LLVM-NM(1)

📦
version 11.1.0 · 2 versions
, in fedora 43, fedora 44

💖 llvm-nm — the LLVM manual page, bestie edition 💖

okay so you opened the llvm-nm page from the LLVM manual set (yes, the one literally titled LLVM-NM(1)) and you want the tea ☕. Buckle up, because this little utility is lowkey iconic and I'm about to tell you everything about it. No skips, no "you don't need this part" — we're doing the whole thing. 🫶

✨ NAME ✨

llvm-nm — list LLVM bitcode and object file's symbol table

🌸 SYNOPSIS 🌸

llvm-nm [options] [filenames...]

🦋 DESCRIPTION 🦋

The llvm-nm utility lists the names of symbols from LLVM bitcode files, object files, and archives. Every symbol shows up next to some simple info about where it came from. If you don't give it a filename, it just uses a.out as the input, no questions asked. And if you use - as a filename, llvm-nm will read a file from its standard input stream. stdin queen behavior honestly. 💅

llvm-nm's default output format is the traditional BSD nm output format. Each record it prints is: an (optional) 8-digit hexadecimal address, then a type code character, then a name — one record per line, fields separated by spaces. And when the address is omitted? It gets replaced by 8 spaces. Not zero spaces, bestie, eight. Respect the craft. ✨

Now here are the supported type code characters. Important detail: where both lower and upper-case characters are listed for the same meaning, a lower-case character represents a local symbol, whilst an upper-case character represents a global (external) symbol. iykyk.

  • a, A — Absolute symbol.
  • b, B — Uninitialized data (bss) object.
  • C — Common symbol. Multiple definitions link together into one definition.
  • d, D — Writable data object.
  • i, I — COFF: .idata symbol or symbol in a section with IMAGE_SCN_LNK_INFO set.
  • n — ELF: local symbol from non-alloc section. COFF: debug symbol.
  • N — ELF: debug section symbol, or global symbol from non-alloc section.
  • s, S — COFF: section symbol. Mach-O: absolute symbol or symbol from a section other than __TEXT_EXEC __text, __TEXT __text, __DATA __data, or __DATA __bss.
  • r, R — Read-only data object.
  • t, T — Code (text) object.
  • u — ELF: GNU unique symbol.
  • U — Named object is undefined in this file.
  • v — ELF: Undefined weak object. It is not a link failure if the object is not defined.
  • V — ELF: Defined weak object symbol. This definition will only be used if no regular definitions exist in a link. If multiple weak definitions and no regular definitions exist, one of the weak definitions will be used.
  • w — Undefined weak symbol other than an ELF object symbol. It is not a link failure if the symbol is not defined.
  • W — Defined weak symbol other than an ELF object symbol. This definition will only be used if no regular definitions exist in a link. If multiple weak definitions and no regular definitions exist, one of the weak definitions will be used.
  • - — Mach-O: N_STAB symbol.
  • ? — Something unrecognizable. (me trying to read my own notes tbh 😭)
Because LLVM bitcode files typically contain objects that are not considered to have addresses until they are linked into an executable image or dynamically compiled "just-in-time", llvm-nm does not print an address for any symbol in an LLVM bitcode file — even symbols which are defined in the bitcode file. No address for you, bestie. Not even the defined ones. 🎀

👑 OPTIONS 👑

  • -B — Use BSD output format. Alias for --format=bsd.
  • --debug-syms, -a — Show all symbols, even those usually suppressed. (nothing stays hidden from her 💅)
  • --defined-only, -U — Print only symbols defined in this file.
  • --demangle, -C — Demangle symbol names. un-mangling the chaos ✨
  • --dynamic, -D — Display dynamic symbols instead of normal symbols.
  • --extern-only, -g — Print only symbols whose definitions are external; that is, accessible from other files.
  • --format=<format>, -f — Select an output format; format may be sysv, posix, darwin, or bsd. The default is bsd.
  • --help, -h — Print a summary of command-line options and their meanings.
  • --help-list — Print an uncategorized summary of command-line options and their meanings.
  • --just-symbol-name, -j — Print just the symbol names. no extras, minimal, clean 🧚
  • -m — Use Darwin format. Alias for --format=darwin.
  • --no-demangle — Don't demangle symbol names. This is the default.
  • --no-llvm-bc — Disable the LLVM bitcode reader.
  • --no-sort, -p — Show symbols in the order encountered.
  • --no-weak, -W — Don't print weak symbols.
  • --numeric-sort, -n, -v — Sort symbols by address.
  • --portability, -P — Use POSIX.2 output format. Alias for --format=posix.
  • --print-armap, -M — Print the archive symbol table, in addition to the symbols.
  • --print-file-name, -A, -o — Precede each symbol with the file it came from.
  • --print-size, -S — Show symbol size as well as address (not applicable for Mach-O).
  • --radix=<RADIX>, -t — Specify the radix of the symbol address(es). Values accepted are d (decimal), x (hexadecimal) and o (octal).
  • --reverse-sort, -r — Sort symbols in reverse order.
  • --size-sort — Sort symbols by size.
  • --special-syms — Do not filter special symbols from the output.
  • --undefined-only, -u — Print only undefined symbols.
  • --version — Display the version of the llvm-nm executable. Does not stack with other commands. (one job, does it gorgeously 🔥)
  • --without-aliases — Exclude aliases from the output.
  • @<FILE> — Read command-line options from response file <FILE>.

🍓 MACH-O SPECIFIC OPTIONS 🍓

these ones are for the Apple girlies 🍎✨

  • --add-dyldinfo — Add symbols from the dyldinfo, if they are not already in the symbol table. This is the default.
  • --add-inlinedinfo — Add symbols from the inlined libraries, TBD file inputs only.
  • --arch=<arch1[,arch2,...]> — Dump the symbols from the specified architecture(s).
  • --dyldinfo-only — Dump only symbols from the dyldinfo.
  • --no-dyldinfo — Do not add any symbols from the dyldinfo.
  • -s=<segment section> — Dump only symbols from this segment and section name.
  • -x — Print symbol entry in hex.

💀 BUGS 💀

  • llvm-nm does not support the full set of arguments that GNU nm does. yeah. she said what she said. 🙈

🌈 EXIT STATUS 🌈

llvm-nm exits with an exit code of zero. Always slaying, never failing. periodt. 💅

⭐ SEE ALSO ⭐

llvm-ar(1), llvm-objdump(1), llvm-readelf(1), llvm-readobj(1)

go read those too, they're all in the same friend group 🫶

💜 AUTHOR 💜

Maintained by the LLVM Team (https://llvm.org/).

2003-2024, LLVM Project

okay bestie that's the whole page, and as a little sign-off: this was the LLVM manual, release 11, dated 2024-07-18 🎀✨ go list some symbols, you absolute icon 👑

📦 where this page comes from