objcopy [-F
bfdname|--target=
bfdname] [-I
bfdname|--input-target=
bfdname] [-O
bfdname|--output-target=
bfdname] [-B
bfdarch|--binary-architecture=
bfdarch] [-S
|--strip-all
] [-g
|--strip-debug
] [-K
symbolname|--keep-symbol=
symbolname] [-N
symbolname|--strip-symbol=
symbolname] [-G
symbolname|--keep-global-symbol=
symbolname] [-L
symbolname|--localize-symbol=
symbolname] [-W
symbolname|--weaken-symbol=
symbolname] [-w
|--wildcard
] [-x
|--discard-all
] [-X
|--discard-locals
] [-b
byte|--byte=
byte] [-i
interleave|--interleave=
interleave] [-j
sectionname|--only-section=
sectionname] [-R
sectionname|--remove-section=
sectionname] [-p
|--preserve-dates
] [--debugging
] [--gap-fill=
val] [--pad-to=
address] [--set-start=
val] [--adjust-start=
incr] [--change-addresses=
incr] [--change-section-address
section{=,+,-}val] [--change-section-lma
section{=,+,-}val] [--change-section-vma
section{=,+,-}val] [--change-warnings
] [--no-change-warnings
] [--set-section-flags
section=flags] [--add-section
sectionname=filename] [--rename-section
oldname=newname[,flags]] [--change-leading-char
] [--remove-leading-char
] [--srec-len=
ival] [--srec-forceS3
] [--redefine-sym
old=new] [--redefine-syms=
filename] [--weaken
] [--keep-symbols=
filename] [--strip-symbols=
filename] [--keep-global-symbols=
filename] [--localize-symbols=
filename] [--weaken-symbols=
filename] [--alt-machine-code=
index] [--prefix-symbols=
string] [--prefix-sections=
string] [--prefix-alloc-sections=
string] [--add-gnu-debuglink=
path-to-file] [--only-keep-debug
] [--writable-text
] [--readonly-text
] [--pure
] [--impure
] [-v
|--verbose
] [-V
|--version
] [--help
] [--info
] infile [outfile]
The GNU objcopy
utility copies the contents of an object file to another. objcopy
uses the GNU BFD Library to read and write the object files. It can write the destination object file in a format different from that of the source object file. The exact behavior of objcopy
is controlled by command-line options. Note that objcopy
should be able to copy a fully linked file between any two formats. However, copying a relocatable object file between any two formats may not work as expected.
objcopy
creates temporary files to do its translations and deletes them afterward. objcopy
uses BFD to do all its translation work; it has access to all the formats described in BFD and thus is able to recognize most formats without being told explicitly. See BFD.
objcopy
can be used to generate S-records by using an output target of srec
(e.g., use -O srec
).
objcopy
can be used to generate a raw binary file by using an output target of binary
(e.g., use -O binary
). When objcopy
generates a raw binary file, it will essentially produce a memory dump of the contents of the input object file. All symbols and relocation information will be discarded. The memory dump will start at the load address of the lowest section copied into the output file.
When generating an S-record or a raw binary file, it may be helpful to use -S
to remove sections containing debugging information. In some cases -R
will be useful to remove sections which contain information that is not needed by the binary file.
Note--objcopy
is not able to change the endianness of its input files. If the input format has an endianness (some formats do not), objcopy
can only copy the inputs into file formats that have the same endianness or which have no endianness (e.g., srec
).
objcopy
creates a temporary file and destructively renames the result with the name of infile.-I
bfdname--input-target=
bfdname-O
bfdname--output-target=
bfdname-F
bfdname--target=
bfdname-B
bfdarch--binary-architecture=
bfdarch-j
sectionname--only-section=
sectionname-R
sectionname--remove-section=
sectionname-S
--strip-all
-g
--strip-debug
--strip-unneeded
-K
symbolname--keep-symbol=
symbolname-N
symbolname--strip-symbol=
symbolname-G
symbolname--keep-global-symbol=
symbolname-L
symbolname--localize-symbol=
symbolname-W
symbolname--weaken-symbol=
symbolname-w
--wildcard
-w -W !foo -W fo*
would cause objcopy to weaken all symbols that start with "fo" except for the symbol "foo".
-x
--discard-all
-X
--discard-locals
L
or .
.)-b
byte--byte=
byte-i
or --interleave
option, or the default of 4. This option is useful for creating files to program ROM. It is typically used with an srec
output target.-i
interleave--interleave=
interleave-b
or --byte
option. The default is 4. objcopy
ignores this option if you do not specify either -b
or --byte
.-p
--preserve-dates
--debugging
--gap-fill
val--pad-to
address--gap-fill
(default zero).--set-start
val--change-start
incr--adjust-start
incr--change-addresses
incr--adjust-vma
incr--change-section-address
section{=,+,-}
val--adjust-section-vma
section{=,+,-}
val=
is used, the section address is set to val. Otherwise, val is added to or subtracted from the section address. See the comments under --change-addresses
, above. If section does not exist in the input file, a warning will be issued, unless --no-change-warnings
is used.--change-section-lma
section{=,+,-}
val=
is used, the section address is set to val. Otherwise, val is added to or subtracted from the section address. See the comments under --change-addresses
, above. If section does not exist in the input file, a warning will be issued, unless --no-change-warnings
is used.--change-section-vma
section{=,+,-}
val=
is used, the section address is set to val. Otherwise, val is added to or subtracted from the section address. See the comments under --change-addresses
, above. If section does not exist in the input file, a warning will be issued, unless --no-change-warnings
is used.--change-warnings
--adjust-warnings
--change-section-address
or --change-section-lma
or --change-section-vma
is used, and the named section does not exist, issue a warning. This is the default.--no-change-warnings
--no-adjust-warnings
--change-section-address
or --adjust-section-lma
or --adjust-section-vma
is used, even if the named section does not exist.--set-section-flags
section=
flagsalloc
, contents
, load
, noload
, readonly
, code
, data
, rom
, share
, and debug
. You can set the contents
flag for a section which does not have contents, but it is not meaningful to clear the contents
flag of a section which does have contents-just remove the section instead. Not all flags are meaningful for all object file formats.--add-section
sectionname=
filename--rename-section
oldname=
newname[,
flags]
This option is particularly helpful when the input format is binary, since this will always create a section called .data. If for example, you wanted instead to create a section called .rodata containing binary data you could use the following command line to achieve it:
objcopy -I binary -O <output_format> -B <architecture> \ --rename-section .data=.rodata,alloc,load,readonly,data,contents \ <input_binary_file> <output_object_file>
--change-leading-char
objcopy
to change the leading character of every symbol when it converts between object file formats. If the object file formats use the same leading character, this option has no effect. Otherwise, it will add a character, or remove a character, or change a character, as appropriate.--remove-leading-char
--change-leading-char
because it always changes the symbol name when appropriate, regardless of the object file format of the output file.--srec-len=
ival--srec-forceS3
--redefine-sym
old=
new--redefine-syms=
filename--redefine-sym
to each symbol pair "old new" listed in the file filename. filename is simply a flat file, with one symbol pair per line. Line comments may be introduced by the hash character. This option may be given more than once.--weaken
-R
option to the linker. This option is only effective when using an object file format which supports weak symbols.--keep-symbols=
filename--keep-symbol
option to each symbol listed in the file filename. filename is simply a flat file, with one symbol name per line. Line comments may be introduced by the hash character. This option may be given more than once.--strip-symbols=
filename--strip-symbol
option to each symbol listed in the file filename. filename is simply a flat file, with one symbol name per line. Line comments may be introduced by the hash character. This option may be given more than once.--keep-global-symbols=
filename--keep-global-symbol
option to each symbol listed in the file filename. filename is simply a flat file, with one symbol name per line. Line comments may be introduced by the hash character. This option may be given more than once.--localize-symbols=
filename--localize-symbol
option to each symbol listed in the file filename. filename is simply a flat file, with one symbol name per line. Line comments may be introduced by the hash character. This option may be given more than once.--weaken-symbols=
filename--weaken-symbol
option to each symbol listed in the file filename. filename is simply a flat file, with one symbol name per line. Line comments may be introduced by the hash character. This option may be given more than once.--alt-machine-code=
index--writable-text
--readonly-text
--pure
--impure
--prefix-symbols=
string--prefix-sections=
string--prefix-alloc-sections=
string--add-gnu-debuglink=
path-to-file--only-keep-debug
--strip-debug
and leaving the debugging sections.
The intention is that this option will be used in conjunction with --add-gnu-debuglink
to create a two part executable. One a stripped binary which will occupy less space in RAM and in a distribution and the second a debugging information file which is only needed if debugging abilities are required. The suggested procedure to create these files is as follows:
foo
then...objcopy --only-keep-debug foo foo.dbg
to create a file containing the debugging info.objcopy --strip-debug foo
to create a stripped executable.objcopy --add-gnu-debuglink=foo.dbg foo
to add a link to the debugging info into the stripped executable.Note - the choice of .dbg
as an extension for the debug info file is arbitrary. Also the --only-keep-debug
step is optional. You could instead do this:
foo
to foo.full
objcopy --strip-debug foo
objcopy --add-gnu-debuglink=foo.full foo
ie the file pointed to by the --add-gnu-debuglink
can be the full executable. It does not have to be a file created by the --only-keep-debug
switch.
-V
--version
objcopy
.-v
--verbose
objcopy -V
lists all members of the archive.--help
objcopy
.--info