gold/plugin.h

   1 // plugin.h -- 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 #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       options_(options), workqueue_(NULL), task_(NULL), input_objects_(NULL),
 135       symtab_(NULL), layout_(NULL), dirpath_(NULL), mapfile_(NULL),
 136       this_blocker_(NULL), extra_search_path_()
 137   { this->current_ = plugins_.end(); }
 138
 139   ~Plugin_manager();
 140
 141   // Add a plugin library.
 142   void
 143   add_plugin(const char* filename)
 144   { this->plugins_.push_back(new Plugin(filename)); }
 145
 146   // Add an argument to the current plugin.
 147   void
 148   add_plugin_option(const char* opt)
 149   {
 150     Plugin* last = this->plugins_.back();
 151     last->add_option(opt);
 152   }
 153
 154   // Load all plugin libraries.
 155   void
 156   load_plugins();
 157
 158   // Call the plugin claim-file handlers in turn to see if any claim the file.
 159   Pluginobj*
 160   claim_file(Input_file* input_file, off_t offset, off_t filesize);
 161
 162   // Let the plugin manager save an archive for later rescanning.
 163   // This takes ownership of the Archive pointer.
 164   void
 165   save_archive(Archive*);
 166
 167   // Let the plugin manager save an input group for later rescanning.
 168   // This takes ownership of the Input_group pointer.
 169   void
 170   save_input_group(Input_group*);
 171
 172   // Call the all-symbols-read handlers.
 173   void
 174   all_symbols_read(Workqueue* workqueue, Task* task,
 175                    Input_objects* input_objects, Symbol_table* symtab,
 176                    Layout* layout, Dirsearch* dirpath, Mapfile* mapfile,
 177                    Task_token** last_blocker);
 178
 179   // Tell the plugin manager that we've a new undefined symbol which
 180   // may require rescanning.
 181   void
 182   new_undefined_symbol(Symbol*);
 183
 184   // Run deferred layout.
 185   void
 186   layout_deferred_objects();
 187
 188   // Call the cleanup handlers.
 189   void
 190   cleanup();
 191
 192   // Register a claim-file handler.
 193   void
 194   set_claim_file_handler(ld_plugin_claim_file_handler handler)
 195   {
 196     gold_assert(this->current_ != plugins_.end());
 197     (*this->current_)->set_claim_file_handler(handler);
 198   }
 199
 200   // Register an all-symbols-read handler.
 201   void
 202   set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)
 203   {
 204     gold_assert(this->current_ != plugins_.end());
 205     (*this->current_)->set_all_symbols_read_handler(handler);
 206   }
 207
 208   // Register a claim-file handler.
 209   void
 210   set_cleanup_handler(ld_plugin_cleanup_handler handler)
 211   {
 212     gold_assert(this->current_ != plugins_.end());
 213     (*this->current_)->set_cleanup_handler(handler);
 214   }
 215
 216   // Make a new Pluginobj object.  This is called when the plugin calls
 217   // the add_symbols API.
 218   Pluginobj*
 219   make_plugin_object(unsigned int handle);
 220
 221   // Return the Pluginobj associated with the given HANDLE.
 222   Pluginobj*
 223   object(unsigned int handle) const
 224   {
 225     if (handle >= this->objects_.size())
 226       return NULL;
 227     return this->objects_[handle];
 228   }
 229
 230   // Return TRUE if any input files have been claimed by a plugin
 231   // and we are still in the initial input phase.
 232   bool
 233   should_defer_layout() const
 234   { return !this->objects_.empty() && !this->in_replacement_phase_; }
 235
 236   // Add a regular object to the deferred layout list.  These are
 237   // objects whose layout has been deferred until after the
 238   // replacement files have arrived.
 239   void
 240   add_deferred_layout_object(Relobj* obj)
 241   { this->deferred_layout_objects_.push_back(obj); }
 242
 243   // Get input file information with an open (possibly re-opened)
 244   // file descriptor.
 245   ld_plugin_status
 246   get_input_file(unsigned int handle, struct ld_plugin_input_file* file);
 247
 248   // Release an input file.
 249   ld_plugin_status
 250   release_input_file(unsigned int handle);
 251
 252   // Add a new input file.
 253   ld_plugin_status
 254   add_input_file(const char* pathname, bool is_lib);
 255
 256   // Set the extra library path.
 257   ld_plugin_status
 258   set_extra_library_path(const char* path);
 259
 260   // Return TRUE if we are in the replacement phase.
 261   bool
 262   in_replacement_phase() const
 263   { return this->in_replacement_phase_; }
 264
 265  private:
 266   Plugin_manager(const Plugin_manager&);
 267   Plugin_manager& operator=(const Plugin_manager&);
 268
 269   // Plugin_rescan is a Task which calls the private rescan method.
 270   friend class Plugin_rescan;
 271
 272   // An archive or input group which may have to be rescanned if a
 273   // plugin adds a new file.
 274   struct Rescannable
 275   {
 276     bool is_archive;
 277     union
 278     {
 279       Archive* archive;
 280       Input_group* input_group;
 281     } u;
 282
 283     Rescannable(Archive* archive)
 284       : is_archive(true)
 285     { this->u.archive = archive; }
 286
 287     Rescannable(Input_group* input_group)
 288       : is_archive(false)
 289     { this->u.input_group = input_group; }
 290   };
 291
 292   typedef std::list<Plugin*> Plugin_list;
 293   typedef std::vector<Pluginobj*> Object_list;
 294   typedef std::vector<Relobj*> Deferred_layout_list;
 295   typedef std::vector<Rescannable> Rescannable_list;
 296   typedef std::vector<Symbol*> Undefined_symbol_list;
 297
 298   // Rescan archives for undefined symbols.
 299   void
 300   rescan(Task*);
 301
 302   // See whether the rescannable at index I defines SYM.
 303   bool
 304   rescannable_defines(size_t i, Symbol* sym);
 305
 306   // The list of plugin libraries.
 307   Plugin_list plugins_;
 308   // A pointer to the current plugin.  Used while loading plugins.
 309   Plugin_list::iterator current_;
 310
 311   // The list of plugin objects.  The index of an item in this list
 312   // serves as the "handle" that we pass to the plugins.
 313   Object_list objects_;
 314
 315   // The list of regular objects whose layout has been deferred.
 316   Deferred_layout_list deferred_layout_objects_;
 317
 318   // The file currently up for claim by the plugins.
 319   Input_file* input_file_;
 320   struct ld_plugin_input_file plugin_input_file_;
 321
 322   // A list of archives and input groups being saved for possible
 323   // later rescanning.
 324   Rescannable_list rescannable_;
 325
 326   // A list of undefined symbols found in added files.
 327   Undefined_symbol_list undefined_symbols_;
 328
 329   // Whether any input files have been claimed by a plugin.
 330   bool any_claimed_;
 331
 332   // Set to true after the all symbols read event; indicates that we
 333   // are processing replacement files whose symbols should replace the
 334   // placeholder symbols from the Pluginobj objects.
 335   bool in_replacement_phase_;
 336
 337   // Whether any input files or libraries were added by a plugin.
 338   bool any_added_;
 339
 340   const General_options& options_;
 341   Workqueue* workqueue_;
 342   Task* task_;
 343   Input_objects* input_objects_;
 344   Symbol_table* symtab_;
 345   Layout* layout_;
 346   Dirsearch* dirpath_;
 347   Mapfile* mapfile_;
 348   Task_token* this_blocker_;
 349
 350   // An extra directory to seach for the libraries passed by
 351   // add_input_library.
 352   std::string extra_search_path_;
 353 };
 354
 355
 356 // An object file claimed by a plugin.  This is an abstract base class.
 357 // The implementation is the template class Sized_pluginobj.
 358
 359 class Pluginobj : public Object
 360 {
 361  public:
 362
 363   typedef std::vector<Symbol*> Symbols;
 364
 365   Pluginobj(const std::string& name, Input_file* input_file, off_t offset,
 366             off_t filesize);
 367
 368   // Fill in the symbol resolution status for the given plugin symbols.
 369   ld_plugin_status
 370   get_symbol_resolution_info(int nsyms, ld_plugin_symbol* syms) const;
 371
 372   // Store the incoming symbols from the plugin for later processing.
 373   void
 374   store_incoming_symbols(int nsyms, const struct ld_plugin_symbol* syms)
 375   {
 376     this->nsyms_ = nsyms;
 377     this->syms_ = syms;
 378   }
 379
 380   // Return TRUE if the comdat group with key COMDAT_KEY from this object
 381   // should be kept.
 382   bool
 383   include_comdat_group(std::string comdat_key, Layout* layout);
 384
 385   // Return the filename.
 386   const std::string&
 387   filename() const
 388   { return this->input_file()->filename(); }
 389
 390   // Return the file descriptor.
 391   int
 392   descriptor()
 393   { return this->input_file()->file().descriptor(); }
 394
 395   // Return the size of the file or archive member.
 396   off_t
 397   filesize()
 398   { return this->filesize_; }
 399
 400  protected:
 401   // Return TRUE if this is an object claimed by a plugin.
 402   virtual Pluginobj*
 403   do_pluginobj()
 404   { return this; }
 405
 406   // The number of symbols provided by the plugin.
 407   int nsyms_;
 408
 409   // The symbols provided by the plugin.
 410   const struct ld_plugin_symbol* syms_;
 411
 412   // The entries in the symbol table for the external symbols.
 413   Symbols symbols_;
 414
 415  private:
 416   // Size of the file (or archive member).
 417   off_t filesize_;
 418   // Map a comdat key symbol to a boolean indicating whether the comdat
 419   // group in this object with that key should be kept.
 420   typedef Unordered_map<std::string, bool> Comdat_map;
 421   Comdat_map comdat_map_;
 422 };
 423
 424 // A plugin object, size-specific version.
 425
 426 template<int size, bool big_endian>
 427 class Sized_pluginobj : public Pluginobj
 428 {
 429  public:
 430   Sized_pluginobj(const std::string& name, Input_file* input_file,
 431                   off_t offset, off_t filesize);
 432
 433   // Read the symbols.
 434   void
 435   do_read_symbols(Read_symbols_data*);
 436
 437   // Lay out the input sections.
 438   void
 439   do_layout(Symbol_table*, Layout*, Read_symbols_data*);
 440
 441   // Add the symbols to the symbol table.
 442   void
 443   do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);
 444
 445   Archive::Should_include
 446   do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
 447                            std::string* why);
 448
 449   // Get the size of a section.
 450   uint64_t
 451   do_section_size(unsigned int shndx);
 452
 453   // Get the name of a section.
 454   std::string
 455   do_section_name(unsigned int shndx);
 456
 457   // Return a view of the contents of a section.
 458   Object::Location
 459   do_section_contents(unsigned int shndx);
 460
 461   // Return section flags.
 462   uint64_t
 463   do_section_flags(unsigned int shndx);
 464
 465   // Return section entsize.
 466   uint64_t
 467   do_section_entsize(unsigned int shndx);
 468
 469   // Return section address.
 470   uint64_t
 471   do_section_address(unsigned int shndx);
 472
 473   // Return section type.
 474   unsigned int
 475   do_section_type(unsigned int shndx);
 476
 477   // Return the section link field.
 478   unsigned int
 479   do_section_link(unsigned int shndx);
 480
 481   // Return the section link field.
 482   unsigned int
 483   do_section_info(unsigned int shndx);
 484
 485   // Return the section alignment.
 486   uint64_t
 487   do_section_addralign(unsigned int shndx);
 488
 489   // Return the Xindex structure to use.
 490   Xindex*
 491   do_initialize_xindex();
 492
 493   // Get symbol counts.
 494   void
 495   do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
 496
 497   // Get global symbols.
 498   const Symbols*
 499   do_get_global_symbols() const;
 500
 501   // Add placeholder symbols from a claimed file.
 502   ld_plugin_status
 503   add_symbols_from_plugin(int nsyms, const ld_plugin_symbol* syms);
 504
 505  protected:
 506
 507  private:
 508 };
 509
 510 // This Task handles handles the "all symbols read" event hook.
 511 // The plugin may add additional input files at this time, which must
 512 // be queued for reading.
 513
 514 class Plugin_hook : public Task
 515 {
 516  public:
 517   Plugin_hook(const General_options& options, Input_objects* input_objects,
 518               Symbol_table* symtab, Layout* layout, Dirsearch* dirpath,
 519               Mapfile* mapfile, Task_token* this_blocker,
 520               Task_token* next_blocker)
 521     : options_(options), input_objects_(input_objects), symtab_(symtab),
 522       layout_(layout), dirpath_(dirpath), mapfile_(mapfile),
 523       this_blocker_(this_blocker), next_blocker_(next_blocker)
 524   { }
 525
 526   ~Plugin_hook();
 527
 528   // The standard Task methods.
 529
 530   Task_token*
 531   is_runnable();
 532
 533   void
 534   locks(Task_locker*);
 535
 536   void
 537   run(Workqueue*);
 538
 539   std::string
 540   get_name() const
 541   { return "Plugin_hook"; }
 542
 543  private:
 544   const General_options& options_;
 545   Input_objects* input_objects_;
 546   Symbol_table* symtab_;
 547   Layout* layout_;
 548   Dirsearch* dirpath_;
 549   Mapfile* mapfile_;
 550   Task_token* this_blocker_;
 551   Task_token* next_blocker_;
 552 };
 553
 554 } // End namespace gold.
 555
 556 #endif // !defined(GOLD_PLUGIN_H)