The patch implements the No_Task_Parts aspect, which says that a type and extensions of it cannot contain tasks.
In addition, we optimize away tasking-related code for T'Class when T
has No_Task_Parts. This is mostly just an efficiency improvement, but it
fixes a bug in one obscure case: The expanded code for a "for ... of"
loop contains an object of a class-wide type (e.g.
Reversible_Iterator'Class), so the compiler would normally generate
tasking-related calls, which are blocking, so if the procedure
containing "for ... of" is called from a protected object, and
Detect_Blocking is enabled, Program_Error will be raised. These compiler
changes, along with adding No_Task_Parts to the iterator interfaces,
fixes that bug.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* aspects.ads (No_Task_Parts): New aspect.
* snames.ads-tmpl: Add the aspect name.
* exp_ch6.adb (Might_Have_Tasks): Return False if this is a
class-wide type whose specific type has No_Task_Parts.
* freeze.adb (Check_No_Parts_Violations): This is an adaptation
of the procedure formerly known as
Check_No_Controlled_Parts_Violations, which now supports both
No_Controlled_Parts and No_Task_Parts. It takes a parameter
indicating which aspect is being checked.
(Freeze_Entity): Call Check_No_Parts_Violations for both
aspects.
* sem_ch13.adb (Analyze_Aspect_Specifications): The code for
Aspect_No_Controlled_Parts already works as is with
Aspect_No_Task_Parts.
* libgnat/a-iteint.ads: Add No_Task_Parts aspect to the two
iterator iterfaces.
* doc/gnat_rm/implementation_defined_aspects.rst: Add
documentation for the No_Task_Parts aspect.
* gnat_rm.texi: Regenerate.
patch.diff.gz
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