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 | /// \file |
10 | /// This file defines the SmallVector class. |
11 | /// |
12 | //===----------------------------------------------------------------------===// |
13 | |
14 | #ifndef LLVM_ADT_SMALLVECTOR_H |
15 | #define LLVM_ADT_SMALLVECTOR_H |
16 | |
17 | #include "llvm/Support/Compiler.h" |
18 | #include "llvm/Support/type_traits.h" |
19 | #include <algorithm> |
20 | #include <cassert> |
21 | #include <cstddef> |
22 | #include <cstdlib> |
23 | #include <cstring> |
24 | #include <functional> |
25 | #include <initializer_list> |
26 | #include <iterator> |
27 | #include <limits> |
28 | #include <memory> |
29 | #include <new> |
30 | #include <type_traits> |
31 | #include <utility> |
32 | |
33 | namespace llvm { |
34 | |
35 | template <typename T> class ArrayRef; |
36 | |
37 | template <typename IteratorT> class iterator_range; |
38 | |
39 | template <class Iterator> |
40 | using EnableIfConvertibleToInputIterator = std::enable_if_t<std::is_convertible< |
41 | typename std::iterator_traits<Iterator>::iterator_category, |
42 | std::input_iterator_tag>::value>; |
43 | |
44 | /// This is all the stuff common to all SmallVectors. |
45 | /// |
46 | /// The template parameter specifies the type which should be used to hold the |
47 | /// Size and Capacity of the SmallVector, so it can be adjusted. |
48 | /// Using 32 bit size is desirable to shrink the size of the SmallVector. |
49 | /// Using 64 bit size is desirable for cases like SmallVector<char>, where a |
50 | /// 32 bit size would limit the vector to ~4GB. SmallVectors are used for |
51 | /// buffering bitcode output - which can exceed 4GB. |
52 | template <class Size_T> class SmallVectorBase { |
53 | protected: |
54 | void *BeginX; |
55 | Size_T Size = 0, Capacity; |
56 | |
57 | /// The maximum value of the Size_T used. |
58 | static constexpr size_t SizeTypeMax() { |
59 | return std::numeric_limits<Size_T>::max(); |
60 | } |
61 | |
62 | SmallVectorBase() = delete; |
63 | SmallVectorBase(void *FirstEl, size_t TotalCapacity) |
64 | : BeginX(FirstEl), Capacity(TotalCapacity) {} |
65 | |
66 | /// This is a helper for \a grow() that's out of line to reduce code |
67 | /// duplication. This function will report a fatal error if it can't grow at |
68 | /// least to \p MinSize. |
69 | void *mallocForGrow(void *FirstEl, size_t MinSize, size_t TSize, |
70 | size_t &NewCapacity); |
71 | |
72 | /// This is an implementation of the grow() method which only works |
73 | /// on POD-like data types and is out of line to reduce code duplication. |
74 | /// This function will report a fatal error if it cannot increase capacity. |
75 | void grow_pod(void *FirstEl, size_t MinSize, size_t TSize); |
76 | |
77 | /// If vector was first created with capacity 0, getFirstEl() points to the |
78 | /// memory right after, an area unallocated. If a subsequent allocation, |
79 | /// that grows the vector, happens to return the same pointer as getFirstEl(), |
80 | /// get a new allocation, otherwise isSmall() will falsely return that no |
81 | /// allocation was done (true) and the memory will not be freed in the |
82 | /// destructor. If a VSize is given (vector size), also copy that many |
83 | /// elements to the new allocation - used if realloca fails to increase |
84 | /// space, and happens to allocate precisely at BeginX. |
85 | /// This is unlikely to be called often, but resolves a memory leak when the |
86 | /// situation does occur. |
87 | void *replaceAllocation(void *NewElts, size_t TSize, size_t NewCapacity, |
88 | size_t VSize = 0); |
89 | |
90 | public: |
91 | size_t size() const { return Size; } |
92 | size_t capacity() const { return Capacity; } |
93 | |
94 | [[nodiscard]] bool empty() const { return !Size; } |
95 | |
96 | protected: |
97 | /// Set the array size to \p N, which the current array must have enough |
98 | /// capacity for. |
99 | /// |
100 | /// This does not construct or destroy any elements in the vector. |
101 | void set_size(size_t N) { |
102 | assert(N <= capacity()); |
103 | Size = N; |
104 | } |
105 | }; |
106 | |
107 | template <class T> |
108 | using SmallVectorSizeType = |
109 | std::conditional_t<sizeof(T) < 4 && sizeof(void *) >= 8, uint64_t, |
110 | uint32_t>; |
111 | |
112 | /// Figure out the offset of the first element. |
113 | template <class T, typename = void> struct SmallVectorAlignmentAndSize { |
114 | alignas(SmallVectorBase<SmallVectorSizeType<T>>) char Base[sizeof( |
115 | SmallVectorBase<SmallVectorSizeType<T>>)]; |
116 | alignas(T) char FirstEl[sizeof(T)]; |
117 | }; |
118 | |
119 | /// This is the part of SmallVectorTemplateBase which does not depend on whether |
120 | /// the type T is a POD. The extra dummy template argument is used by ArrayRef |
121 | /// to avoid unnecessarily requiring T to be complete. |
122 | template <typename T, typename = void> |
123 | class SmallVectorTemplateCommon |
124 | : public SmallVectorBase<SmallVectorSizeType<T>> { |
125 | using Base = SmallVectorBase<SmallVectorSizeType<T>>; |
126 | |
127 | protected: |
128 | /// Find the address of the first element. For this pointer math to be valid |
129 | /// with small-size of 0 for T with lots of alignment, it's important that |
130 | /// SmallVectorStorage is properly-aligned even for small-size of 0. |
131 | void *getFirstEl() const { |
132 | return const_cast<void *>(reinterpret_cast<const void *>( |
133 | reinterpret_cast<const char *>(this) + |
134 | offsetof(SmallVectorAlignmentAndSize<T>, FirstEl))); |
135 | } |
136 | // Space after 'FirstEl' is clobbered, do not add any instance vars after it. |
137 | |
138 | SmallVectorTemplateCommon(size_t Size) : Base(getFirstEl(), Size) {} |
139 | |
140 | void grow_pod(size_t MinSize, size_t TSize) { |
141 | Base::grow_pod(getFirstEl(), MinSize, TSize); |
142 | } |
143 | |
144 | /// Return true if this is a smallvector which has not had dynamic |
145 | /// memory allocated for it. |
146 | bool isSmall() const { return this->BeginX == getFirstEl(); } |
147 | |
148 | /// Put this vector in a state of being small. |
149 | void resetToSmall() { |
150 | this->BeginX = getFirstEl(); |
151 | this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect. |
152 | } |
153 | |
154 | /// Return true if V is an internal reference to the given range. |
155 | bool isReferenceToRange(const void *V, const void *First, const void *Last) const { |
156 | // Use std::less to avoid UB. |
157 | std::less<> LessThan; |
158 | return !LessThan(V, First) && LessThan(V, Last); |
159 | } |
160 | |
161 | /// Return true if V is an internal reference to this vector. |
162 | bool isReferenceToStorage(const void *V) const { |
163 | return isReferenceToRange(V, First: this->begin(), Last: this->end()); |
164 | } |
165 | |
166 | /// Return true if First and Last form a valid (possibly empty) range in this |
167 | /// vector's storage. |
168 | bool isRangeInStorage(const void *First, const void *Last) const { |
169 | // Use std::less to avoid UB. |
170 | std::less<> LessThan; |
171 | return !LessThan(First, this->begin()) && !LessThan(Last, First) && |
172 | !LessThan(this->end(), Last); |
173 | } |
174 | |
175 | /// Return true unless Elt will be invalidated by resizing the vector to |
176 | /// NewSize. |
177 | bool isSafeToReferenceAfterResize(const void *Elt, size_t NewSize) { |
178 | // Past the end. |
179 | if (LLVM_LIKELY(!isReferenceToStorage(Elt))) |
180 | return true; |
181 | |
182 | // Return false if Elt will be destroyed by shrinking. |
183 | if (NewSize <= this->size()) |
184 | return Elt < this->begin() + NewSize; |
185 | |
186 | // Return false if we need to grow. |
187 | return NewSize <= this->capacity(); |
188 | } |
189 | |
190 | /// Check whether Elt will be invalidated by resizing the vector to NewSize. |
191 | void assertSafeToReferenceAfterResize(const void *Elt, size_t NewSize) { |
192 | assert(isSafeToReferenceAfterResize(Elt, NewSize) && |
193 | "Attempting to reference an element of the vector in an operation " |
194 | "that invalidates it" ); |
195 | } |
196 | |
197 | /// Check whether Elt will be invalidated by increasing the size of the |
198 | /// vector by N. |
199 | void assertSafeToAdd(const void *Elt, size_t N = 1) { |
200 | this->assertSafeToReferenceAfterResize(Elt, this->size() + N); |
201 | } |
202 | |
203 | /// Check whether any part of the range will be invalidated by clearing. |
204 | void assertSafeToReferenceAfterClear(const T *From, const T *To) { |
205 | if (From == To) |
206 | return; |
207 | this->assertSafeToReferenceAfterResize(From, 0); |
208 | this->assertSafeToReferenceAfterResize(To - 1, 0); |
209 | } |
210 | template < |
211 | class ItTy, |
212 | std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value, |
213 | bool> = false> |
214 | void assertSafeToReferenceAfterClear(ItTy, ItTy) {} |
215 | |
216 | /// Check whether any part of the range will be invalidated by growing. |
217 | void assertSafeToAddRange(const T *From, const T *To) { |
218 | if (From == To) |
219 | return; |
220 | this->assertSafeToAdd(From, To - From); |
221 | this->assertSafeToAdd(To - 1, To - From); |
222 | } |
223 | template < |
224 | class ItTy, |
225 | std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value, |
226 | bool> = false> |
227 | void assertSafeToAddRange(ItTy, ItTy) {} |
228 | |
229 | /// Reserve enough space to add one element, and return the updated element |
230 | /// pointer in case it was a reference to the storage. |
231 | template <class U> |
232 | static const T *reserveForParamAndGetAddressImpl(U *This, const T &Elt, |
233 | size_t N) { |
234 | size_t NewSize = This->size() + N; |
235 | if (LLVM_LIKELY(NewSize <= This->capacity())) |
236 | return &Elt; |
237 | |
238 | bool ReferencesStorage = false; |
239 | int64_t Index = -1; |
240 | if (!U::TakesParamByValue) { |
241 | if (LLVM_UNLIKELY(This->isReferenceToStorage(&Elt))) { |
242 | ReferencesStorage = true; |
243 | Index = &Elt - This->begin(); |
244 | } |
245 | } |
246 | This->grow(NewSize); |
247 | return ReferencesStorage ? This->begin() + Index : &Elt; |
248 | } |
249 | |
250 | public: |
251 | using size_type = size_t; |
252 | using difference_type = ptrdiff_t; |
253 | using value_type = T; |
254 | using iterator = T *; |
255 | using const_iterator = const T *; |
256 | |
257 | using const_reverse_iterator = std::reverse_iterator<const_iterator>; |
258 | using reverse_iterator = std::reverse_iterator<iterator>; |
259 | |
260 | using reference = T &; |
261 | using const_reference = const T &; |
262 | using pointer = T *; |
263 | using const_pointer = const T *; |
264 | |
265 | using Base::capacity; |
266 | using Base::empty; |
267 | using Base::size; |
268 | |
269 | // forward iterator creation methods. |
270 | iterator begin() { return (iterator)this->BeginX; } |
271 | const_iterator begin() const { return (const_iterator)this->BeginX; } |
272 | iterator end() { return begin() + size(); } |
273 | const_iterator end() const { return begin() + size(); } |
274 | |
275 | // reverse iterator creation methods. |
276 | reverse_iterator rbegin() { return reverse_iterator(end()); } |
277 | const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); } |
278 | reverse_iterator rend() { return reverse_iterator(begin()); } |
279 | const_reverse_iterator rend() const { return const_reverse_iterator(begin());} |
280 | |
281 | size_type size_in_bytes() const { return size() * sizeof(T); } |
282 | size_type max_size() const { |
283 | return std::min(this->SizeTypeMax(), size_type(-1) / sizeof(T)); |
284 | } |
285 | |
286 | size_t capacity_in_bytes() const { return capacity() * sizeof(T); } |
287 | |
288 | /// Return a pointer to the vector's buffer, even if empty(). |
289 | pointer data() { return pointer(begin()); } |
290 | /// Return a pointer to the vector's buffer, even if empty(). |
291 | const_pointer data() const { return const_pointer(begin()); } |
292 | |
293 | reference operator[](size_type idx) { |
294 | assert(idx < size()); |
295 | return begin()[idx]; |
296 | } |
297 | const_reference operator[](size_type idx) const { |
298 | assert(idx < size()); |
299 | return begin()[idx]; |
300 | } |
301 | |
302 | reference front() { |
303 | assert(!empty()); |
304 | return begin()[0]; |
305 | } |
306 | const_reference front() const { |
307 | assert(!empty()); |
308 | return begin()[0]; |
309 | } |
310 | |
311 | reference back() { |
312 | assert(!empty()); |
313 | return end()[-1]; |
314 | } |
315 | const_reference back() const { |
316 | assert(!empty()); |
317 | return end()[-1]; |
318 | } |
319 | }; |
320 | |
321 | /// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put |
322 | /// method implementations that are designed to work with non-trivial T's. |
323 | /// |
324 | /// We approximate is_trivially_copyable with trivial move/copy construction and |
325 | /// trivial destruction. While the standard doesn't specify that you're allowed |
326 | /// copy these types with memcpy, there is no way for the type to observe this. |
327 | /// This catches the important case of std::pair<POD, POD>, which is not |
328 | /// trivially assignable. |
329 | template <typename T, bool = (std::is_trivially_copy_constructible<T>::value) && |
330 | (std::is_trivially_move_constructible<T>::value) && |
331 | std::is_trivially_destructible<T>::value> |
332 | class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> { |
333 | friend class SmallVectorTemplateCommon<T>; |
334 | |
335 | protected: |
336 | static constexpr bool TakesParamByValue = false; |
337 | using ValueParamT = const T &; |
338 | |
339 | SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} |
340 | |
341 | static void destroy_range(T *S, T *E) { |
342 | while (S != E) { |
343 | --E; |
344 | E->~T(); |
345 | } |
346 | } |
347 | |
348 | /// Move the range [I, E) into the uninitialized memory starting with "Dest", |
349 | /// constructing elements as needed. |
350 | template<typename It1, typename It2> |
351 | static void uninitialized_move(It1 I, It1 E, It2 Dest) { |
352 | std::uninitialized_move(I, E, Dest); |
353 | } |
354 | |
355 | /// Copy the range [I, E) onto the uninitialized memory starting with "Dest", |
356 | /// constructing elements as needed. |
357 | template<typename It1, typename It2> |
358 | static void uninitialized_copy(It1 I, It1 E, It2 Dest) { |
359 | std::uninitialized_copy(I, E, Dest); |
360 | } |
361 | |
362 | /// Grow the allocated memory (without initializing new elements), doubling |
363 | /// the size of the allocated memory. Guarantees space for at least one more |
364 | /// element, or MinSize more elements if specified. |
365 | void grow(size_t MinSize = 0); |
366 | |
367 | /// Create a new allocation big enough for \p MinSize and pass back its size |
368 | /// in \p NewCapacity. This is the first section of \a grow(). |
369 | T *mallocForGrow(size_t MinSize, size_t &NewCapacity); |
370 | |
371 | /// Move existing elements over to the new allocation \p NewElts, the middle |
372 | /// section of \a grow(). |
373 | void moveElementsForGrow(T *NewElts); |
374 | |
375 | /// Transfer ownership of the allocation, finishing up \a grow(). |
376 | void takeAllocationForGrow(T *NewElts, size_t NewCapacity); |
377 | |
378 | /// Reserve enough space to add one element, and return the updated element |
379 | /// pointer in case it was a reference to the storage. |
380 | const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) { |
381 | return this->reserveForParamAndGetAddressImpl(this, Elt, N); |
382 | } |
383 | |
384 | /// Reserve enough space to add one element, and return the updated element |
385 | /// pointer in case it was a reference to the storage. |
386 | T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) { |
387 | return const_cast<T *>( |
388 | this->reserveForParamAndGetAddressImpl(this, Elt, N)); |
389 | } |
390 | |
391 | static T &&forward_value_param(T &&V) { return std::move(V); } |
392 | static const T &forward_value_param(const T &V) { return V; } |
393 | |
394 | void growAndAssign(size_t NumElts, const T &Elt) { |
395 | // Grow manually in case Elt is an internal reference. |
396 | size_t NewCapacity; |
397 | T *NewElts = mallocForGrow(MinSize: NumElts, NewCapacity); |
398 | std::uninitialized_fill_n(NewElts, NumElts, Elt); |
399 | this->destroy_range(this->begin(), this->end()); |
400 | takeAllocationForGrow(NewElts, NewCapacity); |
401 | this->set_size(NumElts); |
402 | } |
403 | |
404 | template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) { |
405 | // Grow manually in case one of Args is an internal reference. |
406 | size_t NewCapacity; |
407 | T *NewElts = mallocForGrow(MinSize: 0, NewCapacity); |
408 | ::new ((void *)(NewElts + this->size())) T(std::forward<ArgTypes>(Args)...); |
409 | moveElementsForGrow(NewElts); |
410 | takeAllocationForGrow(NewElts, NewCapacity); |
411 | this->set_size(this->size() + 1); |
412 | return this->back(); |
413 | } |
414 | |
415 | public: |
416 | void push_back(const T &Elt) { |
417 | const T *EltPtr = reserveForParamAndGetAddress(Elt); |
418 | ::new ((void *)this->end()) T(*EltPtr); |
419 | this->set_size(this->size() + 1); |
420 | } |
421 | |
422 | void push_back(T &&Elt) { |
423 | T *EltPtr = reserveForParamAndGetAddress(Elt); |
424 | ::new ((void *)this->end()) T(::std::move(*EltPtr)); |
425 | this->set_size(this->size() + 1); |
426 | } |
427 | |
428 | void pop_back() { |
429 | this->set_size(this->size() - 1); |
430 | this->end()->~T(); |
431 | } |
432 | }; |
433 | |
434 | // Define this out-of-line to dissuade the C++ compiler from inlining it. |
435 | template <typename T, bool TriviallyCopyable> |
436 | void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) { |
437 | size_t NewCapacity; |
438 | T *NewElts = mallocForGrow(MinSize, NewCapacity); |
439 | moveElementsForGrow(NewElts); |
440 | takeAllocationForGrow(NewElts, NewCapacity); |
441 | } |
442 | |
443 | template <typename T, bool TriviallyCopyable> |
444 | T *SmallVectorTemplateBase<T, TriviallyCopyable>::mallocForGrow( |
445 | size_t MinSize, size_t &NewCapacity) { |
446 | return static_cast<T *>( |
447 | SmallVectorBase<SmallVectorSizeType<T>>::mallocForGrow( |
448 | this->getFirstEl(), MinSize, sizeof(T), NewCapacity)); |
449 | } |
450 | |
451 | // Define this out-of-line to dissuade the C++ compiler from inlining it. |
452 | template <typename T, bool TriviallyCopyable> |
453 | void SmallVectorTemplateBase<T, TriviallyCopyable>::moveElementsForGrow( |
454 | T *NewElts) { |
455 | // Move the elements over. |
456 | this->uninitialized_move(this->begin(), this->end(), NewElts); |
457 | |
458 | // Destroy the original elements. |
459 | destroy_range(S: this->begin(), E: this->end()); |
460 | } |
461 | |
462 | // Define this out-of-line to dissuade the C++ compiler from inlining it. |
463 | template <typename T, bool TriviallyCopyable> |
464 | void SmallVectorTemplateBase<T, TriviallyCopyable>::takeAllocationForGrow( |
465 | T *NewElts, size_t NewCapacity) { |
466 | // If this wasn't grown from the inline copy, deallocate the old space. |
467 | if (!this->isSmall()) |
468 | free(this->begin()); |
469 | |
470 | this->BeginX = NewElts; |
471 | this->Capacity = NewCapacity; |
472 | } |
473 | |
474 | /// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put |
475 | /// method implementations that are designed to work with trivially copyable |
476 | /// T's. This allows using memcpy in place of copy/move construction and |
477 | /// skipping destruction. |
478 | template <typename T> |
479 | class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> { |
480 | friend class SmallVectorTemplateCommon<T>; |
481 | |
482 | protected: |
483 | /// True if it's cheap enough to take parameters by value. Doing so avoids |
484 | /// overhead related to mitigations for reference invalidation. |
485 | static constexpr bool TakesParamByValue = sizeof(T) <= 2 * sizeof(void *); |
486 | |
487 | /// Either const T& or T, depending on whether it's cheap enough to take |
488 | /// parameters by value. |
489 | using ValueParamT = std::conditional_t<TakesParamByValue, T, const T &>; |
490 | |
491 | SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} |
492 | |
493 | // No need to do a destroy loop for POD's. |
494 | static void destroy_range(T *, T *) {} |
495 | |
496 | /// Move the range [I, E) onto the uninitialized memory |
497 | /// starting with "Dest", constructing elements into it as needed. |
498 | template<typename It1, typename It2> |
499 | static void uninitialized_move(It1 I, It1 E, It2 Dest) { |
500 | // Just do a copy. |
501 | uninitialized_copy(I, E, Dest); |
502 | } |
503 | |
504 | /// Copy the range [I, E) onto the uninitialized memory |
505 | /// starting with "Dest", constructing elements into it as needed. |
506 | template<typename It1, typename It2> |
507 | static void uninitialized_copy(It1 I, It1 E, It2 Dest) { |
508 | // Arbitrary iterator types; just use the basic implementation. |
509 | std::uninitialized_copy(I, E, Dest); |
510 | } |
511 | |
512 | /// Copy the range [I, E) onto the uninitialized memory |
513 | /// starting with "Dest", constructing elements into it as needed. |
514 | template <typename T1, typename T2> |
515 | static void uninitialized_copy( |
516 | T1 *I, T1 *E, T2 *Dest, |
517 | std::enable_if_t<std::is_same<std::remove_const_t<T1>, T2>::value> * = |
518 | nullptr) { |
519 | // Use memcpy for PODs iterated by pointers (which includes SmallVector |
520 | // iterators): std::uninitialized_copy optimizes to memmove, but we can |
521 | // use memcpy here. Note that I and E are iterators and thus might be |
522 | // invalid for memcpy if they are equal. |
523 | if (I != E) |
524 | memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T)); |
525 | } |
526 | |
527 | /// Double the size of the allocated memory, guaranteeing space for at |
528 | /// least one more element or MinSize if specified. |
529 | void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); } |
530 | |
531 | /// Reserve enough space to add one element, and return the updated element |
532 | /// pointer in case it was a reference to the storage. |
533 | const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) { |
534 | return this->reserveForParamAndGetAddressImpl(this, Elt, N); |
535 | } |
536 | |
537 | /// Reserve enough space to add one element, and return the updated element |
538 | /// pointer in case it was a reference to the storage. |
539 | T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) { |
540 | return const_cast<T *>( |
541 | this->reserveForParamAndGetAddressImpl(this, Elt, N)); |
542 | } |
543 | |
544 | /// Copy \p V or return a reference, depending on \a ValueParamT. |
545 | static ValueParamT forward_value_param(ValueParamT V) { return V; } |
546 | |
547 | void growAndAssign(size_t NumElts, T Elt) { |
548 | // Elt has been copied in case it's an internal reference, side-stepping |
549 | // reference invalidation problems without losing the realloc optimization. |
550 | this->set_size(0); |
551 | this->grow(NumElts); |
552 | std::uninitialized_fill_n(this->begin(), NumElts, Elt); |
553 | this->set_size(NumElts); |
554 | } |
555 | |
556 | template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) { |
557 | // Use push_back with a copy in case Args has an internal reference, |
558 | // side-stepping reference invalidation problems without losing the realloc |
559 | // optimization. |
560 | push_back(Elt: T(std::forward<ArgTypes>(Args)...)); |
561 | return this->back(); |
562 | } |
563 | |
564 | public: |
565 | void push_back(ValueParamT Elt) { |
566 | const T *EltPtr = reserveForParamAndGetAddress(Elt); |
567 | memcpy(reinterpret_cast<void *>(this->end()), EltPtr, sizeof(T)); |
568 | this->set_size(this->size() + 1); |
569 | } |
570 | |
571 | void pop_back() { this->set_size(this->size() - 1); } |
572 | }; |
573 | |
574 | /// This class consists of common code factored out of the SmallVector class to |
575 | /// reduce code duplication based on the SmallVector 'N' template parameter. |
576 | template <typename T> |
577 | class SmallVectorImpl : public SmallVectorTemplateBase<T> { |
578 | using SuperClass = SmallVectorTemplateBase<T>; |
579 | |
580 | public: |
581 | using iterator = typename SuperClass::iterator; |
582 | using const_iterator = typename SuperClass::const_iterator; |
583 | using reference = typename SuperClass::reference; |
584 | using size_type = typename SuperClass::size_type; |
585 | |
586 | protected: |
587 | using SmallVectorTemplateBase<T>::TakesParamByValue; |
588 | using ValueParamT = typename SuperClass::ValueParamT; |
589 | |
590 | // Default ctor - Initialize to empty. |
591 | explicit SmallVectorImpl(unsigned N) |
592 | : SmallVectorTemplateBase<T>(N) {} |
593 | |
594 | void assignRemote(SmallVectorImpl &&RHS) { |
595 | this->destroy_range(this->begin(), this->end()); |
596 | if (!this->isSmall()) |
597 | free(this->begin()); |
598 | this->BeginX = RHS.BeginX; |
599 | this->Size = RHS.Size; |
600 | this->Capacity = RHS.Capacity; |
601 | RHS.resetToSmall(); |
602 | } |
603 | |
604 | public: |
605 | SmallVectorImpl(const SmallVectorImpl &) = delete; |
606 | |
607 | ~SmallVectorImpl() { |
608 | // Subclass has already destructed this vector's elements. |
609 | // If this wasn't grown from the inline copy, deallocate the old space. |
610 | if (!this->isSmall()) |
611 | free(this->begin()); |
612 | } |
613 | |
614 | void clear() { |
615 | this->destroy_range(this->begin(), this->end()); |
616 | this->Size = 0; |
617 | } |
618 | |
619 | private: |
620 | // Make set_size() private to avoid misuse in subclasses. |
621 | using SuperClass::set_size; |
622 | |
623 | template <bool ForOverwrite> void resizeImpl(size_type N) { |
624 | if (N == this->size()) |
625 | return; |
626 | |
627 | if (N < this->size()) { |
628 | this->truncate(N); |
629 | return; |
630 | } |
631 | |
632 | this->reserve(N); |
633 | for (auto I = this->end(), E = this->begin() + N; I != E; ++I) |
634 | if (ForOverwrite) |
635 | new (&*I) T; |
636 | else |
637 | new (&*I) T(); |
638 | this->set_size(N); |
639 | } |
640 | |
641 | public: |
642 | void resize(size_type N) { resizeImpl<false>(N); } |
643 | |
644 | /// Like resize, but \ref T is POD, the new values won't be initialized. |
645 | void resize_for_overwrite(size_type N) { resizeImpl<true>(N); } |
646 | |
647 | /// Like resize, but requires that \p N is less than \a size(). |
648 | void truncate(size_type N) { |
649 | assert(this->size() >= N && "Cannot increase size with truncate" ); |
650 | this->destroy_range(this->begin() + N, this->end()); |
651 | this->set_size(N); |
652 | } |
653 | |
654 | void resize(size_type N, ValueParamT NV) { |
655 | if (N == this->size()) |
656 | return; |
657 | |
658 | if (N < this->size()) { |
659 | this->truncate(N); |
660 | return; |
661 | } |
662 | |
663 | // N > this->size(). Defer to append. |
664 | this->append(N - this->size(), NV); |
665 | } |
666 | |
667 | void reserve(size_type N) { |
668 | if (this->capacity() < N) |
669 | this->grow(N); |
670 | } |
671 | |
672 | void pop_back_n(size_type NumItems) { |
673 | assert(this->size() >= NumItems); |
674 | truncate(N: this->size() - NumItems); |
675 | } |
676 | |
677 | [[nodiscard]] T pop_back_val() { |
678 | T Result = ::std::move(this->back()); |
679 | this->pop_back(); |
680 | return Result; |
681 | } |
682 | |
683 | void swap(SmallVectorImpl &RHS); |
684 | |
685 | /// Add the specified range to the end of the SmallVector. |
686 | template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>> |
687 | void append(ItTy in_start, ItTy in_end) { |
688 | this->assertSafeToAddRange(in_start, in_end); |
689 | size_type NumInputs = std::distance(in_start, in_end); |
690 | this->reserve(this->size() + NumInputs); |
691 | this->uninitialized_copy(in_start, in_end, this->end()); |
692 | this->set_size(this->size() + NumInputs); |
693 | } |
694 | |
695 | /// Append \p NumInputs copies of \p Elt to the end. |
696 | void append(size_type NumInputs, ValueParamT Elt) { |
697 | const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumInputs); |
698 | std::uninitialized_fill_n(this->end(), NumInputs, *EltPtr); |
699 | this->set_size(this->size() + NumInputs); |
700 | } |
701 | |
702 | void append(std::initializer_list<T> IL) { |
703 | append(IL.begin(), IL.end()); |
704 | } |
705 | |
706 | void append(const SmallVectorImpl &RHS) { append(RHS.begin(), RHS.end()); } |
707 | |
708 | void assign(size_type NumElts, ValueParamT Elt) { |
709 | // Note that Elt could be an internal reference. |
710 | if (NumElts > this->capacity()) { |
711 | this->growAndAssign(NumElts, Elt); |
712 | return; |
713 | } |
714 | |
715 | // Assign over existing elements. |
716 | std::fill_n(this->begin(), std::min(NumElts, this->size()), Elt); |
717 | if (NumElts > this->size()) |
718 | std::uninitialized_fill_n(this->end(), NumElts - this->size(), Elt); |
719 | else if (NumElts < this->size()) |
720 | this->destroy_range(this->begin() + NumElts, this->end()); |
721 | this->set_size(NumElts); |
722 | } |
723 | |
724 | // FIXME: Consider assigning over existing elements, rather than clearing & |
725 | // re-initializing them - for all assign(...) variants. |
726 | |
727 | template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>> |
728 | void assign(ItTy in_start, ItTy in_end) { |
729 | this->assertSafeToReferenceAfterClear(in_start, in_end); |
730 | clear(); |
731 | append(in_start, in_end); |
732 | } |
733 | |
734 | void assign(std::initializer_list<T> IL) { |
735 | clear(); |
736 | append(IL); |
737 | } |
738 | |
739 | void assign(const SmallVectorImpl &RHS) { assign(RHS.begin(), RHS.end()); } |
740 | |
741 | iterator erase(const_iterator CI) { |
742 | // Just cast away constness because this is a non-const member function. |
743 | iterator I = const_cast<iterator>(CI); |
744 | |
745 | assert(this->isReferenceToStorage(CI) && "Iterator to erase is out of bounds." ); |
746 | |
747 | iterator N = I; |
748 | // Shift all elts down one. |
749 | std::move(I+1, this->end(), I); |
750 | // Drop the last elt. |
751 | this->pop_back(); |
752 | return(N); |
753 | } |
754 | |
755 | iterator erase(const_iterator CS, const_iterator CE) { |
756 | // Just cast away constness because this is a non-const member function. |
757 | iterator S = const_cast<iterator>(CS); |
758 | iterator E = const_cast<iterator>(CE); |
759 | |
760 | assert(this->isRangeInStorage(S, E) && "Range to erase is out of bounds." ); |
761 | |
762 | iterator N = S; |
763 | // Shift all elts down. |
764 | iterator I = std::move(E, this->end(), S); |
765 | // Drop the last elts. |
766 | this->destroy_range(I, this->end()); |
767 | this->set_size(I - this->begin()); |
768 | return(N); |
769 | } |
770 | |
771 | private: |
772 | template <class ArgType> iterator insert_one_impl(iterator I, ArgType &&Elt) { |
773 | // Callers ensure that ArgType is derived from T. |
774 | static_assert( |
775 | std::is_same<std::remove_const_t<std::remove_reference_t<ArgType>>, |
776 | T>::value, |
777 | "ArgType must be derived from T!" ); |
778 | |
779 | if (I == this->end()) { // Important special case for empty vector. |
780 | this->push_back(::std::forward<ArgType>(Elt)); |
781 | return this->end()-1; |
782 | } |
783 | |
784 | assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds." ); |
785 | |
786 | // Grow if necessary. |
787 | size_t Index = I - this->begin(); |
788 | std::remove_reference_t<ArgType> *EltPtr = |
789 | this->reserveForParamAndGetAddress(Elt); |
790 | I = this->begin() + Index; |
791 | |
792 | ::new ((void*) this->end()) T(::std::move(this->back())); |
793 | // Push everything else over. |
794 | std::move_backward(I, this->end()-1, this->end()); |
795 | this->set_size(this->size() + 1); |
796 | |
797 | // If we just moved the element we're inserting, be sure to update |
798 | // the reference (never happens if TakesParamByValue). |
799 | static_assert(!TakesParamByValue || std::is_same<ArgType, T>::value, |
800 | "ArgType must be 'T' when taking by value!" ); |
801 | if (!TakesParamByValue && this->isReferenceToRange(EltPtr, I, this->end())) |
802 | ++EltPtr; |
803 | |
804 | *I = ::std::forward<ArgType>(*EltPtr); |
805 | return I; |
806 | } |
807 | |
808 | public: |
809 | iterator insert(iterator I, T &&Elt) { |
810 | return insert_one_impl(I, this->forward_value_param(std::move(Elt))); |
811 | } |
812 | |
813 | iterator insert(iterator I, const T &Elt) { |
814 | return insert_one_impl(I, this->forward_value_param(Elt)); |
815 | } |
816 | |
817 | iterator insert(iterator I, size_type NumToInsert, ValueParamT Elt) { |
818 | // Convert iterator to elt# to avoid invalidating iterator when we reserve() |
819 | size_t InsertElt = I - this->begin(); |
820 | |
821 | if (I == this->end()) { // Important special case for empty vector. |
822 | append(NumToInsert, Elt); |
823 | return this->begin()+InsertElt; |
824 | } |
825 | |
826 | assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds." ); |
827 | |
828 | // Ensure there is enough space, and get the (maybe updated) address of |
829 | // Elt. |
830 | const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumToInsert); |
831 | |
832 | // Uninvalidate the iterator. |
833 | I = this->begin()+InsertElt; |
834 | |
835 | // If there are more elements between the insertion point and the end of the |
836 | // range than there are being inserted, we can use a simple approach to |
837 | // insertion. Since we already reserved space, we know that this won't |
838 | // reallocate the vector. |
839 | if (size_t(this->end()-I) >= NumToInsert) { |
840 | T *OldEnd = this->end(); |
841 | append(std::move_iterator<iterator>(this->end() - NumToInsert), |
842 | std::move_iterator<iterator>(this->end())); |
843 | |
844 | // Copy the existing elements that get replaced. |
845 | std::move_backward(I, OldEnd-NumToInsert, OldEnd); |
846 | |
847 | // If we just moved the element we're inserting, be sure to update |
848 | // the reference (never happens if TakesParamByValue). |
849 | if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end()) |
850 | EltPtr += NumToInsert; |
851 | |
852 | std::fill_n(I, NumToInsert, *EltPtr); |
853 | return I; |
854 | } |
855 | |
856 | // Otherwise, we're inserting more elements than exist already, and we're |
857 | // not inserting at the end. |
858 | |
859 | // Move over the elements that we're about to overwrite. |
860 | T *OldEnd = this->end(); |
861 | this->set_size(this->size() + NumToInsert); |
862 | size_t NumOverwritten = OldEnd-I; |
863 | this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten); |
864 | |
865 | // If we just moved the element we're inserting, be sure to update |
866 | // the reference (never happens if TakesParamByValue). |
867 | if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end()) |
868 | EltPtr += NumToInsert; |
869 | |
870 | // Replace the overwritten part. |
871 | std::fill_n(I, NumOverwritten, *EltPtr); |
872 | |
873 | // Insert the non-overwritten middle part. |
874 | std::uninitialized_fill_n(OldEnd, NumToInsert - NumOverwritten, *EltPtr); |
875 | return I; |
876 | } |
877 | |
878 | template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>> |
879 | iterator insert(iterator I, ItTy From, ItTy To) { |
880 | // Convert iterator to elt# to avoid invalidating iterator when we reserve() |
881 | size_t InsertElt = I - this->begin(); |
882 | |
883 | if (I == this->end()) { // Important special case for empty vector. |
884 | append(From, To); |
885 | return this->begin()+InsertElt; |
886 | } |
887 | |
888 | assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds." ); |
889 | |
890 | // Check that the reserve that follows doesn't invalidate the iterators. |
891 | this->assertSafeToAddRange(From, To); |
892 | |
893 | size_t NumToInsert = std::distance(From, To); |
894 | |
895 | // Ensure there is enough space. |
896 | reserve(N: this->size() + NumToInsert); |
897 | |
898 | // Uninvalidate the iterator. |
899 | I = this->begin()+InsertElt; |
900 | |
901 | // If there are more elements between the insertion point and the end of the |
902 | // range than there are being inserted, we can use a simple approach to |
903 | // insertion. Since we already reserved space, we know that this won't |
904 | // reallocate the vector. |
905 | if (size_t(this->end()-I) >= NumToInsert) { |
906 | T *OldEnd = this->end(); |
907 | append(std::move_iterator<iterator>(this->end() - NumToInsert), |
908 | std::move_iterator<iterator>(this->end())); |
909 | |
910 | // Copy the existing elements that get replaced. |
911 | std::move_backward(I, OldEnd-NumToInsert, OldEnd); |
912 | |
913 | std::copy(From, To, I); |
914 | return I; |
915 | } |
916 | |
917 | // Otherwise, we're inserting more elements than exist already, and we're |
918 | // not inserting at the end. |
919 | |
920 | // Move over the elements that we're about to overwrite. |
921 | T *OldEnd = this->end(); |
922 | this->set_size(this->size() + NumToInsert); |
923 | size_t NumOverwritten = OldEnd-I; |
924 | this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten); |
925 | |
926 | // Replace the overwritten part. |
927 | for (T *J = I; NumOverwritten > 0; --NumOverwritten) { |
928 | *J = *From; |
929 | ++J; ++From; |
930 | } |
931 | |
932 | // Insert the non-overwritten middle part. |
933 | this->uninitialized_copy(From, To, OldEnd); |
934 | return I; |
935 | } |
936 | |
937 | void insert(iterator I, std::initializer_list<T> IL) { |
938 | insert(I, IL.begin(), IL.end()); |
939 | } |
940 | |
941 | template <typename... ArgTypes> reference emplace_back(ArgTypes &&... Args) { |
942 | if (LLVM_UNLIKELY(this->size() >= this->capacity())) |
943 | return this->growAndEmplaceBack(std::forward<ArgTypes>(Args)...); |
944 | |
945 | ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...); |
946 | this->set_size(this->size() + 1); |
947 | return this->back(); |
948 | } |
949 | |
950 | SmallVectorImpl &operator=(const SmallVectorImpl &RHS); |
951 | |
952 | SmallVectorImpl &operator=(SmallVectorImpl &&RHS); |
953 | |
954 | bool operator==(const SmallVectorImpl &RHS) const { |
955 | if (this->size() != RHS.size()) return false; |
956 | return std::equal(this->begin(), this->end(), RHS.begin()); |
957 | } |
958 | bool operator!=(const SmallVectorImpl &RHS) const { |
959 | return !(*this == RHS); |
960 | } |
961 | |
962 | bool operator<(const SmallVectorImpl &RHS) const { |
963 | return std::lexicographical_compare(this->begin(), this->end(), |
964 | RHS.begin(), RHS.end()); |
965 | } |
966 | bool operator>(const SmallVectorImpl &RHS) const { return RHS < *this; } |
967 | bool operator<=(const SmallVectorImpl &RHS) const { return !(*this > RHS); } |
968 | bool operator>=(const SmallVectorImpl &RHS) const { return !(*this < RHS); } |
969 | }; |
970 | |
971 | template <typename T> |
972 | void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) { |
973 | if (this == &RHS) return; |
974 | |
975 | // We can only avoid copying elements if neither vector is small. |
976 | if (!this->isSmall() && !RHS.isSmall()) { |
977 | std::swap(this->BeginX, RHS.BeginX); |
978 | std::swap(this->Size, RHS.Size); |
979 | std::swap(this->Capacity, RHS.Capacity); |
980 | return; |
981 | } |
982 | this->reserve(RHS.size()); |
983 | RHS.reserve(this->size()); |
984 | |
985 | // Swap the shared elements. |
986 | size_t NumShared = this->size(); |
987 | if (NumShared > RHS.size()) NumShared = RHS.size(); |
988 | for (size_type i = 0; i != NumShared; ++i) |
989 | std::swap((*this)[i], RHS[i]); |
990 | |
991 | // Copy over the extra elts. |
992 | if (this->size() > RHS.size()) { |
993 | size_t EltDiff = this->size() - RHS.size(); |
994 | this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end()); |
995 | RHS.set_size(RHS.size() + EltDiff); |
996 | this->destroy_range(this->begin()+NumShared, this->end()); |
997 | this->set_size(NumShared); |
998 | } else if (RHS.size() > this->size()) { |
999 | size_t EltDiff = RHS.size() - this->size(); |
1000 | this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end()); |
1001 | this->set_size(this->size() + EltDiff); |
1002 | this->destroy_range(RHS.begin()+NumShared, RHS.end()); |
1003 | RHS.set_size(NumShared); |
1004 | } |
1005 | } |
1006 | |
1007 | template <typename T> |
1008 | SmallVectorImpl<T> &SmallVectorImpl<T>:: |
1009 | operator=(const SmallVectorImpl<T> &RHS) { |
1010 | // Avoid self-assignment. |
1011 | if (this == &RHS) return *this; |
1012 | |
1013 | // If we already have sufficient space, assign the common elements, then |
1014 | // destroy any excess. |
1015 | size_t RHSSize = RHS.size(); |
1016 | size_t CurSize = this->size(); |
1017 | if (CurSize >= RHSSize) { |
1018 | // Assign common elements. |
1019 | iterator NewEnd; |
1020 | if (RHSSize) |
1021 | NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin()); |
1022 | else |
1023 | NewEnd = this->begin(); |
1024 | |
1025 | // Destroy excess elements. |
1026 | this->destroy_range(NewEnd, this->end()); |
1027 | |
1028 | // Trim. |
1029 | this->set_size(RHSSize); |
1030 | return *this; |
1031 | } |
1032 | |
1033 | // If we have to grow to have enough elements, destroy the current elements. |
1034 | // This allows us to avoid copying them during the grow. |
1035 | // FIXME: don't do this if they're efficiently moveable. |
1036 | if (this->capacity() < RHSSize) { |
1037 | // Destroy current elements. |
1038 | this->clear(); |
1039 | CurSize = 0; |
1040 | this->grow(RHSSize); |
1041 | } else if (CurSize) { |
1042 | // Otherwise, use assignment for the already-constructed elements. |
1043 | std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin()); |
1044 | } |
1045 | |
1046 | // Copy construct the new elements in place. |
1047 | this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(), |
1048 | this->begin()+CurSize); |
1049 | |
1050 | // Set end. |
1051 | this->set_size(RHSSize); |
1052 | return *this; |
1053 | } |
1054 | |
1055 | template <typename T> |
1056 | SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) { |
1057 | // Avoid self-assignment. |
1058 | if (this == &RHS) return *this; |
1059 | |
1060 | // If the RHS isn't small, clear this vector and then steal its buffer. |
1061 | if (!RHS.isSmall()) { |
1062 | this->assignRemote(std::move(RHS)); |
1063 | return *this; |
1064 | } |
1065 | |
1066 | // If we already have sufficient space, assign the common elements, then |
1067 | // destroy any excess. |
1068 | size_t RHSSize = RHS.size(); |
1069 | size_t CurSize = this->size(); |
1070 | if (CurSize >= RHSSize) { |
1071 | // Assign common elements. |
1072 | iterator NewEnd = this->begin(); |
1073 | if (RHSSize) |
1074 | NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd); |
1075 | |
1076 | // Destroy excess elements and trim the bounds. |
1077 | this->destroy_range(NewEnd, this->end()); |
1078 | this->set_size(RHSSize); |
1079 | |
1080 | // Clear the RHS. |
1081 | RHS.clear(); |
1082 | |
1083 | return *this; |
1084 | } |
1085 | |
1086 | // If we have to grow to have enough elements, destroy the current elements. |
1087 | // This allows us to avoid copying them during the grow. |
1088 | // FIXME: this may not actually make any sense if we can efficiently move |
1089 | // elements. |
1090 | if (this->capacity() < RHSSize) { |
1091 | // Destroy current elements. |
1092 | this->clear(); |
1093 | CurSize = 0; |
1094 | this->grow(RHSSize); |
1095 | } else if (CurSize) { |
1096 | // Otherwise, use assignment for the already-constructed elements. |
1097 | std::move(RHS.begin(), RHS.begin()+CurSize, this->begin()); |
1098 | } |
1099 | |
1100 | // Move-construct the new elements in place. |
1101 | this->uninitialized_move(RHS.begin()+CurSize, RHS.end(), |
1102 | this->begin()+CurSize); |
1103 | |
1104 | // Set end. |
1105 | this->set_size(RHSSize); |
1106 | |
1107 | RHS.clear(); |
1108 | return *this; |
1109 | } |
1110 | |
1111 | /// Storage for the SmallVector elements. This is specialized for the N=0 case |
1112 | /// to avoid allocating unnecessary storage. |
1113 | template <typename T, unsigned N> |
1114 | struct SmallVectorStorage { |
1115 | alignas(T) char InlineElts[N * sizeof(T)]; |
1116 | }; |
1117 | |
1118 | /// We need the storage to be properly aligned even for small-size of 0 so that |
1119 | /// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is |
1120 | /// well-defined. |
1121 | template <typename T> struct alignas(T) SmallVectorStorage<T, 0> {}; |
1122 | |
1123 | /// Forward declaration of SmallVector so that |
1124 | /// calculateSmallVectorDefaultInlinedElements can reference |
1125 | /// `sizeof(SmallVector<T, 0>)`. |
1126 | template <typename T, unsigned N> class LLVM_GSL_OWNER SmallVector; |
1127 | |
1128 | /// Helper class for calculating the default number of inline elements for |
1129 | /// `SmallVector<T>`. |
1130 | /// |
1131 | /// This should be migrated to a constexpr function when our minimum |
1132 | /// compiler support is enough for multi-statement constexpr functions. |
1133 | template <typename T> struct CalculateSmallVectorDefaultInlinedElements { |
1134 | // Parameter controlling the default number of inlined elements |
1135 | // for `SmallVector<T>`. |
1136 | // |
1137 | // The default number of inlined elements ensures that |
1138 | // 1. There is at least one inlined element. |
1139 | // 2. `sizeof(SmallVector<T>) <= kPreferredSmallVectorSizeof` unless |
1140 | // it contradicts 1. |
1141 | static constexpr size_t kPreferredSmallVectorSizeof = 64; |
1142 | |
1143 | // static_assert that sizeof(T) is not "too big". |
1144 | // |
1145 | // Because our policy guarantees at least one inlined element, it is possible |
1146 | // for an arbitrarily large inlined element to allocate an arbitrarily large |
1147 | // amount of inline storage. We generally consider it an antipattern for a |
1148 | // SmallVector to allocate an excessive amount of inline storage, so we want |
1149 | // to call attention to these cases and make sure that users are making an |
1150 | // intentional decision if they request a lot of inline storage. |
1151 | // |
1152 | // We want this assertion to trigger in pathological cases, but otherwise |
1153 | // not be too easy to hit. To accomplish that, the cutoff is actually somewhat |
1154 | // larger than kPreferredSmallVectorSizeof (otherwise, |
1155 | // `SmallVector<SmallVector<T>>` would be one easy way to trip it, and that |
1156 | // pattern seems useful in practice). |
1157 | // |
1158 | // One wrinkle is that this assertion is in theory non-portable, since |
1159 | // sizeof(T) is in general platform-dependent. However, we don't expect this |
1160 | // to be much of an issue, because most LLVM development happens on 64-bit |
1161 | // hosts, and therefore sizeof(T) is expected to *decrease* when compiled for |
1162 | // 32-bit hosts, dodging the issue. The reverse situation, where development |
1163 | // happens on a 32-bit host and then fails due to sizeof(T) *increasing* on a |
1164 | // 64-bit host, is expected to be very rare. |
1165 | static_assert( |
1166 | sizeof(T) <= 256, |
1167 | "You are trying to use a default number of inlined elements for " |
1168 | "`SmallVector<T>` but `sizeof(T)` is really big! Please use an " |
1169 | "explicit number of inlined elements with `SmallVector<T, N>` to make " |
1170 | "sure you really want that much inline storage." ); |
1171 | |
1172 | // Discount the size of the header itself when calculating the maximum inline |
1173 | // bytes. |
1174 | static constexpr size_t PreferredInlineBytes = |
1175 | kPreferredSmallVectorSizeof - sizeof(SmallVector<T, 0>); |
1176 | static constexpr size_t NumElementsThatFit = PreferredInlineBytes / sizeof(T); |
1177 | static constexpr size_t value = |
1178 | NumElementsThatFit == 0 ? 1 : NumElementsThatFit; |
1179 | }; |
1180 | |
1181 | /// This is a 'vector' (really, a variable-sized array), optimized |
1182 | /// for the case when the array is small. It contains some number of elements |
1183 | /// in-place, which allows it to avoid heap allocation when the actual number of |
1184 | /// elements is below that threshold. This allows normal "small" cases to be |
1185 | /// fast without losing generality for large inputs. |
1186 | /// |
1187 | /// \note |
1188 | /// In the absence of a well-motivated choice for the number of inlined |
1189 | /// elements \p N, it is recommended to use \c SmallVector<T> (that is, |
1190 | /// omitting the \p N). This will choose a default number of inlined elements |
1191 | /// reasonable for allocation on the stack (for example, trying to keep \c |
1192 | /// sizeof(SmallVector<T>) around 64 bytes). |
1193 | /// |
1194 | /// \warning This does not attempt to be exception safe. |
1195 | /// |
1196 | /// \see https://llvm.org/docs/ProgrammersManual.html#llvm-adt-smallvector-h |
1197 | template <typename T, |
1198 | unsigned N = CalculateSmallVectorDefaultInlinedElements<T>::value> |
1199 | class LLVM_GSL_OWNER SmallVector : public SmallVectorImpl<T>, |
1200 | SmallVectorStorage<T, N> { |
1201 | public: |
1202 | SmallVector() : SmallVectorImpl<T>(N) {} |
1203 | |
1204 | ~SmallVector() { |
1205 | // Destroy the constructed elements in the vector. |
1206 | this->destroy_range(this->begin(), this->end()); |
1207 | } |
1208 | |
1209 | explicit SmallVector(size_t Size) |
1210 | : SmallVectorImpl<T>(N) { |
1211 | this->resize(Size); |
1212 | } |
1213 | |
1214 | SmallVector(size_t Size, const T &Value) |
1215 | : SmallVectorImpl<T>(N) { |
1216 | this->assign(Size, Value); |
1217 | } |
1218 | |
1219 | template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>> |
1220 | SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) { |
1221 | this->append(S, E); |
1222 | } |
1223 | |
1224 | template <typename RangeTy> |
1225 | explicit SmallVector(const iterator_range<RangeTy> &R) |
1226 | : SmallVectorImpl<T>(N) { |
1227 | this->append(R.begin(), R.end()); |
1228 | } |
1229 | |
1230 | SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) { |
1231 | this->append(IL); |
1232 | } |
1233 | |
1234 | template <typename U, |
1235 | typename = std::enable_if_t<std::is_convertible<U, T>::value>> |
1236 | explicit SmallVector(ArrayRef<U> A) : SmallVectorImpl<T>(N) { |
1237 | this->append(A.begin(), A.end()); |
1238 | } |
1239 | |
1240 | SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) { |
1241 | if (!RHS.empty()) |
1242 | SmallVectorImpl<T>::operator=(RHS); |
1243 | } |
1244 | |
1245 | SmallVector &operator=(const SmallVector &RHS) { |
1246 | SmallVectorImpl<T>::operator=(RHS); |
1247 | return *this; |
1248 | } |
1249 | |
1250 | SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) { |
1251 | if (!RHS.empty()) |
1252 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
1253 | } |
1254 | |
1255 | SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) { |
1256 | if (!RHS.empty()) |
1257 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
1258 | } |
1259 | |
1260 | SmallVector &operator=(SmallVector &&RHS) { |
1261 | if (N) { |
1262 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
1263 | return *this; |
1264 | } |
1265 | // SmallVectorImpl<T>::operator= does not leverage N==0. Optimize the |
1266 | // case. |
1267 | if (this == &RHS) |
1268 | return *this; |
1269 | if (RHS.empty()) { |
1270 | this->destroy_range(this->begin(), this->end()); |
1271 | this->Size = 0; |
1272 | } else { |
1273 | this->assignRemote(std::move(RHS)); |
1274 | } |
1275 | return *this; |
1276 | } |
1277 | |
1278 | SmallVector &operator=(SmallVectorImpl<T> &&RHS) { |
1279 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
1280 | return *this; |
1281 | } |
1282 | |
1283 | SmallVector &operator=(std::initializer_list<T> IL) { |
1284 | this->assign(IL); |
1285 | return *this; |
1286 | } |
1287 | }; |
1288 | |
1289 | template <typename T, unsigned N> |
1290 | inline size_t capacity_in_bytes(const SmallVector<T, N> &X) { |
1291 | return X.capacity_in_bytes(); |
1292 | } |
1293 | |
1294 | template <typename RangeType> |
1295 | using ValueTypeFromRangeType = |
1296 | std::remove_const_t<std::remove_reference_t<decltype(*std::begin( |
1297 | std::declval<RangeType &>()))>>; |
1298 | |
1299 | /// Given a range of type R, iterate the entire range and return a |
1300 | /// SmallVector with elements of the vector. This is useful, for example, |
1301 | /// when you want to iterate a range and then sort the results. |
1302 | template <unsigned Size, typename R> |
1303 | SmallVector<ValueTypeFromRangeType<R>, Size> to_vector(R &&Range) { |
1304 | return {std::begin(Range), std::end(Range)}; |
1305 | } |
1306 | template <typename R> |
1307 | SmallVector<ValueTypeFromRangeType<R>> to_vector(R &&Range) { |
1308 | return {std::begin(Range), std::end(Range)}; |
1309 | } |
1310 | |
1311 | template <typename Out, unsigned Size, typename R> |
1312 | SmallVector<Out, Size> to_vector_of(R &&Range) { |
1313 | return {std::begin(Range), std::end(Range)}; |
1314 | } |
1315 | |
1316 | template <typename Out, typename R> SmallVector<Out> to_vector_of(R &&Range) { |
1317 | return {std::begin(Range), std::end(Range)}; |
1318 | } |
1319 | |
1320 | // Explicit instantiations |
1321 | extern template class llvm::SmallVectorBase<uint32_t>; |
1322 | #if SIZE_MAX > UINT32_MAX |
1323 | extern template class llvm::SmallVectorBase<uint64_t>; |
1324 | #endif |
1325 | |
1326 | } // end namespace llvm |
1327 | |
1328 | namespace std { |
1329 | |
1330 | /// Implement std::swap in terms of SmallVector swap. |
1331 | template<typename T> |
1332 | inline void |
1333 | swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) { |
1334 | LHS.swap(RHS); |
1335 | } |
1336 | |
1337 | /// Implement std::swap in terms of SmallVector swap. |
1338 | template<typename T, unsigned N> |
1339 | inline void |
1340 | swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) { |
1341 | LHS.swap(RHS); |
1342 | } |
1343 | |
1344 | } // end namespace std |
1345 | |
1346 | #endif // LLVM_ADT_SMALLVECTOR_H |
1347 | |