When a protected subprogram invokes a function that returns a limited
type, and the sources are compiled with pragma Detect_ Blocking, the
code generated by the compiler erroneously invokes the runtime service
Activate_Tasks, call which is detected by the runtime as a potentially
blocking call (as described in RM 9.5.1) and causes Program_Error to be
raised raised at runtime.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* exp_ch9.adb (Build_Task_Activation_Call): Do not generate a
call to activate tasks if we are within the scope of a protected
type and pragma Detect_Blocking is active.
diff --git a/gcc/ada/exp_ch9.adb b/gcc/ada/exp_ch9.adb
--- a/gcc/ada/exp_ch9.adb
+++ b/gcc/ada/exp_ch9.adb
@@ -4960,6 +4960,18 @@ package body Exp_Ch9 is
if No (Chain) or else Is_Ignored_Ghost_Entity (Chain) then
return;
+
+ -- The availability of the activation chain entity does not ensure
+ -- that we have tasks to activate because it may have been declared
+ -- by the frontend to pass a required extra formal to a build-in-place
+ -- subprogram call. If we are within the scope of a protected type and
+ -- pragma Detect_Blocking is active we can assume that no tasks will be
+ -- activated; if tasks are created in a protected object and this pragma
+ -- is active then the frontend emits a warning and Program_Error is
+ -- raised at runtime.
+
+ elsif Detect_Blocking and then Within_Protected_Type (Current_Scope) then
+ return;
end if;
-- The location of the activation call must be as close as possible to