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