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[binutils.git] / gold / readsyms.cc
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1 // readsyms.cc -- read input file symbols for gold
3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
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.
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.
23 #include "gold.h"
25 #include <cstring>
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"
37 namespace gold
40 // If we fail to open the object, then we won't create an Add_symbols
41 // task. However, we still need to unblock the token, or else the
42 // link won't proceed to generate more error messages. We can only
43 // unblock tokens when the workqueue lock is held, so we need a dummy
44 // task to do that. The dummy task has to maintain the right sequence
45 // of blocks, so we need both this_blocker and next_blocker.
47 class Unblock_token : public Task
49 public:
50 Unblock_token(Task_token* this_blocker, Task_token* next_blocker)
51 : this_blocker_(this_blocker), next_blocker_(next_blocker)
52 { }
54 ~Unblock_token()
56 if (this->this_blocker_ != NULL)
57 delete this->this_blocker_;
60 Task_token*
61 is_runnable()
63 if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
64 return this->this_blocker_;
65 return NULL;
68 void
69 locks(Task_locker* tl)
70 { tl->add(this, this->next_blocker_); }
72 void
73 run(Workqueue*)
74 { }
76 std::string
77 get_name() const
78 { return "Unblock_token"; }
80 private:
81 Task_token* this_blocker_;
82 Task_token* next_blocker_;
85 // Class read_symbols.
87 Read_symbols::~Read_symbols()
89 // The this_blocker_ and next_blocker_ pointers are passed on to the
90 // Add_symbols task.
93 // Return whether a Read_symbols task is runnable. We can read an
94 // ordinary input file immediately. For an archive specified using
95 // -l, we have to wait until the search path is complete.
97 Task_token*
98 Read_symbols::is_runnable()
100 if (this->input_argument_->is_file()
101 && this->input_argument_->file().may_need_search()
102 && this->dirpath_->token()->is_blocked())
103 return this->dirpath_->token();
105 return NULL;
108 // Return a Task_locker for a Read_symbols task. We don't need any
109 // locks here.
111 void
112 Read_symbols::locks(Task_locker*)
116 // Run a Read_symbols task.
118 void
119 Read_symbols::run(Workqueue* workqueue)
121 // If we didn't queue a new task, then we need to explicitly unblock
122 // the token.
123 if (!this->do_read_symbols(workqueue))
124 workqueue->queue_soon(new Unblock_token(this->this_blocker_,
125 this->next_blocker_));
128 // Open the file and read the symbols. Return true if a new task was
129 // queued, false if that could not happen due to some error.
131 bool
132 Read_symbols::do_read_symbols(Workqueue* workqueue)
134 if (this->input_argument_->is_group())
136 gold_assert(this->input_group_ == NULL);
137 this->do_group(workqueue);
138 return true;
141 Input_file* input_file = new Input_file(&this->input_argument_->file());
142 if (!input_file->open(this->options_, *this->dirpath_, this))
143 return false;
145 // Read enough of the file to pick up the entire ELF header.
147 off_t filesize = input_file->file().filesize();
149 if (filesize == 0)
151 gold_error(_("%s: file is empty"),
152 input_file->file().filename().c_str());
153 return false;
156 int read_size = elfcpp::Elf_sizes<64>::ehdr_size;
157 if (filesize < read_size)
158 read_size = filesize;
160 const unsigned char* ehdr = input_file->file().get_view(0, 0, read_size,
161 true, false);
163 if (read_size >= Archive::sarmag)
165 bool is_thin_archive
166 = memcmp(ehdr, Archive::armagt, Archive::sarmag) == 0;
167 if (is_thin_archive
168 || memcmp(ehdr, Archive::armag, Archive::sarmag) == 0)
170 // This is an archive.
171 Archive* arch = new Archive(this->input_argument_->file().name(),
172 input_file, is_thin_archive,
173 this->dirpath_, this);
174 arch->setup(this->input_objects_);
176 // Unlock the archive so it can be used in the next task.
177 arch->unlock(this);
179 workqueue->queue_next(new Add_archive_symbols(this->symtab_,
180 this->layout_,
181 this->input_objects_,
182 this->mapfile_,
183 arch,
184 this->input_group_,
185 this->this_blocker_,
186 this->next_blocker_));
187 return true;
191 if (parameters->options().has_plugins())
193 Pluginobj* obj = parameters->options().plugins()->claim_file(input_file,
194 0, filesize);
195 if (obj != NULL)
197 // The input file was claimed by a plugin, and its symbols
198 // have been provided by the plugin.
199 input_file->file().claim_for_plugin();
200 input_file->file().unlock(this);
201 workqueue->queue_next(new Add_plugin_symbols(this->symtab_,
202 this->layout_,
203 obj,
204 this->this_blocker_,
205 this->next_blocker_));
206 return true;
210 if (read_size >= 4)
212 static unsigned char elfmagic[4] =
214 elfcpp::ELFMAG0, elfcpp::ELFMAG1,
215 elfcpp::ELFMAG2, elfcpp::ELFMAG3
217 if (memcmp(ehdr, elfmagic, 4) == 0)
219 // This is an ELF object.
221 Object* obj = make_elf_object(input_file->filename(),
222 input_file, 0, ehdr, read_size);
223 if (obj == NULL)
224 return false;
226 Read_symbols_data* sd = new Read_symbols_data;
227 obj->read_symbols(sd);
229 // Opening the file locked it, so now we need to unlock it.
230 // We need to unlock it before queuing the Add_symbols task,
231 // because the workqueue doesn't know about our lock on the
232 // file. If we queue the Add_symbols task first, it will be
233 // stuck on the end of the file lock, but since the
234 // workqueue doesn't know about that lock, it will never
235 // release the Add_symbols task.
237 input_file->file().unlock(this);
239 // We use queue_next because everything is cached for this
240 // task to run right away if possible.
242 workqueue->queue_next(new Add_symbols(this->input_objects_,
243 this->symtab_, this->layout_,
244 obj, sd,
245 this->this_blocker_,
246 this->next_blocker_));
248 return true;
252 // Queue up a task to try to parse this file as a script. We use a
253 // separate task so that the script will be read in order with other
254 // objects named on the command line. Also so that we don't try to
255 // read multiple scripts simultaneously, which could lead to
256 // unpredictable changes to the General_options structure.
258 workqueue->queue_soon(new Read_script(this->options_,
259 this->symtab_,
260 this->layout_,
261 this->dirpath_,
262 this->input_objects_,
263 this->mapfile_,
264 this->input_group_,
265 this->input_argument_,
266 input_file,
267 this->this_blocker_,
268 this->next_blocker_));
269 return true;
272 // Handle a group. We need to walk through the arguments over and
273 // over until we don't see any new undefined symbols. We do this by
274 // setting off Read_symbols Tasks as usual, but recording the archive
275 // entries instead of deleting them. We also start a Finish_group
276 // Task which runs after we've read all the symbols. In that task we
277 // process the archives in a loop until we are done.
279 void
280 Read_symbols::do_group(Workqueue* workqueue)
282 Input_group* input_group = new Input_group();
284 const Input_file_group* group = this->input_argument_->group();
285 Task_token* this_blocker = this->this_blocker_;
287 for (Input_file_group::const_iterator p = group->begin();
288 p != group->end();
289 ++p)
291 const Input_argument* arg = &*p;
292 gold_assert(arg->is_file());
294 Task_token* next_blocker = new Task_token(true);
295 next_blocker->add_blocker();
296 workqueue->queue_soon(new Read_symbols(this->options_,
297 this->input_objects_,
298 this->symtab_, this->layout_,
299 this->dirpath_, this->mapfile_,
300 arg, input_group,
301 this_blocker, next_blocker));
302 this_blocker = next_blocker;
305 const int saw_undefined = this->symtab_->saw_undefined();
306 workqueue->queue_soon(new Finish_group(this->input_objects_,
307 this->symtab_,
308 this->layout_,
309 this->mapfile_,
310 input_group,
311 saw_undefined,
312 this_blocker,
313 this->next_blocker_));
316 // Return a debugging name for a Read_symbols task.
318 std::string
319 Read_symbols::get_name() const
321 if (!this->input_argument_->is_group())
323 std::string ret("Read_symbols ");
324 if (this->input_argument_->file().is_lib())
325 ret += "-l";
326 ret += this->input_argument_->file().name();
327 return ret;
330 std::string ret("Read_symbols group (");
331 bool add_space = false;
332 const Input_file_group* group = this->input_argument_->group();
333 for (Input_file_group::const_iterator p = group->begin();
334 p != group->end();
335 ++p)
337 if (add_space)
338 ret += ' ';
339 ret += p->file().name();
340 add_space = true;
342 return ret + ')';
345 // Class Add_symbols.
347 Add_symbols::~Add_symbols()
349 if (this->this_blocker_ != NULL)
350 delete this->this_blocker_;
351 // next_blocker_ is deleted by the task associated with the next
352 // input file.
355 // We are blocked by this_blocker_. We block next_blocker_. We also
356 // lock the file.
358 Task_token*
359 Add_symbols::is_runnable()
361 if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
362 return this->this_blocker_;
363 if (this->object_->is_locked())
364 return this->object_->token();
365 return NULL;
368 void
369 Add_symbols::locks(Task_locker* tl)
371 tl->add(this, this->next_blocker_);
372 tl->add(this, this->object_->token());
375 // Add the symbols in the object to the symbol table.
377 void
378 Add_symbols::run(Workqueue*)
380 if (!this->input_objects_->add_object(this->object_))
382 // FIXME: We need to close the descriptor here.
383 delete this->object_;
385 else
387 this->object_->layout(this->symtab_, this->layout_, this->sd_);
388 this->object_->add_symbols(this->symtab_, this->sd_);
389 this->object_->release();
391 delete this->sd_;
392 this->sd_ = NULL;
395 // Class Finish_group.
397 Finish_group::~Finish_group()
399 if (this->this_blocker_ != NULL)
400 delete this->this_blocker_;
401 // next_blocker_ is deleted by the task associated with the next
402 // input file following the group.
405 // We need to wait for THIS_BLOCKER_ and unblock NEXT_BLOCKER_.
407 Task_token*
408 Finish_group::is_runnable()
410 if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
411 return this->this_blocker_;
412 return NULL;
415 void
416 Finish_group::locks(Task_locker* tl)
418 tl->add(this, this->next_blocker_);
421 // Loop over the archives until there are no new undefined symbols.
423 void
424 Finish_group::run(Workqueue*)
426 int saw_undefined = this->saw_undefined_;
427 while (saw_undefined != this->symtab_->saw_undefined())
429 saw_undefined = this->symtab_->saw_undefined();
431 for (Input_group::const_iterator p = this->input_group_->begin();
432 p != this->input_group_->end();
433 ++p)
435 Task_lock_obj<Archive> tl(this, *p);
437 (*p)->add_symbols(this->symtab_, this->layout_,
438 this->input_objects_, this->mapfile_);
442 // Delete all the archives now that we no longer need them.
443 for (Input_group::const_iterator p = this->input_group_->begin();
444 p != this->input_group_->end();
445 ++p)
446 delete *p;
447 delete this->input_group_;
450 // Class Read_script
452 Read_script::~Read_script()
454 if (this->this_blocker_ != NULL)
455 delete this->this_blocker_;
456 // next_blocker_ is deleted by the task associated with the next
457 // input file.
460 // We are blocked by this_blocker_.
462 Task_token*
463 Read_script::is_runnable()
465 if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
466 return this->this_blocker_;
467 return NULL;
470 // We don't unlock next_blocker_ here. If the script names any input
471 // files, then the last file will be responsible for unlocking it.
473 void
474 Read_script::locks(Task_locker*)
478 // Read the script, if it is a script.
480 void
481 Read_script::run(Workqueue* workqueue)
483 bool used_next_blocker;
484 if (!read_input_script(workqueue, this->options_, this->symtab_,
485 this->layout_, this->dirpath_, this->input_objects_,
486 this->mapfile_, this->input_group_,
487 this->input_argument_, this->input_file_,
488 this->next_blocker_, &used_next_blocker))
490 // Here we have to handle any other input file types we need.
491 gold_error(_("%s: not an object or archive"),
492 this->input_file_->file().filename().c_str());
495 if (!used_next_blocker)
497 // Queue up a task to unlock next_blocker. We can't just unlock
498 // it here, as we don't hold the workqueue lock.
499 workqueue->queue_soon(new Unblock_token(NULL, this->next_blocker_));
503 // Return a debugging name for a Read_script task.
505 std::string
506 Read_script::get_name() const
508 std::string ret("Read_script ");
509 if (this->input_argument_->file().is_lib())
510 ret += "-l";
511 ret += this->input_argument_->file().name();
512 return ret;
515 } // End namespace gold.