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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-19 11:10:17 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-19 11:10:17 -0700 |
| commit | 68df3755e383e6fecf2354a67b08f92f18536594 (patch) | |
| tree | a5091127ecb61f30c448ec2abb534509791a7d19 /Makefile | |
| parent | a1e4ee22863d41a6fbb24310d7951836cb6dafe7 (diff) | |
| download | lwn-68df3755e383e6fecf2354a67b08f92f18536594.tar.gz lwn-68df3755e383e6fecf2354a67b08f92f18536594.zip | |
Add '-fwrapv' to gcc CFLAGS
This makes sure that gcc doesn't try to optimize away wrapping
arithmetic, which the kernel occasionally uses for overflow testing, ie
things like
if (ptr + offset < ptr)
which technically is undefined for non-unsigned types. See
http://bugzilla.kernel.org/show_bug.cgi?id=12597
for details.
Not all versions of gcc support it, so we need to make it conditional
(it looks like it was introduced in gcc-3.4).
Reminded-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 1 |
1 files changed, 1 insertions, 0 deletions
@@ -347,6 +347,7 @@ KBUILD_CPPFLAGS := -D__KERNEL__ KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ -fno-strict-aliasing -fno-common \ -Werror-implicit-function-declaration +KBUILD_CFLAGS += $(call cc-option,-fwrapv) KBUILD_AFLAGS := -D__ASSEMBLY__ # Read KERNELRELEASE from include/config/kernel.release (if it exists) |