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.
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 in Using
ld.
objcopy
can be used to generate S-records
by using an output target of srec
(e.g., use -Osrec).
objcopy
can be used to generate a raw binary file by using an output target of
binary
(e.g., use -Obinary).
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 virtual 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 which is not
needed by the binary file.
infile outfile
The source and output files,
respectively. If you do not specify outfile,
objcopy
creates a temporary file and destructively renames the result with the
name of infile.
-Ibfdname --input-target=bfdname
Consider the source files
object format to be bfdname,
rather than attempting to deduce it. See Target
selection for more information.
-Obfdname --output-target=bfdname
Write the output file using
the object format bfdname.
See Target selection
for more information.
-F bfdname --target=bfdname
Use bfdname
as the object format for both the input and the output file; i.e., simply
transfer data from source to destination with no translation. See Target
selection for more information.
-R sectionname --remove-section=sectionname
Remove any section named
sectionname
from the output file. This option may be given more than once.
Note:
Using this option inappropriately
may make the output file unusable.
-S
--strip-all
Do not copy relocation and
symbol information from the source file.
-g
--strip-debug
Do not copy debugging symbols
from the source file.
--strip-unneeded
Strip all symbols that are
not needed for relocation processing.
-K symbolname --keep-symbol=symbolname
Copy only symbol symbolname
from the source file. This option may be given more than once.
-N symbolname --strip-symbol=symbolname
Do not copy symbol symbolname
from the source file. This option may be given more than once, and may
be combined with strip options other than -K.
-x
--discard-all
Do not copy non-global symbols
from the source file.
-X
--discard-locals
Do not copy compiler-generated
local symbols. (These usually start with L
or ..)
-b byte --byte=byte
Keep only every byteth
byte of the input file (header data is not affected). byte
can be in the range from 0 to interleave-1,
where interleave is given by the -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
Only copy one out of every
interleave
bytes. Select which byte to copy with the -b
or --byte
option. The default is 4. objcopy
ignores this option if you do not specify either -b
or --byte.
--debugging
Convert debugging information,
if possible. This is not the default because only certain debugging formats
are supported, and the conversion process can be time consuming.
--gap-fill val
Fill gaps between sections
with val.
This is done by increasing the size of the section with the lower address,
and filling in the extra space created with val.
--pad-to address
Pad the output file up to
the virtual address, address.
This is done by increasing the size of the last section. The extra space
is filled in with the value specified by --gap-fill
(default zero).
--set-start val
Set the address of the new
file to val.
Not all object file formats support setting the start address.
--adjust-start incr
Adjust the start address
by adding incr.
Not all object file formats support setting the start address.
--adjust-vma incr
Adjust the address of all
sections, as well as the start address, by adding incr.
Some object file formats do not permit section addresses to be changed
arbitrarily. Note that this does not relocate the sections; if the program
expects sections to be loaded at a certain address, and this option is
used to change the sections such that they are loaded at a different address,
the program may fail.
--adjust-section-vma section{=,+,-}val
Set or adjust the address
of the named section.
If =
is used, the section address is set to val.
Otherwise, val
is added to or subtracted from the section address. See the comments under
--adjust-vma.
If section
does not exist in the input file, a warning will be issued, unless --no-adjust-warnings
is used.
--adjust-warnings
If --adjust-section-vma
is used, and the named section does not exist, issue a warning. This is
the default.
--no-adjust-warnings
Do not issue a warning if
--adjust-section-vma
is used, even if the named section does not exist.
--set-section-flags section=flags
Set the flags for the named
section. The flags
argument is a comma separated string of flag names. The recognized names
are alloc,
load,
readonly,
code,
data,
and rom.
Not all flags are meaningful for all object file formats.
--add-section sectionname=filename
Add a new section named
sectionname
while copying the file. The contents of the new section are taken from
the file filename.
The size of the section will be the size of the file. This option only
works on file formats which can support sections with arbitrary names.
--remove-leading-char
If the first character of
a global symbol is a special symbol leading character used by the object
file format, remove the character. The most common symbol leading character
is underscore. This option will remove a leading underscore from all global
symbols. This can be useful if you want to link together objects of different
file formats with different conventions for symbol names.
-V
--version
Show the version number
of objcopy.
-v
--verbose
Verbose output: list all
object files modified. In the case of archives, objcopy
-V lists all
members of the archive.
