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| author | Nick Desaulniers <ndesaulniers@google.com> | 2021-08-16 13:25:01 -0700 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2021-09-03 08:12:38 +0900 |
| commit | 7d73c3e9c51400d3e0e755488050804e4d44737a (patch) | |
| tree | 3bbf3a455d7e601f08f7b552f2949b54ef4dbe11 /lib | |
| parent | 36f1386d341209bf5ec792938fbc0786b914f8dd (diff) | |
| download | lwn-7d73c3e9c51400d3e0e755488050804e4d44737a.tar.gz lwn-7d73c3e9c51400d3e0e755488050804e4d44737a.zip | |
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.debug | 2 |
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. |