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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 (!no_opd_opt
 106           && !ppc64_elf_edit_opd (output_bfd, &link_info, 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           lang_size_sections (stat_ptr->head, abs_output_section,
 114                               &stat_ptr->head, 0, 0, NULL, TRUE);
 115
 116           if (!ppc64_elf_tls_optimize (output_bfd, &link_info))
 117             einfo ("%X%P: TLS problem %E\n");
 118
 119           /* We must not cache anything from the preliminary sizing.  */
 120           elf_tdata (output_bfd)->program_header_size = 0;
 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, stub_file);
 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   need_laying_out = 0;
 262
 263   lang_reset_memory_regions ();
 264
 265   /* Resize the sections.  */
 266   lang_size_sections (stat_ptr->head, abs_output_section,
 267                       &stat_ptr->head, 0, 0, NULL, TRUE);
 268
 269   /* Recalculate TOC base.  */
 270   ldemul_after_allocation ();
 271
 272   /* Do the assignments again.  */
 273   lang_do_assignments (stat_ptr->head, abs_output_section, NULL, 0);
 274 }
 275
 276
 277 /* Call the back-end function to set TOC base after we have placed all
 278    the sections.  */
 279 static void
 280 gld${EMULATION_NAME}_after_allocation (void)
 281 {
 282   if (!link_info.relocatable)
 283     _bfd_set_gp_value (output_bfd, ppc64_elf_toc (output_bfd));
 284 }
 285
 286
 287 static void
 288 build_toc_list (lang_statement_union_type *statement)
 289 {
 290   if (statement->header.type == lang_input_section_enum
 291       && !statement->input_section.ifile->just_syms_flag
 292       && (statement->input_section.section->flags & SEC_EXCLUDE) == 0
 293       && statement->input_section.section->output_section == toc_section)
 294     ppc64_elf_next_toc_section (&link_info, statement->input_section.section);
 295 }
 296
 297
 298 static void
 299 build_section_lists (lang_statement_union_type *statement)
 300 {
 301   if (statement->header.type == lang_input_section_enum
 302       && !statement->input_section.ifile->just_syms_flag
 303       && (statement->input_section.section->flags & SEC_EXCLUDE) == 0
 304       && statement->input_section.section->output_section != NULL
 305       && statement->input_section.section->output_section->owner == output_bfd)
 306     {
 307       if (!ppc64_elf_next_input_section (&link_info,
 308                                          statement->input_section.section))
 309         einfo ("%X%P: can not size stub section: %E\n");
 310     }
 311 }
 312
 313
 314 /* Final emulation specific call.  */
 315
 316 static void
 317 ppc_finish (void)
 318 {
 319   /* e_entry on PowerPC64 points to the function descriptor for
 320      _start.  If _start is missing, default to the first function
 321      descriptor in the .opd section.  */
 322   entry_section = ".opd";
 323
 324   /* bfd_elf_discard_info just plays with debugging sections,
 325      ie. doesn't affect any code, so we can delay resizing the
 326      sections.  It's likely we'll resize everything in the process of
 327      adding stubs.  */
 328   if (bfd_elf_discard_info (output_bfd, &link_info))
 329     need_laying_out = 1;
 330
 331   /* If generating a relocatable output file, then we don't have any
 332      stubs.  */
 333   if (stub_file != NULL && !link_info.relocatable)
 334     {
 335       int ret = ppc64_elf_setup_section_lists (output_bfd, &link_info,
 336                                                no_multi_toc);
 337       if (ret < 0)
 338         einfo ("%X%P: can not size stub section: %E\n");
 339       else if (ret > 0)
 340         {
 341           toc_section = bfd_get_section_by_name (output_bfd, ".got");
 342           if (toc_section != NULL)
 343             lang_for_each_statement (build_toc_list);
 344
 345           ppc64_elf_reinit_toc (output_bfd, &link_info);
 346
 347           lang_for_each_statement (build_section_lists);
 348
 349           /* Call into the BFD backend to do the real work.  */
 350           if (!ppc64_elf_size_stubs (output_bfd,
 351                                      &link_info,
 352                                      group_size,
 353                                      &ppc_add_stub_section,
 354                                      &ppc_layout_sections_again))
 355             einfo ("%X%P: can not size stub section: %E\n");
 356         }
 357     }
 358
 359   if (need_laying_out)
 360     ppc_layout_sections_again ();
 361
 362   if (link_info.relocatable)
 363     {
 364       asection *toc = bfd_get_section_by_name (output_bfd, ".toc");
 365       if (toc != NULL
 366           && bfd_section_size (output_bfd, toc) > 0x10000)
 367         einfo ("%X%P: TOC section size exceeds 64k\n");
 368     }
 369
 370   if (stub_added)
 371     {
 372       char *msg = NULL;
 373       char *line, *endline;
 374
 375       emit_stub_syms |= link_info.emitrelocations;
 376       if (!ppc64_elf_build_stubs (emit_stub_syms, &link_info,
 377                                   config.stats ? &msg : NULL))
 378         einfo ("%X%P: can not build stubs: %E\n");
 379
 380       for (line = msg; line != NULL; line = endline)
 381         {
 382           endline = strchr (line, '\n');
 383           if (endline != NULL)
 384             *endline++ = '\0';
 385           fprintf (stderr, "%s: %s\n", program_name, line);
 386         }
 387       if (msg != NULL)
 388         free (msg);
 389     }
 390
 391   ppc64_elf_restore_symbols (&link_info);
 392   gld${EMULATION_NAME}_finish ();
 393 }
 394
 395
 396 /* Add a pattern matching ".foo" for every "foo" in a version script.
 397
 398    The reason for doing this is that many shared library version
 399    scripts export a selected set of functions or data symbols, forcing
 400    others local.  eg.
 401
 402    . VERS_1 {
 403    .       global:
 404    .               this; that; some; thing;
 405    .       local:
 406    .               *;
 407    .   };
 408
 409    To make the above work for PowerPC64, we need to export ".this",
 410    ".that" and so on, otherwise only the function descriptor syms are
 411    exported.  Lack of an exported function code sym may cause a
 412    definition to be pulled in from a static library.  */
 413
 414 static struct bfd_elf_version_expr *
 415 gld${EMULATION_NAME}_new_vers_pattern (struct bfd_elf_version_expr *entry)
 416 {
 417   struct bfd_elf_version_expr *dot_entry;
 418   unsigned int len;
 419   char *dot_pat;
 420
 421   if (!dotsyms || entry->pattern[0] == '*' || entry->pattern[0] == '.')
 422     return entry;
 423
 424   dot_entry = xmalloc (sizeof *dot_entry);
 425   *dot_entry = *entry;
 426   dot_entry->next = entry;
 427   len = strlen (entry->pattern) + 2;
 428   dot_pat = xmalloc (len);
 429   dot_pat[0] = '.';
 430   memcpy (dot_pat + 1, entry->pattern, len - 1);
 431   dot_entry->pattern = dot_pat;
 432   if (entry->symbol != NULL)
 433     {
 434       len = strlen (entry->symbol) + 2;
 435       dot_pat = xmalloc (len);
 436       dot_pat[0] = '.';
 437       memcpy (dot_pat + 1, entry->symbol, len - 1);
 438       dot_entry->symbol = dot_pat;
 439     }
 440   return dot_entry;
 441 }
 442
 443
 444 /* Avoid processing the fake stub_file in vercheck, stat_needed and
 445    check_needed routines.  */
 446
 447 static void (*real_func) (lang_input_statement_type *);
 448
 449 static void ppc_for_each_input_file_wrapper (lang_input_statement_type *l)
 450 {
 451   if (l != stub_file)
 452     (*real_func) (l);
 453 }
 454
 455 static void
 456 ppc_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
 457 {
 458   real_func = func;
 459   lang_for_each_input_file (&ppc_for_each_input_file_wrapper);
 460 }
 461
 462 #define lang_for_each_input_file ppc_lang_for_each_input_file
 463
 464 EOF
 465
 466 # Define some shell vars to insert bits of code into the standard elf
 467 # parse_args and list_options functions.
 468 #
 469 PARSE_AND_LIST_PROLOGUE='
 470 #define OPTION_STUBGROUP_SIZE           301
 471 #define OPTION_STUBSYMS                 (OPTION_STUBGROUP_SIZE + 1)
 472 #define OPTION_DOTSYMS                  (OPTION_STUBSYMS + 1)
 473 #define OPTION_NO_DOTSYMS               (OPTION_DOTSYMS + 1)
 474 #define OPTION_NO_TLS_OPT               (OPTION_NO_DOTSYMS + 1)
 475 #define OPTION_NO_OPD_OPT               (OPTION_NO_TLS_OPT + 1)
 476 #define OPTION_NO_TOC_OPT               (OPTION_NO_OPD_OPT + 1)
 477 #define OPTION_NO_MULTI_TOC             (OPTION_NO_TOC_OPT + 1)
 478 #define OPTION_NON_OVERLAPPING_OPD      (OPTION_NO_MULTI_TOC + 1)
 479 '
 480
 481 PARSE_AND_LIST_LONGOPTS='
 482   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 483   { "emit-stub-syms", no_argument, NULL, OPTION_STUBSYMS },
 484   { "dotsyms", no_argument, NULL, OPTION_DOTSYMS },
 485   { "no-dotsyms", no_argument, NULL, OPTION_NO_DOTSYMS },
 486   { "no-tls-optimize", no_argument, NULL, OPTION_NO_TLS_OPT },
 487   { "no-opd-optimize", no_argument, NULL, OPTION_NO_OPD_OPT },
 488   { "no-toc-optimize", no_argument, NULL, OPTION_NO_TOC_OPT },
 489   { "no-multi-toc", no_argument, NULL, OPTION_NO_MULTI_TOC },
 490   { "non-overlapping-opd", no_argument, NULL, OPTION_NON_OVERLAPPING_OPD },
 491 '
 492
 493 PARSE_AND_LIST_OPTIONS='
 494   fprintf (file, _("\
 495   --stub-group-size=N   Maximum size of a group of input sections that can be\n\
 496                           handled by one stub section.  A negative value\n\
 497                           locates all stubs before their branches (with a\n\
 498                           group size of -N), while a positive value allows\n\
 499                           two groups of input sections, one before, and one\n\
 500                           after each stub section.  Values of +/-1 indicate\n\
 501                           the linker should choose suitable defaults.\n"
 502                    ));
 503   fprintf (file, _("\
 504   --emit-stub-syms      Label linker stubs with a symbol.\n"
 505                    ));
 506   fprintf (file, _("\
 507   --dotsyms             For every version pattern \"foo\" in a version script,\n\
 508                           add \".foo\" so that function code symbols are\n\
 509                           treated the same as function descriptor symbols.\n\
 510                           Defaults to on.\n"
 511                    ));
 512   fprintf (file, _("\
 513   --no-dotsyms          Don'\''t do anything special in version scripts.\n"
 514                    ));
 515   fprintf (file, _("\
 516   --no-tls-optimize     Don'\''t try to optimize TLS accesses.\n"
 517                    ));
 518   fprintf (file, _("\
 519   --no-opd-optimize     Don'\''t optimize the OPD section.\n"
 520                    ));
 521   fprintf (file, _("\
 522   --no-toc-optimize     Don'\''t optimize the TOC section.\n"
 523                    ));
 524   fprintf (file, _("\
 525   --no-multi-toc        Disallow automatic multiple toc sections.\n"
 526                    ));
 527   fprintf (file, _("\
 528   --non-overlapping-opd Canonicalize .opd, so that there are no overlapping\n\
 529                           .opd entries.\n"
 530                    ));
 531 '
 532
 533 PARSE_AND_LIST_ARGS_CASES='
 534     case OPTION_STUBGROUP_SIZE:
 535       {
 536         const char *end;
 537         group_size = bfd_scan_vma (optarg, &end, 0);
 538         if (*end)
 539           einfo (_("%P%F: invalid number `%s'\''\n"), optarg);
 540       }
 541       break;
 542
 543     case OPTION_STUBSYMS:
 544       emit_stub_syms = 1;
 545       break;
 546
 547     case OPTION_DOTSYMS:
 548       dotsyms = 1;
 549       break;
 550
 551     case OPTION_NO_DOTSYMS:
 552       dotsyms = 0;
 553       break;
 554
 555     case OPTION_NO_TLS_OPT:
 556       no_tls_opt = 1;
 557       break;
 558
 559     case OPTION_NO_OPD_OPT:
 560       no_opd_opt = 1;
 561       break;
 562
 563     case OPTION_NO_TOC_OPT:
 564       no_toc_opt = 1;
 565       break;
 566
 567     case OPTION_NO_MULTI_TOC:
 568       no_multi_toc = 1;
 569       break;
 570
 571     case OPTION_NON_OVERLAPPING_OPD:
 572       non_overlapping_opd = 1;
 573       break;
 574 '
 575
 576 # Put these extra ppc64elf routines in ld_${EMULATION_NAME}_emulation
 577 #
 578 LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
 579 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 580 LDEMUL_FINISH=ppc_finish
 581 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_create_output_section_statements
 582 LDEMUL_NEW_VERS_PATTERN=gld${EMULATION_NAME}_new_vers_pattern