Messages in this thread | | | Subject | Re: [PATCH v2] LLVMLinux: Remove warning about returning an uninitialized variable | From | James Bottomley <> | Date | Sat, 22 Mar 2014 09:29:46 -0700 |
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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).
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.
James
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