ld/emultempl/avrelf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2006-2015 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 transfered
  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   /* We only need stubs for avr6, avrxmega6, and avrxmega7. */
  75   if (strcmp ("${EMULATION_NAME}","avr6")
  76       && strcmp ("${EMULATION_NAME}","avrxmega6")
  77       && strcmp ("${EMULATION_NAME}","avrxmega7") )
  78     avr_no_stubs = TRUE;
  79
  80   avr_elf_set_global_bfd_parameters ();
  81
  82   /* If generating a relocatable output file, then
  83      we don't  have to generate the trampolines.  */
  84   if (bfd_link_relocatable (&link_info))
  85     avr_no_stubs = TRUE;
  86
  87   if (avr_no_stubs)
  88     return;
  89
  90   ret = elf32_avr_setup_section_lists (link_info.output_bfd, &link_info);
  91
  92   if (ret < 0)
  93     einfo ("%X%P: can not setup the input section list: %E\n");
  94
  95   if (ret <= 0)
  96     return;
  97
  98   /* Call into the BFD backend to do the real "stub"-work.  */
  99   if (! elf32_avr_size_stubs (link_info.output_bfd, &link_info, TRUE))
 100     einfo ("%X%P: can not size stub section: %E\n");
 101 }
 102
 103 /* This is called before the input files are opened.  We create a new
 104    fake input file to hold the stub section and generate the section itself.  */
 105
 106 static void
 107 avr_elf_create_output_section_statements (void)
 108 {
 109   flagword flags;
 110
 111   stub_file = lang_add_input_file ("linker stubs",
 112                                    lang_input_file_is_fake_enum,
 113                                    NULL);
 114
 115   stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
 116   if (stub_file->the_bfd == NULL
 117       || !bfd_set_arch_mach (stub_file->the_bfd,
 118                              bfd_get_arch (link_info.output_bfd),
 119                              bfd_get_mach (link_info.output_bfd)))
 120     {
 121       einfo ("%X%P: can not create stub BFD %E\n");
 122       return;
 123     }
 124
 125   /* Now we add the stub section.  */
 126
 127   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 128            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 129   avr_stub_section = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
 130                                                          ".trampolines",
 131                                                          flags);
 132   if (avr_stub_section == NULL)
 133     goto err_ret;
 134
 135   avr_stub_section->alignment_power = 1;
 136
 137   ldlang_add_file (stub_file);
 138
 139   return;
 140
 141   err_ret:
 142    einfo ("%X%P: can not make stub section: %E\n");
 143    return;
 144 }
 145
 146 /* Re-calculates the size of the stubs so that we won't waste space.  */
 147
 148 static void
 149 avr_elf_after_allocation (void)
 150 {
 151   if (!avr_no_stubs && ! RELAXATION_ENABLED)
 152     {
 153       /* If relaxing, elf32_avr_size_stubs will be called from
 154          elf32_avr_relax_section.  */
 155       if (!elf32_avr_size_stubs (link_info.output_bfd, &link_info, TRUE))
 156         einfo ("%X%P: can not size stub section: %E\n");
 157     }
 158
 159   gld${EMULATION_NAME}_after_allocation ();
 160
 161   /* Now build the linker stubs.  */
 162   if (!avr_no_stubs)
 163     {
 164       if (!elf32_avr_build_stubs (&link_info))
 165         einfo ("%X%P: can not build stubs: %E\n");
 166     }
 167 }
 168
 169 static void
 170 avr_elf_before_parse (void)
 171 {
 172   /* Don't create a demand-paged executable, since this feature isn't
 173      meaningful in AVR. */
 174   config.magic_demand_paged = FALSE;
 175
 176   gld${EMULATION_NAME}_before_parse ();
 177 }
 178
 179 static void
 180 avr_finish (void)
 181 {
 182   bfd *abfd;
 183   bfd_boolean avr_link_relax;
 184
 185   if (bfd_link_relocatable (&link_info))
 186     {
 187       avr_link_relax = TRUE;
 188       for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
 189         {
 190           /* Don't let the linker stubs prevent the final object being
 191              marked as link-relax ready.  */
 192           if ((elf_elfheader (abfd)->e_flags
 193                & EF_AVR_LINKRELAX_PREPARED) == 0
 194               && abfd != stub_file->the_bfd)
 195             {
 196               avr_link_relax = FALSE;
 197               break;
 198             }
 199         }
 200     }
 201   else
 202     {
 203       avr_link_relax = RELAXATION_ENABLED;
 204     }
 205
 206   abfd = link_info.output_bfd;
 207   if (avr_link_relax)
 208     elf_elfheader (abfd)->e_flags |= EF_AVR_LINKRELAX_PREPARED;
 209   else
 210     elf_elfheader (abfd)->e_flags &= ~EF_AVR_LINKRELAX_PREPARED;
 211
 212   finish_default ();
 213 }
 214 EOF
 215
 216
 217 PARSE_AND_LIST_PROLOGUE='
 218
 219 #define OPTION_NO_CALL_RET_REPLACEMENT 301
 220 #define OPTION_PMEM_WRAP_AROUND        302
 221 #define OPTION_NO_STUBS                303
 222 #define OPTION_DEBUG_STUBS             304
 223 #define OPTION_DEBUG_RELAX             305
 224 '
 225
 226 PARSE_AND_LIST_LONGOPTS='
 227   { "no-call-ret-replacement", no_argument,
 228      NULL, OPTION_NO_CALL_RET_REPLACEMENT},
 229   { "pmem-wrap-around", required_argument,
 230     NULL, OPTION_PMEM_WRAP_AROUND},
 231   { "no-stubs", no_argument,
 232     NULL, OPTION_NO_STUBS},
 233   { "debug-stubs", no_argument,
 234     NULL, OPTION_DEBUG_STUBS},
 235   { "debug-relax", no_argument,
 236     NULL, OPTION_DEBUG_RELAX},
 237 '
 238
 239 PARSE_AND_LIST_OPTIONS='
 240   fprintf (file, _("  --pmem-wrap-around=<val>    "
 241                    "Make the linker relaxation machine assume that a\n"
 242                    "                              "
 243                    "  program counter wrap-around occures at address\n"
 244                    "                              "
 245                    "  <val>.  Supported values: 8k, 16k, 32k and 64k.\n"));
 246   fprintf (file, _("  --no-call-ret-replacement   "
 247                    "The relaxation machine normally will\n"
 248                    "                              "
 249                    "  substitute two immediately following call/ret\n"
 250                    "                              "
 251                    "  instructions by a single jump instruction.\n"
 252                    "                              "
 253                    "  This option disables this optimization.\n"));
 254   fprintf (file, _("  --no-stubs                  "
 255                    "If the linker detects to attempt to access\n"
 256                    "                              "
 257                    "  an instruction beyond 128k by a reloc that\n"
 258                    "                              "
 259                    "  is limited to 128k max, it inserts a jump\n"
 260                    "                              "
 261                    "  stub. You can de-active this with this switch.\n"));
 262   fprintf (file, _("  --debug-stubs               "
 263                    "Used for debugging avr-ld.\n"));
 264   fprintf (file, _("  --debug-relax               "
 265                    "Used for debugging avr-ld.\n"));
 266 '
 267
 268 PARSE_AND_LIST_ARGS_CASES='
 269
 270     case OPTION_PMEM_WRAP_AROUND:
 271       {
 272         /* This variable is defined in the bfd library.  */
 273         if ((!strcmp (optarg,"32k"))      || (!strcmp (optarg,"32K")))
 274           avr_pc_wrap_around = 32768;
 275         else if ((!strcmp (optarg,"8k")) || (!strcmp (optarg,"8K")))
 276           avr_pc_wrap_around = 8192;
 277         else if ((!strcmp (optarg,"16k")) || (!strcmp (optarg,"16K")))
 278           avr_pc_wrap_around = 16384;
 279         else if ((!strcmp (optarg,"64k")) || (!strcmp (optarg,"64K")))
 280           avr_pc_wrap_around = 0x10000;
 281         else
 282           return FALSE;
 283       }
 284       break;
 285
 286     case OPTION_DEBUG_STUBS:
 287       avr_debug_stubs = TRUE;
 288       break;
 289
 290     case OPTION_DEBUG_RELAX:
 291       avr_debug_relax = TRUE;
 292       break;
 293
 294     case OPTION_NO_STUBS:
 295       avr_no_stubs = TRUE;
 296       break;
 297
 298     case OPTION_NO_CALL_RET_REPLACEMENT:
 299       {
 300         /* This variable is defined in the bfd library.  */
 301         avr_replace_call_ret_sequences = FALSE;
 302       }
 303       break;
 304 '
 305
 306 #
 307 # Put these extra avr-elf routines in ld_${EMULATION_NAME}_emulation
 308 #
 309 LDEMUL_BEFORE_PARSE=avr_elf_before_parse
 310 LDEMUL_BEFORE_ALLOCATION=avr_elf_${EMULATION_NAME}_before_allocation
 311 LDEMUL_AFTER_ALLOCATION=avr_elf_after_allocation
 312 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=avr_elf_create_output_section_statements
 313 LDEMUL_FINISH=avr_finish