ld/emultempl/m68kelf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2000-2019 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 elf.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 elf.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 (relsec, 2)
 106                   || !bfd_set_section_size (relsec, datasec->reloc_count * 12))
 107                 einfo (_("%F%P: %pB: can not create .emreloc section: %E\n"));
 108             }
 109
 110           /* Double check that all other data sections are empty, as is
 111              required for embedded PIC code.  */
 112           bfd_map_over_sections (abfd, check_sections, datasec);
 113         }
 114     }
 115 #endif /* SUPPORT_EMBEDDED_RELOCS */
 116 }
 117
 118 #ifdef SUPPORT_EMBEDDED_RELOCS
 119 /* Check that of the data sections, only the .data section has
 120    relocs.  This is called via bfd_map_over_sections.  */
 121
 122 static void
 123 check_sections (bfd *abfd, asection *sec, void *datasec)
 124 {
 125   if ((bfd_section_flags (sec) & SEC_DATA)
 126       && sec != datasec
 127       && sec->reloc_count != 0)
 128     einfo (_("%X%P: %pB: section %s has relocs; can not use --embedded-relocs\n"),
 129            abfd, bfd_section_name (sec));
 130 }
 131
 132 #endif /* SUPPORT_EMBEDDED_RELOCS */
 133
 134 /* This function is called after the section sizes and offsets have
 135    been set.  */
 136
 137 static void
 138 m68k_elf_after_allocation (void)
 139 {
 140   /* Call the standard elf routine.  */
 141   gld${EMULATION_NAME}_after_allocation ();
 142
 143 #ifdef SUPPORT_EMBEDDED_RELOCS
 144   if (command_line.embedded_relocs
 145       && (!bfd_link_relocatable (&link_info)))
 146     {
 147       bfd *abfd;
 148
 149       /* If we are generating embedded relocs, call a special BFD backend
 150          routine to do the work.  */
 151       for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
 152         {
 153           asection *datasec, *relsec;
 154           char *errmsg;
 155
 156           datasec = bfd_get_section_by_name (abfd, ".data");
 157
 158           if (datasec == NULL || datasec->reloc_count == 0)
 159             continue;
 160
 161           relsec = bfd_get_section_by_name (abfd, ".emreloc");
 162           ASSERT (relsec != NULL);
 163
 164           if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 165             {
 166               if (! bfd_m68k_elf32_create_embedded_relocs (abfd, &link_info,
 167                                                            datasec, relsec,
 168                                                            &errmsg))
 169                 {
 170                   if (errmsg == NULL)
 171                     einfo (_("%X%P: %pB: can not create "
 172                              "runtime reloc information: %E\n"),
 173                            abfd);
 174                   else
 175                     einfo (_("%X%P: %pB: can not create "
 176                              "runtime reloc information: %s\n"),
 177                            abfd, errmsg);
 178                 }
 179             }
 180           else
 181             abort ();
 182         }
 183     }
 184 #endif /* SUPPORT_EMBEDDED_RELOCS */
 185 }
 186
 187 /* This is a convenient point to tell BFD about target specific flags.
 188    After the output has been created, but before inputs are read.  */
 189
 190 static void
 191 elf_m68k_create_output_section_statements (void)
 192 {
 193   bfd_elf_m68k_set_target_options (&link_info, got_handling);
 194 }
 195
 196 EOF
 197
 198 # Define some shell vars to insert bits of code into the standard elf
 199 # parse_args and list_options functions.
 200 #
 201 PARSE_AND_LIST_PROLOGUE='
 202 #define OPTION_GOT      301
 203 '
 204
 205 PARSE_AND_LIST_LONGOPTS='
 206   { "got", required_argument, NULL, OPTION_GOT},
 207 '
 208
 209 PARSE_AND_LIST_OPTIONS='
 210   fprintf (file, _("  --got=<type>                Specify GOT handling scheme\n"));
 211 '
 212
 213 PARSE_AND_LIST_ARGS_CASES='
 214     case OPTION_GOT:
 215       if (strcmp (optarg, "target") == 0)
 216         got_handling = GOT_HANDLING_TARGET_DEFAULT;
 217       else if (strcmp (optarg, "single") == 0)
 218         got_handling = 0;
 219       else if (strcmp (optarg, "negative") == 0)
 220         got_handling = 1;
 221       else if (strcmp (optarg, "multigot") == 0)
 222         got_handling = 2;
 223       else
 224         einfo (_("%P: unrecognized --got argument '\''%s'\''\n"), optarg);
 225       break;
 226 '
 227
 228 # We have our own after_open and after_allocation functions, but they call
 229 # the standard routines, so give them a different name.
 230 LDEMUL_AFTER_OPEN=m68k_elf_after_open
 231 LDEMUL_AFTER_ALLOCATION=m68k_elf_after_allocation
 232 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=elf_m68k_create_output_section_statements