[Mesa-dev] [PATCH] i965: delay adding built-in uniforms to Parameters list

[Timothy Arceri]

This is a step towards using NIR optimisations over GLSL IR
optimisations. Delaying adding built-in uniforms until after
we convert to NIR gives it a chance to optimise them away.
---
 src/mesa/drivers/dri/i965/brw_link.cpp  | 23 -----------------------
 src/mesa/drivers/dri/i965/brw_program.c | 19 +++++++++++++++++++
 2 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_link.cpp b/src/mesa/drivers/dri/i965/brw_link.cpp
index 3f6041b..1d0a85b 100644
--- a/src/mesa/drivers/dri/i965/brw_link.cpp
+++ b/src/mesa/drivers/dri/i965/brw_link.cpp
@@ -228,29 +228,6 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
 
       _mesa_copy_linked_program_data(shProg, shader);
 
-      /* Make a pass over the IR to add state references for any built-in
-       * uniforms that are used.  This has to be done now (during linking).
-       * Code generation doesn't happen until the first time this shader is
-       * used for rendering.  Waiting until then to generate the parameters is
-       * too late.  At that point, the values for the built-in uniforms won't
-       * get sent to the shader.
-       */
-      foreach_in_list(ir_instruction, node, shader->ir) {
-         ir_variable *var = node->as_variable();
-
-         if ((var == NULL) || (var->data.mode != ir_var_uniform)
-             || (strncmp(var->name, "gl_", 3) != 0))
-            continue;
-
-         const ir_state_slot *const slots = var->get_state_slots();
-         assert(slots != NULL);
-
-         for (unsigned int i = 0; i < var->get_num_state_slots(); i++) {
-            _mesa_add_state_reference(prog->Parameters,
-                                      (gl_state_index *) slots[i].tokens);
-         }
-      }
-
       prog->SamplersUsed = shader->active_samplers;
       prog->ShadowSamplers = shader->shadow_samplers;
       _mesa_update_shader_textures_used(shProg, prog);
diff --git a/src/mesa/drivers/dri/i965/brw_program.c b/src/mesa/drivers/dri/i965/brw_program.c
index a502b8e..cc7ec94 100644
--- a/src/mesa/drivers/dri/i965/brw_program.c
+++ b/src/mesa/drivers/dri/i965/brw_program.c
@@ -90,6 +90,25 @@ brw_create_nir(struct brw_context *brw,
 
    nir = brw_preprocess_nir(brw->screen->compiler, nir);
 
+   /* Make a pass over the IR to add state references for any built-in
+    * uniforms that are used.  This has to be done now (during linking).
+    * Code generation doesn't happen until the first time this shader is
+    * used for rendering.  Waiting until then to generate the parameters is
+    * too late.  At that point, the values for the built-in uniforms won't
+    * get sent to the shader.
+    */
+   nir_foreach_variable(var, &nir->uniforms) {
+      if (strncmp(var->name, "gl_", 3) == 0) {
+         const nir_state_slot *const slots = var->state_slots;
+         assert(var->state_slots != NULL);
+
+         for (unsigned int i = 0; i < var->num_state_slots; i++) {
+            _mesa_add_state_reference(prog->Parameters,
+                                      (gl_state_index *)slots[i].tokens);
+         }
+      }
+   }
+
    if (stage == MESA_SHADER_FRAGMENT) {
       static const struct nir_lower_wpos_ytransform_options wpos_options = {
          .state_tokens = {STATE_INTERNAL, STATE_FB_WPOS_Y_TRANSFORM, 0, 0, 0},
-- 
2.7.4