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/ADT/DenseMapInfo.h"
18#include "llvm/Support/Compiler.h"
19#include <algorithm>
20#include <cassert>
21#include <cstddef>
22#include <cstdint>
23#include <cstdlib>
24#include <cstring>
25#include <functional>
26#include <initializer_list>
27#include <iterator>
28#include <limits>
29#include <memory>
30#include <new>
31#include <type_traits>
32#include <utility>
33
34namespace llvm {
35
36template <typename T> class ArrayRef;
37
38template <typename IteratorT> class iterator_range;
39
40template <class Iterator>
41using EnableIfConvertibleToInputIterator = std::enable_if_t<std::is_convertible<
42 typename std::iterator_traits<Iterator>::iterator_category,
43 std::input_iterator_tag>::value>;
44
45/// This is all the stuff common to all SmallVectors.
46///
47/// The template parameter specifies the type which should be used to hold the
48/// Size and Capacity of the SmallVector, so it can be adjusted.
49/// Using 32 bit size is desirable to shrink the size of the SmallVector.
50/// Using 64 bit size is desirable for cases like SmallVector<char>, where a
51/// 32 bit size would limit the vector to ~4GB. SmallVectors are used for
52/// buffering bitcode output - which can exceed 4GB.
53template <class Size_T> class SmallVectorBase {
54protected:
55 void *BeginX;
56 Size_T Size = 0, Capacity;
57
58 /// The maximum value of the Size_T used.
59 static constexpr size_t SizeTypeMax() {
60 return std::numeric_limits<Size_T>::max();
61 }
62
63 SmallVectorBase() = delete;
64 SmallVectorBase(void *FirstEl, size_t TotalCapacity)
65 : BeginX(FirstEl), Capacity(static_cast<Size_T>(TotalCapacity)) {}
66
67 /// This is a helper for \a grow() that's out of line to reduce code
68 /// duplication. This function will report a fatal error if it can't grow at
69 /// least to \p MinSize.
70 LLVM_ABI void *mallocForGrow(void *FirstEl, size_t MinSize, size_t TSize,
71 size_t &NewCapacity);
72
73 /// This is an implementation of the grow() method which only works
74 /// on POD-like data types and is out of line to reduce code duplication.
75 /// This function will report a fatal error if it cannot increase capacity.
76 LLVM_ABI void grow_pod(void *FirstEl, size_t MinSize, size_t TSize);
77
78public:
79 size_t size() const { return Size; }
80 size_t capacity() const { return Capacity; }
81
82 [[nodiscard]] bool empty() const { return !Size; }
83
84protected:
85 /// Set the array size to \p N, which the current array must have enough
86 /// capacity for.
87 ///
88 /// This does not construct or destroy any elements in the vector.
89 void set_size(size_t N) {
90 assert(N <= capacity()); // implies no overflow in assignment
91 Size = static_cast<Size_T>(N);
92 }
93
94 /// Set the array data pointer to \p Begin and capacity to \p N.
95 ///
96 /// This does not construct or destroy any elements in the vector.
97 // This does not clean up any existing allocation.
98 void set_allocation_range(void *Begin, size_t N) {
99 assert(N <= SizeTypeMax());
100 BeginX = Begin;
101 Capacity = static_cast<Size_T>(N);
102 }
103};
104
105template <class T>
106using SmallVectorSizeType =
107 std::conditional_t<sizeof(T) < 4 && sizeof(void *) >= 8, uint64_t,
108 uint32_t>;
109
110/// Figure out the offset of the first element.
111template <class T, typename = void> struct SmallVectorAlignmentAndSize {
112 alignas(SmallVectorBase<SmallVectorSizeType<T>>) char Base[sizeof(
113 SmallVectorBase<SmallVectorSizeType<T>>)];
114 alignas(T) char FirstEl[sizeof(T)];
115};
116
117/// This is the part of SmallVectorTemplateBase which does not depend on whether
118/// the type T is a POD. The extra dummy template argument is used by ArrayRef
119/// to avoid unnecessarily requiring T to be complete.
120template <typename T, typename = void>
121class SmallVectorTemplateCommon
122 : public SmallVectorBase<SmallVectorSizeType<T>> {
123 using Base = SmallVectorBase<SmallVectorSizeType<T>>;
124
125protected:
126 /// Find the address of the first element. For this pointer math to be valid
127 /// with small-size of 0 for T with lots of alignment, it's important that
128 /// SmallVectorStorage is properly-aligned even for small-size of 0.
129 void *getFirstEl() const {
130 return const_cast<void *>(reinterpret_cast<const void *>(
131 reinterpret_cast<const char *>(this) +
132 offsetof(SmallVectorAlignmentAndSize<T>, FirstEl)));
133 }
134 // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
135
136 SmallVectorTemplateCommon(size_t Size) : Base(getFirstEl(), Size) {}
137
138 void grow_pod(size_t MinSize, size_t TSize) {
139 Base::grow_pod(getFirstEl(), MinSize, TSize);
140 }
141
142 /// Return true if this is a smallvector which has not had dynamic
143 /// memory allocated for it.
144 bool isSmall() const { return this->BeginX == getFirstEl(); }
145
146 /// Put this vector in a state of being small.
147 void resetToSmall() {
148 this->BeginX = getFirstEl();
149 this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
150 }
151
152 /// Return true if V is an internal reference to the given range.
153 bool isReferenceToRange(const void *V, const void *First, const void *Last) const {
154 // Use std::less to avoid UB.
155 std::less<> LessThan;
156 return !LessThan(V, First) && LessThan(V, Last);
157 }
158
159 /// Return true if V is an internal reference to this vector.
160 bool isReferenceToStorage(const void *V) const {
161 return isReferenceToRange(V, First: this->begin(), Last: this->end());
162 }
163
164 /// Return true if First and Last form a valid (possibly empty) range in this
165 /// vector's storage.
166 bool isRangeInStorage(const void *First, const void *Last) const {
167 // Use std::less to avoid UB.
168 std::less<> LessThan;
169 return !LessThan(First, this->begin()) && !LessThan(Last, First) &&
170 !LessThan(this->end(), Last);
171 }
172
173 /// Return true unless Elt will be invalidated by resizing the vector to
174 /// NewSize.
175 bool isSafeToReferenceAfterResize(const void *Elt, size_t NewSize) {
176 // Past the end.
177 if (LLVM_LIKELY(!isReferenceToStorage(Elt)))
178 return true;
179
180 // Return false if Elt will be destroyed by shrinking.
181 if (NewSize <= this->size())
182 return Elt < this->begin() + NewSize;
183
184 // Return false if we need to grow.
185 return NewSize <= this->capacity();
186 }
187
188 /// Check whether Elt will be invalidated by resizing the vector to NewSize.
189 void assertSafeToReferenceAfterResize(const void *Elt, size_t NewSize) {
190 assert(isSafeToReferenceAfterResize(Elt, NewSize) &&
191 "Attempting to reference an element of the vector in an operation "
192 "that invalidates it");
193 }
194
195 /// Check whether Elt will be invalidated by increasing the size of the
196 /// vector by N.
197 void assertSafeToAdd(const void *Elt, size_t N = 1) {
198 this->assertSafeToReferenceAfterResize(Elt, this->size() + N);
199 }
200
201 /// Check whether any part of the range will be invalidated by clearing.
202 void assertSafeToReferenceAfterClear(const T *From, const T *To) {
203 if (From == To)
204 return;
205 this->assertSafeToReferenceAfterResize(From, 0);
206 this->assertSafeToReferenceAfterResize(To - 1, 0);
207 }
208 template <
209 class ItTy,
210 std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value,
211 bool> = false>
212 void assertSafeToReferenceAfterClear(ItTy, ItTy) {}
213
214 /// Check whether any part of the range will be invalidated by growing.
215 void assertSafeToAddRange(const T *From, const T *To) {
216 if (From == To)
217 return;
218 this->assertSafeToAdd(From, To - From);
219 this->assertSafeToAdd(To - 1, To - From);
220 }
221 template <
222 class ItTy,
223 std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value,
224 bool> = false>
225 void assertSafeToAddRange(ItTy, ItTy) {}
226
227 /// Reserve enough space to add one element, and return the updated element
228 /// pointer in case it was a reference to the storage.
229 template <class U>
230 static const T *reserveForParamAndGetAddressImpl(U *This, const T &Elt,
231 size_t N) {
232 size_t NewSize = This->size() + N;
233 if (LLVM_LIKELY(NewSize <= This->capacity()))
234 return &Elt;
235
236 bool ReferencesStorage = false;
237 int64_t Index = -1;
238 if (!U::TakesParamByValue) {
239 if (LLVM_UNLIKELY(This->isReferenceToStorage(&Elt))) {
240 ReferencesStorage = true;
241 Index = &Elt - This->begin();
242 }
243 }
244 This->grow(NewSize);
245 return ReferencesStorage ? This->begin() + Index : &Elt;
246 }
247
248public:
249 using size_type = size_t;
250 using difference_type = ptrdiff_t;
251 using value_type = T;
252 using iterator = T *;
253 using const_iterator = const T *;
254
255 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
256 using reverse_iterator = std::reverse_iterator<iterator>;
257
258 using reference = T &;
259 using const_reference = const T &;
260 using pointer = T *;
261 using const_pointer = const T *;
262
263 using Base::capacity;
264 using Base::empty;
265 using Base::size;
266
267 // forward iterator creation methods.
268 iterator begin() { return (iterator)this->BeginX; }
269 const_iterator begin() const { return (const_iterator)this->BeginX; }
270 iterator end() { return begin() + size(); }
271 const_iterator end() const { return begin() + size(); }
272
273 // reverse iterator creation methods.
274 reverse_iterator rbegin() { return reverse_iterator(end()); }
275 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
276 reverse_iterator rend() { return reverse_iterator(begin()); }
277 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
278
279 size_type size_in_bytes() const { return size() * sizeof(T); }
280 size_type max_size() const {
281 return std::min(this->SizeTypeMax(), size_type(-1) / sizeof(T));
282 }
283
284 size_t capacity_in_bytes() const { return capacity() * sizeof(T); }
285
286 /// Return a pointer to the vector's buffer, even if empty().
287 pointer data() { return pointer(begin()); }
288 /// Return a pointer to the vector's buffer, even if empty().
289 const_pointer data() const { return const_pointer(begin()); }
290
291 reference operator[](size_type idx) {
292 assert(idx < size());
293 return begin()[idx];
294 }
295 const_reference operator[](size_type idx) const {
296 assert(idx < size());
297 return begin()[idx];
298 }
299
300 reference front() {
301 assert(!empty());
302 return begin()[0];
303 }
304 const_reference front() const {
305 assert(!empty());
306 return begin()[0];
307 }
308
309 reference back() {
310 assert(!empty());
311 return end()[-1];
312 }
313 const_reference back() const {
314 assert(!empty());
315 return end()[-1];
316 }
317};
318
319/// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put
320/// method implementations that are designed to work with non-trivial T's.
321///
322/// We approximate is_trivially_copyable with trivial move/copy construction and
323/// trivial destruction. While the standard doesn't specify that you're allowed
324/// copy these types with memcpy, there is no way for the type to observe this.
325/// This catches the important case of std::pair<POD, POD>, which is not
326/// trivially assignable.
327template <typename T, bool = (std::is_trivially_copy_constructible<T>::value) &&
328 (std::is_trivially_move_constructible<T>::value) &&
329 std::is_trivially_destructible<T>::value>
330class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
331 friend class SmallVectorTemplateCommon<T>;
332
333protected:
334 static constexpr bool TakesParamByValue = false;
335 using ValueParamT = const T &;
336
337 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
338
339 static void destroy_range(T *S, T *E) {
340 while (S != E) {
341 --E;
342 E->~T();
343 }
344 }
345
346 /// Move the range [I, E) into the uninitialized memory starting with "Dest",
347 /// constructing elements as needed.
348 template<typename It1, typename It2>
349 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
350 std::uninitialized_move(I, E, Dest);
351 }
352
353 /// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
354 /// constructing elements as needed.
355 template<typename It1, typename It2>
356 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
357 std::uninitialized_copy(I, E, Dest);
358 }
359
360 /// Grow the allocated memory (without initializing new elements), doubling
361 /// the size of the allocated memory. Guarantees space for at least one more
362 /// element, or MinSize more elements if specified.
363 void grow(size_t MinSize = 0);
364
365 /// Create a new allocation big enough for \p MinSize and pass back its size
366 /// in \p NewCapacity. This is the first section of \a grow().
367 T *mallocForGrow(size_t MinSize, size_t &NewCapacity);
368
369 /// Move existing elements over to the new allocation \p NewElts, the middle
370 /// section of \a grow().
371 void moveElementsForGrow(T *NewElts);
372
373 /// Transfer ownership of the allocation, finishing up \a grow().
374 void takeAllocationForGrow(T *NewElts, size_t NewCapacity);
375
376 /// Reserve enough space to add one element, and return the updated element
377 /// pointer in case it was a reference to the storage.
378 const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) {
379 return this->reserveForParamAndGetAddressImpl(this, Elt, N);
380 }
381
382 /// Reserve enough space to add one element, and return the updated element
383 /// pointer in case it was a reference to the storage.
384 T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) {
385 return const_cast<T *>(
386 this->reserveForParamAndGetAddressImpl(this, Elt, N));
387 }
388
389 static T &&forward_value_param(T &&V) { return std::move(V); }
390 static const T &forward_value_param(const T &V) { return V; }
391
392 void growAndAssign(size_t NumElts, const T &Elt) {
393 // Grow manually in case Elt is an internal reference.
394 size_t NewCapacity;
395 T *NewElts = mallocForGrow(MinSize: NumElts, NewCapacity);
396 std::uninitialized_fill_n(NewElts, NumElts, Elt);
397 this->destroy_range(this->begin(), this->end());
398 takeAllocationForGrow(NewElts, NewCapacity);
399 this->set_size(NumElts);
400 }
401
402 template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) {
403 // Grow manually in case one of Args is an internal reference.
404 size_t NewCapacity;
405 T *NewElts = mallocForGrow(MinSize: 0, NewCapacity);
406 ::new ((void *)(NewElts + this->size())) T(std::forward<ArgTypes>(Args)...);
407 moveElementsForGrow(NewElts);
408 takeAllocationForGrow(NewElts, NewCapacity);
409 this->set_size(this->size() + 1);
410 return this->back();
411 }
412
413public:
414 void push_back(const T &Elt) {
415 const T *EltPtr = reserveForParamAndGetAddress(Elt);
416 ::new ((void *)this->end()) T(*EltPtr);
417 this->set_size(this->size() + 1);
418 }
419
420 void push_back(T &&Elt) {
421 T *EltPtr = reserveForParamAndGetAddress(Elt);
422 ::new ((void *)this->end()) T(::std::move(*EltPtr));
423 this->set_size(this->size() + 1);
424 }
425
426 void pop_back() {
427 this->set_size(this->size() - 1);
428 this->end()->~T();
429 }
430};
431
432// Define this out-of-line to dissuade the C++ compiler from inlining it.
433template <typename T, bool TriviallyCopyable>
434void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) {
435 size_t NewCapacity;
436 T *NewElts = mallocForGrow(MinSize, NewCapacity);
437 moveElementsForGrow(NewElts);
438 takeAllocationForGrow(NewElts, NewCapacity);
439}
440
441template <typename T, bool TriviallyCopyable>
442T *SmallVectorTemplateBase<T, TriviallyCopyable>::mallocForGrow(
443 size_t MinSize, size_t &NewCapacity) {
444 return static_cast<T *>(
445 SmallVectorBase<SmallVectorSizeType<T>>::mallocForGrow(
446 this->getFirstEl(), MinSize, sizeof(T), NewCapacity));
447}
448
449// Define this out-of-line to dissuade the C++ compiler from inlining it.
450template <typename T, bool TriviallyCopyable>
451void SmallVectorTemplateBase<T, TriviallyCopyable>::moveElementsForGrow(
452 T *NewElts) {
453 // Move the elements over.
454 this->uninitialized_move(this->begin(), this->end(), NewElts);
455
456 // Destroy the original elements.
457 destroy_range(S: this->begin(), E: this->end());
458}
459
460// Define this out-of-line to dissuade the C++ compiler from inlining it.
461template <typename T, bool TriviallyCopyable>
462void SmallVectorTemplateBase<T, TriviallyCopyable>::takeAllocationForGrow(
463 T *NewElts, size_t NewCapacity) {
464 // If this wasn't grown from the inline copy, deallocate the old space.
465 if (!this->isSmall())
466 free(this->begin());
467
468 this->set_allocation_range(NewElts, NewCapacity);
469}
470
471/// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put
472/// method implementations that are designed to work with trivially copyable
473/// T's. This allows using memcpy in place of copy/move construction and
474/// skipping destruction.
475template <typename T>
476class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
477 friend class SmallVectorTemplateCommon<T>;
478
479protected:
480 /// True if it's cheap enough to take parameters by value. Doing so avoids
481 /// overhead related to mitigations for reference invalidation.
482 static constexpr bool TakesParamByValue = sizeof(T) <= 2 * sizeof(void *);
483
484 /// Either const T& or T, depending on whether it's cheap enough to take
485 /// parameters by value.
486 using ValueParamT = std::conditional_t<TakesParamByValue, T, const T &>;
487
488 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
489
490 // No need to do a destroy loop for POD's.
491 static void destroy_range(T *, T *) {}
492
493 /// Move the range [I, E) onto the uninitialized memory
494 /// starting with "Dest", constructing elements into it as needed.
495 template<typename It1, typename It2>
496 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
497 // Just do a copy.
498 uninitialized_copy(I, E, Dest);
499 }
500
501 /// Copy the range [I, E) onto the uninitialized memory
502 /// starting with "Dest", constructing elements into it as needed.
503 template<typename It1, typename It2>
504 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
505 // Arbitrary iterator types; just use the basic implementation.
506 std::uninitialized_copy(I, E, Dest);
507 }
508
509 /// Copy the range [I, E) onto the uninitialized memory
510 /// starting with "Dest", constructing elements into it as needed.
511 template <typename T1, typename T2>
512 static void uninitialized_copy(
513 T1 *I, T1 *E, T2 *Dest,
514 std::enable_if_t<std::is_same<std::remove_const_t<T1>, T2>::value> * =
515 nullptr) {
516 // Use memcpy for PODs iterated by pointers (which includes SmallVector
517 // iterators): std::uninitialized_copy optimizes to memmove, but we can
518 // use memcpy here. Note that I and E are iterators and thus might be
519 // invalid for memcpy if they are equal.
520 if (I != E)
521 memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T));
522 }
523
524 /// Double the size of the allocated memory, guaranteeing space for at
525 /// least one more element or MinSize if specified.
526 void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); }
527
528 /// Reserve enough space to add one element, and return the updated element
529 /// pointer in case it was a reference to the storage.
530 const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) {
531 return this->reserveForParamAndGetAddressImpl(this, Elt, N);
532 }
533
534 /// Reserve enough space to add one element, and return the updated element
535 /// pointer in case it was a reference to the storage.
536 T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) {
537 return const_cast<T *>(
538 this->reserveForParamAndGetAddressImpl(this, Elt, N));
539 }
540
541 /// Copy \p V or return a reference, depending on \a ValueParamT.
542 static ValueParamT forward_value_param(ValueParamT V) { return V; }
543
544 void growAndAssign(size_t NumElts, T Elt) {
545 // Elt has been copied in case it's an internal reference, side-stepping
546 // reference invalidation problems without losing the realloc optimization.
547 this->set_size(0);
548 this->grow(NumElts);
549 std::uninitialized_fill_n(this->begin(), NumElts, Elt);
550 this->set_size(NumElts);
551 }
552
553 template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) {
554 // Use push_back with a copy in case Args has an internal reference,
555 // side-stepping reference invalidation problems without losing the realloc
556 // optimization.
557 push_back(Elt: T(std::forward<ArgTypes>(Args)...));
558 return this->back();
559 }
560
561public:
562 void push_back(ValueParamT Elt) {
563 const T *EltPtr = reserveForParamAndGetAddress(Elt);
564 memcpy(reinterpret_cast<void *>(this->end()), EltPtr, sizeof(T));
565 this->set_size(this->size() + 1);
566 }
567
568 void pop_back() { this->set_size(this->size() - 1); }
569};
570
571/// This class consists of common code factored out of the SmallVector class to
572/// reduce code duplication based on the SmallVector 'N' template parameter.
573template <typename T>
574class SmallVectorImpl : public SmallVectorTemplateBase<T> {
575 using SuperClass = SmallVectorTemplateBase<T>;
576
577public:
578 using iterator = typename SuperClass::iterator;
579 using const_iterator = typename SuperClass::const_iterator;
580 using reference = typename SuperClass::reference;
581 using size_type = typename SuperClass::size_type;
582
583protected:
584 using SmallVectorTemplateBase<T>::TakesParamByValue;
585 using ValueParamT = typename SuperClass::ValueParamT;
586
587 // Default ctor - Initialize to empty.
588 explicit SmallVectorImpl(unsigned N)
589 : SmallVectorTemplateBase<T>(N) {}
590
591 void assignRemote(SmallVectorImpl &&RHS) {
592 this->destroy_range(this->begin(), this->end());
593 if (!this->isSmall())
594 free(this->begin());
595 this->BeginX = RHS.BeginX;
596 this->Size = RHS.Size;
597 this->Capacity = RHS.Capacity;
598 RHS.resetToSmall();
599 }
600
601 ~SmallVectorImpl() {
602 // Subclass has already destructed this vector's elements.
603 // If this wasn't grown from the inline copy, deallocate the old space.
604 if (!this->isSmall())
605 free(this->begin());
606 }
607
608public:
609 SmallVectorImpl(const SmallVectorImpl &) = delete;
610
611 void clear() {
612 this->destroy_range(this->begin(), this->end());
613 this->Size = 0;
614 }
615
616private:
617 // Make set_size() private to avoid misuse in subclasses.
618 using SuperClass::set_size;
619
620 template <bool ForOverwrite> void resizeImpl(size_type N) {
621 if (N == this->size())
622 return;
623
624 if (N < this->size()) {
625 this->truncate(N);
626 return;
627 }
628
629 this->reserve(N);
630 for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
631 if (ForOverwrite)
632 new (&*I) T;
633 else
634 new (&*I) T();
635 this->set_size(N);
636 }
637
638public:
639 void resize(size_type N) { resizeImpl<false>(N); }
640
641 /// Like resize, but \ref T is POD, the new values won't be initialized.
642 void resize_for_overwrite(size_type N) { resizeImpl<true>(N); }
643
644 /// Like resize, but requires that \p N is less than \a size().
645 void truncate(size_type N) {
646 assert(this->size() >= N && "Cannot increase size with truncate");
647 this->destroy_range(this->begin() + N, this->end());
648 this->set_size(N);
649 }
650
651 void resize(size_type N, ValueParamT NV) {
652 if (N == this->size())
653 return;
654
655 if (N < this->size()) {
656 this->truncate(N);
657 return;
658 }
659
660 // N > this->size(). Defer to append.
661 this->append(N - this->size(), NV);
662 }
663
664 void reserve(size_type N) {
665 if (this->capacity() < N)
666 this->grow(N);
667 }
668
669 void pop_back_n(size_type NumItems) {
670 assert(this->size() >= NumItems);
671 truncate(N: this->size() - NumItems);
672 }
673
674 [[nodiscard]] T pop_back_val() {
675 T Result = ::std::move(this->back());
676 this->pop_back();
677 return Result;
678 }
679
680 void swap(SmallVectorImpl &RHS);
681
682 /// Add the specified range to the end of the SmallVector.
683 template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>>
684 void append(ItTy in_start, ItTy in_end) {
685 this->assertSafeToAddRange(in_start, in_end);
686 size_type NumInputs = std::distance(in_start, in_end);
687 this->reserve(this->size() + NumInputs);
688 this->uninitialized_copy(in_start, in_end, this->end());
689 this->set_size(this->size() + NumInputs);
690 }
691
692 /// Append \p NumInputs copies of \p Elt to the end.
693 void append(size_type NumInputs, ValueParamT Elt) {
694 const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumInputs);
695 std::uninitialized_fill_n(this->end(), NumInputs, *EltPtr);
696 this->set_size(this->size() + NumInputs);
697 }
698
699 void append(std::initializer_list<T> IL) {
700 append(IL.begin(), IL.end());
701 }
702
703 void append(const SmallVectorImpl &RHS) { append(RHS.begin(), RHS.end()); }
704
705 void assign(size_type NumElts, ValueParamT Elt) {
706 // Note that Elt could be an internal reference.
707 if (NumElts > this->capacity()) {
708 this->growAndAssign(NumElts, Elt);
709 return;
710 }
711
712 // Assign over existing elements.
713 std::fill_n(this->begin(), std::min(NumElts, this->size()), Elt);
714 if (NumElts > this->size())
715 std::uninitialized_fill_n(this->end(), NumElts - this->size(), Elt);
716 else if (NumElts < this->size())
717 this->destroy_range(this->begin() + NumElts, this->end());
718 this->set_size(NumElts);
719 }
720
721 // FIXME: Consider assigning over existing elements, rather than clearing &
722 // re-initializing them - for all assign(...) variants.
723
724 template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>>
725 void assign(ItTy in_start, ItTy in_end) {
726 this->assertSafeToReferenceAfterClear(in_start, in_end);
727 clear();
728 append(in_start, in_end);
729 }
730
731 void assign(std::initializer_list<T> IL) {
732 clear();
733 append(IL);
734 }
735
736 void assign(const SmallVectorImpl &RHS) { assign(RHS.begin(), RHS.end()); }
737
738 iterator erase(const_iterator CI) {
739 // Just cast away constness because this is a non-const member function.
740 iterator I = const_cast<iterator>(CI);
741
742 assert(this->isReferenceToStorage(CI) && "Iterator to erase is out of bounds.");
743
744 iterator N = I;
745 // Shift all elts down one.
746 std::move(I+1, this->end(), I);
747 // Drop the last elt.
748 this->pop_back();
749 return(N);
750 }
751
752 iterator erase(const_iterator CS, const_iterator CE) {
753 // Just cast away constness because this is a non-const member function.
754 iterator S = const_cast<iterator>(CS);
755 iterator E = const_cast<iterator>(CE);
756
757 assert(this->isRangeInStorage(S, E) && "Range to erase is out of bounds.");
758
759 iterator N = S;
760 // Shift all elts down.
761 iterator I = std::move(E, this->end(), S);
762 // Drop the last elts.
763 this->destroy_range(I, this->end());
764 this->set_size(I - this->begin());
765 return(N);
766 }
767
768private:
769 template <class ArgType> iterator insert_one_impl(iterator I, ArgType &&Elt) {
770 // Callers ensure that ArgType is derived from T.
771 static_assert(
772 std::is_same<std::remove_const_t<std::remove_reference_t<ArgType>>,
773 T>::value,
774 "ArgType must be derived from T!");
775
776 if (I == this->end()) { // Important special case for empty vector.
777 this->push_back(::std::forward<ArgType>(Elt));
778 return this->end()-1;
779 }
780
781 assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.");
782
783 // Grow if necessary.
784 size_t Index = I - this->begin();
785 std::remove_reference_t<ArgType> *EltPtr =
786 this->reserveForParamAndGetAddress(Elt);
787 I = this->begin() + Index;
788
789 ::new ((void*) this->end()) T(::std::move(this->back()));
790 // Push everything else over.
791 std::move_backward(I, this->end()-1, this->end());
792 this->set_size(this->size() + 1);
793
794 // If we just moved the element we're inserting, be sure to update
795 // the reference (never happens if TakesParamByValue).
796 static_assert(!TakesParamByValue || std::is_same<ArgType, T>::value,
797 "ArgType must be 'T' when taking by value!");
798 if (!TakesParamByValue && this->isReferenceToRange(EltPtr, I, this->end()))
799 ++EltPtr;
800
801 *I = ::std::forward<ArgType>(*EltPtr);
802 return I;
803 }
804
805public:
806 iterator insert(iterator I, T &&Elt) {
807 return insert_one_impl(I, this->forward_value_param(std::move(Elt)));
808 }
809
810 iterator insert(iterator I, const T &Elt) {
811 return insert_one_impl(I, this->forward_value_param(Elt));
812 }
813
814 iterator insert(iterator I, size_type NumToInsert, ValueParamT Elt) {
815 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
816 size_t InsertElt = I - this->begin();
817
818 if (I == this->end()) { // Important special case for empty vector.
819 append(NumToInsert, Elt);
820 return this->begin()+InsertElt;
821 }
822
823 assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.");
824
825 // Ensure there is enough space, and get the (maybe updated) address of
826 // Elt.
827 const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumToInsert);
828
829 // Uninvalidate the iterator.
830 I = this->begin()+InsertElt;
831
832 // If there are more elements between the insertion point and the end of the
833 // range than there are being inserted, we can use a simple approach to
834 // insertion. Since we already reserved space, we know that this won't
835 // reallocate the vector.
836 if (size_t(this->end()-I) >= NumToInsert) {
837 T *OldEnd = this->end();
838 append(std::move_iterator<iterator>(this->end() - NumToInsert),
839 std::move_iterator<iterator>(this->end()));
840
841 // Copy the existing elements that get replaced.
842 std::move_backward(I, OldEnd-NumToInsert, OldEnd);
843
844 // If we just moved the element we're inserting, be sure to update
845 // the reference (never happens if TakesParamByValue).
846 if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end())
847 EltPtr += NumToInsert;
848
849 std::fill_n(I, NumToInsert, *EltPtr);
850 return I;
851 }
852
853 // Otherwise, we're inserting more elements than exist already, and we're
854 // not inserting at the end.
855
856 // Move over the elements that we're about to overwrite.
857 T *OldEnd = this->end();
858 this->set_size(this->size() + NumToInsert);
859 size_t NumOverwritten = OldEnd-I;
860 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
861
862 // If we just moved the element we're inserting, be sure to update
863 // the reference (never happens if TakesParamByValue).
864 if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end())
865 EltPtr += NumToInsert;
866
867 // Replace the overwritten part.
868 std::fill_n(I, NumOverwritten, *EltPtr);
869
870 // Insert the non-overwritten middle part.
871 std::uninitialized_fill_n(OldEnd, NumToInsert - NumOverwritten, *EltPtr);
872 return I;
873 }
874
875 template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>>
876 iterator insert(iterator I, ItTy From, ItTy To) {
877 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
878 size_t InsertElt = I - this->begin();
879
880 if (I == this->end()) { // Important special case for empty vector.
881 append(From, To);
882 return this->begin()+InsertElt;
883 }
884
885 assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.");
886
887 // Check that the reserve that follows doesn't invalidate the iterators.
888 this->assertSafeToAddRange(From, To);
889
890 size_t NumToInsert = std::distance(From, To);
891
892 // Ensure there is enough space.
893 reserve(N: this->size() + NumToInsert);
894
895 // Uninvalidate the iterator.
896 I = this->begin()+InsertElt;
897
898 // If there are more elements between the insertion point and the end of the
899 // range than there are being inserted, we can use a simple approach to
900 // insertion. Since we already reserved space, we know that this won't
901 // reallocate the vector.
902 if (size_t(this->end()-I) >= NumToInsert) {
903 T *OldEnd = this->end();
904 append(std::move_iterator<iterator>(this->end() - NumToInsert),
905 std::move_iterator<iterator>(this->end()));
906
907 // Copy the existing elements that get replaced.
908 std::move_backward(I, OldEnd-NumToInsert, OldEnd);
909
910 std::copy(From, To, I);
911 return I;
912 }
913
914 // Otherwise, we're inserting more elements than exist already, and we're
915 // not inserting at the end.
916
917 // Move over the elements that we're about to overwrite.
918 T *OldEnd = this->end();
919 this->set_size(this->size() + NumToInsert);
920 size_t NumOverwritten = OldEnd-I;
921 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
922
923 // Replace the overwritten part.
924 for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
925 *J = *From;
926 ++J; ++From;
927 }
928
929 // Insert the non-overwritten middle part.
930 this->uninitialized_copy(From, To, OldEnd);
931 return I;
932 }
933
934 void insert(iterator I, std::initializer_list<T> IL) {
935 insert(I, IL.begin(), IL.end());
936 }
937
938 template <typename... ArgTypes> reference emplace_back(ArgTypes &&... Args) {
939 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
940 return this->growAndEmplaceBack(std::forward<ArgTypes>(Args)...);
941
942 ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
943 this->set_size(this->size() + 1);
944 return this->back();
945 }
946
947 SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
948
949 SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
950
951 bool operator==(const SmallVectorImpl &RHS) const {
952 if (this->size() != RHS.size()) return false;
953 return std::equal(this->begin(), this->end(), RHS.begin());
954 }
955 bool operator!=(const SmallVectorImpl &RHS) const {
956 return !(*this == RHS);
957 }
958
959 bool operator<(const SmallVectorImpl &RHS) const {
960 return std::lexicographical_compare(this->begin(), this->end(),
961 RHS.begin(), RHS.end());
962 }
963 bool operator>(const SmallVectorImpl &RHS) const { return RHS < *this; }
964 bool operator<=(const SmallVectorImpl &RHS) const { return !(*this > RHS); }
965 bool operator>=(const SmallVectorImpl &RHS) const { return !(*this < RHS); }
966};
967
968template <typename T>
969void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
970 if (this == &RHS) return;
971
972 // We can only avoid copying elements if neither vector is small.
973 if (!this->isSmall() && !RHS.isSmall()) {
974 std::swap(this->BeginX, RHS.BeginX);
975 std::swap(this->Size, RHS.Size);
976 std::swap(this->Capacity, RHS.Capacity);
977 return;
978 }
979 this->reserve(RHS.size());
980 RHS.reserve(this->size());
981
982 // Swap the shared elements.
983 size_t NumShared = this->size();
984 if (NumShared > RHS.size()) NumShared = RHS.size();
985 for (size_type i = 0; i != NumShared; ++i)
986 std::swap((*this)[i], RHS[i]);
987
988 // Copy over the extra elts.
989 if (this->size() > RHS.size()) {
990 size_t EltDiff = this->size() - RHS.size();
991 this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
992 RHS.set_size(RHS.size() + EltDiff);
993 this->destroy_range(this->begin()+NumShared, this->end());
994 this->set_size(NumShared);
995 } else if (RHS.size() > this->size()) {
996 size_t EltDiff = RHS.size() - this->size();
997 this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
998 this->set_size(this->size() + EltDiff);
999 this->destroy_range(RHS.begin()+NumShared, RHS.end());
1000 RHS.set_size(NumShared);
1001 }
1002}
1003
1004template <typename T>
1005SmallVectorImpl<T> &SmallVectorImpl<T>::
1006 operator=(const SmallVectorImpl<T> &RHS) {
1007 // Avoid self-assignment.
1008 if (this == &RHS) return *this;
1009
1010 // If we already have sufficient space, assign the common elements, then
1011 // destroy any excess.
1012 size_t RHSSize = RHS.size();
1013 size_t CurSize = this->size();
1014 if (CurSize >= RHSSize) {
1015 // Assign common elements.
1016 iterator NewEnd;
1017 if (RHSSize)
1018 NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
1019 else
1020 NewEnd = this->begin();
1021
1022 // Destroy excess elements.
1023 this->destroy_range(NewEnd, this->end());
1024
1025 // Trim.
1026 this->set_size(RHSSize);
1027 return *this;
1028 }
1029
1030 // If we have to grow to have enough elements, destroy the current elements.
1031 // This allows us to avoid copying them during the grow.
1032 // FIXME: don't do this if they're efficiently moveable.
1033 if (this->capacity() < RHSSize) {
1034 // Destroy current elements.
1035 this->clear();
1036 CurSize = 0;
1037 this->grow(RHSSize);
1038 } else if (CurSize) {
1039 // Otherwise, use assignment for the already-constructed elements.
1040 std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
1041 }
1042
1043 // Copy construct the new elements in place.
1044 this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
1045 this->begin()+CurSize);
1046
1047 // Set end.
1048 this->set_size(RHSSize);
1049 return *this;
1050}
1051
1052template <typename T>
1053SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
1054 // Avoid self-assignment.
1055 if (this == &RHS) return *this;
1056
1057 // If the RHS isn't small, clear this vector and then steal its buffer.
1058 if (!RHS.isSmall()) {
1059 this->assignRemote(std::move(RHS));
1060 return *this;
1061 }
1062
1063 // If we already have sufficient space, assign the common elements, then
1064 // destroy any excess.
1065 size_t RHSSize = RHS.size();
1066 size_t CurSize = this->size();
1067 if (CurSize >= RHSSize) {
1068 // Assign common elements.
1069 iterator NewEnd = this->begin();
1070 if (RHSSize)
1071 NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd);
1072
1073 // Destroy excess elements and trim the bounds.
1074 this->destroy_range(NewEnd, this->end());
1075 this->set_size(RHSSize);
1076
1077 // Clear the RHS.
1078 RHS.clear();
1079
1080 return *this;
1081 }
1082
1083 // If we have to grow to have enough elements, destroy the current elements.
1084 // This allows us to avoid copying them during the grow.
1085 // FIXME: this may not actually make any sense if we can efficiently move
1086 // elements.
1087 if (this->capacity() < RHSSize) {
1088 // Destroy current elements.
1089 this->clear();
1090 CurSize = 0;
1091 this->grow(RHSSize);
1092 } else if (CurSize) {
1093 // Otherwise, use assignment for the already-constructed elements.
1094 std::move(RHS.begin(), RHS.begin()+CurSize, this->begin());
1095 }
1096
1097 // Move-construct the new elements in place.
1098 this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
1099 this->begin()+CurSize);
1100
1101 // Set end.
1102 this->set_size(RHSSize);
1103
1104 RHS.clear();
1105 return *this;
1106}
1107
1108/// Storage for the SmallVector elements. This is specialized for the N=0 case
1109/// to avoid allocating unnecessary storage.
1110template <typename T, unsigned N>
1111struct SmallVectorStorage {
1112 alignas(T) char InlineElts[N * sizeof(T)];
1113};
1114
1115/// We need the storage to be properly aligned even for small-size of 0 so that
1116/// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is
1117/// well-defined.
1118template <typename T> struct alignas(T) SmallVectorStorage<T, 0> {};
1119
1120/// Forward declaration of SmallVector so that
1121/// calculateSmallVectorDefaultInlinedElements can reference
1122/// `sizeof(SmallVector<T, 0>)`.
1123template <typename T, unsigned N> class LLVM_GSL_OWNER SmallVector;
1124
1125/// Helper class for calculating the default number of inline elements for
1126/// `SmallVector<T>`.
1127///
1128/// This should be migrated to a constexpr function when our minimum
1129/// compiler support is enough for multi-statement constexpr functions.
1130template <typename T> struct CalculateSmallVectorDefaultInlinedElements {
1131 // Parameter controlling the default number of inlined elements
1132 // for `SmallVector<T>`.
1133 //
1134 // The default number of inlined elements ensures that
1135 // 1. There is at least one inlined element.
1136 // 2. `sizeof(SmallVector<T>) <= kPreferredSmallVectorSizeof` unless
1137 // it contradicts 1.
1138 static constexpr size_t kPreferredSmallVectorSizeof = 64;
1139
1140 // static_assert that sizeof(T) is not "too big".
1141 //
1142 // Because our policy guarantees at least one inlined element, it is possible
1143 // for an arbitrarily large inlined element to allocate an arbitrarily large
1144 // amount of inline storage. We generally consider it an antipattern for a
1145 // SmallVector to allocate an excessive amount of inline storage, so we want
1146 // to call attention to these cases and make sure that users are making an
1147 // intentional decision if they request a lot of inline storage.
1148 //
1149 // We want this assertion to trigger in pathological cases, but otherwise
1150 // not be too easy to hit. To accomplish that, the cutoff is actually somewhat
1151 // larger than kPreferredSmallVectorSizeof (otherwise,
1152 // `SmallVector<SmallVector<T>>` would be one easy way to trip it, and that
1153 // pattern seems useful in practice).
1154 //
1155 // One wrinkle is that this assertion is in theory non-portable, since
1156 // sizeof(T) is in general platform-dependent. However, we don't expect this
1157 // to be much of an issue, because most LLVM development happens on 64-bit
1158 // hosts, and therefore sizeof(T) is expected to *decrease* when compiled for
1159 // 32-bit hosts, dodging the issue. The reverse situation, where development
1160 // happens on a 32-bit host and then fails due to sizeof(T) *increasing* on a
1161 // 64-bit host, is expected to be very rare.
1162 static_assert(
1163 sizeof(T) <= 256,
1164 "You are trying to use a default number of inlined elements for "
1165 "`SmallVector<T>` but `sizeof(T)` is really big! Please use an "
1166 "explicit number of inlined elements with `SmallVector<T, N>` to make "
1167 "sure you really want that much inline storage.");
1168
1169 // Discount the size of the header itself when calculating the maximum inline
1170 // bytes.
1171 static constexpr size_t PreferredInlineBytes =
1172 kPreferredSmallVectorSizeof - sizeof(SmallVector<T, 0>);
1173 static constexpr size_t NumElementsThatFit = PreferredInlineBytes / sizeof(T);
1174 static constexpr size_t value =
1175 NumElementsThatFit == 0 ? 1 : NumElementsThatFit;
1176};
1177
1178/// This is a 'vector' (really, a variable-sized array), optimized
1179/// for the case when the array is small. It contains some number of elements
1180/// in-place, which allows it to avoid heap allocation when the actual number of
1181/// elements is below that threshold. This allows normal "small" cases to be
1182/// fast without losing generality for large inputs.
1183///
1184/// \note
1185/// In the absence of a well-motivated choice for the number of inlined
1186/// elements \p N, it is recommended to use \c SmallVector<T> (that is,
1187/// omitting the \p N). This will choose a default number of inlined elements
1188/// reasonable for allocation on the stack (for example, trying to keep \c
1189/// sizeof(SmallVector<T>) around 64 bytes).
1190///
1191/// \warning This does not attempt to be exception safe.
1192///
1193/// \see https://llvm.org/docs/ProgrammersManual.html#llvm-adt-smallvector-h
1194template <typename T,
1195 unsigned N = CalculateSmallVectorDefaultInlinedElements<T>::value>
1196class LLVM_GSL_OWNER SmallVector : public SmallVectorImpl<T>,
1197 SmallVectorStorage<T, N> {
1198public:
1199 SmallVector() : SmallVectorImpl<T>(N) {}
1200
1201 ~SmallVector() {
1202 // Destroy the constructed elements in the vector.
1203 this->destroy_range(this->begin(), this->end());
1204 }
1205
1206 explicit SmallVector(size_t Size)
1207 : SmallVectorImpl<T>(N) {
1208 this->resize(Size);
1209 }
1210
1211 SmallVector(size_t Size, const T &Value)
1212 : SmallVectorImpl<T>(N) {
1213 this->assign(Size, Value);
1214 }
1215
1216 template <typename ItTy, typename = EnableIfConvertibleToInputIterator<ItTy>>
1217 SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
1218 this->append(S, E);
1219 }
1220
1221 template <typename RangeTy>
1222 explicit SmallVector(const iterator_range<RangeTy> &R)
1223 : SmallVectorImpl<T>(N) {
1224 this->append(R.begin(), R.end());
1225 }
1226
1227 SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) {
1228 this->append(IL);
1229 }
1230
1231 template <typename U,
1232 typename = std::enable_if_t<std::is_convertible<U, T>::value>>
1233 explicit SmallVector(ArrayRef<U> A) : SmallVectorImpl<T>(N) {
1234 this->append(A.begin(), A.end());
1235 }
1236
1237 SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
1238 if (!RHS.empty())
1239 SmallVectorImpl<T>::operator=(RHS);
1240 }
1241
1242 SmallVector &operator=(const SmallVector &RHS) {
1243 SmallVectorImpl<T>::operator=(RHS);
1244 return *this;
1245 }
1246
1247 SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
1248 if (!RHS.empty())
1249 SmallVectorImpl<T>::operator=(::std::move(RHS));
1250 }
1251
1252 SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
1253 if (!RHS.empty())
1254 SmallVectorImpl<T>::operator=(::std::move(RHS));
1255 }
1256
1257 SmallVector &operator=(SmallVector &&RHS) {
1258 if (N) {
1259 SmallVectorImpl<T>::operator=(::std::move(RHS));
1260 return *this;
1261 }
1262 // SmallVectorImpl<T>::operator= does not leverage N==0. Optimize the
1263 // case.
1264 if (this == &RHS)
1265 return *this;
1266 if (RHS.empty()) {
1267 this->destroy_range(this->begin(), this->end());
1268 this->Size = 0;
1269 } else {
1270 this->assignRemote(std::move(RHS));
1271 }
1272 return *this;
1273 }
1274
1275 SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
1276 SmallVectorImpl<T>::operator=(::std::move(RHS));
1277 return *this;
1278 }
1279
1280 SmallVector &operator=(std::initializer_list<T> IL) {
1281 this->assign(IL);
1282 return *this;
1283 }
1284};
1285
1286template <typename T, unsigned N>
1287inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
1288 return X.capacity_in_bytes();
1289}
1290
1291template <typename RangeType>
1292using ValueTypeFromRangeType =
1293 std::remove_const_t<std::remove_reference_t<decltype(*std::begin(
1294 std::declval<RangeType &>()))>>;
1295
1296/// Given a range of type R, iterate the entire range and return a
1297/// SmallVector with elements of the vector. This is useful, for example,
1298/// when you want to iterate a range and then sort the results.
1299template <unsigned Size, typename R>
1300SmallVector<ValueTypeFromRangeType<R>, Size> to_vector(R &&Range) {
1301 return {std::begin(Range), std::end(Range)};
1302}
1303template <typename R>
1304SmallVector<ValueTypeFromRangeType<R>> to_vector(R &&Range) {
1305 return {std::begin(Range), std::end(Range)};
1306}
1307
1308template <typename Out, unsigned Size, typename R>
1309SmallVector<Out, Size> to_vector_of(R &&Range) {
1310 return {std::begin(Range), std::end(Range)};
1311}
1312
1313template <typename Out, typename R> SmallVector<Out> to_vector_of(R &&Range) {
1314 return {std::begin(Range), std::end(Range)};
1315}
1316
1317// Explicit instantiations
1318extern template class llvm::SmallVectorBase<uint32_t>;
1319#if SIZE_MAX > UINT32_MAX
1320extern template class llvm::SmallVectorBase<uint64_t>;
1321#endif
1322
1323// Provide DenseMapInfo for SmallVector of a type which has info.
1324template <typename T, unsigned N> struct DenseMapInfo<llvm::SmallVector<T, N>> {
1325 static SmallVector<T, N> getEmptyKey() {
1326 return {DenseMapInfo<T>::getEmptyKey()};
1327 }
1328
1329 static SmallVector<T, N> getTombstoneKey() {
1330 return {DenseMapInfo<T>::getTombstoneKey()};
1331 }
1332
1333 static unsigned getHashValue(const SmallVector<T, N> &V) {
1334 return static_cast<unsigned>(hash_combine_range(V));
1335 }
1336
1337 static bool isEqual(const SmallVector<T, N> &LHS,
1338 const SmallVector<T, N> &RHS) {
1339 return LHS == RHS;
1340 }
1341};
1342
1343} // end namespace llvm
1344
1345namespace std {
1346
1347 /// Implement std::swap in terms of SmallVector swap.
1348 template<typename T>
1349 inline void
1350 swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
1351 LHS.swap(RHS);
1352 }
1353
1354 /// Implement std::swap in terms of SmallVector swap.
1355 template<typename T, unsigned N>
1356 inline void
1357 swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {
1358 LHS.swap(RHS);
1359 }
1360
1361} // end namespace std
1362
1363#endif // LLVM_ADT_SMALLVECTOR_H
1364