gold/plugin.cc

   1 // plugin.cc -- plugin manager for gold      -*- C++ -*-
   2
   3 // Copyright 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   4 // Written by Cary Coutant <ccoutant@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 <cstdio>
  26 #include <cstdarg>
  27 #include <cstring>
  28 #include <string>
  29 #include <vector>
  30
  31 #ifdef ENABLE_PLUGINS
  32 #include <dlfcn.h>
  33 #endif
  34
  35 #include "parameters.h"
  36 #include "errors.h"
  37 #include "fileread.h"
  38 #include "layout.h"
  39 #include "options.h"
  40 #include "plugin.h"
  41 #include "target.h"
  42 #include "readsyms.h"
  43 #include "symtab.h"
  44 #include "elfcpp.h"
  45
  46 namespace gold
  47 {
  48
  49 #ifdef ENABLE_PLUGINS
  50
  51 // The linker's exported interfaces.
  52
  53 extern "C"
  54 {
  55
  56 static enum ld_plugin_status
  57 register_claim_file(ld_plugin_claim_file_handler handler);
  58
  59 static enum ld_plugin_status
  60 register_all_symbols_read(ld_plugin_all_symbols_read_handler handler);
  61
  62 static enum ld_plugin_status
  63 register_cleanup(ld_plugin_cleanup_handler handler);
  64
  65 static enum ld_plugin_status
  66 add_symbols(void *handle, int nsyms, const struct ld_plugin_symbol *syms);
  67
  68 static enum ld_plugin_status
  69 get_input_file(const void *handle, struct ld_plugin_input_file *file);
  70
  71 static enum ld_plugin_status
  72 release_input_file(const void *handle);
  73
  74 static enum ld_plugin_status
  75 get_symbols(const void *handle, int nsyms, struct ld_plugin_symbol *syms);
  76
  77 static enum ld_plugin_status
  78 add_input_file(const char *pathname);
  79
  80 static enum ld_plugin_status
  81 add_input_library(const char *pathname);
  82
  83 static enum ld_plugin_status
  84 set_extra_library_path(const char *path);
  85
  86 static enum ld_plugin_status
  87 message(int level, const char *format, ...);
  88
  89 };
  90
  91 #endif // ENABLE_PLUGINS
  92
  93 static Pluginobj* make_sized_plugin_object(Input_file* input_file,
  94                                            off_t offset, off_t filesize);
  95
  96 // Plugin methods.
  97
  98 // Load one plugin library.
  99
 100 void
 101 Plugin::load()
 102 {
 103 #ifdef ENABLE_PLUGINS
 104   // Load the plugin library.
 105   // FIXME: Look for the library in standard locations.
 106   this->handle_ = dlopen(this->filename_.c_str(), RTLD_NOW);
 107   if (this->handle_ == NULL)
 108     {
 109       gold_error(_("%s: could not load plugin library: %s"),
 110                  this->filename_.c_str(), dlerror());
 111       return;
 112     }
 113
 114   // Find the plugin's onload entry point.
 115   void* ptr = dlsym(this->handle_, "onload");
 116   if (ptr == NULL)
 117     {
 118       gold_error(_("%s: could not find onload entry point"),
 119                  this->filename_.c_str());
 120       return;
 121     }
 122   ld_plugin_onload onload;
 123   gold_assert(sizeof(onload) == sizeof(ptr));
 124   memcpy(&onload, &ptr, sizeof(ptr));
 125
 126   // Get the linker's version number.
 127   const char* ver = get_version_string();
 128   int major = 0;
 129   int minor = 0;
 130   sscanf(ver, "%d.%d", &major, &minor);
 131
 132   // Allocate and populate a transfer vector.
 133   const int tv_fixed_size = 16;
 134   int tv_size = this->args_.size() + tv_fixed_size;
 135   ld_plugin_tv* tv = new ld_plugin_tv[tv_size];
 136
 137   // Put LDPT_MESSAGE at the front of the list so the plugin can use it
 138   // while processing subsequent entries.
 139   int i = 0;
 140   tv[i].tv_tag = LDPT_MESSAGE;
 141   tv[i].tv_u.tv_message = message;
 142
 143   ++i;
 144   tv[i].tv_tag = LDPT_API_VERSION;
 145   tv[i].tv_u.tv_val = LD_PLUGIN_API_VERSION;
 146
 147   ++i;
 148   tv[i].tv_tag = LDPT_GOLD_VERSION;
 149   tv[i].tv_u.tv_val = major * 100 + minor;
 150
 151   ++i;
 152   tv[i].tv_tag = LDPT_LINKER_OUTPUT;
 153   if (parameters->options().relocatable())
 154     tv[i].tv_u.tv_val = LDPO_REL;
 155   else if (parameters->options().shared())
 156     tv[i].tv_u.tv_val = LDPO_DYN;
 157   else
 158     tv[i].tv_u.tv_val = LDPO_EXEC;
 159
 160   ++i;
 161   tv[i].tv_tag = LDPT_OUTPUT_NAME;
 162   tv[i].tv_u.tv_string = parameters->options().output();
 163
 164   for (unsigned int j = 0; j < this->args_.size(); ++j)
 165     {
 166       ++i;
 167       tv[i].tv_tag = LDPT_OPTION;
 168       tv[i].tv_u.tv_string = this->args_[j].c_str();
 169     }
 170
 171   ++i;
 172   tv[i].tv_tag = LDPT_REGISTER_CLAIM_FILE_HOOK;
 173   tv[i].tv_u.tv_register_claim_file = register_claim_file;
 174
 175   ++i;
 176   tv[i].tv_tag = LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK;
 177   tv[i].tv_u.tv_register_all_symbols_read = register_all_symbols_read;
 178
 179   ++i;
 180   tv[i].tv_tag = LDPT_REGISTER_CLEANUP_HOOK;
 181   tv[i].tv_u.tv_register_cleanup = register_cleanup;
 182
 183   ++i;
 184   tv[i].tv_tag = LDPT_ADD_SYMBOLS;
 185   tv[i].tv_u.tv_add_symbols = add_symbols;
 186
 187   ++i;
 188   tv[i].tv_tag = LDPT_GET_INPUT_FILE;
 189   tv[i].tv_u.tv_get_input_file = get_input_file;
 190
 191   ++i;
 192   tv[i].tv_tag = LDPT_RELEASE_INPUT_FILE;
 193   tv[i].tv_u.tv_release_input_file = release_input_file;
 194
 195   ++i;
 196   tv[i].tv_tag = LDPT_GET_SYMBOLS;
 197   tv[i].tv_u.tv_get_symbols = get_symbols;
 198
 199   ++i;
 200   tv[i].tv_tag = LDPT_ADD_INPUT_FILE;
 201   tv[i].tv_u.tv_add_input_file = add_input_file;
 202
 203   ++i;
 204   tv[i].tv_tag = LDPT_ADD_INPUT_LIBRARY;
 205   tv[i].tv_u.tv_add_input_library = add_input_library;
 206
 207   ++i;
 208   tv[i].tv_tag = LDPT_SET_EXTRA_LIBRARY_PATH;
 209   tv[i].tv_u.tv_set_extra_library_path = set_extra_library_path;
 210
 211   ++i;
 212   tv[i].tv_tag = LDPT_NULL;
 213   tv[i].tv_u.tv_val = 0;
 214
 215   gold_assert(i == tv_size - 1);
 216
 217   // Call the onload entry point.
 218   (*onload)(tv);
 219
 220   delete[] tv;
 221 #endif // ENABLE_PLUGINS
 222 }
 223
 224 // Call the plugin claim-file handler.
 225
 226 inline bool
 227 Plugin::claim_file(struct ld_plugin_input_file* plugin_input_file)
 228 {
 229   int claimed = 0;
 230
 231   if (this->claim_file_handler_ != NULL)
 232     {
 233       (*this->claim_file_handler_)(plugin_input_file, &claimed);
 234       if (claimed)
 235         return true;
 236     }
 237   return false;
 238 }
 239
 240 // Call the all-symbols-read handler.
 241
 242 inline void
 243 Plugin::all_symbols_read()
 244 {
 245   if (this->all_symbols_read_handler_ != NULL)
 246     (*this->all_symbols_read_handler_)();
 247 }
 248
 249 // Call the cleanup handler.
 250
 251 inline void
 252 Plugin::cleanup()
 253 {
 254   if (this->cleanup_handler_ != NULL && !this->cleanup_done_)
 255     {
 256       // Set this flag before calling to prevent a recursive plunge
 257       // in the event that a plugin's cleanup handler issues a
 258       // fatal error.
 259       this->cleanup_done_ = true;
 260       (*this->cleanup_handler_)();
 261     }
 262 }
 263
 264 // This task is used to rescan archives as needed.
 265
 266 class Plugin_rescan : public Task
 267 {
 268  public:
 269   Plugin_rescan(Task_token* this_blocker, Task_token* next_blocker)
 270     : this_blocker_(this_blocker), next_blocker_(next_blocker)
 271   { }
 272
 273   ~Plugin_rescan()
 274   {
 275     delete this->this_blocker_;
 276   }
 277
 278   Task_token*
 279   is_runnable()
 280   {
 281     if (this->this_blocker_->is_blocked())
 282       return this->this_blocker_;
 283     return NULL;
 284   }
 285
 286   void
 287   locks(Task_locker* tl)
 288   { tl->add(this, this->next_blocker_); }
 289
 290   void
 291   run(Workqueue*)
 292   { parameters->options().plugins()->rescan(this); }
 293
 294   std::string
 295   get_name() const
 296   { return "Plugin_rescan"; }
 297
 298  private:
 299   Task_token* this_blocker_;
 300   Task_token* next_blocker_;
 301 };
 302
 303 // Plugin_manager methods.
 304
 305 Plugin_manager::~Plugin_manager()
 306 {
 307   for (Plugin_list::iterator p = this->plugins_.begin();
 308        p != this->plugins_.end();
 309        ++p)
 310     delete *p;
 311   this->plugins_.clear();
 312   for (Object_list::iterator obj = this->objects_.begin();
 313        obj != this->objects_.end();
 314        ++obj)
 315     delete *obj;
 316   this->objects_.clear();
 317 }
 318
 319 // Load all plugin libraries.
 320
 321 void
 322 Plugin_manager::load_plugins()
 323 {
 324   for (this->current_ = this->plugins_.begin();
 325        this->current_ != this->plugins_.end();
 326        ++this->current_)
 327     (*this->current_)->load();
 328 }
 329
 330 // Call the plugin claim-file handlers in turn to see if any claim the file.
 331
 332 Pluginobj*
 333 Plugin_manager::claim_file(Input_file* input_file, off_t offset,
 334                            off_t filesize)
 335 {
 336   if (this->in_replacement_phase_)
 337     return NULL;
 338
 339   unsigned int handle = this->objects_.size();
 340   this->input_file_ = input_file;
 341   this->plugin_input_file_.name = input_file->filename().c_str();
 342   this->plugin_input_file_.fd = input_file->file().descriptor();
 343   this->plugin_input_file_.offset = offset;
 344   this->plugin_input_file_.filesize = filesize;
 345   this->plugin_input_file_.handle = reinterpret_cast<void*>(handle);
 346
 347   for (this->current_ = this->plugins_.begin();
 348        this->current_ != this->plugins_.end();
 349        ++this->current_)
 350     {
 351       if ((*this->current_)->claim_file(&this->plugin_input_file_))
 352         {
 353           this->any_claimed_ = true;
 354
 355           if (this->objects_.size() > handle)
 356             return this->objects_[handle];
 357
 358           // If the plugin claimed the file but did not call the
 359           // add_symbols callback, we need to create the Pluginobj now.
 360           Pluginobj* obj = this->make_plugin_object(handle);
 361           return obj;
 362         }
 363     }
 364
 365   return NULL;
 366 }
 367
 368 // Save an archive.  This is used so that a plugin can add a file
 369 // which refers to a symbol which was not previously referenced.  In
 370 // that case we want to pretend that the symbol was referenced before,
 371 // and pull in the archive object.
 372
 373 void
 374 Plugin_manager::save_archive(Archive* archive)
 375 {
 376   if (this->in_replacement_phase_ || !this->any_claimed_)
 377     delete archive;
 378   else
 379     this->rescannable_.push_back(Rescannable(archive));
 380 }
 381
 382 // Save an Input_group.  This is like save_archive.
 383
 384 void
 385 Plugin_manager::save_input_group(Input_group* input_group)
 386 {
 387   if (this->in_replacement_phase_ || !this->any_claimed_)
 388     delete input_group;
 389   else
 390     this->rescannable_.push_back(Rescannable(input_group));
 391 }
 392
 393 // Call the all-symbols-read handlers.
 394
 395 void
 396 Plugin_manager::all_symbols_read(Workqueue* workqueue, Task* task,
 397                                  Input_objects* input_objects,
 398                                  Symbol_table* symtab, Layout* layout,
 399                                  Dirsearch* dirpath, Mapfile* mapfile,
 400                                  Task_token** last_blocker)
 401 {
 402   this->in_replacement_phase_ = true;
 403   this->workqueue_ = workqueue;
 404   this->task_ = task;
 405   this->input_objects_ = input_objects;
 406   this->symtab_ = symtab;
 407   this->layout_ = layout;
 408   this->dirpath_ = dirpath;
 409   this->mapfile_ = mapfile;
 410   this->this_blocker_ = NULL;
 411
 412   for (this->current_ = this->plugins_.begin();
 413        this->current_ != this->plugins_.end();
 414        ++this->current_)
 415     (*this->current_)->all_symbols_read();
 416
 417   if (this->any_added_)
 418     {
 419       Task_token* next_blocker = new Task_token(true);
 420       next_blocker->add_blocker();
 421       workqueue->queue(new Plugin_rescan(this->this_blocker_, next_blocker));
 422       this->this_blocker_ = next_blocker;
 423     }
 424
 425   *last_blocker = this->this_blocker_;
 426 }
 427
 428 // This is called when we see a new undefined symbol.  If we are in
 429 // the replacement phase, this means that we may need to rescan some
 430 // archives we have previously seen.
 431
 432 void
 433 Plugin_manager::new_undefined_symbol(Symbol* sym)
 434 {
 435   if (this->in_replacement_phase_)
 436     this->undefined_symbols_.push_back(sym);
 437 }
 438
 439 // Rescan archives as needed.  This handles the case where a new
 440 // object file added by a plugin has an undefined reference to some
 441 // symbol defined in an archive.
 442
 443 void
 444 Plugin_manager::rescan(Task* task)
 445 {
 446   size_t rescan_pos = 0;
 447   size_t rescan_size = this->rescannable_.size();
 448   while (!this->undefined_symbols_.empty())
 449     {
 450       if (rescan_pos >= rescan_size)
 451         {
 452           this->undefined_symbols_.clear();
 453           return;
 454         }
 455
 456       Undefined_symbol_list undefs;
 457       undefs.reserve(this->undefined_symbols_.size());
 458       this->undefined_symbols_.swap(undefs);
 459
 460       size_t min_rescan_pos = rescan_size;
 461
 462       for (Undefined_symbol_list::const_iterator p = undefs.begin();
 463            p != undefs.end();
 464            ++p)
 465         {
 466           if (!(*p)->is_undefined())
 467             continue;
 468
 469           this->undefined_symbols_.push_back(*p);
 470
 471           // Find the first rescan archive which defines this symbol,
 472           // starting at the current rescan position.  The rescan position
 473           // exists so that given -la -lb -lc we don't look for undefined
 474           // symbols in -lb back in -la, but instead get the definition
 475           // from -lc.  Don't bother to look past the current minimum
 476           // rescan position.
 477           for (size_t i = rescan_pos; i < min_rescan_pos; ++i)
 478             {
 479               if (this->rescannable_defines(i, *p))
 480                 {
 481                   min_rescan_pos = i;
 482                   break;
 483                 }
 484             }
 485         }
 486
 487       if (min_rescan_pos >= rescan_size)
 488         {
 489           // We didn't find any rescannable archives which define any
 490           // undefined symbols.
 491           return;
 492         }
 493
 494       const Rescannable& r(this->rescannable_[min_rescan_pos]);
 495       if (r.is_archive)
 496         {
 497           Task_lock_obj<Archive> tl(task, r.u.archive);
 498           r.u.archive->add_symbols(this->symtab_, this->layout_,
 499                                    this->input_objects_, this->mapfile_);
 500         }
 501       else
 502         {
 503           size_t next_saw_undefined = this->symtab_->saw_undefined();
 504           size_t saw_undefined;
 505           do
 506             {
 507               saw_undefined = next_saw_undefined;
 508
 509               for (Input_group::const_iterator p = r.u.input_group->begin();
 510                    p != r.u.input_group->end();
 511                    ++p)
 512                 {
 513                   Task_lock_obj<Archive> tl(task, *p);
 514
 515                   (*p)->add_symbols(this->symtab_, this->layout_,
 516                                     this->input_objects_, this->mapfile_);
 517                 }
 518
 519               next_saw_undefined = this->symtab_->saw_undefined();
 520             }
 521           while (saw_undefined != next_saw_undefined);
 522         }
 523
 524       for (size_t i = rescan_pos; i < min_rescan_pos + 1; ++i)
 525         {
 526           if (this->rescannable_[i].is_archive)
 527             delete this->rescannable_[i].u.archive;
 528           else
 529             delete this->rescannable_[i].u.input_group;
 530         }
 531
 532       rescan_pos = min_rescan_pos + 1;
 533     }
 534 }
 535
 536 // Return whether the rescannable at index I defines SYM.
 537
 538 bool
 539 Plugin_manager::rescannable_defines(size_t i, Symbol* sym)
 540 {
 541   const Rescannable& r(this->rescannable_[i]);
 542   if (r.is_archive)
 543     return r.u.archive->defines_symbol(sym);
 544   else
 545     {
 546       for (Input_group::const_iterator p = r.u.input_group->begin();
 547            p != r.u.input_group->end();
 548            ++p)
 549         {
 550           if ((*p)->defines_symbol(sym))
 551             return true;
 552         }
 553       return false;
 554     }
 555 }
 556
 557 // Layout deferred objects.
 558
 559 void
 560 Plugin_manager::layout_deferred_objects()
 561 {
 562   Deferred_layout_list::iterator obj;
 563
 564   for (obj = this->deferred_layout_objects_.begin();
 565        obj != this->deferred_layout_objects_.end();
 566        ++obj)
 567     {
 568       // Lock the object so we can read from it.  This is only called
 569       // single-threaded from queue_middle_tasks, so it is OK to lock.
 570       // Unfortunately we have no way to pass in a Task token.
 571       const Task* dummy_task = reinterpret_cast<const Task*>(-1);
 572       Task_lock_obj<Object> tl(dummy_task, *obj);
 573       (*obj)->layout_deferred_sections(this->layout_);
 574     }
 575 }
 576
 577 // Call the cleanup handlers.
 578
 579 void
 580 Plugin_manager::cleanup()
 581 {
 582   for (this->current_ = this->plugins_.begin();
 583        this->current_ != this->plugins_.end();
 584        ++this->current_)
 585     (*this->current_)->cleanup();
 586 }
 587
 588 // Make a new Pluginobj object.  This is called when the plugin calls
 589 // the add_symbols API.
 590
 591 Pluginobj*
 592 Plugin_manager::make_plugin_object(unsigned int handle)
 593 {
 594   // Make sure we aren't asked to make an object for the same handle twice.
 595   if (this->objects_.size() != handle)
 596     return NULL;
 597
 598   Pluginobj* obj = make_sized_plugin_object(this->input_file_,
 599                                             this->plugin_input_file_.offset,
 600                                             this->plugin_input_file_.filesize);
 601   this->objects_.push_back(obj);
 602   return obj;
 603 }
 604
 605 // Get the input file information with an open (possibly re-opened)
 606 // file descriptor.
 607
 608 ld_plugin_status
 609 Plugin_manager::get_input_file(unsigned int handle,
 610                                struct ld_plugin_input_file* file)
 611 {
 612   Pluginobj* obj = this->object(handle);
 613   if (obj == NULL)
 614     return LDPS_BAD_HANDLE;
 615
 616   obj->lock(this->task_);
 617   file->name = obj->filename().c_str();
 618   file->fd = obj->descriptor();
 619   file->offset = obj->offset();
 620   file->filesize = obj->filesize();
 621   file->handle = reinterpret_cast<void*>(handle);
 622   return LDPS_OK;
 623 }
 624
 625 // Release the input file.
 626
 627 ld_plugin_status
 628 Plugin_manager::release_input_file(unsigned int handle)
 629 {
 630   Pluginobj* obj = this->object(handle);
 631   if (obj == NULL)
 632     return LDPS_BAD_HANDLE;
 633
 634   obj->unlock(this->task_);
 635   return LDPS_OK;
 636 }
 637
 638 // Add a new library path.
 639
 640 ld_plugin_status
 641 Plugin_manager::set_extra_library_path(const char* path)
 642 {
 643   this->extra_search_path_ = std::string(path);
 644   return LDPS_OK;
 645 }
 646
 647 // Add a new input file.
 648
 649 ld_plugin_status
 650 Plugin_manager::add_input_file(const char* pathname, bool is_lib)
 651 {
 652   Input_file_argument file(pathname,
 653                            (is_lib
 654                             ? Input_file_argument::INPUT_FILE_TYPE_LIBRARY
 655                             : Input_file_argument::INPUT_FILE_TYPE_FILE),
 656                            (is_lib
 657                             ? this->extra_search_path_.c_str()
 658                             : ""),
 659                            false,
 660                            this->options_);
 661   Input_argument* input_argument = new Input_argument(file);
 662   Task_token* next_blocker = new Task_token(true);
 663   next_blocker->add_blocker();
 664   if (parameters->incremental())
 665     gold_error(_("input files added by plug-ins in --incremental mode not "
 666                  "supported yet"));
 667   this->workqueue_->queue_soon(new Read_symbols(this->input_objects_,
 668                                                 this->symtab_,
 669                                                 this->layout_,
 670                                                 this->dirpath_,
 671                                                 0,
 672                                                 this->mapfile_,
 673                                                 input_argument,
 674                                                 NULL,
 675                                                 NULL,
 676                                                 this->this_blocker_,
 677                                                 next_blocker));
 678   this->this_blocker_ = next_blocker;
 679   this->any_added_ = true;
 680   return LDPS_OK;
 681 }
 682
 683 // Class Pluginobj.
 684
 685 Pluginobj::Pluginobj(const std::string& name, Input_file* input_file,
 686                      off_t offset, off_t filesize)
 687   : Object(name, input_file, false, offset),
 688     nsyms_(0), syms_(NULL), symbols_(), filesize_(filesize), comdat_map_()
 689 {
 690 }
 691
 692 // Return TRUE if a defined symbol might be reachable from outside the
 693 // universe of claimed objects.
 694
 695 static inline bool
 696 is_visible_from_outside(Symbol* lsym)
 697 {
 698   if (lsym->in_real_elf())
 699     return true;
 700   if (parameters->options().relocatable())
 701     return true;
 702   if (parameters->options().is_undefined(lsym->name()))
 703     return true;
 704   if (parameters->options().export_dynamic() || parameters->options().shared())
 705     return lsym->is_externally_visible();
 706   return false;
 707 }
 708
 709 // Get symbol resolution info.
 710
 711 ld_plugin_status
 712 Pluginobj::get_symbol_resolution_info(int nsyms, ld_plugin_symbol* syms) const
 713 {
 714   if (nsyms > this->nsyms_)
 715     return LDPS_NO_SYMS;
 716
 717   if (static_cast<size_t>(nsyms) > this->symbols_.size())
 718     {
 719       // We never decided to include this object. We mark all symbols as
 720       // preempted.
 721       gold_assert(this->symbols_.size() == 0);
 722       for (int i = 0; i < nsyms; i++)
 723         syms[i].resolution = LDPR_PREEMPTED_REG;
 724       return LDPS_OK;
 725     }
 726
 727   for (int i = 0; i < nsyms; i++)
 728     {
 729       ld_plugin_symbol* isym = &syms[i];
 730       Symbol* lsym = this->symbols_[i];
 731       ld_plugin_symbol_resolution res = LDPR_UNKNOWN;
 732
 733       if (lsym->is_undefined())
 734         // The symbol remains undefined.
 735         res = LDPR_UNDEF;
 736       else if (isym->def == LDPK_UNDEF
 737                || isym->def == LDPK_WEAKUNDEF
 738                || isym->def == LDPK_COMMON)
 739         {
 740           // The original symbol was undefined or common.
 741           if (lsym->source() != Symbol::FROM_OBJECT)
 742             res = LDPR_RESOLVED_EXEC;
 743           else if (lsym->object()->pluginobj() == this)
 744             res = (is_visible_from_outside(lsym)
 745                    ? LDPR_PREVAILING_DEF
 746                    : LDPR_PREVAILING_DEF_IRONLY);
 747           else if (lsym->object()->pluginobj() != NULL)
 748             res = LDPR_RESOLVED_IR;
 749           else if (lsym->object()->is_dynamic())
 750             res = LDPR_RESOLVED_DYN;
 751           else
 752             res = LDPR_RESOLVED_EXEC;
 753         }
 754       else
 755         {
 756           // The original symbol was a definition.
 757           if (lsym->source() != Symbol::FROM_OBJECT)
 758             res = LDPR_PREEMPTED_REG;
 759           else if (lsym->object() == static_cast<const Object*>(this))
 760             res = (is_visible_from_outside(lsym)
 761                    ? LDPR_PREVAILING_DEF
 762                    : LDPR_PREVAILING_DEF_IRONLY);
 763           else
 764             res = (lsym->object()->pluginobj() != NULL
 765                    ? LDPR_PREEMPTED_IR
 766                    : LDPR_PREEMPTED_REG);
 767         }
 768       isym->resolution = res;
 769     }
 770   return LDPS_OK;
 771 }
 772
 773 // Return TRUE if the comdat group with key COMDAT_KEY from this object
 774 // should be kept.
 775
 776 bool
 777 Pluginobj::include_comdat_group(std::string comdat_key, Layout* layout)
 778 {
 779   std::pair<Comdat_map::iterator, bool> ins =
 780     this->comdat_map_.insert(std::make_pair(comdat_key, false));
 781
 782   // If this is the first time we've seen this comdat key, ask the
 783   // layout object whether it should be included.
 784   if (ins.second)
 785     ins.first->second = layout->find_or_add_kept_section(comdat_key,
 786                                                          NULL, 0, true,
 787                                                          true, NULL);
 788
 789   return ins.first->second;
 790 }
 791
 792 // Class Sized_pluginobj.
 793
 794 template<int size, bool big_endian>
 795 Sized_pluginobj<size, big_endian>::Sized_pluginobj(
 796     const std::string& name,
 797     Input_file* input_file,
 798     off_t offset,
 799     off_t filesize)
 800   : Pluginobj(name, input_file, offset, filesize)
 801 {
 802 }
 803
 804 // Read the symbols.  Not used for plugin objects.
 805
 806 template<int size, bool big_endian>
 807 void
 808 Sized_pluginobj<size, big_endian>::do_read_symbols(Read_symbols_data*)
 809 {
 810   gold_unreachable();
 811 }
 812
 813 // Lay out the input sections.  Not used for plugin objects.
 814
 815 template<int size, bool big_endian>
 816 void
 817 Sized_pluginobj<size, big_endian>::do_layout(Symbol_table*, Layout*,
 818                                              Read_symbols_data*)
 819 {
 820   gold_unreachable();
 821 }
 822
 823 // Add the symbols to the symbol table.
 824
 825 template<int size, bool big_endian>
 826 void
 827 Sized_pluginobj<size, big_endian>::do_add_symbols(Symbol_table* symtab,
 828                                                   Read_symbols_data*,
 829                                                   Layout* layout)
 830 {
 831   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
 832   unsigned char symbuf[sym_size];
 833   elfcpp::Sym<size, big_endian> sym(symbuf);
 834   elfcpp::Sym_write<size, big_endian> osym(symbuf);
 835
 836   typedef typename elfcpp::Elf_types<size>::Elf_WXword Elf_size_type;
 837
 838   this->symbols_.resize(this->nsyms_);
 839
 840   for (int i = 0; i < this->nsyms_; ++i)
 841     {
 842       const struct ld_plugin_symbol* isym = &this->syms_[i];
 843       const char* name = isym->name;
 844       const char* ver = isym->version;
 845       elfcpp::Elf_Half shndx;
 846       elfcpp::STB bind;
 847       elfcpp::STV vis;
 848
 849       if (name != NULL && name[0] == '\0')
 850         name = NULL;
 851       if (ver != NULL && ver[0] == '\0')
 852         ver = NULL;
 853
 854       switch (isym->def)
 855         {
 856         case LDPK_WEAKDEF:
 857         case LDPK_WEAKUNDEF:
 858           bind = elfcpp::STB_WEAK;
 859           break;
 860         case LDPK_DEF:
 861         case LDPK_UNDEF:
 862         case LDPK_COMMON:
 863         default:
 864           bind = elfcpp::STB_GLOBAL;
 865           break;
 866         }
 867
 868       switch (isym->def)
 869         {
 870         case LDPK_DEF:
 871         case LDPK_WEAKDEF:
 872           shndx = elfcpp::SHN_ABS;
 873           break;
 874         case LDPK_COMMON:
 875           shndx = elfcpp::SHN_COMMON;
 876           break;
 877         case LDPK_UNDEF:
 878         case LDPK_WEAKUNDEF:
 879         default:
 880           shndx = elfcpp::SHN_UNDEF;
 881           break;
 882         }
 883
 884       switch (isym->visibility)
 885         {
 886         case LDPV_PROTECTED:
 887           vis = elfcpp::STV_PROTECTED;
 888           break;
 889         case LDPV_INTERNAL:
 890           vis = elfcpp::STV_INTERNAL;
 891           break;
 892         case LDPV_HIDDEN:
 893           vis = elfcpp::STV_HIDDEN;
 894           break;
 895         case LDPV_DEFAULT:
 896         default:
 897           vis = elfcpp::STV_DEFAULT;
 898           break;
 899         }
 900
 901       if (isym->comdat_key != NULL
 902           && isym->comdat_key[0] != '\0'
 903           && !this->include_comdat_group(isym->comdat_key, layout))
 904         shndx = elfcpp::SHN_UNDEF;
 905
 906       osym.put_st_name(0);
 907       osym.put_st_value(0);
 908       osym.put_st_size(static_cast<Elf_size_type>(isym->size));
 909       osym.put_st_info(bind, elfcpp::STT_NOTYPE);
 910       osym.put_st_other(vis, 0);
 911       osym.put_st_shndx(shndx);
 912
 913       this->symbols_[i] =
 914         symtab->add_from_pluginobj<size, big_endian>(this, name, ver, &sym);
 915     }
 916 }
 917
 918 template<int size, bool big_endian>
 919 Archive::Should_include
 920 Sized_pluginobj<size, big_endian>::do_should_include_member(
 921     Symbol_table* symtab,
 922     Layout* layout,
 923     Read_symbols_data*,
 924     std::string* why)
 925 {
 926   char* tmpbuf = NULL;
 927   size_t tmpbuflen = 0;
 928
 929   for (int i = 0; i < this->nsyms_; ++i)
 930     {
 931       const struct ld_plugin_symbol& sym = this->syms_[i];
 932       const char* name = sym.name;
 933       Symbol* symbol;
 934       Archive::Should_include t = Archive::should_include_member(symtab,
 935                                                                  layout,
 936                                                                  name,
 937                                                                  &symbol, why,
 938                                                                  &tmpbuf,
 939                                                                  &tmpbuflen);
 940       if (t == Archive::SHOULD_INCLUDE_YES)
 941         {
 942           if (tmpbuf != NULL)
 943             free(tmpbuf);
 944           return t;
 945         }
 946     }
 947   if (tmpbuf != NULL)
 948     free(tmpbuf);
 949   return Archive::SHOULD_INCLUDE_UNKNOWN;
 950 }
 951
 952 // Get the size of a section.  Not used for plugin objects.
 953
 954 template<int size, bool big_endian>
 955 uint64_t
 956 Sized_pluginobj<size, big_endian>::do_section_size(unsigned int)
 957 {
 958   gold_unreachable();
 959   return 0;
 960 }
 961
 962 // Get the name of a section.  Not used for plugin objects.
 963
 964 template<int size, bool big_endian>
 965 std::string
 966 Sized_pluginobj<size, big_endian>::do_section_name(unsigned int)
 967 {
 968   gold_unreachable();
 969   return std::string();
 970 }
 971
 972 // Return a view of the contents of a section.  Not used for plugin objects.
 973
 974 template<int size, bool big_endian>
 975 Object::Location
 976 Sized_pluginobj<size, big_endian>::do_section_contents(unsigned int)
 977 {
 978   Location loc(0, 0);
 979
 980   gold_unreachable();
 981   return loc;
 982 }
 983
 984 // Return section flags.  Not used for plugin objects.
 985
 986 template<int size, bool big_endian>
 987 uint64_t
 988 Sized_pluginobj<size, big_endian>::do_section_flags(unsigned int)
 989 {
 990   gold_unreachable();
 991   return 0;
 992 }
 993
 994 // Return section entsize.  Not used for plugin objects.
 995
 996 template<int size, bool big_endian>
 997 uint64_t
 998 Sized_pluginobj<size, big_endian>::do_section_entsize(unsigned int)
 999 {
1000   gold_unreachable();
1001   return 0;
1002 }
1003
1004 // Return section address.  Not used for plugin objects.
1005
1006 template<int size, bool big_endian>
1007 uint64_t
1008 Sized_pluginobj<size, big_endian>::do_section_address(unsigned int)
1009 {
1010   gold_unreachable();
1011   return 0;
1012 }
1013
1014 // Return section type.  Not used for plugin objects.
1015
1016 template<int size, bool big_endian>
1017 unsigned int
1018 Sized_pluginobj<size, big_endian>::do_section_type(unsigned int)
1019 {
1020   gold_unreachable();
1021   return 0;
1022 }
1023
1024 // Return the section link field.  Not used for plugin objects.
1025
1026 template<int size, bool big_endian>
1027 unsigned int
1028 Sized_pluginobj<size, big_endian>::do_section_link(unsigned int)
1029 {
1030   gold_unreachable();
1031   return 0;
1032 }
1033
1034 // Return the section link field.  Not used for plugin objects.
1035
1036 template<int size, bool big_endian>
1037 unsigned int
1038 Sized_pluginobj<size, big_endian>::do_section_info(unsigned int)
1039 {
1040   gold_unreachable();
1041   return 0;
1042 }
1043
1044 // Return the section alignment.  Not used for plugin objects.
1045
1046 template<int size, bool big_endian>
1047 uint64_t
1048 Sized_pluginobj<size, big_endian>::do_section_addralign(unsigned int)
1049 {
1050   gold_unreachable();
1051   return 0;
1052 }
1053
1054 // Return the Xindex structure to use.  Not used for plugin objects.
1055
1056 template<int size, bool big_endian>
1057 Xindex*
1058 Sized_pluginobj<size, big_endian>::do_initialize_xindex()
1059 {
1060   gold_unreachable();
1061   return NULL;
1062 }
1063
1064 // Get symbol counts.  Not used for plugin objects.
1065
1066 template<int size, bool big_endian>
1067 void
1068 Sized_pluginobj<size, big_endian>::do_get_global_symbol_counts(const Symbol_table*,
1069                                                    size_t*, size_t*) const
1070 {
1071   gold_unreachable();
1072 }
1073
1074 // Get symbols.  Not used for plugin objects.
1075
1076 template<int size, bool big_endian>
1077 const Object::Symbols*
1078 Sized_pluginobj<size, big_endian>::do_get_global_symbols() const
1079 {
1080   gold_unreachable();
1081 }
1082
1083 // Class Plugin_finish.  This task runs after all replacement files have
1084 // been added.  For now, it's a placeholder for a possible plugin API
1085 // to allow the plugin to release most of its resources.  The cleanup
1086 // handlers must be called later, because they can remove the temporary
1087 // object files that are needed until the end of the link.
1088
1089 class Plugin_finish : public Task
1090 {
1091  public:
1092   Plugin_finish(Task_token* this_blocker, Task_token* next_blocker)
1093     : this_blocker_(this_blocker), next_blocker_(next_blocker)
1094   { }
1095
1096   ~Plugin_finish()
1097   {
1098     if (this->this_blocker_ != NULL)
1099       delete this->this_blocker_;
1100   }
1101
1102   Task_token*
1103   is_runnable()
1104   {
1105     if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
1106       return this->this_blocker_;
1107     return NULL;
1108   }
1109
1110   void
1111   locks(Task_locker* tl)
1112   { tl->add(this, this->next_blocker_); }
1113
1114   void
1115   run(Workqueue*)
1116   {
1117     // We could call early cleanup handlers here.
1118   }
1119
1120   std::string
1121   get_name() const
1122   { return "Plugin_finish"; }
1123
1124  private:
1125   Task_token* this_blocker_;
1126   Task_token* next_blocker_;
1127 };
1128
1129 // Class Plugin_hook.
1130
1131 Plugin_hook::~Plugin_hook()
1132 {
1133 }
1134
1135 // Return whether a Plugin_hook task is runnable.
1136
1137 Task_token*
1138 Plugin_hook::is_runnable()
1139 {
1140   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
1141     return this->this_blocker_;
1142   return NULL;
1143 }
1144
1145 // Return a Task_locker for a Plugin_hook task.  We don't need any
1146 // locks here.
1147
1148 void
1149 Plugin_hook::locks(Task_locker*)
1150 {
1151 }
1152
1153 // Run the "all symbols read" plugin hook.
1154
1155 void
1156 Plugin_hook::run(Workqueue* workqueue)
1157 {
1158   gold_assert(this->options_.has_plugins());
1159   Symbol* start_sym;
1160   if (parameters->options().entry())
1161     start_sym = this->symtab_->lookup(parameters->options().entry());
1162   else
1163     start_sym = this->symtab_->lookup("_start");
1164   if (start_sym != NULL)
1165     start_sym->set_in_real_elf();
1166
1167   this->options_.plugins()->all_symbols_read(workqueue,
1168                                              this,
1169                                              this->input_objects_,
1170                                              this->symtab_,
1171                                              this->layout_,
1172                                              this->dirpath_,
1173                                              this->mapfile_,
1174                                              &this->this_blocker_);
1175   workqueue->queue_soon(new Plugin_finish(this->this_blocker_,
1176                                           this->next_blocker_));
1177 }
1178
1179 // The C interface routines called by the plugins.
1180
1181 #ifdef ENABLE_PLUGINS
1182
1183 // Register a claim-file handler.
1184
1185 static enum ld_plugin_status
1186 register_claim_file(ld_plugin_claim_file_handler handler)
1187 {
1188   gold_assert(parameters->options().has_plugins());
1189   parameters->options().plugins()->set_claim_file_handler(handler);
1190   return LDPS_OK;
1191 }
1192
1193 // Register an all-symbols-read handler.
1194
1195 static enum ld_plugin_status
1196 register_all_symbols_read(ld_plugin_all_symbols_read_handler handler)
1197 {
1198   gold_assert(parameters->options().has_plugins());
1199   parameters->options().plugins()->set_all_symbols_read_handler(handler);
1200   return LDPS_OK;
1201 }
1202
1203 // Register a cleanup handler.
1204
1205 static enum ld_plugin_status
1206 register_cleanup(ld_plugin_cleanup_handler handler)
1207 {
1208   gold_assert(parameters->options().has_plugins());
1209   parameters->options().plugins()->set_cleanup_handler(handler);
1210   return LDPS_OK;
1211 }
1212
1213 // Add symbols from a plugin-claimed input file.
1214
1215 static enum ld_plugin_status
1216 add_symbols(void* handle, int nsyms, const ld_plugin_symbol* syms)
1217 {
1218   gold_assert(parameters->options().has_plugins());
1219   Pluginobj* obj = parameters->options().plugins()->make_plugin_object(
1220       static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle)));
1221   if (obj == NULL)
1222     return LDPS_ERR;
1223   obj->store_incoming_symbols(nsyms, syms);
1224   return LDPS_OK;
1225 }
1226
1227 // Get the input file information with an open (possibly re-opened)
1228 // file descriptor.
1229
1230 static enum ld_plugin_status
1231 get_input_file(const void* handle, struct ld_plugin_input_file* file)
1232 {
1233   gold_assert(parameters->options().has_plugins());
1234   unsigned int obj_index =
1235       static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle));
1236   return parameters->options().plugins()->get_input_file(obj_index, file);
1237 }
1238
1239 // Release the input file.
1240
1241 static enum ld_plugin_status
1242 release_input_file(const void* handle)
1243 {
1244   gold_assert(parameters->options().has_plugins());
1245   unsigned int obj_index =
1246       static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle));
1247   return parameters->options().plugins()->release_input_file(obj_index);
1248 }
1249
1250 // Get the symbol resolution info for a plugin-claimed input file.
1251
1252 static enum ld_plugin_status
1253 get_symbols(const void* handle, int nsyms, ld_plugin_symbol* syms)
1254 {
1255   gold_assert(parameters->options().has_plugins());
1256   Pluginobj* obj = parameters->options().plugins()->object(
1257       static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle)));
1258   if (obj == NULL)
1259     return LDPS_ERR;
1260   return obj->get_symbol_resolution_info(nsyms, syms);
1261 }
1262
1263 // Add a new (real) input file generated by a plugin.
1264
1265 static enum ld_plugin_status
1266 add_input_file(const char* pathname)
1267 {
1268   gold_assert(parameters->options().has_plugins());
1269   return parameters->options().plugins()->add_input_file(pathname, false);
1270 }
1271
1272 // Add a new (real) library required by a plugin.
1273
1274 static enum ld_plugin_status
1275 add_input_library(const char* pathname)
1276 {
1277   gold_assert(parameters->options().has_plugins());
1278   return parameters->options().plugins()->add_input_file(pathname, true);
1279 }
1280
1281 // Set the extra library path to be used by libraries added via
1282 // add_input_library
1283
1284 static enum ld_plugin_status
1285 set_extra_library_path(const char* path)
1286 {
1287   gold_assert(parameters->options().has_plugins());
1288   return parameters->options().plugins()->set_extra_library_path(path);
1289 }
1290
1291 // Issue a diagnostic message from a plugin.
1292
1293 static enum ld_plugin_status
1294 message(int level, const char* format, ...)
1295 {
1296   va_list args;
1297   va_start(args, format);
1298
1299   switch (level)
1300     {
1301     case LDPL_INFO:
1302       parameters->errors()->info(format, args);
1303       break;
1304     case LDPL_WARNING:
1305       parameters->errors()->warning(format, args);
1306       break;
1307     case LDPL_ERROR:
1308     default:
1309       parameters->errors()->error(format, args);
1310       break;
1311     case LDPL_FATAL:
1312       parameters->errors()->fatal(format, args);
1313       break;
1314     }
1315
1316   va_end(args);
1317   return LDPS_OK;
1318 }
1319
1320 #endif // ENABLE_PLUGINS
1321
1322 // Allocate a Pluginobj object of the appropriate size and endianness.
1323
1324 static Pluginobj*
1325 make_sized_plugin_object(Input_file* input_file, off_t offset, off_t filesize)
1326 {
1327   Pluginobj* obj = NULL;
1328
1329   parameters_force_valid_target();
1330   const Target& target(parameters->target());
1331
1332   if (target.get_size() == 32)
1333     {
1334       if (target.is_big_endian())
1335 #ifdef HAVE_TARGET_32_BIG
1336         obj = new Sized_pluginobj<32, true>(input_file->filename(),
1337                                             input_file, offset, filesize);
1338 #else
1339         gold_error(_("%s: not configured to support "
1340                      "32-bit big-endian object"),
1341                    input_file->filename().c_str());
1342 #endif
1343       else
1344 #ifdef HAVE_TARGET_32_LITTLE
1345         obj = new Sized_pluginobj<32, false>(input_file->filename(),
1346                                              input_file, offset, filesize);
1347 #else
1348         gold_error(_("%s: not configured to support "
1349                      "32-bit little-endian object"),
1350                    input_file->filename().c_str());
1351 #endif
1352     }
1353   else if (target.get_size() == 64)
1354     {
1355       if (target.is_big_endian())
1356 #ifdef HAVE_TARGET_64_BIG
1357         obj = new Sized_pluginobj<64, true>(input_file->filename(),
1358                                             input_file, offset, filesize);
1359 #else
1360         gold_error(_("%s: not configured to support "
1361                      "64-bit big-endian object"),
1362                    input_file->filename().c_str());
1363 #endif
1364       else
1365 #ifdef HAVE_TARGET_64_LITTLE
1366         obj = new Sized_pluginobj<64, false>(input_file->filename(),
1367                                              input_file, offset, filesize);
1368 #else
1369         gold_error(_("%s: not configured to support "
1370                      "64-bit little-endian object"),
1371                    input_file->filename().c_str());
1372 #endif
1373     }
1374
1375   gold_assert(obj != NULL);
1376   return obj;
1377 }
1378
1379 } // End namespace gold.