gold/plugin.h

   1 // plugin.h -- plugin manager for gold      -*- C++ -*-
   2
   3 // Copyright (C) 2008-2014 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 #ifndef GOLD_PLUGIN_H
  24 #define GOLD_PLUGIN_H
  25
  26 #include <list>
  27 #include <string>
  28
  29 #include "object.h"
  30 #include "plugin-api.h"
  31 #include "workqueue.h"
  32
  33 namespace gold
  34 {
  35
  36 class General_options;
  37 class Input_file;
  38 class Input_objects;
  39 class Archive;
  40 class Input_group;
  41 class Symbol;
  42 class Symbol_table;
  43 class Layout;
  44 class Dirsearch;
  45 class Mapfile;
  46 class Task;
  47 class Task_token;
  48 class Pluginobj;
  49 class Plugin_rescan;
  50
  51 // This class represents a single plugin library.
  52
  53 class Plugin
  54 {
  55  public:
  56   Plugin(const char* filename)
  57     : handle_(NULL),
  58       filename_(filename),
  59       args_(),
  60       claim_file_handler_(NULL),
  61       all_symbols_read_handler_(NULL),
  62       cleanup_handler_(NULL),
  63       cleanup_done_(false)
  64   { }
  65
  66   ~Plugin()
  67   { }
  68
  69   // Load the library and call its entry point.
  70   void
  71   load();
  72
  73   // Call the claim-file handler.
  74   bool
  75   claim_file(struct ld_plugin_input_file* plugin_input_file);
  76
  77   // Call the all-symbols-read handler.
  78   void
  79   all_symbols_read();
  80
  81   // Call the cleanup handler.
  82   void
  83   cleanup();
  84
  85   // Register a claim-file handler.
  86   void
  87   set_claim_file_handler(ld_plugin_claim_file_handler handler)
  88   { this->claim_file_handler_ = handler; }
  89
  90   // Register an all-symbols-read handler.
  91   void
  92   set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)
  93   { this->all_symbols_read_handler_ = handler; }
  94
  95   // Register a claim-file handler.
  96   void
  97   set_cleanup_handler(ld_plugin_cleanup_handler handler)
  98   { this->cleanup_handler_ = handler; }
  99
 100   // Add an argument
 101   void
 102   add_option(const char* arg)
 103   {
 104     this->args_.push_back(arg);
 105   }
 106
 107  private:
 108   Plugin(const Plugin&);
 109   Plugin& operator=(const Plugin&);
 110
 111   // The shared library handle returned by dlopen.
 112   void* handle_;
 113   // The argument string given to --plugin.
 114   std::string filename_;
 115   // The list of argument string given to --plugin-opt.
 116   std::vector<std::string> args_;
 117   // The plugin's event handlers.
 118   ld_plugin_claim_file_handler claim_file_handler_;
 119   ld_plugin_all_symbols_read_handler all_symbols_read_handler_;
 120   ld_plugin_cleanup_handler cleanup_handler_;
 121   // TRUE if the cleanup handlers have been called.
 122   bool cleanup_done_;
 123 };
 124
 125 // A manager class for plugins.
 126
 127 class Plugin_manager
 128 {
 129  public:
 130   Plugin_manager(const General_options& options)
 131     : plugins_(), objects_(), deferred_layout_objects_(), input_file_(NULL),
 132       plugin_input_file_(), rescannable_(), undefined_symbols_(),
 133       any_claimed_(false), in_replacement_phase_(false), any_added_(false),
 134       in_claim_file_handler_(false),
 135       options_(options), workqueue_(NULL), task_(NULL), input_objects_(NULL),
 136       symtab_(NULL), layout_(NULL), dirpath_(NULL), mapfile_(NULL),
 137       this_blocker_(NULL), extra_search_path_()
 138   { this->current_ = plugins_.end(); }
 139
 140   ~Plugin_manager();
 141
 142   // Add a plugin library.
 143   void
 144   add_plugin(const char* filename)
 145   { this->plugins_.push_back(new Plugin(filename)); }
 146
 147   // Add an argument to the current plugin.
 148   void
 149   add_plugin_option(const char* opt)
 150   {
 151     Plugin* last = this->plugins_.back();
 152     last->add_option(opt);
 153   }
 154
 155   // Load all plugin libraries.
 156   void
 157   load_plugins(Layout* layout);
 158
 159   // Call the plugin claim-file handlers in turn to see if any claim the file.
 160   Pluginobj*
 161   claim_file(Input_file* input_file, off_t offset, off_t filesize,
 162              Object* elf_object);
 163
 164   // Get the object associated with the handle and check if it is an elf object.
 165   // If it is not a Pluginobj, it is an elf object.
 166   Object*
 167   get_elf_object(const void* handle);
 168
 169   // True if the claim_file handler of the plugins is being called.
 170   bool
 171   in_claim_file_handler()
 172   { return in_claim_file_handler_; }
 173
 174   // Let the plugin manager save an archive for later rescanning.
 175   // This takes ownership of the Archive pointer.
 176   void
 177   save_archive(Archive*);
 178
 179   // Let the plugin manager save an input group for later rescanning.
 180   // This takes ownership of the Input_group pointer.
 181   void
 182   save_input_group(Input_group*);
 183
 184   // Call the all-symbols-read handlers.
 185   void
 186   all_symbols_read(Workqueue* workqueue, Task* task,
 187                    Input_objects* input_objects, Symbol_table* symtab,
 188                    Dirsearch* dirpath, Mapfile* mapfile,
 189                    Task_token** last_blocker);
 190
 191   // Tell the plugin manager that we've a new undefined symbol which
 192   // may require rescanning.
 193   void
 194   new_undefined_symbol(Symbol*);
 195
 196   // Run deferred layout.
 197   void
 198   layout_deferred_objects();
 199
 200   // Call the cleanup handlers.
 201   void
 202   cleanup();
 203
 204   // Register a claim-file handler.
 205   void
 206   set_claim_file_handler(ld_plugin_claim_file_handler handler)
 207   {
 208     gold_assert(this->current_ != plugins_.end());
 209     (*this->current_)->set_claim_file_handler(handler);
 210   }
 211
 212   // Register an all-symbols-read handler.
 213   void
 214   set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)
 215   {
 216     gold_assert(this->current_ != plugins_.end());
 217     (*this->current_)->set_all_symbols_read_handler(handler);
 218   }
 219
 220   // Register a claim-file handler.
 221   void
 222   set_cleanup_handler(ld_plugin_cleanup_handler handler)
 223   {
 224     gold_assert(this->current_ != plugins_.end());
 225     (*this->current_)->set_cleanup_handler(handler);
 226   }
 227
 228   // Make a new Pluginobj object.  This is called when the plugin calls
 229   // the add_symbols API.
 230   Pluginobj*
 231   make_plugin_object(unsigned int handle);
 232
 233   // Return the object associated with the given HANDLE.
 234   Object*
 235   object(unsigned int handle) const
 236   {
 237     if (handle >= this->objects_.size())
 238       return NULL;
 239     return this->objects_[handle];
 240   }
 241
 242   // Return TRUE if any input files have been claimed by a plugin
 243   // and we are still in the initial input phase.
 244   bool
 245   should_defer_layout() const
 246   { return this->any_claimed_ && !this->in_replacement_phase_; }
 247
 248   // Add a regular object to the deferred layout list.  These are
 249   // objects whose layout has been deferred until after the
 250   // replacement files have arrived.
 251   void
 252   add_deferred_layout_object(Relobj* obj)
 253   { this->deferred_layout_objects_.push_back(obj); }
 254
 255   // Get input file information with an open (possibly re-opened)
 256   // file descriptor.
 257   ld_plugin_status
 258   get_input_file(unsigned int handle, struct ld_plugin_input_file* file);
 259
 260   ld_plugin_status
 261   get_view(unsigned int handle, const void **viewp);
 262
 263   // Release an input file.
 264   ld_plugin_status
 265   release_input_file(unsigned int handle);
 266
 267   // Add a new input file.
 268   ld_plugin_status
 269   add_input_file(const char* pathname, bool is_lib);
 270
 271   // Set the extra library path.
 272   ld_plugin_status
 273   set_extra_library_path(const char* path);
 274
 275   // Return TRUE if we are in the replacement phase.
 276   bool
 277   in_replacement_phase() const
 278   { return this->in_replacement_phase_; }
 279
 280   Input_objects*
 281   input_objects() const
 282   { return this->input_objects_; }
 283
 284   Layout*
 285   layout()
 286   { return this->layout_; }
 287
 288  private:
 289   Plugin_manager(const Plugin_manager&);
 290   Plugin_manager& operator=(const Plugin_manager&);
 291
 292   // Plugin_rescan is a Task which calls the private rescan method.
 293   friend class Plugin_rescan;
 294
 295   // An archive or input group which may have to be rescanned if a
 296   // plugin adds a new file.
 297   struct Rescannable
 298   {
 299     bool is_archive;
 300     union
 301     {
 302       Archive* archive;
 303       Input_group* input_group;
 304     } u;
 305
 306     Rescannable(Archive* archive)
 307       : is_archive(true)
 308     { this->u.archive = archive; }
 309
 310     Rescannable(Input_group* input_group)
 311       : is_archive(false)
 312     { this->u.input_group = input_group; }
 313   };
 314
 315   typedef std::list<Plugin*> Plugin_list;
 316   typedef std::vector<Object*> Object_list;
 317   typedef std::vector<Relobj*> Deferred_layout_list;
 318   typedef std::vector<Rescannable> Rescannable_list;
 319   typedef std::vector<Symbol*> Undefined_symbol_list;
 320
 321   // Rescan archives for undefined symbols.
 322   void
 323   rescan(Task*);
 324
 325   // See whether the rescannable at index I defines SYM.
 326   bool
 327   rescannable_defines(size_t i, Symbol* sym);
 328
 329   // The list of plugin libraries.
 330   Plugin_list plugins_;
 331   // A pointer to the current plugin.  Used while loading plugins.
 332   Plugin_list::iterator current_;
 333
 334   // The list of plugin objects.  The index of an item in this list
 335   // serves as the "handle" that we pass to the plugins.
 336   Object_list objects_;
 337
 338   // The list of regular objects whose layout has been deferred.
 339   Deferred_layout_list deferred_layout_objects_;
 340
 341   // The file currently up for claim by the plugins.
 342   Input_file* input_file_;
 343   struct ld_plugin_input_file plugin_input_file_;
 344
 345   // A list of archives and input groups being saved for possible
 346   // later rescanning.
 347   Rescannable_list rescannable_;
 348
 349   // A list of undefined symbols found in added files.
 350   Undefined_symbol_list undefined_symbols_;
 351
 352   // Whether any input files have been claimed by a plugin.
 353   bool any_claimed_;
 354
 355   // Set to true after the all symbols read event; indicates that we
 356   // are processing replacement files whose symbols should replace the
 357   // placeholder symbols from the Pluginobj objects.
 358   bool in_replacement_phase_;
 359
 360   // Whether any input files or libraries were added by a plugin.
 361   bool any_added_;
 362
 363   // Set to true when the claim_file handler of a plugin is called.
 364   bool in_claim_file_handler_;
 365
 366   const General_options& options_;
 367   Workqueue* workqueue_;
 368   Task* task_;
 369   Input_objects* input_objects_;
 370   Symbol_table* symtab_;
 371   Layout* layout_;
 372   Dirsearch* dirpath_;
 373   Mapfile* mapfile_;
 374   Task_token* this_blocker_;
 375
 376   // An extra directory to seach for the libraries passed by
 377   // add_input_library.
 378   std::string extra_search_path_;
 379 };
 380
 381
 382 // An object file claimed by a plugin.  This is an abstract base class.
 383 // The implementation is the template class Sized_pluginobj.
 384
 385 class Pluginobj : public Object
 386 {
 387  public:
 388
 389   typedef std::vector<Symbol*> Symbols;
 390
 391   Pluginobj(const std::string& name, Input_file* input_file, off_t offset,
 392             off_t filesize);
 393
 394   // Fill in the symbol resolution status for the given plugin symbols.
 395   ld_plugin_status
 396   get_symbol_resolution_info(int nsyms,
 397                              ld_plugin_symbol* syms,
 398                              int version) const;
 399
 400   // Store the incoming symbols from the plugin for later processing.
 401   void
 402   store_incoming_symbols(int nsyms, const struct ld_plugin_symbol* syms)
 403   {
 404     this->nsyms_ = nsyms;
 405     this->syms_ = syms;
 406   }
 407
 408   // Return TRUE if the comdat group with key COMDAT_KEY from this object
 409   // should be kept.
 410   bool
 411   include_comdat_group(std::string comdat_key, Layout* layout);
 412
 413   // Return the filename.
 414   const std::string&
 415   filename() const
 416   { return this->input_file()->filename(); }
 417
 418   // Return the file descriptor.
 419   int
 420   descriptor()
 421   { return this->input_file()->file().descriptor(); }
 422
 423   // Return the size of the file or archive member.
 424   off_t
 425   filesize()
 426   { return this->filesize_; }
 427
 428  protected:
 429   // Return TRUE if this is an object claimed by a plugin.
 430   virtual Pluginobj*
 431   do_pluginobj()
 432   { return this; }
 433
 434   // The number of symbols provided by the plugin.
 435   int nsyms_;
 436
 437   // The symbols provided by the plugin.
 438   const struct ld_plugin_symbol* syms_;
 439
 440   // The entries in the symbol table for the external symbols.
 441   Symbols symbols_;
 442
 443  private:
 444   // Size of the file (or archive member).
 445   off_t filesize_;
 446   // Map a comdat key symbol to a boolean indicating whether the comdat
 447   // group in this object with that key should be kept.
 448   typedef Unordered_map<std::string, bool> Comdat_map;
 449   Comdat_map comdat_map_;
 450 };
 451
 452 // A plugin object, size-specific version.
 453
 454 template<int size, bool big_endian>
 455 class Sized_pluginobj : public Pluginobj
 456 {
 457  public:
 458   Sized_pluginobj(const std::string& name, Input_file* input_file,
 459                   off_t offset, off_t filesize);
 460
 461   // Read the symbols.
 462   void
 463   do_read_symbols(Read_symbols_data*);
 464
 465   // Lay out the input sections.
 466   void
 467   do_layout(Symbol_table*, Layout*, Read_symbols_data*);
 468
 469   // Add the symbols to the symbol table.
 470   void
 471   do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);
 472
 473   Archive::Should_include
 474   do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
 475                            std::string* why);
 476
 477   // Iterate over global symbols, calling a visitor class V for each.
 478   void
 479   do_for_all_global_symbols(Read_symbols_data* sd,
 480                             Library_base::Symbol_visitor_base* v);
 481
 482   // Iterate over local symbols, calling a visitor class V for each GOT offset
 483   // associated with a local symbol.
 484   void
 485   do_for_all_local_got_entries(Got_offset_list::Visitor* v) const;
 486
 487   // Get the size of a section.
 488   uint64_t
 489   do_section_size(unsigned int shndx);
 490
 491   // Get the name of a section.
 492   std::string
 493   do_section_name(unsigned int shndx) const;
 494
 495   // Return a view of the contents of a section.
 496   const unsigned char*
 497   do_section_contents(unsigned int shndx, section_size_type* plen,
 498                       bool cache);
 499
 500   // Return section flags.
 501   uint64_t
 502   do_section_flags(unsigned int shndx);
 503
 504   // Return section entsize.
 505   uint64_t
 506   do_section_entsize(unsigned int shndx);
 507
 508   // Return section address.
 509   uint64_t
 510   do_section_address(unsigned int shndx);
 511
 512   // Return section type.
 513   unsigned int
 514   do_section_type(unsigned int shndx);
 515
 516   // Return the section link field.
 517   unsigned int
 518   do_section_link(unsigned int shndx);
 519
 520   // Return the section link field.
 521   unsigned int
 522   do_section_info(unsigned int shndx);
 523
 524   // Return the section alignment.
 525   uint64_t
 526   do_section_addralign(unsigned int shndx);
 527
 528   // Return the Xindex structure to use.
 529   Xindex*
 530   do_initialize_xindex();
 531
 532   // Get symbol counts.
 533   void
 534   do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
 535
 536   // Get global symbols.
 537   const Symbols*
 538   do_get_global_symbols() const;
 539
 540   // Add placeholder symbols from a claimed file.
 541   ld_plugin_status
 542   add_symbols_from_plugin(int nsyms, const ld_plugin_symbol* syms);
 543
 544  protected:
 545
 546  private:
 547 };
 548
 549 // This Task handles handles the "all symbols read" event hook.
 550 // The plugin may add additional input files at this time, which must
 551 // be queued for reading.
 552
 553 class Plugin_hook : public Task
 554 {
 555  public:
 556   Plugin_hook(const General_options& options, Input_objects* input_objects,
 557               Symbol_table* symtab, Layout* /*layout*/, Dirsearch* dirpath,
 558               Mapfile* mapfile, Task_token* this_blocker,
 559               Task_token* next_blocker)
 560     : options_(options), input_objects_(input_objects), symtab_(symtab),
 561       dirpath_(dirpath), mapfile_(mapfile),
 562       this_blocker_(this_blocker), next_blocker_(next_blocker)
 563   { }
 564
 565   ~Plugin_hook();
 566
 567   // The standard Task methods.
 568
 569   Task_token*
 570   is_runnable();
 571
 572   void
 573   locks(Task_locker*);
 574
 575   void
 576   run(Workqueue*);
 577
 578   std::string
 579   get_name() const
 580   { return "Plugin_hook"; }
 581
 582  private:
 583   const General_options& options_;
 584   Input_objects* input_objects_;
 585   Symbol_table* symtab_;
 586   Dirsearch* dirpath_;
 587   Mapfile* mapfile_;
 588   Task_token* this_blocker_;
 589   Task_token* next_blocker_;
 590 };
 591
 592 } // End namespace gold.
 593
 594 #endif // !defined(GOLD_PLUGIN_H)