File: binutils.info, Node: objcopy, Next: objdump, Prev: nm, Up: Top
3 objcopy
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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. *Note BFD:
(ld.info)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').
`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. *Note Target Selection::, for more
information.
`-O BFDNAME'
`--output-target=BFDNAME'
Write the output file using the object format BFDNAME. *Note
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. *Note Target Selection::, for more information.
`-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
symbol name. If the first character of the symbol name is the
exclamation 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
formats 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.
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'
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
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'
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-section-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
compilers 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
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. 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
character. This option may be given more than once.
`--weaken'
Change all global symbols in the file to be weak. This can be
useful 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
symbols.
`--keep-symbols=FILENAME'
Apply `--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'
Apply `--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'
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
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:
1. Link the executable as normal. Assuming that is is called
`foo' then...
2. Run `objcopy --only-keep-debug foo foo.dbg' to create a file
containing the debugging info.
3. Run `objcopy --strip-debug foo' to create a stripped
executable.
4. Run `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:
1. Link the executable as normal.
2. Copy `foo' to `foo.full'
3. Run `objcopy --strip-debug foo'
4. 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
archives, `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
available.
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