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objdump(1) - phpMan
OBJDUMP(1) GNU Development Tools OBJDUMP(1)
NAME
objdump - display information from object files.
SYNOPSIS
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]
[-F|--file-offsets]
[--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]
[-P options|--private=options]
[-r|--reloc]
[-R|--dynamic-reloc]
[-s|--full-contents]
[-W[lLiaprmfFsoRt]|
--dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index]]
[-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]
[--prefix=prefix]
[--prefix-strip=level]
[--insn-width=width]
[-V|--version]
[-H|--help]
objfile...
DESCRIPTION
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.
OPTIONS
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
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 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.
-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.
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.
--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.
-F
--file-offsets
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.
--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 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.
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.
-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-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 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.
intel-mnemonic and att-mnemonic select between intel mnemonic mode and AT&T mnemonic
mode. intel-mnemonic implies intel and att-mnemonic implies att. addr64, 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 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 PPC750CL.
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:
"no-aliases"
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.
"msa"
Disassemble MSA instructions.
"virt"
Disassemble the virtualization ASE instructions.
"xpa"
Disassemble the eXtended Physical Address (XPA) ASE instructions.
"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"
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 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.
-P options
--private=options
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: header, aout, sections, syms, relocs, lineno,
loader, except, typchk, traceback, toc and ldinfo.
-r
--reloc
Print the relocation entries of the file. If used with -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. As for -r, if used with -d or -D,
the relocations are printed interspersed with the disassembly.
-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.
--prefix=prefix
Specify prefix to add to the absolute paths when used with -S.
--prefix-strip=level
Indicate how many initial directory names to strip off the hardwired absolute paths.
It has no effect without --prefix=prefix.
--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.
--insn-width=width
Display width bytes on a single line when disassembling instructions.
-W[lLiaprmfFsoRt]
--dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index]
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 dumped.
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 --dwarf-check.
--dwarf-depth=n
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.
--dwarf-start=n
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.
--dwarf-check
Enable additional checks for consistency of Dwarf information.
-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, 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 name.
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 there.
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:
"l"
"g"
"u"
"!" 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 space).
"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"
"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"
"D" The symbol is a debugging symbol (d) or a dynamic symbol (D) or a normal symbol (a
space).
"F"
"f"
"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).
-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.
@file
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 processed recursively.
SEE ALSO
nm(1), readelf(1), and the Info entries for binutils.
COPYRIGHT
Copyright (c) 1991-2014 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".
binutils-2.25 2014-12-23 OBJDUMP(1)
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