adding Const_module_alias

- we keep it different from Const_js_undefined mostly because we don't want to serialize  module alias in cmj format

Author: bobzhang

jscomp/core/lam.ml

@@ -721,6 +721,7 @@ let if_ (a : t) (b : t) (c : t) : t =
         if x <> 0n then b else c
       | Const_js_false
       | Const_js_null
+      | Const_module_alias
       | Const_js_undefined -> c
       | Const_js_true
       | Const_string _

jscomp/core/lam_analysis.ml

@@ -324,7 +324,7 @@ and size_constant x =
   | Const_nativeint _ 
   | Const_immstring _
   | Const_pointer _ 
-  | Const_js_null | Const_js_undefined
+  | Const_js_null | Const_js_undefined | Const_module_alias
   | Const_js_true | Const_js_false
     -> 1 
   | Const_unicode _  (* TODO: this seems to be not good heurisitives*)

jscomp/core/lam_compile_const.ml

@@ -35,6 +35,7 @@ module E = Js_exp_make
 let rec is_some_none_aux (x : Lam_constant.t) acc = 
   match x with 
   | Const_some v -> is_some_none_aux v (acc + 1)
+  | Const_module_alias
   | Const_js_undefined -> acc 
   | _ -> -1
 
@@ -50,6 +51,7 @@ translate_some (x : Lam_constant.t) : J.expression =
   else nested_some_none depth (E.optional_block (translate Const_js_undefined))
 and translate (x : Lam_constant.t ) : J.expression = 
   match x with 
+  | Const_module_alias -> E.undefined (*  TODO *)
   | Const_some s ->  translate_some s   
   | Const_js_true -> E.bool true 
   | Const_js_false -> E.bool false

jscomp/core/lam_compile_util.ml

@@ -62,10 +62,10 @@ let comment_of_tag_info  (x : Lam_tag_info.t) =
   | Blk_extension_slot -> None
   | Blk_na s -> if s = "" then None else Some s
 
-let module_alias = Some "alias"  
+(* let module_alias = Some "alias"   *)
 let comment_of_pointer_info (x :  Lam_pointer_info.t)= 
   match x with 
   | Pt_constructor {name;_}
   | Pt_variant {name} -> Some name
-  | Pt_module_alias -> module_alias
+  (* | Pt_module_alias -> module_alias *)
   | Pt_na -> None

jscomp/core/lam_constant.ml

@@ -40,13 +40,15 @@
   | Const_float_array of string list
   | Const_immstring of string
   | Const_some of t 
+  | Const_module_alias 
     (* eventually we can remove it, since we know
       [constant] is [undefined] or not 
     *) 
 
 
 let rec eq_approx (x : t) (y : t) = 
   match x with 
+  | Const_module_alias -> y = Const_module_alias
   | Const_js_null -> y = Const_js_null
   | Const_js_undefined -> y =  Const_js_undefined
   | Const_js_true -> y = Const_js_true

jscomp/core/lam_constant.mli

@@ -43,5 +43,6 @@ type t =
     (* eventually we can remove it, since we know
       [constant] is [undefined] or not 
     *) 
+  | Const_module_alias  
 val eq_approx : t -> t -> bool
 val lam_none : t   

jscomp/core/lam_constant_convert.ml

@@ -44,7 +44,7 @@ let rec convert_constant ( const : Lambda.structured_constant) : Lam_constant.t
     begin match p with 
     | Pt_constructor {name;cstrs} -> Const_pointer(i, Pt_constructor {name; cstrs})
     | Pt_variant {name} -> Const_pointer(i,Pt_variant {name})
-    | Pt_module_alias -> Const_pointer(i, Pt_module_alias)
+    | Pt_module_alias -> Const_module_alias
     | Pt_builtin_boolean -> if i = 0 then Const_js_false else Const_js_true
     | Pt_shape_none ->
        Lam_constant.lam_none

jscomp/core/lam_pointer_info.ml

@@ -26,5 +26,5 @@
 type t = 
   | Pt_constructor of {name : string ; cstrs : int * int}
   | Pt_variant of {name : string }
-  | Pt_module_alias
+  (* | Pt_module_alias *)
   | Pt_na 

jscomp/core/lam_pointer_info.mli

@@ -26,5 +26,5 @@
 type t = 
   | Pt_constructor of {name : string ; cstrs : int * int}
   | Pt_variant of { name : string}
-  | Pt_module_alias
+  (* | Pt_module_alias *)
   | Pt_na 

jscomp/core/lam_print.ml

@@ -22,6 +22,7 @@ let rec struct_const ppf (cst : Lam_constant.t) =
   | Const_js_true -> fprintf ppf "#true"
   | Const_js_false -> fprintf ppf "#false"
   | Const_js_null -> fprintf ppf "#null"
+  | Const_module_alias -> fprintf ppf "#alias"
   | Const_js_undefined -> fprintf ppf "#undefined"
   |  (Const_int n) -> fprintf ppf "%i" n
   |  (Const_char c) -> fprintf ppf "%C" c

jscomp/core/lam_stats_export.ml

@@ -100,7 +100,7 @@ let values_of_export
          in 
        match arity, persistent_closed_lambda with 
        | Single Arity_na, 
-        (None | Some (Lconst (Const_pointer (_, Pt_module_alias)))) -> acc
+        (None | Some (Lconst Const_module_alias)) -> acc
        | Submodule [||], None -> acc          
        | _ ->  
          let cmj_value : Js_cmj_format.cmj_value =