ld/emultempl/ppc64elf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright 2002, 2003 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   stub_file = lang_add_input_file ("linker stubs",
  69                                    lang_input_file_is_fake_enum,
  70                                    NULL);
  71   stub_file->the_bfd = bfd_create ("linker stubs", output_bfd);
  72   if (stub_file->the_bfd == NULL
  73       || !bfd_set_arch_mach (stub_file->the_bfd,
  74                              bfd_get_arch (output_bfd),
  75                              bfd_get_mach (output_bfd)))
  76     {
  77       einfo ("%X%P: can not create BFD %E\n");
  78       return;
  79     }
  80
  81   ldlang_add_file (stub_file);
  82   ppc64_elf_init_stub_bfd (stub_file->the_bfd, &link_info);
  83 }
  84
  85 static void
  86 ppc_after_open (void)
  87 {
  88   if (!ppc64_elf_mark_entry_syms (&link_info))
  89     {
  90       einfo ("%X%P: can not mark entry symbols %E\n");
  91       return;
  92     }
  93
  94   gld${EMULATION_NAME}_after_open ();
  95 }
  96
  97 static void
  98 ppc_before_allocation (void)
  99 {
 100   if (stub_file != NULL)
 101     {
 102       if (!ppc64_elf_edit_opd (output_bfd, &link_info))
 103         {
 104           einfo ("%X%P: can not edit opd %E\n");
 105           return;
 106         }
 107
 108       if (ppc64_elf_tls_setup (output_bfd, &link_info) && !notlsopt)
 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
 127   gld${EMULATION_NAME}_before_allocation ();
 128 }
 129
 130 struct hook_stub_info
 131 {
 132   lang_statement_list_type add;
 133   asection *input_section;
 134 };
 135
 136 /* Traverse the linker tree to find the spot where the stub goes.  */
 137
 138 static bfd_boolean
 139 hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp)
 140 {
 141   lang_statement_union_type *l;
 142   bfd_boolean ret;
 143
 144   for (; (l = *lp) != NULL; lp = &l->header.next)
 145     {
 146       switch (l->header.type)
 147         {
 148         case lang_constructors_statement_enum:
 149           ret = hook_in_stub (info, &constructor_list.head);
 150           if (ret)
 151             return ret;
 152           break;
 153
 154         case lang_output_section_statement_enum:
 155           ret = hook_in_stub (info,
 156                               &l->output_section_statement.children.head);
 157           if (ret)
 158             return ret;
 159           break;
 160
 161         case lang_wild_statement_enum:
 162           ret = hook_in_stub (info, &l->wild_statement.children.head);
 163           if (ret)
 164             return ret;
 165           break;
 166
 167         case lang_group_statement_enum:
 168           ret = hook_in_stub (info, &l->group_statement.children.head);
 169           if (ret)
 170             return ret;
 171           break;
 172
 173         case lang_input_section_enum:
 174           if (l->input_section.section == info->input_section)
 175             {
 176               /* We've found our section.  Insert the stub immediately
 177                  before its associated input section.  */
 178               *lp = info->add.head;
 179               *(info->add.tail) = l;
 180               return TRUE;
 181             }
 182           break;
 183
 184         case lang_data_statement_enum:
 185         case lang_reloc_statement_enum:
 186         case lang_object_symbols_statement_enum:
 187         case lang_output_statement_enum:
 188         case lang_target_statement_enum:
 189         case lang_input_statement_enum:
 190         case lang_assignment_statement_enum:
 191         case lang_padding_statement_enum:
 192         case lang_address_statement_enum:
 193         case lang_fill_statement_enum:
 194           break;
 195
 196         default:
 197           FAIL ();
 198           break;
 199         }
 200     }
 201   return FALSE;
 202 }
 203
 204
 205 /* Call-back for ppc64_elf_size_stubs.  */
 206
 207 /* Create a new stub section, and arrange for it to be linked
 208    immediately before INPUT_SECTION.  */
 209
 210 static asection *
 211 ppc_add_stub_section (const char *stub_sec_name, asection *input_section)
 212 {
 213   asection *stub_sec;
 214   flagword flags;
 215   asection *output_section;
 216   const char *secname;
 217   lang_output_section_statement_type *os;
 218   struct hook_stub_info info;
 219
 220   stub_sec = bfd_make_section_anyway (stub_file->the_bfd, stub_sec_name);
 221   if (stub_sec == NULL)
 222     goto err_ret;
 223
 224   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 225            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 226   if (!bfd_set_section_flags (stub_file->the_bfd, stub_sec, flags))
 227     goto err_ret;
 228
 229   output_section = input_section->output_section;
 230   secname = bfd_get_section_name (output_section->owner, output_section);
 231   os = lang_output_section_find (secname);
 232
 233   info.input_section = input_section;
 234   lang_list_init (&info.add);
 235   lang_add_section (&info.add, stub_sec, os, stub_file);
 236
 237   if (info.add.head == NULL)
 238     goto err_ret;
 239
 240   stub_added = 1;
 241   if (hook_in_stub (&info, &os->children.head))
 242     return stub_sec;
 243
 244  err_ret:
 245   einfo ("%X%P: can not make stub section: %E\n");
 246   return NULL;
 247 }
 248
 249
 250 /* Another call-back for ppc64_elf_size_stubs.  */
 251
 252 static void
 253 ppc_layout_sections_again (void)
 254 {
 255   /* If we have changed sizes of the stub sections, then we need
 256      to recalculate all the section offsets.  This may mean we need to
 257      add even more stubs.  */
 258   need_laying_out = 0;
 259
 260   lang_reset_memory_regions ();
 261
 262   /* Resize the sections.  */
 263   lang_size_sections (stat_ptr->head, abs_output_section,
 264                       &stat_ptr->head, 0, 0, NULL, TRUE);
 265
 266   /* Recalculate TOC base.  */
 267   ldemul_after_allocation ();
 268
 269   /* Do the assignments again.  */
 270   lang_do_assignments (stat_ptr->head, abs_output_section, NULL, 0);
 271 }
 272
 273
 274 /* Call the back-end function to set TOC base after we have placed all
 275    the sections.  */
 276 static void
 277 gld${EMULATION_NAME}_after_allocation (void)
 278 {
 279   if (!link_info.relocatable)
 280     _bfd_set_gp_value (output_bfd, ppc64_elf_toc (output_bfd));
 281 }
 282
 283
 284 static void
 285 build_toc_list (lang_statement_union_type *statement)
 286 {
 287   if (statement->header.type == lang_input_section_enum
 288       && !statement->input_section.ifile->just_syms_flag
 289       && statement->input_section.section->output_section == toc_section)
 290     ppc64_elf_next_toc_section (&link_info, statement->input_section.section);
 291 }
 292
 293
 294 static void
 295 build_section_lists (lang_statement_union_type *statement)
 296 {
 297   if (statement->header.type == lang_input_section_enum
 298       && !statement->input_section.ifile->just_syms_flag
 299       && statement->input_section.section->output_section != NULL
 300       && statement->input_section.section->output_section->owner == output_bfd)
 301     {
 302       if (!ppc64_elf_next_input_section (&link_info,
 303                                          statement->input_section.section))
 304         einfo ("%X%P: can not size stub section: %E\n");
 305     }
 306 }
 307
 308
 309 /* Final emulation specific call.  */
 310
 311 static void
 312 gld${EMULATION_NAME}_finish (void)
 313 {
 314   /* e_entry on PowerPC64 points to the function descriptor for
 315      _start.  If _start is missing, default to the first function
 316      descriptor in the .opd section.  */
 317   entry_section = ".opd";
 318
 319   /* bfd_elf64_discard_info just plays with debugging sections,
 320      ie. doesn't affect any code, so we can delay resizing the
 321      sections.  It's likely we'll resize everything in the process of
 322      adding stubs.  */
 323   if (bfd_elf${ELFSIZE}_discard_info (output_bfd, &link_info))
 324     need_laying_out = 1;
 325
 326   /* If generating a relocatable output file, then we don't have any
 327      stubs.  */
 328   if (stub_file != NULL && !link_info.relocatable)
 329     {
 330       int ret = ppc64_elf_setup_section_lists (output_bfd, &link_info);
 331       if (ret != 0)
 332         {
 333           if (ret < 0)
 334             {
 335               einfo ("%X%P: can not size stub section: %E\n");
 336               return;
 337             }
 338
 339           toc_section = bfd_get_section_by_name (output_bfd, ".got");
 340           if (toc_section != NULL)
 341             lang_for_each_statement (build_toc_list);
 342
 343           ppc64_elf_reinit_toc (output_bfd, &link_info);
 344
 345           lang_for_each_statement (build_section_lists);
 346
 347           /* Call into the BFD backend to do the real work.  */
 348           if (!ppc64_elf_size_stubs (output_bfd,
 349                                      &link_info,
 350                                      group_size,
 351                                      &ppc_add_stub_section,
 352                                      &ppc_layout_sections_again))
 353             {
 354               einfo ("%X%P: can not size stub section: %E\n");
 355               return;
 356             }
 357         }
 358     }
 359
 360   if (need_laying_out)
 361     ppc_layout_sections_again ();
 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
 384
 385 /* Add a pattern matching ".foo" for every "foo" in a version script.
 386
 387    The reason for doing this is that many shared library version
 388    scripts export a selected set of functions or data symbols, forcing
 389    others local.  eg.
 390
 391    . VERS_1 {
 392    .       global:
 393    .               this; that; some; thing;
 394    .       local:
 395    .               *;
 396    .   };
 397
 398    To make the above work for PowerPC64, we need to export ".this",
 399    ".that" and so on, otherwise only the function descriptor syms are
 400    exported.  Lack of an exported function code sym may cause a
 401    definition to be pulled in from a static library.  */
 402
 403 static struct bfd_elf_version_expr *
 404 gld${EMULATION_NAME}_new_vers_pattern (struct bfd_elf_version_expr *entry)
 405 {
 406   struct bfd_elf_version_expr *dot_entry;
 407   unsigned int len;
 408   char *dot_pat;
 409
 410   if (!dotsyms || entry->pattern[0] == '*' || entry->pattern[0] == '.')
 411     return entry;
 412
 413   dot_entry = xmalloc (sizeof *dot_entry);
 414   *dot_entry = *entry;
 415   dot_entry->next = entry;
 416   len = strlen (entry->pattern) + 2;
 417   dot_pat = xmalloc (len);
 418   dot_pat[0] = '.';
 419   memcpy (dot_pat + 1, entry->pattern, len - 1);
 420   dot_entry->pattern = dot_pat;
 421   return dot_entry;
 422 }
 423
 424
 425 /* Avoid processing the fake stub_file in vercheck, stat_needed and
 426    check_needed routines.  */
 427
 428 static void (*real_func) (lang_input_statement_type *);
 429
 430 static void ppc_for_each_input_file_wrapper (lang_input_statement_type *l)
 431 {
 432   if (l != stub_file)
 433     (*real_func) (l);
 434 }
 435
 436 static void
 437 ppc_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
 438 {
 439   real_func = func;
 440   lang_for_each_input_file (&ppc_for_each_input_file_wrapper);
 441 }
 442
 443 #define lang_for_each_input_file ppc_lang_for_each_input_file
 444
 445 EOF
 446
 447 # Define some shell vars to insert bits of code into the standard elf
 448 # parse_args and list_options functions.
 449 #
 450 PARSE_AND_LIST_PROLOGUE='
 451 #define OPTION_STUBGROUP_SIZE           301
 452 #define OPTION_STUBSYMS                 (OPTION_STUBGROUP_SIZE + 1)
 453 #define OPTION_DOTSYMS                  (OPTION_STUBSYMS + 1)
 454 #define OPTION_NO_DOTSYMS               (OPTION_DOTSYMS + 1)
 455 #define OPTION_NO_TLS_OPT               (OPTION_NO_DOTSYMS + 1)
 456 '
 457
 458 PARSE_AND_LIST_LONGOPTS='
 459   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 460   { "emit-stub-syms", no_argument, NULL, OPTION_STUBSYMS },
 461   { "dotsyms", no_argument, NULL, OPTION_DOTSYMS },
 462   { "no-dotsyms", no_argument, NULL, OPTION_NO_DOTSYMS },
 463   { "no-tls-optimize", no_argument, NULL, OPTION_NO_TLS_OPT },
 464 '
 465
 466 PARSE_AND_LIST_OPTIONS='
 467   fprintf (file, _("\
 468   --stub-group-size=N   Maximum size of a group of input sections that can be\n\
 469                           handled by one stub section.  A negative value\n\
 470                           locates all stubs before their branches (with a\n\
 471                           group size of -N), while a positive value allows\n\
 472                           two groups of input sections, one before, and one\n\
 473                           after each stub section.  Values of +/-1 indicate\n\
 474                           the linker should choose suitable defaults.\n"
 475                    ));
 476   fprintf (file, _("\
 477   --emit-stub-syms      Label linker stubs with a symbol.\n"
 478                    ));
 479   fprintf (file, _("\
 480   --dotsyms             For every version pattern \"foo\" in a version script,\n\
 481                           add \".foo\" so that function code symbols are\n\
 482                           treated the same as function descriptor symbols.\n\
 483                           Defaults to on.\n"
 484                    ));
 485   fprintf (file, _("\
 486   --no-dotsyms          Don'\''t do anything special in version scripts.\n"
 487                    ));
 488   fprintf (file, _("\
 489   --no-tls-optimize     Don'\''t try to optimize TLS accesses.\n"
 490                    ));
 491 '
 492
 493 PARSE_AND_LIST_ARGS_CASES='
 494     case OPTION_STUBGROUP_SIZE:
 495       {
 496         const char *end;
 497         group_size = bfd_scan_vma (optarg, &end, 0);
 498         if (*end)
 499           einfo (_("%P%F: invalid number `%s'\''\n"), optarg);
 500       }
 501       break;
 502
 503     case OPTION_STUBSYMS:
 504       emit_stub_syms = 1;
 505       break;
 506
 507     case OPTION_DOTSYMS:
 508       dotsyms = 1;
 509       break;
 510
 511     case OPTION_NO_DOTSYMS:
 512       dotsyms = 0;
 513       break;
 514
 515     case OPTION_NO_TLS_OPT:
 516       notlsopt = 1;
 517       break;
 518 '
 519
 520 # Put these extra ppc64elf routines in ld_${EMULATION_NAME}_emulation
 521 #
 522 LDEMUL_AFTER_OPEN=ppc_after_open
 523 LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
 524 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 525 LDEMUL_FINISH=gld${EMULATION_NAME}_finish
 526 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_create_output_section_statements
 527 LDEMUL_NEW_VERS_PATTERN=gld${EMULATION_NAME}_new_vers_pattern