1# This shell script emits a C file. -*- C -*- 2# Copyright (C) 2006-2020 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 bfd_boolean avr_no_stubs = FALSE; 43static bfd_boolean avr_debug_relax = FALSE; 44static bfd_boolean avr_debug_stubs = FALSE; 45static bfd_boolean 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 } 137 138 /* 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 161static void 162avr_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 182static void 183avr_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 192static void 193avr_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} 231EOF 232 233 234PARSE_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 243PARSE_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 256PARSE_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 285PARSE_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# 326LDEMUL_BEFORE_PARSE=avr_elf_before_parse 327LDEMUL_BEFORE_ALLOCATION=avr_elf_${EMULATION_NAME}_before_allocation 328LDEMUL_AFTER_ALLOCATION=avr_elf_after_allocation 329LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=avr_elf_create_output_section_statements 330LDEMUL_FINISH=avr_finish 331