Accept command line options via environment vars

Summary:public
Generalize command line option parsing to query an environment variable
for args, and then parse the environment and command line arguments.

Each executable uses a distinct environment variable:
  - InferAnalyze:   INFER_ARGS
  - InferJava:      INFERJAVA_ARGS
  - InferClang:     INFERCLANG_ARGS
  - InferLLVM:      INFERLLVM_ARGS
  - checkCopyright: CHECKCOPYRIGHT_ARGS

For now these variables need to be set manually.  So the usability is
still pretty bad, but is a step in the direction of enabling debugging
the analyzer on code built with buck.

Reviewed By: cristianoc, martinoluca

Differential Revision: D2987288

fb-gh-sync-id: f477611
shipit-source-id: f477611

infer/src/backend/inferanalyze.ml

@@ -223,7 +223,7 @@ let print_usage_exit () =
 let () = (* parse command-line arguments *)
   let f _ =
     () (* ignore anonymous arguments *) in
-  Arg.parse arg_desc f usage;
+  Arg.parse "INFER_ARGS" arg_desc f usage;
   if not (Sys.file_exists !Config.results_dir) then
     begin
       L.err "ERROR: results directory %s does not exist@.@." !Config.results_dir;

infer/src/backend/inferprint.ml

@@ -1023,7 +1023,7 @@ module AnalysisResults = struct
       if not (Filename.check_suffix arg ".specs") && arg <> "."
       then print_usage_exit "arguments must be .specs files"
       else args := arg::!args in
-    Arg.parse arg_desc f usage;
+    Arg.parse "INFERPRINT_ARGS" arg_desc f usage;
     if !test_filtering then
       begin
         Inferconfig.test ();

infer/src/backend/utils.ml

@@ -857,6 +857,19 @@ module Arg = struct
       ("", Arg.Unit (fun () -> ()), " \n  " ^ title ^ "\n") ::
       IList.sort (fun (x, _, _) (y, _, _) -> Pervasives.compare x y) unsorted_desc' in
     align dlist
+
+  let env_to_argv env =
+    Str.split (Str.regexp ":") env
+
+  let prepend_to_argv args =
+    let cl_args = match Array.to_list Sys.argv with _ :: tl -> tl | [] -> [] in
+    Sys.executable_name :: args @ cl_args
+
+  let parse env_var spec anon usage =
+    let env_args = env_to_argv (try Unix.getenv env_var with Not_found -> "") in
+    let env_cl_args = prepend_to_argv env_args in
+    Arg.parse_argv (Array.of_list env_cl_args) spec anon usage
+
 end
 
 (** flags for a procedure *)

infer/src/backend/utils.mli

@@ -233,7 +233,12 @@ module Arg : sig
 
   val align : (key * spec * doc) list -> aligned list
 
-  val parse : aligned list -> anon_fun -> usage_msg -> unit
+  (** [parse env_var arg_desc anon_fun usage_msg] prepends the decoded value of environment variable
+      [env_var] to [Sys.argv] and then parses the result using the standard [Arg.parse].  Therefore
+      arguments passed on the command line supercede those specified in the environment variable.
+      WARNING: If an argument appears both in the environment variable and on the command line, it
+      will be interpreted twice. *)
+  val parse : string -> aligned list -> anon_fun -> usage_msg -> unit
 
   val usage : aligned list -> usage_msg -> unit
 

infer/src/clang/cMain.ml

@@ -96,9 +96,6 @@ let print_usage_exit () =
   Arg.usage arg_desc usage;
   exit(1)
 
-let () =
-  Arg.parse arg_desc (fun _ -> ()) usage
-
 let buffer_len = 16384
 
 (* This function reads the json file in fname, validates it, and encoded in the AST data structure*)
@@ -138,7 +135,8 @@ let do_run source_path ast_path =
     (Yojson.Json_error s) as exc -> Printing.log_err "%s\n" s;
       raise exc
 
-let _ =
+let () =
+  Arg.parse "INFERCLANG_ARGS" arg_desc (fun _ -> ()) usage ;
   Config.print_types := true;
   if Option.is_none !CFrontend_config.source_file then
     (Printing.log_err "Incorrect command line arguments\n";

infer/src/java/jMain.ml

@@ -78,7 +78,7 @@ let print_usage_exit () =
   exit(1)
 
 let () =
-  Arg.parse arg_desc (fun _ -> ()) usage;
+  Arg.parse "INFERJAVA_ARGS" arg_desc (fun _ -> ()) usage;
   if Config.analyze_models && !JClasspath.models_jar <> "" then
     failwith "Not expecting model file when analyzing the models";
   if not Config.analyze_models && !JClasspath.models_jar = "" then

infer/src/llvm/lMain.ml

@@ -67,7 +67,7 @@ let store_tenv tenv =
   Sil.store_tenv_to_file tenv_filename tenv
 
 let () =
-  Arg.parse arg_desc (fun _ -> ()) usage;
+  Arg.parse "INFERLLVM_ARGS" arg_desc (fun _ -> ()) usage;
   begin match !LConfig.source_filename with
     | None -> print_usage_exit ()
     | Some source_filename -> init_global_state source_filename

infer/src/scripts/checkCopyright.ml

@@ -275,6 +275,6 @@ let () =
   let to_check = ref [] in
   let add_file_to_check fname =
     to_check := fname :: !to_check in
-  Arg.parse (Arg.align speclist) add_file_to_check usage_msg;
+  Arg.parse "CHECKCOPYRIGHT_ARGS" (Arg.align speclist) add_file_to_check usage_msg;
   IList.iter check_copyright (IList.rev !to_check);
   exit 0