nodejs/node · error · ValueError

Unsupported libffi target {os_name}/{target_arch}.

Error message

Unsupported libffi target {os_name}/{target_arch}.

What it means

libffi's generate-headers.py maps an (os_name, target_arch) pair to a preprocessor define and a source subdirectory (e.g. X86_64/x86_64). get_target() has explicit branches for the supported platforms/arches; any combination not listed falls through to this ValueError, signalling that no ffitarget header template exists for that target.

Source

Thrown at deps/libffi/generate-headers.py:64

    if target_arch == 'loong64':
        return ('LOONGARCH64', 'loongarch')

    if target_arch in ('mips', 'mipsel', 'mips64el'):
        if os_name in ('freebsd', 'linux', 'openbsd'):
            return ('MIPS', 'mips')

    if target_arch == 'ppc64':
        if os_name == 'aix':
            return ('POWERPC_AIX', 'powerpc')
        if os_name == 'mac':
            return ('POWERPC_DARWIN', 'powerpc')
        if os_name in ('freebsd', 'openbsd'):
            return ('POWERPC_FREEBSD', 'powerpc')
        if os_name == 'linux':
            return ('POWERPC', 'powerpc')

    raise ValueError(f'Unsupported libffi target {os_name}/{target_arch}.')


def has_long_double(os_name, target_arch):
    target_arch = normalize_arch(target_arch)

    if os_name == 'win':
        return '0'

    if os_name == 'mac' and target_arch == 'arm64':
        return '0'

    if target_arch == 'arm':
        return '0'

    return '1'


def uses_exec_trampoline_table(os_name, target_arch):

View on GitHub (pinned to 1b2de5e052)

Solutions

1. Confirm the (os, arch) pair is one libffi supports in get_target(); pick the closest supported target.
2. If you must build for an unsupported arch, vendor the missing ffitarget.h template and extend get_target().
3. Check that --target-arch / TARGET_ARCH env uses a recognized alias (x64 not 'amd64-intel').

Example fix

# before
python generate-headers.py --output-dir out --target-arch riscv64 --os linux
# after
python generate-headers.py --output-dir out --target-arch x86_64 --os linux

SUPPORTED = {('linux','x86_64'),('linux','arm64'),('mac','arm64'),('win','x86_64')}
assert (os_name, target_arch) in SUPPORTED, f'unsupported libffi target {os_name}/{target_arch}'

def is_supported_libffi_target(os_name, target_arch):
    pairs = {('linux','x86'),('linux','x86_64'),('linux','arm'),('linux','arm64'),
             ('mac','x86_64'),('mac','arm64'),('win','x86'),('win','x86_64'),
             ('freebsd','x86_64'),('aix','ppc64')}
    return (os_name, target_arch) in pairs

When it happens

Trigger: Raised at the end of get_target() when target_arch is not one of x86/x86_64/arm/arm64/mips/mipsel/... or when a known arch is paired with an unsupported os_name (e.g. ppc64 only handled for aix/mac/freebsd/openbsd/linux).

Common situations: Cross-compiling for an architecture libffi's bundled headers don't ship (riscv, s390x, loongarch); exotic os/arch matrix cells in CI; a typo in --target-arch or an alias the normalizer doesn't recognize.

Related errors

• Unsupported host platform {sys.platform!r}
• Unable to determine target architecture for libffi headers
• Missing libffi target header: {ffitarget_src}
• Unable to locate a compiler for preprocessing assembly
• Unable to locate armasm64.exe

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/3df01fc08a0e4a42. Report an issue: GitHub.