/mkcross

Easily create a cross compile toolchain using the host clang

Primary LanguagePython

mkcross

mkcross is a super fast python toolkit to make linux and windows (mingw) toolchains in seconds

Comparision (12900kf, aarch64-linux-musl)

Program Supported targets Time to compile aarch64-linux-musl (including downloads) program itself can run without being configured Programmed in Multi target in one command
mkcross Musl/Linux, Mingw/Windows, Picolibc/Baremetal 30s (90s) ✅ Python, C++ ✅
musl-cross-make Musl/Linux 176s (197s) ✅ Shell, Makefile ❌
crosstool-ng uClibc/Linux GNU/Linux Newlib/Baremetal N/A - no musl support ❌ Makefile ❌

Features

  • Extremely fast.
  • Portable sysroots - you can mv the sysroot anywhere you want and it will still work.
  • Supports Windows, Linux, Baremetal, and - experimentally - WasiX.
  • Supports every architecture LLVM supports.
  • No need to compile a whole compiler for your target
    • Much faster to compile just compiler-rt, libc, libc++ than binutils, gcc and libc.
    • No need to fiddle with binutils' and gcc's autoconf
  • Sysroots can be used on any machine with clang and LLVM tools installed.

How to use

Clang

Simply run clang like this:

clang --config-system-dir=[Path to sysroot]/etc/mkcross/clang

CMake

Run cmake with -DCMAKE_TOOLCHAIN_FILE=[Path to sysroot]/etc/mkcross/toolchain.cmake

How to make sysroot?

run mkcross --target=<triple>

How?

  • LLVM is a cross compiler by nature. If you feed it the correct libraries, it will happily output what you want. This program will download and/or compile the needed libraries. There is no need to download/compile a whole compiler.

Notice

  • wasix support is currently highly experimental
  • baremetal c++ is WIP and may not work on every architecture.

What's next?

  • WasiX support (EXPERIMENTAL)
  • Windows target support
    • MingW
    • Proprietary (Visual Studio)
  • FreeBSD
    • Prebuilt (base.tar)
    • From sources (src.tar)
    • Mix (one of above + upstream LLVM)
  • MacOS target support
    • Some free software way
    • Proprietary (XCode.xip)
  • Linux
    • musl
    • uclibc
    • glibc (cannot yet be built with clang)
  • Bare metal (EXPERIMENTAL)
  • Common libraries - zlib, curl, openssl
  • More architectures in compiler RT
    • Upstream to LLVM
  • Parallel download and source extraction
  • Parallel target generation
    • Will require copying autoconf/symlinking source files.
  • Query github api for source tarball size when download.
  • Better config and yaml config for target
  • Github actions to compile common targets
  • Meson support (depends on this)

Notes

  • mingw targets are not abi compatible with gcc mingw! They are however compatible with MSVC, including C++, thanks to the efforts of Google.

Troubleshooting tips

I get errors when compiling c++ statically!

You need to link with more c++ libs: -lc++abi and potentially -lunwind

relocation R_RISCV_HI20 out of range: 524288 is not in [-524288, 524287];

You cant compile with LTO. I need to investigate this further. If you care about the details, see this blog post

strtoll_l strtoull_l strtof_l strtod_l strtold_l etc. are undefined on picolibc:

Add -D_GNU_SOURCE to your defines.