ld/emultempl/ppc64elf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright 2002, 2003, 2004 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 ("%X%P: can not create BFD %E\n");
  92       return;
  93     }
  94
  95   ldlang_add_file (stub_file);
  96   ppc64_elf_init_stub_bfd (stub_file->the_bfd, &link_info);
  97 }
  98
  99 static void
 100 ppc_before_allocation (void)
 101 {
 102   if (stub_file != NULL)
 103     {
 104       if (!no_opd_opt
 105           && !ppc64_elf_edit_opd (output_bfd, &link_info, non_overlapping_opd))
 106         {
 107           einfo ("%X%P: can not edit %s %E\n", "opd");
 108           return;
 109         }
 110
 111       if (ppc64_elf_tls_setup (output_bfd, &link_info) && !no_tls_opt)
 112         {
 113           /* Size the sections.  This is premature, but we want to know the
 114              TLS segment layout so that certain optimizations can be done.  */
 115           lang_size_sections (stat_ptr->head, abs_output_section,
 116                               &stat_ptr->head, 0, 0, NULL, TRUE);
 117
 118           if (!ppc64_elf_tls_optimize (output_bfd, &link_info))
 119             {
 120               einfo ("%X%P: TLS problem %E\n");
 121               return;
 122             }
 123
 124           /* We must not cache anything from the preliminary sizing.  */
 125           elf_tdata (output_bfd)->program_header_size = 0;
 126           lang_reset_memory_regions ();
 127         }
 128
 129       if (!no_toc_opt
 130           && !link_info.relocatable
 131           && !ppc64_elf_edit_toc (output_bfd, &link_info))
 132         {
 133           einfo ("%X%P: can not edit %s %E\n", "toc");
 134           return;
 135         }
 136     }
 137
 138   gld${EMULATION_NAME}_before_allocation ();
 139 }
 140
 141 struct hook_stub_info
 142 {
 143   lang_statement_list_type add;
 144   asection *input_section;
 145 };
 146
 147 /* Traverse the linker tree to find the spot where the stub goes.  */
 148
 149 static bfd_boolean
 150 hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp)
 151 {
 152   lang_statement_union_type *l;
 153   bfd_boolean ret;
 154
 155   for (; (l = *lp) != NULL; lp = &l->header.next)
 156     {
 157       switch (l->header.type)
 158         {
 159         case lang_constructors_statement_enum:
 160           ret = hook_in_stub (info, &constructor_list.head);
 161           if (ret)
 162             return ret;
 163           break;
 164
 165         case lang_output_section_statement_enum:
 166           ret = hook_in_stub (info,
 167                               &l->output_section_statement.children.head);
 168           if (ret)
 169             return ret;
 170           break;
 171
 172         case lang_wild_statement_enum:
 173           ret = hook_in_stub (info, &l->wild_statement.children.head);
 174           if (ret)
 175             return ret;
 176           break;
 177
 178         case lang_group_statement_enum:
 179           ret = hook_in_stub (info, &l->group_statement.children.head);
 180           if (ret)
 181             return ret;
 182           break;
 183
 184         case lang_input_section_enum:
 185           if (l->input_section.section == info->input_section)
 186             {
 187               /* We've found our section.  Insert the stub immediately
 188                  before its associated input section.  */
 189               *lp = info->add.head;
 190               *(info->add.tail) = l;
 191               return TRUE;
 192             }
 193           break;
 194
 195         case lang_data_statement_enum:
 196         case lang_reloc_statement_enum:
 197         case lang_object_symbols_statement_enum:
 198         case lang_output_statement_enum:
 199         case lang_target_statement_enum:
 200         case lang_input_statement_enum:
 201         case lang_assignment_statement_enum:
 202         case lang_padding_statement_enum:
 203         case lang_address_statement_enum:
 204         case lang_fill_statement_enum:
 205           break;
 206
 207         default:
 208           FAIL ();
 209           break;
 210         }
 211     }
 212   return FALSE;
 213 }
 214
 215
 216 /* Call-back for ppc64_elf_size_stubs.  */
 217
 218 /* Create a new stub section, and arrange for it to be linked
 219    immediately before INPUT_SECTION.  */
 220
 221 static asection *
 222 ppc_add_stub_section (const char *stub_sec_name, asection *input_section)
 223 {
 224   asection *stub_sec;
 225   flagword flags;
 226   asection *output_section;
 227   const char *secname;
 228   lang_output_section_statement_type *os;
 229   struct hook_stub_info info;
 230
 231   stub_sec = bfd_make_section_anyway (stub_file->the_bfd, stub_sec_name);
 232   if (stub_sec == NULL)
 233     goto err_ret;
 234
 235   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 236            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 237   if (!bfd_set_section_flags (stub_file->the_bfd, stub_sec, flags))
 238     goto err_ret;
 239
 240   output_section = input_section->output_section;
 241   secname = bfd_get_section_name (output_section->owner, output_section);
 242   os = lang_output_section_find (secname);
 243
 244   info.input_section = input_section;
 245   lang_list_init (&info.add);
 246   lang_add_section (&info.add, stub_sec, os, stub_file);
 247
 248   if (info.add.head == NULL)
 249     goto err_ret;
 250
 251   stub_added = 1;
 252   if (hook_in_stub (&info, &os->children.head))
 253     return stub_sec;
 254
 255  err_ret:
 256   einfo ("%X%P: can not make stub section: %E\n");
 257   return NULL;
 258 }
 259
 260
 261 /* Another call-back for ppc64_elf_size_stubs.  */
 262
 263 static void
 264 ppc_layout_sections_again (void)
 265 {
 266   /* If we have changed sizes of the stub sections, then we need
 267      to recalculate all the section offsets.  This may mean we need to
 268      add even more stubs.  */
 269   need_laying_out = 0;
 270
 271   lang_reset_memory_regions ();
 272
 273   /* Resize the sections.  */
 274   lang_size_sections (stat_ptr->head, abs_output_section,
 275                       &stat_ptr->head, 0, 0, NULL, TRUE);
 276
 277   /* Recalculate TOC base.  */
 278   ldemul_after_allocation ();
 279
 280   /* Do the assignments again.  */
 281   lang_do_assignments (stat_ptr->head, abs_output_section, NULL, 0);
 282 }
 283
 284
 285 /* Call the back-end function to set TOC base after we have placed all
 286    the sections.  */
 287 static void
 288 gld${EMULATION_NAME}_after_allocation (void)
 289 {
 290   if (!link_info.relocatable)
 291     _bfd_set_gp_value (output_bfd, ppc64_elf_toc (output_bfd));
 292 }
 293
 294
 295 static void
 296 build_toc_list (lang_statement_union_type *statement)
 297 {
 298   if (statement->header.type == lang_input_section_enum
 299       && !statement->input_section.ifile->just_syms_flag
 300       && (statement->input_section.section->flags & SEC_EXCLUDE) == 0
 301       && statement->input_section.section->output_section == toc_section)
 302     ppc64_elf_next_toc_section (&link_info, statement->input_section.section);
 303 }
 304
 305
 306 static void
 307 build_section_lists (lang_statement_union_type *statement)
 308 {
 309   if (statement->header.type == lang_input_section_enum
 310       && !statement->input_section.ifile->just_syms_flag
 311       && (statement->input_section.section->flags & SEC_EXCLUDE) == 0
 312       && statement->input_section.section->output_section != NULL
 313       && statement->input_section.section->output_section->owner == output_bfd)
 314     {
 315       if (!ppc64_elf_next_input_section (&link_info,
 316                                          statement->input_section.section))
 317         einfo ("%X%P: can not size stub section: %E\n");
 318     }
 319 }
 320
 321
 322 /* Final emulation specific call.  */
 323
 324 static void
 325 gld${EMULATION_NAME}_finish (void)
 326 {
 327   /* e_entry on PowerPC64 points to the function descriptor for
 328      _start.  If _start is missing, default to the first function
 329      descriptor in the .opd section.  */
 330   entry_section = ".opd";
 331
 332   /* bfd_elf_discard_info just plays with debugging sections,
 333      ie. doesn't affect any code, so we can delay resizing the
 334      sections.  It's likely we'll resize everything in the process of
 335      adding stubs.  */
 336   if (bfd_elf_discard_info (output_bfd, &link_info))
 337     need_laying_out = 1;
 338
 339   /* If generating a relocatable output file, then we don't have any
 340      stubs.  */
 341   if (stub_file != NULL && !link_info.relocatable)
 342     {
 343       int ret = ppc64_elf_setup_section_lists (output_bfd, &link_info,
 344                                                no_multi_toc);
 345       if (ret != 0)
 346         {
 347           if (ret < 0)
 348             {
 349               einfo ("%X%P: can not size stub section: %E\n");
 350               return;
 351             }
 352
 353           toc_section = bfd_get_section_by_name (output_bfd, ".got");
 354           if (toc_section != NULL)
 355             lang_for_each_statement (build_toc_list);
 356
 357           ppc64_elf_reinit_toc (output_bfd, &link_info);
 358
 359           lang_for_each_statement (build_section_lists);
 360
 361           /* Call into the BFD backend to do the real work.  */
 362           if (!ppc64_elf_size_stubs (output_bfd,
 363                                      &link_info,
 364                                      group_size,
 365                                      &ppc_add_stub_section,
 366                                      &ppc_layout_sections_again))
 367             {
 368               einfo ("%X%P: can not size stub section: %E\n");
 369               return;
 370             }
 371         }
 372     }
 373
 374   if (need_laying_out)
 375     ppc_layout_sections_again ();
 376
 377   if (link_info.relocatable)
 378     {
 379       asection *toc = bfd_get_section_by_name (output_bfd, ".toc");
 380       if (toc != NULL
 381           && bfd_section_size (output_bfd, toc) > 0x10000)
 382         einfo ("%X%P: TOC section size exceeds 64k\n");
 383     }
 384
 385   if (stub_added)
 386     {
 387       char *msg = NULL;
 388       char *line, *endline;
 389
 390       emit_stub_syms |= link_info.emitrelocations;
 391       if (!ppc64_elf_build_stubs (emit_stub_syms, &link_info,
 392                                   config.stats ? &msg : NULL))
 393         einfo ("%X%P: can not build stubs: %E\n");
 394
 395       for (line = msg; line != NULL; line = endline)
 396         {
 397           endline = strchr (line, '\n');
 398           if (endline != NULL)
 399             *endline++ = '\0';
 400           fprintf (stderr, "%s: %s\n", program_name, line);
 401         }
 402       if (msg != NULL)
 403         free (msg);
 404     }
 405
 406   ppc64_elf_restore_symbols (&link_info);
 407 }
 408
 409
 410 /* Add a pattern matching ".foo" for every "foo" in a version script.
 411
 412    The reason for doing this is that many shared library version
 413    scripts export a selected set of functions or data symbols, forcing
 414    others local.  eg.
 415
 416    . VERS_1 {
 417    .       global:
 418    .               this; that; some; thing;
 419    .       local:
 420    .               *;
 421    .   };
 422
 423    To make the above work for PowerPC64, we need to export ".this",
 424    ".that" and so on, otherwise only the function descriptor syms are
 425    exported.  Lack of an exported function code sym may cause a
 426    definition to be pulled in from a static library.  */
 427
 428 static struct bfd_elf_version_expr *
 429 gld${EMULATION_NAME}_new_vers_pattern (struct bfd_elf_version_expr *entry)
 430 {
 431   struct bfd_elf_version_expr *dot_entry;
 432   unsigned int len;
 433   char *dot_pat;
 434
 435   if (!dotsyms || entry->pattern[0] == '*' || entry->pattern[0] == '.')
 436     return entry;
 437
 438   dot_entry = xmalloc (sizeof *dot_entry);
 439   *dot_entry = *entry;
 440   dot_entry->next = entry;
 441   len = strlen (entry->pattern) + 2;
 442   dot_pat = xmalloc (len);
 443   dot_pat[0] = '.';
 444   memcpy (dot_pat + 1, entry->pattern, len - 1);
 445   dot_entry->pattern = dot_pat;
 446   if (entry->symbol != NULL)
 447     {
 448       len = strlen (entry->symbol) + 2;
 449       dot_pat = xmalloc (len);
 450       dot_pat[0] = '.';
 451       memcpy (dot_pat + 1, entry->symbol, len - 1);
 452       dot_entry->symbol = dot_pat;
 453     }
 454   return dot_entry;
 455 }
 456
 457
 458 /* Avoid processing the fake stub_file in vercheck, stat_needed and
 459    check_needed routines.  */
 460
 461 static void (*real_func) (lang_input_statement_type *);
 462
 463 static void ppc_for_each_input_file_wrapper (lang_input_statement_type *l)
 464 {
 465   if (l != stub_file)
 466     (*real_func) (l);
 467 }
 468
 469 static void
 470 ppc_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
 471 {
 472   real_func = func;
 473   lang_for_each_input_file (&ppc_for_each_input_file_wrapper);
 474 }
 475
 476 #define lang_for_each_input_file ppc_lang_for_each_input_file
 477
 478 EOF
 479
 480 # Define some shell vars to insert bits of code into the standard elf
 481 # parse_args and list_options functions.
 482 #
 483 PARSE_AND_LIST_PROLOGUE='
 484 #define OPTION_STUBGROUP_SIZE           301
 485 #define OPTION_STUBSYMS                 (OPTION_STUBGROUP_SIZE + 1)
 486 #define OPTION_DOTSYMS                  (OPTION_STUBSYMS + 1)
 487 #define OPTION_NO_DOTSYMS               (OPTION_DOTSYMS + 1)
 488 #define OPTION_NO_TLS_OPT               (OPTION_NO_DOTSYMS + 1)
 489 #define OPTION_NO_OPD_OPT               (OPTION_NO_TLS_OPT + 1)
 490 #define OPTION_NO_TOC_OPT               (OPTION_NO_OPD_OPT + 1)
 491 #define OPTION_NO_MULTI_TOC             (OPTION_NO_TOC_OPT + 1)
 492 #define OPTION_NON_OVERLAPPING_OPD      (OPTION_NO_MULTI_TOC + 1)
 493 '
 494
 495 PARSE_AND_LIST_LONGOPTS='
 496   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 497   { "emit-stub-syms", no_argument, NULL, OPTION_STUBSYMS },
 498   { "dotsyms", no_argument, NULL, OPTION_DOTSYMS },
 499   { "no-dotsyms", no_argument, NULL, OPTION_NO_DOTSYMS },
 500   { "no-tls-optimize", no_argument, NULL, OPTION_NO_TLS_OPT },
 501   { "no-opd-optimize", no_argument, NULL, OPTION_NO_OPD_OPT },
 502   { "no-toc-optimize", no_argument, NULL, OPTION_NO_TOC_OPT },
 503   { "no-multi-toc", no_argument, NULL, OPTION_NO_MULTI_TOC },
 504   { "non-overlapping-opd", no_argument, NULL, OPTION_NON_OVERLAPPING_OPD },
 505 '
 506
 507 PARSE_AND_LIST_OPTIONS='
 508   fprintf (file, _("\
 509   --stub-group-size=N   Maximum size of a group of input sections that can be\n\
 510                           handled by one stub section.  A negative value\n\
 511                           locates all stubs before their branches (with a\n\
 512                           group size of -N), while a positive value allows\n\
 513                           two groups of input sections, one before, and one\n\
 514                           after each stub section.  Values of +/-1 indicate\n\
 515                           the linker should choose suitable defaults.\n"
 516                    ));
 517   fprintf (file, _("\
 518   --emit-stub-syms      Label linker stubs with a symbol.\n"
 519                    ));
 520   fprintf (file, _("\
 521   --dotsyms             For every version pattern \"foo\" in a version script,\n\
 522                           add \".foo\" so that function code symbols are\n\
 523                           treated the same as function descriptor symbols.\n\
 524                           Defaults to on.\n"
 525                    ));
 526   fprintf (file, _("\
 527   --no-dotsyms          Don'\''t do anything special in version scripts.\n"
 528                    ));
 529   fprintf (file, _("\
 530   --no-tls-optimize     Don'\''t try to optimize TLS accesses.\n"
 531                    ));
 532   fprintf (file, _("\
 533   --no-opd-optimize     Don'\''t optimize the OPD section.\n"
 534                    ));
 535   fprintf (file, _("\
 536   --no-toc-optimize     Don'\''t optimize the TOC section.\n"
 537                    ));
 538   fprintf (file, _("\
 539   --no-multi-toc        Disallow automatic multiple toc sections.\n"
 540                    ));
 541   fprintf (file, _("\
 542   --non-overlapping-opd Canonicalize .opd, so that there are no overlapping\n\
 543                           .opd entries.\n"
 544                    ));
 545 '
 546
 547 PARSE_AND_LIST_ARGS_CASES='
 548     case OPTION_STUBGROUP_SIZE:
 549       {
 550         const char *end;
 551         group_size = bfd_scan_vma (optarg, &end, 0);
 552         if (*end)
 553           einfo (_("%P%F: invalid number `%s'\''\n"), optarg);
 554       }
 555       break;
 556
 557     case OPTION_STUBSYMS:
 558       emit_stub_syms = 1;
 559       break;
 560
 561     case OPTION_DOTSYMS:
 562       dotsyms = 1;
 563       break;
 564
 565     case OPTION_NO_DOTSYMS:
 566       dotsyms = 0;
 567       break;
 568
 569     case OPTION_NO_TLS_OPT:
 570       no_tls_opt = 1;
 571       break;
 572
 573     case OPTION_NO_OPD_OPT:
 574       no_opd_opt = 1;
 575       break;
 576
 577     case OPTION_NO_TOC_OPT:
 578       no_toc_opt = 1;
 579       break;
 580
 581     case OPTION_NO_MULTI_TOC:
 582       no_multi_toc = 1;
 583       break;
 584
 585     case OPTION_NON_OVERLAPPING_OPD:
 586       non_overlapping_opd = 1;
 587       break;
 588 '
 589
 590 # Put these extra ppc64elf routines in ld_${EMULATION_NAME}_emulation
 591 #
 592 LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
 593 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 594 LDEMUL_FINISH=gld${EMULATION_NAME}_finish
 595 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_create_output_section_statements
 596 LDEMUL_NEW_VERS_PATTERN=gld${EMULATION_NAME}_new_vers_pattern