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Added copy of druntime from DMD 2.020 modified for LDC.
author Tomas Lindquist Olsen <tomas.l.olsen@gmail.com>
date Tue, 11 Nov 2008 01:52:37 +0100
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758:f04dde6e882c 759:d3eb054172f9
1 /**
2 * The memory module provides an interface to the garbage collector and to
3 * any other OS or API-level memory management facilities.
4 *
5 * Copyright: Copyright (c) 2005-2008, The D Runtime Project
6 * License: BSD Style, see LICENSE
7 * Authors: Sean Kelly
8 */
9 module core.memory;
10
11
12 private
13 {
14 extern (C) void gc_init();
15 extern (C) void gc_term();
16
17 extern (C) void gc_enable();
18 extern (C) void gc_disable();
19 extern (C) void gc_collect();
20 extern (C) void gc_minimize();
21
22 extern (C) uint gc_getAttr( void* p );
23 extern (C) uint gc_setAttr( void* p, uint a );
24 extern (C) uint gc_clrAttr( void* p, uint a );
25
26 extern (C) void* gc_malloc( size_t sz, uint ba = 0 );
27 extern (C) void* gc_calloc( size_t sz, uint ba = 0 );
28 extern (C) void* gc_realloc( void* p, size_t sz, uint ba = 0 );
29 extern (C) size_t gc_extend( void* p, size_t mx, size_t sz );
30 extern (C) size_t gc_reserve( size_t sz );
31 extern (C) void gc_free( void* p );
32
33 extern (C) void* gc_addrOf( void* p );
34 extern (C) size_t gc_sizeOf( void* p );
35
36 struct BlkInfo_
37 {
38 void* base;
39 size_t size;
40 uint attr;
41 }
42
43 extern (C) BlkInfo_ gc_query( void* p );
44
45 extern (C) void gc_addRoot( void* p );
46 extern (C) void gc_addRange( void* p, size_t sz );
47
48 extern (C) void gc_removeRoot( void* p );
49 extern (C) void gc_removeRange( void* p );
50
51 extern (C) void* gc_getHandle();
52 extern (C) void gc_setHandle( void* p );
53 extern (C) void gc_endHandle();
54 }
55
56
57 /**
58 * This struct encapsulates all garbage collection functionality for the D
59 * programming language.
60 */
61 struct GC
62 {
63 /**
64 * Enables the garbage collector if collections have previously been
65 * suspended by a call to disable. This function is reentrant, and
66 * must be called once for every call to disable before the garbage
67 * collector is enabled.
68 */
69 static void enable()
70 {
71 gc_enable();
72 }
73
74
75 /**
76 * Disables the garbage collector. This function is reentrant, but
77 * enable must be called once for each call to disable.
78 */
79 static void disable()
80 {
81 gc_disable();
82 }
83
84
85 /**
86 * Begins a full collection. While the meaning of this may change based
87 * on the garbage collector implementation, typical behavior is to scan
88 * all stack segments for roots, mark accessible memory blocks as alive,
89 * and then to reclaim free space. This action may need to suspend all
90 * running threads for at least part of the collection process.
91 */
92 static void collect()
93 {
94 gc_collect();
95 }
96
97 /**
98 * Indicates that the managed memory space be minimized by returning free
99 * physical memory to the operating system. The amount of free memory
100 * returned depends on the allocator design and on program behavior.
101 */
102 static void minimize()
103 {
104 gc_minimize();
105 }
106
107
108 /**
109 * Elements for a bit field representing memory block attributes. These
110 * are manipulated via the getAttr, setAttr, clrAttr functions.
111 */
112 enum BlkAttr : uint
113 {
114 FINALIZE = 0b0000_0001, /// Finalize the data in this block on collect.
115 NO_SCAN = 0b0000_0010, /// Do not scan through this block on collect.
116 NO_MOVE = 0b0000_0100 /// Do not move this memory block on collect.
117 }
118
119
120 /**
121 * Contains aggregate information about a block of managed memory. The
122 * purpose of this struct is to support a more efficient query style in
123 * instances where detailed information is needed.
124 *
125 * base = A pointer to the base of the block in question.
126 * size = The size of the block, calculated from base.
127 * attr = Attribute bits set on the memory block.
128 */
129 alias BlkInfo_ BlkInfo;
130
131
132 /**
133 * Returns a bit field representing all block attributes set for the memory
134 * referenced by p. If p references memory not originally allocated by
135 * this garbage collector, points to the interior of a memory block, or if
136 * p is null, zero will be returned.
137 *
138 * Params:
139 * p = A pointer to the root of a valid memory block or to null.
140 *
141 * Returns:
142 * A bit field containing any bits set for the memory block referenced by
143 * p or zero on error.
144 */
145 static uint getAttr( void* p )
146 {
147 return gc_getAttr( p );
148 }
149
150
151 /**
152 * Sets the specified bits for the memory references by p. If p references
153 * memory not originally allocated by this garbage collector, points to the
154 * interior of a memory block, or if p is null, no action will be
155 * performed.
156 *
157 * Params:
158 * p = A pointer to the root of a valid memory block or to null.
159 * a = A bit field containing any bits to set for this memory block.
160 *
161 * The result of a call to getAttr after the specified bits have been
162 * set.
163 */
164 static uint setAttr( void* p, uint a )
165 {
166 return gc_setAttr( p, a );
167 }
168
169
170 /**
171 * Clears the specified bits for the memory references by p. If p
172 * references memory not originally allocated by this garbage collector,
173 * points to the interior of a memory block, or if p is null, no action
174 * will be performed.
175 *
176 * Params:
177 * p = A pointer to the root of a valid memory block or to null.
178 * a = A bit field containing any bits to clear for this memory block.
179 *
180 * Returns:
181 * The result of a call to getAttr after the specified bits have been
182 * cleared.
183 */
184 static uint clrAttr( void* p, uint a )
185 {
186 return gc_clrAttr( p, a );
187 }
188
189
190 /**
191 * Requests an aligned block of managed memory from the garbage collector.
192 * This memory may be deleted at will with a call to free, or it may be
193 * discarded and cleaned up automatically during a collection run. If
194 * allocation fails, this function will call onOutOfMemory which is
195 * expected to throw an OutOfMemoryException.
196 *
197 * Params:
198 * sz = The desired allocation size in bytes.
199 * ba = A bitmask of the attributes to set on this block.
200 *
201 * Returns:
202 * A reference to the allocated memory or null if insufficient memory
203 * is available.
204 *
205 * Throws:
206 * OutOfMemoryException on allocation failure.
207 */
208 static void* malloc( size_t sz, uint ba = 0 )
209 {
210 return gc_malloc( sz, ba );
211 }
212
213
214 /**
215 * Requests an aligned block of managed memory from the garbage collector,
216 * which is initialized with all bits set to zero. This memory may be
217 * deleted at will with a call to free, or it may be discarded and cleaned
218 * up automatically during a collection run. If allocation fails, this
219 * function will call onOutOfMemory which is expected to throw an
220 * OutOfMemoryException.
221 *
222 * Params:
223 * sz = The desired allocation size in bytes.
224 * ba = A bitmask of the attributes to set on this block.
225 *
226 * Returns:
227 * A reference to the allocated memory or null if insufficient memory
228 * is available.
229 *
230 * Throws:
231 * OutOfMemoryException on allocation failure.
232 */
233 static void* calloc( size_t sz, uint ba = 0 )
234 {
235 return gc_calloc( sz, ba );
236 }
237
238
239 /**
240 * If sz is zero, the memory referenced by p will be deallocated as if
241 * by a call to free. A new memory block of size sz will then be
242 * allocated as if by a call to malloc, or the implementation may instead
243 * resize the memory block in place. The contents of the new memory block
244 * will be the same as the contents of the old memory block, up to the
245 * lesser of the new and old sizes. Note that existing memory will only
246 * be freed by realloc if sz is equal to zero. The garbage collector is
247 * otherwise expected to later reclaim the memory block if it is unused.
248 * If allocation fails, this function will call onOutOfMemory which is
249 * expected to throw an OutOfMemoryException. If p references memory not
250 * originally allocated by this garbage collector, or if it points to the
251 * interior of a memory block, no action will be taken. If ba is zero
252 * (the default) and p references the head of a valid, known memory block
253 * then any bits set on the current block will be set on the new block if a
254 * reallocation is required. If ba is not zero and p references the head
255 * of a valid, known memory block then the bits in ba will replace those on
256 * the current memory block and will also be set on the new block if a
257 * reallocation is required.
258 *
259 * Params:
260 * p = A pointer to the root of a valid memory block or to null.
261 * sz = The desired allocation size in bytes.
262 * ba = A bitmask of the attributes to set on this block.
263 *
264 * Returns:
265 * A reference to the allocated memory on success or null if sz is
266 * zero. On failure, the original value of p is returned.
267 *
268 * Throws:
269 * OutOfMemoryException on allocation failure.
270 */
271 static void* realloc( void* p, size_t sz, uint ba = 0 )
272 {
273 return gc_realloc( p, sz, ba );
274 }
275
276
277 /**
278 * Requests that the managed memory block referenced by p be extended in
279 * place by at least mx bytes, with a desired extension of sz bytes. If an
280 * extension of the required size is not possible, if p references memory
281 * not originally allocated by this garbage collector, or if p points to
282 * the interior of a memory block, no action will be taken.
283 *
284 * Params:
285 * mx = The minimum extension size in bytes.
286 * sz = The desired extension size in bytes.
287 *
288 * Returns:
289 * The size in bytes of the extended memory block referenced by p or zero
290 * if no extension occurred.
291 */
292 static size_t extend( void* p, size_t mx, size_t sz )
293 {
294 return gc_extend( p, mx, sz );
295 }
296
297
298 /**
299 * Requests that at least sz bytes of memory be obtained from the operating
300 * system and marked as free.
301 *
302 * Params:
303 * sz = The desired size in bytes.
304 *
305 * Returns:
306 * The actual number of bytes reserved or zero on error.
307 */
308 static size_t reserve( size_t sz )
309 {
310 return gc_reserve( sz );
311 }
312
313
314 /**
315 * Deallocates the memory referenced by p. If p is null, no action
316 * occurs. If p references memory not originally allocated by this
317 * garbage collector, or if it points to the interior of a memory block,
318 * no action will be taken. The block will not be finalized regardless
319 * of whether the FINALIZE attribute is set. If finalization is desired,
320 * use delete instead.
321 *
322 * Params:
323 * p = A pointer to the root of a valid memory block or to null.
324 */
325 static void free( void* p )
326 {
327 gc_free( p );
328 }
329
330
331 /**
332 * Returns the base address of the memory block containing p. This value
333 * is useful to determine whether p is an interior pointer, and the result
334 * may be passed to routines such as sizeOf which may otherwise fail. If p
335 * references memory not originally allocated by this garbage collector, if
336 * p is null, or if the garbage collector does not support this operation,
337 * null will be returned.
338 *
339 * Params:
340 * p = A pointer to the root or the interior of a valid memory block or to
341 * null.
342 *
343 * Returns:
344 * The base address of the memory block referenced by p or null on error.
345 */
346 static void* addrOf( void* p )
347 {
348 return gc_addrOf( p );
349 }
350
351
352 /**
353 * Returns the true size of the memory block referenced by p. This value
354 * represents the maximum number of bytes for which a call to realloc may
355 * resize the existing block in place. If p references memory not
356 * originally allocated by this garbage collector, points to the interior
357 * of a memory block, or if p is null, zero will be returned.
358 *
359 * Params:
360 * p = A pointer to the root of a valid memory block or to null.
361 *
362 * Returns:
363 * The size in bytes of the memory block referenced by p or zero on error.
364 */
365 static size_t sizeOf( void* p )
366 {
367 return gc_sizeOf( p );
368 }
369
370
371 /**
372 * Returns aggregate information about the memory block containing p. If p
373 * references memory not originally allocated by this garbage collector, if
374 * p is null, or if the garbage collector does not support this operation,
375 * BlkInfo.init will be returned. Typically, support for this operation
376 * is dependent on support for addrOf.
377 *
378 * Params:
379 * p = A pointer to the root or the interior of a valid memory block or to
380 * null.
381 *
382 * Returns:
383 * Information regarding the memory block referenced by p or BlkInfo.init
384 * on error.
385 */
386 static BlkInfo query( void* p )
387 {
388 return gc_query( p );
389 }
390
391
392 /**
393 * Adds the memory address referenced by p to an internal list of roots to
394 * be scanned during a collection. If p is null, no operation is
395 * performed.
396 *
397 * Params:
398 * p = A pointer to a valid memory address or to null.
399 */
400 static void addRoot( void* p )
401 {
402 gc_addRoot( p );
403 }
404
405
406 /**
407 * Adds the memory block referenced by p and of size sz to an internal list
408 * of ranges to be scanned during a collection. If p is null, no operation
409 * is performed.
410 *
411 * Params:
412 * p = A pointer to a valid memory address or to null.
413 * sz = The size in bytes of the block to add. If sz is zero then the
414 * no operation will occur. If p is null then sz must be zero.
415 */
416 static void addRange( void* p, size_t sz )
417 {
418 gc_addRange( p, sz );
419 }
420
421
422 /**
423 * Removes the memory block referenced by p from an internal list of roots
424 * to be scanned during a collection. If p is null or does not represent
425 * a value previously passed to add(void*) then no operation is performed.
426 *
427 * p = A pointer to a valid memory address or to null.
428 */
429 static void removeRoot( void* p )
430 {
431 gc_removeRoot( p );
432 }
433
434
435 /**
436 * Removes the memory block referenced by p from an internal list of ranges
437 * to be scanned during a collection. If p is null or does not represent
438 * a value previously passed to add(void*, size_t) then no operation is
439 * performed.
440 *
441 * Params:
442 * p = A pointer to a valid memory address or to null.
443 */
444 static void removeRange( void* p )
445 {
446 gc_removeRange( p );
447 }
448
449 /**
450 * Get handle to the collector.
451 * The only thing that can be done with this handle is pass it to
452 * setHandle(). getHandle/setHandle/endHandle work together so that
453 * if there are multiple instances of the gc running, only one instance
454 * can be set to run.
455 * The most common case of this is under Windows where a D application
456 * calls functions in a DLL that is implemented in D.
457 */
458
459 static void* getHandle()
460 {
461 return gc_getHandle();
462 }
463
464 /**
465 * Set handle to the collector.
466 * The handle p is an opaque handle, acquired by a call to
467 * getHandle().
468 */
469
470 static void setHandle(void* p)
471 {
472 gc_setHandle(p);
473 }
474
475 /**
476 * Call when done using the collector specified by the
477 * call to setHandle().
478 */
479
480 static void endHandle()
481 {
482 gc_endHandle();
483 }
484 }