ViNi-Arco / llvm-git

Flexible build script for LLVM in Arch Linux

LLVM build script for Arch Linux

Install dependencies:

pacman -Syu base-devel llvm clang lld vim git \
  ninja cmake libffi libedit ncurses libxml2 \
  ocaml ocaml-ctypes ocaml-findlib python-setuptools \
  python-psutil python-sphinx python-recommonmark

Edit yours /etc/makepkg.conf and set num thread for build in MAKEFLAGS and NINJAFLAGS. It can speed up builds. $(nproc) automatic detect maximum available threads.

MAKEFLAGS="-j$(nproc)"
NINJAFLAGS="-j$(nproc)"

How to use this build script: git clone https://github.com/h0tc0d3/llvm-git.git && cd llvm-git && makepkg -cfi

Build script ask you few questions:

• Build with clang and llvm toolchain? — Y or Enter if yes, or N if not. I recommend build with LLVM and Clang. For this need installed: pacman -Syu base-devel llvm clang lld vim
• Skip build tests? Answer Y or Enter. git version fail some tests and tests needs to skip. It will speed up the assembly.
• Skip build documentation? Y or Enter if yes, or N if not. If you not need llvm documentation then you are can skip. It will speed up the assembly a little.
• Skip build OCaml and Go bindings? Answer Y or Enter if yes, or N if not. Many people don't need them. You can skip it, it will speed up the assembly a little.

Using LLVM and Clang as default system compiler

For build system packages with clang and llvm edit yours /etc/makepkg.conf and remove debug flags -fvar-tracking-assignments, add strings:

export CC=clang
export CXX=clang++
export CC_LD=lld
export CXX_LD=lld
export AR=llvm-ar
export NM=llvm-nm
export STRIP=llvm-strip
export OBJCOPY=llvm-objcopy
export OBJDUMP=llvm-objdump
export READELF=llvm-readelf
export RANLIB=llvm-ranlib
export HOSTCC=clang
export HOSTCXX=clang++
export HOSTAR=llvm-ar

Yours /etc/makepkg.conf can be like this, -march=native can be replaced with your cpu:

CARCH="x86_64"
CHOST="x86_64-pc-linux-gnu"

export CC=clang
export CXX=clang++
export CC_LD=lld
export CXX_LD=lld
export AR=llvm-ar
export NM=llvm-nm
export STRIP=llvm-strip
export OBJCOPY=llvm-objcopy
export OBJDUMP=llvm-objdump
export READELF=llvm-readelf
export RANLIB=llvm-ranlib
export HOSTCC=clang
export HOSTCXX=clang++
export HOSTAR=llvm-ar

CPPFLAGS="-D_FORTIFY_SOURCE=2"
CFLAGS="-fdiagnostics-color=always -pipe -O2 -march=native -fstack-protector-strong --param ssp-buffer-size=4 -fstack-clash-protection"
CXXFLAGS="-fdiagnostics-color=always -pipe -O2 -march=native -fstack-protector-strong --param ssp-buffer-size=4 -fstack-clash-protection"
LDFLAGS="-Wl,-O1 -Wl,-z,now -Wl,-z,relro -Wl,--as-needed -Wl,--no-copy-dt-needed-entries -Wl,--sort-common -Wl,--hash-style=gnu"
RUSTFLAGS="-C opt-level=2"

MAKEFLAGS="-j$(nproc)"
NINJAFLAGS="-j$(nproc)"

DEBUG_CFLAGS="-g"
DEBUG_CXXFLAGS="-g"
DEBUG_RUSTFLAGS="-C debuginfo=2"

For build latest mesa you can use my mesa build script. Edit mesa/mesa.conf file and set dri, gallium, vulkan drivers for build. More info you can find here Mesa OpenGL, mesa-git package, Mesa Documentation. Before build mesa you are also need installed libclc.

You can use my performance important packages which optimized for LLVM Arch Packages.

Build Linux kernel with LLVm and Clang

For build kernel with LLVM read first kernel.org llvm. For use LTO need to set LLVM_IAS=1. I recommend ThinLTO. General architecture-dependent option --> Link Time Optimization (LTO) and then Clang ThinLTO (EXPERIMENTAL). Also, you can enable strong stack protection. Highly recommend! General architecture-dependent options put * against Stack Protector buffer overflow detection и Strong Stack Protector.

You can automate linux kernel build with my script: https://github.com/h0tc0d3/kbuild

https://clang.llvm.org/docs/ThinLTO.html http://blog.llvm.org/2016/06/thinlto-scalable-and-incremental-lto.html