1# This shell script emits a C file. -*- C -*- 2# Copyright (C) 2006-2022 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 27fragment <<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 36static lang_input_statement_type *stub_file; 37static 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 42static bool avr_no_stubs = false; 43static bool avr_debug_relax = false; 44static bool avr_debug_stubs = false; 45static bool avr_replace_call_ret_sequences = true; 46static bfd_vma avr_pc_wrap_around = 0x10000000; 47 48/* Transfers information to the bfd frontend. */ 49 50static void 51avr_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 67static void 68avr_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 112static void 113avr_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 stub_file->the_bfd->flags |= BFD_LINKER_CREATED; 138 139 /* Now we add the stub section. */ 140 141 flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE 142 | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP); 143 avr_stub_section = bfd_make_section_anyway_with_flags (stub_file->the_bfd, 144 ".trampolines", 145 flags); 146 if (avr_stub_section == NULL) 147 goto err_ret; 148 149 avr_stub_section->alignment_power = 1; 150 151 ldlang_add_file (stub_file); 152 153 return; 154 155 err_ret: 156 einfo (_("%X%P: can not make stub section: %E\n")); 157 return; 158} 159 160/* Re-calculates the size of the stubs so that we won't waste space. */ 161 162static void 163avr_elf_after_allocation (void) 164{ 165 if (!avr_no_stubs && ! RELAXATION_ENABLED) 166 { 167 /* If relaxing, elf32_avr_size_stubs will be called from 168 elf32_avr_relax_section. */ 169 if (!elf32_avr_size_stubs (link_info.output_bfd, &link_info, true)) 170 einfo (_("%X%P: can not size stub section: %E\n")); 171 } 172 173 gld${EMULATION_NAME}_after_allocation (); 174 175 /* Now build the linker stubs. */ 176 if (!avr_no_stubs) 177 { 178 if (!elf32_avr_build_stubs (&link_info)) 179 einfo (_("%X%P: can not build stubs: %E\n")); 180 } 181} 182 183static void 184avr_elf_before_parse (void) 185{ 186 /* Don't create a demand-paged executable, since this feature isn't 187 meaningful in AVR. */ 188 config.magic_demand_paged = false; 189 190 gld${EMULATION_NAME}_before_parse (); 191} 192 193static void 194avr_finish (void) 195{ 196 bfd *abfd; 197 bool avr_link_relax; 198 199 if (bfd_link_relocatable (&link_info)) 200 { 201 avr_link_relax = true; 202 for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next) 203 { 204 /* Don't let the linker stubs prevent the final object being 205 marked as link-relax ready. */ 206 if ((elf_elfheader (abfd)->e_flags 207 & EF_AVR_LINKRELAX_PREPARED) == 0 208 && abfd != stub_file->the_bfd) 209 { 210 avr_link_relax = false; 211 break; 212 } 213 } 214 } 215 else 216 { 217 avr_link_relax = RELAXATION_ENABLED; 218 } 219 220 abfd = link_info.output_bfd; 221 222 if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour) 223 { 224 if (avr_link_relax) 225 elf_elfheader (abfd)->e_flags |= EF_AVR_LINKRELAX_PREPARED; 226 else 227 elf_elfheader (abfd)->e_flags &= ~EF_AVR_LINKRELAX_PREPARED; 228 } 229 230 finish_default (); 231} 232EOF 233 234 235PARSE_AND_LIST_PROLOGUE=' 236 237#define OPTION_NO_CALL_RET_REPLACEMENT 301 238#define OPTION_PMEM_WRAP_AROUND 302 239#define OPTION_NO_STUBS 303 240#define OPTION_DEBUG_STUBS 304 241#define OPTION_DEBUG_RELAX 305 242' 243 244PARSE_AND_LIST_LONGOPTS=' 245 { "no-call-ret-replacement", no_argument, 246 NULL, OPTION_NO_CALL_RET_REPLACEMENT}, 247 { "pmem-wrap-around", required_argument, 248 NULL, OPTION_PMEM_WRAP_AROUND}, 249 { "no-stubs", no_argument, 250 NULL, OPTION_NO_STUBS}, 251 { "debug-stubs", no_argument, 252 NULL, OPTION_DEBUG_STUBS}, 253 { "debug-relax", no_argument, 254 NULL, OPTION_DEBUG_RELAX}, 255' 256 257PARSE_AND_LIST_OPTIONS=' 258 fprintf (file, _(" --pmem-wrap-around=<val> " 259 "Make the linker relaxation machine assume that a\n" 260 " " 261 " program counter wrap-around occurs at address\n" 262 " " 263 " <val>. Supported values: 8k, 16k, 32k and 64k.\n")); 264 fprintf (file, _(" --no-call-ret-replacement " 265 "The relaxation machine normally will\n" 266 " " 267 " substitute two immediately following call/ret\n" 268 " " 269 " instructions by a single jump instruction.\n" 270 " " 271 " This option disables this optimization.\n")); 272 fprintf (file, _(" --no-stubs " 273 "If the linker detects to attempt to access\n" 274 " " 275 " an instruction beyond 128k by a reloc that\n" 276 " " 277 " is limited to 128k max, it inserts a jump\n" 278 " " 279 " stub. You can de-active this with this switch.\n")); 280 fprintf (file, _(" --debug-stubs " 281 "Used for debugging avr-ld.\n")); 282 fprintf (file, _(" --debug-relax " 283 "Used for debugging avr-ld.\n")); 284' 285 286PARSE_AND_LIST_ARGS_CASES=' 287 288 case OPTION_PMEM_WRAP_AROUND: 289 { 290 /* This variable is defined in the bfd library. */ 291 if ((!strcmp (optarg,"32k")) || (!strcmp (optarg,"32K"))) 292 avr_pc_wrap_around = 32768; 293 else if ((!strcmp (optarg,"8k")) || (!strcmp (optarg,"8K"))) 294 avr_pc_wrap_around = 8192; 295 else if ((!strcmp (optarg,"16k")) || (!strcmp (optarg,"16K"))) 296 avr_pc_wrap_around = 16384; 297 else if ((!strcmp (optarg,"64k")) || (!strcmp (optarg,"64K"))) 298 avr_pc_wrap_around = 0x10000; 299 else 300 return false; 301 } 302 break; 303 304 case OPTION_DEBUG_STUBS: 305 avr_debug_stubs = true; 306 break; 307 308 case OPTION_DEBUG_RELAX: 309 avr_debug_relax = true; 310 break; 311 312 case OPTION_NO_STUBS: 313 avr_no_stubs = true; 314 break; 315 316 case OPTION_NO_CALL_RET_REPLACEMENT: 317 { 318 /* This variable is defined in the bfd library. */ 319 avr_replace_call_ret_sequences = false; 320 } 321 break; 322' 323 324# 325# Put these extra avr-elf routines in ld_${EMULATION_NAME}_emulation 326# 327LDEMUL_BEFORE_PARSE=avr_elf_before_parse 328LDEMUL_BEFORE_ALLOCATION=avr_elf_${EMULATION_NAME}_before_allocation 329LDEMUL_AFTER_ALLOCATION=avr_elf_after_allocation 330LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=avr_elf_create_output_section_statements 331LDEMUL_FINISH=avr_finish 332