(** Tag variable declarations with stack frame indices. *)

(** The assembly phase needs to know indices of variables in the current stack
    frame to be pass to [load|store] instructions. This phase traverses the AST
    and adds [Index] annotations based on a counter that is increased when
    declaration is encountered.

    A problem, however, is that uses of these declarations do not inherit these
    annotations, since the declaration annotations are not references.
    Therefore, this phase first strips all context analysis by replacing
    variable/function uses with the original [Var|Assign|FunCall] nodes. Then,
    index analysis is performed on declarations. Finally, the
    {!Context.analyse} traversal is re-run to carry the [Index] annotations to
    the variable/function uses. Note that we can safely assume that no errors
    will occur during this context analysis, since incorrect uses would have
    been identified by the earlier context analysis already.
    *)

(** Main phase function, called by {!Main}. *)
val phase : Main.phase_func