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Re: [Qemu-devel] [PATCH v3 2/4] compiler: rework BUG_ON using a struct
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH v3 2/4] compiler: rework BUG_ON using a struct |
Date: |
Fri, 20 Jan 2017 08:44:15 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) |
Eric Blake <address@hidden> writes:
> On 01/19/2017 03:07 PM, Michael S. Tsirkin wrote:
>> There are theoretical concerns that some compilers might not trigger
>> build failures on attempts to define an array of size -1 and make it a
>> variable sized array instead.
>
> Rather, the concern is that if someone changes code so that the 'x' of
> QEMU_BUILD_BUG_ON(x) is no longer a compile time constant, we want a
> compile-time failure rather than a runtime variable-sized array that may
> or may not crash.
>> Let rewrite using a struct with a negative
>> bit field size instead as there are no dynamic bit field sizes. This is
>> similar to what Linux does.
>>
>> Signed-off-by: Michael S. Tsirkin <address@hidden>
>> ---
>> include/qemu/compiler.h | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>
> I don't know if you want to tweak the commit wording, but I'm okay with
> the patch itself.
For what it's worth, I'd prefer a rewording.
Re: [Qemu-devel] [PATCH v3 2/4] compiler: rework BUG_ON using a struct, Dr. David Alan Gilbert, 2017/01/20
[Qemu-devel] [PATCH v3 3/4] compiler: expression version of QEMU_BUILD_BUG_ON, Michael S. Tsirkin, 2017/01/19