Repository navigation
Expand file tree
/
Copy pathallocators.odin
More file actions
2535 lines (2273 loc) · 78 KB
/
Copy pathallocators.odin
File metadata and controls
2535 lines (2273 loc) · 78 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
package mem
import "base:intrinsics"
import "base:runtime"
// NOTE(Feoramund): Sanitizer usage in this package has been temporarily
// disabled pending a thorough review per allocator, as ASan is particular
// about the addresses and ranges it receives.
//
// In short, it keeps track only of 8-byte blocks. This can cause issues if an
// allocator poisons an entire range but an allocation for less than 8 bytes is
// desired or if the next allocation address would not be 8-byte aligned.
//
// This must be handled carefully on a per-allocator basis and some allocators
// may not be able to participate.
//
// Please see the following link for more information:
//
// https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm#mapping
//
// import "base:sanitizer"
/*
This procedure checks if a byte slice `range` is poisoned and makes sure th
8000
e
root address of the poison range is the base pointer of `range`.
This can help guard against buggy allocators returning memory that they already returned.
This has no effect if `-sanitize:address` is not enabled.
*/
// @(disabled=.Address not_in ODIN_SANITIZER_FLAGS, private)
// ensure_poisoned :: proc(range: []u8, loc := #caller_location) {
// cond := sanitizer.address_region_is_poisoned(range) == raw_data(range)
// // If this fails, we've overlapped an allocation and it's our fault.
// ensure(cond, `This allocator has sliced a block of memory of which some part is not poisoned before returning.
// This is a bug in the core library and should be reported to the Odin developers with a stack trace and minimal example code if possible.`, loc)
// }
/*
This procedure checks if a byte slice `range` is not poisoned.
This can help guard against buggy allocators resizing memory that they should not.
This has no effect if `-sanitize:address` is not enabled.
*/
// @(disabled=.Address not_in ODIN_SANITIZER_FLAGS, private)
// ensure_not_poisoned :: proc(range: []u8, loc := #caller_location) {
// cond := sanitizer.address_region_is_poisoned(range) == nil
// // If this fails, we've tried to resize memory that is poisoned, which
// // could be user error caused by an incorrect `old_memory` pointer.
// ensure(cond, `This allocator has sliced a block of memory of which some part is poisoned before returning.
// This may be a bug in the core library, or it could be user error due to an invalid pointer passed to a resize operation.
// If after ensuring your own code is not responsible, report the problem to the Odin developers with a stack trace and minimal example code if possible.`, loc)
// }
/*
Nil allocator.
The `nil` allocator returns `nil` on every allocation attempt. This type of
allocator can be used in scenarios where memory doesn't need to be allocated,
but an attempt to allocate memory is not an error.
*/
@(require_results)
nil_allocator :: proc() -> Allocator {
return Allocator{
procedure = nil_allocator_proc,
data = nil,
}
}
nil_allocator_proc :: proc(
allocator_data: rawptr,
mode: Allocator_Mode,
size, alignment: int,
old_memory: rawptr,
old_size: int,
loc := #caller_location,
) -> ([]byte, Allocator_Error) {
return nil, nil
}
/*
Panic allocator.
The panic allocator is a type of allocator that panics on any allocation
attempt. This type of allocator can be used in scenarios where memory should
not be allocated, and an attempt to allocate memory is an error.
*/
@(require_results)
panic_allocator :: proc() -> Allocator {
return Allocator{
procedure = panic_allocator_proc,
data = nil,
}
}
panic_allocator_proc :: proc(
allocator_data: rawptr,
mode: Allocator_Mode,
size, alignment: int,
old_memory: rawptr,
old_size: int,
loc := #caller_location,
) -> ([]byte, Allocator_Error) {
switch mode {
case .Alloc:
if size > 0 {
panic("mem: panic allocator, .Alloc called", loc=loc)
}
case .Alloc_Non_Zeroed:
if size > 0 {
panic("mem: panic allocator, .Alloc_Non_Zeroed called", loc=loc)
}
case .Resize:
if size > 0 {
panic("mem: panic allocator, .Resize called", loc=loc)
}
case .Resize_Non_Zeroed:
if size > 0 {
panic("mem: panic allocator, .Resize_Non_Zeroed called", loc=loc)
}
case .Free:
if old_memory != nil {
panic("mem: panic allocator, .Free called", loc=loc)
}
case .Free_All:
panic("mem: panic allocator, .Free_All called", loc=loc)
case .Query_Features:
set := (^Allocator_Mode_Set)(old_memory)
if set != nil {
set^ = {.Query_Features}
}
return nil, nil
case .Query_Info:
panic("mem: panic allocator, .Query_Info called", loc=loc)
}
return nil, nil
}
/*
Arena allocator data.
*/
Arena :: struct {
data: []byte,
offset: int,
peak_used: int,
temp_count: int,
}
/*
Arena allocator.
The arena allocator (also known as a linear allocator, bump allocator,
region allocator) is an allocator that uses a single backing buffer for
allocations.
The buffer is used contiguously, from start to end. Each subsequent allocation
occupies the next adjacent region of memory in the buffer. Since the arena
allocator does not keep track of any metadata associated with the allocations
and their locations, it is impossible to free individual allocations.
The arena allocator can be used for temporary allocations in frame-based memory
management. Games are one example of such applications. A global arena can be
used for any temporary memory allocations, and at the end of each frame all
temporary allocations are freed. Since no temporary object is going to live
longer than a frame, no lifetimes are violated.
*/
@(require_results)
arena_allocator :: proc(arena: ^Arena) -> Allocator {
return Allocator{
procedure = arena_allocator_proc,
data = arena,
}
}
/*
Initialize an arena.
This procedure initializes the arena `a` with memory region `data` as its
backing buffer.
*/
arena_init :: proc(a: ^Arena, data: []byte) {
a.data = data
a.offset = 0
a.peak_used = 0
a.temp_count = 0
// sanitizer.address_poison(a.data)
}
/*
Allocate memory from an arena.
This procedure allocates `size` bytes of memory aligned on a boundary specified
by `alignment` from an arena `a`. The allocated memory is zero-initialized.
This procedure returns a pointer to the newly allocated memory region.
*/
@(require_results)
arena_alloc :: proc(
a: ^Arena,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location,
) -> (rawptr, Allocator_Error) {
bytes, err := arena_alloc_bytes(a, size, alignment, loc)
return raw_data(bytes), err
}
/*
Allocate memory from an arena.
This procedure allocates `size` bytes of memory aligned on a boundary specified
by `alignment` from an arena `a`. The allocated memory is zero-initialized.
This procedure returns a slice of the newly allocated memory region.
*/
@(require_results)
arena_alloc_bytes :: proc(
a: ^Arena,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location,
) -> ([]byte, Allocator_Error) {
bytes, err := arena_alloc_bytes_non_zeroed(a, size, alignment, loc)
if bytes != nil {
zero_slice(bytes)
}
return bytes, err
}
/*
Allocate non-initialized memory from an arena.
This procedure allocates `size` bytes of memory aligned on a boundary specified
by `alignment` from an arena `a`. The allocated memory is not explicitly
zero-initialized. This procedure returns a pointer to the newly allocated
memory region.
*/
@(require_results)
arena_alloc_non_zeroed :: proc(
a: ^Arena,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location,
) -> (rawptr, Allocator_Error) {
bytes, err := arena_alloc_bytes_non_zeroed(a, size, alignment, loc)
return raw_data(bytes), err
}
/*
Allocate non-initialized memory from an arena.
This procedure allocates `size` bytes of memory aligned on a boundary specified
by `alignment` from an arena `a`. The allocated memory is not explicitly
zero-initialized. This procedure returns a slice of the newly allocated
memory region.
*/
@(require_results)
arena_alloc_bytes_non_zeroed :: proc(
a: ^Arena,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location
) -> ([]byte, Allocator_Error) {
if a.data == nil {
panic("Allocation on uninitialized Arena allocator.", loc)
}
#no_bounds_check end := &a.data[a.offset]
ptr := align_forward(end, uintptr(alignment))
total_size := size + ptr_sub((^byte)(ptr), (^byte)(end))
if a.offset + total_size > len(a.data) {
return nil, .Out_Of_Memory
}
a.offset += total_size
a.peak_used = max(a.peak_used, a.offset)
result := byte_slice(ptr, size)
// ensure_poisoned(result)
// sanitizer.address_unpoison(result)
return result, nil
}
/*
Free all memory back to the arena allocator.
*/
arena_free_all :: proc(a: ^Arena) {
a.offset = 0
// sanitizer.address_poison(a.data)
}
arena_allocator_proc :: proc(
allocator_data: rawptr,
mode: Allocator_Mode,
size: int,
alignment: int,
old_memory: rawptr,
old_size: int,
loc := #caller_location,
) -> ([]byte, Allocator_Error) {
arena := cast(^Arena)allocator_data
switch mode {
case .Alloc:
return arena_alloc_bytes(arena, size, alignment, loc)
case .Alloc_Non_Zeroed:
return arena_alloc_bytes_non_zeroed(arena, size, alignment, loc)
case .Free:
return nil, .Mode_Not_Implemented
case .Free_All:
arena_free_all(arena)
case .Resize:
return default_resize_bytes_align(byte_slice(old_memory, old_size), size, alignment, arena_allocator(arena), loc)
case .Resize_Non_Zeroed:
return default_resize_bytes_align_non_zeroed(byte_slice(old_memory, old_size), size, alignment, arena_allocator(arena), loc)
case .Query_Features:
set := (^Allocator_Mode_Set)(old_memory)
if set != nil {
set^ = {.Alloc, .Alloc_Non_Zeroed, .Free_All, .Resize, .Resize_Non_Zeroed, .Query_Features}
}
return nil, nil
case .Query_Info:
return nil, .Mode_Not_Implemented
}
return nil, nil
}
/*
Temporary memory region of an `Arena` allocator.
Temporary memory regions of an arena act as "save-points" for the allocator.
When one is created, the subsequent allocations are done inside the temporary
memory region. When `end_arena_temp_memory` is called, the arena is rolled
back, and all of the memory that was allocated from the arena will be freed.
Multiple temporary memory regions can exist at the same time for an arena.
*/
Arena_Temp_Memory :: struct {
arena: ^Arena,
prev_offset: int,
}
/*
Start a temporary memory region.
This procedure creates a temporary memory region. After a temporary memory
region is created, all allocations are said to be *inside* the temporary memory
region, until `end_arena_temp_memory` is called.
*/
@(require_results)
begin_arena_temp_memory :: proc(a: ^Arena) -> Arena_Temp_Memory {
tmp: Arena_Temp_Memory
tmp.arena = a
tmp.prev_offset = a.offset
a.temp_count += 1
return tmp
}
/*
End a temporary memory region.
This procedure ends the temporary memory region for an arena. All of the
allocations *inside* the temporary memory region will be freed to the arena.
*/
end_arena_temp_memory :: proc(tmp: Arena_Temp_Memory) {
assert(tmp.arena.offset >= tmp.prev_offset)
assert(tmp.arena.temp_count > 0)
// sanitizer.address_poison(tmp.arena.data[tmp.prev_offset:tmp.arena.offset])
tmp.arena.offset = tmp.prev_offset
tmp.arena.temp_count -= 1
}
/* Preserved for compatibility */
Scratch_Allocator :: Scratch
scratch_allocator_init :: scratch_init
scratch_allocator_destroy :: scratch_destroy
/*
Scratch allocator data.
*/
Scratch :: struct {
data: []byte,
curr_offset: int,
prev_allocation: rawptr,
prev_allocation_root: rawptr,
backup_allocator: Allocator,
leaked_allocations: [dynamic][]byte,
}
/*
Scratch allocator.
The scratch allocator works in a similar way to the `Arena` allocator. The
scratch allocator has a backing buffer that is allocated in contiguous regions,
from start to end.
Each subsequent allocation will be the next adjacent region of memory in the
backing buffer. If the allocation doesn't fit into the remaining space of the
backing buffer, this allocation is put at the start of the buffer, and all
previous allocations will become invalidated.
If the allocation doesn't fit into the backing buffer as a whole, it will be
allocated using a backing allocator, and the pointer to the allocated memory
region will be put into the `leaked_allocations` array. A `Warning`-level log
message will be sent as well.
Allocations which are resized will be resized in-place if they were the last
allocation. Otherwise, they are re-allocated to avoid overwriting previous
allocations.
The `leaked_allocations` array is managed by the `context` allocator if no
`backup_allocator` is specified in `scratch_init`.
*/
@(require_results)
scratch_allocator :: proc(allocator: ^Scratch) -> Allocator {
return Allocator{
procedure = scratch_allocator_proc,
data = allocator,
}
}
/*
Initialize a scratch allocator.
*/
scratch_init :: proc(s: ^Scratch, size: int, backup_allocator := context.allocator) -> Allocator_Error {
s.data = make_aligned([]byte, size, 2*align_of(rawptr), backup_allocator) or_return
s.curr_offset = 0
s.prev_allocation = nil
s.prev_allocation_root = nil
s.backup_allocator = backup_allocator
s.leaked_allocations.allocator = backup_allocator
// sanitizer.address_poison(s.data)
return nil
}
/*
Free all data associated with a scratch allocator.
This is distinct from `scratch_free_all` in that it deallocates all memory used
to setup the allocator, as opposed to all allocations made from that space.
*/
scratch_destroy :: proc(s: ^Scratch) {
if s == nil {
return
}
for ptr in s.leaked_allocations {
free_bytes(ptr, s.backup_allocator)
}
delete(s.leaked_allocations)
// sanitizer.address_unpoison(s.data)
delete(s.data, s.backup_allocator)
s^ = {}
}
/*
Allocate memory from a scratch allocator.
This procedure allocates `size` bytes of memory aligned on a boundary specified
by `alignment`. The allocated memory region is zero-initialized. This procedure
returns a pointer to the allocated memory region.
*/
@(require_results)
scratch_alloc :: proc(
s: ^Scratch,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location,
) -> (rawptr, Allocator_Error) {
bytes, err := scratch_alloc_bytes(s, size, alignment, loc)
return raw_data(bytes), err
}
/*
Allocate memory from a scratch allocator.
This procedure allocates `size` bytes of memory aligned on a boundary specified
by `alignment`. The allocated memory region is zero-initialized. This procedure
returns a slice of the allocated memory region.
*/
@(require_results)
scratch_alloc_bytes :: proc(
s: ^Scratch,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location,
) -> ([]byte, Allocator_Error) {
bytes, err := scratch_alloc_bytes_non_zeroed(s, size, alignment, loc)
if bytes != nil {
zero_slice(bytes)
}
return bytes, err
}
/*
Allocate non-initialized memory from a scratch allocator.
This procedure allocates `size` bytes of memory aligned on a boundary specified
by `alignment`. The allocated memory region is not explicitly zero-initialized.
This procedure returns a pointer to the allocated memory region.
*/
@(require_results)
scratch_alloc_non_zeroed :: proc(
s: ^Scratch,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location,
) -> (rawptr, Allocator_Error) {
bytes, err := scratch_alloc_bytes_non_zeroed(s, size, alignment, loc)
return raw_data(bytes), err
}
/*
Allocate non-initialized memory from a scratch allocator.
This procedure allocates `size` bytes of memory aligned on a boundary specified
by `alignment`. The allocated memory region is not explicitly zero-initialized.
This procedure returns a slice of the allocated memory region.
*/
@(require_results)
scratch_alloc_bytes_non_zeroed :: proc(
s: ^Scratch,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location,
) -> ([]byte, Allocator_Error) {
if s.data == nil {
DEFAULT_BACKING_SIZE :: 4 * Megabyte
if !(context.allocator.procedure != scratch_allocator_proc && context.allocator.data != s) {
panic("Cyclic initialization of the scratch allocator with itself.", loc)
}
scratch_init(s, DEFAULT_BACKING_SIZE)
}
aligned_size := size
if alignment > 1 {
// It is possible to do this with less bytes, but this is the
// mathematically simpler solution, and this being a Scratch allocator,
// we don't need to be so strict about every byte.
aligned_size += alignment - 1
}
if aligned_size <= len(s.data) {
offset := uintptr(0)
if s.curr_offset+aligned_size <= len(s.data) {
offset = uintptr(s.curr_offset)
} else {
// The allocation will cause an overflow past the boundary of the
// space available, so reset to the starting offset.
offset = 0
}
start := uintptr(raw_data(s.data))
ptr := rawptr(offset+start)
// We keep track of the original base pointer without extra alignment
// in order to later allow the free operation to work from that point.
s.prev_allocation_root = ptr
if !is_aligned(ptr, alignment) {
ptr = align_forward(ptr, uintptr(alignment))
}
s.prev_allocation = ptr
s.curr_offset = int(offset) + aligned_size
result := byte_slice(ptr, size)
// ensure_poisoned(result)
// sanitizer.address_unpoison(result)
return result, nil
} else {
// NOTE: No need to use `aligned_size` here, as the backup allocator will handle alignment for us.
a := s.backup_allocator
ptr, err := alloc_bytes_non_zeroed(size, alignment, a, loc)
if err != nil {
return ptr, err
}
append(&s.leaked_allocations, ptr)
if logger := context.logger; logger.lowest_level <= .Warning {
if logger.procedure != nil {
logger.procedure(logger.data, .Warning, "mem.Scratch resorted to backup_allocator" , logger.options, loc)
}
}
return ptr, err
}
}
/*
Free memory back to the scratch allocator.
This procedure frees the memory region allocated at pointer `ptr`.
If `ptr` is not the latest allocation and is not a leaked allocation, this
operation is a no-op.
*/
scratch_free :: proc(s: ^Scratch, ptr: rawptr, loc := #caller_location) -> Allocator_Error {
if s.data == nil {
panic("Free on an uninitialized Scratch allocator.", loc)
}
if ptr == nil {
return nil
}
start := uintptr(raw_data(s.data))
end := start + uintptr(len(s.data))
old_ptr := uintptr(ptr)
if s.prev_allocation == ptr {
s.curr_offset = int(uintptr(s.prev_allocation_root) - start)
// sanitizer.address_poison(s.data[s.curr_offset:])
s.prev_allocation = nil
s.prev_allocation_root = nil
return nil
}
if start <= old_ptr && old_ptr < end {
// NOTE(bill): Cannot free this pointer but it is valid
return nil
}
if len(s.leaked_allocations) != 0 {
for data, i in s.leaked_allocations {
ptr := raw_data(data)
if ptr == ptr {
free_bytes(data, s.backup_allocator, loc)
ordered_remove(&s.leaked_allocations, i, loc)
return nil
}
}
}
return .Invalid_Pointer
}
/*
Free all memory back to the scratch allocator.
*/
scratch_free_all :: proc(s: ^Scratch, loc := #caller_location) {
s.curr_offset = 0
s.prev_allocation = nil
for ptr in s.leaked_allocations {
free_bytes(ptr, s.backup_allocator, loc)
}
clear(&s.leaked_allocations)
// sanitizer.address_poison(s.data)
}
/*
Resize an allocation owned by a scratch allocator.
This procedure resizes a memory region defined by its location `old_memory`
and its size `old_size` to have a size `size` and alignment `alignment`. The
newly allocated memory, if any, is zero-initialized.
If `old_memory` is `nil`, this procedure acts just like `scratch_alloc()`,
allocating a memory region `size` bytes in size, aligned on a boundary specified
by `alignment`.
If `size` is 0, this procedure acts just like `scratch_free()`, freeing the
memory region located at an address specified by `old_memory`.
This procedure returns the pointer to the resized memory region.
*/
@(require_results)
scratch_resize :: proc(
s: ^Scratch,
old_memory: rawptr,
old_size: int,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location
) -> (rawptr, Allocator_Error) {
bytes, err := scratch_resize_bytes(s, byte_slice(old_memory, old_size), size, alignment, loc)
return raw_data(bytes), err
}
/*
Resize an allocation owned by a scratch allocator.
This procedure resizes a memory region specified by `old_data` to have a size
`size` and alignment `alignment`. The newly allocated memory, if any, is
zero-initialized.
If `old_memory` is `nil`, this procedure acts just like `scratch_alloc()`,
allocating a memory region `size` bytes in size, aligned on a boundary specified
by `alignment`.
If `size` is 0, this procedure acts just like `scratch_free()`, freeing the
memory region located at an address specified by `old_memory`.
This procedure returns the slice of the resized memory region.
*/
@(require_results)
scratch_resize_bytes :: proc(
s: ^Scratch,
old_data: []byte,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location
) -> ([]byte, Allocator_Error) {
bytes, err := scratch_resize_bytes_non_zeroed(s, old_data, size, alignment, loc)
if bytes != nil && size > len(old_data) {
zero_slice(bytes[size:])
}
return bytes, err
}
/*
Resize an allocation owned by a scratch allocator, without zero-initialization.
This procedure resizes a memory region defined by its location `old_memory`
and its size `old_size` to have a size `size` and alignment `alignment`. The
newly allocated memory, if any, is not explicitly zero-initialized.
If `old_memory` is `nil`, this procedure acts just like `scratch_alloc()`,
allocating a memory region `size` bytes in size, aligned on a boundary specified
by `alignment`.
If `size` is 0, this procedure acts just like `scratch_free()`, freeing the
memory region located at an address specified by `old_memory`.
This procedure returns the pointer to the resized memory region.
*/
@(require_results)
scratch_resize_non_zeroed :: proc(
s: ^Scratch,
old_memory: rawptr,
old_size: int,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location
) -> (rawptr, Allocator_Error) {
bytes, err := scratch_resize_bytes_non_zeroed(s, byte_slice(old_memory, old_size), size, alignment, loc)
return raw_data(bytes), err
}
/*
Resize an allocation owned by a scratch allocator.
This procedure resizes a memory region specified by `old_data` to have a size
`size` and alignment `alignment`. The newly allocated memory, if any, is not
explicitly zero-initialized.
If `old_memory` is `nil`, this procedure acts just like `scratch_alloc()`,
allocating a memory region `size` bytes in size, aligned on a boundary specified
by `alignment`.
If `size` is 0, this procedure acts just like `scratch_free()`, freeing the
memory region located at an address specified by `old_memory`.
This procedure returns the slice of the resized memory region.
*/
@(require_results)
scratch_resize_bytes_non_zeroed :: proc(
s: ^Scratch,
old_data: []byte,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location
) -> ([]byte, Allocator_Error) {
old_memory := raw_data(old_data)
old_size := len(old_data)
if s.data == nil {
DEFAULT_BACKING_SIZE :: 4 * Megabyte
if !(context.allocator.procedure != scratch_allocator_proc && context.allocator.data != s) {
panic("Cyclic initialization of the scratch allocator with itself.", loc)
}
scratch_init(s, DEFAULT_BACKING_SIZE)
}
begin := uintptr(raw_data(s.data))
end := begin + uintptr(len(s.data))
old_ptr := uintptr(old_memory)
// We can only sanely resize the last allocation; to do otherwise may
// overwrite memory that could very well just have been allocated.
//
// Also, the alignments must match, otherwise we must re-allocate to
// guarantee the user's request.
if s.prev_allocation == old_memory && is_aligned(old_memory, alignment) && old_ptr+uintptr(size) < end {
// ensure_not_poisoned(old_data)
// sanitizer.address_poison(old_memory)
s.curr_offset = int(old_ptr-begin)+size
result := byte_slice(old_memory, size)
// sanitizer.address_unpoison(result)
return result, nil
}
data, err := scratch_alloc_bytes_non_zeroed(s, size, alignment, loc)
if err != nil {
return data, err
}
runtime.copy(data, byte_slice(old_memory, old_size))
err = scratch_free(s, old_memory, loc)
return data, err
}
scratch_allocator_proc :: proc(
allocator_data: rawptr,
mode: Allocator_Mode,
size, alignment: int,
old_memory: rawptr,
old_size: int,
loc := #caller_location,
) -> ([]byte, Allocator_Error) {
s := (^Scratch)(allocator_data)
size := size
switch mode {
case .Alloc:
return scratch_alloc_bytes(s, size, alignment, loc)
case .Alloc_Non_Zeroed:
return scratch_alloc_bytes_non_zeroed(s, size, alignment, loc)
case .Free:
return nil, scratch_free(s, old_memory, loc)
case .Free_All:
scratch_free_all(s, loc)
case .Resize:
return scratch_resize_bytes(s, byte_slice(old_memory, old_size), size, alignment, loc)
case .Resize_Non_Zeroed:
return scratch_resize_bytes_non_zeroed(s, byte_slice(old_memory, old_size), size, alignment, loc)
case .Query_Features:
set := (^Allocator_Mode_Set)(old_memory)
if set != nil {
set^ = {.Alloc, .Alloc_Non_Zeroed, .Free, .Free_All, .Resize, .Resize_Non_Zeroed, .Query_Features}
}
return nil, nil
case .Query_Info:
return nil, .Mode_Not_Implemented
}
return nil, nil
}
/*
Stack allocator data.
*/
Stack :: struct {
data: []byte,
prev_offset: int,
curr_offset: int,
peak_used: int,
}
/*
Header of a stack allocation.
*/
Stack_Allocation_Header :: struct {
prev_offset: int,
padding: int,
}
/*
Stack allocator.
The stack allocator is an allocator that allocates data in the backing buffer
linearly, from start to end. Each subsequent allocation will get the next
adjacent memory region.
Unlike arena allocator, the stack allocator saves allocation metadata and has
a strict freeing order. Only the last allocated element can be freed. After the
last allocated element is freed, the next previous allocated element becomes
available for freeing.
The metadata is stored in the allocation headers, that are located before the
start of each allocated memory region. Each header points to the start of the
previous allocation header.
*/
@(require_results)
stack_allocator :: proc(stack: ^Stack) -> Allocator {
return Allocator{
procedure = stack_allocator_proc,
data = stack,
}
}
/*
Initialize a stack allocator.
This procedure initializes the stack allocator with a backing buffer specified
by `data` parameter.
*/
stack_init :: proc(s: ^Stack, data: []byte) {
s.data = data
s.prev_offset = 0
s.curr_offset = 0
s.peak_used = 0
// sanitizer.address_poison(data)
}
/*
Allocate memory from a stack allocator.
This procedure allocates `size` bytes of memory, aligned to the boundary
specified by `alignment`. The allocated memory is zero-initialized. This
procedure returns the pointer to the allocated memory.
*/
@(require_results)
stack_alloc :: proc(
s: ^Stack,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location
) -> (rawptr, Allocator_Error) {
bytes, err := stack_alloc_bytes(s, size, alignment, loc)
return raw_data(bytes), err
}
/*
Allocate memory from a stack allocator.
This procedure allocates `size` bytes of memory, aligned to the boundary
specified by `alignment`. The allocated memory is zero-initialized. This
procedure returns the slice of the allocated memory.
*/
@(require_results)
stack_alloc_bytes :: proc(
s: ^Stack,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location
) -> ([]byte, Allocator_Error) {
bytes, err := stack_alloc_bytes_non_zeroed(s, size, alignment, loc)
if bytes != nil {
zero_slice(bytes)
}
return bytes, err
}
/*
Allocate memory from a stack allocator.
This procedure allocates `size` bytes of memory, aligned to the boundary
specified by `alignment`. The allocated memory is not explicitly
zero-initialized. This procedure returns the pointer to the allocated memory.
*/
@(require_results)
stack_alloc_non_zeroed :: proc(
s: ^Stack,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location
) -> (rawptr, Allocator_Error) {
bytes, err := stack_alloc_bytes_non_zeroed(s, size, alignment, loc)
return raw_data(bytes), err
}
/*
Allocate memory from a stack allocator.
This procedure allocates `size` bytes of memory, aligned to the boundary
specified by `alignment`. The allocated memory is not explicitly
zero-initialized. This procedure returns the slice of the allocated memory.
*/
@(require_results, no_sanitize_address)
stack_alloc_bytes_non_zeroed :: proc(
s: ^Stack,
size: int,
alignment := DEFAULT_ALIGNMENT,
loc := #caller_location
) -> ([]byte, Allocator_Error) {
if s.data == nil {
panic("Allocation on an uninitialized Stack allocator.", loc)
}
curr_addr := uintptr(raw_data(s.data)) + uintptr(s.curr_offset)
padding := calc_padding_with_header(
curr_addr,
uintptr(alignment),
size_of(Stack_Allocation_Header),
)
if s.curr_offset + padding + size > len(s.data) {
return nil, .Out_Of_Memory
}
old_offset := s.prev_offset
s.prev_offset = s.curr_offset
s.curr_offset += padding
next_addr := curr_addr + uintptr(padding)
header := (^Stack_Allocation_Header)(next_addr - size_of(Stack_Allocation_Header))
header.padding = padding
header.prev_offset = old_offset
s.curr_offset += size
s.peak_used = max(s.peak_used, s.curr_offset)
result := byte_slice(rawptr(next_addr), size)
// ensure_poisoned(result)
// sanitizer.address_unpoison(result)
return result, nil
}
/*
Free memory back to the stack allocator.
This procedure frees the memory region starting at `old_memory` to the stack.
If the freeing is an out of order freeing, the `.Invalid_Pointer` error
is returned.
*/
stack_free :: proc(
s: ^Stack,
old_memory: rawptr,
loc := #caller_location,
) -> (Allocator_Error) {
if s.data == nil {
panic("Free on an uninitialized Stack allocator.", loc)
}
if old_memory == nil {
return nil
}
start := uintptr(raw_data(s.data))
end := start + uintptr(len(s.data))
curr_addr := uintptr(old_memory)
if !(start <= curr_addr && curr_addr < end) {
panic("Out of bounds memory address passed to Stack allocator. (free)", loc)
}
if curr_addr >= start+uintptr(s.curr_offset) {
// NOTE(bill): Allow double frees
return nil
}
header := (^Stack_Allocation_Header)(curr_addr - size_of(Stack_Allocation_Header))