ld/emultempl/avrelf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2006-2021 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 elf.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 ("${EMULATION_NAME}", "avr6") != 0
  82       && strcmp ("${EMULATION_NAME}", "avrxmega6") != 0
  83       && strcmp ("${EMULATION_NAME}", "avrxmega7") != 0)
  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 (_("%F%P: error: cannot change output format "
 120                "whilst linking %s binaries\n"), "AVR");
 121       return;
 122     }
 123
 124   stub_file = lang_add_input_file ("linker stubs",
 125                                    lang_input_file_is_fake_enum,
 126                                    NULL);
 127
 128   stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
 129   if (stub_file->the_bfd == NULL
 130       || !bfd_set_arch_mach (stub_file->the_bfd,
 131                              bfd_get_arch (link_info.output_bfd),
 132                              bfd_get_mach (link_info.output_bfd)))
 133     {
 134       einfo (_("%X%P: can not create stub BFD: %E\n"));
 135       return;
 136     }
 137
 138   /* Now we add the stub section.  */
 139
 140   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 141            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 142   avr_stub_section = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
 143                                                          ".trampolines",
 144                                                          flags);
 145   if (avr_stub_section == NULL)
 146     goto err_ret;
 147
 148   avr_stub_section->alignment_power = 1;
 149
 150   ldlang_add_file (stub_file);
 151
 152   return;
 153
 154  err_ret:
 155   einfo (_("%X%P: can not make stub section: %E\n"));
 156   return;
 157 }
 158
 159 /* Re-calculates the size of the stubs so that we won't waste space.  */
 160
 161 static void
 162 avr_elf_after_allocation (void)
 163 {
 164   if (!avr_no_stubs && ! RELAXATION_ENABLED)
 165     {
 166       /* If relaxing, elf32_avr_size_stubs will be called from
 167          elf32_avr_relax_section.  */
 168       if (!elf32_avr_size_stubs (link_info.output_bfd, &link_info, TRUE))
 169         einfo (_("%X%P: can not size stub section: %E\n"));
 170     }
 171
 172   gld${EMULATION_NAME}_after_allocation ();
 173
 174   /* Now build the linker stubs.  */
 175   if (!avr_no_stubs)
 176     {
 177       if (!elf32_avr_build_stubs (&link_info))
 178         einfo (_("%X%P: can not build stubs: %E\n"));
 179     }
 180 }
 181
 182 static void
 183 avr_elf_before_parse (void)
 184 {
 185   /* Don't create a demand-paged executable, since this feature isn't
 186      meaningful in AVR. */
 187   config.magic_demand_paged = FALSE;
 188
 189   gld${EMULATION_NAME}_before_parse ();
 190 }
 191
 192 static void
 193 avr_finish (void)
 194 {
 195   bfd *abfd;
 196   bfd_boolean avr_link_relax;
 197
 198   if (bfd_link_relocatable (&link_info))
 199     {
 200       avr_link_relax = TRUE;
 201       for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
 202         {
 203           /* Don't let the linker stubs prevent the final object being
 204              marked as link-relax ready.  */
 205           if ((elf_elfheader (abfd)->e_flags
 206                & EF_AVR_LINKRELAX_PREPARED) == 0
 207               && abfd != stub_file->the_bfd)
 208             {
 209               avr_link_relax = FALSE;
 210               break;
 211             }
 212         }
 213     }
 214   else
 215     {
 216       avr_link_relax = RELAXATION_ENABLED;
 217     }
 218
 219   abfd = link_info.output_bfd;
 220
 221   if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
 222     {
 223       if (avr_link_relax)
 224         elf_elfheader (abfd)->e_flags |= EF_AVR_LINKRELAX_PREPARED;
 225       else
 226         elf_elfheader (abfd)->e_flags &= ~EF_AVR_LINKRELAX_PREPARED;
 227     }
 228
 229   finish_default ();
 230 }
 231 EOF
 232
 233
 234 PARSE_AND_LIST_PROLOGUE='
 235
 236 #define OPTION_NO_CALL_RET_REPLACEMENT 301
 237 #define OPTION_PMEM_WRAP_AROUND        302
 238 #define OPTION_NO_STUBS                303
 239 #define OPTION_DEBUG_STUBS             304
 240 #define OPTION_DEBUG_RELAX             305
 241 '
 242
 243 PARSE_AND_LIST_LONGOPTS='
 244   { "no-call-ret-replacement", no_argument,
 245     NULL, OPTION_NO_CALL_RET_REPLACEMENT},
 246   { "pmem-wrap-around", required_argument,
 247     NULL, OPTION_PMEM_WRAP_AROUND},
 248   { "no-stubs", no_argument,
 249     NULL, OPTION_NO_STUBS},
 250   { "debug-stubs", no_argument,
 251     NULL, OPTION_DEBUG_STUBS},
 252   { "debug-relax", no_argument,
 253     NULL, OPTION_DEBUG_RELAX},
 254 '
 255
 256 PARSE_AND_LIST_OPTIONS='
 257   fprintf (file, _("  --pmem-wrap-around=<val>    "
 258                    "Make the linker relaxation machine assume that a\n"
 259                    "                              "
 260                    "  program counter wrap-around occurs at address\n"
 261                    "                              "
 262                    "  <val>.  Supported values: 8k, 16k, 32k and 64k.\n"));
 263   fprintf (file, _("  --no-call-ret-replacement   "
 264                    "The relaxation machine normally will\n"
 265                    "                              "
 266                    "  substitute two immediately following call/ret\n"
 267                    "                              "
 268                    "  instructions by a single jump instruction.\n"
 269                    "                              "
 270                    "  This option disables this optimization.\n"));
 271   fprintf (file, _("  --no-stubs                  "
 272                    "If the linker detects to attempt to access\n"
 273                    "                              "
 274                    "  an instruction beyond 128k by a reloc that\n"
 275                    "                              "
 276                    "  is limited to 128k max, it inserts a jump\n"
 277                    "                              "
 278                    "  stub. You can de-active this with this switch.\n"));
 279   fprintf (file, _("  --debug-stubs               "
 280                    "Used for debugging avr-ld.\n"));
 281   fprintf (file, _("  --debug-relax               "
 282                    "Used for debugging avr-ld.\n"));
 283 '
 284
 285 PARSE_AND_LIST_ARGS_CASES='
 286
 287     case OPTION_PMEM_WRAP_AROUND:
 288       {
 289         /* This variable is defined in the bfd library.  */
 290         if ((!strcmp (optarg,"32k"))      || (!strcmp (optarg,"32K")))
 291           avr_pc_wrap_around = 32768;
 292         else if ((!strcmp (optarg,"8k"))  || (!strcmp (optarg,"8K")))
 293           avr_pc_wrap_around = 8192;
 294         else if ((!strcmp (optarg,"16k")) || (!strcmp (optarg,"16K")))
 295           avr_pc_wrap_around = 16384;
 296         else if ((!strcmp (optarg,"64k")) || (!strcmp (optarg,"64K")))
 297           avr_pc_wrap_around = 0x10000;
 298         else
 299           return FALSE;
 300       }
 301       break;
 302
 303     case OPTION_DEBUG_STUBS:
 304       avr_debug_stubs = TRUE;
 305       break;
 306
 307     case OPTION_DEBUG_RELAX:
 308       avr_debug_relax = TRUE;
 309       break;
 310
 311     case OPTION_NO_STUBS:
 312       avr_no_stubs = TRUE;
 313       break;
 314
 315     case OPTION_NO_CALL_RET_REPLACEMENT:
 316       {
 317         /* This variable is defined in the bfd library.  */
 318         avr_replace_call_ret_sequences = FALSE;
 319       }
 320       break;
 321 '
 322
 323 #
 324 # Put these extra avr-elf routines in ld_${EMULATION_NAME}_emulation
 325 #
 326 LDEMUL_BEFORE_PARSE=avr_elf_before_parse
 327 LDEMUL_BEFORE_ALLOCATION=avr_elf_${EMULATION_NAME}_before_allocation
 328 LDEMUL_AFTER_ALLOCATION=avr_elf_after_allocation
 329 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=avr_elf_create_output_section_statements
 330 LDEMUL_FINISH=avr_finish