1 | /* ---------------------------------------------------------------------------- |
2 | Copyright (c) 2018-2021, Microsoft Research, Daan Leijen |
3 | This is free software; you can redistribute it and/or modify it under the |
4 | terms of the MIT license. A copy of the license can be found in the file |
5 | "LICENSE" at the root of this distribution. |
6 | -----------------------------------------------------------------------------*/ |
7 | |
8 | #include "mimalloc.h" |
9 | #include "mimalloc-internal.h" |
10 | |
11 | #include <string.h> // memset |
12 | |
13 | // ------------------------------------------------------ |
14 | // Aligned Allocation |
15 | // ------------------------------------------------------ |
16 | |
17 | // Fallback primitive aligned allocation -- split out for better codegen |
18 | static mi_decl_noinline void* mi_heap_malloc_zero_aligned_at_fallback(mi_heap_t* const heap, const size_t size, const size_t alignment, const size_t offset, const bool zero) mi_attr_noexcept |
19 | { |
20 | mi_assert_internal(size <= PTRDIFF_MAX); |
21 | mi_assert_internal(alignment!=0 && _mi_is_power_of_two(alignment) && alignment <= MI_ALIGNMENT_MAX); |
22 | |
23 | const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)` |
24 | const size_t padsize = size + MI_PADDING_SIZE; |
25 | |
26 | // use regular allocation if it is guaranteed to fit the alignment constraints |
27 | if (offset==0 && alignment<=padsize && padsize<=MI_MAX_ALIGN_GUARANTEE && (padsize&align_mask)==0) { |
28 | void* p = _mi_heap_malloc_zero(heap, size, zero); |
29 | mi_assert_internal(p == NULL || ((uintptr_t)p % alignment) == 0); |
30 | return p; |
31 | } |
32 | |
33 | // otherwise over-allocate |
34 | const size_t oversize = size + alignment - 1; |
35 | void* p = _mi_heap_malloc_zero(heap, oversize, zero); |
36 | if (p == NULL) return NULL; |
37 | |
38 | // .. and align within the allocation |
39 | uintptr_t adjust = alignment - (((uintptr_t)p + offset) & align_mask); |
40 | mi_assert_internal(adjust <= alignment); |
41 | void* aligned_p = (adjust == alignment ? p : (void*)((uintptr_t)p + adjust)); |
42 | if (aligned_p != p) mi_page_set_has_aligned(_mi_ptr_page(p), true); |
43 | mi_assert_internal(((uintptr_t)aligned_p + offset) % alignment == 0); |
44 | mi_assert_internal(p == _mi_page_ptr_unalign(_mi_ptr_segment(aligned_p), _mi_ptr_page(aligned_p), aligned_p)); |
45 | |
46 | #if MI_TRACK_ENABLED |
47 | if (p != aligned_p) { |
48 | mi_track_free(p); |
49 | mi_track_malloc(aligned_p,size,zero); |
50 | } |
51 | else { |
52 | mi_track_resize(aligned_p,oversize,size); |
53 | } |
54 | #endif |
55 | return aligned_p; |
56 | } |
57 | |
58 | // Primitive aligned allocation |
59 | static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t size, const size_t alignment, const size_t offset, const bool zero) mi_attr_noexcept |
60 | { |
61 | // note: we don't require `size > offset`, we just guarantee that the address at offset is aligned regardless of the allocated size. |
62 | mi_assert(alignment > 0); |
63 | if mi_unlikely(alignment==0 || !_mi_is_power_of_two(alignment)) { // require power-of-two (see <https://en.cppreference.com/w/c/memory/aligned_alloc>) |
64 | #if MI_DEBUG > 0 |
65 | _mi_error_message(EOVERFLOW, "aligned allocation requires the alignment to be a power-of-two (size %zu, alignment %zu)\n" , size, alignment); |
66 | #endif |
67 | return NULL; |
68 | } |
69 | if mi_unlikely(alignment > MI_ALIGNMENT_MAX) { // we cannot align at a boundary larger than this (or otherwise we cannot find segment headers) |
70 | #if MI_DEBUG > 0 |
71 | _mi_error_message(EOVERFLOW, "aligned allocation has a maximum alignment of %zu (size %zu, alignment %zu)\n" , MI_ALIGNMENT_MAX, size, alignment); |
72 | #endif |
73 | return NULL; |
74 | } |
75 | if mi_unlikely(size > PTRDIFF_MAX) { // we don't allocate more than PTRDIFF_MAX (see <https://sourceware.org/ml/libc-announce/2019/msg00001.html>) |
76 | #if MI_DEBUG > 0 |
77 | _mi_error_message(EOVERFLOW, "aligned allocation request is too large (size %zu, alignment %zu)\n" , size, alignment); |
78 | #endif |
79 | return NULL; |
80 | } |
81 | const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)` |
82 | const size_t padsize = size + MI_PADDING_SIZE; // note: cannot overflow due to earlier size > PTRDIFF_MAX check |
83 | |
84 | // try first if there happens to be a small block available with just the right alignment |
85 | if mi_likely(padsize <= MI_SMALL_SIZE_MAX) { |
86 | mi_page_t* page = _mi_heap_get_free_small_page(heap, padsize); |
87 | const bool is_aligned = (((uintptr_t)page->free+offset) & align_mask)==0; |
88 | if mi_likely(page->free != NULL && is_aligned) |
89 | { |
90 | #if MI_STAT>1 |
91 | mi_heap_stat_increase(heap, malloc, size); |
92 | #endif |
93 | void* p = _mi_page_malloc(heap, page, padsize, zero); // TODO: inline _mi_page_malloc |
94 | mi_assert_internal(p != NULL); |
95 | mi_assert_internal(((uintptr_t)p + offset) % alignment == 0); |
96 | mi_track_malloc(p,size,zero); |
97 | return p; |
98 | } |
99 | } |
100 | // fallback |
101 | return mi_heap_malloc_zero_aligned_at_fallback(heap, size, alignment, offset, zero); |
102 | } |
103 | |
104 | |
105 | // ------------------------------------------------------ |
106 | // Optimized mi_heap_malloc_aligned / mi_malloc_aligned |
107 | // ------------------------------------------------------ |
108 | |
109 | mi_decl_nodiscard mi_decl_restrict void* mi_heap_malloc_aligned_at(mi_heap_t* heap, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
110 | return mi_heap_malloc_zero_aligned_at(heap, size, alignment, offset, false); |
111 | } |
112 | |
113 | mi_decl_nodiscard mi_decl_restrict void* mi_heap_malloc_aligned(mi_heap_t* heap, size_t size, size_t alignment) mi_attr_noexcept { |
114 | #if !MI_PADDING |
115 | // without padding, any small sized allocation is naturally aligned (see also `_mi_segment_page_start`) |
116 | if (!_mi_is_power_of_two(alignment)) return NULL; |
117 | if mi_likely(_mi_is_power_of_two(size) && size >= alignment && size <= MI_SMALL_SIZE_MAX) |
118 | #else |
119 | // with padding, we can only guarantee this for fixed alignments |
120 | if mi_likely((alignment == sizeof(void*) || (alignment == MI_MAX_ALIGN_SIZE && size > (MI_MAX_ALIGN_SIZE/2))) |
121 | && size <= MI_SMALL_SIZE_MAX) |
122 | #endif |
123 | { |
124 | // fast path for common alignment and size |
125 | return mi_heap_malloc_small(heap, size); |
126 | } |
127 | else { |
128 | return mi_heap_malloc_aligned_at(heap, size, alignment, 0); |
129 | } |
130 | } |
131 | |
132 | // ------------------------------------------------------ |
133 | // Aligned Allocation |
134 | // ------------------------------------------------------ |
135 | |
136 | mi_decl_nodiscard mi_decl_restrict void* mi_heap_zalloc_aligned_at(mi_heap_t* heap, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
137 | return mi_heap_malloc_zero_aligned_at(heap, size, alignment, offset, true); |
138 | } |
139 | |
140 | mi_decl_nodiscard mi_decl_restrict void* mi_heap_zalloc_aligned(mi_heap_t* heap, size_t size, size_t alignment) mi_attr_noexcept { |
141 | return mi_heap_zalloc_aligned_at(heap, size, alignment, 0); |
142 | } |
143 | |
144 | mi_decl_nodiscard mi_decl_restrict void* mi_heap_calloc_aligned_at(mi_heap_t* heap, size_t count, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
145 | size_t total; |
146 | if (mi_count_size_overflow(count, size, &total)) return NULL; |
147 | return mi_heap_zalloc_aligned_at(heap, total, alignment, offset); |
148 | } |
149 | |
150 | mi_decl_nodiscard mi_decl_restrict void* mi_heap_calloc_aligned(mi_heap_t* heap, size_t count, size_t size, size_t alignment) mi_attr_noexcept { |
151 | return mi_heap_calloc_aligned_at(heap,count,size,alignment,0); |
152 | } |
153 | |
154 | mi_decl_nodiscard mi_decl_restrict void* mi_malloc_aligned_at(size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
155 | return mi_heap_malloc_aligned_at(mi_get_default_heap(), size, alignment, offset); |
156 | } |
157 | |
158 | mi_decl_nodiscard mi_decl_restrict void* mi_malloc_aligned(size_t size, size_t alignment) mi_attr_noexcept { |
159 | return mi_heap_malloc_aligned(mi_get_default_heap(), size, alignment); |
160 | } |
161 | |
162 | mi_decl_nodiscard mi_decl_restrict void* mi_zalloc_aligned_at(size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
163 | return mi_heap_zalloc_aligned_at(mi_get_default_heap(), size, alignment, offset); |
164 | } |
165 | |
166 | mi_decl_nodiscard mi_decl_restrict void* mi_zalloc_aligned(size_t size, size_t alignment) mi_attr_noexcept { |
167 | return mi_heap_zalloc_aligned(mi_get_default_heap(), size, alignment); |
168 | } |
169 | |
170 | mi_decl_nodiscard mi_decl_restrict void* mi_calloc_aligned_at(size_t count, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
171 | return mi_heap_calloc_aligned_at(mi_get_default_heap(), count, size, alignment, offset); |
172 | } |
173 | |
174 | mi_decl_nodiscard mi_decl_restrict void* mi_calloc_aligned(size_t count, size_t size, size_t alignment) mi_attr_noexcept { |
175 | return mi_heap_calloc_aligned(mi_get_default_heap(), count, size, alignment); |
176 | } |
177 | |
178 | |
179 | // ------------------------------------------------------ |
180 | // Aligned re-allocation |
181 | // ------------------------------------------------------ |
182 | |
183 | static void* mi_heap_realloc_zero_aligned_at(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, size_t offset, bool zero) mi_attr_noexcept { |
184 | mi_assert(alignment > 0); |
185 | if (alignment <= sizeof(uintptr_t)) return _mi_heap_realloc_zero(heap,p,newsize,zero); |
186 | if (p == NULL) return mi_heap_malloc_zero_aligned_at(heap,newsize,alignment,offset,zero); |
187 | size_t size = mi_usable_size(p); |
188 | if (newsize <= size && newsize >= (size - (size / 2)) |
189 | && (((uintptr_t)p + offset) % alignment) == 0) { |
190 | return p; // reallocation still fits, is aligned and not more than 50% waste |
191 | } |
192 | else { |
193 | void* newp = mi_heap_malloc_aligned_at(heap,newsize,alignment,offset); |
194 | if (newp != NULL) { |
195 | if (zero && newsize > size) { |
196 | const mi_page_t* page = _mi_ptr_page(newp); |
197 | if (page->is_zero) { |
198 | // already zero initialized |
199 | mi_assert_expensive(mi_mem_is_zero(newp,newsize)); |
200 | } |
201 | else { |
202 | // also set last word in the previous allocation to zero to ensure any padding is zero-initialized |
203 | size_t start = (size >= sizeof(intptr_t) ? size - sizeof(intptr_t) : 0); |
204 | memset((uint8_t*)newp + start, 0, newsize - start); |
205 | } |
206 | } |
207 | _mi_memcpy_aligned(newp, p, (newsize > size ? size : newsize)); |
208 | mi_free(p); // only free if successful |
209 | } |
210 | return newp; |
211 | } |
212 | } |
213 | |
214 | static void* mi_heap_realloc_zero_aligned(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, bool zero) mi_attr_noexcept { |
215 | mi_assert(alignment > 0); |
216 | if (alignment <= sizeof(uintptr_t)) return _mi_heap_realloc_zero(heap,p,newsize,zero); |
217 | size_t offset = ((uintptr_t)p % alignment); // use offset of previous allocation (p can be NULL) |
218 | return mi_heap_realloc_zero_aligned_at(heap,p,newsize,alignment,offset,zero); |
219 | } |
220 | |
221 | mi_decl_nodiscard void* mi_heap_realloc_aligned_at(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, size_t offset) mi_attr_noexcept { |
222 | return mi_heap_realloc_zero_aligned_at(heap,p,newsize,alignment,offset,false); |
223 | } |
224 | |
225 | mi_decl_nodiscard void* mi_heap_realloc_aligned(mi_heap_t* heap, void* p, size_t newsize, size_t alignment) mi_attr_noexcept { |
226 | return mi_heap_realloc_zero_aligned(heap,p,newsize,alignment,false); |
227 | } |
228 | |
229 | mi_decl_nodiscard void* mi_heap_rezalloc_aligned_at(mi_heap_t* heap, void* p, size_t newsize, size_t alignment, size_t offset) mi_attr_noexcept { |
230 | return mi_heap_realloc_zero_aligned_at(heap, p, newsize, alignment, offset, true); |
231 | } |
232 | |
233 | mi_decl_nodiscard void* mi_heap_rezalloc_aligned(mi_heap_t* heap, void* p, size_t newsize, size_t alignment) mi_attr_noexcept { |
234 | return mi_heap_realloc_zero_aligned(heap, p, newsize, alignment, true); |
235 | } |
236 | |
237 | mi_decl_nodiscard void* mi_heap_recalloc_aligned_at(mi_heap_t* heap, void* p, size_t newcount, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
238 | size_t total; |
239 | if (mi_count_size_overflow(newcount, size, &total)) return NULL; |
240 | return mi_heap_rezalloc_aligned_at(heap, p, total, alignment, offset); |
241 | } |
242 | |
243 | mi_decl_nodiscard void* mi_heap_recalloc_aligned(mi_heap_t* heap, void* p, size_t newcount, size_t size, size_t alignment) mi_attr_noexcept { |
244 | size_t total; |
245 | if (mi_count_size_overflow(newcount, size, &total)) return NULL; |
246 | return mi_heap_rezalloc_aligned(heap, p, total, alignment); |
247 | } |
248 | |
249 | mi_decl_nodiscard void* mi_realloc_aligned_at(void* p, size_t newsize, size_t alignment, size_t offset) mi_attr_noexcept { |
250 | return mi_heap_realloc_aligned_at(mi_get_default_heap(), p, newsize, alignment, offset); |
251 | } |
252 | |
253 | mi_decl_nodiscard void* mi_realloc_aligned(void* p, size_t newsize, size_t alignment) mi_attr_noexcept { |
254 | return mi_heap_realloc_aligned(mi_get_default_heap(), p, newsize, alignment); |
255 | } |
256 | |
257 | mi_decl_nodiscard void* mi_rezalloc_aligned_at(void* p, size_t newsize, size_t alignment, size_t offset) mi_attr_noexcept { |
258 | return mi_heap_rezalloc_aligned_at(mi_get_default_heap(), p, newsize, alignment, offset); |
259 | } |
260 | |
261 | mi_decl_nodiscard void* mi_rezalloc_aligned(void* p, size_t newsize, size_t alignment) mi_attr_noexcept { |
262 | return mi_heap_rezalloc_aligned(mi_get_default_heap(), p, newsize, alignment); |
263 | } |
264 | |
265 | mi_decl_nodiscard void* mi_recalloc_aligned_at(void* p, size_t newcount, size_t size, size_t alignment, size_t offset) mi_attr_noexcept { |
266 | return mi_heap_recalloc_aligned_at(mi_get_default_heap(), p, newcount, size, alignment, offset); |
267 | } |
268 | |
269 | mi_decl_nodiscard void* mi_recalloc_aligned(void* p, size_t newcount, size_t size, size_t alignment) mi_attr_noexcept { |
270 | return mi_heap_recalloc_aligned(mi_get_default_heap(), p, newcount, size, alignment); |
271 | } |
272 | |
273 | |