[Ada] Crash in tagged type constructor with task components

[Ada] Crash in tagged type constructor with task components

2020-06-15  Javier Miranda  <miranda@adacore.com>

gcc/ada/

	* restrict.ads (Set_Global_No_Tasking, Global_No_Tasking): New
	subprograms.
	* restrict.adb (Set_Global_No_Tasking, Global_No_Tasking): New
	subprograms.
	* sem_ch3.adb (Access_Definition): Do not skip building masters
	since they may be required for BIP calls.
	(Analyze_Subtype_Declaration): Propagate attribute
	Is_Limited_Record in class-wide subtypes and subtypes with
	cloned subtype attribute; propagate attribute
	Is_Limited_Interface.
	* sem_ch6.adb (Check_Anonymous_Return): Do not skip building
	masters since they may be required for BIP calls. Use
	Build_Master_Declaration to declare the _master variable.
	(Create_Extra_Formals): Add decoration of Has_Master_Entity when
	the _master formal is added.
	* exp_ch3.adb (Init_Formals): Adding formal to decorate it with
	attribute Has_Master_Entity when the _master formal is added.
	(Build_Master): Do not skip building masters since they may be
	required for BIP calls.
	(Expand_N_Object_Declaration): Ensure activation chain and
	master entity for objects initialized with BIP function calls.
	* sem_prag.adb (Process_Restrictions_Or_Restriction_Warnings):
	Adding support to detect and save restriction No_Tasking when
	set in the run-time package System or in a global configuration
	pragmas file.
	* sem_util.adb (Current_Entity_In_Scope): Overload this
	subprogram to allow searching for an entity by its Name.
	* sem_util.ads (Current_Entity_In_Scope): Update comment.
	* exp_ch4.adb (Expand_N_Allocator): Do not skip building masters
	since they may be required for BIP calls.
	* exp_ch6.ads (Might_Have_Tasks): New subprogram.
	* exp_ch6.adb (Make_Build_In_Place_Call_In_Allocator): Add
	support for BIP calls returning objects that may have tasks.
	(Make_Build_In_Place_Call_In_Allocator): Build the activation
	chain if the result might have tasks.
	(Make_Build_In_Place_Iface_Call_In_Allocator): Build the class
	wide master for the result type.
	(Might_Have_Tasks): New subprogram.
	(Needs_BIP_Task_Actuals): Returns False when restriction
	No_Tasking is globally set.
	* exp_ch9.ads (Build_Master_Declaration): New subprogram.
	* exp_ch9.adb (Build_Activation_Chain_Entity): No action
	performed when restriction No_Tasking is globally set.
	(Build_Class_Wide_Master): No action performed when restriction
	No_Tasking is globally set; use Build_Master_Declaration to
	declare the _master variable.
	(Build_Master_Declaration): New subprogram.
	(Build_Master_Entity): No action performed when restriction
	No_Tasking is globally set; added support to handle transient
	scopes and _finalizer routines.
	(Build_Master_Renaming): No action performed when restriction
	No_Tasking is globally set.
	(Build_Task_Activation_Call): Skip generating the call when
	the chain is an ignored ghost entity.
	(Find_Master_Scope): Generalize the code that detects transient
	scopes with master entity.
	* einfo.ads (Has_Nested_Subprogram): Minor comment reformatting.