kbuild: rust: add CONFIG_RUSTC_VERSION

Now that we support several Rust versions, introduce
`CONFIG_RUSTC_VERSION` so that it can be used in Kconfig to enable and
disable configuration options based on the `rustc` version.

The approach taken resembles `pahole`'s -- see commit 613fe16923
("kbuild: Add CONFIG_PAHOLE_VERSION"), i.e. a simple version parsing
without trying to identify several kinds of compilers, since so far
there is only one (`rustc`).

However, unlike `pahole`'s, we also print a zero if executing failed for
any reason, rather than checking if the command is found and executable
(which still leaves things like a file that exists and is executable,
but e.g. is built for another platform [1]). An equivalent approach to
the one here was also submitted for `pahole` [2].

Link: https://lore.kernel.org/rust-for-linux/CANiq72=4vX_tJMJLE6e+bg7ZECHkS-AQpm8GBzuK75G1EB7+Nw@mail.gmail.com/ [1]
Link: https://lore.kernel.org/linux-kbuild/20240728125527.690726-1-ojeda@kernel.org/ [2]
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20240902165535.1101978-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This commit is contained in:
Miguel Ojeda 2024-09-02 18:55:28 +02:00
parent ab309b6e08
commit 6e74c6b5a4
2 changed files with 33 additions and 0 deletions

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@ -60,6 +60,13 @@ config LLD_VERSION
default $(ld-version) if LD_IS_LLD
default 0
config RUSTC_VERSION
int
default $(shell,$(srctree)/scripts/rustc-version.sh $(RUSTC))
help
It does not depend on `RUST` since that one may need to use the version
in a `depends on`.
config RUST_IS_AVAILABLE
def_bool $(success,$(srctree)/scripts/rust_is_available.sh)
help

26
scripts/rustc-version.sh Executable file
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@ -0,0 +1,26 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# Usage: $ ./rustc-version.sh rustc
#
# Print the Rust compiler version in a 6 or 7-digit form.
# 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 + $3))
}
if output=$("$@" --version 2>/dev/null); then
set -- $output
get_canonical_version $2
else
echo 0
exit 1
fi