flambda-backend: Persistent environment and reproducibility (ocaml#533)

debugger/command_line.ml

@@ -263,7 +263,7 @@ let instr_dir ppf lexbuf =
     if new_directory = [] then begin
       if yes_or_no "Reinitialize directory list" then begin
         Load_path.init !default_load_path;
-        Envaux.reset_cache ();
+        Envaux.reset_cache ~preserve_persistent_env:false;
         Hashtbl.clear Debugger_config.load_path_for;
         flush_buffer_list ()
         end

debugger/parameters.ml

@@ -34,7 +34,7 @@ let topdirs_path = ref (Filename.concat Config.standard_library "compiler-libs")
 
 let add_path dir =
   Load_path.add_dir dir;
-  Envaux.reset_cache()
+  Envaux.reset_cache ~preserve_persistent_env:false
 
 let add_path_for mdl dir =
   let old = try Hashtbl.find load_path_for mdl with Not_found -> [] in

debugger/program_management.ml

@@ -129,7 +129,7 @@ let initialize_loading () =
   Symbols.clear_symbols ();
   Symbols.read_symbols 0 !program_name;
   Load_path.init (Load_path.get_paths () @ !Symbols.program_source_dirs);
-  Envaux.reset_cache ();
+  Envaux.reset_cache ~preserve_persistent_env:false;
   if !debug_loading then
     prerr_endline "Opening a socket...";
   open_connection !socket_name

driver/compmisc.ml

@@ -32,7 +32,7 @@ let init_path ?(dir="") () =
   let exp_dirs =
     List.map (Misc.expand_directory Config.standard_library) dirs in
   Load_path.init (dir :: List.rev_append exp_dirs (Clflags.std_include_dir ()));
-  Env.reset_cache ()
+  Env.reset_cache ~preserve_persistent_env:false
 
 (* Return the initial environment in which compilation proceeds. *)
 

tools/ocamlcmt.ml

@@ -173,7 +173,7 @@ let main () =
           | Some "-" -> None
           | Some _ as x -> x
         in
-        Envaux.reset_cache ();
+        Envaux.reset_cache ~preserve_persistent_env:false;
         List.iter Load_path.add_dir cmt.cmt_loadpath;
         Cmt2annot.gen_annot target_filename
           ~sourcefile:cmt.cmt_sourcefile

typing/env.ml

@@ -858,9 +858,10 @@ let reset_declaration_caches () =
   Types.Uid.Tbl.clear !used_constructors;
   ()
 
-let reset_cache () =
+let reset_cache ~preserve_persistent_env =
   Current_unit_name.set "";
-  Persistent_env.clear !persistent_env;
+  if not preserve_persistent_env then
+    Persistent_env.clear !persistent_env;
   reset_declaration_caches ();
   ()
 

typing/env.mli

@@ -362,7 +362,7 @@ val add_lock : Types.value_mode -> t -> t
 val add_region_lock : t -> t
 
 (* Initialize the cache of in-core module interfaces. *)
-val reset_cache: unit -> unit
+val reset_cache: preserve_persistent_env:bool -> unit
 
 (* To be called before each toplevel phrase. *)
 val reset_cache_toplevel: unit -> unit

typing/envaux.ml

@@ -24,9 +24,9 @@ exception Error of error
 let env_cache =
   (Hashtbl.create 59 : ((Env.summary * Subst.t), Env.t) Hashtbl.t)
 
-let reset_cache () =
+let reset_cache ~preserve_persistent_env =
   Hashtbl.clear env_cache;
-  Env.reset_cache()
+  Env.reset_cache ~preserve_persistent_env
 
 let rec env_from_summary sum subst =
   try

typing/envaux.mli

@@ -22,7 +22,7 @@ val env_from_summary : Env.summary -> Subst.t -> Env.t
 
 (* Empty the environment caches. To be called when load_path changes. *)
 
-val reset_cache: unit -> unit
+val reset_cache: preserve_persistent_env:bool -> unit
 
 val env_of_only_summary : Env.t -> Env.t
 

typing/typemod.ml

@@ -2987,7 +2987,7 @@ let () =
         None
     )
 
-let reset () =
-  Env.reset_cache ();
-  Envaux.reset_cache ();
+let reset ~preserve_persistent_env =
+  Env.reset_cache ~preserve_persistent_env;
+  Envaux.reset_cache ~preserve_persistent_env;
   Typetexp.reset_type_variables ()

typing/typemod.mli

@@ -139,4 +139,4 @@ val report_error: Env.t -> formatter -> error -> unit
 
 (** Clear several bits of global state that may retain large amounts of memory
     after typechecking is finished. *)
-val reset : unit -> unit
+val reset : preserve_persistent_env:bool -> unit