aec6c60a01
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
2.1 KiB
Plaintext
57 lines
2.1 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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# Kconfig helper macros
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# Convenient variables
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comma := ,
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quote := "
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squote := '
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empty :=
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space := $(empty) $(empty)
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dollar := $
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right_paren := )
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left_paren := (
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# $(if-success,<command>,<then>,<else>)
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# Return <then> if <command> exits with 0, <else> otherwise.
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if-success = $(shell,{ $(1); } >/dev/null 2>&1 && echo "$(2)" || echo "$(3)")
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# $(success,<command>)
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# Return y if <command> exits with 0, n otherwise
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success = $(if-success,$(1),y,n)
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# $(failure,<command>)
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# Return n if <command> exits with 0, y otherwise
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failure = $(if-success,$(1),n,y)
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# $(cc-option,<flag>)
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# Return y if the compiler supports <flag>, n otherwise
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cc-option = $(success,mkdir .tmp_$$$$; trap "rm -rf .tmp_$$$$" EXIT; $(CC) -Werror $(CLANG_FLAGS) $(1) -c -x c /dev/null -o .tmp_$$$$/tmp.o)
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# $(ld-option,<flag>)
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# Return y if the linker supports <flag>, n otherwise
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ld-option = $(success,$(LD) -v $(1))
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# $(as-instr,<instr>)
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# Return y if the assembler supports <instr>, n otherwise
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as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler -o /dev/null -)
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# check if $(CC) and $(LD) exist
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$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)
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$(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found)
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# Get the compiler name, version, and error out if it is not supported.
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cc-info := $(shell,$(srctree)/scripts/cc-version.sh $(CC))
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$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this compiler is not supported.)
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cc-name := $(shell,set -- $(cc-info) && echo $1)
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cc-version := $(shell,set -- $(cc-info) && echo $2)
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# Fail if the linker is gold as it's not capable of linking the kernel proper
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$(error-if,$(success, $(LD) -v | grep -q gold), gold linker '$(LD)' not supported)
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# machine bit flags
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# $(m32-flag): -m32 if the compiler supports it, or an empty string otherwise.
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# $(m64-flag): -m64 if the compiler supports it, or an empty string otherwise.
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cc-option-bit = $(if-success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null,$(1))
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m32-flag := $(cc-option-bit,-m32)
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m64-flag := $(cc-option-bit,-m64)
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