Re: [PATCH] tools/kdd: silence gcc 8 warning a different way

From: Wei Liu <wei.liu2@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Juergen Gross <jgross@suse.com>, Wei Liu <wei.liu2@citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>,
	tim@xen.org, Marek Marczykowski <marmarek@invisiblethingslab.com>,
	xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH] tools/kdd: silence gcc 8 warning a different way
Date: Mon, 16 Apr 2018 09:29:49 +0100	[thread overview]
Message-ID: <20180416082948.g6yhqwilqlorfciw@citrix.com> (raw)
In-Reply-To: <5ACF678102000078001BAA8E@prv1-mh.provo.novell.com>

Cc Tim

On Thu, Apr 12, 2018 at 06:04:49AM -0600, Jan Beulich wrote:
> Older gcc doesn't like "#pragma GCC diagnostic" inside functions.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> --- a/tools/debugger/kdd/kdd.c
> +++ b/tools/debugger/kdd/kdd.c
> @@ -695,10 +695,10 @@ static void kdd_handle_read_ctrl(kdd_sta
>              KDD_LOG(s, "Request outside of known control space\n");
>              len = 0;
>          } else {
> -#pragma GCC diagnostic push
> -#pragma GCC diagnostic ignored "-Warray-bounds"
> -            memcpy(buf, ((uint8_t *)&ctrl.c32) + offset, len);
> -#pragma GCC diagnostic pop
> +            /* Suppress bogus gcc 8 "out of bounds" warning. */
> +            const uint8_t *src;
> +            asm ("" : "=g" (src) : "0" ((uint8_t *)&ctrl.c32 + offset));
> +            memcpy(buf, src, len);
>          }
>      }
>  
> 
> 
> 

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