ld/emultempl/avrelf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright 2006, 2007, 2008, 2009
   3 #   Free Software Foundation, Inc.
   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 extra avr-elf specific
  24 # routines.  It is used to generate the trampolines for the avr6 family
  25 # of devices where one needs to address the issue that it is not possible
  26 # to reach the whole program memory by using 16 bit pointers.
  27
  28 fragment <<EOF
  29
  30 #include "elf32-avr.h"
  31 #include "ldctor.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 (link_info.relocatable)
  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 EOF
 180
 181
 182 PARSE_AND_LIST_PROLOGUE='
 183
 184 #define OPTION_NO_CALL_RET_REPLACEMENT 301
 185 #define OPTION_PMEM_WRAP_AROUND        302
 186 #define OPTION_NO_STUBS                303
 187 #define OPTION_DEBUG_STUBS             304
 188 #define OPTION_DEBUG_RELAX             305
 189 '
 190
 191 PARSE_AND_LIST_LONGOPTS='
 192   { "no-call-ret-replacement", no_argument,
 193      NULL, OPTION_NO_CALL_RET_REPLACEMENT},
 194   { "pmem-wrap-around", required_argument,
 195     NULL, OPTION_PMEM_WRAP_AROUND},
 196   { "no-stubs", no_argument,
 197     NULL, OPTION_NO_STUBS},
 198   { "debug-stubs", no_argument,
 199     NULL, OPTION_DEBUG_STUBS},
 200   { "debug-relax", no_argument,
 201     NULL, OPTION_DEBUG_RELAX},
 202 '
 203
 204 PARSE_AND_LIST_OPTIONS='
 205   fprintf (file, _("  --pmem-wrap-around=<val>    "
 206                    "Make the linker relaxation machine assume that a\n"
 207                    "                              "
 208                    "  program counter wrap-around occures at address\n"
 209                    "                              "
 210                    "  <val>.  Supported values: 8k, 16k, 32k and 64k.\n"));
 211   fprintf (file, _("  --no-call-ret-replacement   "
 212                    "The relaxation machine normally will\n"
 213                    "                              "
 214                    "  substitute two immediately following call/ret\n"
 215                    "                              "
 216                    "  instructions by a single jump instruction.\n"
 217                    "                              "
 218                    "  This option disables this optimization.\n"));
 219   fprintf (file, _("  --no-stubs                  "
 220                    "If the linker detects to attempt to access\n"
 221                    "                              "
 222                    "  an instruction beyond 128k by a reloc that\n"
 223                    "                              "
 224                    "  is limited to 128k max, it inserts a jump\n"
 225                    "                              "
 226                    "  stub. You can de-active this with this switch.\n"));
 227   fprintf (file, _("  --debug-stubs               "
 228                    "Used for debugging avr-ld.\n"));
 229   fprintf (file, _("  --debug-relax               "
 230                    "Used for debugging avr-ld.\n"));
 231 '
 232
 233 PARSE_AND_LIST_ARGS_CASES='
 234
 235     case OPTION_PMEM_WRAP_AROUND:
 236       {
 237         /* This variable is defined in the bfd library.  */
 238         if ((!strcmp (optarg,"32k"))      || (!strcmp (optarg,"32K")))
 239           avr_pc_wrap_around = 32768;
 240         else if ((!strcmp (optarg,"8k")) || (!strcmp (optarg,"8K")))
 241           avr_pc_wrap_around = 8192;
 242         else if ((!strcmp (optarg,"16k")) || (!strcmp (optarg,"16K")))
 243           avr_pc_wrap_around = 16384;
 244         else if ((!strcmp (optarg,"64k")) || (!strcmp (optarg,"64K")))
 245           avr_pc_wrap_around = 0x10000;
 246         else
 247           return FALSE;
 248       }
 249       break;
 250
 251     case OPTION_DEBUG_STUBS:
 252       avr_debug_stubs = TRUE;
 253       break;
 254
 255     case OPTION_DEBUG_RELAX:
 256       avr_debug_relax = TRUE;
 257       break;
 258
 259     case OPTION_NO_STUBS:
 260       avr_no_stubs = TRUE;
 261       break;
 262
 263     case OPTION_NO_CALL_RET_REPLACEMENT:
 264       {
 265         /* This variable is defined in the bfd library.  */
 266         avr_replace_call_ret_sequences = FALSE;
 267       }
 268       break;
 269 '
 270
 271 #
 272 # Put these extra avr-elf routines in ld_${EMULATION_NAME}_emulation
 273 #
 274 LDEMUL_BEFORE_PARSE=avr_elf_before_parse
 275 LDEMUL_BEFORE_ALLOCATION=avr_elf_${EMULATION_NAME}_before_allocation
 276 LDEMUL_AFTER_ALLOCATION=avr_elf_after_allocation
 277 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=avr_elf_create_output_section_statements