ld/emultempl/avrelf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2006-2017 Free Software Foundation, Inc.
   3 #
   4 # This file is part of the 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 avr-elf specific
  23 # routines.  It is used to generate the trampolines for the avr6 family
  24 # of devices where one needs to address the issue that it is not possible
  25 # to reach the whole program memory by using 16 bit pointers.
  26
  27 fragment <<EOF
  28
  29 #include "elf32-avr.h"
  30 #include "ldctor.h"
  31 #include "elf/avr.h"
  32
  33 /* The fake file and it's corresponding section meant to hold
  34    the linker stubs if needed.  */
  35
  36 static lang_input_statement_type *stub_file;
  37 static asection *avr_stub_section;
  38
  39 /* Variables set by the command-line parameters and transferred
  40    to the bfd without use of global shared variables.  */
  41
  42 static bfd_boolean avr_no_stubs = FALSE;
  43 static bfd_boolean avr_debug_relax = FALSE;
  44 static bfd_boolean avr_debug_stubs = FALSE;
  45 static bfd_boolean avr_replace_call_ret_sequences = TRUE;
  46 static bfd_vma avr_pc_wrap_around = 0x10000000;
  47
  48 /* Transfers information to the bfd frontend.  */
  49
  50 static void
  51 avr_elf_set_global_bfd_parameters (void)
  52 {
  53   elf32_avr_setup_params (& link_info,
  54                           stub_file->the_bfd,
  55                           avr_stub_section,
  56                           avr_no_stubs,
  57                           avr_debug_stubs,
  58                           avr_debug_relax,
  59                           avr_pc_wrap_around,
  60                           avr_replace_call_ret_sequences);
  61 }
  62
  63
  64 /* Makes a conservative estimate of the trampoline section size that could
  65    be corrected later on.  */
  66
  67 static void
  68 avr_elf_${EMULATION_NAME}_before_allocation (void)
  69 {
  70   int ret;
  71
  72   gld${EMULATION_NAME}_before_allocation ();
  73
  74   if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
  75     {
  76       avr_no_stubs = TRUE;
  77       return;
  78     }
  79
  80   /* We only need stubs for avr6, avrxmega6, and avrxmega7. */
  81   if (strcmp ("${EMULATION_NAME}","avr6")
  82       && strcmp ("${EMULATION_NAME}","avrxmega6")
  83       && strcmp ("${EMULATION_NAME}","avrxmega7") )
  84     avr_no_stubs = TRUE;
  85
  86   avr_elf_set_global_bfd_parameters ();
  87
  88   /* If generating a relocatable output file, then
  89      we don't  have to generate the trampolines.  */
  90   if (bfd_link_relocatable (&link_info))
  91     avr_no_stubs = TRUE;
  92
  93   if (avr_no_stubs)
  94     return;
  95
  96   ret = elf32_avr_setup_section_lists (link_info.output_bfd, &link_info);
  97
  98   if (ret < 0)
  99     einfo ("%X%P: can not setup the input section list: %E\n");
 100
 101   if (ret <= 0)
 102     return;
 103
 104   /* Call into the BFD backend to do the real "stub"-work.  */
 105   if (! elf32_avr_size_stubs (link_info.output_bfd, &link_info, TRUE))
 106     einfo ("%X%P: can not size stub section: %E\n");
 107 }
 108
 109 /* This is called before the input files are opened.  We create a new
 110    fake input file to hold the stub section and generate the section itself.  */
 111
 112 static void
 113 avr_elf_create_output_section_statements (void)
 114 {
 115   flagword flags;
 116
 117   if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
 118     {
 119       einfo ("%X%P: changing output format whilst linking is not supported\n");
 120       return;
 121     }
 122
 123   stub_file = lang_add_input_file ("linker stubs",
 124                                    lang_input_file_is_fake_enum,
 125                                    NULL);
 126
 127   stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
 128   if (stub_file->the_bfd == NULL
 129       || !bfd_set_arch_mach (stub_file->the_bfd,
 130                              bfd_get_arch (link_info.output_bfd),
 131                              bfd_get_mach (link_info.output_bfd)))
 132     {
 133       einfo ("%X%P: can not create stub BFD %E\n");
 134       return;
 135     }
 136
 137   /* Now we add the stub section.  */
 138
 139   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 140            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 141   avr_stub_section = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
 142                                                          ".trampolines",
 143                                                          flags);
 144   if (avr_stub_section == NULL)
 145     goto err_ret;
 146
 147   avr_stub_section->alignment_power = 1;
 148
 149   ldlang_add_file (stub_file);
 150
 151   return;
 152
 153   err_ret:
 154    einfo ("%X%P: can not make stub section: %E\n");
 155    return;
 156 }
 157
 158 /* Re-calculates the size of the stubs so that we won't waste space.  */
 159
 160 static void
 161 avr_elf_after_allocation (void)
 162 {
 163   if (!avr_no_stubs && ! RELAXATION_ENABLED)
 164     {
 165       /* If relaxing, elf32_avr_size_stubs will be called from
 166          elf32_avr_relax_section.  */
 167       if (!elf32_avr_size_stubs (link_info.output_bfd, &link_info, TRUE))
 168         einfo ("%X%P: can not size stub section: %E\n");
 169     }
 170
 171   gld${EMULATION_NAME}_after_allocation ();
 172
 173   /* Now build the linker stubs.  */
 174   if (!avr_no_stubs)
 175     {
 176       if (!elf32_avr_build_stubs (&link_info))
 177         einfo ("%X%P: can not build stubs: %E\n");
 178     }
 179 }
 180
 181 static void
 182 avr_elf_before_parse (void)
 183 {
 184   /* Don't create a demand-paged executable, since this feature isn't
 185      meaningful in AVR. */
 186   config.magic_demand_paged = FALSE;
 187
 188   gld${EMULATION_NAME}_before_parse ();
 189 }
 190
 191 static void
 192 avr_finish (void)
 193 {
 194   bfd *abfd;
 195   bfd_boolean avr_link_relax;
 196
 197   if (bfd_link_relocatable (&link_info))
 198     {
 199       avr_link_relax = TRUE;
 200       for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
 201         {
 202           /* Don't let the linker stubs prevent the final object being
 203              marked as link-relax ready.  */
 204           if ((elf_elfheader (abfd)->e_flags
 205                & EF_AVR_LINKRELAX_PREPARED) == 0
 206               && abfd != stub_file->the_bfd)
 207             {
 208               avr_link_relax = FALSE;
 209               break;
 210             }
 211         }
 212     }
 213   else
 214     {
 215       avr_link_relax = RELAXATION_ENABLED;
 216     }
 217
 218   abfd = link_info.output_bfd;
 219
 220   if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
 221     {
 222       if (avr_link_relax)
 223         elf_elfheader (abfd)->e_flags |= EF_AVR_LINKRELAX_PREPARED;
 224       else
 225         elf_elfheader (abfd)->e_flags &= ~EF_AVR_LINKRELAX_PREPARED;
 226     }
 227
 228   finish_default ();
 229 }
 230 EOF
 231
 232
 233 PARSE_AND_LIST_PROLOGUE='
 234
 235 #define OPTION_NO_CALL_RET_REPLACEMENT 301
 236 #define OPTION_PMEM_WRAP_AROUND        302
 237 #define OPTION_NO_STUBS                303
 238 #define OPTION_DEBUG_STUBS             304
 239 #define OPTION_DEBUG_RELAX             305
 240 '
 241
 242 PARSE_AND_LIST_LONGOPTS='
 243   { "no-call-ret-replacement", no_argument,
 244      NULL, OPTION_NO_CALL_RET_REPLACEMENT},
 245   { "pmem-wrap-around", required_argument,
 246     NULL, OPTION_PMEM_WRAP_AROUND},
 247   { "no-stubs", no_argument,
 248     NULL, OPTION_NO_STUBS},
 249   { "debug-stubs", no_argument,
 250     NULL, OPTION_DEBUG_STUBS},
 251   { "debug-relax", no_argument,
 252     NULL, OPTION_DEBUG_RELAX},
 253 '
 254
 255 PARSE_AND_LIST_OPTIONS='
 256   fprintf (file, _("  --pmem-wrap-around=<val>    "
 257                    "Make the linker relaxation machine assume that a\n"
 258                    "                              "
 259                    "  program counter wrap-around occures at address\n"
 260                    "                              "
 261                    "  <val>.  Supported values: 8k, 16k, 32k and 64k.\n"));
 262   fprintf (file, _("  --no-call-ret-replacement   "
 263                    "The relaxation machine normally will\n"
 264                    "                              "
 265                    "  substitute two immediately following call/ret\n"
 266                    "                              "
 267                    "  instructions by a single jump instruction.\n"
 268                    "                              "
 269                    "  This option disables this optimization.\n"));
 270   fprintf (file, _("  --no-stubs                  "
 271                    "If the linker detects to attempt to access\n"
 272                    "                              "
 273                    "  an instruction beyond 128k by a reloc that\n"
 274                    "                              "
 275                    "  is limited to 128k max, it inserts a jump\n"
 276                    "                              "
 277                    "  stub. You can de-active this with this switch.\n"));
 278   fprintf (file, _("  --debug-stubs               "
 279                    "Used for debugging avr-ld.\n"));
 280   fprintf (file, _("  --debug-relax               "
 281                    "Used for debugging avr-ld.\n"));
 282 '
 283
 284 PARSE_AND_LIST_ARGS_CASES='
 285
 286     case OPTION_PMEM_WRAP_AROUND:
 287       {
 288         /* This variable is defined in the bfd library.  */
 289         if ((!strcmp (optarg,"32k"))      || (!strcmp (optarg,"32K")))
 290           avr_pc_wrap_around = 32768;
 291         else if ((!strcmp (optarg,"8k")) || (!strcmp (optarg,"8K")))
 292           avr_pc_wrap_around = 8192;
 293         else if ((!strcmp (optarg,"16k")) || (!strcmp (optarg,"16K")))
 294           avr_pc_wrap_around = 16384;
 295         else if ((!strcmp (optarg,"64k")) || (!strcmp (optarg,"64K")))
 296           avr_pc_wrap_around = 0x10000;
 297         else
 298           return FALSE;
 299       }
 300       break;
 301
 302     case OPTION_DEBUG_STUBS:
 303       avr_debug_stubs = TRUE;
 304       break;
 305
 306     case OPTION_DEBUG_RELAX:
 307       avr_debug_relax = TRUE;
 308       break;
 309
 310     case OPTION_NO_STUBS:
 311       avr_no_stubs = TRUE;
 312       break;
 313
 314     case OPTION_NO_CALL_RET_REPLACEMENT:
 315       {
 316         /* This variable is defined in the bfd library.  */
 317         avr_replace_call_ret_sequences = FALSE;
 318       }
 319       break;
 320 '
 321
 322 #
 323 # Put these extra avr-elf routines in ld_${EMULATION_NAME}_emulation
 324 #
 325 LDEMUL_BEFORE_PARSE=avr_elf_before_parse
 326 LDEMUL_BEFORE_ALLOCATION=avr_elf_${EMULATION_NAME}_before_allocation
 327 LDEMUL_AFTER_ALLOCATION=avr_elf_after_allocation
 328 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=avr_elf_create_output_section_statements
 329 LDEMUL_FINISH=avr_finish