[thirdparty/gcc.git] / gcc / ada / libgnarl / s-taspri__posix.ads

------------------------------------------------------------------------------
--                                                                          --
--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
--                                                                          --
--               S Y S T E M . T A S K _ P R I M I T I V E S                --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--            Copyright (C) 1991-2017, Florida State University             --
--                     Copyright (C) 1995-2020, AdaCore                     --
--                                                                          --
-- GNAT 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 POSIX-like version of this package

--  Note: this file can only be used for POSIX compliant systems

pragma Polling (Off);
--  Turn off polling, we do not want ATC polling to take place during tasking
--  operations. It causes infinite loops and other problems.

with System.OS_Interface;

package System.Task_Primitives is
   pragma Preelaborate;

   type Lock is limited private;
   --  Should be used for implementation of protected objects

   type RTS_Lock is limited private;
   --  Should be used inside the runtime system. The difference between Lock
   --  and the RTS_Lock is that the latter serves only as a semaphore so that
   --  we do not check for ceiling violations.

   type Suspension_Object is limited private;
   --  Should be used for the implementation of Ada.Synchronous_Task_Control

   type Task_Body_Access is access procedure;
   --  Pointer to the task body's entry point (or possibly a wrapper declared
   --  local to the GNARL).

   type Private_Data is limited private;
   --  Any information that the GNULLI needs maintained on a per-task basis.
   --  A component of this type is guaranteed to be included in the
   --  Ada_Task_Control_Block.

   subtype Task_Address is System.Address;
   Task_Address_Size : constant := Standard'Address_Size;
   --  Type used for task addresses and its size

   Alternate_Stack_Size : constant := System.OS_Interface.Alternate_Stack_Size;
   --  Import value from System.OS_Interface

private

   type RTS_Lock is new System.OS_Interface.pthread_mutex_t;

   type Lock is record
      RW : aliased System.OS_Interface.pthread_rwlock_t;
      WO : aliased RTS_Lock;
   end record;

   type Suspension_Object is record
      State : Boolean;
      pragma Atomic (State);
      --  Boolean that indicates whether the object is open. This field is
      --  marked Atomic to ensure that we can read its value without locking
      --  the access to the Suspension_Object.

      Waiting : Boolean;
      --  Flag showing if there is a task already suspended on this object

      L : aliased RTS_Lock;
      --  Protection for ensuring mutual exclusion on the Suspension_Object

      CV : aliased System.OS_Interface.pthread_cond_t;
      --  Condition variable used to queue threads until condition is signaled
   end record;

   type Private_Data is limited record
      Thread : aliased System.OS_Interface.pthread_t;
      pragma Atomic (Thread);
      --  Thread field may be updated by two different threads of control.
      --  (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
      --  value (thr_self value). We do not want to use lock on those
      --  operations and the only thing we have to make sure is that they are
      --  updated in atomic fashion.

      LWP : aliased System.Address;
      --  The purpose of this field is to provide a better tasking support on
      --  gdb. The order of the two first fields (Thread and LWP) is important.
      --  On targets where lwp is not relevant, this is equivalent to Thread.

      CV : aliased System.OS_Interface.pthread_cond_t;
      --  Should be commented ??? (in all versions of taspri)

      L : aliased RTS_Lock;
      --  Protection for all components is lock L
   end record;

end System.Task_Primitives;
Commit	Line	Data
84481f76 RK	1	------------------------------------------------------------------------------
84481f76 RK	2	-- --
4c173b50	3	-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
84481f76	4	-- --
4c173b50	5	-- S Y S T E M . T A S K _ P R I M I T I V E S --
84481f76	6	-- --
4c173b50	7	-- S p e c --
84481f76	8	-- --
cfc29a96	9	-- Copyright (C) 1991-2017, Florida State University --
4b490c1e	10	-- Copyright (C) 1995-2020, AdaCore --
84481f76	11	-- --
607d0635	12	-- GNAT is free software; you can redistribute it and/or modify it under --
84481f76	13	-- terms of the GNU General Public License as published by the Free Soft- --
607d0635 AC	14	-- ware Foundation; either version 3, or (at your option) any later ver- --
607d0635 AC	15	-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
84481f76	16	-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
607d0635 AC	17	-- or FITNESS FOR A PARTICULAR PURPOSE. --
	18	-- --
	19	-- As a special exception under Section 7 of GPL version 3, you are granted --
	20	-- additional permissions described in the GCC Runtime Library Exception, --
	21	-- version 3.1, as published by the Free Software Foundation. --
	22	-- --
	23	-- You should have received a copy of the GNU General Public License and --
	24	-- a copy of the GCC Runtime Library Exception along with this program; --
	25	-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
	26	-- <http://www.gnu.org/licenses/>. --
84481f76	27	-- --
fbf5a39b AC	28	-- GNARL was developed by the GNARL team at Florida State University. --
fbf5a39b AC	29	-- Extensive contributions were provided by Ada Core Technologies, Inc. --
84481f76 RK	30	-- --
	31	------------------------------------------------------------------------------
	32
b497b460 JR	33	-- This is a POSIX-like version of this package
	34
	35	-- Note: this file can only be used for POSIX compliant systems
84481f76 RK	36
84481f76 RK	37	pragma Polling (Off);
366b8af7 RD	38	-- Turn off polling, we do not want ATC polling to take place during tasking
366b8af7 RD	39	-- operations. It causes infinite loops and other problems.
84481f76 RK	40
84481f76 RK	41	with System.OS_Interface;
84481f76 RK	42
84481f76 RK	43	package System.Task_Primitives is
3b91d88e	44	pragma Preelaborate;
84481f76 RK	45
84481f76 RK	46	type Lock is limited private;
b497b460	47	-- Should be used for implementation of protected objects
84481f76 RK	48
84481f76 RK	49	type RTS_Lock is limited private;
b497b460	50	-- Should be used inside the runtime system. The difference between Lock
b0c5fdda AC	51	-- and the RTS_Lock is that the latter serves only as a semaphore so that
b0c5fdda AC	52	-- we do not check for ceiling violations.
b497b460 JR	53
	54	type Suspension_Object is limited private;
	55	-- Should be used for the implementation of Ada.Synchronous_Task_Control
84481f76 RK	56
84481f76 RK	57	type Task_Body_Access is access procedure;
b497b460 JR	58	-- Pointer to the task body's entry point (or possibly a wrapper declared
b497b460 JR	59	-- local to the GNARL).
84481f76 RK	60
84481f76 RK	61	type Private_Data is limited private;
b497b460 JR	62	-- Any information that the GNULLI needs maintained on a per-task basis.
	63	-- A component of this type is guaranteed to be included in the
	64	-- Ada_Task_Control_Block.
84481f76	65
eb0a4598	66	subtype Task_Address is System.Address;
eb0a4598	67	Task_Address_Size : constant := Standard'Address_Size;
7a5b62b0	68	-- Type used for task addresses and its size
eb0a4598 AC	69
	70	Alternate_Stack_Size : constant := System.OS_Interface.Alternate_Stack_Size;
	71	-- Import value from System.OS_Interface
	72
84481f76 RK	73	private
84481f76 RK	74
c5b4738f AC	75	type RTS_Lock is new System.OS_Interface.pthread_mutex_t;
c5b4738f AC	76
64a63cd5 PO	77	type Lock is record
64a63cd5 PO	78	RW : aliased System.OS_Interface.pthread_rwlock_t;
c5b4738f	79	WO : aliased RTS_Lock;
64a63cd5 PO	80	end record;
64a63cd5 PO	81
b497b460 JR	82	type Suspension_Object is record
	83	State : Boolean;
	84	pragma Atomic (State);
	85	-- Boolean that indicates whether the object is open. This field is
	86	-- marked Atomic to ensure that we can read its value without locking
	87	-- the access to the Suspension_Object.
	88
	89	Waiting : Boolean;
	90	-- Flag showing if there is a task already suspended on this object
	91
c5b4738f	92	L : aliased RTS_Lock;
b497b460 JR	93	-- Protection for ensuring mutual exclusion on the Suspension_Object
	94
	95	CV : aliased System.OS_Interface.pthread_cond_t;
	96	-- Condition variable used to queue threads until condition is signaled
	97	end record;
	98
ddce04b8	99	type Private_Data is limited record
84481f76 RK	100	Thread : aliased System.OS_Interface.pthread_t;
	101	pragma Atomic (Thread);
	102	-- Thread field may be updated by two different threads of control.
b497b460 JR	103	-- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
	104	-- value (thr_self value). We do not want to use lock on those
	105	-- operations and the only thing we have to make sure is that they are
	106	-- updated in atomic fashion.
84481f76 RK	107
	108	LWP : aliased System.Address;
	109	-- The purpose of this field is to provide a better tasking support on
	110	-- gdb. The order of the two first fields (Thread and LWP) is important.
	111	-- On targets where lwp is not relevant, this is equivalent to Thread.
	112
	113	CV : aliased System.OS_Interface.pthread_cond_t;
b497b460	114	-- Should be commented ??? (in all versions of taspri)
84481f76	115
b497b460	116	L : aliased RTS_Lock;
84481f76 RK	117	-- Protection for all components is lock L
	118	end record;
	119
	120	end System.Task_Primitives;