gcc/ada/s-taspri-solaris.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                  GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                --
   4 --                                                                          --
   5 --                 S Y S T E M . T A S K _ P R I M I T I V E S              --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2011, Free Software Foundation, Inc.         --
  10 --                                                                          --
  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.                                     --
  17 --                                                                          --
  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.               --
  21 --                                                                          --
  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/>.                                          --
  26 --                                                                          --
  27 -- GNARL was developed by the GNARL team at Florida State University.       --
  28 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is a Solaris version of this package
  33
  34 --  This package provides low-level support for most tasking features
  35
  36 pragma Polling (Off);
  37 --  Turn off polling, we do not want ATC polling to take place during tasking
  38 --  operations. It causes infinite loops and other problems.
  39
  40 with Ada.Unchecked_Conversion;
  41
  42 with System.OS_Interface;
  43
  44 package System.Task_Primitives is
  45    pragma Preelaborate;
  46
  47    type Lock is limited private;
  48    type Lock_Ptr is access all Lock;
  49    --  Should be used for implementation of protected objects
  50
  51    type RTS_Lock is limited private;
  52    type RTS_Lock_Ptr is access all RTS_Lock;
  53    --  Should be used inside the runtime system. The difference between Lock
  54    --  and the RTS_Lock is that the later one serves only as a semaphore so
  55    --  that do not check for ceiling violations.
  56
  57    function To_Lock_Ptr is
  58      new Ada.Unchecked_Conversion (RTS_Lock_Ptr, Lock_Ptr);
  59
  60    type Suspension_Object is limited private;
  61    --  Should be used for the implementation of Ada.Synchronous_Task_Control
  62
  63    type Task_Body_Access is access procedure;
  64    --  Pointer to the task body's entry point (or possibly a wrapper
  65    --  declared local to the GNARL).
  66
  67    type Private_Data is limited private;
  68    --  Any information that the GNULLI needs maintained on a per-task basis.
  69    --  A component of this type is guaranteed to be included in the
  70    --  Ada_Task_Control_Block.
  71
  72    subtype Task_Address is System.Address;
  73    --  In some versions of Task_Primitives, notably for VMS, Task_Address is
  74    --  the short version of address defined in System.Aux_DEC. To avoid
  75    --  dragging Aux_DEC into tasking packages a tasking specific subtype is
  76    --  defined here.
  77
  78    Task_Address_Size : constant := Standard'Address_Size;
  79    --  The size of Task_Address
  80
  81    Alternate_Stack_Size : constant := 0;
  82    --  No alternate signal stack is used on this platform
  83
  84 private
  85
  86    type Private_Task_Serial_Number is mod 2 ** 64;
  87    --  Used to give each task a unique serial number
  88
  89    type Base_Lock is new System.OS_Interface.mutex_t;
  90
  91    type Owner_Int is new Integer;
  92    for Owner_Int'Alignment use Standard'Maximum_Alignment;
  93
  94    type Owner_ID is access all Owner_Int;
  95
  96    function To_Owner_ID is
  97      new Ada.Unchecked_Conversion (System.Address, Owner_ID);
  98
  99    type Lock is record
 100       L              : aliased Base_Lock;
 101       Ceiling        : System.Any_Priority := System.Any_Priority'First;
 102       Saved_Priority : System.Any_Priority :=  System.Any_Priority'First;
 103       Owner          : Owner_ID;
 104       Next           : Lock_Ptr;
 105       Level          : Private_Task_Serial_Number := 0;
 106       Buddy          : Owner_ID;
 107       Frozen         : Boolean := False;
 108    end record;
 109
 110    type RTS_Lock is new Lock;
 111
 112    type Suspension_Object is record
 113       State : Boolean;
 114       pragma Atomic (State);
 115       --  Boolean that indicates whether the object is open. This field is
 116       --  marked Atomic to ensure that we can read its value without locking
 117       --  the access to the Suspension_Object.
 118
 119       Waiting : Boolean;
 120       --  Flag showing if there is a task already suspended on this object
 121
 122       L : aliased System.OS_Interface.mutex_t;
 123       --  Protection for ensuring mutual exclusion on the Suspension_Object
 124
 125       CV : aliased System.OS_Interface.cond_t;
 126       --  Condition variable used to queue threads until condition is signaled
 127    end record;
 128
 129    --  Note that task support on gdb relies on the fact that the first two
 130    --  fields of Private_Data are Thread and LWP.
 131
 132    type Private_Data is record
 133       Thread : aliased System.OS_Interface.thread_t;
 134       pragma Atomic (Thread);
 135       --  Thread field may be updated by two different threads of control.
 136       --  (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
 137       --  value (thr_self value). We do not want to use lock on those
 138       --  operations and the only thing we have to make sure is that they are
 139       --  updated in atomic fashion.
 140
 141       LWP : System.OS_Interface.lwpid_t;
 142       --  The LWP id of the thread. Set by self in Enter_Task
 143
 144       CV : aliased System.OS_Interface.cond_t;
 145       L  : aliased RTS_Lock;
 146       --  Protection for all components is lock L
 147
 148       Active_Priority : System.Any_Priority := System.Any_Priority'First;
 149       --  Simulated active priority, used iff Priority_Ceiling_Support is True
 150
 151       Locking : Lock_Ptr;
 152       Locks   : Lock_Ptr;
 153       Wakeups : Natural := 0;
 154    end record;
 155
 156 end System.Task_Primitives;