Start working on name generation for the synthesis

5 files changed, 317 insertions, 1 deletions

diff --git a/TODO.md b/TODO.md
index d92e9640..ff7ba7ab 100644
--- a/TODO.md
+++ b/TODO.md
@@ -2,6 +2,8 @@
 
 0. update the end borrows internal to abstractions to not introduce a Bottom
 
+1. reorder the branches of matches
+
 1. stateful maps/sets modules (hashtbl?)
 
 1. Check the occurrence of visitors like visit_AEndedMutLoan: the parameters are
diff --git a/src/Collections.ml b/src/Collections.ml
index 54d0acac..ee998546 100644
--- a/src/Collections.ml
+++ b/src/Collections.ml
@@ -47,6 +47,17 @@ module type OrderedType = sig
   val show_t : t -> string
 end
 
+(** Ordered string *)
+module OrderedString : OrderedType with type t = string = struct
+  include String
+
+  let to_string s = s
+
+  let pp_t fmt s = Format.pp_print_string fmt s
+
+  let show_t s = s
+end
+
 module type Map = sig
   include Map.S
 
@@ -155,3 +166,199 @@ module MakeSet (Ord : OrderedType) : Set with type elt = Ord.t = struct
 
   let show s = to_string None s
 end
+
+(** A map where the bindings are injective (i.e., if two keys are distinct,
+    their bindings are distinct).
+    
+    This is useful for instance when generating mappings from our internal
+    identifiers to names (i.e., strings) when generating code, in order to
+    make sure that we don't have potentially dangerous collisions.
+ *)
+module type MapInj = sig
+  type key
+
+  type elem
+
+  type t
+
+  val empty : t
+
+  val is_empty : t -> bool
+
+  val mem : key -> t -> bool
+
+  val add : key -> elem -> t -> t
+
+  val singleton : key -> elem -> t
+
+  val remove : key -> t -> t
+
+  val compare : (elem -> elem -> int) -> t -> t -> int
+
+  val equal : (elem -> elem -> bool) -> t -> t -> bool
+
+  val iter : (key -> elem -> unit) -> t -> unit
+
+  val fold : (key -> elem -> 'b -> 'b) -> t -> 'b -> 'b
+
+  val for_all : (key -> elem -> bool) -> t -> bool
+
+  val exists : (key -> elem -> bool) -> t -> bool
+
+  val filter : (key -> elem -> bool) -> t -> t
+
+  val partition : (key -> elem -> bool) -> t -> t * t
+
+  val cardinal : t -> int
+
+  val bindings : t -> (key * elem) list
+
+  val min_binding : t -> key * elem
+
+  val min_binding_opt : t -> (key * elem) option
+
+  val max_binding : t -> key * elem
+
+  val max_binding_opt : t -> (key * elem) option
+
+  val choose : t -> key * elem
+
+  val choose_opt : t -> (key * elem) option
+
+  val split : key -> t -> t * elem option * t
+
+  val find : key -> t -> elem
+
+  val find_opt : key -> t -> elem option
+
+  val find_first : (key -> bool) -> t -> key * elem
+
+  val find_first_opt : (key -> bool) -> t -> (key * elem) option
+
+  val find_last : (key -> bool) -> t -> key * elem
+
+  val find_last_opt : (key -> bool) -> t -> (key * elem) option
+
+  val to_seq : t -> (key * elem) Seq.t
+
+  val to_seq_from : key -> t -> (key * elem) Seq.t
+
+  val add_seq : (key * elem) Seq.t -> t -> t
+
+  val of_seq : (key * elem) Seq.t -> t
+end
+
+(** See [MapInj] *)
+module MakeMapInj (Key : OrderedType) (Elem : OrderedType) :
+  MapInj with type key = Key.t with type elem = Elem.t = struct
+  module Map = MakeMap (Key)
+  module Set = MakeSet (Elem)
+
+  type key = Key.t
+
+  type elem = Elem.t
+
+  type t = { map : elem Map.t; elems : Set.t }
+
+  let empty = { map = Map.empty; elems = Set.empty }
+
+  let is_empty m = Map.is_empty m.map
+
+  let mem k m = Map.mem k m.map
+
+  let add k e m =
+    assert (not (Set.mem e m.elems));
+    { map = Map.add k e m.map; elems = Set.add e m.elems }
+
+  let singleton k e = { map = Map.singleton k e; elems = Set.singleton e }
+
+  let remove k m =
+    match Map.find_opt k m.map with
+    | None -> m
+    | Some x -> { map = Map.remove k m.map; elems = Set.remove x m.elems }
+
+  let compare f m1 m2 = Map.compare f m1.map m2.map
+
+  let equal f m1 m2 = Map.equal f m1.map m2.map
+
+  let iter f m = Map.iter f m.map
+
+  let fold f m x = Map.fold f m.map x
+
+  let for_all f m = Map.for_all f m.map
+
+  let exists f m = Map.exists f m.map
+
+  (** Small helper *)
+  let bindings_to_elems_set (bls : (key * elem) list) : Set.t =
+    let elems = List.map snd bls in
+    let elems = List.fold_left (fun s e -> Set.add e s) Set.empty elems in
+    elems
+
+  (** Small helper *)
+  let map_to_elems_set (map : elem Map.t) : Set.t =
+    bindings_to_elems_set (Map.bindings map)
+
+  (** Small helper *)
+  let map_to_t (map : elem Map.t) : t =
+    let elems = map_to_elems_set map in
+    { map; elems }
+
+  let filter f m =
+    let map = Map.filter f m.map in
+    let elems = map_to_elems_set map in
+    { map; elems }
+
+  let partition f m =
+    let map1, map2 = Map.partition f m.map in
+    (map_to_t map1, map_to_t map2)
+
+  let cardinal m = Map.cardinal m.map
+
+  let bindings m = Map.bindings m.map
+
+  let min_binding m = Map.min_binding m.map
+
+  let min_binding_opt m = Map.min_binding_opt m.map
+
+  let max_binding m = Map.max_binding m.map
+
+  let max_binding_opt m = Map.max_binding_opt m.map
+
+  let choose m = Map.choose m.map
+
+  let choose_opt m = Map.choose_opt m.map
+
+  let split k m =
+    let l, data, r = Map.split k m.map in
+    let l = map_to_t l in
+    let r = map_to_t r in
+    (l, data, r)
+
+  let find k m = Map.find k m.map
+
+  let find_opt k m = Map.find_opt k m.map
+
+  let find_first k m = Map.find_first k m.map
+
+  let find_first_opt k m = Map.find_first_opt k m.map
+
+  let find_last k m = Map.find_last k m.map
+
+  let find_last_opt k m = Map.find_last_opt k m.map
+
+  let to_seq m = Map.to_seq m.map
+
+  let to_seq_from k m = Map.to_seq_from k m.map
+
+  let rec add_seq s m =
+    (* Note that it is important to check that we don't add bindings mapping
+     * to the same element *)
+    match s () with
+    | Seq.Nil -> m
+    | Seq.Cons ((k, e), s) ->
+        let m = add k e m in
+        add_seq s m
+
+  let of_seq s = add_seq s empty
+end
diff --git a/src/Identifiers.ml b/src/Identifiers.ml
index f2b88fd4..4880a19a 100644
--- a/src/Identifiers.ml
+++ b/src/Identifiers.ml
@@ -147,6 +147,21 @@ module IdGen () : Id = struct
   module Map = C.MakeMap (Ord)
 end
 
-type name = string list [@@deriving show]
+type name = string list [@@deriving show, ord]
 (** A name such as: `std::collections::vector` (which would be represented as
     [["std"; "collections"; "vector"]]) *)
+
+module NameOrderedType : C.OrderedType = struct
+  type t = name
+
+  let compare = compare_name
+
+  let to_string = String.concat "::"
+
+  let pp_t = pp_name
+
+  let show_t = show_name
+end
+
+module NameMap = C.MakeMap (NameOrderedType)
+module NameSet = C.MakeSet (NameOrderedType)
diff --git a/src/SymbolicToPure.ml b/src/SymbolicToPure.ml
new file mode 100644
index 00000000..7792db4b
--- /dev/null
+++ b/src/SymbolicToPure.ml
@@ -0,0 +1,91 @@
+open Errors
+module Id = Identifiers
+module T = Types
+module V = Values
+module E = Expressions
+module A = CfimAst
+module S = SymbolicAst
+
+type name =
+  | FunName of A.FunDefId.id * V.BackwardFunctionId.id option
+  | TypeName of T.TypeDefId.id
+[@@deriving show, ord]
+
+let name_to_string (n : name) : string = show_name n
+
+module NameOrderedType = struct
+  type t = name
+
+  let compare = compare_name
+
+  let to_string = name_to_string
+
+  let pp_t = pp_name
+
+  let show_t = show_name
+end
+
+module NameMap = Collections.MakeMapInj (NameOrderedType) (Id.NameOrderedType)
+(** Notice that we use the *injective* map to map identifiers to names.
+
+    Of course, even if those names (which are string lists) don't collide,
+    when converting them to strings we can still introduce collisions: we
+    check that later.
+    
+    Note that we use injective maps for sanity: though we write the name
+    generation with collision in mind, it is always good to have such checks.
+ *)
+
+let fun_to_name (fdef : A.fun_def) (bid : V.BackwardFunctionId.id option) :
+    Id.name =
+  let sg = fdef.signature in
+  (* General function to generate a suffix for a region group
+   * (i.e., an abstraction)*)
+  let rg_to_string (rg : T.region_var_group) : string =
+    (* We are just a little bit smart:
+       - if there is exactly one region id in the region group and this region
+         has a name, we use this name
+       - otherwise, we use the region number (note that region names shouldn't
+         start with numbers)
+    *)
+    match rg.T.regions with
+    | [ rid ] -> (
+        let rvar = T.RegionVarId.nth sg.region_params rid in
+        match rvar.name with
+        | None -> T.RegionGroupId.to_string rg.T.id
+        | Some name -> name)
+    | _ -> T.RegionGroupId.to_string rg.T.id
+  in
+  (* There are several cases:
+     - this is a forward function: we add "_fwd"
+     - this is a backward function:
+       - this function has one backward function: we add "_back"
+       - this function has several backward function: we add "_back" and an
+         additional suffix to identify the precise backward function
+  *)
+  let suffix =
+    match bid with
+    | None -> "_fwd"
+    | Some bid -> (
+        match sg.regions_hierarchy with
+        | [] ->
+            failwith "Unreachable"
+            (* we can't get there if we ask for a back function *)
+        | [ _ ] ->
+            (* Exactly one backward function *)
+            "_back"
+        | _ ->
+            (* Several backward functions - note that **we use the backward function id
+             * as if it were a region group id** (there is a direct mapping between the
+             * two - TODO: merge them) *)
+            let rg = V.BackwardFunctionId.nth sg.regions_hierarchy bid in
+            "_back" ^ rg_to_string rg)
+  in
+  (* Final name *)
+  let rec add_to_last (n : Id.name) : Id.name =
+    match n with
+    | [] -> failwith "Unreachable"
+    | [ x ] -> [ x ^ suffix ]
+    | x :: n -> x :: add_to_last n
+  in
+  add_to_last fdef.name
diff --git a/src/main.ml b/src/main.ml
index 3772e7ac..67db362e 100644
--- a/src/main.ml
+++ b/src/main.ml
@@ -9,6 +9,7 @@ module TA = TypesAnalysis
 module P = Pure
 open SymbolicAstUtils
 open PrintSymbolicAst
+open SymbolicToPure
 
 (* This is necessary to have a backtrace when raising exceptions - for some
  * reason, the -g option doesn't work.