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