OBJDUMP(1)

📦
version 2.45.50.20251209+3.5.3build1 · 5 versions
, in ubuntu resolute, ubuntu stonking

✨ objdump(1) ✨

okay so bestie, welcome to objdump(1) from the GNU Development Tools collection 🫶 she's the queen of "what is even in this object file", and she will absolutely spill every detail. she displays information from object files, and she's not shy about it. 💅

🌸 NAME 🌸

objdump — display information from object files 💖 (yes that's the whole vibe, she shows you stuff inside object files, iconic behavior)

🎀 SYNOPSIS 🎀

objdump [-a|--archive-headers]
        [-b bfdname|--target=bfdname]
        [-C|--demangle[=style] ]
        [-d|--disassemble[=symbol]]
        [-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]
        [--source-comment[=text]]
        [-m machine|--architecture=machine]
        [-M options|--disassembler-options=options]
        [-p|--private-headers]
        [-P options|--private=options]
        [-r|--reloc]
        [-R|--dynamic-reloc]
        [-s|--full-contents]
        [-Z|--decompress]
        [-W[lLiaprmfFsoORtUuTgAck]|
         --dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=str-offsets,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index,=addr,=cu_index,=links]]
        [-WK|--dwarf=follow-links]
        [-WN|--dwarf=no-follow-links]
        [-wD|--dwarf=use-debuginfod]
        [-wE|--dwarf=do-not-use-debuginfod]
        [-L|--process-links]
        [--ctf=section]
        [--sframe=section]
        [-G|--stabs]
        [-t|--syms]
        [-T|--dynamic-syms]
        [-x|--all-headers]
        [-w|--wide]
        [--start-address=address]
        [--stop-address=address]
        [--no-addresses]
        [--prefix-addresses]
        [--[no-]show-raw-insn]
        [--adjust-vma=offset]
        [--show-all-symbols]
        [--dwarf-depth=n]
        [--dwarf-start=n]
        [--ctf-parent=section]
        [--no-recurse-limit|--recurse-limit]
        [--special-syms]
        [--prefix=prefix]
        [--prefix-strip=level]
        [--insn-width=width]
        [--visualize-jumps[=color|=extended-color|=off]
        [--disassembler-color=[off|terminal|on|extended]
        [-U method] [--unicode=method]
        [-V|--version]
        [-H|--help]
        objfile...

🦋 DESCRIPTION 🦋

so like, objdump displays information about one or more object files. the options control what particular information to display. ngl this info is mostly useful to programmers working on the compilation tools — as opposed to programmers who just want their program to compile and work. iykyk 🧚

objfile... are the object files to be examined. and when you specify archives, objdump shows information on each of the member object files. she does not skip anybody, everyone gets their moment ✨

💅 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. like, she needs something to do, she's not gonna just stand there 💀

  • -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. little extra detail, we love a bonus 🎀
  • --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 even be necessary; objdump can automatically recognize many formats. she's smart like that ✨

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. making C++ readable?? she's doing the lord's work fr fr 🙏
  • --recurse-limit, --no-recurse-limit, --recursion-limit, --no-recursion-limit — enables or disables a limit on the amount of recursion performed whilst demangling strings. since the name mangling formats allow for an infinite level of recursion it is possible to create strings whose decoding will exhaust the amount of stack space available on the host machine, triggering a memory fault. 😭 the limit tries to prevent this from happening by restricting recursion to 2048 levels of nesting.
the default is for this limit to be enabled, but disabling it may be necessary in order to demangle truly complicated names. note however that if the recursion limit is disabled then stack exhaustion is possible and any bug reports about such an event will be rejected. 💀 bestie do not come crying to the maintainers.
  • -g, --debugging — display debugging information. this attempts to parse STABS debugging format information stored in the file and print it out using a C like syntax. if no STABS debugging was found this option falls back on the -W option to print any DWARF information in the file. she has a plan B, always prepared 💖
  • -e, --debugging-tags — like -g, but the information is generated in a format compatible with the ctags tool. 🦋
  • -d, --disassemble, --disassemble=symbol — display the assembler mnemonics for the machine instructions from the input file. this option only disassembles those sections which are expected to contain instructions. if the optional symbol argument is given (perhaps multiple times), then display the assembler mnemonics starting at (all the) symbol. if symbol is a function name then disassembly will stop at the end of the function, otherwise it will stop when the next symbol is encountered. if there are no matches for any symbol then nothing will be displayed. 💀 (silence. the drama.)

note if the --dwarf=follow-links option is enabled then any symbol tables in linked debug info files will be read in and used when disassembling. 🔥

  • -D, --disassemble-all — like -d, but disassemble the contents of all non-empty non-bss sections, not just those expected to contain instructions. -j may be used to select specific sections. she's going feral, no gatekeeping 🌈

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 suppressed. 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. ARM said "no thoughts, just vibes" 🎀

note if the --dwarf=follow-links option is enabled then any symbol tables in linked debug info files will be read in and used when disassembling. 🔥

  • --no-addresses — when disassembling, don't print addresses on each line or for symbols and relocation offsets. in combination with --no-show-raw-insn this may be useful for comparing compiler output. clean. minimal. aesthetic ✨
  • --prefix-addresses — when disassembling, print the complete address on each line. this is the older disassembly format. vintage 💜
  • -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. receipts on receipts 🧾✨
  • --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. 😭 the format betrayed her, not her fault.

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. ⚠️

  • -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. the menu, basically 🍓
  • -j name, --section=name — display information for section name. this option may be specified multiple times. stack 'em up bestie 👑
  • -L, --process-links — display the contents of non-debug sections found in separate debuginfo files that are linked to the main file. this option automatically implies the -WK option, and only sections requested by other command line options will be displayed. 💜

and that's where part 1 wraps, bestie — there's more coming, don't go anywhere 🦋✨

  • -l, --line-numbers — bestie this one labels the display with the filename and source line numbers that match up to the object code or relocs shown, using the debugging info. Only useful with -d, -D, or -r tho, so don't come crying to me if it does nothing on its own 💅
  • -m machine, --architecture=machine — tells objdump which architecture to use when disassembling. Iconic when you're disassembling object files that don't describe architecture info at all, like S-records. You can peep the available architectures with the -i option ✨

For most architectures you can hand over an architecture name and a machine name separated by a colon. So like foo:bar would mean the bar machine type inside the foo architecture. Super helpful if objdump was configured to support multiple architectures 🫶

If the target is an ARM architecture, this switch does an extra thing: it restricts disassembly to only those instructions supported by the architecture specified by machine. And if you need this switch because your input file has no architecture info, but you still wanna disassemble ALL the instructions? Use -marm. periodt 🌸

  • -M options, --disassembler-options=options — passes target specific info to the disassembler. Only supported on some targets. If you need more than one disassembler option, either use multiple -M options or squish them together into a comma separated list. no cap 🎀

For ARC: dsp controls the printing of DSP instructions, spfp selects the printing of FPX single precision FP instructions, dpfp selects the printing of FPX double precision FP instructions, quarkse_em selects the printing of special QuarkSE-EM instructions, fpuda selects the printing of double precision assist instructions, fpus selects the printing of FPU single precision FP instructions, while fpud selects the printing of FPU double precision FP instructions. Also you can choose to have all the immediates printed in hexadecimal using hex. By default, the short immediates are printed using the decimal representation, while the long immediate values are printed as hexadecimal. the range honestly 💜

cpu=... lets you enforce a particular ISA when disassembling instructions, overriding the -m value or whatever is in the ELF file. This might be useful to select ARC EM or HS ISA, because architecture is same for those and the disassembler relies on private ELF header data to decide if code is for EM or HS. This option might be specified multiple times — only the latest value will be used. Valid values are same as for the assembler -mcpu=... option.

If the target is an ARM architecture then this switch can be used to select which register name set is used during disassembly. 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 AArch64 targets this switch can be used to set whether instructions are disassembled as the most general instruction using the -M no-aliases option or whether instruction notes should be generated as comments in the disasssembly using -M notes. ⭐

For the x86, some of the options duplicate functions of the -m switch, but allow finer grained control. 👑

  • "x86-64", "i386", "i8086" — Select disassembly for the given architecture.
  • "intel", "att" — Select between intel syntax mode and AT&T syntax mode.
  • "amd64", "intel64" — Select between AMD64 ISA and Intel64 ISA.
  • "intel-mnemonic", "att-mnemonic" — Select between intel mnemonic mode and AT&T mnemonic mode. Note: "intel-mnemonic" implies "intel" and "att-mnemonic" implies "att".
  • "addr64", "addr32", "addr16", "data32", "data16" — Specify the default address size and operand size. These five options will be overridden if "x86-64", "i386" or "i8086" appear later in the option string.
  • "suffix" — When in AT&T mode and also for a limited set of instructions when in Intel mode, instructs the disassembler to print a mnemonic suffix even when the suffix could be inferred by the operands or, for certain instructions, the execution mode's defaults.

For PowerPC, the -M argument raw selects disasssembly of hardware insns rather than aliases. So you'll see "rlwinm" rather than "clrlwi", and "addi" rather than "li". All of the -m arguments for gas that select a CPU are supported. These are: 403, 405, 440, 464, 476, 601, 603, 604, 620, 7400, 7410, 7450, 7455, 750cl, 821, 850, 860, a2, booke, booke32, cell, com, e200z2, e200z4, e300, e500, e500mc, e500mc64, e500x2, e5500, e6500, efs, power4, power5, power6, power7, power8, power9, power10, power11, ppc, ppc32, ppc64, ppc64bridge, ppcps, pwr, pwr2, pwr4, pwr5, pwr5x, pwr6, pwr7, pwr8, pwr9, pwr10, pwr11, pwrx, titan, vle, and future. 💅 32 and 64 modify the default or a prior CPU selection, disabling and enabling 64-bit insns respectively. In addition, altivec, any, lsp, htm, vsx, spe and spe2 add capabilities to a previous or later CPU selection. any will disassemble any opcode known to binutils, but in cases where an opcode has two different meanings or different arguments, you may not see the disassembly you expect. and if you disassemble without giving a CPU selection, a default will be chosen from information gleaned by BFD from the object files headers, but the result again may not be as you expect. 🙈

For RISC-V, the following options are supported: 🌈

  • "max" — Disassemble without checking architecture string. This is a best effort mode, so for overlapping ISA extensions the first match (possibly incorrect in a given context) will be used to decode the instruction. It's useful, if the ELF file doesn't expose ISA string, preventing automatic ISA subset deduction, and the default fallback ISA string ("rv64gc") doesn't cover all instructions in the binary.
  • "numeric" — Print numeric register names, rather than ABI names (e.g., print "x2" instead of "sp").
  • "no-aliases" — Disassemble only into canonical instructions. For example, compressed instructions will be represented as such ("addi sp,sp,-128" will be "c.addi16sp sp,-128").
  • "priv-spec=SPEC" — Print the CSR according to the chosen privilege spec version (e.g., 1.10, 1.11, 1.12, 1.13).

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. so like, use it, bestie 😭

  • -p, --private-headers — Prints info that's specific to the object file format. The exact info printed depends upon the object file format. and for some object file formats, no additional information is printed at all 💀
  • -P options, --private=options — Prints info 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: 🎀

so the names you can hand it for that format are:

"header"
"aout"
"sections"
"syms"
"relocs"
"lineno,"
"loader"
"except"
"typchk"
"traceback"
"toc"
"ldinfo"

and for PE, bestie, the options you get are just:

"header"
"sections"
lowkey important: not every object format supports this option. ELF in particular does not use it at all — so don't come crying to me when nothing happens. 💅
  • -r, --reloc — print the relocation entries of the file. And if you use it with -d or -D, the relocations get printed interspersed with the disassembly — like a lil mashup, we love to see it. ✨
  • -R, --dynamic-reloc — print the dynamic relocation entries of the file. This one only makes sense for dynamic objects, like certain types of shared libraries. And same as -r, if you use it with -d or -D, the relocations come out interspersed with the disassembly.
not me about to ruin your day: objdump does not support displaying RELR type relocations. If you need those, the readelf program can show them. sorry bestie 😭
  • -s, --full-contents — display the full contents of sections, usually paired up with -j when you want specific sections. By default it shows all non-empty non-bss sections. And by default, any compressed section is shown in its compressed form. Want to see it decompressed instead? Add the -Z option to the command line. 🫶
  • -S, --source — display source code mixed in with the disassembly, if it's possible. This implies -d. iconic behavior honestly.
  • --show-all-symbols — when disassembling, show all the symbols that match a given address, not just the first one. the way it stops gatekeeping info... 👑
  • --source-comment[=txt] — like the -S option, except every source code line gets a prefix of txt. Usually txt is a comment string so you can tell the assembler code apart from the source code. If txt isn't given, the default string is "# " (hash followed by a space). cute.
  • --prefix=prefix — specify prefix to add to the absolute paths when it's used with -S.
  • --prefix-strip=level — tell it how many initial directory names to strip off the hardwired absolute paths. Heads up: it does nothing without --prefix=prefix. fr fr.
  • --show-raw-insn — when disassembling instructions, print the instruction in hex and 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.
  • --visualize-jumps[=color|=extended-color|=off] — visualize jumps that stay inside a function by drawing ASCII art between the start and target addresses. The optional =color argument adds color to the output using simple terminal colors. Or, alternatively, the =extended-color argument adds color using 8bit colors — but those might not work on every terminal, so vibe check your setup first. 🌈

If you need to turn the visualize-jumps option back off after it's been enabled, use visualize-jumps=off.

  • --disassembler-color=off
  • --disassembler-color=terminal
  • --disassembler-color=on|color|colour
  • --disassembler-color=extended|extended-color|extended-colour

— turns colored syntax highlighting in the disassembly output on or off. The default behavior is decided by a configure time option. Note that not all architectures support colored syntax highlighting, and depending on the terminal you're using, the colored output might not actually be legible. 💀

The on argument adds colors using simple terminal colors.

The terminal argument does the same thing, but only if the output device is a terminal.

The extended-color argument is similar to the on argument, but it uses 8-bit colors. Those may not work on all terminals.

The off argument disables colored disassembly. periodt.

  • -W[lLiaprmfFsoORtUuTgAckK]
  • --dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=str-offsets,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index,=addr,=cu_index,=links,=follow-links]

— displays the contents of the DWARF debug sections in the file, if any are present. Compressed debug sections get automatically decompressed (temporarily) before they're displayed. And if one or more of the optional letters or words follows the switch, then only those type(s) of data get dumped. 🧚

The letters and words refer to this info right here:

  • "a", "=abbrev" — displays the contents of the .debug_abbrev section.
  • "A", "=addr" — displays the contents of the .debug_addr section.
  • "c", "=cu_index" — displays the contents of the .debug_cu_index and/or .debug_tu_index sections.
  • "f", "=frames" — display the raw contents of a .debug_frame section.
  • "F", "=frames-interp" — display the interpreted contents of a .debug_frame section.
  • "g", "=gdb_index" — displays the contents of the .gdb_index and/or .debug_names sections.
  • "i", "=info" — displays the contents of the .debug_info section. Note: the output from this option can also be restricted by using the --dwarf-depth and --dwarf-start options. 🔥
  • "k", "=links" — displays the contents of the .gnu_debuglink, .gnu_debugaltlink and .debug_sup sections, if any of them are present. It also displays any links to separate dwarf object files (dwo), if they're specified by the DW_AT_GNU_dwo_name or DW_AT_dwo_name attributes in the .debug_info section.
  • "K", "=follow-links" — display the contents of any selected debug sections that are found in linked, separate debug info file(s). This can result in multiple versions of the same debug section being displayed if it exists in more than one file. 😭

On top of that, when displaying DWARF attributes, if a form is found that references the separate debug info file, then the referenced contents also get displayed.

Note — in some distributions this option is enabled by default. It can be disabled via the N debug option. The default can be chosen when configuring the binutils via the --enable-follow-debug-links=yes or --enable-follow-debug-links=no options. If those aren't used, then the default is to enable the following of debug links.
Note — if support for the debuginfod protocol was enabled when the binutils were built, then this option will also include an attempt to contact any debuginfod servers mentioned in the DEBUGINFOD_URLS environment variable. This could take some time to resolve. This behavior can be disabled via the =do-not-use-debuginfod debug option. 💅
  • "N", "=no-follow-links" — disables the following of links to separate debug info files.
  • "D", "=use-debuginfod" — enables contacting debuginfod servers if there's a need to follow debug links. This is the default behavior.
  • "E", "=do-not-use-debuginfod" — disables contacting debuginfod servers when there's a need to follow debug links.
  • "l", "=rawline" — displays the contents of the .debug_line section in a raw format.
  • "L", "=decodedline" — displays the interpreted contents of the .debug_line section.
  • "m", "=macro" — displays the contents of the .debug_macro and/or .debug_macinfo sections.
  • "o", "=loc" — displays the contents of the .debug_loc and/or .debug_loclists sections.
  • "O", "=str-offsets" — displays the contents of the .debug_str_offsets section.
  • "p", "=pubnames" — displays the contents of the .debug_pubnames and/or .debug_gnu_pubnames sections.
  • "r", "=aranges" — displays the contents of the .debug_aranges section.
  • "R", "=Ranges" — displays the contents of the .debug_ranges and/or .debug_rnglists sections.
  • "s", "=str" — displays the contents of the .debug_str, .debug_line_str and/or .debug_str_offsets sections.
  • "t", "=pubtype" — displays the contents of the .debug_pubtypes and/or .debug_gnu_pubtypes sections.
  • "T", "=trace_aranges" — displays the contents of the .trace_aranges section.
  • "u", "=trace_abbrev" — displays the contents of the .trace_abbrev section.
  • "U", "=trace_info" — displays the contents of the .trace_info section.
Note: displaying the contents of .debug_static_funcs, .debug_static_vars and debug_weaknames sections is not currently supported. sad girl hours 🙈
  • --dwarf-depth=n — limit the dump of the ".debug_info" section to n children. This is only useful with --debug-dump=info. The default is to print all DIEs; and 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 won't 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 --debug-dump=info.

If specified, this option suppresses printing of any header information and all DIEs before the DIE numbered n. Only siblings and children of the specified DIE get printed.

This one can be used in conjunction with --dwarf-depth. 🦋

  • --dwarf-check — enable additional checks for consistency of Dwarf information. be safe out here bestie.
  • --ctf[=section] — display the contents of the specified CTF section. CTF sections themselves contain many subsections, and all of them get displayed in order. ✨

By default, it displays the name of the section named .ctf, which is the name emitted by ld.

  • --ctf-parent=member — so when a CTF section has ambiguously-defined types, it's actually an archive of a bunch of CTF dictionaries, and they all inherit from one dictionary that holds the unambiguous types. That parent member is named .ctf by default, same as the section it lives in — but plot twist, the name can be changed at link time with the ctf_link_set_memb_name_changer function. So if you're staring at a CTF archive some linker made with the name changer doing its thing, --ctf-parent is how you tell objdump the name of the parent. bestie, it's giving "i know the parent's new name, here it is". 💅
  • --ctf-parent-section=section — this one lets you pick a completely different section for the CTF parent dictionary (the unambiguous-types one) than the one holding the child dictionaries (the ambiguous remainder). Note: the linker does not emit ELF objects structured like this — but some third-party linkers might. Also super handy when you're inspecting CTF written out as multiple raw files so you can compose them with objcopy, which can drop them into different ELF sections but not into different members of a single CTF dict. 🫶
  • --sframe[=section] — show the contents of the specified SFrame section. By default it displays the name of the section called .sframe, which is the name ld emits. ✨
  • -G, --stabs — display the full contents of any sections requested, and show the contents of the .stab, .stab.index and .stab.excl sections from an ELF file. Heads up though: this is only useful on systems (like Solaris 2.0) where ".stab" debugging symbol-table entries live in an ELF section. In most other file formats, debugging symbol-table entries are interleaved with linkage symbols and you'll see them in the --syms output instead. 👑
  • --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 also affects the output of the -d, -r and -s options. (yes, it's the matching pair to the one above, they're a duo 💖)
  • -t, --syms — print the symbol table entries of the file. This is similar to what nm gives you, though the display format is different. The output format depends on the file format you're dumping, 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 is 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 auxiliary 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 called its address). The next field is actually a set of characters and spaces showing which flag bits are set on the symbol — they're described below. Next comes the section the symbol is associated with, 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 symbols 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 nor global for a whole bunch of reasons, e.g. because it's used for debugging — but ngl, if it's ever both local and global, that's probably an indication of a bug. 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), a dynamic symbol (D), or a normal symbol (a space).
  • "F" "f" "O" — the symbol is the name of a function (F), a file (f), 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, like certain types of shared libraries. It's similar to what nm gives you when you pass it the -D (--dynamic) option.

The output format is similar to what --syms produces, except an extra field is inserted before the symbol's name, giving the version information associated with the symbol. If the version is the default version used when resolving unversioned references to the symbol, it's displayed as is — otherwise it gets put into parentheses. ✨

  • --special-syms — when displaying symbols, include the ones the target considers special in some way, which normally wouldn't be of interest to the user. 👑
  • -U [d|i|l|e|x|h], --unicode=[default|invalid|locale|escape|hex|highlight] — controls how UTF-8 encoded multibyte characters get displayed in strings. The default (--unicode=default) is to give them no special treatment. The --unicode=locale option displays the sequence in the current locale, which may or may not support them. The options --unicode=hex and --unicode=invalid display them as hex byte sequences enclosed by either angle brackets or curly braces.

The --unicode=escape option displays them as escape sequences (\uxxxx), and the --unicode=highlight option displays them as escape sequences highlighted in red (if the output device supports it). The colouring is intended to draw attention to the presence of unicode sequences where they might not be expected. 🌈

  • -V, --version — print the version number of objdump and exit. iconic. 💅
  • -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. the "give me everything" button fr fr 🎀
  • -w, --wide — format some lines for output devices that have more than 80 columns. Also, do not truncate symbol names when they're displayed. 🫶
  • -z, --disassemble-zeroes — normally the disassembly output skips blocks of zeroes. This option directs the disassembler to disassemble those blocks, just like any other data.
  • -Z, --decompress — the -Z option is meant to be used in conunction with the -s option. It instructs objdump to decompress any compressed sections before displaying their contents. (and yes, "conunction" is exactly what the original says, we keep the typos, we don't touch the lore 💖)
  • @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. go read those next bestie, the lore runs deep 📚

Copyright (c) 1991-2025 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".

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