[config] better way to refer to the toplevel results dir

Summary:
The same logic for reading the env var and defaulting to the local
results dir was duplicated in a bunch of places.

Reviewed By: artempyanykh

Differential Revision: D16458976

fbshipit-source-id: 41f1a4f9c

infer/src/base/Config.ml

@@ -2485,9 +2485,7 @@ let inferconfig_file =
 
 
 let post_parsing_initialization command_opt =
-  if CommandLineOption.is_originator then (
-    (* let subprocesses know where the toplevel process' results dir is *)
-    Unix.putenv ~key:infer_top_results_dir_env_var ~data:!results_dir ;
+  if CommandLineOption.is_originator then
     (* make sure subprocesses read from the same .inferconfig as the toplevel process *)
     Option.iter inferconfig_file ~f:(fun filename ->
         let abs_filename =
@@ -2496,7 +2494,7 @@ let post_parsing_initialization command_opt =
             CLOpt.init_work_dir ^/ filename
           else filename
         in
-        Unix.putenv ~key:CommandDoc.inferconfig_env_var ~data:abs_filename ) ) ;
+        Unix.putenv ~key:CommandDoc.inferconfig_env_var ~data:abs_filename ) ;
   ( match !version with
   | `Full when !buck ->
       (* Buck reads stderr in some versions, stdout in others *)
@@ -3293,3 +3291,10 @@ let is_in_custom_symbols list_name symbol =
 
 
 let execution_id = Random.self_init () ; Random.int64 Int64.max_value
+
+let toplevel_results_dir =
+  if CLOpt.is_originator then (
+    (* let subprocesses know where the toplevel process' results dir is *)
+    Unix.putenv ~key:infer_top_results_dir_env_var ~data:results_dir ;
+    results_dir )
+  else Sys.getenv infer_top_results_dir_env_var |> Option.value ~default:results_dir

infer/src/base/Config.mli

@@ -99,8 +99,6 @@ val idempotent_getters : bool
 
 val infer_py_argparse_error_exit_code : int
 
-val infer_top_results_dir_env_var : string
-
 val initial_analysis_time : float
 
 val ivar_attributes : string
@@ -687,6 +685,12 @@ val threadsafe_aliases : Yojson.Basic.t
 
 val topl_properties : string list
 
+val toplevel_results_dir : string
+(** In some integrations, eg Buck, infer subprocesses started by the build system (started by the
+    toplevel infer process) will have their own results directory; this points to the results
+    directory of the toplevel infer process, which can be useful for, eg, storing debug info. In
+    other cases this is equal to {!results_dir}. *)
+
 val trace_error : bool
 
 val trace_events : bool

infer/src/base/EventLogger.ml

@@ -11,10 +11,7 @@ module CLOpt = CommandLineOption
 module IO = struct
   let log_file_extension = ".log"
 
-  let events_dir =
-    Option.value (Sys.getenv Config.infer_top_results_dir_env_var) ~default:Config.results_dir
-    ^/ Config.events_dir_name
-
+  let events_dir = Config.toplevel_results_dir ^/ Config.events_dir_name
 
   let out_chan = ref None
 

infer/src/base/Logging.ml

@@ -320,14 +320,9 @@ let setup_log_file () =
       ()
   | None ->
       let fmt, chan, preexisting_logfile =
-        let results_dir =
-          (* if invoked in a sub-dir (e.g., in Buck integrations), log inside the original log
-              file *)
-          Sys.getenv Config.infer_top_results_dir_env_var
-          |> Option.value ~default:Config.results_dir
-        in
+        (* if invoked in a sub-dir (e.g., in Buck integrations), log inside the original log file *)
         (* assumes the results dir exists already *)
-        let logfile_path = results_dir ^/ Config.log_file in
+        let logfile_path = Config.toplevel_results_dir ^/ Config.log_file in
         let preexisting_logfile = PolyVariantEqual.( = ) (Sys.file_exists logfile_path) `Yes in
         let chan = Pervasives.open_out_gen [Open_append; Open_creat] 0o666 logfile_path in
         let file_fmt =

infer/src/base/Memcached.ml

@@ -11,9 +11,7 @@ module L = Logging
 let memcached_socket_relative = "memcached.socket"
 
 (** find the results_dir of the top-level infer process *)
-let results_dir =
-  Sys.getenv Config.infer_top_results_dir_env_var |> Option.value ~default:Config.results_dir
-
+let results_dir = Config.toplevel_results_dir
 
 (** log file for memcached *)
 let memcached_log = results_dir ^ "/memcached.log"
@@ -26,8 +24,8 @@ let shell = "sh"
 
 type server = {input: In_channel.t; output: Out_channel.t}
 
-(* Unix socket paths have a historical length limit of ~100 chars (!?*@&*$).  However, this applies 
-   to the argument passed in the system call to create the socket.  Thus a workaround is to cd into 
+(* Unix socket paths have a historical length limit of ~100 chars (!?*@&*$).  However, this applies
+   to the argument passed in the system call to create the socket.  Thus a workaround is to cd into
    the parent dir of the socket and then create it, hence this function. *)
 let in_results_dir ~f =
   let cwd = Unix.getcwd () in

infer/src/base/PerfEvent.ml

@@ -224,13 +224,8 @@ let register_gc_stats logger =
 let logger =
   lazy
     (let log_file =
-       let results_dir =
-         (* if invoked in a sub-dir (e.g., in Buck integrations), log inside the original log
-              file *)
-         Sys.getenv Config.infer_top_results_dir_env_var
-         |> Option.value ~default:Config.results_dir
-       in
-       results_dir ^/ Config.trace_events_file
+       (* if invoked in a sub-dir (e.g., in Buck integrations), log inside the original log file *)
+       Config.toplevel_results_dir ^/ Config.trace_events_file
      in
      let is_toplevel_process = CommandLineOption.is_originator && not !ProcessPoolState.in_child in
      ( if is_toplevel_process then