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 /* List of tags to set in the constant leading part of the tv array. */
 112 static const enum ld_plugin_tag tv_header_tags[] =
 113 {
 114   LDPT_MESSAGE,
 115   LDPT_API_VERSION,
 116   LDPT_GNU_LD_VERSION,
 117   LDPT_LINKER_OUTPUT,
 118   LDPT_OUTPUT_NAME,
 119   LDPT_REGISTER_CLAIM_FILE_HOOK,
 120   LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
 121   LDPT_REGISTER_CLEANUP_HOOK,
 122   LDPT_ADD_SYMBOLS,
 123   LDPT_GET_INPUT_FILE,
 124   LDPT_RELEASE_INPUT_FILE,
 125   LDPT_GET_SYMBOLS,
 126   LDPT_ADD_INPUT_FILE,
 127   LDPT_ADD_INPUT_LIBRARY,
 128   LDPT_SET_EXTRA_LIBRARY_PATH
 129 };
 130
 131 /* How many entries in the constant leading part of the tv array.  */
 132 static const size_t tv_header_size = ARRAY_SIZE (tv_header_tags);
 133
 134 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
 135
 136 #define RTLD_NOW 0      /* Dummy value.  */
 137
 138 static void *
 139 dlopen (const char *file, int mode ATTRIBUTE_UNUSED)
 140 {
 141   return LoadLibrary (file);
 142 }
 143
 144 static void *
 145 dlsym (void *handle, const char *name)
 146 {
 147   return GetProcAddress (handle, name);
 148 }
 149
 150 static int
 151 dlclose (void *handle)
 152 {
 153   FreeLibrary (handle);
 154   return 0;
 155 }
 156
 157 #endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)  */
 158
 159 /* Helper function for exiting with error status.  */
 160 static int
 161 set_plugin_error (const char *plugin)
 162 {
 163   error_plugin = plugin;
 164   return -1;
 165 }
 166
 167 /* Test if an error occurred.  */
 168 static bfd_boolean
 169 plugin_error_p (void)
 170 {
 171   return error_plugin != NULL;
 172 }
 173
 174 /* Return name of plugin which caused an error if any.  */
 175 const char *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 plugin_opt_plugin (const char *plugin)
 182 {
 183   plugin_t *newplug;
 184
 185   newplug = xmalloc (sizeof *newplug);
 186   memset (newplug, 0, sizeof *newplug);
 187   newplug->name = plugin;
 188   newplug->dlhandle = dlopen (plugin, RTLD_NOW);
 189   if (!newplug->dlhandle)
 190     return set_plugin_error (plugin);
 191
 192   /* Chain on end, so when we run list it is in command-line order.  */
 193   *plugins_tail_chain_ptr = newplug;
 194   plugins_tail_chain_ptr = &newplug->next;
 195
 196   /* Record it as current plugin for receiving args.  */
 197   last_plugin = newplug;
 198   last_plugin_args_tail_chain_ptr = &newplug->args;
 199   return 0;
 200 }
 201
 202 /* Accumulate option arguments for last-loaded plugin, or return
 203    error if none.  */
 204 int plugin_opt_plugin_arg (const char *arg)
 205 {
 206   plugin_arg_t *newarg;
 207
 208   if (!last_plugin)
 209     return set_plugin_error (_("<no plugin>"));
 210
 211   newarg = xmalloc (sizeof *newarg);
 212   newarg->arg = arg;
 213   newarg->next = NULL;
 214
 215   /* Chain on end to preserve command-line order.  */
 216   *last_plugin_args_tail_chain_ptr = newarg;
 217   last_plugin_args_tail_chain_ptr = &newarg->next;
 218   last_plugin->n_args++;
 219   return 0;
 220 }
 221
 222 /* Create a dummy BFD.  */
 223 bfd *
 224 plugin_get_ir_dummy_bfd (const char *name, bfd *srctemplate)
 225 {
 226   asection *sec;
 227   bfd *abfd = bfd_create (
 228                 concat (name, IRONLY_SUFFIX, (const char *)NULL),
 229                 srctemplate);
 230   bfd_set_arch_info (abfd, bfd_get_arch_info (srctemplate));
 231   bfd_make_writable (abfd);
 232   /* Create a minimal set of sections to own the symbols.  */
 233   sec = bfd_make_section_old_way (abfd, ".text");
 234   bfd_set_section_flags (abfd, sec,
 235         SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
 236         | SEC_ALLOC | SEC_LOAD | SEC_KEEP);
 237   sec->output_section = sec;
 238   sec->output_offset = 0;
 239   return abfd;
 240 }
 241
 242 /* Check if the BFD is an IR dummy.  */
 243 bfd_boolean
 244 is_ir_dummy_bfd (const bfd *abfd)
 245 {
 246   size_t namlen = strlen (abfd->filename);
 247   if (namlen < IRONLY_SUFFIX_LEN)
 248     return FALSE;
 249   return !strcmp (abfd->filename + namlen - IRONLY_SUFFIX_LEN, IRONLY_SUFFIX);
 250 }
 251
 252 /* Helpers to convert between BFD and GOLD symbol formats.  */
 253 static enum ld_plugin_status
 254 asymbol_from_plugin_symbol (bfd *abfd, asymbol *asym,
 255                                 const struct ld_plugin_symbol *ldsym)
 256 {
 257   flagword flags = BSF_NO_FLAGS;
 258   struct bfd_section *section;
 259
 260   asym->the_bfd = abfd;
 261   asym->name = ldsym->version
 262                 ? concat (ldsym->name, "@", ldsym->version, NULL)
 263                 : ldsym->name;
 264   asym->value = 0;
 265   switch (ldsym->def)
 266     {
 267     case LDPK_WEAKDEF:
 268       flags = BSF_WEAK;
 269       /* FALLTHRU */
 270     case LDPK_DEF:
 271       flags |= BSF_GLOBAL;
 272       section = bfd_get_section_by_name (abfd, ".text");
 273       break;
 274
 275     case LDPK_WEAKUNDEF:
 276       flags = BSF_WEAK;
 277       /* FALLTHRU */
 278     case LDPK_UNDEF:
 279       section = bfd_und_section_ptr;
 280       break;
 281
 282     case LDPK_COMMON:
 283       flags = BSF_GLOBAL;
 284       section = bfd_com_section_ptr;
 285       asym->value = ldsym->size;
 286       break;
 287
 288     default:
 289       return LDPS_ERR;
 290     }
 291   asym->flags = flags;
 292   asym->section = section;
 293
 294   /* Visibility only applies on ELF targets.  */
 295   if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 296     {
 297       elf_symbol_type *elfsym = elf_symbol_from (abfd, asym);
 298       if (!elfsym)
 299         einfo (_("%P%F: %s: non-ELF symbol in ELF BFD!"), asym->name);
 300       elfsym->internal_elf_sym.st_other &= ~3;
 301       elfsym->internal_elf_sym.st_other |= ldsym->visibility;
 302     }
 303
 304   return LDPS_OK;
 305 }
 306
 307 /* Register a claim-file handler.  */
 308 static enum ld_plugin_status
 309 register_claim_file (ld_plugin_claim_file_handler handler)
 310 {
 311   ASSERT (called_plugin);
 312   called_plugin->claim_file_handler = handler;
 313   return LDPS_OK;
 314 }
 315
 316 /* Register an all-symbols-read handler.  */
 317 static enum ld_plugin_status
 318 register_all_symbols_read (ld_plugin_all_symbols_read_handler handler)
 319 {
 320   ASSERT (called_plugin);
 321   called_plugin->all_symbols_read_handler = handler;
 322   return LDPS_OK;
 323 }
 324
 325 /* Register a cleanup handler.  */
 326 static enum ld_plugin_status
 327 register_cleanup (ld_plugin_cleanup_handler handler)
 328 {
 329   ASSERT (called_plugin);
 330   called_plugin->cleanup_handler = handler;
 331   return LDPS_OK;
 332 }
 333
 334 /* Add symbols from a plugin-claimed input file.  */
 335 static enum ld_plugin_status
 336 add_symbols (void *handle, int nsyms, const struct ld_plugin_symbol *syms)
 337 {
 338   asymbol **symptrs;
 339   bfd *abfd = handle;
 340   int n;
 341   ASSERT (called_plugin);
 342   symptrs = xmalloc (nsyms * sizeof *symptrs);
 343   for (n = 0; n < nsyms; n++)
 344     {
 345       enum ld_plugin_status rv;
 346       asymbol *bfdsym = bfd_make_empty_symbol (abfd);
 347       symptrs[n] = bfdsym;
 348       rv = asymbol_from_plugin_symbol (abfd, bfdsym, syms + n);
 349       if (rv != LDPS_OK)
 350         return rv;
 351     }
 352   bfd_set_symtab (abfd, symptrs, nsyms);
 353   return LDPS_OK;
 354 }
 355
 356 /* Get the input file information with an open (possibly re-opened)
 357    file descriptor.  */
 358 static enum ld_plugin_status
 359 get_input_file (const void *handle, struct ld_plugin_input_file *file)
 360 {
 361   ASSERT (called_plugin);
 362   handle = handle;
 363   file = file;
 364   return LDPS_ERR;
 365 }
 366
 367 /* Release the input file.  */
 368 static enum ld_plugin_status
 369 release_input_file (const void *handle)
 370 {
 371   ASSERT (called_plugin);
 372   handle = handle;
 373   return LDPS_ERR;
 374 }
 375
 376 /* Get the symbol resolution info for a plugin-claimed input file.  */
 377 static enum ld_plugin_status
 378 get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
 379 {
 380   const bfd *abfd = handle;
 381   int n;
 382   ASSERT (called_plugin);
 383   for (n = 0; n < nsyms; n++)
 384     {
 385       struct bfd_link_hash_entry *blhe;
 386       bfd_boolean ironly;
 387
 388       blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
 389                                 FALSE, FALSE, TRUE);
 390       if (!blhe)
 391         {
 392           syms[n].resolution = LDPR_UNKNOWN;
 393           continue;
 394         }
 395
 396       /* Determine resolution from blhe type and symbol's original type.  */
 397       if (blhe->type == bfd_link_hash_undefined
 398                 || blhe->type == bfd_link_hash_undefweak)
 399         {
 400           syms[n].resolution = LDPR_UNDEF;
 401           continue;
 402         }
 403       if (blhe->type != bfd_link_hash_defined
 404                 && blhe->type != bfd_link_hash_defweak
 405                 && blhe->type != bfd_link_hash_common)
 406         {
 407           /* We should not have a new, indirect or warning symbol here.  */
 408           einfo ("%P%F: %s: plugin symbol table corrupt (sym type %d)",
 409                 called_plugin->name, blhe->type);
 410         }
 411
 412       /* We need to know if the sym is referenced from non-IR files.  */
 413       ironly = !bfd_hash_lookup (non_ironly_hash, syms[n].name, FALSE, FALSE);
 414
 415       /* If it was originally undefined or common, then it has been
 416          resolved; determine how.  */
 417       if (syms[n].def == LDPK_UNDEF || syms[n].def == LDPK_WEAKUNDEF
 418           || syms[n].def == LDPK_COMMON)
 419         {
 420           asection *owner_sec = (blhe->type == bfd_link_hash_common)
 421                                 ? blhe->u.c.p->section
 422                                 : blhe->u.def.section;
 423           if (owner_sec->owner == link_info.output_bfd)
 424             syms[n].resolution = LDPR_RESOLVED_EXEC;
 425           else if (owner_sec->owner == abfd)
 426             syms[n].resolution = (ironly)
 427                                 ? LDPR_PREVAILING_DEF_IRONLY
 428                                 : LDPR_PREVAILING_DEF;
 429           else if (is_ir_dummy_bfd (owner_sec->owner))
 430             syms[n].resolution = LDPR_RESOLVED_IR;
 431           else if (owner_sec->owner->flags & DYNAMIC)
 432             syms[n].resolution =  LDPR_RESOLVED_DYN;
 433           else
 434             syms[n].resolution = LDPR_RESOLVED_EXEC;
 435           continue;
 436         }
 437
 438       /* Was originally def, or weakdef.  Does it prevail?  If the
 439          owner is the original dummy bfd that supplied it, then this
 440          is the definition that has prevailed.  */
 441       if (blhe->u.def.section->owner == link_info.output_bfd)
 442         syms[n].resolution = LDPR_PREEMPTED_REG;
 443       else if (blhe->u.def.section->owner == abfd)
 444         {
 445           syms[n].resolution = (ironly)
 446                                 ? LDPR_PREVAILING_DEF_IRONLY
 447                                 : LDPR_PREVAILING_DEF;
 448           continue;
 449         }
 450
 451       /* Was originally def, weakdef, or common, but has been pre-empted.  */
 452       syms[n].resolution = is_ir_dummy_bfd (blhe->u.def.section->owner)
 453                                 ? LDPR_PREEMPTED_IR
 454                                 : LDPR_PREEMPTED_REG;
 455     }
 456   return LDPS_OK;
 457 }
 458
 459 /* Add a new (real) input file generated by a plugin.  */
 460 static enum ld_plugin_status
 461 add_input_file (const char *pathname)
 462 {
 463   ASSERT (called_plugin);
 464   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
 465         NULL))
 466     return LDPS_ERR;
 467   return LDPS_OK;
 468 }
 469
 470 /* Add a new (real) library required by a plugin.  */
 471 static enum ld_plugin_status
 472 add_input_library (const char *pathname)
 473 {
 474   ASSERT (called_plugin);
 475   if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
 476         NULL))
 477     return LDPS_ERR;
 478   return LDPS_OK;
 479 }
 480
 481 /* Set the extra library path to be used by libraries added via
 482    add_input_library.  */
 483 static enum ld_plugin_status
 484 set_extra_library_path (const char *path)
 485 {
 486   ASSERT (called_plugin);
 487   ldfile_add_library_path (xstrdup (path), FALSE);
 488   return LDPS_OK;
 489 }
 490
 491 /* Issue a diagnostic message from a plugin.  */
 492 static enum ld_plugin_status
 493 message (int level, const char *format, ...)
 494 {
 495   va_list args;
 496   va_start (args, format);
 497
 498   switch (level)
 499     {
 500     case LDPL_INFO:
 501       vfinfo (stdout, format, args, FALSE);
 502       break;
 503     case LDPL_WARNING:
 504       vfinfo (stdout, format, args, TRUE);
 505       break;
 506     case LDPL_FATAL:
 507     case LDPL_ERROR:
 508     default:
 509       {
 510         char *newfmt = ACONCAT ((level == LDPL_FATAL ? "%F" : "%X",
 511                                 format, NULL));
 512         vfinfo (stderr, newfmt, args, TRUE);
 513       }
 514       break;
 515     }
 516
 517   va_end (args);
 518   return LDPS_OK;
 519 }
 520
 521 /* Helper to size leading part of tv array and set it up. */
 522 static size_t
 523 set_tv_header (struct ld_plugin_tv *tv)
 524 {
 525   size_t i;
 526
 527   /* Version info.  */
 528   static const unsigned int major = (unsigned)(BFD_VERSION / 100000000UL);
 529   static const unsigned int minor = (unsigned)(BFD_VERSION / 1000000UL) % 100;
 530
 531   if (!tv)
 532     return tv_header_size;
 533
 534   for (i = 0; i < tv_header_size; i++)
 535     {
 536       tv[i].tv_tag = tv_header_tags[i];
 537 #define TVU(x) tv[i].tv_u.tv_ ## x
 538       switch (tv[i].tv_tag)
 539         {
 540           case LDPT_MESSAGE:
 541             TVU(message) = message;
 542             break;
 543           case LDPT_API_VERSION:
 544             TVU(val) = LD_PLUGIN_API_VERSION;
 545             break;
 546           case LDPT_GNU_LD_VERSION:
 547             TVU(val) = major * 100 + minor;
 548             break;
 549           case LDPT_LINKER_OUTPUT:
 550             TVU(val) = link_info.relocatable ? LDPO_REL
 551                         : (link_info.shared ? LDPO_DYN : LDPO_EXEC);
 552             break;
 553           case LDPT_OUTPUT_NAME:
 554             TVU(string) = output_filename;
 555             break;
 556           case LDPT_REGISTER_CLAIM_FILE_HOOK:
 557             TVU(register_claim_file) = register_claim_file;
 558             break;
 559           case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
 560             TVU(register_all_symbols_read) = register_all_symbols_read;
 561             break;
 562           case LDPT_REGISTER_CLEANUP_HOOK:
 563             TVU(register_cleanup) = register_cleanup;
 564             break;
 565           case LDPT_ADD_SYMBOLS:
 566             TVU(add_symbols) = add_symbols;
 567             break;
 568           case LDPT_GET_INPUT_FILE:
 569             TVU(get_input_file) = get_input_file;
 570             break;
 571           case LDPT_RELEASE_INPUT_FILE:
 572             TVU(release_input_file) = release_input_file;
 573             break;
 574           case LDPT_GET_SYMBOLS:
 575             TVU(get_symbols) = get_symbols;
 576             break;
 577           case LDPT_ADD_INPUT_FILE:
 578             TVU(add_input_file) = add_input_file;
 579             break;
 580           case LDPT_ADD_INPUT_LIBRARY:
 581             TVU(add_input_library) = add_input_library;
 582             break;
 583           case LDPT_SET_EXTRA_LIBRARY_PATH:
 584             TVU(set_extra_library_path) = set_extra_library_path;
 585             break;
 586           default:
 587             /* Added a new entry to the array without adding
 588                a new case to set up its value is a bug.  */
 589             FAIL ();
 590         }
 591 #undef TVU
 592     }
 593   return tv_header_size;
 594 }
 595
 596 /* Append the per-plugin args list and trailing LDPT_NULL to tv.  */
 597 static void
 598 set_tv_plugin_args (plugin_t *plugin, struct ld_plugin_tv *tv)
 599 {
 600   plugin_arg_t *arg = plugin->args;
 601   while (arg)
 602     {
 603       tv->tv_tag = LDPT_OPTION;
 604       tv->tv_u.tv_string = arg->arg;
 605       arg = arg->next;
 606       tv++;
 607     }
 608   tv->tv_tag = LDPT_NULL;
 609   tv->tv_u.tv_val = 0;
 610 }
 611
 612 /* Load up and initialise all plugins after argument parsing.  */
 613 int plugin_load_plugins (void)
 614 {
 615   struct ld_plugin_tv *my_tv;
 616   unsigned int max_args = 0;
 617   plugin_t *curplug = plugins_list;
 618
 619   /* If there are no plugins, we need do nothing this run.  */
 620   if (!curplug)
 621     return 0;
 622
 623   /* First pass over plugins to find max # args needed so that we
 624      can size and allocate the tv array.  */
 625   while (curplug)
 626     {
 627       if (curplug->n_args > max_args)
 628         max_args = curplug->n_args;
 629       curplug = curplug->next;
 630     }
 631
 632   /* Allocate tv array and initialise constant part.  */
 633   my_tv = xmalloc ((max_args + 1 + tv_header_size) * sizeof *my_tv);
 634   set_tv_header (my_tv);
 635
 636   /* Pass over plugins again, activating them.  */
 637   curplug = plugins_list;
 638   while (curplug)
 639     {
 640       enum ld_plugin_status rv;
 641       ld_plugin_onload onloadfn = dlsym (curplug->dlhandle, "onload");
 642       if (!onloadfn)
 643         onloadfn = dlsym (curplug->dlhandle, "_onload");
 644       if (!onloadfn)
 645         return set_plugin_error (curplug->name);
 646       set_tv_plugin_args (curplug, &my_tv[tv_header_size]);
 647       called_plugin = curplug;
 648       rv = (*onloadfn) (my_tv);
 649       called_plugin = NULL;
 650       if (rv != LDPS_OK)
 651         return set_plugin_error (curplug->name);
 652       curplug = curplug->next;
 653     }
 654
 655   /* Since plugin(s) inited ok, assume they're going to want symbol
 656      resolutions, which needs us to track which symbols are referenced
 657      by non-IR files using the linker's notice callback.  */
 658   link_info.notice_all = TRUE;
 659
 660   return 0;
 661 }
 662
 663 /* Call 'claim file' hook for all plugins.  */
 664 int
 665 plugin_call_claim_file (const struct ld_plugin_input_file *file, int *claimed)
 666 {
 667   plugin_t *curplug = plugins_list;
 668   *claimed = FALSE;
 669   if (no_more_claiming)
 670     return 0;
 671   while (curplug && !*claimed)
 672     {
 673       if (curplug->claim_file_handler)
 674         {
 675           enum ld_plugin_status rv;
 676           called_plugin = curplug;
 677           rv = (*curplug->claim_file_handler) (file, claimed);
 678           called_plugin = NULL;
 679           if (rv != LDPS_OK)
 680             set_plugin_error (curplug->name);
 681         }
 682       curplug = curplug->next;
 683     }
 684   return plugin_error_p () ? -1 : 0;
 685 }
 686
 687 /* Call 'all symbols read' hook for all plugins.  */
 688 int
 689 plugin_call_all_symbols_read (void)
 690 {
 691   plugin_t *curplug = plugins_list;
 692
 693   /* Disable any further file-claiming.  */
 694   no_more_claiming = TRUE;
 695
 696   /* If --allow-multiple-definition is in effect, we need to disable it,
 697      as the plugin infrastructure relies on the multiple_definition
 698      callback to swap out the dummy IR-only BFDs for new real ones
 699      when it starts opening the files added during this callback.  */
 700   plugin_cached_allow_multiple_defs = link_info.allow_multiple_definition;
 701   link_info.allow_multiple_definition = FALSE;
 702
 703   while (curplug)
 704     {
 705       if (curplug->all_symbols_read_handler)
 706         {
 707           enum ld_plugin_status rv;
 708           called_plugin = curplug;
 709           rv = (*curplug->all_symbols_read_handler) ();
 710           called_plugin = NULL;
 711           if (rv != LDPS_OK)
 712             set_plugin_error (curplug->name);
 713         }
 714       curplug = curplug->next;
 715     }
 716   return plugin_error_p () ? -1 : 0;
 717 }
 718
 719 /* Call 'cleanup' hook for all plugins.  */
 720 int
 721 plugin_call_cleanup (void)
 722 {
 723   plugin_t *curplug = plugins_list;
 724   while (curplug)
 725     {
 726       if (curplug->cleanup_handler && !curplug->cleanup_done)
 727         {
 728           enum ld_plugin_status rv;
 729           curplug->cleanup_done = TRUE;
 730           called_plugin = curplug;
 731           rv = (*curplug->cleanup_handler) ();
 732           called_plugin = NULL;
 733           if (rv != LDPS_OK)
 734             set_plugin_error (curplug->name);
 735           dlclose (curplug->dlhandle);
 736         }
 737       curplug = curplug->next;
 738     }
 739   return plugin_error_p () ? -1 : 0;
 740 }
 741
 742 /* Lazily init the non_ironly hash table.  */
 743 static void
 744 init_non_ironly_hash (void)
 745 {
 746   if (non_ironly_hash == NULL)
 747     {
 748       non_ironly_hash =
 749           (struct bfd_hash_table *) xmalloc (sizeof (struct bfd_hash_table));
 750       if (!bfd_hash_table_init_n (non_ironly_hash,
 751                                   bfd_hash_newfunc,
 752                                   sizeof (struct bfd_hash_entry),
 753                                   61))
 754         einfo (_("%P%F: bfd_hash_table_init failed: %E\n"));
 755     }
 756 }
 757
 758 /* To determine which symbols should be resolved LDPR_PREVAILING_DEF
 759    and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
 760    the linker adds them to the linker hash table.  If we see a symbol
 761    being referenced from a non-IR file, we add it to the non_ironly hash
 762    table.  If we can't find it there at get_symbols time, we know that
 763    it was referenced only by IR files.  We have to notice_all symbols,
 764    because we won't necessarily know until later which ones will be
 765    contributed by IR files.  */
 766 bfd_boolean
 767 plugin_notice (struct bfd_link_info *info ATTRIBUTE_UNUSED,
 768                 const char *name, bfd *abfd,
 769                 asection *section, bfd_vma value ATTRIBUTE_UNUSED)
 770 {
 771   bfd_boolean is_ref = bfd_is_und_section (section);
 772   bfd_boolean is_dummy = is_ir_dummy_bfd (abfd);
 773   init_non_ironly_hash ();
 774   /* We only care about refs, not defs, indicated by section pointing
 775      to the undefined section (according to the bfd linker notice callback
 776      interface definition).  */
 777   if (is_ref && !is_dummy)
 778     {
 779       /* This is a ref from a non-IR file, so note the ref'd symbol
 780          in the non-IR-only hash.  */
 781       if (!bfd_hash_lookup (non_ironly_hash, name, TRUE, TRUE))
 782         einfo (_("%P%X: %s: hash table failure adding symbol %s"),
 783                 abfd->filename, name);
 784     }
 785   else if (!is_ref && is_dummy)
 786     {
 787       /* No further processing since this is a def from an IR dummy BFD.  */
 788       return FALSE;
 789     }
 790
 791   /* Continue with cref/nocrossref/trace-sym processing.  */
 792   return TRUE;
 793 }
 794
 795 /* When we add new object files to the link at all symbols read time,
 796    these contain the real code and symbols generated from the IR files,
 797    and so duplicate all the definitions already supplied by the dummy
 798    IR-only BFDs that we created at claim files time.  We use the linker's
 799    multiple-definitions callback hook to fix up the clash, discarding
 800    the symbol from the IR-only BFD in favour of the symbol from the
 801    real BFD.  We return true if this was not-really-a-clash because
 802    we've fixed it up, or anyway if --allow-multiple-definition was in
 803    effect (before we disabled it to ensure we got called back).  */
 804 bfd_boolean
 805 plugin_multiple_definition (struct bfd_link_info *info, const char *name,
 806                 bfd *obfd, asection *osec ATTRIBUTE_UNUSED,
 807                 bfd_vma oval ATTRIBUTE_UNUSED,
 808                 bfd *nbfd, asection *nsec, bfd_vma nval)
 809 {
 810   if (is_ir_dummy_bfd (obfd))
 811     {
 812       struct bfd_link_hash_entry *blhe = bfd_link_hash_lookup (info->hash,
 813                                         name, FALSE, FALSE, FALSE);
 814       if (!blhe)
 815         einfo (_("%P%X: %s: can't find IR symbol '%s'"), nbfd->filename,
 816                 name);
 817       else if (blhe->type != bfd_link_hash_defined)
 818         einfo (_("%P%x: %s: bad IR symbol type %d"), name, blhe->type);
 819       /* Replace it with new details.  */
 820       blhe->u.def.section = nsec;
 821       blhe->u.def.value = nval;
 822       return TRUE;
 823     }
 824   return plugin_cached_allow_multiple_defs;
 825 }