1 | //===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | // |
9 | // This file defines the SmallVector class. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | // ATen: modified from llvm::SmallVector. |
14 | // used std::is_trivially_{copy,move}_constructible |
15 | // replaced iterator_range constructor with inline Container&& constructor |
16 | // replaced LLVM_NODISCARD, LLVM_LIKELY, and LLVM_UNLIKELY with c10 equivalents |
17 | // removed LLVM_GSL_OWNER |
18 | // added SmallVector::at |
19 | // added operator<< for std::ostream |
20 | // added C10_API to export SmallVectorBase |
21 | |
22 | #pragma once |
23 | |
24 | #include <c10/macros/Macros.h> |
25 | #include <c10/util/AlignOf.h> |
26 | |
27 | #include <algorithm> |
28 | #include <cassert> |
29 | #include <cstddef> |
30 | #include <cstdlib> |
31 | #include <cstring> |
32 | #include <functional> |
33 | #include <initializer_list> |
34 | #include <iterator> |
35 | #include <limits> |
36 | #include <memory> |
37 | #include <new> |
38 | #include <ostream> |
39 | #include <type_traits> |
40 | #include <utility> |
41 | |
42 | C10_CLANG_DIAGNOSTIC_PUSH() |
43 | #if C10_CLANG_HAS_WARNING("-Wshorten-64-to-32") |
44 | C10_CLANG_DIAGNOSTIC_IGNORE("-Wshorten-64-to-32" ) |
45 | #endif |
46 | |
47 | namespace c10 { |
48 | |
49 | /// This is all the stuff common to all SmallVectors. |
50 | /// |
51 | /// The template parameter specifies the type which should be used to hold the |
52 | /// Size and Capacity of the SmallVector, so it can be adjusted. |
53 | /// Using 32 bit size is desirable to shrink the size of the SmallVector. |
54 | /// Using 64 bit size is desirable for cases like SmallVector<char>, where a |
55 | /// 32 bit size would limit the vector to ~4GB. SmallVectors are used for |
56 | /// buffering bitcode output - which can exceed 4GB. |
57 | template <class Size_T> |
58 | class C10_API SmallVectorBase { |
59 | protected: |
60 | void* BeginX; |
61 | Size_T Size = 0, Capacity; |
62 | |
63 | /// The maximum value of the Size_T used. |
64 | static constexpr size_t SizeTypeMax() { |
65 | return std::numeric_limits<Size_T>::max(); |
66 | } |
67 | |
68 | SmallVectorBase(void* FirstEl, size_t TotalCapacity) |
69 | : BeginX(FirstEl), Capacity(TotalCapacity) {} |
70 | |
71 | /// This is a helper for \a grow() that's out of line to reduce code |
72 | /// duplication. This function will report a fatal error if it can't grow at |
73 | /// least to \p MinSize. |
74 | void* mallocForGrow(size_t MinSize, size_t TSize, size_t& NewCapacity); |
75 | |
76 | /// This is an implementation of the grow() method which only works |
77 | /// on POD-like data types and is out of line to reduce code duplication. |
78 | /// This function will report a fatal error if it cannot increase capacity. |
79 | void grow_pod(void* FirstEl, size_t MinSize, size_t TSize); |
80 | |
81 | public: |
82 | SmallVectorBase() = delete; |
83 | size_t size() const { |
84 | return Size; |
85 | } |
86 | size_t capacity() const { |
87 | return Capacity; |
88 | } |
89 | |
90 | C10_NODISCARD bool empty() const { |
91 | return !Size; |
92 | } |
93 | |
94 | /// Set the array size to \p N, which the current array must have enough |
95 | /// capacity for. |
96 | /// |
97 | /// This does not construct or destroy any elements in the vector. |
98 | /// |
99 | /// Clients can use this in conjunction with capacity() to write past the end |
100 | /// of the buffer when they know that more elements are available, and only |
101 | /// update the size later. This avoids the cost of value initializing elements |
102 | /// which will only be overwritten. |
103 | void set_size(size_t N) { |
104 | assert(N <= capacity()); |
105 | Size = N; |
106 | } |
107 | }; |
108 | |
109 | template <class T> |
110 | using SmallVectorSizeType = typename std:: |
111 | conditional<sizeof(T) < 4 && sizeof(void*) >= 8, uint64_t, uint32_t>::type; |
112 | |
113 | /// Figure out the offset of the first element. |
114 | template <class T, typename = void> |
115 | struct SmallVectorAlignmentAndSize { |
116 | alignas(SmallVectorBase<SmallVectorSizeType<T>>) char Base[sizeof( |
117 | SmallVectorBase<SmallVectorSizeType<T>>)]; |
118 | alignas(T) char FirstEl[sizeof(T)]; |
119 | }; |
120 | |
121 | /// This is the part of SmallVectorTemplateBase which does not depend on whether |
122 | /// the type T is a POD. The extra dummy template argument is used by ArrayRef |
123 | /// to avoid unnecessarily requiring T to be complete. |
124 | template <typename T, typename = void> |
125 | class SmallVectorTemplateCommon |
126 | : public SmallVectorBase<SmallVectorSizeType<T>> { |
127 | using Base = SmallVectorBase<SmallVectorSizeType<T>>; |
128 | |
129 | /// Find the address of the first element. For this pointer math to be valid |
130 | /// with small-size of 0 for T with lots of alignment, it's important that |
131 | /// SmallVectorStorage is properly-aligned even for small-size of 0. |
132 | void* getFirstEl() const { |
133 | return const_cast<void*>(reinterpret_cast<const void*>( |
134 | reinterpret_cast<const char*>(this) + |
135 | offsetof(SmallVectorAlignmentAndSize<T>, FirstEl))); |
136 | } |
137 | // Space after 'FirstEl' is clobbered, do not add any instance vars after it. |
138 | |
139 | protected: |
140 | SmallVectorTemplateCommon(size_t Size) : Base(getFirstEl(), Size) {} |
141 | |
142 | void grow_pod(size_t MinSize, size_t TSize) { |
143 | Base::grow_pod(getFirstEl(), MinSize, TSize); |
144 | } |
145 | |
146 | /// Return true if this is a smallvector which has not had dynamic |
147 | /// memory allocated for it. |
148 | bool isSmall() const { |
149 | return this->BeginX == getFirstEl(); |
150 | } |
151 | |
152 | /// Put this vector in a state of being small. |
153 | void resetToSmall() { |
154 | this->BeginX = getFirstEl(); |
155 | this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect. |
156 | } |
157 | |
158 | /// Return true if V is an internal reference to the given range. |
159 | bool isReferenceToRange(const void* V, const void* First, const void* Last) |
160 | const { |
161 | // Use std::less to avoid UB. |
162 | std::less<> LessThan; |
163 | return !LessThan(V, First) && LessThan(V, Last); |
164 | } |
165 | |
166 | /// Return true if V is an internal reference to this vector. |
167 | bool isReferenceToStorage(const void* V) const { |
168 | return isReferenceToRange(V, this->begin(), this->end()); |
169 | } |
170 | |
171 | /// Return true if First and Last form a valid (possibly empty) range in this |
172 | /// vector's storage. |
173 | bool isRangeInStorage(const void* First, const void* Last) const { |
174 | // Use std::less to avoid UB. |
175 | std::less<> LessThan; |
176 | return !LessThan(First, this->begin()) && !LessThan(Last, First) && |
177 | !LessThan(this->end(), Last); |
178 | } |
179 | |
180 | /// Return true unless Elt will be invalidated by resizing the vector to |
181 | /// NewSize. |
182 | bool isSafeToReferenceAfterResize(const void* Elt, size_t NewSize) { |
183 | // Past the end. |
184 | if (C10_LIKELY(!isReferenceToStorage(Elt))) |
185 | return true; |
186 | |
187 | // Return false if Elt will be destroyed by shrinking. |
188 | if (NewSize <= this->size()) |
189 | return Elt < this->begin() + NewSize; |
190 | |
191 | // Return false if we need to grow. |
192 | return NewSize <= this->capacity(); |
193 | } |
194 | |
195 | /// Check whether Elt will be invalidated by resizing the vector to NewSize. |
196 | void assertSafeToReferenceAfterResize(const void* Elt, size_t NewSize) { |
197 | (void)Elt; // Suppress unused variable warning |
198 | (void)NewSize; // Suppress unused variable warning |
199 | assert( |
200 | isSafeToReferenceAfterResize(Elt, NewSize) && |
201 | "Attempting to reference an element of the vector in an operation " |
202 | "that invalidates it" ); |
203 | } |
204 | |
205 | /// Check whether Elt will be invalidated by increasing the size of the |
206 | /// vector by N. |
207 | void assertSafeToAdd(const void* Elt, size_t N = 1) { |
208 | this->assertSafeToReferenceAfterResize(Elt, this->size() + N); |
209 | } |
210 | |
211 | /// Check whether any part of the range will be invalidated by clearing. |
212 | void assertSafeToReferenceAfterClear(const T* From, const T* To) { |
213 | if (From == To) |
214 | return; |
215 | this->assertSafeToReferenceAfterResize(From, 0); |
216 | this->assertSafeToReferenceAfterResize(To - 1, 0); |
217 | } |
218 | template < |
219 | class ItTy, |
220 | std::enable_if_t< |
221 | !std::is_same<std::remove_const_t<ItTy>, T*>::value, |
222 | bool> = false> |
223 | void assertSafeToReferenceAfterClear(ItTy, ItTy) {} |
224 | |
225 | /// Check whether any part of the range will be invalidated by growing. |
226 | void assertSafeToAddRange(const T* From, const T* To) { |
227 | if (From == To) |
228 | return; |
229 | this->assertSafeToAdd(From, To - From); |
230 | this->assertSafeToAdd(To - 1, To - From); |
231 | } |
232 | template < |
233 | class ItTy, |
234 | std::enable_if_t< |
235 | !std::is_same<std::remove_const_t<ItTy>, T*>::value, |
236 | bool> = false> |
237 | void assertSafeToAddRange(ItTy, ItTy) {} |
238 | |
239 | /// Reserve enough space to add one element, and return the updated element |
240 | /// pointer in case it was a reference to the storage. |
241 | template <class U> |
242 | static const T* reserveForParamAndGetAddressImpl( |
243 | U* This, |
244 | const T& Elt, |
245 | size_t N) { |
246 | size_t NewSize = This->size() + N; |
247 | if (C10_LIKELY(NewSize <= This->capacity())) |
248 | return &Elt; |
249 | |
250 | bool ReferencesStorage = false; |
251 | int64_t Index = -1; |
252 | if (!U::TakesParamByValue) { |
253 | if (C10_UNLIKELY(This->isReferenceToStorage(&Elt))) { |
254 | ReferencesStorage = true; |
255 | Index = &Elt - This->begin(); |
256 | } |
257 | } |
258 | This->grow(NewSize); |
259 | return ReferencesStorage ? This->begin() + Index : &Elt; |
260 | } |
261 | |
262 | public: |
263 | using size_type = size_t; |
264 | using difference_type = ptrdiff_t; |
265 | using value_type = T; |
266 | using iterator = T*; |
267 | using const_iterator = const T*; |
268 | |
269 | using const_reverse_iterator = std::reverse_iterator<const_iterator>; |
270 | using reverse_iterator = std::reverse_iterator<iterator>; |
271 | |
272 | using reference = T&; |
273 | using const_reference = const T&; |
274 | using pointer = T*; |
275 | using const_pointer = const T*; |
276 | |
277 | using Base::capacity; |
278 | using Base::empty; |
279 | using Base::size; |
280 | |
281 | // forward iterator creation methods. |
282 | iterator begin() { |
283 | return (iterator)this->BeginX; |
284 | } |
285 | const_iterator begin() const { |
286 | return (const_iterator)this->BeginX; |
287 | } |
288 | iterator end() { |
289 | return begin() + size(); |
290 | } |
291 | const_iterator end() const { |
292 | return begin() + size(); |
293 | } |
294 | |
295 | // reverse iterator creation methods. |
296 | reverse_iterator rbegin() { |
297 | return reverse_iterator(end()); |
298 | } |
299 | const_reverse_iterator rbegin() const { |
300 | return const_reverse_iterator(end()); |
301 | } |
302 | reverse_iterator rend() { |
303 | return reverse_iterator(begin()); |
304 | } |
305 | const_reverse_iterator rend() const { |
306 | return const_reverse_iterator(begin()); |
307 | } |
308 | |
309 | size_type size_in_bytes() const { |
310 | return size() * sizeof(T); |
311 | } |
312 | size_type max_size() const { |
313 | return std::min(this->SizeTypeMax(), size_type(-1) / sizeof(T)); |
314 | } |
315 | |
316 | size_t capacity_in_bytes() const { |
317 | return capacity() * sizeof(T); |
318 | } |
319 | |
320 | /// Return a pointer to the vector's buffer, even if empty(). |
321 | pointer data() { |
322 | return pointer(begin()); |
323 | } |
324 | /// Return a pointer to the vector's buffer, even if empty(). |
325 | const_pointer data() const { |
326 | return const_pointer(begin()); |
327 | } |
328 | |
329 | // SmallVector::at is NOT from LLVM. |
330 | reference at(size_type idx) { |
331 | assert(idx < size()); |
332 | return begin()[idx]; |
333 | } |
334 | const_reference at(size_type idx) const { |
335 | assert(idx < size()); |
336 | return begin()[idx]; |
337 | } |
338 | reference operator[](size_type idx) { |
339 | assert(idx < size()); |
340 | return begin()[idx]; |
341 | } |
342 | const_reference operator[](size_type idx) const { |
343 | assert(idx < size()); |
344 | return begin()[idx]; |
345 | } |
346 | |
347 | reference front() { |
348 | assert(!empty()); |
349 | return begin()[0]; |
350 | } |
351 | const_reference front() const { |
352 | assert(!empty()); |
353 | return begin()[0]; |
354 | } |
355 | |
356 | reference back() { |
357 | assert(!empty()); |
358 | return end()[-1]; |
359 | } |
360 | const_reference back() const { |
361 | assert(!empty()); |
362 | return end()[-1]; |
363 | } |
364 | }; |
365 | |
366 | /// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put |
367 | /// method implementations that are designed to work with non-trivial T's. |
368 | /// |
369 | /// We approximate is_trivially_copyable with trivial move/copy construction and |
370 | /// trivial destruction. While the standard doesn't specify that you're allowed |
371 | /// copy these types with memcpy, there is no way for the type to observe this. |
372 | /// This catches the important case of std::pair<POD, POD>, which is not |
373 | /// trivially assignable. |
374 | /// |
375 | /// XXX: if build fails here fall back to C10_IS_TRIVIALLY_COPYABLE and make a |
376 | /// note |
377 | template < |
378 | typename T, |
379 | bool = (std::is_trivially_copy_constructible<T>::value) && |
380 | (std::is_trivially_move_constructible<T>::value) && |
381 | std::is_trivially_destructible<T>::value> |
382 | class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> { |
383 | friend class SmallVectorTemplateCommon<T>; |
384 | |
385 | protected: |
386 | static constexpr bool TakesParamByValue = false; |
387 | using ValueParamT = const T&; |
388 | |
389 | SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} |
390 | |
391 | static void destroy_range(T* S, T* E) { |
392 | while (S != E) { |
393 | --E; |
394 | E->~T(); |
395 | } |
396 | } |
397 | |
398 | /// Move the range [I, E) into the uninitialized memory starting with "Dest", |
399 | /// constructing elements as needed. |
400 | template <typename It1, typename It2> |
401 | static void uninitialized_move(It1 I, It1 E, It2 Dest) { |
402 | std::uninitialized_copy( |
403 | std::make_move_iterator(I), std::make_move_iterator(E), Dest); |
404 | } |
405 | |
406 | /// Copy the range [I, E) onto the uninitialized memory starting with "Dest", |
407 | /// constructing elements as needed. |
408 | template <typename It1, typename It2> |
409 | static void uninitialized_copy(It1 I, It1 E, It2 Dest) { |
410 | std::uninitialized_copy(I, E, Dest); |
411 | } |
412 | |
413 | /// Grow the allocated memory (without initializing new elements), doubling |
414 | /// the size of the allocated memory. Guarantees space for at least one more |
415 | /// element, or MinSize more elements if specified. |
416 | void grow(size_t MinSize = 0); |
417 | |
418 | /// Create a new allocation big enough for \p MinSize and pass back its size |
419 | /// in \p NewCapacity. This is the first section of \a grow(). |
420 | T* mallocForGrow(size_t MinSize, size_t& NewCapacity) { |
421 | return static_cast<T*>( |
422 | SmallVectorBase<SmallVectorSizeType<T>>::mallocForGrow( |
423 | MinSize, sizeof(T), NewCapacity)); |
424 | } |
425 | |
426 | /// Move existing elements over to the new allocation \p NewElts, the middle |
427 | /// section of \a grow(). |
428 | void moveElementsForGrow(T* NewElts); |
429 | |
430 | /// Transfer ownership of the allocation, finishing up \a grow(). |
431 | void takeAllocationForGrow(T* NewElts, size_t NewCapacity); |
432 | |
433 | /// Reserve enough space to add one element, and return the updated element |
434 | /// pointer in case it was a reference to the storage. |
435 | const T* reserveForParamAndGetAddress(const T& Elt, size_t N = 1) { |
436 | return this->reserveForParamAndGetAddressImpl(this, Elt, N); |
437 | } |
438 | |
439 | /// Reserve enough space to add one element, and return the updated element |
440 | /// pointer in case it was a reference to the storage. |
441 | T* reserveForParamAndGetAddress(T& Elt, size_t N = 1) { |
442 | return const_cast<T*>(this->reserveForParamAndGetAddressImpl(this, Elt, N)); |
443 | } |
444 | |
445 | static T&& forward_value_param(T&& V) { |
446 | return std::move(V); |
447 | } |
448 | static const T& forward_value_param(const T& V) { |
449 | return V; |
450 | } |
451 | |
452 | void growAndAssign(size_t NumElts, const T& Elt) { |
453 | // Grow manually in case Elt is an internal reference. |
454 | size_t NewCapacity = 0; |
455 | T* NewElts = mallocForGrow(NumElts, NewCapacity); |
456 | std::uninitialized_fill_n(NewElts, NumElts, Elt); |
457 | this->destroy_range(this->begin(), this->end()); |
458 | takeAllocationForGrow(NewElts, NewCapacity); |
459 | this->set_size(NumElts); |
460 | } |
461 | |
462 | template <typename... ArgTypes> |
463 | T& growAndEmplaceBack(ArgTypes&&... Args) { |
464 | // Grow manually in case one of Args is an internal reference. |
465 | size_t NewCapacity = 0; |
466 | T* NewElts = mallocForGrow(0, NewCapacity); |
467 | ::new ((void*)(NewElts + this->size())) T(std::forward<ArgTypes>(Args)...); |
468 | moveElementsForGrow(NewElts); |
469 | takeAllocationForGrow(NewElts, NewCapacity); |
470 | this->set_size(this->size() + 1); |
471 | return this->back(); |
472 | } |
473 | |
474 | public: |
475 | void push_back(const T& Elt) { |
476 | const T* EltPtr = reserveForParamAndGetAddress(Elt); |
477 | ::new ((void*)this->end()) T(*EltPtr); |
478 | this->set_size(this->size() + 1); |
479 | } |
480 | |
481 | void push_back(T&& Elt) { |
482 | T* EltPtr = reserveForParamAndGetAddress(Elt); |
483 | ::new ((void*)this->end()) T(::std::move(*EltPtr)); |
484 | this->set_size(this->size() + 1); |
485 | } |
486 | |
487 | void pop_back() { |
488 | this->set_size(this->size() - 1); |
489 | this->end()->~T(); |
490 | } |
491 | }; |
492 | |
493 | // Define this out-of-line to dissuade the C++ compiler from inlining it. |
494 | template <typename T, bool TriviallyCopyable> |
495 | void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) { |
496 | size_t NewCapacity = 0; |
497 | T* NewElts = mallocForGrow(MinSize, NewCapacity); |
498 | moveElementsForGrow(NewElts); |
499 | takeAllocationForGrow(NewElts, NewCapacity); |
500 | } |
501 | |
502 | // Define this out-of-line to dissuade the C++ compiler from inlining it. |
503 | template <typename T, bool TriviallyCopyable> |
504 | void SmallVectorTemplateBase<T, TriviallyCopyable>::moveElementsForGrow( |
505 | T* NewElts) { |
506 | // Move the elements over. |
507 | this->uninitialized_move(this->begin(), this->end(), NewElts); |
508 | |
509 | // Destroy the original elements. |
510 | destroy_range(this->begin(), this->end()); |
511 | } |
512 | |
513 | // Define this out-of-line to dissuade the C++ compiler from inlining it. |
514 | template <typename T, bool TriviallyCopyable> |
515 | void SmallVectorTemplateBase<T, TriviallyCopyable>::takeAllocationForGrow( |
516 | T* NewElts, |
517 | size_t NewCapacity) { |
518 | // If this wasn't grown from the inline copy, deallocate the old space. |
519 | if (!this->isSmall()) |
520 | free(this->begin()); |
521 | |
522 | this->BeginX = NewElts; |
523 | this->Capacity = NewCapacity; |
524 | } |
525 | |
526 | /// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put |
527 | /// method implementations that are designed to work with trivially copyable |
528 | /// T's. This allows using memcpy in place of copy/move construction and |
529 | /// skipping destruction. |
530 | template <typename T> |
531 | class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> { |
532 | friend class SmallVectorTemplateCommon<T>; |
533 | |
534 | protected: |
535 | /// True if it's cheap enough to take parameters by value. Doing so avoids |
536 | /// overhead related to mitigations for reference invalidation. |
537 | static constexpr bool TakesParamByValue = sizeof(T) <= 2 * sizeof(void*); |
538 | |
539 | /// Either const T& or T, depending on whether it's cheap enough to take |
540 | /// parameters by value. |
541 | using ValueParamT = |
542 | typename std::conditional<TakesParamByValue, T, const T&>::type; |
543 | |
544 | SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} |
545 | |
546 | // No need to do a destroy loop for POD's. |
547 | static void destroy_range(T*, T*) {} |
548 | |
549 | /// Move the range [I, E) onto the uninitialized memory |
550 | /// starting with "Dest", constructing elements into it as needed. |
551 | template <typename It1, typename It2> |
552 | static void uninitialized_move(It1 I, It1 E, It2 Dest) { |
553 | // Just do a copy. |
554 | uninitialized_copy(I, E, Dest); |
555 | } |
556 | |
557 | /// Copy the range [I, E) onto the uninitialized memory |
558 | /// starting with "Dest", constructing elements into it as needed. |
559 | template <typename It1, typename It2> |
560 | static void uninitialized_copy(It1 I, It1 E, It2 Dest) { |
561 | // Arbitrary iterator types; just use the basic implementation. |
562 | std::uninitialized_copy(I, E, Dest); |
563 | } |
564 | |
565 | /// Copy the range [I, E) onto the uninitialized memory |
566 | /// starting with "Dest", constructing elements into it as needed. |
567 | template <typename T1, typename T2> |
568 | static void uninitialized_copy( |
569 | T1* I, |
570 | T1* E, |
571 | T2* Dest, |
572 | std::enable_if_t< |
573 | std::is_same<typename std::remove_const<T1>::type, T2>::value>* = |
574 | nullptr) { |
575 | // Use memcpy for PODs iterated by pointers (which includes SmallVector |
576 | // iterators): std::uninitialized_copy optimizes to memmove, but we can |
577 | // use memcpy here. Note that I and E are iterators and thus might be |
578 | // invalid for memcpy if they are equal. |
579 | if (I != E) |
580 | memcpy(reinterpret_cast<void*>(Dest), I, (E - I) * sizeof(T)); |
581 | } |
582 | |
583 | /// Double the size of the allocated memory, guaranteeing space for at |
584 | /// least one more element or MinSize if specified. |
585 | void grow(size_t MinSize = 0) { |
586 | this->grow_pod(MinSize, sizeof(T)); |
587 | } |
588 | |
589 | /// Reserve enough space to add one element, and return the updated element |
590 | /// pointer in case it was a reference to the storage. |
591 | const T* reserveForParamAndGetAddress(const T& Elt, size_t N = 1) { |
592 | return this->reserveForParamAndGetAddressImpl(this, Elt, N); |
593 | } |
594 | |
595 | /// Reserve enough space to add one element, and return the updated element |
596 | /// pointer in case it was a reference to the storage. |
597 | T* reserveForParamAndGetAddress(T& Elt, size_t N = 1) { |
598 | return const_cast<T*>(this->reserveForParamAndGetAddressImpl(this, Elt, N)); |
599 | } |
600 | |
601 | /// Copy \p V or return a reference, depending on \a ValueParamT. |
602 | static ValueParamT forward_value_param(ValueParamT V) { |
603 | return V; |
604 | } |
605 | |
606 | void growAndAssign(size_t NumElts, T Elt) { |
607 | // Elt has been copied in case it's an internal reference, side-stepping |
608 | // reference invalidation problems without losing the realloc optimization. |
609 | this->set_size(0); |
610 | this->grow(NumElts); |
611 | std::uninitialized_fill_n(this->begin(), NumElts, Elt); |
612 | this->set_size(NumElts); |
613 | } |
614 | |
615 | template <typename... ArgTypes> |
616 | T& growAndEmplaceBack(ArgTypes&&... Args) { |
617 | // Use push_back with a copy in case Args has an internal reference, |
618 | // side-stepping reference invalidation problems without losing the realloc |
619 | // optimization. |
620 | push_back(T(std::forward<ArgTypes>(Args)...)); |
621 | return this->back(); |
622 | } |
623 | |
624 | public: |
625 | void push_back(ValueParamT Elt) { |
626 | const T* EltPtr = reserveForParamAndGetAddress(Elt); |
627 | memcpy(reinterpret_cast<void*>(this->end()), EltPtr, sizeof(T)); |
628 | this->set_size(this->size() + 1); |
629 | } |
630 | |
631 | void pop_back() { |
632 | this->set_size(this->size() - 1); |
633 | } |
634 | }; |
635 | |
636 | /// This class consists of common code factored out of the SmallVector class to |
637 | /// reduce code duplication based on the SmallVector 'N' template parameter. |
638 | template <typename T> |
639 | class SmallVectorImpl : public SmallVectorTemplateBase<T> { |
640 | using SuperClass = SmallVectorTemplateBase<T>; |
641 | |
642 | public: |
643 | using iterator = typename SuperClass::iterator; |
644 | using const_iterator = typename SuperClass::const_iterator; |
645 | using reference = typename SuperClass::reference; |
646 | using size_type = typename SuperClass::size_type; |
647 | |
648 | protected: |
649 | using SmallVectorTemplateBase<T>::TakesParamByValue; |
650 | using ValueParamT = typename SuperClass::ValueParamT; |
651 | |
652 | // Default ctor - Initialize to empty. |
653 | explicit SmallVectorImpl(unsigned N) : SmallVectorTemplateBase<T>(N) {} |
654 | |
655 | public: |
656 | SmallVectorImpl(const SmallVectorImpl&) = delete; |
657 | |
658 | ~SmallVectorImpl() { |
659 | // Subclass has already destructed this vector's elements. |
660 | // If this wasn't grown from the inline copy, deallocate the old space. |
661 | if (!this->isSmall()) |
662 | free(this->begin()); |
663 | } |
664 | |
665 | void clear() { |
666 | this->destroy_range(this->begin(), this->end()); |
667 | this->Size = 0; |
668 | } |
669 | |
670 | private: |
671 | template <bool ForOverwrite> |
672 | void resizeImpl(size_type N) { |
673 | if (N < this->size()) { |
674 | this->pop_back_n(this->size() - N); |
675 | } else if (N > this->size()) { |
676 | this->reserve(N); |
677 | for (auto I = this->end(), E = this->begin() + N; I != E; ++I) |
678 | if (ForOverwrite) |
679 | new (&*I) T; |
680 | else |
681 | new (&*I) T(); |
682 | this->set_size(N); |
683 | } |
684 | } |
685 | |
686 | public: |
687 | void resize(size_type N) { |
688 | resizeImpl<false>(N); |
689 | } |
690 | |
691 | /// Like resize, but \ref T is POD, the new values won't be initialized. |
692 | void resize_for_overwrite(size_type N) { |
693 | resizeImpl<true>(N); |
694 | } |
695 | |
696 | void resize(size_type N, ValueParamT NV) { |
697 | if (N == this->size()) |
698 | return; |
699 | |
700 | if (N < this->size()) { |
701 | this->pop_back_n(this->size() - N); |
702 | return; |
703 | } |
704 | |
705 | // N > this->size(). Defer to append. |
706 | this->append(N - this->size(), NV); |
707 | } |
708 | |
709 | void reserve(size_type N) { |
710 | if (this->capacity() < N) |
711 | this->grow(N); |
712 | } |
713 | |
714 | void pop_back_n(size_type NumItems) { |
715 | assert(this->size() >= NumItems); |
716 | this->destroy_range(this->end() - NumItems, this->end()); |
717 | this->set_size(this->size() - NumItems); |
718 | } |
719 | |
720 | C10_NODISCARD T pop_back_val() { |
721 | T Result = ::std::move(this->back()); |
722 | this->pop_back(); |
723 | return Result; |
724 | } |
725 | |
726 | void swap(SmallVectorImpl& RHS); |
727 | |
728 | /// Add the specified range to the end of the SmallVector. |
729 | template < |
730 | typename in_iter, |
731 | typename = std::enable_if_t<std::is_convertible< |
732 | typename std::iterator_traits<in_iter>::iterator_category, |
733 | std::input_iterator_tag>::value>> |
734 | void append(in_iter in_start, in_iter in_end) { |
735 | this->assertSafeToAddRange(in_start, in_end); |
736 | size_type NumInputs = std::distance(in_start, in_end); |
737 | this->reserve(this->size() + NumInputs); |
738 | this->uninitialized_copy(in_start, in_end, this->end()); |
739 | this->set_size(this->size() + NumInputs); |
740 | } |
741 | |
742 | /// Append \p NumInputs copies of \p Elt to the end. |
743 | void append(size_type NumInputs, ValueParamT Elt) { |
744 | const T* EltPtr = this->reserveForParamAndGetAddress(Elt, NumInputs); |
745 | std::uninitialized_fill_n(this->end(), NumInputs, *EltPtr); |
746 | this->set_size(this->size() + NumInputs); |
747 | } |
748 | |
749 | void append(std::initializer_list<T> IL) { |
750 | append(IL.begin(), IL.end()); |
751 | } |
752 | |
753 | void append(const SmallVectorImpl& RHS) { |
754 | append(RHS.begin(), RHS.end()); |
755 | } |
756 | |
757 | void assign(size_type NumElts, ValueParamT Elt) { |
758 | // Note that Elt could be an internal reference. |
759 | if (NumElts > this->capacity()) { |
760 | this->growAndAssign(NumElts, Elt); |
761 | return; |
762 | } |
763 | |
764 | // Assign over existing elements. |
765 | std::fill_n(this->begin(), std::min(NumElts, this->size()), Elt); |
766 | if (NumElts > this->size()) |
767 | std::uninitialized_fill_n(this->end(), NumElts - this->size(), Elt); |
768 | else if (NumElts < this->size()) |
769 | this->destroy_range(this->begin() + NumElts, this->end()); |
770 | this->set_size(NumElts); |
771 | } |
772 | |
773 | // FIXME: Consider assigning over existing elements, rather than clearing & |
774 | // re-initializing them - for all assign(...) variants. |
775 | |
776 | template < |
777 | typename in_iter, |
778 | typename = std::enable_if_t<std::is_convertible< |
779 | typename std::iterator_traits<in_iter>::iterator_category, |
780 | std::input_iterator_tag>::value>> |
781 | void assign(in_iter in_start, in_iter in_end) { |
782 | this->assertSafeToReferenceAfterClear(in_start, in_end); |
783 | clear(); |
784 | append(in_start, in_end); |
785 | } |
786 | |
787 | void assign(std::initializer_list<T> IL) { |
788 | clear(); |
789 | append(IL); |
790 | } |
791 | |
792 | void assign(const SmallVectorImpl& RHS) { |
793 | assign(RHS.begin(), RHS.end()); |
794 | } |
795 | |
796 | iterator erase(const_iterator CI) { |
797 | // Just cast away constness because this is a non-const member function. |
798 | iterator I = const_cast<iterator>(CI); |
799 | |
800 | assert( |
801 | this->isReferenceToStorage(CI) && |
802 | "Iterator to erase is out of bounds." ); |
803 | |
804 | iterator N = I; |
805 | // Shift all elts down one. |
806 | std::move(I + 1, this->end(), I); |
807 | // Drop the last elt. |
808 | this->pop_back(); |
809 | return (N); |
810 | } |
811 | |
812 | iterator erase(const_iterator CS, const_iterator CE) { |
813 | // Just cast away constness because this is a non-const member function. |
814 | iterator S = const_cast<iterator>(CS); |
815 | iterator E = const_cast<iterator>(CE); |
816 | |
817 | assert(this->isRangeInStorage(S, E) && "Range to erase is out of bounds." ); |
818 | |
819 | iterator N = S; |
820 | // Shift all elts down. |
821 | iterator I = std::move(E, this->end(), S); |
822 | // Drop the last elts. |
823 | this->destroy_range(I, this->end()); |
824 | this->set_size(I - this->begin()); |
825 | return (N); |
826 | } |
827 | |
828 | private: |
829 | template <class ArgType> |
830 | iterator insert_one_impl(iterator I, ArgType&& Elt) { |
831 | // Callers ensure that ArgType is derived from T. |
832 | static_assert( |
833 | std::is_same<std::remove_const_t<std::remove_reference_t<ArgType>>, T>:: |
834 | value, |
835 | "ArgType must be derived from T!" ); |
836 | |
837 | if (I == this->end()) { // Important special case for empty vector. |
838 | this->push_back(::std::forward<ArgType>(Elt)); |
839 | return this->end() - 1; |
840 | } |
841 | |
842 | assert( |
843 | this->isReferenceToStorage(I) && |
844 | "Insertion iterator is out of bounds." ); |
845 | |
846 | // Grow if necessary. |
847 | size_t Index = I - this->begin(); |
848 | std::remove_reference_t<ArgType>* EltPtr = |
849 | this->reserveForParamAndGetAddress(Elt); |
850 | I = this->begin() + Index; |
851 | |
852 | ::new ((void*)this->end()) T(::std::move(this->back())); |
853 | // Push everything else over. |
854 | std::move_backward(I, this->end() - 1, this->end()); |
855 | this->set_size(this->size() + 1); |
856 | |
857 | // If we just moved the element we're inserting, be sure to update |
858 | // the reference (never happens if TakesParamByValue). |
859 | static_assert( |
860 | !TakesParamByValue || std::is_same<ArgType, T>::value, |
861 | "ArgType must be 'T' when taking by value!" ); |
862 | if (!TakesParamByValue && this->isReferenceToRange(EltPtr, I, this->end())) |
863 | ++EltPtr; |
864 | |
865 | *I = ::std::forward<ArgType>(*EltPtr); |
866 | return I; |
867 | } |
868 | |
869 | public: |
870 | iterator insert(iterator I, T&& Elt) { |
871 | return insert_one_impl(I, this->forward_value_param(std::move(Elt))); |
872 | } |
873 | |
874 | iterator insert(iterator I, const T& Elt) { |
875 | return insert_one_impl(I, this->forward_value_param(Elt)); |
876 | } |
877 | |
878 | iterator insert(iterator I, size_type NumToInsert, ValueParamT Elt) { |
879 | // Convert iterator to elt# to avoid invalidating iterator when we reserve() |
880 | size_t InsertElt = I - this->begin(); |
881 | |
882 | if (I == this->end()) { // Important special case for empty vector. |
883 | append(NumToInsert, Elt); |
884 | return this->begin() + InsertElt; |
885 | } |
886 | |
887 | assert( |
888 | this->isReferenceToStorage(I) && |
889 | "Insertion iterator is out of bounds." ); |
890 | |
891 | // Ensure there is enough space, and get the (maybe updated) address of |
892 | // Elt. |
893 | const T* EltPtr = this->reserveForParamAndGetAddress(Elt, NumToInsert); |
894 | |
895 | // Uninvalidate the iterator. |
896 | I = this->begin() + InsertElt; |
897 | |
898 | // If there are more elements between the insertion point and the end of the |
899 | // range than there are being inserted, we can use a simple approach to |
900 | // insertion. Since we already reserved space, we know that this won't |
901 | // reallocate the vector. |
902 | if (size_t(this->end() - I) >= NumToInsert) { |
903 | T* OldEnd = this->end(); |
904 | append( |
905 | std::move_iterator<iterator>(this->end() - NumToInsert), |
906 | std::move_iterator<iterator>(this->end())); |
907 | |
908 | // Copy the existing elements that get replaced. |
909 | std::move_backward(I, OldEnd - NumToInsert, OldEnd); |
910 | |
911 | // If we just moved the element we're inserting, be sure to update |
912 | // the reference (never happens if TakesParamByValue). |
913 | if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end()) |
914 | EltPtr += NumToInsert; |
915 | |
916 | std::fill_n(I, NumToInsert, *EltPtr); |
917 | return I; |
918 | } |
919 | |
920 | // Otherwise, we're inserting more elements than exist already, and we're |
921 | // not inserting at the end. |
922 | |
923 | // Move over the elements that we're about to overwrite. |
924 | T* OldEnd = this->end(); |
925 | this->set_size(this->size() + NumToInsert); |
926 | size_t NumOverwritten = OldEnd - I; |
927 | this->uninitialized_move(I, OldEnd, this->end() - NumOverwritten); |
928 | |
929 | // If we just moved the element we're inserting, be sure to update |
930 | // the reference (never happens if TakesParamByValue). |
931 | if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end()) |
932 | EltPtr += NumToInsert; |
933 | |
934 | // Replace the overwritten part. |
935 | std::fill_n(I, NumOverwritten, *EltPtr); |
936 | |
937 | // Insert the non-overwritten middle part. |
938 | std::uninitialized_fill_n(OldEnd, NumToInsert - NumOverwritten, *EltPtr); |
939 | return I; |
940 | } |
941 | |
942 | template < |
943 | typename ItTy, |
944 | typename = std::enable_if_t<std::is_convertible< |
945 | typename std::iterator_traits<ItTy>::iterator_category, |
946 | std::input_iterator_tag>::value>> |
947 | iterator insert(iterator I, ItTy From, ItTy To) { |
948 | // Convert iterator to elt# to avoid invalidating iterator when we reserve() |
949 | size_t InsertElt = I - this->begin(); |
950 | |
951 | if (I == this->end()) { // Important special case for empty vector. |
952 | append(From, To); |
953 | return this->begin() + InsertElt; |
954 | } |
955 | |
956 | assert( |
957 | this->isReferenceToStorage(I) && |
958 | "Insertion iterator is out of bounds." ); |
959 | |
960 | // Check that the reserve that follows doesn't invalidate the iterators. |
961 | this->assertSafeToAddRange(From, To); |
962 | |
963 | size_t NumToInsert = std::distance(From, To); |
964 | |
965 | // Ensure there is enough space. |
966 | reserve(this->size() + NumToInsert); |
967 | |
968 | // Uninvalidate the iterator. |
969 | I = this->begin() + InsertElt; |
970 | |
971 | // If there are more elements between the insertion point and the end of the |
972 | // range than there are being inserted, we can use a simple approach to |
973 | // insertion. Since we already reserved space, we know that this won't |
974 | // reallocate the vector. |
975 | if (size_t(this->end() - I) >= NumToInsert) { |
976 | T* OldEnd = this->end(); |
977 | append( |
978 | std::move_iterator<iterator>(this->end() - NumToInsert), |
979 | std::move_iterator<iterator>(this->end())); |
980 | |
981 | // Copy the existing elements that get replaced. |
982 | std::move_backward(I, OldEnd - NumToInsert, OldEnd); |
983 | |
984 | std::copy(From, To, I); |
985 | return I; |
986 | } |
987 | |
988 | // Otherwise, we're inserting more elements than exist already, and we're |
989 | // not inserting at the end. |
990 | |
991 | // Move over the elements that we're about to overwrite. |
992 | T* OldEnd = this->end(); |
993 | this->set_size(this->size() + NumToInsert); |
994 | size_t NumOverwritten = OldEnd - I; |
995 | this->uninitialized_move(I, OldEnd, this->end() - NumOverwritten); |
996 | |
997 | // Replace the overwritten part. |
998 | for (T* J = I; NumOverwritten > 0; --NumOverwritten) { |
999 | *J = *From; |
1000 | ++J; |
1001 | ++From; |
1002 | } |
1003 | |
1004 | // Insert the non-overwritten middle part. |
1005 | this->uninitialized_copy(From, To, OldEnd); |
1006 | return I; |
1007 | } |
1008 | |
1009 | void insert(iterator I, std::initializer_list<T> IL) { |
1010 | insert(I, IL.begin(), IL.end()); |
1011 | } |
1012 | |
1013 | template <typename... ArgTypes> |
1014 | reference emplace_back(ArgTypes&&... Args) { |
1015 | if (C10_UNLIKELY(this->size() >= this->capacity())) |
1016 | return this->growAndEmplaceBack(std::forward<ArgTypes>(Args)...); |
1017 | |
1018 | ::new ((void*)this->end()) T(std::forward<ArgTypes>(Args)...); |
1019 | this->set_size(this->size() + 1); |
1020 | return this->back(); |
1021 | } |
1022 | |
1023 | SmallVectorImpl& operator=(const SmallVectorImpl& RHS); |
1024 | |
1025 | SmallVectorImpl& operator=(SmallVectorImpl&& RHS); |
1026 | |
1027 | bool operator==(const SmallVectorImpl& RHS) const { |
1028 | if (this->size() != RHS.size()) |
1029 | return false; |
1030 | return std::equal(this->begin(), this->end(), RHS.begin()); |
1031 | } |
1032 | bool operator!=(const SmallVectorImpl& RHS) const { |
1033 | return !(*this == RHS); |
1034 | } |
1035 | |
1036 | bool operator<(const SmallVectorImpl& RHS) const { |
1037 | return std::lexicographical_compare( |
1038 | this->begin(), this->end(), RHS.begin(), RHS.end()); |
1039 | } |
1040 | }; |
1041 | |
1042 | template <typename T> |
1043 | void SmallVectorImpl<T>::swap(SmallVectorImpl<T>& RHS) { |
1044 | if (this == &RHS) |
1045 | return; |
1046 | |
1047 | // We can only avoid copying elements if neither vector is small. |
1048 | if (!this->isSmall() && !RHS.isSmall()) { |
1049 | std::swap(this->BeginX, RHS.BeginX); |
1050 | std::swap(this->Size, RHS.Size); |
1051 | std::swap(this->Capacity, RHS.Capacity); |
1052 | return; |
1053 | } |
1054 | this->reserve(RHS.size()); |
1055 | RHS.reserve(this->size()); |
1056 | |
1057 | // Swap the shared elements. |
1058 | size_t NumShared = this->size(); |
1059 | if (NumShared > RHS.size()) |
1060 | NumShared = RHS.size(); |
1061 | for (size_type i = 0; i != NumShared; ++i) |
1062 | std::swap((*this)[i], RHS[i]); |
1063 | |
1064 | // Copy over the extra elts. |
1065 | if (this->size() > RHS.size()) { |
1066 | size_t EltDiff = this->size() - RHS.size(); |
1067 | this->uninitialized_copy(this->begin() + NumShared, this->end(), RHS.end()); |
1068 | RHS.set_size(RHS.size() + EltDiff); |
1069 | this->destroy_range(this->begin() + NumShared, this->end()); |
1070 | this->set_size(NumShared); |
1071 | } else if (RHS.size() > this->size()) { |
1072 | size_t EltDiff = RHS.size() - this->size(); |
1073 | this->uninitialized_copy(RHS.begin() + NumShared, RHS.end(), this->end()); |
1074 | this->set_size(this->size() + EltDiff); |
1075 | this->destroy_range(RHS.begin() + NumShared, RHS.end()); |
1076 | RHS.set_size(NumShared); |
1077 | } |
1078 | } |
1079 | |
1080 | template <typename T> |
1081 | SmallVectorImpl<T>& SmallVectorImpl<T>::operator=( |
1082 | const SmallVectorImpl<T>& RHS) { |
1083 | // Avoid self-assignment. |
1084 | if (this == &RHS) |
1085 | return *this; |
1086 | |
1087 | // If we already have sufficient space, assign the common elements, then |
1088 | // destroy any excess. |
1089 | size_t RHSSize = RHS.size(); |
1090 | size_t CurSize = this->size(); |
1091 | if (CurSize >= RHSSize) { |
1092 | // Assign common elements. |
1093 | iterator NewEnd; |
1094 | if (RHSSize) |
1095 | NewEnd = std::copy(RHS.begin(), RHS.begin() + RHSSize, this->begin()); |
1096 | else |
1097 | NewEnd = this->begin(); |
1098 | |
1099 | // Destroy excess elements. |
1100 | this->destroy_range(NewEnd, this->end()); |
1101 | |
1102 | // Trim. |
1103 | this->set_size(RHSSize); |
1104 | return *this; |
1105 | } |
1106 | |
1107 | // If we have to grow to have enough elements, destroy the current elements. |
1108 | // This allows us to avoid copying them during the grow. |
1109 | // FIXME: don't do this if they're efficiently moveable. |
1110 | if (this->capacity() < RHSSize) { |
1111 | // Destroy current elements. |
1112 | this->clear(); |
1113 | CurSize = 0; |
1114 | this->grow(RHSSize); |
1115 | } else if (CurSize) { |
1116 | // Otherwise, use assignment for the already-constructed elements. |
1117 | std::copy(RHS.begin(), RHS.begin() + CurSize, this->begin()); |
1118 | } |
1119 | |
1120 | // Copy construct the new elements in place. |
1121 | this->uninitialized_copy( |
1122 | RHS.begin() + CurSize, RHS.end(), this->begin() + CurSize); |
1123 | |
1124 | // Set end. |
1125 | this->set_size(RHSSize); |
1126 | return *this; |
1127 | } |
1128 | |
1129 | template <typename T> |
1130 | SmallVectorImpl<T>& SmallVectorImpl<T>::operator=(SmallVectorImpl<T>&& RHS) { |
1131 | // Avoid self-assignment. |
1132 | if (this == &RHS) |
1133 | return *this; |
1134 | |
1135 | // If the RHS isn't small, clear this vector and then steal its buffer. |
1136 | if (!RHS.isSmall()) { |
1137 | this->destroy_range(this->begin(), this->end()); |
1138 | if (!this->isSmall()) |
1139 | free(this->begin()); |
1140 | this->BeginX = RHS.BeginX; |
1141 | this->Size = RHS.Size; |
1142 | this->Capacity = RHS.Capacity; |
1143 | RHS.resetToSmall(); |
1144 | return *this; |
1145 | } |
1146 | |
1147 | // If we already have sufficient space, assign the common elements, then |
1148 | // destroy any excess. |
1149 | size_t RHSSize = RHS.size(); |
1150 | size_t CurSize = this->size(); |
1151 | if (CurSize >= RHSSize) { |
1152 | // Assign common elements. |
1153 | iterator NewEnd = this->begin(); |
1154 | if (RHSSize) |
1155 | NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd); |
1156 | |
1157 | // Destroy excess elements and trim the bounds. |
1158 | this->destroy_range(NewEnd, this->end()); |
1159 | this->set_size(RHSSize); |
1160 | |
1161 | // Clear the RHS. |
1162 | RHS.clear(); |
1163 | |
1164 | return *this; |
1165 | } |
1166 | |
1167 | // If we have to grow to have enough elements, destroy the current elements. |
1168 | // This allows us to avoid copying them during the grow. |
1169 | // FIXME: this may not actually make any sense if we can efficiently move |
1170 | // elements. |
1171 | if (this->capacity() < RHSSize) { |
1172 | // Destroy current elements. |
1173 | this->clear(); |
1174 | CurSize = 0; |
1175 | this->grow(RHSSize); |
1176 | } else if (CurSize) { |
1177 | // Otherwise, use assignment for the already-constructed elements. |
1178 | std::move(RHS.begin(), RHS.begin() + CurSize, this->begin()); |
1179 | } |
1180 | |
1181 | // Move-construct the new elements in place. |
1182 | this->uninitialized_move( |
1183 | RHS.begin() + CurSize, RHS.end(), this->begin() + CurSize); |
1184 | |
1185 | // Set end. |
1186 | this->set_size(RHSSize); |
1187 | |
1188 | RHS.clear(); |
1189 | return *this; |
1190 | } |
1191 | |
1192 | /// Storage for the SmallVector elements. This is specialized for the N=0 case |
1193 | /// to avoid allocating unnecessary storage. |
1194 | template <typename T, unsigned N> |
1195 | struct SmallVectorStorage { |
1196 | alignas(T) char InlineElts[N * sizeof(T)]; |
1197 | }; |
1198 | |
1199 | /// We need the storage to be properly aligned even for small-size of 0 so that |
1200 | /// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is |
1201 | /// well-defined. |
1202 | template <typename T> |
1203 | struct alignas(T) SmallVectorStorage<T, 0> {}; |
1204 | |
1205 | /// Forward declaration of SmallVector so that |
1206 | /// calculateSmallVectorDefaultInlinedElements can reference |
1207 | /// `sizeof(SmallVector<T, 0>)`. |
1208 | template <typename T, unsigned N> |
1209 | class /* LLVM_GSL_OWNER */ SmallVector; |
1210 | |
1211 | /// Helper class for calculating the default number of inline elements for |
1212 | /// `SmallVector<T>`. |
1213 | /// |
1214 | /// This should be migrated to a constexpr function when our minimum |
1215 | /// compiler support is enough for multi-statement constexpr functions. |
1216 | template <typename T> |
1217 | struct CalculateSmallVectorDefaultInlinedElements { |
1218 | // Parameter controlling the default number of inlined elements |
1219 | // for `SmallVector<T>`. |
1220 | // |
1221 | // The default number of inlined elements ensures that |
1222 | // 1. There is at least one inlined element. |
1223 | // 2. `sizeof(SmallVector<T>) <= kPreferredSmallVectorSizeof` unless |
1224 | // it contradicts 1. |
1225 | static constexpr size_t kPreferredSmallVectorSizeof = 64; |
1226 | |
1227 | // static_assert that sizeof(T) is not "too big". |
1228 | // |
1229 | // Because our policy guarantees at least one inlined element, it is possible |
1230 | // for an arbitrarily large inlined element to allocate an arbitrarily large |
1231 | // amount of inline storage. We generally consider it an antipattern for a |
1232 | // SmallVector to allocate an excessive amount of inline storage, so we want |
1233 | // to call attention to these cases and make sure that users are making an |
1234 | // intentional decision if they request a lot of inline storage. |
1235 | // |
1236 | // We want this assertion to trigger in pathological cases, but otherwise |
1237 | // not be too easy to hit. To accomplish that, the cutoff is actually somewhat |
1238 | // larger than kPreferredSmallVectorSizeof (otherwise, |
1239 | // `SmallVector<SmallVector<T>>` would be one easy way to trip it, and that |
1240 | // pattern seems useful in practice). |
1241 | // |
1242 | // One wrinkle is that this assertion is in theory non-portable, since |
1243 | // sizeof(T) is in general platform-dependent. However, we don't expect this |
1244 | // to be much of an issue, because most LLVM development happens on 64-bit |
1245 | // hosts, and therefore sizeof(T) is expected to *decrease* when compiled for |
1246 | // 32-bit hosts, dodging the issue. The reverse situation, where development |
1247 | // happens on a 32-bit host and then fails due to sizeof(T) *increasing* on a |
1248 | // 64-bit host, is expected to be very rare. |
1249 | static_assert( |
1250 | sizeof(T) <= 256, |
1251 | "You are trying to use a default number of inlined elements for " |
1252 | "`SmallVector<T>` but `sizeof(T)` is really big! Please use an " |
1253 | "explicit number of inlined elements with `SmallVector<T, N>` to make " |
1254 | "sure you really want that much inline storage." ); |
1255 | |
1256 | // Discount the size of the header itself when calculating the maximum inline |
1257 | // bytes. |
1258 | static constexpr size_t PreferredInlineBytes = |
1259 | kPreferredSmallVectorSizeof - sizeof(SmallVector<T, 0>); |
1260 | static constexpr size_t NumElementsThatFit = PreferredInlineBytes / sizeof(T); |
1261 | static constexpr size_t value = |
1262 | NumElementsThatFit == 0 ? 1 : NumElementsThatFit; |
1263 | }; |
1264 | |
1265 | /// This is a 'vector' (really, a variable-sized array), optimized |
1266 | /// for the case when the array is small. It contains some number of elements |
1267 | /// in-place, which allows it to avoid heap allocation when the actual number of |
1268 | /// elements is below that threshold. This allows normal "small" cases to be |
1269 | /// fast without losing generality for large inputs. |
1270 | /// |
1271 | /// \note |
1272 | /// In the absence of a well-motivated choice for the number of inlined |
1273 | /// elements \p N, it is recommended to use \c SmallVector<T> (that is, |
1274 | /// omitting the \p N). This will choose a default number of inlined elements |
1275 | /// reasonable for allocation on the stack (for example, trying to keep \c |
1276 | /// sizeof(SmallVector<T>) around 64 bytes). |
1277 | /// |
1278 | /// \warning This does not attempt to be exception safe. |
1279 | /// |
1280 | /// \see https://llvm.org/docs/ProgrammersManual.html#llvm-adt-smallvector-h |
1281 | template < |
1282 | typename T, |
1283 | unsigned N = CalculateSmallVectorDefaultInlinedElements<T>::value> |
1284 | class /* LLVM_GSL_OWNER */ SmallVector : public SmallVectorImpl<T>, |
1285 | SmallVectorStorage<T, N> { |
1286 | public: |
1287 | SmallVector() : SmallVectorImpl<T>(N) {} |
1288 | |
1289 | ~SmallVector() { |
1290 | // Destroy the constructed elements in the vector. |
1291 | this->destroy_range(this->begin(), this->end()); |
1292 | } |
1293 | |
1294 | explicit SmallVector(size_t Size, const T& Value = T()) |
1295 | : SmallVectorImpl<T>(N) { |
1296 | this->assign(Size, Value); |
1297 | } |
1298 | |
1299 | template < |
1300 | typename ItTy, |
1301 | typename = std::enable_if_t<std::is_convertible< |
1302 | typename std::iterator_traits<ItTy>::iterator_category, |
1303 | std::input_iterator_tag>::value>> |
1304 | SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) { |
1305 | this->append(S, E); |
1306 | } |
1307 | |
1308 | // note: The enable_if restricts Container to types that have a .begin() and |
1309 | // .end() that return valid input iterators. |
1310 | template < |
1311 | typename Container, |
1312 | std::enable_if_t< |
1313 | std::is_convertible< |
1314 | typename std::iterator_traits< |
1315 | decltype(std::declval<Container>() |
1316 | .begin())>::iterator_category, |
1317 | std::input_iterator_tag>::value && |
1318 | std::is_convertible< |
1319 | typename std::iterator_traits< |
1320 | decltype(std::declval<Container>() |
1321 | .end())>::iterator_category, |
1322 | std::input_iterator_tag>::value, |
1323 | int> = 0> |
1324 | explicit SmallVector(Container&& c) : SmallVectorImpl<T>(N) { |
1325 | this->append(c.begin(), c.end()); |
1326 | } |
1327 | |
1328 | SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) { |
1329 | this->assign(IL); |
1330 | } |
1331 | |
1332 | SmallVector(const SmallVector& RHS) : SmallVectorImpl<T>(N) { |
1333 | if (!RHS.empty()) |
1334 | SmallVectorImpl<T>::operator=(RHS); |
1335 | } |
1336 | |
1337 | SmallVector& operator=(const SmallVector& RHS) { |
1338 | SmallVectorImpl<T>::operator=(RHS); |
1339 | return *this; |
1340 | } |
1341 | |
1342 | SmallVector(SmallVector&& RHS) : SmallVectorImpl<T>(N) { |
1343 | if (!RHS.empty()) |
1344 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
1345 | } |
1346 | |
1347 | // note: The enable_if restricts Container to types that have a .begin() and |
1348 | // .end() that return valid input iterators. |
1349 | template < |
1350 | typename Container, |
1351 | std::enable_if_t< |
1352 | std::is_convertible< |
1353 | typename std::iterator_traits< |
1354 | decltype(std::declval<Container>() |
1355 | .begin())>::iterator_category, |
1356 | std::input_iterator_tag>::value && |
1357 | std::is_convertible< |
1358 | typename std::iterator_traits< |
1359 | decltype(std::declval<Container>() |
1360 | .end())>::iterator_category, |
1361 | std::input_iterator_tag>::value, |
1362 | int> = 0> |
1363 | const SmallVector& operator=(const Container& RHS) { |
1364 | this->assign(RHS.begin(), RHS.end()); |
1365 | return *this; |
1366 | } |
1367 | |
1368 | SmallVector(SmallVectorImpl<T>&& RHS) : SmallVectorImpl<T>(N) { |
1369 | if (!RHS.empty()) |
1370 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
1371 | } |
1372 | |
1373 | SmallVector& operator=(SmallVector&& RHS) { |
1374 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
1375 | return *this; |
1376 | } |
1377 | |
1378 | SmallVector& operator=(SmallVectorImpl<T>&& RHS) { |
1379 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
1380 | return *this; |
1381 | } |
1382 | |
1383 | // note: The enable_if restricts Container to types that have a .begin() and |
1384 | // .end() that return valid input iterators. |
1385 | template < |
1386 | typename Container, |
1387 | std::enable_if_t< |
1388 | std::is_convertible< |
1389 | typename std::iterator_traits< |
1390 | decltype(std::declval<Container>() |
1391 | .begin())>::iterator_category, |
1392 | std::input_iterator_tag>::value && |
1393 | std::is_convertible< |
1394 | typename std::iterator_traits< |
1395 | decltype(std::declval<Container>() |
1396 | .end())>::iterator_category, |
1397 | std::input_iterator_tag>::value, |
1398 | int> = 0> |
1399 | const SmallVector& operator=(Container&& C) { |
1400 | this->assign(C.begin(), C.end()); |
1401 | return *this; |
1402 | } |
1403 | |
1404 | SmallVector& operator=(std::initializer_list<T> IL) { |
1405 | this->assign(IL); |
1406 | return *this; |
1407 | } |
1408 | }; |
1409 | |
1410 | template <typename T, unsigned N> |
1411 | inline size_t capacity_in_bytes(const SmallVector<T, N>& X) { |
1412 | return X.capacity_in_bytes(); |
1413 | } |
1414 | |
1415 | template <typename T, unsigned N> |
1416 | std::ostream& operator<<(std::ostream& out, const SmallVector<T, N>& list) { |
1417 | int i = 0; |
1418 | out << "[" ; |
1419 | for (auto e : list) { |
1420 | if (i++ > 0) |
1421 | out << ", " ; |
1422 | out << e; |
1423 | } |
1424 | out << "]" ; |
1425 | return out; |
1426 | } |
1427 | |
1428 | template <typename RangeType> |
1429 | using ValueTypeFromRangeType = |
1430 | typename std::remove_const<typename std::remove_reference< |
1431 | decltype(*std::begin(std::declval<RangeType&>()))>::type>::type; |
1432 | |
1433 | /// Given a range of type R, iterate the entire range and return a |
1434 | /// SmallVector with elements of the vector. This is useful, for example, |
1435 | /// when you want to iterate a range and then sort the results. |
1436 | template <unsigned Size, typename R> |
1437 | SmallVector<ValueTypeFromRangeType<R>, Size> to_vector(R&& Range) { |
1438 | return {std::begin(Range), std::end(Range)}; |
1439 | } |
1440 | template <typename R> |
1441 | SmallVector< |
1442 | ValueTypeFromRangeType<R>, |
1443 | CalculateSmallVectorDefaultInlinedElements< |
1444 | ValueTypeFromRangeType<R>>::value> |
1445 | to_vector(R&& Range) { |
1446 | return {std::begin(Range), std::end(Range)}; |
1447 | } |
1448 | |
1449 | } // end namespace c10 |
1450 | |
1451 | namespace std { |
1452 | |
1453 | /// Implement std::swap in terms of SmallVector swap. |
1454 | template <typename T> |
1455 | inline void swap(c10::SmallVectorImpl<T>& LHS, c10::SmallVectorImpl<T>& RHS) { |
1456 | LHS.swap(RHS); |
1457 | } |
1458 | |
1459 | /// Implement std::swap in terms of SmallVector swap. |
1460 | template <typename T, unsigned N> |
1461 | inline void swap(c10::SmallVector<T, N>& LHS, c10::SmallVector<T, N>& RHS) { |
1462 | LHS.swap(RHS); |
1463 | } |
1464 | |
1465 | } // end namespace std |
1466 | |
1467 | C10_CLANG_DIAGNOSTIC_POP() |
1468 | |