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 --strip-all-gnu
122 Remove all symbols, debug sections and relocations from the out‐
123 put. This option is equivalent to GNU objcopy's --strip-all
124 switch.
125 --strip-all, -S
127 For ELF objects, remove from the output all symbols and non-al‐
128 loc sections not within segments, except for .gnu.warning,
129 .ARM.attribute sections and the section name table.
130 For COFF and Mach-O objects, remove all symbols, debug sections,
132 and relocations from the output.
133 --strip-debug, -g
135 Remove all debug sections from the output.
136 --strip-symbol <symbol>, -N
138 Remove all symbols named <symbol> from the output. Can be speci‐
139 fied multiple times to remove multiple symbols.
140 --strip-symbols <filename>
142 Remove all symbols whose names appear in the file <filename>,
143 from the output. In the file, each line represents a single sym‐
144 bol name, with leading and trailing whitespace ignored, as is
145 anything following a '#'. Can be specified multiple times to
146 read names from multiple files.
147 --strip-unneeded-symbol <symbol>
149 Remove from the output all symbols named <symbol> that are local
150 or undefined and are not required by any relocation.
151 --strip-unneeded-symbols <filename>
153 Remove all symbols whose names appear in the file <filename>,
154 from the output, if they are local or undefined and are not re‐
155 quired by any relocation. In the file, each line represents a
156 single symbol name, with leading and trailing whitespace ig‐
157 nored, as is anything following a '#'. Can be specified multiple
158 times to read names from multiple files.
159 --strip-unneeded
161 Remove from the output all local or undefined symbols that are
162 not required by relocations. Also remove all debug sections.
163 --version, -V
165 Display the version of the llvm-objcopy executable.
166 @<FILE>
168 Read command-line options and commands from response file
169 <FILE>.
170 --wildcard, -w
172 Allow wildcard syntax for symbol-related flags. On by default
173 for section-related flags. Incompatible with --regex.
174 Wildcard syntax allows the following special symbols:
176 ┌───────────────┬─────────────────────┬────────────┐
178 │Character │ Meaning │ Equivalent │
179 ├───────────────┼─────────────────────┼────────────┤
180 │* │ Any number of char‐ │ .* │
181 │ │ acters │ │
182 ├───────────────┼─────────────────────┼────────────┤
183 │? │ Any single charac‐ │ . │
184 │ │ ter │ │
185 ├───────────────┼─────────────────────┼────────────┤
186 │\ │ Escape the next │ \ │
187 │ │ character │ │
188 ├───────────────┼─────────────────────┼────────────┤
189 │[a-z] │ Character class │ [a-z] │
190 ├───────────────┼─────────────────────┼────────────┤
191 │[!a-z], [^a-z] │ Negated character │ [^a-z] │
192 │ │ class │ │
193 └───────────────┴─────────────────────┴────────────┘
194 Additionally, starting a wildcard with '!' will prevent a match,
196 even if another flag matches. For example -w -N '*' -N '!x' will
197 strip all symbols except for x.
198 The order of wildcards does not matter. For example, -w -N '*'
200 -N '!x' is the same as -w -N '!x' -N '*'.
201
203 The following options are implemented only for COFF objects. If used
204 with other objects, llvm-objcopy will either emit an error or silently
205 ignore them.
206
208 The following options are implemented only for ELF objects. If used
209 with other objects, llvm-objcopy will either emit an error or silently
210 ignore them.
211 --add-symbol <name>=[<section>:]<value>[,<flags>]
213 Add a new symbol called <name> to the output symbol table, in
214 the section named <section>, with value <value>. If <section> is
215 not specified, the symbol is added as an absolute symbol. The
216 <flags> affect the symbol properties. Accepted values are:
217 • global = the symbol will have global binding.
219 • local = the symbol will have local binding.
221 • weak = the symbol will have weak binding.
223 • default = the symbol will have default visibility.
225 • hidden = the symbol will have hidden visibility.
227 • protected = the symbol will have protected visibility.
229 • file = the symbol will be an STT_FILE symbol.
231 • section = the symbol will be an STT_SECTION symbol.
233 • object = the symbol will be an STT_OBJECT symbol.
235 • function = the symbol will be an STT_FUNC symbol.
237 • indirect-function = the symbol will be an STT_GNU_IFUNC sym‐
239 bol.
240 Additionally, the following flags are accepted but ignored: de‐
242 bug, constructor, warning, indirect, synthetic, unique-object,
243 before.
244 Can be specified multiple times to add multiple symbols.
246 --allow-broken-links
248 Allow llvm-objcopy to remove sections even if it would leave in‐
249 valid section references. Any invalid sh_link fields will be set
250 to zero.
251 --build-id-link-dir <dir>
253 Set the directory used by --build-id-link-input and
254 --build-id-link-output.
255 --build-id-link-input <suffix>
257 Hard-link the input to <dir>/xx/xxx<suffix>, where <dir> is the
258 directory specified by --build-id-link-dir. The path used is de‐
259 rived from the hex build ID.
260 --build-id-link-output <suffix>
262 Hard-link the output to <dir>/xx/xxx<suffix>, where <dir> is the
263 directory specified by --build-id-link-dir. The path used is de‐
264 rived from the hex build ID.
265 --change-start <incr>, --adjust-start
267 Add <incr> to the program's start address. Can be specified mul‐
268 tiple times, in which case the values will be applied cumula‐
269 tively.
270 --compress-debug-sections [<style>]
272 Compress DWARF debug sections in the output, using the specified
273 style. Supported styles are zlib-gnu and zlib. Defaults to zlib
274 if no style is specified.
275 --decompress-debug-sections
277 Decompress any compressed DWARF debug sections in the output.
278 --discard-locals, -X
280 Remove local symbols starting with ".L" from the output.
281 --extract-dwo
283 Remove all sections that are not DWARF .dwo sections from the
284 output.
285 --extract-main-partition
287 Extract the main partition from the output.
288 --extract-partition <name>
290 Extract the named partition from the output.
291 --globalize-symbol <symbol>
293 Mark any defined symbols named <symbol> as global symbols in the
294 output. Can be specified multiple times to mark multiple sym‐
295 bols.
296 --globalize-symbols <filename>
298 Read a list of names from the file <filename> and mark defined
299 symbols with those names as global in the output. In the file,
300 each line represents a single symbol, with leading and trailing
301 whitespace ignored, as is anything following a '#'. Can be spec‐
302 ified multiple times to read names from multiple files.
303 --input-target <format>, -I
305 Read the input as the specified format. See SUPPORTED FORMATS
306 for a list of valid <format> values. If unspecified, llvm-obj‐
307 copy will attempt to determine the format automatically.
308 --keep-file-symbols
310 Keep symbols of type STT_FILE, even if they would otherwise be
311 stripped.
312 --keep-global-symbol <symbol>
314 Make all symbols local in the output, except for symbols with
315 the name <symbol>. Can be specified multiple times to ignore
316 multiple symbols.
317 --keep-global-symbols <filename>
319 Make all symbols local in the output, except for symbols named
320 in the file <filename>. In the file, each line represents a sin‐
321 gle symbol, with leading and trailing whitespace ignored, as is
322 anything following a '#'. Can be specified multiple times to
323 read names from multiple files.
324 --keep-section <section>
326 When removing sections from the output, do not remove sections
327 named <section>. Can be specified multiple times to keep multi‐
328 ple sections.
329 --keep-symbol <symbol>, -K
331 When removing symbols from the output, do not remove symbols
332 named <symbol>. Can be specified multiple times to keep multiple
333 symbols.
334 --keep-symbols <filename>
336 When removing symbols from the output do not remove symbols
337 named in the file <filename>. In the file, each line represents
338 a single symbol, with leading and trailing whitespace ignored,
339 as is anything following a '#'. Can be specified multiple times
340 to read names from multiple files.
341 --localize-hidden
343 Make all symbols with hidden or internal visibility local in the
344 output.
345 --localize-symbol <symbol>, -L
347 Mark any defined non-common symbol named <symbol> as a local
348 symbol in the output. Can be specified multiple times to mark
349 multiple symbols as local.
350 --localize-symbols <filename>
352 Read a list of names from the file <filename> and mark defined
353 non-common symbols with those names as local in the output. In
354 the file, each line represents a single symbol, with leading and
355 trailing whitespace ignored, as is anything following a '#'. Can
356 be specified multiple times to read names from multiple files.
357 --new-symbol-visibility <visibility>
359 Specify the visibility of the symbols automatically created when
360 using binary input or --add-symbol. Valid options are:
361 • default
363 • hidden
365 • internal
367 • protected
369 The default is default.
371 --output-target <format>, -O
373 Write the output as the specified format. See SUPPORTED FORMATS
374 for a list of valid <format> values. If unspecified, the output
375 format is assumed to be the same as the input file's format.
376 --prefix-alloc-sections <prefix>
378 Add <prefix> to the front of the names of all allocatable sec‐
379 tions in the output.
380 --prefix-symbols <prefix>
382 Add <prefix> to the front of every symbol name in the output.
383 --preserve-dates, -p
385 Preserve access and modification timestamps in the output.
386 --rename-section <old>=<new>[,<flag>,...]
388 Rename sections called <old> to <new> in the output, and apply
389 any specified <flag> values. See --set-section-flags for a list
390 of supported flags. Can be specified multiple times to rename
391 multiple sections.
392 --set-section-flags <section>=<flag>[,<flag>,...]
394 Set section properties in the output of section <section> based
395 on the specified <flag> values. Can be specified multiple times
396 to update multiple sections.
397 Following is a list of supported flags and their effects:
399 • alloc = add the SHF_ALLOC flag.
401 • load = if the section has SHT_NOBITS type, mark it as a
403 SHT_PROGBITS section.
404 • readonly = if this flag is not specified, add the SHF_WRITE
406 flag.
407 • code = add the SHF_EXECINSTR flag.
409 • merge = add the SHF_MERGE flag.
411 • strings = add the SHF_STRINGS flag.
413 • contents = if the section has SHT_NOBITS type, mark it as a
415 SHT_PROGBITS section.
416 The following flags are also accepted, but are ignored for GNU
418 compatibility: noload, debug, data, rom, share.
419 --set-start-addr <addr>
421 Set the start address of the output to <addr>. Overrides any
422 previously specified --change-start or --adjust-start options.
423 --split-dwo <dwo-file>
425 Equivalent to running llvm-objcopy with --extract-dwo and
426 <dwo-file> as the output file and no other options, and then
427 with --strip-dwo on the input file.
428 --strip-dwo
430 Remove all DWARF .dwo sections from the output.
431 --strip-non-alloc
433 Remove from the output all non-allocatable sections that are not
434 within segments.
435 --strip-sections
437 Remove from the output all section headers and all section data
438 not within segments. Note that many tools will not be able to
439 use an object without section headers.
440 --target <format>, -F
442 Equivalent to --input-target and --output-target for the speci‐
443 fied format. See SUPPORTED FORMATS for a list of valid <format>
444 values.
445 --weaken-symbol <symbol>, -W
447 Mark any global symbol named <symbol> as a weak symbol in the
448 output. Can be specified multiple times to mark multiple symbols
449 as weak.
450 --weaken-symbols <filename>
452 Read a list of names from the file <filename> and mark global
453 symbols with those names as weak in the output. In the file,
454 each line represents a single symbol, with leading and trailing
455 whitespace ignored, as is anything following a '#'. Can be spec‐
456 ified multiple times to read names from multiple files.
457 --weaken
459 Mark all defined global symbols as weak in the output.
460
462 The following values are currently supported by llvm-objcopy for the
463 --input-target, --output-target, and --target options. For GNU objcopy
464 compatibility, the values are all bfdnames.
465 • binary
467 • ihex
469 • elf32-i386
471 • elf32-x86-64
473 • elf64-x86-64
475 • elf32-iamcu
477 • elf32-littlearm
479 • elf64-aarch64
481 • elf64-littleaarch64
483 • elf32-littleriscv
485 • elf64-littleriscv
487 • elf32-powerpc
489 • elf32-powerpcle
491 • elf64-powerpc
493 • elf64-powerpcle
495 • elf32-bigmips
497 • elf32-ntradbigmips
499 • elf32-ntradlittlemips
501 • elf32-tradbigmips
503 • elf32-tradlittlemips
505 • elf64-tradbigmips
507 • elf64-tradlittlemips
509 • elf32-sparc
511 • elf32-sparcel
513 Additionally, all targets except binary and ihex can have -freebsd as a
515 suffix.
516
518 If binary is used as the value for --input-target, the input file will
519 be embedded as a data section in an ELF relocatable object, with sym‐
520 bols _binary_<file_name>_start, _binary_<file_name>_end, and _bi‐
521 nary_<file_name>_size representing the start, end and size of the data,
522 where <file_name> is the path of the input file as specified on the
523 command line with non-alphanumeric characters converted to _.
524 If binary is used as the value for --output-target, the output file
526 will be a raw binary file, containing the memory image of the input
527 file. Symbols and relocation information will be discarded. The image
528 will start at the address of the first loadable section in the output.
529
531 llvm-objcopy exits with a non-zero exit code if there is an error.
532 Otherwise, it exits with code 0.
533
535 To report bugs, please visit <http://llvm.org/bugs/>.
536 There is a known issue with --input-target and --target causing only
538 binary and ihex formats to have any effect. Other values will be ig‐
539 nored and llvm-objcopy will attempt to guess the input format.
540
542 llvm-strip(1)
543
545 Maintained by the LLVM Team (https://llvm.org/).
546
548 2003-2021, LLVM Project
54910 2021-07-22 LLVM-OBJCOPY(1)