ld/emultempl/m68kelf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2000-2015 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       && (! link_info.relocatable))
  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           /* As first-order business, make sure that each input BFD is either
  83              COFF or ELF.  We need to call a special BFD backend function to
  84              generate the embedded relocs, and we have such functions only for
  85              COFF and ELF.  */
  86           if (bfd_get_flavour (abfd) != bfd_target_coff_flavour
  87               && bfd_get_flavour (abfd) != bfd_target_elf_flavour)
  88             einfo ("%F%B: all input objects must be COFF or ELF for --embedded-relocs\n");
  89
  90           datasec = bfd_get_section_by_name (abfd, ".data");
  91
  92           /* Note that we assume that the reloc_count field has already
  93              been set up.  We could call bfd_get_reloc_upper_bound, but
  94              that returns the size of a memory buffer rather than a reloc
  95              count.  We do not want to call bfd_canonicalize_reloc,
  96              because although it would always work it would force us to
  97              read in the relocs into BFD canonical form, which would waste
  98              a significant amount of time and memory.  */
  99           if (datasec != NULL && datasec->reloc_count > 0)
 100             {
 101               asection *relsec;
 102
 103               relsec = bfd_make_section_with_flags (abfd, ".emreloc",
 104                                                     (SEC_ALLOC
 105                                                     | SEC_LOAD
 106                                                     | SEC_HAS_CONTENTS
 107                                                     | SEC_IN_MEMORY));
 108               if (relsec == NULL
 109                   || ! bfd_set_section_alignment (abfd, relsec, 2)
 110                   || ! bfd_set_section_size (abfd, relsec,
 111                                              datasec->reloc_count * 12))
 112                 einfo ("%F%B: can not create .emreloc section: %E\n");
 113             }
 114
 115           /* Double check that all other data sections are empty, as is
 116              required for embedded PIC code.  */
 117           bfd_map_over_sections (abfd, check_sections, datasec);
 118         }
 119     }
 120 #endif /* SUPPORT_EMBEDDED_RELOCS */
 121 }
 122
 123 #ifdef SUPPORT_EMBEDDED_RELOCS
 124 /* Check that of the data sections, only the .data section has
 125    relocs.  This is called via bfd_map_over_sections.  */
 126
 127 static void
 128 check_sections (bfd *abfd, asection *sec, void *datasec)
 129 {
 130   if ((bfd_get_section_flags (abfd, sec) & SEC_DATA)
 131       && sec != datasec
 132       && sec->reloc_count != 0)
 133     einfo ("%B%X: section %s has relocs; can not use --embedded-relocs\n",
 134            abfd, bfd_get_section_name (abfd, sec));
 135 }
 136
 137 #endif /* SUPPORT_EMBEDDED_RELOCS */
 138
 139 /* This function is called after the section sizes and offsets have
 140    been set.  */
 141
 142 static void
 143 m68k_elf_after_allocation (void)
 144 {
 145   /* Call the standard elf routine.  */
 146   gld${EMULATION_NAME}_after_allocation ();
 147
 148 #ifdef SUPPORT_EMBEDDED_RELOCS
 149   if (command_line.embedded_relocs
 150       && (! link_info.relocatable))
 151     {
 152       bfd *abfd;
 153
 154       /* If we are generating embedded relocs, call a special BFD backend
 155          routine to do the work.  */
 156       for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
 157         {
 158           asection *datasec, *relsec;
 159           char *errmsg;
 160
 161           datasec = bfd_get_section_by_name (abfd, ".data");
 162
 163           if (datasec == NULL || datasec->reloc_count == 0)
 164             continue;
 165
 166           relsec = bfd_get_section_by_name (abfd, ".emreloc");
 167           ASSERT (relsec != NULL);
 168
 169           if (bfd_get_flavour (abfd) == bfd_target_coff_flavour)
 170             {
 171               if (! bfd_m68k_coff_create_embedded_relocs (abfd, &link_info,
 172                                                           datasec, relsec,
 173                                                           &errmsg))
 174                 {
 175                   if (errmsg == NULL)
 176                     einfo ("%B%X: can not create runtime reloc information: %E\n",
 177                            abfd);
 178                   else
 179                     einfo ("%X%B: can not create runtime reloc information: %s\n",
 180                            abfd, errmsg);
 181                 }
 182             }
 183           else if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 184             {
 185               if (! bfd_m68k_elf32_create_embedded_relocs (abfd, &link_info,
 186                                                            datasec, relsec,
 187                                                            &errmsg))
 188                 {
 189                   if (errmsg == NULL)
 190                     einfo ("%B%X: can not create runtime reloc information: %E\n",
 191                            abfd);
 192                   else
 193                     einfo ("%X%B: can not create runtime reloc information: %s\n",
 194                            abfd, errmsg);
 195                 }
 196             }
 197           else
 198             abort ();
 199         }
 200     }
 201 #endif /* SUPPORT_EMBEDDED_RELOCS */
 202 }
 203
 204 /* This is a convenient point to tell BFD about target specific flags.
 205    After the output has been created, but before inputs are read.  */
 206
 207 static void
 208 elf_m68k_create_output_section_statements (void)
 209 {
 210   bfd_elf_m68k_set_target_options (&link_info, got_handling);
 211 }
 212
 213 EOF
 214
 215 # Define some shell vars to insert bits of code into the standard elf
 216 # parse_args and list_options functions.
 217 #
 218 PARSE_AND_LIST_PROLOGUE='
 219 #define OPTION_GOT      301
 220 '
 221
 222 PARSE_AND_LIST_LONGOPTS='
 223   { "got", required_argument, NULL, OPTION_GOT},
 224 '
 225
 226 PARSE_AND_LIST_OPTIONS='
 227   fprintf (file, _("  --got=<type>                Specify GOT handling scheme\n"));
 228 '
 229
 230 PARSE_AND_LIST_ARGS_CASES='
 231     case OPTION_GOT:
 232       if (strcmp (optarg, "target") == 0)
 233         got_handling = GOT_HANDLING_TARGET_DEFAULT;
 234       else if (strcmp (optarg, "single") == 0)
 235         got_handling = 0;
 236       else if (strcmp (optarg, "negative") == 0)
 237         got_handling = 1;
 238       else if (strcmp (optarg, "multigot") == 0)
 239         got_handling = 2;
 240       else
 241         einfo (_("Unrecognized --got argument '\''%s'\''.\n"), optarg);
 242       break;
 243 '
 244
 245 # We have our own after_open and after_allocation functions, but they call
 246 # the standard routines, so give them a different name.
 247 LDEMUL_AFTER_OPEN=m68k_elf_after_open
 248 LDEMUL_AFTER_ALLOCATION=m68k_elf_after_allocation
 249 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=elf_m68k_create_output_section_statements