[ThreadSafety] Releasing lock at the end of the procedure if it has a lock_guard field.

Reviewed By: sblackshear

Differential Revision: D5255450

fbshipit-source-id: ff43c2a

infer/src/checkers/ThreadSafety.ml

@@ -910,7 +910,18 @@ let analyze_procedure { Callbacks.proc_desc; tenv; summary; } =
           let return_attributes =
             try AttributeMapDomain.find return_var_ap attribute_map
             with Not_found -> AttributeSetDomain.empty in
-          let post = thumbs_up, threads, locks, accesses, return_attributes in
+          (* A hack for modeling lock_guard by releasing a
+             lock at the end of the procedure, as destructors are not modeled yet *)
+          let update_locks = match Procdesc.get_proc_name proc_desc with
+            | ObjC_Cpp _ when locks ->
+                let matcher = QualifiedCppName.Match.of_fuzzy_qual_names ["std::lock_guard"] in
+                (* Unlock, if the procedure contains a local field of type std::lock_guard *)
+                not (List.exists (Procdesc.get_locals proc_desc) ~f:(fun (_, ft) ->
+                    Option.exists (Typ.name ft) ~f:(fun name ->
+                        QualifiedCppName.Match.match_qualifiers matcher (Typ.Name.qual_name name))
+                  ))
+            | _ -> locks in
+          let post = thumbs_up, threads, update_locks, accesses, return_attributes in
           Summary.update_summary post summary
       | None ->
           summary

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

@@ -6,5 +6,6 @@ codetoanalyze/cpp/threadsafety/basics_with_mutex.cpp, basics::BasicsWithHeader_g
 codetoanalyze/cpp/threadsafety/lock_guard.cpp, basics::LockGuard_get2, 3, THREAD_SAFETY_VIOLATION, [<Beginning of read trace>,access to `suspiciously_written`,<Beginning of write trace>,access to `suspiciously_written`]
 codetoanalyze/cpp/threadsafety/lock_guard.cpp, basics::LockGuard_get3, 0, THREAD_SAFETY_VIOLATION, [<Beginning of read trace>,access to `not_guarded`,<Beginning of write trace>,access to `not_guarded`]
 codetoanalyze/cpp/threadsafety/lock_guard.cpp, basics::LockGuard_get4, 0, THREAD_SAFETY_VIOLATION, [<Beginning of read trace>,access to `suspiciously_read`,<Beginning of write trace>,access to `suspiciously_read`]
+codetoanalyze/cpp/threadsafety/lock_guard.cpp, basics::LockGuard_test1, 2, THREAD_SAFETY_VIOLATION, [<Beginning of read trace>,access to `suspiciously_read`,<Beginning of write trace>,access to `suspiciously_read`]
 codetoanalyze/cpp/threadsafety/lock_guard_with_scope.cpp, basics::LockGuardWithScope_get3, 0, THREAD_SAFETY_VIOLATION, [<Beginning of read trace>,access to `not_guarded`,<Beginning of write trace>,access to `not_guarded`]
 codetoanalyze/cpp/threadsafety/lock_guard_with_scope.cpp, basics::LockGuardWithScope_get4, 0, THREAD_SAFETY_VIOLATION, [<Beginning of read trace>,access to `suspiciously_read`,<Beginning of write trace>,access to `suspiciously_read`]

infer/tests/codetoanalyze/cpp/threadsafety/lock_guard.cpp

@@ -41,6 +41,11 @@ class LockGuard {
 
   int get4() { return suspiciously_read; }
 
+  int test1() {
+    int result = get1();
+    return suspiciously_read + result;
+  }
+
  private:
   int well_guarded;
   int suspiciously_read;