1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- 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 --
9 -- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
11 -- GNARL is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNARL was developed by the GNARL team at Florida State University. --
28 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
30 ------------------------------------------------------------------------------
32 -- This is a simplified version of the System.Tasking.Stages package,
33 -- intended to be used in a restricted run time.
35 -- This package represents the high level tasking interface used by the
36 -- compiler to expand Ada 95 tasking constructs into simpler run time calls
37 -- (aka GNARLI, GNU Ada Run-time Library Interface)
39 -- Note: the compiler generates direct calls to this interface, via Rtsfind.
40 -- Any changes to this interface may require corresponding compiler changes
41 -- in exp_ch9.adb and possibly exp_ch7.adb
43 -- The restricted GNARLI is also composed of System.Protected_Objects and
44 -- System.Protected_Objects.Single_Entry
46 with System
.Task_Info
;
47 with System
.Parameters
;
49 package System
.Tasking
.Restricted
.Stages
is
50 pragma Elaborate_Body
;
52 ---------------------------------
53 -- Compiler Interface (GNARLI) --
54 ---------------------------------
56 -- The compiler will expand in the GNAT tree the following construct:
58 -- task type T (Discr : Integer);
61 -- ...declarations, possibly some controlled...
70 -- task type t (discr : integer);
71 -- tE : aliased boolean := false;
72 -- tZ : size_type := unspecified_size;
74 -- type tV (discr : integer) is limited record
75 -- _task_id : task_id;
76 -- _atcb : aliased system__tasking__ada_task_control_block (0);
79 -- procedure tB (_task : access tV);
81 -- procedure tVIP (_init : in out tV; _master : master_id;
82 -- _chain : in out activation_chain; _task_name : in string;
83 -- discr : integer) is
85 -- _init.discr := discr;
86 -- _init._task_id := null;
87 -- system__tasking__ada_task_control_blockIP (_init._atcb, 0);
88 -- _init._task_id := _init._atcb'unchecked_access;
89 -- create_restricted_task (unspecified_priority, tZ,
90 -- unspecified_task_info, unspecified_cpu,
91 -- task_procedure_access!(tB'address), _init'address,
92 -- tE'unchecked_access, _chain, _task_name, _init._task_id);
96 -- _chain : aliased activation_chain;
97 -- activation_chainIP (_chain);
99 -- procedure tB (_task : access tV) is
100 -- discr : integer renames _task.discr;
102 -- procedure _clean is
104 -- complete_restricted_task;
105 -- finalize_list (F14b);
110 -- ...declarations...
111 -- complete_restricted_activation;
120 -- t1S : constant String := "t1";
121 -- tIP (t1, 3, _chain, t1S, 1);
123 -- activate_restricted_tasks (_chain'unchecked_access);
125 procedure Create_Restricted_Task
127 Stack_Address
: System
.Address
;
128 Size
: System
.Parameters
.Size_Type
;
129 Task_Info
: System
.Task_Info
.Task_Info_Type
;
131 State
: Task_Procedure_Access
;
132 Discriminants
: System
.Address
;
133 Elaborated
: Access_Boolean
;
134 Chain
: in out Activation_Chain
;
136 Created_Task
: Task_Id
);
137 -- Compiler interface only. Do not call from within the RTS.
138 -- This must be called to create a new task.
140 -- Priority is the task's priority (assumed to be in the
141 -- System.Any_Priority'Range)
143 -- Stack_Address is the start address of the stack associated to the task,
144 -- in case it has been preallocated by the compiler; it is equal to
145 -- Null_Address when the stack needs to be allocated by the underlying
148 -- Size is the stack size of the task to create
150 -- Task_Info is the task info associated with the created task, or
151 -- Unspecified_Task_Info if none.
153 -- CPU is the task affinity. We pass it as an Integer to avoid an explicit
154 -- dependency from System.Multiprocessors when not needed. Static range
155 -- checks are performed when analyzing the pragma, and dynamic ones are
156 -- performed before setting the affinity at run time.
158 -- State is the compiler generated task's procedure body
160 -- Discriminants is a pointer to a limited record whose discriminants are
161 -- those of the task to create. This parameter should be passed as the
162 -- single argument to State.
164 -- Elaborated is a pointer to a Boolean that must be set to true on exit
165 -- if the task could be successfully elaborated.
167 -- Chain is a linked list of task that needs to be created. On exit,
168 -- Created_Task.Activation_Link will be Chain.T_ID, and Chain.T_ID will be
169 -- Created_Task (the created task will be linked at the front of Chain).
171 -- Task_Image is a string created by the compiler that the run time can
172 -- store to ease the debugging and the Ada.Task_Identification facility.
174 -- Created_Task is the resulting task.
176 -- This procedure can raise Storage_Error if the task creation fails
178 procedure Activate_Restricted_Tasks
179 (Chain_Access
: Activation_Chain_Access
);
180 -- Compiler interface only. Do not call from within the RTS.
181 -- This must be called by the creator of a chain of one or more new tasks,
182 -- to activate them. The chain is a linked list that up to this point is
183 -- only known to the task that created them, though the individual tasks
184 -- are already in the All_Tasks_List.
186 -- The compiler builds the chain in LIFO order (as a stack). Another
187 -- version of this procedure had code to reverse the chain, so as to
188 -- activate the tasks in the order of declaration. This might be nice, but
189 -- it is not needed if priority-based scheduling is supported, since all
190 -- the activated tasks synchronize on the activators lock before they start
191 -- activating and so they should start activating in priority order.
193 procedure Complete_Restricted_Activation
;
194 -- Compiler interface only. Do not call from within the RTS. This should be
195 -- called from the task body at the end of the elaboration code for its
196 -- declarative part. Decrement the count of tasks to be activated by the
197 -- activator and wake it up so it can check to see if all tasks have been
198 -- activated. Except for the environment task, which should never call this
199 -- procedure, T.Activator should only be null iff T has completed
202 procedure Complete_Restricted_Task
;
203 -- Compiler interface only. Do not call from within the RTS. This should be
204 -- called from an implicit at-end handler associated with the task body,
205 -- when it completes. From this point, the current task will become not
206 -- callable. If the current task have not completed activation, this should
207 -- be done now in order to wake up the activator (the environment task).
209 function Restricted_Terminated
(T
: Task_Id
) return Boolean;
210 -- Compiler interface only. Do not call from within the RTS. This is called
211 -- by the compiler to implement the 'Terminated attribute.
217 -- restricted_terminated (t1._task_id)
219 procedure Finalize_Global_Tasks
;
220 -- This is needed to support the compiler interface; it will only be called
221 -- by the Environment task in the binder generated file (by adafinal).
222 -- Instead, it will cause the Environment to block forever, since none of
223 -- the dependent tasks are expected to terminate
225 end System
.Tasking
.Restricted
.Stages
;