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   lang_output_section_statement_type *os;
 158   struct hook_stub_info info;
 159
 160   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 161            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 162   stub_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
 163                                                  stub_sec_name, flags);
 164   if (stub_sec == NULL)
 165     goto err_ret;
 166
 167   output_section = input_section->output_section;
 168   os = lang_output_section_get (output_section);
 169
 170   info.input_section = input_section;
 171   lang_list_init (&info.add);
 172   lang_add_section (&info.add, stub_sec, NULL, os);
 173
 174   if (info.add.head == NULL)
 175     goto err_ret;
 176
 177   if (hook_in_stub (&info, &os->children.head))
 178     return stub_sec;
 179
 180  err_ret:
 181   einfo ("%X%P: can not make stub section: %E\n");
 182   return NULL;
 183 }
 184
 185
 186 /* Another call-back for elf_metag_size_stubs.  */
 187
 188 static void
 189 metagelf_layout_sections_again (void)
 190 {
 191   /* If we have changed sizes of the stub sections, then we need
 192      to recalculate all the section offsets.  This may mean we need to
 193      add even more stubs.  */
 194   gld${EMULATION_NAME}_map_segments (TRUE);
 195   need_laying_out = -1;
 196 }
 197
 198
 199 static void
 200 build_section_lists (lang_statement_union_type *statement)
 201 {
 202   if (statement->header.type == lang_input_section_enum)
 203     {
 204       asection *i = statement->input_section.section;
 205
 206       if (i->sec_info_type != SEC_INFO_TYPE_JUST_SYMS
 207           && (i->flags & SEC_EXCLUDE) == 0
 208           && i->output_section != NULL
 209           && i->output_section->owner == link_info.output_bfd)
 210         {
 211           elf_metag_next_input_section (&link_info, i);
 212         }
 213     }
 214 }
 215
 216
 217 /* For Meta we use this opportunity to build linker stubs.  */
 218
 219 static void
 220 gld${EMULATION_NAME}_after_allocation (void)
 221 {
 222   /* bfd_elf_discard_info just plays with data and debugging sections,
 223      ie. doesn't affect code size, so we can delay resizing the
 224      sections.  It's likely we'll resize everything in the process of
 225      adding stubs.  */
 226   if (bfd_elf_discard_info (link_info.output_bfd, &link_info))
 227     need_laying_out = 1;
 228
 229   /* If generating a relocatable output file, then we don't
 230      have to examine the relocs.  */
 231   if (stub_file != NULL && !link_info.relocatable)
 232     {
 233       int ret = elf_metag_setup_section_lists (link_info.output_bfd,
 234                                                &link_info);
 235
 236       if (ret != 0)
 237         {
 238           if (ret < 0)
 239             {
 240               einfo ("%X%P: can not size stub section: %E\n");
 241               return;
 242             }
 243
 244           lang_for_each_statement (build_section_lists);
 245
 246           /* Call into the BFD backend to do the real work.  */
 247           if (! elf_metag_size_stubs (link_info.output_bfd,
 248                                       stub_file->the_bfd,
 249                                       &link_info,
 250                                       group_size,
 251                                       &metagelf_add_stub_section,
 252                                       &metagelf_layout_sections_again))
 253             {
 254               einfo ("%X%P: can not size stub section: %E\n");
 255               return;
 256             }
 257         }
 258     }
 259
 260   if (need_laying_out != -1)
 261     gld${EMULATION_NAME}_map_segments (need_laying_out);
 262
 263   if (! link_info.relocatable)
 264     {
 265       /* Now build the linker stubs.  */
 266       if (stub_file != NULL && stub_file->the_bfd->sections != NULL)
 267         {
 268           if (! elf_metag_build_stubs (&link_info))
 269             einfo ("%X%P: can not build stubs: %E\n");
 270         }
 271     }
 272 }
 273
 274
 275 /* Avoid processing the fake stub_file in vercheck, stat_needed and
 276    check_needed routines.  */
 277
 278 static void (*real_func) (lang_input_statement_type *);
 279
 280 static void metag_for_each_input_file_wrapper (lang_input_statement_type *l)
 281 {
 282   if (l != stub_file)
 283     (*real_func) (l);
 284 }
 285
 286 static void
 287 metag_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
 288 {
 289   real_func = func;
 290   lang_for_each_input_file (&metag_for_each_input_file_wrapper);
 291 }
 292
 293 #define lang_for_each_input_file metag_lang_for_each_input_file
 294
 295 EOF
 296
 297 # Define some shell vars to insert bits of code into the standard elf
 298 # parse_args and list_options functions.
 299 #
 300 PARSE_AND_LIST_PROLOGUE='
 301 #define OPTION_STUBGROUP_SIZE           301
 302 '
 303
 304 PARSE_AND_LIST_LONGOPTS='
 305   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 306 '
 307
 308 PARSE_AND_LIST_OPTIONS='
 309   fprintf (file, _("\
 310   --stub-group-size=N         Maximum size of a group of input sections that\n\
 311                                 can be handled by one stub section.  A negative\n\
 312                                 value locates all stubs before their branches\n\
 313                                 (with a group size of -N), while a positive\n\
 314                                 value allows two groups of input sections, one\n\
 315                                 before, and one after each stub section.\n\
 316                                 Values of +/-1 indicate the linker should\n\
 317                                 choose suitable defaults.\n"
 318                    ));
 319 '
 320
 321 PARSE_AND_LIST_ARGS_CASES='
 322     case OPTION_STUBGROUP_SIZE:
 323       {
 324         const char *end;
 325         group_size = bfd_scan_vma (optarg, &end, 0);
 326         if (*end)
 327           einfo (_("%P%F: invalid number `%s'\''\n"), optarg);
 328       }
 329       break;
 330 '
 331
 332 # Put these extra metagelf routines in ld_${EMULATION_NAME}_emulation
 333 #
 334 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 335 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=metagelf_create_output_section_statements