|
111
|
1 ------------------------------------------------------------------------------
|
|
|
2 -- --
|
|
|
3 -- GNAT RUN-TIME COMPONENTS --
|
|
|
4 -- --
|
|
|
5 -- S Y S T E M . P O O L _ S I Z E --
|
|
|
6 -- --
|
|
|
7 -- B o d y --
|
|
|
8 -- --
|
|
145
|
9 -- Copyright (C) 1992-2019, Free Software Foundation, Inc. --
|
|
111
|
10 -- --
|
|
|
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 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 -- GNAT was originally developed by the GNAT team at New York University. --
|
|
|
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
|
|
|
29 -- --
|
|
|
30 ------------------------------------------------------------------------------
|
|
|
31
|
|
|
32 with System.Soft_Links;
|
|
|
33
|
|
|
34 with Ada.Unchecked_Conversion;
|
|
|
35
|
|
|
36 package body System.Pool_Size is
|
|
|
37
|
|
|
38 package SSE renames System.Storage_Elements;
|
|
|
39 use type SSE.Storage_Offset;
|
|
|
40
|
|
|
41 -- Even though these storage pools are typically only used by a single
|
|
|
42 -- task, if multiple tasks are declared at the same or a more nested scope
|
|
|
43 -- as the storage pool, there still may be concurrent access. The current
|
|
|
44 -- implementation of Stack_Bounded_Pool always uses a global lock for
|
|
|
45 -- protecting access. This should eventually be replaced by an atomic
|
|
|
46 -- linked list implementation for efficiency reasons.
|
|
|
47
|
|
|
48 package SSL renames System.Soft_Links;
|
|
|
49
|
|
|
50 type Storage_Count_Access is access SSE.Storage_Count;
|
|
|
51 function To_Storage_Count_Access is
|
|
|
52 new Ada.Unchecked_Conversion (Address, Storage_Count_Access);
|
|
|
53
|
|
|
54 SC_Size : constant := SSE.Storage_Count'Object_Size / System.Storage_Unit;
|
|
|
55
|
|
|
56 package Variable_Size_Management is
|
|
|
57
|
|
|
58 -- Embedded pool that manages allocation of variable-size data
|
|
|
59
|
|
|
60 -- This pool is used as soon as the Elmt_Size of the pool object is 0
|
|
|
61
|
|
|
62 -- Allocation is done on the first chunk long enough for the request.
|
|
|
63 -- Deallocation just puts the freed chunk at the beginning of the list.
|
|
|
64
|
|
|
65 procedure Initialize (Pool : in out Stack_Bounded_Pool);
|
|
|
66 procedure Allocate
|
|
|
67 (Pool : in out Stack_Bounded_Pool;
|
|
|
68 Address : out System.Address;
|
|
|
69 Storage_Size : SSE.Storage_Count;
|
|
|
70 Alignment : SSE.Storage_Count);
|
|
|
71
|
|
|
72 procedure Deallocate
|
|
|
73 (Pool : in out Stack_Bounded_Pool;
|
|
|
74 Address : System.Address;
|
|
|
75 Storage_Size : SSE.Storage_Count;
|
|
|
76 Alignment : SSE.Storage_Count);
|
|
|
77 end Variable_Size_Management;
|
|
|
78
|
|
|
79 package Vsize renames Variable_Size_Management;
|
|
|
80
|
|
|
81 --------------
|
|
|
82 -- Allocate --
|
|
|
83 --------------
|
|
|
84
|
|
|
85 procedure Allocate
|
|
|
86 (Pool : in out Stack_Bounded_Pool;
|
|
|
87 Address : out System.Address;
|
|
|
88 Storage_Size : SSE.Storage_Count;
|
|
|
89 Alignment : SSE.Storage_Count)
|
|
|
90 is
|
|
|
91 begin
|
|
|
92 SSL.Lock_Task.all;
|
|
|
93
|
|
|
94 if Pool.Elmt_Size = 0 then
|
|
|
95 Vsize.Allocate (Pool, Address, Storage_Size, Alignment);
|
|
|
96
|
|
|
97 elsif Pool.First_Free /= 0 then
|
|
|
98 Address := Pool.The_Pool (Pool.First_Free)'Address;
|
|
|
99 Pool.First_Free := To_Storage_Count_Access (Address).all;
|
|
|
100
|
|
|
101 elsif
|
|
|
102 Pool.First_Empty <= (Pool.Pool_Size - Pool.Aligned_Elmt_Size + 1)
|
|
|
103 then
|
|
|
104 Address := Pool.The_Pool (Pool.First_Empty)'Address;
|
|
|
105 Pool.First_Empty := Pool.First_Empty + Pool.Aligned_Elmt_Size;
|
|
|
106
|
|
|
107 else
|
|
|
108 raise Storage_Error;
|
|
|
109 end if;
|
|
|
110
|
|
|
111 SSL.Unlock_Task.all;
|
|
|
112
|
|
|
113 exception
|
|
|
114 when others =>
|
|
|
115 SSL.Unlock_Task.all;
|
|
|
116 raise;
|
|
|
117 end Allocate;
|
|
|
118
|
|
|
119 ----------------
|
|
|
120 -- Deallocate --
|
|
|
121 ----------------
|
|
|
122
|
|
|
123 procedure Deallocate
|
|
|
124 (Pool : in out Stack_Bounded_Pool;
|
|
|
125 Address : System.Address;
|
|
|
126 Storage_Size : SSE.Storage_Count;
|
|
|
127 Alignment : SSE.Storage_Count)
|
|
|
128 is
|
|
|
129 begin
|
|
|
130 SSL.Lock_Task.all;
|
|
|
131
|
|
|
132 if Pool.Elmt_Size = 0 then
|
|
|
133 Vsize.Deallocate (Pool, Address, Storage_Size, Alignment);
|
|
|
134
|
|
|
135 else
|
|
|
136 To_Storage_Count_Access (Address).all := Pool.First_Free;
|
|
|
137 Pool.First_Free := Address - Pool.The_Pool'Address + 1;
|
|
|
138 end if;
|
|
|
139
|
|
|
140 SSL.Unlock_Task.all;
|
|
|
141 exception
|
|
|
142 when others =>
|
|
|
143 SSL.Unlock_Task.all;
|
|
|
144 raise;
|
|
|
145 end Deallocate;
|
|
|
146
|
|
|
147 ----------------
|
|
|
148 -- Initialize --
|
|
|
149 ----------------
|
|
|
150
|
|
|
151 procedure Initialize (Pool : in out Stack_Bounded_Pool) is
|
|
|
152
|
|
|
153 -- Define the appropriate alignment for allocations. This is the
|
|
|
154 -- maximum of the requested alignment, and the alignment required
|
|
|
155 -- for Storage_Count values. The latter test is to ensure that we
|
|
|
156 -- can properly reference the linked list pointers for free lists.
|
|
|
157
|
|
|
158 Align : constant SSE.Storage_Count :=
|
|
|
159 SSE.Storage_Count'Max
|
|
|
160 (SSE.Storage_Count'Alignment, Pool.Alignment);
|
|
|
161
|
|
|
162 begin
|
|
|
163 if Pool.Elmt_Size = 0 then
|
|
|
164 Vsize.Initialize (Pool);
|
|
|
165
|
|
|
166 else
|
|
|
167 Pool.First_Free := 0;
|
|
|
168 Pool.First_Empty := 1;
|
|
|
169
|
|
|
170 -- Compute the size to allocate given the size of the element and
|
|
|
171 -- the possible alignment requirement as defined above.
|
|
|
172
|
|
|
173 Pool.Aligned_Elmt_Size :=
|
|
|
174 SSE.Storage_Count'Max (SC_Size,
|
|
|
175 ((Pool.Elmt_Size + Align - 1) / Align) * Align);
|
|
|
176 end if;
|
|
|
177 end Initialize;
|
|
|
178
|
|
|
179 ------------------
|
|
|
180 -- Storage_Size --
|
|
|
181 ------------------
|
|
|
182
|
|
|
183 function Storage_Size
|
|
|
184 (Pool : Stack_Bounded_Pool) return SSE.Storage_Count
|
|
|
185 is
|
|
|
186 begin
|
|
|
187 return Pool.Pool_Size;
|
|
|
188 end Storage_Size;
|
|
|
189
|
|
|
190 ------------------------------
|
|
|
191 -- Variable_Size_Management --
|
|
|
192 ------------------------------
|
|
|
193
|
|
|
194 package body Variable_Size_Management is
|
|
|
195
|
|
|
196 Minimum_Size : constant := 2 * SC_Size;
|
|
|
197
|
|
|
198 procedure Set_Size
|
|
|
199 (Pool : Stack_Bounded_Pool;
|
|
|
200 Chunk, Size : SSE.Storage_Count);
|
|
|
201 -- Update the field 'size' of a chunk of available storage
|
|
|
202
|
|
|
203 procedure Set_Next
|
|
|
204 (Pool : Stack_Bounded_Pool;
|
|
|
205 Chunk, Next : SSE.Storage_Count);
|
|
|
206 -- Update the field 'next' of a chunk of available storage
|
|
|
207
|
|
|
208 function Size
|
|
|
209 (Pool : Stack_Bounded_Pool;
|
|
|
210 Chunk : SSE.Storage_Count) return SSE.Storage_Count;
|
|
|
211 -- Fetch the field 'size' of a chunk of available storage
|
|
|
212
|
|
|
213 function Next
|
|
|
214 (Pool : Stack_Bounded_Pool;
|
|
|
215 Chunk : SSE.Storage_Count) return SSE.Storage_Count;
|
|
|
216 -- Fetch the field 'next' of a chunk of available storage
|
|
|
217
|
|
|
218 function Chunk_Of
|
|
|
219 (Pool : Stack_Bounded_Pool;
|
|
|
220 Addr : System.Address) return SSE.Storage_Count;
|
|
|
221 -- Give the chunk number in the pool from its Address
|
|
|
222
|
|
|
223 --------------
|
|
|
224 -- Allocate --
|
|
|
225 --------------
|
|
|
226
|
|
|
227 procedure Allocate
|
|
|
228 (Pool : in out Stack_Bounded_Pool;
|
|
|
229 Address : out System.Address;
|
|
|
230 Storage_Size : SSE.Storage_Count;
|
|
|
231 Alignment : SSE.Storage_Count)
|
|
|
232 is
|
|
|
233 Chunk : SSE.Storage_Count;
|
|
|
234 New_Chunk : SSE.Storage_Count;
|
|
|
235 Prev_Chunk : SSE.Storage_Count;
|
|
|
236 Our_Align : constant SSE.Storage_Count :=
|
|
|
237 SSE.Storage_Count'Max (SSE.Storage_Count'Alignment,
|
|
|
238 Alignment);
|
|
|
239 Align_Size : constant SSE.Storage_Count :=
|
|
|
240 SSE.Storage_Count'Max (
|
|
|
241 Minimum_Size,
|
|
|
242 ((Storage_Size + Our_Align - 1) / Our_Align) *
|
|
|
243 Our_Align);
|
|
|
244
|
|
|
245 begin
|
|
|
246 -- Look for the first big enough chunk
|
|
|
247
|
|
|
248 Prev_Chunk := Pool.First_Free;
|
|
|
249 Chunk := Next (Pool, Prev_Chunk);
|
|
|
250
|
|
|
251 while Chunk /= 0 and then Size (Pool, Chunk) < Align_Size loop
|
|
|
252 Prev_Chunk := Chunk;
|
|
|
253 Chunk := Next (Pool, Chunk);
|
|
|
254 end loop;
|
|
|
255
|
|
|
256 -- Raise storage_error if no big enough chunk available
|
|
|
257
|
|
|
258 if Chunk = 0 then
|
|
|
259 raise Storage_Error;
|
|
|
260 end if;
|
|
|
261
|
|
|
262 -- When the chunk is bigger than what is needed, take appropriate
|
|
|
263 -- amount and build a new shrinked chunk with the remainder.
|
|
|
264
|
|
|
265 if Size (Pool, Chunk) - Align_Size > Minimum_Size then
|
|
|
266 New_Chunk := Chunk + Align_Size;
|
|
|
267 Set_Size (Pool, New_Chunk, Size (Pool, Chunk) - Align_Size);
|
|
|
268 Set_Next (Pool, New_Chunk, Next (Pool, Chunk));
|
|
|
269 Set_Next (Pool, Prev_Chunk, New_Chunk);
|
|
|
270
|
|
|
271 -- If the chunk is the right size, just delete it from the chain
|
|
|
272
|
|
|
273 else
|
|
|
274 Set_Next (Pool, Prev_Chunk, Next (Pool, Chunk));
|
|
|
275 end if;
|
|
|
276
|
|
|
277 Address := Pool.The_Pool (Chunk)'Address;
|
|
|
278 end Allocate;
|
|
|
279
|
|
|
280 --------------
|
|
|
281 -- Chunk_Of --
|
|
|
282 --------------
|
|
|
283
|
|
|
284 function Chunk_Of
|
|
|
285 (Pool : Stack_Bounded_Pool;
|
|
|
286 Addr : System.Address) return SSE.Storage_Count
|
|
|
287 is
|
|
|
288 begin
|
|
|
289 return 1 + abs (Addr - Pool.The_Pool (1)'Address);
|
|
|
290 end Chunk_Of;
|
|
|
291
|
|
|
292 ----------------
|
|
|
293 -- Deallocate --
|
|
|
294 ----------------
|
|
|
295
|
|
|
296 procedure Deallocate
|
|
|
297 (Pool : in out Stack_Bounded_Pool;
|
|
|
298 Address : System.Address;
|
|
|
299 Storage_Size : SSE.Storage_Count;
|
|
|
300 Alignment : SSE.Storage_Count)
|
|
|
301 is
|
|
|
302 pragma Warnings (Off, Pool);
|
|
|
303
|
|
|
304 Align_Size : constant SSE.Storage_Count :=
|
|
|
305 ((Storage_Size + Alignment - 1) / Alignment) *
|
|
|
306 Alignment;
|
|
|
307 Chunk : constant SSE.Storage_Count := Chunk_Of (Pool, Address);
|
|
|
308
|
|
|
309 begin
|
|
|
310 -- Attach the freed chunk to the chain
|
|
|
311
|
|
|
312 Set_Size (Pool, Chunk,
|
|
|
313 SSE.Storage_Count'Max (Align_Size, Minimum_Size));
|
|
|
314 Set_Next (Pool, Chunk, Next (Pool, Pool.First_Free));
|
|
|
315 Set_Next (Pool, Pool.First_Free, Chunk);
|
|
|
316
|
|
|
317 end Deallocate;
|
|
|
318
|
|
|
319 ----------------
|
|
|
320 -- Initialize --
|
|
|
321 ----------------
|
|
|
322
|
|
|
323 procedure Initialize (Pool : in out Stack_Bounded_Pool) is
|
|
|
324 begin
|
|
|
325 Pool.First_Free := 1;
|
|
|
326
|
|
|
327 if Pool.Pool_Size > Minimum_Size then
|
|
|
328 Set_Next (Pool, Pool.First_Free, Pool.First_Free + Minimum_Size);
|
|
|
329 Set_Size (Pool, Pool.First_Free, 0);
|
|
|
330 Set_Size (Pool, Pool.First_Free + Minimum_Size,
|
|
|
331 Pool.Pool_Size - Minimum_Size);
|
|
|
332 Set_Next (Pool, Pool.First_Free + Minimum_Size, 0);
|
|
|
333 end if;
|
|
|
334 end Initialize;
|
|
|
335
|
|
|
336 ----------
|
|
|
337 -- Next --
|
|
|
338 ----------
|
|
|
339
|
|
|
340 function Next
|
|
|
341 (Pool : Stack_Bounded_Pool;
|
|
|
342 Chunk : SSE.Storage_Count) return SSE.Storage_Count
|
|
|
343 is
|
|
|
344 begin
|
|
|
345 pragma Warnings (Off);
|
|
|
346 -- Kill alignment warnings, we are careful to make sure
|
|
|
347 -- that the alignment is correct.
|
|
|
348
|
|
|
349 return To_Storage_Count_Access
|
|
|
350 (Pool.The_Pool (Chunk + SC_Size)'Address).all;
|
|
|
351
|
|
|
352 pragma Warnings (On);
|
|
|
353 end Next;
|
|
|
354
|
|
|
355 --------------
|
|
|
356 -- Set_Next --
|
|
|
357 --------------
|
|
|
358
|
|
|
359 procedure Set_Next
|
|
|
360 (Pool : Stack_Bounded_Pool;
|
|
|
361 Chunk, Next : SSE.Storage_Count)
|
|
|
362 is
|
|
|
363 begin
|
|
|
364 pragma Warnings (Off);
|
|
|
365 -- Kill alignment warnings, we are careful to make sure
|
|
|
366 -- that the alignment is correct.
|
|
|
367
|
|
|
368 To_Storage_Count_Access
|
|
|
369 (Pool.The_Pool (Chunk + SC_Size)'Address).all := Next;
|
|
|
370
|
|
|
371 pragma Warnings (On);
|
|
|
372 end Set_Next;
|
|
|
373
|
|
|
374 --------------
|
|
|
375 -- Set_Size --
|
|
|
376 --------------
|
|
|
377
|
|
|
378 procedure Set_Size
|
|
|
379 (Pool : Stack_Bounded_Pool;
|
|
|
380 Chunk, Size : SSE.Storage_Count)
|
|
|
381 is
|
|
|
382 begin
|
|
|
383 pragma Warnings (Off);
|
|
|
384 -- Kill alignment warnings, we are careful to make sure
|
|
|
385 -- that the alignment is correct.
|
|
|
386
|
|
|
387 To_Storage_Count_Access
|
|
|
388 (Pool.The_Pool (Chunk)'Address).all := Size;
|
|
|
389
|
|
|
390 pragma Warnings (On);
|
|
|
391 end Set_Size;
|
|
|
392
|
|
|
393 ----------
|
|
|
394 -- Size --
|
|
|
395 ----------
|
|
|
396
|
|
|
397 function Size
|
|
|
398 (Pool : Stack_Bounded_Pool;
|
|
|
399 Chunk : SSE.Storage_Count) return SSE.Storage_Count
|
|
|
400 is
|
|
|
401 begin
|
|
|
402 pragma Warnings (Off);
|
|
|
403 -- Kill alignment warnings, we are careful to make sure
|
|
|
404 -- that the alignment is correct.
|
|
|
405
|
|
|
406 return To_Storage_Count_Access (Pool.The_Pool (Chunk)'Address).all;
|
|
|
407
|
|
|
408 pragma Warnings (On);
|
|
|
409 end Size;
|
|
|
410
|
|
|
411 end Variable_Size_Management;
|
|
|
412 end System.Pool_Size;
|
