Messages in this thread | | | Date | Sat, 22 Mar 2014 09:37:36 -0700 | From | Behan Webster <> | Subject | Re: [PATCH v2] LLVMLinux: Remove warning about returning an uninitialized variable |
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On 03/22/14 09:29, James Bottomley wrote: > On Sat, 2014-03-22 at 08:48 -0700, behanw@converseincode.com wrote: >> From: Behan Webster <behanw@converseincode.com> >> >> Fix uninitialized return code in default case in cmpxchg-local.h >> >> This patch fixes the code to prevent an uninitialized return value that is detected >> when compiling with clang. The bug produces numerous warnings when compiling the >> Linux kernel with clang. >> >> Signed-off-by: Behan Webster <behanw@converseincode.com> >> Signed-off-by: Mark Charlebois <charlebm@gmail.com> >> --- >> include/asm-generic/cmpxchg-local.h | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/include/asm-generic/cmpxchg-local.h b/include/asm-generic/cmpxchg-local.h >> index d8d4c89..9112111 100644 >> --- a/include/asm-generic/cmpxchg-local.h >> +++ b/include/asm-generic/cmpxchg-local.h >> @@ -41,6 +41,7 @@ static inline unsigned long __cmpxchg_local_generic(volatile void *ptr, >> break; >> default: >> wrong_size_cmpxchg(ptr); >> + __builtin_unreachable(); > No, that's got to be unreachable() so that it works in all compilers, > (__builtin_unreachable is a gcc-4 ism). It is also supported by clang.
> Got to say this still looks wrong. If wrong_size_cmpxchg() cannot > return, the function should be annotated as such with __noreturn (like > panic()) so the unreachable() should be superfluous. Okay. I can try that instead.
Thanks,
Behan
-- Behan Webster behanw@converseincode.com
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