On Fri, Jan 15, 2021 at 03:07:09AM +0900, Masahiro Yamada wrote: > 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 similar two scripts, gcc-version.sh and clang-version.sh > into the new 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 > > The cc-version.sh also shows the error if the compiler is 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 > > I removed the clang version check from <linux/compiler-clang.h> > > For now, I did not touch <linux/compiler-gcc.h> in order to avoid > merge conflict with [3], which has been queued up in the arm64 tree. > We will be able to clean it up later. > > 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://lkml.org/lkml/2021/1/10/250 > [2] https://lkml.org/lkml/2021/1/12/1708 > [3] https://lkml.org/lkml/2021/1/12/1533 > > Fixes: 87de84c9140e ("kbuild: remove cc-option test of -Werror=date-time") > Reported-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> > Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Tested-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
