Re: [Qemu-devel] [PATCH] Fix comparisons between implicit booleans and integers.

[Paolo Bonzini <pbonzini@redhat.com>]

On 30/01/2015 12:52, Richard W.M. Jones wrote:
> In GCC 5 there is a new warning (-Wlogical-not-parentheses) which
> prevents you from writing:
> 
>   if (<some implicitly boolean expression> == <an int>) ...
> 
> A typical error would be:
> 
> kvm-all.c: In function ‘kvm_set_migration_log’:
> kvm-all.c:383:54: error: logical not is only applied to the left hand side of comparison [-Werror=logical-not-parentheses]
>          if (!!(mem->flags & KVM_MEM_LOG_DIRTY_PAGES) == enable) {
> 
> Fix a few places where the build is now broken in GCC 5.
> 
> The warning isn't even consistent, as with the place in
> hw/net/virtio-net.c where I had to cast an obviously boolean
> expression to bool.

The other two places are fine cleanups, but really I would just suppress
the warning in configure...

Paolo

> Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
> ---
>  hw/net/virtio-net.c | 2 +-
>  kvm-all.c           | 2 +-
>  qemu-img.c          | 3 ++-
>  3 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 45da34a..ba6afb8 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -121,7 +121,7 @@ static void virtio_net_vhost_status(VirtIONet *n, uint8_t status)
>      }
>  
>      if (!!n->vhost_started ==
> -        (virtio_net_started(n, status) && !nc->peer->link_down)) {
> +        (bool) (virtio_net_started(n, status) && !nc->peer->link_down)) {
>          return;
>      }
>      if (!n->vhost_started) {
> diff --git a/kvm-all.c b/kvm-all.c
> index 2f21a4e..b6d4387 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -366,7 +366,7 @@ static void kvm_log_stop(MemoryListener *listener,
>      }
>  }
>  
> -static int kvm_set_migration_log(int enable)
> +static int kvm_set_migration_log(bool enable)
>  {
>      KVMState *s = kvm_state;
>      KVMSlot *mem;
> diff --git a/qemu-img.c b/qemu-img.c
> index 4e9a7f5..acf70fa 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -977,7 +977,8 @@ static int is_allocated_sectors_min(const uint8_t *buf, int n, int *pnum,
>  static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n,
>      int *pnum)
>  {
> -    int res, i;
> +    bool res;
> +    int i;
>  
>      if (n <= 0) {
>          *pnum = 0;
>