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 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.
45template <class Size_T> class SmallVectorBase {
46protected:
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
69public:
70 size_t size() const { return Size; }
71 size_t capacity() const { return Capacity; }
72
73 LLVM_NODISCARD bool empty() const { return !Size; }
74
75protected:
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
86template <class T>
87using 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.
92template <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.
101template <typename T, typename = void>
102class 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
116protected:
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
229public:
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.
308template <typename T, bool = (is_trivially_copy_constructible<T>::value) &&
309 (is_trivially_move_constructible<T>::value) &&
310 std::is_trivially_destructible<T>::value>
311class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
312 friend class SmallVectorTemplateCommon<T>;
313
314protected:
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
399public:
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.
419template <typename T, bool TriviallyCopyable>
420void 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.
428template <typename T, bool TriviallyCopyable>
429void 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.
439template <typename T, bool TriviallyCopyable>
440void 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.
454template <typename T>
455class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
456 friend class SmallVectorTemplateCommon<T>;
457
458protected:
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
541public:
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.
553template <typename T>
554class SmallVectorImpl : public SmallVectorTemplateBase<T> {
555 using SuperClass = SmallVectorTemplateBase<T>;
556
557public:
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
563protected:
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
581public:
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
596private:
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
618public:
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
754private:
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
791public:
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
954template <typename T>
955void 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
990template <typename T>
991SmallVectorImpl<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
1038template <typename T>
1039SmallVectorImpl<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.
1096template <typename T, unsigned N>
1097struct 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.
1104template <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>)`.
1109template <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.
1116template <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
1180template <typename T,
1181 unsigned N = CalculateSmallVectorDefaultInlinedElements<T>::value>
1182class LLVM_GSL_OWNER SmallVector : public SmallVectorImpl<T>,
1183 SmallVectorStorage<T, N> {
1184public:
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
1264template <typename T, unsigned N>
1265inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
1266 return X.capacity_in_bytes();
1267}
1268
1269template <typename RangeType>
1270using 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.
1277template <unsigned Size, typename R>
1278SmallVector<ValueTypeFromRangeType<R>, Size> to_vector(R &&Range) {
1279 return {std::begin(Range), std::end(Range)};
1280}
1281template <typename R>
1282SmallVector<ValueTypeFromRangeType<R>,
1283 CalculateSmallVectorDefaultInlinedElements<
1284 ValueTypeFromRangeType<R>>::value>
1285to_vector(R &&Range) {
1286 return {std::begin(Range), std::end(Range)};
1287}
1288
1289} // end namespace llvm
1290
1291namespace 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