ld/emultempl/m68kelf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2000-2018 Free Software Foundation, Inc.
   3 #   Written by Michael Sokolov <msokolov@ivan.Harhan.ORG>, based on armelf.em
   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; if not, write to the Free Software
  19 # Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  20 # MA 02110-1301, USA.
  21
  22
  23 # This file is sourced from elf32.em, and defines some extra routines for m68k
  24 # embedded systems using ELF and for some other systems using m68k ELF.  While
  25 # it is sourced from elf32.em for all m68k ELF configurations, here we include
  26 # only the features we want depending on the configuration.
  27
  28 case ${target} in
  29   m68*-*-elf)
  30     echo "#define SUPPORT_EMBEDDED_RELOCS" >>e${EMULATION_NAME}.c
  31     ;;
  32 esac
  33
  34 case ${target} in
  35   *-linux*)
  36 # Don't use multi-GOT by default due to glibc linker's assumption
  37 # that GOT pointer points to GOT[0].
  38 #   got_handling_target_default=GOT_HANDLING_MULTIGOT
  39     got_handling_target_default=GOT_HANDLING_SINGLE
  40     ;;
  41   *)
  42     got_handling_target_default=GOT_HANDLING_SINGLE
  43     ;;
  44 esac
  45
  46 fragment <<EOF
  47
  48 #define GOT_HANDLING_SINGLE   (0)
  49 #define GOT_HANDLING_NEGATIVE (1)
  50 #define GOT_HANDLING_MULTIGOT (2)
  51 #define GOT_HANDLING_TARGET_DEFAULT ${got_handling_target_default}
  52
  53 /* How to generate GOT.  */
  54 static int got_handling = GOT_HANDLING_DEFAULT;
  55
  56 #ifdef SUPPORT_EMBEDDED_RELOCS
  57 static void check_sections (bfd *, asection *, void *);
  58 #endif
  59
  60 /* This function is run after all the input files have been opened.  */
  61
  62 static void
  63 m68k_elf_after_open (void)
  64 {
  65   /* Call the standard elf routine.  */
  66   gld${EMULATION_NAME}_after_open ();
  67
  68 #ifdef SUPPORT_EMBEDDED_RELOCS
  69   if (command_line.embedded_relocs
  70       && (!bfd_link_relocatable (&link_info)))
  71     {
  72       bfd *abfd;
  73
  74       /* In the embedded relocs mode we create a .emreloc section for each
  75          input file with a nonzero .data section.  The BFD backend will fill in
  76          these sections with magic numbers which can be used to relocate the
  77          data section at run time.  */
  78       for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
  79         {
  80           asection *datasec;
  81
  82           if (bfd_get_flavour (abfd) != bfd_target_elf_flavour)
  83             einfo (_("%F%P: %pB: all input objects must be ELF "
  84                      "for --embedded-relocs\n"));
  85
  86           datasec = bfd_get_section_by_name (abfd, ".data");
  87
  88           /* Note that we assume that the reloc_count field has already
  89              been set up.  We could call bfd_get_reloc_upper_bound, but
  90              that returns the size of a memory buffer rather than a reloc
  91              count.  We do not want to call bfd_canonicalize_reloc,
  92              because although it would always work it would force us to
  93              read in the relocs into BFD canonical form, which would waste
  94              a significant amount of time and memory.  */
  95           if (datasec != NULL && datasec->reloc_count > 0)
  96             {
  97               asection *relsec;
  98
  99               relsec = bfd_make_section_with_flags (abfd, ".emreloc",
 100                                                     (SEC_ALLOC
 101                                                     | SEC_LOAD
 102                                                     | SEC_HAS_CONTENTS
 103                                                     | SEC_IN_MEMORY));
 104               if (relsec == NULL
 105                   || ! bfd_set_section_alignment (abfd, relsec, 2)
 106                   || ! bfd_set_section_size (abfd, relsec,
 107                                              datasec->reloc_count * 12))
 108                 einfo (_("%F%P: %pB: can not create .emreloc section: %E\n"));
 109             }
 110
 111           /* Double check that all other data sections are empty, as is
 112              required for embedded PIC code.  */
 113           bfd_map_over_sections (abfd, check_sections, datasec);
 114         }
 115     }
 116 #endif /* SUPPORT_EMBEDDED_RELOCS */
 117 }
 118
 119 #ifdef SUPPORT_EMBEDDED_RELOCS
 120 /* Check that of the data sections, only the .data section has
 121    relocs.  This is called via bfd_map_over_sections.  */
 122
 123 static void
 124 check_sections (bfd *abfd, asection *sec, void *datasec)
 125 {
 126   if ((bfd_get_section_flags (abfd, sec) & SEC_DATA)
 127       && sec != datasec
 128       && sec->reloc_count != 0)
 129     einfo (_("%X%P: %pB: section %s has relocs; can not use --embedded-relocs\n"),
 130            abfd, bfd_get_section_name (abfd, sec));
 131 }
 132
 133 #endif /* SUPPORT_EMBEDDED_RELOCS */
 134
 135 /* This function is called after the section sizes and offsets have
 136    been set.  */
 137
 138 static void
 139 m68k_elf_after_allocation (void)
 140 {
 141   /* Call the standard elf routine.  */
 142   gld${EMULATION_NAME}_after_allocation ();
 143
 144 #ifdef SUPPORT_EMBEDDED_RELOCS
 145   if (command_line.embedded_relocs
 146       && (!bfd_link_relocatable (&link_info)))
 147     {
 148       bfd *abfd;
 149
 150       /* If we are generating embedded relocs, call a special BFD backend
 151          routine to do the work.  */
 152       for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
 153         {
 154           asection *datasec, *relsec;
 155           char *errmsg;
 156
 157           datasec = bfd_get_section_by_name (abfd, ".data");
 158
 159           if (datasec == NULL || datasec->reloc_count == 0)
 160             continue;
 161
 162           relsec = bfd_get_section_by_name (abfd, ".emreloc");
 163           ASSERT (relsec != NULL);
 164
 165           if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 166             {
 167               if (! bfd_m68k_elf32_create_embedded_relocs (abfd, &link_info,
 168                                                            datasec, relsec,
 169                                                            &errmsg))
 170                 {
 171                   if (errmsg == NULL)
 172                     einfo (_("%X%P: %pB: can not create "
 173                              "runtime reloc information: %E\n"),
 174                            abfd);
 175                   else
 176                     einfo (_("%X%P: %pB: can not create "
 177                              "runtime reloc information: %s\n"),
 178                            abfd, errmsg);
 179                 }
 180             }
 181           else
 182             abort ();
 183         }
 184     }
 185 #endif /* SUPPORT_EMBEDDED_RELOCS */
 186 }
 187
 188 /* This is a convenient point to tell BFD about target specific flags.
 189    After the output has been created, but before inputs are read.  */
 190
 191 static void
 192 elf_m68k_create_output_section_statements (void)
 193 {
 194   bfd_elf_m68k_set_target_options (&link_info, got_handling);
 195 }
 196
 197 EOF
 198
 199 # Define some shell vars to insert bits of code into the standard elf
 200 # parse_args and list_options functions.
 201 #
 202 PARSE_AND_LIST_PROLOGUE='
 203 #define OPTION_GOT      301
 204 '
 205
 206 PARSE_AND_LIST_LONGOPTS='
 207   { "got", required_argument, NULL, OPTION_GOT},
 208 '
 209
 210 PARSE_AND_LIST_OPTIONS='
 211   fprintf (file, _("  --got=<type>                Specify GOT handling scheme\n"));
 212 '
 213
 214 PARSE_AND_LIST_ARGS_CASES='
 215     case OPTION_GOT:
 216       if (strcmp (optarg, "target") == 0)
 217         got_handling = GOT_HANDLING_TARGET_DEFAULT;
 218       else if (strcmp (optarg, "single") == 0)
 219         got_handling = 0;
 220       else if (strcmp (optarg, "negative") == 0)
 221         got_handling = 1;
 222       else if (strcmp (optarg, "multigot") == 0)
 223         got_handling = 2;
 224       else
 225         einfo (_("%P: unrecognized --got argument '\''%s'\''\n"), optarg);
 226       break;
 227 '
 228
 229 # We have our own after_open and after_allocation functions, but they call
 230 # the standard routines, so give them a different name.
 231 LDEMUL_AFTER_OPEN=m68k_elf_after_open
 232 LDEMUL_AFTER_ALLOCATION=m68k_elf_after_allocation
 233 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=elf_m68k_create_output_section_statements