LLVM-CXXMAP(1)

💅 LLVM-CXXMAP 💅

okay bestie, welcome to llvm-cxxmap — the mangled name remapping tool from your friends over in LLVM. it lives in section 1 of the manual, and honestly? it's giving "niche but iconic." 🎀

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✨ NAME ✨

llvm-cxxmap — mangled name remapping tool 🦋

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🌸 SYNOPSIS 🌸

llvm-cxxmap [options] symbol-file-1 symbol-file-2

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💖 DESCRIPTION 💖

so here's the vibe: llvm-cxxmap does fuzzy matching of C++ mangled names, and it figures out what matches what based on a file that tells it which name components should be considered equivalent. lowkey genius. 🧠✨

the symbol files should each contain a list of C++ mangled names, one per line — like, respectfully, one name per line, that's the rule. blank lines and lines starting with # are ignored (yes queen, comment your stuff).

the output is a list of pairs of equivalent symbols, one per line, of the form:

<symbol-1> <symbol-2>

where <symbol-1> is a symbol from symbol-file-1 and <symbol-2> is a symbol from symbol-file-2. and bestie, listen — mappings for which the two symbols are identical are omitted. if it's the same symbol, we don't talk about it. periodt. 💅

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🔥 OPTIONS 🔥

• -remapping-file=file, -r=file — point this at a file containing the list of equivalence rules that get used to decide whether two symbols are equivalent. it's required, no cap. see the remapping file section below for the tea. 🫖
• -output=file, -o=file — where the list of matched names gets written. if you don't specify it, it goes to stdout. no biggie.
• -Wambiguous — produce a warning if there are multiple equivalent (but distinct) symbols in symbol-file-2. multiple matches? messy. you get warned. 😭
• -Wincomplete — produce a warning if symbol-file-1 contains a symbol that has no equivalent symbol in symbol-file-2. like, hello? where's their match? 👀

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🌈 REMAPPING FILE 🌈

the remapping file is a text file containing lines of the form:

fragmentkind fragment1 fragment2

where fragmentkind is one of name, type, or encoding — indicating whether the following mangled name fragments are names (<http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.name>), types (<http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.type>), or encodings (<http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.encoding>), respectively. blank lines and lines starting with # are ignored here too. consistency slay. ✨

unmangled C names can be expressed as an encoding that is a (length-prefixed) source-name (<http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.source-name>):

# C function "void foo_bar()" is remapped to C++ function "void foo::bar()".
encoding 7foo_bar _Z3foo3barv

for convenience, built-in substitutions such as St and Ss are accepted as names — even though they technically are not names. we don't gatekeep here. 🙈

for example, to specify that absl::string_view and std::string_view should be treated as equivalent, the following remapping file could be used:

# absl::string_view is considered equivalent to std::string_view
type N4absl11string_viewE St17basic_string_viewIcSt11char_traitsIcEE

# std:: might be std::__1:: in libc++ or std::__cxx11:: in libstdc++
name St St3__1
name St St7__cxx11

⭐ Note ⭐

symbol remapping is currently only supported for C++ mangled names following the Itanium C++ ABI mangling scheme. this covers all C++ targets supported by Clang other than Windows targets. so if you're on Windows, bestie… this is not your era. 💀

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👑 Author 👑

maintained by the LLVM Team (<https://llvm.org/>). absolute icons. 🫶

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🎀 Copyright 🎀

2003-2026, LLVM Project

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and that's the whole page!! no notes, ate and left no crumbs 💜 — this one's from LLVM, version 15, dated 2026-09-09, so if you ever need to cite it in a group chat, now you know. bye bestie, go remap some mangled names 🦋🌸🍓