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