OBJCOPY(1) GNU Development Tools OBJCOPY(1)NAMEobjcopy - copy and translate object files
SYNOPSISobjcopy [-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]
DESCRIPTION
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 recog‐
nize most formats without being told explicitly.
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 endian‐
ness or which have no endianness (e.g., srec).
OPTIONS
infile
outfile
The input 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.
-I bfdname
--input-target=bfdname
Consider the source file's object format to be bfdname, rather than
attempting to deduce it.
-O bfdname
--output-target=bfdname
Write the output file using the object format bfdname.
-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.
-B bfdarch
--binary-architecture=bfdarch
Useful when transforming a raw binary input file into an object
file. In this case the output architecture can be set to bfdarch.
This option will be ignored if the input file has a known bfdarch.
You can access this binary data inside a program by referencing the
special symbols that are created by the conversion process. These
symbols are called _binary_objfile_start, _binary_objfile_end and
_binary_objfile_size. e.g. you can transform a picture file into
an object file and then access it in your code using these symbols.
-j sectionname
--only-section=sectionname
Copy only the named section from the input file to the output file.
This option may be given more than once. Note that using this
option inappropriately may make the output file unusable.
-R sectionname
--remove-section=sectionname
Remove any section named sectionname from the output file. This
option may be given more than once. Note that 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 or sections 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.
-G symbolname
--keep-global-symbol=symbolname
Keep only symbol symbolname global. Make all other symbols local
to the file, so that they are not visible externally. This option
may be given more than once.
-L symbolname
--localize-symbol=symbolname
Make symbol symbolname local to the file, so that it is not visible
externally. This option may be given more than once.
-W symbolname
--weaken-symbol=symbolname
Make symbol symbolname weak. This option may be given more than
once.
-w
--wildcard
Permit regular expressions in symbolnames used in other command
line options. The question mark (?), asterisk (*), backslash (\)
and square brackets ([]) operators can be used anywhere in the sym‐
bol name. If the first character of the symbol name is the excla‐
mation point (!) then the sense of the switch is reversed for that
symbol. For example:
-w -W !foo -W fo*
would cause objcopy to weaken all symbols that start with ``fo''
except for the symbol ``foo''.
-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.
-p
--preserve-dates
Set the access and modification dates of the output file to be the
same as those of the input file.
--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 operation applies to the
load address (LMA) of the sections. It 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 load 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 start address of the new file to val. Not all object file
formats support setting the start address.
--change-start incr
--adjust-start incr
Change the start address by adding incr. Not all object file for‐
mats support setting the start address.
--change-addresses incr
--adjust-vma incr
Change the VMA and LMA addresses 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.
--change-section-address section{=,+,-}val
--adjust-section-vma section{=,+,-}val
Set or change both the VMA address and the LMA address of the named
section. If = is used, the section address is set to val. Other‐
wise, 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
Set or change the LMA address of the named section. The LMA
address is the address where the section will be loaded into memory
at program load time. Normally this is the same as the VMA
address, which is the address of the section at program run time,
but on some systems, especially those where a program is held in
ROM, the two can be different. 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 --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
Set or change the VMA address of the named section. The VMA
address is the address where the section will be located once the
program has started executing. Normally this is the same as the
LMA address, which is the address where the section will be loaded
into memory, but on some systems, especially those where a program
is held in ROM, the two can be different. If = is used, the sec‐
tion address is set to val. Otherwise, val is added to or sub‐
tracted 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
If --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
Do not issue a warning if --change-section-address or --adjust-sec‐
tion-lma or --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,
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
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.
--rename-section oldname=newname[,flags]
Rename a section from oldname to newname, optionally changing the
section's flags to flags in the process. This has the advantage
over usng a linker script to perform the rename in that the output
stays as an object file and does not become a linked executable.
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
Some object file formats use special characters at the start of
symbols. The most common such character is underscore, which com‐
pilers often add before every symbol. This option tells 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
If the first character of a global symbol is a special symbol lead‐
ing 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 differ‐
ent file formats with different conventions for symbol names. This
is different from --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
Meaningful only for srec output. Set the maximum length of the
Srecords being produced to ival. This length covers both address,
data and crc fields.
--srec-forceS3
Meaningful only for srec output. Avoid generation of S1/S2
records, creating S3-only record format.
--redefine-sym old=new
Change the name of a symbol old, to new. This can be useful when
one is trying link two things together for which you have no
source, and there are name collisions.
--redefine-syms=filename
Apply --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 charac‐
ter. This option may be given more than once.
--weaken
Change all global symbols in the file to be weak. This can be use‐
ful when building an object which will be linked against other
objects using the -R option to the linker. This option is only
effective when using an object file format which supports weak sym‐
bols.
--keep-symbols=filename
Apply --keep-symbol option to each symbol listed in the file file‐
name. 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
Apply --strip-symbol option to each symbol listed in the file file‐
name. 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
Apply --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
Apply --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
Apply --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
If the output architecture has alternate machine codes, use the
indexth code instead of the default one. This is useful in case a
machine is assigned an official code and the tool-chain adopts the
new code, but other applications still depend on the original code
being used.
--writable-text
Mark the output text as writable. This option isn't meaningful for
all object file formats.
--readonly-text
Make the output text write protected. This option isn't meaningful
for all object file formats.
--pure
Mark the output file as demand paged. This option isn't meaningful
for all object file formats.
--impure
Mark the output file as impure. This option isn't meaningful for
all object file formats.
--prefix-symbols=string
Prefix all symbols in the output file with string.
--prefix-sections=string
Prefix all section names in the output file with string.
--prefix-alloc-sections=string
Prefix all the names of all allocated sections in the output file
with string.
--add-gnu-debuglink=path-to-file
Creates a .gnu_debuglink section which contains a reference to
path-to-file and adds it to the output file.
--only-keep-debug
Strip a file, removing any sections that would be stripped by
--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 dis‐
tribution and the second a debugging information file which is only
needed if debugging abilities are required. The suggested proce‐
dure to create these files is as follows:
1.<Link the executable as normal. Assuming that is is called>
"foo" then...
1.<Run "objcopy --only-keep-debug foo foo.dbg" to>
create a file containing the debugging info.
1.<Run "objcopy --strip-debug foo" to create a>
stripped executable.
1.<Run "objcopy --add-gnu-debuglink=foo.dbg foo">
to add a link to the debugging info into the stripped exe‐
cutable.
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:
1.<Link the executable as normal.>
1.<Copy "foo" to "foo.full">
1.<Run "objcopy --strip-debug foo">
1.<Run "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
Show the version number of objcopy.
-v
--verbose
Verbose output: list all object files modified. In the case of ar‐
chives, objcopy-V lists all members of the archive.
--help
Show a summary of the options to objcopy.
--info
Display a list showing all architectures and object formats avail‐
able.
SEE ALSOld(1), objdump(1), and the Info entries for binutils.
COPYRIGHT
Copyright (c) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002,
2003 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
binutils-2.14.91 2004-04-09 OBJCOPY(1)
