[Mesa-dev] [PATCH] radeonsi: Fix crash on shaders using MSAA image load/store

[Alex Smith]

The value returned by tgsi_util_get_texture_coord_dim() does not
account for the sample index. This means image_fetch_coords() will not
fetch it, leading to a null deref in ac_build_image_opcode() which
expects it to be present (the return value of ac_num_coords() *does*
include the sample index).

Signed-off-by: Alex Smith <asmith at feralinteractive.com>
Cc: "18.1" <mesa-stable at lists.freedesktop.org>
---
 src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c b/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c
index 1c244fa3c0..d0dd4e7cab 100644
--- a/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c
+++ b/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c
@@ -276,10 +276,16 @@ static void image_fetch_coords(
 	struct si_shader_context *ctx = si_shader_context(bld_base);
 	LLVMBuilderRef builder = ctx->ac.builder;
 	unsigned target = inst->Memory.Texture;
-	const unsigned num_coords = tgsi_util_get_texture_coord_dim(target);
+	unsigned num_coords = tgsi_util_get_texture_coord_dim(target);
 	LLVMValueRef tmp;
 	int chan;
 
+	if (target == TGSI_TEXTURE_2D_MSAA ||
+	    target == TGSI_TEXTURE_2D_ARRAY_MSAA) {
+		/* Need the sample index as well. */
+		num_coords++;
+	}
+
 	for (chan = 0; chan < num_coords; ++chan) {
 		tmp = lp_build_emit_fetch(bld_base, inst, src, chan);
 		tmp = ac_to_integer(&ctx->ac, tmp);
-- 
2.14.3