extract functionality in new module for documentation

Summary:
`RegisterCheckers` is now doing a bunch of work to convert the new-style
checkers to the good old Callbacks datatypes. Extract the conversion
code into another module before more is added. A good opportunity to
document them.

Reviewed By: ezgicicek

Differential Revision: D21401817

fbshipit-source-id: 4cba3aa7b

infer/src/backend/CallbackOfChecker.ml

@@ -0,0 +1,54 @@
+(*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *)
+
+open! IStd
+
+(* make sure callbacks are set or the checkers will not be able to call into them (and get a nice
+   crash) *)
+let () =
+  AnalysisCallbacks.set_callbacks
+    { get_proc_desc_f= Ondemand.get_proc_desc
+    ; html_debug_new_node_session_f= NodePrinter.with_session
+    ; proc_resolve_attributes_f= Summary.OnDisk.proc_resolve_attributes }
+
+
+let interprocedural payload_field checker {Callbacks.summary; exe_env} =
+  let analyze_dependency proc_name =
+    let summary = Ondemand.analyze_proc_name ~caller_summary:summary proc_name in
+    Option.bind summary ~f:(fun {Summary.payloads; proc_desc; _} ->
+        Field.get payload_field payloads |> Option.map ~f:(fun payload -> (proc_desc, payload)) )
+  in
+  let analyze_pdesc_dependency proc_desc =
+    let summary = Ondemand.analyze_proc_desc ~caller_summary:summary proc_desc in
+    Option.bind summary ~f:(fun {Summary.payloads; _} ->
+        Field.get payload_field payloads |> Option.map ~f:(fun payload -> payload) )
+  in
+  let stats = ref summary.Summary.stats in
+  let update_stats ?add_symops ?failure_kind () =
+    stats := Summary.Stats.update ?add_symops ?failure_kind !stats
+  in
+  let result =
+    checker
+      { InterproceduralAnalysis.proc_desc= Summary.get_proc_desc summary
+      ; tenv= Exe_env.get_tenv exe_env (Summary.get_proc_name summary)
+      ; err_log= Summary.get_err_log summary
+      ; exe_env
+      ; analyze_dependency
+      ; analyze_pdesc_dependency
+      ; update_stats }
+  in
+  {summary with payloads= Field.fset payload_field summary.payloads result; stats= !stats}
+
+
+let interprocedural_file payload_field checker {Callbacks.procedures; exe_env; source_file} =
+  let analyze_file_dependency proc_name =
+    let summary = Ondemand.analyze_proc_name_no_caller proc_name in
+    Option.bind summary ~f:(fun {Summary.payloads; proc_desc; _} ->
+        Field.get payload_field payloads |> Option.map ~f:(fun payload -> (proc_desc, payload)) )
+  in
+  checker
+    {InterproceduralAnalysis.procedures; source_file; file_exe_env= exe_env; analyze_file_dependency}

infer/src/backend/CallbackOfChecker.mli

@@ -0,0 +1,26 @@
+(*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *)
+
+open! IStd
+
+(** Conversions from checkers taking "functional" {!Interprocedural.t} et al. payloads to
+    {!Callbacks.proc_callback_t} and friends. *)
+
+val interprocedural :
+     (Payloads.t, 'payload option) Field.t
+  -> ('payload InterproceduralAnalysis.t -> 'payload option)
+  -> Callbacks.proc_callback_t
+(** [interprocedural field checker] expects [checker] to compute a payload (option) suitable for
+    [field], given an inter-procedural analysis of callees that computes the same payload type *)
+
+val interprocedural_file :
+     (Payloads.t, 'payload option) Field.t
+  -> ('payload InterproceduralAnalysis.file_t -> IssueLog.t)
+  -> Callbacks.file_callback_t
+(** [interprocedural_file field checker] expects [checker] to compute an {!IssueLog.t} from the
+    file-level analysis, given an inter-procedural analysis of dependencies that computes the
+    payload type corresponding to [field] *)

infer/src/backend/registerCheckers.ml

@@ -18,63 +18,17 @@ let () =
     ()
 
 
-let () =
-  AnalysisCallbacks.set_callbacks
-    { get_proc_desc_f= Ondemand.get_proc_desc
-    ; html_debug_new_node_session_f= NodePrinter.with_session
-    ; proc_resolve_attributes_f= Summary.OnDisk.proc_resolve_attributes }
-
-
 type callback_fun =
   | Procedure of Callbacks.proc_callback_t
   | DynamicDispatch of Callbacks.proc_callback_t
   | File of {callback: Callbacks.file_callback_t; issue_dir: ResultsDirEntryName.id}
 
-let proc_callback_of_interprocedural payload_field checker {Callbacks.summary; exe_env} =
-  let analyze_dependency proc_name =
-    let summary = Ondemand.analyze_proc_name ~caller_summary:summary proc_name in
-    Option.bind summary ~f:(fun {Summary.payloads; proc_desc; _} ->
-        Field.get payload_field payloads |> Option.map ~f:(fun payload -> (proc_desc, payload)) )
-  in
-  let analyze_pdesc_dependency proc_desc =
-    let summary = Ondemand.analyze_proc_desc ~caller_summary:summary proc_desc in
-    Option.bind summary ~f:(fun {Summary.payloads; _} ->
-        Field.get payload_field payloads |> Option.map ~f:(fun payload -> payload) )
-  in
-  let stats = ref summary.Summary.stats in
-  let update_stats ?add_symops ?failure_kind () =
-    stats := Summary.Stats.update ?add_symops ?failure_kind !stats
-  in
-  let result =
-    checker
-      { InterproceduralAnalysis.proc_desc= Summary.get_proc_desc summary
-      ; tenv= Exe_env.get_tenv exe_env (Summary.get_proc_name summary)
-      ; err_log= Summary.get_err_log summary
-      ; exe_env
-      ; analyze_dependency
-      ; analyze_pdesc_dependency
-      ; update_stats }
-  in
-  {summary with payloads= Field.fset payload_field summary.payloads result; stats= !stats}
-
-
 let dynamic_dispatch payload_field checker =
-  DynamicDispatch (proc_callback_of_interprocedural payload_field checker)
-
-
-let file_callback_of_interprocedural_file payload_field checker
-    {Callbacks.procedures; exe_env; source_file} =
-  let analyze_file_dependency proc_name =
-    let summary = Ondemand.analyze_proc_name_no_caller proc_name in
-    Option.bind summary ~f:(fun {Summary.payloads; proc_desc; _} ->
-        Field.get payload_field payloads |> Option.map ~f:(fun payload -> (proc_desc, payload)) )
-  in
-  checker
-    {InterproceduralAnalysis.procedures; source_file; file_exe_env= exe_env; analyze_file_dependency}
+  DynamicDispatch (CallbackOfChecker.interprocedural payload_field checker)
 
 
 let file issue_dir payload_field checker =
-  File {callback= file_callback_of_interprocedural_file payload_field checker; issue_dir}
+  File {callback= CallbackOfChecker.interprocedural_file payload_field checker; issue_dir}
 
 
 let proc_callback_of_intraprocedural ?payload_field checker {Callbacks.summary; exe_env} =