Mesa (master): i965: Move SOL PSIZ hacks from draw time to link time.

[Kenneth Graunke]

Module: Mesa
Branch: master
Commit: 65f5f3c85c5303c88c6dddbb435ad6aa0ebfce5f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=65f5f3c85c5303c88c6dddbb435ad6aa0ebfce5f

Author: Kenneth Graunke <kenneth at whitecape.org>
Date:   Tue Feb 28 12:29:43 2017 -0800

i965: Move SOL PSIZ hacks from draw time to link time.

We can just update the gl_transform_feedback_info fields at link time
to make the VUE header fields have the right location and component.
Then we don't need to handle them specially at draw time, which is
expensive.

Reviewed-by: Rafael Antognolli <rafael.antognolli at intel.com>

---

 src/intel/compiler/gen6_gs_visitor.cpp        | 13 +---------
 src/mesa/drivers/dri/i965/brw_link.cpp        | 36 +++++++++++++++++++++++++++
 src/mesa/drivers/dri/i965/genX_state_upload.c | 26 +++----------------
 3 files changed, 41 insertions(+), 34 deletions(-)

diff --git a/src/intel/compiler/gen6_gs_visitor.cpp b/src/intel/compiler/gen6_gs_visitor.cpp
index fe9f834f0c..66c69fb058 100644
--- a/src/intel/compiler/gen6_gs_visitor.cpp
+++ b/src/intel/compiler/gen6_gs_visitor.cpp
@@ -687,18 +687,7 @@ gen6_gs_visitor::xfb_program(unsigned vertex, unsigned num_verts)
          emit(MOV(dst_reg(this->vertex_output_offset), brw_imm_d(offset)));
          memcpy(data.reladdr, &this->vertex_output_offset, sizeof(src_reg));
          data.type = output_reg[varying][0].type;
-
-         /* PSIZ, LAYER and VIEWPORT are packed in different channels of the
-          * same slot, so make sure we write the appropriate channel
-          */
-         if (varying == VARYING_SLOT_PSIZ)
-            data.swizzle = BRW_SWIZZLE_WWWW;
-         else if (varying == VARYING_SLOT_LAYER)
-            data.swizzle = BRW_SWIZZLE_YYYY;
-         else if (varying == VARYING_SLOT_VIEWPORT)
-            data.swizzle = BRW_SWIZZLE_ZZZZ;
-         else
-            data.swizzle = gs_prog_data->transform_feedback_swizzles[binding];
+         data.swizzle = gs_prog_data->transform_feedback_swizzles[binding];
 
          /* Write data */
          inst = emit(GS_OPCODE_SVB_WRITE, mrf_reg, data, sol_temp);
diff --git a/src/mesa/drivers/dri/i965/brw_link.cpp b/src/mesa/drivers/dri/i965/brw_link.cpp
index 57aaf6b9dc..e9158c596c 100644
--- a/src/mesa/drivers/dri/i965/brw_link.cpp
+++ b/src/mesa/drivers/dri/i965/brw_link.cpp
@@ -28,6 +28,7 @@
 #include "compiler/glsl/ir_optimization.h"
 #include "compiler/glsl/program.h"
 #include "program/program.h"
+#include "main/mtypes.h"
 #include "main/shaderapi.h"
 #include "main/shaderobj.h"
 #include "main/uniforms.h"
@@ -176,6 +177,39 @@ unify_interfaces(struct shader_info **infos)
    }
 }
 
+static void
+update_xfb_info(struct gl_transform_feedback_info *xfb_info)
+{
+   if (!xfb_info)
+      return;
+
+   for (unsigned i = 0; i < xfb_info->NumOutputs; i++) {
+      struct gl_transform_feedback_output *output = &xfb_info->Outputs[i];
+
+      /* The VUE header contains three scalar fields packed together:
+       * - gl_PointSize is stored in VARYING_SLOT_PSIZ.w
+       * - gl_Layer is stored in VARYING_SLOT_PSIZ.y
+       * - gl_ViewportIndex is stored in VARYING_SLOT_PSIZ.z
+       */
+      switch (output->OutputRegister) {
+      case VARYING_SLOT_LAYER:
+         assert(output->NumComponents == 1);
+         output->OutputRegister = VARYING_SLOT_PSIZ;
+         output->ComponentOffset = 1;
+         break;
+      case VARYING_SLOT_VIEWPORT:
+         assert(output->NumComponents == 1);
+         output->OutputRegister = VARYING_SLOT_PSIZ;
+         output->ComponentOffset = 2;
+         break;
+      case VARYING_SLOT_PSIZ:
+         assert(output->NumComponents == 1);
+         output->ComponentOffset = 3;
+         break;
+      }
+   }
+}
+
 extern "C" GLboolean
 brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
 {
@@ -199,6 +233,8 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
       prog->ShadowSamplers = shader->shadow_samplers;
       _mesa_update_shader_textures_used(shProg, prog);
 
+      update_xfb_info(prog->sh.LinkedTransformFeedback);
+
       bool debug_enabled =
          (INTEL_DEBUG & intel_debug_flag_for_shader_stage(shader->Stage));
 
diff --git a/src/mesa/drivers/dri/i965/genX_state_upload.c b/src/mesa/drivers/dri/i965/genX_state_upload.c
index 76d2ea887b..a2ed2e7271 100644
--- a/src/mesa/drivers/dri/i965/genX_state_upload.c
+++ b/src/mesa/drivers/dri/i965/genX_state_upload.c
@@ -3087,32 +3087,14 @@ genX(upload_3dstate_so_decl_list)(struct brw_context *brw,
       unsigned decl_buffer_slot = buffer;
       assert(stream_id < MAX_VERTEX_STREAMS);
 
-      /* gl_PointSize is stored in VARYING_SLOT_PSIZ.w
-       * gl_Layer is stored in VARYING_SLOT_PSIZ.y
-       * gl_ViewportIndex is stored in VARYING_SLOT_PSIZ.z
-       */
-      if (varying == VARYING_SLOT_PSIZ) {
-         assert(components == 1);
-         component_mask <<= 3;
-      } else if (varying == VARYING_SLOT_LAYER) {
-         assert(components == 1);
-         component_mask <<= 1;
-      } else if (varying == VARYING_SLOT_VIEWPORT) {
-         assert(components == 1);
-         component_mask <<= 2;
-      } else {
-         component_mask <<= linked_xfb_info->Outputs[i].ComponentOffset;
-      }
+      component_mask <<= linked_xfb_info->Outputs[i].ComponentOffset;
 
       buffer_mask[stream_id] |= 1 << buffer;
 
+      assert(vue_map->varying_to_slot[varying] >= 0);
+
       decl.OutputBufferSlot = decl_buffer_slot;
-      if (varying == VARYING_SLOT_LAYER || varying == VARYING_SLOT_VIEWPORT) {
-         decl.RegisterIndex = vue_map->varying_to_slot[VARYING_SLOT_PSIZ];
-      } else {
-         assert(vue_map->varying_to_slot[varying] >= 0);
-         decl.RegisterIndex = vue_map->varying_to_slot[varying];
-      }
+      decl.RegisterIndex = vue_map->varying_to_slot[varying];
       decl.ComponentMask = component_mask;
 
       /* Mesa doesn't store entries for gl_SkipComponents in the Outputs[]