| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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) 1992-2021, 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 -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- 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; |
