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![Masahiro Yamada](/assets/img/avatar_default.png)
Paul Gortmaker reported a regression in the GCC version check. [1]
If you use GCC 4.8, the build breaks before showing the error message
"error Sorry, your version of GCC is too old - please use 4.9 or newer."
I do not want to apply his fix-up since it implies we would not be able
to remove any cc-option test. Anyway, I admit checking the GCC version
in <linux/compiler-gcc.h> is too late.
Almost at the same time, Linus also suggested to move the compiler
version error to Kconfig time. [2]
I unified the two similar scripts, gcc-version.sh and clang-version.sh
into cc-version.sh. The old scripts invoked the compiler multiple times
(3 times for gcc-version.sh, 4 times for clang-version.sh). I refactored
the code so the new one invokes the compiler just once, and also tried
my best to use shell-builtin commands where possible.
The new script runs faster.
$ time ./scripts/clang-version.sh clang
120000
real 0m0.029s
user 0m0.012s
sys 0m0.021s
$ time ./scripts/cc-version.sh clang
Clang 120000
real 0m0.009s
user 0m0.006s
sys 0m0.004s
cc-version.sh also shows an error message if the compiler is too old:
$ make defconfig CC=clang-9
*** Default configuration is based on 'x86_64_defconfig'
***
*** Compiler is too old.
*** Your Clang version: 9.0.1
*** Minimum Clang version: 10.0.1
***
scripts/Kconfig.include:46: Sorry, this compiler is not supported.
make[1]: *** [scripts/kconfig/Makefile:81: defconfig] Error 1
make: *** [Makefile:602: defconfig] Error 2
The new script takes care of ICC because we have <linux/compiler-intel.h>
although I am not sure if building the kernel with ICC is well-supported.
[1]: https://lore.kernel.org/r/20210110190807.134996-1-paul.gortmaker@windriver.com
[2]: https://lore.kernel.org/r/CAHk-=wh-+TMHPTFo1qs-MYyK7tZh-OQovA=pP3=e06aCVp6_kA@mail.gmail.com
Fixes: 87de84c914
("kbuild: remove cc-option test of -Werror=date-time")
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
57 lines
1.9 KiB
C
57 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_COMPILER_TYPES_H
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#error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
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#endif
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/* Compiler specific definitions for Clang compiler */
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/* same as gcc, this was present in clang-2.6 so we can assume it works
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* with any version that can compile the kernel
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*/
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#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
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/* all clang versions usable with the kernel support KASAN ABI version 5 */
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#define KASAN_ABI_VERSION 5
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#if __has_feature(address_sanitizer) || __has_feature(hwaddress_sanitizer)
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/* Emulate GCC's __SANITIZE_ADDRESS__ flag */
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#define __SANITIZE_ADDRESS__
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#define __no_sanitize_address \
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__attribute__((no_sanitize("address", "hwaddress")))
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#else
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#define __no_sanitize_address
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#endif
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#if __has_feature(thread_sanitizer)
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/* emulate gcc's __SANITIZE_THREAD__ flag */
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#define __SANITIZE_THREAD__
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#define __no_sanitize_thread \
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__attribute__((no_sanitize("thread")))
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#else
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#define __no_sanitize_thread
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#endif
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#if __has_feature(undefined_behavior_sanitizer)
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/* GCC does not have __SANITIZE_UNDEFINED__ */
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#define __no_sanitize_undefined \
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__attribute__((no_sanitize("undefined")))
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#else
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#define __no_sanitize_undefined
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#endif
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/*
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* Not all versions of clang implement the type-generic versions
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* of the builtin overflow checkers. Fortunately, clang implements
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* __has_builtin allowing us to avoid awkward version
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* checks. Unfortunately, we don't know which version of gcc clang
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* pretends to be, so the macro may or may not be defined.
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*/
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#if __has_builtin(__builtin_mul_overflow) && \
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__has_builtin(__builtin_add_overflow) && \
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__has_builtin(__builtin_sub_overflow)
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#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
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#endif
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#if __has_feature(shadow_call_stack)
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# define __noscs __attribute__((__no_sanitize__("shadow-call-stack")))
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#endif
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