[cairo] slow path annotations

[Behdad Esfahbod]

On Thu, 2007-03-08 at 11:37 -0500, Jeff Muizelaar wrote:
> The following patch annotates some of the slow paths in cairo with
> cairo_slow_path() or pixman_slow_path() as appropriate. If either of
> these functions is called, cairo will raise a SIGTRAP. 

Great stuff for the debugging mode.  Lets focus on some bugfixing for a
bit, probably get 1.4.2 out, then start adding debug options and
reworking the test suite.

And we should raise SIGTRAP in cairo_error() too btw!  Maybe by default
even.  Comments?


> Note, X has the pretty much the same slow paths as pixman, however this
> patch will not catch them. You can fix this by rending to a temporary
> image surface and then set_source'ing and painting to your X cairo
> context.

Some of them checks you can do before calling xlib, right?

Thanks
behdad

> -Jeff
> 
> diff --git a/pixman/src/fbcompose.c b/pixman/src/fbcompose.c
> index 233b90c..8f5cb87 100644
> --- a/pixman/src/fbcompose.c
> +++ b/pixman/src/fbcompose.c
> @@ -4206,6 +4206,10 @@ pixman_compositeGeneral (pixman_operator_t	op,
>      CARD32 *scanline_buffer = _scanline_buffer;
>      FbComposeData compose_data;
>  
> +    /* Don't treat gradients as a slow path because there is no fast path */
> +    if (pSrc->pDrawable)
> +	    pixman_slow_path();
> +
>      if (pSrc->pDrawable)
>          srcRepeat = pSrc->repeat == RepeatNormal && !pSrc->transform
>                      && (pSrc->pDrawable->width != 1 || pSrc->pDrawable->height != 1);
> diff --git a/pixman/src/fbpict.c b/pixman/src/fbpict.c
> index 0bd989f..af3ff26 100644
> --- a/pixman/src/fbpict.c
> +++ b/pixman/src/fbpict.c
> @@ -1951,6 +1951,14 @@ pixman_composite (pixman_operator_t	op,
>  
>      n = pixman_region_num_rects (region);
>      pbox = pixman_region_rects (region);
> +
> +    /* check for compositing a solid surface without a solid varient */
> +    if (srcRepeat && pSrc->pDrawable &&
> +		    pSrc->pDrawable->height == 1 &&
> +		    pSrc->pDrawable->width == 1 &&
> +		    (pbox->y2 - pbox->y1 > 1 || pbox->x2 - pbox->x1 > 1))
> +	    pixman_slow_path();
> +
>      while (n--)
>      {
>  	h = pbox->y2 - pbox->y1;
> diff --git a/pixman/src/icint.h b/pixman/src/icint.h
> index 47a2220..46cf955 100644
> --- a/pixman/src/icint.h
> +++ b/pixman/src/icint.h
> @@ -117,6 +117,12 @@ typedef pixman_triangle_t	xTriangle;
>  #define MAXSHORT SHRT_MAX
>  #define MINSHORT SHRT_MIN
>  
> +#include <signal.h>
> +static inline void pixman_slow_path(void)
> +{
> +	raise(5);
> +}
> +
>  /* XXX: What do we need from here?
>  #include "picture.h"
>  */
> diff --git a/src/cairo-surface-fallback.c b/src/cairo-surface-fallback.c
> index 1a7d666..3a0cf0f 100644
> --- a/src/cairo-surface-fallback.c
> +++ b/src/cairo-surface-fallback.c
> @@ -284,14 +284,15 @@ _clip_and_composite_source (cairo_clip_t                  *clip,
>      cairo_surface_pattern_t mask_pattern;
>      cairo_status_t status;
>  
> +    /* Single composite operation becomes two.
> +     * Two, that are likely not fast */
> +    /* If you hit this maybe you should be using OVER instead of SOURCE */
> +    cairo_slow_path();
> +
>      /* Create a surface that is mask IN clip
>       */
> -    status = _create_composite_mask_pattern (&mask_pattern,
> -					     clip,
> -					     draw_func, draw_closure,
> -					     dst, extents);
> -    if (status)
> -	return status;
> +    status = _create_composite_mask_pattern (&mask_pattern, clip, draw_func,
> +		    draw_closure, dst, extents); if (status) return status;
>  
>      /* Compute dest' = dest OUT (mask IN clip)
>       */
> diff --git a/src/cairoint.h b/src/cairoint.h
> index 19897ff..4ccea82 100755
> --- a/src/cairoint.h
> +++ b/src/cairoint.h
> @@ -272,6 +272,12 @@ typedef cairo_fixed_16_16_t cairo_fixed_t;
>  #define CAIRO_BITSWAP8_IF_LITTLE_ENDIAN(c) CAIRO_BITSWAP8(c)
>  #endif
>  
> +#include <signal.h>
> +static inline void cairo_slow_path(void)
> +{
> +	raise(5);
> +}
> +
>  #include "cairo-hash-private.h"
>  #include "cairo-cache-private.h"
>  
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-- 
behdad
http://behdad.org/

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