gcc/ada/s-taprop-mingw.adb

   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 . O P E R A T I O N S    --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2008, 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 2,  or (at your option) any later ver- --
  14 -- sion. GNARL 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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNARL was developed by the GNARL team at Florida State University.       --
  30 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This is a NT (native) version of this package
  35
  36 --  This package contains all the GNULL primitives that interface directly with
  37 --  the underlying OS.
  38
  39 pragma Polling (Off);
  40 --  Turn off polling, we do not want ATC polling to take place during tasking
  41 --  operations. It causes infinite loops and other problems.
  42
  43 with Ada.Unchecked_Deallocation;
  44
  45 with Interfaces.C;
  46 with Interfaces.C.Strings;
  47
  48 with System.Tasking.Debug;
  49 with System.OS_Primitives;
  50 with System.Task_Info;
  51 with System.Interrupt_Management;
  52 with System.Win32.Ext;
  53
  54 with System.Soft_Links;
  55 --  We use System.Soft_Links instead of System.Tasking.Initialization because
  56 --  the later is a higher level package that we shouldn't depend on. For
  57 --  example when using the restricted run time, it is replaced by
  58 --  System.Tasking.Restricted.Stages.
  59
  60 package body System.Task_Primitives.Operations is
  61
  62    package SSL renames System.Soft_Links;
  63
  64    use System.Tasking.Debug;
  65    use System.Tasking;
  66    use Interfaces.C;
  67    use Interfaces.C.Strings;
  68    use System.OS_Interface;
  69    use System.Parameters;
  70    use System.OS_Primitives;
  71    use System.Task_Info;
  72    use System.Win32;
  73    use System.Win32.Ext;
  74
  75    pragma Link_With ("-Xlinker --stack=0x200000,0x1000");
  76    --  Change the default stack size (2 MB) for tasking programs on Windows.
  77    --  This allows about 1000 tasks running at the same time. Note that
  78    --  we set the stack size for non tasking programs on System unit.
  79    --  Also note that under Windows XP, we use a Windows XP extension to
  80    --  specify the stack size on a per task basis, as done under other OSes.
  81
  82    ---------------------
  83    -- Local Functions --
  84    ---------------------
  85
  86    procedure InitializeCriticalSection (pCriticalSection : access RTS_Lock);
  87    procedure InitializeCriticalSection
  88      (pCriticalSection : access CRITICAL_SECTION);
  89    pragma Import
  90      (Stdcall, InitializeCriticalSection, "InitializeCriticalSection");
  91
  92    procedure EnterCriticalSection (pCriticalSection : access RTS_Lock);
  93    procedure EnterCriticalSection
  94      (pCriticalSection : access CRITICAL_SECTION);
  95    pragma Import (Stdcall, EnterCriticalSection, "EnterCriticalSection");
  96
  97    procedure LeaveCriticalSection (pCriticalSection : access RTS_Lock);
  98    procedure LeaveCriticalSection (pCriticalSection : access CRITICAL_SECTION);
  99    pragma Import (Stdcall, LeaveCriticalSection, "LeaveCriticalSection");
 100
 101    procedure DeleteCriticalSection (pCriticalSection : access RTS_Lock);
 102    procedure DeleteCriticalSection
 103      (pCriticalSection : access CRITICAL_SECTION);
 104    pragma Import (Stdcall, DeleteCriticalSection, "DeleteCriticalSection");
 105
 106    ----------------
 107    -- Local Data --
 108    ----------------
 109
 110    Environment_Task_Id : Task_Id;
 111    --  A variable to hold Task_Id for the environment task
 112
 113    Single_RTS_Lock : aliased RTS_Lock;
 114    --  This is a lock to allow only one thread of control in the RTS at
 115    --  a time; it is used to execute in mutual exclusion from all other tasks.
 116    --  Used mainly in Single_Lock mode, but also to protect All_Tasks_List
 117
 118    Time_Slice_Val : Integer;
 119    pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
 120
 121    Dispatching_Policy : Character;
 122    pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
 123
 124    function Get_Policy (Prio : System.Any_Priority) return Character;
 125    pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
 126    --  Get priority specific dispatching policy
 127
 128    Foreign_Task_Elaborated : aliased Boolean := True;
 129    --  Used to identified fake tasks (i.e., non-Ada Threads)
 130
 131    Annex_D : Boolean := False;
 132    --  Set to True if running with Annex-D semantics
 133
 134    ------------------------------------
 135    -- The thread local storage index --
 136    ------------------------------------
 137
 138    TlsIndex : DWORD;
 139    pragma Export (Ada, TlsIndex);
 140    --  To ensure that this variable won't be local to this package, since
 141    --  in some cases, inlining forces this variable to be global anyway.
 142
 143    --------------------
 144    -- Local Packages --
 145    --------------------
 146
 147    package Specific is
 148
 149       function Is_Valid_Task return Boolean;
 150       pragma Inline (Is_Valid_Task);
 151       --  Does executing thread have a TCB?
 152
 153       procedure Set (Self_Id : Task_Id);
 154       pragma Inline (Set);
 155       --  Set the self id for the current task
 156
 157    end Specific;
 158
 159    package body Specific is
 160
 161       function Is_Valid_Task return Boolean is
 162       begin
 163          return TlsGetValue (TlsIndex) /= System.Null_Address;
 164       end Is_Valid_Task;
 165
 166       procedure Set (Self_Id : Task_Id) is
 167          Succeeded : BOOL;
 168       begin
 169          Succeeded := TlsSetValue (TlsIndex, To_Address (Self_Id));
 170          pragma Assert (Succeeded = Win32.TRUE);
 171       end Set;
 172
 173    end Specific;
 174
 175    ---------------------------------
 176    -- Support for foreign threads --
 177    ---------------------------------
 178
 179    function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
 180    --  Allocate and Initialize a new ATCB for the current Thread
 181
 182    function Register_Foreign_Thread
 183      (Thread : Thread_Id) return Task_Id is separate;
 184
 185    ----------------------------------
 186    -- Condition Variable Functions --
 187    ----------------------------------
 188
 189    procedure Initialize_Cond (Cond : not null access Condition_Variable);
 190    --  Initialize given condition variable Cond
 191
 192    procedure Finalize_Cond (Cond : not null access Condition_Variable);
 193    --  Finalize given condition variable Cond
 194
 195    procedure Cond_Signal (Cond : not null access Condition_Variable);
 196    --  Signal condition variable Cond
 197
 198    procedure Cond_Wait
 199      (Cond : not null access Condition_Variable;
 200       L    : not null access RTS_Lock);
 201    --  Wait on conditional variable Cond, using lock L
 202
 203    procedure Cond_Timed_Wait
 204      (Cond      : not null access Condition_Variable;
 205       L         : not null access RTS_Lock;
 206       Rel_Time  : Duration;
 207       Timed_Out : out Boolean;
 208       Status    : out Integer);
 209    --  Do timed wait on condition variable Cond using lock L. The duration
 210    --  of the timed wait is given by Rel_Time. When the condition is
 211    --  signalled, Timed_Out shows whether or not a time out occurred.
 212    --  Status is only valid if Timed_Out is False, in which case it
 213    --  shows whether Cond_Timed_Wait completed successfully.
 214
 215    ---------------------
 216    -- Initialize_Cond --
 217    ---------------------
 218
 219    procedure Initialize_Cond (Cond : not null access Condition_Variable) is
 220       hEvent : HANDLE;
 221    begin
 222       hEvent := CreateEvent (null, Win32.TRUE, Win32.FALSE, Null_Ptr);
 223       pragma Assert (hEvent /= 0);
 224       Cond.all := Condition_Variable (hEvent);
 225    end Initialize_Cond;
 226
 227    -------------------
 228    -- Finalize_Cond --
 229    -------------------
 230
 231    --  No such problem here, DosCloseEventSem has been derived.
 232    --  What does such refer to in above comment???
 233
 234    procedure Finalize_Cond (Cond : not null access Condition_Variable) is
 235       Result : BOOL;
 236    begin
 237       Result := CloseHandle (HANDLE (Cond.all));
 238       pragma Assert (Result = Win32.TRUE);
 239    end Finalize_Cond;
 240
 241    -----------------
 242    -- Cond_Signal --
 243    -----------------
 244
 245    procedure Cond_Signal (Cond : not null access Condition_Variable) is
 246       Result : BOOL;
 247    begin
 248       Result := SetEvent (HANDLE (Cond.all));
 249       pragma Assert (Result = Win32.TRUE);
 250    end Cond_Signal;
 251
 252    ---------------
 253    -- Cond_Wait --
 254    ---------------
 255
 256    --  Pre-condition: Cond is posted
 257    --                 L is locked.
 258
 259    --  Post-condition: Cond is posted
 260    --                  L is locked.
 261
 262    procedure Cond_Wait
 263      (Cond : not null access Condition_Variable;
 264       L    : not null access RTS_Lock)
 265    is
 266       Result      : DWORD;
 267       Result_Bool : BOOL;
 268
 269    begin
 270       --  Must reset Cond BEFORE L is unlocked
 271
 272       Result_Bool := ResetEvent (HANDLE (Cond.all));
 273       pragma Assert (Result_Bool = Win32.TRUE);
 274       Unlock (L, Global_Lock => True);
 275
 276       --  No problem if we are interrupted here: if the condition is signaled,
 277       --  WaitForSingleObject will simply not block
 278
 279       Result := WaitForSingleObject (HANDLE (Cond.all), Wait_Infinite);
 280       pragma Assert (Result = 0);
 281
 282       Write_Lock (L, Global_Lock => True);
 283    end Cond_Wait;
 284
 285    ---------------------
 286    -- Cond_Timed_Wait --
 287    ---------------------
 288
 289    --  Pre-condition: Cond is posted
 290    --                 L is locked.
 291
 292    --  Post-condition: Cond is posted
 293    --                  L is locked.
 294
 295    procedure Cond_Timed_Wait
 296      (Cond      : not null access Condition_Variable;
 297       L         : not null access RTS_Lock;
 298       Rel_Time  : Duration;
 299       Timed_Out : out Boolean;
 300       Status    : out Integer)
 301    is
 302       Time_Out_Max : constant DWORD := 16#FFFF0000#;
 303       --  NT 4 can't handle excessive timeout values (e.g. DWORD'Last - 1)
 304
 305       Time_Out    : DWORD;
 306       Result      : BOOL;
 307       Wait_Result : DWORD;
 308
 309    begin
 310       --  Must reset Cond BEFORE L is unlocked
 311
 312       Result := ResetEvent (HANDLE (Cond.all));
 313       pragma Assert (Result = Win32.TRUE);
 314       Unlock (L, Global_Lock => True);
 315
 316       --  No problem if we are interrupted here: if the condition is signaled,
 317       --  WaitForSingleObject will simply not block
 318
 319       if Rel_Time <= 0.0 then
 320          Timed_Out := True;
 321          Wait_Result := 0;
 322
 323       else
 324          if Rel_Time >= Duration (Time_Out_Max) / 1000 then
 325             Time_Out := Time_Out_Max;
 326          else
 327             Time_Out := DWORD (Rel_Time * 1000);
 328          end if;
 329
 330          Wait_Result := WaitForSingleObject (HANDLE (Cond.all), Time_Out);
 331
 332          if Wait_Result = WAIT_TIMEOUT then
 333             Timed_Out := True;
 334             Wait_Result := 0;
 335          else
 336             Timed_Out := False;
 337          end if;
 338       end if;
 339
 340       Write_Lock (L, Global_Lock => True);
 341
 342       --  Ensure post-condition
 343
 344       if Timed_Out then
 345          Result := SetEvent (HANDLE (Cond.all));
 346          pragma Assert (Result = Win32.TRUE);
 347       end if;
 348
 349       Status := Integer (Wait_Result);
 350    end Cond_Timed_Wait;
 351
 352    ------------------
 353    -- Stack_Guard  --
 354    ------------------
 355
 356    --  The underlying thread system sets a guard page at the bottom of a thread
 357    --  stack, so nothing is needed.
 358    --  ??? Check the comment above
 359
 360    procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
 361       pragma Unreferenced (T, On);
 362    begin
 363       null;
 364    end Stack_Guard;
 365
 366    --------------------
 367    -- Get_Thread_Id  --
 368    --------------------
 369
 370    function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
 371    begin
 372       return T.Common.LL.Thread;
 373    end Get_Thread_Id;
 374
 375    ----------
 376    -- Self --
 377    ----------
 378
 379    function Self return Task_Id is
 380       Self_Id : constant Task_Id := To_Task_Id (TlsGetValue (TlsIndex));
 381    begin
 382       if Self_Id = null then
 383          return Register_Foreign_Thread (GetCurrentThread);
 384       else
 385          return Self_Id;
 386       end if;
 387    end Self;
 388
 389    ---------------------
 390    -- Initialize_Lock --
 391    ---------------------
 392
 393    --  Note: mutexes and cond_variables needed per-task basis are initialized
 394    --  in Initialize_TCB and the Storage_Error is handled. Other mutexes (such
 395    --  as RTS_Lock, Memory_Lock...) used in the RTS is initialized before any
 396    --  status change of RTS. Therefore raising Storage_Error in the following
 397    --  routines should be able to be handled safely.
 398
 399    procedure Initialize_Lock
 400      (Prio : System.Any_Priority;
 401       L    : not null access Lock)
 402    is
 403    begin
 404       InitializeCriticalSection (L.Mutex'Access);
 405       L.Owner_Priority := 0;
 406       L.Priority := Prio;
 407    end Initialize_Lock;
 408
 409    procedure Initialize_Lock
 410      (L : not null access RTS_Lock; Level : Lock_Level)
 411    is
 412       pragma Unreferenced (Level);
 413    begin
 414       InitializeCriticalSection (L);
 415    end Initialize_Lock;
 416
 417    -------------------
 418    -- Finalize_Lock --
 419    -------------------
 420
 421    procedure Finalize_Lock (L : not null access Lock) is
 422    begin
 423       DeleteCriticalSection (L.Mutex'Access);
 424    end Finalize_Lock;
 425
 426    procedure Finalize_Lock (L : not null access RTS_Lock) is
 427    begin
 428       DeleteCriticalSection (L);
 429    end Finalize_Lock;
 430
 431    ----------------
 432    -- Write_Lock --
 433    ----------------
 434
 435    procedure Write_Lock
 436      (L : not null access Lock; Ceiling_Violation : out Boolean) is
 437    begin
 438       L.Owner_Priority := Get_Priority (Self);
 439
 440       if L.Priority < L.Owner_Priority then
 441          Ceiling_Violation := True;
 442          return;
 443       end if;
 444
 445       EnterCriticalSection (L.Mutex'Access);
 446
 447       Ceiling_Violation := False;
 448    end Write_Lock;
 449
 450    procedure Write_Lock
 451      (L           : not null access RTS_Lock;
 452       Global_Lock : Boolean := False)
 453    is
 454    begin
 455       if not Single_Lock or else Global_Lock then
 456          EnterCriticalSection (L);
 457       end if;
 458    end Write_Lock;
 459
 460    procedure Write_Lock (T : Task_Id) is
 461    begin
 462       if not Single_Lock then
 463          EnterCriticalSection (T.Common.LL.L'Access);
 464       end if;
 465    end Write_Lock;
 466
 467    ---------------
 468    -- Read_Lock --
 469    ---------------
 470
 471    procedure Read_Lock
 472      (L : not null access Lock; Ceiling_Violation : out Boolean) is
 473    begin
 474       Write_Lock (L, Ceiling_Violation);
 475    end Read_Lock;
 476
 477    ------------
 478    -- Unlock --
 479    ------------
 480
 481    procedure Unlock (L : not null access Lock) is
 482    begin
 483       LeaveCriticalSection (L.Mutex'Access);
 484    end Unlock;
 485
 486    procedure Unlock
 487      (L : not null access RTS_Lock; Global_Lock : Boolean := False) is
 488    begin
 489       if not Single_Lock or else Global_Lock then
 490          LeaveCriticalSection (L);
 491       end if;
 492    end Unlock;
 493
 494    procedure Unlock (T : Task_Id) is
 495    begin
 496       if not Single_Lock then
 497          LeaveCriticalSection (T.Common.LL.L'Access);
 498       end if;
 499    end Unlock;
 500
 501    -----------------
 502    -- Set_Ceiling --
 503    -----------------
 504
 505    --  Dynamic priority ceilings are not supported by the underlying system
 506
 507    procedure Set_Ceiling
 508      (L    : not null access Lock;
 509       Prio : System.Any_Priority)
 510    is
 511       pragma Unreferenced (L, Prio);
 512    begin
 513       null;
 514    end Set_Ceiling;
 515
 516    -----------
 517    -- Sleep --
 518    -----------
 519
 520    procedure Sleep
 521      (Self_ID : Task_Id;
 522       Reason  : System.Tasking.Task_States)
 523    is
 524       pragma Unreferenced (Reason);
 525
 526    begin
 527       pragma Assert (Self_ID = Self);
 528
 529       if Single_Lock then
 530          Cond_Wait (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
 531       else
 532          Cond_Wait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
 533       end if;
 534
 535       if Self_ID.Deferral_Level = 0
 536         and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
 537       then
 538          Unlock (Self_ID);
 539          raise Standard'Abort_Signal;
 540       end if;
 541    end Sleep;
 542
 543    -----------------
 544    -- Timed_Sleep --
 545    -----------------
 546
 547    --  This is for use within the run-time system, so abort is assumed to be
 548    --  already deferred, and the caller should be holding its own ATCB lock.
 549
 550    procedure Timed_Sleep
 551      (Self_ID  : Task_Id;
 552       Time     : Duration;
 553       Mode     : ST.Delay_Modes;
 554       Reason   : System.Tasking.Task_States;
 555       Timedout : out Boolean;
 556       Yielded  : out Boolean)
 557    is
 558       pragma Unreferenced (Reason);
 559       Check_Time : Duration := Monotonic_Clock;
 560       Rel_Time   : Duration;
 561       Abs_Time   : Duration;
 562
 563       Result : Integer;
 564       pragma Unreferenced (Result);
 565
 566       Local_Timedout : Boolean;
 567
 568    begin
 569       Timedout := True;
 570       Yielded  := False;
 571
 572       if Mode = Relative then
 573          Rel_Time := Time;
 574          Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
 575       else
 576          Rel_Time := Time - Check_Time;
 577          Abs_Time := Time;
 578       end if;
 579
 580       if Rel_Time > 0.0 then
 581          loop
 582             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 583
 584             if Single_Lock then
 585                Cond_Timed_Wait
 586                  (Self_ID.Common.LL.CV'Access,
 587                   Single_RTS_Lock'Access,
 588                   Rel_Time, Local_Timedout, Result);
 589             else
 590                Cond_Timed_Wait
 591                  (Self_ID.Common.LL.CV'Access,
 592                   Self_ID.Common.LL.L'Access,
 593                   Rel_Time, Local_Timedout, Result);
 594             end if;
 595
 596             Check_Time := Monotonic_Clock;
 597             exit when Abs_Time <= Check_Time;
 598
 599             if not Local_Timedout then
 600
 601                --  Somebody may have called Wakeup for us
 602
 603                Timedout := False;
 604                exit;
 605             end if;
 606
 607             Rel_Time := Abs_Time - Check_Time;
 608          end loop;
 609       end if;
 610    end Timed_Sleep;
 611
 612    -----------------
 613    -- Timed_Delay --
 614    -----------------
 615
 616    procedure Timed_Delay
 617      (Self_ID : Task_Id;
 618       Time    : Duration;
 619       Mode    : ST.Delay_Modes)
 620    is
 621       Check_Time : Duration := Monotonic_Clock;
 622       Rel_Time   : Duration;
 623       Abs_Time   : Duration;
 624
 625       Timedout : Boolean;
 626       Result   : Integer;
 627       pragma Unreferenced (Timedout, Result);
 628
 629    begin
 630       if Single_Lock then
 631          Lock_RTS;
 632       end if;
 633
 634       Write_Lock (Self_ID);
 635
 636       if Mode = Relative then
 637          Rel_Time := Time;
 638          Abs_Time := Time + Check_Time;
 639       else
 640          Rel_Time := Time - Check_Time;
 641          Abs_Time := Time;
 642       end if;
 643
 644       if Rel_Time > 0.0 then
 645          Self_ID.Common.State := Delay_Sleep;
 646
 647          loop
 648             exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
 649
 650             if Single_Lock then
 651                Cond_Timed_Wait
 652                  (Self_ID.Common.LL.CV'Access,
 653                   Single_RTS_Lock'Access,
 654                   Rel_Time, Timedout, Result);
 655             else
 656                Cond_Timed_Wait
 657                  (Self_ID.Common.LL.CV'Access,
 658                   Self_ID.Common.LL.L'Access,
 659                   Rel_Time, Timedout, Result);
 660             end if;
 661
 662             Check_Time := Monotonic_Clock;
 663             exit when Abs_Time <= Check_Time;
 664
 665             Rel_Time := Abs_Time - Check_Time;
 666          end loop;
 667
 668          Self_ID.Common.State := Runnable;
 669       end if;
 670
 671       Unlock (Self_ID);
 672
 673       if Single_Lock then
 674          Unlock_RTS;
 675       end if;
 676
 677       Yield;
 678    end Timed_Delay;
 679
 680    ------------
 681    -- Wakeup --
 682    ------------
 683
 684    procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
 685       pragma Unreferenced (Reason);
 686    begin
 687       Cond_Signal (T.Common.LL.CV'Access);
 688    end Wakeup;
 689
 690    -----------
 691    -- Yield --
 692    -----------
 693
 694    procedure Yield (Do_Yield : Boolean := True) is
 695    begin
 696       if Do_Yield then
 697          SwitchToThread;
 698
 699       elsif Annex_D then
 700          --  If running with Annex-D semantics we need a delay
 701          --  above 0 milliseconds here otherwise processes give
 702          --  enough time to the other tasks to have a chance to
 703          --  run.
 704          --
 705          --  This makes cxd8002 ACATS pass on Windows.
 706
 707          Sleep (1);
 708       end if;
 709    end Yield;
 710
 711    ------------------
 712    -- Set_Priority --
 713    ------------------
 714
 715    type Prio_Array_Type is array (System.Any_Priority) of Integer;
 716    pragma Atomic_Components (Prio_Array_Type);
 717
 718    Prio_Array : Prio_Array_Type;
 719    --  Global array containing the id of the currently running task for
 720    --  each priority.
 721    --
 722    --  Note: we assume that we are on a single processor with run-til-blocked
 723    --  scheduling.
 724
 725    procedure Set_Priority
 726      (T                   : Task_Id;
 727       Prio                : System.Any_Priority;
 728       Loss_Of_Inheritance : Boolean := False)
 729    is
 730       Res        : BOOL;
 731       Array_Item : Integer;
 732
 733    begin
 734       Res := SetThreadPriority
 735         (T.Common.LL.Thread, Interfaces.C.int (Underlying_Priorities (Prio)));
 736       pragma Assert (Res = Win32.TRUE);
 737
 738       if Dispatching_Policy = 'F' or else Get_Policy (Prio) = 'F' then
 739
 740          --  Annex D requirement [RM D.2.2 par. 9]:
 741          --    If the task drops its priority due to the loss of inherited
 742          --    priority, it is added at the head of the ready queue for its
 743          --    new active priority.
 744
 745          if Loss_Of_Inheritance
 746            and then Prio < T.Common.Current_Priority
 747          then
 748             Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
 749             Prio_Array (T.Common.Base_Priority) := Array_Item;
 750
 751             loop
 752                --  Let some processes a chance to arrive
 753
 754                Yield;
 755
 756                --  Then wait for our turn to proceed
 757
 758                exit when Array_Item = Prio_Array (T.Common.Base_Priority)
 759                  or else Prio_Array (T.Common.Base_Priority) = 1;
 760             end loop;
 761
 762             Prio_Array (T.Common.Base_Priority) :=
 763               Prio_Array (T.Common.Base_Priority) - 1;
 764          end if;
 765       end if;
 766
 767       T.Common.Current_Priority := Prio;
 768    end Set_Priority;
 769
 770    ------------------
 771    -- Get_Priority --
 772    ------------------
 773
 774    function Get_Priority (T : Task_Id) return System.Any_Priority is
 775    begin
 776       return T.Common.Current_Priority;
 777    end Get_Priority;
 778
 779    ----------------
 780    -- Enter_Task --
 781    ----------------
 782
 783    --  There were two paths were we needed to call Enter_Task :
 784    --  1) from System.Task_Primitives.Operations.Initialize
 785    --  2) from System.Tasking.Stages.Task_Wrapper
 786
 787    --  The thread initialisation has to be done only for the first case
 788
 789    --  This is because the GetCurrentThread NT call does not return the real
 790    --  thread handler but only a "pseudo" one. It is not possible to release
 791    --  the thread handle and free the system resources from this "pseudo"
 792    --  handle. So we really want to keep the real thread handle set in
 793    --  System.Task_Primitives.Operations.Create_Task during thread creation.
 794
 795    procedure Enter_Task (Self_ID : Task_Id) is
 796       procedure Init_Float;
 797       pragma Import (C, Init_Float, "__gnat_init_float");
 798       --  Properly initializes the FPU for x86 systems
 799
 800    begin
 801       Specific.Set (Self_ID);
 802       Init_Float;
 803
 804       if Self_ID.Common.Task_Info /= null
 805         and then
 806           Self_ID.Common.Task_Info.CPU >= CPU_Number (Number_Of_Processors)
 807       then
 808          raise Invalid_CPU_Number;
 809       end if;
 810
 811       Self_ID.Common.LL.Thread_Id := GetCurrentThreadId;
 812
 813       Lock_RTS;
 814
 815       for J in Known_Tasks'Range loop
 816          if Known_Tasks (J) = null then
 817             Known_Tasks (J) := Self_ID;
 818             Self_ID.Known_Tasks_Index := J;
 819             exit;
 820          end if;
 821       end loop;
 822
 823       Unlock_RTS;
 824    end Enter_Task;
 825
 826    --------------
 827    -- New_ATCB --
 828    --------------
 829
 830    function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
 831    begin
 832       return new Ada_Task_Control_Block (Entry_Num);
 833    end New_ATCB;
 834
 835    -------------------
 836    -- Is_Valid_Task --
 837    -------------------
 838
 839    function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
 840
 841    -----------------------------
 842    -- Register_Foreign_Thread --
 843    -----------------------------
 844
 845    function Register_Foreign_Thread return Task_Id is
 846    begin
 847       if Is_Valid_Task then
 848          return Self;
 849       else
 850          return Register_Foreign_Thread (GetCurrentThread);
 851       end if;
 852    end Register_Foreign_Thread;
 853
 854    --------------------
 855    -- Initialize_TCB --
 856    --------------------
 857
 858    procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
 859    begin
 860       --  Initialize thread ID to 0, this is needed to detect threads that
 861       --  are not yet activated.
 862
 863       Self_ID.Common.LL.Thread := 0;
 864
 865       Initialize_Cond (Self_ID.Common.LL.CV'Access);
 866
 867       if not Single_Lock then
 868          Initialize_Lock (Self_ID.Common.LL.L'Access, ATCB_Level);
 869       end if;
 870
 871       Succeeded := True;
 872    end Initialize_TCB;
 873
 874    -----------------
 875    -- Create_Task --
 876    -----------------
 877
 878    procedure Create_Task
 879      (T          : Task_Id;
 880       Wrapper    : System.Address;
 881       Stack_Size : System.Parameters.Size_Type;
 882       Priority   : System.Any_Priority;
 883       Succeeded  : out Boolean)
 884    is
 885       Initial_Stack_Size : constant := 1024;
 886       --  We set the initial stack size to 1024. On Windows version prior to XP
 887       --  there is no way to fix a task stack size. Only the initial stack size
 888       --  can be set, the operating system will raise the task stack size if
 889       --  needed.
 890
 891       function Is_Windows_XP return Integer;
 892       pragma Import (C, Is_Windows_XP, "__gnat_is_windows_xp");
 893       --  Returns 1 if running on Windows XP
 894
 895       hTask          : HANDLE;
 896       TaskId         : aliased DWORD;
 897       pTaskParameter : Win32.PVOID;
 898       Result         : DWORD;
 899       Entry_Point    : PTHREAD_START_ROUTINE;
 900
 901    begin
 902       pTaskParameter := To_Address (T);
 903
 904       Entry_Point := To_PTHREAD_START_ROUTINE (Wrapper);
 905
 906       if Is_Windows_XP = 1 then
 907          hTask := CreateThread
 908            (null,
 909             DWORD (Stack_Size),
 910             Entry_Point,
 911             pTaskParameter,
 912             DWORD (Create_Suspended) or
 913               DWORD (Stack_Size_Param_Is_A_Reservation),
 914             TaskId'Unchecked_Access);
 915       else
 916          hTask := CreateThread
 917            (null,
 918             Initial_Stack_Size,
 919             Entry_Point,
 920             pTaskParameter,
 921             DWORD (Create_Suspended),
 922             TaskId'Unchecked_Access);
 923       end if;
 924
 925       --  Step 1: Create the thread in blocked mode
 926
 927       if hTask = 0 then
 928          Succeeded := False;
 929          return;
 930       end if;
 931
 932       --  Step 2: set its TCB
 933
 934       T.Common.LL.Thread := hTask;
 935
 936       --  Step 3: set its priority (child has inherited priority from parent)
 937
 938       Set_Priority (T, Priority);
 939
 940       if Time_Slice_Val = 0
 941         or else Dispatching_Policy = 'F'
 942         or else Get_Policy (Priority) = 'F'
 943       then
 944          --  Here we need Annex D semantics so we disable the NT priority
 945          --  boost. A priority boost is temporarily given by the system to a
 946          --  thread when it is taken out of a wait state.
 947
 948          SetThreadPriorityBoost (hTask, DisablePriorityBoost => Win32.TRUE);
 949       end if;
 950
 951       --  Step 4: Handle Task_Info
 952
 953       if T.Common.Task_Info /= null then
 954          if T.Common.Task_Info.CPU /= Task_Info.Any_CPU then
 955             Result := SetThreadIdealProcessor (hTask, T.Common.Task_Info.CPU);
 956             pragma Assert (Result = 1);
 957          end if;
 958       end if;
 959
 960       --  Step 5: Now, start it for good:
 961
 962       Result := ResumeThread (hTask);
 963       pragma Assert (Result = 1);
 964
 965       Succeeded := Result = 1;
 966    end Create_Task;
 967
 968    ------------------
 969    -- Finalize_TCB --
 970    ------------------
 971
 972    procedure Finalize_TCB (T : Task_Id) is
 973       Self_ID   : Task_Id := T;
 974       Result    : DWORD;
 975       Succeeded : BOOL;
 976       Is_Self   : constant Boolean := T = Self;
 977
 978       procedure Free is new
 979         Ada.Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
 980
 981    begin
 982       if not Single_Lock then
 983          Finalize_Lock (T.Common.LL.L'Access);
 984       end if;
 985
 986       Finalize_Cond (T.Common.LL.CV'Access);
 987
 988       if T.Known_Tasks_Index /= -1 then
 989          Known_Tasks (T.Known_Tasks_Index) := null;
 990       end if;
 991
 992       if Self_ID.Common.LL.Thread /= 0 then
 993
 994          --  This task has been activated. Wait for the thread to terminate
 995          --  then close it. This is needed to release system resources.
 996
 997          Result := WaitForSingleObject (T.Common.LL.Thread, Wait_Infinite);
 998          pragma Assert (Result /= WAIT_FAILED);
 999          Succeeded := CloseHandle (T.Common.LL.Thread);
1000          pragma Assert (Succeeded = Win32.TRUE);
1001       end if;
1002
1003       Free (Self_ID);
1004
1005       if Is_Self then
1006          Specific.Set (null);
1007       end if;
1008    end Finalize_TCB;
1009
1010    ---------------
1011    -- Exit_Task --
1012    ---------------
1013
1014    procedure Exit_Task is
1015    begin
1016       Specific.Set (null);
1017    end Exit_Task;
1018
1019    ----------------
1020    -- Abort_Task --
1021    ----------------
1022
1023    procedure Abort_Task (T : Task_Id) is
1024       pragma Unreferenced (T);
1025    begin
1026       null;
1027    end Abort_Task;
1028
1029    ----------------------
1030    -- Environment_Task --
1031    ----------------------
1032
1033    function Environment_Task return Task_Id is
1034    begin
1035       return Environment_Task_Id;
1036    end Environment_Task;
1037
1038    --------------
1039    -- Lock_RTS --
1040    --------------
1041
1042    procedure Lock_RTS is
1043    begin
1044       Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1045    end Lock_RTS;
1046
1047    ----------------
1048    -- Unlock_RTS --
1049    ----------------
1050
1051    procedure Unlock_RTS is
1052    begin
1053       Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1054    end Unlock_RTS;
1055
1056    ----------------
1057    -- Initialize --
1058    ----------------
1059
1060    procedure Initialize (Environment_Task : Task_Id) is
1061       Discard : BOOL;
1062       pragma Unreferenced (Discard);
1063
1064    begin
1065       Environment_Task_Id := Environment_Task;
1066       OS_Primitives.Initialize;
1067       Interrupt_Management.Initialize;
1068
1069       if Time_Slice_Val = 0 or else Dispatching_Policy = 'F' then
1070          --  Here we need Annex D semantics, switch the current process to the
1071          --  Realtime_Priority_Class.
1072
1073          Discard := OS_Interface.SetPriorityClass
1074                       (GetCurrentProcess, Realtime_Priority_Class);
1075
1076          Annex_D := True;
1077       end if;
1078
1079       TlsIndex := TlsAlloc;
1080
1081       --  Initialize the lock used to synchronize chain of all ATCBs
1082
1083       Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1084
1085       Environment_Task.Common.LL.Thread := GetCurrentThread;
1086       Enter_Task (Environment_Task);
1087    end Initialize;
1088
1089    ---------------------
1090    -- Monotonic_Clock --
1091    ---------------------
1092
1093    function Monotonic_Clock return Duration
1094      renames System.OS_Primitives.Monotonic_Clock;
1095
1096    -------------------
1097    -- RT_Resolution --
1098    -------------------
1099
1100    function RT_Resolution return Duration is
1101    begin
1102       return 0.000_001; --  1 micro-second
1103    end RT_Resolution;
1104
1105    ----------------
1106    -- Initialize --
1107    ----------------
1108
1109    procedure Initialize (S : in out Suspension_Object) is
1110    begin
1111       --  Initialize internal state. It is always initialized to False (ARM
1112       --  D.10 par. 6).
1113
1114       S.State := False;
1115       S.Waiting := False;
1116
1117       --  Initialize internal mutex
1118
1119       InitializeCriticalSection (S.L'Access);
1120
1121       --  Initialize internal condition variable
1122
1123       S.CV := CreateEvent (null, Win32.TRUE, Win32.FALSE, Null_Ptr);
1124       pragma Assert (S.CV /= 0);
1125    end Initialize;
1126
1127    --------------
1128    -- Finalize --
1129    --------------
1130
1131    procedure Finalize (S : in out Suspension_Object) is
1132       Result : BOOL;
1133    begin
1134       --  Destroy internal mutex
1135
1136       DeleteCriticalSection (S.L'Access);
1137
1138       --  Destroy internal condition variable
1139
1140       Result := CloseHandle (S.CV);
1141       pragma Assert (Result = Win32.TRUE);
1142    end Finalize;
1143
1144    -------------------
1145    -- Current_State --
1146    -------------------
1147
1148    function Current_State (S : Suspension_Object) return Boolean is
1149    begin
1150       --  We do not want to use lock on this read operation. State is marked
1151       --  as Atomic so that we ensure that the value retrieved is correct.
1152
1153       return S.State;
1154    end Current_State;
1155
1156    ---------------
1157    -- Set_False --
1158    ---------------
1159
1160    procedure Set_False (S : in out Suspension_Object) is
1161    begin
1162       SSL.Abort_Defer.all;
1163
1164       EnterCriticalSection (S.L'Access);
1165
1166       S.State := False;
1167
1168       LeaveCriticalSection (S.L'Access);
1169
1170       SSL.Abort_Undefer.all;
1171    end Set_False;
1172
1173    --------------
1174    -- Set_True --
1175    --------------
1176
1177    procedure Set_True (S : in out Suspension_Object) is
1178       Result : BOOL;
1179    begin
1180       SSL.Abort_Defer.all;
1181
1182       EnterCriticalSection (S.L'Access);
1183
1184       --  If there is already a task waiting on this suspension object then
1185       --  we resume it, leaving the state of the suspension object to False,
1186       --  as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
1187       --  the state to True.
1188
1189       if S.Waiting then
1190          S.Waiting := False;
1191          S.State := False;
1192
1193          Result := SetEvent (S.CV);
1194          pragma Assert (Result = Win32.TRUE);
1195       else
1196          S.State := True;
1197       end if;
1198
1199       LeaveCriticalSection (S.L'Access);
1200
1201       SSL.Abort_Undefer.all;
1202    end Set_True;
1203
1204    ------------------------
1205    -- Suspend_Until_True --
1206    ------------------------
1207
1208    procedure Suspend_Until_True (S : in out Suspension_Object) is
1209       Result      : DWORD;
1210       Result_Bool : BOOL;
1211    begin
1212       SSL.Abort_Defer.all;
1213
1214       EnterCriticalSection (S.L'Access);
1215
1216       if S.Waiting then
1217          --  Program_Error must be raised upon calling Suspend_Until_True
1218          --  if another task is already waiting on that suspension object
1219          --  (ARM D.10 par. 10).
1220
1221          LeaveCriticalSection (S.L'Access);
1222
1223          SSL.Abort_Undefer.all;
1224
1225          raise Program_Error;
1226       else
1227          --  Suspend the task if the state is False. Otherwise, the task
1228          --  continues its execution, and the state of the suspension object
1229          --  is set to False (ARM D.10 par. 9).
1230
1231          if S.State then
1232             S.State := False;
1233
1234             LeaveCriticalSection (S.L'Access);
1235
1236             SSL.Abort_Undefer.all;
1237          else
1238             S.Waiting := True;
1239
1240             --  Must reset CV BEFORE L is unlocked
1241
1242             Result_Bool := ResetEvent (S.CV);
1243             pragma Assert (Result_Bool = Win32.TRUE);
1244
1245             LeaveCriticalSection (S.L'Access);
1246
1247             SSL.Abort_Undefer.all;
1248
1249             Result := WaitForSingleObject (S.CV, Wait_Infinite);
1250             pragma Assert (Result = 0);
1251          end if;
1252       end if;
1253    end Suspend_Until_True;
1254
1255    ----------------
1256    -- Check_Exit --
1257    ----------------
1258
1259    --  Dummy versions.  The only currently working versions is for solaris
1260    --  (native).
1261
1262    function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1263       pragma Unreferenced (Self_ID);
1264    begin
1265       return True;
1266    end Check_Exit;
1267
1268    --------------------
1269    -- Check_No_Locks --
1270    --------------------
1271
1272    function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1273       pragma Unreferenced (Self_ID);
1274    begin
1275       return True;
1276    end Check_No_Locks;
1277
1278    ------------------
1279    -- Suspend_Task --
1280    ------------------
1281
1282    function Suspend_Task
1283      (T           : ST.Task_Id;
1284       Thread_Self : Thread_Id) return Boolean
1285    is
1286    begin
1287       if T.Common.LL.Thread /= Thread_Self then
1288          return SuspendThread (T.Common.LL.Thread) = NO_ERROR;
1289       else
1290          return True;
1291       end if;
1292    end Suspend_Task;
1293
1294    -----------------
1295    -- Resume_Task --
1296    -----------------
1297
1298    function Resume_Task
1299      (T           : ST.Task_Id;
1300       Thread_Self : Thread_Id) return Boolean
1301    is
1302    begin
1303       if T.Common.LL.Thread /= Thread_Self then
1304          return ResumeThread (T.Common.LL.Thread) = NO_ERROR;
1305       else
1306          return True;
1307       end if;
1308    end Resume_Task;
1309
1310    --------------------
1311    -- Stop_All_Tasks --
1312    --------------------
1313
1314    procedure Stop_All_Tasks is
1315    begin
1316       null;
1317    end Stop_All_Tasks;
1318
1319    ---------------
1320    -- Stop_Task --
1321    ---------------
1322
1323    function Stop_Task (T : ST.Task_Id) return Boolean is
1324       pragma Unreferenced (T);
1325    begin
1326       return False;
1327    end Stop_Task;
1328
1329    -------------------
1330    -- Continue_Task --
1331    -------------------
1332
1333    function Continue_Task (T : ST.Task_Id) return Boolean is
1334       pragma Unreferenced (T);
1335    begin
1336       return False;
1337    end Continue_Task;
1338
1339 end System.Task_Primitives.Operations;