ld/plugin.c

   1 /* Plugin control for the GNU linker.
   2    Copyright 2010, 2011 Free Software Foundation, Inc.
   3
   4    This file is part of the GNU Binutils.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #include "sysdep.h"
  22 #include "libiberty.h"
  23 #include "bfd.h"
  24 #include "bfdlink.h"
  25 #include "bfdver.h"
  26 #include "ld.h"
  27 #include "ldmain.h"
  28 #include "ldmisc.h"
  29 #include "ldexp.h"
  30 #include "ldlang.h"
  31 #include "ldfile.h"
  32 #include "plugin.h"
  33 #include "plugin-api.h"
  34 #include "elf-bfd.h"
  35 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
  36 #include <windows.h>
  37 #endif
  38
  39 /* Report plugin symbols.  */
  40 bfd_boolean report_plugin_symbols;
  41
  42 /* The suffix to append to the name of the real (claimed) object file
  43    when generating a dummy BFD to hold the IR symbols sent from the
  44    plugin.  For cosmetic use only; appears in maps, crefs etc.  */
  45 #define IRONLY_SUFFIX " (symbol from plugin)"
  46
  47 /* Stores a single argument passed to a plugin.  */
  48 typedef struct plugin_arg
  49 {
  50   struct plugin_arg *next;
  51   const char *arg;
  52 } plugin_arg_t;
  53
  54 /* Holds all details of a single plugin.  */
  55 typedef struct plugin
  56 {
  57   /* Next on the list of plugins, or NULL at end of chain.  */
  58   struct plugin *next;
  59   /* The argument string given to --plugin.  */
  60   const char *name;
  61   /* The shared library handle returned by dlopen.  */
  62   void *dlhandle;
  63   /* The list of argument string given to --plugin-opt.  */
  64   plugin_arg_t *args;
  65   /* Number of args in the list, for convenience.  */
  66   size_t n_args;
  67   /* The plugin's event handlers.  */
  68   ld_plugin_claim_file_handler claim_file_handler;
  69   ld_plugin_all_symbols_read_handler all_symbols_read_handler;
  70   ld_plugin_cleanup_handler cleanup_handler;
  71   /* TRUE if the cleanup handlers have been called.  */
  72   bfd_boolean cleanup_done;
  73 } plugin_t;
  74
  75 /* The master list of all plugins.  */
  76 static plugin_t *plugins_list = NULL;
  77
  78 /* We keep a tail pointer for easy linking on the end.  */
  79 static plugin_t **plugins_tail_chain_ptr = &plugins_list;
  80
  81 /* The last plugin added to the list, for receiving args.  */
  82 static plugin_t *last_plugin = NULL;
  83
  84 /* The tail of the arg chain of the last plugin added to the list.  */
  85 static plugin_arg_t **last_plugin_args_tail_chain_ptr = NULL;
  86
  87 /* The plugin which is currently having a callback executed.  */
  88 static plugin_t *called_plugin = NULL;
  89
  90 /* Last plugin to cause an error, if any.  */
  91 static const char *error_plugin = NULL;
  92
  93 /* State of linker "notice" interface before we poked at it.  */
  94 static bfd_boolean orig_notice_all;
  95
  96 /* Original linker callbacks, and the plugin version.  */
  97 static const struct bfd_link_callbacks *orig_callbacks;
  98 static struct bfd_link_callbacks plugin_callbacks;
  99
 100 /* Set at all symbols read time, to avoid recursively offering the plugin
 101    its own newly-added input files and libs to claim.  */
 102 bfd_boolean no_more_claiming = FALSE;
 103
 104 /* List of tags to set in the constant leading part of the tv array. */
 105 static const enum ld_plugin_tag tv_header_tags[] =
 106 {
 107   LDPT_MESSAGE,
 108   LDPT_API_VERSION,
 109   LDPT_GNU_LD_VERSION,
 110   LDPT_LINKER_OUTPUT,
 111   LDPT_OUTPUT_NAME,
 112   LDPT_REGISTER_CLAIM_FILE_HOOK,
 113   LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
 114   LDPT_REGISTER_CLEANUP_HOOK,
 115   LDPT_ADD_SYMBOLS,
 116   LDPT_GET_INPUT_FILE,
 117   LDPT_RELEASE_INPUT_FILE,
 118   LDPT_GET_SYMBOLS,
 119   LDPT_GET_SYMBOLS_V2,
 120   LDPT_ADD_INPUT_FILE,
 121   LDPT_ADD_INPUT_LIBRARY,
 122   LDPT_SET_EXTRA_LIBRARY_PATH
 123 };
 124
 125 /* How many entries in the constant leading part of the tv array.  */
 126 static const size_t tv_header_size = ARRAY_SIZE (tv_header_tags);
 127
 128 /* Forward references.  */
 129 static bfd_boolean plugin_notice (struct bfd_link_info *,
 130                                   struct bfd_link_hash_entry *, bfd *,
 131                                   asection *, bfd_vma, flagword, const char *);
 132
 133 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
 134
 135 #define RTLD_NOW 0      /* Dummy value.  */
 136
 137 static void *
 138 dlopen (const char *file, int mode ATTRIBUTE_UNUSED)
 139 {
 140   return LoadLibrary (file);
 141 }
 142
 143 static void *
 144 dlsym (void *handle, const char *name)
 145 {
 146   return GetProcAddress (handle, name);
 147 }
 148
 149 static int
 150 dlclose (void *handle)
 151 {
 152   FreeLibrary (handle);
 153   return 0;
 154 }
 155
 156 #endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)  */
 157
 158 /* Helper function for exiting with error status.  */
 159 static int
 160 set_plugin_error (const char *plugin)
 161 {
 162   error_plugin = plugin;
 163   return -1;
 164 }
 165
 166 /* Test if an error occurred.  */
 167 static bfd_boolean
 168 plugin_error_p (void)
 169 {
 170   return error_plugin != NULL;
 171 }
 172
 173 /* Return name of plugin which caused an error if any.  */
 174 const char *
 175 plugin_error_plugin (void)
 176 {
 177   return error_plugin ? error_plugin : _("<no plugin>");
 178 }
 179
 180 /* Handle -plugin arg: find and load plugin, or return error.  */
 181 int
 182 plugin_opt_plugin (const char *plugin)
 183 {
 184   plugin_t *newplug;
 185
 186   newplug = xmalloc (sizeof *newplug);
 187   memset (newplug, 0, sizeof *newplug);
 188   newplug->name = plugin;
 189   newplug->dlhandle = dlopen (plugin, RTLD_NOW);
 190   if (!newplug->dlhandle)
 191     return set_plugin_error (plugin);
 192
 193   /* Chain on end, so when we run list it is in command-line order.  */
 194   *plugins_tail_chain_ptr = newplug;
 195   plugins_tail_chain_ptr = &newplug->next;
 196
 197   /* Record it as current plugin for receiving args.  */
 198   last_plugin = newplug;
 199   last_plugin_args_tail_chain_ptr = &newplug->args;
 200   return 0;
 201 }
 202
 203 /* Accumulate option arguments for last-loaded plugin, or return
 204    error if none.  */
 205 int
 206 plugin_opt_plugin_arg (const char *arg)
 207 {
 208   plugin_arg_t *newarg;
 209
 210   if (!last_plugin)
 211     return set_plugin_error (_("<no plugin>"));
 212
 213   newarg = xmalloc (sizeof *newarg);
 214   newarg->arg = arg;
 215   newarg->next = NULL;
 216
 217   /* Chain on end to preserve command-line order.  */
 218   *last_plugin_args_tail_chain_ptr = newarg;
 219   last_plugin_args_tail_chain_ptr = &newarg->next;
 220   last_plugin->n_args++;
 221   return 0;
 222 }
 223
 224 /* Create a dummy BFD.  */
 225 bfd *
 226 plugin_get_ir_dummy_bfd (const char *name, bfd *srctemplate)
 227 {
 228   bfd *abfd;
 229
 230   bfd_use_reserved_id = 1;
 231   abfd = bfd_create (concat (name, IRONLY_SUFFIX, (const char *) NULL),
 232                      srctemplate);
 233   if (abfd != NULL)
 234     {
 235       abfd->flags |= BFD_LINKER_CREATED | BFD_PLUGIN;
 236       bfd_set_arch_info (abfd, bfd_get_arch_info (srctemplate));
 237       bfd_set_gp_size (abfd, bfd_get_gp_size (srctemplate));
 238       if (bfd_make_writable (abfd)
 239           && bfd_copy_private_bfd_data (srctemplate, abfd))
 240         {
 241           flagword flags;
 242
 243           /* Create section to own the symbols.  */
 244           flags = (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 245                    | SEC_ALLOC | SEC_LOAD | SEC_KEEP | SEC_EXCLUDE);
 246           if (bfd_make_section_anyway_with_flags (abfd, ".text", flags))
 247             return abfd;
 248         }
 249     }
 250   einfo (_("could not create dummy IR bfd: %F%E\n"));
 251   return NULL;
 252 }
 253
 254 /* Check if the BFD passed in is an IR dummy object file.  */
 255 static bfd_boolean
 256 is_ir_dummy_bfd (const bfd *abfd)
 257 {
 258   /* ABFD can sometimes legitimately be NULL, e.g. when called from one
 259      of the linker callbacks for a symbol in the *ABS* or *UND* sections.
 260      Likewise, the usrdata field may be NULL if ABFD was added by the
 261      backend without a corresponding input statement, as happens e.g.
 262      when processing DT_NEEDED dependencies.  */
 263   return (abfd
 264           && abfd->usrdata
 265           && ((lang_input_statement_type *)(abfd->usrdata))->claimed);
 266 }
 267
 268 /* Helpers to convert between BFD and GOLD symbol formats.  */
 269 static enum ld_plugin_status
 270 asymbol_from_plugin_symbol (bfd *abfd, asymbol *asym,
 271                             const struct ld_plugin_symbol *ldsym)
 272 {
 273   flagword flags = BSF_NO_FLAGS;
 274   struct bfd_section *section;
 275
 276   asym->the_bfd = abfd;
 277   asym->name = (ldsym->version
 278                 ? concat (ldsym->name, "@", ldsym->version, (const char *) NULL)
 279                 : ldsym->name);
 280   asym->value = 0;
 281   switch (ldsym->def)
 282     {
 283     case LDPK_WEAKDEF:
 284       flags = BSF_WEAK;
 285       /* FALLTHRU */
 286     case LDPK_DEF:
 287       flags |= BSF_GLOBAL;
 288       if (ldsym->comdat_key)
 289         {
 290           char *name = concat (".gnu.linkonce.t.", ldsym->comdat_key,
 291                                (const char *) NULL);
 292           section = bfd_get_section_by_name (abfd, name);
 293           if (section != NULL)
 294             free (name);
 295           else
 296             {
 297               flagword sflags;
 298
 299               sflags = (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 300                         | SEC_ALLOC | SEC_LOAD | SEC_KEEP | SEC_EXCLUDE
 301                         | SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD);
 302               section = bfd_make_section_anyway_with_flags (abfd, name, sflags);
 303               if (section == NULL)
 304                 return LDPS_ERR;
 305             }
 306         }
 307       else
 308         section = bfd_get_section_by_name (abfd, ".text");
 309       break;
 310
 311     case LDPK_WEAKUNDEF:
 312       flags = BSF_WEAK;
 313       /* FALLTHRU */
 314     case LDPK_UNDEF:
 315       section = bfd_und_section_ptr;
 316       break;
 317
 318     case LDPK_COMMON:
 319       flags = BSF_GLOBAL;
 320       section = bfd_com_section_ptr;
 321       asym->value = ldsym->size;
 322       /* For ELF targets, set alignment of common symbol to 1.  */
 323       if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 324         {
 325           ((elf_symbol_type *) asym)->internal_elf_sym.st_shndx = SHN_COMMON;
 326           ((elf_symbol_type *) asym)->internal_elf_sym.st_value = 1;
 327         }
 328       break;
 329
 330     default:
 331       return LDPS_ERR;
 332     }
 333   asym->flags = flags;
 334   asym->section = section;
 335
 336   /* Visibility only applies on ELF targets.  */
 337   if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 338     {
 339       elf_symbol_type *elfsym = elf_symbol_from (abfd, asym);
 340       unsigned char visibility;
 341
 342       if (!elfsym)
 343         einfo (_("%P%F: %s: non-ELF symbol in ELF BFD!\n"), asym->name);
 344       switch (ldsym->visibility)
 345         {
 346         default:
 347           einfo (_("%P%F: unknown ELF symbol visibility: %d!\n"),
 348                  ldsym->visibility);
 349         case LDPV_DEFAULT:
 350           visibility = STV_DEFAULT;
 351           break;
 352         case LDPV_PROTECTED:
 353           visibility = STV_PROTECTED;
 354           break;
 355         case LDPV_INTERNAL:
 356           visibility = STV_INTERNAL;
 357           break;
 358         case LDPV_HIDDEN:
 359           visibility = STV_HIDDEN;
 360           break;
 361         }
 362       elfsym->internal_elf_sym.st_other
 363         = (visibility | (elfsym->internal_elf_sym.st_other
 364                          & ~ELF_ST_VISIBILITY (-1)));
 365     }
 366
 367   return LDPS_OK;
 368 }
 369
 370 /* Register a claim-file handler.  */
 371 static enum ld_plugin_status
 372 register_claim_file (ld_plugin_claim_file_handler handler)
 373 {
 374   ASSERT (called_plugin);
 375   called_plugin->claim_file_handler = handler;
 376   return LDPS_OK;
 377 }
 378
 379 /* Register an all-symbols-read handler.  */
 380 static enum ld_plugin_status
 381 register_all_symbols_read (ld_plugin_all_symbols_read_handler handler)
 382 {
 383   ASSERT (called_plugin);
 384   called_plugin->all_symbols_read_handler = handler;
 385   return LDPS_OK;
 386 }
 387
 388 /* Register a cleanup handler.  */
 389 static enum ld_plugin_status
 390 register_cleanup (ld_plugin_cleanup_handler handler)
 391 {
 392   ASSERT (called_plugin);
 393   called_plugin->cleanup_handler = handler;
 394   return LDPS_OK;
 395 }
 396
 397 /* Add symbols from a plugin-claimed input file.  */
 398 static enum ld_plugin_status
 399 add_symbols (void *handle, int nsyms, const struct ld_plugin_symbol *syms)
 400 {
 401   asymbol **symptrs;
 402   bfd *abfd = handle;
 403   int n;
 404
 405   ASSERT (called_plugin);
 406   symptrs = xmalloc (nsyms * sizeof *symptrs);
 407   for (n = 0; n < nsyms; n++)
 408     {
 409       enum ld_plugin_status rv;
 410       asymbol *bfdsym;
 411
 412       bfdsym = bfd_make_empty_symbol (abfd);
 413       symptrs[n] = bfdsym;
 414       rv = asymbol_from_plugin_symbol (abfd, bfdsym, syms + n);
 415       if (rv != LDPS_OK)
 416         return rv;
 417     }
 418   bfd_set_symtab (abfd, symptrs, nsyms);
 419   return LDPS_OK;
 420 }
 421
 422 /* Get the input file information with an open (possibly re-opened)
 423    file descriptor.  */
 424 static enum ld_plugin_status
 425 get_input_file (const void *handle, struct ld_plugin_input_file *file)
 426 {
 427   ASSERT (called_plugin);
 428   handle = handle;
 429   file = file;
 430   return LDPS_ERR;
 431 }
 432
 433 /* Release the input file.  */
 434 static enum ld_plugin_status
 435 release_input_file (const void *handle)
 436 {
 437   ASSERT (called_plugin);
 438   handle = handle;
 439   return LDPS_ERR;
 440 }
 441
 442 /* Return TRUE if a defined symbol might be reachable from outside the
 443    universe of claimed objects.  */
 444 static inline bfd_boolean
 445 is_visible_from_outside (struct ld_plugin_symbol *lsym, asection *section,
 446                          struct bfd_link_hash_entry *blhe)
 447 {
 448   struct bfd_sym_chain *sym;
 449
 450   /* Section's owner may be NULL if it is the absolute
 451      section, fortunately is_ir_dummy_bfd handles that.  */
 452   if (!is_ir_dummy_bfd (section->owner))
 453     return TRUE;
 454   if (link_info.relocatable)
 455     return TRUE;
 456   if (link_info.export_dynamic || link_info.shared)
 457     {
 458       /* Check if symbol is hidden by version script.  */
 459       if (bfd_hide_sym_by_version (link_info.version_info,
 460                                    blhe->root.string))
 461         return FALSE;
 462       /* Only ELF symbols really have visibility.  */
 463       if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
 464         {
 465           struct elf_link_hash_entry *el = (struct elf_link_hash_entry *)blhe;
 466           int vis = ELF_ST_VISIBILITY (el->other);
 467           return vis == STV_DEFAULT || vis == STV_PROTECTED;
 468         }
 469       /* On non-ELF targets, we can safely make inferences by considering
 470          what visibility the plugin would have liked to apply when it first
 471          sent us the symbol.  During ELF symbol processing, visibility only
 472          ever becomes more restrictive, not less, when symbols are merged,
 473          so this is a conservative estimate; it may give false positives,
 474          declaring something visible from outside when it in fact would
 475          not have been, but this will only lead to missed optimisation
 476          opportunities during LTRANS at worst; it will not give false
 477          negatives, which can lead to the disastrous conclusion that the
 478          related symbol is IRONLY.  (See GCC PR46319 for an example.)  */
 479       return (lsym->visibility == LDPV_DEFAULT
 480               || lsym->visibility == LDPV_PROTECTED);
 481     }
 482
 483   for (sym = &entry_symbol; sym != NULL; sym = sym->next)
 484     if (sym->name
 485         && strcmp (sym->name, blhe->root.string) == 0)
 486       return TRUE;
 487
 488   return FALSE;
 489 }
 490
 491 /* Get the symbol resolution info for a plugin-claimed input file.  */
 492 static enum ld_plugin_status
 493 get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms,
 494              int def_ironly_exp)
 495 {
 496   const bfd *abfd = handle;
 497   int n;
 498
 499   ASSERT (called_plugin);
 500   for (n = 0; n < nsyms; n++)
 501     {
 502       struct bfd_link_hash_entry *blhe;
 503       asection *owner_sec;
 504       int res;
 505
 506       if (syms[n].def != LDPK_UNDEF)
 507         blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
 508                                      FALSE, FALSE, TRUE);
 509       else
 510         blhe = bfd_wrapped_link_hash_lookup (link_info.output_bfd, &link_info,
 511                                              syms[n].name, FALSE, FALSE, TRUE);
 512       if (!blhe)
 513         {
 514           res = LDPR_UNKNOWN;
 515           goto report_symbol;
 516         }
 517
 518       /* Determine resolution from blhe type and symbol's original type.  */
 519       if (blhe->type == bfd_link_hash_undefined
 520           || blhe->type == bfd_link_hash_undefweak)
 521         {
 522           res = LDPR_UNDEF;
 523           goto report_symbol;
 524         }
 525       if (blhe->type != bfd_link_hash_defined
 526           && blhe->type != bfd_link_hash_defweak
 527           && blhe->type != bfd_link_hash_common)
 528         {
 529           /* We should not have a new, indirect or warning symbol here.  */
 530           einfo ("%P%F: %s: plugin symbol table corrupt (sym type %d)\n",
 531                  called_plugin->name, blhe->type);
 532         }
 533
 534       /* Find out which section owns the symbol.  Since it's not undef,
 535          it must have an owner; if it's not a common symbol, both defs
 536          and weakdefs keep it in the same place. */
 537       owner_sec = (blhe->type == bfd_link_hash_common
 538                    ? blhe->u.c.p->section
 539                    : blhe->u.def.section);
 540
 541
 542       /* If it was originally undefined or common, then it has been
 543          resolved; determine how.  */
 544       if (syms[n].def == LDPK_UNDEF
 545           || syms[n].def == LDPK_WEAKUNDEF
 546           || syms[n].def == LDPK_COMMON)
 547         {
 548           if (owner_sec->owner == link_info.output_bfd)
 549             res = LDPR_RESOLVED_EXEC;
 550           else if (owner_sec->owner == abfd)
 551             res = LDPR_PREVAILING_DEF_IRONLY;
 552           else if (is_ir_dummy_bfd (owner_sec->owner))
 553             res = LDPR_RESOLVED_IR;
 554           else if (owner_sec->owner != NULL
 555                    && (owner_sec->owner->flags & DYNAMIC) != 0)
 556             res = LDPR_RESOLVED_DYN;
 557           else
 558             res = LDPR_RESOLVED_EXEC;
 559         }
 560
 561       /* Was originally def, or weakdef.  Does it prevail?  If the
 562          owner is the original dummy bfd that supplied it, then this
 563          is the definition that has prevailed.  */
 564       else if (owner_sec->owner == link_info.output_bfd)
 565         res = LDPR_PREEMPTED_REG;
 566       else if (owner_sec->owner == abfd)
 567         res = LDPR_PREVAILING_DEF_IRONLY;
 568
 569       /* Was originally def, weakdef, or common, but has been pre-empted.  */
 570       else if (is_ir_dummy_bfd (owner_sec->owner))
 571         res = LDPR_PREEMPTED_IR;
 572       else
 573         res = LDPR_PREEMPTED_REG;
 574
 575       if (res == LDPR_PREVAILING_DEF_IRONLY)
 576         {
 577           /* We need to know if the sym is referenced from non-IR files.  Or
 578              even potentially-referenced, perhaps in a future final link if
 579              this is a partial one, perhaps dynamically at load-time if the
 580              symbol is externally visible.  */
 581           if (blhe->non_ir_ref)
 582             res = LDPR_PREVAILING_DEF;
 583           else if (is_visible_from_outside (&syms[n], owner_sec, blhe))
 584             res = def_ironly_exp;
 585         }
 586
 587     report_symbol:
 588       syms[n].resolution = res;
 589       if (report_plugin_symbols)
 590         einfo (_("%P: %B: symbol `%s' "
 591                  "definition: %d, visibility: %d, resolution: %d\n"),
 592                abfd, syms[n].name,
 593                syms[n].def, syms[n].visibility, res);
 594     }
 595   return LDPS_OK;
 596 }
 597
 598 static enum ld_plugin_status
 599 get_symbols_v1 (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 600 {
 601   return get_symbols (handle, nsyms, syms, LDPR_PREVAILING_DEF);
 602 }
 603
 604 static enum ld_plugin_status
 605 get_symbols_v2 (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 606 {
 607   return get_symbols (handle, nsyms, syms, LDPR_PREVAILING_DEF_IRONLY_EXP);
 608 }
 609
 610 /* Add a new (real) input file generated by a plugin.  */
 611 static enum ld_plugin_status
 612 add_input_file (const char *pathname)
 613 {
 614   ASSERT (called_plugin);
 615   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
 616                             NULL))
 617     return LDPS_ERR;
 618   return LDPS_OK;
 619 }
 620
 621 /* Add a new (real) library required by a plugin.  */
 622 static enum ld_plugin_status
 623 add_input_library (const char *pathname)
 624 {
 625   ASSERT (called_plugin);
 626   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
 627                             NULL))
 628     return LDPS_ERR;
 629   return LDPS_OK;
 630 }
 631
 632 /* Set the extra library path to be used by libraries added via
 633    add_input_library.  */
 634 static enum ld_plugin_status
 635 set_extra_library_path (const char *path)
 636 {
 637   ASSERT (called_plugin);
 638   ldfile_add_library_path (xstrdup (path), FALSE);
 639   return LDPS_OK;
 640 }
 641
 642 /* Issue a diagnostic message from a plugin.  */
 643 static enum ld_plugin_status
 644 message (int level, const char *format, ...)
 645 {
 646   va_list args;
 647   va_start (args, format);
 648
 649   switch (level)
 650     {
 651     case LDPL_INFO:
 652       vfinfo (stdout, format, args, FALSE);
 653       putchar ('\n');
 654       break;
 655     case LDPL_WARNING:
 656       vfinfo (stdout, format, args, TRUE);
 657       putchar ('\n');
 658       break;
 659     case LDPL_FATAL:
 660     case LDPL_ERROR:
 661     default:
 662       {
 663         char *newfmt = ACONCAT ((level == LDPL_FATAL ? "%P%F: " : "%P%X: ",
 664                                  format, "\n", (const char *) NULL));
 665         fflush (stdout);
 666         vfinfo (stderr, newfmt, args, TRUE);
 667         fflush (stderr);
 668       }
 669       break;
 670     }
 671
 672   va_end (args);
 673   return LDPS_OK;
 674 }
 675
 676 /* Helper to size leading part of tv array and set it up. */
 677 static void
 678 set_tv_header (struct ld_plugin_tv *tv)
 679 {
 680   size_t i;
 681
 682   /* Version info.  */
 683   static const unsigned int major = (unsigned)(BFD_VERSION / 100000000UL);
 684   static const unsigned int minor = (unsigned)(BFD_VERSION / 1000000UL) % 100;
 685
 686   for (i = 0; i < tv_header_size; i++)
 687     {
 688       tv[i].tv_tag = tv_header_tags[i];
 689 #define TVU(x) tv[i].tv_u.tv_ ## x
 690       switch (tv[i].tv_tag)
 691         {
 692         case LDPT_MESSAGE:
 693           TVU(message) = message;
 694           break;
 695         case LDPT_API_VERSION:
 696           TVU(val) = LD_PLUGIN_API_VERSION;
 697           break;
 698         case LDPT_GNU_LD_VERSION:
 699           TVU(val) = major * 100 + minor;
 700           break;
 701         case LDPT_LINKER_OUTPUT:
 702           TVU(val) = (link_info.relocatable
 703                       ? LDPO_REL
 704                       : (link_info.shared ? LDPO_DYN : LDPO_EXEC));
 705           break;
 706         case LDPT_OUTPUT_NAME:
 707           TVU(string) = output_filename;
 708           break;
 709         case LDPT_REGISTER_CLAIM_FILE_HOOK:
 710           TVU(register_claim_file) = register_claim_file;
 711           break;
 712         case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
 713           TVU(register_all_symbols_read) = register_all_symbols_read;
 714           break;
 715         case LDPT_REGISTER_CLEANUP_HOOK:
 716           TVU(register_cleanup) = register_cleanup;
 717           break;
 718         case LDPT_ADD_SYMBOLS:
 719           TVU(add_symbols) = add_symbols;
 720           break;
 721         case LDPT_GET_INPUT_FILE:
 722           TVU(get_input_file) = get_input_file;
 723           break;
 724         case LDPT_RELEASE_INPUT_FILE:
 725           TVU(release_input_file) = release_input_file;
 726           break;
 727         case LDPT_GET_SYMBOLS:
 728           TVU(get_symbols) = get_symbols_v1;
 729           break;
 730         case LDPT_GET_SYMBOLS_V2:
 731           TVU(get_symbols) = get_symbols_v2;
 732           break;
 733         case LDPT_ADD_INPUT_FILE:
 734           TVU(add_input_file) = add_input_file;
 735           break;
 736         case LDPT_ADD_INPUT_LIBRARY:
 737           TVU(add_input_library) = add_input_library;
 738           break;
 739         case LDPT_SET_EXTRA_LIBRARY_PATH:
 740           TVU(set_extra_library_path) = set_extra_library_path;
 741           break;
 742         default:
 743           /* Added a new entry to the array without adding
 744              a new case to set up its value is a bug.  */
 745           FAIL ();
 746         }
 747 #undef TVU
 748     }
 749 }
 750
 751 /* Append the per-plugin args list and trailing LDPT_NULL to tv.  */
 752 static void
 753 set_tv_plugin_args (plugin_t *plugin, struct ld_plugin_tv *tv)
 754 {
 755   plugin_arg_t *arg = plugin->args;
 756   while (arg)
 757     {
 758       tv->tv_tag = LDPT_OPTION;
 759       tv->tv_u.tv_string = arg->arg;
 760       arg = arg->next;
 761       tv++;
 762     }
 763   tv->tv_tag = LDPT_NULL;
 764   tv->tv_u.tv_val = 0;
 765 }
 766
 767 /* Return true if any plugins are active this run.  Only valid
 768    after options have been processed.  */
 769 bfd_boolean
 770 plugin_active_plugins_p (void)
 771 {
 772   return plugins_list != NULL;
 773 }
 774
 775 /* Load up and initialise all plugins after argument parsing.  */
 776 int
 777 plugin_load_plugins (void)
 778 {
 779   struct ld_plugin_tv *my_tv;
 780   unsigned int max_args = 0;
 781   plugin_t *curplug = plugins_list;
 782
 783   /* If there are no plugins, we need do nothing this run.  */
 784   if (!curplug)
 785     return 0;
 786
 787   /* First pass over plugins to find max # args needed so that we
 788      can size and allocate the tv array.  */
 789   while (curplug)
 790     {
 791       if (curplug->n_args > max_args)
 792         max_args = curplug->n_args;
 793       curplug = curplug->next;
 794     }
 795
 796   /* Allocate tv array and initialise constant part.  */
 797   my_tv = xmalloc ((max_args + 1 + tv_header_size) * sizeof *my_tv);
 798   set_tv_header (my_tv);
 799
 800   /* Pass over plugins again, activating them.  */
 801   curplug = plugins_list;
 802   while (curplug)
 803     {
 804       enum ld_plugin_status rv;
 805       ld_plugin_onload onloadfn = dlsym (curplug->dlhandle, "onload");
 806       if (!onloadfn)
 807         onloadfn = dlsym (curplug->dlhandle, "_onload");
 808       if (!onloadfn)
 809         return set_plugin_error (curplug->name);
 810       set_tv_plugin_args (curplug, &my_tv[tv_header_size]);
 811       called_plugin = curplug;
 812       rv = (*onloadfn) (my_tv);
 813       called_plugin = NULL;
 814       if (rv != LDPS_OK)
 815         return set_plugin_error (curplug->name);
 816       curplug = curplug->next;
 817     }
 818
 819   /* Since plugin(s) inited ok, assume they're going to want symbol
 820      resolutions, which needs us to track which symbols are referenced
 821      by non-IR files using the linker's notice callback.  */
 822   orig_notice_all = link_info.notice_all;
 823   orig_callbacks = link_info.callbacks;
 824   plugin_callbacks = *orig_callbacks;
 825   plugin_callbacks.notice = &plugin_notice;
 826   link_info.notice_all = TRUE;
 827   link_info.callbacks = &plugin_callbacks;
 828
 829   return 0;
 830 }
 831
 832 /* Call 'claim file' hook for all plugins.  */
 833 static int
 834 plugin_call_claim_file (const struct ld_plugin_input_file *file, int *claimed)
 835 {
 836   plugin_t *curplug = plugins_list;
 837   *claimed = FALSE;
 838   if (no_more_claiming)
 839     return 0;
 840   while (curplug && !*claimed)
 841     {
 842       if (curplug->claim_file_handler)
 843         {
 844           enum ld_plugin_status rv;
 845           called_plugin = curplug;
 846           rv = (*curplug->claim_file_handler) (file, claimed);
 847           called_plugin = NULL;
 848           if (rv != LDPS_OK)
 849             set_plugin_error (curplug->name);
 850         }
 851       curplug = curplug->next;
 852     }
 853   return plugin_error_p () ? -1 : 0;
 854 }
 855
 856 void
 857 plugin_maybe_claim (struct ld_plugin_input_file *file,
 858                     lang_input_statement_type *entry)
 859 {
 860   int claimed = 0;
 861
 862   /* We create a dummy BFD, initially empty, to house whatever symbols
 863      the plugin may want to add.  */
 864   file->handle = plugin_get_ir_dummy_bfd (entry->the_bfd->filename,
 865                                           entry->the_bfd);
 866   if (plugin_call_claim_file (file, &claimed))
 867     einfo (_("%P%F: %s: plugin reported error claiming file\n"),
 868            plugin_error_plugin ());
 869   /* fd belongs to us, not the plugin; but we don't need it.  */
 870   close (file->fd);
 871   if (claimed)
 872     {
 873       /* Discard the real file's BFD and substitute the dummy one.  */
 874
 875       /* BFD archive handling caches elements so we can't call
 876          bfd_close for archives.  */
 877       if (entry->the_bfd->my_archive == NULL)
 878         bfd_close (entry->the_bfd);
 879       entry->the_bfd = file->handle;
 880       entry->claimed = TRUE;
 881       bfd_make_readable (entry->the_bfd);
 882     }
 883   else
 884     {
 885       /* If plugin didn't claim the file, we don't need the dummy bfd.
 886          Can't avoid speculatively creating it, alas.  */
 887       bfd_close_all_done (file->handle);
 888       entry->claimed = FALSE;
 889     }
 890 }
 891
 892 /* Call 'all symbols read' hook for all plugins.  */
 893 int
 894 plugin_call_all_symbols_read (void)
 895 {
 896   plugin_t *curplug = plugins_list;
 897
 898   /* Disable any further file-claiming.  */
 899   no_more_claiming = TRUE;
 900
 901   while (curplug)
 902     {
 903       if (curplug->all_symbols_read_handler)
 904         {
 905           enum ld_plugin_status rv;
 906           called_plugin = curplug;
 907           rv = (*curplug->all_symbols_read_handler) ();
 908           called_plugin = NULL;
 909           if (rv != LDPS_OK)
 910             set_plugin_error (curplug->name);
 911         }
 912       curplug = curplug->next;
 913     }
 914   return plugin_error_p () ? -1 : 0;
 915 }
 916
 917 /* Call 'cleanup' hook for all plugins at exit.  */
 918 void
 919 plugin_call_cleanup (void)
 920 {
 921   plugin_t *curplug = plugins_list;
 922   while (curplug)
 923     {
 924       if (curplug->cleanup_handler && !curplug->cleanup_done)
 925         {
 926           enum ld_plugin_status rv;
 927           curplug->cleanup_done = TRUE;
 928           called_plugin = curplug;
 929           rv = (*curplug->cleanup_handler) ();
 930           called_plugin = NULL;
 931           if (rv != LDPS_OK)
 932             set_plugin_error (curplug->name);
 933           dlclose (curplug->dlhandle);
 934         }
 935       curplug = curplug->next;
 936     }
 937   if (plugin_error_p ())
 938     info_msg (_("%P: %s: error in plugin cleanup (ignored)\n"),
 939               plugin_error_plugin ());
 940 }
 941
 942 /* To determine which symbols should be resolved LDPR_PREVAILING_DEF
 943    and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
 944    the linker adds them to the linker hash table.  Mark those
 945    referenced from a non-IR file with non_ir_ref.  We have to
 946    notice_all symbols, because we won't necessarily know until later
 947    which ones will be contributed by IR files.  */
 948 static bfd_boolean
 949 plugin_notice (struct bfd_link_info *info,
 950                struct bfd_link_hash_entry *h,
 951                bfd *abfd,
 952                asection *section,
 953                bfd_vma value,
 954                flagword flags,
 955                const char *string)
 956 {
 957   if (h != NULL)
 958     {
 959       bfd *sym_bfd;
 960
 961       /* No further processing if this def/ref is from an IR dummy BFD.  */
 962       if (is_ir_dummy_bfd (abfd))
 963         return TRUE;
 964
 965       /* Making an indirect symbol counts as a reference unless this
 966          is a brand new symbol.  */
 967       if (bfd_is_ind_section (section)
 968           || (flags & BSF_INDIRECT) != 0)
 969         {
 970           if (h->type != bfd_link_hash_new)
 971             {
 972               struct bfd_link_hash_entry *inh;
 973
 974               h->non_ir_ref = TRUE;
 975               inh = bfd_wrapped_link_hash_lookup (abfd, info, string, FALSE,
 976                                                   FALSE, FALSE);
 977               if (inh != NULL)
 978                 inh->non_ir_ref = TRUE;
 979             }
 980         }
 981
 982       /* Nothing to do here for warning symbols.  */
 983       else if ((flags & BSF_WARNING) != 0)
 984         ;
 985
 986       /* Nothing to do here for constructor symbols.  */
 987       else if ((flags & BSF_CONSTRUCTOR) != 0)
 988         ;
 989
 990       /* If this is a ref, set non_ir_ref.  */
 991       else if (bfd_is_und_section (section))
 992         h->non_ir_ref = TRUE;
 993
 994       /* Otherwise, it must be a new def.  Ensure any symbol defined
 995          in an IR dummy BFD takes on a new value from a real BFD.
 996          Weak symbols are not normally overridden by a new weak
 997          definition, and strong symbols will normally cause multiple
 998          definition errors.  Avoid this by making the symbol appear
 999          to be undefined.  */
1000       else if (((h->type == bfd_link_hash_defweak
1001                  || h->type == bfd_link_hash_defined)
1002                 && is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
1003                || (h->type == bfd_link_hash_common
1004                    && is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
1005         {
1006           h->type = bfd_link_hash_undefweak;
1007           h->u.undef.abfd = sym_bfd;
1008         }
1009     }
1010
1011   /* Continue with cref/nocrossref/trace-sym processing.  */
1012   if (h == NULL
1013       || orig_notice_all
1014       || (info->notice_hash != NULL
1015           && bfd_hash_lookup (info->notice_hash, h->root.string,
1016                               FALSE, FALSE) != NULL))
1017     return (*orig_callbacks->notice) (info, h,
1018                                       abfd, section, value, flags, string);
1019   return TRUE;
1020 }