infer_clone/infer/src/backend/utils.ml

(*
 * 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.
 *)

(** General utility functions and definition with global scope *)

module F = Format

(** List police: don't use the list module to avoid non-tail recursive
    functions and builtin equality. Use IList instead. *)
module List = struct end

(** initial time of the analysis, i.e. when this module is loaded, gotten from Unix.time *)
let initial_analysis_time = Unix.time ()

(** precise time of day at the start of the analysis *)
let initial_timeofday = Unix.gettimeofday ()

(** {2 Generic Utility Functions} *)

(** Compare police: generic compare disabled. *)
let compare = ()

let string_equal (s1: string) (s2: string) = s1 = s2

let string_compare (s1: string) (s2: string) = Pervasives.compare s1 s2

let float_compare (f1: float) (f2: float) = Pervasives.compare f1 f2

let bool_compare (b1: bool) (b2: bool) = Pervasives.compare b1 b2

let bool_equal (b1: bool) (b2: bool) = b1 = b2

(** Extend and equality function to an option type. *)
let opt_equal cmp x1 x2 = match x1, x2 with
  | None, None -> true
  | Some _, None -> false
  | None, Some _ -> false
  | Some y1, Some y2 -> cmp y1 y2

(** Efficient comparison for integers *)
let int_compare (i: int) (j: int) = i - j

let int_equal (i: int) (j: int) = i = j

(** Generic comparison of pairs given a compare function for each element of the pair. *)
let pair_compare compare compare' (x1, y1) (x2, y2) =
  let n = compare x1 x2 in
  if n <> 0 then n else compare' y1 y2

(** Generic comparison of pairs given a compare function for each element of the triple *)
let triple_compare compare compare' compare'' (x1, y1, z1) (x2, y2, z2) =
  let n = compare x1 x2 in
  if n <> 0 then n else let n = compare' y1 y2 in
    if n <> 0 then n else compare'' z1 z2

(** {2 Useful Modules} *)

(** Set of integers *)
module IntSet =
  Set.Make(struct
    type t = int
    let compare = int_compare
  end)

(** Set of strings *)
module StringSet = Set.Make(String)

(** Pretty print a set of strings *)
let pp_stringset fmt ss =
  StringSet.iter (fun s -> F.fprintf fmt "%s " s) ss

(** Maps from integers *)
module IntMap = Map.Make (struct
    type t = int
    let compare = int_compare
  end)

(** Maps from strings *)
module StringMap = Map.Make (struct
    type t = string
    let compare (s1: string) (s2: string) = Pervasives.compare s1 s2 end)

(** {2 Printing} *)

(** Kind of simple printing: default or with full types *)
type pp_simple_kind = PP_SIM_DEFAULT | PP_SIM_WITH_TYP

(** Kind of printing *)
type printkind = PP_TEXT | PP_LATEX | PP_HTML

(** Colors supported in printing *)
type color = Black | Blue | Green | Orange | Red

(** map subexpressions (as Obj.t element compared by physical equality) to colors *)
type colormap = Obj.t -> color

(** Print environment threaded through all the printing functions *)
type printenv = {
  pe_opt : pp_simple_kind; (** Current option for simple printing *)
  pe_kind : printkind; (** Current kind of printing *)
  pe_cmap_norm : colormap; (** Current colormap for the normal part *)
  pe_cmap_foot : colormap; (** Current colormap for the footprint part *)
  pe_color : color; (** Current color *)
  pe_obj_sub : (Obj.t -> Obj.t) option (** generic object substitution *)
}

(** Create a colormap of a given color *)
let colormap_from_color color (o: Obj.t) = color

(** standard colormap: black *)
let colormap_black (o: Obj.t) = Black

(** red colormap *)
let colormap_red (o: Obj.t) = Red

(** Default text print environment *)
let pe_text =
  { pe_opt = PP_SIM_DEFAULT;
    pe_kind = PP_TEXT;
    pe_cmap_norm = colormap_black;
    pe_cmap_foot = colormap_black;
    pe_color = Black;
    pe_obj_sub = None }

(** Default html print environment *)
let pe_html color =
  { pe_text with
    pe_kind = PP_HTML;
    pe_cmap_norm = colormap_from_color color;
    pe_cmap_foot = colormap_from_color color;
    pe_color = color }

(** Default latex print environment *)
let pe_latex color =
  { pe_opt = PP_SIM_DEFAULT;
    pe_kind = PP_LATEX;
    pe_cmap_norm = colormap_from_color color;
    pe_cmap_foot = colormap_from_color color;
    pe_color = color;
    pe_obj_sub = None }

(** Extend the normal colormap for the given object with the given color *)
let pe_extend_colormap pe (x: Obj.t) (c: color) =
  let colormap (y: Obj.t) =
    if x == y then c
    else pe.pe_cmap_norm y in
  { pe with pe_cmap_norm = colormap }

(** Set the object substitution, which is supposed to preserve the type.
    Currently only used for a map from (identifier) expressions to the program var containing them *)
let pe_set_obj_sub pe (sub: 'a -> 'a) =
  let new_obj_sub x =
    let x' = Obj.repr (sub (Obj.obj x)) in
    match pe.pe_obj_sub with
    | None -> x'
    | Some sub' -> sub' x' in
  { pe with pe_obj_sub = Some (new_obj_sub) }

(** Reset the object substitution, so that no substitution takes place *)
let pe_reset_obj_sub pe =
  { pe with pe_obj_sub = None }

(** string representation of colors *)
let color_string = function
  | Black -> "color_black"
  | Blue -> "color_blue"
  | Green -> "color_green"
  | Orange -> "color_orange"
  | Red -> "color_red"

(** Pretty print a space-separated sequence *)
let rec pp_seq pp f = function
  | [] -> ()
  | [x] -> F.fprintf f "%a" pp x
  | x:: l -> F.fprintf f "%a %a" pp x (pp_seq pp) l

(** Print a comma-separated sequence *)
let rec pp_comma_seq pp f = function
  | [] -> ()
  | [x] -> F.fprintf f "%a" pp x
  | x:: l -> F.fprintf f "%a,%a" pp x (pp_comma_seq pp) l

(** Print a ;-separated sequence. *)
let rec _pp_semicolon_seq oneline pe pp f =
  let pp_sep fmt () =
    if oneline then F.fprintf fmt " " else F.fprintf fmt "@\n" in
  function
  | [] -> ()
  | [x] -> F.fprintf f "%a" pp x
  | x:: l ->
      (match pe.pe_kind with
       | PP_TEXT | PP_HTML ->
           F.fprintf f "%a ; %a%a" pp x pp_sep () (_pp_semicolon_seq oneline pe pp) l
       | PP_LATEX ->
           F.fprintf f "%a ;\\\\%a %a" pp x pp_sep () (_pp_semicolon_seq oneline pe pp) l)

(** Print a ;-separated sequence with newlines. *)
let pp_semicolon_seq pe = _pp_semicolon_seq false pe

(** Print a ;-separated sequence on one line. *)
let pp_semicolon_seq_oneline pe = _pp_semicolon_seq true pe

(** Print an or-separated sequence. *)
let pp_or_seq pe pp f = function
  | [] -> ()
  | [x] -> F.fprintf f "%a" pp x
  | x:: l ->
      (match pe.pe_kind with
       | PP_TEXT ->
           F.fprintf f "%a || %a" pp x (pp_semicolon_seq pe pp) l
       | PP_HTML ->
           F.fprintf f "%a &or; %a" pp x (pp_semicolon_seq pe pp) l
       | PP_LATEX ->
           F.fprintf f "%a \\vee %a" pp x (pp_semicolon_seq pe pp) l)

(** Produce a string from a 1-argument pretty printer function *)
let pp_to_string pp x =
  let buf = Buffer.create 1 in
  let fmt = Format.formatter_of_buffer buf in
  Format.fprintf fmt "%a@?" pp x;
  Buffer.contents buf

(** Print the current time and date in a format similar to the "date" command *)
let pp_current_time f () =
  let tm = Unix.localtime (Unix.time ()) in
  F.fprintf f "%02d/%02d/%4d %02d:%02d" tm.Unix.tm_mday tm.Unix.tm_mon (tm.Unix.tm_year + 1900) tm.Unix.tm_hour tm.Unix.tm_min

(** Print the time in seconds elapsed since the beginning of the execution of the current command. *)
let pp_elapsed_time fmt () =
  let elapsed = Unix.gettimeofday () -. initial_timeofday in
  Format.fprintf fmt "%f" elapsed

(** Type of location in ml source: file,line,column *)
type ml_location = string * int * int

(** Turn an ml location into a string *)
let ml_location_string ((file: string), (line: int), (column: int)) =
  "File " ^ file ^ " Line " ^ string_of_int line ^ " Column " ^ string_of_int column

(** Pretty print a location of ml source *)
let pp_ml_location fmt mloc =
  F.fprintf fmt "%s" (ml_location_string mloc)

let pp_ml_location_opt fmt mloco =
  if !Config.developer_mode then match mloco with
    | None -> ()
    | Some mloc -> F.fprintf fmt "(%a)" pp_ml_location mloc

(** {2 SymOp and Timeouts: units of symbolic execution} *)

type timeout_kind =
  | TOtime (* max time exceeded *)
  | TOsymops of int (* max symop's exceeded *)
  | TOrecursion of int (* max recursion level exceeded *)

(** Timeout exception *)
exception Timeout_exe of timeout_kind

let exn_not_timeout = function
  | Timeout_exe _ -> false
  | _ -> true

let symops_timeout, seconds_timeout =
  (* default timeout and long timeout are the same for now, but this will change shortly *)
  let default_symops_timeout = 333 in
  let default_seconds_timeout = 10 in
  let long_symops_timeout = 1000 in
  let long_seconds_timeout = 30 in
  if Config.analyze_models then
    (* use longer timeouts when analyzing models *)
    long_symops_timeout, long_seconds_timeout
  else
    default_symops_timeout, default_seconds_timeout

(** number of symops to multiply by the number of iterations, after which there is a timeout *)
let symops_per_iteration = ref symops_timeout

(** number of seconds to multiply by the number of iterations, after which there is a timeout *)
let seconds_per_iteration = ref seconds_timeout

(** timeout value from the -iterations command line option *)
let iterations_cmdline = ref 1

(** Timeout in seconds for each function *)
let timeout_seconds = ref !seconds_per_iteration

(** Timeout in SymOps *)
let timeout_symops = ref !symops_per_iteration

(** Set the timeout values in seconds and symops, computed as a multiple of the integer parameter *)
let set_iterations n =
  timeout_symops := !symops_per_iteration * n;
  timeout_seconds := !seconds_per_iteration * n

let get_timeout_seconds () = !timeout_seconds

(** Count the number of symbolic operations *)
module SymOp = struct
  (** Number of symop's *)
  let symop_count = ref 0

  (** Total number of symop's since the beginning *)
  let symop_total = ref 0

  (** Only throw timeout exception when alarm is active *)
  let alarm_active = ref false

  (** last wallclock set by an alarm, if any *)
  let last_wallclock = ref None

  (** handler for the wallclock timeout *)
  let wallclock_timeout_handler = ref None

  (** set the handler for the wallclock timeout *)
  let set_wallclock_timeout_handler handler =
    wallclock_timeout_handler := Some handler

  (** Set the wallclock alarm checked at every pay() *)
  let set_wallclock_alarm nsecs =
    last_wallclock := Some (Unix.gettimeofday () +. float_of_int nsecs)

  (** Unset the wallclock alarm checked at every pay() *)
  let unset_wallclock_alarm () =
    last_wallclock := None

  (** if the wallclock alarm has expired, raise a timeout exception *)
  let check_wallclock_alarm () =
    match !last_wallclock, !wallclock_timeout_handler with
    | Some alarm_time, Some handler when Unix.gettimeofday () >= alarm_time ->
        unset_wallclock_alarm ();
        handler ()
    | _ -> ()

  (** Return the total number of symop's since the beginning *)
  let get_total () = !symop_total

  (** Reset the total number of symop's *)
  let reset_total () = symop_total := 0

  (** timer at load time *)
  let initial_time = Unix.gettimeofday ()

  (** Time in the beginning *)
  let timer = ref initial_time

  (** Count one symop *)
  let pay () =
    incr symop_count; incr symop_total;
    if !symop_count > !timeout_symops && !alarm_active
    then raise (Timeout_exe (TOsymops !symop_count));
    check_wallclock_alarm ()

  (** Reset the counters *)
  let reset () =
    symop_count := 0;
    timer := Unix.gettimeofday ()

  (** Reset the counter and activate the alarm *)
  let set_alarm () =
    reset ();
    alarm_active := true

  (** De-activate the alarm *)
  let unset_alarm () =
    alarm_active := false

  let report_stats f symops elapsed =
    F.fprintf f "SymOp stats -- symops:%d time:%f symops/sec:%f" symops elapsed ((float_of_int symops) /. elapsed)

  (** Report the stats since the last reset *)
  let report f () =
    let elapsed = Unix.gettimeofday () -. !timer in
    report_stats f !symop_count elapsed

  (** Report the stats since the loading of this module *)
  let report_total f () =
    let elapsed = Unix.gettimeofday () -. initial_time in
    report_stats f !symop_total elapsed
end

(** Check if the lhs is a substring of the rhs. *)
let string_is_prefix s1 s2 =
  String.length s1 <= String.length s2 &&
  String.sub s2 0 (String.length s1) = s1

(** Check if the lhs is a postfix of the rhs. *)
let string_is_suffix s1 s2 =
  let l1 = String.length s1 in
  let l2 = String.length s2 in
  l1 <= l2 &&
  String.sub s2 (l2 - l1) l1 = s1

(** Check if the lhs is contained in the rhs. *)
let string_contains s1 s2 =
  let rexp = Str.regexp_string s1 in
  try
    ignore (Str.search_forward rexp s2 0);
    true
  with Not_found -> false

(** Split a string across the given character, if given. (e.g. split first.second with '.').*)
let string_split_character s c =
  try
    let index = String.rindex s c in
    let lhs = String.sub s 0 index in
    let rhs = String.sub s (index + 1) ((String.length s) - (1 + index)) in
    (Some lhs, rhs)
  with Not_found -> (None, s)

let string_value_or_empty_string
    (string_option: string option): string =
  match string_option with
  | Some s -> s
  | None -> ""

(** read a source file and return a list of lines, or None in case of error *)
let read_file fname =
  let res = ref [] in
  let cin_ref = ref None in
  let cleanup () =
    match !cin_ref with
    | None -> ()
    | Some cin -> close_in cin in
  try
    let cin = open_in fname in
    cin_ref := Some cin;
    while true do
      let line = input_line cin in
      res := line :: !res
    done;
    assert false
  with
  | End_of_file ->
      cleanup ();
      Some (IList.rev !res)
  | Sys_error _ ->
      cleanup ();
      None

(** copy a source file, return the number of lines, or None in case of error *)
let copy_file fname_from fname_to =
  let res = ref 0 in
  let cin_ref = ref None in
  let cout_ref = ref None in
  let cleanup () =
    begin match !cin_ref with
      | None -> ()
      | Some cin -> close_in cin
    end;
    begin match !cout_ref with
      | None -> ()
      | Some cout -> close_out cout
    end in
  try
    let cin = open_in fname_from in
    cin_ref := Some cin;
    let cout = open_out fname_to in
    cout_ref := Some cout;
    while true do
      let line = input_line cin in
      output_string cout line;
      output_char cout '\n';
      incr res
    done;
    assert false
  with
  | End_of_file ->
      cleanup ();
      Some !res
  | Sys_error _ ->
      cleanup();
      None

module FileLOC = (** count lines of code of files and keep processed results in a cache *)
struct
  let include_loc_hash = Hashtbl.create 1

  let reset () = Hashtbl.clear include_loc_hash

  let file_get_loc fname =
    try Hashtbl.find include_loc_hash fname with Not_found ->
      let loc = match read_file fname with
        | None -> 0
        | Some l -> IList.length l in
      Hashtbl.add include_loc_hash fname loc;
      loc
end

(** type for files used for printing *)
type outfile =
  { fname : string; (** name of the file *)
    out_c : out_channel; (** output channel *)
    fmt : F.formatter (** formatter for printing *) }

(** create an outfile for the command line *)
let create_outfile fname =
  try
    let out_c = open_out fname in
    let fmt = F.formatter_of_out_channel out_c in
    Some { fname = fname; out_c = out_c; fmt = fmt }
  with Sys_error _ ->
    F.fprintf F.err_formatter "error: cannot create file %s@." fname;
    None

(** operate on an outfile reference if it is not None *)
let do_outf outf_ref f =
  match !outf_ref with
  | None -> ()
  | Some outf ->
      f outf

(** close an outfile *)
let close_outf outf =
  close_out outf.out_c

(** convert a filename to absolute path and normalize by removing occurrences of "." and ".." *)
module FileNormalize = struct
  let rec fname_to_list_rev fname =
    if fname = "" then [] else
      let base = Filename.basename fname in
      let dir = Filename.dirname fname in
      let does_not_split = (* make sure it terminates whatever the implementation of Filename *)
        fname = base || String.length dir >= String.length fname in
      if does_not_split then [fname]
      else base :: fname_to_list_rev dir

  (* split a file name into a list of strings representing it as a path *)
  let fname_to_list fname =
    IList.rev (fname_to_list_rev fname)

  (* concatenate a list of strings representing a path into a filename *)
  let rec list_to_fname base path = match path with
    | [] -> base
    | x :: path' -> list_to_fname (Filename.concat base x) path'

  (* normalize a path where done_l is a reversed path from the root already normalized *)
  (* and todo_l is the path still to normalize *)
  let rec normalize done_l todo_l = match done_l, todo_l with
    | _, y :: tl when y = Filename.current_dir_name -> (* path/. --> path *)
        normalize done_l tl
    | [root], y :: tl when y = Filename.parent_dir_name -> (* /.. --> / *)
        normalize done_l tl
    | x :: dl, y :: tl when y = Filename.parent_dir_name -> (* path/x/.. --> path *)
        normalize dl tl
    | _, y :: tl -> normalize (y :: done_l) tl
    | _, [] -> IList.rev done_l

  (* check if the filename contains "." or ".." *)
  let fname_contains_current_parent fname =
    let l = fname_to_list fname in
    IList.exists (fun x -> x = Filename.current_dir_name || x = Filename.parent_dir_name) l

  (* convert a filename to absolute path, if necessary, and normalize "." and ".." *)
  let fname_to_absolute_normalize fname =
    let is_relative = Filename.is_relative fname in
    let must_normalize = fname_contains_current_parent fname in
    let simple_case () =
      if is_relative then Filename.concat (Unix.getcwd ()) fname
      else fname in
    if must_normalize then begin
      let done_l, todo_l =
        if is_relative then
          fname_to_list_rev (Unix.getcwd ()), fname_to_list fname
        else match fname_to_list fname with
          | [] -> [fname], [] (* should not happen *)
          | root :: l -> [root], l in
      let normal_l = normalize done_l todo_l in
      match normal_l with
      | base :: l -> list_to_fname base l
      | [] -> (* should not happen *) simple_case ()
    end
    else simple_case ()

  (*
  let test () =
  let test_fname fname =
  let fname' = fname_to_absolute_normalize fname in
  Format.fprintf Format.std_formatter "fname %s --> %s@." fname fname' in
  let tests = [".";
  "..";
  "aaa.c";
  "/";
  "/..";
  "../test.c";
  "src/../././test.c"] in
  List.map test_fname tests
  *)
end

(** Convert a filename to an absolute one if it is relative, and normalize "." and ".." *)
let filename_to_absolute fname =
  FileNormalize.fname_to_absolute_normalize fname

(** Convert an absolute filename to one relative to the current directory. *)
let filename_to_relative root fname =
  let string_strict_subtract s1 s2 =
    let n1, n2 = String.length s1, String.length s2 in
    if n1 < n2 && String.sub s2 0 n1 = s1 then
      String.sub s2 (n1 + 1) (n2 - (n1 + 1))
    else s2 in
  let norm_root = (* norm_root is root without any trailing / *)
    Filename.concat (Filename.dirname root) (Filename.basename root) in
  let remainder = (* remove the path prefix to root including trailing / *)
    string_strict_subtract norm_root fname in
  remainder


(* Type of command-line arguments before processing *)
type arg_list = (string * Arg.spec * string option * string) list

let arg_desc_filter options_to_keep =
  IList.filter (function (option_name, _, _, _) -> IList.mem string_equal option_name options_to_keep)

let base_arg_desc =
  [
    "-results_dir",
    Arg.String (fun s -> Config.results_dir := s),
    Some "dir",
    "set the project results directory (default dir=" ^ Config.default_results_dir ^ ")";
    "-coverage",
    Arg.Unit (fun () -> Config.worklist_mode:= 2),
    None,
    "analysis mode to maximize coverage (can take longer)";
    "-lib",
    Arg.String (fun s -> Config.specs_library := filename_to_absolute s :: !Config.specs_library),
    Some "dir",
    "add dir to the list of directories to be searched for spec files";
    "-models",
    Arg.String (fun s -> Config.add_models (filename_to_absolute s)),
    Some "zip file",
    "add a zip file containing the models";
    "-ziplib",
    Arg.String (fun s -> Config.add_zip_library (filename_to_absolute s)),
    Some "zip file",
    "add a zip file containing library spec files";
    "-project_root",
    Arg.String (fun s -> Config.project_root := Some (filename_to_absolute s)),
    Some "dir",
    "root directory of the project";
    "-infer_cache",
    Arg.String (fun s -> Config.JarCache.infer_cache := Some (filename_to_absolute s)),
    Some "dir",
    "Select a directory to contain the infer cache";
  ]

let reserved_arg_desc =
  [
    "-absstruct", Arg.Set_int Config.abs_struct, Some "n", "abstraction level for fields of structs (default n = 1)";
    "-absval", Arg.Set_int Config.abs_val, Some "n", "abstraction level for expressions (default n = 2)";
    "-arraylevel", Arg.Set_int Config.array_level, Some "n", "the level of treating the array indexing and pointer arithmetic (default n = 0)";
    "-developer_mode", Arg.Set Config.developer_mode, None, "reserved";
    "-dotty", Arg.Set Config.write_dotty, None, "produce dotty files in the results directory";
    "-exit_node_bias", Arg.Unit (fun () -> Config.worklist_mode:= 1), None, "nodes nearest the exit node are analyzed first";
    "-html", Arg.Set Config.write_html, None, "produce hmtl output in the results directory";
    "-join_cond", Arg.Set_int Config.join_cond, Some "n", "set the strength of the final information-loss check used by the join (default n=1)";
    "-leak", Arg.Set Config.allowleak, None, "forget leaks during abstraction";
    "-monitor_prop_size", Arg.Set Config.monitor_prop_size, None, "monitor size of props";
    "-nelseg", Arg.Set Config.nelseg, None, "use only nonempty lsegs";
    "-noliveness", Arg.Clear Config.liveness, None, "turn the dead program variable elimination off";
    "-noprintdiff", Arg.Clear Config.print_using_diff, None, "turn off highlighting diff w.r.t. previous prop in printing";
    "-notest", Arg.Clear Config.test, None, "turn test mode off";
    "-only_footprint", Arg.Set Config.only_footprint, None, "skip the re-execution phase";
    "-print_types", Arg.Set Config.print_types, None, "print types in symbolic heaps";
    "-set_pp_margin", Arg.Int (fun i -> F.set_margin i), Some "n", "set right margin for the pretty printing functions";
    "-slice_fun", Arg.Set_string Config.slice_fun, None, "analyze only functions recursively called by function given as argument";
    "-spec_abs_level", Arg.Set_int Config.spec_abs_level, Some "n", "set the level of abstracting the postconditions of discovered specs (default n=1)";
    "-trace_error", Arg.Set Config.trace_error, None, "turn on tracing of error explanation";
    "-trace_join", Arg.Set Config.trace_join, None, "turn on tracing of join";
    "-trace_rearrange", Arg.Set Config.trace_rearrange, None, "turn on tracing of rearrangement";
    "-visits_bias", Arg.Unit (fun () -> Config.worklist_mode:= 2), None, "nodes visited fewer times are analyzed first";
  ]

(**************** START MODULE Arg2 -- modified from Arg in the ocaml distribution ***************)
module Arg2 = struct
  type key = string
  type doc = string
  type usage_msg = string
  type anon_fun = (string -> unit)

  type spec = Arg.spec

  exception Bad of string
  exception Help of string

  type error =
    | Unknown of string
    | Wrong of string * string * string  (* option, actual, expected *)
    | Missing of string
    | Message of string

  exception Stop of error (* used internally *)

  open Printf

  let rec assoc3 x l =
    match l with
    | [] -> raise Not_found
    | (y1, y2, y3) :: t when y1 = x -> y2
    | _ :: t -> assoc3 x t

  let make_symlist prefix sep suffix l =
    match l with
    | [] -> "<none>"
    | h:: t -> (IList.fold_left (fun x y -> x ^ sep ^ y) (prefix ^ h) t) ^ suffix

  let print_spec buf (key, spec, doc) =
    match spec with
    | Arg.Symbol (l, _) -> bprintf buf "  %s %s%s\n" key (make_symlist "{" "|" "}" l)
                             doc
    | _ ->
        let sep = if String.length doc != 0 && String.get doc 0 = '=' then "" else " " in
        bprintf buf "  %s%s%s\n" key sep doc

  let help_action () = raise (Stop (Unknown "-help"))

  let add_help speclist =
    let add1 =
      try ignore (assoc3 "-help" speclist); []
      with Not_found ->
        ["-help", Arg.Unit help_action, " Display this list of options"]
    and add2 =
      try ignore (assoc3 "--help" speclist); []
      with Not_found ->
        ["--help", Arg.Unit help_action, " Display this list of options"]
    in
    speclist @ (add1 @ add2)

  let usage_b buf speclist errmsg =
    bprintf buf "%s\n" errmsg;
    IList.iter (print_spec buf) (add_help speclist)

  let usage speclist errmsg =
    let b = Buffer.create 200 in
    usage_b b speclist errmsg;
    eprintf "%s" (Buffer.contents b)
  let current = ref 0;;

  let parse_argv ?(current = current) argv speclist anonfun errmsg =
    let l = Array.length argv in
    let b = Buffer.create 200 in
    let initpos = !current in
    let stop error =
      let progname = if initpos < l then argv.(initpos) else "(?)" in
      begin match error with
        | Unknown "-help" -> ()
        | Unknown "--help" -> ()
        | Unknown s ->
            bprintf b "%s: unknown option `%s'.\n" progname s
        | Missing s ->
            bprintf b "%s: option `%s' needs an argument.\n" progname s
        | Wrong (opt, arg, expected) ->
            bprintf b "%s: wrong argument `%s'; option `%s' expects %s.\n"
              progname arg opt expected
        | Message s ->
            bprintf b "%s: %s.\n" progname s
      end;
      usage_b b speclist errmsg;
      if error = Unknown "-help" || error = Unknown "--help"
      then raise (Help (Buffer.contents b))
      else raise (Bad (Buffer.contents b))
    in
    incr current;
    while !current < l do
      let s = argv.(!current) in
      if String.length s >= 1 && String.get s 0 = '-' then begin
        let action =
          try assoc3 s speclist
          with Not_found -> stop (Unknown s)
        in
        begin try
            let rec treat_action = function
              | Arg.Unit f -> f ();
              | Arg.Bool f when !current + 1 < l ->
                  let arg = argv.(!current + 1) in
                  begin try f (bool_of_string arg)
                    with Invalid_argument "bool_of_string" ->
                      raise (Stop (Wrong (s, arg, "a boolean")))
                  end;
                  incr current;
              | Arg.Set r -> r := true;
              | Arg.Clear r -> r := false;
              | Arg.String f when !current + 1 < l ->
                  f argv.(!current + 1);
                  incr current;
              | Arg.Symbol (symb, f) when !current + 1 < l ->
                  let arg = argv.(!current + 1) in
                  if IList.mem string_equal arg symb then begin
                    f argv.(!current + 1);
                    incr current;
                  end else begin
                    raise (Stop (Wrong (s, arg, "one of: "
                                                ^ (make_symlist "" " " "" symb))))
                  end
              | Arg.Set_string r when !current + 1 < l ->
                  r := argv.(!current + 1);
                  incr current;
              | Arg.Int f when !current + 1 < l ->
                  let arg = argv.(!current + 1) in
                  begin try f (int_of_string arg)
                    with Failure "int_of_string" ->
                      raise (Stop (Wrong (s, arg, "an integer")))
                  end;
                  incr current;
              | Arg.Set_int r when !current + 1 < l ->
                  let arg = argv.(!current + 1) in
                  begin try r := (int_of_string arg)
                    with Failure "int_of_string" ->
                      raise (Stop (Wrong (s, arg, "an integer")))
                  end;
                  incr current;
              | Arg.Float f when !current + 1 < l ->
                  let arg = argv.(!current + 1) in
                  begin try f (float_of_string arg);
                    with Failure "float_of_string" ->
                      raise (Stop (Wrong (s, arg, "a float")))
                  end;
                  incr current;
              | Arg.Set_float r when !current + 1 < l ->
                  let arg = argv.(!current + 1) in
                  begin try r := (float_of_string arg);
                    with Failure "float_of_string" ->
                      raise (Stop (Wrong (s, arg, "a float")))
                  end;
                  incr current;
              | Arg.Tuple specs ->
                  IList.iter treat_action specs;
              | Arg.Rest f ->
                  while !current < l - 1 do
                    f argv.(!current + 1);
                    incr current;
                  done;
              | _ -> raise (Stop (Missing s))
            in
            treat_action action
          with Bad m -> stop (Message m);
             | Stop e -> stop e;
        end;
        incr current;
      end else begin
        (try anonfun s with Bad m -> stop (Message m));
        incr current;
      end;
    done

  let parse l f msg =
    try
      parse_argv Sys.argv l f msg;
    with
    | Bad msg -> eprintf "%s" msg; exit 2;
    | Help msg -> printf "%s" msg; exit 0

  (** Custom version of Arg.aling so that keywords are on one line and documentation is on the next *)
  let align arg_desc =
    let do_arg (key, spec, doc) =
      let first_space =
        try
          let index = String.index doc ' ' in
          if String.get doc index = '=' then 0 else index
        with Not_found -> 0 in
      let len = String.length doc in
      let doc1 = String.sub doc 0 first_space in
      let doc2 = String.sub doc first_space (len - first_space) in
      if len = 0 then (key, spec, doc)
      else (key, spec, doc1 ^ "\n     " ^ doc2) in
    IList.map do_arg arg_desc

  type aligned = (key * spec * doc)

  let to_arg_desc x = x
  let from_arg_desc x = x

  (** Create a group of sorted command-line arguments *)
  let create_options_desc double_minus title unsorted_desc =
    let handle_double_minus (opname, spec, param_opt, text) = match param_opt with
      | None ->
          if double_minus then ("-"^opname, spec, " " ^ text)
          else (opname, spec, " " ^ text)
      | Some param ->
          if double_minus then ("-"^opname, spec, "=" ^ param ^ " " ^ text)
          else (opname, spec, param ^ " " ^ text) in
    let unsorted_desc' = IList.map handle_double_minus unsorted_desc in
    let dlist =
      ("", Arg.Unit (fun () -> ()), " \n  " ^ title ^ "\n") ::
      IList.sort (fun (x, _, _) (y, _, _) -> Pervasives.compare x y) unsorted_desc' in
    align dlist
end
(********** END OF MODULE Arg2 **********)

(** Escape a string for use in a CSV or XML file: replace reserved characters with escape sequences *)
module Escape = struct
  (** apply a map function for escape sequences *)
  let escape_map map_fun s =
    let len = String.length s in
    let buf = Buffer.create len in
    for i = 0 to len - 1 do
      let c = String.unsafe_get s i in
      match map_fun c with
      | None -> Buffer.add_char buf c
      | Some s' -> Buffer.add_string buf s'
    done;
    Buffer.contents buf

  let escape_csv s =
    let map = function
      | '"' -> Some "\"\""
      | c when Char.code c > 127 -> Some "?" (* non-ascii character: escape *)
      | _ -> None in
    escape_map map s

  let escape_xml s =
    let map = function
      | '"' -> (* on next line to avoid bad indentation *)
          Some "&quot;"
      | '>' -> Some "&gt;"
      | '<' -> Some "&lt;"
      | '&' -> Some "&amp;"
      | '%' -> Some "&#37;"
      | c when Char.code c > 127 -> (* non-ascii character: escape *)
          Some ("&#" ^ string_of_int (Char.code c) ^ ";")
      | _ -> None in
    escape_map map s

  let escape_dotty s =
    let map = function
      | '"' -> Some "\\\""
      | '\\' -> Some "\\\\"
      | _ -> None in
    escape_map map s

  let escape_path s =
    let map_csv = function
      | c ->
          if (Char.escaped c) = Filename.dir_sep
          then Some "_"
          else None in
    escape_map map_csv s
end


(** flags for a procedure *)
type proc_flags = (string, string) Hashtbl.t

let proc_flags_empty () : proc_flags = Hashtbl.create 1

let proc_flag_iterations = "iterations"
let proc_flag_skip = "skip"
let proc_flag_ignore_return = "ignore_return"

let proc_flags_add proc_flags key value =
  Hashtbl.replace proc_flags key value

let proc_flags_find proc_flags key =
  Hashtbl.find proc_flags key

let join_strings sep = function
  | [] -> ""
  | hd:: tl ->
      IList.fold_left (fun str p -> str ^ sep ^ p) hd tl

let next compare =
  fun x y n ->
    if n <> 0 then n
    else compare x y


let directory_fold f init path =
  let collect current_dir (accu, dirs) path =
    let full_path = (Filename.concat current_dir path) in
    try
      if Sys.is_directory full_path then
        (accu, full_path:: dirs)
      else
        (f accu full_path, dirs)
    with Sys_error _ ->
      (accu, dirs) in
  let rec loop accu dirs =
    match dirs with
    | [] -> accu
    | d:: tl ->
        let (new_accu, new_dirs) = Array.fold_left (collect d) (accu, tl) (Sys.readdir d) in
        loop new_accu new_dirs in
  if Sys.is_directory path then
    loop init [path]
  else
    f init path


let directory_iter f path =
  let apply current_dir dirs path =
    let full_path = (Filename.concat current_dir path) in
    try
      if Sys.is_directory full_path then
        full_path:: dirs
      else
        let () = f full_path in
        dirs
    with Sys_error _ ->
      dirs in
  let rec loop dirs =
    match dirs with
    | [] -> ()
    | d:: tl ->
        let new_dirs = Array.fold_left (apply d) tl (Sys.readdir d) in
        loop new_dirs in
  if Sys.is_directory path then
    loop [path]
  else
    f path

type analyzer = Infer | Eradicate | Checkers | Tracing

let analyzers = [Infer; Eradicate; Checkers; Tracing]

let string_of_analyzer = function
  | Infer -> "infer"
  | Eradicate -> "eradicate"
  | Checkers -> "checkers"
  | Tracing -> "tracing"

exception Unknown_analyzer

let analyzer_of_string = function
  | "infer" -> Infer
  | "eradicate" -> Eradicate
  | "checkers" -> Checkers
  | "tracing" -> Tracing
  | _ -> raise Unknown_analyzer