------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- S Y S T E M . T A S K I N G . R E S T R I C T E D . S T A G E S -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2020, Free Software Foundation, Inc. -- -- -- -- GNARL is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is a simplified version of the System.Tasking.Stages package, -- intended to be used in a restricted run time. -- This package represents the high level tasking interface used by the -- compiler to expand Ada 95 tasking constructs into simpler run time calls -- (aka GNARLI, GNU Ada Run-time Library Interface) -- Note: the compiler generates direct calls to this interface, via Rtsfind. -- Any changes to this interface may require corresponding compiler changes -- in exp_ch9.adb and possibly exp_ch7.adb -- The restricted GNARLI is also composed of System.Protected_Objects and -- System.Protected_Objects.Single_Entry with System.Parameters; with System.Secondary_Stack; with System.Task_Info; package System.Tasking.Restricted.Stages is pragma Elaborate_Body; --------------------------------- -- Compiler Interface (GNARLI) -- --------------------------------- -- The compiler will expand in the GNAT tree the following construct: -- task type T (Discr : Integer); -- task body T is -- ...declarations, possibly some controlled... -- begin -- ...B...; -- end T; -- T1 : T (1); -- as follows: -- task type t (discr : integer); -- tE : aliased boolean := false; -- tZ : size_type := unspecified_size; -- type tV (discr : integer) is limited record -- _task_id : task_id; -- _atcb : aliased system__tasking__ada_task_control_block (0); -- end record; -- procedure tB (_task : access tV); -- freeze tV [ -- procedure tVIP (_init : in out tV; _master : master_id; -- _chain : in out activation_chain; _task_name : in string; -- discr : integer) is -- begin -- _init.discr := discr; -- _init._task_id := null; -- system__tasking__ada_task_control_blockIP (_init._atcb, 0); -- _init._task_id := _init._atcb'unchecked_access; -- create_restricted_task (unspecified_priority, tZ, -- unspecified_task_info, unspecified_cpu, -- task_procedure_access!(tB'address), _init'address, -- tE'unchecked_access, _task_name, _init._task_id); -- return; -- end tVIP; -- _chain : aliased activation_chain; -- activation_chainIP (_chain); -- procedure tB (_task : access tV) is -- discr : integer renames _task.discr; -- procedure _clean is -- begin -- complete_restricted_task; -- finalize_list (F14b); -- return; -- end _clean; -- begin -- ...declarations... -- complete_restricted_activation; -- ...B...; -- return; -- at end -- _clean; -- end tB; -- tE := true; -- t1 : t (1); -- t1S : constant String := "t1"; -- tIP (t1, 3, _chain, t1S, 1); Partition_Elaboration_Policy : Character := 'C'; pragma Export (C, Partition_Elaboration_Policy, "__gnat_partition_elaboration_policy"); -- Partition elaboration policy. Value can be either 'C' for concurrent, -- which is the default or 'S' for sequential. This value can be modified -- by the binder generated code, before calling elaboration code. procedure Create_Restricted_Task (Priority : Integer; Stack_Address : System.Address; Stack_Size : System.Parameters.Size_Type; Sec_Stack_Address : System.Secondary_Stack.SS_Stack_Ptr; Sec_Stack_Size : System.Parameters.Size_Type; Task_Info : System.Task_Info.Task_Info_Type; CPU : Integer; State : Task_Procedure_Access; Discriminants : System.Address; Elaborated : Access_Boolean; Chain : in out Activation_Chain; Task_Image : String; Created_Task : Task_Id); -- Compiler interface only. Do not call from within the RTS. -- This must be called to create a new task, when the partition -- elaboration policy is not specified (or is concurrent). -- -- Priority is the task's priority (assumed to be in the -- System.Any_Priority'Range). -- -- Stack_Address is the start address of the stack associated to the task, -- in case it has been preallocated by the compiler; it is equal to -- Null_Address when the stack needs to be allocated by the underlying -- operating system. -- -- Stack_Size is the stack size of the task to create. -- -- Sec_Stack_Address is the pointer to the secondary stack created by the -- compiler. If null, the secondary stack is either allocated by the binder -- or the run-time. -- -- Secondary_Stack_Size is the secondary stack size of the task to create. -- -- Task_Info is the task info associated with the created task, or -- Unspecified_Task_Info if none. -- -- CPU is the task affinity. We pass it as an Integer to avoid an explicit -- dependency from System.Multiprocessors when not needed. Static range -- checks are performed when analyzing the pragma, and dynamic ones are -- performed before setting the affinity at run time. -- -- State is the compiler generated task's procedure body. -- -- Discriminants is a pointer to a limited record whose discriminants are -- those of the task to create. This parameter should be passed as the -- single argument to State. -- -- Elaborated is a pointer to a Boolean that must be set to true on exit -- if the task could be successfully elaborated. -- -- Chain is a linked list of task that needs to be created. On exit, -- Created_Task.Activation_Link will be Chain.T_ID, and Chain.T_ID will be -- Created_Task (the created task will be linked at the front of Chain). -- -- Task_Image is a string created by the compiler that the run time can -- store to ease the debugging and the Ada.Task_Identification facility. -- -- Created_Task is the resulting task. -- -- This procedure can raise Storage_Error if the task creation fails. procedure Create_Restricted_Task_Sequential (Priority : Integer; Stack_Address : System.Address; Stack_Size : System.Parameters.Size_Type; Sec_Stack_Address : System.Secondary_Stack.SS_Stack_Ptr; Sec_Stack_Size : System.Parameters.Size_Type; Task_Info : System.Task_Info.Task_Info_Type; CPU : Integer; State : Task_Procedure_Access; Discriminants : System.Address; Elaborated : Access_Boolean; Task_Image : String; Created_Task : Task_Id); -- Compiler interface only. Do not call from within the RTS. -- This must be called to create a new task, when the sequential partition -- elaboration policy is used. -- -- The parameters are the same as Create_Restricted_Task except there is -- no Chain parameter (for the activation chain), as there is only one -- global activation chain, which is declared in the body of this package. procedure Activate_Restricted_Tasks (Chain_Access : Activation_Chain_Access); -- Compiler interface only. Do not call from within the RTS. -- This must be called by the creator of a chain of one or more new tasks, -- to activate them. The chain is a linked list that up to this point is -- only known to the task that created them, though the individual tasks -- are already in the All_Tasks_List. -- -- The compiler builds the chain in LIFO order (as a stack). Another -- version of this procedure had code to reverse the chain, so as to -- activate the tasks in the order of declaration. This might be nice, but -- it is not needed if priority-based scheduling is supported, since all -- the activated tasks synchronize on the activators lock before they start -- activating and so they should start activating in priority order. -- -- When the partition elaboration policy is sequential, this procedure -- does nothing, tasks will be activated at end of elaboration. procedure Activate_All_Tasks_Sequential; pragma Export (C, Activate_All_Tasks_Sequential, "__gnat_activate_all_tasks"); -- Binder interface only. Do not call from within the RTS. This must be -- called an the end of the elaboration to activate all tasks, in order -- to implement the sequential elaboration policy. procedure Complete_Restricted_Activation; -- Compiler interface only. Do not call from within the RTS. This should be -- called from the task body at the end of the elaboration code for its -- declarative part. Decrement the count of tasks to be activated by the -- activator and wake it up so it can check to see if all tasks have been -- activated. Except for the environment task, which should never call this -- procedure, T.Activator should only be null iff T has completed -- activation. procedure Complete_Restricted_Task; -- Compiler interface only. Do not call from within the RTS. This should be -- called from an implicit at-end handler associated with the task body, -- when it completes. From this point, the current task will become not -- callable. If the current task have not completed activation, this should -- be done now in order to wake up the activator (the environment task). function Restricted_Terminated (T : Task_Id) return Boolean; -- Compiler interface only. Do not call from within the RTS. This is called -- by the compiler to implement the 'Terminated attribute. -- -- source code: -- T1'Terminated -- -- code expansion: -- restricted_terminated (t1._task_id) procedure Finalize_Global_Tasks; -- This is needed to support the compiler interface. It will only be called -- by the Environment task in the binder generated file (by adafinal). -- Instead, it will cause the Environment to block forever, since none of -- the dependent tasks are expected to terminate end System.Tasking.Restricted.Stages;