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| author | Nathan Chancellor <natechancellor@gmail.com> | 2020-03-26 12:41:55 -0700 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2020-04-09 00:13:45 +0900 |
| commit | afe956c577b2d5a3d9834e4424587c1ebcf90c4c (patch) | |
| tree | de9cf59d76030d40ef74194702dbaa1ca95897fe | |
| parent | e6abef610c7363cbd25205674b962031ef3bc790 (diff) | |
| download | linux-afe956c577b2d5a3d9834e4424587c1ebcf90c4c.tar.gz linux-afe956c577b2d5a3d9834e4424587c1ebcf90c4c.tar.bz2 linux-afe956c577b2d5a3d9834e4424587c1ebcf90c4c.zip | |
kbuild: Enable -Wtautological-compare
Currently, we disable -Wtautological-compare, which in turn disables a
bunch of more specific tautological comparison warnings that are useful
for the kernel such as -Wtautological-bitwise-compare. See clang's
documentation below for the other warnings that are suppressed by
-Wtautological-compare. Now that all of the major/noisy warnings have
been fixed, enable -Wtautological-compare so that more issues can be
caught at build time by various continuous integration setups.
-Wtautological-constant-out-of-range-compare is kept disabled under a
normal build but visible at W=1 because there are places in the kernel
where a constant or variable size can change based on the kernel
configuration. These are not fixed in a clean/concise way and the ones
I have audited so far appear to be harmless. It is not a subgroup but
rather just one warning so we do not lose out on much coverage by
default.
Link: https://github.com/ClangBuiltLinux/linux/issues/488
Link: http://releases.llvm.org/10.0.0/tools/clang/docs/DiagnosticsReference.html#wtautological-compare
Link: https://bugs.llvm.org/show_bug.cgi?id=42666
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
| -rw-r--r-- | Makefile | 2 | ||||
| -rw-r--r-- | scripts/Makefile.extrawarn | 1 |
2 files changed, 1 insertions, 2 deletions
@@ -747,8 +747,6 @@ ifdef CONFIG_CC_IS_CLANG KBUILD_CPPFLAGS += -Qunused-arguments KBUILD_CFLAGS += -Wno-format-invalid-specifier KBUILD_CFLAGS += -Wno-gnu -# Quiet clang warning: comparison of unsigned expression < 0 is always false -KBUILD_CFLAGS += -Wno-tautological-compare # CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the # source of a reference will be _MergedGlobals and not on of the whitelisted names. # See modpost pattern 2 diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index ca08f2fe7c34..4aea7cf71d11 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -49,6 +49,7 @@ KBUILD_CFLAGS += -Wno-format KBUILD_CFLAGS += -Wno-sign-compare KBUILD_CFLAGS += -Wno-format-zero-length KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) +KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare endif endif |