Tier: 3

Windows targets similar to *-pc-windows-gnu but using UCRT as the runtime and various LLVM tools/libraries instead of GCC/Binutils.

Target triples available so far:

  • aarch64-pc-windows-gnullvm
  • i686-pc-windows-gnullvm
  • x86_64-pc-windows-gnullvm

Target maintainers


The easiest way to obtain these targets is cross-compilation but native build from x86_64-pc-windows-gnu is possible with few hacks which I don't recommend. Std support is expected to be on pair with *-pc-windows-gnu.

Binaries for this target should be at least on pair with *-pc-windows-gnu in terms of requirements and functionality.

Those targets follow Windows calling convention for extern "C".

Like with any other Windows target created binaries are in PE format.

Building the target

For cross-compilation I recommend using llvm-mingw toolchain, one change that seems necessary beside configuring cross compilers is disabling experimental m86k target. Otherwise LLVM build fails with multiple definition ... errors. Native bootstrapping builds require rather fragile hacks until host artifacts are available so I won't describe them here.

Building Rust programs

Rust does not yet ship pre-compiled artifacts for this target. To compile for this target, you will either need to build Rust with the target enabled (see "Building the target" above), or build your own copy of core by using build-std or similar.


Created binaries work fine on Windows or Wine using native hardware. Testing AArch64 on x86_64 is problematic though and requires spending some time with QEMU. Once these targets bootstrap themselves on native hardware they should pass Rust testsuite.

Cross-compilation toolchains and C code

Compatible C code can be built with Clang's aarch64-pc-windows-gnu, i686-pc-windows-gnullvm and x86_64-pc-windows-gnu targets as long as LLVM based C toolchains are used. Those include: