flambda-backend: Speedups in Asmlink (#8)

Author: mshinwell

utils/consistbl.ml

@@ -60,25 +60,18 @@ end) = struct
 
   let source tbl name = snd (Module_name.Tbl.find tbl name)
 
+  let find t name =
+    match Module_name.Tbl.find t name with
+    | exception Not_found -> None
+    | (crc, _) -> Some crc
+
   let extract l tbl =
     let l = List.sort_uniq Module_name.compare l in
-    List.fold_left
-      (fun assc name ->
-         try
-           let (crc, _) = Module_name.Tbl.find tbl name in
-             (name, Some crc) :: assc
-         with Not_found ->
-           (name, None) :: assc)
-      [] l
+    List.fold_left (fun assc name -> (name, find tbl name) :: assc) [] l
 
   let extract_map mod_names tbl =
     Module_name.Set.fold
-      (fun name result ->
-         try
-           let (crc, _) = Module_name.Tbl.find tbl name in
-           Module_name.Map.add name (Some crc) result
-         with Not_found ->
-           Module_name.Map.add name None result)
+      (fun name result -> Module_name.Map.add name (find tbl name) result)
       mod_names
       Module_name.Map.empty
 

utils/consistbl.mli

@@ -57,6 +57,8 @@ end) : sig
            if the latter has an associated CRC in [tbl].
            Raise [Not_found] otherwise. *)
 
+  val find: t -> Module_name.t -> Digest.t option
+
   val extract: Module_name.t list -> t -> (Module_name.t * Digest.t option) list
         (* [extract tbl names] returns an associative list mapping each string
            in [names] to the CRC associated with it in [tbl]. If no CRC is