nir: Set .driver_location for GLSL UBO/SSBOs when we lower to block indices.

Without this, there's no way to match the UBO nir_variable declarations to
the load_ubo intrinsics referencing their data.

Reviewed-by: Adam Jackson <ajax@redhat.com>
Acked-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12175>

src/compiler/nir/nir.h

@@ -567,7 +567,8 @@ typedef struct nir_variable {
 
       /**
        * The actual location of the variable in the IR. Only valid for inputs,
-       * outputs, and uniforms (including samplers and images).
+       * outputs, uniforms (including samplers and images), and for UBO and SSBO
+       * variables in GLSL.
        */
       unsigned driver_location;
 

src/compiler/nir/nir_lower_uniforms_to_ubo.c

@@ -135,6 +135,8 @@ nir_lower_uniforms_to_ubo(nir_shader *shader, bool dword_packed, bool load_vec4)
       if (!shader->info.first_ubo_is_default_ubo) {
          nir_foreach_variable_with_modes(var, shader, nir_var_mem_ubo) {
             var->data.binding++;
+            if (var->data.driver_location != -1)
+               var->data.driver_location++;
             /* only increment location for ubo arrays */
             if (glsl_without_array(var->type) == var->interface_type &&
                 glsl_type_is_array(var->type))