ld/plugin.c

   1 /* Plugin control for the GNU linker.
   2    Copyright 2010 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 /* The suffix to append to the name of the real (claimed) object file
  40    when generating a dummy BFD to hold the IR symbols sent from the
  41    plugin.  */
  42 #define IRONLY_SUFFIX           ".ironly\004"
  43
  44 /* This is sizeof an array of chars, not sizeof a const char *.  We
  45    also have to avoid inadvertently counting the trailing NUL.  */
  46 #define IRONLY_SUFFIX_LEN       (sizeof (IRONLY_SUFFIX) - 1)
  47
  48 /* Stores a single argument passed to a plugin.  */
  49 typedef struct plugin_arg
  50 {
  51   struct plugin_arg *next;
  52   const char *arg;
  53 } plugin_arg_t;
  54
  55 /* Holds all details of a single plugin.  */
  56 typedef struct plugin
  57 {
  58   /* Next on the list of plugins, or NULL at end of chain.  */
  59   struct plugin *next;
  60   /* The argument string given to --plugin.  */
  61   const char *name;
  62   /* The shared library handle returned by dlopen.  */
  63   void *dlhandle;
  64   /* The list of argument string given to --plugin-opt.  */
  65   plugin_arg_t *args;
  66   /* Number of args in the list, for convenience.  */
  67   size_t n_args;
  68   /* The plugin's event handlers.  */
  69   ld_plugin_claim_file_handler claim_file_handler;
  70   ld_plugin_all_symbols_read_handler all_symbols_read_handler;
  71   ld_plugin_cleanup_handler cleanup_handler;
  72   /* TRUE if the cleanup handlers have been called.  */
  73   bfd_boolean cleanup_done;
  74 } plugin_t;
  75
  76 /* The master list of all plugins.  */
  77 static plugin_t *plugins_list = NULL;
  78
  79 /* We keep a tail pointer for easy linking on the end.  */
  80 static plugin_t **plugins_tail_chain_ptr = &plugins_list;
  81
  82 /* The last plugin added to the list, for receiving args.  */
  83 static plugin_t *last_plugin = NULL;
  84
  85 /* The tail of the arg chain of the last plugin added to the list.  */
  86 static plugin_arg_t **last_plugin_args_tail_chain_ptr = NULL;
  87
  88 /* The plugin which is currently having a callback executed.  */
  89 static plugin_t *called_plugin = NULL;
  90
  91 /* Last plugin to cause an error, if any.  */
  92 static const char *error_plugin = NULL;
  93
  94 /* A hash table that records symbols referenced by non-IR files.  Used
  95    at get_symbols time to determine whether any prevailing defs from
  96    IR files are referenced only from other IR files, so tthat we can
  97    we can distinguish the LDPR_PREVAILING_DEF and LDPR_PREVAILING_DEF_IRONLY
  98    cases when establishing symbol resolutions.  */
  99 static struct bfd_hash_table *non_ironly_hash = NULL;
 100
 101 /* Set at all symbols read time, to avoid recursively offering the plugin
 102    its own newly-added input files and libs to claim.  */
 103 static bfd_boolean no_more_claiming = FALSE;
 104
 105 /* If the --allow-multiple-definition command-line option is active, we
 106    have to disable it so that BFD always calls our hook, and simulate the
 107    effect (when not resolving IR vs. real symbols) ourselves by ensuring
 108    TRUE is returned from the hook.  */
 109 static bfd_boolean plugin_cached_allow_multiple_defs = FALSE;
 110
 111 /* Call 'cleanup' hook for all plugins at exit.  */
 112 static void plugin_call_cleanup (void);
 113
 114 /* List of tags to set in the constant leading part of the tv array. */
 115 static const enum ld_plugin_tag tv_header_tags[] =
 116 {
 117   LDPT_MESSAGE,
 118   LDPT_API_VERSION,
 119   LDPT_GNU_LD_VERSION,
 120   LDPT_LINKER_OUTPUT,
 121   LDPT_OUTPUT_NAME,
 122   LDPT_REGISTER_CLAIM_FILE_HOOK,
 123   LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
 124   LDPT_REGISTER_CLEANUP_HOOK,
 125   LDPT_ADD_SYMBOLS,
 126   LDPT_GET_INPUT_FILE,
 127   LDPT_RELEASE_INPUT_FILE,
 128   LDPT_GET_SYMBOLS,
 129   LDPT_ADD_INPUT_FILE,
 130   LDPT_ADD_INPUT_LIBRARY,
 131   LDPT_SET_EXTRA_LIBRARY_PATH
 132 };
 133
 134 /* How many entries in the constant leading part of the tv array.  */
 135 static const size_t tv_header_size = ARRAY_SIZE (tv_header_tags);
 136
 137 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
 138
 139 #define RTLD_NOW 0      /* Dummy value.  */
 140
 141 static void *
 142 dlopen (const char *file, int mode ATTRIBUTE_UNUSED)
 143 {
 144   return LoadLibrary (file);
 145 }
 146
 147 static void *
 148 dlsym (void *handle, const char *name)
 149 {
 150   return GetProcAddress (handle, name);
 151 }
 152
 153 static int
 154 dlclose (void *handle)
 155 {
 156   FreeLibrary (handle);
 157   return 0;
 158 }
 159
 160 #endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)  */
 161
 162 /* Helper function for exiting with error status.  */
 163 static int
 164 set_plugin_error (const char *plugin)
 165 {
 166   error_plugin = plugin;
 167   return -1;
 168 }
 169
 170 /* Test if an error occurred.  */
 171 static bfd_boolean
 172 plugin_error_p (void)
 173 {
 174   return error_plugin != NULL;
 175 }
 176
 177 /* Return name of plugin which caused an error if any.  */
 178 const char *
 179 plugin_error_plugin (void)
 180 {
 181   return error_plugin ? error_plugin : _("<no plugin>");
 182 }
 183
 184 /* Handle -plugin arg: find and load plugin, or return error.  */
 185 int
 186 plugin_opt_plugin (const char *plugin)
 187 {
 188   plugin_t *newplug;
 189
 190   newplug = xmalloc (sizeof *newplug);
 191   memset (newplug, 0, sizeof *newplug);
 192   newplug->name = plugin;
 193   newplug->dlhandle = dlopen (plugin, RTLD_NOW);
 194   if (!newplug->dlhandle)
 195     return set_plugin_error (plugin);
 196
 197   /* Chain on end, so when we run list it is in command-line order.  */
 198   *plugins_tail_chain_ptr = newplug;
 199   plugins_tail_chain_ptr = &newplug->next;
 200
 201   /* Record it as current plugin for receiving args.  */
 202   last_plugin = newplug;
 203   last_plugin_args_tail_chain_ptr = &newplug->args;
 204   return 0;
 205 }
 206
 207 /* Accumulate option arguments for last-loaded plugin, or return
 208    error if none.  */
 209 int
 210 plugin_opt_plugin_arg (const char *arg)
 211 {
 212   plugin_arg_t *newarg;
 213
 214   if (!last_plugin)
 215     return set_plugin_error (_("<no plugin>"));
 216
 217   newarg = xmalloc (sizeof *newarg);
 218   newarg->arg = arg;
 219   newarg->next = NULL;
 220
 221   /* Chain on end to preserve command-line order.  */
 222   *last_plugin_args_tail_chain_ptr = newarg;
 223   last_plugin_args_tail_chain_ptr = &newarg->next;
 224   last_plugin->n_args++;
 225   return 0;
 226 }
 227
 228 /* Create a dummy BFD.  */
 229 bfd *
 230 plugin_get_ir_dummy_bfd (const char *name, bfd *srctemplate)
 231 {
 232   asection *sec;
 233   bfd *abfd;
 234
 235   bfd_use_reserved_id = 1;
 236   abfd = bfd_create (concat (name, IRONLY_SUFFIX, (const char *)NULL),
 237                      srctemplate);
 238   bfd_set_arch_info (abfd, bfd_get_arch_info (srctemplate));
 239   bfd_make_writable (abfd);
 240   /* Create a minimal set of sections to own the symbols.  */
 241   sec = bfd_make_section_old_way (abfd, ".text");
 242   bfd_set_section_flags (abfd, sec,
 243                          (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 244                           | SEC_ALLOC | SEC_LOAD | SEC_KEEP));
 245   sec->output_section = sec;
 246   sec->output_offset = 0;
 247   return abfd;
 248 }
 249
 250 /* Check if the BFD passed in is an IR dummy object file.  */
 251 static bfd_boolean
 252 is_ir_dummy_bfd (const bfd *abfd)
 253 {
 254   size_t namlen;
 255
 256   if (abfd == NULL)
 257     return FALSE;
 258   namlen = strlen (abfd->filename);
 259   if (namlen < IRONLY_SUFFIX_LEN)
 260     return FALSE;
 261   return !strcmp (abfd->filename + namlen - IRONLY_SUFFIX_LEN, IRONLY_SUFFIX);
 262 }
 263
 264 /* Helpers to convert between BFD and GOLD symbol formats.  */
 265 static enum ld_plugin_status
 266 asymbol_from_plugin_symbol (bfd *abfd, asymbol *asym,
 267                             const struct ld_plugin_symbol *ldsym)
 268 {
 269   flagword flags = BSF_NO_FLAGS;
 270   struct bfd_section *section;
 271
 272   asym->the_bfd = abfd;
 273   asym->name = (ldsym->version
 274                 ? concat (ldsym->name, "@", ldsym->version, NULL)
 275                 : ldsym->name);
 276   asym->value = 0;
 277   switch (ldsym->def)
 278     {
 279     case LDPK_WEAKDEF:
 280       flags = BSF_WEAK;
 281       /* FALLTHRU */
 282     case LDPK_DEF:
 283       flags |= BSF_GLOBAL;
 284       section = bfd_get_section_by_name (abfd, ".text");
 285       break;
 286
 287     case LDPK_WEAKUNDEF:
 288       flags = BSF_WEAK;
 289       /* FALLTHRU */
 290     case LDPK_UNDEF:
 291       section = bfd_und_section_ptr;
 292       break;
 293
 294     case LDPK_COMMON:
 295       flags = BSF_GLOBAL;
 296       section = bfd_com_section_ptr;
 297       asym->value = ldsym->size;
 298       /* For ELF targets, set alignment of common symbol to 1.  */
 299       if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 300         ((elf_symbol_type *) asym)->internal_elf_sym.st_value = 1;
 301       break;
 302
 303     default:
 304       return LDPS_ERR;
 305     }
 306   asym->flags = flags;
 307   asym->section = section;
 308
 309   /* Visibility only applies on ELF targets.  */
 310   if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 311     {
 312       elf_symbol_type *elfsym = elf_symbol_from (abfd, asym);
 313       unsigned char visibility;
 314
 315       if (!elfsym)
 316         einfo (_("%P%F: %s: non-ELF symbol in ELF BFD!\n"), asym->name);
 317       switch (ldsym->visibility)
 318         {
 319         default:
 320           einfo (_("%P%F: unknown ELF symbol visibility: %d!\n"),
 321                  ldsym->visibility);
 322         case LDPV_DEFAULT:
 323           visibility = STV_DEFAULT;
 324           break;
 325         case LDPV_PROTECTED:
 326           visibility = STV_PROTECTED;
 327           break;
 328         case LDPV_INTERNAL:
 329           visibility = STV_INTERNAL;
 330           break;
 331         case LDPV_HIDDEN:
 332           visibility = STV_HIDDEN;
 333           break;
 334         }
 335       elfsym->internal_elf_sym.st_other
 336         = (visibility | (elfsym->internal_elf_sym.st_other
 337                          & ~ELF_ST_VISIBILITY (-1)));
 338     }
 339
 340   return LDPS_OK;
 341 }
 342
 343 /* Register a claim-file handler.  */
 344 static enum ld_plugin_status
 345 register_claim_file (ld_plugin_claim_file_handler handler)
 346 {
 347   ASSERT (called_plugin);
 348   called_plugin->claim_file_handler = handler;
 349   return LDPS_OK;
 350 }
 351
 352 /* Register an all-symbols-read handler.  */
 353 static enum ld_plugin_status
 354 register_all_symbols_read (ld_plugin_all_symbols_read_handler handler)
 355 {
 356   ASSERT (called_plugin);
 357   called_plugin->all_symbols_read_handler = handler;
 358   return LDPS_OK;
 359 }
 360
 361 /* Register a cleanup handler.  */
 362 static enum ld_plugin_status
 363 register_cleanup (ld_plugin_cleanup_handler handler)
 364 {
 365   ASSERT (called_plugin);
 366   called_plugin->cleanup_handler = handler;
 367   return LDPS_OK;
 368 }
 369
 370 /* Add symbols from a plugin-claimed input file.  */
 371 static enum ld_plugin_status
 372 add_symbols (void *handle, int nsyms, const struct ld_plugin_symbol *syms)
 373 {
 374   asymbol **symptrs;
 375   bfd *abfd = handle;
 376   int n;
 377   ASSERT (called_plugin);
 378   symptrs = xmalloc (nsyms * sizeof *symptrs);
 379   for (n = 0; n < nsyms; n++)
 380     {
 381       enum ld_plugin_status rv;
 382       asymbol *bfdsym = bfd_make_empty_symbol (abfd);
 383       symptrs[n] = bfdsym;
 384       rv = asymbol_from_plugin_symbol (abfd, bfdsym, syms + n);
 385       if (rv != LDPS_OK)
 386         return rv;
 387     }
 388   bfd_set_symtab (abfd, symptrs, nsyms);
 389   return LDPS_OK;
 390 }
 391
 392 /* Get the input file information with an open (possibly re-opened)
 393    file descriptor.  */
 394 static enum ld_plugin_status
 395 get_input_file (const void *handle, struct ld_plugin_input_file *file)
 396 {
 397   ASSERT (called_plugin);
 398   handle = handle;
 399   file = file;
 400   return LDPS_ERR;
 401 }
 402
 403 /* Release the input file.  */
 404 static enum ld_plugin_status
 405 release_input_file (const void *handle)
 406 {
 407   ASSERT (called_plugin);
 408   handle = handle;
 409   return LDPS_ERR;
 410 }
 411
 412 /* Return TRUE if a defined symbol might be reachable from outside the
 413    universe of claimed objects.  */
 414 static inline bfd_boolean
 415 is_visible_from_outside (struct ld_plugin_symbol *lsym, asection *section,
 416                          struct bfd_link_hash_entry *blhe)
 417 {
 418   /* Section's owner may be NULL if it is the absolute
 419      section, fortunately is_ir_dummy_bfd handles that.  */
 420   if (!is_ir_dummy_bfd (section->owner))
 421     return TRUE;
 422   if (link_info.relocatable)
 423     return TRUE;
 424   if (link_info.export_dynamic || link_info.shared)
 425     {
 426       /* Only ELF symbols really have visibility.  */
 427       if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
 428         {
 429           struct elf_link_hash_entry *el = (struct elf_link_hash_entry *)blhe;
 430           int vis = ELF_ST_VISIBILITY (el->other);
 431           return vis == STV_DEFAULT || vis == STV_PROTECTED;
 432         }
 433       /* On non-ELF targets, we can safely make inferences by considering
 434          what visibility the plugin would have liked to apply when it first
 435          sent us the symbol.  During ELF symbol processing, visibility only
 436          ever becomes more restrictive, not less, when symbols are merged,
 437          so this is a conservative estimate; it may give false positives,
 438          declaring something visible from outside when it in fact would
 439          not have been, but this will only lead to missed optimisation
 440          opportunities during LTRANS at worst; it will not give false
 441          negatives, which can lead to the disastrous conclusion that the
 442          related symbol is IRONLY.  (See GCC PR46319 for an example.)  */
 443       return (lsym->visibility == LDPV_DEFAULT
 444               || lsym->visibility == LDPV_PROTECTED);
 445     }
 446   return FALSE;
 447 }
 448
 449 /* Get the symbol resolution info for a plugin-claimed input file.  */
 450 static enum ld_plugin_status
 451 get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 452 {
 453   const bfd *abfd = handle;
 454   int n;
 455   ASSERT (called_plugin);
 456   for (n = 0; n < nsyms; n++)
 457     {
 458       struct bfd_link_hash_entry *blhe;
 459       bfd_boolean ironly;
 460       asection *owner_sec;
 461
 462       blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
 463                                    FALSE, FALSE, TRUE);
 464       if (!blhe)
 465         {
 466           syms[n].resolution = LDPR_UNKNOWN;
 467           continue;
 468         }
 469
 470       /* Determine resolution from blhe type and symbol's original type.  */
 471       if (blhe->type == bfd_link_hash_undefined
 472           || blhe->type == bfd_link_hash_undefweak)
 473         {
 474           syms[n].resolution = LDPR_UNDEF;
 475           continue;
 476         }
 477       if (blhe->type != bfd_link_hash_defined
 478           && blhe->type != bfd_link_hash_defweak
 479           && blhe->type != bfd_link_hash_common)
 480         {
 481           /* We should not have a new, indirect or warning symbol here.  */
 482           einfo ("%P%F: %s: plugin symbol table corrupt (sym type %d)\n",
 483                  called_plugin->name, blhe->type);
 484         }
 485
 486       /* Find out which section owns the symbol.  Since it's not undef,
 487          it must have an owner; if it's not a common symbol, both defs
 488          and weakdefs keep it in the same place. */
 489       owner_sec = (blhe->type == bfd_link_hash_common)
 490         ? blhe->u.c.p->section
 491         : blhe->u.def.section;
 492
 493       /* We need to know if the sym is referenced from non-IR files.  Or
 494          even potentially-referenced, perhaps in a future final link if
 495          this is a partial one, perhaps dynamically at load-time if the
 496          symbol is externally visible.  */
 497       ironly = !is_visible_from_outside (&syms[n], owner_sec, blhe)
 498         && !bfd_hash_lookup (non_ironly_hash, syms[n].name, FALSE, FALSE);
 499
 500       /* If it was originally undefined or common, then it has been
 501          resolved; determine how.  */
 502       if (syms[n].def == LDPK_UNDEF
 503           || syms[n].def == LDPK_WEAKUNDEF
 504           || syms[n].def == LDPK_COMMON)
 505         {
 506           if (owner_sec->owner == link_info.output_bfd)
 507             syms[n].resolution = LDPR_RESOLVED_EXEC;
 508           else if (owner_sec->owner == abfd)
 509             syms[n].resolution = (ironly
 510                                   ? LDPR_PREVAILING_DEF_IRONLY
 511                                   : LDPR_PREVAILING_DEF);
 512           else if (is_ir_dummy_bfd (owner_sec->owner))
 513             syms[n].resolution = LDPR_RESOLVED_IR;
 514           else if (owner_sec->owner->flags & DYNAMIC)
 515             syms[n].resolution =  LDPR_RESOLVED_DYN;
 516           else
 517             syms[n].resolution = LDPR_RESOLVED_EXEC;
 518           continue;
 519         }
 520
 521       /* Was originally def, or weakdef.  Does it prevail?  If the
 522          owner is the original dummy bfd that supplied it, then this
 523          is the definition that has prevailed.  */
 524       if (owner_sec->owner == link_info.output_bfd)
 525         syms[n].resolution = LDPR_PREEMPTED_REG;
 526       else if (owner_sec->owner == abfd)
 527         {
 528           syms[n].resolution = (ironly
 529                                 ? LDPR_PREVAILING_DEF_IRONLY
 530                                 : LDPR_PREVAILING_DEF);
 531           continue;
 532         }
 533
 534       /* Was originally def, weakdef, or common, but has been pre-empted.  */
 535       syms[n].resolution = is_ir_dummy_bfd (owner_sec->owner)
 536         ? LDPR_PREEMPTED_IR
 537         : LDPR_PREEMPTED_REG;
 538     }
 539   return LDPS_OK;
 540 }
 541
 542 /* Add a new (real) input file generated by a plugin.  */
 543 static enum ld_plugin_status
 544 add_input_file (const char *pathname)
 545 {
 546   ASSERT (called_plugin);
 547   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
 548                             NULL))
 549     return LDPS_ERR;
 550   return LDPS_OK;
 551 }
 552
 553 /* Add a new (real) library required by a plugin.  */
 554 static enum ld_plugin_status
 555 add_input_library (const char *pathname)
 556 {
 557   ASSERT (called_plugin);
 558   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
 559                             NULL))
 560     return LDPS_ERR;
 561   return LDPS_OK;
 562 }
 563
 564 /* Set the extra library path to be used by libraries added via
 565    add_input_library.  */
 566 static enum ld_plugin_status
 567 set_extra_library_path (const char *path)
 568 {
 569   ASSERT (called_plugin);
 570   ldfile_add_library_path (xstrdup (path), FALSE);
 571   return LDPS_OK;
 572 }
 573
 574 /* Issue a diagnostic message from a plugin.  */
 575 static enum ld_plugin_status
 576 message (int level, const char *format, ...)
 577 {
 578   va_list args;
 579   va_start (args, format);
 580
 581   switch (level)
 582     {
 583     case LDPL_INFO:
 584       vfinfo (stdout, format, args, FALSE);
 585       break;
 586     case LDPL_WARNING:
 587       vfinfo (stdout, format, args, TRUE);
 588       break;
 589     case LDPL_FATAL:
 590     case LDPL_ERROR:
 591     default:
 592         {
 593           char *newfmt = ACONCAT ((level == LDPL_FATAL
 594                                    ? "%P%F: " : "%P%X: ",
 595                                    format, "\n", NULL));
 596           vfinfo (stderr, newfmt, args, TRUE);
 597         }
 598       break;
 599     }
 600
 601   fputc('\n', stderr);
 602
 603   va_end (args);
 604   return LDPS_OK;
 605 }
 606
 607 /* Helper to size leading part of tv array and set it up. */
 608 static size_t
 609 set_tv_header (struct ld_plugin_tv *tv)
 610 {
 611   size_t i;
 612
 613   /* Version info.  */
 614   static const unsigned int major = (unsigned)(BFD_VERSION / 100000000UL);
 615   static const unsigned int minor = (unsigned)(BFD_VERSION / 1000000UL) % 100;
 616
 617   if (!tv)
 618     return tv_header_size;
 619
 620   for (i = 0; i < tv_header_size; i++)
 621     {
 622       tv[i].tv_tag = tv_header_tags[i];
 623 #define TVU(x) tv[i].tv_u.tv_ ## x
 624       switch (tv[i].tv_tag)
 625         {
 626         case LDPT_MESSAGE:
 627           TVU(message) = message;
 628           break;
 629         case LDPT_API_VERSION:
 630           TVU(val) = LD_PLUGIN_API_VERSION;
 631           break;
 632         case LDPT_GNU_LD_VERSION:
 633           TVU(val) = major * 100 + minor;
 634           break;
 635         case LDPT_LINKER_OUTPUT:
 636           TVU(val) = (link_info.relocatable
 637                       ? LDPO_REL
 638                       : (link_info.shared ? LDPO_DYN : LDPO_EXEC));
 639           break;
 640         case LDPT_OUTPUT_NAME:
 641           TVU(string) = output_filename;
 642           break;
 643         case LDPT_REGISTER_CLAIM_FILE_HOOK:
 644           TVU(register_claim_file) = register_claim_file;
 645           break;
 646         case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
 647           TVU(register_all_symbols_read) = register_all_symbols_read;
 648           break;
 649         case LDPT_REGISTER_CLEANUP_HOOK:
 650           TVU(register_cleanup) = register_cleanup;
 651           break;
 652         case LDPT_ADD_SYMBOLS:
 653           TVU(add_symbols) = add_symbols;
 654           break;
 655         case LDPT_GET_INPUT_FILE:
 656           TVU(get_input_file) = get_input_file;
 657           break;
 658         case LDPT_RELEASE_INPUT_FILE:
 659           TVU(release_input_file) = release_input_file;
 660           break;
 661         case LDPT_GET_SYMBOLS:
 662           TVU(get_symbols) = get_symbols;
 663           break;
 664         case LDPT_ADD_INPUT_FILE:
 665           TVU(add_input_file) = add_input_file;
 666           break;
 667         case LDPT_ADD_INPUT_LIBRARY:
 668           TVU(add_input_library) = add_input_library;
 669           break;
 670         case LDPT_SET_EXTRA_LIBRARY_PATH:
 671           TVU(set_extra_library_path) = set_extra_library_path;
 672           break;
 673         default:
 674           /* Added a new entry to the array without adding
 675              a new case to set up its value is a bug.  */
 676           FAIL ();
 677         }
 678 #undef TVU
 679     }
 680   return tv_header_size;
 681 }
 682
 683 /* Append the per-plugin args list and trailing LDPT_NULL to tv.  */
 684 static void
 685 set_tv_plugin_args (plugin_t *plugin, struct ld_plugin_tv *tv)
 686 {
 687   plugin_arg_t *arg = plugin->args;
 688   while (arg)
 689     {
 690       tv->tv_tag = LDPT_OPTION;
 691       tv->tv_u.tv_string = arg->arg;
 692       arg = arg->next;
 693       tv++;
 694     }
 695   tv->tv_tag = LDPT_NULL;
 696   tv->tv_u.tv_val = 0;
 697 }
 698
 699 /* Return true if any plugins are active this run.  Only valid
 700    after options have been processed.  */
 701 bfd_boolean
 702 plugin_active_plugins_p (void)
 703 {
 704   return plugins_list != NULL;
 705 }
 706
 707 /* Load up and initialise all plugins after argument parsing.  */
 708 int
 709 plugin_load_plugins (void)
 710 {
 711   struct ld_plugin_tv *my_tv;
 712   unsigned int max_args = 0;
 713   plugin_t *curplug = plugins_list;
 714
 715   /* If there are no plugins, we need do nothing this run.  */
 716   if (!curplug)
 717     return 0;
 718
 719   xatexit (plugin_call_cleanup);
 720
 721   /* First pass over plugins to find max # args needed so that we
 722      can size and allocate the tv array.  */
 723   while (curplug)
 724     {
 725       if (curplug->n_args > max_args)
 726         max_args = curplug->n_args;
 727       curplug = curplug->next;
 728     }
 729
 730   /* Allocate tv array and initialise constant part.  */
 731   my_tv = xmalloc ((max_args + 1 + tv_header_size) * sizeof *my_tv);
 732   set_tv_header (my_tv);
 733
 734   /* Pass over plugins again, activating them.  */
 735   curplug = plugins_list;
 736   while (curplug)
 737     {
 738       enum ld_plugin_status rv;
 739       ld_plugin_onload onloadfn = dlsym (curplug->dlhandle, "onload");
 740       if (!onloadfn)
 741         onloadfn = dlsym (curplug->dlhandle, "_onload");
 742       if (!onloadfn)
 743         return set_plugin_error (curplug->name);
 744       set_tv_plugin_args (curplug, &my_tv[tv_header_size]);
 745       called_plugin = curplug;
 746       rv = (*onloadfn) (my_tv);
 747       called_plugin = NULL;
 748       if (rv != LDPS_OK)
 749         return set_plugin_error (curplug->name);
 750       curplug = curplug->next;
 751     }
 752
 753   /* Since plugin(s) inited ok, assume they're going to want symbol
 754      resolutions, which needs us to track which symbols are referenced
 755      by non-IR files using the linker's notice callback.  */
 756   link_info.notice_all = TRUE;
 757
 758   return 0;
 759 }
 760
 761 /* Call 'claim file' hook for all plugins.  */
 762 int
 763 plugin_call_claim_file (const struct ld_plugin_input_file *file, int *claimed)
 764 {
 765   plugin_t *curplug = plugins_list;
 766   *claimed = FALSE;
 767   if (no_more_claiming)
 768     return 0;
 769   while (curplug && !*claimed)
 770     {
 771       if (curplug->claim_file_handler)
 772         {
 773           enum ld_plugin_status rv;
 774           called_plugin = curplug;
 775           rv = (*curplug->claim_file_handler) (file, claimed);
 776           called_plugin = NULL;
 777           if (rv != LDPS_OK)
 778             set_plugin_error (curplug->name);
 779         }
 780       curplug = curplug->next;
 781     }
 782   return plugin_error_p () ? -1 : 0;
 783 }
 784
 785 /* Call 'all symbols read' hook for all plugins.  */
 786 int
 787 plugin_call_all_symbols_read (void)
 788 {
 789   plugin_t *curplug = plugins_list;
 790
 791   /* Disable any further file-claiming.  */
 792   no_more_claiming = TRUE;
 793
 794   /* If --allow-multiple-definition is in effect, we need to disable it,
 795      as the plugin infrastructure relies on the multiple_definition
 796      callback to swap out the dummy IR-only BFDs for new real ones
 797      when it starts opening the files added during this callback.  */
 798   plugin_cached_allow_multiple_defs = link_info.allow_multiple_definition;
 799   link_info.allow_multiple_definition = FALSE;
 800
 801   while (curplug)
 802     {
 803       if (curplug->all_symbols_read_handler)
 804         {
 805           enum ld_plugin_status rv;
 806           called_plugin = curplug;
 807           rv = (*curplug->all_symbols_read_handler) ();
 808           called_plugin = NULL;
 809           if (rv != LDPS_OK)
 810             set_plugin_error (curplug->name);
 811         }
 812       curplug = curplug->next;
 813     }
 814   return plugin_error_p () ? -1 : 0;
 815 }
 816
 817 /* Call 'cleanup' hook for all plugins at exit.  */
 818 static void
 819 plugin_call_cleanup (void)
 820 {
 821   plugin_t *curplug = plugins_list;
 822   while (curplug)
 823     {
 824       if (curplug->cleanup_handler && !curplug->cleanup_done)
 825         {
 826           enum ld_plugin_status rv;
 827           curplug->cleanup_done = TRUE;
 828           called_plugin = curplug;
 829           rv = (*curplug->cleanup_handler) ();
 830           called_plugin = NULL;
 831           if (rv != LDPS_OK)
 832             set_plugin_error (curplug->name);
 833           dlclose (curplug->dlhandle);
 834         }
 835       curplug = curplug->next;
 836     }
 837   if (plugin_error_p ())
 838     info_msg (_("%P: %s: error in plugin cleanup (ignored)\n"),
 839               plugin_error_plugin ());
 840 }
 841
 842 /* Lazily init the non_ironly hash table.  */
 843 static void
 844 init_non_ironly_hash (void)
 845 {
 846   if (non_ironly_hash == NULL)
 847     {
 848       non_ironly_hash =
 849         (struct bfd_hash_table *) xmalloc (sizeof (struct bfd_hash_table));
 850       if (!bfd_hash_table_init_n (non_ironly_hash,
 851                                   bfd_hash_newfunc,
 852                                   sizeof (struct bfd_hash_entry),
 853                                   61))
 854         einfo (_("%P%F: bfd_hash_table_init failed: %E\n"));
 855     }
 856 }
 857
 858 /* To determine which symbols should be resolved LDPR_PREVAILING_DEF
 859    and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
 860    the linker adds them to the linker hash table.  If we see a symbol
 861    being referenced from a non-IR file, we add it to the non_ironly hash
 862    table.  If we can't find it there at get_symbols time, we know that
 863    it was referenced only by IR files.  We have to notice_all symbols,
 864    because we won't necessarily know until later which ones will be
 865    contributed by IR files.  */
 866 bfd_boolean
 867 plugin_notice (struct bfd_link_info *info ATTRIBUTE_UNUSED,
 868                const char *name, bfd *abfd,
 869                asection *section, bfd_vma value ATTRIBUTE_UNUSED)
 870 {
 871   bfd_boolean is_ref = bfd_is_und_section (section);
 872   bfd_boolean is_dummy = is_ir_dummy_bfd (abfd);
 873   init_non_ironly_hash ();
 874   /* We only care about refs, not defs, indicated by section pointing
 875      to the undefined section (according to the bfd linker notice callback
 876      interface definition).  */
 877   if (is_ref && !is_dummy)
 878     {
 879       /* This is a ref from a non-IR file, so note the ref'd symbol
 880          in the non-IR-only hash.  */
 881       if (!bfd_hash_lookup (non_ironly_hash, name, TRUE, TRUE))
 882         einfo (_("%P%X: %s: hash table failure adding symbol %s\n"),
 883                abfd->filename, name);
 884     }
 885   else if (!is_ref && is_dummy)
 886     {
 887       /* No further processing since this is a def from an IR dummy BFD.  */
 888       return FALSE;
 889     }
 890
 891   /* Continue with cref/nocrossref/trace-sym processing.  */
 892   return TRUE;
 893 }
 894
 895 /* When we add new object files to the link at all symbols read time,
 896    these contain the real code and symbols generated from the IR files,
 897    and so duplicate all the definitions already supplied by the dummy
 898    IR-only BFDs that we created at claim files time.  We use the linker's
 899    multiple-definitions callback hook to fix up the clash, discarding
 900    the symbol from the IR-only BFD in favour of the symbol from the
 901    real BFD.  We return true if this was not-really-a-clash because
 902    we've fixed it up, or anyway if --allow-multiple-definition was in
 903    effect (before we disabled it to ensure we got called back).  */
 904 bfd_boolean
 905 plugin_multiple_definition (struct bfd_link_info *info, const char *name,
 906                             bfd *obfd, asection *osec ATTRIBUTE_UNUSED,
 907                             bfd_vma oval ATTRIBUTE_UNUSED,
 908                             bfd *nbfd, asection *nsec, bfd_vma nval)
 909 {
 910   if (is_ir_dummy_bfd (obfd))
 911     {
 912       struct bfd_link_hash_entry *blhe
 913         = bfd_link_hash_lookup (info->hash, name, FALSE, FALSE, FALSE);
 914       if (!blhe)
 915         einfo (_("%P%X: %s: can't find IR symbol '%s'\n"), nbfd->filename,
 916                name);
 917       else if (blhe->type != bfd_link_hash_defined)
 918         einfo (_("%P%x: %s: bad IR symbol type %d\n"), name, blhe->type);
 919       /* Replace it with new details.  */
 920       blhe->u.def.section = nsec;
 921       blhe->u.def.value = nval;
 922       return TRUE;
 923     }
 924   return plugin_cached_allow_multiple_defs;
 925 }