Add skeleton for import.

Goes from the front-end all the way to where the primitive should be handled in the back-end, and prints a dump of the back-end expression.

Author: cristianoc

jscomp/core/lam_analysis.ml

@@ -46,10 +46,10 @@ let rec no_side_effects (lam : Lam.t) : bool =
               ( "?int64_float_of_bits"
               (* more safe to check if arguments are constant *)
               (* non-observable side effect *)
-              | "?sys_get_argv" (* should be fine *)
-              | "?string_repeat" | "?make_vect" | "?create_bytes" | "?obj_dup"
-              | "caml_array_dup" | "?nativeint_add" | "?nativeint_div"
-              | "?nativeint_mod" | "?nativeint_lsr" | "?nativeint_mul" ),
+              | "?sys_get_argv" (* should be fine *) | "?string_repeat"
+              | "?make_vect" | "?create_bytes" | "?obj_dup" | "caml_array_dup"
+              | "?nativeint_add" | "?nativeint_div" | "?nativeint_mod"
+              | "?nativeint_lsr" | "?nativeint_mul" ),
               _ ) ->
               true
           | _, _ -> false)
@@ -58,9 +58,9 @@ let rec no_side_effects (lam : Lam.t) : bool =
           | [ _; Lconst cst ] -> not_zero_constant cst
           | _ -> false)
       | Pcreate_extension _ | Pjs_typeof | Pis_null | Pis_not_none | Psome
-      | Psome_not_nest | Pis_undefined | Pis_null_undefined | Pnull_to_opt
-      | Pundefined_to_opt | Pnull_undefined_to_opt | Pjs_fn_make _
-      | Pjs_object_create _
+      | Psome_not_nest | Pis_undefined | Pis_null_undefined | Pimport
+      | Pnull_to_opt | Pundefined_to_opt | Pnull_undefined_to_opt
+      | Pjs_fn_make _ | Pjs_object_create _
       (* TODO: check *)
       | Pbytes_to_string | Pmakeblock _
       (* whether it's mutable or not *)
@@ -87,9 +87,8 @@ let rec no_side_effects (lam : Lam.t) : bool =
       | Pasrint64 | Pint64comp _
       (* Operations on big arrays: (unsafe, #dimensions, kind, layout) *)
       (* Compile time constants *)
-      | Pctconst _ (* Integer to external pointer *)
-      | Poffsetint _ | Pstringadd | Pjs_function_length | Pcaml_obj_length
-      | Pwrap_exn
+      | Pctconst _ (* Integer to external pointer *) | Poffsetint _ | Pstringadd
+      | Pjs_function_length | Pcaml_obj_length | Pwrap_exn
       | Praw_js_code
           {
             code_info =
@@ -197,8 +196,7 @@ and size_constant x =
   | Const_js_null | Const_js_undefined | Const_module_alias | Const_js_true
   | Const_js_false ->
       1
-  | Const_string _ ->
-      1
+  | Const_string _ -> 1
   | Const_some s -> size_constant s
   | Const_block (_, _, str) ->
       Ext_list.fold_left str 0 (fun acc x -> acc + size_constant x)
@@ -211,7 +209,6 @@ let args_all_const (args : Lam.t list) =
   Ext_list.for_all args (fun x -> match x with Lconst _ -> true | _ -> false)
 
 let exit_inline_size = 7
-
 let small_inline_size = 5
 
 (** destruct pattern will work better 

jscomp/core/lam_compile_primitive.ml

@@ -78,6 +78,14 @@ let translate loc (cxt : Lam_compile_context.t) (prim : Lam_primitive.t)
           | _ -> E.runtime_call Js_runtime_modules.option "nullable_to_opt" args
           )
       | _ -> assert false)
+  | Pimport -> (
+      match args with
+      | [ e ] -> (
+          match e.expression_desc with
+          | _ ->
+              let d = Js_dump.string_of_expression e in
+              E.str ("TODO:import " ^ d) )
+      | _ -> assert false)
   | Pjs_function_length -> E.function_length (Ext_list.singleton_exn args)
   | Pcaml_obj_length -> E.obj_length (Ext_list.singleton_exn args)
   | Pis_null -> E.is_null (Ext_list.singleton_exn args)
@@ -301,7 +309,8 @@ let translate loc (cxt : Lam_compile_context.t) (prim : Lam_primitive.t)
       | Backend_type ->
           E.make_block E.zero_int_literal
             (Blk_constructor { name = "Other"; num_nonconst = 1; tag = 0 })
-            [ E.str "BS" ] Immutable)
+            [ E.str "BS" ]
+            Immutable)
   | Pduprecord -> Lam_dispatch_primitive.translate loc "?obj_dup" args
   | Plazyforce
   (* FIXME: we don't inline lazy force or at least

jscomp/core/lam_convert.ml

@@ -480,6 +480,7 @@ let convert (exports : Set_ident.t) (lam : Lambda.lambda) :
           | "#nullable_to_opt" -> Pnull_undefined_to_opt
           | "#null_to_opt" -> Pnull_to_opt
           | "#is_nullable" -> Pis_null_undefined
+          | "#import" -> Pimport
           | "#string_append" -> Pstringadd
           | "#wrap_exn" -> Pwrap_exn
           | "#obj_length" -> Pcaml_obj_length

jscomp/core/lam_primitive.ml

@@ -142,6 +142,7 @@ type t =
   | Pis_null
   | Pis_undefined
   | Pis_null_undefined
+  | Pimport
   | Pjs_typeof
   | Pjs_function_length
   | Pcaml_obj_length
@@ -218,6 +219,7 @@ let eq_primitive_approx (lhs : t) (rhs : t) =
   | Psome_not_nest -> rhs = Psome_not_nest
   | Pis_undefined -> rhs = Pis_undefined
   | Pis_null_undefined -> rhs = Pis_null_undefined
+  | Pimport -> rhs = Pimport
   | Pjs_typeof -> rhs = Pjs_typeof
   | Pisint -> rhs = Pisint
   | Pis_poly_var_block -> rhs = Pis_poly_var_block

jscomp/core/lam_primitive.mli

@@ -130,6 +130,7 @@ type t =
   | Pis_null
   | Pis_undefined
   | Pis_null_undefined
+  | Pimport
   | Pjs_typeof
   | Pjs_function_length
   | Pcaml_obj_length

jscomp/core/lam_print.ml

@@ -78,6 +78,7 @@ let primitive ppf (prim : Lam_primitive.t) =
   | Pval_from_option_not_nest -> fprintf ppf "[?unbox-not-nest]"
   | Pis_undefined -> fprintf ppf "[?undefined]"
   | Pis_null_undefined -> fprintf ppf "[?null?undefined]"
+  | Pimport -> fprintf ppf "[import]"
   | Pmakeblock (tag, _, Immutable) -> fprintf ppf "makeblock %i" tag
   | Pmakeblock (tag, _, Mutable) -> fprintf ppf "makemutable %i" tag
   | Pfield (n, field_info) -> (