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kbuild: rust: add CONFIG_RUSTC_LLVM_VERSION

Each version of Rust supports a range of LLVM versions. There are cases where
we want to gate a config on the LLVM version instead of the Rust version.
Normalized cfi integer tags are one example [1].

The invocation of rustc-version is being moved from init/Kconfig to
scripts/Kconfig.include for consistency with cc-version.

Link: https://lore.kernel.org/all/20240925-cfi-norm-kasan-fix-v1-1-0328985cdf33@google.com/ [1]
Signed-off-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20241011114040.3900487-1-gary@garyguo.net
[ Added missing `-llvm` to the Usage documentation. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This commit is contained in:
Gary Guo 2024-10-11 12:40:33 +01:00 committed by Miguel Ojeda
parent e72a076c62
commit af0121c2d3
3 changed files with 30 additions and 1 deletions

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@ -62,7 +62,7 @@ config LLD_VERSION
config RUSTC_VERSION config RUSTC_VERSION
int int
default $(shell,$(srctree)/scripts/rustc-version.sh $(RUSTC)) default $(rustc-version)
help help
It does not depend on `RUST` since that one may need to use the version It does not depend on `RUST` since that one may need to use the version
in a `depends on`. in a `depends on`.
@ -78,6 +78,10 @@ config RUST_IS_AVAILABLE
In particular, the Makefile target 'rustavailable' is useful to check In particular, the Makefile target 'rustavailable' is useful to check
why the Rust toolchain is not being detected. why the Rust toolchain is not being detected.
config RUSTC_LLVM_VERSION
int
default $(rustc-llvm-version)
config CC_CAN_LINK config CC_CAN_LINK
bool bool
default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT

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@ -65,6 +65,9 @@ cc-option-bit = $(if-success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null,$
m32-flag := $(cc-option-bit,-m32) m32-flag := $(cc-option-bit,-m32)
m64-flag := $(cc-option-bit,-m64) m64-flag := $(cc-option-bit,-m64)
rustc-version := $(shell,$(srctree)/scripts/rustc-version.sh $(RUSTC))
rustc-llvm-version := $(shell,$(srctree)/scripts/rustc-llvm-version.sh $(RUSTC))
# $(rustc-option,<flag>) # $(rustc-option,<flag>)
# Return y if the Rust compiler supports <flag>, n otherwise # Return y if the Rust compiler supports <flag>, n otherwise
# Calls to this should be guarded so that they are not evaluated if # Calls to this should be guarded so that they are not evaluated if

22
scripts/rustc-llvm-version.sh Executable file
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@ -0,0 +1,22 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# Usage: $ ./rustc-llvm-version.sh rustc
#
# Print the LLVM version that the Rust compiler uses in a 6 digit form.
# Convert the version string x.y.z to a canonical up-to-6-digits form.
get_canonical_version()
{
IFS=.
set -- $1
echo $((10000 * $1 + 100 * $2 + $3))
}
if output=$("$@" --version --verbose 2>/dev/null | grep LLVM); then
set -- $output
get_canonical_version $3
else
echo 0
exit 1
fi