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