1LLVM-OBJCOPY(1) LLVM LLVM-OBJCOPY(1)
2
6 llvm-objcopy - object copying and editing tool
7
9 llvm-objcopy [options] input [output]
10
12 llvm-objcopy is a tool to copy and manipulate objects. In basic usage,
13 it makes a semantic copy of the input to the output. If any options are
14 specified, the output may be modified along the way, e.g. by removing
15 sections.
16 If no output file is specified, the input file is modified in-place. If
18 "-" is specified for the input file, the input is read from the pro‐
19 gram's standard input stream. If "-" is specified for the output file,
20 the output is written to the standard output stream of the program.
21 If the input is an archive, any requested operations will be applied to
23 each archive member individually.
24 The tool is still in active development, but in most scenarios it works
26 as a drop-in replacement for GNU's objcopy.
27
29 The following options are either agnostic of the file format, or apply
30 to multiple file formats.
31 --add-gnu-debuglink <debug-file>
33 Add a .gnu_debuglink section for <debug-file> to the output.
34 --add-section <section=file>
36 Add a section named <section> with the contents of <file> to the
37 output. For ELF objects the section will be of type SHT_NOTE, if
38 the name starts with ".note". Otherwise, it will have type
39 SHT_PROGBITS. Can be specified multiple times to add multiple
40 sections.
41 For MachO objects, <section> must be formatted as <segment
43 name>,<section name>.
44 --binary-architecture <arch>, -B
46 Ignored for compatibility.
47 --disable-deterministic-archives, -U
49 Use real values for UIDs, GIDs and timestamps when updating ar‐
50 chive member headers.
51 --discard-all, -x
53 Remove most local symbols from the output. Different file for‐
54 mats may limit this to a subset of the local symbols. For exam‐
55 ple, file and section symbols in ELF objects will not be dis‐
56 carded.
57 --dump-section <section>=<file>
59 Dump the contents of section <section> into the file <file>. Can
60 be specified multiple times to dump multiple sections to differ‐
61 ent files. <file> is unrelated to the input and output files
62 provided to llvm-objcopy and as such the normal copying and
63 editing operations will still be performed. No operations are
64 performed on the sections prior to dumping them.
65 For MachO objects, <section> must be formatted as <segment
67 name>,<section name>.
68 --enable-deterministic-archives, -D
70 Enable deterministic mode when copying archives, i.e. use 0 for
71 archive member header UIDs, GIDs and timestamp fields. On by de‐
72 fault.
73 --help, -h
75 Print a summary of command line options.
76 --only-keep-debug
78 Produce a debug file as the output that only preserves contents
79 of sections useful for debugging purposes.
80 For ELF objects, this removes the contents of SHF_ALLOC sections
82 that are not SHT_NOTE by making them SHT_NOBITS and shrinking
83 the program headers where possible.
84 --only-section <section>, -j
86 Remove all sections from the output, except for sections named
87 <section>. Can be specified multiple times to keep multiple
88 sections.
89 For MachO objects, <section> must be formatted as <segment
91 name>,<section name>.
92 --redefine-sym <old>=<new>
94 Rename symbols called <old> to <new> in the output. Can be spec‐
95 ified multiple times to rename multiple symbols.
96 --redefine-syms <filename>
98 Rename symbols in the output as described in the file <file‐
99 name>. In the file, each line represents a single symbol to re‐
100 name, with the old name and new name separated by whitespace.
101 Leading and trailing whitespace is ignored, as is anything fol‐
102 lowing a '#'. Can be specified multiple times to read names from
103 multiple files.
104 --regex
106 If specified, symbol and section names specified by other
107 switches are treated as extended POSIX regular expression pat‐
108 terns.
109 --remove-section <section>, -R
111 Remove the specified section from the output. Can be specified
112 multiple times to remove multiple sections simultaneously.
113 For MachO objects, <section> must be formatted as <segment
115 name>,<section name>.
116 --set-section-alignment <section>=<align>
118 Set the alignment of section <section> to <align>`. Can be spec‐
119 ified multiple times to update multiple sections.
120 --set-section-flags <section>=<flag>[,<flag>,...]
122 Set section properties in the output of section <section> based
123 on the specified <flag> values. Can be specified multiple times
124 to update multiple sections.
125 Supported flag names are alloc, load, noload, readonly, exclude,
127 debug, code, data, rom, share, contents, merge and strings. Not
128 all flags are meaningful for all object file formats.
129 For ELF objects, the flags have the following effects:
131 • alloc = add the SHF_ALLOC flag.
133 • load = if the section has SHT_NOBITS type, mark it as a
135 SHT_PROGBITS section.
136 • readonly = if this flag is not specified, add the SHF_WRITE
138 flag.
139 • exclude = add the SHF_EXCLUDE flag.
141 • code = add the SHF_EXECINSTR flag.
143 • merge = add the SHF_MERGE flag.
145 • strings = add the SHF_STRINGS flag.
147 • contents = if the section has SHT_NOBITS type, mark it as a
149 SHT_PROGBITS section.
150 For COFF objects, the flags have the following effects:
152 • alloc = add the IMAGE_SCN_CNT_UNINITIALIZED_DATA and IM‐
154 AGE_SCN_MEM_READ flags, unless the load flag is specified.
155 • noload = add the IMAGE_SCN_LNK_REMOVE and IMAGE_SCN_MEM_READ
157 flags.
158 • readonly = if this flag is not specified, add the IM‐
160 AGE_SCN_MEM_WRITE flag.
161 • exclude = add the IMAGE_SCN_LNK_REMOVE and IMAGE_SCN_MEM_READ
163 flags.
164 • debug = add the IMAGE_SCN_CNT_INITIALIZED_DATA, IM‐
166 AGE_SCN_MEM_DISCARDABLE and IMAGE_SCN_MEM_READ flags.
167 • code = add the IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE and
169 IMAGE_SCN_MEM_READ flags.
170 • data = add the IMAGE_SCN_CNT_INITIALIZED_DATA and IM‐
172 AGE_SCN_MEM_READ flags.
173 • share = add the IMAGE_SCN_MEM_SHARED and IMAGE_SCN_MEM_READ
175 flags.
176 --strip-all-gnu
178 Remove all symbols, debug sections and relocations from the out‐
179 put. This option is equivalent to GNU objcopy's --strip-all
180 switch.
181 --strip-all, -S
183 For ELF objects, remove from the output all symbols and non-al‐
184 loc sections not within segments, except for .gnu.warning,
185 .ARM.attribute sections and the section name table.
186 For COFF and Mach-O objects, remove all symbols, debug sections,
188 and relocations from the output.
189 --strip-debug, -g
191 Remove all debug sections from the output.
192 --strip-symbol <symbol>, -N
194 Remove all symbols named <symbol> from the output. Can be speci‐
195 fied multiple times to remove multiple symbols.
196 --strip-symbols <filename>
198 Remove all symbols whose names appear in the file <filename>,
199 from the output. In the file, each line represents a single sym‐
200 bol name, with leading and trailing whitespace ignored, as is
201 anything following a '#'. Can be specified multiple times to
202 read names from multiple files.
203 --strip-unneeded-symbol <symbol>
205 Remove from the output all symbols named <symbol> that are local
206 or undefined and are not required by any relocation.
207 --strip-unneeded-symbols <filename>
209 Remove all symbols whose names appear in the file <filename>,
210 from the output, if they are local or undefined and are not re‐
211 quired by any relocation. In the file, each line represents a
212 single symbol name, with leading and trailing whitespace ig‐
213 nored, as is anything following a '#'. Can be specified multiple
214 times to read names from multiple files.
215 --strip-unneeded
217 Remove from the output all local or undefined symbols that are
218 not required by relocations. Also remove all debug sections.
219 --version, -V
221 Display the version of the llvm-objcopy executable.
222 --wildcard, -w
224 Allow wildcard syntax for symbol-related flags. On by default
225 for section-related flags. Incompatible with --regex.
226 Wildcard syntax allows the following special symbols:
228 ┌───────────────┬─────────────────────┬────────────┐
230 │Character │ Meaning │ Equivalent │
231 ├───────────────┼─────────────────────┼────────────┤
232 │* │ Any number of char‐ │ .* │
233 │ │ acters │ │
234 ├───────────────┼─────────────────────┼────────────┤
235 │? │ Any single charac‐ │ . │
236 │ │ ter │ │
237 ├───────────────┼─────────────────────┼────────────┤
238 │\ │ Escape the next │ \ │
239 │ │ character │ │
240 ├───────────────┼─────────────────────┼────────────┤
241 │[a-z] │ Character class │ [a-z] │
242 ├───────────────┼─────────────────────┼────────────┤
243 │[!a-z], [^a-z] │ Negated character │ [^a-z] │
244 │ │ class │ │
245 └───────────────┴─────────────────────┴────────────┘
246 Additionally, starting a wildcard with '!' will prevent a match,
248 even if another flag matches. For example -w -N '*' -N '!x' will
249 strip all symbols except for x.
250 The order of wildcards does not matter. For example, -w -N '*'
252 -N '!x' is the same as -w -N '!x' -N '*'.
253 @<FILE>
255 Read command-line options and commands from response file
256 <FILE>.
257
259 The following options are implemented only for ELF objects. If used
260 with other objects, llvm-objcopy will either emit an error or silently
261 ignore them.
262 --add-symbol <name>=[<section>:]<value>[,<flags>]
264 Add a new symbol called <name> to the output symbol table, in
265 the section named <section>, with value <value>. If <section> is
266 not specified, the symbol is added as an absolute symbol. The
267 <flags> affect the symbol properties. Accepted values are:
268 • global = the symbol will have global binding.
270 • local = the symbol will have local binding.
272 • weak = the symbol will have weak binding.
274 • default = the symbol will have default visibility.
276 • hidden = the symbol will have hidden visibility.
278 • protected = the symbol will have protected visibility.
280 • file = the symbol will be an STT_FILE symbol.
282 • section = the symbol will be an STT_SECTION symbol.
284 • object = the symbol will be an STT_OBJECT symbol.
286 • function = the symbol will be an STT_FUNC symbol.
288 • indirect-function = the symbol will be an STT_GNU_IFUNC sym‐
290 bol.
291 Additionally, the following flags are accepted but ignored: de‐
293 bug, constructor, warning, indirect, synthetic, unique-object,
294 before.
295 Can be specified multiple times to add multiple symbols.
297 --allow-broken-links
299 Allow llvm-objcopy to remove sections even if it would leave in‐
300 valid section references. Any invalid sh_link fields will be set
301 to zero.
302 --build-id-link-dir <dir>
304 Set the directory used by --build-id-link-input and
305 --build-id-link-output.
306 --build-id-link-input <suffix>
308 Hard-link the input to <dir>/xx/xxx<suffix>, where <dir> is the
309 directory specified by --build-id-link-dir. The path used is de‐
310 rived from the hex build ID.
311 --build-id-link-output <suffix>
313 Hard-link the output to <dir>/xx/xxx<suffix>, where <dir> is the
314 directory specified by --build-id-link-dir. The path used is de‐
315 rived from the hex build ID.
316 --change-start <incr>, --adjust-start
318 Add <incr> to the program's start address. Can be specified mul‐
319 tiple times, in which case the values will be applied cumula‐
320 tively.
321 --compress-debug-sections [<style>]
323 Compress DWARF debug sections in the output, using the specified
324 style. Supported styles are zlib-gnu and zlib. Defaults to zlib
325 if no style is specified.
326 --decompress-debug-sections
328 Decompress any compressed DWARF debug sections in the output.
329 --discard-locals, -X
331 Remove local symbols starting with ".L" from the output.
332 --extract-dwo
334 Remove all sections that are not DWARF .dwo sections from the
335 output.
336 --extract-main-partition
338 Extract the main partition from the output.
339 --extract-partition <name>
341 Extract the named partition from the output.
342 --globalize-symbol <symbol>
344 Mark any defined symbols named <symbol> as global symbols in the
345 output. Can be specified multiple times to mark multiple sym‐
346 bols.
347 --globalize-symbols <filename>
349 Read a list of names from the file <filename> and mark defined
350 symbols with those names as global in the output. In the file,
351 each line represents a single symbol, with leading and trailing
352 whitespace ignored, as is anything following a '#'. Can be spec‐
353 ified multiple times to read names from multiple files.
354 --input-target <format>, -I
356 Read the input as the specified format. See SUPPORTED FORMATS
357 for a list of valid <format> values. If unspecified, llvm-obj‐
358 copy will attempt to determine the format automatically.
359 --keep-file-symbols
361 Keep symbols of type STT_FILE, even if they would otherwise be
362 stripped.
363 --keep-global-symbol <symbol>
365 Make all symbols local in the output, except for symbols with
366 the name <symbol>. Can be specified multiple times to ignore
367 multiple symbols.
368 --keep-global-symbols <filename>
370 Make all symbols local in the output, except for symbols named
371 in the file <filename>. In the file, each line represents a sin‐
372 gle symbol, with leading and trailing whitespace ignored, as is
373 anything following a '#'. Can be specified multiple times to
374 read names from multiple files.
375 --keep-section <section>
377 When removing sections from the output, do not remove sections
378 named <section>. Can be specified multiple times to keep multi‐
379 ple sections.
380 --keep-symbol <symbol>, -K
382 When removing symbols from the output, do not remove symbols
383 named <symbol>. Can be specified multiple times to keep multiple
384 symbols.
385 --keep-symbols <filename>
387 When removing symbols from the output do not remove symbols
388 named in the file <filename>. In the file, each line represents
389 a single symbol, with leading and trailing whitespace ignored,
390 as is anything following a '#'. Can be specified multiple times
391 to read names from multiple files.
392 --localize-hidden
394 Make all symbols with hidden or internal visibility local in the
395 output.
396 --localize-symbol <symbol>, -L
398 Mark any defined non-common symbol named <symbol> as a local
399 symbol in the output. Can be specified multiple times to mark
400 multiple symbols as local.
401 --localize-symbols <filename>
403 Read a list of names from the file <filename> and mark defined
404 non-common symbols with those names as local in the output. In
405 the file, each line represents a single symbol, with leading and
406 trailing whitespace ignored, as is anything following a '#'. Can
407 be specified multiple times to read names from multiple files.
408 --new-symbol-visibility <visibility>
410 Specify the visibility of the symbols automatically created when
411 using binary input or --add-symbol. Valid options are:
412 • default
414 • hidden
416 • internal
418 • protected
420 The default is default.
422 --output-target <format>, -O
424 Write the output as the specified format. See SUPPORTED FORMATS
425 for a list of valid <format> values. If unspecified, the output
426 format is assumed to be the same as the value specified for
427 --input-target or the input file's format if that option is also
428 unspecified.
429 --prefix-alloc-sections <prefix>
431 Add <prefix> to the front of the names of all allocatable sec‐
432 tions in the output.
433 --prefix-symbols <prefix>
435 Add <prefix> to the front of every symbol name in the output.
436 --preserve-dates, -p
438 Preserve access and modification timestamps in the output.
439 --rename-section <old>=<new>[,<flag>,...]
441 Rename sections called <old> to <new> in the output, and apply
442 any specified <flag> values. See --set-section-flags for a list
443 of supported flags. Can be specified multiple times to rename
444 multiple sections.
445 --set-start-addr <addr>
447 Set the start address of the output to <addr>. Overrides any
448 previously specified --change-start or --adjust-start options.
449 --split-dwo <dwo-file>
451 Equivalent to running llvm-objcopy with --extract-dwo and
452 <dwo-file> as the output file and no other options, and then
453 with --strip-dwo on the input file.
454 --strip-dwo
456 Remove all DWARF .dwo sections from the output.
457 --strip-non-alloc
459 Remove from the output all non-allocatable sections that are not
460 within segments.
461 --strip-sections
463 Remove from the output all section headers and all section data
464 not within segments. Note that many tools will not be able to
465 use an object without section headers.
466 --target <format>, -F
468 Equivalent to --input-target and --output-target for the speci‐
469 fied format. See SUPPORTED FORMATS for a list of valid <format>
470 values.
471 --weaken-symbol <symbol>, -W
473 Mark any global symbol named <symbol> as a weak symbol in the
474 output. Can be specified multiple times to mark multiple symbols
475 as weak.
476 --weaken-symbols <filename>
478 Read a list of names from the file <filename> and mark global
479 symbols with those names as weak in the output. In the file,
480 each line represents a single symbol, with leading and trailing
481 whitespace ignored, as is anything following a '#'. Can be spec‐
482 ified multiple times to read names from multiple files.
483 --weaken
485 Mark all defined global symbols as weak in the output.
486
488 The following values are currently supported by llvm-objcopy for the
489 --input-target, --output-target, and --target options. For GNU objcopy
490 compatibility, the values are all bfdnames.
491 • binary
493 • ihex
495 • elf32-i386
497 • elf32-x86-64
499 • elf64-x86-64
501 • elf32-iamcu
503 • elf32-littlearm
505 • elf64-aarch64
507 • elf64-littleaarch64
509 • elf32-littleriscv
511 • elf64-littleriscv
513 • elf32-powerpc
515 • elf32-powerpcle
517 • elf64-powerpc
519 • elf64-powerpcle
521 • elf32-bigmips
523 • elf32-ntradbigmips
525 • elf32-ntradlittlemips
527 • elf32-tradbigmips
529 • elf32-tradlittlemips
531 • elf64-tradbigmips
533 • elf64-tradlittlemips
535 • elf32-sparc
537 • elf32-sparcel
539 Additionally, all targets except binary and ihex can have -freebsd as a
541 suffix.
542
544 If binary is used as the value for --input-target, the input file will
545 be embedded as a data section in an ELF relocatable object, with sym‐
546 bols _binary_<file_name>_start, _binary_<file_name>_end, and _bi‐
547 nary_<file_name>_size representing the start, end and size of the data,
548 where <file_name> is the path of the input file as specified on the
549 command line with non-alphanumeric characters converted to _.
550 If binary is used as the value for --output-target, the output file
552 will be a raw binary file, containing the memory image of the input
553 file. Symbols and relocation information will be discarded. The image
554 will start at the address of the first loadable section in the output.
555
557 llvm-objcopy exits with a non-zero exit code if there is an error.
558 Otherwise, it exits with code 0.
559
561 To report bugs, please visit <https://bugs.llvm.org/>.
562 There is a known issue with --input-target and --target causing only
564 binary and ihex formats to have any effect. Other values will be ig‐
565 nored and llvm-objcopy will attempt to guess the input format.
566
568 llvm-strip(1)
569
571 Maintained by the LLVM Team (https://llvm.org/).
572
574 2003-2021, LLVM Project
57511 2021-07-22 LLVM-OBJCOPY(1)