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e72a076c62
Fix a few different compiler errors that cause rustc-option to give
wrong results.
If KBUILD_RUSTFLAGS or the flags being tested contain any -Z flags, then
the error below is generated. The RUSTC_BOOTSTRAP environment variable
is added to fix this error.
error: the option `Z` is only accepted on the nightly compiler
help: consider switching to a nightly toolchain: `rustup default nightly`
note: selecting a toolchain with `+toolchain` arguments require a rustup proxy;
see <https://rust-lang.github.io/rustup/concepts/index.html>
note: for more information about Rust's stability policy, see
<https://doc.rust-lang.org/book/appendix-07-nightly-rust.html#unstable-features>
error: 1 nightly option were parsed
Note that RUSTC_BOOTSTRAP is also defined in the top-level Makefile,
but Make-exported variables are unfortunately *not* inherited. That said,
this is changing as of commit 98da874c4303 ("[SV 10593] Export variables
to $(shell ...) commands"), which is part of Make 4.4.
The probe may also fail with the error message below. To fix it,
the /dev/null argument is replaced with a file containing the crate
attribute #![no_core]. The #![no_core] attribute ensures that rustc does
not look for the standard library. It's not possible to instead supply
a standard library (i.e. `core`) to rustc, as we need `rustc-option`
before the Rust standard library is compiled.
error[E0463]: can't find crate for `std`
|
= note: the `aarch64-unknown-none` target may not be installed
= help: consider downloading the target with `rustup target add aarch64-unknown-none`
= help: consider building the standard library from source with `cargo build -Zbuild-std`
The -o and --out-dir parameters are altered to fix this warning:
warning: ignoring --out-dir flag due to -o flag
The --sysroot flag is provided as we would otherwise require it to be
present in KBUILD_RUSTFLAGS. The --emit=obj flag is used to write the
resulting object file to /dev/null instead of writing it to a file
in $(TMPOUT).
I verified that the Kconfig version of rustc-option doesn't have the
same issues.
Fixes: c42297438a ("kbuild: rust: Define probing macros for rustc")
Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20241009-rustc-option-bootstrap-v3-1-5fa0d520efba@google.com
[ Reworded as discussed in the list. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.