specialize String.make

Author: bobzhang

jscomp/core/lam_analysis.ml

@@ -56,6 +56,7 @@ let rec no_side_effects (lam : Lam.t) : bool =
             (* non-observable side effect *)    
             | "caml_sys_get_config"
             | "caml_sys_get_argv" (* should be fine *)
+            | "caml_string_repeat"
             | "caml_make_vect"
             | "caml_create_bytes"
             | "caml_obj_dup"

jscomp/core/lam_dispatch_primitive.ml

@@ -380,6 +380,20 @@ let translate loc (prim_name : string)
           E.string_comp Ge  e0 e1
         | _ -> assert false 
       end
+    | "caml_string_repeat"
+      ->   
+      begin match args with 
+        | [ n ; {expression_desc = Number (Int {i})} ] ->   
+          let str = (String.make 1 (Char.chr (Int32.to_int i))) in
+          begin match n.expression_desc with 
+            | Number (Int {i = 1l}) -> E.str str 
+            | _ -> 
+              E.call (E.dot (E.str str) "repeat") [n]
+                ~info:Js_call_info.builtin_runtime_call
+          end
+        | _ ->     
+          E.runtime_call Js_runtime_modules.string "make" args
+      end
     | "caml_string_greaterthan"
       -> 
       begin match args with 
@@ -475,7 +489,7 @@ let translate loc (prim_name : string)
       | _ -> assert false 
       end 
     | "caml_create_bytes"  
-    | "caml_create_string" -> 
+       -> 
       (* Bytes.create *)
       (* Note that for invalid range, JS raise an Exception RangeError, 
          here in OCaml it's [Invalid_argument], we have to preserve this semantics.

jscomp/runtime/caml_string.ml

@@ -36,18 +36,8 @@ let get s i=
     raise (Invalid_argument "index out of bounds") 
   else Caml_string_extern.unsafe_get s i
 
-(* let caml_string_get16 s i = 
-  Caml_char.code (Caml_string_extern.unsafe_get s i) + Caml_char.code (Caml_string_extern.unsafe_get s (i+1)) lsl 8  
-
-let caml_string_get32 s i = 
-  Caml_char.code (Caml_string_extern.unsafe_get s i) + 
-  Caml_char.code (Caml_string_extern.unsafe_get s (i+1)) lsl 8  + 
-  Caml_char.code (Caml_string_extern.unsafe_get s (i+2)) lsl 16 + 
-  Caml_char.code (Caml_string_extern.unsafe_get s (i+3)) lsl 24 *)
-
-
-(* let get s i =
-  if i < 0 || i >= Caml_string_extern.length s then
-    raise (Invalid_argument "index out of bounds")
-  else Caml_string_extern.unsafe_get s i      
- *)
+let make n (ch : char) : string = 
+  (Caml_string_extern.of_char ch)   
+   |. Caml_string_extern.repeat   n
+   
+  

jscomp/runtime/caml_string.mli

@@ -24,3 +24,5 @@
 
 
 val get : string -> int -> char 
+
+val make : int -> char -> string

jscomp/stdlib-406/string.ml

@@ -36,9 +36,9 @@ module B = Bytes
 
 let bts = B.unsafe_to_string
 let bos = B.unsafe_of_string
-(*-FIXME: replaced by Belt.String.repeat *)
-let make n c =
-  B.make n c |> bts
+
+external make : int -> char -> string = "caml_string_repeat"  
+
 let init n f =
   B.init n f |> bts
 let copy s =