Re: [Qemu-devel] [PATCH target-arm v2] display: avoid multi-statement macro

[Laszlo Ersek <lersek@redhat.com>]

On 01/24/14 20:08, Paolo Bonzini wrote:
> For blizzard, pl110 and tc6393xb this is harmless, but for pxa2xx
> Coverity noticed that it is used inside an "if" statement.
> Fix it because it's the file with the highest number of defects
> in the whole QEMU tree!  Use "do...while(0)", or just remove the
> semicolon if there's a single statement in the macro.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  hw/display/blizzard_template.h | 22 ++++++++++++++++------
>  hw/display/pl110_template.h    | 12 ++++++++----
>  hw/display/pxa2xx_template.h   | 22 +++++++++++++++++-----
>  hw/display/tc6393xb_template.h | 14 +++++++++-----
>  4 files changed, 56 insertions(+), 27 deletions(-)
> 
> diff --git a/hw/display/blizzard_template.h b/hw/display/blizzard_template.h
> index a8a8899..c48a9b3 100644
> --- a/hw/display/blizzard_template.h
> +++ b/hw/display/blizzard_template.h
> @@ -21,21 +21,31 @@
>  #define SKIP_PIXEL(to)		to += deststep
>  #if DEPTH == 8
>  # define PIXEL_TYPE		uint8_t
> -# define COPY_PIXEL(to, from)	*to = from; SKIP_PIXEL(to)
> +# define COPY_PIXEL(to, from)	do { *to = from; SKIP_PIXEL(to); } while(0)
>  # define COPY_PIXEL1(to, from)	*to ++ = from
>  #elif DEPTH == 15 || DEPTH == 16
>  # define PIXEL_TYPE		uint16_t
> -# define COPY_PIXEL(to, from)	*to = from; SKIP_PIXEL(to)
> +# define COPY_PIXEL(to, from)	do { *to = from; SKIP_PIXEL(to); } while(0)
>  # define COPY_PIXEL1(to, from)	*to ++ = from
>  #elif DEPTH == 24
>  # define PIXEL_TYPE		uint8_t
> -# define COPY_PIXEL(to, from)	\
> -    to[0] = from; to[1] = (from) >> 8; to[2] = (from) >> 16; SKIP_PIXEL(to)
> +# define COPY_PIXEL(to, from) \
> +    do {                      \
> +        to[0] = from;         \
> +        to[1] = (from) >> 8;  \
> +        to[2] = (from) >> 16; \
> +        SKIP_PIXEL(to);       \
> +    } while(0)
> +
>  # define COPY_PIXEL1(to, from)	\
> -    *to ++ = from; *to ++ = (from) >> 8; *to ++ = (from) >> 16
> +    do {                       \
> +        *to ++ = from;         \
> +        *to ++ = (from) >> 8;  \
> +        *to ++ = (from) >> 16; \
> +    } while(0)
>  #elif DEPTH == 32
>  # define PIXEL_TYPE		uint32_t
> -# define COPY_PIXEL(to, from)	*to = from; SKIP_PIXEL(to)
> +# define COPY_PIXEL(to, from)	do { *to = from; SKIP_PIXEL(to); } while(0)
>  # define COPY_PIXEL1(to, from)	*to ++ = from
>  #else
>  # error unknown bit depth
> diff --git a/hw/display/pl110_template.h b/hw/display/pl110_template.h
> index e738e4a..f685b26 100644
> --- a/hw/display/pl110_template.h
> +++ b/hw/display/pl110_template.h
> @@ -14,12 +14,16 @@
>  #if BITS == 8
>  #define COPY_PIXEL(to, from) *(to++) = from
>  #elif BITS == 15 || BITS == 16
> -#define COPY_PIXEL(to, from) *(uint16_t *)to = from; to += 2;
> +#define COPY_PIXEL(to, from) do { *(uint16_t *)to = from; to += 2; } while(0)
>  #elif BITS == 24
> -#define COPY_PIXEL(to, from) \
> -  *(to++) = from; *(to++) = (from) >> 8; *(to++) = (from) >> 16
> +#define COPY_PIXEL(to, from)    \
> +    do {                        \
> +        *(to++) = from;         \
> +        *(to++) = (from) >> 8;  \
> +        *(to++) = (from) >> 16; \
> +    } while(0)
>  #elif BITS == 32
> -#define COPY_PIXEL(to, from) *(uint32_t *)to = from; to += 4;
> +#define COPY_PIXEL(to, from) do { *(uint32_t *)to = from; to += 4; } while(0)
>  #else
>  #error unknown bit depth
>  #endif
> diff --git a/hw/display/pxa2xx_template.h b/hw/display/pxa2xx_template.h
> index 1cbe36c..9aed90e 100644
> --- a/hw/display/pxa2xx_template.h
> +++ b/hw/display/pxa2xx_template.h
> @@ -11,14 +11,26 @@
>  
>  # define SKIP_PIXEL(to)		to += deststep
>  #if BITS == 8
> -# define COPY_PIXEL(to, from)	*to = from; SKIP_PIXEL(to)
> +# define COPY_PIXEL(to, from)	do { *to = from; SKIP_PIXEL(to); } while(0)
>  #elif BITS == 15 || BITS == 16
> -# define COPY_PIXEL(to, from)	*(uint16_t *) to = from; SKIP_PIXEL(to)
> +# define COPY_PIXEL(to, from)    \
> +    do {                         \
> +        *(uint16_t *) to = from; \
> +        SKIP_PIXEL(to);          \
> +    } while(0)
>  #elif BITS == 24
> -# define COPY_PIXEL(to, from)	\
> -	*(uint16_t *) to = from; *(to + 2) = (from) >> 16; SKIP_PIXEL(to)
> +# define COPY_PIXEL(to, from)     \
> +    do {                          \
> +        *(uint16_t *) to = from;  \
> +        *(to + 2) = (from) >> 16; \
> +        SKIP_PIXEL(to);           \
> +    } while(0)
>  #elif BITS == 32
> -# define COPY_PIXEL(to, from)	*(uint32_t *) to = from; SKIP_PIXEL(to)
> +# define COPY_PIXEL(to, from)    \
> +    do {                         \
> +        *(uint32_t *) to = from; \
> +        SKIP_PIXEL(to);          \
> +    } while(0)
>  #else
>  # error unknown bit depth
>  #endif
> diff --git a/hw/display/tc6393xb_template.h b/hw/display/tc6393xb_template.h
> index 154aafd..964001f 100644
> --- a/hw/display/tc6393xb_template.h
> +++ b/hw/display/tc6393xb_template.h
> @@ -22,14 +22,18 @@
>   */
>  
>  #if BITS == 8
> -# define SET_PIXEL(addr, color)	*(uint8_t*)addr = color;
> +# define SET_PIXEL(addr, color)	*(uint8_t*)addr = color
>  #elif BITS == 15 || BITS == 16
> -# define SET_PIXEL(addr, color)	*(uint16_t*)addr = color;
> +# define SET_PIXEL(addr, color)	*(uint16_t*)addr = color
>  #elif BITS == 24
> -# define SET_PIXEL(addr, color)	\
> -    addr[0] = color; addr[1] = (color) >> 8; addr[2] = (color) >> 16;
> +# define SET_PIXEL(addr, color)  \
> +    do {                         \
> +        addr[0] = color;         \
> +        addr[1] = (color) >> 8;  \
> +        addr[2] = (color) >> 16; \
> +    } while(0)
>  #elif BITS == 32
> -# define SET_PIXEL(addr, color)	*(uint32_t*)addr = color;
> +# define SET_PIXEL(addr, color)	*(uint32_t*)addr = color
>  #else
>  # error unknown bit depth
>  #endif
> 

I kinda have to wash out my eyes now (because of the original code of
course; "*to ++", seriously? :))

Reviewed-by: Laszlo Ersek <lersek@redhat.com>