refine let_kind in js ir, simplify [string_of_int] and other micro-optimizations

jscomp/j.ml

@@ -100,7 +100,7 @@ and expression_desc =
        since GC does not rely on it
      *)
   | Array_copy of expression (* shallow copy, like [x.slice] *)
-  | Array_append of expression * expression list (* For [caml_array_append]*)
+  | Array_append of expression * expression (* For [caml_array_append]*)
   | Tag_ml_obj of expression
   | String_append of expression * expression 
   | Int_of_boolean of expression 

jscomp/js_dump.ml

@@ -432,7 +432,7 @@ and
     P.group f 1 (fun _ -> 
         let cxt = expression 15 cxt f e in
         P.string f ".concat";
-        P.paren_group f 1 (fun _ -> arguments cxt f el))
+        P.paren_group f 1 (fun _ -> arguments cxt f [el]))
 
   | Array_copy e -> 
     P.group f 1 (fun _ -> 

jscomp/js_fold.ml

@@ -339,8 +339,7 @@ class virtual fold =
       | Array_of_size _x -> let o = o#expression _x in o
       | Array_copy _x -> let o = o#expression _x in o
       | Array_append (_x, _x_i1) ->
-          let o = o#expression _x in
-          let o = o#list (fun o -> o#expression) _x_i1 in o
+          let o = o#expression _x in let o = o#expression _x_i1 in o
       | Tag_ml_obj _x -> let o = o#expression _x in o
       | String_append (_x, _x_i1) ->
           let o = o#expression _x in let o = o#expression _x_i1 in o

jscomp/js_helper.ml

@@ -142,15 +142,26 @@ module Exp = struct
 
   let str ?(pure=true) ?comment s : t =  {expression_desc = Str (pure,s); comment}
 
-  let any_to_string ?comment (e : t) : t =  
+  let anything_to_string ?comment (e : t) : t =  
     match e.expression_desc with 
     | Str _ -> e 
     | _ -> {expression_desc = Anything_to_string e ; comment}
-
+
+  (* we can do constant folding here, but need to make sure the result is consistent
+     {[
+       let f x = string_of_int x        
+       ;; f 3            
+     ]}     
+     {[
+       string_of_int 3
+     ]}
+  *)
+  let int_to_string ?comment (e : t) : t = 
+    anything_to_string ?comment e 
   (* Shared mutable state is evil 
       [Js_fun_env.empty] is a mutable state ..
    *)    
-  let efun ?comment  ?immutable_mask
+  let fun_ ?comment  ?immutable_mask
       params block  : t = 
     let len = List.length params in
     {
@@ -308,6 +319,8 @@ module Exp = struct
         String_append ({expression_desc = Str(_,c)} ,d) ->
         string_append ?comment (string_append a (str (b ^ c))) d 
     | Str (_,a), Str (_,b) -> str ?comment (a ^ b)
+    | _, Anything_to_string b -> string_append ?comment e b 
+    | Anything_to_string b, _ -> string_append ?comment b el
     | _, _ -> {comment ; expression_desc = String_append(e,el)}
 
 
@@ -911,12 +924,7 @@ module Stmt = struct
         { statement_desc = Exp e; comment}
 
   let declare_variable ?comment  ?ident_info  ~kind (v:Ident.t)  : t=
-    let property : J.property = 
-      match (kind : Lambda.let_kind ) with 
-      | (Alias | Strict | StrictOpt )
-        -> Immutable 
-      | Variable -> Mutable 
-    in
+    let property : J.property =  kind in
     let ident_info  : J.ident_info  = 
       match ident_info with
       | None ->  {used_stats = NA}
@@ -927,12 +935,7 @@ module Stmt = struct
      comment}
 
   let define ?comment  ?ident_info ~kind (v:Ident.t) exp    : t=
-    let property : J.property = 
-      match (kind : Lambda.let_kind ) with 
-      | (Alias | Strict | StrictOpt )
-        -> Immutable 
-      | Variable -> Mutable 
-    in
+    let property : J.property =  kind in
     let ident_info  : J.ident_info  = 
       match ident_info with
       | None ->  {used_stats = NA}
@@ -1130,10 +1133,10 @@ module Stmt = struct
 
 
 
-  let const_variable ?comment  ?exp (v:Ident.t)  : t=
+  let alias_variable ?comment  ?exp (v:Ident.t)  : t=
     {statement_desc = 
      Variable {
-     ident = v; value = exp; property = Immutable;
+     ident = v; value = exp; property = Alias;
      ident_info = {used_stats = NA }   };
      comment}
 
@@ -1152,7 +1155,7 @@ module Stmt = struct
       statement_desc = 
       J.Variable { ident =  id; 
                    value = Some (Exp.unit ()) ;
-                   property = Mutable;
+                   property = Variable;
                    ident_info = {used_stats = NA}
                  };
       comment

jscomp/js_helper.mli

@@ -96,7 +96,7 @@ module Exp : sig
 
   val str : ?pure:bool -> ?comment:string -> string -> t 
 
-  val efun : ?comment:string ->
+  val fun_ : ?comment:string ->
     ?immutable_mask:bool array -> J.ident list -> J.block -> t
 
   val econd : ?comment:string -> t -> t -> t -> t
@@ -126,7 +126,7 @@ module Exp : sig
 
   val char_to_int : unary_op
 
-  val array_append : ?comment:string -> t -> t list -> t
+  val array_append : binary_op
 
   val array_copy : unary_op
   val string_append : binary_op
@@ -189,7 +189,8 @@ module Exp : sig
 
   val dump : ?comment:string -> Js_op.level -> t list -> t
 
-  val any_to_string : unary_op
+  val anything_to_string : unary_op
+  val int_to_string : unary_op
   val to_json_string : unary_op
 
   val new_ : ?comment:string -> J.expression -> J.expression list -> t
@@ -285,7 +286,7 @@ module Stmt : sig
     ?ident_info:J.ident_info ->
     kind:Lambda.let_kind -> Ident.t -> J.expression  -> t
 
-  val const_variable :
+  val alias_variable :
       ?comment:string -> ?exp:J.expression -> Ident.t -> t
   val assign : ?comment:string  -> J.ident -> J.expression -> t
 

jscomp/js_inline_and_eliminate.ml

@@ -166,7 +166,7 @@ let subst name export_set stats  =
             ->  self#statement st :: self#block rest 
 
           | { value = Some {expression_desc = Fun (params, block, _env) ; comment = _}; 
-              property = Immutable;
+              property = (Alias | StrictOpt | Strict);
               ident_info = {used_stats = Once_pure };
               ident = _
             } as v

jscomp/js_map.ml

@@ -371,8 +371,7 @@ class virtual map =
       | Array_copy _x -> let _x = o#expression _x in Array_copy _x
       | Array_append (_x, _x_i1) ->
           let _x = o#expression _x in
-          let _x_i1 = o#list (fun o -> o#expression) _x_i1
-          in Array_append (_x, _x_i1)
+          let _x_i1 = o#expression _x_i1 in Array_append (_x, _x_i1)
       | Tag_ml_obj _x -> let _x = o#expression _x in Tag_ml_obj _x
       | String_append (_x, _x_i1) ->
           let _x = o#expression _x in

jscomp/js_op.ml

@@ -127,9 +127,11 @@ type kind =
   | Runtime 
   | External of string
 
-type property = 
-  | Mutable
-  | Immutable
+type property = Lambda.let_kind = 
+  | Strict
+  | Alias
+  | StrictOpt 
+  | Variable
 
 type int_or_char = 
     { i :  int;

jscomp/js_pass_flatten_and_mark_dead.ml

@@ -172,7 +172,7 @@ let subst_map name = object (self)
       {v with statement_desc =  (Exp x)}
 
     | Variable ({ ident ; 
-                  property = Immutable;
+                  property = (Strict | StrictOpt | Alias);
                   value = Some ({expression_desc = (Array ( _:: _ :: _ as ls, Immutable))} as array)
                 } as variable) -> 
       (** If we do this, we should prevent incorrect inlning to inline it into an array :) 

jscomp/js_pass_scope.ml

@@ -196,10 +196,10 @@ let scope_pass  =
       | { ident ; value; property  }  -> 
         let obj = 
           (match self#get_in_loop, property with 
-           | true, Mutable 
+           | true, Variable 
              -> 
              self#add_loop_mutable_variable ident 
-           | true, Immutable
+           | true, (Strict | StrictOpt | Alias)
            (* Not real true immutable in javascript 
                since it's in the loop 
 
@@ -235,10 +235,10 @@ let scope_pass  =
                    (* else  *)
                    self#add_loop_mutable_variable ident
              end
-           | false, Mutable
+           | false, Variable
              -> 
              self#add_mutable_variable ident      
-           | false, Immutable
+           | false, (Strict | StrictOpt | Alias)
              -> self
           )#add_defined_ident ident
         in

jscomp/lam_compile.ml

@@ -90,7 +90,7 @@ and compile_recursive_let (cxt : Lam_compile_defs.cxt) (id : Ident.t) (arg : Lam
               jmp_table = Lam_compile_defs.empty_handler_map}  body in
         if ret.triggered then 
           let body_block = Js_output.to_block output in
-          E.efun (* TODO:  save computation of length several times *)
+          E.fun_ (* TODO:  save computation of length several times *)
             ~immutable_mask:ret.immutable_mask
             (List.map (fun x -> 
                  try Ident_map.find x ret.new_params with  Not_found -> x)
@@ -107,7 +107,7 @@ and compile_recursive_let (cxt : Lam_compile_defs.cxt) (id : Ident.t) (arg : Lam
             ]
 
         else            (* TODO:  save computation of length several times *)
-          E.efun params (Js_output.to_block output )
+          E.fun_ params (Js_output.to_block output )
       ), [] 
   | (Lprim(Pmakeblock _ , _) )  -> 
     (* Lconst should not appear here if we do [scc]
@@ -261,7 +261,7 @@ and
     match lam with 
     | Lfunction(kind, params, body) ->
       Js_output.handle_name_tail st should_return lam 
-        (E.efun
+        (E.fun_
            params
            (* Invariant:  jmp_table can not across function boundary,
               here we share env
@@ -918,11 +918,11 @@ and
                 (*   | String_length e  *)
                 (*     ->  *)
                 (*       let len = Ext_ident.create "_length" in *)
-                (*       b2 @ [ S.const_variable len ~exp:e2 ],  J.Finish (Id len ) *)
+                (*       b2 @ [ S.alias_variable len ~exp:e2 ],  J.Finish (Id len ) *)
                 (*   | _ ->  *)
                 (*       (\* TODO: guess a better name when possible*\) *)
                 (*       let len = Ext_ident.create "_finish" in *)
-                (*       b2 @ [S.const_variable len ~exp:e2],  J.Finish (Id len) *)
+                (*       b2 @ [S.alias_variable len ~exp:e2],  J.Finish (Id len) *)
                 (* in  *)
 
                 b1 @ (S.define ~kind:Variable id e1 :: b2 ) @ ([

jscomp/lam_compile_global.ml

@@ -115,10 +115,13 @@ let get_exp_with_args (id : Ident.t) (pos : int) env (args : J.expression list)
                             id.flags
                             pos
                          ))
+
     ~found:(fun {id; name;arity; _} -> 
         match id, name,  args with 
         | {name = "Pervasives"; _}, "^", [ e0 ; e1] ->  
           E.string_append e0 e1 
+        | {name = "Pervasives"; _}, "string_of_int", [e] 
+          -> E.int_to_string e 
         | {name = "Pervasives"; _}, "print_endline", ([ _ ] as args) ->  
           E.seq (E.dump Log args) (E.unit ())
         | {name = "Pervasives"; _}, "prerr_endline", ([ _ ] as args) ->  

jscomp/lam_compile_group.ml

@@ -36,10 +36,11 @@ let compile_group ({filename = file_name; env;} as meta : Lam_stats.meta)
         2. [E.builtin_dot] for javascript builtin
         3. [E.mldot]
      *)
+  (* ATTENTION: check {!Lam_compile_global} for consistency  *)      
   (** Special handling for values in [Pervasives] *)
   | Single(_, ({name="stdout"|"stderr"|"stdin";_} as id),_ ),
     "pervasives.ml" -> 
-    Js_output.of_stmt @@ S.const_variable id
+    Js_output.of_stmt @@ S.alias_variable id
       ~exp:(E.runtime_ref  Js_helper.io id.name)
   (* 
          we delegate [stdout, stderr, and stdin] into [caml_io] module, 
@@ -49,11 +50,11 @@ let compile_group ({filename = file_name; env;} as meta : Lam_stats.meta)
       *)                     
   | Single(_, ({name="infinity";_} as id),_ ),  "pervasives.ml" 
     -> (* TODO: check relative path to compiler*)
-    Js_output.of_stmt @@ S.const_variable id ~exp:(E.js_global "Infinity")
+    Js_output.of_stmt @@ S.alias_variable id ~exp:(E.js_global "Infinity")
   | Single(_, ({name="neg_infinity";_} as id),_ ), "pervasives.ml" ->
-    Js_output.of_stmt @@ S.const_variable id ~exp:(E.js_global "-Infinity")
+    Js_output.of_stmt @@ S.alias_variable id ~exp:(E.js_global "-Infinity")
   | Single(_, ({name="nan";_} as id),_ ),  "pervasives.ml" ->
-    Js_output.of_stmt @@ S.const_variable id ~exp:(E.js_global "NaN")
+    Js_output.of_stmt @@ S.alias_variable id ~exp:(E.js_global "NaN")
 
   (* TODO: 
       Make it more safe, we should rewrite the last one...
@@ -62,55 +63,63 @@ let compile_group ({filename = file_name; env;} as meta : Lam_stats.meta)
         [Lam_dispatch_primitive], here it makes an exception since this function is not a primitive
   *) 
   | Single(_, ({name="^";_} as id),_ ),  "pervasives.ml" ->
-    Js_output.of_stmt @@ S.const_variable id 
-      ~exp:(E.runtime_ref Js_helper.string "add")
+    Js_output.of_stmt @@ S.alias_variable id 
+      ~exp:(let a = Ext_ident.create "a" in 
+            let b = Ext_ident.create "b" in
+            E.fun_ [a;b] [S.return (E.string_append (E.var a) (E.var b))]
+            )
 
   (* QUICK hack to make hello world example nicer,
      Note the arity of [print_endline] is already analyzed before, 
      so it should be safe
   *)
   | Single(_, ({name="print_endline";_} as id),_ ),  "pervasives.ml" ->
-    Js_output.of_stmt @@ S.const_variable id 
+    Js_output.of_stmt @@ S.alias_variable id 
       ~exp:(E.js_global "console.log")
   | Single(_, ({name="prerr_endline";_} as id),_ ),  "pervasives.ml" ->
-    Js_output.of_stmt @@ S.const_variable id 
+    Js_output.of_stmt @@ S.alias_variable id 
       ~exp:(E.js_global "console.error")
 
 
   | Single(_, ({name="string_of_int";_} as id),_ ),  "pervasives.ml" ->
-    Js_output.of_stmt @@ S.const_variable id ~exp:(E.runtime_ref
-                                                     Js_helper.prim "string_of_int")
+    Js_output.of_stmt @@ S.alias_variable id
+      ~exp:( 
+        let arg = Ext_ident.create "param" in
+        E.fun_ [arg] [S.return (E.anything_to_string (E.var arg))]
+      )
 
   | Single(_, ({name="max_float";_} as id),_ ),  "pervasives.ml" ->
 
-    Js_output.of_stmt @@ S.const_variable id 
+    Js_output.of_stmt @@ S.alias_variable id 
       ~exp:(E.js_global_dot "Number" "MAX_VALUE")
   | Single(_, ({name="min_float";_} as id) ,_ ), "pervasives.ml" ->
-    Js_output.of_stmt @@  S.const_variable id
+    Js_output.of_stmt @@  S.alias_variable id
       ~exp:(E.js_global_dot  "Number" "MIN_VALUE")
   | Single(_, ({name="epsilon_float";_} as id) ,_ ),  "pervasives.ml" ->
-    Js_output.of_stmt @@ S.const_variable id 
+    Js_output.of_stmt @@ S.alias_variable id 
       ~exp:(E.js_global_dot  "Number" "EPSILON")
   | Single(_, ({name="cat";_} as id) ,_ ),  "bytes.ml" ->
-    Js_output.of_stmt @@ S.const_variable id
-      ~exp:(E.runtime_ref
-              Js_helper.string "bytes_cat")
+    Js_output.of_stmt @@ S.alias_variable id
+      ~exp:(let a = Ext_ident.create "a" in 
+            let b = Ext_ident.create "b" in
+            E.fun_ [a;b] [S.return (E.array_append (E.var a) (E.var b))]
+           )
 
   (** Special handling for values in [Sys] *)
   | Single(_, ({name="max_array_length" | "max_string_length";_} as id) ,_ ),  "sys.ml" ->
     (* See [js_knowledge] Array size section, can not be expressed by OCaml int,
        note that casual handling of {!Sys.max_string_length} could result into 
        negative value which could cause wrong behavior of {!Buffer.create}
      *)
-    Js_output.of_stmt @@ S.const_variable id ~exp:(E.float "4_294_967_295.") 
+    Js_output.of_stmt @@ S.alias_variable id ~exp:(E.float "4_294_967_295.") 
 
   | Single(_, ({name="max_int";_} as id) ,_ ),  ("sys.ml" | "nativeint.ml") ->
     (* See [js_knowledge] Max int section, (2. ** 53. -. 1.;;) can not be expressed by OCaml int *)
-    Js_output.of_stmt @@ S.const_variable id ~exp:(E.float "9007199254740991.") 
+    Js_output.of_stmt @@ S.alias_variable id ~exp:(E.float "9007199254740991.") 
 
   | Single(_, ({name="min_int";_} as id) ,_ ),  ("sys.ml" | "nativeint.ml") ->
     (* See [js_knowledge] Max int section, -. (2. ** 53. -. 1.);; can not be expressed by OCaml int *)
-    Js_output.of_stmt @@ S.const_variable id ~exp:(E.float ("-9007199254740991.")) 
+    Js_output.of_stmt @@ S.alias_variable id ~exp:(E.float ("-9007199254740991.")) 
 
   | Single (kind, id, lam), _ -> 
     (* let lam = Optimizer.simplify_lets [] lam in  *)