ci: build with clang instead of gcc

.github/workflows/build.yml

@@ -2,11 +2,6 @@ name: CI
 
 on:
   workflow_dispatch:
-    inputs:
-      use_qemu:
-        description: 'Use qemu to build linux ppc64le, s390x & riscv64'
-        required: true
-        default: true
   schedule:
     - cron: '0 18 * * 5'  # "At 18:00 on Friday."
   pull_request:
@@ -21,9 +16,6 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
-env:
-  USE_QEMU: ${{ fromJSON(github.event.inputs.use_qemu || 'false') || (github.event_name == 'schedule') || startsWith(github.ref, 'refs/tags/') }}
-
 jobs:
   lint:
     name: Lint
@@ -47,100 +39,78 @@ jobs:
           - os: ubuntu-latest
             arch: "x86_64"
             build: "manylinux_"
-            use_qemu: false
           - os: ubuntu-latest
             arch: "x86_64"
             build: "musllinux_"
-            use_qemu: false
           - os: ubuntu-latest
             arch: "i686"
             build: "manylinux_"
-            use_qemu: false
           - os: ubuntu-latest
             arch: "i686"
             build: "musllinux_"
-            use_qemu: false
           - os: ubuntu-24.04-arm
             arch: "aarch64"
             build: "manylinux_"
-            use_qemu: false
           - os: ubuntu-24.04-arm
             arch: "aarch64"
             build: "musllinux_"
-            use_qemu: false
           - os: ubuntu-latest
             arch: "ppc64le"
             build: "manylinux_"
-            use_qemu: true
           - os: ubuntu-latest
             arch: "ppc64le"
             build: "musllinux_"
-            use_qemu: true
           - os: ubuntu-latest
             arch: "s390x"
             build: "manylinux_"
-            use_qemu: true
           - os: ubuntu-latest
             arch: "s390x"
             build: "musllinux_"
-            use_qemu: true
           - os: ubuntu-latest
             arch: "riscv64"
             build: "manylinux_"
-            use_qemu: true
           - os: ubuntu-latest
             arch: "riscv64"
             build: "musllinux_"
-            use_qemu: true
           - os: ubuntu-24.04-arm
             arch: "armv7l"
             build: "manylinux_"
-            use_qemu: false
           - os: ubuntu-24.04-arm
             arch: "armv7l"
             build: "musllinux_"
-            use_qemu: false
           - os: windows-2022
             arch: "AMD64"
             build: ""
-            use_qemu: false
           - os: windows-11-arm
             arch: "ARM64"
             build: ""
-            use_qemu: false
           - os: windows-2022
             arch: "x86"
             build: ""
-            use_qemu: false
           - os: macos-14
             arch: "universal2"
             build: ""
-            use_qemu: false
 
     steps:
       - uses: actions/checkout@v5
-        if: (!matrix.use_qemu) || fromJSON(env.USE_QEMU)
         with:
           fetch-depth: 0  # required for versioneer to find tags
 
       - uses: astral-sh/setup-uv@v7
-        if: (!matrix.use_qemu) || fromJSON(env.USE_QEMU)
         with:
           enable-cache: false
 
       - name: Set up QEMU
         uses: docker/[email protected]
-        if: matrix.use_qemu && fromJSON(env.USE_QEMU)
+        if: matrix.arch == 'ppc64le' || matrix.arch == 'riscv64' || matrix.arch == 's390x'
 
       - name: Build wheels
         uses: pypa/[email protected]
-        if: (!matrix.use_qemu) || fromJSON(env.USE_QEMU)
         env:
           CIBW_ARCHS: "${{ matrix.arch }}"
           CIBW_BUILD: "cp310-${{ matrix.build }}*"
 
       - uses: actions/upload-artifact@v5
-        if: (!matrix.use_qemu) || fromJSON(env.USE_QEMU)
         with:
           name: cibw-${{ runner.os }}-${{ matrix.build }}${{ matrix.arch }}
           path: ./wheelhouse/*.whl

README.rst

@@ -68,7 +68,7 @@ The following platforms are supported with binary wheels:
   | Linux IBM Z   | | manylinux2014+  s390x   |
   |               | | musllinux_1_2+  s390x   |
   +---------------+---------------------------+
-  | Linux RISC-V  | | manylinux_2_35+ riscv64 |
+  | Linux RISC-V  | | manylinux_2_31+ riscv64 |
   |               | | musllinux_1_2+  riscv64 |
   +---------------+---------------------------+
   | macOS 10.10+  | Intel                     |

pyproject.toml

@@ -105,7 +105,7 @@ manylinux-aarch64-image = "manylinux2014"
 manylinux-ppc64le-image = "manylinux2014"
 manylinux-s390x-image = "manylinux2014"
 manylinux-armv7l-image = "manylinux_2_31"
-manylinux-riscv64-image = "ghcr.io/mayeut/manylinux_2_35:2025.08.02-2"
+manylinux-riscv64-image = "ghcr.io/mayeut/manylinux_2_31:2025.08.23-1"
 musllinux-x86_64-image = "musllinux_1_2"
 musllinux-i686-image = "musllinux_1_2"
 musllinux-aarch64-image = "musllinux_1_2"
@@ -121,9 +121,11 @@ environment = { MACOSX_DEPLOYMENT_TARGET = "10.10" }
 
 [[tool.cibuildwheel.overrides]]
 select = "*-*linux*"
-before-all = "./scripts/manylinux-build-and-install-openssl.sh"
+before-all = "./scripts/install-static-clang.sh && ./scripts/manylinux-build-and-install-openssl.sh"
 inherit.environment = "prepend"
-environment = { PKG_CONFIG_PATH = "/usr/local/ssl/lib/pkgconfig" }
+environment = { CC = "/opt/clang/bin/clang", CXX = "/opt/clang/bin/clang++", LDFLAGS = "-fuse-ld=lld -Wl,--build-id", PKG_CONFIG_PATH = "/usr/local/ssl/lib/pkgconfig" }
+inherit.environment-pass = "prepend"
+environment-pass = ["RUNNER_ARCH"]
 inherit.config-settings = "prepend"
 config-settings."cmake.define.OPENSSL_ROOT_DIR" = "/usr/local/ssl"
 config-settings."cmake.define.OPENSSL_USE_STATIC_LIBS" = "ON"

scripts/install-static-clang.sh

@@ -0,0 +1,102 @@
+#!/bin/bash
+
+# Stop at any error, show all commands
+set -exuo pipefail
+
+TOOLCHAIN_PATH=/opt/clang
+
+# Download static-clang
+DEFAULT_ARCH="$(uname -m)"
+if [ "${STATIC_CLANG_ARCH:-}" == "" ]; then
+	STATIC_CLANG_ARCH="${RUNNER_ARCH:-${DEFAULT_ARCH}}"
+fi
+case "${STATIC_CLANG_ARCH}" in
+	ARM64|aarch64|arm64|arm64/*) GO_ARCH=arm64;;
+	ARM|armv7l|armv8l|arm|arm/v7) GO_ARCH=arm;;  # assume arm/v7 for arm
+	X64|x86_64|amd64|amd64/*) GO_ARCH=amd64;;
+	X86|i686|386) GO_ARCH=386;;
+	ppc64le) GO_ARCH=ppc64le;;
+	riscv64) GO_ARCH=riscv64;;
+	s390x) GO_ARCH=s390x;;
+	*) echo "No static-clang toolchain for ${CLANG_ARCH}">2; exit 1;;
+esac
+STATIC_CLANG_VERSION=21.1.5.0
+STATIC_CLANG_FILENAME="static-clang-linux-${GO_ARCH}.tar.xz"
+STATIC_CLANG_URL="https://github.com/mayeut/static-clang-images/releases/download/v${STATIC_CLANG_VERSION}/${STATIC_CLANG_FILENAME}"
+pushd /tmp
+cat<<'EOF' | grep "${STATIC_CLANG_FILENAME}" > "${STATIC_CLANG_FILENAME}.sha256"
+7af47b1c41dd1e76e08d33f13f7fe33eb43849040f69499516f3f01708b12ae0  static-clang-linux-386.tar.xz
+395463d070de084f249bf08d3a8a88a42f19bce24cad37b45c78d48a62a73bdc  static-clang-linux-amd64.tar.xz
+294839579cf4d2fb5343b6ee1e1613f126c765664e253f2109725d5f49db6aa3  static-clang-linux-arm.tar.xz
+7476d44530b560c5bdc1b085c8651810c2fece201410d831c47b2d3b8101c1b2  static-clang-linux-arm64.tar.xz
+dcdb642827b5da8570b312c1a877bdf4a2b0f7e3004394a3b216134c3178f346  static-clang-linux-loong64.tar.xz
+6b247ae1ce6d095375cd4f37a0484f0c91f8457e3c3f3bb7f9c125a414b19bed  static-clang-linux-ppc64le.tar.xz
+fb0cce0e1fecceb6d3eb2e095297731107c0803605815b37a5cbcec270700088  static-clang-linux-riscv64.tar.xz
+18cbfc7471a40a091b02b2999303dfa3f87368dd01e65d0d3ca7b216826ac84f  static-clang-linux-s390x.tar.xz
+EOF
+curl -fsSLO "${STATIC_CLANG_URL}"
+sha256sum -c "${STATIC_CLANG_FILENAME}.sha256"
+tar -C /opt -xf "${STATIC_CLANG_FILENAME}"
+popd
+
+# configure target triple
+case "${AUDITWHEEL_POLICY}-${AUDITWHEEL_ARCH}" in
+	manylinux*-armv7l) TARGET_TRIPLE=armv7-unknown-linux-gnueabihf;;
+	musllinux*-armv7l) TARGET_TRIPLE=armv7-alpine-linux-musleabihf;;
+	manylinux*-ppc64le) TARGET_TRIPLE=powerpc64le-unknown-linux-gnu;;
+	musllinux*-ppc64le) TARGET_TRIPLE=powerpc64le-alpine-linux-musl;;
+	manylinux*-*) TARGET_TRIPLE=${AUDITWHEEL_ARCH}-unknown-linux-gnu;;
+	musllinux*-*) TARGET_TRIPLE=${AUDITWHEEL_ARCH}-alpine-linux-musl;;
+esac
+case "${AUDITWHEEL_ARCH}" in
+	riscv64) M_ARCH="-march=rv64gc";;
+	x86_64) M_ARCH="-march=x86-64";;
+	armv7l) M_ARCH="-march=armv7a";;
+	i686) M_ARCH="-march=i686";;
+esac
+GCC_TRIPLE=$(gcc -dumpmachine)
+
+if [ "${AUDITWHEEL_ARCH}" == "riscv64" ]; then
+	# the LDFLAGS from pyproject.toml seems not to be taken into account when building CMake (no problem with OpenSSL)
+	# FAILED: [code=1] Source/kwsys/cmsysTestProcess
+	#  : && /opt/clang/bin/clang -D_POSIX_C_SOURCE=199506L -D_POSIX_SOURCE=1 -D_SVID_SOURCE=1 -D_BSD_SOURCE=1 -O3 -DNDEBUG  -lstdc++ -lgcc -lrt Source/kwsys/CMakeFiles/cmsysTestProcess.dir/testProcess.c.o  -o Source/kwsys/cmsysTestProcess  Source/kwsys/libcmsys_c.a && :
+	#  /usr/bin/riscv64-linux-gnu-ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0_zifencei2p0_zmmul1p0_zaamo1p0_zalrsc1p0: unsupported ISA subset `z'
+	#  /usr/bin/riscv64-linux-gnu-ld: failed to merge target specific data of file Source/kwsys/libcmsys_c.a(ProcessUNIX.c.o)
+	#  /usr/bin/riscv64-linux-gnu-ld: -march=rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0_zifencei2p0_zmmul1p0_zaamo1p0_zalrsc1p0: unsupported ISA subset `z'
+	#  /usr/bin/riscv64-linux-gnu-ld: failed to merge target specific data of file Source/kwsys/libcmsys_c.a(System.c.o)
+	#  clang: error: linker command failed with exit code 1 (use -v to see invocation)
+	IMPLICIT_LLD="-fuse-ld=lld"
+fi
+
+cat<<EOF >"${TOOLCHAIN_PATH}/bin/${AUDITWHEEL_PLAT}.cfg"
+	-target ${TARGET_TRIPLE}
+	${M_ARCH:-}
+	--gcc-toolchain=${DEVTOOLSET_ROOTPATH:-}/usr
+	--gcc-triple=${GCC_TRIPLE}
+	${IMPLICIT_LLD:-}
+EOF
+
+cat<<EOF >"${TOOLCHAIN_PATH}/bin/clang.cfg"
+	@${AUDITWHEEL_PLAT}.cfg
+EOF
+
+cat<<EOF >"${TOOLCHAIN_PATH}/bin/clang++.cfg"
+	@${AUDITWHEEL_PLAT}.cfg
+EOF
+
+cat<<EOF >"${TOOLCHAIN_PATH}/bin/clang-cpp.cfg"
+	@${AUDITWHEEL_PLAT}.cfg
+EOF
+
+# override entrypoint to add the toolchain to PATH
+mv /usr/local/bin/manylinux-entrypoint /usr/local/bin/manylinux-entrypoint-org
+cat<<EOF >/usr/local/bin/manylinux-entrypoint
+#!/bin/bash
+
+set -eu
+
+export PATH="${TOOLCHAIN_PATH}/bin:\${PATH}"
+exec /usr/local/bin/manylinux-entrypoint-org "\$@"
+EOF
+
+chmod +x /usr/local/bin/manylinux-entrypoint

scripts/manylinux-build-and-install-openssl.sh

@@ -46,6 +46,12 @@ check_sha256sum ${OPENSSL_ROOT}.tar.gz ${OPENSSL_HASH}
 tar -xzf ${OPENSSL_ROOT}.tar.gz
 rm -rf ${OPENSSL_ROOT}.tar.gz
 
+LIBATOMIC=
+if [ "${AUDITWHEEL_ARCH}" == "i686" ]; then
+	LIBATOMIC=-latomic
+fi
+export LDLIBS="${LIBATOMIC}"
+
 # Configure
 pushd ${OPENSSL_ROOT}
 ./config no-shared no-tests -fPIC --prefix=/usr/local/ssl --openssldir=/usr/local/ssl > /dev/null