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(*
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* Copyright (c) 2016 - present Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*)
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(** Module for naming heap locations via the path used to access them (e.g., x.f.g, y[a].b) *)
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type base = Var.t * Typ.t
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type access =
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| FieldAccess of Ident.fieldname * Typ.t (* field name * field type *)
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| ArrayAccess of Typ.t (* array element type. index is unknown *)
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(** root var, and a list of accesses. closest to the root var is first that is, x.f.g is represented
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as (x, [f; g]) *)
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type raw = base * access list
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type t =
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| Exact of raw (** precise representation of an access path, e.g. x.f.g *)
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| Abstracted of raw (** abstraction of heap reachable from an access path, e.g. x.f* *)
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val base_compare : base -> base -> int
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val base_equal : base -> base -> bool
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val raw_compare : raw -> raw -> int
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val raw_equal : raw -> raw -> bool
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val access_compare : access -> access -> int
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val access_equal : access -> access -> bool
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(** create a base from a pvar *)
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val base_of_pvar : Pvar.t -> Typ.t -> base
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(** create a base from an ident *)
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val base_of_id : Ident.t -> Typ.t -> base
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(** create an access path from a pvar *)
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val of_pvar : Pvar.t -> Typ.t -> raw
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(** create an access path from an ident *)
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val of_id : Ident.t -> Typ.t -> raw
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(** convert [exp] to a raw access path, resolving identifiers using [f_resolve_id] *)
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val of_exp : Exp.t -> Typ.t -> f_resolve_id:(Var.t -> raw option) -> raw option
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(** append new accesses to an existing access path; e.g., `append_access x.f [g, h]` produces
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`x.f.g.h` *)
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val append : raw -> access list -> raw
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(** swap base of existing access path for [base_var] (e.g., `with_base_bvar x y.f.g` produces
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`x.f.g` *)
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val with_base_var : Var.t -> t -> t
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(** return true if [ap1] is a prefix of [ap2]. returns true for equal access paths *)
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val is_prefix : raw -> raw -> bool
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val pp_access : Format.formatter -> access -> unit
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val pp_raw : Format.formatter -> raw -> unit
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val compare : t -> t -> int
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val equal : t -> t -> bool
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(** extract a raw access path from its wrapper *)
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val extract : t -> raw
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(** return true if [t] is an exact representation of an access path, false if it's an abstraction *)
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val is_exact : t -> bool
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(** return true if \gamma(lhs) \subseteq \gamma(rhs) *)
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val (<=) : lhs:t -> rhs:t -> bool
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val pp_base : Format.formatter -> base -> unit
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val pp : Format.formatter -> t -> unit
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