Thanks for catching this - I had a specialized toolchain enabled which didn't exercise the `RUSTC_BOOTSTRAP` issue, and without an unexpected failure, didn't see the `--out-dir` flag conflict after I got the request to add it. Reviewed-By: Matthew Maurer <mmaurer@xxxxxxxxxx> On Tue, Oct 8, 2024 at 10:32 AM Alice Ryhl <aliceryhl@xxxxxxxxxx> wrote: > > 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> >
