i965: Fix component mask and varying_to_slot mapping for gl_Layer

gl_Layer doesn't get its own varying slot. It is stored in
VARYING_SLOT_PSIZ.y. This patch fixes the issue for both gen7
and gen8 because gen7_upload_3dstate_so_decl_list() is shared
between them.

Fixes failures in OpenGL Khronos CTS test transform_feedback_builtins.
Makes new piglit test glsl-1.50-transform-feedback-builtins pass for
'gl_Layer'.

Cc: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/mesa/drivers/dri/i965/gen7_sol_state.c b/src/mesa/drivers/dri/i965/gen7_sol_state.c
index 06a4cdf36c9cc846d3106ebb8ee58318c0702dfe..3623238d3f69a586fda111773743758523be406d 100644 (file)
--- a/src/mesa/drivers/dri/i965/gen7_sol_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_sol_state.c
@@ -121,10 +121,15 @@ gen7_upload_3dstate_so_decl_list(struct brw_context *brw,
       const unsigned components = linked_xfb_info->Outputs[i].NumComponents;
       unsigned component_mask = (1 << components) - 1;
 
-      /* gl_PointSize is stored in VARYING_SLOT_PSIZ.w. */
+      /* gl_PointSize is stored in VARYING_SLOT_PSIZ.w
+       * gl_Layer is stored in VARYING_SLOT_PSIZ.y
+       */
       if (varying == VARYING_SLOT_PSIZ) {
          assert(components == 1);
          component_mask <<= 3;
+      } else if (varying == VARYING_SLOT_LAYER) {
+         assert(components == 1);
+         component_mask <<= 1;
       } else {
          component_mask <<= linked_xfb_info->Outputs[i].ComponentOffset;
       }
@@ -132,9 +137,14 @@ gen7_upload_3dstate_so_decl_list(struct brw_context *brw,
       buffer_mask |= 1 << buffer;
 
       decl |= buffer << SO_DECL_OUTPUT_BUFFER_SLOT_SHIFT;
-      assert(vue_map->varying_to_slot[varying] >= 0);
-      decl |= vue_map->varying_to_slot[varying] <<
-        SO_DECL_REGISTER_INDEX_SHIFT;
+      if (varying == VARYING_SLOT_LAYER) {
+         decl |= vue_map->varying_to_slot[VARYING_SLOT_PSIZ] <<
+            SO_DECL_REGISTER_INDEX_SHIFT;
+      } else {
+         assert(vue_map->varying_to_slot[varying] >= 0);
+         decl |= vue_map->varying_to_slot[varying] <<
+            SO_DECL_REGISTER_INDEX_SHIFT;
+      }
       decl |= component_mask << SO_DECL_COMPONENT_MASK_SHIFT;
 
       /* Mesa doesn't store entries for gl_SkipComponents in the Outputs[]