semantic logging in lib_base

AMENDED: Syn has always been DSL, Semantic has always been
Make_semantic.

src/lib_base/base_logging.ml

@@ -7,4 +7,13 @@
 (*                                                                        *)
 (**************************************************************************)
 
-include Tezos_stdlib.Logging.Make(struct let name = "base" end)
+include Tezos_stdlib.Logging.Make_semantic(struct let name = "base" end)
+
+let pp_exn_trace ppf backtrace =
+  if String.length backtrace <> 0 then
+    Format.fprintf ppf
+      "@,Backtrace:@,  @[<h>%a@]"
+      Format.pp_print_text backtrace
+
+let pid = Tag.def ~doc:"unix process ID where problem occurred" "pid" Format.pp_print_int
+let exn_trace = Tag.def ~doc:"backtrace from native Ocaml exception" "exn_trace" pp_exn_trace

src/lib_base/base_logging.mli

@@ -7,4 +7,7 @@
 (*                                                                        *)
 (**************************************************************************)
 
-include Tezos_stdlib.Logging.LOG
+include Tezos_stdlib.Logging.SEMLOG
+
+val pid : int Tag.def
+val exn_trace : string Tag.def

src/lib_base/lwt_exit.ml

@@ -16,19 +16,12 @@ let () =
   Lwt.async_exception_hook :=
     (function
       | Exit -> ()
-      | exn ->
+      | e ->
           let backtrace = Printexc.get_backtrace () in
-          Base_logging.fatal_error "@[<v 2>%a%a@]"
-            (fun ppf exn ->
-               Format.fprintf ppf
-                 "@[Uncaught (asynchronous) exception (%d):@ %a@]"
-                 (Unix.getpid ())
-                 Error_monad.pp_exn exn)
-            exn
-            (fun ppf backtrace ->
-               if String.length backtrace <> 0 then
-                 Format.fprintf ppf
-                   "@,Backtrace:@,  @[<h>%a@]"
-                   Format.pp_print_text backtrace)
-            backtrace ;
+          Base_logging.(fatal_error Tag.DSL.(fun f ->
+              f "@[<v 2>@[Uncaught (asynchronous) exception (%d):@ %a@]%a@]"
+              -% t event "uncaught_async_exception"
+              -% s pid (Unix.getpid ())
+              -% a exn e
+              -% a exn_trace backtrace)) ;
           Lwt.wakeup exit_wakener 1)