Don't warn about direct ivar access for atomic readonly properties

Reviewed By: jvillard

Differential Revision: D26425553

fbshipit-source-id: f1aeb3a07

infer/documentation/checkers/ASTLanguage.md

@@ -217,6 +217,7 @@ is_class ("class_name")
 is_const_var ()
 is_global_var ()
 is_ivar_atomic ()
+is_ivar_readonly ()
 is_method_property_accessor_of_ivar ()
 is_node ("node_name")
 is_objc_constructor ()

infer/lib/linter_rules/linters.al

@@ -9,7 +9,9 @@ DEFINE-CHECKER DIRECT_ATOMIC_PROPERTY_ACCESS = {
 
     SET report_when =
       WHEN
-            ((NOT context_in_synchronized_block()) AND is_ivar_atomic())
+            is_ivar_atomic()
+            AND NOT context_in_synchronized_block()
+            AND NOT is_ivar_readonly()
             AND NOT is_method_property_accessor_of_ivar()
             AND NOT is_objc_constructor()
             AND NOT is_objc_dealloc()

infer/src/al/CTL.ml

@@ -634,6 +634,8 @@ let eval_Atomic pred_name_ args an lcxt =
       CPredicates.is_in_objc_category_named lcxt name
   | "is_in_objc_protocol_named", [name], _ ->
       CPredicates.is_in_objc_protocol_named lcxt name
+  | "is_ivar_readonly", [], an ->
+      CPredicates.is_ivar_readonly an
   | "is_ivar_atomic", [], an ->
       CPredicates.is_ivar_atomic an
   | "is_method_property_accessor_of_ivar", [], an ->

infer/src/al/cPredicates.ml

@@ -713,6 +713,22 @@ let is_ivar_atomic an =
       false
 
 
+(* checks if ivar is defined among a set of fields and if it is readonly *)
+let is_ivar_readonly an =
+  match an with
+  | Ctl_parser_types.Stmt (Clang_ast_t.ObjCIvarRefExpr (_, _, _, irei)) -> (
+      let dr_ref = irei.Clang_ast_t.ovrei_decl_ref in
+      let ivar_pointer = dr_ref.Clang_ast_t.dr_decl_pointer in
+      match CAst_utils.get_decl ivar_pointer with
+      | Some d ->
+          let attributes = get_ivar_attributes d in
+          List.exists ~f:(PolyVariantEqual.( = ) `Readonly) attributes
+      | _ ->
+          false )
+  | _ ->
+      false
+
+
 let is_method_property_accessor_of_ivar an context =
   let open Clang_ast_t in
   match an with

infer/src/al/cPredicates.mli

@@ -98,7 +98,10 @@ val context_in_synchronized_block : CLintersContext.context -> bool
 (** true if the current node is in the context of a synchronized objc block *)
 
 val is_ivar_atomic : Ctl_parser_types.ast_node -> bool
-(** [is_ivar_atomic an] is true iff an denotes an atomi objc ivar *)
+(** [is_ivar_atomic an] is true iff an denotes an atomic objc ivar *)
+
+val is_ivar_readonly : Ctl_parser_types.ast_node -> bool
+(** [is_ivar_readonly an] is true iff an denotes a readonly objc ivar *)
 
 val is_method_property_accessor_of_ivar :
   Ctl_parser_types.ast_node -> CLintersContext.context -> bool

infer/tests/codetoanalyze/objc/linters/atomic_prop.m

@@ -25,7 +25,7 @@
 @property(nonatomic) int* p;
 @property int* q; // atomic by default
 @property(atomic, assign) float f;
-
+@property(atomic, readonly, assign) float fReadonly;
 @property(strong) B* b;
 
 - (void)write_p:(int)i;
@@ -115,4 +115,8 @@
   b();
 }
 
+- (float)readonlyAccess {
+  return _fReadonly; // good access
+}
+
 @end

website/docs/checker-linters.md

@@ -232,6 +232,7 @@ is_class ("class_name")
 is_const_var ()
 is_global_var ()
 is_ivar_atomic ()
+is_ivar_readonly ()
 is_method_property_accessor_of_ivar ()
 is_node ("node_name")
 is_objc_constructor ()