gold/plugin.h

   1 // plugin.h -- plugin manager for gold      -*- C++ -*-
   2
   3 // Copyright 2008 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 Symbol_table;
  40 class Layout;
  41 class Dirsearch;
  42 class Mapfile;
  43 class Task_token;
  44 class Pluginobj;
  45
  46 // This class represents a single plugin library.
  47
  48 class Plugin
  49 {
  50  public:
  51   Plugin(const char* filename)
  52     : handle_(NULL),
  53       filename_(filename),
  54       args_(),
  55       claim_file_handler_(NULL),
  56       all_symbols_read_handler_(NULL),
  57       cleanup_handler_(NULL)
  58   { }
  59
  60   ~Plugin()
  61   { }
  62
  63   // Load the library and call its entry point.
  64   void
  65   load();
  66
  67   // Call the claim-file handler.
  68   bool
  69   claim_file(struct ld_plugin_input_file *plugin_input_file);
  70
  71   // Call the all-symbols-read handler.
  72   void
  73   all_symbols_read();
  74
  75   // Call the cleanup handler.
  76   void
  77   cleanup();
  78
  79   // Register a claim-file handler.
  80   void
  81   set_claim_file_handler(ld_plugin_claim_file_handler handler)
  82   { this->claim_file_handler_ = handler; }
  83
  84   // Register an all-symbols-read handler.
  85   void
  86   set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)
  87   { this->all_symbols_read_handler_ = handler; }
  88
  89   // Register a claim-file handler.
  90   void
  91   set_cleanup_handler(ld_plugin_cleanup_handler handler)
  92   { this->cleanup_handler_ = handler; }
  93
  94   // Add an argument
  95   void
  96   add_option(const char *arg)
  97   {
  98     this->args_.push_back(arg);
  99   }
 100
 101  private:
 102   Plugin(const Plugin&);
 103   Plugin& operator=(const Plugin&);
 104
 105   // The shared library handle returned by dlopen.
 106   void* handle_;
 107   // The argument string given to --plugin.
 108   std::string filename_;
 109   // The list of argument string given to --plugin-opt.
 110   std::vector<std::string> args_;
 111   // The plugin's event handlers.
 112   ld_plugin_claim_file_handler claim_file_handler_;
 113   ld_plugin_all_symbols_read_handler all_symbols_read_handler_;
 114   ld_plugin_cleanup_handler cleanup_handler_;
 115 };
 116
 117 // A manager class for plugins.
 118
 119 class Plugin_manager
 120 {
 121  public:
 122   Plugin_manager(const General_options& options)
 123     : plugins_(), objects_(), deferred_layout_objects_(), input_file_(NULL),
 124       plugin_input_file_(), in_replacement_phase_(false), options_(options),
 125       workqueue_(NULL), input_objects_(NULL), symtab_(NULL), layout_(NULL),
 126       dirpath_(NULL), mapfile_(NULL), this_blocker_(NULL)
 127   { this->current_ = plugins_.end(); }
 128
 129   ~Plugin_manager();
 130
 131   // Add a plugin library.
 132   void
 133   add_plugin(const char* filename)
 134   { this->plugins_.push_back(new Plugin(filename)); }
 135
 136   // Add an argument to the current plugin.
 137   void
 138   add_plugin_option(const char* opt)
 139   {
 140     Plugin* last = this->plugins_.back();
 141     last->add_option(opt);
 142   }
 143
 144   // Load all plugin libraries.
 145   void
 146   load_plugins();
 147
 148   // Call the plugin claim-file handlers in turn to see if any claim the file.
 149   Pluginobj*
 150   claim_file(Input_file *input_file, off_t offset, off_t filesize);
 151
 152   // Call the all-symbols-read handlers.
 153   void
 154   all_symbols_read(Workqueue* workqueue, Input_objects* input_objects,
 155                    Symbol_table* symtab, Layout* layout, Dirsearch* dirpath,
 156                    Mapfile* mapfile, Task_token** last_blocker);
 157
 158   // Run deferred layout and call the cleanup handlers.
 159   void
 160   finish();
 161
 162   // Register a claim-file handler.
 163   void
 164   set_claim_file_handler(ld_plugin_claim_file_handler handler)
 165   {
 166     gold_assert(this->current_ != plugins_.end());
 167     (*this->current_)->set_claim_file_handler(handler);
 168   }
 169
 170   // Register an all-symbols-read handler.
 171   void
 172   set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)
 173   {
 174     gold_assert(this->current_ != plugins_.end());
 175     (*this->current_)->set_all_symbols_read_handler(handler);
 176   }
 177
 178   // Register a claim-file handler.
 179   void
 180   set_cleanup_handler(ld_plugin_cleanup_handler handler)
 181   {
 182     gold_assert(this->current_ != plugins_.end());
 183     (*this->current_)->set_cleanup_handler(handler);
 184   }
 185
 186   // Make a new Pluginobj object.  This is called when the plugin calls
 187   // the add_symbols API.
 188   Pluginobj*
 189   make_plugin_object(unsigned int handle);
 190
 191   // Return the Pluginobj associated with the given HANDLE.
 192   Pluginobj*
 193   object(unsigned int handle) const
 194   {
 195     if (handle >= this->objects_.size())
 196       return NULL;
 197     return this->objects_[handle];
 198   }
 199
 200   // Return TRUE if any input files have been claimed by a plugin
 201   // and we are still in the initial input phase.
 202   bool
 203   should_defer_layout() const
 204   { return !this->objects_.empty() && !this->in_replacement_phase_; }
 205
 206   // Add a regular object to the deferred layout list.  These are
 207   // objects whose layout has been deferred until after the
 208   // replacement files have arrived.
 209   void
 210   add_deferred_layout_object(Relobj* obj)
 211   { this->deferred_layout_objects_.push_back(obj); }
 212
 213   // Add a new input file.
 214   ld_plugin_status
 215   add_input_file(char *pathname);
 216
 217   // Return TRUE if we are in the replacement phase.
 218   bool
 219   in_replacement_phase() const
 220   { return this->in_replacement_phase_; }
 221
 222  private:
 223   Plugin_manager(const Plugin_manager&);
 224   Plugin_manager& operator=(const Plugin_manager&);
 225
 226   typedef std::list<Plugin*> Plugin_list;
 227   typedef std::vector<Pluginobj*> Object_list;
 228   typedef std::vector<Relobj*> Deferred_layout_list;
 229
 230   // The list of plugin libraries.
 231   Plugin_list plugins_;
 232   // A pointer to the current plugin.  Used while loading plugins.
 233   Plugin_list::iterator current_;
 234
 235   // The list of plugin objects.  The index of an item in this list
 236   // serves as the "handle" that we pass to the plugins.
 237   Object_list objects_;
 238
 239   // The list of regular objects whose layout has been deferred.
 240   Deferred_layout_list deferred_layout_objects_;
 241
 242   // The file currently up for claim by the plugins.
 243   Input_file* input_file_;
 244   struct ld_plugin_input_file plugin_input_file_;
 245
 246   // TRUE after the all symbols read event; indicates that we are
 247   // processing replacement files whose symbols should replace the
 248   // placeholder symbols from the Pluginobj objects.
 249   bool in_replacement_phase_;
 250
 251   const General_options& options_;
 252   Workqueue* workqueue_;
 253   Input_objects* input_objects_;
 254   Symbol_table* symtab_;
 255   Layout* layout_;
 256   Dirsearch* dirpath_;
 257   Mapfile* mapfile_;
 258   Task_token* this_blocker_;
 259 };
 260
 261
 262 // An object file claimed by a plugin.  This is an abstract base class.
 263 // The implementation is the template class Sized_pluginobj.
 264
 265 class Pluginobj : public Object
 266 {
 267  public:
 268
 269   typedef std::vector<Symbol*> Symbols;
 270
 271   Pluginobj(const std::string& name, Input_file* input_file, off_t offset);
 272
 273   // Fill in the symbol resolution status for the given plugin symbols.
 274   ld_plugin_status
 275   get_symbol_resolution_info(int nsyms, ld_plugin_symbol* syms) const;
 276
 277   // Add symbol information to the global symbol table.
 278   void
 279   add_symbols(Symbol_table* symtab, Layout* layout)
 280   { this->do_add_symbols(symtab, layout); }
 281
 282   // Store the incoming symbols from the plugin for later processing.
 283   void
 284   store_incoming_symbols(int nsyms, const struct ld_plugin_symbol* syms)
 285   {
 286     this->nsyms_ = nsyms;
 287     this->syms_ = syms;
 288   }
 289
 290   // Return TRUE if the comdat group with key COMDAT_KEY from this object
 291   // should be kept.
 292   bool
 293   include_comdat_group(std::string comdat_key, Layout* layout);
 294
 295  protected:
 296   // Return TRUE if this is an object claimed by a plugin.
 297   virtual Pluginobj*
 298   do_pluginobj()
 299   { return this; }
 300
 301   // Add symbol information to the global symbol table--implemented by
 302   // child class.
 303   virtual void
 304   do_add_symbols(Symbol_table*, Layout*) = 0;
 305
 306   // The number of symbols provided by the plugin.
 307   int nsyms_;
 308
 309   // The symbols provided by the plugin.
 310   const struct ld_plugin_symbol* syms_;
 311
 312   // The entries in the symbol table for the external symbols.
 313   Symbols symbols_;
 314
 315  private:
 316   // Map a comdat key symbol to a boolean indicating whether the comdat
 317   // group in this object with that key should be kept.
 318   typedef Unordered_map<std::string, bool> Comdat_map;
 319   Comdat_map comdat_map_;
 320 };
 321
 322 // A plugin object, size-specific version.
 323
 324 template<int size, bool big_endian>
 325 class Sized_pluginobj : public Pluginobj
 326 {
 327  public:
 328   Sized_pluginobj(const std::string& name, Input_file* input_file,
 329                   off_t offset);
 330
 331   // Read the symbols.
 332   void
 333   do_read_symbols(Read_symbols_data*);
 334
 335   // Lay out the input sections.
 336   void
 337   do_layout(Symbol_table*, Layout*, Read_symbols_data*);
 338
 339   // Add the symbols to the symbol table.
 340   void
 341   do_add_symbols(Symbol_table*, Read_symbols_data*);
 342
 343   void
 344   do_add_symbols(Symbol_table*, Layout*);
 345
 346   // Get the size of a section.
 347   uint64_t
 348   do_section_size(unsigned int shndx);
 349
 350   // Get the name of a section.
 351   std::string
 352   do_section_name(unsigned int shndx);
 353
 354   // Return a view of the contents of a section.
 355   Object::Location
 356   do_section_contents(unsigned int shndx);
 357
 358   // Return section flags.
 359   uint64_t
 360   do_section_flags(unsigned int shndx);
 361
 362   // Return section address.
 363   uint64_t
 364   do_section_address(unsigned int shndx);
 365
 366   // Return section type.
 367   unsigned int
 368   do_section_type(unsigned int shndx);
 369
 370   // Return the section link field.
 371   unsigned int
 372   do_section_link(unsigned int shndx);
 373
 374   // Return the section link field.
 375   unsigned int
 376   do_section_info(unsigned int shndx);
 377
 378   // Return the section alignment.
 379   uint64_t
 380   do_section_addralign(unsigned int shndx);
 381
 382   // Return the Xindex structure to use.
 383   Xindex*
 384   do_initialize_xindex();
 385
 386   // Get symbol counts.
 387   void
 388   do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
 389
 390   // Add placeholder symbols from a claimed file.
 391   ld_plugin_status
 392   add_symbols_from_plugin(int nsyms, const ld_plugin_symbol* syms);
 393
 394  protected:
 395
 396  private:
 397 };
 398
 399 // This Task handles adding the symbols to the symbol table.  These
 400 // tasks must be run in the same order as the arguments appear on the
 401 // command line.
 402
 403 class Add_plugin_symbols : public Task
 404 {
 405  public:
 406   // THIS_BLOCKER is used to prevent this task from running before the
 407   // one for the previous input file.  NEXT_BLOCKER is used to prevent
 408   // the next task from running.
 409   Add_plugin_symbols(Symbol_table* symtab,
 410                      Layout* layout,
 411                      Pluginobj* obj,
 412                      Task_token* this_blocker,
 413                      Task_token* next_blocker)
 414     : symtab_(symtab), layout_(layout), obj_(obj),
 415       this_blocker_(this_blocker), next_blocker_(next_blocker)
 416   { }
 417
 418   ~Add_plugin_symbols();
 419
 420   // The standard Task methods.
 421
 422   Task_token*
 423   is_runnable();
 424
 425   void
 426   locks(Task_locker*);
 427
 428   void
 429   run(Workqueue*);
 430
 431   std::string
 432   get_name() const
 433   { return "Add_plugin_symbols " + this->obj_->name(); }
 434
 435 private:
 436   Symbol_table* symtab_;
 437   Layout* layout_;
 438   Pluginobj* obj_;
 439   Task_token* this_blocker_;
 440   Task_token* next_blocker_;
 441 };
 442
 443 // This Task handles handles the "all symbols read" event hook.
 444 // The plugin may add additional input files at this time, which must
 445 // be queued for reading.
 446
 447 class Plugin_hook : public Task
 448 {
 449  public:
 450   Plugin_hook(const General_options& options, Input_objects* input_objects,
 451               Symbol_table* symtab, Layout* layout, Dirsearch* dirpath,
 452               Mapfile* mapfile, Task_token* this_blocker,
 453               Task_token* next_blocker)
 454     : options_(options), input_objects_(input_objects), symtab_(symtab),
 455       layout_(layout), dirpath_(dirpath), mapfile_(mapfile),
 456       this_blocker_(this_blocker), next_blocker_(next_blocker)
 457   { }
 458
 459   ~Plugin_hook();
 460
 461   // The standard Task methods.
 462
 463   Task_token*
 464   is_runnable();
 465
 466   void
 467   locks(Task_locker*);
 468
 469   void
 470   run(Workqueue*);
 471
 472   std::string
 473   get_name() const
 474   { return "Plugin_hook"; }
 475
 476  private:
 477   const General_options& options_;
 478   Input_objects* input_objects_;
 479   Symbol_table* symtab_;
 480   Layout* layout_;
 481   Dirsearch* dirpath_;
 482   Mapfile* mapfile_;
 483   Task_token* this_blocker_;
 484   Task_token* next_blocker_;
 485 };
 486
 487 } // End namespace gold.
 488
 489 #endif // !defined(GOLD_PLUGIN_H)