gold/archive.cc

   1 // archive.cc -- archive support for gold
   2
   3 // Copyright (C) 2006-2015 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 Archive::Archive(const std::string& name, Input_file* input_file,
 197                  bool is_thin_archive, Dirsearch* dirpath, Task* task)
 198   : Library_base(task), name_(name), input_file_(input_file), armap_(),
 199     armap_names_(), extended_names_(), armap_checked_(), seen_offsets_(),
 200     members_(), is_thin_archive_(is_thin_archive), included_member_(false),
 201     nested_archives_(), dirpath_(dirpath), num_members_(0),
 202     included_all_members_(false)
 203 {
 204   this->no_export_ =
 205     parameters->options().check_excluded_libs(input_file->found_name());
 206 }
 207
 208 // Set up the archive: read the symbol map and the extended name
 209 // table.
 210
 211 void
 212 Archive::setup()
 213 {
 214   // We need to ignore empty archives.
 215   if (this->input_file_->file().filesize() == sarmag)
 216     return;
 217
 218   // The first member of the archive should be the symbol table.
 219   std::string armap_name;
 220   off_t header_size = this->read_header(sarmag, false, &armap_name, NULL);
 221   if (header_size == -1)
 222     return;
 223
 224   section_size_type armap_size = convert_to_section_size_type(header_size);
 225   off_t off = sarmag;
 226   if (armap_name.empty())
 227     {
 228       this->read_armap(sarmag + sizeof(Archive_header), armap_size);
 229       off = sarmag + sizeof(Archive_header) + armap_size;
 230     }
 231   else if (!this->input_file_->options().whole_archive())
 232     gold_error(_("%s: no archive symbol table (run ranlib)"),
 233                this->name().c_str());
 234
 235   // See if there is an extended name table.  We cache these views
 236   // because it is likely that we will want to read the following
 237   // header in the add_symbols routine.
 238   if ((off & 1) != 0)
 239     ++off;
 240   std::string xname;
 241   header_size = this->read_header(off, true, &xname, NULL);
 242   if (header_size == -1)
 243     return;
 244
 245   section_size_type extended_size = convert_to_section_size_type(header_size);
 246   if (xname == "/")
 247     {
 248       const unsigned char* p = this->get_view(off + sizeof(Archive_header),
 249                                               extended_size, false, true);
 250       const char* px = reinterpret_cast<const char*>(p);
 251       this->extended_names_.assign(px, extended_size);
 252     }
 253   bool preread_syms = (parameters->options().threads()
 254                        && parameters->options().preread_archive_symbols());
 255 #ifndef ENABLE_THREADS
 256   preread_syms = false;
 257 #else
 258   if (parameters->options().has_plugins())
 259     preread_syms = false;
 260 #endif
 261   if (preread_syms)
 262     this->read_all_symbols();
 263 }
 264
 265 // Unlock any nested archives.
 266
 267 void
 268 Archive::unlock_nested_archives()
 269 {
 270   for (Nested_archive_table::iterator p = this->nested_archives_.begin();
 271        p != this->nested_archives_.end();
 272        ++p)
 273     {
 274       p->second->unlock(this->task_);
 275     }
 276 }
 277
 278 // Read the archive symbol map.
 279
 280 void
 281 Archive::read_armap(off_t start, section_size_type size)
 282 {
 283   // To count the total number of archive members, we'll just count
 284   // the number of times the file offset changes.  Since most archives
 285   // group the symbols in the armap by object, this ought to give us
 286   // an accurate count.
 287   off_t last_seen_offset = -1;
 288
 289   // Read in the entire armap.
 290   const unsigned char* p = this->get_view(start, size, true, false);
 291
 292   // Numbers in the armap are always big-endian.
 293   const elfcpp::Elf_Word* pword = reinterpret_cast<const elfcpp::Elf_Word*>(p);
 294   unsigned int nsyms = elfcpp::Swap<32, true>::readval(pword);
 295   ++pword;
 296
 297   // Note that the addition is in units of sizeof(elfcpp::Elf_Word).
 298   const char* pnames = reinterpret_cast<const char*>(pword + nsyms);
 299   section_size_type names_size =
 300     reinterpret_cast<const char*>(p) + size - pnames;
 301   this->armap_names_.assign(pnames, names_size);
 302
 303   this->armap_.resize(nsyms);
 304
 305   section_offset_type name_offset = 0;
 306   for (unsigned int i = 0; i < nsyms; ++i)
 307     {
 308       this->armap_[i].name_offset = name_offset;
 309       this->armap_[i].file_offset = elfcpp::Swap<32, true>::readval(pword);
 310       name_offset += strlen(pnames + name_offset) + 1;
 311       ++pword;
 312       if (this->armap_[i].file_offset != last_seen_offset)
 313         {
 314           last_seen_offset = this->armap_[i].file_offset;
 315           ++this->num_members_;
 316         }
 317     }
 318
 319   if (static_cast<section_size_type>(name_offset) > names_size)
 320     gold_error(_("%s: bad archive symbol table names"),
 321                this->name().c_str());
 322
 323   // This array keeps track of which symbols are for archive elements
 324   // which we have already included in the link.
 325   this->armap_checked_.resize(nsyms);
 326 }
 327
 328 // Read the header of an archive member at OFF.  Fail if something
 329 // goes wrong.  Return the size of the member.  Set *PNAME to the name
 330 // of the member.
 331
 332 off_t
 333 Archive::read_header(off_t off, bool cache, std::string* pname,
 334                      off_t* nested_off)
 335 {
 336   const unsigned char* p = this->get_view(off, sizeof(Archive_header), true,
 337                                           cache);
 338   const Archive_header* hdr = reinterpret_cast<const Archive_header*>(p);
 339   return this->interpret_header(hdr, off,  pname, nested_off);
 340 }
 341
 342 // Interpret the header of HDR, the header of the archive member at
 343 // file offset OFF.  Return the size of the member, or -1 if something
 344 // has gone wrong.  Set *PNAME to the name of the member.
 345
 346 off_t
 347 Archive::interpret_header(const Archive_header* hdr, off_t off,
 348                           std::string* pname, off_t* nested_off) const
 349 {
 350   if (memcmp(hdr->ar_fmag, arfmag, sizeof arfmag) != 0)
 351     {
 352       gold_error(_("%s: malformed archive header at %zu"),
 353                  this->name().c_str(), static_cast<size_t>(off));
 354       return -1;
 355     }
 356
 357   const int size_string_size = sizeof hdr->ar_size;
 358   char size_string[size_string_size + 1];
 359   memcpy(size_string, hdr->ar_size, size_string_size);
 360   char* ps = size_string + size_string_size;
 361   while (ps[-1] == ' ')
 362     --ps;
 363   *ps = '\0';
 364
 365   errno = 0;
 366   char* end;
 367   off_t member_size = strtol(size_string, &end, 10);
 368   if (*end != '\0'
 369       || member_size < 0
 370       || (member_size == LONG_MAX && errno == ERANGE))
 371     {
 372       gold_error(_("%s: malformed archive header size at %zu"),
 373                  this->name().c_str(), static_cast<size_t>(off));
 374       return -1;
 375     }
 376
 377   if (hdr->ar_name[0] != '/')
 378     {
 379       const char* name_end = strchr(hdr->ar_name, '/');
 380       if (name_end == NULL
 381           || name_end - hdr->ar_name >= static_cast<int>(sizeof hdr->ar_name))
 382         {
 383           gold_error(_("%s: malformed archive header name at %zu"),
 384                      this->name().c_str(), static_cast<size_t>(off));
 385           return -1;
 386         }
 387       pname->assign(hdr->ar_name, name_end - hdr->ar_name);
 388       if (nested_off != NULL)
 389         *nested_off = 0;
 390     }
 391   else if (hdr->ar_name[1] == ' ')
 392     {
 393       // This is the symbol table.
 394       if (!pname->empty())
 395         pname->clear();
 396     }
 397   else if (hdr->ar_name[1] == '/')
 398     {
 399       // This is the extended name table.
 400       pname->assign(1, '/');
 401     }
 402   else
 403     {
 404       errno = 0;
 405       long x = strtol(hdr->ar_name + 1, &end, 10);
 406       long y = 0;
 407       if (*end == ':')
 408         y = strtol(end + 1, &end, 10);
 409       if (*end != ' '
 410           || x < 0
 411           || (x == LONG_MAX && errno == ERANGE)
 412           || static_cast<size_t>(x) >= this->extended_names_.size())
 413         {
 414           gold_error(_("%s: bad extended name index at %zu"),
 415                      this->name().c_str(), static_cast<size_t>(off));
 416           return -1;
 417         }
 418
 419       const char* name = this->extended_names_.data() + x;
 420       const char* name_end = strchr(name, '\n');
 421       if (static_cast<size_t>(name_end - name) > this->extended_names_.size()
 422           || name_end[-1] != '/')
 423         {
 424           gold_error(_("%s: bad extended name entry at header %zu"),
 425                      this->name().c_str(), static_cast<size_t>(off));
 426           return -1;
 427         }
 428       pname->assign(name, name_end - 1 - name);
 429       if (nested_off != NULL)
 430         *nested_off = y;
 431     }
 432
 433   return member_size;
 434 }
 435
 436 // An archive member iterator.
 437
 438 class Archive::const_iterator
 439 {
 440  public:
 441   // The header of an archive member.  This is what this iterator
 442   // points to.
 443   struct Header
 444   {
 445     // The name of the member.
 446     std::string name;
 447     // The file offset of the member.
 448     off_t off;
 449     // The file offset of a nested archive member.
 450     off_t nested_off;
 451     // The size of the member.
 452     off_t size;
 453   };
 454
 455   const_iterator(Archive* archive, off_t off)
 456     : archive_(archive), off_(off)
 457   { this->read_next_header(); }
 458
 459   const Header&
 460   operator*() const
 461   { return this->header_; }
 462
 463   const Header*
 464   operator->() const
 465   { return &this->header_; }
 466
 467   const_iterator&
 468   operator++()
 469   {
 470     if (this->off_ == this->archive_->file().filesize())
 471       return *this;
 472     this->off_ += sizeof(Archive_header);
 473     if (!this->archive_->is_thin_archive())
 474       this->off_ += this->header_.size;
 475     if ((this->off_ & 1) != 0)
 476       ++this->off_;
 477     this->read_next_header();
 478     return *this;
 479   }
 480
 481   const_iterator
 482   operator++(int)
 483   {
 484     const_iterator ret = *this;
 485     ++*this;
 486     return ret;
 487   }
 488
 489   bool
 490   operator==(const const_iterator p) const
 491   { return this->off_ == p->off; }
 492
 493   bool
 494   operator!=(const const_iterator p) const
 495   { return this->off_ != p->off; }
 496
 497  private:
 498   void
 499   read_next_header();
 500
 501   // The underlying archive.
 502   Archive* archive_;
 503   // The current offset in the file.
 504   off_t off_;
 505   // The current archive header.
 506   Header header_;
 507 };
 508
 509 // Read the next archive header.
 510
 511 void
 512 Archive::const_iterator::read_next_header()
 513 {
 514   off_t filesize = this->archive_->file().filesize();
 515   while (true)
 516     {
 517       if (filesize - this->off_ < static_cast<off_t>(sizeof(Archive_header)))
 518         {
 519           if (filesize != this->off_)
 520             {
 521               gold_error(_("%s: short archive header at %zu"),
 522                          this->archive_->filename().c_str(),
 523                          static_cast<size_t>(this->off_));
 524               this->off_ = filesize;
 525             }
 526           this->header_.off = filesize;
 527           return;
 528         }
 529
 530       unsigned char buf[sizeof(Archive_header)];
 531       this->archive_->file().read(this->off_, sizeof(Archive_header), buf);
 532
 533       const Archive_header* hdr = reinterpret_cast<const Archive_header*>(buf);
 534       off_t size = this->archive_->interpret_header(hdr, this->off_,
 535                                                     &this->header_.name,
 536                                                     &this->header_.nested_off);
 537       if (size == -1)
 538         {
 539           this->header_.off = filesize;
 540           return;
 541         }
 542
 543       this->header_.size = size;
 544       this->header_.off = this->off_;
 545
 546       // Skip special members.
 547       if (!this->header_.name.empty() && this->header_.name != "/")
 548         return;
 549
 550       this->off_ += sizeof(Archive_header) + this->header_.size;
 551       if ((this->off_ & 1) != 0)
 552         ++this->off_;
 553     }
 554 }
 555
 556 // Initial iterator.
 557
 558 Archive::const_iterator
 559 Archive::begin()
 560 {
 561   return Archive::const_iterator(this, sarmag);
 562 }
 563
 564 // Final iterator.
 565
 566 Archive::const_iterator
 567 Archive::end()
 568 {
 569   return Archive::const_iterator(this, this->input_file_->file().filesize());
 570 }
 571
 572 // Get the file and offset for an archive member, which may be an
 573 // external member of a thin archive.  Set *INPUT_FILE to the
 574 // file containing the actual member, *MEMOFF to the offset
 575 // within that file (0 if not a nested archive), and *MEMBER_NAME
 576 // to the name of the archive member.  Return TRUE on success.
 577
 578 bool
 579 Archive::get_file_and_offset(off_t off, Input_file** input_file, off_t* memoff,
 580                              off_t* memsize, std::string* member_name)
 581 {
 582   off_t nested_off;
 583
 584   *memsize = this->read_header(off, false, member_name, &nested_off);
 585   if (*memsize == -1)
 586     return false;
 587
 588   *input_file = this->input_file_;
 589   *memoff = off + static_cast<off_t>(sizeof(Archive_header));
 590
 591   if (!this->is_thin_archive_)
 592     return true;
 593
 594   // Adjust a relative pathname so that it is relative
 595   // to the directory containing the archive.
 596   if (!IS_ABSOLUTE_PATH(member_name->c_str()))
 597     {
 598       const char* arch_path = this->filename().c_str();
 599       const char* basename = lbasename(arch_path);
 600       if (basename > arch_path)
 601         member_name->replace(0, 0,
 602                              this->filename().substr(0, basename - arch_path));
 603     }
 604
 605   if (nested_off > 0)
 606     {
 607       // This is a member of a nested archive.  Open the containing
 608       // archive if we don't already have it open, then do a recursive
 609       // call to include the member from that archive.
 610       Archive* arch;
 611       Nested_archive_table::const_iterator p =
 612         this->nested_archives_.find(*member_name);
 613       if (p != this->nested_archives_.end())
 614         arch = p->second;
 615       else
 616         {
 617           Input_file_argument* input_file_arg =
 618             new Input_file_argument(member_name->c_str(),
 619                                     Input_file_argument::INPUT_FILE_TYPE_FILE,
 620                                     "", false, parameters->options());
 621           *input_file = new Input_file(input_file_arg);
 622           int dummy = 0;
 623           if (!(*input_file)->open(*this->dirpath_, this->task_, &dummy))
 624             return false;
 625           arch = new Archive(*member_name, *input_file, false, this->dirpath_,
 626                              this->task_);
 627           arch->setup();
 628           std::pair<Nested_archive_table::iterator, bool> ins =
 629             this->nested_archives_.insert(std::make_pair(*member_name, arch));
 630           gold_assert(ins.second);
 631         }
 632       return arch->get_file_and_offset(nested_off, input_file, memoff,
 633                                        memsize, member_name);
 634     }
 635
 636   // This is an external member of a thin archive.  Open the
 637   // file as a regular relocatable object file.
 638   Input_file_argument* input_file_arg =
 639       new Input_file_argument(member_name->c_str(),
 640                               Input_file_argument::INPUT_FILE_TYPE_FILE,
 641                               "", false, this->input_file_->options());
 642   *input_file = new Input_file(input_file_arg);
 643   int dummy = 0;
 644   if (!(*input_file)->open(*this->dirpath_, this->task_, &dummy))
 645     return false;
 646
 647   *memoff = 0;
 648   *memsize = (*input_file)->file().filesize();
 649   return true;
 650 }
 651
 652 // Return an ELF object for the member at offset OFF.  If
 653 // PUNCONFIGURED is not NULL, then if the ELF object has an
 654 // unsupported target type, set *PUNCONFIGURED to true and return
 655 // NULL.
 656
 657 Object*
 658 Archive::get_elf_object_for_member(off_t off, bool* punconfigured)
 659 {
 660   if (punconfigured != NULL)
 661     *punconfigured = false;
 662
 663   Input_file* input_file;
 664   off_t memoff;
 665   off_t memsize;
 666   std::string member_name;
 667   if (!this->get_file_and_offset(off, &input_file, &memoff, &memsize,
 668                                  &member_name))
 669     return NULL;
 670
 671   const unsigned char* ehdr;
 672   int read_size;
 673   Object *obj = NULL;
 674   bool is_elf_obj = false;
 675
 676   if (is_elf_object(input_file, memoff, &ehdr, &read_size))
 677     {
 678       obj = make_elf_object((std::string(this->input_file_->filename())
 679                              + "(" + member_name + ")"),
 680                             input_file, memoff, ehdr, read_size,
 681                             punconfigured);
 682       is_elf_obj = true;
 683     }
 684
 685   if (parameters->options().has_plugins())
 686     {
 687       Object* plugin_obj
 688         = parameters->options().plugins()->claim_file(input_file,
 689                                                       memoff,
 690                                                       memsize,
 691                                                       obj);
 692       if (plugin_obj != NULL)
 693         {
 694           // The input file was claimed by a plugin, and its symbols
 695           // have been provided by the plugin.
 696           // Delete its elf object.
 697           if (obj != NULL)
 698             delete obj;
 699           return plugin_obj;
 700         }
 701     }
 702
 703   if (!is_elf_obj)
 704     {
 705       gold_error(_("%s: member at %zu is not an ELF object"),
 706                  this->name().c_str(), static_cast<size_t>(off));
 707       return NULL;
 708     }
 709
 710   if (obj == NULL)
 711     return NULL;
 712   obj->set_no_export(this->no_export());
 713   return obj;
 714 }
 715
 716 // Read the symbols from all the archive members in the link.
 717
 718 void
 719 Archive::read_all_symbols()
 720 {
 721   for (Archive::const_iterator p = this->begin();
 722        p != this->end();
 723        ++p)
 724     this->read_symbols(p->off);
 725 }
 726
 727 // Read the symbols from an archive member in the link.  OFF is the file
 728 // offset of the member header.
 729
 730 void
 731 Archive::read_symbols(off_t off)
 732 {
 733   Object* obj = this->get_elf_object_for_member(off, NULL);
 734   if (obj == NULL)
 735     return;
 736
 737   Read_symbols_data* sd = new Read_symbols_data;
 738   obj->read_symbols(sd);
 739   Archive_member member(obj, sd);
 740   this->members_[off] = member;
 741 }
 742
 743 // Select members from the archive and add them to the link.  We walk
 744 // through the elements in the archive map, and look each one up in
 745 // the symbol table.  If it exists as a strong undefined symbol, we
 746 // pull in the corresponding element.  We have to do this in a loop,
 747 // since pulling in one element may create new undefined symbols which
 748 // may be satisfied by other objects in the archive.  Return true in
 749 // the normal case, false if the first member we tried to add from
 750 // this archive had an incompatible target.
 751
 752 bool
 753 Archive::add_symbols(Symbol_table* symtab, Layout* layout,
 754                      Input_objects* input_objects, Mapfile* mapfile)
 755 {
 756   ++Archive::total_archives;
 757
 758   if (this->input_file_->options().whole_archive())
 759     return this->include_all_members(symtab, layout, input_objects,
 760                                      mapfile);
 761
 762   Archive::total_members += this->num_members_;
 763
 764   input_objects->archive_start(this);
 765
 766   const size_t armap_size = this->armap_.size();
 767
 768   // This is a quick optimization, since we usually see many symbols
 769   // in a row with the same offset.  last_seen_offset holds the last
 770   // offset we saw that was present in the seen_offsets_ set.
 771   off_t last_seen_offset = -1;
 772
 773   // Track which symbols in the symbol table we've already found to be
 774   // defined.
 775
 776   char* tmpbuf = NULL;
 777   size_t tmpbuflen = 0;
 778   bool added_new_object;
 779   do
 780     {
 781       added_new_object = false;
 782       for (size_t i = 0; i < armap_size; ++i)
 783         {
 784           if (this->armap_checked_[i])
 785             continue;
 786           if (this->armap_[i].file_offset == last_seen_offset)
 787             {
 788               this->armap_checked_[i] = true;
 789               continue;
 790             }
 791           if (this->seen_offsets_.find(this->armap_[i].file_offset)
 792               != this->seen_offsets_.end())
 793             {
 794               this->armap_checked_[i] = true;
 795               last_seen_offset = this->armap_[i].file_offset;
 796               continue;
 797             }
 798
 799           const char* sym_name = (this->armap_names_.data()
 800                                   + this->armap_[i].name_offset);
 801
 802           Symbol* sym;
 803           std::string why;
 804           Archive::Should_include t =
 805             Archive::should_include_member(symtab, layout, sym_name, &sym,
 806                                            &why, &tmpbuf, &tmpbuflen);
 807
 808           if (t == Archive::SHOULD_INCLUDE_NO
 809               || t == Archive::SHOULD_INCLUDE_YES)
 810             this->armap_checked_[i] = true;
 811
 812           if (t != Archive::SHOULD_INCLUDE_YES)
 813             continue;
 814
 815           // We want to include this object in the link.
 816           last_seen_offset = this->armap_[i].file_offset;
 817           this->seen_offsets_.insert(last_seen_offset);
 818
 819           if (!this->include_member(symtab, layout, input_objects,
 820                                     last_seen_offset, mapfile, sym,
 821                                     why.c_str()))
 822             {
 823               if (tmpbuf != NULL)
 824                 free(tmpbuf);
 825               return false;
 826             }
 827
 828           added_new_object = true;
 829         }
 830     }
 831   while (added_new_object);
 832
 833   if (tmpbuf != NULL)
 834     free(tmpbuf);
 835
 836   input_objects->archive_stop(this);
 837
 838   return true;
 839 }
 840
 841 // Return whether the archive includes a member which defines the
 842 // symbol SYM.
 843
 844 bool
 845 Archive::defines_symbol(Symbol* sym) const
 846 {
 847   const char* symname = sym->name();
 848   size_t symname_len = strlen(symname);
 849   size_t armap_size = this->armap_.size();
 850   for (size_t i = 0; i < armap_size; ++i)
 851     {
 852       if (this->armap_checked_[i])
 853         continue;
 854       const char* archive_symname = (this->armap_names_.data()
 855                                      + this->armap_[i].name_offset);
 856       if (strncmp(archive_symname, symname, symname_len) != 0)
 857         continue;
 858       char c = archive_symname[symname_len];
 859       if (c == '\0' && sym->version() == NULL)
 860         return true;
 861       if (c == '@')
 862         {
 863           const char* ver = archive_symname + symname_len + 1;
 864           if (*ver == '@')
 865             {
 866               if (sym->version() == NULL)
 867                 return true;
 868               ++ver;
 869             }
 870           if (sym->version() != NULL && strcmp(sym->version(), ver) == 0)
 871             return true;
 872         }
 873     }
 874   return false;
 875 }
 876
 877 // Include all the archive members in the link.  This is for --whole-archive.
 878
 879 bool
 880 Archive::include_all_members(Symbol_table* symtab, Layout* layout,
 881                              Input_objects* input_objects, Mapfile* mapfile)
 882 {
 883   // Don't include the same archive twice.  This can happen if
 884   // --whole-archive is nested inside --start-group (PR gold/12163).
 885   if (this->included_all_members_)
 886     return true;
 887
 888   this->included_all_members_ = true;
 889
 890   input_objects->archive_start(this);
 891
 892   if (this->members_.size() > 0)
 893     {
 894       std::map<off_t, Archive_member>::const_iterator p;
 895       for (p = this->members_.begin();
 896            p != this->members_.end();
 897            ++p)
 898         {
 899           if (!this->include_member(symtab, layout, input_objects, p->first,
 900                                     mapfile, NULL, "--whole-archive"))
 901             return false;
 902           ++Archive::total_members;
 903         }
 904     }
 905   else
 906     {
 907       for (Archive::const_iterator p = this->begin();
 908            p != this->end();
 909            ++p)
 910         {
 911           if (!this->include_member(symtab, layout, input_objects, p->off,
 912                                     mapfile, NULL, "--whole-archive"))
 913             return false;
 914           ++Archive::total_members;
 915         }
 916     }
 917
 918   input_objects->archive_stop(this);
 919
 920   return true;
 921 }
 922
 923 // Return the number of members in the archive.  This is only used for
 924 // reports.
 925
 926 size_t
 927 Archive::count_members()
 928 {
 929   size_t ret = 0;
 930   for (Archive::const_iterator p = this->begin();
 931        p != this->end();
 932        ++p)
 933     ++ret;
 934   return ret;
 935 }
 936
 937 // RAII class to ensure we unlock the object if it's a member of a
 938 // thin archive. We can't use Task_lock_obj in Archive::include_member
 939 // because the object file is already locked when it's opened by
 940 // get_elf_object_for_member.
 941
 942 class Thin_archive_object_unlocker
 943 {
 944  public:
 945   Thin_archive_object_unlocker(const Task *task, Object* obj)
 946     : task_(task), obj_(obj)
 947   { }
 948
 949   ~Thin_archive_object_unlocker()
 950   {
 951     if (this->obj_->offset() == 0)
 952       this->obj_->unlock(this->task_);
 953   }
 954
 955  private:
 956   Thin_archive_object_unlocker(const Thin_archive_object_unlocker&);
 957   Thin_archive_object_unlocker& operator=(const Thin_archive_object_unlocker&);
 958
 959   const Task* task_;
 960   Object* obj_;
 961 };
 962
 963 // Include an archive member in the link.  OFF is the file offset of
 964 // the member header.  WHY is the reason we are including this member.
 965 // Return true if we added the member or if we had an error, return
 966 // false if this was the first member we tried to add from this
 967 // archive and it had an incompatible format.
 968
 969 bool
 970 Archive::include_member(Symbol_table* symtab, Layout* layout,
 971                         Input_objects* input_objects, off_t off,
 972                         Mapfile* mapfile, Symbol* sym, const char* why)
 973 {
 974   ++Archive::total_members_loaded;
 975
 976   std::map<off_t, Archive_member>::const_iterator p = this->members_.find(off);
 977   if (p != this->members_.end())
 978     {
 979       Object* obj = p->second.obj_;
 980
 981       Read_symbols_data* sd = p->second.sd_;
 982       if (mapfile != NULL)
 983         mapfile->report_include_archive_member(obj->name(), sym, why);
 984       if (input_objects->add_object(obj))
 985         {
 986           obj->layout(symtab, layout, sd);
 987           obj->add_symbols(symtab, sd, layout);
 988           this->included_member_ = true;
 989         }
 990       delete sd;
 991       return true;
 992     }
 993
 994   // If this is the first object we are including from this archive,
 995   // and we searched for this archive, most likely because it was
 996   // found via a -l option, then if the target is incompatible we want
 997   // to move on to the next archive found in the search path.
 998   bool unconfigured = false;
 999   bool* punconfigured = NULL;
1000   if (!this->included_member_ && this->searched_for())
1001     punconfigured = &unconfigured;
1002
1003   Object* obj = this->get_elf_object_for_member(off, punconfigured);
1004   if (obj == NULL)
1005     {
1006       // Return false to search for another archive, true if we found
1007       // an error.
1008       return unconfigured ? false : true;
1009     }
1010
1011   // If the object is an external member of a thin archive,
1012   // unlock it when we're done here.
1013   Thin_archive_object_unlocker unlocker(this->task_, obj);
1014
1015   if (mapfile != NULL)
1016     mapfile->report_include_archive_member(obj->name(), sym, why);
1017
1018   Pluginobj* pluginobj = obj->pluginobj();
1019   if (pluginobj != NULL)
1020     {
1021       pluginobj->add_symbols(symtab, NULL, layout);
1022       this->included_member_ = true;
1023       return true;
1024     }
1025
1026   if (!input_objects->add_object(obj))
1027     {
1028       delete obj;
1029       return true;
1030     }
1031
1032   if (layout->incremental_inputs() != NULL)
1033     layout->incremental_inputs()->report_object(obj, 0, this, NULL);
1034
1035   {
1036     Read_symbols_data sd;
1037     obj->read_symbols(&sd);
1038     obj->layout(symtab, layout, &sd);
1039     obj->add_symbols(symtab, &sd, layout);
1040   }
1041
1042   this->included_member_ = true;
1043   return true;
1044 }
1045
1046 // Iterate over all unused symbols, and call the visitor class V for each.
1047
1048 void
1049 Archive::do_for_all_unused_symbols(Symbol_visitor_base* v) const
1050 {
1051   for (std::vector<Armap_entry>::const_iterator p = this->armap_.begin();
1052        p != this->armap_.end();
1053        ++p)
1054     {
1055       if (this->seen_offsets_.find(p->file_offset)
1056           == this->seen_offsets_.end())
1057         v->visit(this->armap_names_.data() + p->name_offset);
1058     }
1059 }
1060
1061 // Print statistical information to stderr.  This is used for --stats.
1062
1063 void
1064 Archive::print_stats()
1065 {
1066   fprintf(stderr, _("%s: archive libraries: %u\n"),
1067           program_name, Archive::total_archives);
1068   fprintf(stderr, _("%s: total archive members: %u\n"),
1069           program_name, Archive::total_members);
1070   fprintf(stderr, _("%s: loaded archive members: %u\n"),
1071           program_name, Archive::total_members_loaded);
1072 }
1073
1074 // Add_archive_symbols methods.
1075
1076 Add_archive_symbols::~Add_archive_symbols()
1077 {
1078   if (this->this_blocker_ != NULL)
1079     delete this->this_blocker_;
1080   // next_blocker_ is deleted by the task associated with the next
1081   // input file.
1082 }
1083
1084 // Return whether we can add the archive symbols.  We are blocked by
1085 // this_blocker_.  We block next_blocker_.  We also lock the file.
1086
1087 Task_token*
1088 Add_archive_symbols::is_runnable()
1089 {
1090   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
1091     return this->this_blocker_;
1092   return NULL;
1093 }
1094
1095 void
1096 Add_archive_symbols::locks(Task_locker* tl)
1097 {
1098   tl->add(this, this->next_blocker_);
1099   tl->add(this, this->archive_->token());
1100 }
1101
1102 void
1103 Add_archive_symbols::run(Workqueue* workqueue)
1104 {
1105   // For an incremental link, begin recording layout information.
1106   Incremental_inputs* incremental_inputs = this->layout_->incremental_inputs();
1107   if (incremental_inputs != NULL)
1108     {
1109       unsigned int arg_serial = this->input_argument_->file().arg_serial();
1110       Script_info* script_info = this->input_argument_->script_info();
1111       incremental_inputs->report_archive_begin(this->archive_, arg_serial,
1112                                                script_info);
1113     }
1114
1115   bool added = this->archive_->add_symbols(this->symtab_, this->layout_,
1116                                            this->input_objects_,
1117                                            this->mapfile_);
1118   this->archive_->unlock_nested_archives();
1119
1120   this->archive_->release();
1121   this->archive_->clear_uncached_views();
1122
1123   if (!added)
1124     {
1125       // This archive holds object files which are incompatible with
1126       // our output file.
1127       Read_symbols::incompatible_warning(this->input_argument_,
1128                                          this->archive_->input_file());
1129       Read_symbols::requeue(workqueue, this->input_objects_, this->symtab_,
1130                             this->layout_, this->dirpath_, this->dirindex_,
1131                             this->mapfile_, this->input_argument_,
1132                             this->input_group_, this->next_blocker_);
1133       delete this->archive_;
1134       return;
1135     }
1136
1137   if (this->input_group_ != NULL)
1138     this->input_group_->add_archive(this->archive_);
1139   else
1140     {
1141       // For an incremental link, finish recording the layout information.
1142       if (incremental_inputs != NULL)
1143         incremental_inputs->report_archive_end(this->archive_);
1144
1145       if (!parameters->options().has_plugins()
1146           || this->archive_->input_file()->options().whole_archive())
1147         {
1148           // We no longer need to know about this archive.
1149           delete this->archive_;
1150         }
1151       else
1152         {
1153           // The plugin interface may want to rescan this archive.
1154           parameters->options().plugins()->save_archive(this->archive_);
1155         }
1156
1157       this->archive_ = NULL;
1158     }
1159 }
1160
1161 // Class Lib_group static variables.
1162 unsigned int Lib_group::total_lib_groups;
1163 unsigned int Lib_group::total_members;
1164 unsigned int Lib_group::total_members_loaded;
1165
1166 Lib_group::Lib_group(const Input_file_lib* lib, Task* task)
1167   : Library_base(task), members_()
1168 {
1169   this->members_.resize(lib->size());
1170 }
1171
1172 const std::string&
1173 Lib_group::do_filename() const
1174 {
1175   std::string *filename = new std::string("/group/");
1176   return *filename;
1177 }
1178
1179 // Select members from the lib group and add them to the link.  We walk
1180 // through the members, and check if each one up should be included.
1181 // If the object says it should be included, we do so.  We have to do
1182 // this in a loop, since including one member may create new undefined
1183 // symbols which may be satisfied by other members.
1184
1185 void
1186 Lib_group::add_symbols(Symbol_table* symtab, Layout* layout,
1187                        Input_objects* input_objects)
1188 {
1189   ++Lib_group::total_lib_groups;
1190
1191   Lib_group::total_members += this->members_.size();
1192
1193   bool added_new_object;
1194   do
1195     {
1196       added_new_object = false;
1197       unsigned int i = 0;
1198       while (i < this->members_.size())
1199         {
1200           const Archive_member& member = this->members_[i];
1201           Object* obj = member.obj_;
1202           std::string why;
1203
1204           // Skip files with no symbols. Plugin objects have
1205           // member.sd_ == NULL.
1206           if (obj != NULL
1207               && (member.sd_ == NULL || member.sd_->symbol_names != NULL))
1208             {
1209               Archive::Should_include t = obj->should_include_member(symtab,
1210                                                                      layout,
1211                                                                      member.sd_,
1212                                                                      &why);
1213
1214               if (t != Archive::SHOULD_INCLUDE_YES)
1215                 {
1216                   ++i;
1217                   continue;
1218                 }
1219
1220               this->include_member(symtab, layout, input_objects, member);
1221
1222               added_new_object = true;
1223             }
1224           else
1225             {
1226               if (member.sd_ != NULL)
1227                 {
1228                   // The file must be locked in order to destroy the views
1229                   // associated with it.
1230                   gold_assert(obj != NULL);
1231                   obj->lock(this->task_);
1232                   delete member.sd_;
1233                   obj->unlock(this->task_);
1234                 }
1235             }
1236
1237           this->members_[i] = this->members_.back();
1238           this->members_.pop_back();
1239         }
1240     }
1241   while (added_new_object);
1242 }
1243
1244 // Include a lib group member in the link.
1245
1246 void
1247 Lib_group::include_member(Symbol_table* symtab, Layout* layout,
1248                           Input_objects* input_objects,
1249                           const Archive_member& member)
1250 {
1251   ++Lib_group::total_members_loaded;
1252
1253   Object* obj = member.obj_;
1254   gold_assert(obj != NULL);
1255
1256   Pluginobj* pluginobj = obj->pluginobj();
1257   if (pluginobj != NULL)
1258     {
1259       pluginobj->add_symbols(symtab, NULL, layout);
1260       return;
1261     }
1262
1263   Read_symbols_data* sd = member.sd_;
1264   gold_assert(sd != NULL);
1265   obj->lock(this->task_);
1266   if (input_objects->add_object(obj))
1267     {
1268       if (layout->incremental_inputs() != NULL)
1269         layout->incremental_inputs()->report_object(obj, member.arg_serial_,
1270                                                     this, NULL);
1271       obj->layout(symtab, layout, sd);
1272       obj->add_symbols(symtab, sd, layout);
1273     }
1274   delete sd;
1275   // Unlock the file for the next task.
1276   obj->unlock(this->task_);
1277 }
1278
1279 // Iterate over all unused symbols, and call the visitor class V for each.
1280
1281 void
1282 Lib_group::do_for_all_unused_symbols(Symbol_visitor_base* v) const
1283 {
1284   // Files are removed from the members list when used, so all the
1285   // files remaining on the list are unused.
1286   for (std::vector<Archive_member>::const_iterator p = this->members_.begin();
1287        p != this->members_.end();
1288        ++p)
1289     {
1290       Object* obj = p->obj_;
1291       obj->for_all_global_symbols(p->sd_, v);
1292     }
1293 }
1294
1295 // Print statistical information to stderr.  This is used for --stats.
1296
1297 void
1298 Lib_group::print_stats()
1299 {
1300   fprintf(stderr, _("%s: lib groups: %u\n"),
1301           program_name, Lib_group::total_lib_groups);
1302   fprintf(stderr, _("%s: total lib groups members: %u\n"),
1303           program_name, Lib_group::total_members);
1304   fprintf(stderr, _("%s: loaded lib groups members: %u\n"),
1305           program_name, Lib_group::total_members_loaded);
1306 }
1307
1308 Task_token*
1309 Add_lib_group_symbols::is_runnable()
1310 {
1311   if (this->readsyms_blocker_ != NULL && this->readsyms_blocker_->is_blocked())
1312     return this->readsyms_blocker_;
1313   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
1314     return this->this_blocker_;
1315   return NULL;
1316 }
1317
1318 void
1319 Add_lib_group_symbols::locks(Task_locker* tl)
1320 {
1321   tl->add(this, this->next_blocker_);
1322 }
1323
1324 void
1325 Add_lib_group_symbols::run(Workqueue*)
1326 {
1327   // For an incremental link, begin recording layout information.
1328   Incremental_inputs* incremental_inputs = this->layout_->incremental_inputs();
1329   if (incremental_inputs != NULL)
1330     incremental_inputs->report_archive_begin(this->lib_, 0, NULL);
1331
1332   this->lib_->add_symbols(this->symtab_, this->layout_, this->input_objects_);
1333
1334   if (incremental_inputs != NULL)
1335     incremental_inputs->report_archive_end(this->lib_);
1336 }
1337
1338 Add_lib_group_symbols::~Add_lib_group_symbols()
1339 {
1340   if (this->this_blocker_ != NULL)
1341     delete this->this_blocker_;
1342   // next_blocker_ is deleted by the task associated with the next
1343   // input file.
1344 }
1345
1346 } // End namespace gold.