Add build-bpf-gcc action

A prerequisite for running selftests/bpf is a recent version of GCC
compiled for BPF backend.

Signed-off-by: Ihor Solodrai <[email protected]>

build-bpf-gcc/README.md

@@ -0,0 +1,15 @@
+# Build BPF GCC
+
+This action grabs latest GCC 15 source code snapshot from
+https://gcc.gnu.org/pub/gcc/snapshots, as well as most recent
+binutils, and builds GCC for BPF backend and installs it into a
+specified directory.
+
+Resulting artifacts are cached with
+[actions/cache](https://github.com/actions/cache), using snapshot
+names as a key.
+
+## Required inputs
+
+* `install-dir` - Path to the directory where built binaries are going to be installed, or restored from cache.
+

build-bpf-gcc/action.yml

@@ -0,0 +1,28 @@
+name: 'Build BPF GCC'
+description: 'Fetch latest GCC and binutils snapshots, bulid GCC and install into the target directory'
+inputs:
+  install-dir:
+    description: "Path to the GCC installation directory"
+    required: true
+
+runs:
+  using: "composite"
+  steps:
+
+    - name: Determine latest snapshots
+      id: latest-snapshots
+      shell: bash
+      run: ${GITHUB_ACTION_PATH}/latest-snapshots.sh
+
+    - uses: actions/cache@v4
+      id: cache
+      with:
+        path: ${{ inputs.install-dir }}
+        key: BPF-GCC-${{ steps.latest-snapshots.outputs.GCC_BASENAME }}-${{ steps.latest-snapshots.outputs.BINUTILS_BASENAME }}
+
+    - if: steps.cache.outputs.cache-hit != 'true'
+      name: Build BPF GCC
+      shell: bash
+      run: |
+        ${GITHUB_ACTION_PATH}/build-and-install.sh ${{ inputs.install-dir }}
+

build-bpf-gcc/build-and-install.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+set -euo pipefail
+
+source ${GITHUB_ACTION_PATH}/../helpers.sh
+
+INSTALLDIR=$(realpath $1)
+
+if [ -f ${GITHUB_ACTION_PATH}/.env ]; then
+    source ${GITHUB_ACTION_PATH}/.env
+else
+    echo "${GITHUB_ACTION_PATH}/.env is not found, supposed to be produced by latest-snapshots.sh"
+    exit 1
+fi
+
+foldable start download_tarballs "Downloading $BINUTILS_URL and $GCC_URL"
+
+test -f $BINUTILS_TARBALL || wget -q $BINUTILS_URL
+test -f $GCC_TARBALL || wget -q $GCC_URL
+
+foldable end download_tarballs
+
+foldable start build_binutils "Building $BINUTILS_BASENAME"
+
+if [ ! -f  "${INSTALLDIR}/${BINUTILS_BASENAME}.built" ]; then
+  tar xJf $BINUTILS_TARBALL
+  mkdir -p ${BINUTILS_BASENAME}/build-bpf
+  cd ${BINUTILS_BASENAME}/build-bpf
+  ../configure --target=bpf-unknown-none --prefix=$INSTALLDIR
+  make -j$(nproc) && make install
+  touch ${INSTALLDIR}/${BINUTILS_BASENAME}.built
+  cd -
+fi
+
+foldable end build_binutils
+
+foldable start build_gcc "Building $GCC_BASENAME"
+
+if [ ! -f  "${INSTALLDIR}/${GCC_BASENAME}.built" ]; then
+  tar xJf $GCC_TARBALL
+  cd ${GCC_BASENAME}
+  ./contrib/download_prerequisites
+  cd -
+  mkdir -p ${GCC_BASENAME}/build-bpf
+  cd ${GCC_BASENAME}/build-bpf
+  ../configure --target=bpf-unknown-none --prefix=$INSTALLDIR
+  make -j$(nproc) && make install
+  touch ${INSTALLDIR}/${GCC_BASENAME}.built
+  cd -
+fi
+
+foldable end build_gcc
+
+exit 0

build-bpf-gcc/latest-snapshots.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+set -euo pipefail
+
+BINUTILS_TARBALL=`wget https://snapshots.sourceware.org/binutils/trunk/latest/src/sha512.sum -O - -o /dev/null | grep -E 'binutils-[0-9a-f.-]+.tar.xz' | sed -e 's/.*\(binutils-[^<]*\).*/\1/'`
+GCC_TARBALL=`wget https://gcc.gnu.org/pub/gcc/snapshots/LATEST-15 -O - -o /dev/null | grep -E 'gcc-15-[0-9]+.tar.xz' | sed -e 's/.*\(gcc-15-[^<]*\).*/\1/'`
+
+BINUTILS_URL="https://snapshots.sourceware.org/binutils/trunk/latest/src/$BINUTILS_TARBALL"
+GCC_URL="https://gcc.gnu.org/pub/gcc/snapshots/LATEST-15/$GCC_TARBALL"
+
+BINUTILS_BASENAME=$(basename $BINUTILS_TARBALL .tar.xz)
+GCC_BASENAME=$(basename $GCC_TARBALL .tar.xz)
+
+cat > ${GITHUB_ACTION_PATH}/.env <<EOF
+BINUTILS_TARBALL=$BINUTILS_TARBALL
+GCC_TARBALL=$GCC_TARBALL
+BINUTILS_URL=$BINUTILS_URL
+GCC_URL=$GCC_URL
+BINUTILS_BASENAME=$BINUTILS_BASENAME
+GCC_BASENAME=$GCC_BASENAME
+EOF
+
+echo "BINUTILS_BASENAME=${BINUTILS_BASENAME}" >> "$GITHUB_OUTPUT"
+echo "GCC_BASENAME=${GCC_BASENAME}" >> "$GITHUB_OUTPUT"
+
+exit 0

setup-build-env/action.yml

@@ -24,7 +24,7 @@ runs:
       run: |
         echo "::group::Setup"
         sudo apt-get update
-        sudo apt-get install -y cmake flex bison build-essential libssl-dev ncurses-dev xz-utils bc rsync libguestfs-tools qemu-kvm qemu-utils zstd libzstd-dev binutils-dev elfutils libcap-dev libelf-dev libdw-dev python3-docutils
+        sudo apt-get install -y cmake flex bison build-essential libssl-dev ncurses-dev xz-utils bc rsync libguestfs-tools qemu-kvm qemu-utils zstd libzstd-dev binutils-dev elfutils libcap-dev libelf-dev libdw-dev python3-docutils texinfo
         echo "::endgroup::"
     - name: Install clang
       shell: bash