Ignore type change in UncheckedDerivedToBase cast

Summary: public
Infer gets confused with this cast. It happens when objects try
to access superclass field/method, but we shouldn't change type in
this case (for the sake of backend)

Reviewed By: dulmarod

Differential Revision: D2663905

fb-gh-sync-id: bbf1cb2

infer/src/clang/cTrans.ml

@@ -1751,7 +1751,7 @@ struct
       leaf_nodes = res_trans_stmt.leaf_nodes;
       ids = res_trans_stmt.ids @ cast_ids;
       instrs = res_trans_stmt.instrs @ cast_inst;
-      exps = [(cast_exp, typ)] }
+      exps = [cast_exp] }
 
   (* function used in the computation for both Member_Expr and ObjCIVarRefExpr *)
   and do_memb_ivar_ref_exp trans_state expr_info stmt_info stmt_list decl_ref  =

infer/src/clang/cTrans_utils.ml

@@ -385,27 +385,33 @@ let dereference_value_from_result sil_loc trans_result ~strip_pointer =
 
 let cast_operation context cast_kind exps cast_typ sil_loc is_objc_bridged =
   let (exp, typ) = extract_exp_from_list exps "" in
+  let exp_typ = match cast_kind with
+    | `UncheckedDerivedToBase -> typ  (* This cast ignores change of type *)
+    | _ -> cast_typ (* by default use the return type of cast expr *) in 
   if is_objc_bridged then
     let id, instr, exp = create_cast_instrs context exp typ cast_typ sil_loc in
-    [id], [instr], exp
+    [id], [instr], (exp, exp_typ)
   else
     match cast_kind with
     | `NoOp
     | `BitCast
     | `IntegralCast
+    | `DerivedToBase
+    | `UncheckedDerivedToBase
     | `IntegralToBoolean -> (* This is treated as a nop by returning the same expressions exps*)
-        ([],[], exp)
+        ([], [], (exp, exp_typ))
     | `LValueToRValue ->
         (* Takes an LValue and allow it to use it as RValue. *)
         (* So we assign the LValue to a temp and we pass it to the parent.*)
-        dereference_var_sil (exp, typ) sil_loc
+        let ids, instrs, deref_exp = dereference_var_sil (exp, typ) sil_loc in
+        ids, instrs, (deref_exp, exp_typ)
     | `CPointerToObjCPointerCast ->
-        ([], [], Sil.Cast(typ, exp))
+        [], [], (Sil.Cast(typ, exp), exp_typ)
     | _ ->
         Printing.log_err
           "\nWARNING: Missing translation for Cast Kind %s. The construct has been ignored...\n"
           (Clang_ast_j.string_of_cast_kind cast_kind);
-        ([],[], exp)
+        ([],[], (exp, exp_typ))
 
 let trans_assertion_failure sil_loc context =
   let assert_fail_builtin = Sil.Const (Sil.Cfun SymExec.ModelBuiltins.__infer_fail) in

infer/src/clang/cTrans_utils.mli

@@ -81,7 +81,7 @@ val dereference_value_from_result : Location.t -> trans_result -> strip_pointer:
 
 val cast_operation :
   CContext.t -> Clang_ast_t.cast_kind -> (Sil.exp * Sil.typ) list -> Sil.typ -> Location.t ->
-  bool -> Ident.t list * Sil.instr list * Sil.exp
+  bool -> Ident.t list * Sil.instr list * (Sil.exp * Sil.typ)
 
 val trans_assertion_failure : Location.t -> CContext.t -> trans_result
 

infer/tests/codetoanalyze/cpp/frontend/types/inheritance.cpp.dot

@@ -19,7 +19,7 @@ digraph iCFG {
 	
 
 	 20 -> 19 ;
-19 [label="19:  Call _fun_Base_fun \n   n$6=*&s2:class Sub * [line 28]\n  n$7=_fun_Base_fun(n$6:class Base *) [line 28]\n  REMOVE_TEMPS(n$6,n$7); [line 28]\n " shape="box"]
+19 [label="19:  Call _fun_Base_fun \n   n$6=*&s2:class Sub * [line 28]\n  n$7=_fun_Base_fun(n$6:class Sub *) [line 28]\n  REMOVE_TEMPS(n$6,n$7); [line 28]\n " shape="box"]
 	
 
 	 19 -> 18 ;

infer/tests/codetoanalyze/cpp/frontend/types/inheritance_field.cpp

@@ -46,6 +46,17 @@ int div0_cast_ref(Sub s) {
   return 1 / b.b1;
 }
 
+int div0_b1_s(Sub *s) {
+  s->b1 = 1;
+  s->s = 1;
+  return 1 / (s->b1 - s->s);
+}
+
+int div0_s_b1(Sub *s) {
+  s->b1 = 1;
+  s->s = 1;
+  return 1 / (s->b1 - s->s);
+}
 
 int div1_b1(Sub s) {
   s.b1 = 1;
@@ -57,4 +68,3 @@ int div1_cast(Sub *s) {
   Base1 *b = s;
   return 1 / b->b1;
 }
-

infer/tests/codetoanalyze/cpp/frontend/types/inheritance_field.cpp.dot

@@ -1,38 +1,76 @@
 digraph iCFG {
-31 [label="31:  BinaryOperatorStmt: Assign \n   n$3=*&s:class Sub * [line 56]\n  *n$3.b1:int =1 [line 56]\n  REMOVE_TEMPS(n$3); [line 56]\n " shape="box"]
+41 [label="41:  BinaryOperatorStmt: Assign \n   n$3=*&s:class Sub * [line 67]\n  *n$3.b1:int =1 [line 67]\n  REMOVE_TEMPS(n$3); [line 67]\n " shape="box"]
+	
+
+	 41 -> 40 ;
+40 [label="40:  DeclStmt \n   n$2=*&s:class Sub * [line 68]\n  *&b:struct Base1 *=n$2 [line 68]\n  REMOVE_TEMPS(n$2); [line 68]\n  NULLIFY(&s,false); [line 68]\n " shape="box"]
+	
+
+	 40 -> 39 ;
+39 [label="39:  Return Stmt \n   n$0=*&b:struct Base1 * [line 69]\n  n$1=*n$0.b1:int  [line 69]\n  *&return:int =(1 / n$1) [line 69]\n  REMOVE_TEMPS(n$0,n$1); [line 69]\n  NULLIFY(&b,false); [line 69]\n  APPLY_ABSTRACTION; [line 69]\n " shape="box"]
+	
+
+	 39 -> 38 ;
+38 [label="38: Exit div1_cast \n  " color=yellow style=filled]
+	
+
+37 [label="37: Start div1_cast\nFormals:  s:class Sub *\nLocals:  b:struct Base1 * \n   DECLARE_LOCALS(&return,&b); [line 66]\n  NULLIFY(&b,false); [line 66]\n " color=yellow style=filled]
+	
+
+	 37 -> 41 ;
+36 [label="36:  BinaryOperatorStmt: Assign \n   *&s.b1:int =1 [line 62]\n " shape="box"]
+	
+
+	 36 -> 35 ;
+35 [label="35:  Return Stmt \n   n$0=*&s.b1:int  [line 63]\n  *&return:int =(1 / n$0) [line 63]\n  REMOVE_TEMPS(n$0); [line 63]\n  NULLIFY(&s,false); [line 63]\n  APPLY_ABSTRACTION; [line 63]\n " shape="box"]
+	
+
+	 35 -> 34 ;
+34 [label="34: Exit div1_b1 \n  " color=yellow style=filled]
+	
+
+33 [label="33: Start div1_b1\nFormals:  s:class Sub \nLocals:  \n   DECLARE_LOCALS(&return); [line 61]\n " color=yellow style=filled]
+	
+
+	 33 -> 36 ;
+32 [label="32:  BinaryOperatorStmt: Assign \n   n$5=*&s:class Sub * [line 56]\n  *n$5.b1:int =1 [line 56]\n  REMOVE_TEMPS(n$5); [line 56]\n " shape="box"]
+	
+
+	 32 -> 31 ;
+31 [label="31:  BinaryOperatorStmt: Assign \n   n$4=*&s:class Sub * [line 57]\n  *n$4.s:int =1 [line 57]\n  REMOVE_TEMPS(n$4); [line 57]\n " shape="box"]
 	
 
 	 31 -> 30 ;
-30 [label="30:  DeclStmt \n   n$2=*&s:class Sub * [line 57]\n  *&b:struct Base1 *=n$2 [line 57]\n  REMOVE_TEMPS(n$2); [line 57]\n  NULLIFY(&s,false); [line 57]\n " shape="box"]
+30 [label="30:  Return Stmt \n   n$0=*&s:class Sub * [line 58]\n  n$1=*n$0.b1:int  [line 58]\n  n$2=*&s:class Sub * [line 58]\n  n$3=*n$2.s:int  [line 58]\n  *&return:int =(1 / (n$1 - n$3)) [line 58]\n  REMOVE_TEMPS(n$0,n$1,n$2,n$3); [line 58]\n  NULLIFY(&s,false); [line 58]\n  APPLY_ABSTRACTION; [line 58]\n " shape="box"]
 	
 
 	 30 -> 29 ;
-29 [label="29:  Return Stmt \n   n$0=*&b:struct Base1 * [line 58]\n  n$1=*n$0.b1:int  [line 58]\n  *&return:int =(1 / n$1) [line 58]\n  REMOVE_TEMPS(n$0,n$1); [line 58]\n  NULLIFY(&b,false); [line 58]\n  APPLY_ABSTRACTION; [line 58]\n " shape="box"]
+29 [label="29: Exit div0_s_b1 \n  " color=yellow style=filled]
 	
 
-	 29 -> 28 ;
+28 [label="28: Start div0_s_b1\nFormals:  s:class Sub *\nLocals:  \n   DECLARE_LOCALS(&return); [line 55]\n " color=yellow style=filled]
-28 [label="28: Exit div1_cast \n  " color=yellow style=filled]
 	
 
-27 [label="27: Start div1_cast\nFormals:  s:class Sub *\nLocals:  b:struct Base1 * \n   DECLARE_LOCALS(&return,&b); [line 55]\n  NULLIFY(&b,false); [line 55]\n " color=yellow style=filled]
+	 28 -> 32 ;
+27 [label="27:  BinaryOperatorStmt: Assign \n   n$5=*&s:class Sub * [line 50]\n  *n$5.b1:int =1 [line 50]\n  REMOVE_TEMPS(n$5); [line 50]\n " shape="box"]
 	
 
-	 27 -> 31 ;
+	 27 -> 26 ;
-26 [label="26:  BinaryOperatorStmt: Assign \n   *&s.b1:int =1 [line 51]\n " shape="box"]
+26 [label="26:  BinaryOperatorStmt: Assign \n   n$4=*&s:class Sub * [line 51]\n  *n$4.s:int =1 [line 51]\n  REMOVE_TEMPS(n$4); [line 51]\n " shape="box"]
 	
 
 	 26 -> 25 ;
-25 [label="25:  Return Stmt \n   n$0=*&s.b1:int  [line 52]\n  *&return:int =(1 / n$0) [line 52]\n  REMOVE_TEMPS(n$0); [line 52]\n  NULLIFY(&s,false); [line 52]\n  APPLY_ABSTRACTION; [line 52]\n " shape="box"]
+25 [label="25:  Return Stmt \n   n$0=*&s:class Sub * [line 52]\n  n$1=*n$0.b1:int  [line 52]\n  n$2=*&s:class Sub * [line 52]\n  n$3=*n$2.s:int  [line 52]\n  *&return:int =(1 / (n$1 - n$3)) [line 52]\n  REMOVE_TEMPS(n$0,n$1,n$2,n$3); [line 52]\n  NULLIFY(&s,false); [line 52]\n  APPLY_ABSTRACTION; [line 52]\n " shape="box"]
 	
 
 	 25 -> 24 ;
-24 [label="24: Exit div1_b1 \n  " color=yellow style=filled]
+24 [label="24: Exit div0_b1_s \n  " color=yellow style=filled]
 	
 
-23 [label="23: Start div1_b1\nFormals:  s:class Sub \nLocals:  \n   DECLARE_LOCALS(&return); [line 50]\n " color=yellow style=filled]
+23 [label="23: Start div0_b1_s\nFormals:  s:class Sub *\nLocals:  \n   DECLARE_LOCALS(&return); [line 49]\n " color=yellow style=filled]
 	
 
-	 23 -> 26 ;
+	 23 -> 27 ;
 22 [label="22:  BinaryOperatorStmt: Assign \n   *&s.b1:int =0 [line 44]\n " shape="box"]
 	
 

infer/tests/codetoanalyze/cpp/frontend/types/operator_overload.cpp.dot

@@ -10,7 +10,7 @@ digraph iCFG {
 	
 
 	 25 -> 27 ;
-24 [label="24:  Return Stmt \n   n$0=*&y:class Y & [line 48]\n  n$1=_fun_X_operator[](n$0:class X &,0:int ) [line 48]\n  *&return:int =(1 / n$1) [line 48]\n  REMOVE_TEMPS(n$0,n$1); [line 48]\n  NULLIFY(&y,false); [line 48]\n  APPLY_ABSTRACTION; [line 48]\n " shape="box"]
+24 [label="24:  Return Stmt \n   n$0=*&y:class Y & [line 48]\n  n$1=_fun_X_operator[](n$0:class Y &,0:int ) [line 48]\n  *&return:int =(1 / n$1) [line 48]\n  REMOVE_TEMPS(n$0,n$1); [line 48]\n  NULLIFY(&y,false); [line 48]\n  APPLY_ABSTRACTION; [line 48]\n " shape="box"]
 	
 
 	 24 -> 23 ;

infer/tests/endtoend/cpp/InheritanceFieldTest.java

@@ -53,6 +53,8 @@ public class InheritanceFieldTest {
         "div0_s",
         "div0_cast",
         "div0_cast_ref",
+        "div0_b1_s",
+        "div0_s_b1",
     };
     assertThat(
         "Results should contain the expected divide by zero",