Add return parameter to functions returning structs

Summary:
public
Introduce additional parameter for functions returning struct types - instead of returning it, populate output parameter.
This diff just changes method signature, there are more coming

Reviewed By: jberdine

Differential Revision: D2864842

fb-gh-sync-id: 52fc12c

infer/src/clang/cFrontend_config.ml

@@ -33,6 +33,8 @@ let self = "self"
 
 let this = "this"
 
+let return_param = "__return_param"
+
 let alloc = "alloc"
 
 let malloc = "malloc"

infer/src/clang/cFrontend_config.mli

@@ -53,6 +53,8 @@ val self : string
 
 val this : string
 
+val return_param : string
+
 val nsstring_cl : string
 
 val nsobject_cl : string

infer/src/clang/cMethod_decl.ml

@@ -71,7 +71,7 @@ struct
       | Some (outer_context, _, _, captured_vars) -> captured_vars, Some outer_context
       | None -> [], None in
     let ms, body_opt, extra_instrs =
-      CMethod_trans.method_signature_of_decl func_decl block_data_opt in
+      CMethod_trans.method_signature_of_decl tenv func_decl block_data_opt in
     match body_opt with
     | Some body -> (* Only in the case the function declaration has a defined body we create a procdesc *)
         let procname = CMethod_signature.ms_get_name ms in
@@ -82,7 +82,7 @@ struct
 
   let process_method_decl tenv cg cfg curr_class meth_decl ~is_objc =
     let ms, body_opt, extra_instrs =
-      CMethod_trans.method_signature_of_decl meth_decl None in
+      CMethod_trans.method_signature_of_decl tenv meth_decl None in
     match body_opt with
     | Some body ->
         let is_instance = CMethod_signature.ms_is_instance ms in

infer/src/clang/cMethod_trans.ml

@@ -41,6 +41,13 @@ let is_instance_method function_method_decl_info =
   | ObjC_Meth_decl_info (method_decl_info, _) ->
       method_decl_info.Clang_ast_t.omdi_is_instance_method
 
+let get_original_return_type function_method_decl_info =
+  match function_method_decl_info with
+  | Func_decl_info (_, typ, _)
+  | Cpp_Meth_decl_info (_, _, _, typ)
+  | Block_decl_info (_, typ, _) -> CTypes.return_type_of_function_type typ
+  | ObjC_Meth_decl_info (method_decl_info, _) -> method_decl_info.Clang_ast_t.omdi_result_type
+
 let get_class_param function_method_decl_info =
   if (is_instance_method function_method_decl_info) then
     match function_method_decl_info with
@@ -53,6 +60,19 @@ let get_class_param function_method_decl_info =
     | _ -> []
   else []
 
+let should_add_return_param return_type =
+  match return_type with
+  | Sil.Tstruct _ -> false (* will return true once everything is in place *)
+  | _ -> false
+
+let get_return_param tenv function_method_decl_info =
+  let return_type_ptr = get_original_return_type function_method_decl_info in
+  let return_typ = CTypes_decl.type_ptr_to_sil_type tenv return_type_ptr in
+  if should_add_return_param return_typ then
+    [(CFrontend_config.return_param, Ast_expressions.create_pointer_type return_type_ptr)]
+  else
+    []
+
 let get_param_decls function_method_decl_info =
   match function_method_decl_info with
   | Func_decl_info (function_decl_info, _, _)
@@ -68,30 +88,33 @@ let get_language function_method_decl_info =
   | ObjC_Meth_decl_info _ -> CFrontend_config.OBJC
   | Block_decl_info _ -> CFrontend_config.OBJC
 
-let get_parameters function_method_decl_info =
+(** Returns parameters of a function/method. They will have following order:
+    1. self/this parameter (optional, only for methods)
+    2. normal parameters
+    3. return parameter (optional) *)
+let get_parameters tenv function_method_decl_info =
   let par_to_ms_par par =
     match par with
     | Clang_ast_t.ParmVarDecl (decl_info, name_info, type_ptr, var_decl_info) ->
         let name = name_info.Clang_ast_t.ni_name in
         (name, type_ptr)
     | _ -> assert false in
-
   let pars = IList.map par_to_ms_par (get_param_decls function_method_decl_info) in
-  get_class_param function_method_decl_info @ pars
+  get_class_param function_method_decl_info @ pars @ get_return_param tenv function_method_decl_info
 
-let get_return_type function_method_decl_info =
-  match function_method_decl_info with
-  | Func_decl_info (_, typ, _)
-  | Cpp_Meth_decl_info (_, _, _, typ)
-  | Block_decl_info (_, typ, _) -> CTypes.return_type_of_function_type typ
-  | ObjC_Meth_decl_info (method_decl_info, _) -> method_decl_info.Clang_ast_t.omdi_result_type
+let get_return_type tenv function_method_decl_info =
+  let return_type_ptr = get_original_return_type function_method_decl_info in
+  let return_typ = CTypes_decl.type_ptr_to_sil_type tenv return_type_ptr in
+  if should_add_return_param return_typ then
+    Ast_expressions.create_void_type
+  else return_type_ptr
 
-let build_method_signature decl_info procname function_method_decl_info is_anonym_block
+let build_method_signature tenv decl_info procname function_method_decl_info is_anonym_block
     parent_pointer pointer_to_property_opt =
   let source_range = decl_info.Clang_ast_t.di_source_range in
-  let tp = get_return_type function_method_decl_info in
+  let tp = get_return_type tenv function_method_decl_info in
   let is_instance_method = is_instance_method function_method_decl_info in
-  let parameters = get_parameters function_method_decl_info in
+  let parameters = get_parameters tenv function_method_decl_info in
   let attributes = decl_info.Clang_ast_t.di_attributes in
   let lang = get_language function_method_decl_info in
   CMethod_signature.make_ms
@@ -111,7 +134,7 @@ let get_init_list_instrs method_decl_info =
   let create_custom_instr construct_instr = `CXXConstructorInit construct_instr in
   IList.map create_custom_instr method_decl_info.Clang_ast_t.xmdi_cxx_ctor_initializers
 
-let method_signature_of_decl meth_decl block_data_opt =
+let method_signature_of_decl tenv meth_decl block_data_opt =
   let open Clang_ast_t in
   match meth_decl, block_data_opt with
   | FunctionDecl (decl_info, name_info, tp, fdi), _ ->
@@ -120,7 +143,7 @@ let method_signature_of_decl meth_decl block_data_opt =
       let func_decl = Func_decl_info (fdi, tp, language) in
       let function_info = Some (decl_info, fdi) in
       let procname = General_utils.mk_procname_from_function name function_info tp language in
-      let ms = build_method_signature decl_info procname func_decl false None None in
+      let ms = build_method_signature tenv decl_info procname func_decl false None None in
       let extra_instrs = get_assume_not_null_calls fdi.Clang_ast_t.fdi_parameters in
       ms, fdi.Clang_ast_t.fdi_body, extra_instrs
   | CXXMethodDecl (decl_info, name_info, tp, fdi, mdi), _
@@ -131,7 +154,7 @@ let method_signature_of_decl meth_decl block_data_opt =
       let procname = General_utils.mk_procname_from_cpp_method class_name method_name tp in
       let method_decl = Cpp_Meth_decl_info (fdi, mdi, class_name, tp)  in
       let parent_pointer = decl_info.Clang_ast_t.di_parent_pointer in
-      let ms = build_method_signature decl_info procname method_decl false parent_pointer
+      let ms = build_method_signature tenv decl_info procname method_decl false parent_pointer
           None in
       let non_null_instrs = get_assume_not_null_calls fdi.Clang_ast_t.fdi_parameters in
       let init_list_instrs = get_init_list_instrs mdi in (* it will be empty for methods *)
@@ -148,22 +171,22 @@ let method_signature_of_decl meth_decl block_data_opt =
         match mdi.Clang_ast_t.omdi_property_decl with
         | Some decl_ref -> Some decl_ref.Clang_ast_t.dr_decl_pointer
         | None -> None in
-      let ms = build_method_signature decl_info procname method_decl false
+      let ms = build_method_signature tenv decl_info procname method_decl false
           parent_pointer pointer_to_property_opt in
       let extra_instrs = get_assume_not_null_calls mdi.omdi_parameters in
       ms, mdi.omdi_body, extra_instrs
   | BlockDecl (decl_info, bdi), Some (outer_context, tp, procname, _) ->
       let func_decl = Block_decl_info (bdi, tp, outer_context) in
-      let ms = build_method_signature decl_info procname func_decl true None None in
+      let ms = build_method_signature tenv decl_info procname func_decl true None None in
       let extra_instrs = get_assume_not_null_calls bdi.bdi_parameters in
       ms, bdi.bdi_body, extra_instrs
   | _ -> raise Invalid_declaration
 
-let method_signature_of_pointer pointer =
+let method_signature_of_pointer tenv pointer =
   try
     match Ast_utils.get_decl pointer with
     | Some meth_decl ->
-        let ms, _, _ = method_signature_of_decl meth_decl None in
+        let ms, _, _ = method_signature_of_decl tenv meth_decl None in
         Some ms
     | None -> None
   with Invalid_declaration -> None
@@ -207,10 +230,10 @@ let get_superclass_curr_class context =
   | CContext.ContextProtocol _ -> assert false
 
 (* Gets the class name from a method signature found by clang, if search is successful *)
-let get_class_name_method_call_from_clang obj_c_message_expr_info =
+let get_class_name_method_call_from_clang tenv obj_c_message_expr_info =
   match obj_c_message_expr_info.Clang_ast_t.omei_decl_pointer with
   | Some pointer ->
-      (match method_signature_of_pointer pointer with
+      (match method_signature_of_pointer tenv pointer with
        | Some ms ->
            let class_name = Procname.c_get_class (CMethod_signature.ms_get_name ms) in
            Some class_name
@@ -385,7 +408,7 @@ let create_external_procdesc cfg proc_name is_objc_inst_method type_opt =
 
 let create_procdesc_with_pointer context pointer class_name_opt name tp =
   let open CContext in
-  match method_signature_of_pointer pointer with
+  match method_signature_of_pointer context.tenv pointer with
   | Some callee_ms ->
       ignore (create_local_procdesc context.cfg context.tenv callee_ms [] [] false);
       CMethod_signature.ms_get_name callee_ms

infer/src/clang/cMethod_trans.mli

@@ -20,6 +20,8 @@ type method_call_type =
   | MCNoVirtual
   | MCStatic
 
+val should_add_return_param : Sil.typ -> bool
+
 val create_local_procdesc : Cfg.cfg -> Sil.tenv -> CMethod_signature.method_signature ->
   Clang_ast_t.stmt list -> (Sil.pvar * Sil.typ) list -> bool -> bool
 
@@ -31,12 +33,14 @@ val get_objc_method_data : Clang_ast_t.obj_c_message_expr_info ->
 val get_class_name_method_call_from_receiver_kind : CContext.t ->
   Clang_ast_t.obj_c_message_expr_info -> (Sil.exp * Sil.typ) list -> string
 
-val get_class_name_method_call_from_clang : Clang_ast_t.obj_c_message_expr_info -> string option
+val get_class_name_method_call_from_clang : Sil.tenv -> Clang_ast_t.obj_c_message_expr_info ->
+  string option
 
-val method_signature_of_decl : Clang_ast_t.decl -> CModule_type.block_data option ->
+val method_signature_of_decl : Sil.tenv -> Clang_ast_t.decl -> CModule_type.block_data option ->
   CMethod_signature.method_signature * Clang_ast_t.stmt option * CModule_type.instr_type list
 
-val method_signature_of_pointer : Clang_ast_t.pointer -> CMethod_signature.method_signature option
+val method_signature_of_pointer : Sil.tenv -> Clang_ast_t.pointer ->
+  CMethod_signature.method_signature option
 
 val get_method_name_from_clang : Sil.tenv -> CMethod_signature.method_signature option ->
   CMethod_signature.method_signature option

infer/src/clang/cTrans.ml

@@ -43,7 +43,7 @@ struct
     let method_kind = Procname.objc_method_kind_of_bool is_instance in
     let ms_opt =
       match method_pointer_opt with
-      | Some pointer -> CMethod_trans.method_signature_of_pointer pointer
+      | Some pointer -> CMethod_trans.method_signature_of_pointer context.tenv pointer
       | None -> None in
     let procname =
       match CMethod_trans.get_method_name_from_clang context.tenv ms_opt with
@@ -418,7 +418,7 @@ struct
     Printing.log_out "!!!!! Dealing with method '%s' @." method_name;
     let method_typ = CTypes_decl.type_ptr_to_sil_type context.tenv type_ptr in
     let is_instance_method =
-      match CMethod_trans.method_signature_of_pointer decl_ptr with
+      match CMethod_trans.method_signature_of_pointer context.tenv decl_ptr with
       | Some ms -> CMethod_signature.ms_is_instance ms
       | _ -> true in (* might happen for methods that are not exported yet (some templates). *)
     let extra_exps = if is_instance_method then (
@@ -833,8 +833,8 @@ struct
     else if (selector = CFrontend_config.alloc) || (selector = CFrontend_config.new_str) then
       match receiver_kind with
       | `Class type_ptr ->
-          let class_opt =
-            CMethod_trans.get_class_name_method_call_from_clang obj_c_message_expr_info in
+          let class_opt = CMethod_trans.get_class_name_method_call_from_clang context.tenv
+              obj_c_message_expr_info in
           Some (new_or_alloc_trans trans_state_pri sil_loc si type_ptr class_opt selector)
       | _ -> None
       (* assertions *)