diff options
Diffstat (limited to 'gcc/ada/s-tassta.ads')
| -rw-r--r-- | gcc/ada/s-tassta.ads | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/gcc/ada/s-tassta.ads b/gcc/ada/s-tassta.ads new file mode 100644 index 000000000..6b8c7d7df --- /dev/null +++ b/gcc/ada/s-tassta.ads @@ -0,0 +1,310 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- +-- -- +-- S Y S T E M . T A S K I N G . S T A G E S -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 1992-2010, 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 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: Only the compiler is allowed to use this interface, by generating +-- direct calls to it, via Rtsfind. + +-- Any changes to this interface may require corresponding compiler changes +-- in exp_ch9.adb and possibly exp_ch7.adb + +with System.Task_Info; +with System.Parameters; + +with Ada.Real_Time; + +package System.Tasking.Stages is + pragma Elaborate_Body; + + -- 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: + + -- enter_master.all; + + -- _chain : aliased activation_chain; + -- activation_chainIP (_chain); + + -- 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; + -- end record; + -- procedure tB (_task : access tV); + -- freeze tV [ + -- procedure tVIP (_init : in out tV; _master : master_id; + -- _chain : in out activation_chain; _task_id : in task_image_type; + -- discr : integer) is + -- begin + -- _init.discr := discr; + -- _init._task_id := null; + -- create_task (unspecified_priority, tZ, + -- unspecified_task_info, unspecified_cpu, + -- ada__real_time__time_span_zero, 0, _master, + -- task_procedure_access!(tB'address), _init'address, + -- tE'unchecked_access, _chain, _task_id, _init._task_id); + -- return; + -- end tVIP; + -- ] + + -- procedure tB (_task : access tV) is + -- discr : integer renames _task.discr; + + -- procedure _clean is + -- begin + -- abort_defer.all; + -- complete_task; + -- finalize_list (F14b); + -- abort_undefer.all; + -- return; + -- end _clean; + -- begin + -- abort_undefer.all; + -- ...declarations... + -- complete_activation; + -- ...B...; + -- return; + -- at end + -- _clean; + -- end tB; + + -- tE := true; + -- t1 : t (1); + -- _master : constant master_id := current_master.all; + -- t1S : task_image_type := new string'"t1"; + -- task_image_typeIP (t1, _master, _chain, t1S, 1); + + -- activate_tasks (_chain'unchecked_access); + + procedure Abort_Tasks (Tasks : Task_List); + -- Compiler interface only. Do not call from within the RTS. Initiate + -- abort, however, the actual abort is done by abortee by means of + -- Abort_Handler and Abort_Undefer + -- + -- source code: + -- Abort T1, T2; + -- code expansion: + -- abort_tasks (task_list'(t1._task_id, t2._task_id)); + + procedure Activate_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. + -- ??? Actually, the body of this package DOES reverse the chain, so I + -- don't understand the above comment. + + procedure Complete_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_Master; + -- Compiler interface only. Do not call from within the RTS. This must + -- be called on exit from any master where Enter_Master was called. + -- Assume abort is deferred at this point. + + procedure Complete_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). + + procedure Create_Task + (Priority : Integer; + Size : System.Parameters.Size_Type; + Task_Info : System.Task_Info.Task_Info_Type; + CPU : Integer; + Relative_Deadline : Ada.Real_Time.Time_Span; + Num_Entries : Task_Entry_Index; + Master : Master_Level; + State : Task_Procedure_Access; + Discriminants : System.Address; + Elaborated : Access_Boolean; + Chain : in out Activation_Chain; + Task_Image : String; + Created_Task : out Task_Id; + Build_Entry_Names : Boolean); + -- Compiler interface only. Do not call from within the RTS. + -- This must be called to create a new task. + -- + -- Priority is the task's priority (assumed to be in range of type + -- System.Any_Priority) + -- Size is the 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. Passed as an Integer because the undefined + -- value is not in the range of CPU_Range. Static range checks are + -- performed when analyzing the pragma, and dynamic ones are performed + -- before setting the affinity at run time. + -- Relative_Deadline is the relative deadline associated with the created + -- task by means of a pragma Relative_Deadline, or 0.0 if none. + -- 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 (e.g 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. + -- Build_Entry_Names is a flag which controls the allocation of the data + -- structure which stores all entry names. + -- + -- This procedure can raise Storage_Error if the task creation failed. + + function Current_Master return Master_Level; + -- Compiler interface only. + -- This is called to obtain the current master nesting level. + + procedure Enter_Master; + -- Compiler interface only. Do not call from within the RTS. + -- This must be called on entry to any "master" where a task, + -- or access type designating objects containing tasks, may be + -- declared. + + procedure Expunge_Unactivated_Tasks (Chain : in out Activation_Chain); + -- Compiler interface only. Do not call from within the RTS. + -- This must be called by the compiler-generated code for an allocator if + -- the allocated object contains tasks, if the allocator exits without + -- calling Activate_Tasks for a given activation chains, as can happen if + -- an exception occurs during initialization of the object. + -- + -- This should be called ONLY for tasks created via an allocator. Recovery + -- of storage for unactivated local task declarations is done by + -- Complete_Master and Complete_Task. + -- + -- We remove each task from Chain and All_Tasks_List before we free the + -- storage of its ATCB. + -- + -- In other places where we recover the storage of unactivated tasks, we + -- need to clean out the entry queues, but here that should not be + -- necessary, since these tasks should not have been visible to any other + -- tasks, and so no task should be able to queue a call on their entries. + -- + -- Just in case somebody misuses this subprogram, there is a check to + -- verify this condition. + + procedure Finalize_Global_Tasks; + -- This should be called to complete the execution of the environment task + -- and shut down the tasking runtime system. It is the equivalent of + -- Complete_Task, but for the environment task. + -- + -- The environment task must first call Complete_Master, to wait for user + -- tasks that depend on library-level packages to terminate. It then calls + -- Abort_Dependents to abort the "independent" library-level server tasks + -- that are created implicitly by the RTS packages (signal and timer server + -- tasks), and then waits for them to terminate. Then, it calls + -- Vulnerable_Complete_Task. + -- + -- It currently also executes the global finalization list, and then resets + -- the "soft links". + + procedure Free_Task (T : Task_Id); + -- Recover all runtime system storage associated with the task T, but only + -- if T has terminated. Do nothing in the other case. It is called from + -- Unchecked_Deallocation, for objects that are or contain tasks. + + procedure Move_Activation_Chain + (From, To : Activation_Chain_Access; + New_Master : Master_ID); + -- Compiler interface only. Do not call from within the RTS. + -- Move all tasks on From list to To list, and change their Master_of_Task + -- to be New_Master. This is used to implement build-in-place function + -- returns. Tasks that are part of the return object are initially placed + -- on an activation chain local to the return statement, and their master + -- is the return statement, in case the return statement is left + -- prematurely (due to raising an exception, being aborted, or a goto or + -- exit statement). Once the return statement has completed successfully, + -- Move_Activation_Chain is called to move them to the caller's activation + -- chain, and change their master to the one passed in by the caller. If + -- that doesn't happen, they will never be activated, and will become + -- terminated on leaving the return statement. + + procedure Set_Entry_Name + (T : Task_Id; + Pos : Task_Entry_Index; + Val : String_Access); + -- This is called by the compiler to map a string which denotes an entry + -- name to a task entry index. + + function Terminated (T : Task_Id) return Boolean; + -- This is called by the compiler to implement the 'Terminated attribute. + -- Though is not required to be so by the ARM, we choose to synchronize + -- with the task's ATCB, so that this is more useful for polling the state + -- of a task, and so that it becomes an abort completion point for the + -- calling task (via Undefer_Abort). + -- + -- source code: + -- T1'Terminated + -- + -- code expansion: + -- terminated (t1._task_id) + + procedure Terminate_Task (Self_ID : Task_Id); + -- Terminate the calling task. + -- This should only be called by the Task_Wrapper procedure, and to + -- deallocate storage associate with foreign tasks. + +end System.Tasking.Stages; |