===================================================================
@@ -5999,8 +5999,9 @@
Renamed : Node_Id;
begin
- -- Check for case of _object.all.field (note that the explicit
- -- dereference gets inserted by analyze/expand of _object.field).
+ -- Check if the name is a component of the protected object. If
+ -- the expander is active, the component has been transformed into
+ -- a renaming of _object.all.component.
if Expander_Active then
Renamed := Renamed_Object (Entity (N));
@@ -6010,7 +6011,7 @@
and then Nkind (Renamed) = N_Selected_Component
and then Chars (Prefix (Prefix (Renamed))) = Name_uObject;
else
- return Scope (Entity (N)) = Current_Scope;
+ return Is_Protected_Component (Entity (N));
end if;
end Is_Simple_Barrier_Name;
@@ -6019,25 +6020,6 @@
---------------------
function Is_Pure_Barrier (N : Node_Id) return Traverse_Result is
- function Is_Count_Attribute (N : Node_Id) return Boolean;
- -- Check whether N is part of an expansion of the Count attribute.
- -- Return True if N represents the expanded function call.
-
- ------------------------
- -- Is_Count_Attribute --
- ------------------------
-
- function Is_Count_Attribute (N : Node_Id) return Boolean is
- begin
- return
- Nkind (N) = N_Function_Call
- and then Present (Original_Node (N))
- and then Nkind (Original_Node (N)) = N_Attribute_Reference
- and then Attribute_Name (Original_Node (N)) = Name_Count;
- end Is_Count_Attribute;
-
- -- Start of processing for Is_Pure_Barrier
-
begin
case Nkind (N) is
when N_Expanded_Name
@@ -6045,11 +6027,8 @@
=>
if No (Entity (N)) then
return Abandon;
- end if;
- if Present (Parent (N))
- and then Is_Count_Attribute (Parent (N))
- then
+ elsif Is_Universal_Numeric_Type (Entity (N)) then
return OK;
end if;
@@ -6062,25 +6041,36 @@
=>
return OK;
- when E_Component
- | E_Variable
- =>
- -- A variable in the protected type is expanded as a
- -- component.
+ when E_Component =>
+ return OK;
+ when E_Variable =>
if Is_Simple_Barrier_Name (N) then
return OK;
end if;
+ when E_Function =>
+
+ -- The count attribute has been transformed into run-time
+ -- calls.
+
+ if Is_RTE (Entity (N), RE_Protected_Count)
+ or else Is_RTE (Entity (N), RE_Protected_Count_Entry)
+ then
+ return OK;
+ end if;
+
when others =>
null;
end case;
when N_Function_Call =>
- if Is_Count_Attribute (N) then
- return OK;
- end if;
+ -- Function call checks are carried out as part of the analysis
+ -- of the function call name.
+
+ return OK;
+
when N_Character_Literal
| N_Integer_Literal
| N_Real_Literal
@@ -6097,6 +6087,27 @@
when N_Short_Circuit =>
return OK;
+ when N_Indexed_Component
+ | N_Selected_Component
+ =>
+ if not Is_Access_Type (Etype (Prefix (N))) then
+ return OK;
+ end if;
+
+ when N_Type_Conversion =>
+
+ -- Conversions to Universal_Integer will not raise constraint
+ -- errors.
+
+ if Cannot_Raise_Constraint_Error (N)
+ or else Etype (N) = Universal_Integer
+ then
+ return OK;
+ end if;
+
+ when N_Unchecked_Type_Conversion =>
+ return OK;
+
when others =>
null;
end case;
This patch permits the use of type conversions and components of objects subject to the following conditions: type conversions cannot potentially raise contraint errors and access types cannot be dereferenced. These additions provide greater functionality to users while respecting the aims of the Pure_Barrier restriction: side effects, exceptions, and recursion cannot occur during the evaluation of the barriers. In practise this patch allows users to compare the result of the Count attribute with a literal or named number, and reference components of array or record types in barriers. The following must compile quietly: --- package Test_PO is type BooT is record Far : Integer; end record; type FooT is record Bar : BooT; end record; protected PO is entry A; entry B; private Foo : FooT; end PO; end Test_PO; --- pragma Restrictions (Pure_Barriers); package body Test_PO is protected body PO is entry A when A'Count > 5 is begin null; end A; entry B when Foo.Bar.Far = 5 is begin null; end B; end PO; end Test_PO; Tested on x86_64-pc-linux-gnu, committed on trunk 2017-09-08 Patrick Bernardi <bernardi@adacore.com> * exp_ch9.adb (Is_Pure_Barrier): Allow type conversions and components of objects. Simplified the detection of the Count attribute by identifying the corresponding run-time calls.