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 The probe may also fail incorrectly with the below error message. To fix it, the /dev/null argument is replaced with a new rust/probe.rs file that doesn't need even the core part of the standard library. 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 I verified that the Kconfig version of rustc-option doesn't have the same issues. Fixes: c42297438aee ("kbuild: rust: Define probing macros for rustc") Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx> --- Changes in v2: - Add `export` to RUSTC_BOOTSTRAP. - Fix error about core being missing. - Fix warning about -o flag. - Link to v1: https://lore.kernel.org/r/20241008-rustc-option-bootstrap-v1-1-9eb06261d4f7@xxxxxxxxxx --- rust/probe.rs | 7 +++++++ scripts/Makefile.compiler | 5 +++-- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/rust/probe.rs b/rust/probe.rs new file mode 100644 index 000000000000..bf024e394408 --- /dev/null +++ b/rust/probe.rs @@ -0,0 +1,7 @@ +//! Nearly empty file passed to rustc-option by Make. +//! +//! The no_core attribute is needed because rustc-option otherwise fails due to +//! not being able to find the core part of the standard library. + +#![feature(no_core)] +#![no_core] diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler index 057305eae85c..08d5b7177ea8 100644 --- a/scripts/Makefile.compiler +++ b/scripts/Makefile.compiler @@ -21,6 +21,7 @@ TMPOUT = $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_$$$$ # automatically cleaned up. try-run = $(shell set -e; \ TMP=$(TMPOUT)/tmp; \ + export RUSTC_BOOTSTRAP=1; \ trap "rm -rf $(TMPOUT)" EXIT; \ mkdir -p $(TMPOUT); \ if ($(1)) >/dev/null 2>&1; \ @@ -76,7 +77,7 @@ ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3)) # __rustc-option # Usage: MY_RUSTFLAGS += $(call __rustc-option,$(RUSTC),$(MY_RUSTFLAGS),-Cinstrument-coverage,-Zinstrument-coverage) __rustc-option = $(call try-run,\ - $(1) $(2) $(3) --crate-type=rlib /dev/null --out-dir=$$TMPOUT -o "$$TMP",$(3),$(4)) + $(1) $(2) $(3) --crate-type=rlib $(srctree)/rust/probe.rs --out-dir=$$TMP,$(3),$(4)) # rustc-option # Usage: rustflags-y += $(call rustc-option,-Cinstrument-coverage,-Zinstrument-coverage) @@ -86,4 +87,4 @@ rustc-option = $(call __rustc-option, $(RUSTC),\ # rustc-option-yn # Usage: flag := $(call rustc-option-yn,-Cinstrument-coverage) rustc-option-yn = $(call try-run,\ - $(RUSTC) $(KBUILD_RUSTFLAGS) $(1) --crate-type=rlib /dev/null --out-dir=$$TMPOUT -o "$$TMP",y,n) + $(RUSTC) $(KBUILD_RUSTFLAGS) $(1) --crate-type=rlib $(srctree)/rust/probe.rs --out-dir=$$TMP,y,n) --- base-commit: 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b change-id: 20241008-rustc-option-bootstrap-607e5bf3114c Best regards, -- Alice Ryhl <aliceryhl@xxxxxxxxxx>
