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