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| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2021-09-13 16:45:28 -0500 |
|---|---|---|
| committer | Gustavo A. R. Silva <gustavoars@kernel.org> | 2021-10-13 14:48:18 -0500 |
| commit | 9bed5200e04d2a3dcd3a420d249e947eac7ec7c1 (patch) | |
| tree | 5dfd844c4b7ba0f5a3953ad192998bcb66537466 | |
| parent | 02900f428d3c7acd89b77784bec33ddec7b750a4 (diff) | |
| download | linux-9bed5200e04d2a3dcd3a420d249e947eac7ec7c1.tar.gz | |
Makefile: Enable -Wimplicit-fallthrough for Clang
With the recent fixes for fallthrough warnings, it is now possible to
enable -Wimplicit-fallthrough for Clang.
Special thanks to Nathan Chancellor who fixed the Clang bug[1][2]
that put the application of this patch to a halt, temporarily. This
bugfix only appears in Clang 14.0.0, so older versions still contain
the bug and -Wimplicit-fallthrough won't be enabled for them, for
now.
This concludes a long journey and now we are finally getting rid
of the unintentional fallthrough bug-class in the kernel, entirely. :)
[1] https://github.com/llvm/llvm-project/commit/9ed4a94d6451046a51ef393cd62f00710820a7e8
[2] https://bugs.llvm.org/show_bug.cgi?id=51094
Link: https://github.com/KSPP/linux/issues/115
Link: https://github.com/ClangBuiltLinux/linux/issues/236
[The conditional "ifneq" was idea of Nathan]
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
| -rw-r--r-- | Makefile | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Makefile b/Makefile index 5e7c1d8544412..eb44b3b0c5bce 100644 --- a/Makefile +++ b/Makefile @@ -796,6 +796,14 @@ KBUILD_CFLAGS += -Wno-gnu # source of a reference will be _MergedGlobals and not on of the whitelisted names. # See modpost pattern 2 KBUILD_CFLAGS += -mno-global-merge +# Warn about unmarked fall-throughs in switch statement as long as +# -Wunreachable-code-fallthrough is present. Clang prior to 14 +# warned on unreachable fallthroughs with -Wimplicit-fallthrough, +# which is unacceptable due to IS_ENABLED(). +# https://bugs.llvm.org/show_bug.cgi?id=51094 +ifneq ($(call cc-option,-Wunreachable-code-fallthrough),) +KBUILD_CFLAGS += -Wimplicit-fallthrough +endif else # Warn about unmarked fall-throughs in switch statement. |