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
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,-P,-r,-R,-s,-S,-t,-T,-V,-x must be
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.
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.
Specify that the object-code format for the object files is
bfdname. This option may not be necessary; objdump can
automatically recognize many formats.
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.
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
Display debugging information. This attempts to parse STABS and
IEEE debugging format information stored in the file and print it
out using a C like syntax. If neither of these formats are found
this option falls back on the -W option to print any DWARF
information in the file.
Like -g, but the information is generated in a format compatible
with ctags tool.
Display the assembler mnemonics for the machine instructions from
objfile. This option only disassembles those sections which are
expected to contain instructions.
Like -d, but disassemble the contents of all sections, not just
those expected to contain instructions.
This option also has a subtle effect on the disassembly of
instructions in code sections. When option -d is in effect
objdump will assume that any symbols present in a code section
occur on the boundary between instructions and it will refuse to
disassemble across such a boundary. When option -D is in effect
however this assumption is supressed. This means that it is
possible for the output of -d and -D to differ if, for example,
data is stored in code sections.
If the target is an ARM architecture this switch also has the
effect of forcing the disassembler to decode pieces of data found
in code sections as if they were instructions.
When disassembling, print the complete address on each line.
This is the older disassembly format.
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
Display summary information from the overall header of each of
the objfile files.
When disassembling sections, whenever a symbol is displayed, also
display the file offset of the region of data that is about to be
dumped. If zeroes are being skipped, then when disassembly
resumes, tell the user how many zeroes were skipped and the file
offset of the location from where the disassembly resumes. When
dumping sections, display the file offset of the location from
where the dump starts.
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.
Display summary information from the section headers of the
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 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
Note, in some cases it is possible for a section to have both the
READONLY and the NOREAD attributes set. In such cases the NOREAD
attribute takes precedence, but objdump will report both since
the exact setting of the flag bits might be important.
Print a summary of the options to objdump and exit.
Display a list showing all architectures and object formats
available for specification with -b or -m.
Display information only for section name.
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.
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.
If the target is an ARM architecture then this switch has an
additional effect. It restricts the disassembly to only those
instructions supported by the architecture specified by machine.
If it is necessary to use this switch because the input file does
not contain any architecture information, but it is also desired
to disassemble all the instructions use -marm.
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-names-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 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
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.
Select disassembly for the given architecture.
Select between intel syntax mode and AT&T syntax mode.
Select between AMD64 ISA and Intel64 ISA.
Select between intel mnemonic mode and AT&T mnemonic mode.
Note: "intel-mnemonic" implies "intel" and "att-mnemonic"
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.
When in AT&T mode, instructs the disassembler to print a
mnemonic suffix even when the suffix could be inferred by the
For PowerPC, booke controls the disassembly of BookE
instructions. 32 and 64 select PowerPC and PowerPC64
disassembly, respectively. e300 selects disassembly for the e300
family. 440 selects disassembly for the PowerPC 440. ppcps
selects disassembly for the paired single instructions of the
For MIPS, this option controls the printing of instruction
mnemonic 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:
Print the 'raw' instruction mnemonic instead of some pseudo
instruction mnemonic. I.e., print 'daddu' or 'or' instead of
'move', 'sll' instead of 'nop', etc.
Disassemble MSA instructions.
Disassemble the virtualization ASE instructions.
Disassemble the eXtended Physical Address (XPA) ASE
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.
Print FPR (floating-point register) names as appropriate for
the specified ABI. By default, FPR numbers are printed
rather than names.
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
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
Print GPR and FPR names as appropriate for the selected ABI.
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 -Mentry: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 rest of the function being wrongly disassembled.
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
Print information that is specific to the object file format.
The argument options is a comma separated list that depends on
the format (the lists of options is displayed with the help).
For XCOFF, the available options are:
Not all object formats support this option. In particular the
ELF format does not use it.
Print the relocation entries of the file. If used with -d or -D,
the relocations are printed interspersed with the disassembly.
Print the dynamic relocation entries of the file. This is only
meaningful for dynamic objects, such as certain types of shared
libraries. As for -r, if used with -d or -D, the relocations are
printed interspersed with the disassembly.
Display the full contents of any sections requested. By default
all non-empty sections are displayed.
Display source code intermixed with disassembly, if possible.
Specify prefix to add to the absolute paths when used with -S.
Indicate how many initial directory names to strip off the
hardwired absolute paths. It has no effect without
When disassembling instructions, print the instruction in hex as
well as in symbolic form. This is the default except when
--prefix-addresses is used.
When disassembling instructions, do not print the instruction
bytes. This is the default when --prefix-addresses is used.
Display width bytes on a single line when disassembling
Displays the contents of the debug sections in the file, if any
are present. If one of the optional letters or words follows the
switch then only data found in those specific sections will be
Note that there is no single letter option to display the content
of trace sections or .gdb_index.
Note: the output from the =info option can also be affected by
the options --dwarf-depth, the --dwarf-start and the
Limit the dump of the ".debug_info" section to n children. This
is only useful with --dwarf=info. The default is to print all
DIEs; the special value 0 for n will also have this effect.
With a non-zero value for n, DIEs at or deeper than n levels will
not be printed. The range for n is zero-based.
Print only DIEs beginning with the DIE numbered n. This is only
useful with --dwarf=info.
If specified, this option will suppress printing of any header
information and all DIEs before the DIE numbered n. Only
siblings and children of the specified DIE will be printed.
This can be used in conjunction with --dwarf-depth.
Enable additional checks for consistency of Dwarf information.
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 displaying data at the specified address. This affects the
output of the -d, -r and -s options.
Stop displaying data at the specified address. This affects the
output of the -d, -r and -s options.
Print the symbol table entries of the file. This is similar to
the information provided by the nm program, although the display
format is different. The format of the output depends upon the
format of the file being dumped, but there are two main types.
One looks like this:
[ 4](sec 3)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x00000000 .bss
[ 6](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000 fred
where the number inside the square brackets is the number of the
entry in the symbol table, the sec number is the section number,
the fl value are the symbol's flag bits, the ty number is the
symbol's type, the scl number is the symbol's storage class and
the nx value is the number of auxilary entries associated with
the symbol. The last two fields are the symbol's value and its
The other common output format, usually seen with ELF based
files, looks like this:
00000000 l d .bss 00000000 .bss
00000000 g .text 00000000 fred
Here the first number is the symbol's value (sometimes refered to
as its address). The next field is actually a set of characters
and spaces indicating the flag bits that are set on the symbol.
These characters are described below. Next is the section with
which the symbol is associated or *ABS* if the section is
absolute (ie not connected with any section), or *UND* if the
section is referenced in the file being dumped, but not defined
After the section name comes another field, a number, which for
common symbols is the alignment and for other symbol is the size.
Finally the symbol's name is displayed.
The flag characters are divided into 7 groups as follows:
"!" The symbol is a local (l), global (g), unique global (u),
neither global nor local (a space) or both global and local
(!). A symbol can be neither local or global for a variety
of reasons, e.g., because it is used for debugging, but it is
probably an indication of a bug if it is ever both local and
global. Unique global symbols are a GNU extension to the
standard set of ELF symbol bindings. For such a symbol the
dynamic linker will make sure that in the entire process
there is just one symbol with this name and type in use.
"w" The symbol is weak (w) or strong (a space).
"C" The symbol denotes a constructor (C) or an ordinary symbol (a
"W" The symbol is a warning (W) or a normal symbol (a space). A
warning symbol's name is a message to be displayed if the
symbol following the warning symbol is ever referenced.
"i" The symbol is an indirect reference to another symbol (I), a
function to be evaluated during reloc processing (i) or a
normal symbol (a space).
"D" The symbol is a debugging symbol (d) or a dynamic symbol (D)
or a normal symbol (a space).
"O" The symbol is the name of a function (F) or a file (f) or an
object (O) or just a normal symbol (a space).
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.
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.
Print the version number of objdump and exit.
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.
Format some lines for output devices that have more than 80
columns. Also do not truncate symbol names when they are
Normally the disassembly output will skip blocks of zeroes. This
option directs the disassembler to disassemble those blocks, just
like any other data.
Read command-line options from file. The options read are
inserted in place of the original @file option. If file does not
exist, or cannot be read, then the option will be treated
literally, and not removed.
Options in file are separated by whitespace. A whitespace
character may be included in an option by surrounding the entire
option in either single or double quotes. Any character
(including a backslash) may be included by prefixing the
character to be included with a backslash. The file may itself
contain additional @file options; any such options will be
Copyright (c) 1991-2016 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 1.3 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".
This page is part of the binutils (a collection of tools for working
with executable binaries) project. Information about the project can
be found at ⟨http://www.gnu.org/software/binutils/⟩. If you have a
bug report for this manual page, see
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binutils-2.26.51 2016-07-16 OBJDUMP(1)