1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . S O F T _ L I N K S --
9 -- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
11 -- GNAT 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. 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. 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 GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
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. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 -- This package contains a set of subprogram access variables that access
35 -- some low-level primitives that are different depending whether tasking is
36 -- involved or not (e.g. the Get/Set_Jmpbuf_Address that needs to provide a
37 -- different value for each task). To avoid dragging in the tasking runtimes
38 -- all the time, we use a system of soft links where the links are
39 -- initialized to non-tasking versions, and then if the tasking support is
40 -- initialized, they are set to the real tasking versions.
42 pragma Warnings
(Off
);
47 with System
.Stack_Checking
;
49 package System
.Soft_Links
is
50 pragma Warnings
(Off
);
51 pragma Preelaborate_05
;
54 subtype EOA
is Ada
.Exceptions
.Exception_Occurrence_Access
;
55 subtype EO
is Ada
.Exceptions
.Exception_Occurrence
;
57 function Current_Target_Exception
return EO
;
59 (Ada
, Current_Target_Exception
, "__gnat_current_target_exception");
60 -- Import this subprogram from the private part of Ada.Exceptions
62 -- First we have the access subprogram types used to establish the links.
63 -- The approach is to establish variables containing access subprogram
64 -- values, which by default point to dummy no tasking versions of routines.
66 type No_Param_Proc
is access procedure;
67 type Addr_Param_Proc
is access procedure (Addr
: Address
);
68 type EO_Param_Proc
is access procedure (Excep
: EO
);
70 type Get_Address_Call
is access function return Address
;
71 type Set_Address_Call
is access procedure (Addr
: Address
);
72 type Set_Address_Call2
is access procedure
73 (Self_ID
: Address
; Addr
: Address
);
75 type Get_Integer_Call
is access function return Integer;
76 type Set_Integer_Call
is access procedure (Len
: Integer);
78 type Get_EOA_Call
is access function return EOA
;
79 type Set_EOA_Call
is access procedure (Excep
: EOA
);
80 type Set_EO_Call
is access procedure (Excep
: EO
);
82 type Special_EO_Call
is access
83 procedure (Excep
: EO
:= Current_Target_Exception
);
85 type Timed_Delay_Call
is access
86 procedure (Time
: Duration; Mode
: Integer);
88 type Get_Stack_Access_Call
is access
89 function return Stack_Checking
.Stack_Access
;
91 type Task_Name_Call
is access
92 function return String;
94 -- Suppress checks on all these types, since we know the corrresponding
95 -- values can never be null (the soft links are always initialized).
97 pragma Suppress
(Access_Check
, No_Param_Proc
);
98 pragma Suppress
(Access_Check
, Addr_Param_Proc
);
99 pragma Suppress
(Access_Check
, EO_Param_Proc
);
100 pragma Suppress
(Access_Check
, Get_Address_Call
);
101 pragma Suppress
(Access_Check
, Set_Address_Call
);
102 pragma Suppress
(Access_Check
, Set_Address_Call2
);
103 pragma Suppress
(Access_Check
, Get_Integer_Call
);
104 pragma Suppress
(Access_Check
, Set_Integer_Call
);
105 pragma Suppress
(Access_Check
, Get_EOA_Call
);
106 pragma Suppress
(Access_Check
, Set_EOA_Call
);
107 pragma Suppress
(Access_Check
, Timed_Delay_Call
);
108 pragma Suppress
(Access_Check
, Get_Stack_Access_Call
);
109 pragma Suppress
(Access_Check
, Task_Name_Call
);
111 -- The following one is not related to tasking/no-tasking but to the
112 -- traceback decorators for exceptions.
114 type Traceback_Decorator_Wrapper_Call
is access
115 function (Traceback
: System
.Address
;
119 -- Declarations for the no tasking versions of the required routines
121 procedure Abort_Defer_NT
;
122 -- Defer task abort (non-tasking case, does nothing)
124 procedure Abort_Undefer_NT
;
125 -- Undefer task abort (non-tasking case, does nothing)
127 procedure Abort_Handler_NT
;
128 -- Handle task abort (non-tasking case, does nothing). Currently, only VMS
131 procedure Update_Exception_NT
(X
: EO
:= Current_Target_Exception
);
132 -- Handle exception setting. This routine is provided for targets that
133 -- have built-in exception handling such as the Java Virtual Machine.
134 -- Currently, only JGNAT uses this. See 4jexcept.ads for an explanation on
135 -- how this routine is used.
137 function Check_Abort_Status_NT
return Integer;
138 -- Returns Boolean'Pos (True) iff abort signal should raise
139 -- Standard.Abort_Signal.
141 procedure Task_Lock_NT
;
142 -- Lock out other tasks (non-tasking case, does nothing)
144 procedure Task_Unlock_NT
;
145 -- Release lock set by Task_Lock (non-tasking case, does nothing)
147 procedure Task_Termination_NT
(Excep
: EO
);
148 -- Handle task termination routines for the environment task (non-tasking
149 -- case, does nothing).
151 procedure Null_Finalize_Global_List
;
152 -- Finalize global list for controlled objects (does nothing)
154 procedure Adafinal_NT
;
155 -- Shuts down the runtime system (non-tasking case)
157 Abort_Defer
: No_Param_Proc
:= Abort_Defer_NT
'Access;
158 pragma Suppress
(Access_Check
, Abort_Defer
);
159 -- Defer task abort (task/non-task case as appropriate)
161 Abort_Undefer
: No_Param_Proc
:= Abort_Undefer_NT
'Access;
162 pragma Suppress
(Access_Check
, Abort_Undefer
);
163 -- Undefer task abort (task/non-task case as appropriate)
165 Abort_Handler
: No_Param_Proc
:= Abort_Handler_NT
'Access;
166 -- Handle task abort (task/non-task case as appropriate)
168 Update_Exception
: Special_EO_Call
:= Update_Exception_NT
'Access;
169 -- Handle exception setting and tasking polling when appropriate
171 Check_Abort_Status
: Get_Integer_Call
:= Check_Abort_Status_NT
'Access;
172 -- Called when Abort_Signal is delivered to the process. Checks to
173 -- see if signal should result in raising Standard.Abort_Signal.
175 Lock_Task
: No_Param_Proc
:= Task_Lock_NT
'Access;
176 -- Locks out other tasks. Preceding a section of code by Task_Lock and
177 -- following it by Task_Unlock creates a critical region. This is used
178 -- for ensuring that a region of non-tasking code (such as code used to
179 -- allocate memory) is tasking safe. Note that it is valid for calls to
180 -- Task_Lock/Task_Unlock to be nested, and this must work properly, i.e.
181 -- only the corresponding outer level Task_Unlock will actually unlock.
182 -- This routine also prevents against asynchronous aborts (abort is
185 Unlock_Task
: No_Param_Proc
:= Task_Unlock_NT
'Access;
186 -- Releases lock previously set by call to Lock_Task. In the nested case,
187 -- all nested locks must be released before other tasks competing for the
188 -- tasking lock are released.
190 -- In the non nested case, this routine terminates the protection against
191 -- asynchronous aborts introduced by Lock_Task (unless abort was already
192 -- deferred before the call to Lock_Task (e.g in a protected procedures).
194 -- Note: the recommended protocol for using Lock_Task and Unlock_Task
197 -- Locked_Processing : begin
198 -- System.Soft_Links.Lock_Task.all;
200 -- System.Soft_Links..Unlock_Task.all;
204 -- System.Soft_Links..Unlock_Task.all;
206 -- end Locked_Processing;
208 -- This ensures that the lock is not left set if an exception is raised
209 -- explicitly or implicitly during the critical locked region.
211 Task_Termination_Handler
: EO_Param_Proc
:= Task_Termination_NT
'Access;
212 -- Handle task termination routines (task/non-task case as appropriate)
214 Finalize_Global_List
: No_Param_Proc
:= Null_Finalize_Global_List
'Access;
215 -- Performs finalization of global list for controlled objects
217 Adafinal
: No_Param_Proc
:= Adafinal_NT
'Access;
218 -- Performs the finalization of the Ada Runtime
220 function Get_Jmpbuf_Address_NT
return Address
;
221 procedure Set_Jmpbuf_Address_NT
(Addr
: Address
);
223 Get_Jmpbuf_Address
: Get_Address_Call
:= Get_Jmpbuf_Address_NT
'Access;
224 Set_Jmpbuf_Address
: Set_Address_Call
:= Set_Jmpbuf_Address_NT
'Access;
226 function Get_Sec_Stack_Addr_NT
return Address
;
227 procedure Set_Sec_Stack_Addr_NT
(Addr
: Address
);
229 Get_Sec_Stack_Addr
: Get_Address_Call
:= Get_Sec_Stack_Addr_NT
'Access;
230 Set_Sec_Stack_Addr
: Set_Address_Call
:= Set_Sec_Stack_Addr_NT
'Access;
232 function Get_Exc_Stack_Addr_NT
return Address
;
233 Get_Exc_Stack_Addr
: Get_Address_Call
:= Get_Exc_Stack_Addr_NT
'Access;
235 function Get_Current_Excep_NT
return EOA
;
237 Get_Current_Excep
: Get_EOA_Call
:= Get_Current_Excep_NT
'Access;
239 function Get_Stack_Info_NT
return Stack_Checking
.Stack_Access
;
241 Get_Stack_Info
: Get_Stack_Access_Call
:= Get_Stack_Info_NT
'Access;
243 --------------------------
244 -- Master_Id Soft-Links --
245 --------------------------
247 -- Soft-Links are used for procedures that manipulate Master_Ids because
248 -- a Master_Id must be generated for access to limited class-wide types,
249 -- whose root may be extended with task components.
251 function Current_Master_NT
return Integer;
252 procedure Enter_Master_NT
;
253 procedure Complete_Master_NT
;
255 Current_Master
: Get_Integer_Call
:= Current_Master_NT
'Access;
256 Enter_Master
: No_Param_Proc
:= Enter_Master_NT
'Access;
257 Complete_Master
: No_Param_Proc
:= Complete_Master_NT
'Access;
259 ----------------------
260 -- Delay Soft-Links --
261 ----------------------
263 -- Soft-Links are used for procedures that manipulate time to avoid
264 -- dragging the tasking run time when using delay statements.
266 Timed_Delay
: Timed_Delay_Call
;
268 --------------------------
269 -- Task Name Soft-Links --
270 --------------------------
272 function Task_Name_NT
return String;
274 Task_Name
: Task_Name_Call
:= Task_Name_NT
'Access;
276 -------------------------------------
277 -- Exception Tracebacks Soft-Links --
278 -------------------------------------
280 Traceback_Decorator_Wrapper
: Traceback_Decorator_Wrapper_Call
;
281 -- Wrapper to the possible user specified traceback decorator to be
282 -- called during automatic output of exception data.
284 -- The nullity of this wrapper shall correspond to the nullity of the
285 -- current actual decorator. This is ensured first by the null initial
286 -- value of the corresponding variables, and then by Set_Trace_Decorator
289 pragma Atomic
(Traceback_Decorator_Wrapper
);
290 -- Since concurrent read/write operations may occur on this variable.
291 -- See the body of Tailored_Exception_Traceback in Ada.Exceptions for
292 -- a more detailed description of the potential problems.
294 ------------------------
295 -- Task Specific Data --
296 ------------------------
298 -- Here we define a single type that encapsulates the various task
299 -- specific data. This type is used to store the necessary data into
300 -- the Task_Control_Block or into a global variable in the non tasking
304 Pri_Stack_Info
: aliased Stack_Checking
.Stack_Info
;
305 -- Information on stack (Base/Limit/Size) that is used
306 -- by System.Stack_Checking. If this TSD does not belong to
307 -- the environment task, the Size field must be initialized
308 -- to the tasks requested stack size before the task can do
309 -- its first stack check.
311 pragma Warnings
(Off
);
312 Jmpbuf_Address
: System
.Address
:= System
.Null_Address
;
313 -- Address of jump buffer used to store the address of the
314 -- current longjmp/setjmp buffer for exception management.
315 -- These buffers are threaded into a stack, and the address
316 -- here is the top of the stack. A null address means that
317 -- no exception handler is currently active.
319 Sec_Stack_Addr
: System
.Address
:= System
.Null_Address
;
320 pragma Warnings
(On
);
321 -- Address of currently allocated secondary stack
323 Current_Excep
: aliased EO
;
324 -- Exception occurrence that contains the information for the
325 -- current exception. Note that any exception in the same task
326 -- destroys this information, so the data in this variable must
327 -- be copied out before another exception can occur.
329 -- Also act as a list of the active exceptions in the case of the GCC
330 -- exception mechanism, organized as a stack with the most recent first.
333 procedure Create_TSD
(New_TSD
: in out TSD
);
334 pragma Inline
(Create_TSD
);
335 -- Called from s-tassta when a new thread is created to perform
336 -- any required initialization of the TSD.
338 procedure Destroy_TSD
(Old_TSD
: in out TSD
);
339 pragma Inline
(Destroy_TSD
);
340 -- Called from s-tassta just before a thread is destroyed to perform
341 -- any required finalization.
343 function Get_GNAT_Exception
return Ada
.Exceptions
.Exception_Id
;
344 pragma Inline
(Get_GNAT_Exception
);
345 -- This function obtains the Exception_Id from the Exception_Occurrence
346 -- referenced by the Current_Excep field of the task specific data, i.e.
347 -- the call is equivalent to
348 -- Exception_Identity (Get_Current_Exception.all)
350 -- Export the Get/Set routines for the various Task Specific Data (TSD)
351 -- elements as callable subprograms instead of objects of access to
354 function Get_Jmpbuf_Address_Soft
return Address
;
355 procedure Set_Jmpbuf_Address_Soft
(Addr
: Address
);
356 pragma Inline
(Get_Jmpbuf_Address_Soft
);
357 pragma Inline
(Set_Jmpbuf_Address_Soft
);
359 function Get_Sec_Stack_Addr_Soft
return Address
;
360 procedure Set_Sec_Stack_Addr_Soft
(Addr
: Address
);
361 pragma Inline
(Get_Sec_Stack_Addr_Soft
);
362 pragma Inline
(Set_Sec_Stack_Addr_Soft
);
364 function Get_Exc_Stack_Addr_Soft
return Address
;
366 end System
.Soft_Links
;