ld/emultempl/aarch64elf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2009-2018 Free Software Foundation, Inc.
   3 #   Contributed by ARM Ltd.
   4 #
   5 # This file is part of the GNU Binutils.
   6 #
   7 # This program is free software; you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation; either version 3 of the license, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program; see the file COPYING3. If not,
  19 # see <http://www.gnu.org/licenses/>.
  20 #
  21
  22 # This file is sourced from elf32.em, and defines extra aarch64-elf
  23 # specific routines.
  24 #
  25 fragment <<EOF
  26
  27 #include "ldctor.h"
  28 #include "elf/aarch64.h"
  29
  30 static int no_enum_size_warning = 0;
  31 static int no_wchar_size_warning = 0;
  32 static int pic_veneer = 0;
  33 static int fix_erratum_835769 = 0;
  34 static int fix_erratum_843419 = 0;
  35 static int no_apply_dynamic_relocs = 0;
  36
  37 static void
  38 gld${EMULATION_NAME}_before_parse (void)
  39 {
  40 #ifndef TARGET_                 /* I.e., if not generic.  */
  41   ldfile_set_output_arch ("`echo ${ARCH}`", bfd_arch_unknown);
  42 #endif /* not TARGET_ */
  43   input_flags.dynamic = ${DYNAMIC_LINK-TRUE};
  44   config.has_shared = `if test -n "$GENERATE_SHLIB_SCRIPT" ; then echo TRUE ; else echo FALSE ; fi`;
  45   config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then echo TRUE ; else echo FALSE ; fi`;
  46   link_info.check_relocs_after_open_input = TRUE;
  47   link_info.relro = DEFAULT_LD_Z_RELRO;
  48 }
  49
  50 static void
  51 aarch64_elf_before_allocation (void)
  52 {
  53   /* We should be able to set the size of the interworking stub section.  We
  54      can't do it until later if we have dynamic sections, though.  */
  55   if (! elf_hash_table (&link_info)->dynamic_sections_created)
  56     {
  57       /* Here we rummage through the found bfds to collect information.  */
  58       LANG_FOR_EACH_INPUT_STATEMENT (is)
  59       {
  60         /* Initialise mapping tables for code/data.  */
  61         bfd_elf${ELFSIZE}_aarch64_init_maps (is->the_bfd);
  62       }
  63     }
  64
  65   /* Call the standard elf routine.  */
  66   gld${EMULATION_NAME}_before_allocation ();
  67 }
  68
  69 /* Fake input file for stubs.  */
  70 static lang_input_statement_type *stub_file;
  71
  72 /* Whether we need to call gldarm_layout_sections_again.  */
  73 static int need_laying_out = 0;
  74
  75 /* Maximum size of a group of input sections that can be handled by
  76    one stub section.  A value of +/-1 indicates the bfd back-end
  77    should use a suitable default size.  */
  78 static bfd_signed_vma group_size = 1;
  79
  80 struct hook_stub_info
  81 {
  82   lang_statement_list_type add;
  83   asection *input_section;
  84 };
  85
  86 /* Traverse the linker tree to find the spot where the stub goes.  */
  87
  88 static bfd_boolean
  89 hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp)
  90 {
  91   lang_statement_union_type *l;
  92   bfd_boolean ret;
  93
  94   for (; (l = *lp) != NULL; lp = &l->header.next)
  95     {
  96       switch (l->header.type)
  97         {
  98         case lang_constructors_statement_enum:
  99           ret = hook_in_stub (info, &constructor_list.head);
 100           if (ret)
 101             return ret;
 102           break;
 103
 104         case lang_output_section_statement_enum:
 105           ret = hook_in_stub (info,
 106                               &l->output_section_statement.children.head);
 107           if (ret)
 108             return ret;
 109           break;
 110
 111         case lang_wild_statement_enum:
 112           ret = hook_in_stub (info, &l->wild_statement.children.head);
 113           if (ret)
 114             return ret;
 115           break;
 116
 117         case lang_group_statement_enum:
 118           ret = hook_in_stub (info, &l->group_statement.children.head);
 119           if (ret)
 120             return ret;
 121           break;
 122
 123         case lang_input_section_enum:
 124           if (l->input_section.section == info->input_section)
 125             {
 126               /* We've found our section.  Insert the stub immediately
 127                  after its associated input section.  */
 128               *(info->add.tail) = l->header.next;
 129               l->header.next = info->add.head;
 130               return TRUE;
 131             }
 132           break;
 133
 134         case lang_data_statement_enum:
 135         case lang_reloc_statement_enum:
 136         case lang_object_symbols_statement_enum:
 137         case lang_output_statement_enum:
 138         case lang_target_statement_enum:
 139         case lang_input_statement_enum:
 140         case lang_assignment_statement_enum:
 141         case lang_padding_statement_enum:
 142         case lang_address_statement_enum:
 143         case lang_fill_statement_enum:
 144           break;
 145
 146         default:
 147           FAIL ();
 148           break;
 149         }
 150     }
 151   return FALSE;
 152 }
 153
 154
 155 /* Call-back for elf${ELFSIZE}_aarch64_size_stubs.  */
 156
 157 /* Create a new stub section, and arrange for it to be linked
 158    immediately after INPUT_SECTION.  */
 159
 160 static asection *
 161 elf${ELFSIZE}_aarch64_add_stub_section (const char *stub_sec_name,
 162                                         asection *input_section)
 163 {
 164   asection *stub_sec;
 165   flagword flags;
 166   asection *output_section;
 167   lang_output_section_statement_type *os;
 168   struct hook_stub_info info;
 169
 170   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 171            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 172   stub_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
 173                                                  stub_sec_name, flags);
 174   if (stub_sec == NULL)
 175     goto err_ret;
 176
 177   /* Long branch stubs contain a 64-bit address, so the section requires
 178      8 byte alignment.  */
 179   bfd_set_section_alignment (stub_file->the_bfd, stub_sec, 3);
 180
 181   output_section = input_section->output_section;
 182   os = lang_output_section_get (output_section);
 183
 184   info.input_section = input_section;
 185   lang_list_init (&info.add);
 186   lang_add_section (&info.add, stub_sec, NULL, os);
 187
 188   if (info.add.head == NULL)
 189     goto err_ret;
 190
 191   if (hook_in_stub (&info, &os->children.head))
 192     return stub_sec;
 193
 194  err_ret:
 195   einfo (_("%X%P: can not make stub section: %E\n"));
 196   return NULL;
 197 }
 198
 199 /* Another call-back for elf${ELFSIZE}_aarch64_size_stubs.  */
 200
 201 static void
 202 gldaarch64_layout_sections_again (void)
 203 {
 204   /* If we have changed sizes of the stub sections, then we need
 205      to recalculate all the section offsets.  This may mean we need to
 206      add even more stubs.  */
 207   gld${EMULATION_NAME}_map_segments (TRUE);
 208   need_laying_out = -1;
 209 }
 210
 211 static void
 212 build_section_lists (lang_statement_union_type *statement)
 213 {
 214   if (statement->header.type == lang_input_section_enum)
 215     {
 216       asection *i = statement->input_section.section;
 217
 218       if (!((lang_input_statement_type *) i->owner->usrdata)->flags.just_syms
 219           && (i->flags & SEC_EXCLUDE) == 0
 220           && i->output_section != NULL
 221           && i->output_section->owner == link_info.output_bfd)
 222         elf${ELFSIZE}_aarch64_next_input_section (& link_info, i);
 223     }
 224 }
 225
 226 static void
 227 gld${EMULATION_NAME}_after_allocation (void)
 228 {
 229   int ret;
 230
 231   /* bfd_elf32_discard_info just plays with debugging sections,
 232      ie. doesn't affect any code, so we can delay resizing the
 233      sections.  It's likely we'll resize everything in the process of
 234      adding stubs.  */
 235   ret = bfd_elf_discard_info (link_info.output_bfd, & link_info);
 236   if (ret < 0)
 237     {
 238       einfo (_("%X%P: .eh_frame/.stab edit: %E\n"));
 239       return;
 240     }
 241   else if (ret > 0)
 242     need_laying_out = 1;
 243
 244   /* If generating a relocatable output file, then we don't
 245      have to examine the relocs.  */
 246   if (stub_file != NULL && !bfd_link_relocatable (&link_info))
 247     {
 248       ret = elf${ELFSIZE}_aarch64_setup_section_lists (link_info.output_bfd,
 249                                                        &link_info);
 250       if (ret != 0)
 251         {
 252           if (ret < 0)
 253             {
 254               einfo (_("%X%P: could not compute sections lists "
 255                        "for stub generation: %E\n"));
 256               return;
 257             }
 258
 259           lang_for_each_statement (build_section_lists);
 260
 261           /* Call into the BFD backend to do the real work.  */
 262           if (! elf${ELFSIZE}_aarch64_size_stubs (link_info.output_bfd,
 263                                           stub_file->the_bfd,
 264                                           & link_info,
 265                                           group_size,
 266                                           & elf${ELFSIZE}_aarch64_add_stub_section,
 267                                           & gldaarch64_layout_sections_again))
 268             {
 269               einfo (_("%X%P: can not size stub section: %E\n"));
 270               return;
 271             }
 272         }
 273     }
 274
 275   if (need_laying_out != -1)
 276     gld${EMULATION_NAME}_map_segments (need_laying_out);
 277 }
 278
 279 static void
 280 gld${EMULATION_NAME}_finish (void)
 281 {
 282   if (!bfd_link_relocatable (&link_info))
 283     {
 284       /* Now build the linker stubs.  */
 285       if (stub_file->the_bfd->sections != NULL)
 286         {
 287           if (! elf${ELFSIZE}_aarch64_build_stubs (& link_info))
 288             einfo (_("%X%P: can not build stubs: %E\n"));
 289         }
 290     }
 291
 292   finish_default ();
 293 }
 294
 295 /* This is a convenient point to tell BFD about target specific flags.
 296    After the output has been created, but before inputs are read.  */
 297 static void
 298 aarch64_elf_create_output_section_statements (void)
 299 {
 300   if (strstr (bfd_get_target (link_info.output_bfd), "aarch64") == NULL)
 301     {
 302       /* The arm backend needs special fields in the output hash structure.
 303          These will only be created if the output format is an arm format,
 304          hence we do not support linking and changing output formats at the
 305          same time.  Use a link followed by objcopy to change output formats.  */
 306       einfo (_("%F%P: error: cannot change output format "
 307                "whilst linking %s binaries\n"), "AArch64");
 308       return;
 309     }
 310
 311   bfd_elf${ELFSIZE}_aarch64_set_options (link_info.output_bfd, &link_info,
 312                                  no_enum_size_warning,
 313                                  no_wchar_size_warning,
 314                                  pic_veneer,
 315                                  fix_erratum_835769, fix_erratum_843419,
 316                                  no_apply_dynamic_relocs);
 317
 318   stub_file = lang_add_input_file ("linker stubs",
 319                                    lang_input_file_is_fake_enum,
 320                                    NULL);
 321   stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
 322   if (stub_file->the_bfd == NULL
 323       || ! bfd_set_arch_mach (stub_file->the_bfd,
 324                               bfd_get_arch (link_info.output_bfd),
 325                               bfd_get_mach (link_info.output_bfd)))
 326     {
 327       einfo (_("%F%P: can not create BFD: %E\n"));
 328       return;
 329     }
 330
 331   stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
 332   ldlang_add_file (stub_file);
 333 }
 334
 335 /* Avoid processing the fake stub_file in vercheck, stat_needed and
 336    check_needed routines.  */
 337
 338 static void (*real_func) (lang_input_statement_type *);
 339
 340 static void aarch64_for_each_input_file_wrapper (lang_input_statement_type *l)
 341 {
 342   if (l != stub_file)
 343     (*real_func) (l);
 344 }
 345
 346 static void
 347 aarch64_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
 348 {
 349   real_func = func;
 350   lang_for_each_input_file (&aarch64_for_each_input_file_wrapper);
 351 }
 352
 353 #define lang_for_each_input_file aarch64_lang_for_each_input_file
 354
 355 EOF
 356
 357 # Define some shell vars to insert bits of code into the standard elf
 358 # parse_args and list_options functions.
 359 #
 360 PARSE_AND_LIST_PROLOGUE='
 361 #define OPTION_NO_ENUM_SIZE_WARNING     309
 362 #define OPTION_PIC_VENEER               310
 363 #define OPTION_STUBGROUP_SIZE           311
 364 #define OPTION_NO_WCHAR_SIZE_WARNING    312
 365 #define OPTION_FIX_ERRATUM_835769       313
 366 #define OPTION_FIX_ERRATUM_843419       314
 367 #define OPTION_NO_APPLY_DYNAMIC_RELOCS  315
 368 '
 369
 370 PARSE_AND_LIST_SHORTOPTS=p
 371
 372 PARSE_AND_LIST_LONGOPTS='
 373   { "no-pipeline-knowledge", no_argument, NULL, '\'p\''},
 374   { "no-enum-size-warning", no_argument, NULL, OPTION_NO_ENUM_SIZE_WARNING},
 375   { "pic-veneer", no_argument, NULL, OPTION_PIC_VENEER},
 376   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 377   { "no-wchar-size-warning", no_argument, NULL, OPTION_NO_WCHAR_SIZE_WARNING},
 378   { "fix-cortex-a53-835769", no_argument, NULL, OPTION_FIX_ERRATUM_835769},
 379   { "fix-cortex-a53-843419", no_argument, NULL, OPTION_FIX_ERRATUM_843419},
 380   { "no-apply-dynamic-relocs", no_argument, NULL, OPTION_NO_APPLY_DYNAMIC_RELOCS},
 381 '
 382
 383 PARSE_AND_LIST_OPTIONS='
 384   fprintf (file, _("  --no-enum-size-warning      Don'\''t warn about objects with incompatible\n"
 385                    "                                enum sizes\n"));
 386   fprintf (file, _("  --no-wchar-size-warning     Don'\''t warn about objects with incompatible\n"
 387                    "                                wchar_t sizes\n"));
 388   fprintf (file, _("  --pic-veneer                Always generate PIC interworking veneers\n"));
 389   fprintf (file, _("\
 390   --stub-group-size=N         Maximum size of a group of input sections that\n\
 391                                 can be handled by one stub section.  A negative\n\
 392                                 value locates all stubs after their branches\n\
 393                                 (with a group size of -N), while a positive\n\
 394                                 value allows two groups of input sections, one\n\
 395                                 before, and one after each stub section.\n\
 396                                 Values of +/-1 indicate the linker should\n\
 397                                 choose suitable defaults.\n"));
 398   fprintf (file, _("  --fix-cortex-a53-835769      Fix erratum 835769\n"));
 399   fprintf (file, _("  --fix-cortex-a53-843419      Fix erratum 843419\n"));
 400   fprintf (file, _("  --no-apply-dynamic-relocs    Do not apply link-time values for dynamic relocations\n"));
 401 '
 402
 403 PARSE_AND_LIST_ARGS_CASES='
 404     case '\'p\'':
 405       /* Only here for backwards compatibility.  */
 406       break;
 407
 408     case OPTION_NO_ENUM_SIZE_WARNING:
 409       no_enum_size_warning = 1;
 410       break;
 411
 412     case OPTION_NO_WCHAR_SIZE_WARNING:
 413       no_wchar_size_warning = 1;
 414       break;
 415
 416     case OPTION_PIC_VENEER:
 417       pic_veneer = 1;
 418       break;
 419
 420     case OPTION_FIX_ERRATUM_835769:
 421       fix_erratum_835769 = 1;
 422       break;
 423
 424     case OPTION_FIX_ERRATUM_843419:
 425       fix_erratum_843419 = 1;
 426       break;
 427
 428     case OPTION_NO_APPLY_DYNAMIC_RELOCS:
 429       no_apply_dynamic_relocs = 1;
 430       break;
 431
 432     case OPTION_STUBGROUP_SIZE:
 433       {
 434         const char *end;
 435
 436         group_size = bfd_scan_vma (optarg, &end, 0);
 437         if (*end)
 438           einfo (_("%F%P: invalid number `%s'\''\n"), optarg);
 439       }
 440       break;
 441 '
 442
 443 # We have our own before_allocation etc. functions, but they call
 444 # the standard routines, so give them a different name.
 445 LDEMUL_BEFORE_ALLOCATION=aarch64_elf_before_allocation
 446 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 447 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=aarch64_elf_create_output_section_statements
 448
 449 # Replace the elf before_parse function with our own.
 450 LDEMUL_BEFORE_PARSE=gld"${EMULATION_NAME}"_before_parse
 451
 452 # Call the extra arm-elf function
 453 LDEMUL_FINISH=gld${EMULATION_NAME}_finish