Translate ImplicitValueInitExpr

Summary:public This also required a refactoring of InitListExpr.
The idea is that ImplicitValueInitExpr can stand for initialising a whole struct,
so we translating as a list of zero expressions, according to the struct's fields,
which is then paired with a list of field expressions, such that one get a list of
assignment instructions.

Reviewed By: ddino

Differential Revision: D2999875

fb-gh-sync-id: 7f609a0
shipit-source-id: 7f609a0

infer/src/backend/sil.ml

@@ -873,6 +873,13 @@ let typ_strip_ptr = function
   | Tptr (t, _) -> t
   | _ -> assert false
 
+let zero_value_of_numerical_type typ =
+  match typ with
+  | Tint _ -> Const (Cint Int.zero)
+  | Tfloat _ -> Const (Cfloat 0.0)
+  | Tptr _ -> Const (Cint Int.null)
+  | _ -> assert false
+
 let pvar_get_name pv = pv.pv_name
 
 let pvar_to_string pv = Mangled.to_string pv.pv_name

infer/src/backend/sil.mli

@@ -581,6 +581,8 @@ val path_pos_equal : path_pos -> path_pos -> bool
 (** turn a *T into a T. fails if [typ] is not a pointer type *)
 val typ_strip_ptr : typ -> typ
 
+val zero_value_of_numerical_type : typ -> exp
+
 val pvar_get_name : pvar -> Mangled.t
 
 val pvar_to_string : pvar -> string

infer/src/clang/cTrans.ml

@@ -366,14 +366,20 @@ struct
     let typ = CTypes_decl.get_type_from_expr_info expr_info trans_state.context.CContext.tenv in
     (* constant will be different depending on type *)
     let zero_opt = match typ with
-      | Sil.Tfloat _ -> Some (Sil.Cfloat 0.0)
-      | Sil.Tptr _ -> Some (Sil.Cint Sil.Int.null)
+      | Sil.Tfloat _  | Sil.Tptr _ | Sil.Tint _ -> Some (Sil.zero_value_of_numerical_type typ)
       | Sil.Tvoid -> None
-      | _ -> Some (Sil.Cint Sil.Int.zero) in
+      | _ -> Some (Sil.Const (Sil.Cint Sil.Int.zero)) in
     match zero_opt with
-    | Some zero -> { empty_res_trans with exps = [(Sil.Const zero, typ)] }
+    | Some zero -> { empty_res_trans with exps = [(zero, typ)] }
     | _ -> empty_res_trans
 
+  let implicitValueInitExpr_trans trans_state expr_info =
+    let (var_exp, _) = extract_var_exp_of_fail trans_state in
+    let tenv = trans_state.context.CContext.tenv in
+    let typ = CTypes_decl.get_type_from_expr_info expr_info trans_state.context.CContext.tenv in
+    let exps = var_or_zero_in_init_list tenv var_exp typ ~return_zero:true in
+    { empty_res_trans with exps = exps }
+
   let nullStmt_trans succ_nodes =
     { empty_res_trans with root_nodes = succ_nodes }
 
@@ -723,7 +729,6 @@ struct
              let creating_node =
                (PriorityNode.own_priority_node trans_state_pri.priority stmt_info) &&
                (IList.length instr_bin >0) in
-
              let extra_instrs, extra_ids, exp_to_parent =
                if (is_binary_assign_op binary_operator_info)
                (* assignment operator result is lvalue in CPP, rvalue in C, *)
@@ -1506,93 +1511,38 @@ struct
     instruction trans_state (Clang_ast_t.CompoundStmt (stmt_info, [assign_next_object; loop]))
 
   and initListExpr_trans trans_state stmt_info expr_info stmts =
-    let open General_utils in
-    let var_exp, _ = match trans_state.var_exp_typ with Some e -> e | _ -> assert false in
     let context = trans_state.context in
-    let succ_nodes = trans_state.succ_nodes in
-    let rec collect_right_hand_exprs ts stmt = match stmt with
-      | Clang_ast_t.InitListExpr (_ , stmts , _) ->
-          IList.flatten (IList.map (collect_right_hand_exprs ts) stmts)
-      | _ ->
-          let trans_state' = { ts with succ_nodes = []} in
-          let res_trans_stmt = instruction trans_state' stmt in
-          let (exp, typ) = extract_exp_from_list res_trans_stmt.exps
-              "WARNING: in InitListExpr we expect the translation of each stmt to return one expression.\n" in
-          let is_owning_method = CTrans_utils.is_owning_method stmt in
-          let is_method_call = CTrans_utils.is_method_call stmt in
-          [(res_trans_stmt.ids, res_trans_stmt.instrs, exp, is_method_call, is_owning_method, typ)] in
-    let rec collect_left_hand_exprs e typ tns =
-      match typ with
-      | Sil.Tvar tn ->
-          (match Sil.tenv_lookup context.CContext.tenv tn with
-           | Some struct_typ -> collect_left_hand_exprs e (Sil.Tstruct struct_typ) tns
-           | _ -> [[(e, typ)]] (*This case is an error, shouldn't happen.*))
-      | Sil.Tstruct { Sil.instance_fields } as type_struct ->
-          let lh_exprs = IList.map ( fun (fieldname, _, _) ->
-              Sil.Lfield (e, fieldname, type_struct) )
-              instance_fields in
-          let lh_types = IList.map ( fun (_, fieldtype, _) -> fieldtype)
-              instance_fields in
-          IList.map (fun (e, t) -> IList.flatten (collect_left_hand_exprs e t tns)) (zip lh_exprs lh_types)
-      | Sil.Tarray (arrtyp, Sil.Const (Sil.Cint n)) ->
-          let size = Sil.Int.to_int n in
-          let indices = list_range 0 (size - 1) in
-          let index_constants = IList.map
-              (fun i -> (Sil.Const (Sil.Cint (Sil.Int.of_int i))))
-              indices in
-          let lh_exprs = IList.map
-              (fun index_expr -> Sil.Lindex (e, index_expr))
-              index_constants in
-          let lh_types = replicate size arrtyp in
-          IList.map (fun (e, t) -> IList.flatten (collect_left_hand_exprs e t tns)) (zip lh_exprs lh_types)
-      | _ -> [ [(e, typ)] ] in
+    let tenv = context.tenv in
     let trans_state_pri = PriorityNode.try_claim_priority_node trans_state stmt_info in
+    let sil_loc = CLocation.get_sil_location stmt_info context in
+    let var_exp, _ = extract_var_exp_of_fail trans_state in
     let var_type =
       CTypes_decl.type_ptr_to_sil_type context.CContext.tenv expr_info.Clang_ast_t.ei_type_ptr in
-    let lh = IList.flatten (collect_left_hand_exprs var_exp var_type StringSet.empty) in
-    let rh = IList.flatten (IList.map (collect_right_hand_exprs trans_state_pri) stmts ) in
-    if IList.length rh != IList.length lh then (
+    let lh = var_or_zero_in_init_list tenv var_exp var_type ~return_zero:false in
+    let rec collect_right_hand_exprs stmt = match stmt with
+      | Clang_ast_t.InitListExpr (_ , stmts , _) ->
+          CTrans_utils.collect_res_trans (IList.map collect_right_hand_exprs stmts)
+      | _ -> instruction trans_state stmt in
+    let res_trans_subexpr_list = IList.map collect_right_hand_exprs stmts in
+    let rh_exps = collect_exprs res_trans_subexpr_list in
+    if IList.length rh_exps != IList.length lh then
       (* If the right hand expressions are not as many as the left hand expressions something's wrong *)
-      { empty_res_trans with root_nodes = succ_nodes }
-    ) else (
+      { empty_res_trans with root_nodes = trans_state.succ_nodes }
+    else
       (* Creating new instructions by assigning right hand side to left hand side expressions *)
-      let sil_loc = CLocation.get_sil_location stmt_info context in
-      let big_zip = IList.map
-          (fun ( (lh_exp, lh_t), (_, _, rh_exp, is_method_call, rhs_owning_method, rh_t) ) ->
-             let is_pointer_object = ObjcInterface_decl.is_pointer_to_objc_class context.CContext.tenv rh_t in
-             if !Config.arc_mode && (is_method_call || is_pointer_object) then
-               (* In arc mode, if it's a method call or we are initializing with a pointer to objc class *)
-               (* we need to add retain/release *)
-               let (e, instrs, ids) =
-                 CArithmetic_trans.assignment_arc_mode
-                   lh_exp lh_t rh_exp sil_loc rhs_owning_method true in
-               ([(e, lh_t)], instrs, ids)
-             else
-               ([], [Sil.Set (lh_exp, lh_t, rh_exp, sil_loc)], []))
-          (General_utils.zip lh rh) in
-      let rh_instrs = IList.flatten (IList.map (fun (_, instrs, _, _, _, _) -> instrs) rh) in
-      let assign_instrs = IList.flatten (IList.map (fun (_, instrs, _) -> instrs) big_zip) in
-      let assign_ids = IList.flatten (IList.map (fun (_, _, ids) -> ids) big_zip) in
-      let instructions = IList.append rh_instrs assign_instrs in
-      let rh_ids = IList.flatten (IList.map (fun (ids, _, _, _, _, _) -> ids) rh) in
-      let ids = IList.append rh_ids assign_ids in
-      if PriorityNode.own_priority_node trans_state_pri.priority stmt_info then (
-        let node_kind = Cfg.Node.Stmt_node "InitListExp" in
-        let node = create_node node_kind ids instructions sil_loc context in
-        Cfg.Node.set_succs_exn node succ_nodes [];
+      let assign_instr (lh_exp, lh_t) (rh_exp, _) = Sil.Set (lh_exp, lh_t, rh_exp, sil_loc) in
+      let assign_instrs = IList.map2 assign_instr lh rh_exps in
+      let initlist_expr_res =
         { empty_res_trans with
-          root_nodes = [node];
           exps = [(var_exp, var_type)];
           initd_exps = [var_exp];
-          ids = rh_ids;
-          instrs = instructions; }
-      ) else
-        { empty_res_trans with
-          exps = [(var_exp, var_type)];
-          initd_exps = [var_exp];
-          ids = rh_ids;
-          instrs = instructions; }
-    )
+          instrs = assign_instrs;
+        } in
+      let all_res_trans = res_trans_subexpr_list @ [initlist_expr_res] in
+      let nname = "InitListExp" in
+      let res_trans_to_parent = PriorityNode.compute_results_to_parent trans_state_pri sil_loc
+          nname stmt_info all_res_trans in
+      { res_trans_to_parent with exps = initlist_expr_res.exps }
 
   and init_expr_trans trans_state var_exp_typ var_stmt_info init_expr_opt =
     let open Clang_ast_t in
@@ -2301,6 +2251,9 @@ struct
     | CXXDefaultInitExpr (_, _, _, default_expr_info) ->
         cxxDefaultExpr_trans trans_state default_expr_info
 
+    | ImplicitValueInitExpr (_, _, expr_info) ->
+        implicitValueInitExpr_trans trans_state expr_info
+
     | s -> (Printing.log_stats
               "\n!!!!WARNING: found statement %s. \nACTION REQUIRED: Translation need to be defined. Statement ignored.... \n"
               (Ast_utils.string_of_stmt s);

infer/src/clang/cTrans_utils.ml

@@ -184,6 +184,11 @@ let collect_res_trans l =
             is_cpp_call_virtual = false; } in
   collect l empty_res_trans
 
+let extract_var_exp_of_fail transt_state =
+  match transt_state.var_exp_typ with
+  | Some var_exp_typ -> var_exp_typ
+  | None -> assert false
+
 (* priority_node is used to enforce some kind of policy for creating nodes *)
 (* in the cfg. Certain elements of the AST _must_ create nodes therefore   *)
 (* there is no need for them to use priority_node. Certain elements        *)
@@ -640,6 +645,42 @@ let is_dispatch_function stmt_list =
 let is_block_enumerate_function mei =
   mei.Clang_ast_t.omei_selector = CFrontend_config.enumerateObjectsUsingBlock
 
+(* This takes a variable of type struct or array and returns a list of expressions *)
+(* for each of its fields (also recursively, such that each field access is of a basic type) *)
+(* If the flag return_zero is true, the list will be a list of zero values, otherwise it will *)
+(* be a list of LField expressions *)
+let var_or_zero_in_init_list tenv e typ ~return_zero:return_zero =
+  let rec var_or_zero_in_init_list' e typ tns =
+    let open General_utils in
+    match typ with
+    | Sil.Tvar tn ->
+        (match Sil.tenv_lookup tenv tn with
+         | Some struct_typ -> var_or_zero_in_init_list' e (Sil.Tstruct struct_typ) tns
+         | _ -> [[(e, typ)]] (*This case is an error, shouldn't happen.*))
+    | Sil.Tstruct { Sil.instance_fields } as type_struct ->
+        let lh_exprs = IList.map ( fun (fieldname, _, _) ->
+            Sil.Lfield (e, fieldname, type_struct) ) instance_fields in
+        let lh_types = IList.map ( fun (_, fieldtype, _) -> fieldtype) instance_fields in
+        let exp_types = zip lh_exprs lh_types in
+        IList.map (fun (e, t) ->
+            IList.flatten (var_or_zero_in_init_list' e t tns)) exp_types
+    | Sil.Tarray (arrtyp, Sil.Const (Sil.Cint n)) ->
+        let size = Sil.Int.to_int n in
+        let indices = list_range 0 (size - 1) in
+        let index_constants =
+          IList.map (fun i -> (Sil.Const (Sil.Cint (Sil.Int.of_int i)))) indices in
+        let lh_exprs =
+          IList.map (fun index_expr -> Sil.Lindex (e, index_expr)) index_constants in
+        let lh_types = replicate size arrtyp in
+        let exp_types = zip lh_exprs lh_types in
+        IList.map (fun (e, t) ->
+            IList.flatten (var_or_zero_in_init_list' e t tns)) exp_types
+    | Sil.Tint _ | Sil.Tfloat _  | Sil.Tptr _ ->
+        let exp = if return_zero then Sil.zero_value_of_numerical_type typ else e in
+        [ [(exp, typ)] ]
+    | Sil.Tfun _ | Sil.Tvoid | Sil.Tarray _ -> assert false in
+  IList.flatten (var_or_zero_in_init_list' e typ StringSet.empty)
+
 (*
 (** Similar to extract_item_from_singleton but for option type *)
 let extract_item_from_option op warning_string =

infer/src/clang/cTrans_utils.mli

@@ -39,6 +39,10 @@ type trans_result = {
 
 val empty_res_trans: trans_result
 
+val collect_res_trans : trans_result list -> trans_result
+
+val extract_var_exp_of_fail : trans_state -> Sil.exp * Sil.typ
+
 val is_return_temp: continuation option -> bool
 
 val ids_to_parent: continuation option -> Ident.t list -> Ident.t list
@@ -215,3 +219,6 @@ val is_logical_negation_of_int : Sil.tenv -> Clang_ast_t.expr_info -> Clang_ast_
 val is_dispatch_function : Clang_ast_t.stmt list -> int option
 
 val is_block_enumerate_function : Clang_ast_t.obj_c_message_expr_info -> bool
+
+val var_or_zero_in_init_list : Sil.tenv -> Sil.exp -> Sil.typ -> return_zero:bool ->
+  (Sil.exp * Sil.typ) list

infer/tests/codetoanalyze/c/frontend/initialization/struct_initlistexpr.c

@@ -35,3 +35,26 @@ int field_set_correctly() {
   struct Employee e = {12, 3000.50, 12, 12, 2010};
   return 1 / (e.ssn - 12);
 }
+
+struct dotdot {
+  int a;
+  int b;
+};
+
+struct dot {
+  struct dotdot x;
+  int y;
+};
+struct rect {
+  struct dot origin;
+  int z;
+  int size;
+};
+
+typedef struct rect rect;
+
+int implicit_expr_set_correctly() {
+  rect imageDrawRect;
+  imageDrawRect = (rect){.size = 5};
+  return 1 / imageDrawRect.origin.x.a;
+}

infer/tests/codetoanalyze/c/frontend/initialization/struct_initlistexpr.c.dot

@@ -1,4 +1,19 @@
 digraph iCFG {
+18 [label="18:  BinaryOperatorStmt: Assign \n   *&imageDrawRect.origin.x.a:int =0 [line 58]\n  *&imageDrawRect.origin.x.b:int =0 [line 58]\n  *&imageDrawRect.origin.y:int =0 [line 58]\n  *&imageDrawRect.z:int =0 [line 58]\n  *&imageDrawRect.size:int =5 [line 58]\n  n$1=*&imageDrawRect:struct rect  [line 58]\n  REMOVE_TEMPS(n$1); [line 58]\n " shape="box"]
+	
+
+	 18 -> 17 ;
+17 [label="17:  Return Stmt \n   n$0=*&imageDrawRect.origin.x.a:int  [line 59]\n  *&return:int =(1 / n$0) [line 59]\n  REMOVE_TEMPS(n$0); [line 59]\n  NULLIFY(&imageDrawRect,false); [line 59]\n  APPLY_ABSTRACTION; [line 59]\n " shape="box"]
+	
+
+	 17 -> 16 ;
+16 [label="16: Exit implicit_expr_set_correctly \n  " color=yellow style=filled]
+	
+
+15 [label="15: Start implicit_expr_set_correctly\nFormals: \nLocals:  imageDrawRect:struct rect  \n   DECLARE_LOCALS(&return,&imageDrawRect); [line 56]\n " color=yellow style=filled]
+	
+
+	 15 -> 18 ;
 14 [label="14:  DeclStmt \n   *&e.ssn:int =12 [line 35]\n  *&e.salary:float =3000.500000 [line 35]\n  *&e.doj.date:int =12 [line 35]\n  *&e.doj.month:int =12 [line 35]\n  *&e.doj.year:int =2010 [line 35]\n " shape="box"]
 	
 

infer/tests/codetoanalyze/objc/frontend/vardecl/initlist.dot

@@ -7,7 +7,7 @@ digraph iCFG {
 	
 
 	 7 -> 6 ;
-6 [label="6:  DeclStmt \n   n$0=*&c1:class C * [line 24]\n  n$1=_fun_NSObject_init(n$0:class C *) virtual [line 24]\n  n$2=*&c1:class C * [line 24]\n  n$3=*&c2:class C * [line 24]\n  *&a[0]:class C *=n$1 [line 24]\n  _fun___objc_retain(n$2:class C *) [line 24]\n  *&a[1]:class C *=n$2 [line 24]\n  _fun___objc_retain(n$3:class C *) [line 24]\n  *&a[2]:class C *=n$3 [line 24]\n  REMOVE_TEMPS(n$0,n$1,n$2,n$3); [line 24]\n  NULLIFY(&c1,false); [line 24]\n  NULLIFY(&c2,false); [line 24]\n  APPLY_ABSTRACTION; [line 24]\n " shape="box"]
+6 [label="6:  DeclStmt \n   n$0=*&c1:class C * [line 24]\n  n$1=_fun_NSObject_init(n$0:class C *) virtual [line 24]\n  n$2=*&c1:class C * [line 24]\n  n$3=*&c2:class C * [line 24]\n  *&a[0]:class C *=n$1 [line 24]\n  *&a[1]:class C *=n$2 [line 24]\n  *&a[2]:class C *=n$3 [line 24]\n  REMOVE_TEMPS(n$0,n$1,n$2,n$3); [line 24]\n  NULLIFY(&c1,false); [line 24]\n  NULLIFY(&c2,false); [line 24]\n  APPLY_ABSTRACTION; [line 24]\n " shape="box"]
 	
 
 	 6 -> 5 ;

infer/tests/endtoend/objc/InitListExprTest.java

@@ -49,7 +49,7 @@ public class InitListExprTest {
   public void nullDereferenceTest() throws InterruptedException, IOException, InferException {
     InferResults inferResults = InferRunner.runInferC(inferCmd);
     String[] procedures = {
-        "point_coords_set_correctly", "field_set_correctly",
+        "point_coords_set_correctly", "field_set_correctly", "implicit_expr_set_correctly"
     };
     assertThat(
         "Results should contain divide by zero",