Compiler: fix for 12430

compiler/lib-dynlink/js_of_ocaml_compiler_dynlink.ml

@@ -12,13 +12,36 @@ type bytecode_sections =
 
 external get_bytecode_sections : unit -> bytecode_sections = "jsoo_get_bytecode_sections"
 
+let normalize_bytecode code =
+  match Ocaml_version.v with
+  | `V4_08
+  | `V4_09
+  | `V4_10
+  | `V4_11
+  | `V4_12
+  | `V4_13
+  | `V4_14
+  | `V5_00
+  | `V5_01
+  | `V5_02 -> code
+  | `V5_03 ->
+      (* starting with ocaml 5.3. The toplevel no longer append [RETURN 1] *)
+      let { Instr.opcode; _ } = Instr.find RETURN in
+      let len = String.length code in
+      let b = Bytes.create (len + 8) in
+      Bytes.blit_string ~src:code ~src_pos:0 ~dst:b ~dst_pos:0 ~len;
+      Bytes.set_int32_le b len (Int32.of_int opcode);
+      Bytes.set_int32_le b (len + 4) 1l;
+      Bytes.to_string b
+
 let () =
   let global = J.pure_js_expr "globalThis" in
   Config.Flag.set "use-js-string" (Jsoo_runtime.Sys.Config.use_js_string ());
   Config.Flag.set "effects" (Jsoo_runtime.Sys.Config.effects ());
   (* this needs to stay synchronized with toplevel.js *)
   let toplevel_compile (s : string) (debug : Instruct.debug_event list array) :
       unit -> J.t =
+    let s = normalize_bytecode s in
     let prims = Array.of_list (Ocaml_compiler.Symtable.all_primitives ()) in
     let b = Buffer.create 100 in
     let fmt = Pretty_print.to_buffer b in

compiler/lib/instr.ml

@@ -367,6 +367,11 @@ let ops =
   in
   ops
 
+let find i =
+  match Array.find_opt ~f:(fun { code; _ } -> Poly.(i = code)) ops with
+  | None -> assert false
+  | Some x -> x
+
 let get code i = Char.code code.[i]
 
 let getu code pc =

compiler/lib/instr.mli

@@ -197,6 +197,8 @@ type desc =
   ; opcode : int
   }
 
+val find : t -> desc
+
 val get_instr_exn : string -> int -> desc
 
 val gets : string -> int -> int