Flag to generate the new exception handling instructions

Author: vouillon

compiler/bin-wasm_of_ocaml/compile.ml

@@ -84,6 +84,7 @@ let preprocessor_variables () =
         | `Disabled | `Jspi -> "jspi"
         | `Cps -> "cps"
         | `Double_translation -> assert false) )
+  ; "exnref", Wat_preprocess.Bool (Config.Flag.exnref ())
   ]
 
 let with_runtime_files ~runtime_wasm_files f =

compiler/bin-wasm_of_ocaml/gen/gen.ml

@@ -75,7 +75,7 @@ let check_js_file fname =
 (* Keep the two variables below in sync with function build_runtime in
    ../compile.ml *)
 
-let default_flags = []
+let default_flags = [ "exnref", `B false ]
 
 let interesting_runtimes = [ [ "effects", `S "jspi" ]; [ "effects", `S "cps" ] ]
 

compiler/lib-wasm/binaryen.ml

@@ -135,11 +135,11 @@ let optimize
     ~output_file
     () =
   command
-    ("wasm-opt"
-     :: (common_options ()
-        @ (match options with
-          | Some o -> o
-          | None -> optimization_options profile)
-        @ [ Filename.quote input_file; "-o"; Filename.quote output_file ])
+    (("wasm-opt" :: (if Config.Flag.exnref () then [ "--emit-exnref" ] else []))
+    @ common_options ()
+    @ (match options with
+      | Some o -> o
+      | None -> optimization_options profile)
+    @ [ Filename.quote input_file; "-o"; Filename.quote output_file ]
     @ opt_flag "--input-source-map" opt_input_sourcemap
     @ opt_flag "--output-source-map" opt_output_sourcemap)

compiler/lib/config.ml

@@ -106,6 +106,8 @@ module Flag = struct
   let es6 = o ~name:"es6" ~default:false
 
   let load_shapes_auto = o ~name:"load-shapes-auto" ~default:false
+
+  let exnref = o ~name:"exnref" ~default:false
 end
 
 module Param = struct

compiler/lib/config.mli

@@ -76,6 +76,8 @@ module Flag : sig
 
   val load_shapes_auto : unit -> bool
 
+  val exnref : unit -> bool
+
   val enable : string -> unit
 
   val disable : string -> unit