[inferbo] Limit narrowing to 5 iterations

Reviewed By: skcho

Differential Revision: D11534711

fbshipit-source-id: 608d26aa9

infer/src/absint/AbstractInterpreter.ml

@@ -199,8 +199,10 @@ module AbstractInterpreterCommon (TransferFunctions : TransferFunctions.SIL) = s
         else astate_pre
       in
       if
-        ((not is_narrowing) && Domain.( <= ) ~lhs:new_pre ~rhs:old_state.State.pre)
+        if is_narrowing then
-        || (is_narrowing && Domain.( <= ) ~lhs:old_state.State.pre ~rhs:new_pre)
+          (old_state.State.visit_count :> int) > Config.max_narrows
+          || Domain.( <= ) ~lhs:old_state.State.pre ~rhs:new_pre
+        else Domain.( <= ) ~lhs:new_pre ~rhs:old_state.State.pre
       then (inv_map, ReachedFixPoint)
       else
         let visit_count' = VisitCount.succ ~pdesc old_state.State.visit_count in

infer/src/base/Config.ml

@@ -220,6 +220,8 @@ let manual_racerd = "RACERD CHECKER OPTIONS"
 
 let manual_siof = "SIOF CHECKER OPTIONS"
 
+let max_narrows = 5
+
 (** Maximum number of widens that can be performed before the analysis will intentionally crash.
     Used to guard against divergence in the case that someone has implemented a bad widening
     operator *)

infer/src/base/Config.mli

@@ -119,6 +119,8 @@ val lint_issues_dir_name : string
 
 val load_average : float option
 
+val max_narrows : int
+
 val max_widens : int
 
 val meet_level : int