glsl: Add glsl LowerCsDerivedVariables option

v2:
 * Move lower flag to context constants. (Ken)

Cc: "12.0" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> (v1)
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

3 files changed, 21 insertions, 13 deletions

diff --git a/src/compiler/glsl/builtin_variables.cpp b/src/compiler/glsl/builtin_variables.cpp
index 401c713..05b3b0b 100644
--- a/src/compiler/glsl/builtin_variables.cpp
+++ b/src/compiler/glsl/builtin_variables.cpp
@@ -1201,8 +1201,15 @@ builtin_variable_generator::generate_cs_special_vars()
                     "gl_LocalInvocationID");
    add_system_value(SYSTEM_VALUE_WORK_GROUP_ID, uvec3_t, "gl_WorkGroupID");
    add_system_value(SYSTEM_VALUE_NUM_WORK_GROUPS, uvec3_t, "gl_NumWorkGroups");
-   add_variable("gl_GlobalInvocationID", uvec3_t, ir_var_auto, 0);
-   add_variable("gl_LocalInvocationIndex", uint_t, ir_var_auto, 0);
+   if (state->ctx->Const.LowerCsDerivedVariables) {
+      add_variable("gl_GlobalInvocationID", uvec3_t, ir_var_auto, 0);
+      add_variable("gl_LocalInvocationIndex", uint_t, ir_var_auto, 0);
+   } else {
+      add_system_value(SYSTEM_VALUE_GLOBAL_INVOCATION_ID,
+                       uvec3_t, "gl_GlobalInvocationID");
+      add_system_value(SYSTEM_VALUE_LOCAL_INVOCATION_INDEX,
+                       uint_t, "gl_LocalInvocationIndex");
+   }
 }
 
 
@@ -1431,16 +1438,16 @@ initialize_cs_derived_variables(gl_shader *shader,
  * These are initialized in the main function.
  */
 void
-_mesa_glsl_initialize_derived_variables(gl_shader *shader)
+_mesa_glsl_initialize_derived_variables(struct gl_context *ctx,
+                                        gl_shader *shader)
 {
    /* We only need to set CS variables currently. */
-   if (shader->Stage != MESA_SHADER_COMPUTE)
-      return;
+   if (shader->Stage == MESA_SHADER_COMPUTE &&
+       ctx->Const.LowerCsDerivedVariables) {
+      ir_function_signature *const main_sig =
+         _mesa_get_main_function_signature(shader);
 
-   ir_function_signature *const main_sig =
-      _mesa_get_main_function_signature(shader);
-   if (main_sig == NULL)
-      return;
-
-   initialize_cs_derived_variables(shader, main_sig);
+      if (main_sig != NULL)
+         initialize_cs_derived_variables(shader, main_sig);
+   }
 }
diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
index 2e3395e..c9654ac 100644
--- a/src/compiler/glsl/glsl_parser_extras.cpp
+++ b/src/compiler/glsl/glsl_parser_extras.cpp
@@ -1907,7 +1907,7 @@ _mesa_glsl_compile_shader(struct gl_context *ctx, struct gl_shader *shader,
       }
    }
 
-   _mesa_glsl_initialize_derived_variables(shader);
+   _mesa_glsl_initialize_derived_variables(ctx, shader);
 
    delete state->symbols;
    ralloc_free(state);
diff --git a/src/compiler/glsl/ir.h b/src/compiler/glsl/ir.h
index e8efd27..93716c4 100644
--- a/src/compiler/glsl/ir.h
+++ b/src/compiler/glsl/ir.h
@@ -2562,7 +2562,8 @@ _mesa_glsl_initialize_variables(exec_list *instructions,
 				struct _mesa_glsl_parse_state *state);
 
 extern void
-_mesa_glsl_initialize_derived_variables(gl_shader *shader);
+_mesa_glsl_initialize_derived_variables(struct gl_context *ctx,
+                                        gl_shader *shader);
 
 extern void
 _mesa_glsl_initialize_functions(_mesa_glsl_parse_state *state);