1OBJCOPY(1) GNU Development Tools OBJCOPY(1)
2
6 objcopy - copy and translate object files
7
9 objcopy [-F bfdname⎪--target=bfdname]
10 [-I bfdname⎪--input-target=bfdname]
11 [-O bfdname⎪--output-target=bfdname]
12 [-B bfdarch⎪--binary-architecture=bfdarch]
13 [-S⎪--strip-all]
14 [-g⎪--strip-debug]
15 [-K symbolname⎪--keep-symbol=symbolname]
16 [-N symbolname⎪--strip-symbol=symbolname]
17 [--strip-unneeded-symbol=symbolname]
18 [-G symbolname⎪--keep-global-symbol=symbolname]
19 [--localize-hidden]
20 [-L symbolname⎪--localize-symbol=symbolname]
21 [--globalize-symbol=symbolname]
22 [-W symbolname⎪--weaken-symbol=symbolname]
23 [-w⎪--wildcard]
24 [-x⎪--discard-all]
25 [-X⎪--discard-locals]
26 [-b byte⎪--byte=byte]
27 [-i interleave⎪--interleave=interleave]
28 [-j sectionname⎪--only-section=sectionname]
29 [-R sectionname⎪--remove-section=sectionname]
30 [-p⎪--preserve-dates]
31 [--debugging]
32 [--gap-fill=val]
33 [--pad-to=address]
34 [--set-start=val]
35 [--adjust-start=incr]
36 [--change-addresses=incr]
37 [--change-section-address section{=,+,-}val]
38 [--change-section-lma section{=,+,-}val]
39 [--change-section-vma section{=,+,-}val]
40 [--change-warnings] [--no-change-warnings]
41 [--set-section-flags section=flags]
42 [--add-section sectionname=filename]
43 [--rename-section oldname=newname[,flags]]
44 [--change-leading-char] [--remove-leading-char]
45 [--reverse-bytes=num]
46 [--srec-len=ival] [--srec-forceS3]
47 [--redefine-sym old=new]
48 [--redefine-syms=filename]
49 [--weaken]
50 [--keep-symbols=filename]
51 [--strip-symbols=filename]
52 [--strip-unneeded-symbols=filename]
53 [--keep-global-symbols=filename]
54 [--localize-symbols=filename]
55 [--globalize-symbols=filename]
56 [--weaken-symbols=filename]
57 [--alt-machine-code=index]
58 [--prefix-symbols=string]
59 [--prefix-sections=string]
60 [--prefix-alloc-sections=string]
61 [--add-gnu-debuglink=path-to-file]
62 [--keep-file-symbols]
63 [--only-keep-debug]
64 [--extract-symbol]
65 [--writable-text]
66 [--readonly-text]
67 [--pure]
68 [--impure]
69 [-v⎪--verbose]
70 [-V⎪--version]
71 [--help] [--info]
72 infile [outfile]
73
75 The GNU objcopy utility copies the contents of an object file to
76 another. objcopy uses the GNU BFD Library to read and write the object
77 files. It can write the destination object file in a format different
78 from that of the source object file. The exact behavior of objcopy is
79 controlled by command-line options. Note that objcopy should be able
80 to copy a fully linked file between any two formats. However, copying a
81 relocatable object file between any two formats may not work as
82 expected.
83 objcopy creates temporary files to do its translations and deletes them
85 afterward. objcopy uses BFD to do all its translation work; it has
86 access to all the formats described in BFD and thus is able to recog‐
87 nize most formats without being told explicitly.
88 objcopy can be used to generate S-records by using an output target of
90 srec (e.g., use -O srec).
91 objcopy can be used to generate a raw binary file by using an output
93 target of binary (e.g., use -O binary). When objcopy generates a raw
94 binary file, it will essentially produce a memory dump of the contents
95 of the input object file. All symbols and relocation information will
96 be discarded. The memory dump will start at the load address of the
97 lowest section copied into the output file.
98 When generating an S-record or a raw binary file, it may be helpful to
100 use -S to remove sections containing debugging information. In some
101 cases -R will be useful to remove sections which contain information
102 that is not needed by the binary file.
103 Note---objcopy is not able to change the endianness of its input files.
105 If the input format has an endianness (some formats do not), objcopy
106 can only copy the inputs into file formats that have the same endian‐
107 ness or which have no endianness (e.g., srec). (However, see the
108 --reverse-bytes option.)
109
111 infile
112 outfile
113 The input and output files, respectively. If you do not specify
114 outfile, objcopy creates a temporary file and destructively renames
115 the result with the name of infile.
116 -I bfdname
118 --input-target=bfdname
119 Consider the source file's object format to be bfdname, rather than
120 attempting to deduce it.
121 -O bfdname
123 --output-target=bfdname
124 Write the output file using the object format bfdname.
125 -F bfdname
127 --target=bfdname
128 Use bfdname as the object format for both the input and the output
129 file; i.e., simply transfer data from source to destination with no
130 translation.
131 -B bfdarch
133 --binary-architecture=bfdarch
134 Useful when transforming a raw binary input file into an object
135 file. In this case the output architecture can be set to bfdarch.
136 This option will be ignored if the input file has a known bfdarch.
137 You can access this binary data inside a program by referencing the
138 special symbols that are created by the conversion process. These
139 symbols are called _binary_objfile_start, _binary_objfile_end and
140 _binary_objfile_size. e.g. you can transform a picture file into
141 an object file and then access it in your code using these symbols.
142 -j sectionname
144 --only-section=sectionname
145 Copy only the named section from the input file to the output file.
146 This option may be given more than once. Note that using this
147 option inappropriately may make the output file unusable.
148 -R sectionname
150 --remove-section=sectionname
151 Remove any section named sectionname from the output file. This
152 option may be given more than once. Note that using this option
153 inappropriately may make the output file unusable.
154 -S
156 --strip-all
157 Do not copy relocation and symbol information from the source file.
158 -g
160 --strip-debug
161 Do not copy debugging symbols or sections from the source file.
162 --strip-unneeded
164 Strip all symbols that are not needed for relocation processing.
165 -K symbolname
167 --keep-symbol=symbolname
168 When stripping symbols, keep symbol symbolname even if it would
169 normally be stripped. This option may be given more than once.
170 -N symbolname
172 --strip-symbol=symbolname
173 Do not copy symbol symbolname from the source file. This option
174 may be given more than once.
175 --strip-unneeded-symbol=symbolname
177 Do not copy symbol symbolname from the source file unless it is
178 needed by a relocation. This option may be given more than once.
179 -G symbolname
181 --keep-global-symbol=symbolname
182 Keep only symbol symbolname global. Make all other symbols local
183 to the file, so that they are not visible externally. This option
184 may be given more than once.
185 --localize-hidden
187 In an ELF object, mark all symbols that have hidden or internal
188 visibility as local. This option applies on top of symbol-specific
189 localization options such as -L.
190 -L symbolname
192 --localize-symbol=symbolname
193 Make symbol symbolname local to the file, so that it is not visible
194 externally. This option may be given more than once.
195 -W symbolname
197 --weaken-symbol=symbolname
198 Make symbol symbolname weak. This option may be given more than
199 once.
200 --globalize-symbol=symbolname
202 Give symbol symbolname global scoping so that it is visible outside
203 of the file in which it is defined. This option may be given more
204 than once.
205 -w
207 --wildcard
208 Permit regular expressions in symbolnames used in other command
209 line options. The question mark (?), asterisk (*), backslash (\)
210 and square brackets ([]) operators can be used anywhere in the sym‐
211 bol name. If the first character of the symbol name is the excla‐
212 mation point (!) then the sense of the switch is reversed for that
213 symbol. For example:
214 -w -W !foo -W fo*
216 would cause objcopy to weaken all symbols that start with "fo"
218 except for the symbol "foo".
219 -x
221 --discard-all
222 Do not copy non-global symbols from the source file.
223 -X
225 --discard-locals
226 Do not copy compiler-generated local symbols. (These usually start
227 with L or ..)
228 -b byte
230 --byte=byte
231 Keep only every byteth byte of the input file (header data is not
232 affected). byte can be in the range from 0 to interleave-1, where
233 interleave is given by the -i or --interleave option, or the
234 default of 4. This option is useful for creating files to program
235 ROM. It is typically used with an "srec" output target.
236 -i interleave
238 --interleave=interleave
239 Only copy one out of every interleave bytes. Select which byte to
240 copy with the -b or --byte option. The default is 4. objcopy
241 ignores this option if you do not specify either -b or --byte.
242 -p
244 --preserve-dates
245 Set the access and modification dates of the output file to be the
246 same as those of the input file.
247 --debugging
249 Convert debugging information, if possible. This is not the
250 default because only certain debugging formats are supported, and
251 the conversion process can be time consuming.
252 --gap-fill val
254 Fill gaps between sections with val. This operation applies to the
255 load address (LMA) of the sections. It is done by increasing the
256 size of the section with the lower address, and filling in the
257 extra space created with val.
258 --pad-to address
260 Pad the output file up to the load address address. This is done
261 by increasing the size of the last section. The extra space is
262 filled in with the value specified by --gap-fill (default zero).
263 --set-start val
265 Set the start address of the new file to val. Not all object file
266 formats support setting the start address.
267 --change-start incr
269 --adjust-start incr
270 Change the start address by adding incr. Not all object file for‐
271 mats support setting the start address.
272 --change-addresses incr
274 --adjust-vma incr
275 Change the VMA and LMA addresses of all sections, as well as the
276 start address, by adding incr. Some object file formats do not
277 permit section addresses to be changed arbitrarily. Note that this
278 does not relocate the sections; if the program expects sections to
279 be loaded at a certain address, and this option is used to change
280 the sections such that they are loaded at a different address, the
281 program may fail.
282 --change-section-address section{=,+,-}val
284 --adjust-section-vma section{=,+,-}val
285 Set or change both the VMA address and the LMA address of the named
286 section. If = is used, the section address is set to val. Other‐
287 wise, val is added to or subtracted from the section address. See
288 the comments under --change-addresses, above. If section does not
289 exist in the input file, a warning will be issued, unless
290 --no-change-warnings is used.
291 --change-section-lma section{=,+,-}val
293 Set or change the LMA address of the named section. The LMA
294 address is the address where the section will be loaded into memory
295 at program load time. Normally this is the same as the VMA
296 address, which is the address of the section at program run time,
297 but on some systems, especially those where a program is held in
298 ROM, the two can be different. If = is used, the section address
299 is set to val. Otherwise, val is added to or subtracted from the
300 section address. See the comments under --change-addresses, above.
301 If section does not exist in the input file, a warning will be
302 issued, unless --no-change-warnings is used.
303 --change-section-vma section{=,+,-}val
305 Set or change the VMA address of the named section. The VMA
306 address is the address where the section will be located once the
307 program has started executing. Normally this is the same as the
308 LMA address, which is the address where the section will be loaded
309 into memory, but on some systems, especially those where a program
310 is held in ROM, the two can be different. If = is used, the sec‐
311 tion address is set to val. Otherwise, val is added to or sub‐
312 tracted from the section address. See the comments under
313 --change-addresses, above. If section does not exist in the input
314 file, a warning will be issued, unless --no-change-warnings is
315 used.
316 --change-warnings
318 --adjust-warnings
319 If --change-section-address or --change-section-lma or
320 --change-section-vma is used, and the named section does not exist,
321 issue a warning. This is the default.
322 --no-change-warnings
324 --no-adjust-warnings
325 Do not issue a warning if --change-section-address or --adjust-sec‐
326 tion-lma or --adjust-section-vma is used, even if the named section
327 does not exist.
328 --set-section-flags section=flags
330 Set the flags for the named section. The flags argument is a comma
331 separated string of flag names. The recognized names are alloc,
332 contents, load, noload, readonly, code, data, rom, share, and
333 debug. You can set the contents flag for a section which does not
334 have contents, but it is not meaningful to clear the contents flag
335 of a section which does have contents--just remove the section
336 instead. Not all flags are meaningful for all object file formats.
337 --add-section sectionname=filename
339 Add a new section named sectionname while copying the file. The
340 contents of the new section are taken from the file filename. The
341 size of the section will be the size of the file. This option only
342 works on file formats which can support sections with arbitrary
343 names.
344 --rename-section oldname=newname[,flags]
346 Rename a section from oldname to newname, optionally changing the
347 section's flags to flags in the process. This has the advantage
348 over usng a linker script to perform the rename in that the output
349 stays as an object file and does not become a linked executable.
350 This option is particularly helpful when the input format is
352 binary, since this will always create a section called .data. If
353 for example, you wanted instead to create a section called .rodata
354 containing binary data you could use the following command line to
355 achieve it:
356 objcopy -I binary -O <output_format> -B <architecture> \
358 --rename-section .data=.rodata,alloc,load,readonly,data,contents \
359 <input_binary_file> <output_object_file>
360 --change-leading-char
362 Some object file formats use special characters at the start of
363 symbols. The most common such character is underscore, which com‐
364 pilers often add before every symbol. This option tells objcopy to
365 change the leading character of every symbol when it converts
366 between object file formats. If the object file formats use the
367 same leading character, this option has no effect. Otherwise, it
368 will add a character, or remove a character, or change a character,
369 as appropriate.
370 --remove-leading-char
372 If the first character of a global symbol is a special symbol lead‐
373 ing character used by the object file format, remove the character.
374 The most common symbol leading character is underscore. This
375 option will remove a leading underscore from all global symbols.
376 This can be useful if you want to link together objects of differ‐
377 ent file formats with different conventions for symbol names. This
378 is different from --change-leading-char because it always changes
379 the symbol name when appropriate, regardless of the object file
380 format of the output file.
381 --reverse-bytes=num
383 Reverse the bytes in a section with output contents. A section
384 length must be evenly divisible by the value given in order for the
385 swap to be able to take place. Reversing takes place before the
386 interleaving is performed.
387 This option is used typically in generating ROM images for problem‐
389 atic target systems. For example, on some target boards, the
390 32-bit words fetched from 8-bit ROMs are re-assembled in little-
391 endian byte order regardless of the CPU byte order. Depending on
392 the programming model, the endianness of the ROM may need to be
393 modified.
394 Consider a simple file with a section containing the following
396 eight bytes: 12345678.
397 Using --reverse-bytes=2 for the above example, the bytes in the
399 output file would be ordered 21436587.
400 Using --reverse-bytes=4 for the above example, the bytes in the
402 output file would be ordered 43218765.
403 By using --reverse-bytes=2 for the above example, followed by
405 --reverse-bytes=4 on the output file, the bytes in the second out‐
406 put file would be ordered 34127856.
407 --srec-len=ival
409 Meaningful only for srec output. Set the maximum length of the
410 Srecords being produced to ival. This length covers both address,
411 data and crc fields.
412 --srec-forceS3
414 Meaningful only for srec output. Avoid generation of S1/S2
415 records, creating S3-only record format.
416 --redefine-sym old=new
418 Change the name of a symbol old, to new. This can be useful when
419 one is trying link two things together for which you have no
420 source, and there are name collisions.
421 --redefine-syms=filename
423 Apply --redefine-sym to each symbol pair "old new" listed in the
424 file filename. filename is simply a flat file, with one symbol
425 pair per line. Line comments may be introduced by the hash charac‐
426 ter. This option may be given more than once.
427 --weaken
429 Change all global symbols in the file to be weak. This can be use‐
430 ful when building an object which will be linked against other
431 objects using the -R option to the linker. This option is only
432 effective when using an object file format which supports weak sym‐
433 bols.
434 --keep-symbols=filename
436 Apply --keep-symbol option to each symbol listed in the file file‐
437 name. filename is simply a flat file, with one symbol name per
438 line. Line comments may be introduced by the hash character. This
439 option may be given more than once.
440 --strip-symbols=filename
442 Apply --strip-symbol option to each symbol listed in the file file‐
443 name. filename is simply a flat file, with one symbol name per
444 line. Line comments may be introduced by the hash character. This
445 option may be given more than once.
446 --strip-unneeded-symbols=filename
448 Apply --strip-unneeded-symbol option to each symbol listed in the
449 file filename. filename is simply a flat file, with one symbol
450 name per line. Line comments may be introduced by the hash charac‐
451 ter. This option may be given more than once.
452 --keep-global-symbols=filename
454 Apply --keep-global-symbol option to each symbol listed in the file
455 filename. filename is simply a flat file, with one symbol name per
456 line. Line comments may be introduced by the hash character. This
457 option may be given more than once.
458 --localize-symbols=filename
460 Apply --localize-symbol option to each symbol listed in the file
461 filename. filename is simply a flat file, with one symbol name per
462 line. Line comments may be introduced by the hash character. This
463 option may be given more than once.
464 --globalize-symbols=filename
466 Apply --globalize-symbol option to each symbol listed in the file
467 filename. filename is simply a flat file, with one symbol name per
468 line. Line comments may be introduced by the hash character. This
469 option may be given more than once.
470 --weaken-symbols=filename
472 Apply --weaken-symbol option to each symbol listed in the file
473 filename. filename is simply a flat file, with one symbol name per
474 line. Line comments may be introduced by the hash character. This
475 option may be given more than once.
476 --alt-machine-code=index
478 If the output architecture has alternate machine codes, use the
479 indexth code instead of the default one. This is useful in case a
480 machine is assigned an official code and the tool-chain adopts the
481 new code, but other applications still depend on the original code
482 being used. For ELF based architectures if the index alternative
483 does not exist then the value is treated as an absolute number to
484 be stored in the e_machine field of the ELF header.
485 --writable-text
487 Mark the output text as writable. This option isn't meaningful for
488 all object file formats.
489 --readonly-text
491 Make the output text write protected. This option isn't meaningful
492 for all object file formats.
493 --pure
495 Mark the output file as demand paged. This option isn't meaningful
496 for all object file formats.
497 --impure
499 Mark the output file as impure. This option isn't meaningful for
500 all object file formats.
501 --prefix-symbols=string
503 Prefix all symbols in the output file with string.
504 --prefix-sections=string
506 Prefix all section names in the output file with string.
507 --prefix-alloc-sections=string
509 Prefix all the names of all allocated sections in the output file
510 with string.
511 --add-gnu-debuglink=path-to-file
513 Creates a .gnu_debuglink section which contains a reference to
514 path-to-file and adds it to the output file.
515 --keep-file-symbols
517 When stripping a file, perhaps with --strip-debug or
518 --strip-unneeded, retain any symbols specifying source file names,
519 which would otherwise get stripped.
520 --only-keep-debug
522 Strip a file, removing contents of any sections that would not be
523 stripped by --strip-debug and leaving the debugging sections
524 intact. In ELF files, this preserves all note sections in the out‐
525 put.
526 The intention is that this option will be used in conjunction with
528 --add-gnu-debuglink to create a two part executable. One a
529 stripped binary which will occupy less space in RAM and in a dis‐
530 tribution and the second a debugging information file which is only
531 needed if debugging abilities are required. The suggested proce‐
532 dure to create these files is as follows:
533 1.<Link the executable as normal. Assuming that is is called>
535 "foo" then...
536 1.<Run "objcopy --only-keep-debug foo foo.dbg" to>
538 create a file containing the debugging info.
539 1.<Run "objcopy --strip-debug foo" to create a>
541 stripped executable.
542 1.<Run "objcopy --add-gnu-debuglink=foo.dbg foo">
544 to add a link to the debugging info into the stripped exe‐
545 cutable.
546 Note---the choice of ".dbg" as an extension for the debug info file
548 is arbitrary. Also the "--only-keep-debug" step is optional. You
549 could instead do this:
550 1.<Link the executable as normal.>
552 1.<Copy "foo" to "foo.full">
553 1.<Run "objcopy --strip-debug foo">
554 1.<Run "objcopy --add-gnu-debuglink=foo.full foo">
555 i.e., the file pointed to by the --add-gnu-debuglink can be the
557 full executable. It does not have to be a file created by the
558 --only-keep-debug switch.
559 Note---this switch is only intended for use on fully linked files.
561 It does not make sense to use it on object files where the debug‐
562 ging information may be incomplete. Besides the gnu_debuglink fea‐
563 ture currently only supports the presence of one filename contain‐
564 ing debugging information, not multiple filenames on a one-per-
565 object-file basis.
566 --extract-symbol
568 Keep the file's section flags and symbols but remove all section
569 data. Specifically, the option:
570 *<removes the contents of all sections;>
572 *<sets the size of every section to zero; and>
573 *<sets the file's start address to zero.>
574 This option is used to build a .sym file for a VxWorks kernel. It
576 can also be a useful way of reducing the size of a --just-symbols
577 linker input file.
578 -V
580 --version
581 Show the version number of objcopy.
582 -v
584 --verbose
585 Verbose output: list all object files modified. In the case of ar‐
586 chives, objcopy -V lists all members of the archive.
587 --help
589 Show a summary of the options to objcopy.
590 --info
592 Display a list showing all architectures and object formats avail‐
593 able.
594 @file
596 Read command-line options from file. The options read are inserted
597 in place of the original @file option. If file does not exist, or
598 cannot be read, then the option will be treated literally, and not
599 removed.
600 Options in file are separated by whitespace. A whitespace charac‐
602 ter may be included in an option by surrounding the entire option
603 in either single or double quotes. Any character (including a
604 backslash) may be included by prefixing the character to be
605 included with a backslash. The file may itself contain additional
606 @file options; any such options will be processed recursively.
607
609 ld(1), objdump(1), and the Info entries for binutils.
610
612 Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
613 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software
614 Foundation, Inc.
615 Permission is granted to copy, distribute and/or modify this document
617 under the terms of the GNU Free Documentation License, Version 1.2 or
618 any later version published by the Free Software Foundation; with no
619 Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
620 Texts. A copy of the license is included in the section entitled "GNU
621 Free Documentation License".
622binutils-2.18.90 2008-09-10 OBJCOPY(1)