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| author | Jeff King <peff@peff.net> | 2025-03-17 16:53:29 -0700 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2025-03-17 17:31:28 -0700 |
| commit | 16f5d967e2267ea37cd29d7aee21994921b6b98c (patch) | |
| tree | d305338726937e38c1a8d44b51af7d837a845ca6 | |
| parent | git-compat-util: add NOT_CONSTANT macro and use it in atfork_prepare() (diff) | |
| download | git-16f5d967e2267ea37cd29d7aee21994921b6b98c.tar.gz git-16f5d967e2267ea37cd29d7aee21994921b6b98c.zip | |
config.mak.dev: enable -Wunreachable-code
Having the compiler point out unreachable code can help avoid bugs, like
the one discussed in:
https://lore.kernel.org/git/20250307195057.GA3675279@coredump.intra.peff.net/
In that case it was found by Coverity, but finding it earlier saves
everybody time and effort.
We can use -Wunreachable-code to get some help from the compiler here.
Interestingly, this is a noop in gcc. It was a real warning up until gcc
4.x, when it was removed for being too flaky, but they left the
command-line option to avoid breaking users. See:
https://stackoverflow.com/questions/17249934/why-does-gcc-not-warn-for-unreachable-code
However, clang does implement this option, and it finds the case
mentioned above (and no other cases within the code base). And since we
run clang in several of our CI jobs, that's enough to get an early
warning of breakage.
We could enable it only for clang, but since gcc is happy to ignore it,
it's simpler to just turn it on for all developer builds.
Signed-off-by: Jeff King <peff@peff.net>
[jc: squashed meson.build change sent by Patrick]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
| -rw-r--r-- | config.mak.dev | 1 | ||||
| -rw-r--r-- | meson.build | 1 |
2 files changed, 2 insertions, 0 deletions
diff --git a/config.mak.dev b/config.mak.dev index 0fd8cc4d35..95b7bc46ae 100644 --- a/config.mak.dev +++ b/config.mak.dev @@ -39,6 +39,7 @@ DEVELOPER_CFLAGS += -Wunused DEVELOPER_CFLAGS += -Wvla DEVELOPER_CFLAGS += -Wwrite-strings DEVELOPER_CFLAGS += -fno-common +DEVELOPER_CFLAGS += -Wunreachable-code ifneq ($(filter clang4,$(COMPILER_FEATURES)),) DEVELOPER_CFLAGS += -Wtautological-constant-out-of-range-compare diff --git a/meson.build b/meson.build index f5c9dfa95b..0c1904b94b 100644 --- a/meson.build +++ b/meson.build @@ -698,6 +698,7 @@ if get_option('warning_level') in ['2','3', 'everything'] and compiler.get_argum '-Woverflow', '-Wpointer-arith', '-Wstrict-prototypes', + '-Wunreachable-code', '-Wunused', '-Wvla', '-Wwrite-strings', |