Wat file preprocessor

Author: vouillon

compiler/bin-wasm_of_ocaml/compile.ml

@@ -90,7 +90,9 @@ let with_runtime_files ~runtime_wasm_files f =
 
 let build_runtime ~runtime_file =
   (* Keep this variables in sync with gen/gen.ml *)
-  let variables = [] in
+  let variables =
+    [ "wasi", Config.Flag.wasi (); "trap-on-exception", Config.Flag.trap_on_exception () ]
+  in
   match
     List.find_opt Runtime_files.precompiled_runtimes ~f:(fun (flags, _) ->
         assert (
@@ -107,7 +109,9 @@ let build_runtime ~runtime_file =
             ; file = module_name ^ ".wat"
             ; source = Contents contents
             })
-          Runtime_files.wat_files
+          (if Config.Flag.wasi ()
+           then ("libc", Runtime_files.wasi_libc) :: Runtime_files.wat_files
+           else Runtime_files.wat_files)
       in
       Runtime.build
         ~link_options:[ "-g" ]

compiler/bin-wasm_of_ocaml/dune

@@ -27,6 +27,9 @@
   gen/gen.exe
   ../../runtime/wasm/runtime.js
   ../../runtime/wasm/deps.json
+  ../../runtime/wasm/runtime-wasi.js
+  ../../runtime/wasm/deps-wasi.json
+  ../../runtime/wasm/libc.wasm
   (glob_files ../../runtime/wasm/*.wat)
   (glob_files ../../runtime/wasm/runtime-*.wasm))
  (action

compiler/bin-wasm_of_ocaml/gen/gen.ml

@@ -3,9 +3,9 @@ let read_file ic = really_input_string ic (in_channel_length ic)
 (* Keep the two variables below in sync with function build_runtime in
    ../compile.ml *)
 
-let default_flags = []
+let default_flags = [ "trap-on-exception", false ]
 
-let interesting_runtimes = [ [] ]
+let interesting_runtimes = [ [ "wasi", false ]; [ "wasi", true ] ]
 
 let name_runtime l =
   let flags = List.filter_map (fun (k, v) -> if v then Some k else None) l in
@@ -30,10 +30,19 @@ let () =
   Format.printf
     "let dependencies = \"%s\"@."
     (String.escaped (read_file (open_in_bin Sys.argv.(2))));
+  Format.printf
+    "let js_wasi_launcher = \"%s\"@."
+    (String.escaped (read_file (open_in_bin Sys.argv.(3))));
+  Format.printf
+    "let wasi_dependencies = \"%s\"@."
+    (String.escaped (read_file (open_in_bin Sys.argv.(4))));
+  Format.printf
+    "let wasi_libc = \"%s\"@."
+    (String.escaped (read_file (open_in_bin Sys.argv.(5))));
   let wat_files, runtimes =
     List.partition
       (fun f -> Filename.check_suffix f ".wat")
-      (Array.to_list (Array.sub Sys.argv 3 (Array.length Sys.argv - 3)))
+      (Array.to_list (Array.sub Sys.argv 6 (Array.length Sys.argv - 6)))
   in
   Format.printf
     "let wat_files = [%a]@."

compiler/lib-wasm/wat_preprocess.ml

@@ -407,6 +407,32 @@ let rec rewrite_list st l = List.iter ~f:(rewrite st) l
 
 and rewrite st elt =
   match elt with
+  | { desc =
+        List
+          ({ desc = Atom "try"; _ }
+          :: ( { desc = List ({ desc = Atom "result"; _ } :: _); _ }
+               :: { desc = List ({ desc = Atom "do"; loc = _, pos_after_do } :: body)
+                  ; loc = _, pos_after_body
+                  }
+               :: _
+             | { desc = List ({ desc = Atom "do"; loc = _, pos_after_do } :: body)
+               ; loc = _, pos_after_body
+               }
+               :: _ ))
+    ; loc = pos, pos'
+    }
+    when false (*ZZZ StringMap.find "trap-on-exception" st.variables*) ->
+      write st pos;
+      Buffer.add_string st.buf "(block";
+      skip st pos_after_do;
+      rewrite_list st body;
+      write st pos_after_body;
+      skip st pos'
+  | { desc = List ({ desc = Atom "throw"; _ } :: _); loc = pos, pos' }
+    when false (*ZZZ StringMap.find "trap-on-exception" st.variables*) ->
+      write st pos;
+      Buffer.add_string st.buf "(unreachable)";
+      skip st pos'
   | { desc =
         List
           [ { desc = Atom "@if"; _ }

runtime/wasm/dune

@@ -16,6 +16,22 @@
    ../../compiler/bin-wasm_of_ocaml/wasmoo_link_wasm.exe
    --binaryen=-g
    --binaryen-opt=-O3
+   --disable wasi
+   %{target}
+   %{read-lines:args})))
+
+(rule
+ (target runtime-wasi.wasm)
+ (deps
+  args
+  (glob_files *.wat))
+ (action
+  (run
+   wasmoo_util
+   link
+   --binaryen=-g
+   --binaryen-opt=-O3
+   --enable wasi
    %{target}
    %{read-lines:args})))