[Mesa-dev] [PATCH V3 16/28] glsl: add packing rules for tessellation stages to the packing code

[Timothy Arceri]

Following patches will allow packing of varyings with explicit locations
via the component layout qualifier. Adding the rules here will enable
us to call an alternate path for packing tessellation stages with
explicit locations.

V3: Don't remove rules from the varying linking code as we need to
disable packing in the producer if the consumer is a TCS.

V2: move the tessellation packing rules, allow TES output to be packed.

Cc: Anuj Phogat <anuj.phogat at gmail.com>
---
 src/compiler/glsl/lower_packed_varyings.cpp | 63 ++++++++++++++++-------------
 1 file changed, 35 insertions(+), 28 deletions(-)

diff --git a/src/compiler/glsl/lower_packed_varyings.cpp b/src/compiler/glsl/lower_packed_varyings.cpp
index 2899846..4723c2b 100644
--- a/src/compiler/glsl/lower_packed_varyings.cpp
+++ b/src/compiler/glsl/lower_packed_varyings.cpp
@@ -737,40 +737,47 @@ lower_packed_varyings(void *mem_ctx, unsigned locations_used,
                       ir_variable_mode mode, unsigned gs_input_vertices,
                       gl_shader *shader, bool disable_varying_packing)
 {
-   exec_list *instructions = shader->ir;
    ir_function *main_func = shader->symbols->get_function("main");
    exec_list void_parameters;
    ir_function_signature *main_func_sig
       = main_func->matching_signature(NULL, &void_parameters, false);
-   exec_list new_instructions, new_variables;
-   lower_packed_varyings_visitor visitor(mem_ctx, locations_used, mode,
-                                         gs_input_vertices,
-                                         &new_instructions,
-                                         &new_variables,
-                                         disable_varying_packing);
-   visitor.run(shader);
-   if (mode == ir_var_shader_out) {
-      if (shader->Stage == MESA_SHADER_GEOMETRY) {
-         /* For geometry shaders, outputs need to be lowered before each call
-          * to EmitVertex()
-          */
-         lower_packed_varyings_gs_splicer splicer(mem_ctx, &new_instructions);
-
-         /* Add all the variables in first. */
-         main_func_sig->body.head->insert_before(&new_variables);
 
-         /* Now update all the EmitVertex instances */
-         splicer.run(instructions);
+   if (!(shader->Stage == MESA_SHADER_TESS_CTRL ||
+         (shader->Stage == MESA_SHADER_TESS_EVAL &&
+          mode == ir_var_shader_in))) {
+      exec_list *instructions = shader->ir;
+      exec_list new_instructions, new_variables;
+
+      lower_packed_varyings_visitor visitor(mem_ctx, locations_used, mode,
+                                            gs_input_vertices,
+                                            &new_instructions,
+                                            &new_variables,
+                                            disable_varying_packing);
+      visitor.run(shader);
+      if (mode == ir_var_shader_out) {
+         if (shader->Stage == MESA_SHADER_GEOMETRY) {
+            /* For geometry shaders, outputs need to be lowered before each
+             * call to EmitVertex()
+             */
+            lower_packed_varyings_gs_splicer splicer(mem_ctx,
+                                                     &new_instructions);
+
+            /* Add all the variables in first. */
+            main_func_sig->body.head->insert_before(&new_variables);
+
+            /* Now update all the EmitVertex instances */
+            splicer.run(instructions);
+         } else {
+            /* For other shader types, outputs need to be lowered at the end
+             * of main()
+             */
+            main_func_sig->body.append_list(&new_variables);
+            main_func_sig->body.append_list(&new_instructions);
+         }
       } else {
-         /* For other shader types, outputs need to be lowered at the end of
-          * main()
-          */
-         main_func_sig->body.append_list(&new_variables);
-         main_func_sig->body.append_list(&new_instructions);
+         /* Shader inputs need to be lowered at the beginning of main() */
+         main_func_sig->body.head->insert_before(&new_instructions);
+         main_func_sig->body.head->insert_before(&new_variables);
       }
-   } else {
-      /* Shader inputs need to be lowered at the beginning of main() */
-      main_func_sig->body.head->insert_before(&new_instructions);
-      main_func_sig->body.head->insert_before(&new_variables);
    }
 }
-- 
2.5.0