nir: Add compute shader shared variable storage class

Previously we were receiving shared variable accesses via a lowered
intrinsic function from glsl. This change allows us to send in
variables instead. For example, when converting from SPIR-V.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/compiler/nir/nir.c

@@ -39,6 +39,7 @@ nir_shader_create(void *mem_ctx,
    exec_list_make_empty(&shader->uniforms);
    exec_list_make_empty(&shader->inputs);
    exec_list_make_empty(&shader->outputs);
+   exec_list_make_empty(&shader->shared);
 
    shader->options = options;
    memset(&shader->info, 0, sizeof(shader->info));
@@ -136,6 +137,11 @@ nir_shader_add_variable(nir_shader *shader, nir_variable *var)
       exec_list_push_tail(&shader->uniforms, &var->node);
       break;
 
+   case nir_var_shared:
+      assert(shader->stage == MESA_SHADER_COMPUTE);
+      exec_list_push_tail(&shader->shared, &var->node);
+      break;
+
    case nir_var_system_value:
       exec_list_push_tail(&shader->system_values, &var->node);
       break;