Start function: directly generate wasm code

compiler/lib/wasm/wa_generate.ml

@@ -1243,3 +1243,8 @@ let output ch ~context ~debug =
       let module G = Generate (Wa_gc_target) in
       let fields = G.output ~context in
       Wa_wat_output.f ~debug ch fields
+
+let wasm_output ch ~context =
+  let module G = Generate (Wa_gc_target) in
+  let fields = G.output ~context in
+  Wa_wasm_output.f ch fields

compiler/lib/wasm/wa_generate.mli

@@ -19,3 +19,5 @@ val output :
   -> context:Wa_code_generation.context
   -> debug:Parse_bytecode.Debug.t
   -> unit
+
+val wasm_output : out_channel -> context:Wa_code_generation.context -> unit

compiler/lib/wasm/wa_link.ml

@@ -281,24 +281,11 @@ let read_info z = info_from_sexp (Sexp.from_string (Zip.read_entry z ~name:"info
 
 let generate_start_function ~to_link ~out_file =
   let t1 = Timer.make () in
-  Fs.gen_file out_file
-  @@ fun wasm_file ->
-  let wat_file = Filename.chop_extension out_file ^ ".wat" in
-  (Filename.gen_file wat_file
+  Filename.gen_file out_file
   @@ fun ch ->
   let context = Wa_generate.start () in
   Wa_generate.add_init_function ~context ~to_link:("prelude" :: to_link);
-  Wa_generate.output
-    ch
-    ~context
-    ~debug:(Parse_bytecode.Debug.create ~include_cmis:false false));
-  Wa_binaryen.optimize
-    ~profile:(Driver.profile 1)
-    ~opt_input_sourcemap:None
-    ~opt_output_sourcemap:None
-    ~opt_sourcemap_url:None
-    ~input_file:wat_file
-    ~output_file:wasm_file;
+  Wa_generate.wasm_output ch ~context;
   if times () then Format.eprintf "    generate start: %a@." Timer.print t1
 
 let output_js js =