Simplify builtin function detection during translation

Summary:
Given that mangling now respects `extern "C" {}` declarations, pnames of C function will have no mangling and we don't need to discard mangled part from procname.
Move `malloc` detection to `get_builtin_pname_opt` function (together with all others)

Reviewed By: dulmarod

Differential Revision: D3804402

fbshipit-source-id: 9ae9991

infer/models/c/src/infer_builtins.h

@@ -14,6 +14,12 @@
 #include <stdlib.h>
 #include <time.h>
 
+#ifdef __cplusplus
+// specify C linkage to avoid mangling of names of infer builtins
+// they need to have plain C name so backend can recognise it
+extern "C" {
+#endif
+
 // model returning an arbitrary (nondeterministic) short
 short __infer_nondet_short();
 
@@ -72,3 +78,7 @@ extern void __set_array_length(void* ptr, size_t size);
 // builtin: set the flag to the given value for the procedure where this call
 // appears
 extern void __infer_set_flag(char* flag, char* value);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif

infer/src/clang/ComponentKit.ml

@@ -83,7 +83,7 @@ let mutable_local_vars_advice context decl =
       let is_const = qual_type.qt_is_const || is_const_ref in
       let condition = context.CLintersContext.is_ck_translation_unit
                       && Ast_utils.is_in_main_file decl
-                      && General_utils.is_objc_extention
+                      && General_utils.is_objc_extension
                       && (not (Ast_utils.is_syntactically_global_var decl))
                       && (not is_const) in
       if condition then

infer/src/clang/cFrontend_checkers.ml

@@ -200,7 +200,7 @@ let global_var_init_with_calls_warning _ decl =
     match Clang_ast_proj.get_named_decl_tuple decl with
     | Some (di, ndi) -> di, ndi.ni_name
     | None -> assert false (* we cannot be here *) in
-  let condition = General_utils.is_objc_extention
+  let condition = General_utils.is_objc_extension
                   && Ast_utils.is_syntactically_global_var decl
                   && (not (Ast_utils.is_const_expr_var decl))
                   && is_initialized_with_expensive_call decl in

infer/src/clang/cFrontend_utils.ml

@@ -589,7 +589,7 @@ struct
   let is_cpp_translation =
     Config.clang_lang = Config.CPP || Config.clang_lang = Config.OBJCPP
 
-  let is_objc_extention =
+  let is_objc_extension =
     Config.clang_lang = Config.OBJC || Config.clang_lang = Config.OBJCPP
 
   let rec get_mangled_method_name function_decl_info method_decl_info =

infer/src/clang/cFrontend_utils.mli

@@ -231,6 +231,6 @@ sig
   val is_cpp_translation : bool
 
   (** true if Config.clang_lang is ObjC or ObjC++ *)
-  val is_objc_extention : bool
+  val is_objc_extension : bool
 
 end

infer/src/clang/cTrans.ml

@@ -466,6 +466,9 @@ struct
         Some ModelBuiltins.__objc_release_cf
     | _ when CTrans_models.is_retain_builtin name type_ptr ->
         Some ModelBuiltins.__objc_retain_cf
+    | _ when name = CFrontend_config.malloc &&
+             General_utils.is_objc_extension ->
+        Some ModelBuiltins.malloc_no_fail
     | _ -> None
 
 
@@ -484,21 +487,9 @@ struct
     (* If we are not translating a callee expression, *)
     (* then the address of the function is being taken.*)
     (* As e.g. in fun_ptr = foo; *)
-    let name = Procname.to_string pname in
-    let non_mangled_func_name =
-      if name = CFrontend_config.malloc &&
-         (Config.clang_lang = Config.OBJC ||
-          Config.clang_lang = Config.OBJCPP) then
-        ModelBuiltins.malloc_no_fail
-      else Procname.from_string_c_fun name in
-    let is_builtin = Builtin.is_registered non_mangled_func_name in
-    if is_builtin then (* malloc, free, exit, scanf, ... *)
-      { empty_res_trans with exps = [(Exp.Const (Const.Cfun non_mangled_func_name), typ)] }
-    else
-      begin
-        if address_of_function then Cfg.set_procname_priority context.cfg pname;
-        { empty_res_trans with exps = [(Exp.Const (Const.Cfun pname), typ)] }
-      end
+    let is_builtin = Builtin.is_registered pname in
+    if address_of_function && not is_builtin then Cfg.set_procname_priority context.cfg pname;
+    { empty_res_trans with exps = [(Exp.Const (Const.Cfun pname), typ)] }
 
   let field_deref_trans trans_state stmt_info pre_trans_result decl_ref ~is_constructor_init =
     let open CContext in