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 notlsopt = 0;
  48
  49 /* Whether to emit symbols for stubs.  */
  50 static int emit_stub_syms = 0;
  51
  52 static asection *toc_section = 0;
  53
  54 /* Whether to canonicalize .opd so that there are no overlapping
  55    .opd entries.  */
  56 static int non_overlapping_opd = 0;
  57
  58 /* This is called before the input files are opened.  We create a new
  59    fake input file to hold the stub sections.  */
  60
  61 static void
  62 ppc_create_output_section_statements (void)
  63 {
  64   extern const bfd_target bfd_elf64_powerpc_vec;
  65   extern const bfd_target bfd_elf64_powerpcle_vec;
  66
  67   if (link_info.hash->creator != &bfd_elf64_powerpc_vec
  68       && link_info.hash->creator != &bfd_elf64_powerpcle_vec)
  69     return;
  70
  71   link_info.wrap_char = '.';
  72
  73   stub_file = lang_add_input_file ("linker stubs",
  74                                    lang_input_file_is_fake_enum,
  75                                    NULL);
  76   stub_file->the_bfd = bfd_create ("linker stubs", output_bfd);
  77   if (stub_file->the_bfd == NULL
  78       || !bfd_set_arch_mach (stub_file->the_bfd,
  79                              bfd_get_arch (output_bfd),
  80                              bfd_get_mach (output_bfd)))
  81     {
  82       einfo ("%X%P: can not create BFD %E\n");
  83       return;
  84     }
  85
  86   ldlang_add_file (stub_file);
  87   ppc64_elf_init_stub_bfd (stub_file->the_bfd, &link_info);
  88 }
  89
  90 static void
  91 ppc_before_allocation (void)
  92 {
  93   if (stub_file != NULL)
  94     {
  95       if (!ppc64_elf_edit_opd (output_bfd, &link_info, non_overlapping_opd))
  96         {
  97           einfo ("%X%P: can not edit opd %E\n");
  98           return;
  99         }
 100
 101       if (ppc64_elf_tls_setup (output_bfd, &link_info) && !notlsopt)
 102         {
 103           /* Size the sections.  This is premature, but we want to know the
 104              TLS segment layout so that certain optimizations can be done.  */
 105           lang_size_sections (stat_ptr->head, abs_output_section,
 106                               &stat_ptr->head, 0, 0, NULL, TRUE);
 107
 108           if (!ppc64_elf_tls_optimize (output_bfd, &link_info))
 109             {
 110               einfo ("%X%P: TLS problem %E\n");
 111               return;
 112             }
 113
 114           /* We must not cache anything from the preliminary sizing.  */
 115           elf_tdata (output_bfd)->program_header_size = 0;
 116           lang_reset_memory_regions ();
 117         }
 118     }
 119
 120   gld${EMULATION_NAME}_before_allocation ();
 121 }
 122
 123 struct hook_stub_info
 124 {
 125   lang_statement_list_type add;
 126   asection *input_section;
 127 };
 128
 129 /* Traverse the linker tree to find the spot where the stub goes.  */
 130
 131 static bfd_boolean
 132 hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp)
 133 {
 134   lang_statement_union_type *l;
 135   bfd_boolean ret;
 136
 137   for (; (l = *lp) != NULL; lp = &l->header.next)
 138     {
 139       switch (l->header.type)
 140         {
 141         case lang_constructors_statement_enum:
 142           ret = hook_in_stub (info, &constructor_list.head);
 143           if (ret)
 144             return ret;
 145           break;
 146
 147         case lang_output_section_statement_enum:
 148           ret = hook_in_stub (info,
 149                               &l->output_section_statement.children.head);
 150           if (ret)
 151             return ret;
 152           break;
 153
 154         case lang_wild_statement_enum:
 155           ret = hook_in_stub (info, &l->wild_statement.children.head);
 156           if (ret)
 157             return ret;
 158           break;
 159
 160         case lang_group_statement_enum:
 161           ret = hook_in_stub (info, &l->group_statement.children.head);
 162           if (ret)
 163             return ret;
 164           break;
 165
 166         case lang_input_section_enum:
 167           if (l->input_section.section == info->input_section)
 168             {
 169               /* We've found our section.  Insert the stub immediately
 170                  before its associated input section.  */
 171               *lp = info->add.head;
 172               *(info->add.tail) = l;
 173               return TRUE;
 174             }
 175           break;
 176
 177         case lang_data_statement_enum:
 178         case lang_reloc_statement_enum:
 179         case lang_object_symbols_statement_enum:
 180         case lang_output_statement_enum:
 181         case lang_target_statement_enum:
 182         case lang_input_statement_enum:
 183         case lang_assignment_statement_enum:
 184         case lang_padding_statement_enum:
 185         case lang_address_statement_enum:
 186         case lang_fill_statement_enum:
 187           break;
 188
 189         default:
 190           FAIL ();
 191           break;
 192         }
 193     }
 194   return FALSE;
 195 }
 196
 197
 198 /* Call-back for ppc64_elf_size_stubs.  */
 199
 200 /* Create a new stub section, and arrange for it to be linked
 201    immediately before INPUT_SECTION.  */
 202
 203 static asection *
 204 ppc_add_stub_section (const char *stub_sec_name, asection *input_section)
 205 {
 206   asection *stub_sec;
 207   flagword flags;
 208   asection *output_section;
 209   const char *secname;
 210   lang_output_section_statement_type *os;
 211   struct hook_stub_info info;
 212
 213   stub_sec = bfd_make_section_anyway (stub_file->the_bfd, stub_sec_name);
 214   if (stub_sec == NULL)
 215     goto err_ret;
 216
 217   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 218            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 219   if (!bfd_set_section_flags (stub_file->the_bfd, stub_sec, flags))
 220     goto err_ret;
 221
 222   output_section = input_section->output_section;
 223   secname = bfd_get_section_name (output_section->owner, output_section);
 224   os = lang_output_section_find (secname);
 225
 226   info.input_section = input_section;
 227   lang_list_init (&info.add);
 228   lang_add_section (&info.add, stub_sec, os, stub_file);
 229
 230   if (info.add.head == NULL)
 231     goto err_ret;
 232
 233   stub_added = 1;
 234   if (hook_in_stub (&info, &os->children.head))
 235     return stub_sec;
 236
 237  err_ret:
 238   einfo ("%X%P: can not make stub section: %E\n");
 239   return NULL;
 240 }
 241
 242
 243 /* Another call-back for ppc64_elf_size_stubs.  */
 244
 245 static void
 246 ppc_layout_sections_again (void)
 247 {
 248   /* If we have changed sizes of the stub sections, then we need
 249      to recalculate all the section offsets.  This may mean we need to
 250      add even more stubs.  */
 251   need_laying_out = 0;
 252
 253   lang_reset_memory_regions ();
 254
 255   /* Resize the sections.  */
 256   lang_size_sections (stat_ptr->head, abs_output_section,
 257                       &stat_ptr->head, 0, 0, NULL, TRUE);
 258
 259   /* Recalculate TOC base.  */
 260   ldemul_after_allocation ();
 261
 262   /* Do the assignments again.  */
 263   lang_do_assignments (stat_ptr->head, abs_output_section, NULL, 0);
 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${EMULATION_NAME}_after_allocation (void)
 271 {
 272   if (!link_info.relocatable)
 273     _bfd_set_gp_value (output_bfd, ppc64_elf_toc (output_bfd));
 274 }
 275
 276
 277 static void
 278 build_toc_list (lang_statement_union_type *statement)
 279 {
 280   if (statement->header.type == lang_input_section_enum
 281       && !statement->input_section.ifile->just_syms_flag
 282       && (statement->input_section.section->flags & SEC_EXCLUDE) == 0
 283       && statement->input_section.section->output_section == toc_section)
 284     ppc64_elf_next_toc_section (&link_info, statement->input_section.section);
 285 }
 286
 287
 288 static void
 289 build_section_lists (lang_statement_union_type *statement)
 290 {
 291   if (statement->header.type == lang_input_section_enum
 292       && !statement->input_section.ifile->just_syms_flag
 293       && (statement->input_section.section->flags & SEC_EXCLUDE) == 0
 294       && statement->input_section.section->output_section != NULL
 295       && statement->input_section.section->output_section->owner == output_bfd)
 296     {
 297       if (!ppc64_elf_next_input_section (&link_info,
 298                                          statement->input_section.section))
 299         einfo ("%X%P: can not size stub section: %E\n");
 300     }
 301 }
 302
 303
 304 /* Final emulation specific call.  */
 305
 306 static void
 307 gld${EMULATION_NAME}_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       if (ret != 0)
 327         {
 328           if (ret < 0)
 329             {
 330               einfo ("%X%P: can not size stub section: %E\n");
 331               return;
 332             }
 333
 334           toc_section = bfd_get_section_by_name (output_bfd, ".got");
 335           if (toc_section != NULL)
 336             lang_for_each_statement (build_toc_list);
 337
 338           ppc64_elf_reinit_toc (output_bfd, &link_info);
 339
 340           lang_for_each_statement (build_section_lists);
 341
 342           /* Call into the BFD backend to do the real work.  */
 343           if (!ppc64_elf_size_stubs (output_bfd,
 344                                      &link_info,
 345                                      group_size,
 346                                      &ppc_add_stub_section,
 347                                      &ppc_layout_sections_again))
 348             {
 349               einfo ("%X%P: can not size stub section: %E\n");
 350               return;
 351             }
 352         }
 353     }
 354
 355   if (need_laying_out)
 356     ppc_layout_sections_again ();
 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 }
 389
 390
 391 /* Add a pattern matching ".foo" for every "foo" in a version script.
 392
 393    The reason for doing this is that many shared library version
 394    scripts export a selected set of functions or data symbols, forcing
 395    others local.  eg.
 396
 397    . VERS_1 {
 398    .       global:
 399    .               this; that; some; thing;
 400    .       local:
 401    .               *;
 402    .   };
 403
 404    To make the above work for PowerPC64, we need to export ".this",
 405    ".that" and so on, otherwise only the function descriptor syms are
 406    exported.  Lack of an exported function code sym may cause a
 407    definition to be pulled in from a static library.  */
 408
 409 static struct bfd_elf_version_expr *
 410 gld${EMULATION_NAME}_new_vers_pattern (struct bfd_elf_version_expr *entry)
 411 {
 412   struct bfd_elf_version_expr *dot_entry;
 413   unsigned int len;
 414   char *dot_pat;
 415
 416   if (!dotsyms || entry->pattern[0] == '*' || entry->pattern[0] == '.')
 417     return entry;
 418
 419   dot_entry = xmalloc (sizeof *dot_entry);
 420   *dot_entry = *entry;
 421   dot_entry->next = entry;
 422   len = strlen (entry->pattern) + 2;
 423   dot_pat = xmalloc (len);
 424   dot_pat[0] = '.';
 425   memcpy (dot_pat + 1, entry->pattern, len - 1);
 426   dot_entry->pattern = dot_pat;
 427   if (entry->symbol != NULL)
 428     {
 429       len = strlen (entry->symbol) + 2;
 430       dot_pat = xmalloc (len);
 431       dot_pat[0] = '.';
 432       memcpy (dot_pat + 1, entry->symbol, len - 1);
 433       dot_entry->symbol = dot_pat;
 434     }
 435   return dot_entry;
 436 }
 437
 438
 439 /* Avoid processing the fake stub_file in vercheck, stat_needed and
 440    check_needed routines.  */
 441
 442 static void (*real_func) (lang_input_statement_type *);
 443
 444 static void ppc_for_each_input_file_wrapper (lang_input_statement_type *l)
 445 {
 446   if (l != stub_file)
 447     (*real_func) (l);
 448 }
 449
 450 static void
 451 ppc_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
 452 {
 453   real_func = func;
 454   lang_for_each_input_file (&ppc_for_each_input_file_wrapper);
 455 }
 456
 457 #define lang_for_each_input_file ppc_lang_for_each_input_file
 458
 459 EOF
 460
 461 # Define some shell vars to insert bits of code into the standard elf
 462 # parse_args and list_options functions.
 463 #
 464 PARSE_AND_LIST_PROLOGUE='
 465 #define OPTION_STUBGROUP_SIZE           301
 466 #define OPTION_STUBSYMS                 (OPTION_STUBGROUP_SIZE + 1)
 467 #define OPTION_DOTSYMS                  (OPTION_STUBSYMS + 1)
 468 #define OPTION_NO_DOTSYMS               (OPTION_DOTSYMS + 1)
 469 #define OPTION_NO_TLS_OPT               (OPTION_NO_DOTSYMS + 1)
 470 #define OPTION_NON_OVERLAPPING_OPD      (OPTION_NO_TLS_OPT + 1)
 471 '
 472
 473 PARSE_AND_LIST_LONGOPTS='
 474   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 475   { "emit-stub-syms", no_argument, NULL, OPTION_STUBSYMS },
 476   { "dotsyms", no_argument, NULL, OPTION_DOTSYMS },
 477   { "no-dotsyms", no_argument, NULL, OPTION_NO_DOTSYMS },
 478   { "no-tls-optimize", no_argument, NULL, OPTION_NO_TLS_OPT },
 479   { "non-overlapping-opd", no_argument, NULL, OPTION_NON_OVERLAPPING_OPD },
 480 '
 481
 482 PARSE_AND_LIST_OPTIONS='
 483   fprintf (file, _("\
 484   --stub-group-size=N   Maximum size of a group of input sections that can be\n\
 485                           handled by one stub section.  A negative value\n\
 486                           locates all stubs before their branches (with a\n\
 487                           group size of -N), while a positive value allows\n\
 488                           two groups of input sections, one before, and one\n\
 489                           after each stub section.  Values of +/-1 indicate\n\
 490                           the linker should choose suitable defaults.\n"
 491                    ));
 492   fprintf (file, _("\
 493   --emit-stub-syms      Label linker stubs with a symbol.\n"
 494                    ));
 495   fprintf (file, _("\
 496   --dotsyms             For every version pattern \"foo\" in a version script,\n\
 497                           add \".foo\" so that function code symbols are\n\
 498                           treated the same as function descriptor symbols.\n\
 499                           Defaults to on.\n"
 500                    ));
 501   fprintf (file, _("\
 502   --no-dotsyms          Don'\''t do anything special in version scripts.\n"
 503                    ));
 504   fprintf (file, _("\
 505   --no-tls-optimize     Don'\''t try to optimize TLS accesses.\n"
 506                    ));
 507   fprintf (file, _("\
 508   --non-overlapping-opd Canonicalize .opd, so that there are no overlapping\n\
 509                           .opd entries.\n"
 510                    ));
 511 '
 512
 513 PARSE_AND_LIST_ARGS_CASES='
 514     case OPTION_STUBGROUP_SIZE:
 515       {
 516         const char *end;
 517         group_size = bfd_scan_vma (optarg, &end, 0);
 518         if (*end)
 519           einfo (_("%P%F: invalid number `%s'\''\n"), optarg);
 520       }
 521       break;
 522
 523     case OPTION_STUBSYMS:
 524       emit_stub_syms = 1;
 525       break;
 526
 527     case OPTION_DOTSYMS:
 528       dotsyms = 1;
 529       break;
 530
 531     case OPTION_NO_DOTSYMS:
 532       dotsyms = 0;
 533       break;
 534
 535     case OPTION_NO_TLS_OPT:
 536       notlsopt = 1;
 537       break;
 538
 539     case OPTION_NON_OVERLAPPING_OPD:
 540       non_overlapping_opd = 1;
 541       break;
 542 '
 543
 544 # Put these extra ppc64elf routines in ld_${EMULATION_NAME}_emulation
 545 #
 546 LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
 547 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 548 LDEMUL_FINISH=gld${EMULATION_NAME}_finish
 549 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_create_output_section_statements
 550 LDEMUL_NEW_VERS_PATTERN=gld${EMULATION_NAME}_new_vers_pattern