nir: add max_ifc_array_access field to vars

This will be used in following patches by the nir based glsl
linker code.

Acked-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31137>

src/compiler/glsl/glsl_to_nir.cpp

@@ -597,6 +597,16 @@ nir_visitor::visit(ir_variable *ir)
    var->data.explicit_xfb_buffer = ir->data.explicit_xfb_buffer;
    var->data.explicit_xfb_stride = ir->data.explicit_xfb_stride;
 
+   if (ir->is_interface_instance()) {
+      int *max_ifc_array_access = ir->get_max_ifc_array_access();
+      if (max_ifc_array_access) {
+         var->max_ifc_array_access =
+            rzalloc_array(var, int, ir->get_interface_type()->length);
+         memcpy(var->max_ifc_array_access, max_ifc_array_access,
+                ir->get_interface_type()->length * sizeof(unsigned));
+      }
+   }
+
    var->num_state_slots = ir->get_num_state_slots();
    if (var->num_state_slots > 0) {
       var->state_slots = rzalloc_array(var, nir_state_slot,

src/compiler/nir/nir.h

@@ -837,6 +837,18 @@ typedef struct nir_variable {
    /* Number of nir_variable_data members */
    uint16_t num_members;
 
+   /**
+    * For variables with non NULL interface_type, this points to an array of
+    * integers such that if the ith member of the interface block is an array,
+    * max_ifc_array_access[i] is the maximum array element of that member that
+    * has been accessed.  If the ith member of the interface block is not an
+    * array, max_ifc_array_access[i] is unused.
+    *
+    * For variables whose type is not an interface block, this pointer is
+    * NULL.
+    */
+   int *max_ifc_array_access;
+
    /**
     * Built-in state that backs this uniform
     *

src/compiler/nir/nir_clone.c

@@ -163,6 +163,13 @@ nir_variable_clone(const nir_variable *var, nir_shader *shader)
    }
    nvar->interface_type = var->interface_type;
 
+   if (var->max_ifc_array_access) {
+      nvar->max_ifc_array_access =
+         rzalloc_array(nvar, int, var->interface_type->length);
+      memcpy(nvar->max_ifc_array_access, var->max_ifc_array_access,
+             var->interface_type->length * sizeof(unsigned));
+   }
+
    nvar->num_members = var->num_members;
    if (var->num_members) {
       nvar->members = ralloc_array(nvar, struct nir_variable_data,