Translate functions coming from std headers od demand

Summary:
Translate code coming from std::headers only when it's reachable from user code during translation.
This way, we reduce number of functions analyzer sees and decreases size of cfg/number of .attr files

Reviewed By: jvillard

Differential Revision: D3797550

fbshipit-source-id: 2a9eb4c

infer/src/clang/cFrontend_decl.ml

@@ -144,8 +144,7 @@ struct
     let info = Clang_ast_proj.get_decl_tuple dec in
     CLocation.update_curr_file info;
     let source_range = info.Clang_ast_t.di_source_range in
-    let translate_location = CLocation.should_translate_lib source_range decl_trans_context in
+    let translate_when_used = match dec with
-    let always_translate_decl = match dec with
       | Clang_ast_t.FunctionDecl (_, name_info, _, _)
       | Clang_ast_t.CXXMethodDecl (_, name_info, _, _, _) ->
           (* named_decl_info.ni_name has name without template parameters.*)
@@ -154,13 +153,15 @@ struct
           let name = Ast_utils.get_qualified_name name_info in
           AttributesTable.is_whitelisted_cpp_method name
       | _ -> false in
+    let translate_location =
+      CLocation.should_translate_lib source_range decl_trans_context ~translate_when_used in
     let never_translate_decl = match dec with
       | Clang_ast_t.FunctionDecl (_, name_info, _, _)
       | Clang_ast_t.CXXMethodDecl (_, name_info, _, _, _) ->
           let fun_name = name_info.Clang_ast_t.ni_name in
           Str.string_match (Str.regexp "__infer_skip__" ) fun_name 0
       | _ -> false in
-    (not never_translate_decl) && (translate_location || always_translate_decl)
+    (not never_translate_decl) && translate_location
 
   (* Translate one global declaration *)
   let rec translate_one_declaration tenv cg cfg decl_trans_context dec =

infer/src/clang/cLocation.ml

@@ -101,7 +101,7 @@ let should_do_frontend_check (loc_start, _) =
 (* the headers because the dot files in the frontend tests should contain nothing *)
 (* else than the source file to avoid conflicts between different versions of the *)
 (* libraries in the CI *)
-let should_translate (loc_start, loc_end) decl_trans_context =
+let should_translate (loc_start, loc_end) decl_trans_context ~translate_when_used =
   let map_path_of pred loc =
     match loc.Clang_ast_t.sl_file with
     | Some f -> pred f
@@ -116,7 +116,7 @@ let should_translate (loc_start, loc_end) decl_trans_context =
   in
   let file_in_project = map_path_of file_in_project loc_end
                         || map_path_of file_in_project loc_start in
-  let translate_on_demand = file_in_project || Config.models_mode in
+  let translate_on_demand = translate_when_used || file_in_project || Config.models_mode in
   let file_in_models = map_path_of DB.file_is_in_cpp_model loc_end
                        || map_path_of DB.file_is_in_cpp_model loc_start in
   equal_current_source !curr_file
@@ -126,9 +126,9 @@ let should_translate (loc_start, loc_end) decl_trans_context =
   || (Config.cxx_experimental && decl_trans_context = `Translation && translate_on_demand
       && not Config.testing_mode)
 
-let should_translate_lib source_range decl_trans_context =
+let should_translate_lib source_range decl_trans_context ~translate_when_used =
   not Config.no_translate_libs
-  || should_translate source_range decl_trans_context
+  || should_translate source_range decl_trans_context ~translate_when_used
 
 let is_file_blacklisted file =
   let paths = Config.skip_clang_analysis_in_path in

infer/src/clang/cLocation.mli

@@ -21,7 +21,8 @@ val clang_to_sil_location : Clang_ast_t.source_location -> Cfg.Procdesc.t option
 
 val get_sil_location : Clang_ast_t.stmt_info -> CContext.t -> Location.t
 
-val should_translate_lib : Clang_ast_t.source_range -> CModule_type.decl_trans_context -> bool
+val should_translate_lib : Clang_ast_t.source_range -> CModule_type.decl_trans_context ->
+  translate_when_used:bool -> bool
 
 val should_do_frontend_check : Clang_ast_t.source_range -> bool