[Mesa-dev] [PATCH 01/18] t_dd_dmatmp: Replace fprintf with unreachable

[Iago Toral]

On Wed, 2015-09-30 at 13:57 -0700, Ian Romanick wrote:
> From: Ian Romanick <ian.d.romanick at intel.com>
> 
> From http://lists.freedesktop.org/archives/mesa-dev/2015-May/084883.html:
> 
>     "There are no real error cases here, just dead code.
>     validate_render() is supposed to make sure we never call these
>     functions if the code can't actually render the primitives. The
>     fprintf()+return branches should really just contain assert(0) or
>     equivalent."
> 
> I also rearranged the if-else-block in render_quad_strip_verts to look
> more like the other functions.  A future patch is going to change a
> bunch of that code anyway.
> 
> Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
> Suggested-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  src/mesa/tnl_dd/t_dd_dmatmp.h | 18 ++++++------------
>  1 file changed, 6 insertions(+), 12 deletions(-)
> 
> diff --git a/src/mesa/tnl_dd/t_dd_dmatmp.h b/src/mesa/tnl_dd/t_dd_dmatmp.h
> index e7e19a0..415c3df 100644
> --- a/src/mesa/tnl_dd/t_dd_dmatmp.h
> +++ b/src/mesa/tnl_dd/t_dd_dmatmp.h
> @@ -85,8 +85,7 @@ static void TAG(render_points_verts)(struct gl_context *ctx,
>           currentsz = dmasz;
>        }
>     } else {
> -      fprintf(stderr, "%s - cannot draw primitive\n", __func__);
> -      return;
> +      unreachable("Cannot draw primitive");

Since the reason this is unreachable is because a previous call to
validate_render should have prevented this, maybe it would be better to
modify the message to mention that explicitly, something like:

unreachable("Cannot draw primitive; validate_render should have
prevented this");

>     }
>  }
>  
> @@ -319,8 +318,7 @@ static void TAG(render_poly_verts)(struct gl_context *ctx,
>     } else if (ctx->Light.ShadeModel == GL_SMOOTH) {
>        TAG(render_tri_fan_verts)( ctx, start, count, flags );
>     } else {
> -      fprintf(stderr, "%s - cannot draw primitive\n", __func__);
> -      return;
> +      unreachable("Cannot draw primitive");

Same here

>     }
>  }
>  
> @@ -331,14 +329,8 @@ static void TAG(render_quad_strip_verts)(struct gl_context *ctx,
>  {
>     GLuint j, nr;
>  
> -   if (ctx->Light.ShadeModel == GL_FLAT &&
> -       TNL_CONTEXT(ctx)->vb.AttribPtr[_TNL_ATTRIB_COLOR0]->stride) {
> -      /* Vertices won't fit in a single buffer or elts not available - should
> -       * never happen.
> -       */
> -      fprintf(stderr, "%s - cannot draw primitive\n", __func__);
> -      return;

Same here

> -   } else {
> +   if (ctx->Light.ShadeModel != GL_FLAT ||
> +       !TNL_CONTEXT(ctx)->vb.AttribPtr[_TNL_ATTRIB_COLOR0]->stride) {
>        LOCAL_VARS;
>        const unsigned dmasz = GET_SUBSEQUENT_VB_MAX_VERTS() & ~1;
>        unsigned currentsz;
> @@ -364,6 +356,8 @@ static void TAG(render_quad_strip_verts)(struct gl_context *ctx,
>        }
>  
>        FLUSH();
> +   } else {
> +      unreachable("Cannot draw primitive");

Same here

Otherwise:

Reviewed-by: Iago Toral Quiroga <itoral at igalia.com>

>     }
>  }
>