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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-05-09 13:57:10 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-20 08:18:45 +0200 |
| commit | ec22322218eca4c9fcafdbbf293a0f8faabfb2cb (patch) | |
| tree | 817db849b961b87029195c054a06ca716b5f7a48 /init | |
| parent | 9088569b56038c8750e2356a6b9274f980486c35 (diff) | |
| download | linux-stable-ec22322218eca4c9fcafdbbf293a0f8faabfb2cb.tar.gz linux-stable-ec22322218eca4c9fcafdbbf293a0f8faabfb2cb.tar.bz2 linux-stable-ec22322218eca4c9fcafdbbf293a0f8faabfb2cb.zip | |
Stop the ad-hoc games with -Wno-maybe-initialized
commit 78a5255ffb6a1af189a83e493d916ba1c54d8c75 upstream.
We have some rather random rules about when we accept the
"maybe-initialized" warnings, and when we don't.
For example, we consider it unreliable for gcc versions < 4.9, but also
if -O3 is enabled, or if optimizing for size. And then various kernel
config options disabled it, because they know that they trigger that
warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES).
And now gcc-10 seems to be introducing a lot of those warnings too, so
it falls under the same heading as 4.9 did.
At the same time, we have a very straightforward way to _enable_ that
warning when wanted: use "W=2" to enable more warnings.
So stop playing these ad-hoc games, and just disable that warning by
default, with the known and straight-forward "if you want to work on the
extra compiler warnings, use W=123".
Would it be great to have code that is always so obvious that it never
confuses the compiler whether a variable is used initialized or not?
Yes, it would. In a perfect world, the compilers would be smarter, and
our source code would be simpler.
That's currently not the world we live in, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 17 |
1 files changed, 0 insertions, 17 deletions
diff --git a/init/Kconfig b/init/Kconfig index ed0106b8d4f3..47035b5a46f6 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -26,22 +26,6 @@ config CLANG_VERSION config CC_HAS_ASM_GOTO def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC)) -config CC_HAS_WARN_MAYBE_UNINITIALIZED - def_bool $(cc-option,-Wmaybe-uninitialized) - help - GCC >= 4.7 supports this option. - -config CC_DISABLE_WARN_MAYBE_UNINITIALIZED - bool - depends on CC_HAS_WARN_MAYBE_UNINITIALIZED - default CC_IS_GCC && GCC_VERSION < 40900 # unreliable for GCC < 4.9 - help - GCC's -Wmaybe-uninitialized is not reliable by definition. - Lots of false positive warnings are produced in some cases. - - If this option is enabled, -Wno-maybe-uninitialzed is passed - to the compiler to suppress maybe-uninitialized warnings. - config CONSTRUCTORS bool depends on !UML @@ -1099,7 +1083,6 @@ config CC_OPTIMIZE_FOR_PERFORMANCE config CC_OPTIMIZE_FOR_SIZE bool "Optimize for size" - imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives help Enabling this option will pass "-Os" instead of "-O2" to your compiler resulting in a smaller kernel. |