Re: [libvirt] [PATCHv3 1/3] build: Check for broken GCC -Wlogical-op in configure
On Wed, Dec 19, 2012 at 01:05:42PM +0100, Viktor Mihajlovski wrote:
On 12/19/2012 11:21 AM, Daniel P. Berrange wrote:
>On Wed, Dec 19, 2012 at 11:14:15AM +0100, Viktor Mihajlovski wrote:
>
>I think Eric means that on non-GCC this code:
>
># if BROKEN_GCC_WLOGICALOP
># pragma GCC diagnostic ignored "-Wlogical-op"
># endif
>
>
>will cause the compiler to complain "Unknown pragma GCC diagnostic..."
>since obviously non-GCC compilers don't understand GCC pragmas
>
>Daniel
>
I understood that part. My statement is that BROKEN_GCC_WLOGICALOP will
not be defined if configure was run on a system with non-GCC compiler.
Unless I oversaw something fundamental ... which I will never rule out.
I think it depends on what the compiler does with unknown -W flags.
In the configure test you created, there are 2 possible reasons
why the TRY_COMPILE can fail
- Using GCC with a broken -Wlogical-op impl
- Compiler which doesn't understand -Wlogical-op at all and treats
this is a fatal error
I think the solution here is to move the check into
virt-compiler-warnings.m4 and only look for a broken
GCC, if we have already validated that '-Wlogical-op'
is supported by the compiler
Regards,
Daniel
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