gold/archive.h

   1 // archive.h -- archive support for gold      -*- C++ -*-
   2
   3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@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_ARCHIVE_H
  24 #define GOLD_ARCHIVE_H
  25
  26 #include <string>
  27 #include <vector>
  28
  29 #include "fileread.h"
  30 #include "workqueue.h"
  31
  32 namespace gold
  33 {
  34
  35 class Task;
  36 class Input_argument;
  37 class Input_file;
  38 class Input_objects;
  39 class Input_group;
  40 class Layout;
  41 class Symbol_table;
  42 class Object;
  43 class Read_symbols_data;
  44 class Input_file_lib;
  45
  46 // An entry in the archive map of offsets to members.
  47 struct Archive_member
  48 {
  49   Archive_member()
  50       : obj_(NULL), sd_(NULL)
  51   { }
  52   Archive_member(Object* obj, Read_symbols_data* sd)
  53       : obj_(obj), sd_(sd)
  54   { }
  55   // The object file.
  56   Object* obj_;
  57   // The data to pass from read_symbols() to add_symbols().
  58   Read_symbols_data* sd_;
  59 };
  60
  61 // This class represents an archive--generally a libNAME.a file.
  62 // Archives have a symbol table and a list of objects.
  63
  64 class Archive
  65 {
  66  public:
  67   Archive(const std::string& name, Input_file* input_file,
  68           bool is_thin_archive, Dirsearch* dirpath, Task* task);
  69
  70   // The length of the magic string at the start of an archive.
  71   static const int sarmag = 8;
  72
  73   // The magic string at the start of an archive.
  74   static const char armag[sarmag];
  75   static const char armagt[sarmag];
  76
  77   // The string expected at the end of an archive member header.
  78   static const char arfmag[2];
  79
  80   // The name of the object.  This is the name used on the command
  81   // line; e.g., if "-lgcc" is on the command line, this will be
  82   // "gcc".
  83   const std::string&
  84   name() const
  85   { return this->name_; }
  86
  87   // The input file.
  88   const Input_file*
  89   input_file() const
  90   { return this->input_file_; }
  91
  92   // The file name.
  93   const std::string&
  94   filename() const
  95   { return this->input_file_->filename(); }
  96
  97   // Set up the archive: read the symbol map.
  98   void
  99   setup();
 100
 101   // Get a reference to the underlying file.
 102   File_read&
 103   file()
 104   { return this->input_file_->file(); }
 105
 106   const File_read&
 107   file() const
 108   { return this->input_file_->file(); }
 109
 110   // Lock the underlying file.
 111   void
 112   lock(const Task* t)
 113   { this->input_file_->file().lock(t); }
 114
 115   // Unlock the underlying file.
 116   void
 117   unlock(const Task* t)
 118   { this->input_file_->file().unlock(t); }
 119
 120   // Return whether the underlying file is locked.
 121   bool
 122   is_locked() const
 123   { return this->input_file_->file().is_locked(); }
 124
 125   // Return the token, so that the task can be queued.
 126   Task_token*
 127   token()
 128   { return this->input_file_->file().token(); }
 129
 130   // Release the underlying file.
 131   void
 132   release()
 133   { this->input_file_->file().release(); }
 134
 135   // Clear uncached views in the underlying file.
 136   void
 137   clear_uncached_views()
 138   { this->input_file_->file().clear_uncached_views(); }
 139
 140   // Whether this is a thin archive.
 141   bool
 142   is_thin_archive() const
 143   { return this->is_thin_archive_; }
 144
 145   // Unlock any nested archives.
 146   void
 147   unlock_nested_archives();
 148
 149   // Select members from the archive as needed and add them to the
 150   // link.
 151   bool
 152   add_symbols(Symbol_table*, Layout*, Input_objects*, Mapfile*);
 153
 154   // Dump statistical information to stderr.
 155   static void
 156   print_stats();
 157
 158   // Return the number of members in the archive.
 159   size_t
 160   count_members();
 161
 162   // Return the no-export flag.
 163   bool
 164   no_export()
 165   { return this->no_export_; }
 166
 167   // When we see a symbol in an archive we might decide to include the member,
 168   // not include the member or be undecided. This enum represents these
 169   // possibilities.
 170
 171   enum Should_include
 172   {
 173     SHOULD_INCLUDE_NO,
 174     SHOULD_INCLUDE_YES,
 175     SHOULD_INCLUDE_UNKNOWN
 176   };
 177
 178   static Should_include
 179   should_include_member(Symbol_table* symtab, Layout*, const char* sym_name,
 180                         Symbol** symp, std::string* why, char** tmpbufp,
 181                         size_t* tmpbuflen);
 182
 183  private:
 184   Archive(const Archive&);
 185   Archive& operator=(const Archive&);
 186
 187   struct Archive_header;
 188
 189   // Total number of archives seen.
 190   static unsigned int total_archives;
 191   // Total number of archive members seen.
 192   static unsigned int total_members;
 193   // Number of archive members loaded.
 194   static unsigned int total_members_loaded;
 195
 196   // Get a view into the underlying file.
 197   const unsigned char*
 198   get_view(off_t start, section_size_type size, bool aligned, bool cache)
 199   { return this->input_file_->file().get_view(0, start, size, aligned, cache); }
 200
 201   // Read the archive symbol map.
 202   void
 203   read_armap(off_t start, section_size_type size);
 204
 205   // Read an archive member header at OFF.  CACHE is whether to cache
 206   // the file view.  Return the size of the member, and set *PNAME to
 207   // the name.
 208   off_t
 209   read_header(off_t off, bool cache, std::string* pname, off_t* nested_off);
 210
 211   // Interpret an archive header HDR at OFF.  Return the size of the
 212   // member, and set *PNAME to the name.
 213   off_t
 214   interpret_header(const Archive_header* hdr, off_t off, std::string* pname,
 215                    off_t* nested_off) const;
 216
 217   // Get the file and offset for an archive member, which may be an
 218   // external member of a thin archive.  Set *INPUT_FILE to the
 219   // file containing the actual member, *MEMOFF to the offset
 220   // within that file (0 if not a nested archive), and *MEMBER_NAME
 221   // to the name of the archive member.  Return TRUE on success.
 222   bool
 223   get_file_and_offset(off_t off, Input_file** input_file, off_t* memoff,
 224                       off_t* memsize, std::string* member_name);
 225
 226   // Return an ELF object for the member at offset OFF.
 227   Object*
 228   get_elf_object_for_member(off_t off, bool*);
 229
 230   // Read the symbols from all the archive members in the link.
 231   void
 232   read_all_symbols();
 233
 234   // Read the symbols from an archive member in the link.  OFF is the file
 235   // offset of the member header.
 236   void
 237   read_symbols(off_t off);
 238
 239   // Include all the archive members in the link.
 240   bool
 241   include_all_members(Symbol_table*, Layout*, Input_objects*, Mapfile*);
 242
 243   // Include an archive member in the link.
 244   bool
 245   include_member(Symbol_table*, Layout*, Input_objects*, off_t off,
 246                  Mapfile*, Symbol*, const char* why);
 247
 248   // Return whether we found this archive by searching a directory.
 249   bool
 250   searched_for() const
 251   { return this->input_file_->will_search_for(); }
 252
 253   // Iterate over archive members.
 254   class const_iterator;
 255
 256   const_iterator
 257   begin();
 258
 259   const_iterator
 260   end();
 261
 262   friend class const_iterator;
 263
 264   // An entry in the archive map of symbols to object files.
 265   struct Armap_entry
 266   {
 267     // The offset to the symbol name in armap_names_.
 268     off_t name_offset;
 269     // The file offset to the object in the archive.
 270     off_t file_offset;
 271   };
 272
 273   // A simple hash code for off_t values.
 274   class Seen_hash
 275   {
 276    public:
 277     size_t operator()(off_t val) const
 278     { return static_cast<size_t>(val); }
 279   };
 280
 281   // For keeping track of open nested archives in a thin archive file.
 282   typedef Unordered_map<std::string, Archive*> Nested_archive_table;
 283
 284   // Name of object as printed to user.
 285   std::string name_;
 286   // For reading the file.
 287   Input_file* input_file_;
 288   // The archive map.
 289   std::vector<Armap_entry> armap_;
 290   // The names in the archive map.
 291   std::string armap_names_;
 292   // The extended name table.
 293   std::string extended_names_;
 294   // Track which symbols in the archive map are for elements which are
 295   // defined or which have already been included in the link.
 296   std::vector<bool> armap_checked_;
 297   // Track which elements have been included by offset.
 298   Unordered_set<off_t, Seen_hash> seen_offsets_;
 299   // Table of objects whose symbols have been pre-read.
 300   std::map<off_t, Archive_member> members_;
 301   // True if this is a thin archive.
 302   const bool is_thin_archive_;
 303   // True if we have included at least one object from this archive.
 304   bool included_member_;
 305   // Table of nested archives, indexed by filename.
 306   Nested_archive_table nested_archives_;
 307   // The directory search path.
 308   Dirsearch* dirpath_;
 309   // The task reading this archive.
 310   Task *task_;
 311   // Number of members in this archive;
 312   unsigned int num_members_;
 313   // True if we exclude this library archive from automatic export.
 314   bool no_export_;
 315 };
 316
 317 // This class is used to read an archive and pick out the desired
 318 // elements and add them to the link.
 319
 320 class Add_archive_symbols : public Task
 321 {
 322  public:
 323   Add_archive_symbols(Symbol_table* symtab, Layout* layout,
 324                       Input_objects* input_objects, Dirsearch* dirpath,
 325                       int dirindex, Mapfile* mapfile,
 326                       const Input_argument* input_argument,
 327                       Archive* archive, Input_group* input_group,
 328                       Task_token* this_blocker,
 329                       Task_token* next_blocker)
 330     : symtab_(symtab), layout_(layout), input_objects_(input_objects),
 331       dirpath_(dirpath), dirindex_(dirindex), mapfile_(mapfile),
 332       input_argument_(input_argument), archive_(archive),
 333       input_group_(input_group), this_blocker_(this_blocker),
 334       next_blocker_(next_blocker)
 335   { }
 336
 337   ~Add_archive_symbols();
 338
 339   // The standard Task methods.
 340
 341   Task_token*
 342   is_runnable();
 343
 344   void
 345   locks(Task_locker*);
 346
 347   void
 348   run(Workqueue*);
 349
 350   std::string
 351   get_name() const
 352   {
 353     if (this->archive_ == NULL)
 354       return "Add_archive_symbols";
 355     return "Add_archive_symbols " + this->archive_->file().filename();
 356   }
 357
 358  private:
 359   Symbol_table* symtab_;
 360   Layout* layout_;
 361   Input_objects* input_objects_;
 362   Dirsearch* dirpath_;
 363   int dirindex_;
 364   Mapfile* mapfile_;
 365   const Input_argument* input_argument_;
 366   Archive* archive_;
 367   Input_group* input_group_;
 368   Task_token* this_blocker_;
 369   Task_token* next_blocker_;
 370 };
 371
 372 // This class represents the files surrunded by a --start-lib ... --end-lib.
 373
 374 class Lib_group
 375 {
 376  public:
 377   Lib_group(const Input_file_lib* lib, Task* task);
 378
 379   // Select members from the lib group as needed and add them to the link.
 380   void
 381   add_symbols(Symbol_table*, Layout*, Input_objects*);
 382
 383   // Include a member of the lib group in the link.
 384   void
 385   include_member(Symbol_table*, Layout*, Input_objects*, const Archive_member&);
 386
 387   Archive_member*
 388   get_member(int i)
 389   {
 390     return &this->members_[i];
 391   }
 392
 393   // Dump statistical information to stderr.
 394   static void
 395   print_stats();
 396
 397   // Total number of archives seen.
 398   static unsigned int total_lib_groups;
 399   // Total number of archive members seen.
 400   static unsigned int total_members;
 401   // Number of archive members loaded.
 402   static unsigned int total_members_loaded;
 403
 404  private:
 405   // For reading the files.
 406   const Input_file_lib* lib_;
 407   // The task reading this lib group.
 408   Task *task_;
 409   // Table of the objects in the group.
 410   std::vector<Archive_member> members_;
 411 };
 412
 413 // This class is used to pick out the desired elements and add them to the link.
 414
 415 class Add_lib_group_symbols : public Task
 416 {
 417  public:
 418   Add_lib_group_symbols(Symbol_table* symtab, Layout* layout,
 419                         Input_objects* input_objects,
 420                         Lib_group* lib, Task_token* next_blocker)
 421       : symtab_(symtab), layout_(layout), input_objects_(input_objects),
 422         lib_(lib), this_blocker_(NULL), next_blocker_(next_blocker)
 423   { }
 424
 425   ~Add_lib_group_symbols();
 426
 427   // The standard Task methods.
 428
 429   Task_token*
 430   is_runnable();
 431
 432   void
 433   locks(Task_locker*);
 434
 435   void
 436   run(Workqueue*);
 437
 438   // Set the blocker to use for this task.
 439   void
 440   set_blocker(Task_token* this_blocker)
 441   {
 442     gold_assert(this->this_blocker_ == NULL);
 443     this->this_blocker_ = this_blocker;
 444   }
 445
 446   std::string
 447   get_name() const
 448   {
 449     return "Add_lib_group_symbols";
 450   }
 451
 452  private:
 453   Symbol_table* symtab_;
 454   Layout* layout_;
 455   Input_objects* input_objects_;
 456   Lib_group * lib_;
 457   Task_token* this_blocker_;
 458   Task_token* next_blocker_;
 459 };
 460
 461 } // End namespace gold.
 462
 463 #endif // !defined(GOLD_ARCHIVE_H)