ld/emultempl/ppc64elf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   3 #
   4 # This file is part of GLD, the Gnu Linker.
   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 2 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, MA 02110-1301, USA.
  19 #
  20
  21 # This file is sourced from elf32.em, and defines extra powerpc64-elf
  22 # specific routines.
  23 #
  24 cat >>e${EMULATION_NAME}.c <<EOF
  25
  26 #include "ldctor.h"
  27 #include "libbfd.h"
  28 #include "elf-bfd.h"
  29 #include "elf64-ppc.h"
  30
  31 /* Fake input file for stubs.  */
  32 static lang_input_statement_type *stub_file;
  33 static int stub_added = 0;
  34
  35 /* Whether we need to call ppc_layout_sections_again.  */
  36 static int need_laying_out = 0;
  37
  38 /* Maximum size of a group of input sections that can be handled by
  39    one stub section.  A value of +/-1 indicates the bfd back-end
  40    should use a suitable default size.  */
  41 static bfd_signed_vma group_size = 1;
  42
  43 /* Whether to add ".foo" entries for each "foo" in a version script.  */
  44 static int dotsyms = 1;
  45
  46 /* Whether to run tls optimization.  */
  47 static int no_tls_opt = 0;
  48
  49 /* Whether to run opd optimization.  */
  50 static int no_opd_opt = 0;
  51
  52 /* Whether to run toc optimization.  */
  53 static int no_toc_opt = 0;
  54
  55 /* Whether to allow multiple toc sections.  */
  56 static int no_multi_toc = 0;
  57
  58 /* Whether to emit symbols for stubs.  */
  59 static int emit_stub_syms = 0;
  60
  61 static asection *toc_section = 0;
  62
  63 /* Whether to canonicalize .opd so that there are no overlapping
  64    .opd entries.  */
  65 static int non_overlapping_opd = 0;
  66
  67 /* This is called before the input files are opened.  We create a new
  68    fake input file to hold the stub sections.  */
  69
  70 static void
  71 ppc_create_output_section_statements (void)
  72 {
  73   extern const bfd_target bfd_elf64_powerpc_vec;
  74   extern const bfd_target bfd_elf64_powerpcle_vec;
  75
  76   if (link_info.hash->creator != &bfd_elf64_powerpc_vec
  77       && link_info.hash->creator != &bfd_elf64_powerpcle_vec)
  78     return;
  79
  80   link_info.wrap_char = '.';
  81
  82   stub_file = lang_add_input_file ("linker stubs",
  83                                    lang_input_file_is_fake_enum,
  84                                    NULL);
  85   stub_file->the_bfd = bfd_create ("linker stubs", output_bfd);
  86   if (stub_file->the_bfd == NULL
  87       || !bfd_set_arch_mach (stub_file->the_bfd,
  88                              bfd_get_arch (output_bfd),
  89                              bfd_get_mach (output_bfd)))
  90     {
  91       einfo ("%F%P: can not create BFD %E\n");
  92       return;
  93     }
  94
  95   stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
  96   ldlang_add_file (stub_file);
  97   ppc64_elf_init_stub_bfd (stub_file->the_bfd, &link_info);
  98 }
  99
 100 static void
 101 ppc_before_allocation (void)
 102 {
 103   if (stub_file != NULL)
 104     {
 105       if (!ppc64_elf_edit_opd (output_bfd, &link_info, no_opd_opt,
 106                                non_overlapping_opd))
 107         einfo ("%X%P: can not edit %s %E\n", "opd");
 108
 109       if (ppc64_elf_tls_setup (output_bfd, &link_info) && !no_tls_opt)
 110         {
 111           /* Size the sections.  This is premature, but we want to know the
 112              TLS segment layout so that certain optimizations can be done.  */
 113           expld.phase = lang_mark_phase_enum;
 114           expld.dataseg.phase = exp_dataseg_none;
 115           one_lang_size_sections_pass (NULL, TRUE);
 116
 117           if (!ppc64_elf_tls_optimize (output_bfd, &link_info))
 118             einfo ("%X%P: TLS problem %E\n");
 119
 120           /* We must not cache anything from the preliminary sizing.  */
 121           lang_reset_memory_regions ();
 122         }
 123
 124       if (!no_toc_opt
 125           && !link_info.relocatable
 126           && !ppc64_elf_edit_toc (output_bfd, &link_info))
 127         einfo ("%X%P: can not edit %s %E\n", "toc");
 128     }
 129
 130   gld${EMULATION_NAME}_before_allocation ();
 131 }
 132
 133 struct hook_stub_info
 134 {
 135   lang_statement_list_type add;
 136   asection *input_section;
 137 };
 138
 139 /* Traverse the linker tree to find the spot where the stub goes.  */
 140
 141 static bfd_boolean
 142 hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp)
 143 {
 144   lang_statement_union_type *l;
 145   bfd_boolean ret;
 146
 147   for (; (l = *lp) != NULL; lp = &l->header.next)
 148     {
 149       switch (l->header.type)
 150         {
 151         case lang_constructors_statement_enum:
 152           ret = hook_in_stub (info, &constructor_list.head);
 153           if (ret)
 154             return ret;
 155           break;
 156
 157         case lang_output_section_statement_enum:
 158           ret = hook_in_stub (info,
 159                               &l->output_section_statement.children.head);
 160           if (ret)
 161             return ret;
 162           break;
 163
 164         case lang_wild_statement_enum:
 165           ret = hook_in_stub (info, &l->wild_statement.children.head);
 166           if (ret)
 167             return ret;
 168           break;
 169
 170         case lang_group_statement_enum:
 171           ret = hook_in_stub (info, &l->group_statement.children.head);
 172           if (ret)
 173             return ret;
 174           break;
 175
 176         case lang_input_section_enum:
 177           if (l->input_section.section == info->input_section)
 178             {
 179               /* We've found our section.  Insert the stub immediately
 180                  before its associated input section.  */
 181               *lp = info->add.head;
 182               *(info->add.tail) = l;
 183               return TRUE;
 184             }
 185           break;
 186
 187         case lang_data_statement_enum:
 188         case lang_reloc_statement_enum:
 189         case lang_object_symbols_statement_enum:
 190         case lang_output_statement_enum:
 191         case lang_target_statement_enum:
 192         case lang_input_statement_enum:
 193         case lang_assignment_statement_enum:
 194         case lang_padding_statement_enum:
 195         case lang_address_statement_enum:
 196         case lang_fill_statement_enum:
 197           break;
 198
 199         default:
 200           FAIL ();
 201           break;
 202         }
 203     }
 204   return FALSE;
 205 }
 206
 207
 208 /* Call-back for ppc64_elf_size_stubs.  */
 209
 210 /* Create a new stub section, and arrange for it to be linked
 211    immediately before INPUT_SECTION.  */
 212
 213 static asection *
 214 ppc_add_stub_section (const char *stub_sec_name, asection *input_section)
 215 {
 216   asection *stub_sec;
 217   flagword flags;
 218   asection *output_section;
 219   const char *secname;
 220   lang_output_section_statement_type *os;
 221   struct hook_stub_info info;
 222
 223   stub_sec = bfd_make_section_anyway (stub_file->the_bfd, stub_sec_name);
 224   if (stub_sec == NULL)
 225     goto err_ret;
 226
 227   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 228            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 229   if (!bfd_set_section_flags (stub_file->the_bfd, stub_sec, flags))
 230     goto err_ret;
 231
 232   output_section = input_section->output_section;
 233   secname = bfd_get_section_name (output_section->owner, output_section);
 234   os = lang_output_section_find (secname);
 235
 236   info.input_section = input_section;
 237   lang_list_init (&info.add);
 238   lang_add_section (&info.add, stub_sec, os);
 239
 240   if (info.add.head == NULL)
 241     goto err_ret;
 242
 243   stub_added = 1;
 244   if (hook_in_stub (&info, &os->children.head))
 245     return stub_sec;
 246
 247  err_ret:
 248   einfo ("%X%P: can not make stub section: %E\n");
 249   return NULL;
 250 }
 251
 252
 253 /* Another call-back for ppc64_elf_size_stubs.  */
 254
 255 static void
 256 ppc_layout_sections_again (void)
 257 {
 258   /* If we have changed sizes of the stub sections, then we need
 259      to recalculate all the section offsets.  This may mean we need to
 260      add even more stubs.  */
 261   gld${EMULATION_NAME}_map_segments (TRUE);
 262   need_laying_out = -1;
 263 }
 264
 265
 266 /* Call the back-end function to set TOC base after we have placed all
 267    the sections.  */
 268 static void
 269 gld${EMULATION_NAME}_after_allocation (void)
 270 {
 271   if (!link_info.relocatable)
 272     _bfd_set_gp_value (output_bfd, ppc64_elf_toc (output_bfd));
 273 }
 274
 275
 276 static void
 277 build_toc_list (lang_statement_union_type *statement)
 278 {
 279   if (statement->header.type == lang_input_section_enum)
 280     {
 281       asection *i = statement->input_section.section;
 282
 283       if (!((lang_input_statement_type *) i->owner->usrdata)->just_syms_flag
 284           && (i->flags & SEC_EXCLUDE) == 0
 285           && i->output_section == toc_section)
 286         ppc64_elf_next_toc_section (&link_info, i);
 287     }
 288 }
 289
 290
 291 static void
 292 build_section_lists (lang_statement_union_type *statement)
 293 {
 294   if (statement->header.type == lang_input_section_enum)
 295     {
 296       asection *i = statement->input_section.section;
 297
 298       if (!((lang_input_statement_type *) i->owner->usrdata)->just_syms_flag
 299           && (i->flags & SEC_EXCLUDE) == 0
 300           && i->output_section != NULL
 301           && i->output_section->owner == output_bfd)
 302         {
 303           if (!ppc64_elf_next_input_section (&link_info, i))
 304             einfo ("%X%P: can not size stub section: %E\n");
 305         }
 306     }
 307 }
 308
 309
 310 /* Final emulation specific call.  */
 311
 312 static void
 313 gld${EMULATION_NAME}_finish (void)
 314 {
 315   /* e_entry on PowerPC64 points to the function descriptor for
 316      _start.  If _start is missing, default to the first function
 317      descriptor in the .opd section.  */
 318   entry_section = ".opd";
 319
 320   /* bfd_elf_discard_info just plays with debugging sections,
 321      ie. doesn't affect any code, so we can delay resizing the
 322      sections.  It's likely we'll resize everything in the process of
 323      adding stubs.  */
 324   if (bfd_elf_discard_info (output_bfd, &link_info))
 325     need_laying_out = 1;
 326
 327   /* If generating a relocatable output file, then we don't have any
 328      stubs.  */
 329   if (stub_file != NULL && !link_info.relocatable)
 330     {
 331       int ret = ppc64_elf_setup_section_lists (output_bfd, &link_info,
 332                                                no_multi_toc);
 333       if (ret < 0)
 334         einfo ("%X%P: can not size stub section: %E\n");
 335       else if (ret > 0)
 336         {
 337           toc_section = bfd_get_section_by_name (output_bfd, ".got");
 338           if (toc_section != NULL)
 339             lang_for_each_statement (build_toc_list);
 340
 341           ppc64_elf_reinit_toc (output_bfd, &link_info);
 342
 343           lang_for_each_statement (build_section_lists);
 344
 345           /* Call into the BFD backend to do the real work.  */
 346           if (!ppc64_elf_size_stubs (output_bfd,
 347                                      &link_info,
 348                                      group_size,
 349                                      &ppc_add_stub_section,
 350                                      &ppc_layout_sections_again))
 351             einfo ("%X%P: can not size stub section: %E\n");
 352         }
 353     }
 354
 355   if (need_laying_out != -1)
 356     gld${EMULATION_NAME}_map_segments (need_laying_out);
 357
 358   if (link_info.relocatable)
 359     {
 360       asection *toc = bfd_get_section_by_name (output_bfd, ".toc");
 361       if (toc != NULL
 362           && bfd_section_size (output_bfd, toc) > 0x10000)
 363         einfo ("%X%P: TOC section size exceeds 64k\n");
 364     }
 365
 366   if (stub_added)
 367     {
 368       char *msg = NULL;
 369       char *line, *endline;
 370
 371       emit_stub_syms |= link_info.emitrelocations;
 372       if (!ppc64_elf_build_stubs (emit_stub_syms, &link_info,
 373                                   config.stats ? &msg : NULL))
 374         einfo ("%X%P: can not build stubs: %E\n");
 375
 376       for (line = msg; line != NULL; line = endline)
 377         {
 378           endline = strchr (line, '\n');
 379           if (endline != NULL)
 380             *endline++ = '\0';
 381           fprintf (stderr, "%s: %s\n", program_name, line);
 382         }
 383       if (msg != NULL)
 384         free (msg);
 385     }
 386
 387   ppc64_elf_restore_symbols (&link_info);
 388   finish_default ();
 389 }
 390
 391
 392 /* Add a pattern matching ".foo" for every "foo" in a version script.
 393
 394    The reason for doing this is that many shared library version
 395    scripts export a selected set of functions or data symbols, forcing
 396    others local.  eg.
 397
 398    . VERS_1 {
 399    .       global:
 400    .               this; that; some; thing;
 401    .       local:
 402    .               *;
 403    .   };
 404
 405    To make the above work for PowerPC64, we need to export ".this",
 406    ".that" and so on, otherwise only the function descriptor syms are
 407    exported.  Lack of an exported function code sym may cause a
 408    definition to be pulled in from a static library.  */
 409
 410 static struct bfd_elf_version_expr *
 411 gld${EMULATION_NAME}_new_vers_pattern (struct bfd_elf_version_expr *entry)
 412 {
 413   struct bfd_elf_version_expr *dot_entry;
 414   unsigned int len;
 415   char *dot_pat;
 416
 417   if (!dotsyms || entry->pattern[0] == '*' || entry->pattern[0] == '.')
 418     return entry;
 419
 420   dot_entry = xmalloc (sizeof *dot_entry);
 421   *dot_entry = *entry;
 422   dot_entry->next = entry;
 423   len = strlen (entry->pattern) + 2;
 424   dot_pat = xmalloc (len);
 425   dot_pat[0] = '.';
 426   memcpy (dot_pat + 1, entry->pattern, len - 1);
 427   dot_entry->pattern = dot_pat;
 428   if (entry->symbol != NULL)
 429     {
 430       len = strlen (entry->symbol) + 2;
 431       dot_pat = xmalloc (len);
 432       dot_pat[0] = '.';
 433       memcpy (dot_pat + 1, entry->symbol, len - 1);
 434       dot_entry->symbol = dot_pat;
 435     }
 436   return dot_entry;
 437 }
 438
 439
 440 /* Avoid processing the fake stub_file in vercheck, stat_needed and
 441    check_needed routines.  */
 442
 443 static void (*real_func) (lang_input_statement_type *);
 444
 445 static void ppc_for_each_input_file_wrapper (lang_input_statement_type *l)
 446 {
 447   if (l != stub_file)
 448     (*real_func) (l);
 449 }
 450
 451 static void
 452 ppc_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
 453 {
 454   real_func = func;
 455   lang_for_each_input_file (&ppc_for_each_input_file_wrapper);
 456 }
 457
 458 #define lang_for_each_input_file ppc_lang_for_each_input_file
 459
 460 EOF
 461
 462 # Define some shell vars to insert bits of code into the standard elf
 463 # parse_args and list_options functions.
 464 #
 465 PARSE_AND_LIST_PROLOGUE='
 466 #define OPTION_STUBGROUP_SIZE           301
 467 #define OPTION_STUBSYMS                 (OPTION_STUBGROUP_SIZE + 1)
 468 #define OPTION_DOTSYMS                  (OPTION_STUBSYMS + 1)
 469 #define OPTION_NO_DOTSYMS               (OPTION_DOTSYMS + 1)
 470 #define OPTION_NO_TLS_OPT               (OPTION_NO_DOTSYMS + 1)
 471 #define OPTION_NO_OPD_OPT               (OPTION_NO_TLS_OPT + 1)
 472 #define OPTION_NO_TOC_OPT               (OPTION_NO_OPD_OPT + 1)
 473 #define OPTION_NO_MULTI_TOC             (OPTION_NO_TOC_OPT + 1)
 474 #define OPTION_NON_OVERLAPPING_OPD      (OPTION_NO_MULTI_TOC + 1)
 475 '
 476
 477 PARSE_AND_LIST_LONGOPTS='
 478   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 479   { "emit-stub-syms", no_argument, NULL, OPTION_STUBSYMS },
 480   { "dotsyms", no_argument, NULL, OPTION_DOTSYMS },
 481   { "no-dotsyms", no_argument, NULL, OPTION_NO_DOTSYMS },
 482   { "no-tls-optimize", no_argument, NULL, OPTION_NO_TLS_OPT },
 483   { "no-opd-optimize", no_argument, NULL, OPTION_NO_OPD_OPT },
 484   { "no-toc-optimize", no_argument, NULL, OPTION_NO_TOC_OPT },
 485   { "no-multi-toc", no_argument, NULL, OPTION_NO_MULTI_TOC },
 486   { "non-overlapping-opd", no_argument, NULL, OPTION_NON_OVERLAPPING_OPD },
 487 '
 488
 489 PARSE_AND_LIST_OPTIONS='
 490   fprintf (file, _("\
 491   --stub-group-size=N   Maximum size of a group of input sections that can be\n\
 492                           handled by one stub section.  A negative value\n\
 493                           locates all stubs before their branches (with a\n\
 494                           group size of -N), while a positive value allows\n\
 495                           two groups of input sections, one before, and one\n\
 496                           after each stub section.  Values of +/-1 indicate\n\
 497                           the linker should choose suitable defaults.\n"
 498                    ));
 499   fprintf (file, _("\
 500   --emit-stub-syms      Label linker stubs with a symbol.\n"
 501                    ));
 502   fprintf (file, _("\
 503   --dotsyms             For every version pattern \"foo\" in a version script,\n\
 504                           add \".foo\" so that function code symbols are\n\
 505                           treated the same as function descriptor symbols.\n\
 506                           Defaults to on.\n"
 507                    ));
 508   fprintf (file, _("\
 509   --no-dotsyms          Don'\''t do anything special in version scripts.\n"
 510                    ));
 511   fprintf (file, _("\
 512   --no-tls-optimize     Don'\''t try to optimize TLS accesses.\n"
 513                    ));
 514   fprintf (file, _("\
 515   --no-opd-optimize     Don'\''t optimize the OPD section.\n"
 516                    ));
 517   fprintf (file, _("\
 518   --no-toc-optimize     Don'\''t optimize the TOC section.\n"
 519                    ));
 520   fprintf (file, _("\
 521   --no-multi-toc        Disallow automatic multiple toc sections.\n"
 522                    ));
 523   fprintf (file, _("\
 524   --non-overlapping-opd Canonicalize .opd, so that there are no overlapping\n\
 525                           .opd entries.\n"
 526                    ));
 527 '
 528
 529 PARSE_AND_LIST_ARGS_CASES='
 530     case OPTION_STUBGROUP_SIZE:
 531       {
 532         const char *end;
 533         group_size = bfd_scan_vma (optarg, &end, 0);
 534         if (*end)
 535           einfo (_("%P%F: invalid number `%s'\''\n"), optarg);
 536       }
 537       break;
 538
 539     case OPTION_STUBSYMS:
 540       emit_stub_syms = 1;
 541       break;
 542
 543     case OPTION_DOTSYMS:
 544       dotsyms = 1;
 545       break;
 546
 547     case OPTION_NO_DOTSYMS:
 548       dotsyms = 0;
 549       break;
 550
 551     case OPTION_NO_TLS_OPT:
 552       no_tls_opt = 1;
 553       break;
 554
 555     case OPTION_NO_OPD_OPT:
 556       no_opd_opt = 1;
 557       break;
 558
 559     case OPTION_NO_TOC_OPT:
 560       no_toc_opt = 1;
 561       break;
 562
 563     case OPTION_NO_MULTI_TOC:
 564       no_multi_toc = 1;
 565       break;
 566
 567     case OPTION_NON_OVERLAPPING_OPD:
 568       non_overlapping_opd = 1;
 569       break;
 570 '
 571
 572 # Put these extra ppc64elf routines in ld_${EMULATION_NAME}_emulation
 573 #
 574 LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
 575 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 576 LDEMUL_FINISH=gld${EMULATION_NAME}_finish
 577 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_create_output_section_statements
 578 LDEMUL_NEW_VERS_PATTERN=gld${EMULATION_NAME}_new_vers_pattern