ld/emultempl/metagelf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright 2013 Free Software Foundation, Inc.
   3 #
   4 # This file is part of GNU Binutils.
   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 3 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., 51 Franklin Street - Fifth Floor, Boston,
  19 # MA 02110-1301, USA.
  20 #
  21
  22 # This file is sourced from elf32.em, and defines extra metagelf
  23 # specific routines. Taken from hppaelf.em.
  24 #
  25 fragment <<EOF
  26
  27 #include "ldctor.h"
  28 #include "elf32-metag.h"
  29
  30
  31 /* Fake input file for stubs.  */
  32 static lang_input_statement_type *stub_file;
  33
  34 /* Whether we need to call metag_layout_sections_again.  */
  35 static int need_laying_out = 0;
  36
  37 /* Maximum size of a group of input sections that can be handled by
  38    one stub section.  A value of +/-1 indicates the bfd back-end
  39    should use a suitable default size.  */
  40 static bfd_signed_vma group_size = 1;
  41
  42 /* This is called before the input files are opened.  We create a new
  43    fake input file to hold the stub sections.  */
  44
  45 static void
  46 metagelf_create_output_section_statements (void)
  47 {
  48   extern const bfd_target bfd_elf32_metag_vec;
  49
  50   if (link_info.output_bfd->xvec != &bfd_elf32_metag_vec)
  51     return;
  52
  53   stub_file = lang_add_input_file ("linker stubs",
  54                                    lang_input_file_is_fake_enum,
  55                                    NULL);
  56   stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
  57   if (stub_file->the_bfd == NULL
  58       || ! bfd_set_arch_mach (stub_file->the_bfd,
  59                               bfd_get_arch (link_info.output_bfd),
  60                               bfd_get_mach (link_info.output_bfd)))
  61     {
  62       einfo ("%X%P: can not create BFD %E\n");
  63       return;
  64     }
  65
  66   stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
  67   ldlang_add_file (stub_file);
  68 }
  69
  70
  71 struct hook_stub_info
  72 {
  73   lang_statement_list_type add;
  74   asection *input_section;
  75 };
  76
  77 /* Traverse the linker tree to find the spot where the stub goes.  */
  78
  79 static bfd_boolean
  80 hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp)
  81 {
  82   lang_statement_union_type *l;
  83   bfd_boolean ret;
  84
  85   for (; (l = *lp) != NULL; lp = &l->header.next)
  86     {
  87       switch (l->header.type)
  88         {
  89         case lang_constructors_statement_enum:
  90           ret = hook_in_stub (info, &constructor_list.head);
  91           if (ret)
  92             return ret;
  93           break;
  94
  95         case lang_output_section_statement_enum:
  96           ret = hook_in_stub (info,
  97                               &l->output_section_statement.children.head);
  98           if (ret)
  99             return ret;
 100           break;
 101
 102         case lang_wild_statement_enum:
 103           ret = hook_in_stub (info, &l->wild_statement.children.head);
 104           if (ret)
 105             return ret;
 106           break;
 107
 108         case lang_group_statement_enum:
 109           ret = hook_in_stub (info, &l->group_statement.children.head);
 110           if (ret)
 111             return ret;
 112           break;
 113
 114         case lang_input_section_enum:
 115           if (l->input_section.section == info->input_section)
 116             {
 117               /* We've found our section.  Insert the stub immediately
 118                  before its associated input section.  */
 119               *lp = info->add.head;
 120               *(info->add.tail) = l;
 121               return TRUE;
 122             }
 123           break;
 124
 125         case lang_data_statement_enum:
 126         case lang_reloc_statement_enum:
 127         case lang_object_symbols_statement_enum:
 128         case lang_output_statement_enum:
 129         case lang_target_statement_enum:
 130         case lang_input_statement_enum:
 131         case lang_assignment_statement_enum:
 132         case lang_padding_statement_enum:
 133         case lang_address_statement_enum:
 134         case lang_fill_statement_enum:
 135           break;
 136
 137         default:
 138           FAIL ();
 139           break;
 140         }
 141     }
 142   return FALSE;
 143 }
 144
 145
 146 /* Call-back for elf_metag_size_stubs.  */
 147
 148 /* Create a new stub section, and arrange for it to be linked
 149    immediately before INPUT_SECTION.  */
 150
 151 static asection *
 152 metagelf_add_stub_section (const char *stub_sec_name, asection *input_section)
 153 {
 154   asection *stub_sec;
 155   flagword flags;
 156   asection *output_section;
 157   const char *secname;
 158   lang_output_section_statement_type *os;
 159   struct hook_stub_info info;
 160
 161   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 162            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 163   stub_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
 164                                                  stub_sec_name, flags);
 165   if (stub_sec == NULL)
 166     goto err_ret;
 167
 168   output_section = input_section->output_section;
 169   secname = bfd_get_section_name (output_section->owner, output_section);
 170   os = lang_output_section_find (secname);
 171
 172   info.input_section = input_section;
 173   lang_list_init (&info.add);
 174   lang_add_section (&info.add, stub_sec, NULL, os);
 175
 176   if (info.add.head == NULL)
 177     goto err_ret;
 178
 179   if (hook_in_stub (&info, &os->children.head))
 180     return stub_sec;
 181
 182  err_ret:
 183   einfo ("%X%P: can not make stub section: %E\n");
 184   return NULL;
 185 }
 186
 187
 188 /* Another call-back for elf_metag_size_stubs.  */
 189
 190 static void
 191 metagelf_layout_sections_again (void)
 192 {
 193   /* If we have changed sizes of the stub sections, then we need
 194      to recalculate all the section offsets.  This may mean we need to
 195      add even more stubs.  */
 196   gld${EMULATION_NAME}_map_segments (TRUE);
 197   need_laying_out = -1;
 198 }
 199
 200
 201 static void
 202 build_section_lists (lang_statement_union_type *statement)
 203 {
 204   if (statement->header.type == lang_input_section_enum)
 205     {
 206       asection *i = statement->input_section.section;
 207
 208       if (!((lang_input_statement_type *) i->owner->usrdata)->flags.just_syms
 209           && (i->flags & SEC_EXCLUDE) == 0
 210           && i->output_section != NULL
 211           && i->output_section->owner == link_info.output_bfd)
 212         {
 213           elf_metag_next_input_section (&link_info, i);
 214         }
 215     }
 216 }
 217
 218
 219 /* For Meta we use this opportunity to build linker stubs.  */
 220
 221 static void
 222 gld${EMULATION_NAME}_after_allocation (void)
 223 {
 224   /* bfd_elf_discard_info just plays with data and debugging sections,
 225      ie. doesn't affect code size, so we can delay resizing the
 226      sections.  It's likely we'll resize everything in the process of
 227      adding stubs.  */
 228   if (bfd_elf_discard_info (link_info.output_bfd, &link_info))
 229     need_laying_out = 1;
 230
 231   /* If generating a relocatable output file, then we don't
 232      have to examine the relocs.  */
 233   if (stub_file != NULL && !link_info.relocatable)
 234     {
 235       int ret = elf_metag_setup_section_lists (link_info.output_bfd,
 236                                                &link_info);
 237
 238       if (ret != 0)
 239         {
 240           if (ret < 0)
 241             {
 242               einfo ("%X%P: can not size stub section: %E\n");
 243               return;
 244             }
 245
 246           lang_for_each_statement (build_section_lists);
 247
 248           /* Call into the BFD backend to do the real work.  */
 249           if (! elf_metag_size_stubs (link_info.output_bfd,
 250                                       stub_file->the_bfd,
 251                                       &link_info,
 252                                       group_size,
 253                                       &metagelf_add_stub_section,
 254                                       &metagelf_layout_sections_again))
 255             {
 256               einfo ("%X%P: can not size stub section: %E\n");
 257               return;
 258             }
 259         }
 260     }
 261
 262   if (need_laying_out != -1)
 263     gld${EMULATION_NAME}_map_segments (need_laying_out);
 264
 265   if (! link_info.relocatable)
 266     {
 267       /* Now build the linker stubs.  */
 268       if (stub_file != NULL && stub_file->the_bfd->sections != NULL)
 269         {
 270           if (! elf_metag_build_stubs (&link_info))
 271             einfo ("%X%P: can not build stubs: %E\n");
 272         }
 273     }
 274 }
 275
 276
 277 /* Avoid processing the fake stub_file in vercheck, stat_needed and
 278    check_needed routines.  */
 279
 280 static void (*real_func) (lang_input_statement_type *);
 281
 282 static void metag_for_each_input_file_wrapper (lang_input_statement_type *l)
 283 {
 284   if (l != stub_file)
 285     (*real_func) (l);
 286 }
 287
 288 static void
 289 metag_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
 290 {
 291   real_func = func;
 292   lang_for_each_input_file (&metag_for_each_input_file_wrapper);
 293 }
 294
 295 #define lang_for_each_input_file metag_lang_for_each_input_file
 296
 297 EOF
 298
 299 # Define some shell vars to insert bits of code into the standard elf
 300 # parse_args and list_options functions.
 301 #
 302 PARSE_AND_LIST_PROLOGUE='
 303 #define OPTION_STUBGROUP_SIZE           301
 304 '
 305
 306 PARSE_AND_LIST_LONGOPTS='
 307   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 308 '
 309
 310 PARSE_AND_LIST_OPTIONS='
 311   fprintf (file, _("\
 312   --stub-group-size=N         Maximum size of a group of input sections that\n\
 313                                 can be handled by one stub section.  A negative\n\
 314                                 value locates all stubs before their branches\n\
 315                                 (with a group size of -N), while a positive\n\
 316                                 value allows two groups of input sections, one\n\
 317                                 before, and one after each stub section.\n\
 318                                 Values of +/-1 indicate the linker should\n\
 319                                 choose suitable defaults.\n"
 320                    ));
 321 '
 322
 323 PARSE_AND_LIST_ARGS_CASES='
 324     case OPTION_STUBGROUP_SIZE:
 325       {
 326         const char *end;
 327         group_size = bfd_scan_vma (optarg, &end, 0);
 328         if (*end)
 329           einfo (_("%P%F: invalid number `%s'\''\n"), optarg);
 330       }
 331       break;
 332 '
 333
 334 # Put these extra metagelf routines in ld_${EMULATION_NAME}_emulation
 335 #
 336 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 337 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=metagelf_create_output_section_statements