             obj,
413                                             sd,
414                                             this->this_blocker_,
415                                             this->next_blocker_));
416
417       return true;
418     }
419
420   // Queue up a task to try to parse this file as a script.  We use a
421   // separate task so that the script will be read in order with other
422   // objects named on the command line.  Also so that we don't try to
423   // read multiple scripts simultaneously, which could lead to
424   // unpredictable changes to the General_options structure.
425
426   workqueue->queue_soon(new Read_script(this->symtab_,
427                                         this->layout_,
428                                         this->dirpath_,
429                                         this->dirindex_,
430                                         this->input_objects_,
431                                         this->mapfile_,
432                                         this->input_group_,
433                                         this->input_argument_,
434                                         input_file,
435                                         this->this_blocker_,
436                                         this->next_blocker_));
437   return true;
438 }
439
440 // Handle a group.  We need to walk through the arguments over and
441 // over until we don't see any new undefined symbols.  We do this by
442 // setting off Read_symbols Tasks as usual, but recording the archive
443 // entries instead of deleting them.  We also start a Finish_group
444 // Task which runs after we've read all the symbols.  In that task we
445 // process the archives in a loop until we are done.
446
447 void
448 Read_symbols::do_group(Workqueue* workqueue)
449 {
450   Input_group* input_group = new Input_group();
451
452   const Input_file_group* group = this->input_argument_->group();
453   Task_token* this_blocker = this->this_blocker_;
454
455   Finish_group* finish_group = new Finish_group(this->input_objects_,
456                                                 this->symtab_,
457                                                 this->layout_,
458                                                 this->mapfile_,
459                                                 input_group,
460                                                 this->next_blocker_);
461
462   Task_token* next_blocker = new Task_token(true);
463   next_blocker->add_blocker();
464   workqueue->queue_soon(new Start_group(this->symtab_, finish_group,
465                                         this_blocker, next_blocker));
466   this_blocker = next_blocker;
467
468   for (Input_file_group::const_iterator p = group->begin();
469        p != group->end();
470        ++p)
471     {
472       const Input_argument* arg = &*p;
473       gold_assert(arg->is_file());
474
475       next_blocker = new Task_token(true);
476       next_blocker->add_blocker();
477       workqueue->queue_soon(new Read_symbols(this->input_objects_,
478                                              this->symtab_, this->layout_,
479                                              this->dirpath_, this->dirindex_,
480                                              this->mapfile_, arg, input_group,
481                                              NULL, this_blocker, next_blocker));
482       this_blocker = next_blocker;
483     }
484
485   finish_group->set_blocker(this_blocker);
486
487   workqueue->queue_soon(finish_group);
488 }
489
490 // Return a debugging name for a Read_symbols task.
491
492 std::string
493 Read_symbols::get_name() const
494 {
495   if (this->input_argument_->is_group())
496     {
497       std::string ret("Read_symbols group (");
498       bool add_space = false;
499       const Input_file_group* group = this->input_argument_->group();
500       for (Input_file_group::const_iterator p = group->begin();
501            p != group->end();
502            ++p)
503       {
504         if (add_space)
505           ret += ' ';
506         ret += p->file().name();
507         add_space = true;
508       }
509       return ret + ')';
510     }
511   else if (this->input_argument_->is_lib())
512     {
513       std::string ret("Read_symbols lib (");
514       bool add_space = false;
515       const Input_file_lib* lib = this->input_argument_->lib();
516       for (Input_file_lib::const_iterator p = lib->begin();
517            p != lib->end();
518            ++p)
519       {
520         if (add_space)
521           ret += ' ';
522         ret += p->file().name();
523         add_space = true;
524       }
525       return ret + ')';
526     }
527   else
528     {
529       std::string ret("Read_symbols ");
530       if (this->input_argument_->file().is_lib())
531         ret += "-l";
532       else if (this->input_argument_->file().is_searched_file())
533         ret += "-l:";
534       ret += this->input_argument_->file().name();
535       return ret;
536     }
537 }
538
539 // Class Add_symbols.
540
541 Add_symbols::~Add_symbols()
542 {
543   if (this->this_blocker_ != NULL)
544     delete this->this_blocker_;
545   // next_blocker_ is deleted by the task associated with the next
546   // input file.
547 }
548
549 // We are blocked by this_blocker_.  We block next_blocker_.  We also
550 // lock the file.
551
552 Task_token*
553 Add_symbols::is_runnable()
554 {
555   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
556     return this->this_blocker_;
557   if (this->object_->is_locked())
558     return this->object_->token();
559   return NULL;
560 }
561
562 void
563 Add_symbols::locks(Task_locker* tl)
564 {
565   tl->add(this, this->next_blocker_);
566   tl->add(this, this->object_->token());
567 }
568
569 // Add the symbols in the object to the symbol table.
570
571 void
572 Add_symbols::run(Workqueue*)
573 {
574   Pluginobj* pluginobj = this->object_->pluginobj();
575   if (pluginobj != NULL)
576     {
577       this->object_->add_symbols(this->symtab_, this->sd_, this->layout_);
578       return;
579     }
580
581   if (!this->input_objects_->add_object(this->object_))
582     {
583       delete this->sd_;
584       this->sd_ = NULL;
585       this->object_->release();
586       delete this->object_;
587     }
588   else
589     {
590       Incremental_inputs* incremental_inputs =
591           this->layout_->incremental_inputs();
592       if (incremental_inputs != NULL)
593         incremental_inputs->report_object(this->object_, NULL,
594                                           this->input_argument_->script_info());
595       this->object_->layout(this->symtab_, this->layout_, this->sd_);
596       this->object_->add_symbols(this->symtab_, this->sd_, this->layout_);
597       delete this->sd_;
598       this->sd_ = NULL;
599       this->object_->release();
600     }
601 }
602
603 // Class Input_group.
604
605 // When we delete an Input_group we can delete the archive
606 // information.
607
608 Input_group::~Input_group()
609 {
610   for (Input_group::const_iterator p = this->begin();
611        p != this->end();
612        ++p)
613     delete *p;
614 }
615
616 // Class Start_group.
617
618 Start_group::~Start_group()
619 {
620   if (this->this_blocker_ != NULL)
621     delete this->this_blocker_;
622   // next_blocker_ is deleted by the task associated with the first
623   // file in the group.
624 }
625
626 // We need to wait for THIS_BLOCKER_ and unblock NEXT_BLOCKER_.
627
628 Task_token*
629 Start_group::is_runnable()
630 {
631   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
632     return this->this_blocker_;
633   return NULL;
634 }
635
636 void
637 Start_group::locks(Task_locker* tl)
638 {
639   tl->add(this, this->next_blocker_);
640 }
641
642 // Store the number of undefined symbols we see now.
643
644 void
645 Start_group::run(Workqueue*)
646 {
647   this->finish_group_->set_saw_undefined(this->symtab_->saw_undefined());
648 }
649
650 // Class Finish_group.
651
652 Finish_group::~Finish_group()
653 {
654   if (this->this_blocker_ != NULL)
655     delete this->this_blocker_;
656   // next_blocker_ is deleted by the task associated with the next
657   // input file following the group.
658 }
659
660 // We need to wait for THIS_BLOCKER_ and unblock NEXT_BLOCKER_.
661
662 Task_token*
663 Finish_group::is_runnable()
664 {
665   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
666     return this->this_blocker_;
667   return NULL;
668 }
669
670 void
671 Finish_group::locks(Task_locker* tl)
672 {
673   tl->add(this, this->next_blocker_);
674 }
675
676 // Loop over the archives until there are no new undefined symbols.
677
678 void
679 Finish_group::run(Workqueue*)
680 {
681   size_t saw_undefined = this->saw_undefined_;
682   while (saw_undefined != this->symtab_->saw_undefined())
683     {
684       saw_undefined = this->symtab_->saw_undefined();
685
686       for (Input_group::const_iterator p = this->input_group_->begin();
687            p != this->input_group_->end();
688            ++p)
689         {
690           Task_lock_obj<Archive> tl(this, *p);
691
692           (*p)->add_symbols(this->symtab_, this->layout_,
693                             this->input_objects_, this->mapfile_);
694         }
695     }
696
697   // Now that we're done with the archives, record the incremental
698   // layout information.
699   for (Input_group::const_iterator p = this->input_group_->begin();
700        p != this->input_group_->end();
701        ++p)
702     {
703       // For an incremental link, finish recording the layout information.
704       Incremental_inputs* incremental_inputs =
705           this->layout_->incremental_inputs();
706       if (incremental_inputs != NULL)
707         incremental_inputs->report_archive_end(*p);
708     }
709
710   if (parameters->options().has_plugins())
711     parameters->options().plugins()->save_input_group(this->input_group_);
712   else
713     delete this->input_group_;
714 }
715
716 // Class Read_script
717
718 Read_script::~Read_script()
719 {
720   if (this->this_blocker_ != NULL)
721     delete this->this_blocker_;
722   // next_blocker_ is deleted by the task associated with the next
723   // input file.
724 }
725
726 // We are blocked by this_blocker_.
727
728 Task_token*
729 Read_script::is_runnable()
730 {
731   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
732     return this->this_blocker_;
733   return NULL;
734 }
735
736 // We don't unlock next_blocker_ here.  If the script names any input
737 // files, then the last file will be responsible for unlocking it.
738
739 void
740 Read_script::locks(Task_locker*)
741 {
742 }
743
744 // Read the script, if it is a script.
745
746 void
747 Read_script::run(Workqueue* workqueue)
748 {
749   bool used_next_blocker;
750   if (!read_input_script(workqueue, this->symtab_, this->layout_,
751                          this->dirpath_, this->dirindex_, this->input_objects_,
752                          this->mapfile_, this->input_group_,
753                          this->input_argument_, this->input_file_,
754                          this->next_blocker_, &used_next_blocker))
755     {
756       // Here we have to handle any other input file types we need.
757       gold_error(_("%s: not an object or archive"),
758                  this->input_file_->file().filename().c_str());
759     }
760
761   if (!used_next_blocker)
762     {
763       // Queue up a task to unlock next_blocker.  We can't just unlock
764       // it here, as we don't hold the workqueue lock.
765       workqueue->queue_soon(new Unblock_token(NULL, this->next_blocker_));
766     }
767 }
768
769 // Return a debugging name for a Read_script task.
770
771 std::string
772 Read_script::get_name() const
773 {
774   std::string ret("Read_script ");
775   if (this->input_argument_->file().is_lib())
776     ret += "-l";
777   else if (this->input_argument_->file().is_searched_file())
778     ret += "-l:";
779   ret += this->input_argument_->file().name();
780   return ret;
781 }
782
783 } // End namespace gold.