Re: [Qemu-devel] [PATCH 2/3] sparc64: implement global translation table entries

[Blue Swirl <blauwirbel@gmail.com>]

On 5/3/10, Igor Kovalenko <igor.v.kovalenko@gmail.com> wrote:
> On Tue, May 4, 2010 at 12:06 AM, Blue Swirl <blauwirbel@gmail.com> wrote:
>  > On 5/3/10, Igor V. Kovalenko <igor.v.kovalenko@gmail.com> wrote:
>  >> From: Igor V. Kovalenko <igor.v.kovalenko@gmail.com>
>  >>
>  >>  - match global tte against any context
>  >>  - show global tte in MMU dump
>  >>
>  >>  Signed-off-by: Igor V. Kovalenko <igor.v.kovalenko@gmail.com>
>  >
>  > I get this error:
>  >  CC    sparc64-softmmu/op_helper.o
>  > cc1: warnings being treated as errors
>  > /src/qemu/target-sparc/op_helper.c: In function 'demap_tlb':
>  > /src/qemu/target-sparc/op_helper.c:129: error: 'context' may be used
>  > uninitialized in this function
>  >
>
>
> My gcc (Gentoo 4.4.3-r2 p1.2) is silent, and looking at the change all
>  4 possible cases are handled in switch statement.

I think gcc is not intelligent enough to know that x & 3 has only 4
possible cases. :-)

>  It should initializes context in 3 usable cases and returns from the
>  4th which is reserved.
>  How do we fix this issue?

I'd add a default case to one of the cases. Another possibility is to
initialize the context with 0 and then make one of the cases empty.