[impurity] clarify string parameter of `ImpurityDomain.add_to_errlog`

Summary:
Instead of a string argument named `~str` pass `Formal | Global` and let
`add_to_errlog` figure out how to print it.

Reviewed By: ezgicicek

Differential Revision: D17907657

fbshipit-source-id: ed09aab72

infer/src/checkers/impurity.ml

@@ -125,13 +125,14 @@ let report_errors summary modified_opt =
         impure_fun_desc
   | Some (ImpurityDomain.{modified_globals; modified_params} as astate) ->
       if Purity.should_report pdesc && not (ImpurityDomain.is_pure astate) then
-        let modified_ltr ~str set acc =
-          ImpurityDomain.ModifiedVarSet.fold (ImpurityDomain.add_to_errlog ~nesting:1 ~str) set acc
+        let modified_ltr param_source set acc =
+          ImpurityDomain.ModifiedVarSet.fold
+            (ImpurityDomain.add_to_errlog ~nesting:1 param_source)
+            set acc
         in
         let ltr =
           impure_fun_ltr
-          :: modified_ltr ~str:"parameter" modified_params
-               (modified_ltr ~str:"global var" modified_globals [])
+          :: modified_ltr Formal modified_params (modified_ltr Global modified_globals [])
         in
         Reporting.log_error summary ~loc:pname_loc ~ltr IssueType.impure_function impure_fun_desc
   ) ;

infer/src/checkers/impurityDomain.ml

@@ -43,13 +43,23 @@ let join astate1 astate2 =
       astate1 astate2
 
 
-let add_to_errlog ~nesting ~str ModifiedVar.{var; trace_list} errlog =
+type param_source = Formal | Global
+
+let pp_param_source fmt = function
+  | Formal ->
+      F.pp_print_string fmt "parameter"
+  | Global ->
+      F.pp_print_string fmt "global variable"
+
+
+let add_to_errlog ~nesting param_source ModifiedVar.{var; trace_list} errlog =
   let rec aux ~nesting rev_errlog action =
     match action with
     | WrittenTo (PulseDomain.InterprocAction.Immediate {location}) ->
         let rev_errlog =
           Errlog.make_trace_element nesting location
-            (F.asprintf "%s '%a' is modified at %a" str Var.pp var Location.pp location)
+            (F.asprintf "%a '%a' is modified at %a" pp_param_source param_source Var.pp var
+               Location.pp location)
             []
           :: rev_errlog
         in
@@ -57,14 +67,14 @@ let add_to_errlog ~nesting ~str ModifiedVar.{var; trace_list} errlog =
     | WrittenTo (PulseDomain.InterprocAction.ViaCall {action; f; location}) ->
         aux ~nesting:(nesting + 1)
           ( Errlog.make_trace_element nesting location
-              (F.asprintf "%s '%a' is modified when calling %a at %a" str Var.pp var
-                 PulseDomain.CallEvent.describe f Location.pp location)
+              (F.asprintf "%a '%a' is modified when calling %a at %a" pp_param_source param_source
+                 Var.pp var PulseDomain.CallEvent.describe f Location.pp location)
               []
           :: rev_errlog )
           (WrittenTo action)
     | Invalid trace ->
         PulseDomain.Trace.add_to_errlog
-          ~header:(F.asprintf "%s '%a'" str Var.pp var)
+          ~header:(F.asprintf "%a '%a'" pp_param_source param_source Var.pp var)
           (fun f invalidation ->
             F.fprintf f "%a here" PulseDomain.Invalidation.describe invalidation )
           trace rev_errlog

infer/src/checkers/impurityDomain.mli

@@ -27,9 +27,11 @@ val pure : t
 
 val is_pure : t -> bool
 
+type param_source = Formal | Global
+
 val add_to_errlog :
      nesting:int
-  -> str:string
+  -> param_source
   -> ModifiedVar.t
   -> Errlog.loc_trace_elem list
   -> Errlog.loc_trace_elem list

infer/tests/codetoanalyze/cpp/impurity/issues.exp

@@ -6,15 +6,15 @@ codetoanalyze/cpp/impurity/array_test.cpp, array_mod_impure, 0, IMPURE_FUNCTION,
 codetoanalyze/cpp/impurity/array_test.cpp, call_array_mod_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function call_array_mod_impure,parameter 'a' is modified when calling `array_mod_impure()` at line 22, column 3,parameter 'a' is modified at line 9, column 3]
 codetoanalyze/cpp/impurity/array_test.cpp, modify_direct_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function modify_direct_impure,parameter 'array' is modified at line 40, column 60]
 codetoanalyze/cpp/impurity/array_test.cpp, modify_ptr_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function modify_ptr_impure,parameter 'array' is modified at line 44, column 3]
-codetoanalyze/cpp/impurity/global_test.cpp, call_modify_global, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function call_modify_global,global var 'a' is modified when calling `modify_global_array_impure()` at line 16, column 3,global var 'a' is modified at line 12, column 37,global var 'x' is modified when calling `modify_global_primitive_impure()` at line 15, column 3,global var 'x' is modified at line 10, column 41]
-codetoanalyze/cpp/impurity/global_test.cpp, local_static_var_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function local_static_var_impure,global var 'local_static_var_impure.arr' is modified at line 26, column 3,global var 'local_static_var_impure.arr' is modified at line 27, column 3]
-codetoanalyze/cpp/impurity/global_test.cpp, modify_global_array_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function modify_global_array_impure,global var 'a' is modified at line 12, column 37]
-codetoanalyze/cpp/impurity/global_test.cpp, modify_global_inside_lamda_impure::lambda_global_test.cpp:33:14::operator(), 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function modify_global_inside_lamda_impure::lambda_global_test.cpp:33:14::operator(),global var 'x' is modified at line 33, column 22]
-codetoanalyze/cpp/impurity/global_test.cpp, modify_global_primitive_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function modify_global_primitive_impure,global var 'x' is modified at line 10, column 41]
+codetoanalyze/cpp/impurity/global_test.cpp, call_modify_global, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function call_modify_global,global variable 'a' is modified when calling `modify_global_array_impure()` at line 16, column 3,global variable 'a' is modified at line 12, column 37,global variable 'x' is modified when calling `modify_global_primitive_impure()` at line 15, column 3,global variable 'x' is modified at line 10, column 41]
+codetoanalyze/cpp/impurity/global_test.cpp, local_static_var_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function local_static_var_impure,global variable 'local_static_var_impure.arr' is modified at line 26, column 3,global variable 'local_static_var_impure.arr' is modified at line 27, column 3]
+codetoanalyze/cpp/impurity/global_test.cpp, modify_global_array_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function modify_global_array_impure,global variable 'a' is modified at line 12, column 37]
+codetoanalyze/cpp/impurity/global_test.cpp, modify_global_inside_lamda_impure::lambda_global_test.cpp:33:14::operator(), 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function modify_global_inside_lamda_impure::lambda_global_test.cpp:33:14::operator(),global variable 'x' is modified at line 33, column 22]
+codetoanalyze/cpp/impurity/global_test.cpp, modify_global_primitive_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function modify_global_primitive_impure,global variable 'x' is modified at line 10, column 41]
 codetoanalyze/cpp/impurity/invalid_test.cpp, delete_param_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function delete_param_impure,parameter 's',was invalidated by `delete` here]
 codetoanalyze/cpp/impurity/invalid_test.cpp, double_free_global_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function double_free_global_impure]
 codetoanalyze/cpp/impurity/invalid_test.cpp, double_free_global_impure, 2, USE_AFTER_FREE, no_bucket, ERROR, [invalidation part of the trace starts here,when calling `free_global_pointer_impure` here,memory was invalidated by call to `free()` here,use-after-lifetime part of the trace starts here,when calling `free_global_pointer_impure` here,invalid access occurs here]
-codetoanalyze/cpp/impurity/invalid_test.cpp, free_global_pointer_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function free_global_pointer_impure,global var 'global_pointer',was invalidated by call to `free()` here]
+codetoanalyze/cpp/impurity/invalid_test.cpp, free_global_pointer_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function free_global_pointer_impure,global variable 'global_pointer',was invalidated by call to `free()` here]
 codetoanalyze/cpp/impurity/invalid_test.cpp, free_param_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function free_param_impure,parameter 'x',was invalidated by call to `free()` here]
 codetoanalyze/cpp/impurity/invalid_test.cpp, reassign_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function reassign_impure,parameter 's' is modified at line 34, column 3]
 codetoanalyze/cpp/impurity/param_test.cpp, create_cycle_impure, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function create_cycle_impure,parameter 'x' is modified at line 23, column 44]