1llvm-objcopy - object copying and editing tool 2============================================== 3 4.. program:: llvm-objcopy 5 6SYNOPSIS 7-------- 8 9:program:`llvm-objcopy` [*options*] *input* [*output*] 10 11DESCRIPTION 12----------- 13 14:program:`llvm-objcopy` is a tool to copy and manipulate objects. In basic 15usage, it makes a semantic copy of the input to the output. If any options are 16specified, the output may be modified along the way, e.g. by removing sections. 17 18If no output file is specified, the input file is modified in-place. If "-" is 19specified for the input file, the input is read from the program's standard 20input stream. If "-" is specified for the output file, the output is written to 21the standard output stream of the program. 22 23If the input is an archive, any requested operations will be applied to each 24archive member individually. 25 26The tool is still in active development, but in most scenarios it works as a 27drop-in replacement for GNU's :program:`objcopy`. 28 29GENERIC AND CROSS-PLATFORM OPTIONS 30---------------------------------- 31 32The following options are either agnostic of the file format, or apply to 33multiple file formats. 34 35.. option:: --add-gnu-debuglink <debug-file> 36 37 Add a .gnu_debuglink section for ``<debug-file>`` to the output. 38 39.. option:: --add-section <section=file> 40 41 Add a section named ``<section>`` with the contents of ``<file>`` to the 42 output. For ELF objects the section will be of type `SHT_NOTE`, if the name 43 starts with ".note". Otherwise, it will have type `SHT_PROGBITS`. Can be 44 specified multiple times to add multiple sections. 45 46.. option:: --binary-architecture <arch>, -B 47 48 Ignored for compatibility. 49 50.. option:: --disable-deterministic-archives, -U 51 52 Use real values for UIDs, GIDs and timestamps when updating archive member 53 headers. 54 55.. option:: --discard-all, -x 56 57 Remove most local symbols from the output. Different file formats may limit 58 this to a subset of the local symbols. For example, file and section symbols in 59 ELF objects will not be discarded. 60 61.. option:: --enable-deterministic-archives, -D 62 63 Enable deterministic mode when copying archives, i.e. use 0 for archive member 64 header UIDs, GIDs and timestamp fields. On by default. 65 66.. option:: --help, -h 67 68 Print a summary of command line options. 69 70.. option:: --only-section <section>, -j 71 72 Remove all sections from the output, except for sections named ``<section>``. 73 Can be specified multiple times to keep multiple sections. 74 75 For MachO objects, ``<section>`` must be formatted as 76 ``<segment name>,<section name>``. 77 78.. option:: --regex 79 80 If specified, symbol and section names specified by other switches are treated 81 as extended POSIX regular expression patterns. 82 83.. option:: --remove-section <section>, -R 84 85 Remove the specified section from the output. Can be specified multiple times 86 to remove multiple sections simultaneously. 87 88.. option:: --set-section-alignment <section>=<align> 89 90 Set the alignment of section ``<section>`` to `<align>``. Can be specified 91 multiple times to update multiple sections. 92 93.. option:: --strip-all-gnu 94 95 Remove all symbols, debug sections and relocations from the output. This option 96 is equivalent to GNU :program:`objcopy`'s ``--strip-all`` switch. 97 98.. option:: --strip-all, -S 99 100 For ELF objects, remove from the output all symbols and non-alloc sections not 101 within segments, except for .gnu.warning sections and the section name table. 102 103 For COFF objects, remove all symbols, debug sections, and relocations from the 104 output. 105 106.. option:: --strip-debug, -g 107 108 Remove all debug sections from the output. 109 110.. option:: --strip-symbol <symbol>, -N 111 112 Remove all symbols named ``<symbol>`` from the output. Can be specified 113 multiple times to remove multiple symbols. 114 115.. option:: --strip-symbols <filename> 116 117 Remove all symbols whose names appear in the file ``<filename>``, from the 118 output. In the file, each line represents a single symbol name, with leading 119 and trailing whitespace ignored, as is anything following a '#'. Can be 120 specified multiple times to read names from multiple files. 121 122.. option:: --strip-unneeded-symbol <symbol> 123 124 Remove from the output all symbols named ``<symbol>`` that are local or 125 undefined and are not required by any relocation. 126 127.. option:: --strip-unneeded-symbols <filename> 128 129 Remove all symbols whose names appear in the file ``<filename>``, from the 130 output, if they are local or undefined and are not required by any relocation. 131 In the file, each line represents a single symbol name, with leading and 132 trailing whitespace ignored, as is anything following a '#'. Can be specified 133 multiple times to read names from multiple files. 134 135.. option:: --strip-unneeded 136 137 Remove from the output all local or undefined symbols that are not required by 138 relocations. Also remove all debug sections. 139 140.. option:: --version, -V 141 142 Display the version of the :program:`llvm-objcopy` executable. 143 144.. option:: @<FILE> 145 146 Read command-line options and commands from response file `<FILE>`. 147 148.. option:: --wildcard, -w 149 150 Allow wildcard syntax for symbol-related flags. On by default for 151 section-related flags. Incompatible with --regex. 152 153 Wildcard syntax allows the following special symbols: 154 155 ====================== ========================= ================== 156 Character Meaning Equivalent 157 ====================== ========================= ================== 158 ``*`` Any number of characters ``.*`` 159 ``?`` Any single character ``.`` 160 ``\`` Escape the next character ``\`` 161 ``[a-z]`` Character class ``[a-z]`` 162 ``[!a-z]``, ``[^a-z]`` Negated character class ``[^a-z]`` 163 ====================== ========================= ================== 164 165 Additionally, starting a wildcard with '!' will prevent a match, even if 166 another flag matches. For example ``-w -N '*' -N '!x'`` will strip all symbols 167 except for ``x``. 168 169 The order of wildcards does not matter. For example, ``-w -N '*' -N '!x'`` is 170 the same as ``-w -N '!x' -N '*'``. 171 172COFF-SPECIFIC OPTIONS 173--------------------- 174 175The following options are implemented only for COFF objects. If used with other 176objects, :program:`llvm-objcopy` will either emit an error or silently ignore 177them. 178 179.. option:: --only-keep-debug 180 181 Remove the contents of non-debug sections from the output, but keep the section 182 headers. 183 184ELF-SPECIFIC OPTIONS 185-------------------- 186 187The following options are implemented only for ELF objects. If used with other 188objects, :program:`llvm-objcopy` will either emit an error or silently ignore 189them. 190 191.. option:: --add-symbol <name>=[<section>:]<value>[,<flags>] 192 193 Add a new symbol called ``<name>`` to the output symbol table, in the section 194 named ``<section>``, with value ``<value>``. If ``<section>`` is not specified, 195 the symbol is added as an absolute symbol. The ``<flags>`` affect the symbol 196 properties. Accepted values are: 197 198 - `global` = the symbol will have global binding. 199 - `local` = the symbol will have local binding. 200 - `weak` = the symbol will have weak binding. 201 - `default` = the symbol will have default visibility. 202 - `hidden` = the symbol will have hidden visibility. 203 - `protected` = the symbol will have protected visibility. 204 - `file` = the symbol will be an `STT_FILE` symbol. 205 - `section` = the symbol will be an `STT_SECTION` symbol. 206 - `object` = the symbol will be an `STT_OBJECT` symbol. 207 - `function` = the symbol will be an `STT_FUNC` symbol. 208 - `indirect-function` = the symbol will be an `STT_GNU_IFUNC` symbol. 209 210 Additionally, the following flags are accepted but ignored: `debug`, 211 `constructor`, `warning`, `indirect`, `synthetic`, `unique-object`, `before`. 212 213 Can be specified multiple times to add multiple symbols. 214 215.. option:: --allow-broken-links 216 217 Allow :program:`llvm-objcopy` to remove sections even if it would leave invalid 218 section references. Any invalid sh_link fields will be set to zero. 219 220.. option:: --build-id-link-dir <dir> 221 222 Set the directory used by :option:`--build-id-link-input` and 223 :option:`--build-id-link-output`. 224 225.. option:: --build-id-link-input <suffix> 226 227 Hard-link the input to ``<dir>/xx/xxx<suffix>``, where ``<dir>`` is the directory 228 specified by :option:`--build-id-link-dir`. The path used is derived from the 229 hex build ID. 230 231.. option:: --build-id-link-output <suffix> 232 233 Hard-link the output to ``<dir>/xx/xxx<suffix>``, where ``<dir>`` is the directory 234 specified by :option:`--build-id-link-dir`. The path used is derived from the 235 hex build ID. 236 237.. option:: --change-start <incr>, --adjust-start 238 239 Add ``<incr>`` to the program's start address. Can be specified multiple 240 times, in which case the values will be applied cumulatively. 241 242.. option:: --compress-debug-sections [<style>] 243 244 Compress DWARF debug sections in the output, using the specified style. 245 Supported styles are `zlib-gnu` and `zlib`. Defaults to `zlib` if no style is 246 specified. 247 248.. option:: --decompress-debug-sections 249 250 Decompress any compressed DWARF debug sections in the output. 251 252.. option:: --discard-locals, -X 253 254 Remove local symbols starting with ".L" from the output. 255 256.. option:: --dump-section <section>=<file> 257 258 Dump the contents of section ``<section>`` into the file ``<file>``. Can be 259 specified multiple times to dump multiple sections to different files. 260 ``<file>`` is unrelated to the input and output files provided to 261 :program:`llvm-objcopy` and as such the normal copying and editing 262 operations will still be performed. No operations are performed on the sections 263 prior to dumping them. 264 265.. option:: --extract-dwo 266 267 Remove all sections that are not DWARF .dwo sections from the output. 268 269.. option:: --extract-main-partition 270 271 Extract the main partition from the output. 272 273.. option:: --extract-partition <name> 274 275 Extract the named partition from the output. 276 277.. option:: --globalize-symbol <symbol> 278 279 Mark any defined symbols named ``<symbol>`` as global symbols in the output. 280 Can be specified multiple times to mark multiple symbols. 281 282.. option:: --globalize-symbols <filename> 283 284 Read a list of names from the file ``<filename>`` and mark defined symbols with 285 those names as global in the output. In the file, each line represents a single 286 symbol, with leading and trailing whitespace ignored, as is anything following 287 a '#'. Can be specified multiple times to read names from multiple files. 288 289.. option:: --input-target <format>, -I 290 291 Read the input as the specified format. See `SUPPORTED FORMATS`_ for a list of 292 valid ``<format>`` values. If unspecified, :program:`llvm-objcopy` will attempt 293 to determine the format automatically. 294 295.. option:: --keep-file-symbols 296 297 Keep symbols of type `STT_FILE`, even if they would otherwise be stripped. 298 299.. option:: --keep-global-symbol <symbol> 300 301 Make all symbols local in the output, except for symbols with the name 302 ``<symbol>``. Can be specified multiple times to ignore multiple symbols. 303 304.. option:: --keep-global-symbols <filename> 305 306 Make all symbols local in the output, except for symbols named in the file 307 ``<filename>``. In the file, each line represents a single symbol, with leading 308 and trailing whitespace ignored, as is anything following a '#'. Can be 309 specified multiple times to read names from multiple files. 310 311.. option:: --keep-section <section> 312 313 When removing sections from the output, do not remove sections named 314 ``<section>``. Can be specified multiple times to keep multiple sections. 315 316.. option:: --keep-symbol <symbol>, -K 317 318 When removing symbols from the output, do not remove symbols named 319 ``<symbol>``. Can be specified multiple times to keep multiple symbols. 320 321.. option:: --keep-symbols <filename> 322 323 When removing symbols from the output do not remove symbols named in the file 324 ``<filename>``. In the file, each line represents a single symbol, with leading 325 and trailing whitespace ignored, as is anything following a '#'. Can be 326 specified multiple times to read names from multiple files. 327 328.. option:: --localize-hidden 329 330 Make all symbols with hidden or internal visibility local in the output. 331 332.. option:: --localize-symbol <symbol>, -L 333 334 Mark any defined non-common symbol named ``<symbol>`` as a local symbol in the 335 output. Can be specified multiple times to mark multiple symbols as local. 336 337.. option:: --localize-symbols <filename> 338 339 Read a list of names from the file ``<filename>`` and mark defined non-common 340 symbols with those names as local in the output. In the file, each line 341 represents a single symbol, with leading and trailing whitespace ignored, as is 342 anything following a '#'. Can be specified multiple times to read names from 343 multiple files. 344 345.. option:: --new-symbol-visibility <visibility> 346 347 Specify the visibility of the symbols automatically created when using binary 348 input or :option:`--add-symbol`. Valid options are: 349 350 - `default` 351 - `hidden` 352 - `internal` 353 - `protected` 354 355 The default is `default`. 356 357.. option:: --output-target <format>, -O 358 359 Write the output as the specified format. See `SUPPORTED FORMATS`_ for a list 360 of valid ``<format>`` values. If unspecified, the output format is assumed to 361 be the same as the input file's format. 362 363.. option:: --prefix-alloc-sections <prefix> 364 365 Add ``<prefix>`` to the front of the names of all allocatable sections in the 366 output. 367 368.. option:: --prefix-symbols <prefix> 369 370 Add ``<prefix>`` to the front of every symbol name in the output. 371 372.. option:: --preserve-dates, -p 373 374 Preserve access and modification timestamps in the output. 375 376.. option:: --redefine-sym <old>=<new> 377 378 Rename symbols called ``<old>`` to ``<new>`` in the output. Can be specified 379 multiple times to rename multiple symbols. 380 381.. option:: --redefine-syms <filename> 382 383 Rename symbols in the output as described in the file ``<filename>``. In the 384 file, each line represents a single symbol to rename, with the old name and new 385 name separated by an equals sign. Leading and trailing whitespace is ignored, 386 as is anything following a '#'. Can be specified multiple times to read names 387 from multiple files. 388 389.. option:: --rename-section <old>=<new>[,<flag>,...] 390 391 Rename sections called ``<old>`` to ``<new>`` in the output, and apply any 392 specified ``<flag>`` values. See :option:`--set-section-flags` for a list of 393 supported flags. Can be specified multiple times to rename multiple sections. 394 395.. option:: --set-section-flags <section>=<flag>[,<flag>,...] 396 397 Set section properties in the output of section ``<section>`` based on the 398 specified ``<flag>`` values. Can be specified multiple times to update multiple 399 sections. 400 401 Following is a list of supported flags and their effects: 402 403 - `alloc` = add the `SHF_ALLOC` flag. 404 - `load` = if the section has `SHT_NOBITS` type, mark it as a `SHT_PROGBITS` 405 section. 406 - `readonly` = if this flag is not specified, add the `SHF_WRITE` flag. 407 - `code` = add the `SHF_EXECINSTR` flag. 408 - `merge` = add the `SHF_MERGE` flag. 409 - `strings` = add the `SHF_STRINGS` flag. 410 - `contents` = if the section has `SHT_NOBITS` type, mark it as a `SHT_PROGBITS` 411 section. 412 413 The following flags are also accepted, but are ignored for GNU compatibility: 414 `noload`, `debug`, `data`, `rom`, `share`. 415 416.. option:: --set-start-addr <addr> 417 418 Set the start address of the output to ``<addr>``. Overrides any previously 419 specified :option:`--change-start` or :option:`--adjust-start` options. 420 421.. option:: --split-dwo <dwo-file> 422 423 Equivalent to running :program:`llvm-objcopy` with :option:`--extract-dwo` and 424 ``<dwo-file>`` as the output file and no other options, and then with 425 :option:`--strip-dwo` on the input file. 426 427.. option:: --strip-dwo 428 429 Remove all DWARF .dwo sections from the output. 430 431.. option:: --strip-non-alloc 432 433 Remove from the output all non-allocatable sections that are not within 434 segments. 435 436.. option:: --strip-sections 437 438 Remove from the output all section headers and all section data not within 439 segments. Note that many tools will not be able to use an object without 440 section headers. 441 442.. option:: --target <format>, -F 443 444 Equivalent to :option:`--input-target` and :option:`--output-target` for the 445 specified format. See `SUPPORTED FORMATS`_ for a list of valid ``<format>`` 446 values. 447 448.. option:: --weaken-symbol <symbol>, -W 449 450 Mark any global symbol named ``<symbol>`` as a weak symbol in the output. Can 451 be specified multiple times to mark multiple symbols as weak. 452 453.. option:: --weaken-symbols <filename> 454 455 Read a list of names from the file ``<filename>`` and mark global symbols with 456 those names as weak in the output. In the file, each line represents a single 457 symbol, with leading and trailing whitespace ignored, as is anything following 458 a '#'. Can be specified multiple times to read names from multiple files. 459 460.. option:: --weaken 461 462 Mark all defined global symbols as weak in the output. 463 464SUPPORTED FORMATS 465----------------- 466 467The following values are currently supported by :program:`llvm-objcopy` for the 468:option:`--input-target`, :option:`--output-target`, and :option:`--target` 469options. For GNU :program:`objcopy` compatibility, the values are all bfdnames. 470 471- `binary` 472- `ihex` 473- `elf32-i386` 474- `elf32-x86-64` 475- `elf64-x86-64` 476- `elf32-iamcu` 477- `elf32-littlearm` 478- `elf64-aarch64` 479- `elf64-littleaarch64` 480- `elf32-littleriscv` 481- `elf64-littleriscv` 482- `elf32-powerpc` 483- `elf32-powerpcle` 484- `elf64-powerpc` 485- `elf64-powerpcle` 486- `elf32-bigmips` 487- `elf32-ntradbigmips` 488- `elf32-ntradlittlemips` 489- `elf32-tradbigmips` 490- `elf32-tradlittlemips` 491- `elf64-tradbigmips` 492- `elf64-tradlittlemips` 493- `elf32-sparc` 494- `elf32-sparcel` 495 496Additionally, all targets except `binary` and `ihex` can have `-freebsd` as a 497suffix. 498 499BINARY INPUT AND OUTPUT 500----------------------- 501 502If `binary` is used as the value for :option:`--input-target`, the input file 503will be embedded as a data section in an ELF relocatable object, with symbols 504``_binary_<file_name>_start``, ``_binary_<file_name>_end``, and 505``_binary_<file_name>_size`` representing the start, end and size of the data, 506where ``<file_name>`` is the path of the input file as specified on the command 507line with non-alphanumeric characters converted to ``_``. 508 509If `binary` is used as the value for :option:`--output-target`, the output file 510will be a raw binary file, containing the memory image of the input file. 511Symbols and relocation information will be discarded. The image will start at 512the address of the first loadable section in the output. 513 514EXIT STATUS 515----------- 516 517:program:`llvm-objcopy` exits with a non-zero exit code if there is an error. 518Otherwise, it exits with code 0. 519 520BUGS 521---- 522 523To report bugs, please visit <http://llvm.org/bugs/>. 524 525There is a known issue with :option:`--input-target` and :option:`--target` 526causing only ``binary`` and ``ihex`` formats to have any effect. Other values 527will be ignored and :program:`llvm-objcopy` will attempt to guess the input 528format. 529 530SEE ALSO 531-------- 532 533:manpage:`llvm-strip(1)` 534