[infer] add infrastructure for function attributes in sil and clang

Summary:
@public
This adds basic support for function attributes in Sil, and for translating
attributes from the clang frontend to these new Sil attributes. For now only
the sentinel attribute is translated.

Note that attributes normally have parameters, but they are currently missing
from the clang plugin.

Test Plan:
Add

  (match Sil.get_sentinel_func_attribute_value (Cfg.Procdesc.get_attributes callee_pdesc).Sil.func_attributes with
  | Some _ -> L.out "found sentinel attribute!\n"
  | _ -> ());

between lines 947 and 948 of symbExec.ml, then analyze a file containing:

  int add_all_ints(int a, ...) __attribute__ ((sentinel));
  int foo(void) { return add_all_ints(1, 2, 3, (void *)0); }

then `grep 'found sentinel' infer-out/log/analyzer_out`

-> the sentinel attribute is correctly passed from the frontend to the backend.

infer/src/backend/cfg.mli

@@ -322,4 +322,4 @@ val check_cfg_connectedness : cfg -> unit
 val get_block_pdesc : cfg -> Mangled.t -> Procdesc.t option
 
 (** Removes seeds variables from a prop corresponding to captured variables in an objc block *)
-val remove_seed_captured_vars_block : Mangled.t list -> Prop.normal Prop.t -> Prop.normal Prop.t
+val remove_seed_captured_vars_block : Mangled.t list -> Prop.normal Prop.t -> Prop.normal Prop.t

infer/src/backend/sil.ml

@@ -24,6 +24,9 @@ type item_annotation = (annotation * bool) list
 type method_annotation =
   item_annotation * item_annotation list
 
+type func_attribute =
+  | FA_sentinel of int * int (** __attribute__((sentinel(int, int))) *)
+
 (** Programming language. *)
 type language = C_CPP | Java
 
@@ -40,6 +43,7 @@ type proc_attributes =
     is_objc_instance_method : bool; (** the procedure is an objective-C instance method *)
     mutable is_synthetic_method : bool; (** the procedure is a synthetic method *)
     language : language;
+    func_attributes : func_attribute list;
     method_annotation : method_annotation;
   }
 
@@ -52,6 +56,7 @@ let copy_proc_attributes pa =
     is_objc_instance_method = pa.is_objc_instance_method;
     is_synthetic_method = pa.is_synthetic_method;
     language = pa.language;
+    func_attributes = pa.func_attributes;
     method_annotation = pa.method_annotation;
   }
 
@@ -100,6 +105,15 @@ let pp_item_annotation fmt item_annotation =
 let pp_method_annotation s fmt (ia, ial) =
   F.fprintf fmt "%a %s(%a)" pp_item_annotation ia s (pp_seq pp_item_annotation) ial
 
+(** Return the value of the FA_sentinel attribute in [attr_list] if it is found *)
+let get_sentinel_func_attribute_value attr_list =
+  (* Sentinel is the only kind of attributes *)
+  let is_sentinel a = true in
+  try
+    match list_find is_sentinel attr_list with
+    | FA_sentinel (sentinel, null_pos) -> Some (sentinel, null_pos)
+  with Not_found -> None
+
 (** current language *)
 let curr_language = ref C_CPP
 

infer/src/backend/sil.mli

@@ -43,6 +43,9 @@ type item_annotation = (annotation * bool) list
 type method_annotation =
   item_annotation * item_annotation list
 
+type func_attribute =
+  | FA_sentinel of int * int
+
 (** Visibility modifiers. *)
 type access = Default | Public | Private | Protected
 
@@ -56,6 +59,7 @@ type proc_attributes =
     is_objc_instance_method : bool; (** the procedure is an objective-C instance method *)
     mutable is_synthetic_method : bool; (** the procedure is a synthetic method *)
     language : language;
+    func_attributes : func_attribute list;
     method_annotation : method_annotation;
   }
 
@@ -783,6 +787,9 @@ val item_annotation_is_empty : item_annotation -> bool
 (** Check if the method annodation is empty. *)
 val method_annotation_is_empty : method_annotation -> bool
 
+(** Return the value of the FA_sentinel attribute in [attr_list] if it is found *)
+val get_sentinel_func_attribute_value : func_attribute list -> (int * int) option
+
 (** {2 Pretty Printing} *)
 
 (** Begin change color if using diff printing, return updated printenv and change status *)

infer/src/backend/specs.ml

@@ -775,6 +775,7 @@ let reset_summary call_graph proc_name loc =
     Sil.is_objc_instance_method = false;
     Sil.is_synthetic_method = false;
     Sil.language = !Sil.curr_language;
+    Sil.func_attributes = [];
     Sil.method_annotation = Sil.method_annotation_empty;
   } in
   init_summary (

infer/src/clang/cEnum_decl.ml

@@ -21,6 +21,7 @@ let create_empty_procdesc () =
       Sil.is_objc_instance_method = false;
       Sil.is_synthetic_method = false;
       Sil.language = Sil.C_CPP;
+      Sil.func_attributes = [];
       Sil.method_annotation = Sil.method_annotation_empty;
     } in
   create {

infer/src/clang/cMethod_decl.ml

@@ -73,7 +73,8 @@ struct
     let qt = get_return_type function_method_decl_info in
     let is_instance_method = is_instance_method function_method_decl_info is_instance is_anonym_block in
     let parameters = get_parameters function_method_decl_info in
-    CMethod_signature.make_ms procname parameters qt source_range is_instance_method
+    let attributes = decl_info.Clang_ast_t.di_attributes in
+    CMethod_signature.make_ms procname parameters qt attributes source_range is_instance_method
 
   let create_function_signature di fdecl_info name qt is_instance anonym_block_opt =
     let procname, is_anonym_block =
@@ -140,7 +141,9 @@ struct
         let curr_class = if is_anonym_block then curr_class else CContext.ContextNoCls in
         add_method tenv cg cfg curr_class procname namespace [body] is_objc_method is_instance
           captured_vars is_anonym_block
-    | None, ms -> CMethod_signature.add ms
+    | None, ms ->
+      CMethod_trans.create_local_procdesc cfg tenv ms [] captured_vars false;
+      CMethod_signature.add ms
 
   let process_objc_method_decl tenv cg cfg namespace curr_class decl_info method_name method_decl_info =
     let class_name = CContext.get_curr_class_name curr_class in

infer/src/clang/cMethod_signature.ml

@@ -10,6 +10,7 @@ type method_signature = {
   _name : Procname.t;
   _args : (string * string) list; (* (name, type) *)
   _ret_type : string;
+  _attributes : Clang_ast_t.attribute list;
   _loc : Clang_ast_t.source_range;
   _is_instance : bool
 }
@@ -23,6 +24,9 @@ let ms_get_args ms =
 let ms_get_ret_type ms =
   ms._ret_type
 
+let ms_get_attributes ms =
+  ms._attributes
+
 let ms_get_loc ms =
   ms._loc
 
@@ -33,23 +37,18 @@ type methodMap = method_signature Procname.Map.t
 
 let methodMap = ref Procname.Map.empty
 
-let make_ms procname args ret_type loc is_instance =
+let make_ms procname args ret_type attributes loc is_instance =
   let meth_signature = {
     _name = procname;
     _args = args;
     _ret_type = ret_type;
+    _attributes = attributes;
     _loc = loc;
     _is_instance = is_instance } in
   meth_signature
 
 let replace_name_ms ms name =
-  let meth_signature = {
-    _name = name;
-    _args = ms._args;
-    _ret_type = ms._ret_type;
-    _loc = ms._loc;
-    _is_instance = ms._is_instance } in
-  meth_signature
+  { ms with _name = name }
 
 let ms_to_string ms =
   "Method "^(Procname.to_string ms._name)^" "^

infer/src/clang/cMethod_signature.mli

@@ -20,12 +20,14 @@ val ms_get_args : method_signature -> (string * string) list
 
 val ms_get_ret_type : method_signature -> string
 
+val ms_get_attributes : method_signature -> Clang_ast_t.attribute list
+
 val ms_get_loc : method_signature -> Clang_ast_t.source_range
 
 val ms_is_instance : method_signature -> bool
 
-val make_ms : Procname.t -> (string * string) list -> string -> Clang_ast_t.source_range ->
-bool -> method_signature
+val make_ms : Procname.t -> (string * string) list -> string -> Clang_ast_t.attribute list ->
+Clang_ast_t.source_range -> bool -> method_signature
 
 val replace_name_ms : method_signature -> Procname.t -> method_signature
 

infer/src/clang/cMethod_trans.ml

@@ -129,11 +129,22 @@ let get_return_type tenv ms =
   CTypes_decl.qual_type_to_sil_type tenv
     (Ast_expressions.create_qual_type (CTypes.get_function_return_type qt))
 
+let sil_func_attributes_of_attributes attrs =
+  let rec do_translation acc al = match al with
+    | [] -> list_rev acc
+    | Clang_ast_t.SentinelAttr attribute_info::tl ->
+      (* TODO(t7466561) right now the clang plugin does not emit attribute arguments *)
+      (* so we default to (0,0) --the default sentinel values. *)
+      do_translation (Sil.FA_sentinel(0,0)::acc) tl
+    | _::tl -> do_translation acc tl in
+  do_translation [] attrs
+
 (** Creates a procedure description. *)
 let create_local_procdesc cfg tenv ms fbody captured is_objc_inst_method =
   let defined = not ((list_length fbody) == 0) in
   let procname = CMethod_signature.ms_get_name ms in
   let pname = Procname.to_string procname in
+  let attributes = sil_func_attributes_of_attributes (CMethod_signature.ms_get_attributes ms) in
   let create_new_procdesc () =
     let formals = get_formal_parameters tenv ms in
     let captured_str = list_map (fun (s, t, _) -> (Mangled.to_string s, t)) captured in
@@ -159,6 +170,7 @@ let create_local_procdesc cfg tenv ms fbody captured is_objc_inst_method =
           Sil.is_objc_instance_method = is_objc_inst_method;
           Sil.is_synthetic_method = false;
           Sil.language = Sil.C_CPP;
+          Sil.func_attributes = attributes;
           Sil.method_annotation = Sil.method_annotation_empty;
         } in
       create {
@@ -211,6 +223,7 @@ let create_external_procdesc cfg procname is_objc_inst_method type_opt =
             Sil.is_objc_instance_method = is_objc_inst_method;
             Sil.is_synthetic_method = false;
             Sil.language = Sil.C_CPP;
+            Sil.func_attributes = [];
             Sil.method_annotation = Sil.method_annotation_empty;
           } in
         create {

infer/src/clang/cTrans_models.ml

@@ -117,13 +117,13 @@ let is_objc_memory_model_controlled o =
   Core_foundation_model.is_objc_memory_model_controlled o
 
 let get_predefined_ms_method condition class_name method_name mk_procname
-    arguments return_type builtin =
+    arguments return_type attributes builtin =
   if condition then
     let procname =
       match builtin with
       | Some procname -> procname
       | None -> mk_procname class_name method_name in
-    let ms = CMethod_signature.make_ms procname arguments return_type
+    let ms = CMethod_signature.make_ms procname arguments return_type attributes
         (Ast_expressions.dummy_source_range ()) false in
     Some ms
   else None
@@ -131,7 +131,7 @@ let get_predefined_ms_method condition class_name method_name mk_procname
 let get_predefined_ms_stringWithUTF8String class_name method_name mk_procname =
   let condition = class_name = nsstring_cl && method_name = string_with_utf8_m in
   get_predefined_ms_method condition class_name method_name mk_procname [("x", "char *")]
-    id_cl None
+    id_cl [] None
 
 let get_predefined_ms_retain_release class_name method_name mk_procname =
   let condition = is_retain_or_release method_name in
@@ -139,18 +139,18 @@ let get_predefined_ms_retain_release class_name method_name mk_procname =
     if is_retain_method method_name || is_autorelease_method method_name
     then id_cl else void in
   get_predefined_ms_method condition nsobject_cl method_name mk_procname
-    [(self, class_name)] return_type (get_builtinname method_name)
+    [(self, class_name)] return_type [] (get_builtinname method_name)
 
 let get_predefined_ms_autoreleasepool_init class_name method_name mk_procname =
   let condition = (method_name = init) && (class_name = nsautorelease_pool_cl) in
   get_predefined_ms_method condition class_name method_name mk_procname
-    [(self, class_name)] void None
+    [(self, class_name)] void [] None
 
 let get_predefined_ms_nsautoreleasepool_release class_name method_name mk_procname =
   let condition = (method_name = release || method_name = drain) &&
     (class_name = nsautorelease_pool_cl) in
   get_predefined_ms_method condition class_name method_name mk_procname [(self, class_name)]
-    void (Some SymExec.ModelBuiltins.__objc_release_autorelease_pool)
+    void [] (Some SymExec.ModelBuiltins.__objc_release_autorelease_pool)
 
 let get_predefined_model_method_signature class_name method_name mk_procname =
   match get_predefined_ms_nsautoreleasepool_release class_name method_name mk_procname with

infer/src/harness/inhabit.ml

@@ -285,6 +285,7 @@ let add_harness_to_cg harness_name harness_cfg harness_node loc cg tenv =
         Sil.is_objc_instance_method = false;
         Sil.is_synthetic_method = false;
         Sil.language = Sil.Java;
+        Sil.func_attributes = [];
         Sil.method_annotation = Sil.method_annotation_empty;
       } in
     create {
@@ -335,6 +336,7 @@ let setup_harness_cfg harness_name harness_cfg env proc_file_map tenv =
         Sil.is_objc_instance_method = false;
         Sil.is_synthetic_method = false;
         Sil.language = Sil.Java;
+        Sil.func_attributes = [];
         Sil.method_annotation = Sil.method_annotation_empty;
       } in
     create {

infer/src/java/jTrans.ml

@@ -295,6 +295,7 @@ let create_local_procdesc program linereader cfg tenv node m =
                   Sil.is_objc_instance_method = false;
                   Sil.is_synthetic_method = am.Javalib.am_synthetic;
                   Sil.language = Sil.Java;
+                  Sil.func_attributes = [];
                   Sil.method_annotation = method_annotation;
                 } in
               create {
@@ -329,6 +330,7 @@ let create_local_procdesc program linereader cfg tenv node m =
                   Sil.is_objc_instance_method = false;
                   Sil.is_synthetic_method = cm.Javalib.cm_synthetic;
                   Sil.language = Sil.Java;
+                  Sil.func_attributes = [];
                   Sil.method_annotation = method_annotation;
                 } in
               create {
@@ -364,6 +366,7 @@ let create_local_procdesc program linereader cfg tenv node m =
                   Sil.is_objc_instance_method = false;
                   Sil.is_synthetic_method = cm.Javalib.cm_synthetic;
                   Sil.language = Sil.Java;
+                  Sil.func_attributes = [];
                   Sil.method_annotation = method_annotation;
                 } in
               create {
@@ -418,6 +421,7 @@ let create_external_procdesc program cfg tenv cn ms method_annotation is_static
           Sil.is_objc_instance_method = false;
           Sil.is_synthetic_method = false;
           Sil.language = Sil.Java;
+          Sil.func_attributes = [];
           Sil.method_annotation = method_annotation;
         } in
       create {