Re: [Qemu-devel] [PULL 14/46] cpu-exec: drop dead assignment

[Peter Maydell]

On 10 February 2015 at 06:34, Michael Tokarev <address@hidden> wrote:
> From: Paolo Bonzini <address@hidden>
>
> All uses of TB inside cpu_exec are dominated by "tb = tb_find_fast(env)",
> and there are no uses after the switch statement.  So the assignment
> is dead, as reported by Coverity.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
> Signed-off-by: Michael Tokarev <address@hidden>
> ---
>  cpu-exec.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/cpu-exec.c b/cpu-exec.c
> index fa506e6..4ff1b23 100644
> --- a/cpu-exec.c
> +++ b/cpu-exec.c
> @@ -494,7 +494,6 @@ int cpu_exec(CPUArchState *env)
>                           * interrupt_request) which we will handle
>                           * next time around the loop.
>                           */
> -                        tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK);
>                          next_tb = 0;
>                          break;
>                      case TB_EXIT_ICOUNT_EXPIRED:

True, I guess, but presumably this means we're doing unnecessary
work in the next time round the loop re-finding the tb which we
already had...

(Also, why do we have a variable 'next_tb' which holds the
address of the *previous* TB? :-) I think the documentation
of the return value of tcg_qemu_tb_exec() is wrong too. Or
I've misunderstood the code.)

-- PMM