Re: [Qemu-devel] [PATCH] ipmi: Add parenthesis around some macro parameters

[Eric Blake]

On 12/22/2016 08:30 AM, address@hidden wrote:
> From: Corey Minyard <address@hidden>
> 
> Macro parameters should almost always have () around them when used.
> llvm reported an error on this.
> 
> Reported in https://bugs.launchpad.net/bugs/1651167
> 
> Signed-off-by: Corey Minyard <address@hidden>
> ---
>  hw/ipmi/isa_ipmi_bt.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/ipmi/isa_ipmi_bt.c b/hw/ipmi/isa_ipmi_bt.c
> index f036617..8a97314 100644
> --- a/hw/ipmi/isa_ipmi_bt.c
> +++ b/hw/ipmi/isa_ipmi_bt.c
> @@ -40,37 +40,37 @@
>  #define IPMI_BT_CLR_WR_MASK        (1 << IPMI_BT_CLR_WR_BIT)
>  #define IPMI_BT_GET_CLR_WR(d)      (((d) >> IPMI_BT_CLR_WR_BIT) & 0x1)
>  #define IPMI_BT_SET_CLR_WR(d, v)   (d) = (((d) & ~IPMI_BT_CLR_WR_MASK) | \

Still under-parenthesized, if the result of IPMI_BT_SET_CLR_WR() is used
in any larger expression;

> -                                       (((v & 1) << IPMI_BT_CLR_WR_BIT)))
> +                                       ((((v) & 1) << IPMI_BT_CLR_WR_BIT)))

and at the same time, you (still) have a redundant set on the second line.

Better would be:

((d) = (((d) & ~IPMI_BD_CLR_WR_MASK) | \
        (((v) & 1) << IPMI_BT_CLR_WR_BIT)))

>  
>  #define IPMI_BT_CLR_RD_MASK        (1 << IPMI_BT_CLR_RD_BIT)
>  #define IPMI_BT_GET_CLR_RD(d)      (((d) >> IPMI_BT_CLR_RD_BIT) & 0x1)
>  #define IPMI_BT_SET_CLR_RD(d, v)   (d) = (((d) & ~IPMI_BT_CLR_RD_MASK) | \
> -                                       (((v & 1) << IPMI_BT_CLR_RD_BIT)))
> +                                       ((((v) & 1) << IPMI_BT_CLR_RD_BIT)))

and again, throughout the patch.


-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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