This patch refines the checks and the corresponding error messsages on
the legality of instantiations where some formal objects and their
corresponding actuals may carry Atomic, Atonic_Components, Volatile,
Volatile_Components, Independent, or Independent_Components aspect
specifications. The legality rules require exact match between formal
and actual for the first four aspects, but not for the last two. For
Atomic_Components and Volatile_Components we also check whether the
actual is of an array type with the corresponding: aspect on its
component type.
Tested on x86_64-pc-linux-gnu, committed on trunk
2020-06-09 Ed Schonberg <schonb...@adacore.com>
gcc/ada/
* sem_ch12.adb (Check_Shared_Variable_Control_Aspects): Require
exact match between formal and actual for aspects Atomic,
Atomic_Component, Volatile, and Volatile_Components.--- gcc/ada/sem_ch12.adb
+++ gcc/ada/sem_ch12.adb
@@ -12398,21 +12398,15 @@ package body Sem_Ch12 is
procedure Check_Shared_Variable_Control_Aspects is
begin
if Ada_Version >= Ada_2020 then
- if Is_Atomic (A_Gen_T) and then not Is_Atomic (Act_T) then
+ if Is_Atomic (A_Gen_T) /= Is_Atomic (Act_T) then
Error_Msg_NE
- ("actual for& must be an atomic type", Actual, A_Gen_T);
+ ("actual for& has different Atomic aspect", Actual, A_Gen_T);
end if;
- if Is_Volatile (A_Gen_T) and then not Is_Volatile (Act_T) then
+ if Is_Volatile (A_Gen_T) /= Is_Volatile (Act_T) then
Error_Msg_NE
- ("actual for& must be a Volatile type", Actual, A_Gen_T);
- end if;
-
- if
- Is_Independent (A_Gen_T) and then not Is_Independent (Act_T)
- then
- Error_Msg_NE
- ("actual for& must be an Independent type", Actual, A_Gen_T);
+ ("actual for& has different Volatile aspect",
+ Actual, A_Gen_T);
end if;
-- We assume that an array type whose atomic component type
@@ -12420,43 +12414,51 @@ package body Sem_Ch12 is
-- aspect Has_Atomic_Components. This is a reasonable inference
-- from the intent of AI12-0282, and makes it legal to use an
-- actual that does not have the identical aspect as the formal.
+ -- Ditto for volatile components.
- if Has_Atomic_Components (A_Gen_T)
- and then not Has_Atomic_Components (Act_T)
- then
- if Is_Array_Type (Act_T)
- and then Is_Atomic (Component_Type (Act_T))
- then
- null;
+ declare
+ Actual_Atomic_Comp : constant Boolean :=
+ Has_Atomic_Components (Act_T)
+ or else (Is_Array_Type (Act_T)
+ and then Is_Atomic (Component_Type (Act_T)));
+ begin
+ if Has_Atomic_Components (A_Gen_T) /= Actual_Atomic_Comp then
+ Error_Msg_NE
+ ("formal and actual for& must agree on atomic components",
+ Actual, A_Gen_T);
+ end if;
+ end;
- else
+ declare
+ Actual_Volatile_Comp : constant Boolean :=
+ Has_Volatile_Components (Act_T)
+ or else (Is_Array_Type (Act_T)
+ and then Is_Volatile (Component_Type (Act_T)));
+ begin
+ if Has_Volatile_Components (A_Gen_T) /= Actual_Volatile_Comp
+ then
Error_Msg_NE
- ("actual for& must have atomic components",
+ ("actual for& must have volatile components",
Actual, A_Gen_T);
end if;
- end if;
+ end;
- if Has_Independent_Components (A_Gen_T)
- and then not Has_Independent_Components (Act_T)
+ -- The following two aspects do not require exact matching,
+ -- but only one-way agreement. See RM C.6.
+
+ if Is_Independent (A_Gen_T) and then not Is_Independent (Act_T)
then
Error_Msg_NE
- ("actual for& must have independent components",
- Actual, A_Gen_T);
+ ("actual for& must have Independent aspect specified",
+ Actual, A_Gen_T);
end if;
- if Has_Volatile_Components (A_Gen_T)
- and then not Has_Volatile_Components (Act_T)
+ if Has_Independent_Components (A_Gen_T)
+ and then not Has_Independent_Components (Act_T)
then
- if Is_Array_Type (Act_T)
- and then Is_Volatile (Component_Type (Act_T))
- then
- null;
-
- else
- Error_Msg_NE
- ("actual for& must have volatile components",
- Actual, A_Gen_T);
- end if;
+ Error_Msg_NE
+ ("actual for& must have Independent_Components specified",
+ Actual, A_Gen_T);
end if;
end if;
end Check_Shared_Variable_Control_Aspects;
