Mesa (master): draw: correctly handle max_index= 0xffffffff case in vcache code
Brian Paul
brianp at kemper.freedesktop.org
Tue Jul 20 17:54:03 UTC 2010
Module: Mesa
Branch: master
Commit: 691c1fb074144395aa441b3102923d8f92136c37
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=691c1fb074144395aa441b3102923d8f92136c37
Author: Brian Paul <brianp at vmware.com>
Date: Tue Jul 20 11:46:43 2010 -0600
draw: correctly handle max_index=0xffffffff case in vcache code
If max_index=0xffffffff and elt_bias > 0 the test for
elt_bias + max_index >= DRAW_PIPE_MAX_VERTICES
was wrong. Check earlier if max_index=0xffffffff and do the
"fail" case.
This fixes the piglit draw-elements-base-vertex test (and probably
some other things).
---
src/gallium/auxiliary/draw/draw_pt_vcache.c | 20 ++++++++++++++------
1 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/src/gallium/auxiliary/draw/draw_pt_vcache.c b/src/gallium/auxiliary/draw/draw_pt_vcache.c
index d856bd8..e9b2a3a 100644
--- a/src/gallium/auxiliary/draw/draw_pt_vcache.c
+++ b/src/gallium/auxiliary/draw/draw_pt_vcache.c
@@ -347,16 +347,11 @@ vcache_check_run( struct draw_pt_front_end *frontend,
const unsigned min_index = draw->pt.user.min_index;
const unsigned max_index = draw->pt.user.max_index;
const unsigned index_size = draw->pt.user.eltSize;
- const unsigned fetch_count = max_index + 1 - min_index;
+ unsigned fetch_count;
const ushort *transformed_elts;
ushort *storage = NULL;
boolean ok = FALSE;
-
- if (0) debug_printf("fetch_count %d fetch_max %d draw_count %d\n", fetch_count,
- vcache->fetch_max,
- draw_count);
-
/* debug: verify indexes are in range [min_index, max_index] */
if (0) {
unsigned i;
@@ -377,6 +372,19 @@ vcache_check_run( struct draw_pt_front_end *frontend,
}
}
+ /* Note: max_index is frequently 0xffffffff so we have to be sure
+ * that any arithmetic involving max_index doesn't overflow!
+ */
+ if (max_index >= (unsigned) DRAW_PIPE_MAX_VERTICES)
+ goto fail;
+
+ fetch_count = max_index + 1 - min_index;
+
+ if (0)
+ debug_printf("fetch_count %d fetch_max %d draw_count %d\n", fetch_count,
+ vcache->fetch_max,
+ draw_count);
+
if (elt_bias + max_index >= DRAW_PIPE_MAX_VERTICES ||
fetch_count >= UNDEFINED_VERTEX_ID ||
fetch_count > draw_count) {
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