`scripts/rust_is_available.sh` calls `bindgen` with a special
header in order to check whether the `libclang` version in use
is suitable.
However, the invocation itself may fail if, for instance, `bindgen`
cannot locate `libclang`. This is fine for Kconfig (since the
script will still fail and therefore disable Rust as it should),
but it is pretty confusing for users of the `rustavailable` target
given the error will be unrelated:
./scripts/rust_is_available.sh: 21: arithmetic expression: expecting primary: "100000 * + 100 * + "
make: *** [Makefile:1816: rustavailable] Error 2
Instead, run the `bindgen` invocation independently in a previous
step, saving its output and return code. If it fails, then show
the user a proper error message. Otherwise, continue as usual
with the saved output.
Since the previous patch we show a reference to the docs, and
the docs now explain how `bindgen` looks for `libclang`,
thus the error message can leverage the documentation, avoiding
duplication here (and making users aware of the setup guide in
the documentation).
Reported-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Reported-by: fvalenduc (@fvalenduc)
Reported-by: Alexandru Radovici <msg4alex@xxxxxxxxx>
Link: https://lore.kernel.org/rust-for-linux/CAKwvOdm5JT4wbdQQYuW+RT07rCi6whGBM2iUAyg8A1CmLXG6Nw@xxxxxxxxxxxxxx/
Link: https://github.com/Rust-for-Linux/linux/issues/934
Link: https://github.com/Rust-for-Linux/linux/pull/921
Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
---
scripts/rust_is_available.sh | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/scripts/rust_is_available.sh b/scripts/rust_is_available.sh
index c907cf881c2c..cd87729ca3bf 100755
--- a/scripts/rust_is_available.sh
+++ b/scripts/rust_is_available.sh
@@ -108,8 +108,29 @@ if [ "$rust_bindings_generator_cversion" -gt "$rust_bindings_generator_min_cvers
fi
# Check that the `libclang` used by the Rust bindings generator is suitable.
+#
+# In order to do that, first invoke `bindgen` to get the `libclang` version
+# found by `bindgen`. This step may already fail if, for instance, `libclang`
+# is not found, thus inform the user in such a case.
+set +e
+bindgen_libclang_output=$(LC_ALL=C "$BINDGEN" $(dirname $0)/rust_is_available_bindgen_libclang.h 2>&1 >/dev/null)
+bindgen_libclang_code=$?
+set -e
+if [ $bindgen_libclang_code -ne 0 ]; then
+ echo >&2 "***"
+ echo >&2 "*** Running '$BINDGEN' to check the libclang version (used by the Rust"
+ echo >&2 "*** bindings generator) failed with code $bindgen_libclang_code. This may be caused by"
+ echo >&2 "*** a failure to locate libclang. See output and docs below for details:"
+ echo >&2 "***"
+ echo >&2 "$bindgen_libclang_output"
+ echo >&2 "***"
+ exit 1
+fi
+
+# `bindgen` returned successfully, thus use the output to check that the version
+# of the `libclang` found by the Rust bindings generator is suitable.
bindgen_libclang_version=$( \
- LC_ALL=C "$BINDGEN" $(dirname $0)/rust_is_available_bindgen_libclang.h 2>&1 >/dev/null \
+ echo "$bindgen_libclang_output" \
| grep -F 'clang version ' \
| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
| head -n 1 \
--
2.39.0
