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 For MachO objects, ``<section>`` must be formatted as 47 ``<segment name>,<section name>``. 48 49.. option:: --binary-architecture <arch>, -B 50 51 Ignored for compatibility. 52 53.. option:: --disable-deterministic-archives, -U 54 55 Use real values for UIDs, GIDs and timestamps when updating archive member 56 headers. 57 58.. option:: --discard-all, -x 59 60 Remove most local symbols from the output. Different file formats may limit 61 this to a subset of the local symbols. For example, file and section symbols in 62 ELF objects will not be discarded. Additionally, remove all debug sections. 63 64.. option:: --dump-section <section>=<file> 65 66 Dump the contents of section ``<section>`` into the file ``<file>``. Can be 67 specified multiple times to dump multiple sections to different files. 68 ``<file>`` is unrelated to the input and output files provided to 69 :program:`llvm-objcopy` and as such the normal copying and editing 70 operations will still be performed. No operations are performed on the sections 71 prior to dumping them. 72 73 For MachO objects, ``<section>`` must be formatted as 74 ``<segment name>,<section name>``. 75 76.. option:: --enable-deterministic-archives, -D 77 78 Enable deterministic mode when copying archives, i.e. use 0 for archive member 79 header UIDs, GIDs and timestamp fields. On by default. 80 81.. option:: --globalize-symbol <symbol> 82 83 Mark any defined symbols named ``<symbol>`` as global symbols in the output. 84 Can be specified multiple times to mark multiple symbols. 85 86.. option:: --globalize-symbols <filename> 87 88 Read a list of names from the file ``<filename>`` and mark defined symbols with 89 those names as global in the output. In the file, each line represents a single 90 symbol, with leading and trailing whitespace ignored, as is anything following 91 a '#'. Can be specified multiple times to read names from multiple files. 92 93.. option:: --help, -h 94 95 Print a summary of command line options. 96 97.. option:: --keep-global-symbol <symbol>, -G 98 99 Mark all symbols local in the output, except for symbols with the name 100 ``<symbol>``. Can be specified multiple times to ignore multiple symbols. 101 102.. option:: --keep-global-symbols <filename> 103 104 Mark all symbols local in the output, except for symbols named in the file 105 ``<filename>``. In the file, each line represents a single symbol, with leading 106 and trailing whitespace ignored, as is anything following a '#'. Can be 107 specified multiple times to read names from multiple files. 108 109.. option:: --localize-symbol <symbol>, -L 110 111 Mark any defined non-common symbol named ``<symbol>`` as a local symbol in the 112 output. Can be specified multiple times to mark multiple symbols as local. 113 114.. option:: --localize-symbols <filename> 115 116 Read a list of names from the file ``<filename>`` and mark defined non-common 117 symbols with those names as local in the output. In the file, each line 118 represents a single symbol, with leading and trailing whitespace ignored, as is 119 anything following a '#'. Can be specified multiple times to read names from 120 multiple files. 121 122.. option:: --only-keep-debug 123 124 Produce a debug file as the output that only preserves contents of sections 125 useful for debugging purposes. 126 127 For ELF objects, this removes the contents of `SHF_ALLOC` sections that are not 128 `SHT_NOTE` by making them `SHT_NOBITS` and shrinking the program headers where 129 possible. 130 131.. option:: --only-section <section>, -j 132 133 Remove all sections from the output, except for sections named ``<section>``. 134 Can be specified multiple times to keep multiple sections. 135 136 For MachO objects, ``<section>`` must be formatted as 137 ``<segment name>,<section name>``. 138 139.. option:: --redefine-sym <old>=<new> 140 141 Rename symbols called ``<old>`` to ``<new>`` in the output. Can be specified 142 multiple times to rename multiple symbols. 143 144.. option:: --redefine-syms <filename> 145 146 Rename symbols in the output as described in the file ``<filename>``. In the 147 file, each line represents a single symbol to rename, with the old name and new 148 name separated by whitespace. Leading and trailing whitespace is ignored, as is 149 anything following a '#'. Can be specified multiple times to read names from 150 multiple files. 151 152.. option:: --regex 153 154 If specified, symbol and section names specified by other switches are treated 155 as extended POSIX regular expression patterns. 156 157.. option:: --remove-symbol-prefix <prefix> 158 159 Remove ``<prefix>`` from the start of every symbol name. No-op for symbols that do 160 not start with ``<prefix>``. 161 162.. option:: --remove-section <section>, -R 163 164 Remove the specified section from the output. Can be specified multiple times 165 to remove multiple sections simultaneously. 166 167 For MachO objects, ``<section>`` must be formatted as 168 ``<segment name>,<section name>``. 169 170.. option:: --set-section-alignment <section>=<align> 171 172 Set the alignment of section ``<section>`` to ``<align>``. Can be specified 173 multiple times to update multiple sections. 174 175.. option:: --set-section-flags <section>=<flag>[,<flag>,...] 176 177 Set section properties in the output of section ``<section>`` based on the 178 specified ``<flag>`` values. Can be specified multiple times to update multiple 179 sections. 180 181 Supported flag names are `alloc`, `load`, `noload`, `readonly`, `exclude`, 182 `debug`, `code`, `data`, `rom`, `share`, `contents`, `merge`, `strings`, and 183 `large`. Not all flags are meaningful for all object file formats or target 184 architectures. 185 186 For ELF objects, the flags have the following effects: 187 188 - `alloc` = add the `SHF_ALLOC` flag. 189 - `load` = if the section has `SHT_NOBITS` type, mark it as a `SHT_PROGBITS` 190 section. 191 - `readonly` = if this flag is not specified, add the `SHF_WRITE` flag. 192 - `exclude` = add the `SHF_EXCLUDE` flag. 193 - `code` = add the `SHF_EXECINSTR` flag. 194 - `merge` = add the `SHF_MERGE` flag. 195 - `strings` = add the `SHF_STRINGS` flag. 196 - `contents` = if the section has `SHT_NOBITS` type, mark it as a `SHT_PROGBITS` 197 section. 198 - `large` = add the `SHF_X86_64_LARGE` on x86_64; rejected if the target 199 architecture is not x86_64. 200 201 For COFF objects, the flags have the following effects: 202 203 - `alloc` = add the `IMAGE_SCN_CNT_UNINITIALIZED_DATA` and `IMAGE_SCN_MEM_READ` 204 flags, unless the `load` flag is specified. 205 - `noload` = add the `IMAGE_SCN_LNK_REMOVE` and `IMAGE_SCN_MEM_READ` flags. 206 - `readonly` = if this flag is not specified, add the `IMAGE_SCN_MEM_WRITE` 207 flag. 208 - `exclude` = add the `IMAGE_SCN_LNK_REMOVE` and `IMAGE_SCN_MEM_READ` flags. 209 - `debug` = add the `IMAGE_SCN_CNT_INITIALIZED_DATA`, 210 `IMAGE_SCN_MEM_DISCARDABLE` and `IMAGE_SCN_MEM_READ` flags. 211 - `code` = add the `IMAGE_SCN_CNT_CODE`, `IMAGE_SCN_MEM_EXECUTE` and 212 `IMAGE_SCN_MEM_READ` flags. 213 - `data` = add the `IMAGE_SCN_CNT_INITIALIZED_DATA` and `IMAGE_SCN_MEM_READ` 214 flags. 215 - `share` = add the `IMAGE_SCN_MEM_SHARED` and `IMAGE_SCN_MEM_READ` flags. 216 217.. option:: --skip-symbol <symbol> 218 219 Do not change the parameters of symbol ``<symbol>`` when executing other 220 options that can change the symbol's name, binding or visibility. 221 222.. option:: --skip-symbols <filename> 223 224 Do not change the parameters of symbols named in the file ``<filename>`` when 225 executing other options that can change the symbol's name, binding or 226 visibility. In the file, each line represents a single symbol, with leading 227 and trailing whitespace ignored, as is anything following a '#'. 228 Can be specified multiple times to read names from multiple files. 229 230.. option:: --strip-all-gnu 231 232 Remove all symbols, debug sections and relocations from the output. This option 233 is equivalent to GNU :program:`objcopy`'s ``--strip-all`` switch. 234 235.. option:: --strip-all, -S 236 237 For ELF objects, remove from the output all symbols and non-alloc sections not 238 within segments, except for .gnu.warning, .ARM.attribute sections and the 239 section name table. 240 241 For COFF and Mach-O objects, remove all symbols, debug sections, and 242 relocations from the output. 243 244.. option:: --strip-debug, -g 245 246 Remove all debug sections from the output. 247 248.. option:: --strip-symbol <symbol>, -N 249 250 Remove all symbols named ``<symbol>`` from the output. Can be specified 251 multiple times to remove multiple symbols. 252 253.. option:: --strip-symbols <filename> 254 255 Remove all symbols whose names appear in the file ``<filename>``, from the 256 output. In the file, each line represents a single symbol name, with leading 257 and trailing whitespace ignored, as is anything following a '#'. Can be 258 specified multiple times to read names from multiple files. 259 260.. option:: --strip-unneeded-symbol <symbol> 261 262 Remove from the output all symbols named ``<symbol>`` that are local or 263 undefined and are not required by any relocation. 264 265.. option:: --strip-unneeded-symbols <filename> 266 267 Remove all symbols whose names appear in the file ``<filename>``, from the 268 output, if they are local or undefined and are not required by any relocation. 269 In the file, each line represents a single symbol name, with leading and 270 trailing whitespace ignored, as is anything following a '#'. Can be specified 271 multiple times to read names from multiple files. 272 273.. option:: --strip-unneeded 274 275 Remove from the output all local or undefined symbols that are not required by 276 relocations. Also remove all debug sections. 277 278.. option:: --update-section <name>=<file> 279 280 Replace the contents of the section ``<name>`` with contents from the file 281 ``<file>``. If the section ``<name>`` is part of a segment, the new contents 282 cannot be larger than the existing section. 283 284.. option:: --version, -V 285 286 Display the version of the :program:`llvm-objcopy` executable. 287 288.. option:: --wildcard, -w 289 290 Allow wildcard syntax for symbol-related flags. On by default for 291 section-related flags. Incompatible with --regex. 292 293 Wildcard syntax allows the following special symbols: 294 295 ====================== ========================= ================== 296 Character Meaning Equivalent 297 ====================== ========================= ================== 298 ``*`` Any number of characters ``.*`` 299 ``?`` Any single character ``.`` 300 ``\`` Escape the next character ``\`` 301 ``[a-z]`` Character class ``[a-z]`` 302 ``[!a-z]``, ``[^a-z]`` Negated character class ``[^a-z]`` 303 ====================== ========================= ================== 304 305 Additionally, starting a wildcard with '!' will prevent a match, even if 306 another flag matches. For example ``-w -N '*' -N '!x'`` will strip all symbols 307 except for ``x``. 308 309 The order of wildcards does not matter. For example, ``-w -N '*' -N '!x'`` is 310 the same as ``-w -N '!x' -N '*'``. 311 312.. option:: @<FILE> 313 314 Read command-line options and commands from response file `<FILE>`. 315 316ELF-SPECIFIC OPTIONS 317-------------------- 318 319The following options are implemented only for ELF objects. If used with other 320objects, :program:`llvm-objcopy` will either emit an error or silently ignore 321them. 322 323.. option:: --add-symbol <name>=[<section>:]<value>[,<flags>] 324 325 Add a new symbol called ``<name>`` to the output symbol table, in the section 326 named ``<section>``, with value ``<value>``. If ``<section>`` is not specified, 327 the symbol is added as an absolute symbol. The ``<flags>`` affect the symbol 328 properties. Accepted values are: 329 330 - `global` = the symbol will have global binding. 331 - `local` = the symbol will have local binding. 332 - `weak` = the symbol will have weak binding. 333 - `default` = the symbol will have default visibility. 334 - `hidden` = the symbol will have hidden visibility. 335 - `protected` = the symbol will have protected visibility. 336 - `file` = the symbol will be an `STT_FILE` symbol. 337 - `section` = the symbol will be an `STT_SECTION` symbol. 338 - `object` = the symbol will be an `STT_OBJECT` symbol. 339 - `function` = the symbol will be an `STT_FUNC` symbol. 340 - `indirect-function` = the symbol will be an `STT_GNU_IFUNC` symbol. 341 342 Additionally, the following flags are accepted but ignored: `debug`, 343 `constructor`, `warning`, `indirect`, `synthetic`, `unique-object`, `before`. 344 345 Can be specified multiple times to add multiple symbols. 346 347.. option:: --allow-broken-links 348 349 Allow :program:`llvm-objcopy` to remove sections even if it would leave invalid 350 section references. Any invalid sh_link fields will be set to zero. 351 352.. option:: --change-section-lma \*{+-}<val> 353 354 Shift LMA of non-zero-sized segments by ``<val>``. 355 356.. option:: --change-section-address <section>{=+-}<val>, --adjust-section-vma 357 358 Change the address of sections that match ``<section>`` pattern to the 359 specified value, or apply ``+<val>``/``-<val>`` to the current value. Can be 360 specified multiple times to specify multiple patterns. Each section is only 361 modified by one ``--change-section-address`` argument. If a section name 362 matches multiple patterns, the rightmost change applies. The object file needs 363 to be of ET_REL type. 364 365.. option:: --change-start <incr>, --adjust-start 366 367 Add ``<incr>`` to the program's start address. Can be specified multiple 368 times, in which case the values will be applied cumulatively. 369 370.. option:: --compress-debug-sections [<format>] 371 372 Compress DWARF debug sections in the output, using the specified format. 373 Supported formats are ``zlib`` and ``zstd``. Use ``zlib`` if ``<format>`` is omitted. 374 375.. option:: --compress-sections <section>=<format> 376 377 Compress or decompress sections matched by ``<section>`` using the specified 378 format. Supported formats are ``zlib`` and ``zstd``. Specify ``none`` for 379 decompression. When a section is matched by multiple options, the last one 380 wins. A wildcard ``<section>`` starting with '!' is disallowed. 381 Sections within a segment cannot be (de)compressed. 382 383.. option:: --decompress-debug-sections 384 385 Decompress any compressed DWARF debug sections in the output. 386 387.. option:: --discard-locals, -X 388 389 Remove local symbols starting with ".L" from the output. 390 391.. option:: --extract-dwo 392 393 Remove all sections that are not DWARF .dwo sections from the output. 394 395.. option:: --extract-main-partition 396 397 Extract the main partition from the output. 398 399.. option:: --extract-partition <name> 400 401 Extract the named partition from the output. 402 403.. option:: --gap-fill <value> 404 405 For binary outputs, fill the gaps between sections with ``<value>`` instead 406 of zero. The value must be an unsigned 8-bit integer. 407 408.. option:: --input-target <format>, -I 409 410 Read the input as the specified format. See `SUPPORTED FORMATS`_ for a list of 411 valid ``<format>`` values. If unspecified, :program:`llvm-objcopy` will attempt 412 to determine the format automatically. 413 414.. option:: --keep-file-symbols 415 416 Keep symbols of type `STT_FILE`, even if they would otherwise be stripped. 417 418.. option:: --keep-section <section> 419 420 When removing sections from the output, do not remove sections named 421 ``<section>``. Can be specified multiple times to keep multiple sections. 422 423.. option:: --keep-symbol <symbol>, -K 424 425 When removing symbols from the output, do not remove symbols named 426 ``<symbol>``. Can be specified multiple times to keep multiple symbols. 427 428.. option:: --keep-symbols <filename> 429 430 When removing symbols from the output do not remove symbols named in the file 431 ``<filename>``. In the file, each line represents a single symbol, with leading 432 and trailing whitespace ignored, as is anything following a '#'. Can be 433 specified multiple times to read names from multiple files. 434 435.. option:: --localize-hidden 436 437 Mark all symbols with hidden or internal visibility local in the output. 438 439.. option:: --new-symbol-visibility <visibility> 440 441 Specify the visibility of the symbols automatically created when using binary 442 input or :option:`--add-symbol`. Valid options are: 443 444 - `default` 445 - `hidden` 446 - `internal` 447 - `protected` 448 449 The default is `default`. 450 451.. option:: --no-verify-note-sections 452 453 When adding note sections, do not verify if the section format is valid. 454 455.. option:: --output-target <format>, -O 456 457 Write the output as the specified format. See `SUPPORTED FORMATS`_ for a list 458 of valid ``<format>`` values. If unspecified, the output format is assumed to 459 be the same as the value specified for :option:`--input-target` or the input 460 file's format if that option is also unspecified. 461 462.. option:: --pad-to <address> 463 464 For binary outputs, pad the output to the load address ``<address>`` using a value 465 of zero or the value specified by :option:`--gap-fill`. 466 467.. option:: --prefix-alloc-sections <prefix> 468 469 Add ``<prefix>`` to the front of the names of all allocatable sections in the 470 output. 471 472.. option:: --prefix-symbols <prefix> 473 474 Add ``<prefix>`` to the front of every symbol name in the output. 475 476.. option:: --preserve-dates, -p 477 478 Preserve access and modification timestamps in the output. 479 480.. option:: --remove-note [<name>/]<type> 481 482 Remove notes of integer type ``<type>`` and name ``<name>`` from SHT_NOTE 483 sections that are not in a segment. Can be specified multiple times. 484 485.. option:: --rename-section <old>=<new>[,<flag>,...] 486 487 Rename sections called ``<old>`` to ``<new>`` in the output, and apply any 488 specified ``<flag>`` values. See :option:`--set-section-flags` for a list of 489 supported flags. Can be specified multiple times to rename multiple sections. 490 491.. option:: --set-section-type <section>=<type> 492 493 Set the type of section ``<section>`` to the integer ``<type>``. Can be 494 specified multiple times to update multiple sections. 495 496.. option:: --set-start <addr> 497 498 Set the start address of the output to ``<addr>``. Overrides any previously 499 specified :option:`--change-start` or :option:`--adjust-start` options. 500 501.. option:: --set-symbol-visibility <symbol>=<visibility> 502 503 Change the visibility of a symbol to the specified value. 504 505.. option:: --set-symbols-visibility <filename>=<visibility> 506 507 Read a list of symbols from <filename> and change their visibility to the 508 specified value. Visibility values: default, internal, hidden, protected. 509 510.. option:: --split-dwo <dwo-file> 511 512 Equivalent to running :program:`llvm-objcopy` with :option:`--extract-dwo` and 513 ``<dwo-file>`` as the output file and no other options, and then with 514 :option:`--strip-dwo` on the input file. 515 516.. option:: --strip-dwo 517 518 Remove all DWARF .dwo sections from the output. 519 520.. option:: --strip-non-alloc 521 522 Remove from the output all non-allocatable sections that are not within 523 segments. 524 525.. option:: --strip-sections 526 527 Remove from the output all section headers and all section data not within 528 segments. Note that many tools will not be able to use an object without 529 section headers. 530 531.. option:: --target <format>, -F 532 533 Equivalent to :option:`--input-target` and :option:`--output-target` for the 534 specified format. See `SUPPORTED FORMATS`_ for a list of valid ``<format>`` 535 values. 536 537.. option:: --verify-note-sections 538 539 When adding note sections, verify if the section format is valid. On by 540 default. 541 542.. option:: --weaken-symbol <symbol>, -W 543 544 Mark global symbols named ``<symbol>`` as weak symbols in the output. Can 545 be specified multiple times to mark multiple symbols as weak. 546 547.. option:: --weaken-symbols <filename> 548 549 Read a list of names from the file ``<filename>`` and mark global symbols with 550 those names as weak in the output. In the file, each line represents a single 551 symbol, with leading and trailing whitespace ignored, as is anything following 552 a '#'. Can be specified multiple times to read names from multiple files. 553 554.. option:: --weaken 555 556 Mark all defined global symbols as weak in the output. 557 558MACH-O-SPECIFIC OPTIONS 559----------------------- 560 561.. option:: --keep-undefined 562 563 Keep undefined symbols, even if they would otherwise be stripped. 564 565COFF-SPECIFIC OPTIONS 566--------------------- 567 568.. option:: --subsystem <name>[:<version>] 569 570 Set the PE subsystem, and optionally subsystem version. 571 572SUPPORTED FORMATS 573----------------- 574 575The following values are currently supported by :program:`llvm-objcopy` for the 576:option:`--input-target`, :option:`--output-target`, and :option:`--target` 577options. For GNU :program:`objcopy` compatibility, the values are all bfdnames. 578 579- `binary` 580- `ihex` 581- `elf32-i386` 582- `elf32-x86-64` 583- `elf64-x86-64` 584- `elf32-iamcu` 585- `elf32-littlearm` 586- `elf64-aarch64` 587- `elf64-littleaarch64` 588- `elf32-littleriscv` 589- `elf64-littleriscv` 590- `elf32-powerpc` 591- `elf32-powerpcle` 592- `elf64-powerpc` 593- `elf64-powerpcle` 594- `elf32-bigmips` 595- `elf32-ntradbigmips` 596- `elf32-ntradlittlemips` 597- `elf32-tradbigmips` 598- `elf32-tradlittlemips` 599- `elf64-tradbigmips` 600- `elf64-tradlittlemips` 601- `elf32-sparc` 602- `elf32-sparcel` 603- `elf32-hexagon` 604- `elf32-loongarch` 605- `elf64-loongarch` 606- `elf64-s390` 607 608The following formats are suppoprted by :program:`llvm-objcopy` for the 609:option:`--output-target` only: 610 611- `srec` 612 613Additionally, all targets except `binary`, `ihex`, and `srec` can have 614`-freebsd` as a suffix. 615 616BINARY INPUT AND OUTPUT 617----------------------- 618 619If `binary` is used as the value for :option:`--input-target`, the input file 620will be embedded as a data section in an ELF relocatable object, with symbols 621``_binary_<file_name>_start``, ``_binary_<file_name>_end``, and 622``_binary_<file_name>_size`` representing the start, end and size of the data, 623where ``<file_name>`` is the path of the input file as specified on the command 624line with non-alphanumeric characters converted to ``_``. 625 626If `binary` is used as the value for :option:`--output-target`, the output file 627will be a raw binary file, containing the memory image of the input file. 628Symbols and relocation information will be discarded. The image will start at 629the address of the first loadable section in the output. 630 631EXIT STATUS 632----------- 633 634:program:`llvm-objcopy` exits with a non-zero exit code if there is an error. 635Otherwise, it exits with code 0. 636 637BUGS 638---- 639 640To report bugs, please visit <https://github.com/llvm/llvm-project/labels/tools:llvm-objcopy/strip/>. 641 642There is a known issue with :option:`--input-target` and :option:`--target` 643causing only ``binary`` and ``ihex`` formats to have any effect. Other values 644will be ignored and :program:`llvm-objcopy` will attempt to guess the input 645format. 646 647SEE ALSO 648-------- 649 650:manpage:`llvm-strip(1)` 651