gold/archive.cc

   1 // archive.cc -- archive support for gold
   2
   3 // Copyright (C) 2006-2018 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 #include "gold.h"
  24
  25 #include <cerrno>
  26 #include <cstring>
  27 #include <climits>
  28 #include <vector>
  29 #include "libiberty.h"
  30 #include "filenames.h"
  31
  32 #include "elfcpp.h"
  33 #include "options.h"
  34 #include "mapfile.h"
  35 #include "fileread.h"
  36 #include "readsyms.h"
  37 #include "symtab.h"
  38 #include "object.h"
  39 #include "layout.h"
  40 #include "archive.h"
  41 #include "plugin.h"
  42 #include "incremental.h"
  43
  44 namespace gold
  45 {
  46
  47 // Library_base methods.
  48
  49 // Determine whether a definition of SYM_NAME should cause an archive
  50 // library member to be included in the link.  Returns SHOULD_INCLUDE_YES
  51 // if the symbol is referenced but not defined, SHOULD_INCLUDE_NO if the
  52 // symbol is already defined, and SHOULD_INCLUDE_UNKNOWN if the symbol is
  53 // neither referenced nor defined.
  54
  55 Library_base::Should_include
  56 Library_base::should_include_member(Symbol_table* symtab, Layout* layout,
  57                                     const char* sym_name, Symbol** symp,
  58                                     std::string* why, char** tmpbufp,
  59                                     size_t* tmpbuflen)
  60 {
  61   // In an object file, and therefore in an archive map, an
  62   // '@' in the name separates the symbol name from the
  63   // version name.  If there are two '@' characters, this is
  64   // the default version.
  65   char* tmpbuf = *tmpbufp;
  66   const char* ver = strchr(sym_name, '@');
  67   bool def = false;
  68   if (ver != NULL)
  69     {
  70       size_t symlen = ver - sym_name;
  71       if (symlen + 1 > *tmpbuflen)
  72         {
  73           tmpbuf = static_cast<char*>(xrealloc(tmpbuf, symlen + 1));
  74           *tmpbufp = tmpbuf;
  75           *tmpbuflen = symlen + 1;
  76         }
  77       memcpy(tmpbuf, sym_name, symlen);
  78       tmpbuf[symlen] = '\0';
  79       sym_name = tmpbuf;
  80
  81       ++ver;
  82       if (*ver == '@')
  83         {
  84           ++ver;
  85           def = true;
  86         }
  87     }
  88
  89   Symbol* sym = symtab->lookup(sym_name, ver);
  90   if (def
  91       && ver != NULL
  92       && (sym == NULL
  93           || !sym->is_undefined()
  94           || sym->binding() == elfcpp::STB_WEAK))
  95     sym = symtab->lookup(sym_name, NULL);
  96
  97   *symp = sym;
  98
  99   if (sym != NULL)
 100     {
 101       if (!sym->is_undefined())
 102         return Library_base::SHOULD_INCLUDE_NO;
 103
 104       // PR 12001: Do not include an archive when the undefined
 105       // symbol has actually been defined on the command line.
 106       if (layout->script_options()->is_pending_assignment(sym_name))
 107         return Library_base::SHOULD_INCLUDE_NO;
 108
 109       // If the symbol is weak undefined, we still need to check
 110       // for other reasons (like a -u option).
 111       if (sym->binding() != elfcpp::STB_WEAK)
 112         return Library_base::SHOULD_INCLUDE_YES;
 113     }
 114
 115   // Check whether the symbol was named in a -u option.
 116   if (parameters->options().is_undefined(sym_name))
 117     {
 118       *why = "-u ";
 119       *why += sym_name;
 120       return Library_base::SHOULD_INCLUDE_YES;
 121     }
 122
 123   if (parameters->options().is_export_dynamic_symbol(sym_name))
 124     {
 125       *why = "--export-dynamic-symbol ";
 126       *why += sym_name;
 127       return Library_base::SHOULD_INCLUDE_YES;
 128     }
 129
 130   if (layout->script_options()->is_referenced(sym_name))
 131     {
 132       size_t alc = 100 + strlen(sym_name);
 133       char* buf = new char[alc];
 134       snprintf(buf, alc, _("script or expression reference to %s"),
 135                sym_name);
 136       *why = buf;
 137       delete[] buf;
 138       return Library_base::SHOULD_INCLUDE_YES;
 139     }
 140
 141   if (!parameters->options().relocatable())
 142     {
 143       const char* entry_sym = parameters->entry();
 144       if (entry_sym != NULL && strcmp(sym_name, entry_sym) == 0)
 145         {
 146           *why = "entry symbol ";
 147           *why += sym_name;
 148           return Library_base::SHOULD_INCLUDE_YES;
 149         }
 150     }
 151
 152   return Library_base::SHOULD_INCLUDE_UNKNOWN;
 153 }
 154
 155 // The header of an entry in the archive.  This is all readable text,
 156 // padded with spaces where necessary.  If the contents of an archive
 157 // are all text file, the entire archive is readable.
 158
 159 struct Archive::Archive_header
 160 {
 161   // The entry name.
 162   char ar_name[16];
 163   // The file modification time.
 164   char ar_date[12];
 165   // The user's UID in decimal.
 166   char ar_uid[6];
 167   // The user's GID in decimal.
 168   char ar_gid[6];
 169   // The file mode in octal.
 170   char ar_mode[8];
 171   // The file size in decimal.
 172   char ar_size[10];
 173   // The final magic code.
 174   char ar_fmag[2];
 175 };
 176
 177 // Class Archive static variables.
 178 unsigned int Archive::total_archives;
 179 unsigned int Archive::total_members;
 180 unsigned int Archive::total_members_loaded;
 181
 182 // Archive methods.
 183
 184 const char Archive::armag[sarmag] =
 185 {
 186   '!', '<', 'a', 'r', 'c', 'h', '>', '\n'
 187 };
 188
 189 const char Archive::armagt[sarmag] =
 190 {
 191   '!', '<', 't', 'h', 'i', 'n', '>', '\n'
 192 };
 193
 194 const char Archive::arfmag[2] = { '`', '\n' };
 195
 196 const char Archive::sym64name[7] = { '/', 'S', 'Y', 'M', '6', '4', '/' };
 197
 198 Archive::Archive(const std::string& name, Input_file* input_file,
 199                  bool is_thin_archive, Dirsearch* dirpath, Task* task)
 200   : Library_base(task), name_(name), input_file_(input_file), armap_(),
 201     armap_names_(), extended_names_(), armap_checked_(), seen_offsets_(),
 202     members_(), is_thin_archive_(is_thin_archive), included_member_(false),
 203     nested_archives_(), dirpath_(dirpath), num_members_(0),
 204     included_all_members_(false)
 205 {
 206   this->no_export_ =
 207     parameters->options().check_excluded_libs(input_file->found_name());
 208 }
 209
 210 // Set up the archive: read the symbol map and the extended name
 211 // table.
 212
 213 void
 214 Archive::setup()
 215 {
 216   // We need to ignore empty archives.
 217   if (this->input_file_->file().filesize() == sarmag)
 218     return;
 219
 220   // The first member of the archive should be the symbol table.
 221   std::string armap_name;
 222   off_t header_size = this->read_header(sarmag, false, &armap_name, NULL);
 223   if (header_size == -1)
 224     return;
 225
 226   section_size_type armap_size = convert_to_section_size_type(header_size);
 227   off_t off = sarmag;
 228   if (armap_name.empty())
 229     {
 230       this->read_armap<32>(sarmag + sizeof(Archive_header), armap_size);
 231       off = sarmag + sizeof(Archive_header) + armap_size;
 232     }
 233   else if (armap_name == "/SYM64/")
 234     {
 235       this->read_armap<64>(sarmag + sizeof(Archive_header), armap_size);
 236       off = sarmag + sizeof(Archive_header) + armap_size;
 237     }
 238   else if (!this->input_file_->options().whole_archive())
 239     gold_error(_("%s: no archive symbol table (run ranlib)"),
 240                this->name().c_str());
 241
 242   // See if there is an extended name table.  We cache these views
 243   // because it is likely that we will want to read the following
 244   // header in the add_symbols routine.
 245   if ((off & 1) != 0)
 246     ++off;
 247   std::string xname;
 248   header_size = this->read_header(off, true, &xname, NULL);
 249   if (header_size == -1)
 250     return;
 251
 252   section_size_type extended_size = convert_to_section_size_type(header_size);
 253   if (xname == "/")
 254     {
 255       const unsigned char* p = this->get_view(off + sizeof(Archive_header),
 256                                               extended_size, false, true);
 257       const char* px = reinterpret_cast<const char*>(p);
 258       this->extended_names_.assign(px, extended_size);
 259     }
 260   bool preread_syms = (parameters->options().threads()
 261                        && parameters->options().preread_archive_symbols());
 262 #ifndef ENABLE_THREADS
 263   preread_syms = false;
 264 #else
 265   if (parameters->options().has_plugins())
 266     preread_syms = false;
 267 #endif
 268   if (preread_syms)
 269     this->read_all_symbols();
 270 }
 271
 272 // Unlock any nested archives.
 273
 274 void
 275 Archive::unlock_nested_archives()
 276 {
 277   for (Nested_archive_table::iterator p = this->nested_archives_.begin();
 278        p != this->nested_archives_.end();
 279        ++p)
 280     {
 281       p->second->unlock(this->task_);
 282     }
 283 }
 284
 285 // Read the archive symbol map.
 286
 287 template<int mapsize>
 288 void
 289 Archive::read_armap(off_t start, section_size_type size)
 290 {
 291   // To count the total number of archive members, we'll just count
 292   // the number of times the file offset changes.  Since most archives
 293   // group the symbols in the armap by object, this ought to give us
 294   // an accurate count.
 295   off_t last_seen_offset = -1;
 296
 297   // Read in the entire armap.
 298   const unsigned char* p = this->get_view(start, size, true, false);
 299
 300   // Numbers in the armap are always big-endian.
 301   typedef typename elfcpp::Elf_types<mapsize>::Elf_Addr Entry_type;
 302   const Entry_type* pword = reinterpret_cast<const Entry_type*>(p);
 303   unsigned long nsyms = convert_types<unsigned long, Entry_type>(
 304     elfcpp::Swap<mapsize, true>::readval(pword));
 305   ++pword;
 306
 307   // Note that the addition is in units of sizeof(elfcpp::Elf_Word).
 308   const char* pnames = reinterpret_cast<const char*>(pword + nsyms);
 309   section_size_type names_size =
 310     reinterpret_cast<const char*>(p) + size - pnames;
 311   this->armap_names_.assign(pnames, names_size);
 312
 313   this->armap_.resize(nsyms);
 314
 315   section_offset_type name_offset = 0;
 316   for (unsigned long i = 0; i < nsyms; ++i)
 317     {
 318       this->armap_[i].name_offset = name_offset;
 319       this->armap_[i].file_offset = convert_types<off_t, Entry_type>(
 320         elfcpp::Swap<mapsize, true>::readval(pword));
 321       name_offset += strlen(pnames + name_offset) + 1;
 322       ++pword;
 323       if (this->armap_[i].file_offset != last_seen_offset)
 324         {
 325           last_seen_offset = this->armap_[i].file_offset;
 326           ++this->num_members_;
 327         }
 328     }
 329
 330   if (static_cast<section_size_type>(name_offset) > names_size)
 331     gold_error(_("%s: bad archive symbol table names"),
 332                this->name().c_str());
 333
 334   // This array keeps track of which symbols are for archive elements
 335   // which we have already included in the link.
 336   this->armap_checked_.resize(nsyms);
 337 }
 338
 339 // Read the header of an archive member at OFF.  Fail if something
 340 // goes wrong.  Return the size of the member.  Set *PNAME to the name
 341 // of the member.
 342
 343 off_t
 344 Archive::read_header(off_t off, bool cache, std::string* pname,
 345                      off_t* nested_off)
 346 {
 347   const unsigned char* p = this->get_view(off, sizeof(Archive_header), true,
 348                                           cache);
 349   const Archive_header* hdr = reinterpret_cast<const Archive_header*>(p);
 350   return this->interpret_header(hdr, off,  pname, nested_off);
 351 }
 352
 353 // Interpret the header of HDR, the header of the archive member at
 354 // file offset OFF.  Return the size of the member, or -1 if something
 355 // has gone wrong.  Set *PNAME to the name of the member.
 356
 357 off_t
 358 Archive::interpret_header(const Archive_header* hdr, off_t off,
 359                           std::string* pname, off_t* nested_off) const
 360 {
 361   if (memcmp(hdr->ar_fmag, arfmag, sizeof arfmag) != 0)
 362     {
 363       gold_error(_("%s: malformed archive header at %zu"),
 364                  this->name().c_str(), static_cast<size_t>(off));
 365       return -1;
 366     }
 367
 368   const int size_string_size = sizeof hdr->ar_size;
 369   char size_string[size_string_size + 1];
 370   memcpy(size_string, hdr->ar_size, size_string_size);
 371   char* ps = size_string + size_string_size;
 372   while (ps[-1] == ' ')
 373     --ps;
 374   *ps = '\0';
 375
 376   errno = 0;
 377   char* end;
 378   off_t member_size = strtol(size_string, &end, 10);
 379   if (*end != '\0'
 380       || member_size < 0
 381       || (member_size == LONG_MAX && errno == ERANGE))
 382     {
 383       gold_error(_("%s: malformed archive header size at %zu"),
 384                  this->name().c_str(), static_cast<size_t>(off));
 385       return -1;
 386     }
 387
 388   if (hdr->ar_name[0] != '/')
 389     {
 390       const char* name_end = strchr(hdr->ar_name, '/');
 391       if (name_end == NULL
 392           || name_end - hdr->ar_name >= static_cast<int>(sizeof hdr->ar_name))
 393         {
 394           gold_error(_("%s: malformed archive header name at %zu"),
 395                      this->name().c_str(), static_cast<size_t>(off));
 396           return -1;
 397         }
 398       pname->assign(hdr->ar_name, name_end - hdr->ar_name);
 399       if (nested_off != NULL)
 400         *nested_off = 0;
 401     }
 402   else if (hdr->ar_name[1] == ' ')
 403     {
 404       // This is the symbol table.
 405       if (!pname->empty())
 406         pname->clear();
 407     }
 408   else if (memcmp(hdr->ar_name, sym64name, sizeof sym64name) == 0)
 409     {
 410       // This is the symbol table, 64-bit version.
 411       pname->assign(sym64name, sizeof sym64name);
 412     }
 413   else if (hdr->ar_name[1] == '/')
 414     {
 415       // This is the extended name table.
 416       pname->assign(1, '/');
 417     }
 418   else
 419     {
 420       errno = 0;
 421       long x = strtol(hdr->ar_name + 1, &end, 10);
 422       long y = 0;
 423       if (*end == ':')
 424         y = strtol(end + 1, &end, 10);
 425       if (*end != ' '
 426           || x < 0
 427           || (x == LONG_MAX && errno == ERANGE)
 428           || static_cast<size_t>(x) >= this->extended_names_.size())
 429         {
 430           gold_error(_("%s: bad extended name index at %zu"),
 431                      this->name().c_str(), static_cast<size_t>(off));
 432           return -1;
 433         }
 434
 435       const char* name = this->extended_names_.data() + x;
 436       const char* name_end = strchr(name, '\n');
 437       if (static_cast<size_t>(name_end - name) > this->extended_names_.size()
 438           || name_end[-1] != '/')
 439         {
 440           gold_error(_("%s: bad extended name entry at header %zu"),
 441                      this->name().c_str(), static_cast<size_t>(off));
 442           return -1;
 443         }
 444       pname->assign(name, name_end - 1 - name);
 445       if (nested_off != NULL)
 446         *nested_off = y;
 447     }
 448
 449   return member_size;
 450 }
 451
 452 // An archive member iterator.
 453
 454 class Archive::const_iterator
 455 {
 456  public:
 457   // The header of an archive member.  This is what this iterator
 458   // points to.
 459   struct Header
 460   {
 461     // The name of the member.
 462     std::string name;
 463     // The file offset of the member.
 464     off_t off;
 465     // The file offset of a nested archive member.
 466     off_t nested_off;
 467     // The size of the member.
 468     off_t size;
 469   };
 470
 471   const_iterator(Archive* archive, off_t off)
 472     : archive_(archive), off_(off)
 473   { this->read_next_header(); }
 474
 475   const Header&
 476   operator*() const
 477   { return this->header_; }
 478
 479   const Header*
 480   operator->() const
 481   { return &this->header_; }
 482
 483   const_iterator&
 484   operator++()
 485   {
 486     if (this->off_ == this->archive_->file().filesize())
 487       return *this;
 488     this->off_ += sizeof(Archive_header);
 489     if (!this->archive_->is_thin_archive())
 490       this->off_ += this->header_.size;
 491     if ((this->off_ & 1) != 0)
 492       ++this->off_;
 493     this->read_next_header();
 494     return *this;
 495   }
 496
 497   const_iterator
 498   operator++(int)
 499   {
 500     const_iterator ret = *this;
 501     ++*this;
 502     return ret;
 503   }
 504
 505   bool
 506   operator==(const const_iterator p) const
 507   { return this->off_ == p->off; }
 508
 509   bool
 510   operator!=(const const_iterator p) const
 511   { return this->off_ != p->off; }
 512
 513  private:
 514   void
 515   read_next_header();
 516
 517   // The underlying archive.
 518   Archive* archive_;
 519   // The current offset in the file.
 520   off_t off_;
 521   // The current archive header.
 522   Header header_;
 523 };
 524
 525 // Read the next archive header.
 526
 527 void
 528 Archive::const_iterator::read_next_header()
 529 {
 530   off_t filesize = this->archive_->file().filesize();
 531   while (true)
 532     {
 533       if (filesize - this->off_ < static_cast<off_t>(sizeof(Archive_header)))
 534         {
 535           if (filesize != this->off_)
 536             {
 537               gold_error(_("%s: short archive header at %zu"),
 538                          this->archive_->filename().c_str(),
 539                          static_cast<size_t>(this->off_));
 540               this->off_ = filesize;
 541             }
 542           this->header_.off = filesize;
 543           return;
 544         }
 545
 546       unsigned char buf[sizeof(Archive_header)];
 547       this->archive_->file().read(this->off_, sizeof(Archive_header), buf);
 548
 549       const Archive_header* hdr = reinterpret_cast<const Archive_header*>(buf);
 550       off_t size = this->archive_->interpret_header(hdr, this->off_,
 551                                                     &this->header_.name,
 552                                                     &this->header_.nested_off);
 553       if (size == -1)
 554         {
 555           this->header_.off = filesize;
 556           return;
 557         }
 558
 559       this->header_.size = size;
 560       this->header_.off = this->off_;
 561
 562       // Skip special members.
 563       if (!this->header_.name.empty()
 564           && this->header_.name != "/"
 565           && this->header_.name != "/SYM64/")
 566         return;
 567
 568       this->off_ += sizeof(Archive_header) + this->header_.size;
 569       if ((this->off_ & 1) != 0)
 570         ++this->off_;
 571     }
 572 }
 573
 574 // Initial iterator.
 575
 576 Archive::const_iterator
 577 Archive::begin()
 578 {
 579   return Archive::const_iterator(this, sarmag);
 580 }
 581
 582 // Final iterator.
 583
 584 Archive::const_iterator
 585 Archive::end()
 586 {
 587   return Archive::const_iterator(this, this->input_file_->file().filesize());
 588 }
 589
 590 // Get the file and offset for an archive member, which may be an
 591 // external member of a thin archive.  Set *INPUT_FILE to the
 592 // file containing the actual member, *MEMOFF to the offset
 593 // within that file (0 if not a nested archive), and *MEMBER_NAME
 594 // to the name of the archive member.  Return TRUE on success.
 595
 596 bool
 597 Archive::get_file_and_offset(off_t off, Input_file** input_file, off_t* memoff,
 598                              off_t* memsize, std::string* member_name)
 599 {
 600   off_t nested_off;
 601
 602   *memsize = this->read_header(off, false, member_name, &nested_off);
 603   if (*memsize == -1)
 604     return false;
 605
 606   *input_file = this->input_file_;
 607   *memoff = off + static_cast<off_t>(sizeof(Archive_header));
 608
 609   if (!this->is_thin_archive_)
 610     return true;
 611
 612   // Adjust a relative pathname so that it is relative
 613   // to the directory containing the archive.
 614   if (!IS_ABSOLUTE_PATH(member_name->c_str()))
 615     {
 616       const char* arch_path = this->filename().c_str();
 617       const char* basename = lbasename(arch_path);
 618       if (basename > arch_path)
 619         member_name->replace(0, 0,
 620                              this->filename().substr(0, basename - arch_path));
 621     }
 622
 623   if (nested_off > 0)
 624     {
 625       // This is a member of a nested archive.  Open the containing
 626       // archive if we don't already have it open, then do a recursive
 627       // call to include the member from that archive.
 628       Archive* arch;
 629       Nested_archive_table::const_iterator p =
 630         this->nested_archives_.find(*member_name);
 631       if (p != this->nested_archives_.end())
 632         arch = p->second;
 633       else
 634         {
 635           Input_file_argument* input_file_arg =
 636             new Input_file_argument(member_name->c_str(),
 637                                     Input_file_argument::INPUT_FILE_TYPE_FILE,
 638                                     "", false, parameters->options());
 639           *input_file = new Input_file(input_file_arg);
 640           int dummy = 0;
 641           if (!(*input_file)->open(*this->dirpath_, this->task_, &dummy))
 642             return false;
 643           arch = new Archive(*member_name, *input_file, false, this->dirpath_,
 644                              this->task_);
 645           arch->setup();
 646           std::pair<Nested_archive_table::iterator, bool> ins =
 647             this->nested_archives_.insert(std::make_pair(*member_name, arch));
 648           gold_assert(ins.second);
 649         }
 650       return arch->get_file_and_offset(nested_off, input_file, memoff,
 651                                        memsize, member_name);
 652     }
 653
 654   // This is an external member of a thin archive.  Open the
 655   // file as a regular relocatable object file.
 656   Input_file_argument* input_file_arg =
 657       new Input_file_argument(member_name->c_str(),
 658                               Input_file_argument::INPUT_FILE_TYPE_FILE,
 659                               "", false, this->input_file_->options());
 660   *input_file = new Input_file(input_file_arg);
 661   int dummy = 0;
 662   if (!(*input_file)->open(*this->dirpath_, this->task_, &dummy))
 663     return false;
 664
 665   *memoff = 0;
 666   *memsize = (*input_file)->file().filesize();
 667   return true;
 668 }
 669
 670 // Return an ELF object for the member at offset OFF.  If
 671 // PUNCONFIGURED is not NULL, then if the ELF object has an
 672 // unsupported target type, set *PUNCONFIGURED to true and return
 673 // NULL.
 674
 675 Object*
 676 Archive::get_elf_object_for_member(off_t off, bool* punconfigured)
 677 {
 678   if (punconfigured != NULL)
 679     *punconfigured = false;
 680
 681   Input_file* input_file;
 682   off_t memoff;
 683   off_t memsize;
 684   std::string member_name;
 685   if (!this->get_file_and_offset(off, &input_file, &memoff, &memsize,
 686                                  &member_name))
 687     return NULL;
 688
 689   const unsigned char* ehdr;
 690   int read_size;
 691   Object *obj = NULL;
 692   bool is_elf_obj = false;
 693   bool unclaimed = false;
 694
 695   if (is_elf_object(input_file, memoff, &ehdr, &read_size))
 696     {
 697       obj = make_elf_object((std::string(this->input_file_->filename())
 698                              + "(" + member_name + ")"),
 699                             input_file, memoff, ehdr, read_size,
 700                             punconfigured);
 701       is_elf_obj = true;
 702     }
 703
 704   if (parameters->options().has_plugins())
 705     {
 706       Object* plugin_obj
 707         = parameters->options().plugins()->claim_file(input_file,
 708                                                       memoff,
 709                                                       memsize,
 710                                                       obj);
 711       if (plugin_obj != NULL)
 712         {
 713           // The input file was claimed by a plugin, and its symbols
 714           // have been provided by the plugin.
 715           // Delete its elf object.
 716           if (obj != NULL)
 717             delete obj;
 718           return plugin_obj;
 719         }
 720
 721       unclaimed = true;
 722     }
 723
 724   if (!is_elf_obj)
 725     {
 726       if (unclaimed)
 727         gold_error(_("%s: plugin failed to claim member %s at %zu"),
 728                    this->name().c_str(), member_name.c_str(),
 729                    static_cast<size_t>(off));
 730       else
 731         gold_error(_("%s: member %s at %zu is not an ELF object"),
 732                    this->name().c_str(), member_name.c_str(),
 733                    static_cast<size_t>(off));
 734       return NULL;
 735     }
 736
 737   if (obj == NULL)
 738     return NULL;
 739   obj->set_no_export(this->no_export());
 740   return obj;
 741 }
 742
 743 // Read the symbols from all the archive members in the link.
 744
 745 void
 746 Archive::read_all_symbols()
 747 {
 748   for (Archive::const_iterator p = this->begin();
 749        p != this->end();
 750        ++p)
 751     this->read_symbols(p->off);
 752 }
 753
 754 // Read the symbols from an archive member in the link.  OFF is the file
 755 // offset of the member header.
 756
 757 void
 758 Archive::read_symbols(off_t off)
 759 {
 760   Object* obj = this->get_elf_object_for_member(off, NULL);
 761   if (obj == NULL)
 762     return;
 763
 764   Read_symbols_data* sd = new Read_symbols_data;
 765   obj->read_symbols(sd);
 766   Archive_member member(obj, sd);
 767   this->members_[off] = member;
 768 }
 769
 770 // Select members from the archive and add them to the link.  We walk
 771 // through the elements in the archive map, and look each one up in
 772 // the symbol table.  If it exists as a strong undefined symbol, we
 773 // pull in the corresponding element.  We have to do this in a loop,
 774 // since pulling in one element may create new undefined symbols which
 775 // may be satisfied by other objects in the archive.  Return true in
 776 // the normal case, false if the first member we tried to add from
 777 // this archive had an incompatible target.
 778
 779 bool
 780 Archive::add_symbols(Symbol_table* symtab, Layout* layout,
 781                      Input_objects* input_objects, Mapfile* mapfile)
 782 {
 783   ++Archive::total_archives;
 784
 785   if (this->input_file_->options().whole_archive())
 786     return this->include_all_members(symtab, layout, input_objects,
 787                                      mapfile);
 788
 789   Archive::total_members += this->num_members_;
 790
 791   input_objects->archive_start(this);
 792
 793   const size_t armap_size = this->armap_.size();
 794
 795   // This is a quick optimization, since we usually see many symbols
 796   // in a row with the same offset.  last_seen_offset holds the last
 797   // offset we saw that was present in the seen_offsets_ set.
 798   off_t last_seen_offset = -1;
 799
 800   // Track which symbols in the symbol table we've already found to be
 801   // defined.
 802
 803   char* tmpbuf = NULL;
 804   size_t tmpbuflen = 0;
 805   bool added_new_object;
 806   do
 807     {
 808       added_new_object = false;
 809       for (size_t i = 0; i < armap_size; ++i)
 810         {
 811           if (this->armap_checked_[i])
 812             continue;
 813           if (this->armap_[i].file_offset == last_seen_offset)
 814             {
 815               this->armap_checked_[i] = true;
 816               continue;
 817             }
 818           if (this->seen_offsets_.find(this->armap_[i].file_offset)
 819               != this->seen_offsets_.end())
 820             {
 821               this->armap_checked_[i] = true;
 822               last_seen_offset = this->armap_[i].file_offset;
 823               continue;
 824             }
 825
 826           const char* sym_name = (this->armap_names_.data()
 827                                   + this->armap_[i].name_offset);
 828
 829           Symbol* sym;
 830           std::string why;
 831           Archive::Should_include t =
 832             Archive::should_include_member(symtab, layout, sym_name, &sym,
 833                                            &why, &tmpbuf, &tmpbuflen);
 834
 835           if (t == Archive::SHOULD_INCLUDE_NO
 836               || t == Archive::SHOULD_INCLUDE_YES)
 837             this->armap_checked_[i] = true;
 838
 839           if (t != Archive::SHOULD_INCLUDE_YES)
 840             continue;
 841
 842           // We want to include this object in the link.
 843           last_seen_offset = this->armap_[i].file_offset;
 844           this->seen_offsets_.insert(last_seen_offset);
 845
 846           if (!this->include_member(symtab, layout, input_objects,
 847                                     last_seen_offset, mapfile, sym,
 848                                     why.c_str()))
 849             {
 850               if (tmpbuf != NULL)
 851                 free(tmpbuf);
 852               return false;
 853             }
 854
 855           added_new_object = true;
 856         }
 857     }
 858   while (added_new_object);
 859
 860   if (tmpbuf != NULL)
 861     free(tmpbuf);
 862
 863   input_objects->archive_stop(this);
 864
 865   return true;
 866 }
 867
 868 // Return whether the archive includes a member which defines the
 869 // symbol SYM.
 870
 871 bool
 872 Archive::defines_symbol(Symbol* sym) const
 873 {
 874   const char* symname = sym->name();
 875   size_t symname_len = strlen(symname);
 876   size_t armap_size = this->armap_.size();
 877   for (size_t i = 0; i < armap_size; ++i)
 878     {
 879       if (this->armap_checked_[i])
 880         continue;
 881       const char* archive_symname = (this->armap_names_.data()
 882                                      + this->armap_[i].name_offset);
 883       if (strncmp(archive_symname, symname, symname_len) != 0)
 884         continue;
 885       char c = archive_symname[symname_len];
 886       if (c == '\0' && sym->version() == NULL)
 887         return true;
 888       if (c == '@')
 889         {
 890           const char* ver = archive_symname + symname_len + 1;
 891           if (*ver == '@')
 892             {
 893               if (sym->version() == NULL)
 894                 return true;
 895               ++ver;
 896             }
 897           if (sym->version() != NULL && strcmp(sym->version(), ver) == 0)
 898             return true;
 899         }
 900     }
 901   return false;
 902 }
 903
 904 // Include all the archive members in the link.  This is for --whole-archive.
 905
 906 bool
 907 Archive::include_all_members(Symbol_table* symtab, Layout* layout,
 908                              Input_objects* input_objects, Mapfile* mapfile)
 909 {
 910   // Don't include the same archive twice.  This can happen if
 911   // --whole-archive is nested inside --start-group (PR gold/12163).
 912   if (this->included_all_members_)
 913     return true;
 914
 915   this->included_all_members_ = true;
 916
 917   input_objects->archive_start(this);
 918
 919   if (this->members_.size() > 0)
 920     {
 921       std::map<off_t, Archive_member>::const_iterator p;
 922       for (p = this->members_.begin();
 923            p != this->members_.end();
 924            ++p)
 925         {
 926           if (!this->include_member(symtab, layout, input_objects, p->first,
 927                                     mapfile, NULL, "--whole-archive"))
 928             return false;
 929           ++Archive::total_members;
 930         }
 931     }
 932   else
 933     {
 934       for (Archive::const_iterator p = this->begin();
 935            p != this->end();
 936            ++p)
 937         {
 938           if (!this->include_member(symtab, layout, input_objects, p->off,
 939                                     mapfile, NULL, "--whole-archive"))
 940             return false;
 941           ++Archive::total_members;
 942         }
 943     }
 944
 945   input_objects->archive_stop(this);
 946
 947   return true;
 948 }
 949
 950 // Return the number of members in the archive.  This is only used for
 951 // reports.
 952
 953 size_t
 954 Archive::count_members()
 955 {
 956   size_t ret = 0;
 957   for (Archive::const_iterator p = this->begin();
 958        p != this->end();
 959        ++p)
 960     ++ret;
 961   return ret;
 962 }
 963
 964 // RAII class to ensure we unlock the object if it's a member of a
 965 // thin archive. We can't use Task_lock_obj in Archive::include_member
 966 // because the object file is already locked when it's opened by
 967 // get_elf_object_for_member.
 968
 969 class Thin_archive_object_unlocker
 970 {
 971  public:
 972   Thin_archive_object_unlocker(const Task *task, Object* obj)
 973     : task_(task), obj_(obj)
 974   { }
 975
 976   ~Thin_archive_object_unlocker()
 977   {
 978     if (this->obj_->offset() == 0)
 979       this->obj_->unlock(this->task_);
 980   }
 981
 982  private:
 983   Thin_archive_object_unlocker(const Thin_archive_object_unlocker&);
 984   Thin_archive_object_unlocker& operator=(const Thin_archive_object_unlocker&);
 985
 986   const Task* task_;
 987   Object* obj_;
 988 };
 989
 990 // Include an archive member in the link.  OFF is the file offset of
 991 // the member header.  WHY is the reason we are including this member.
 992 // Return true if we added the member or if we had an error, return
 993 // false if this was the first member we tried to add from this
 994 // archive and it had an incompatible format.
 995
 996 bool
 997 Archive::include_member(Symbol_table* symtab, Layout* layout,
 998                         Input_objects* input_objects, off_t off,
 999                         Mapfile* mapfile, Symbol* sym, const char* why)
1000 {
1001   ++Archive::total_members_loaded;
1002
1003   std::map<off_t, Archive_member>::const_iterator p = this->members_.find(off);
1004   if (p != this->members_.end())
1005     {
1006       Object* obj = p->second.obj_;
1007
1008       Read_symbols_data* sd = p->second.sd_;
1009       if (mapfile != NULL)
1010         mapfile->report_include_archive_member(obj->name(), sym, why);
1011       if (input_objects->add_object(obj))
1012         {
1013           obj->layout(symtab, layout, sd);
1014           obj->add_symbols(symtab, sd, layout);
1015           this->included_member_ = true;
1016         }
1017       delete sd;
1018       return true;
1019     }
1020
1021   // If this is the first object we are including from this archive,
1022   // and we searched for this archive, most likely because it was
1023   // found via a -l option, then if the target is incompatible we want
1024   // to move on to the next archive found in the search path.
1025   bool unconfigured = false;
1026   bool* punconfigured = NULL;
1027   if (!this->included_member_ && this->searched_for())
1028     punconfigured = &unconfigured;
1029
1030   Object* obj = this->get_elf_object_for_member(off, punconfigured);
1031   if (obj == NULL)
1032     {
1033       // Return false to search for another archive, true if we found
1034       // an error.
1035       return unconfigured ? false : true;
1036     }
1037
1038   // If the object is an external member of a thin archive,
1039   // unlock it when we're done here.
1040   Thin_archive_object_unlocker unlocker(this->task_, obj);
1041
1042   if (mapfile != NULL)
1043     mapfile->report_include_archive_member(obj->name(), sym, why);
1044
1045   Pluginobj* pluginobj = obj->pluginobj();
1046   if (pluginobj != NULL)
1047     {
1048       pluginobj->add_symbols(symtab, NULL, layout);
1049       this->included_member_ = true;
1050       return true;
1051     }
1052
1053   if (!input_objects->add_object(obj))
1054     {
1055       delete obj;
1056       return true;
1057     }
1058
1059   if (layout->incremental_inputs() != NULL)
1060     layout->incremental_inputs()->report_object(obj, 0, this, NULL);
1061
1062   {
1063     Read_symbols_data sd;
1064     obj->read_symbols(&sd);
1065     obj->layout(symtab, layout, &sd);
1066     obj->add_symbols(symtab, &sd, layout);
1067   }
1068
1069   this->included_member_ = true;
1070   return true;
1071 }
1072
1073 // Iterate over all unused symbols, and call the visitor class V for each.
1074
1075 void
1076 Archive::do_for_all_unused_symbols(Symbol_visitor_base* v) const
1077 {
1078   for (std::vector<Armap_entry>::const_iterator p = this->armap_.begin();
1079        p != this->armap_.end();
1080        ++p)
1081     {
1082       if (this->seen_offsets_.find(p->file_offset)
1083           == this->seen_offsets_.end())
1084         v->visit(this->armap_names_.data() + p->name_offset);
1085     }
1086 }
1087
1088 // Print statistical information to stderr.  This is used for --stats.
1089
1090 void
1091 Archive::print_stats()
1092 {
1093   fprintf(stderr, _("%s: archive libraries: %u\n"),
1094           program_name, Archive::total_archives);
1095   fprintf(stderr, _("%s: total archive members: %u\n"),
1096           program_name, Archive::total_members);
1097   fprintf(stderr, _("%s: loaded archive members: %u\n"),
1098           program_name, Archive::total_members_loaded);
1099 }
1100
1101 // Add_archive_symbols methods.
1102
1103 Add_archive_symbols::~Add_archive_symbols()
1104 {
1105   if (this->this_blocker_ != NULL)
1106     delete this->this_blocker_;
1107   // next_blocker_ is deleted by the task associated with the next
1108   // input file.
1109 }
1110
1111 // Return whether we can add the archive symbols.  We are blocked by
1112 // this_blocker_.  We block next_blocker_.  We also lock the file.
1113
1114 Task_token*
1115 Add_archive_symbols::is_runnable()
1116 {
1117   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
1118     return this->this_blocker_;
1119   return NULL;
1120 }
1121
1122 void
1123 Add_archive_symbols::locks(Task_locker* tl)
1124 {
1125   tl->add(this, this->next_blocker_);
1126   tl->add(this, this->archive_->token());
1127 }
1128
1129 void
1130 Add_archive_symbols::run(Workqueue* workqueue)
1131 {
1132   // For an incremental link, begin recording layout information.
1133   Incremental_inputs* incremental_inputs = this->layout_->incremental_inputs();
1134   if (incremental_inputs != NULL)
1135     {
1136       unsigned int arg_serial = this->input_argument_->file().arg_serial();
1137       Script_info* script_info = this->input_argument_->script_info();
1138       incremental_inputs->report_archive_begin(this->archive_, arg_serial,
1139                                                script_info);
1140     }
1141
1142   bool added = this->archive_->add_symbols(this->symtab_, this->layout_,
1143                                            this->input_objects_,
1144                                            this->mapfile_);
1145   this->archive_->unlock_nested_archives();
1146
1147   this->archive_->release();
1148   this->archive_->clear_uncached_views();
1149
1150   if (!added)
1151     {
1152       // This archive holds object files which are incompatible with
1153       // our output file.
1154       Read_symbols::incompatible_warning(this->input_argument_,
1155                                          this->archive_->input_file());
1156       Read_symbols::requeue(workqueue, this->input_objects_, this->symtab_,
1157                             this->layout_, this->dirpath_, this->dirindex_,
1158                             this->mapfile_, this->input_argument_,
1159                             this->input_group_, this->next_blocker_);
1160       delete this->archive_;
1161       return;
1162     }
1163
1164   if (this->input_group_ != NULL)
1165     this->input_group_->add_archive(this->archive_);
1166   else
1167     {
1168       // For an incremental link, finish recording the layout information.
1169       if (incremental_inputs != NULL)
1170         incremental_inputs->report_archive_end(this->archive_);
1171
1172       if (!parameters->options().has_plugins()
1173           || this->archive_->input_file()->options().whole_archive())
1174         {
1175           // We no longer need to know about this archive.
1176           delete this->archive_;
1177         }
1178       else
1179         {
1180           // The plugin interface may want to rescan this archive.
1181           parameters->options().plugins()->save_archive(this->archive_);
1182         }
1183
1184       this->archive_ = NULL;
1185     }
1186 }
1187
1188 // Class Lib_group static variables.
1189 unsigned int Lib_group::total_lib_groups;
1190 unsigned int Lib_group::total_members;
1191 unsigned int Lib_group::total_members_loaded;
1192
1193 Lib_group::Lib_group(const Input_file_lib* lib, Task* task)
1194   : Library_base(task), members_()
1195 {
1196   this->members_.resize(lib->size());
1197 }
1198
1199 const std::string&
1200 Lib_group::do_filename() const
1201 {
1202   std::string *filename = new std::string("/group/");
1203   return *filename;
1204 }
1205
1206 // Select members from the lib group and add them to the link.  We walk
1207 // through the members, and check if each one up should be included.
1208 // If the object says it should be included, we do so.  We have to do
1209 // this in a loop, since including one member may create new undefined
1210 // symbols which may be satisfied by other members.
1211
1212 void
1213 Lib_group::add_symbols(Symbol_table* symtab, Layout* layout,
1214                        Input_objects* input_objects)
1215 {
1216   ++Lib_group::total_lib_groups;
1217
1218   Lib_group::total_members += this->members_.size();
1219
1220   bool added_new_object;
1221   do
1222     {
1223       added_new_object = false;
1224       unsigned int i = 0;
1225       while (i < this->members_.size())
1226         {
1227           const Archive_member& member = this->members_[i];
1228           Object* obj = member.obj_;
1229           std::string why;
1230
1231           // Skip files with no symbols. Plugin objects have
1232           // member.sd_ == NULL.
1233           if (obj != NULL
1234               && (member.sd_ == NULL || member.sd_->symbol_names != NULL))
1235             {
1236               Archive::Should_include t = obj->should_include_member(symtab,
1237                                                                      layout,
1238                                                                      member.sd_,
1239                                                                      &why);
1240
1241               if (t != Archive::SHOULD_INCLUDE_YES)
1242                 {
1243                   ++i;
1244                   continue;
1245                 }
1246
1247               this->include_member(symtab, layout, input_objects, member);
1248
1249               added_new_object = true;
1250             }
1251           else
1252             {
1253               if (member.sd_ != NULL)
1254                 {
1255                   // The file must be locked in order to destroy the views
1256                   // associated with it.
1257                   gold_assert(obj != NULL);
1258                   obj->lock(this->task_);
1259                   delete member.sd_;
1260                   obj->unlock(this->task_);
1261                 }
1262             }
1263
1264           this->members_[i] = this->members_.back();
1265           this->members_.pop_back();
1266         }
1267     }
1268   while (added_new_object);
1269 }
1270
1271 // Include a lib group member in the link.
1272
1273 void
1274 Lib_group::include_member(Symbol_table* symtab, Layout* layout,
1275                           Input_objects* input_objects,
1276                           const Archive_member& member)
1277 {
1278   ++Lib_group::total_members_loaded;
1279
1280   Object* obj = member.obj_;
1281   gold_assert(obj != NULL);
1282
1283   Pluginobj* pluginobj = obj->pluginobj();
1284   if (pluginobj != NULL)
1285     {
1286       pluginobj->add_symbols(symtab, NULL, layout);
1287       return;
1288     }
1289
1290   Read_symbols_data* sd = member.sd_;
1291   gold_assert(sd != NULL);
1292   obj->lock(this->task_);
1293   if (input_objects->add_object(obj))
1294     {
1295       if (layout->incremental_inputs() != NULL)
1296         layout->incremental_inputs()->report_object(obj, member.arg_serial_,
1297                                                     this, NULL);
1298       obj->layout(symtab, layout, sd);
1299       obj->add_symbols(symtab, sd, layout);
1300     }
1301   delete sd;
1302   // Unlock the file for the next task.
1303   obj->unlock(this->task_);
1304 }
1305
1306 // Iterate over all unused symbols, and call the visitor class V for each.
1307
1308 void
1309 Lib_group::do_for_all_unused_symbols(Symbol_visitor_base* v) const
1310 {
1311   // Files are removed from the members list when used, so all the
1312   // files remaining on the list are unused.
1313   for (std::vector<Archive_member>::const_iterator p = this->members_.begin();
1314        p != this->members_.end();
1315        ++p)
1316     {
1317       Object* obj = p->obj_;
1318       obj->for_all_global_symbols(p->sd_, v);
1319     }
1320 }
1321
1322 // Print statistical information to stderr.  This is used for --stats.
1323
1324 void
1325 Lib_group::print_stats()
1326 {
1327   fprintf(stderr, _("%s: lib groups: %u\n"),
1328           program_name, Lib_group::total_lib_groups);
1329   fprintf(stderr, _("%s: total lib groups members: %u\n"),
1330           program_name, Lib_group::total_members);
1331   fprintf(stderr, _("%s: loaded lib groups members: %u\n"),
1332           program_name, Lib_group::total_members_loaded);
1333 }
1334
1335 Task_token*
1336 Add_lib_group_symbols::is_runnable()
1337 {
1338   if (this->readsyms_blocker_ != NULL && this->readsyms_blocker_->is_blocked())
1339     return this->readsyms_blocker_;
1340   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
1341     return this->this_blocker_;
1342   return NULL;
1343 }
1344
1345 void
1346 Add_lib_group_symbols::locks(Task_locker* tl)
1347 {
1348   tl->add(this, this->next_blocker_);
1349 }
1350
1351 void
1352 Add_lib_group_symbols::run(Workqueue*)
1353 {
1354   // For an incremental link, begin recording layout information.
1355   Incremental_inputs* incremental_inputs = this->layout_->incremental_inputs();
1356   if (incremental_inputs != NULL)
1357     incremental_inputs->report_archive_begin(this->lib_, 0, NULL);
1358
1359   this->lib_->add_symbols(this->symtab_, this->layout_, this->input_objects_);
1360
1361   if (incremental_inputs != NULL)
1362     incremental_inputs->report_archive_end(this->lib_);
1363 }
1364
1365 Add_lib_group_symbols::~Add_lib_group_symbols()
1366 {
1367   if (this->this_blocker_ != NULL)
1368     delete this->this_blocker_;
1369   // next_blocker_ is deleted by the task associated with the next
1370   // input file.
1371 }
1372
1373 } // End namespace gold.