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Re: [Xen-devel] [PATCH v2] dom0-build: fix build with clang5
Hi,
On 7/17/19 7:47 AM, Jan Beulich wrote:
With non-empty CONFIG_DOM0_MEM clang5 produces
dom0_build.c:344:24: error: use of logical '&&' with constant operand
[-Werror,-Wconstant-logical-operand]
if ( !dom0_mem_set && CONFIG_DOM0_MEM[0] )
^ ~~~~~~~~~~~~~~~~~~
dom0_build.c:344:24: note: use '&' for a bitwise operation
if ( !dom0_mem_set && CONFIG_DOM0_MEM[0] )
^~
&
dom0_build.c:344:24: note: remove constant to silence this warning
if ( !dom0_mem_set && CONFIG_DOM0_MEM[0] )
~^~~~~~~~~~~~~~~~~~~~~
1 error generated.
Obviously neither of the two suggestions are an option here. Oddly
enough swapping the operands of the && helps, while e.g. casting or
parenthesizing doesn't. Another workable variant looks to be the use of
!! on the constant.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v2: Also adjust the Arm incarnation of the same construct.
---
I'm open to going the !! or yet some different route (but not really the
suggested strlen() one). No matter which one we choose, I'm afraid it is
going to remain guesswork what newer (and future) versions of clang will
choke on.
I quite like the strlen one, however looking around online this may not
solve the problem. AFAIK, Clang is not happy because the constant is not
a boolean.
So !! or != 0 should work here.
Cheers,
--
Julien Grall
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