ld/emultempl/m68kelf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2000-2021 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 #include "elf32-m68k.h"
  49
  50 #define GOT_HANDLING_SINGLE   (0)
  51 #define GOT_HANDLING_NEGATIVE (1)
  52 #define GOT_HANDLING_MULTIGOT (2)
  53 #define GOT_HANDLING_TARGET_DEFAULT ${got_handling_target_default}
  54
  55 /* How to generate GOT.  */
  56 static int got_handling = GOT_HANDLING_DEFAULT;
  57
  58 #ifdef SUPPORT_EMBEDDED_RELOCS
  59 static void check_sections (bfd *, asection *, void *);
  60 #endif
  61
  62 /* This function is run after all the input files have been opened.  */
  63
  64 static void
  65 m68k_elf_after_open (void)
  66 {
  67   /* Call the standard elf routine.  */
  68   gld${EMULATION_NAME}_after_open ();
  69
  70 #ifdef SUPPORT_EMBEDDED_RELOCS
  71   if (command_line.embedded_relocs
  72       && (!bfd_link_relocatable (&link_info)))
  73     {
  74       bfd *abfd;
  75
  76       /* In the embedded relocs mode we create a .emreloc section for each
  77          input file with a nonzero .data section.  The BFD backend will fill in
  78          these sections with magic numbers which can be used to relocate the
  79          data section at run time.  */
  80       for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
  81         {
  82           asection *datasec;
  83
  84           if (bfd_get_flavour (abfd) != bfd_target_elf_flavour)
  85             einfo (_("%F%P: %pB: all input objects must be ELF "
  86                      "for --embedded-relocs\n"));
  87
  88           datasec = bfd_get_section_by_name (abfd, ".data");
  89
  90           /* Note that we assume that the reloc_count field has already
  91              been set up.  We could call bfd_get_reloc_upper_bound, but
  92              that returns the size of a memory buffer rather than a reloc
  93              count.  We do not want to call bfd_canonicalize_reloc,
  94              because although it would always work it would force us to
  95              read in the relocs into BFD canonical form, which would waste
  96              a significant amount of time and memory.  */
  97           if (datasec != NULL && datasec->reloc_count > 0)
  98             {
  99               asection *relsec;
 100
 101               relsec = bfd_make_section_with_flags (abfd, ".emreloc",
 102                                                     (SEC_ALLOC
 103                                                     | SEC_LOAD
 104                                                     | SEC_HAS_CONTENTS
 105                                                     | SEC_IN_MEMORY));
 106               if (relsec == NULL
 107                   || !bfd_set_section_alignment (relsec, 2)
 108                   || !bfd_set_section_size (relsec, datasec->reloc_count * 12))
 109                 einfo (_("%F%P: %pB: can not create .emreloc section: %E\n"));
 110             }
 111
 112           /* Double check that all other data sections are empty, as is
 113              required for embedded PIC code.  */
 114           bfd_map_over_sections (abfd, check_sections, datasec);
 115         }
 116     }
 117 #endif /* SUPPORT_EMBEDDED_RELOCS */
 118 }
 119
 120 #ifdef SUPPORT_EMBEDDED_RELOCS
 121 /* Check that of the data sections, only the .data section has
 122    relocs.  This is called via bfd_map_over_sections.  */
 123
 124 static void
 125 check_sections (bfd *abfd, asection *sec, void *datasec)
 126 {
 127   if ((bfd_section_flags (sec) & SEC_DATA)
 128       && sec != datasec
 129       && sec->reloc_count != 0)
 130     einfo (_("%X%P: %pB: section %s has relocs; can not use --embedded-relocs\n"),
 131            abfd, bfd_section_name (sec));
 132 }
 133
 134 #endif /* SUPPORT_EMBEDDED_RELOCS */
 135
 136 /* This function is called after the section sizes and offsets have
 137    been set.  */
 138
 139 static void
 140 m68k_elf_after_allocation (void)
 141 {
 142   /* Call the standard elf routine.  */
 143   gld${EMULATION_NAME}_after_allocation ();
 144
 145 #ifdef SUPPORT_EMBEDDED_RELOCS
 146   if (command_line.embedded_relocs
 147       && (!bfd_link_relocatable (&link_info)))
 148     {
 149       bfd *abfd;
 150
 151       /* If we are generating embedded relocs, call a special BFD backend
 152          routine to do the work.  */
 153       for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
 154         {
 155           asection *datasec, *relsec;
 156           char *errmsg;
 157
 158           datasec = bfd_get_section_by_name (abfd, ".data");
 159
 160           if (datasec == NULL || datasec->reloc_count == 0)
 161             continue;
 162
 163           relsec = bfd_get_section_by_name (abfd, ".emreloc");
 164           ASSERT (relsec != NULL);
 165
 166           if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 167             {
 168               if (! bfd_m68k_elf32_create_embedded_relocs (abfd, &link_info,
 169                                                            datasec, relsec,
 170                                                            &errmsg))
 171                 {
 172                   if (errmsg == NULL)
 173                     einfo (_("%X%P: %pB: can not create "
 174                              "runtime reloc information: %E\n"),
 175                            abfd);
 176                   else
 177                     einfo (_("%X%P: %pB: can not create "
 178                              "runtime reloc information: %s\n"),
 179                            abfd, errmsg);
 180                 }
 181             }
 182           else
 183             abort ();
 184         }
 185     }
 186 #endif /* SUPPORT_EMBEDDED_RELOCS */
 187 }
 188
 189 /* This is a convenient point to tell BFD about target specific flags.
 190    After the output has been created, but before inputs are read.  */
 191
 192 static void
 193 elf_m68k_create_output_section_statements (void)
 194 {
 195   bfd_elf_m68k_set_target_options (&link_info, got_handling);
 196 }
 197
 198 EOF
 199
 200 # Define some shell vars to insert bits of code into the standard elf
 201 # parse_args and list_options functions.
 202 #
 203 PARSE_AND_LIST_PROLOGUE='
 204 #define OPTION_GOT      301
 205 '
 206
 207 PARSE_AND_LIST_LONGOPTS='
 208   { "got", required_argument, NULL, OPTION_GOT},
 209 '
 210
 211 PARSE_AND_LIST_OPTIONS='
 212   fprintf (file, _("  --got=<type>                Specify GOT handling scheme\n"));
 213 '
 214
 215 PARSE_AND_LIST_ARGS_CASES='
 216     case OPTION_GOT:
 217       if (strcmp (optarg, "target") == 0)
 218         got_handling = GOT_HANDLING_TARGET_DEFAULT;
 219       else if (strcmp (optarg, "single") == 0)
 220         got_handling = 0;
 221       else if (strcmp (optarg, "negative") == 0)
 222         got_handling = 1;
 223       else if (strcmp (optarg, "multigot") == 0)
 224         got_handling = 2;
 225       else
 226         einfo (_("%P: unrecognized --got argument '\''%s'\''\n"), optarg);
 227       break;
 228 '
 229
 230 # We have our own after_open and after_allocation functions, but they call
 231 # the standard routines, so give them a different name.
 232 LDEMUL_AFTER_OPEN=m68k_elf_after_open
 233 LDEMUL_AFTER_ALLOCATION=m68k_elf_after_allocation
 234 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=elf_m68k_create_output_section_statements