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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`
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= 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>
90 lines
3.4 KiB
Makefile
90 lines
3.4 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0-only
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# cc-cross-prefix
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# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
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# Return first <prefix> where a <prefix>gcc is found in PATH.
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# If no gcc found in PATH with listed prefixes return nothing
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#
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# Note: '2>/dev/null' is here to force Make to invoke a shell. Otherwise, it
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# would try to directly execute the shell builtin 'command'. This workaround
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# should be kept for a long time since this issue was fixed only after the
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# GNU Make 4.2.1 release.
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cc-cross-prefix = $(firstword $(foreach c, $(1), \
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$(if $(shell command -v -- $(c)gcc 2>/dev/null), $(c))))
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# output directory for tests below
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TMPOUT = $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_$$$$
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# try-run
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# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
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# Exit code chooses option. "$$TMP" serves as a temporary file and is
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# automatically cleaned up.
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try-run = $(shell set -e; \
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TMP=$(TMPOUT)/tmp; \
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trap "rm -rf $(TMPOUT)" EXIT; \
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mkdir -p $(TMPOUT); \
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if ($(1)) >/dev/null 2>&1; \
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then echo "$(2)"; \
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else echo "$(3)"; \
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fi)
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# as-option
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# Usage: aflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
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as-option = $(call try-run,\
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$(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(1) -c -x assembler-with-cpp /dev/null -o "$$TMP",$(1),$(2))
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# as-instr
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# Usage: aflags-y += $(call as-instr,instr,option1,option2)
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as-instr = $(call try-run,\
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printf "%b\n" "$(1)" | $(CC) -Werror $(CLANG_FLAGS) $(KBUILD_AFLAGS) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o "$$TMP" -,$(2),$(3))
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# __cc-option
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# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
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__cc-option = $(call try-run,\
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$(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
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# cc-option
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# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
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cc-option = $(call __cc-option, $(CC),\
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$(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS),$(1),$(2))
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# cc-option-yn
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# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
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cc-option-yn = $(if $(call cc-option,$1),y,n)
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# cc-disable-warning
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# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
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cc-disable-warning = $(if $(call cc-option,-W$(strip $1)),-Wno-$(strip $1))
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# gcc-min-version
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# Usage: cflags-$(call gcc-min-version, 70100) += -foo
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gcc-min-version = $(call test-ge, $(CONFIG_GCC_VERSION), $1)
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# clang-min-version
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# Usage: cflags-$(call clang-min-version, 110000) += -foo
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clang-min-version = $(call test-ge, $(CONFIG_CLANG_VERSION), $1)
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# ld-option
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# Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
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ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
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# __rustc-option
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# Usage: MY_RUSTFLAGS += $(call __rustc-option,$(RUSTC),$(MY_RUSTFLAGS),-Cinstrument-coverage,-Zinstrument-coverage)
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# TODO: remove RUSTC_BOOTSTRAP=1 when we raise the minimum GNU Make version to 4.4
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__rustc-option = $(call try-run,\
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echo '#![allow(missing_docs)]#![feature(no_core)]#![no_core]' | RUSTC_BOOTSTRAP=1\
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$(1) --sysroot=/dev/null $(filter-out --sysroot=/dev/null,$(2)) $(3)\
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--crate-type=rlib --out-dir=$(TMPOUT) --emit=obj=- - >/dev/null,$(3),$(4))
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# rustc-option
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# Usage: rustflags-y += $(call rustc-option,-Cinstrument-coverage,-Zinstrument-coverage)
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rustc-option = $(call __rustc-option, $(RUSTC),\
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$(KBUILD_RUSTFLAGS),$(1),$(2))
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# rustc-option-yn
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# Usage: flag := $(call rustc-option-yn,-Cinstrument-coverage)
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rustc-option-yn = $(if $(call rustc-option,$1),y,n)
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