Mesa (master): i965: Fix partial variable access for geometry shaders in SSO mode.

[Kenneth Graunke]

Module: Mesa
Branch: master
Commit: 9f3917bf372aa19f85875dbe30ca12adc9b67b90
URL:    
http://cgit.freedesktop.org/mesa/mesa/commit/?id=9f3917bf372aa19f85875dbe30ca12adc9b67b90

Author: Kenneth Graunke <kenn...@whitecape.org>
Date:   Wed Dec  9 18:26:19 2015 -0800

i965: Fix partial variable access for geometry shaders in SSO mode.

Without varying packing, if a VS writes a compound variable, and the GS
only reads part of it, the base location of the variable may not
actually be in the VUE map.

To cope with this, we do lowering in terms of varying slots, add any
constant offsets to the base, and then do the VUE map remapping.  This
ensures we only look up VUE map entries for slots which actually exist.

Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
Reviewed-by: Jason Ekstrand <jason.ekstr...@intel.com>

---

 src/mesa/drivers/dri/i965/brw_nir.c |   38 +++++++++++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_nir.c 
b/src/mesa/drivers/dri/i965/brw_nir.c
index c9a2767..88457e4 100644
--- a/src/mesa/drivers/dri/i965/brw_nir.c
+++ b/src/mesa/drivers/dri/i965/brw_nir.c
@@ -114,6 +114,27 @@ remap_vs_attrs(nir_block *block, void *closure)
    return true;
 }
 
+static bool
+remap_inputs_with_vue_map(nir_block *block, void *closure)
+{
+   const struct brw_vue_map *vue_map = closure;
+
+   nir_foreach_instr(block, instr) {
+      if (instr->type != nir_instr_type_intrinsic)
+         continue;
+
+      nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+
+      if (intrin->intrinsic == nir_intrinsic_load_input ||
+          intrin->intrinsic == nir_intrinsic_load_per_vertex_input) {
+         int vue_slot = vue_map->varying_to_slot[intrin->const_index[0]];
+         assert(vue_slot != -1);
+         intrin->const_index[0] = vue_slot;
+      }
+   }
+   return true;
+}
+
 static void
 brw_nir_lower_inputs(nir_shader *nir,
                      const struct brw_device_info *devinfo,
@@ -182,15 +203,24 @@ brw_nir_lower_inputs(nir_shader *nir,
          brw_compute_vue_map(devinfo, &input_vue_map, inputs_read,
                              nir->info.separate_shader);
 
-         /* Start with the slot for the variable's base. */
          foreach_list_typed(nir_variable, var, node, &nir->inputs) {
-            assert(input_vue_map.varying_to_slot[var->data.location] != -1);
-            var->data.driver_location =
-               input_vue_map.varying_to_slot[var->data.location];
+            var->data.driver_location = var->data.location;
          }
 
          /* Inputs are stored in vec4 slots, so use type_size_vec4(). */
          nir_lower_io(nir, nir_var_shader_in, type_size_vec4);
+
+         /* This pass needs actual constants */
+         nir_opt_constant_folding(nir);
+
+         nir_foreach_overload(nir, overload) {
+            if (overload->impl) {
+               nir_builder_init(&params.b, overload->impl);
+               nir_foreach_block(overload->impl, add_const_offset_to_base, 
&params);
+               nir_foreach_block(overload->impl, remap_inputs_with_vue_map,
+                                 &input_vue_map);
+            }
+         }
       }
       break;
    }

_______________________________________________
mesa-commit mailing list
mesa-commit@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-commit