infer_clone/infer/src/backend/cfg.mli

(*
 * Copyright (c) 2009 - 2013 Monoidics ltd.
 * Copyright (c) 2013 - present Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *)

(**  Control Flow Graph for Interprocedural Analysis *)

open Utils

(** {2 ADT node and proc_desc} *)

type node
type cfg

(** Load a cfg from a file *)
val load_cfg_from_file: DB.filename -> cfg option

(** Save a cfg into a file, and save a copy of the source files if the boolean is true *)
val store_cfg_to_file: DB.filename -> bool -> cfg -> unit

(** proc description *)
module Procdesc : sig
  (** proc description *)
  type t

  (** Compute the distance of each node to the exit node, if not computed already *)
  val compute_distance_to_exit_node : t -> unit

  type proc_desc_builder =
    { cfg : cfg;
      name: Procname.t;
      is_defined : bool; (** is defined and not just declared *)
      proc_attributes : Sil.proc_attributes;
      ret_type : Sil.typ; (** return type *)
      formals : (string * Sil.typ) list;
      locals : (Mangled.t * Sil.typ) list;
      captured : (Mangled.t * Sil.typ) list; (** variables captured in an ObjC block *)
      loc : Sil.location;
    }

  (** Create a procdesc *)
  val create : proc_desc_builder -> t

  (** [remove cfg name remove_nodes] remove the procdesc [name] from the control flow graph [cfg]. *)
  (** It also removes all the nodes from the procedure from the cfg if remove_nodes is true *)
  val remove: cfg -> Procname.t -> bool -> unit

  (** Find the procdesc given the proc name. Return None if not found. *)
  val find_from_name : cfg -> Procname.t -> t option

  (** Get the attributes of the procedure. *)
  val get_attributes : t -> Sil.proc_attributes

  (** Get the cyclomatic complexity for the procedure *)
  val get_cyclomatic : t -> int

  val get_err_log : t -> Errlog.t

  val get_exit_node : t -> node

  (** Get flags for the proc desc *)
  val get_flags : t -> proc_flags

  (** Return name and type of formal parameters *)
  val get_formals : t -> (string * Sil.typ) list

  (** Return loc information for the procedure *)
  val get_loc : t -> Sil.location

  (** Return name and type of local variables *)
  val get_locals : t -> (Mangled.t * Sil.typ) list

  (** Return name and type of block's captured variables *)
  val get_captured : t -> (Mangled.t * Sil.typ) list

  val get_nodes : t -> node list

  (** Get the procedure's nodes up until the first branching *)
  val get_slope : t -> node list

  (** Get the sliced procedure's nodes up until the first branching *)
  val get_sliced_slope : t -> (node -> bool) -> node list

  val get_proc_name : t -> Procname.t

  (** Return the return type of the procedure and type string *)
  val get_ret_type : t -> Sil.typ

  val get_ret_var : t -> Sil.pvar

  val get_start_node : t -> node

  (** Return [true] iff the procedure is defined, and not just declared *)
  val is_defined : t -> bool

  (** iterate over all the nodes of a procedure *)
  val iter_nodes : (node -> unit) -> t -> unit

  (** iterate over the calls from the procedure: (callee,location) pairs *)
  val iter_calls : ((Procname.t * Sil.location) -> unit) -> t -> unit

  (** iterate over all nodes and their instructions *)
  val iter_instrs : (node -> Sil.instr -> unit) -> t -> unit

  (** fold over all nodes and their instructions *)
  val fold_instrs : ('a -> node -> Sil.instr -> 'a) -> 'a -> t -> 'a

  (** iterate over all nodes until we reach a branching structure *)
  val iter_slope : (node -> unit) -> t -> unit

  (** iterate over all calls until we reach a branching structure *)
  val iter_slope_calls : (Procname.t -> unit) -> t -> unit

  (** iterate between two nodes or until we reach a branching structure *)
  val iter_slope_range : (node -> unit) -> t -> node -> node -> unit

  val set_exit_node : t -> node -> unit

  (** Set a flag for the proc desc *)
  val set_flag : t -> string -> string -> unit

  val set_start_node : t -> node -> unit

  (** append a list of new local variables to the existing list of local variables *)
  val append_locals : t -> (Mangled.t * Sil.typ) list -> unit
end

(** node of the control flow graph *)
module Node : sig
  type t = node (** type of nodes *)

  (** kind of cfg node *)
  type nodekind =
    | Start_node of Procdesc.t
    | Exit_node of Procdesc.t
    | Stmt_node of string
    | Join_node
    | Prune_node of bool * Sil.if_kind * string (** (true/false branch, if_kind, comment) *)
    | Skip_node of string

  (** kind of Stmt_node for an exception handler. *)
  val exn_handler_kind : nodekind

  (** kind of Stmt_node for an exceptions sink. *)
  val exn_sink_kind : nodekind

  (** kind of Stmt_node for a throw instruction. *)
  val throw_kind : nodekind

  (** Append the instructions and temporaries to the list of instructions to execute *)
  val append_instrs_temps : t -> Sil.instr list -> Ident.t list -> unit

  (** Add the instructions and temporaries at the beginning of the list of instructions to execute *)
  val prepend_instrs_temps : t -> Sil.instr list -> Ident.t list -> unit

  (** Replace the instructions to be executed. *)
  val replace_instrs : t -> Sil.instr list -> unit

  (** Add declarations for local variables and return variable to the node *)
  val add_locals_ret_declaration : t -> (Mangled.t * Sil.typ) list -> unit

  (** restrict the cfg to the given enabled (active and not shadowed) procedures *)
  val cfg_restrict_enabled : cfg -> DB.source_file -> Procname.Set.t option -> unit

  (** Compare two nodes *)
  val compare : t -> t -> int

  (** [create cfg loc kind instrs proc_desc temps] create a new cfg node
      with the given location, kind, list of instructions,
      procdesc and list of temporary variables *)
  val create : cfg -> Sil.location -> nodekind -> Sil.instr list -> Procdesc.t -> Ident.t list -> t

  (** create a new empty cfg *)
  val create_cfg : unit -> cfg

  (** Dump extended instructions for the node *)
  val d_instrs : sub_instrs: bool -> Sil.instr option -> t -> unit

  (** Create a dummy node *)
  val dummy : unit -> t

  (** Check if two nodes are equal *)
  val equal : t -> t -> bool

  (** Get all the nodes *)
  val get_all_nodes : cfg -> t list

  (** Get the (after/before) dead program variables. After/before indicated with the true/false flag. *)
  val get_dead_pvars: t -> bool -> Sil.pvar list

  (** Get the distance to the exit node, if it has been computed *)
  val get_distance_to_exit: t -> int option

  (** Return a description of the node *)
  val get_description : Utils.printenv -> t -> string

  (** Get the exception nodes from the current node *)
  val get_exn : t -> t list

  (** Get the unique id of the node *)
  val get_id : t -> int

  (** Get the source location of the node *)
  val get_loc : t -> Sil.location

  (** Get the source location of the last instruction in the node *)
  val get_last_loc : t -> Sil.location

  (** Get the kind of the current node *)
  val get_kind : t -> nodekind

  (** Get the predecessor nodes of the current node *)
  val get_preds : t -> t list

  (** Get a list of unique nodes until the first branch starting from a node with subsequent applications of a generator function *)
  val get_generated_slope : t -> (t -> t list) -> t list

  (** Get the proc desc associated to the node *)
  val get_proc_desc : t -> Procdesc.t

  (** Get the instructions to be executed *)
  val get_instrs : t -> Sil.instr list

  (** Get the list of callee procnames from the node *)
  val get_callees : t -> Procname.t list

  (** Get the successor nodes of the current node *)
  val get_succs : t -> t list

  (** Get the successor nodes of a node where the given predicate evaluates to true *)
  val get_sliced_succs : t -> (t -> bool) -> t list

  (** Get the predecessor nodes of a node where the given predicate evaluates to true *)
  val get_sliced_preds : t -> (t -> bool) -> t list

  (** Get the temporary variables introduced for the instructions stored in the node *)
  val get_temps: t -> Ident.t list

  (** Hash function for nodes *)
  val hash : t -> int

  (** Comparison for node kind *)
  val kind_compare : nodekind -> nodekind -> int

  (** Pretty print the node *)
  val pp : Format.formatter -> t -> unit

  (** Print extended instructions for the node, highlighting the given subinstruction if present *)
  val pp_instr : printenv -> sub_instrs: bool -> Sil.instr option -> Format.formatter -> t -> unit

  (** Replace the instructions to be executed. *)
  val replace_instrs : t -> Sil.instr list -> unit

  (** Set the (after/before) dead program variables. After/before indicated with the true/false flag. *)
  val set_dead_pvars : t -> bool -> Sil.pvar list -> unit

  (** Set the node kind *)
  val set_kind : t -> nodekind -> unit

  (** Set the source location of the node *)
  val set_loc : t -> Sil.location -> unit

  (** Set the proc desc associated to the node *)
  val set_proc_desc : t -> Procdesc.t -> unit

  (** Set the successor nodes and exception nodes, and build predecessor links *)
  val set_succs_exn : t -> t list -> t list -> unit

  (** Set the temporary variables *)
  val set_temps : t -> Ident.t list -> unit
end

(** Hash table with nodes as keys. *)
module NodeHash : Hashtbl.S with type key = Node.t

(** Set of nodes. *)
module NodeSet : Set.S with type elt = Node.t

val pp_node_list : Format.formatter -> Node.t list -> unit

(** {2 Functions for manipulating an interprocedural CFG} *)

(** Iterate over all the procdesc's *)
val iter_proc_desc : cfg -> (Procname.t -> Procdesc.t -> unit) -> unit

(** Iterate over all the types (and subtypes) in the CFG *)
val iter_types : cfg -> (Sil.typ -> unit) -> unit

(** Get all the procedures (defined and declared) *)
val get_all_procs : cfg -> Procdesc.t list

(** Get the procedures whose body is defined in this cfg *)
val get_defined_procs : cfg -> Procdesc.t list

(** Get the objc procedures whose body is generated *)
val get_objc_generated_procs : cfg -> Procdesc.t list

(** get the function names which should be analyzed before the other ones *)
val get_priority_procnames : cfg -> Procname.Set.t

(** set the function names whose address has been taken in this file *)
val set_procname_priority : cfg -> Procname.t -> unit

(** add instructions to remove temporaries *)
val add_removetemps_instructions : cfg -> unit

(** add instructions to perform abstraction *)
val add_abstraction_instructions : cfg -> unit

(** remove the return variable from the prop *)
val remove_ret : Procdesc.t -> Prop.normal Prop.t -> Prop.normal Prop.t

(** remove locals and return variable from the prop *)
val remove_locals_ret : Procdesc.t -> Prop.normal Prop.t -> Prop.normal Prop.t

(** Deallocate the stack variables in [pvars], and replace them by normal variables.
    Return the list of stack variables whose address was still present after deallocation. *)
val remove_locals_formals : Procdesc.t -> Prop.normal Prop.t -> Sil.pvar list * Prop.normal Prop.t

(** remove seed vars from a prop *)
val remove_seed_vars : 'a Prop.t -> Prop.normal Prop.t

(** checks whether a cfg is connected or not *)
val check_cfg_connectedness : cfg -> unit

(** Given a mangled name of a block return its procdesc if exists*)
val get_block_pdesc : cfg -> Mangled.t -> Procdesc.t option

(** return true if the pdesc associated with [pname] changed since the last analysis run or did
    not exist in the last analysis run *)
val pdesc_is_changed : cfg -> Procname.t -> bool

(** Removes seeds variables from a prop corresponding to captured variables in an objc block *)
val remove_seed_captured_vars_block : Mangled.t list -> Prop.normal Prop.t -> Prop.normal Prop.t