[Mesa-dev] [PATCH] gallivm: fix up out-of-bounds level when using conformant out-of-bound behavior

[sroland at vmware.com]

From: Roland Scheidegger <sroland at vmware.com>

When using (d3d10) conformant out-of-bound behavior for texel fetching
(currently always enabled) the level still needs to be set to a safe value
even though the offset in the end won't get used because the level is used
to look up the mip offset itself and the actual strides, which might otherwise
crash.
For simplicity, we'll use level 0 in this case (this ought to be safe, llvmpipe
does not actually fill in level 0 information if first_level is larger, but
some random strides / offsets shouldn't hurt as ultimately we always use
offset 0 in this case).
Fixes a crash in some in-house test where random huge levels appear in
lp_build_fetch_texel() despite the test always using a fixed 0 for level
actually... But in any case the value comes from the shader and thus can
easily be outside max mip level.

CC: <mesa-stable at lists.freedesktop.org>
---
 src/gallium/auxiliary/gallivm/lp_bld_sample.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_sample.c b/src/gallium/auxiliary/gallivm/lp_bld_sample.c
index aeecba8..f1bf285 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_sample.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_sample.c
@@ -927,6 +927,7 @@ lp_build_nearest_mip_level(struct lp_build_sample_context *bld,
                                                                 bld->int_coord_bld.type,
                                                                 out);
       }
+      level = lp_build_andnot(&bld->int_coord_bld, level, *out_of_bounds);
       *level_out = level;
    }
    else {
-- 
1.9.1