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
33namespace llvm {
34
35template <typename T> class ArrayRef;
36
37template <typename IteratorT> class iterator_range;
38
39template <class Iterator>
40using 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.
52template <class Size_T> class SmallVectorBase {
53protected:
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(static_cast<Size_T>(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
90public:
91 size_t size() const { return Size; }
92 size_t capacity() const { return Capacity; }
93
94 [[nodiscard]] bool empty() const { return !Size; }
95
96protected:
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()); // implies no overflow in assignment
103 Size = static_cast<Size_T>(N);
104 }
105
106 /// Set the array data pointer to \p Begin and capacity to \p N.
107 ///
108 /// This does not construct or destroy any elements in the vector.
109 // This does not clean up any existing allocation.
110 void set_allocation_range(void *Begin, size_t N) {
111 assert(N <= SizeTypeMax());
112 BeginX = Begin;
113 Capacity = static_cast<Size_T>(N);
114 }
115};
116
117template <class T>
118using SmallVectorSizeType =
119 std::conditional_t<sizeof(T) < 4 && sizeof(void *) >= 8, uint64_t,
120 uint32_t>;
121
122/// Figure out the offset of the first element.
123template <class T, typename = void> struct SmallVectorAlignmentAndSize {
124 alignas(SmallVectorBase<SmallVectorSizeType<T>>) char Base[sizeof(
125 SmallVectorBase<SmallVectorSizeType<T>>)];
126 alignas(T) char FirstEl[sizeof(T)];
127};
128
129/// This is the part of SmallVectorTemplateBase which does not depend on whether
130/// the type T is a POD. The extra dummy template argument is used by ArrayRef
131/// to avoid unnecessarily requiring T to be complete.
132template <typename T, typename = void>
133class SmallVectorTemplateCommon
134 : public SmallVectorBase<SmallVectorSizeType<T>> {
135 using Base = SmallVectorBase<SmallVectorSizeType<T>>;
136
137protected:
138 /// Find the address of the first element. For this pointer math to be valid
139 /// with small-size of 0 for T with lots of alignment, it's important that
140 /// SmallVectorStorage is properly-aligned even for small-size of 0.
141 void *getFirstEl() const {
142 return const_cast<void *>(reinterpret_cast<const void *>(
143 reinterpret_cast<const char *>(this) +
144 offsetof(SmallVectorAlignmentAndSize<T>, FirstEl)));
145 }
146 // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
147
148 SmallVectorTemplateCommon(size_t Size) : Base(getFirstEl(), Size) {}
149
150 void grow_pod(size_t MinSize, size_t TSize) {
151 Base::grow_pod(getFirstEl(), MinSize, TSize);
152 }
153
154 /// Return true if this is a smallvector which has not had dynamic
155 /// memory allocated for it.
156 bool isSmall() const { return this->BeginX == getFirstEl(); }
157
158 /// Put this vector in a state of being small.
159 void resetToSmall() {
160 this->BeginX = getFirstEl();
161 this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
162 }
163
164 /// Return true if V is an internal reference to the given range.
165 bool isReferenceToRange(const void *V, const void *First, const void *Last) const {
166 // Use std::less to avoid UB.
167 std::less<> LessThan;
168 return !LessThan(V, First) && LessThan(V, Last);
169 }
170
171 /// Return true if V is an internal reference to this vector.
172 bool isReferenceToStorage(const void *V) const {
173 return isReferenceToRange(V, First: this->begin(), Last: this->end());
174 }
175
176 /// Return true if First and Last form a valid (possibly empty) range in this
177 /// vector's storage.
178 bool isRangeInStorage(const void *First, const void *Last) const {
179 // Use std::less to avoid UB.
180 std::less<> LessThan;
181 return !LessThan(First, this->begin()) && !LessThan(Last, First) &&
182 !LessThan(this->end(), Last);
183 }
184
185 /// Return true unless Elt will be invalidated by resizing the vector to
186 /// NewSize.
187 bool isSafeToReferenceAfterResize(const void *Elt, size_t NewSize) {
188 // Past the end.
189 if (LLVM_LIKELY(!isReferenceToStorage(Elt)))
190 return true;
191
192 // Return false if Elt will be destroyed by shrinking.
193 if (NewSize <= this->size())
194 return Elt < this->begin() + NewSize;
195
196 // Return false if we need to grow.
197 return NewSize <= this->capacity();
198 }
199
200 /// Check whether Elt will be invalidated by resizing the vector to NewSize.
201 void assertSafeToReferenceAfterResize(const void *Elt, size_t NewSize) {
202 assert(isSafeToReferenceAfterResize(Elt, NewSize) &&
203 "Attempting to reference an element of the vector in an operation "
204 "that invalidates it");
205 }
206
207 /// Check whether Elt will be invalidated by increasing the size of the
208 /// vector by N.
209 void assertSafeToAdd(const void *Elt, size_t N = 1) {
210 this->assertSafeToReferenceAfterResize(Elt, this->size() + N);
211 }
212
213 /// Check whether any part of the range will be invalidated by clearing.
214 void assertSafeToReferenceAfterClear(const T *From, const T *To) {
215 if (From == To)
216 return;
217 this->assertSafeToReferenceAfterResize(From, 0);
218 this->assertSafeToReferenceAfterResize(To - 1, 0);
219 }
220 template <
221 class ItTy,
222 std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value,
223 bool> = false>
224 void assertSafeToReferenceAfterClear(ItTy, ItTy) {}
225
226 /// Check whether any part of the range will be invalidated by growing.
227 void assertSafeToAddRange(const T *From, const T *To) {
228 if (From == To)
229 return;
230 this->assertSafeToAdd(From, To - From);
231 this->assertSafeToAdd(To - 1, To - From);
232 }
233 template <
234 class ItTy,
235 std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value,
236 bool> = false>
237 void assertSafeToAddRange(ItTy, ItTy) {}
238
239 /// Reserve enough space to add one element, and return the updated element
240 /// pointer in case it was a reference to the storage.
241 template <class U>
242 static const T *reserveForParamAndGetAddressImpl(U *This, const T &Elt,
243 size_t N) {
244 size_t NewSize = This->size() + N;
245 if (LLVM_LIKELY(NewSize <= This->capacity()))
246 return &Elt;
247
248 bool ReferencesStorage = false;
249 int64_t Index = -1;
250 if (!U::TakesParamByValue) {
251 if (LLVM_UNLIKELY(This->isReferenceToStorage(&Elt))) {
252 ReferencesStorage = true;
253 Index = &Elt - This->begin();
254 }
255 }
256 This->grow(NewSize);
257 return ReferencesStorage ? This->begin() + Index : &Elt;
258 }
259
260public:
261 using size_type = size_t;
262 using difference_type = ptrdiff_t;
263 using value_type = T;
264 using iterator = T *;
265 using const_iterator = const T *;
266
267 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
268 using reverse_iterator = std::reverse_iterator<iterator>;
269
270 using reference = T &;
271 using const_reference = const T &;
272 using pointer = T *;
273 using const_pointer = const T *;
274
275 using Base::capacity;
276 using Base::empty;
277 using Base::size;
278
279 // forward iterator creation methods.
280 iterator begin() { return (iterator)this->BeginX; }
281 const_iterator begin() const { return (const_iterator)this->BeginX; }
282 iterator end() { return begin() + size(); }
283 const_iterator end() const { return begin() + size(); }
284
285 // reverse iterator creation methods.
286 reverse_iterator rbegin() { return reverse_iterator(end()); }
287 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
288 reverse_iterator rend() { return reverse_iterator(begin()); }
289 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
290
291 size_type size_in_bytes() const { return size() * sizeof(T); }
292 size_type max_size() const {
293 return std::min(this->SizeTypeMax(), size_type(-1) / sizeof(T));
294 }
295
296 size_t capacity_in_bytes() const { return capacity() * sizeof(T); }
297
298 /// Return a pointer to the vector's buffer, even if empty().
299 pointer data() { return pointer(begin()); }
300 /// Return a pointer to the vector's buffer, even if empty().
301 const_pointer data() const { return const_pointer(begin()); }
302
303 reference operator[](size_type idx) {
304 assert(idx < size());
305 return begin()[idx];
306 }
307 const_reference operator[](size_type idx) const {
308 assert(idx < size());
309 return begin()[idx];
310 }
311
312 reference front() {
313 assert(!empty());
314 return begin()[0];
315 }
316 const_reference front() const {
317 assert(!empty());
318 return begin()[0];
319 }
320
321 reference back() {
322 assert(!empty());
323 return end()[-1];
324 }
325 const_reference back() const {
326 assert(!empty());
327 return end()[-1];
328 }
329};
330
331/// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put
332/// method implementations that are designed to work with non-trivial T's.
333///
334/// We approximate is_trivially_copyable with trivial move/copy construction and
335/// trivial destruction. While the standard doesn't specify that you're allowed
336/// copy these types with memcpy, there is no way for the type to observe this.
337/// This catches the important case of std::pair<POD, POD>, which is not
338/// trivially assignable.
339template <typename T, bool = (std::is_trivially_copy_constructible<T>::value) &&
340 (std::is_trivially_move_constructible<T>::value) &&
341 std::is_trivially_destructible<T>::value>
342class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
343 friend class SmallVectorTemplateCommon<T>;
344
345protected:
346 static constexpr bool TakesParamByValue = false;
347 using ValueParamT = const T &;
348
349 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
350
351 static void destroy_range(T *S, T *E) {
352 while (S != E) {
353 --E;
354 E->~T();
355 }
356 }
357
358 /// Move the range [I, E) into the uninitialized memory starting with "Dest",
359 /// constructing elements as needed.
360 template<typename It1, typename It2>
361 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
362 std::uninitialized_move(I, E, Dest);
363 }
364
365 /// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
366 /// constructing elements as needed.
367 template<typename It1, typename It2>
368 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
369 std::uninitialized_copy(I, E, Dest);
370 }
371
372 /// Grow the allocated memory (without initializing new elements), doubling
373 /// the size of the allocated memory. Guarantees space for at least one more
374 /// element, or MinSize more elements if specified.
375 void grow(size_t MinSize = 0);
376
377 /// Create a new allocation big enough for \p MinSize and pass back its size
378 /// in \p NewCapacity. This is the first section of \a grow().
379 T *mallocForGrow(size_t MinSize, size_t &NewCapacity);
380
381 /// Move existing elements over to the new allocation \p NewElts, the middle
382 /// section of \a grow().
383 void moveElementsForGrow(T *NewElts);
384
385 /// Transfer ownership of the allocation, finishing up \a grow().
386 void takeAllocationForGrow(T *NewElts, size_t NewCapacity);
387
388 /// Reserve enough space to add one element, and return the updated element
389 /// pointer in case it was a reference to the storage.
390 const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) {
391 return this->reserveForParamAndGetAddressImpl(this, Elt, N);
392 }
393
394 /// Reserve enough space to add one element, and return the updated element
395 /// pointer in case it was a reference to the storage.
396 T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) {
397 return const_cast<T *>(
398 this->reserveForParamAndGetAddressImpl(this, Elt, N));
399 }
400
401 static T &&forward_value_param(T &&V) { return std::move(V); }
402 static const T &forward_value_param(const T &V) { return V; }
403
404 void growAndAssign(size_t NumElts, const T &Elt) {
405 // Grow manually in case Elt is an internal reference.
406 size_t NewCapacity;
407 T *NewElts = mallocForGrow(MinSize: NumElts, NewCapacity);
408 std::uninitialized_fill_n(NewElts, NumElts, Elt);
409 this->destroy_range(this->begin(), this->end());
410 takeAllocationForGrow(NewElts, NewCapacity);
411 this->set_size(NumElts);
412 }
413
414 template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) {
415 // Grow manually in case one of Args is an internal reference.
416 size_t NewCapacity;
417 T *NewElts = mallocForGrow(MinSize: 0, NewCapacity);
418 ::new ((void *)(NewElts + this->size())) T(std::forward<ArgTypes>(Args)...);
419 moveElementsForGrow(NewElts);
420 takeAllocationForGrow(NewElts, NewCapacity);
421 this->set_size(this->size() + 1);
422 return this->back();
423 }
424
425public:
426 void push_back(const T &Elt) {
427 const T *EltPtr = reserveForParamAndGetAddress(Elt);
428 ::new ((void *)this->end()) T(*EltPtr);
429 this->set_size(this->size() + 1);
430 }
431
432 void push_back(T &&Elt) {
433 T *EltPtr = reserveForParamAndGetAddress(Elt);
434 ::new ((void *)this->end()) T(::std::move(*EltPtr));
435 this->set_size(this->size() + 1);
436 }
437
438 void pop_back() {
439 this->set_size(this->size() - 1);
440 this->end()->~T();
441 }
442};
443
444// Define this out-of-line to dissuade the C++ compiler from inlining it.
445template <typename T, bool TriviallyCopyable>
446void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) {
447 size_t NewCapacity;
448 T *NewElts = mallocForGrow(MinSize, NewCapacity);
449 moveElementsForGrow(NewElts);
450 takeAllocationForGrow(NewElts, NewCapacity);
451}
452
453template <typename T, bool TriviallyCopyable>
454T *SmallVectorTemplateBase<T, TriviallyCopyable>::mallocForGrow(
455 size_t MinSize, size_t &NewCapacity) {
456 return static_cast<T *>(
457 SmallVectorBase<SmallVectorSizeType<T>>::mallocForGrow(
458 this->getFirstEl(), MinSize, sizeof(T), NewCapacity));
459}
460
461// Define this out-of-line to dissuade the C++ compiler from inlining it.
462template <typename T, bool TriviallyCopyable>
463void SmallVectorTemplateBase<T, TriviallyCopyable>::moveElementsForGrow(
464 T *NewElts) {
465 // Move the elements over.
466 this->uninitialized_move(this->begin(), this->end(), NewElts);
467
468 // Destroy the original elements.
469 destroy_range(S: this->begin(), E: this->end());
470}
471
472// Define this out-of-line to dissuade the C++ compiler from inlining it.
473template <typename T, bool TriviallyCopyable>
474void SmallVectorTemplateBase<T, TriviallyCopyable>::takeAllocationForGrow(
475 T *NewElts, size_t NewCapacity) {
476 // If this wasn't grown from the inline copy, deallocate the old space.
477 if (!this->isSmall())
478 free(this->begin());
479
480 this->set_allocation_range(NewElts, NewCapacity);
481}
482
483/// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put
484/// method implementations that are designed to work with trivially copyable
485/// T's. This allows using memcpy in place of copy/move construction and
486/// skipping destruction.
487template <typename T>
488class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
489 friend class SmallVectorTemplateCommon<T>;
490
491protected:
492 /// True if it's cheap enough to take parameters by value. Doing so avoids
493 /// overhead related to mitigations for reference invalidation.
494 static constexpr bool TakesParamByValue = sizeof(T) <= 2 * sizeof(void *);
495
496 /// Either const T& or T, depending on whether it's cheap enough to take
497 /// parameters by value.
498 using ValueParamT = std::conditional_t<TakesParamByValue, T, const T &>;
499
500 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
501
502 // No need to do a destroy loop for POD's.
503 static void destroy_range(T *, T *) {}
504
505 /// Move the range [I, E) onto the uninitialized memory
506 /// starting with "Dest", constructing elements into it as needed.
507 template<typename It1, typename It2>
508 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
509 // Just do a copy.
510 uninitialized_copy(I, E, Dest);
511 }
512
513 /// Copy the range [I, E) onto the uninitialized memory
514 /// starting with "Dest", constructing elements into it as needed.
515 template<typename It1, typename It2>
516 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
517 // Arbitrary iterator types; just use the basic implementation.
518 std::uninitialized_copy(I, E, Dest);
519 }
520
521 /// Copy the range [I, E) onto the uninitialized memory
522 /// starting with "Dest", constructing elements into it as needed.
523 template <typename T1, typename T2>
524 static void uninitialized_copy(
525 T1 *I, T1 *E, T2 *Dest,
526 std::enable_if_t<std::is_same<std::remove_const_t<T1>, T2>::value> * =
527 nullptr) {
528 // Use memcpy for PODs iterated by pointers (which includes SmallVector
529 // iterators): std::uninitialized_copy optimizes to memmove, but we can
530 // use memcpy here. Note that I and E are iterators and thus might be
531 // invalid for memcpy if they are equal.
532 if (I != E)
533 memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T));
534 }
535
536 /// Double the size of the allocated memory, guaranteeing space for at
537 /// least one more element or MinSize if specified.
538 void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); }
539
540 /// Reserve enough space to add one element, and return the updated element
541 /// pointer in case it was a reference to the storage.
542 const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) {
543 return this->reserveForParamAndGetAddressImpl(this, Elt, N);
544 }
545
546 /// Reserve enough space to add one element, and return the updated element
547 /// pointer in case it was a reference to the storage.
548 T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) {
549 return const_cast<T *>(
550 this->reserveForParamAndGetAddressImpl(this, Elt, N));
551 }
552
553 /// Copy \p V or return a reference, depending on \a ValueParamT.
554 static ValueParamT forward_value_param(ValueParamT V) { return V; }
555
556 void growAndAssign(size_t NumElts, T Elt) {
557 // Elt has been copied in case it's an internal reference, side-stepping
558 // reference invalidation problems without losing the realloc optimization.
559 this->set_size(0);
560 this->grow(NumElts);
561 std::uninitialized_fill_n(this->begin(), NumElts, Elt);
562 this->set_size(NumElts);
563 }
564
565 template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) {
566 // Use push_back with a copy in case Args has an internal reference,
567 // side-stepping reference invalidation problems without losing the realloc
568 // optimization.
569 push_back(Elt: T(std::forward<ArgTypes>(Args)...));
570 return this->back();
571 }
572
573public:
574 void push_back(ValueParamT Elt) {
575 const T *EltPtr = reserveForParamAndGetAddress(Elt);
576 memcpy(reinterpret_cast<void *>(this->end()), EltPtr, sizeof(T));
577 this->set_size(this->size() + 1);
578 }
579
580 void pop_back() { this->set_size(this->size() - 1); }
581};
582
583/// This class consists of common code factored out of the SmallVector class to
584/// reduce code duplication based on the SmallVector 'N' template parameter.
585template <typename T>
586class SmallVectorImpl : public SmallVectorTemplateBase<T> {
587 using SuperClass = SmallVectorTemplateBase<T>;
588
589public:
590 using iterator = typename SuperClass::iterator;
591 using const_iterator = typename SuperClass::const_iterator;
592 using reference = typename SuperClass::reference;
593 using size_type = typename SuperClass::size_type;
594
595protected:
596 using SmallVectorTemplateBase<T>::TakesParamByValue;
597 using ValueParamT = typename SuperClass::ValueParamT;
598
599 // Default ctor - Initialize to empty.
600 explicit SmallVectorImpl(unsigned N)
601 : SmallVectorTemplateBase<T>(N) {}
602
603 void assignRemote(SmallVectorImpl &&RHS) {
604 this->destroy_range(this->begin(), this->end());
605 if (!this->isSmall())
606 free(this->begin());
607 this->BeginX = RHS.BeginX;
608 this->Size = RHS.Size;
609 this->Capacity = RHS.Capacity;
610 RHS.resetToSmall();
611 }
612
613 ~SmallVectorImpl() {
614 // Subclass has already destructed this vector's elements.
615 // If this wasn't grown from the inline copy, deallocate the old space.
616 if (!this->isSmall())
617 free(this->begin());
618 }
619
620public:
621 SmallVectorImpl(const SmallVectorImpl &) = delete;
622
623 void clear() {
624 this->destroy_range(this->begin(), this->end());
625 this->Size = 0;
626 }
627
628private:
629 // Make set_size() private to avoid misuse in subclasses.
630 using SuperClass::set_size;
631
632 template <bool ForOverwrite> void resizeImpl(size_type N) {
633 if (N == this->size())
634 return;
635
636 if (N < this->size()) {
637 this->truncate(N);
638 return;
639 }
640
641 this->reserve(N);
642 for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
643 if (ForOverwrite)
644 new (&*I) T;
645 else
646 new (&*I) T();
647 this->set_size(N);
648 }
649
650public:
651 void resize(size_type N) { resizeImpl<false>(N); }
652
653 /// Like resize, but \ref T is POD, the new values won't be initialized.
654 void resize_for_overwrite(size_type N) { resizeImpl<true>(N); }
655
656 /// Like resize, but requires that \p N is less than \a size().
657 void truncate(size_type N) {
658 assert(this->size() >= N && "Cannot increase size with truncate");
659 this->destroy_range(this->begin() + N, this->end());
660 this->set_size(N);
661 }
662
663 void resize(size_type N, ValueParamT NV) {
664 if (N == this->size())
665 return;
666
667 if (N < this->size()) {
668 this->truncate(N);
669 return;
670 }
671
672 // N > this->size(). Defer to append.
673 this->append(N - this->size(), NV);
674 }
675
676 void reserve(size_type N) {
677 if (this->capacity() < N)
678 this->grow(N);
679 }
680
681 void pop_back_n(size_type NumItems) {
682 assert(this->size() >= NumItems);
683 truncate(N: this->size() - NumItems);
684 }
685
686 [[nodiscard]] T pop_back_val() {
687 T Result = ::std::move(this->back());
688 this->pop_back();
689 return Result;
690 }
691
692 void swap(SmallVectorImpl &RHS);
693
694 /// Add the specified range to the end of the SmallVector.
695 template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>>
696 void append(ItTy in_start, ItTy in_end) {
697 this->assertSafeToAddRange(in_start, in_end);
698 size_type NumInputs = std::distance(in_start, in_end);
699 this->reserve(this->size() + NumInputs);
700 this->uninitialized_copy(in_start, in_end, this->end());
701 this->set_size(this->size() + NumInputs);
702 }
703
704 /// Append \p NumInputs copies of \p Elt to the end.
705 void append(size_type NumInputs, ValueParamT Elt) {
706 const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumInputs);
707 std::uninitialized_fill_n(this->end(), NumInputs, *EltPtr);
708 this->set_size(this->size() + NumInputs);
709 }
710
711 void append(std::initializer_list<T> IL) {
712 append(IL.begin(), IL.end());
713 }
714
715 void append(const SmallVectorImpl &RHS) { append(RHS.begin(), RHS.end()); }
716
717 void assign(size_type NumElts, ValueParamT Elt) {
718 // Note that Elt could be an internal reference.
719 if (NumElts > this->capacity()) {
720 this->growAndAssign(NumElts, Elt);
721 return;
722 }
723
724 // Assign over existing elements.
725 std::fill_n(this->begin(), std::min(NumElts, this->size()), Elt);
726 if (NumElts > this->size())
727 std::uninitialized_fill_n(this->end(), NumElts - this->size(), Elt);
728 else if (NumElts < this->size())
729 this->destroy_range(this->begin() + NumElts, this->end());
730 this->set_size(NumElts);
731 }
732
733 // FIXME: Consider assigning over existing elements, rather than clearing &
734 // re-initializing them - for all assign(...) variants.
735
736 template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>>
737 void assign(ItTy in_start, ItTy in_end) {
738 this->assertSafeToReferenceAfterClear(in_start, in_end);
739 clear();
740 append(in_start, in_end);
741 }
742
743 void assign(std::initializer_list<T> IL) {
744 clear();
745 append(IL);
746 }
747
748 void assign(const SmallVectorImpl &RHS) { assign(RHS.begin(), RHS.end()); }
749
750 iterator erase(const_iterator CI) {
751 // Just cast away constness because this is a non-const member function.
752 iterator I = const_cast<iterator>(CI);
753
754 assert(this->isReferenceToStorage(CI) && "Iterator to erase is out of bounds.");
755
756 iterator N = I;
757 // Shift all elts down one.
758 std::move(I+1, this->end(), I);
759 // Drop the last elt.
760 this->pop_back();
761 return(N);
762 }
763
764 iterator erase(const_iterator CS, const_iterator CE) {
765 // Just cast away constness because this is a non-const member function.
766 iterator S = const_cast<iterator>(CS);
767 iterator E = const_cast<iterator>(CE);
768
769 assert(this->isRangeInStorage(S, E) && "Range to erase is out of bounds.");
770
771 iterator N = S;
772 // Shift all elts down.
773 iterator I = std::move(E, this->end(), S);
774 // Drop the last elts.
775 this->destroy_range(I, this->end());
776 this->set_size(I - this->begin());
777 return(N);
778 }
779
780private:
781 template <class ArgType> iterator insert_one_impl(iterator I, ArgType &&Elt) {
782 // Callers ensure that ArgType is derived from T.
783 static_assert(
784 std::is_same<std::remove_const_t<std::remove_reference_t<ArgType>>,
785 T>::value,
786 "ArgType must be derived from T!");
787
788 if (I == this->end()) { // Important special case for empty vector.
789 this->push_back(::std::forward<ArgType>(Elt));
790 return this->end()-1;
791 }
792
793 assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.");
794
795 // Grow if necessary.
796 size_t Index = I - this->begin();
797 std::remove_reference_t<ArgType> *EltPtr =
798 this->reserveForParamAndGetAddress(Elt);
799 I = this->begin() + Index;
800
801 ::new ((void*) this->end()) T(::std::move(this->back()));
802 // Push everything else over.
803 std::move_backward(I, this->end()-1, this->end());
804 this->set_size(this->size() + 1);
805
806 // If we just moved the element we're inserting, be sure to update
807 // the reference (never happens if TakesParamByValue).
808 static_assert(!TakesParamByValue || std::is_same<ArgType, T>::value,
809 "ArgType must be 'T' when taking by value!");
810 if (!TakesParamByValue && this->isReferenceToRange(EltPtr, I, this->end()))
811 ++EltPtr;
812
813 *I = ::std::forward<ArgType>(*EltPtr);
814 return I;
815 }
816
817public:
818 iterator insert(iterator I, T &&Elt) {
819 return insert_one_impl(I, this->forward_value_param(std::move(Elt)));
820 }
821
822 iterator insert(iterator I, const T &Elt) {
823 return insert_one_impl(I, this->forward_value_param(Elt));
824 }
825
826 iterator insert(iterator I, size_type NumToInsert, ValueParamT Elt) {
827 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
828 size_t InsertElt = I - this->begin();
829
830 if (I == this->end()) { // Important special case for empty vector.
831 append(NumToInsert, Elt);
832 return this->begin()+InsertElt;
833 }
834
835 assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.");
836
837 // Ensure there is enough space, and get the (maybe updated) address of
838 // Elt.
839 const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumToInsert);
840
841 // Uninvalidate the iterator.
842 I = this->begin()+InsertElt;
843
844 // If there are more elements between the insertion point and the end of the
845 // range than there are being inserted, we can use a simple approach to
846 // insertion. Since we already reserved space, we know that this won't
847 // reallocate the vector.
848 if (size_t(this->end()-I) >= NumToInsert) {
849 T *OldEnd = this->end();
850 append(std::move_iterator<iterator>(this->end() - NumToInsert),
851 std::move_iterator<iterator>(this->end()));
852
853 // Copy the existing elements that get replaced.
854 std::move_backward(I, OldEnd-NumToInsert, OldEnd);
855
856 // If we just moved the element we're inserting, be sure to update
857 // the reference (never happens if TakesParamByValue).
858 if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end())
859 EltPtr += NumToInsert;
860
861 std::fill_n(I, NumToInsert, *EltPtr);
862 return I;
863 }
864
865 // Otherwise, we're inserting more elements than exist already, and we're
866 // not inserting at the end.
867
868 // Move over the elements that we're about to overwrite.
869 T *OldEnd = this->end();
870 this->set_size(this->size() + NumToInsert);
871 size_t NumOverwritten = OldEnd-I;
872 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
873
874 // If we just moved the element we're inserting, be sure to update
875 // the reference (never happens if TakesParamByValue).
876 if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end())
877 EltPtr += NumToInsert;
878
879 // Replace the overwritten part.
880 std::fill_n(I, NumOverwritten, *EltPtr);
881
882 // Insert the non-overwritten middle part.
883 std::uninitialized_fill_n(OldEnd, NumToInsert - NumOverwritten, *EltPtr);
884 return I;
885 }
886
887 template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>>
888 iterator insert(iterator I, ItTy From, ItTy To) {
889 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
890 size_t InsertElt = I - this->begin();
891
892 if (I == this->end()) { // Important special case for empty vector.
893 append(From, To);
894 return this->begin()+InsertElt;
895 }
896
897 assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.");
898
899 // Check that the reserve that follows doesn't invalidate the iterators.
900 this->assertSafeToAddRange(From, To);
901
902 size_t NumToInsert = std::distance(From, To);
903
904 // Ensure there is enough space.
905 reserve(N: this->size() + NumToInsert);
906
907 // Uninvalidate the iterator.
908 I = this->begin()+InsertElt;
909
910 // If there are more elements between the insertion point and the end of the
911 // range than there are being inserted, we can use a simple approach to
912 // insertion. Since we already reserved space, we know that this won't
913 // reallocate the vector.
914 if (size_t(this->end()-I) >= NumToInsert) {
915 T *OldEnd = this->end();
916 append(std::move_iterator<iterator>(this->end() - NumToInsert),
917 std::move_iterator<iterator>(this->end()));
918
919 // Copy the existing elements that get replaced.
920 std::move_backward(I, OldEnd-NumToInsert, OldEnd);
921
922 std::copy(From, To, I);
923 return I;
924 }
925
926 // Otherwise, we're inserting more elements than exist already, and we're
927 // not inserting at the end.
928
929 // Move over the elements that we're about to overwrite.
930 T *OldEnd = this->end();
931 this->set_size(this->size() + NumToInsert);
932 size_t NumOverwritten = OldEnd-I;
933 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
934
935 // Replace the overwritten part.
936 for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
937 *J = *From;
938 ++J; ++From;
939 }
940
941 // Insert the non-overwritten middle part.
942 this->uninitialized_copy(From, To, OldEnd);
943 return I;
944 }
945
946 void insert(iterator I, std::initializer_list<T> IL) {
947 insert(I, IL.begin(), IL.end());
948 }
949
950 template <typename... ArgTypes> reference emplace_back(ArgTypes &&... Args) {
951 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
952 return this->growAndEmplaceBack(std::forward<ArgTypes>(Args)...);
953
954 ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
955 this->set_size(this->size() + 1);
956 return this->back();
957 }
958
959 SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
960
961 SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
962
963 bool operator==(const SmallVectorImpl &RHS) const {
964 if (this->size() != RHS.size()) return false;
965 return std::equal(this->begin(), this->end(), RHS.begin());
966 }
967 bool operator!=(const SmallVectorImpl &RHS) const {
968 return !(*this == RHS);
969 }
970
971 bool operator<(const SmallVectorImpl &RHS) const {
972 return std::lexicographical_compare(this->begin(), this->end(),
973 RHS.begin(), RHS.end());
974 }
975 bool operator>(const SmallVectorImpl &RHS) const { return RHS < *this; }
976 bool operator<=(const SmallVectorImpl &RHS) const { return !(*this > RHS); }
977 bool operator>=(const SmallVectorImpl &RHS) const { return !(*this < RHS); }
978};
979
980template <typename T>
981void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
982 if (this == &RHS) return;
983
984 // We can only avoid copying elements if neither vector is small.
985 if (!this->isSmall() && !RHS.isSmall()) {
986 std::swap(this->BeginX, RHS.BeginX);
987 std::swap(this->Size, RHS.Size);
988 std::swap(this->Capacity, RHS.Capacity);
989 return;
990 }
991 this->reserve(RHS.size());
992 RHS.reserve(this->size());
993
994 // Swap the shared elements.
995 size_t NumShared = this->size();
996 if (NumShared > RHS.size()) NumShared = RHS.size();
997 for (size_type i = 0; i != NumShared; ++i)
998 std::swap((*this)[i], RHS[i]);
999
1000 // Copy over the extra elts.
1001 if (this->size() > RHS.size()) {
1002 size_t EltDiff = this->size() - RHS.size();
1003 this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
1004 RHS.set_size(RHS.size() + EltDiff);
1005 this->destroy_range(this->begin()+NumShared, this->end());
1006 this->set_size(NumShared);
1007 } else if (RHS.size() > this->size()) {
1008 size_t EltDiff = RHS.size() - this->size();
1009 this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
1010 this->set_size(this->size() + EltDiff);
1011 this->destroy_range(RHS.begin()+NumShared, RHS.end());
1012 RHS.set_size(NumShared);
1013 }
1014}
1015
1016template <typename T>
1017SmallVectorImpl<T> &SmallVectorImpl<T>::
1018 operator=(const SmallVectorImpl<T> &RHS) {
1019 // Avoid self-assignment.
1020 if (this == &RHS) return *this;
1021
1022 // If we already have sufficient space, assign the common elements, then
1023 // destroy any excess.
1024 size_t RHSSize = RHS.size();
1025 size_t CurSize = this->size();
1026 if (CurSize >= RHSSize) {
1027 // Assign common elements.
1028 iterator NewEnd;
1029 if (RHSSize)
1030 NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
1031 else
1032 NewEnd = this->begin();
1033
1034 // Destroy excess elements.
1035 this->destroy_range(NewEnd, this->end());
1036
1037 // Trim.
1038 this->set_size(RHSSize);
1039 return *this;
1040 }
1041
1042 // If we have to grow to have enough elements, destroy the current elements.
1043 // This allows us to avoid copying them during the grow.
1044 // FIXME: don't do this if they're efficiently moveable.
1045 if (this->capacity() < RHSSize) {
1046 // Destroy current elements.
1047 this->clear();
1048 CurSize = 0;
1049 this->grow(RHSSize);
1050 } else if (CurSize) {
1051 // Otherwise, use assignment for the already-constructed elements.
1052 std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
1053 }
1054
1055 // Copy construct the new elements in place.
1056 this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
1057 this->begin()+CurSize);
1058
1059 // Set end.
1060 this->set_size(RHSSize);
1061 return *this;
1062}
1063
1064template <typename T>
1065SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
1066 // Avoid self-assignment.
1067 if (this == &RHS) return *this;
1068
1069 // If the RHS isn't small, clear this vector and then steal its buffer.
1070 if (!RHS.isSmall()) {
1071 this->assignRemote(std::move(RHS));
1072 return *this;
1073 }
1074
1075 // If we already have sufficient space, assign the common elements, then
1076 // destroy any excess.
1077 size_t RHSSize = RHS.size();
1078 size_t CurSize = this->size();
1079 if (CurSize >= RHSSize) {
1080 // Assign common elements.
1081 iterator NewEnd = this->begin();
1082 if (RHSSize)
1083 NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd);
1084
1085 // Destroy excess elements and trim the bounds.
1086 this->destroy_range(NewEnd, this->end());
1087 this->set_size(RHSSize);
1088
1089 // Clear the RHS.
1090 RHS.clear();
1091
1092 return *this;
1093 }
1094
1095 // If we have to grow to have enough elements, destroy the current elements.
1096 // This allows us to avoid copying them during the grow.
1097 // FIXME: this may not actually make any sense if we can efficiently move
1098 // elements.
1099 if (this->capacity() < RHSSize) {
1100 // Destroy current elements.
1101 this->clear();
1102 CurSize = 0;
1103 this->grow(RHSSize);
1104 } else if (CurSize) {
1105 // Otherwise, use assignment for the already-constructed elements.
1106 std::move(RHS.begin(), RHS.begin()+CurSize, this->begin());
1107 }
1108
1109 // Move-construct the new elements in place.
1110 this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
1111 this->begin()+CurSize);
1112
1113 // Set end.
1114 this->set_size(RHSSize);
1115
1116 RHS.clear();
1117 return *this;
1118}
1119
1120/// Storage for the SmallVector elements. This is specialized for the N=0 case
1121/// to avoid allocating unnecessary storage.
1122template <typename T, unsigned N>
1123struct SmallVectorStorage {
1124 alignas(T) char InlineElts[N * sizeof(T)];
1125};
1126
1127/// We need the storage to be properly aligned even for small-size of 0 so that
1128/// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is
1129/// well-defined.
1130template <typename T> struct alignas(T) SmallVectorStorage<T, 0> {};
1131
1132/// Forward declaration of SmallVector so that
1133/// calculateSmallVectorDefaultInlinedElements can reference
1134/// `sizeof(SmallVector<T, 0>)`.
1135template <typename T, unsigned N> class LLVM_GSL_OWNER SmallVector;
1136
1137/// Helper class for calculating the default number of inline elements for
1138/// `SmallVector<T>`.
1139///
1140/// This should be migrated to a constexpr function when our minimum
1141/// compiler support is enough for multi-statement constexpr functions.
1142template <typename T> struct CalculateSmallVectorDefaultInlinedElements {
1143 // Parameter controlling the default number of inlined elements
1144 // for `SmallVector<T>`.
1145 //
1146 // The default number of inlined elements ensures that
1147 // 1. There is at least one inlined element.
1148 // 2. `sizeof(SmallVector<T>) <= kPreferredSmallVectorSizeof` unless
1149 // it contradicts 1.
1150 static constexpr size_t kPreferredSmallVectorSizeof = 64;
1151
1152 // static_assert that sizeof(T) is not "too big".
1153 //
1154 // Because our policy guarantees at least one inlined element, it is possible
1155 // for an arbitrarily large inlined element to allocate an arbitrarily large
1156 // amount of inline storage. We generally consider it an antipattern for a
1157 // SmallVector to allocate an excessive amount of inline storage, so we want
1158 // to call attention to these cases and make sure that users are making an
1159 // intentional decision if they request a lot of inline storage.
1160 //
1161 // We want this assertion to trigger in pathological cases, but otherwise
1162 // not be too easy to hit. To accomplish that, the cutoff is actually somewhat
1163 // larger than kPreferredSmallVectorSizeof (otherwise,
1164 // `SmallVector<SmallVector<T>>` would be one easy way to trip it, and that
1165 // pattern seems useful in practice).
1166 //
1167 // One wrinkle is that this assertion is in theory non-portable, since
1168 // sizeof(T) is in general platform-dependent. However, we don't expect this
1169 // to be much of an issue, because most LLVM development happens on 64-bit
1170 // hosts, and therefore sizeof(T) is expected to *decrease* when compiled for
1171 // 32-bit hosts, dodging the issue. The reverse situation, where development
1172 // happens on a 32-bit host and then fails due to sizeof(T) *increasing* on a
1173 // 64-bit host, is expected to be very rare.
1174 static_assert(
1175 sizeof(T) <= 256,
1176 "You are trying to use a default number of inlined elements for "
1177 "`SmallVector<T>` but `sizeof(T)` is really big! Please use an "
1178 "explicit number of inlined elements with `SmallVector<T, N>` to make "
1179 "sure you really want that much inline storage.");
1180
1181 // Discount the size of the header itself when calculating the maximum inline
1182 // bytes.
1183 static constexpr size_t PreferredInlineBytes =
1184 kPreferredSmallVectorSizeof - sizeof(SmallVector<T, 0>);
1185 static constexpr size_t NumElementsThatFit = PreferredInlineBytes / sizeof(T);
1186 static constexpr size_t value =
1187 NumElementsThatFit == 0 ? 1 : NumElementsThatFit;
1188};
1189
1190/// This is a 'vector' (really, a variable-sized array), optimized
1191/// for the case when the array is small. It contains some number of elements
1192/// in-place, which allows it to avoid heap allocation when the actual number of
1193/// elements is below that threshold. This allows normal "small" cases to be
1194/// fast without losing generality for large inputs.
1195///
1196/// \note
1197/// In the absence of a well-motivated choice for the number of inlined
1198/// elements \p N, it is recommended to use \c SmallVector<T> (that is,
1199/// omitting the \p N). This will choose a default number of inlined elements
1200/// reasonable for allocation on the stack (for example, trying to keep \c
1201/// sizeof(SmallVector<T>) around 64 bytes).
1202///
1203/// \warning This does not attempt to be exception safe.
1204///
1205/// \see https://llvm.org/docs/ProgrammersManual.html#llvm-adt-smallvector-h
1206template <typename T,
1207 unsigned N = CalculateSmallVectorDefaultInlinedElements<T>::value>
1208class LLVM_GSL_OWNER SmallVector : public SmallVectorImpl<T>,
1209 SmallVectorStorage<T, N> {
1210public:
1211 SmallVector() : SmallVectorImpl<T>(N) {}
1212
1213 ~SmallVector() {
1214 // Destroy the constructed elements in the vector.
1215 this->destroy_range(this->begin(), this->end());
1216 }
1217
1218 explicit SmallVector(size_t Size)
1219 : SmallVectorImpl<T>(N) {
1220 this->resize(Size);
1221 }
1222
1223 SmallVector(size_t Size, const T &Value)
1224 : SmallVectorImpl<T>(N) {
1225 this->assign(Size, Value);
1226 }
1227
1228 template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>>
1229 SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
1230 this->append(S, E);
1231 }
1232
1233 template <typename RangeTy>
1234 explicit SmallVector(const iterator_range<RangeTy> &R)
1235 : SmallVectorImpl<T>(N) {
1236 this->append(R.begin(), R.end());
1237 }
1238
1239 SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) {
1240 this->append(IL);
1241 }
1242
1243 template <typename U,
1244 typename = std::enable_if_t<std::is_convertible<U, T>::value>>
1245 explicit SmallVector(ArrayRef<U> A) : SmallVectorImpl<T>(N) {
1246 this->append(A.begin(), A.end());
1247 }
1248
1249 SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
1250 if (!RHS.empty())
1251 SmallVectorImpl<T>::operator=(RHS);
1252 }
1253
1254 SmallVector &operator=(const SmallVector &RHS) {
1255 SmallVectorImpl<T>::operator=(RHS);
1256 return *this;
1257 }
1258
1259 SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
1260 if (!RHS.empty())
1261 SmallVectorImpl<T>::operator=(::std::move(RHS));
1262 }
1263
1264 SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
1265 if (!RHS.empty())
1266 SmallVectorImpl<T>::operator=(::std::move(RHS));
1267 }
1268
1269 SmallVector &operator=(SmallVector &&RHS) {
1270 if (N) {
1271 SmallVectorImpl<T>::operator=(::std::move(RHS));
1272 return *this;
1273 }
1274 // SmallVectorImpl<T>::operator= does not leverage N==0. Optimize the
1275 // case.
1276 if (this == &RHS)
1277 return *this;
1278 if (RHS.empty()) {
1279 this->destroy_range(this->begin(), this->end());
1280 this->Size = 0;
1281 } else {
1282 this->assignRemote(std::move(RHS));
1283 }
1284 return *this;
1285 }
1286
1287 SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
1288 SmallVectorImpl<T>::operator=(::std::move(RHS));
1289 return *this;
1290 }
1291
1292 SmallVector &operator=(std::initializer_list<T> IL) {
1293 this->assign(IL);
1294 return *this;
1295 }
1296};
1297
1298template <typename T, unsigned N>
1299inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
1300 return X.capacity_in_bytes();
1301}
1302
1303template <typename RangeType>
1304using ValueTypeFromRangeType =
1305 std::remove_const_t<std::remove_reference_t<decltype(*std::begin(
1306 std::declval<RangeType &>()))>>;
1307
1308/// Given a range of type R, iterate the entire range and return a
1309/// SmallVector with elements of the vector. This is useful, for example,
1310/// when you want to iterate a range and then sort the results.
1311template <unsigned Size, typename R>
1312SmallVector<ValueTypeFromRangeType<R>, Size> to_vector(R &&Range) {
1313 return {std::begin(Range), std::end(Range)};
1314}
1315template <typename R>
1316SmallVector<ValueTypeFromRangeType<R>> to_vector(R &&Range) {
1317 return {std::begin(Range), std::end(Range)};
1318}
1319
1320template <typename Out, unsigned Size, typename R>
1321SmallVector<Out, Size> to_vector_of(R &&Range) {
1322 return {std::begin(Range), std::end(Range)};
1323}
1324
1325template <typename Out, typename R> SmallVector<Out> to_vector_of(R &&Range) {
1326 return {std::begin(Range), std::end(Range)};
1327}
1328
1329// Explicit instantiations
1330extern template class llvm::SmallVectorBase<uint32_t>;
1331#if SIZE_MAX > UINT32_MAX
1332extern template class llvm::SmallVectorBase<uint64_t>;
1333#endif
1334
1335} // end namespace llvm
1336
1337namespace std {
1338
1339 /// Implement std::swap in terms of SmallVector swap.
1340 template<typename T>
1341 inline void
1342 swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
1343 LHS.swap(RHS);
1344 }
1345
1346 /// Implement std::swap in terms of SmallVector swap.
1347 template<typename T, unsigned N>
1348 inline void
1349 swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {
1350 LHS.swap(RHS);
1351 }
1352
1353} // end namespace std
1354
1355#endif // LLVM_ADT_SMALLVECTOR_H
1356

source code of llvm/include/llvm/ADT/SmallVector.h