[frontend] Do not create exceptional successors for return nodes

Summary: Exceptional successors were not meant to be created for return nodes, but they were created if try block had a single return statement.

Reviewed By: jvillard

Differential Revision: D8913371

fbshipit-source-id: 6ac85b21d

infer/src/clang/cTrans.ml

@@ -1909,8 +1909,14 @@ module CTrans_funct (F : CModule_type.CFrontend) : CModule_type.CTranslation = s
             try_control.root_nodes
           else try_control.leaf_nodes
         in
+        (* do not add exceptional successors to return nodes *)
         List.iter
-          ~f:(fun try_end -> Procdesc.set_succs_exn_only try_end catch_start_nodes)
+          ~f:(fun try_end ->
+            match Procdesc.Node.get_kind try_end with
+            | Procdesc.Node.Stmt_node "Return Stmt" ->
+                ()
+            | _ ->
+                Procdesc.set_succs_exn_only try_end catch_start_nodes )
           try_ends ;
         try_trans_result
     | _ ->

infer/tests/codetoanalyze/cpp/liveness/dead_stores.cpp

@@ -388,7 +388,7 @@ class Exceptions {
     return 0;
   }
 
-  int FN_unreachable_catch_bad() {
+  int unreachable_catch_bad() {
     int i = 1;
     try {
     } catch (...) {

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

@@ -1,5 +1,6 @@
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::Exceptions_FP_read_in_catch_tricky_ok, 1, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::Exceptions_dead_in_catch_bad, 4, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
+codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::Exceptions_unreachable_catch_bad, 1, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::FP_assign_array_tricky_ok, 3, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::capture_by_value_bad, 3, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::dead_pointer_bad, 2, DEAD_STORE, no_bucket, ERROR, [Write of unused value]

infer/tests/codetoanalyze/cpp/ownership/returns.cpp

@@ -128,4 +128,17 @@ const char* return_nullptr2_ok() {
   return local;
 }
 
+struct A {
+  ~A();
+};
+
+int try_catch_return_ok() {
+  A a;
+  try {
+    return 1;
+  } catch (...) {
+    return 2;
+  }
+}
+
 } // namespace returns

infer/tests/codetoanalyze/cpp/shared/exceptions/Exceptions.cpp.dot

@@ -193,7 +193,6 @@ digraph cfg {
 	
 
 	 "main.fad58de7366495db4650cfefac2fcd61_3" -> "main.fad58de7366495db4650cfefac2fcd61_2" ;
-	 "main.fad58de7366495db4650cfefac2fcd61_3" -> "main.fad58de7366495db4650cfefac2fcd61_4" [color="red" ];
 "main.fad58de7366495db4650cfefac2fcd61_4" [label="4:  Return Stmt \n   *&return:int=-1 [line 76, column 5]\n " shape="box"]