261 lines
12 KiB
Ada
261 lines
12 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
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-- --
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-- 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 --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
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-- --
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-- GNARL is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNARL was developed by the GNARL team at Florida State University. --
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-- Extensive contributions were provided by Ada Core Technologies, Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This is a simplified version of the System.Tasking.Stages package,
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-- intended to be used in a restricted run time.
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-- This package represents the high level tasking interface used by the
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-- compiler to expand Ada 95 tasking constructs into simpler run time calls
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-- (aka GNARLI, GNU Ada Run-time Library Interface)
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-- Note: the compiler generates direct calls to this interface, via Rtsfind.
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-- Any changes to this interface may require corresponding compiler changes
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-- in exp_ch9.adb and possibly exp_ch7.adb
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-- The restricted GNARLI is also composed of System.Protected_Objects and
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-- System.Protected_Objects.Single_Entry
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with System.Task_Info;
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with System.Parameters;
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package System.Tasking.Restricted.Stages is
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pragma Elaborate_Body;
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---------------------------------
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-- Compiler Interface (GNARLI) --
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---------------------------------
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-- The compiler will expand in the GNAT tree the following construct:
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-- task type T (Discr : Integer);
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-- task body T is
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-- ...declarations, possibly some controlled...
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-- begin
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-- ...B...;
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-- end T;
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-- T1 : T (1);
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-- as follows:
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-- task type t (discr : integer);
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-- tE : aliased boolean := false;
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-- tZ : size_type := unspecified_size;
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-- type tV (discr : integer) is limited record
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-- _task_id : task_id;
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-- _atcb : aliased system__tasking__ada_task_control_block (0);
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-- end record;
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-- procedure tB (_task : access tV);
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-- freeze tV [
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-- procedure tVIP (_init : in out tV; _master : master_id;
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-- _chain : in out activation_chain; _task_name : in string;
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-- discr : integer) is
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-- begin
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-- _init.discr := discr;
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-- _init._task_id := null;
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-- system__tasking__ada_task_control_blockIP (_init._atcb, 0);
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-- _init._task_id := _init._atcb'unchecked_access;
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-- create_restricted_task (unspecified_priority, tZ,
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-- unspecified_task_info, unspecified_cpu,
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-- task_procedure_access!(tB'address), _init'address,
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-- tE'unchecked_access, _task_name, _init._task_id);
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-- return;
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-- end tVIP;
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-- _chain : aliased activation_chain;
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-- activation_chainIP (_chain);
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-- procedure tB (_task : access tV) is
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-- discr : integer renames _task.discr;
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-- procedure _clean is
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-- begin
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-- complete_restricted_task;
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-- finalize_list (F14b);
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-- return;
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-- end _clean;
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-- begin
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-- ...declarations...
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-- complete_restricted_activation;
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-- ...B...;
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-- return;
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-- at end
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-- _clean;
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-- end tB;
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-- tE := true;
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-- t1 : t (1);
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-- t1S : constant String := "t1";
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-- tIP (t1, 3, _chain, t1S, 1);
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Partition_Elaboration_Policy : Character := 'C';
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pragma Export (C, Partition_Elaboration_Policy,
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"__gnat_partition_elaboration_policy");
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-- Partition elaboration policy. Value can be either 'C' for concurrent,
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-- which is the default or 'S' for sequential. This value can be modified
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-- by the binder generated code, before calling elaboration code.
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procedure Create_Restricted_Task
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(Priority : Integer;
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Stack_Address : System.Address;
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Size : System.Parameters.Size_Type;
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Task_Info : System.Task_Info.Task_Info_Type;
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CPU : Integer;
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State : Task_Procedure_Access;
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Discriminants : System.Address;
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Elaborated : Access_Boolean;
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Chain : in out Activation_Chain;
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Task_Image : String;
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Created_Task : Task_Id);
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-- Compiler interface only. Do not call from within the RTS.
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-- This must be called to create a new task, when the partition
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-- elaboration policy is not specified (or is concurrent).
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--
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-- Priority is the task's priority (assumed to be in the
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-- System.Any_Priority'Range)
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--
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-- Stack_Address is the start address of the stack associated to the task,
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-- in case it has been preallocated by the compiler; it is equal to
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-- Null_Address when the stack needs to be allocated by the underlying
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-- operating system.
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--
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-- Size is the stack size of the task to create
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--
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-- Task_Info is the task info associated with the created task, or
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-- Unspecified_Task_Info if none.
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--
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-- CPU is the task affinity. We pass it as an Integer to avoid an explicit
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-- dependency from System.Multiprocessors when not needed. Static range
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-- checks are performed when analyzing the pragma, and dynamic ones are
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-- performed before setting the affinity at run time.
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--
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-- State is the compiler generated task's procedure body
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--
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-- Discriminants is a pointer to a limited record whose discriminants are
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-- those of the task to create. This parameter should be passed as the
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-- single argument to State.
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--
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-- Elaborated is a pointer to a Boolean that must be set to true on exit
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-- if the task could be successfully elaborated.
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--
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-- Chain is a linked list of task that needs to be created. On exit,
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-- Created_Task.Activation_Link will be Chain.T_ID, and Chain.T_ID will be
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-- Created_Task (the created task will be linked at the front of Chain).
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--
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-- Task_Image is a string created by the compiler that the run time can
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-- store to ease the debugging and the Ada.Task_Identification facility.
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--
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-- Created_Task is the resulting task.
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--
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-- This procedure can raise Storage_Error if the task creation fails
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procedure Create_Restricted_Task_Sequential
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(Priority : Integer;
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Stack_Address : System.Address;
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Size : System.Parameters.Size_Type;
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Task_Info : System.Task_Info.Task_Info_Type;
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CPU : Integer;
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State : Task_Procedure_Access;
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Discriminants : System.Address;
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Elaborated : Access_Boolean;
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Task_Image : String;
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Created_Task : Task_Id);
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-- Compiler interface only. Do not call from within the RTS.
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-- This must be called to create a new task, when the sequential partition
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-- elaboration policy is used.
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--
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-- The parameters are the same as Create_Restricted_Task except there is
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-- no Chain parameter (for the activation chain), as there is only one
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-- global activation chain, which is declared in the body of this package.
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procedure Activate_Restricted_Tasks
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(Chain_Access : Activation_Chain_Access);
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-- Compiler interface only. Do not call from within the RTS.
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-- This must be called by the creator of a chain of one or more new tasks,
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-- to activate them. The chain is a linked list that up to this point is
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-- only known to the task that created them, though the individual tasks
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-- are already in the All_Tasks_List.
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--
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-- The compiler builds the chain in LIFO order (as a stack). Another
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-- version of this procedure had code to reverse the chain, so as to
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-- activate the tasks in the order of declaration. This might be nice, but
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-- it is not needed if priority-based scheduling is supported, since all
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-- the activated tasks synchronize on the activators lock before they start
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-- activating and so they should start activating in priority order.
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--
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-- When the partition elaboration policy is sequential, this procedure
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-- does nothing, tasks will be activated at end of elaboration.
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procedure Activate_All_Tasks_Sequential;
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pragma Export (C, Activate_All_Tasks_Sequential,
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"__gnat_activate_all_tasks");
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-- Binder interface only. Do not call from within the RTS. This must be
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-- called an the end of the elaboration to activate all tasks, in order
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-- to implement the sequential elaboration policy.
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procedure Complete_Restricted_Activation;
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-- Compiler interface only. Do not call from within the RTS. This should be
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-- called from the task body at the end of the elaboration code for its
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-- declarative part. Decrement the count of tasks to be activated by the
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-- activator and wake it up so it can check to see if all tasks have been
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-- activated. Except for the environment task, which should never call this
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-- procedure, T.Activator should only be null iff T has completed
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-- activation.
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procedure Complete_Restricted_Task;
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-- Compiler interface only. Do not call from within the RTS. This should be
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-- called from an implicit at-end handler associated with the task body,
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-- when it completes. From this point, the current task will become not
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-- callable. If the current task have not completed activation, this should
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-- be done now in order to wake up the activator (the environment task).
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function Restricted_Terminated (T : Task_Id) return Boolean;
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-- Compiler interface only. Do not call from within the RTS. This is called
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-- by the compiler to implement the 'Terminated attribute.
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--
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-- source code:
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-- T1'Terminated
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--
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-- code expansion:
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-- restricted_terminated (t1._task_id)
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procedure Finalize_Global_Tasks;
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-- This is needed to support the compiler interface. It will only be called
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-- by the Environment task in the binder generated file (by adafinal).
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-- Instead, it will cause the Environment to block forever, since none of
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-- the dependent tasks are expected to terminate
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end System.Tasking.Restricted.Stages;
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