LLVM-CXXMAP(1)

NAME
llvm-cxxmap - Mangled name remapping tool

SYNOPSIS

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

DESCRIPTION

The llvm-cxxmap tool performs fuzzy matching of C++ mangled names, based on a file describing name components that should be considered equivalent.

The symbol files should contain a list of C++ mangled names (one per line). Blank lines and lines starting with # are ignored. 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. Mappings for which the two symbols are identical are omitted.

OPTIONS

-remapping-file=file, -r=file
    Specify a file containing a list of equivalence rules that should be used to determine whether two symbols are equivalent. Required. See REMAPPING FILE.

-output=file, -o=file
    Specify a file to write the list of matched names to. If unspecified, the list will be written to stdout.

-Wambiguous
    Produce a warning if there are multiple equivalent (but distinct) symbols in symbol-file-2.

-Wincomplete
    Produce a warning if symbol-file-1 contains a symbol for which there is no equivalent symbol in symbol-file-2.

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 <name <http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.name>>s, <type <http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.type>>s, or <encoding <http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.encoding>>s, respectively. Blank lines and lines starting with # are ignored.

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 <substitution>s such as St and Ss are accepted as <name>s (even though they technically are not <name>s).

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.

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

Copyright
2003-2026, LLVM Project