From: Piotr Trojanek <troja...@adacore.com>
In general, protected subprograms are only eligible for a lock-free
expansion if they do not reference global assignable objects.
However, it seems reasonable to ignore references to variables in
System.Scalar_Values, which are generated when pragma Initialize_Scalars
is active. Such references appear, for example, when protected
subprogram has formal parameters of mode out.
gcc/ada/
* sem_ch9.adb (Satisfies_Lock_Free_Requirements): Ignore
references to global variables inserted due to pragma
Initialize_Scalars.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/sem_ch9.adb | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/gcc/ada/sem_ch9.adb b/gcc/ada/sem_ch9.adb
index 5dee216256c..e43e3ae0b41 100644
--- a/gcc/ada/sem_ch9.adb
+++ b/gcc/ada/sem_ch9.adb
@@ -474,6 +474,12 @@ package body Sem_Ch9 is
begin
-- Prohibit references to non-constant entities
-- outside the protected subprogram scope.
+ --
+ -- References to variables in System.Scalar_Values
+ -- generated because of pragma Initialize_Scalars are
+ -- allowed, because once those variables are
+ -- initialized by the binder-generated code, they
+ -- behave like constants.
if Is_Assignable (Id)
and then not
@@ -482,6 +488,9 @@ package body Sem_Ch9 is
Scope_Within_Or_Same
(Scope (Id),
Protected_Body_Subprogram (Sub_Id))
+ and then not
+ (Is_RTU (Scope (Id), System_Scalar_Values)
+ and then not Comes_From_Source (N))
then
if Lock_Free_Given then
Error_Msg_NE
--
2.34.1
