1 files changed, 74 insertions, 0 deletions
diff --git a/src/ci/docker/scripts/musl-toolchain.sh b/src/ci/docker/scripts/musl-toolchain.sh
new file mode 100644
index 000000000..e358b8139
--- /dev/null
+++ b/src/ci/docker/scripts/musl-toolchain.sh
@@ -0,0 +1,74 @@
+#!/bin/sh
+# This script runs `musl-cross-make` to prepare C toolchain (Binutils, GCC, musl itself)
+# and builds static libunwind that we distribute for static target.
+#
+# Versions of the toolchain components are configurable in `musl-cross-make/Makefile` and
+# musl unlike GLIBC is forward compatible so upgrading it shouldn't break old distributions.
+# Right now we have: Binutils 2.31.1, GCC 9.2.0, musl 1.1.24.
+
+# ignore-tidy-linelength
+
+set -ex
+
+hide_output() {
+  set +x
+  on_err="
+echo ERROR: An error was encountered with the build.
+cat /tmp/build.log
+exit 1
+"
+  trap "$on_err" ERR
+  bash -c "while true; do sleep 30; echo \$(date) - building ...; done" &
+  PING_LOOP_PID=$!
+  "$@" &> /tmp/build.log
+  trap - ERR
+  kill $PING_LOOP_PID
+  rm /tmp/build.log
+  set -x
+}
+
+ARCH=$1
+TARGET=$ARCH-linux-musl
+
+# Don't depend on the mirrors of sabotage linux that musl-cross-make uses.
+LINUX_HEADERS_SITE=https://ci-mirrors.rust-lang.org/rustc/sabotage-linux-tarballs
+
+OUTPUT=/usr/local
+shift
+
+# Ancient binutils versions don't understand debug symbols produced by more recent tools.
+# Apparently applying `-fPIC` everywhere allows them to link successfully.
+# Enable debug info. If we don't do so, users can't debug into musl code,
+# debuggers can't walk the stack, etc. Fixes #90103.
+export CFLAGS="-fPIC -g1 $CFLAGS"
+
+git clone https://github.com/richfelker/musl-cross-make # -b v0.9.9
+cd musl-cross-make
+# A few commits ahead of v0.9.9 to include the cowpatch fix:
+git checkout a54eb56f33f255dfca60be045f12a5cfaf5a72a9
+
+# Fix the cfi detection script in musl's configure so cfi is generated
+# when debug info is asked for. This patch is derived from
+# https://git.musl-libc.org/cgit/musl/commit/?id=c4d4028dde90562f631edf559fbc42d8ec1b29de.
+# When we upgrade to a version that includes this commit, we can remove the patch.
+mkdir patches/musl-1.1.24
+cp ../musl-patch-configure.diff patches/musl-1.1.24/0001-fix-cfi-detection.diff
+
+hide_output make -j$(nproc) TARGET=$TARGET MUSL_VER=1.1.24 LINUX_HEADERS_SITE=$LINUX_HEADERS_SITE
+hide_output make install TARGET=$TARGET MUSL_VER=1.1.24 LINUX_HEADERS_SITE=$LINUX_HEADERS_SITE OUTPUT=$OUTPUT
+
+cd -
+
+# Install musl library to make binaries executable
+ln -s $OUTPUT/$TARGET/lib/libc.so /lib/ld-musl-$ARCH.so.1
+echo $OUTPUT/$TARGET/lib >> /etc/ld-musl-$ARCH.path
+
+# Now when musl bootstraps itself create proper toolchain symlinks to make build and tests easier
+if [ "$REPLACE_CC" = "1" ]; then
+    for exec in cc gcc; do
+        ln -s $TARGET-gcc /usr/local/bin/$exec
+    done
+    for exec in cpp c++ g++; do
+        ln -s $TARGET-g++ /usr/local/bin/$exec
+    done
+fi