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 /* 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   bfd_copy_private_bfd_data (srctemplate, abfd);
 241   bfd_set_gp_size (abfd, bfd_get_gp_size (abfd));
 242   /* Create a minimal set of sections to own the symbols.  */
 243   sec = bfd_make_section_old_way (abfd, ".text");
 244   bfd_set_section_flags (abfd, sec,
 245                          (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 246                           | SEC_ALLOC | SEC_LOAD | SEC_KEEP));
 247   sec->output_section = sec;
 248   sec->output_offset = 0;
 249   return abfd;
 250 }
 251
 252 /* Check if the BFD passed in is an IR dummy object file.  */
 253 static bfd_boolean
 254 is_ir_dummy_bfd (const bfd *abfd)
 255 {
 256   size_t namlen;
 257
 258   if (abfd == NULL)
 259     return FALSE;
 260   namlen = strlen (abfd->filename);
 261   if (namlen < IRONLY_SUFFIX_LEN)
 262     return FALSE;
 263   return !strcmp (abfd->filename + namlen - IRONLY_SUFFIX_LEN, IRONLY_SUFFIX);
 264 }
 265
 266 /* Helpers to convert between BFD and GOLD symbol formats.  */
 267 static enum ld_plugin_status
 268 asymbol_from_plugin_symbol (bfd *abfd, asymbol *asym,
 269                             const struct ld_plugin_symbol *ldsym)
 270 {
 271   flagword flags = BSF_NO_FLAGS;
 272   struct bfd_section *section;
 273
 274   asym->the_bfd = abfd;
 275   asym->name = (ldsym->version
 276                 ? concat (ldsym->name, "@", ldsym->version, NULL)
 277                 : ldsym->name);
 278   asym->value = 0;
 279   switch (ldsym->def)
 280     {
 281     case LDPK_WEAKDEF:
 282       flags = BSF_WEAK;
 283       /* FALLTHRU */
 284     case LDPK_DEF:
 285       flags |= BSF_GLOBAL;
 286       section = bfd_get_section_by_name (abfd, ".text");
 287       break;
 288
 289     case LDPK_WEAKUNDEF:
 290       flags = BSF_WEAK;
 291       /* FALLTHRU */
 292     case LDPK_UNDEF:
 293       section = bfd_und_section_ptr;
 294       break;
 295
 296     case LDPK_COMMON:
 297       flags = BSF_GLOBAL;
 298       section = bfd_com_section_ptr;
 299       asym->value = ldsym->size;
 300       /* For ELF targets, set alignment of common symbol to 1.  */
 301       if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 302         ((elf_symbol_type *) asym)->internal_elf_sym.st_value = 1;
 303       break;
 304
 305     default:
 306       return LDPS_ERR;
 307     }
 308   asym->flags = flags;
 309   asym->section = section;
 310
 311   /* Visibility only applies on ELF targets.  */
 312   if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 313     {
 314       elf_symbol_type *elfsym = elf_symbol_from (abfd, asym);
 315       unsigned char visibility;
 316
 317       if (!elfsym)
 318         einfo (_("%P%F: %s: non-ELF symbol in ELF BFD!\n"), asym->name);
 319       switch (ldsym->visibility)
 320         {
 321         default:
 322           einfo (_("%P%F: unknown ELF symbol visibility: %d!\n"),
 323                  ldsym->visibility);
 324         case LDPV_DEFAULT:
 325           visibility = STV_DEFAULT;
 326           break;
 327         case LDPV_PROTECTED:
 328           visibility = STV_PROTECTED;
 329           break;
 330         case LDPV_INTERNAL:
 331           visibility = STV_INTERNAL;
 332           break;
 333         case LDPV_HIDDEN:
 334           visibility = STV_HIDDEN;
 335           break;
 336         }
 337       elfsym->internal_elf_sym.st_other
 338         = (visibility | (elfsym->internal_elf_sym.st_other
 339                          & ~ELF_ST_VISIBILITY (-1)));
 340     }
 341
 342   return LDPS_OK;
 343 }
 344
 345 /* Register a claim-file handler.  */
 346 static enum ld_plugin_status
 347 register_claim_file (ld_plugin_claim_file_handler handler)
 348 {
 349   ASSERT (called_plugin);
 350   called_plugin->claim_file_handler = handler;
 351   return LDPS_OK;
 352 }
 353
 354 /* Register an all-symbols-read handler.  */
 355 static enum ld_plugin_status
 356 register_all_symbols_read (ld_plugin_all_symbols_read_handler handler)
 357 {
 358   ASSERT (called_plugin);
 359   called_plugin->all_symbols_read_handler = handler;
 360   return LDPS_OK;
 361 }
 362
 363 /* Register a cleanup handler.  */
 364 static enum ld_plugin_status
 365 register_cleanup (ld_plugin_cleanup_handler handler)
 366 {
 367   ASSERT (called_plugin);
 368   called_plugin->cleanup_handler = handler;
 369   return LDPS_OK;
 370 }
 371
 372 /* Add symbols from a plugin-claimed input file.  */
 373 static enum ld_plugin_status
 374 add_symbols (void *handle, int nsyms, const struct ld_plugin_symbol *syms)
 375 {
 376   asymbol **symptrs;
 377   bfd *abfd = handle;
 378   int n;
 379   ASSERT (called_plugin);
 380   symptrs = xmalloc (nsyms * sizeof *symptrs);
 381   for (n = 0; n < nsyms; n++)
 382     {
 383       enum ld_plugin_status rv;
 384       asymbol *bfdsym = bfd_make_empty_symbol (abfd);
 385       symptrs[n] = bfdsym;
 386       rv = asymbol_from_plugin_symbol (abfd, bfdsym, syms + n);
 387       if (rv != LDPS_OK)
 388         return rv;
 389     }
 390   bfd_set_symtab (abfd, symptrs, nsyms);
 391   return LDPS_OK;
 392 }
 393
 394 /* Get the input file information with an open (possibly re-opened)
 395    file descriptor.  */
 396 static enum ld_plugin_status
 397 get_input_file (const void *handle, struct ld_plugin_input_file *file)
 398 {
 399   ASSERT (called_plugin);
 400   handle = handle;
 401   file = file;
 402   return LDPS_ERR;
 403 }
 404
 405 /* Release the input file.  */
 406 static enum ld_plugin_status
 407 release_input_file (const void *handle)
 408 {
 409   ASSERT (called_plugin);
 410   handle = handle;
 411   return LDPS_ERR;
 412 }
 413
 414 /* Return TRUE if a defined symbol might be reachable from outside the
 415    universe of claimed objects.  */
 416 static inline bfd_boolean
 417 is_visible_from_outside (struct ld_plugin_symbol *lsym, asection *section,
 418                          struct bfd_link_hash_entry *blhe)
 419 {
 420   /* Section's owner may be NULL if it is the absolute
 421      section, fortunately is_ir_dummy_bfd handles that.  */
 422   if (!is_ir_dummy_bfd (section->owner))
 423     return TRUE;
 424   if (link_info.relocatable)
 425     return TRUE;
 426   if (link_info.export_dynamic || link_info.shared)
 427     {
 428       /* Only ELF symbols really have visibility.  */
 429       if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
 430         {
 431           struct elf_link_hash_entry *el = (struct elf_link_hash_entry *)blhe;
 432           int vis = ELF_ST_VISIBILITY (el->other);
 433           return vis == STV_DEFAULT || vis == STV_PROTECTED;
 434         }
 435       /* On non-ELF targets, we can safely make inferences by considering
 436          what visibility the plugin would have liked to apply when it first
 437          sent us the symbol.  During ELF symbol processing, visibility only
 438          ever becomes more restrictive, not less, when symbols are merged,
 439          so this is a conservative estimate; it may give false positives,
 440          declaring something visible from outside when it in fact would
 441          not have been, but this will only lead to missed optimisation
 442          opportunities during LTRANS at worst; it will not give false
 443          negatives, which can lead to the disastrous conclusion that the
 444          related symbol is IRONLY.  (See GCC PR46319 for an example.)  */
 445       return (lsym->visibility == LDPV_DEFAULT
 446               || lsym->visibility == LDPV_PROTECTED);
 447     }
 448   return FALSE;
 449 }
 450
 451 /* Get the symbol resolution info for a plugin-claimed input file.  */
 452 static enum ld_plugin_status
 453 get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 454 {
 455   const bfd *abfd = handle;
 456   int n;
 457   ASSERT (called_plugin);
 458   for (n = 0; n < nsyms; n++)
 459     {
 460       struct bfd_link_hash_entry *blhe;
 461       bfd_boolean ironly;
 462       asection *owner_sec;
 463
 464       blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
 465                                    FALSE, FALSE, TRUE);
 466       if (!blhe)
 467         {
 468           syms[n].resolution = LDPR_UNKNOWN;
 469           continue;
 470         }
 471
 472       /* Determine resolution from blhe type and symbol's original type.  */
 473       if (blhe->type == bfd_link_hash_undefined
 474           || blhe->type == bfd_link_hash_undefweak)
 475         {
 476           syms[n].resolution = LDPR_UNDEF;
 477           continue;
 478         }
 479       if (blhe->type != bfd_link_hash_defined
 480           && blhe->type != bfd_link_hash_defweak
 481           && blhe->type != bfd_link_hash_common)
 482         {
 483           /* We should not have a new, indirect or warning symbol here.  */
 484           einfo ("%P%F: %s: plugin symbol table corrupt (sym type %d)\n",
 485                  called_plugin->name, blhe->type);
 486         }
 487
 488       /* Find out which section owns the symbol.  Since it's not undef,
 489          it must have an owner; if it's not a common symbol, both defs
 490          and weakdefs keep it in the same place. */
 491       owner_sec = (blhe->type == bfd_link_hash_common)
 492         ? blhe->u.c.p->section
 493         : blhe->u.def.section;
 494
 495       /* We need to know if the sym is referenced from non-IR files.  Or
 496          even potentially-referenced, perhaps in a future final link if
 497          this is a partial one, perhaps dynamically at load-time if the
 498          symbol is externally visible.  */
 499       ironly = !is_visible_from_outside (&syms[n], owner_sec, blhe)
 500         && !bfd_hash_lookup (non_ironly_hash, syms[n].name, FALSE, FALSE);
 501
 502       /* If it was originally undefined or common, then it has been
 503          resolved; determine how.  */
 504       if (syms[n].def == LDPK_UNDEF
 505           || syms[n].def == LDPK_WEAKUNDEF
 506           || syms[n].def == LDPK_COMMON)
 507         {
 508           if (owner_sec->owner == link_info.output_bfd)
 509             syms[n].resolution = LDPR_RESOLVED_EXEC;
 510           else if (owner_sec->owner == abfd)
 511             syms[n].resolution = (ironly
 512                                   ? LDPR_PREVAILING_DEF_IRONLY
 513                                   : LDPR_PREVAILING_DEF);
 514           else if (is_ir_dummy_bfd (owner_sec->owner))
 515             syms[n].resolution = LDPR_RESOLVED_IR;
 516           else if (owner_sec->owner != NULL
 517                    && (owner_sec->owner->flags & DYNAMIC) != 0)
 518             syms[n].resolution =  LDPR_RESOLVED_DYN;
 519           else
 520             syms[n].resolution = LDPR_RESOLVED_EXEC;
 521           continue;
 522         }
 523
 524       /* Was originally def, or weakdef.  Does it prevail?  If the
 525          owner is the original dummy bfd that supplied it, then this
 526          is the definition that has prevailed.  */
 527       if (owner_sec->owner == link_info.output_bfd)
 528         syms[n].resolution = LDPR_PREEMPTED_REG;
 529       else if (owner_sec->owner == abfd)
 530         {
 531           syms[n].resolution = (ironly
 532                                 ? LDPR_PREVAILING_DEF_IRONLY
 533                                 : LDPR_PREVAILING_DEF);
 534           continue;
 535         }
 536
 537       /* Was originally def, weakdef, or common, but has been pre-empted.  */
 538       syms[n].resolution = is_ir_dummy_bfd (owner_sec->owner)
 539         ? LDPR_PREEMPTED_IR
 540         : LDPR_PREEMPTED_REG;
 541     }
 542   return LDPS_OK;
 543 }
 544
 545 /* Add a new (real) input file generated by a plugin.  */
 546 static enum ld_plugin_status
 547 add_input_file (const char *pathname)
 548 {
 549   ASSERT (called_plugin);
 550   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
 551                             NULL))
 552     return LDPS_ERR;
 553   return LDPS_OK;
 554 }
 555
 556 /* Add a new (real) library required by a plugin.  */
 557 static enum ld_plugin_status
 558 add_input_library (const char *pathname)
 559 {
 560   ASSERT (called_plugin);
 561   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
 562                             NULL))
 563     return LDPS_ERR;
 564   return LDPS_OK;
 565 }
 566
 567 /* Set the extra library path to be used by libraries added via
 568    add_input_library.  */
 569 static enum ld_plugin_status
 570 set_extra_library_path (const char *path)
 571 {
 572   ASSERT (called_plugin);
 573   ldfile_add_library_path (xstrdup (path), FALSE);
 574   return LDPS_OK;
 575 }
 576
 577 /* Issue a diagnostic message from a plugin.  */
 578 static enum ld_plugin_status
 579 message (int level, const char *format, ...)
 580 {
 581   va_list args;
 582   va_start (args, format);
 583
 584   switch (level)
 585     {
 586     case LDPL_INFO:
 587       vfinfo (stdout, format, args, FALSE);
 588       putchar ('\n');
 589       break;
 590     case LDPL_WARNING:
 591       vfinfo (stdout, format, args, TRUE);
 592       putchar ('\n');
 593       break;
 594     case LDPL_FATAL:
 595     case LDPL_ERROR:
 596     default:
 597         {
 598           char *newfmt = ACONCAT ((level == LDPL_FATAL
 599                                    ? "%P%F: " : "%P%X: ",
 600                                    format, "\n", NULL));
 601           fflush (stdout);
 602           vfinfo (stderr, newfmt, args, TRUE);
 603           fflush (stderr);
 604         }
 605       break;
 606     }
 607
 608   va_end (args);
 609   return LDPS_OK;
 610 }
 611
 612 /* Helper to size leading part of tv array and set it up. */
 613 static size_t
 614 set_tv_header (struct ld_plugin_tv *tv)
 615 {
 616   size_t i;
 617
 618   /* Version info.  */
 619   static const unsigned int major = (unsigned)(BFD_VERSION / 100000000UL);
 620   static const unsigned int minor = (unsigned)(BFD_VERSION / 1000000UL) % 100;
 621
 622   if (!tv)
 623     return tv_header_size;
 624
 625   for (i = 0; i < tv_header_size; i++)
 626     {
 627       tv[i].tv_tag = tv_header_tags[i];
 628 #define TVU(x) tv[i].tv_u.tv_ ## x
 629       switch (tv[i].tv_tag)
 630         {
 631         case LDPT_MESSAGE:
 632           TVU(message) = message;
 633           break;
 634         case LDPT_API_VERSION:
 635           TVU(val) = LD_PLUGIN_API_VERSION;
 636           break;
 637         case LDPT_GNU_LD_VERSION:
 638           TVU(val) = major * 100 + minor;
 639           break;
 640         case LDPT_LINKER_OUTPUT:
 641           TVU(val) = (link_info.relocatable
 642                       ? LDPO_REL
 643                       : (link_info.shared ? LDPO_DYN : LDPO_EXEC));
 644           break;
 645         case LDPT_OUTPUT_NAME:
 646           TVU(string) = output_filename;
 647           break;
 648         case LDPT_REGISTER_CLAIM_FILE_HOOK:
 649           TVU(register_claim_file) = register_claim_file;
 650           break;
 651         case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
 652           TVU(register_all_symbols_read) = register_all_symbols_read;
 653           break;
 654         case LDPT_REGISTER_CLEANUP_HOOK:
 655           TVU(register_cleanup) = register_cleanup;
 656           break;
 657         case LDPT_ADD_SYMBOLS:
 658           TVU(add_symbols) = add_symbols;
 659           break;
 660         case LDPT_GET_INPUT_FILE:
 661           TVU(get_input_file) = get_input_file;
 662           break;
 663         case LDPT_RELEASE_INPUT_FILE:
 664           TVU(release_input_file) = release_input_file;
 665           break;
 666         case LDPT_GET_SYMBOLS:
 667           TVU(get_symbols) = get_symbols;
 668           break;
 669         case LDPT_ADD_INPUT_FILE:
 670           TVU(add_input_file) = add_input_file;
 671           break;
 672         case LDPT_ADD_INPUT_LIBRARY:
 673           TVU(add_input_library) = add_input_library;
 674           break;
 675         case LDPT_SET_EXTRA_LIBRARY_PATH:
 676           TVU(set_extra_library_path) = set_extra_library_path;
 677           break;
 678         default:
 679           /* Added a new entry to the array without adding
 680              a new case to set up its value is a bug.  */
 681           FAIL ();
 682         }
 683 #undef TVU
 684     }
 685   return tv_header_size;
 686 }
 687
 688 /* Append the per-plugin args list and trailing LDPT_NULL to tv.  */
 689 static void
 690 set_tv_plugin_args (plugin_t *plugin, struct ld_plugin_tv *tv)
 691 {
 692   plugin_arg_t *arg = plugin->args;
 693   while (arg)
 694     {
 695       tv->tv_tag = LDPT_OPTION;
 696       tv->tv_u.tv_string = arg->arg;
 697       arg = arg->next;
 698       tv++;
 699     }
 700   tv->tv_tag = LDPT_NULL;
 701   tv->tv_u.tv_val = 0;
 702 }
 703
 704 /* Return true if any plugins are active this run.  Only valid
 705    after options have been processed.  */
 706 bfd_boolean
 707 plugin_active_plugins_p (void)
 708 {
 709   return plugins_list != NULL;
 710 }
 711
 712 /* Load up and initialise all plugins after argument parsing.  */
 713 int
 714 plugin_load_plugins (void)
 715 {
 716   struct ld_plugin_tv *my_tv;
 717   unsigned int max_args = 0;
 718   plugin_t *curplug = plugins_list;
 719
 720   /* If there are no plugins, we need do nothing this run.  */
 721   if (!curplug)
 722     return 0;
 723
 724   xatexit (plugin_call_cleanup);
 725
 726   /* First pass over plugins to find max # args needed so that we
 727      can size and allocate the tv array.  */
 728   while (curplug)
 729     {
 730       if (curplug->n_args > max_args)
 731         max_args = curplug->n_args;
 732       curplug = curplug->next;
 733     }
 734
 735   /* Allocate tv array and initialise constant part.  */
 736   my_tv = xmalloc ((max_args + 1 + tv_header_size) * sizeof *my_tv);
 737   set_tv_header (my_tv);
 738
 739   /* Pass over plugins again, activating them.  */
 740   curplug = plugins_list;
 741   while (curplug)
 742     {
 743       enum ld_plugin_status rv;
 744       ld_plugin_onload onloadfn = dlsym (curplug->dlhandle, "onload");
 745       if (!onloadfn)
 746         onloadfn = dlsym (curplug->dlhandle, "_onload");
 747       if (!onloadfn)
 748         return set_plugin_error (curplug->name);
 749       set_tv_plugin_args (curplug, &my_tv[tv_header_size]);
 750       called_plugin = curplug;
 751       rv = (*onloadfn) (my_tv);
 752       called_plugin = NULL;
 753       if (rv != LDPS_OK)
 754         return set_plugin_error (curplug->name);
 755       curplug = curplug->next;
 756     }
 757
 758   /* Since plugin(s) inited ok, assume they're going to want symbol
 759      resolutions, which needs us to track which symbols are referenced
 760      by non-IR files using the linker's notice callback.  */
 761   link_info.notice_all = TRUE;
 762
 763   return 0;
 764 }
 765
 766 /* Call 'claim file' hook for all plugins.  */
 767 int
 768 plugin_call_claim_file (const struct ld_plugin_input_file *file, int *claimed)
 769 {
 770   plugin_t *curplug = plugins_list;
 771   *claimed = FALSE;
 772   if (no_more_claiming)
 773     return 0;
 774   while (curplug && !*claimed)
 775     {
 776       if (curplug->claim_file_handler)
 777         {
 778           enum ld_plugin_status rv;
 779           called_plugin = curplug;
 780           rv = (*curplug->claim_file_handler) (file, claimed);
 781           called_plugin = NULL;
 782           if (rv != LDPS_OK)
 783             set_plugin_error (curplug->name);
 784         }
 785       curplug = curplug->next;
 786     }
 787   return plugin_error_p () ? -1 : 0;
 788 }
 789
 790 /* Call 'all symbols read' hook for all plugins.  */
 791 int
 792 plugin_call_all_symbols_read (void)
 793 {
 794   plugin_t *curplug = plugins_list;
 795
 796   /* Disable any further file-claiming.  */
 797   no_more_claiming = TRUE;
 798
 799   /* If --allow-multiple-definition is in effect, we need to disable it,
 800      as the plugin infrastructure relies on the multiple_definition
 801      callback to swap out the dummy IR-only BFDs for new real ones
 802      when it starts opening the files added during this callback.  */
 803   plugin_cached_allow_multiple_defs = link_info.allow_multiple_definition;
 804   link_info.allow_multiple_definition = FALSE;
 805
 806   while (curplug)
 807     {
 808       if (curplug->all_symbols_read_handler)
 809         {
 810           enum ld_plugin_status rv;
 811           called_plugin = curplug;
 812           rv = (*curplug->all_symbols_read_handler) ();
 813           called_plugin = NULL;
 814           if (rv != LDPS_OK)
 815             set_plugin_error (curplug->name);
 816         }
 817       curplug = curplug->next;
 818     }
 819   return plugin_error_p () ? -1 : 0;
 820 }
 821
 822 /* Call 'cleanup' hook for all plugins at exit.  */
 823 static void
 824 plugin_call_cleanup (void)
 825 {
 826   plugin_t *curplug = plugins_list;
 827   while (curplug)
 828     {
 829       if (curplug->cleanup_handler && !curplug->cleanup_done)
 830         {
 831           enum ld_plugin_status rv;
 832           curplug->cleanup_done = TRUE;
 833           called_plugin = curplug;
 834           rv = (*curplug->cleanup_handler) ();
 835           called_plugin = NULL;
 836           if (rv != LDPS_OK)
 837             set_plugin_error (curplug->name);
 838           dlclose (curplug->dlhandle);
 839         }
 840       curplug = curplug->next;
 841     }
 842   if (plugin_error_p ())
 843     info_msg (_("%P: %s: error in plugin cleanup (ignored)\n"),
 844               plugin_error_plugin ());
 845 }
 846
 847 /* Lazily init the non_ironly hash table.  */
 848 static void
 849 init_non_ironly_hash (void)
 850 {
 851   if (non_ironly_hash == NULL)
 852     {
 853       non_ironly_hash =
 854         (struct bfd_hash_table *) xmalloc (sizeof (struct bfd_hash_table));
 855       if (!bfd_hash_table_init_n (non_ironly_hash,
 856                                   bfd_hash_newfunc,
 857                                   sizeof (struct bfd_hash_entry),
 858                                   61))
 859         einfo (_("%P%F: bfd_hash_table_init failed: %E\n"));
 860     }
 861 }
 862
 863 /* To determine which symbols should be resolved LDPR_PREVAILING_DEF
 864    and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
 865    the linker adds them to the linker hash table.  If we see a symbol
 866    being referenced from a non-IR file, we add it to the non_ironly hash
 867    table.  If we can't find it there at get_symbols time, we know that
 868    it was referenced only by IR files.  We have to notice_all symbols,
 869    because we won't necessarily know until later which ones will be
 870    contributed by IR files.  */
 871 bfd_boolean
 872 plugin_notice (struct bfd_link_info *info ATTRIBUTE_UNUSED,
 873                const char *name, bfd *abfd,
 874                asection *section, bfd_vma value ATTRIBUTE_UNUSED)
 875 {
 876   bfd_boolean is_ref = bfd_is_und_section (section);
 877   bfd_boolean is_dummy = is_ir_dummy_bfd (abfd);
 878   init_non_ironly_hash ();
 879   /* We only care about refs, not defs, indicated by section pointing
 880      to the undefined section (according to the bfd linker notice callback
 881      interface definition).  */
 882   if (is_ref && !is_dummy)
 883     {
 884       /* This is a ref from a non-IR file, so note the ref'd symbol
 885          in the non-IR-only hash.  */
 886       if (!bfd_hash_lookup (non_ironly_hash, name, TRUE, TRUE))
 887         einfo (_("%P%X: %s: hash table failure adding symbol %s\n"),
 888                abfd->filename, name);
 889     }
 890   else if (!is_ref && is_dummy)
 891     {
 892       /* No further processing since this is a def from an IR dummy BFD.  */
 893       return FALSE;
 894     }
 895
 896   /* Continue with cref/nocrossref/trace-sym processing.  */
 897   return TRUE;
 898 }
 899
 900 /* When we add new object files to the link at all symbols read time,
 901    these contain the real code and symbols generated from the IR files,
 902    and so duplicate all the definitions already supplied by the dummy
 903    IR-only BFDs that we created at claim files time.  We use the linker's
 904    multiple-definitions callback hook to fix up the clash, discarding
 905    the symbol from the IR-only BFD in favour of the symbol from the
 906    real BFD.  We return true if this was not-really-a-clash because
 907    we've fixed it up, or anyway if --allow-multiple-definition was in
 908    effect (before we disabled it to ensure we got called back).  */
 909 bfd_boolean
 910 plugin_multiple_definition (struct bfd_link_info *info, const char *name,
 911                             bfd *obfd, asection *osec ATTRIBUTE_UNUSED,
 912                             bfd_vma oval ATTRIBUTE_UNUSED,
 913                             bfd *nbfd, asection *nsec, bfd_vma nval)
 914 {
 915   if (is_ir_dummy_bfd (obfd))
 916     {
 917       struct bfd_link_hash_entry *blhe
 918         = bfd_link_hash_lookup (info->hash, name, FALSE, FALSE, FALSE);
 919       if (!blhe)
 920         einfo (_("%P%X: %s: can't find IR symbol '%s'\n"), nbfd->filename,
 921                name);
 922       else if (blhe->type != bfd_link_hash_defined)
 923         einfo (_("%P%x: %s: bad IR symbol type %d\n"), name, blhe->type);
 924       /* Replace it with new details.  */
 925       blhe->u.def.section = nsec;
 926       blhe->u.def.value = nval;
 927       return TRUE;
 928     }
 929   return plugin_cached_allow_multiple_defs;
 930 }