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authorNick Desaulniers <ndesaulniers@google.com>2021-08-16 13:25:01 -0700
committerMasahiro Yamada <masahiroy@kernel.org>2021-09-03 08:12:38 +0900
commit7d73c3e9c51400d3e0e755488050804e4d44737a (patch)
tree3bbf3a455d7e601f08f7b552f2949b54ef4dbe11 /lib
parent36f1386d341209bf5ec792938fbc0786b914f8dd (diff)
downloadlinux-7d73c3e9c51400d3e0e755488050804e4d44737a.tar.gz
Makefile: remove stale cc-option checks
cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug2
1 files changed, 2 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 5ddd575159fb..7d3d29203a72 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -365,6 +365,7 @@ config STRIP_ASM_SYMS
config READABLE_ASM
bool "Generate readable assembler code"
depends on DEBUG_KERNEL
+ depends on CC_IS_GCC
help
Disable some compiler optimizations that tend to generate human unreadable
assembler output. This may make the kernel slightly slower, but it helps
@@ -383,6 +384,7 @@ config HEADERS_INSTALL
config DEBUG_SECTION_MISMATCH
bool "Enable full Section mismatch analysis"
+ depends on CC_IS_GCC
help
The section mismatch analysis checks if there are illegal
references from one section to another section.