ld/emultempl/ppc64elf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright 2002 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${EMULATION_NAME}.c <<EOF
  25
  26 #include "ldctor.h"
  27 #include "libbfd.h"
  28 #include "elf64-ppc.h"
  29
  30 /* Fake input file for stubs.  */
  31 static lang_input_statement_type *stub_file;
  32
  33 /* Whether we need to call ppc_layout_sections_again.  */
  34 static int need_laying_out = 0;
  35
  36 /* Maximum size of a group of input sections that can be handled by
  37    one stub section.  A value of +/-1 indicates the bfd back-end
  38    should use a suitable default size.  */
  39 static bfd_signed_vma group_size = 1;
  40
  41 /* Whether to add ".foo" entries for each "foo" in a version script.  */
  42 static int dotsyms = 1;
  43
  44 static void ppc_create_output_section_statements PARAMS ((void));
  45 static asection *ppc_add_stub_section PARAMS ((const char *, asection *));
  46 static void ppc_layout_sections_again PARAMS ((void));
  47 static void gld${EMULATION_NAME}_after_allocation PARAMS ((void));
  48 static void build_section_lists PARAMS ((lang_statement_union_type *));
  49 static struct bfd_elf_version_expr *gld${EMULATION_NAME}_new_vers_pattern
  50   PARAMS ((struct bfd_elf_version_expr *));
  51
  52 /* This is called before the input files are opened.  We create a new
  53    fake input file to hold the stub sections.  */
  54
  55 static void
  56 ppc_create_output_section_statements ()
  57 {
  58   stub_file = lang_add_input_file ("linker stubs",
  59                                    lang_input_file_is_fake_enum,
  60                                    NULL);
  61   stub_file->the_bfd = bfd_create ("linker stubs", output_bfd);
  62   if (stub_file->the_bfd == NULL
  63       || !bfd_set_arch_mach (stub_file->the_bfd,
  64                              bfd_get_arch (output_bfd),
  65                              bfd_get_mach (output_bfd)))
  66     {
  67       einfo ("%X%P: can not create BFD %E\n");
  68       return;
  69     }
  70
  71   ldlang_add_file (stub_file);
  72 }
  73
  74
  75 struct hook_stub_info
  76 {
  77   lang_statement_list_type add;
  78   asection *input_section;
  79 };
  80
  81 /* Traverse the linker tree to find the spot where the stub goes.  */
  82
  83 static boolean hook_in_stub
  84   PARAMS ((struct hook_stub_info *, lang_statement_union_type **));
  85
  86 static boolean
  87 hook_in_stub (info, lp)
  88      struct hook_stub_info *info;
  89      lang_statement_union_type **lp;
  90 {
  91   lang_statement_union_type *l;
  92   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                  before its associated input section.  */
 128               *lp = info->add.head;
 129               *(info->add.tail) = l;
 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 ppc64_elf_size_stubs.  */
 156
 157 /* Create a new stub section, and arrange for it to be linked
 158    immediately before INPUT_SECTION.  */
 159
 160 static asection *
 161 ppc_add_stub_section (stub_sec_name, input_section)
 162      const char *stub_sec_name;
 163      asection *input_section;
 164 {
 165   asection *stub_sec;
 166   flagword flags;
 167   asection *output_section;
 168   const char *secname;
 169   lang_output_section_statement_type *os;
 170   struct hook_stub_info info;
 171
 172   stub_sec = bfd_make_section_anyway (stub_file->the_bfd, stub_sec_name);
 173   if (stub_sec == NULL)
 174     goto err_ret;
 175
 176   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 177            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 178   if (!bfd_set_section_flags (stub_file->the_bfd, stub_sec, flags))
 179     goto err_ret;
 180
 181   output_section = input_section->output_section;
 182   secname = bfd_get_section_name (output_section->owner, output_section);
 183   os = lang_output_section_find (secname);
 184
 185   info.input_section = input_section;
 186   lang_list_init (&info.add);
 187   lang_add_section (&info.add, stub_sec, os, stub_file);
 188
 189   if (info.add.head == NULL)
 190     goto err_ret;
 191
 192   if (hook_in_stub (&info, &os->children.head))
 193     return stub_sec;
 194
 195  err_ret:
 196   einfo ("%X%P: can not make stub section: %E\n");
 197   return NULL;
 198 }
 199
 200
 201 /* Another call-back for ppc64_elf_size_stubs.  */
 202
 203 static void
 204 ppc_layout_sections_again ()
 205 {
 206   /* If we have changed sizes of the stub sections, then we need
 207      to recalculate all the section offsets.  This may mean we need to
 208      add even more stubs.  */
 209   need_laying_out = 0;
 210
 211   lang_reset_memory_regions ();
 212
 213   /* Resize the sections.  */
 214   lang_size_sections (stat_ptr->head, abs_output_section,
 215                       &stat_ptr->head, 0, (bfd_vma) 0, NULL);
 216
 217   /* Recalculate TOC base.  */
 218   ldemul_after_allocation ();
 219
 220   /* Do the assignments again.  */
 221   lang_do_assignments (stat_ptr->head, abs_output_section,
 222                        (fill_type *) 0, (bfd_vma) 0);
 223 }
 224
 225
 226 /* Call the back-end function to set TOC base after we have placed all
 227    the sections.  */
 228 static void
 229 gld${EMULATION_NAME}_after_allocation ()
 230 {
 231   if (!link_info.relocateable)
 232     _bfd_set_gp_value (output_bfd, ppc64_elf_toc (output_bfd));
 233 }
 234
 235
 236 static void
 237 build_section_lists (statement)
 238      lang_statement_union_type *statement;
 239 {
 240   if (statement->header.type == lang_input_section_enum
 241       && !statement->input_section.ifile->just_syms_flag
 242       && statement->input_section.section->output_section != NULL
 243       && statement->input_section.section->output_section->owner == output_bfd)
 244     {
 245       ppc64_elf_next_input_section (&link_info,
 246                                     statement->input_section.section);
 247     }
 248 }
 249
 250
 251 /* Final emulation specific call.  */
 252
 253 static void
 254 gld${EMULATION_NAME}_finish ()
 255 {
 256   int ret;
 257
 258   /* e_entry on PowerPC64 points to the function descriptor for
 259      _start.  If _start is missing, default to the first function
 260      descriptor in the .opd section.  */
 261   entry_section = ".opd";
 262
 263   /* If generating a relocatable output file, then we don't have any
 264      stubs.  */
 265   if (link_info.relocateable)
 266     return;
 267
 268   /* bfd_elf64_discard_info just plays with debugging sections,
 269      ie. doesn't affect any code, so we can delay resizing the
 270      sections.  It's likely we'll resize everything in the process of
 271      adding stubs.  */
 272   if (bfd_elf${ELFSIZE}_discard_info (output_bfd, &link_info))
 273     need_laying_out = 1;
 274
 275   ret = ppc64_elf_setup_section_lists (output_bfd, &link_info);
 276   if (ret != 0)
 277     {
 278       if (ret < 0)
 279         {
 280           einfo ("%X%P: can not size stub section: %E\n");
 281           return;
 282         }
 283
 284       lang_for_each_statement (build_section_lists);
 285
 286       /* Call into the BFD backend to do the real work.  */
 287       if (!ppc64_elf_size_stubs (output_bfd,
 288                                  stub_file->the_bfd,
 289                                  &link_info,
 290                                  group_size,
 291                                  &ppc_add_stub_section,
 292                                  &ppc_layout_sections_again))
 293         {
 294           einfo ("%X%P: can not size stub section: %E\n");
 295           return;
 296         }
 297     }
 298
 299   if (need_laying_out)
 300     ppc_layout_sections_again ();
 301
 302   if (stub_file->the_bfd->sections != NULL)
 303     {
 304       if (!ppc64_elf_build_stubs (&link_info))
 305         einfo ("%X%P: can not build stubs: %E\n");
 306     }
 307 }
 308
 309
 310 /* Add a pattern matching ".foo" for every "foo" in a version script.
 311
 312    The reason for doing this is that many shared library version
 313    scripts export a selected set of functions or data symbols, forcing
 314    others local.  eg.
 315
 316    . VERS_1 {
 317    .       global:
 318    .               this; that; some; thing;
 319    .       local:
 320    .               *;
 321    .   };
 322
 323    To make the above work for PowerPC64, we need to export ".this",
 324    ".that" and so on, otherwise only the function descriptor syms are
 325    exported.  Lack of an exported function code sym may cause a
 326    definition to be pulled in from a static library.  */
 327
 328 struct bfd_elf_version_expr *
 329 gld${EMULATION_NAME}_new_vers_pattern (entry)
 330      struct bfd_elf_version_expr *entry;
 331 {
 332   struct bfd_elf_version_expr *dot_entry;
 333   struct bfd_elf_version_expr *next;
 334   unsigned int len;
 335   char *dot_pat;
 336
 337   if (!dotsyms || entry->pattern[0] == '*')
 338     return entry;
 339
 340   /* Is the script adding ".foo" explicitly?  */
 341   if (entry->pattern[0] == '.')
 342     {
 343       /* We may have added this pattern automatically.  Don't add it
 344          again.  Quadratic behaviour here is acceptable as the list
 345          may be traversed for each input bfd symbol.  */
 346       for (next = entry->next; next != NULL; next = next->next)
 347         {
 348           if (strcmp (next->pattern, entry->pattern) == 0
 349               && next->match == entry->match)
 350             {
 351               next = entry->next;
 352               free (entry->pattern);
 353               free (entry);
 354               return next;
 355             }
 356         }
 357       return entry;
 358     }
 359
 360   /* Don't add ".foo" if the script has already done so.  */
 361   for (next = entry->next; next != NULL; next = next->next)
 362     {
 363       if (next->pattern[0] == '.'
 364           && strcmp (next->pattern + 1, entry->pattern) == 0
 365           && next->match == entry->match)
 366         return entry;
 367     }
 368
 369   dot_entry = (struct bfd_elf_version_expr *) xmalloc (sizeof *dot_entry);
 370   dot_entry->next = entry;
 371   len = strlen (entry->pattern) + 2;
 372   dot_pat = xmalloc (len);
 373   dot_pat[0] = '.';
 374   memcpy (dot_pat + 1, entry->pattern, len - 1);
 375   dot_entry->pattern = dot_pat;
 376   dot_entry->match = entry->match;
 377   return dot_entry;
 378 }
 379
 380
 381 /* Avoid processing the fake stub_file in vercheck, stat_needed and
 382    check_needed routines.  */
 383
 384 static void ppc_for_each_input_file_wrapper
 385   PARAMS ((lang_input_statement_type *));
 386 static void ppc_lang_for_each_input_file
 387   PARAMS ((void (*) (lang_input_statement_type *)));
 388
 389 static void (*real_func) PARAMS ((lang_input_statement_type *));
 390
 391 static void ppc_for_each_input_file_wrapper (l)
 392      lang_input_statement_type *l;
 393 {
 394   if (l != stub_file)
 395     (*real_func) (l);
 396 }
 397
 398 static void
 399 ppc_lang_for_each_input_file (func)
 400      void (*func) PARAMS ((lang_input_statement_type *));
 401 {
 402   real_func = func;
 403   lang_for_each_input_file (&ppc_for_each_input_file_wrapper);
 404 }
 405
 406 #define lang_for_each_input_file ppc_lang_for_each_input_file
 407
 408 EOF
 409
 410 # Define some shell vars to insert bits of code into the standard elf
 411 # parse_args and list_options functions.
 412 #
 413 PARSE_AND_LIST_PROLOGUE='
 414 #define OPTION_STUBGROUP_SIZE           301
 415 #define OPTION_DOTSYMS                  (OPTION_STUBGROUP_SIZE + 1)
 416 #define OPTION_NO_DOTSYMS               (OPTION_DOTSYMS + 1)
 417 '
 418
 419 # The options are repeated below so that no abbreviations are allowed.
 420 # Otherwise -s matches stub-group-size
 421 PARSE_AND_LIST_LONGOPTS='
 422   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 423   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 424   { "dotsyms", no_argument, NULL, OPTION_DOTSYMS },
 425   { "dotsyms", no_argument, NULL, OPTION_DOTSYMS },
 426   { "no-dotsyms", no_argument, NULL, OPTION_NO_DOTSYMS },
 427   { "no-dotsyms", no_argument, NULL, OPTION_NO_DOTSYMS },
 428 '
 429
 430 PARSE_AND_LIST_OPTIONS='
 431   fprintf (file, _("\
 432   --stub-group-size=N   Maximum size of a group of input sections that can be\n\
 433                           handled by one stub section.  A negative value\n\
 434                           locates all stubs before their branches (with a\n\
 435                           group size of -N), while a positive value allows\n\
 436                           two groups of input sections, one before, and one\n\
 437                           after each stub section.  Values of +/-1 indicate\n\
 438                           the linker should choose suitable defaults.\n"
 439                    ));
 440   fprintf (file, _("\
 441   --dotsyms             For every version pattern \"foo\" in a version script,\n\
 442                           add \".foo\" so that function code symbols are\n\
 443                           treated the same as function descriptor symbols.\n\
 444                           Defaults to on.\n"
 445                    ));
 446   fprintf (file, _("\
 447   --no-dotsyms          Don'\''t do anything special in version scripts.\n"
 448                    ));
 449 '
 450
 451 PARSE_AND_LIST_ARGS_CASES='
 452     case OPTION_STUBGROUP_SIZE:
 453       {
 454         const char *end;
 455         group_size = bfd_scan_vma (optarg, &end, 0);
 456         if (*end)
 457           einfo (_("%P%F: invalid number `%s'\''\n"), optarg);
 458       }
 459       break;
 460
 461     case OPTION_DOTSYMS:
 462       {
 463         dotsyms = 1;
 464       }
 465       break;
 466
 467     case OPTION_NO_DOTSYMS:
 468       {
 469         dotsyms = 0;
 470       }
 471       break;
 472 '
 473
 474 # Put these extra ppc64elf routines in ld_${EMULATION_NAME}_emulation
 475 #
 476 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 477 LDEMUL_FINISH=gld${EMULATION_NAME}_finish
 478 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_create_output_section_statements
 479 LDEMUL_NEW_VERS_PATTERN=gld${EMULATION_NAME}_new_vers_pattern