OBJDUMP(1) GNU Development Tools OBJDUMP(1)
objdump - display information from object files.
objdump [-a|--archive-headers]
[-b bfdname|--target=bfdname]
[-C|--demangle[=style] ]
[-d|--disassemble]
[-D|--disassemble-all]
[-z|--disassemble-zeroes]
[-EB|-EL|--endian={big | little }]
[-f|--file-headers]
[--file-start-context]
[-g|--debugging]
[-e|--debugging-tags]
[-h|--section-headers|--headers]
[-i|--info]
[-j section|--section=section]
[-l|--line-numbers]
[-S|--source]
[-m machine|--architecture=machine]
[-M options|--disassembler-options=options]
[-p|--private-headers]
[-r|--reloc]
[-R|--dynamic-reloc]
[-s|--full-contents]
[-G|--stabs]
[-t|--syms]
[-T|--dynamic-syms]
[-x|--all-headers]
[-w|--wide]
[--start-address=address]
[--stop-address=address]
[--prefix-addresses]
[--[no-]show-raw-insn]
[--adjust-vma=offset]
[--special-syms]
[-V|--version]
[-H|--help]
objfile...
objdump displays information about one or more object files.
The options control what particular information to display.
This information is mostly useful to programmers who are
working on the compilation tools, as opposed to programmers
who just want their program to compile and work.
objfile... are the object files to be examined. When you
specify archives, objdump shows information on each of the
member object files.
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The long and short forms of options, shown here as
alternatives, are equivalent. At least one option from the
list -a,-d,-D,-e,-f,-g,-G,-h,-H,-p,-r,-R,-s,-S,-t,-T,-V,-x
must be given.
-a
--archive-header
If any of the objfile files are archives, display the
archive header information (in a format similar to ls
-l). Besides the information you could list with ar tv,
objdump -a shows the object file format of each archive
member.
--adjust-vma=offset
When dumping information, first add offset to all the
section addresses. This is useful if the section
addresses do not correspond to the symbol table, which
can happen when putting sections at particular addresses
when using a format which can not represent section
addresses, such as a.out.
-b bfdname
--target=bfdname
Specify that the object-code format for the object files
is bfdname. This option may not be necessary; objdump
can automatically recognize many formats.
For example,
objdump -b oasys -m vax -h fu.o
displays summary information from the section headers
(-h) of fu.o, which is explicitly identified (-m) as a
VAX object file in the format produced by Oasys
compilers. You can list the formats available with the
-i option.
-C
--demangle[=style]
Decode (demangle) low-level symbol names into user-level
names. Besides removing any initial underscore prepended
by the system, this makes C++ function names readable.
Different compilers have different mangling styles. The
optional demangling style argument can be used to choose
an appropriate demangling style for your compiler.
-g
--debugging
Display debugging information. This attempts to parse
debugging information stored in the file and print it
out using a C like syntax. Only certain types of
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debugging information have been implemented. Some other
types are supported by readelf -w.
-e
--debugging-tags
Like -g, but the information is generated in a format
compatible with ctags tool.
-d
--disassemble
Display the assembler mnemonics for the machine
instructions from objfile. This option only
disassembles those sections which are expected to
contain instructions.
-D
--disassemble-all
Like -d, but disassemble the contents of all sections,
not just those expected to contain instructions.
--prefix-addresses
When disassembling, print the complete address on each
line. This is the older disassembly format.
-EB
-EL
--endian={big|little}
Specify the endianness of the object files. This only
affects disassembly. This can be useful when
disassembling a file format which does not describe
endianness information, such as S-records.
-f
--file-headers
Display summary information from the overall header of
each of the objfile files.
--file-start-context
Specify that when displaying interlisted source
code/disassembly (assumes -S) from a file that has not
yet been displayed, extend the context to the start of
the file.
-h
--section-headers
--headers
Display summary information from the section headers of
the object file.
File segments may be relocated to nonstandard addresses,
for example by using the -Ttext, -Tdata, or -Tbss
options to ld. However, some object file formats, such
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as a.out, do not store the starting address of the file
segments. In those situations, although ld relocates
the sections correctly, using objdump -h to list the
file section headers cannot show the correct addresses.
Instead, it shows the usual addresses, which are
implicit for the target.
-H
--help
Print a summary of the options to objdump and exit.
-i
--info
Display a list showing all architectures and object
formats available for specification with -b or -m.
-j name
--section=name
Display information only for section name.
-l
--line-numbers
Label the display (using debugging information) with the
filename and source line numbers corresponding to the
object code or relocs shown. Only useful with -d, -D, or
-r.
-m machine
--architecture=machine
Specify the architecture to use when disassembling
object files. This can be useful when disassembling
object files which do not describe architecture
information, such as S-records. You can list the
available architectures with the -i option.
-M options
--disassembler-options=options
Pass target specific information to the disassembler.
Only supported on some targets. If it is necessary to
specify more than one disassembler option then multiple
-M options can be used or can be placed together into a
comma separated list.
If the target is an ARM architecture then this switch
can be used to select which register name set is used
during disassembler. Specifying -M reg-name-std (the
default) will select the register names as used in ARM's
instruction set documentation, but with register 13
called 'sp', register 14 called 'lr' and register 15
called 'pc'. Specifying -M reg-names-apcs will select
the name set used by the ARM Procedure Call Standard,
whilst specifying -M reg-names-raw will just use r
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followed by the register number.
There are also two variants on the APCS register naming
scheme enabled by -M reg-names-atpcs and -M reg-names-
special-atpcs which use the ARM/Thumb Procedure Call
Standard naming conventions. (Either with the normal
register names or the special register names).
This option can also be used for ARM architectures to
force the disassembler to interpret all instructions as
Thumb instructions by using the switch
--disassembler-options=force-thumb. This can be useful
when attempting to disassemble thumb code produced by
other compilers.
For the x86, some of the options duplicate functions of
the -m switch, but allow finer grained control.
Multiple selections from the following may be specified
as a comma separated string. x86-64, i386 and i8086
select disassembly for the given architecture. intel
and att select between intel syntax mode and AT&T syntax
mode. addr32, addr16, data32 and data16 specify the
default address size and operand size. These four
options will be overridden if x86-64, i386 or i8086
appear later in the option string. Lastly, suffix, when
in AT&T mode, instructs the disassembler to print a
mnemonic suffix even when the suffix could be inferred
by the operands.
For PPC, booke, booke32 and booke64 select disassembly
of BookE instructions. 32 and 64 select PowerPC and
PowerPC64 disassembly, respectively.
For MIPS, this option controls the printing of
instruction mneumonic names and register names in
disassembled instructions. Multiple selections from the
following may be specified as a comma separated string,
and invalid options are ignored:
"no-aliases"
Print the 'raw' instruction mneumonic instead of
some pseudo instruction mneumonic. I.E. print
'daddu' or 'or' instead of 'move', 'sll' instead of
'nop', etc.
"gpr-names=ABI"
Print GPR (general-purpose register) names as
appropriate for the specified ABI. By default, GPR
names are selected according to the ABI of the
binary being disassembled.
"fpr-names=ABI"
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Print FPR (floating-point register) names as
appropriate for the specified ABI. By default, FPR
numbers are printed rather than names.
"cp0-names=ARCH"
Print CP0 (system control coprocessor; coprocessor
0) register names as appropriate for the CPU or
architecture specified by ARCH. By default, CP0
register names are selected according to the
architecture and CPU of the binary being
disassembled.
"hwr-names=ARCH"
Print HWR (hardware register, used by the "rdhwr"
instruction) names as appropriate for the CPU or
architecture specified by ARCH. By default, HWR
names are selected according to the architecture and
CPU of the binary being disassembled.
"reg-names=ABI"
Print GPR and FPR names as appropriate for the
selected ABI.
"reg-names=ARCH"
Print CPU-specific register names (CP0 register and
HWR names) as appropriate for the selected CPU or
architecture.
For any of the options listed above, ABI or ARCH may be
specified as numeric to have numbers printed rather than
names, for the selected types of registers. You can list
the available values of ABI and ARCH using the --help
option.
For VAX, you can specify function entry addresses with
-M entry:0xf00ba. You can use this multiple times to
properly disassemble VAX binary files that don't contain
symbol tables (like ROM dumps). In these cases, the
function entry mask would otherwise be decoded as VAX
instructions, which would probably lead the the rest of
the function being wrongly disassembled.
-p
--private-headers
Print information that is specific to the object file
format. The exact information printed depends upon the
object file format. For some object file formats, no
additional information is printed.
-r
--reloc
Print the relocation entries of the file. If used with
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-d or -D, the relocations are printed interspersed with
the disassembly.
-R
--dynamic-reloc
Print the dynamic relocation entries of the file. This
is only meaningful for dynamic objects, such as certain
types of shared libraries.
-s
--full-contents
Display the full contents of any sections requested. By
default all non-empty sections are displayed.
-S
--source
Display source code intermixed with disassembly, if
possible. Implies -d.
--show-raw-insn
When disassembling instructions, print the instruction
in hex as well as in symbolic form. This is the default
except when --prefix-addresses is used.
--no-show-raw-insn
When disassembling instructions, do not print the
instruction bytes. This is the default when
--prefix-addresses is used.
-G
--stabs
Display the full contents of any sections requested.
Display the contents of the .stab and .stab.index and
.stab.excl sections from an ELF file. This is only
useful on systems (such as Solaris 2.0) in which ".stab"
debugging symbol-table entries are carried in an ELF
section. In most other file formats, debugging symbol-
table entries are interleaved with linkage symbols, and
are visible in the --syms output.
--start-address=address
Start displaying data at the specified address. This
affects the output of the -d, -r and -s options.
--stop-address=address
Stop displaying data at the specified address. This
affects the output of the -d, -r and -s options.
-t
--syms
Print the symbol table entries of the file. This is
similar to the information provided by the nm program.
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-T
--dynamic-syms
Print the dynamic symbol table entries of the file.
This is only meaningful for dynamic objects, such as
certain types of shared libraries. This is similar to
the information provided by the nm program when given
the -D (--dynamic) option.
--special-syms
When displaying symbols include those which the target
considers to be special in some way and which would not
normally be of interest to the user.
-V
--version
Print the version number of objdump and exit.
-x
--all-headers
Display all available header information, including the
symbol table and relocation entries. Using -x is
equivalent to specifying all of -a -f -h -p -r -t.
-w
--wide
Format some lines for output devices that have more than
80 columns. Also do not truncate symbol names when they
are displayed.
-z
--disassemble-zeroes
Normally the disassembly output will skip blocks of
zeroes. This option directs the disassembler to
disassemble those blocks, just like any other data.
nm(1), readelf(1), and the Info entries for binutils.
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1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 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''.
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