1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . S T O R A G E _ P O O L S . S U B P O O L S --
9 -- Copyright (C) 2011-2023, Free Software Foundation, Inc. --
11 -- This specification is derived from the Ada Reference Manual for use with --
12 -- GNAT. The copyright notice above, and the license provisions that follow --
13 -- apply solely to the contents of the part following the private keyword. --
15 -- GNAT is free software; you can redistribute it and/or modify it under --
16 -- terms of the GNU General Public License as published by the Free Soft- --
17 -- ware Foundation; either version 3, or (at your option) any later ver- --
18 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
19 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
20 -- or FITNESS FOR A PARTICULAR PURPOSE. --
22 -- As a special exception under Section 7 of GPL version 3, you are granted --
23 -- additional permissions described in the GCC Runtime Library Exception, --
24 -- version 3.1, as published by the Free Software Foundation. --
26 -- You should have received a copy of the GNU General Public License and --
27 -- a copy of the GCC Runtime Library Exception along with this program; --
28 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
29 -- <http://www.gnu.org/licenses/>. --
31 -- GNAT was originally developed by the GNAT team at New York University. --
32 -- Extensive contributions were provided by Ada Core Technologies Inc. --
34 ------------------------------------------------------------------------------
36 with Ada
.Finalization
;
37 with System
.Finalization_Masters
;
38 with System
.Storage_Elements
;
40 package System
.Storage_Pools
.Subpools
is
43 type Root_Storage_Pool_With_Subpools
is abstract
44 new Root_Storage_Pool
with private;
45 pragma Preelaborable_Initialization
(Root_Storage_Pool_With_Subpools
);
46 -- The base for all implementations of Storage_Pool_With_Subpools. This
47 -- type is Limited_Controlled by derivation. To use subpools, an access
48 -- type must be associated with an implementation descending from type
49 -- Root_Storage_Pool_With_Subpools.
51 type Root_Subpool
is abstract tagged limited private;
52 pragma Preelaborable_Initialization
(Root_Subpool
);
53 -- The base for all implementations of Subpool. Objects of this type are
54 -- managed by the pool_with_subpools.
56 type Subpool_Handle
is access all Root_Subpool
'Class;
57 for Subpool_Handle
'Storage_Size use 0;
58 -- Since subpools are limited types by definition, a handle is instead used
59 -- to manage subpool abstractions.
61 overriding
procedure Allocate
62 (Pool
: in out Root_Storage_Pool_With_Subpools
;
63 Storage_Address
: out System
.Address
;
64 Size_In_Storage_Elements
: System
.Storage_Elements
.Storage_Count
;
65 Alignment
: System
.Storage_Elements
.Storage_Count
);
66 -- Allocate an object described by Size_In_Storage_Elements and Alignment
67 -- on the default subpool of Pool. Controlled types allocated through this
68 -- routine will NOT be handled properly.
70 procedure Allocate_From_Subpool
71 (Pool
: in out Root_Storage_Pool_With_Subpools
;
72 Storage_Address
: out System
.Address
;
73 Size_In_Storage_Elements
: System
.Storage_Elements
.Storage_Count
;
74 Alignment
: System
.Storage_Elements
.Storage_Count
;
75 Subpool
: not null Subpool_Handle
) is abstract;
77 -- ??? This precondition causes errors in simple tests, disabled for now
79 -- with Pre'Class => Pool_Of_Subpool (Subpool) = Pool'Access;
80 -- This routine requires implementation. Allocate an object described by
81 -- Size_In_Storage_Elements and Alignment on a subpool.
83 function Create_Subpool
84 (Pool
: in out Root_Storage_Pool_With_Subpools
)
85 return not null Subpool_Handle
is abstract;
86 -- This routine requires implementation. Create a subpool within the given
87 -- pool_with_subpools.
89 overriding
procedure Deallocate
90 (Pool
: in out Root_Storage_Pool_With_Subpools
;
91 Storage_Address
: System
.Address
;
92 Size_In_Storage_Elements
: System
.Storage_Elements
.Storage_Count
;
93 Alignment
: System
.Storage_Elements
.Storage_Count
)
96 procedure Deallocate_Subpool
97 (Pool
: in out Root_Storage_Pool_With_Subpools
;
98 Subpool
: in out Subpool_Handle
)
100 -- This precondition causes errors in simple tests, disabled for now???
101 -- with Pre'Class => Pool_Of_Subpool (Subpool) = Pool'Access;
103 -- This routine requires implementation. Reclaim the storage a particular
104 -- subpool occupies in a pool_with_subpools. This routine is called by
105 -- Ada.Unchecked_Deallocate_Subpool.
107 function Default_Subpool_For_Pool
108 (Pool
: in out Root_Storage_Pool_With_Subpools
)
109 return not null Subpool_Handle
;
110 -- Return a common subpool which is used for object allocations without a
111 -- Subpool_Handle_Name in the allocator. The default implementation of this
112 -- routine raises Program_Error.
114 function Pool_Of_Subpool
115 (Subpool
: not null Subpool_Handle
)
116 return access Root_Storage_Pool_With_Subpools
'Class;
117 -- Return the owner of the subpool
119 procedure Set_Pool_Of_Subpool
120 (Subpool
: not null Subpool_Handle
;
121 To
: in out Root_Storage_Pool_With_Subpools
'Class);
122 -- Set the owner of the subpool. This is intended to be called from
123 -- Create_Subpool or similar subpool constructors. Raises Program_Error
124 -- if the subpool already belongs to a pool.
126 overriding
function Storage_Size
127 (Pool
: Root_Storage_Pool_With_Subpools
)
128 return System
.Storage_Elements
.Storage_Count
130 (System
.Storage_Elements
.Storage_Count
'Last);
134 -- Pool_With_Subpools SP_Node SP_Node SP_Node
135 -- +-->+--------------------+ +-----+ +-----+ +-----+
136 -- | | Subpools -------->| ------->| ------->| ------->
137 -- | +--------------------+ +-----+ +-----+ +-----+
138 -- | |Finalization_Started|<------ |<------- |<------- |<---
139 -- | +--------------------+ +-----+ +-----+ +-----+
140 -- +--- Controller.Encl_Pool| | nul | | + | | + |
141 -- | +--------------------+ +-----+ +--|--+ +--:--+
144 -- | Root_Subpool V |
145 -- | +-------------+ |
146 -- +-------------------------------- Owner | |
147 -- FM_Node FM_Node +-------------+ |
148 -- +-----+ +-----+<-- Master.Objects| |
149 -- <------ |<------ | +-------------+ |
150 -- +-----+ +-----+ | Node -------+
151 -- | ------>| -----> +-------------+
152 -- +-----+ +-----+ : :
157 -- SP_Nodes are created on the heap. FM_Nodes and associated objects are
158 -- created on the pool_with_subpools.
160 type Any_Storage_Pool_With_Subpools_Ptr
161 is access all Root_Storage_Pool_With_Subpools
'Class;
162 for Any_Storage_Pool_With_Subpools_Ptr
'Storage_Size use 0;
164 -- A pool controller is a special controlled object which ensures the
165 -- proper initialization and finalization of the enclosing pool.
167 type Pool_Controller
(Enclosing_Pool
: Any_Storage_Pool_With_Subpools_Ptr
)
168 is new Ada
.Finalization
.Limited_Controlled
with null record;
170 -- Subpool list types. Each pool_with_subpools contains a list of subpools.
171 -- This is an indirect doubly linked list since subpools are not supposed
172 -- to be allocatable by language design.
175 type SP_Node_Ptr
is access all SP_Node
;
177 type SP_Node
is record
178 Prev
: SP_Node_Ptr
:= null;
179 Next
: SP_Node_Ptr
:= null;
180 Subpool
: Subpool_Handle
:= null;
183 -- Root_Storage_Pool_With_Subpools internal structure. The type uses a
184 -- special controller to perform initialization and finalization actions
185 -- on itself. This is necessary because the end user of this package may
186 -- decide to override Initialize and Finalize, thus disabling the desired
189 -- Pool_With_Subpools SP_Node SP_Node SP_Node
190 -- +-->+--------------------+ +-----+ +-----+ +-----+
191 -- | | Subpools -------->| ------->| ------->| ------->
192 -- | +--------------------+ +-----+ +-----+ +-----+
193 -- | |Finalization_Started| : : : : : :
194 -- | +--------------------+
195 -- +--- Controller.Encl_Pool|
196 -- +--------------------+
200 type Root_Storage_Pool_With_Subpools
is abstract
201 new Root_Storage_Pool
with
203 Subpools
: aliased SP_Node
;
204 -- A doubly linked list of subpools
206 Finalization_Started
: Boolean := False;
207 pragma Atomic
(Finalization_Started
);
208 -- A flag which prevents the creation of new subpools while the master
209 -- pool is being finalized. The flag needs to be atomic because it is
210 -- accessed without Lock_Task / Unlock_Task.
212 Controller
: Pool_Controller
213 (Root_Storage_Pool_With_Subpools
'Unchecked_Access);
214 -- A component which ensures that the enclosing pool is initialized and
215 -- finalized at the appropriate places.
218 -- A subpool is an abstraction layer which sits on top of a pool. It
219 -- contains links to all controlled objects allocated on a particular
222 -- Pool_With_Subpools SP_Node SP_Node SP_Node
223 -- +-->+----------------+ +-----+ +-----+ +-----+
224 -- | | Subpools ------>| ------->| ------->| ------->
225 -- | +----------------+ +-----+ +-----+ +-----+
226 -- | : :<------ |<------- |<------- |
227 -- | : : +-----+ +-----+ +-----+
228 -- | |null | | + | | + |
229 -- | +-----+ +--|--+ +--:--+
231 -- | Root_Subpool V |
232 -- | +-------------+ |
233 -- +---------------------------- Owner | |
235 -- .......... Master | |
242 type Root_Subpool
is abstract tagged limited record
243 Owner
: Any_Storage_Pool_With_Subpools_Ptr
:= null;
244 -- A reference to the master pool_with_subpools
246 Master
: aliased System
.Finalization_Masters
.Finalization_Master
;
247 -- A heterogeneous collection of controlled objects
249 Node
: SP_Node_Ptr
:= null;
250 -- A link to the doubly linked list node which contains the subpool.
251 -- This back pointer is used in subpool deallocation.
254 procedure Adjust_Controlled_Dereference
255 (Addr
: in out System
.Address
;
256 Storage_Size
: in out System
.Storage_Elements
.Storage_Count
;
257 Alignment
: System
.Storage_Elements
.Storage_Count
);
258 -- Given the memory attributes of a heap-allocated object that is known to
259 -- be controlled, adjust the address and size of the object to include the
260 -- two hidden pointers inserted by the finalization machinery.
262 -- ??? Once Storage_Pools.Allocate_Any is removed, this should be renamed
265 procedure Allocate_Any_Controlled
266 (Pool
: in out Root_Storage_Pool
'Class;
267 Context_Subpool
: Subpool_Handle
;
268 Context_Master
: Finalization_Masters
.Finalization_Master_Ptr
;
269 Fin_Address
: Finalization_Masters
.Finalize_Address_Ptr
;
270 Addr
: out System
.Address
;
271 Storage_Size
: System
.Storage_Elements
.Storage_Count
;
272 Alignment
: System
.Storage_Elements
.Storage_Count
;
273 Is_Controlled
: Boolean;
274 On_Subpool
: Boolean);
275 -- Compiler interface. This version of Allocate handles all possible cases,
276 -- either on a pool or a pool_with_subpools, regardless of the controlled
277 -- status of the allocated object. Parameter usage:
279 -- * Pool - The pool associated with the access type. Pool can be any
280 -- derivation from Root_Storage_Pool, including a pool_with_subpools.
282 -- * Context_Subpool - The subpool handle name of an allocator. If no
283 -- subpool handle is present at the point of allocation, the actual
286 -- * Context_Master - The finalization master associated with the access
287 -- type. If the access type's designated type is not controlled, the
288 -- actual would be null.
290 -- * Fin_Address - TSS routine Finalize_Address of the designated type.
291 -- If the designated type is not controlled, the actual would be null.
293 -- * Addr - The address of the allocated object.
295 -- * Storage_Size - The size of the allocated object.
297 -- * Alignment - The alignment of the allocated object.
299 -- * Is_Controlled - A flag which determines whether the allocated object
300 -- is controlled. When set to True, the machinery generates additional
303 -- * On_Subpool - A flag which determines whether the a subpool handle
304 -- name is present at the point of allocation. This is used for error
307 procedure Deallocate_Any_Controlled
308 (Pool
: in out Root_Storage_Pool
'Class;
309 Addr
: System
.Address
;
310 Storage_Size
: System
.Storage_Elements
.Storage_Count
;
311 Alignment
: System
.Storage_Elements
.Storage_Count
;
312 Is_Controlled
: Boolean);
313 -- Compiler interface. This version of Deallocate handles all possible
314 -- cases, either from a pool or a pool_with_subpools, regardless of the
315 -- controlled status of the deallocated object. Parameter usage:
317 -- * Pool - The pool associated with the access type. Pool can be any
318 -- derivation from Root_Storage_Pool, including a pool_with_subpools.
320 -- * Addr - The address of the allocated object.
322 -- * Storage_Size - The size of the allocated object.
324 -- * Alignment - The alignment of the allocated object.
326 -- * Is_Controlled - A flag which determines whether the allocated object
327 -- is controlled. When set to True, the machinery generates additional
330 procedure Detach
(N
: not null SP_Node_Ptr
);
331 -- Unhook a subpool node from an arbitrary subpool list
333 overriding
procedure Finalize
(Controller
: in out Pool_Controller
);
334 -- Buffer routine, calls Finalize_Pool
336 procedure Finalize_Pool
(Pool
: in out Root_Storage_Pool_With_Subpools
);
337 -- Iterate over all subpools of Pool, detach them one by one and finalize
338 -- their masters. This action first detaches a controlled object from a
339 -- particular master, then invokes its Finalize_Address primitive.
341 function Header_Size_With_Padding
342 (Alignment
: System
.Storage_Elements
.Storage_Count
)
343 return System
.Storage_Elements
.Storage_Count
;
344 -- Given an arbitrary alignment, calculate the size of the header which
345 -- precedes a controlled object as the nearest multiple rounded up of the
348 overriding
procedure Initialize
(Controller
: in out Pool_Controller
);
349 -- Buffer routine, calls Initialize_Pool
351 procedure Initialize_Pool
(Pool
: in out Root_Storage_Pool_With_Subpools
);
352 -- Setup the doubly linked list of subpools
354 procedure Print_Pool
(Pool
: Root_Storage_Pool_With_Subpools
);
355 -- Debug routine, output the contents of a pool_with_subpools
357 procedure Print_Subpool
(Subpool
: Subpool_Handle
);
358 -- Debug routine, output the contents of a subpool
360 end System
.Storage_Pools
.Subpools
;