1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- S Y S T E M . F I N A L I Z A T I O N _ I M P L E M E N T A T I O N --
9 -- Copyright (C) 1992-2001 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, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, 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 ------------------------------------------------------------------------------
36 with Ada
.Unchecked_Conversion
;
37 with System
.Storage_Elements
;
38 with System
.Soft_Links
;
40 package body System
.Finalization_Implementation
is
43 use System
.Finalization_Root
;
45 package SSL
renames System
.Soft_Links
;
47 package SSE
renames System
.Storage_Elements
;
48 use type SSE
.Storage_Offset
;
50 -----------------------
51 -- Local Subprograms --
52 -----------------------
54 function To_Finalizable_Ptr
is
55 new Ada
.Unchecked_Conversion
(Address
, Finalizable_Ptr
);
58 new Ada
.Unchecked_Conversion
(Finalizable_Ptr
, Address
);
60 type RC_Ptr
is access all Record_Controller
;
63 new Ada
.Unchecked_Conversion
(Address
, RC_Ptr
);
65 procedure Raise_Exception_No_Defer
67 Message
: in String := "");
68 pragma Import
(Ada
, Raise_Exception_No_Defer
,
69 "ada__exceptions__raise_exception_no_defer");
70 pragma No_Return
(Raise_Exception_No_Defer
);
71 -- Raise an exception without deferring abort. Note that we have to
72 -- use this rather kludgy Ada Import interface, since this subprogram
73 -- is not available in the visible spec of Ada.Exceptions.
75 procedure Raise_From_Finalize
78 E_Occ
: Exception_Occurrence
);
79 -- Deal with an exception raised during finalization of a list. L is a
80 -- pointer to the list of element not yet finalized. From_Abort is true
81 -- if the finalization actions come from an abort rather than a normal
82 -- exit. E_Occ represents the exception being raised.
84 function RC_Offset
(T
: Ada
.Tags
.Tag
) return SSE
.Storage_Offset
;
85 pragma Import
(Ada
, RC_Offset
, "ada__tags__get_rc_offset");
87 function Parent_Size
(Obj
: Address
) return SSE
.Storage_Count
;
88 pragma Import
(Ada
, Parent_Size
, "ada__tags__parent_size");
90 function Get_RC_Dynamically
(Obj
: Address
) return Address
;
91 -- Given an the address of an object (obj) of a tagged extension with
92 -- controlled component, computes the address of the record controller
93 -- located just after the _parent field
99 procedure Adjust
(Object
: in out Record_Controller
) is
101 First_Comp
: Finalizable_Ptr
;
102 My_Offset
: constant SSE
.Storage_Offset
:=
103 Object
.My_Address
- Object
'Address;
105 procedure Ptr_Adjust
(Ptr
: in out Finalizable_Ptr
);
106 -- Subtract the offset to the pointer
108 procedure Reverse_Adjust
(P
: Finalizable_Ptr
);
109 -- Adjust the components in the reverse order in which they are stored
110 -- on the finalization list. (Adjust and Finalization are not done in
113 procedure Ptr_Adjust
(Ptr
: in out Finalizable_Ptr
) is
116 Ptr
:= To_Finalizable_Ptr
(To_Addr
(Ptr
) - My_Offset
);
120 procedure Reverse_Adjust
(P
: Finalizable_Ptr
) is
124 Reverse_Adjust
(P
.Next
);
126 Object
.F
:= P
; -- Successfully adjusted, so place in list.
130 -- Start of processing for Adjust
133 -- Adjust the components and their finalization pointers next.
134 -- We must protect against an exception in some call to Adjust, so
135 -- we keep pointing to the list of successfully adjusted components,
136 -- which can be finalized if an exception is raised.
138 First_Comp
:= Object
.F
;
139 Object
.F
:= null; -- nothing adjusted yet.
140 Ptr_Adjust
(First_Comp
); -- set addresss of first component.
141 Reverse_Adjust
(First_Comp
);
143 -- Then Adjust the controller itself
145 Object
.My_Address
:= Object
'Address;
149 -- Finalize those components that were successfully adjusted, and
150 -- propagate exception. The object itself is not yet attached to
151 -- global finalization list, so we cannot rely on the outer call
152 -- to Clean to take care of these components.
158 --------------------------
159 -- Attach_To_Final_List --
160 --------------------------
162 procedure Attach_To_Final_List
163 (L
: in out Finalizable_Ptr
;
164 Obj
: in out Finalizable
;
165 Nb_Link
: Short_Short_Integer)
168 -- Simple case: attachement to a one way list
172 L
:= Obj
'Unchecked_Access;
174 -- Dynamically allocated objects: they are attached to a doubly
175 -- linked list, so that an element can be finalized at any moment
176 -- by means of an unchecked deallocation. Attachement is
177 -- protected against multi-threaded access.
179 elsif Nb_Link
= 2 then
181 Locked_Processing
: begin
184 Obj
.Prev
:= L
.Next
.Prev
;
185 L
.Next
.Prev
:= Obj
'Unchecked_Access;
186 L
.Next
:= Obj
'Unchecked_Access;
193 end Locked_Processing
;
195 -- Attachement of arrays to the final list (used only for objects
196 -- returned by function). Obj, in this case is the last element,
197 -- but all other elements are already threaded after it. We just
198 -- attach the rest of the final list at the end of the array list.
200 elsif Nb_Link
= 3 then
202 P
: Finalizable_Ptr
:= Obj
'Unchecked_Access;
205 while P
.Next
/= null loop
210 L
:= Obj
'Unchecked_Access;
214 end Attach_To_Final_List
;
216 ---------------------
217 -- Deep_Tag_Adjust --
218 ---------------------
220 procedure Deep_Tag_Adjust
221 (L
: in out SFR
.Finalizable_Ptr
;
223 B
: Short_Short_Integer)
225 V
: constant SFR
.Finalizable_Ptr
:= To_Finalizable_Ptr
(A
);
226 Offset
: constant SSE
.Storage_Offset
:= RC_Offset
(V
'Tag);
231 -- Has controlled components
235 Controller
:= To_RC_Ptr
(A
+ Offset
);
237 Controller
:= To_RC_Ptr
(Get_RC_Dynamically
(A
));
240 Adjust
(Controller
.all);
241 Attach_To_Final_List
(L
, Controller
.all, B
);
245 elsif V
.all in Finalizable
then
247 Attach_To_Final_List
(L
, Finalizable
(V
.all), 1);
251 ---------------------
252 -- Deep_Tag_Attach --
253 ----------------------
255 procedure Deep_Tag_Attach
256 (L
: in out SFR
.Finalizable_Ptr
;
258 B
: Short_Short_Integer)
260 V
: constant SFR
.Finalizable_Ptr
:= To_Finalizable_Ptr
(A
);
261 Offset
: constant SSE
.Storage_Offset
:= RC_Offset
(V
'Tag);
268 Controller
:= To_RC_Ptr
(A
+ Offset
);
270 Controller
:= To_RC_Ptr
(Get_RC_Dynamically
(A
));
273 Attach_To_Final_List
(L
, Controller
.all, B
);
277 elsif V
.all in Finalizable
then
278 Attach_To_Final_List
(L
, V
.all, B
);
282 -----------------------
283 -- Deep_Tag_Finalize --
284 -----------------------
286 procedure Deep_Tag_Finalize
287 (L
: in out SFR
.Finalizable_Ptr
;
291 pragma Warnings
(Off
, L
);
293 V
: constant SFR
.Finalizable_Ptr
:= To_Finalizable_Ptr
(A
);
294 Offset
: constant SSE
.Storage_Offset
:= RC_Offset
(V
'Tag);
299 -- Has controlled components
303 Controller
:= To_RC_Ptr
(A
+ Offset
);
305 Controller
:= To_RC_Ptr
(Get_RC_Dynamically
(A
));
309 Finalize_One
(Controller
.all);
311 Finalize
(Controller
.all);
316 elsif V
.all in Finalizable
then
318 Finalize_One
(V
.all);
323 end Deep_Tag_Finalize
;
325 -------------------------
326 -- Deep_Tag_Initialize --
327 -------------------------
329 procedure Deep_Tag_Initialize
330 (L
: in out SFR
.Finalizable_Ptr
;
332 B
: Short_Short_Integer)
334 V
: constant SFR
.Finalizable_Ptr
:= To_Finalizable_Ptr
(A
);
335 Offset
: constant SSE
.Storage_Offset
:= RC_Offset
(V
'Tag);
340 -- This procedure should not be called if the object has no
341 -- controlled components
347 -- Has controlled components
351 Controller
:= To_RC_Ptr
(A
+ Offset
);
353 Controller
:= To_RC_Ptr
(Get_RC_Dynamically
(A
));
357 Initialize
(Controller
.all);
358 Attach_To_Final_List
(L
, Controller
.all, B
);
362 if V
.all in Finalizable
then
364 Attach_To_Final_List
(Controller
.F
, Finalizable
(Controller
.all), 1);
366 end Deep_Tag_Initialize
;
368 -----------------------------
369 -- Detach_From_Final_List --
370 -----------------------------
372 -- We know that the detach object is neither at the beginning nor at the
373 -- end of the list, thank's to the dummy First and Last Elements but the
374 -- object may not be attached at all if it is Finalize_Storage_Only
376 procedure Detach_From_Final_List
(Obj
: in out Finalizable
) is
379 -- When objects are not properly attached to a doubly linked
380 -- list do not try to detach them. The only case where it can
381 -- happen is when dealing with Finalize_Storage_Only objects
382 -- which are not always attached.
384 if Obj
.Next
/= null and then Obj
.Prev
/= null then
386 Obj
.Next
.Prev
:= Obj
.Prev
;
387 Obj
.Prev
.Next
:= Obj
.Next
;
395 end Detach_From_Final_List
;
401 procedure Finalize
(Object
: in out Limited_Record_Controller
) is
403 Finalize_List
(Object
.F
);
406 --------------------------
407 -- Finalize_Global_List --
408 --------------------------
410 procedure Finalize_Global_List
is
412 -- There are three case here:
413 -- a. the application uses tasks, in which case Finalize_Global_Tasks
414 -- will defer abortion
415 -- b. the application doesn't use tasks but uses other tasking
416 -- constructs, such as ATCs and protected objects. In this case,
417 -- the binder will call Finalize_Global_List instead of
418 -- Finalize_Global_Tasks, letting abort undeferred, and leading
419 -- to assertion failures in the GNULL
420 -- c. the application doesn't use any tasking construct in which case
421 -- deferring abort isn't necessary.
423 -- Until another solution is found to deal with case b, we need to
424 -- call abort_defer here to pass the checks, but we do not need to
425 -- undefer abortion, since Finalize_Global_List is the last procedure
426 -- called before exiting the partition.
429 Finalize_List
(Global_Final_List
);
430 end Finalize_Global_List
;
436 procedure Finalize_List
(L
: Finalizable_Ptr
) is
437 P
: Finalizable_Ptr
:= L
;
440 type Fake_Exception_Occurrence
is record
443 type Ptr
is access all Fake_Exception_Occurrence
;
445 -- Let's get the current exception before starting to finalize in
446 -- order to check if we are in the abort case if an exception is
449 function To_Ptr
is new
450 Ada
.Unchecked_Conversion
(Exception_Occurrence_Access
, Ptr
);
452 To_Ptr
(System
.Soft_Links
.Get_Current_Excep
.all).Id
;
462 when E_Occ
: others =>
463 Raise_From_Finalize
(
465 X
= Standard
'Abort_Signal'Identity,
473 procedure Finalize_One (Obj : in out Finalizable) is
475 Detach_From_Final_List (Obj);
479 when E_Occ : others => Raise_From_Finalize (null, False, E_Occ);
482 ------------------------
483 -- Get_RC_Dynamically --
484 ------------------------
486 function Get_RC_Dynamically (Obj : Address) return Address is
488 -- define a faked record controller to avoid generating
489 -- unnecessary expanded code for controlled types
491 type Faked_Record_Controller is record
492 Tag, Prec, Next : Address;
495 -- Reconstruction of a type with characteristics
496 -- comparable to the original type
498 D : constant := Storage_Unit - 1;
500 type Faked_Type_Of_Obj is record
501 Parent : SSE.Storage_Array
502 (1 .. (Parent_Size (Obj) + D) / Storage_Unit);
503 Controller : Faked_Record_Controller;
506 type Obj_Ptr is access all Faked_Type_Of_Obj;
507 function To_Obj_Ptr is new Ada.Unchecked_Conversion (Address, Obj_Ptr);
510 return To_Obj_Ptr (Obj).Controller'Address;
511 end Get_RC_Dynamically;
517 procedure Initialize (Object : in out Limited_Record_Controller) is
518 pragma Warnings (Off, Object);
524 procedure Initialize (Object : in out Record_Controller) is
526 Object.My_Address := Object'Address;
529 -------------------------
530 -- Raise_From_Finalize --
531 -------------------------
533 procedure Raise_From_Finalize
534 (L : Finalizable_Ptr;
535 From_Abort : Boolean;
536 E_Occ : Exception_Occurrence)
538 Msg : constant String := Exception_Message (E_Occ);
539 P : Finalizable_Ptr := L;
543 -- We already got an exception. We now finalize the remainder of
544 -- the list, ignoring all further exceptions.
558 -- If finalization from an Abort, then nothing to do
563 -- If no message, then add our own message saying what happened
566 Raise_Exception_No_Defer
567 (E => Program_Error'Identity,
568 Message => "exception " &
569 Exception_Name (E_Occ) &
570 " raised during finalization");
572 -- If there was a message, pass it on
575 Raise_Exception_No_Defer (Program_Error'Identity, Msg);
577 end Raise_From_Finalize;
579 -- Initialization of package, set Adafinal soft link
582 SSL.Adafinal := Finalize_Global_List'Access;
584 end System.Finalization_Implementation;