linux-next/scripts/rust_is_available.sh
Miguel Ojeda 63b27f4a00 rust: start supporting several compiler versions
It is time to start supporting several Rust compiler versions and thus
establish a minimum Rust version.

We may still want to upgrade the minimum sometimes in the beginning since
there may be important features coming into the language that improve
how we write code (e.g. field projections), which may or may not make
sense to support conditionally.

We will start with a window of two stable releases, and widen it over
time. Thus this patch does not move the current minimum (1.78.0), but
instead adds support for the recently released 1.79.0.

This should already be enough for kernel developers in distributions that
provide recent Rust compiler versions routinely, such as Arch Linux,
Debian Unstable (outside the freeze period), Fedora Linux, Gentoo
Linux (especially the testing channel), Nix (unstable) and openSUSE
Tumbleweed. See the documentation patch about it later in this series.

In addition, Rust for Linux is now being built-tested in Rust's pre-merge
CI [1]. That is, every change that is attempting to land into the Rust
compiler is tested against the kernel, and it is merged only if it passes
-- thanks to the Rust project for that!

Thus, with the pre-merge CI in place, both projects hope to avoid
unintentional changes to Rust that break the kernel. This means that,
in general, apart from intentional changes on their side (that we will
need to workaround conditionally on our side), the upcoming Rust compiler
versions should generally work.

For instance, currently, the beta (1.80.0) and nightly (1.81.0) branches
work as well.

Of course, the Rust for Linux CI job in the Rust toolchain may still need
to be temporarily disabled for different reasons, but the intention is
to help bring Rust for Linux into stable Rust.

Link: https://github.com/rust-lang/rust/pull/125209 [1]
Reviewed-by: Finn Behrens <me@kloenk.dev>
Tested-by: Benno Lossin <benno.lossin@proton.me>
Tested-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20240709160615.998336-7-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-07-10 10:28:52 +02:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# Tests whether a suitable Rust toolchain is available.
set -e
min_tool_version=$(dirname $0)/min-tool-version.sh
# Convert the version string x.y.z to a canonical up-to-7-digits form.
#
# Note that this function uses one more digit (compared to other
# instances in other version scripts) to give a bit more space to
# `rustc` since it will reach 1.100.0 in late 2026.
get_canonical_version()
{
IFS=.
set -- $1
echo $((100000 * $1 + 100 * $2 + $3))
}
# Print a reference to the Quick Start guide in the documentation.
print_docs_reference()
{
echo >&2 "***"
echo >&2 "*** Please see Documentation/rust/quick-start.rst for details"
echo >&2 "*** on how to set up the Rust support."
echo >&2 "***"
}
# Print an explanation about the fact that the script is meant to be called from Kbuild.
print_kbuild_explanation()
{
echo >&2 "***"
echo >&2 "*** This script is intended to be called from Kbuild."
echo >&2 "*** Please use the 'rustavailable' target to call it instead."
echo >&2 "*** Otherwise, the results may not be meaningful."
exit 1
}
# If the script fails for any reason, or if there was any warning, then
# print a reference to the documentation on exit.
warning=0
trap 'if [ $? -ne 0 ] || [ $warning -ne 0 ]; then print_docs_reference; fi' EXIT
# Check that the expected environment variables are set.
if [ -z "${RUSTC+x}" ]; then
echo >&2 "***"
echo >&2 "*** Environment variable 'RUSTC' is not set."
print_kbuild_explanation
fi
if [ -z "${BINDGEN+x}" ]; then
echo >&2 "***"
echo >&2 "*** Environment variable 'BINDGEN' is not set."
print_kbuild_explanation
fi
if [ -z "${CC+x}" ]; then
echo >&2 "***"
echo >&2 "*** Environment variable 'CC' is not set."
print_kbuild_explanation
fi
# Check that the Rust compiler exists.
if ! command -v "$RUSTC" >/dev/null; then
echo >&2 "***"
echo >&2 "*** Rust compiler '$RUSTC' could not be found."
echo >&2 "***"
exit 1
fi
# Check that the Rust bindings generator exists.
if ! command -v "$BINDGEN" >/dev/null; then
echo >&2 "***"
echo >&2 "*** Rust bindings generator '$BINDGEN' could not be found."
echo >&2 "***"
exit 1
fi
# Check that the Rust compiler version is suitable.
#
# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
rust_compiler_output=$( \
LC_ALL=C "$RUSTC" --version 2>/dev/null
) || rust_compiler_code=$?
if [ -n "$rust_compiler_code" ]; then
echo >&2 "***"
echo >&2 "*** Running '$RUSTC' to check the Rust compiler version failed with"
echo >&2 "*** code $rust_compiler_code. See output and docs below for details:"
echo >&2 "***"
echo >&2 "$rust_compiler_output"
echo >&2 "***"
exit 1
fi
rust_compiler_version=$( \
echo "$rust_compiler_output" \
| sed -nE '1s:.*rustc ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
)
if [ -z "$rust_compiler_version" ]; then
echo >&2 "***"
echo >&2 "*** Running '$RUSTC' to check the Rust compiler version did not return"
echo >&2 "*** an expected output. See output and docs below for details:"
echo >&2 "***"
echo >&2 "$rust_compiler_output"
echo >&2 "***"
exit 1
fi
rust_compiler_min_version=$($min_tool_version rustc)
rust_compiler_cversion=$(get_canonical_version $rust_compiler_version)
rust_compiler_min_cversion=$(get_canonical_version $rust_compiler_min_version)
if [ "$rust_compiler_cversion" -lt "$rust_compiler_min_cversion" ]; then
echo >&2 "***"
echo >&2 "*** Rust compiler '$RUSTC' is too old."
echo >&2 "*** Your version: $rust_compiler_version"
echo >&2 "*** Minimum version: $rust_compiler_min_version"
echo >&2 "***"
exit 1
fi
# Check that the Rust bindings generator is suitable.
#
# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
rust_bindings_generator_output=$( \
LC_ALL=C "$BINDGEN" --version 2>/dev/null
) || rust_bindings_generator_code=$?
if [ -n "$rust_bindings_generator_code" ]; then
echo >&2 "***"
echo >&2 "*** Running '$BINDGEN' to check the Rust bindings generator version failed with"
echo >&2 "*** code $rust_bindings_generator_code. See output and docs below for details:"
echo >&2 "***"
echo >&2 "$rust_bindings_generator_output"
echo >&2 "***"
exit 1
fi
rust_bindings_generator_version=$( \
echo "$rust_bindings_generator_output" \
| sed -nE '1s:.*bindgen ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
)
if [ -z "$rust_bindings_generator_version" ]; then
echo >&2 "***"
echo >&2 "*** Running '$BINDGEN' to check the bindings generator version did not return"
echo >&2 "*** an expected output. See output and docs below for details:"
echo >&2 "***"
echo >&2 "$rust_bindings_generator_output"
echo >&2 "***"
exit 1
fi
rust_bindings_generator_min_version=$($min_tool_version bindgen)
rust_bindings_generator_cversion=$(get_canonical_version $rust_bindings_generator_version)
rust_bindings_generator_min_cversion=$(get_canonical_version $rust_bindings_generator_min_version)
if [ "$rust_bindings_generator_cversion" -lt "$rust_bindings_generator_min_cversion" ]; then
echo >&2 "***"
echo >&2 "*** Rust bindings generator '$BINDGEN' is too old."
echo >&2 "*** Your version: $rust_bindings_generator_version"
echo >&2 "*** Minimum version: $rust_bindings_generator_min_version"
echo >&2 "***"
exit 1
fi
if [ "$rust_bindings_generator_cversion" -gt "$rust_bindings_generator_min_cversion" ]; then
echo >&2 "***"
echo >&2 "*** Rust bindings generator '$BINDGEN' is too new. This may or may not work."
echo >&2 "*** Your version: $rust_bindings_generator_version"
echo >&2 "*** Expected version: $rust_bindings_generator_min_version"
echo >&2 "***"
warning=1
fi
# Check that the `libclang` used by the Rust bindings generator is suitable.
#
# In order to do that, first invoke `bindgen` to get the `libclang` version
# found by `bindgen`. This step may already fail if, for instance, `libclang`
# is not found, thus inform the user in such a case.
bindgen_libclang_output=$( \
LC_ALL=C "$BINDGEN" $(dirname $0)/rust_is_available_bindgen_libclang.h 2>&1 >/dev/null
) || bindgen_libclang_code=$?
if [ -n "$bindgen_libclang_code" ]; then
echo >&2 "***"
echo >&2 "*** Running '$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.
#
# Unlike other version checks, note that this one does not necessarily appear
# in the first line of the output, thus no `sed` address is provided.
bindgen_libclang_version=$( \
echo "$bindgen_libclang_output" \
| sed -nE 's:.*clang version ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
)
if [ -z "$bindgen_libclang_version" ]; then
echo >&2 "***"
echo >&2 "*** Running '$BINDGEN' to check the libclang version (used by the Rust"
echo >&2 "*** bindings generator) did not return an expected output. See output"
echo >&2 "*** and docs below for details:"
echo >&2 "***"
echo >&2 "$bindgen_libclang_output"
echo >&2 "***"
exit 1
fi
bindgen_libclang_min_version=$($min_tool_version llvm)
bindgen_libclang_cversion=$(get_canonical_version $bindgen_libclang_version)
bindgen_libclang_min_cversion=$(get_canonical_version $bindgen_libclang_min_version)
if [ "$bindgen_libclang_cversion" -lt "$bindgen_libclang_min_cversion" ]; then
echo >&2 "***"
echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN') is too old."
echo >&2 "*** Your version: $bindgen_libclang_version"
echo >&2 "*** Minimum version: $bindgen_libclang_min_version"
echo >&2 "***"
exit 1
fi
# If the C compiler is Clang, then we can also check whether its version
# matches the `libclang` version used by the Rust bindings generator.
#
# In the future, we might be able to perform a full version check, see
# https://github.com/rust-lang/rust-bindgen/issues/2138.
cc_name=$($(dirname $0)/cc-version.sh $CC | cut -f1 -d' ')
if [ "$cc_name" = Clang ]; then
clang_version=$( \
LC_ALL=C $CC --version 2>/dev/null \
| sed -nE '1s:.*version ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
)
if [ "$clang_version" != "$bindgen_libclang_version" ]; then
echo >&2 "***"
echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN')"
echo >&2 "*** version does not match Clang's. This may be a problem."
echo >&2 "*** libclang version: $bindgen_libclang_version"
echo >&2 "*** Clang version: $clang_version"
echo >&2 "***"
warning=1
fi
fi
# Check that the source code for the `core` standard library exists.
#
# `$KRUSTFLAGS` is passed in case the user added `--sysroot`.
rustc_sysroot=$("$RUSTC" $KRUSTFLAGS --print sysroot)
rustc_src=${RUST_LIB_SRC:-"$rustc_sysroot/lib/rustlib/src/rust/library"}
rustc_src_core="$rustc_src/core/src/lib.rs"
if [ ! -e "$rustc_src_core" ]; then
echo >&2 "***"
echo >&2 "*** Source code for the 'core' standard library could not be found"
echo >&2 "*** at '$rustc_src_core'."
echo >&2 "***"
exit 1
fi