nir: add some nir_parameter fields

These will be used in future to do more validation on functions as
the glsl nir linker is expanded. The first use is in the following
patch.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27841>

src/compiler/glsl/glsl_to_nir.cpp

@@ -660,12 +660,17 @@ nir_visitor::create_function(ir_function_signature *ir)
       /* The return value is a variable deref (basically an out parameter) */
       func->params[np].num_components = 1;
       func->params[np].bit_size = 32;
+      func->params[np].type = ir->return_type;
+      func->params[np].is_return = true;
       np++;
    }
 
    foreach_in_list(ir_variable, param, &ir->parameters) {
       func->params[np].num_components = 1;
       func->params[np].bit_size = 32;
+
+      func->params[np].type = param->type;
+      func->params[np].is_return = false;
       np++;
    }
    assert(np == func->num_params);

src/compiler/nir/nir.h

@@ -3468,6 +3468,12 @@ nir_cf_list_is_empty_block(struct exec_list *cf_list)
 typedef struct {
    uint8_t num_components;
    uint8_t bit_size;
+
+   /* True if this paramater is actually the function return variable */
+   bool is_return;
+
+   /* The type of the function param */
+   const struct glsl_type *type;
 } nir_parameter;
 
 typedef struct nir_function {