[Mesa-dev] [PATCH] draw: fix key comparison with uninitialized value

[sroland at vmware.com]

From: Roland Scheidegger <sroland at vmware.com>

Discovered by accident, valgrind was complaining (could have possibly caused
us to create redundant geometry shader variants).

v2: convinced by Brian and Jose, just use memset for both gs and vs keys,
just as easy and less error prone.
---
 src/gallium/auxiliary/draw/draw_llvm.c | 5 ++++-
 src/gallium/auxiliary/draw/draw_llvm.h | 7 ++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/gallium/auxiliary/draw/draw_llvm.c b/src/gallium/auxiliary/draw/draw_llvm.c
index f25dafe..142d78a 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.c
+++ b/src/gallium/auxiliary/draw/draw_llvm.c
@@ -1861,6 +1861,8 @@ draw_llvm_make_variant_key(struct draw_llvm *llvm, char *store)
 
    key = (struct draw_llvm_variant_key *)store;
 
+   memset(key, 0, offsetof(struct draw_llvm_variant_key, vertex_element[0]));
+
    key->clamp_vertex_color = llvm->draw->rasterizer->clamp_vertex_color; /**/
 
    /* Presumably all variants of the shader should have the same
@@ -1883,7 +1885,6 @@ draw_llvm_make_variant_key(struct draw_llvm *llvm, char *store)
    key->ucp_enable = llvm->draw->rasterizer->clip_plane_enable;
    key->has_gs = llvm->draw->gs.geometry_shader != NULL;
    key->num_outputs = draw_total_vs_outputs(llvm->draw);
-   key->pad1 = 0;
 
    /* All variants of this shader will have the same value for
     * nr_samplers.  Not yet trying to compact away holes in the
@@ -2315,6 +2316,8 @@ draw_gs_llvm_make_variant_key(struct draw_llvm *llvm, char *store)
 
    key = (struct draw_gs_llvm_variant_key *)store;
 
+   memset(key, 0, offsetof(struct draw_gs_llvm_variant_key, samplers[0]));
+
    key->num_outputs = draw_total_gs_outputs(llvm->draw);
 
    /* All variants of this shader will have the same value for
diff --git a/src/gallium/auxiliary/draw/draw_llvm.h b/src/gallium/auxiliary/draw/draw_llvm.h
index f617a29..271433c 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.h
+++ b/src/gallium/auxiliary/draw/draw_llvm.h
@@ -311,12 +311,8 @@ struct draw_llvm_variant_key
    unsigned need_edgeflags:1;
    unsigned has_gs:1;
    unsigned num_outputs:8;
-   /*
-    * it is important there are no holes in this struct
-    * (and all padding gets zeroed).
-    */
    unsigned ucp_enable:PIPE_MAX_CLIP_PLANES;
-   unsigned pad1:24-PIPE_MAX_CLIP_PLANES;
+   /* note padding here - must use memset */
 
    /* Variable number of vertex elements:
     */
@@ -332,6 +328,7 @@ struct draw_gs_llvm_variant_key
    unsigned nr_samplers:8;
    unsigned nr_sampler_views:8;
    unsigned num_outputs:8;
+   /* note padding here - must use memset */
 
    struct draw_sampler_static_state samplers[1];
 };
-- 
2.1.4