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// This file defines the SmallVector class.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_ADT_SMALLVECTOR_H
14#define LLVM_ADT_SMALLVECTOR_H
15
16#include "llvm/ADT/iterator_range.h"
17#include "llvm/Support/AlignOf.h"
18#include "llvm/Support/Compiler.h"
19#include "llvm/Support/MathExtras.h"
20#include "llvm/Support/MemAlloc.h"
21#include "llvm/Support/type_traits.h"
22#include "llvm/Support/ErrorHandling.h"
23#include <algorithm>
24#include <cassert>
25#include <cstddef>
26#include <cstdlib>
27#include <cstring>
28#include <initializer_list>
29#include <iterator>
30#include <memory>
31#include <new>
32#include <type_traits>
33#include <utility>
34
35namespace llvm {
36
37/// This is all the non-templated stuff common to all SmallVectors.
38class SmallVectorBase {
39protected:
40 void *BeginX;
41 unsigned Size = 0, Capacity;
42
43 SmallVectorBase() = delete;
44 SmallVectorBase(void *FirstEl, size_t Capacity)
45 : BeginX(FirstEl), Capacity(Capacity) {}
46
47 /// This is an implementation of the grow() method which only works
48 /// on POD-like data types and is out of line to reduce code duplication.
49 void grow_pod(void *FirstEl, size_t MinCapacity, size_t TSize);
50
51public:
52 size_t size() const { return Size; }
53 size_t capacity() const { return Capacity; }
54
55 LLVM_NODISCARD bool empty() const { return !Size; }
56
57 /// Set the array size to \p N, which the current array must have enough
58 /// capacity for.
59 ///
60 /// This does not construct or destroy any elements in the vector.
61 ///
62 /// Clients can use this in conjunction with capacity() to write past the end
63 /// of the buffer when they know that more elements are available, and only
64 /// update the size later. This avoids the cost of value initializing elements
65 /// which will only be overwritten.
66 void set_size(size_t Size) {
67 assert(Size <= capacity());
68 this->Size = Size;
69 }
70};
71
72/// Figure out the offset of the first element.
73template <class T, typename = void> struct SmallVectorAlignmentAndSize {
74 AlignedCharArrayUnion<SmallVectorBase> Base;
75 AlignedCharArrayUnion<T> FirstEl;
76};
77
78/// This is the part of SmallVectorTemplateBase which does not depend on whether
79/// the type T is a POD. The extra dummy template argument is used by ArrayRef
80/// to avoid unnecessarily requiring T to be complete.
81template <typename T, typename = void>
82class SmallVectorTemplateCommon : public SmallVectorBase {
83 /// Find the address of the first element. For this pointer math to be valid
84 /// with small-size of 0 for T with lots of alignment, it's important that
85 /// SmallVectorStorage is properly-aligned even for small-size of 0.
86 void *getFirstEl() const {
87 return const_cast<void *>(reinterpret_cast<const void *>(
88 reinterpret_cast<const char *>(this) +
89 offsetof(SmallVectorAlignmentAndSize<T>, FirstEl)));
90 }
91 // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
92
93protected:
94 SmallVectorTemplateCommon(size_t Size)
95 : SmallVectorBase(getFirstEl(), Size) {}
96
97 void grow_pod(size_t MinCapacity, size_t TSize) {
98 SmallVectorBase::grow_pod(getFirstEl(), MinCapacity, TSize);
99 }
100
101 /// Return true if this is a smallvector which has not had dynamic
102 /// memory allocated for it.
103 bool isSmall() const { return BeginX == getFirstEl(); }
104
105 /// Put this vector in a state of being small.
106 void resetToSmall() {
107 BeginX = getFirstEl();
108 Size = Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
109 }
110
111public:
112 using size_type = size_t;
113 using difference_type = ptrdiff_t;
114 using value_type = T;
115 using iterator = T *;
116 using const_iterator = const T *;
117
118 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
119 using reverse_iterator = std::reverse_iterator<iterator>;
120
121 using reference = T &;
122 using const_reference = const T &;
123 using pointer = T *;
124 using const_pointer = const T *;
125
126 // forward iterator creation methods.
127 iterator begin() { return (iterator)this->BeginX; }
128 const_iterator begin() const { return (const_iterator)this->BeginX; }
129 iterator end() { return begin() + size(); }
130 const_iterator end() const { return begin() + size(); }
131
132 // reverse iterator creation methods.
133 reverse_iterator rbegin() { return reverse_iterator(end()); }
134 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
135 reverse_iterator rend() { return reverse_iterator(begin()); }
136 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
137
138 size_type size_in_bytes() const { return size() * sizeof(T); }
139 size_type max_size() const { return size_type(-1) / sizeof(T); }
140
141 size_t capacity_in_bytes() const { return capacity() * sizeof(T); }
142
143 /// Return a pointer to the vector's buffer, even if empty().
144 pointer data() { return pointer(begin()); }
145 /// Return a pointer to the vector's buffer, even if empty().
146 const_pointer data() const { return const_pointer(begin()); }
147
148 reference operator[](size_type idx) {
149 assert(idx < size());
150 return begin()[idx];
151 }
152 const_reference operator[](size_type idx) const {
153 assert(idx < size());
154 return begin()[idx];
155 }
156
157 reference front() {
158 assert(!empty());
159 return begin()[0];
160 }
161 const_reference front() const {
162 assert(!empty());
163 return begin()[0];
164 }
165
166 reference back() {
167 assert(!empty());
168 return end()[-1];
169 }
170 const_reference back() const {
171 assert(!empty());
172 return end()[-1];
173 }
174};
175
176/// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put method
177/// implementations that are designed to work with non-POD-like T's.
178template <typename T, bool = is_trivially_copyable<T>::value>
179class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
180protected:
181 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
182
183 static void destroy_range(T *S, T *E) {
184 while (S != E) {
185 --E;
186 E->~T();
187 }
188 }
189
190 /// Move the range [I, E) into the uninitialized memory starting with "Dest",
191 /// constructing elements as needed.
192 template<typename It1, typename It2>
193 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
194 std::uninitialized_copy(std::make_move_iterator(I),
195 std::make_move_iterator(E), Dest);
196 }
197
198 /// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
199 /// constructing elements as needed.
200 template<typename It1, typename It2>
201 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
202 std::uninitialized_copy(I, E, Dest);
203 }
204
205 /// Grow the allocated memory (without initializing new elements), doubling
206 /// the size of the allocated memory. Guarantees space for at least one more
207 /// element, or MinSize more elements if specified.
208 void grow(size_t MinSize = 0);
209
210public:
211 void push_back(const T &Elt) {
212 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
213 this->grow();
214 ::new ((void*) this->end()) T(Elt);
215 this->set_size(this->size() + 1);
216 }
217
218 void push_back(T &&Elt) {
219 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
220 this->grow();
221 ::new ((void*) this->end()) T(::std::move(Elt));
222 this->set_size(this->size() + 1);
223 }
224
225 void pop_back() {
226 this->set_size(this->size() - 1);
227 this->end()->~T();
228 }
229};
230
231// Define this out-of-line to dissuade the C++ compiler from inlining it.
232template <typename T, bool TriviallyCopyable>
233void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) {
234 if (MinSize > UINT32_MAX)
235 report_bad_alloc_error("SmallVector capacity overflow during allocation");
236
237 // Always grow, even from zero.
238 size_t NewCapacity = size_t(NextPowerOf2(this->capacity() + 2));
239 NewCapacity = std::min(std::max(NewCapacity, MinSize), size_t(UINT32_MAX));
240 T *NewElts = static_cast<T*>(llvm::safe_malloc(NewCapacity*sizeof(T)));
241
242 // Move the elements over.
243 this->uninitialized_move(this->begin(), this->end(), NewElts);
244
245 // Destroy the original elements.
246 destroy_range(this->begin(), this->end());
247
248 // If this wasn't grown from the inline copy, deallocate the old space.
249 if (!this->isSmall())
250 free(this->begin());
251
252 this->BeginX = NewElts;
253 this->Capacity = NewCapacity;
254}
255
256/// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put
257/// method implementations that are designed to work with POD-like T's.
258template <typename T>
259class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
260protected:
261 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
262
263 // No need to do a destroy loop for POD's.
264 static void destroy_range(T *, T *) {}
265
266 /// Move the range [I, E) onto the uninitialized memory
267 /// starting with "Dest", constructing elements into it as needed.
268 template<typename It1, typename It2>
269 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
270 // Just do a copy.
271 uninitialized_copy(I, E, Dest);
272 }
273
274 /// Copy the range [I, E) onto the uninitialized memory
275 /// starting with "Dest", constructing elements into it as needed.
276 template<typename It1, typename It2>
277 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
278 // Arbitrary iterator types; just use the basic implementation.
279 std::uninitialized_copy(I, E, Dest);
280 }
281
282 /// Copy the range [I, E) onto the uninitialized memory
283 /// starting with "Dest", constructing elements into it as needed.
284 template <typename T1, typename T2>
285 static void uninitialized_copy(
286 T1 *I, T1 *E, T2 *Dest,
287 typename std::enable_if<std::is_same<typename std::remove_const<T1>::type,
288 T2>::value>::type * = nullptr) {
289 // Use memcpy for PODs iterated by pointers (which includes SmallVector
290 // iterators): std::uninitialized_copy optimizes to memmove, but we can
291 // use memcpy here. Note that I and E are iterators and thus might be
292 // invalid for memcpy if they are equal.
293 if (I != E)
294 memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T));
295 }
296
297 /// Double the size of the allocated memory, guaranteeing space for at
298 /// least one more element or MinSize if specified.
299 void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); }
300
301public:
302 void push_back(const T &Elt) {
303 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
304 this->grow();
305 memcpy(reinterpret_cast<void *>(this->end()), &Elt, sizeof(T));
306 this->set_size(this->size() + 1);
307 }
308
309 void pop_back() { this->set_size(this->size() - 1); }
310};
311
312/// This class consists of common code factored out of the SmallVector class to
313/// reduce code duplication based on the SmallVector 'N' template parameter.
314template <typename T>
315class SmallVectorImpl : public SmallVectorTemplateBase<T> {
316 using SuperClass = SmallVectorTemplateBase<T>;
317
318public:
319 using iterator = typename SuperClass::iterator;
320 using const_iterator = typename SuperClass::const_iterator;
321 using size_type = typename SuperClass::size_type;
322
323protected:
324 // Default ctor - Initialize to empty.
325 explicit SmallVectorImpl(unsigned N)
326 : SmallVectorTemplateBase<T>(N) {}
327
328public:
329 SmallVectorImpl(const SmallVectorImpl &) = delete;
330
331 ~SmallVectorImpl() {
332 // Subclass has already destructed this vector's elements.
333 // If this wasn't grown from the inline copy, deallocate the old space.
334 if (!this->isSmall())
335 free(this->begin());
336 }
337
338 void clear() {
339 this->destroy_range(this->begin(), this->end());
340 this->Size = 0;
341 }
342
343 void resize(size_type N) {
344 if (N < this->size()) {
345 this->destroy_range(this->begin()+N, this->end());
346 this->set_size(N);
347 } else if (N > this->size()) {
348 if (this->capacity() < N)
349 this->grow(N);
350 for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
351 new (&*I) T();
352 this->set_size(N);
353 }
354 }
355
356 void resize(size_type N, const T &NV) {
357 if (N < this->size()) {
358 this->destroy_range(this->begin()+N, this->end());
359 this->set_size(N);
360 } else if (N > this->size()) {
361 if (this->capacity() < N)
362 this->grow(N);
363 std::uninitialized_fill(this->end(), this->begin()+N, NV);
364 this->set_size(N);
365 }
366 }
367
368 void reserve(size_type N) {
369 if (this->capacity() < N)
370 this->grow(N);
371 }
372
373 LLVM_NODISCARD T pop_back_val() {
374 T Result = ::std::move(this->back());
375 this->pop_back();
376 return Result;
377 }
378
379 void swap(SmallVectorImpl &RHS);
380
381 /// Add the specified range to the end of the SmallVector.
382 template <typename in_iter,
383 typename = typename std::enable_if<std::is_convertible<
384 typename std::iterator_traits<in_iter>::iterator_category,
385 std::input_iterator_tag>::value>::type>
386 void append(in_iter in_start, in_iter in_end) {
387 size_type NumInputs = std::distance(in_start, in_end);
388 // Grow allocated space if needed.
389 if (NumInputs > this->capacity() - this->size())
390 this->grow(this->size()+NumInputs);
391
392 // Copy the new elements over.
393 this->uninitialized_copy(in_start, in_end, this->end());
394 this->set_size(this->size() + NumInputs);
395 }
396
397 /// Add the specified range to the end of the SmallVector.
398 void append(size_type NumInputs, const T &Elt) {
399 // Grow allocated space if needed.
400 if (NumInputs > this->capacity() - this->size())
401 this->grow(this->size()+NumInputs);
402
403 // Copy the new elements over.
404 std::uninitialized_fill_n(this->end(), NumInputs, Elt);
405 this->set_size(this->size() + NumInputs);
406 }
407
408 void append(std::initializer_list<T> IL) {
409 append(IL.begin(), IL.end());
410 }
411
412 // FIXME: Consider assigning over existing elements, rather than clearing &
413 // re-initializing them - for all assign(...) variants.
414
415 void assign(size_type NumElts, const T &Elt) {
416 clear();
417 if (this->capacity() < NumElts)
418 this->grow(NumElts);
419 this->set_size(NumElts);
420 std::uninitialized_fill(this->begin(), this->end(), Elt);
421 }
422
423 template <typename in_iter,
424 typename = typename std::enable_if<std::is_convertible<
425 typename std::iterator_traits<in_iter>::iterator_category,
426 std::input_iterator_tag>::value>::type>
427 void assign(in_iter in_start, in_iter in_end) {
428 clear();
429 append(in_start, in_end);
430 }
431
432 void assign(std::initializer_list<T> IL) {
433 clear();
434 append(IL);
435 }
436
437 iterator erase(const_iterator CI) {
438 // Just cast away constness because this is a non-const member function.
439 iterator I = const_cast<iterator>(CI);
440
441 assert(I >= this->begin() && "Iterator to erase is out of bounds.");
442 assert(I < this->end() && "Erasing at past-the-end iterator.");
443
444 iterator N = I;
445 // Shift all elts down one.
446 std::move(I+1, this->end(), I);
447 // Drop the last elt.
448 this->pop_back();
449 return(N);
450 }
451
452 iterator erase(const_iterator CS, const_iterator CE) {
453 // Just cast away constness because this is a non-const member function.
454 iterator S = const_cast<iterator>(CS);
455 iterator E = const_cast<iterator>(CE);
456
457 assert(S >= this->begin() && "Range to erase is out of bounds.");
458 assert(S <= E && "Trying to erase invalid range.");
459 assert(E <= this->end() && "Trying to erase past the end.");
460
461 iterator N = S;
462 // Shift all elts down.
463 iterator I = std::move(E, this->end(), S);
464 // Drop the last elts.
465 this->destroy_range(I, this->end());
466 this->set_size(I - this->begin());
467 return(N);
468 }
469
470 iterator insert(iterator I, T &&Elt) {
471 if (I == this->end()) { // Important special case for empty vector.
472 this->push_back(::std::move(Elt));
473 return this->end()-1;
474 }
475
476 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
477 assert(I <= this->end() && "Inserting past the end of the vector.");
478
479 if (this->size() >= this->capacity()) {
480 size_t EltNo = I-this->begin();
481 this->grow();
482 I = this->begin()+EltNo;
483 }
484
485 ::new ((void*) this->end()) T(::std::move(this->back()));
486 // Push everything else over.
487 std::move_backward(I, this->end()-1, this->end());
488 this->set_size(this->size() + 1);
489
490 // If we just moved the element we're inserting, be sure to update
491 // the reference.
492 T *EltPtr = &Elt;
493 if (I <= EltPtr && EltPtr < this->end())
494 ++EltPtr;
495
496 *I = ::std::move(*EltPtr);
497 return I;
498 }
499
500 iterator insert(iterator I, const T &Elt) {
501 if (I == this->end()) { // Important special case for empty vector.
502 this->push_back(Elt);
503 return this->end()-1;
504 }
505
506 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
507 assert(I <= this->end() && "Inserting past the end of the vector.");
508
509 if (this->size() >= this->capacity()) {
510 size_t EltNo = I-this->begin();
511 this->grow();
512 I = this->begin()+EltNo;
513 }
514 ::new ((void*) this->end()) T(std::move(this->back()));
515 // Push everything else over.
516 std::move_backward(I, this->end()-1, this->end());
517 this->set_size(this->size() + 1);
518
519 // If we just moved the element we're inserting, be sure to update
520 // the reference.
521 const T *EltPtr = &Elt;
522 if (I <= EltPtr && EltPtr < this->end())
523 ++EltPtr;
524
525 *I = *EltPtr;
526 return I;
527 }
528
529 iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
530 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
531 size_t InsertElt = I - this->begin();
532
533 if (I == this->end()) { // Important special case for empty vector.
534 append(NumToInsert, Elt);
535 return this->begin()+InsertElt;
536 }
537
538 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
539 assert(I <= this->end() && "Inserting past the end of the vector.");
540
541 // Ensure there is enough space.
542 reserve(this->size() + NumToInsert);
543
544 // Uninvalidate the iterator.
545 I = this->begin()+InsertElt;
546
547 // If there are more elements between the insertion point and the end of the
548 // range than there are being inserted, we can use a simple approach to
549 // insertion. Since we already reserved space, we know that this won't
550 // reallocate the vector.
551 if (size_t(this->end()-I) >= NumToInsert) {
552 T *OldEnd = this->end();
553 append(std::move_iterator<iterator>(this->end() - NumToInsert),
554 std::move_iterator<iterator>(this->end()));
555
556 // Copy the existing elements that get replaced.
557 std::move_backward(I, OldEnd-NumToInsert, OldEnd);
558
559 std::fill_n(I, NumToInsert, Elt);
560 return I;
561 }
562
563 // Otherwise, we're inserting more elements than exist already, and we're
564 // not inserting at the end.
565
566 // Move over the elements that we're about to overwrite.
567 T *OldEnd = this->end();
568 this->set_size(this->size() + NumToInsert);
569 size_t NumOverwritten = OldEnd-I;
570 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
571
572 // Replace the overwritten part.
573 std::fill_n(I, NumOverwritten, Elt);
574
575 // Insert the non-overwritten middle part.
576 std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
577 return I;
578 }
579
580 template <typename ItTy,
581 typename = typename std::enable_if<std::is_convertible<
582 typename std::iterator_traits<ItTy>::iterator_category,
583 std::input_iterator_tag>::value>::type>
584 iterator insert(iterator I, ItTy From, ItTy To) {
585 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
586 size_t InsertElt = I - this->begin();
587
588 if (I == this->end()) { // Important special case for empty vector.
589 append(From, To);
590 return this->begin()+InsertElt;
591 }
592
593 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
594 assert(I <= this->end() && "Inserting past the end of the vector.");
595
596 size_t NumToInsert = std::distance(From, To);
597
598 // Ensure there is enough space.
599 reserve(this->size() + NumToInsert);
600
601 // Uninvalidate the iterator.
602 I = this->begin()+InsertElt;
603
604 // If there are more elements between the insertion point and the end of the
605 // range than there are being inserted, we can use a simple approach to
606 // insertion. Since we already reserved space, we know that this won't
607 // reallocate the vector.
608 if (size_t(this->end()-I) >= NumToInsert) {
609 T *OldEnd = this->end();
610 append(std::move_iterator<iterator>(this->end() - NumToInsert),
611 std::move_iterator<iterator>(this->end()));
612
613 // Copy the existing elements that get replaced.
614 std::move_backward(I, OldEnd-NumToInsert, OldEnd);
615
616 std::copy(From, To, I);
617 return I;
618 }
619
620 // Otherwise, we're inserting more elements than exist already, and we're
621 // not inserting at the end.
622
623 // Move over the elements that we're about to overwrite.
624 T *OldEnd = this->end();
625 this->set_size(this->size() + NumToInsert);
626 size_t NumOverwritten = OldEnd-I;
627 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
628
629 // Replace the overwritten part.
630 for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
631 *J = *From;
632 ++J; ++From;
633 }
634
635 // Insert the non-overwritten middle part.
636 this->uninitialized_copy(From, To, OldEnd);
637 return I;
638 }
639
640 void insert(iterator I, std::initializer_list<T> IL) {
641 insert(I, IL.begin(), IL.end());
642 }
643
644 template <typename... ArgTypes> void emplace_back(ArgTypes &&... Args) {
645 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
646 this->grow();
647 ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
648 this->set_size(this->size() + 1);
649 }
650
651 SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
652
653 SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
654
655 bool operator==(const SmallVectorImpl &RHS) const {
656 if (this->size() != RHS.size()) return false;
657 return std::equal(this->begin(), this->end(), RHS.begin());
658 }
659 bool operator!=(const SmallVectorImpl &RHS) const {
660 return !(*this == RHS);
661 }
662
663 bool operator<(const SmallVectorImpl &RHS) const {
664 return std::lexicographical_compare(this->begin(), this->end(),
665 RHS.begin(), RHS.end());
666 }
667};
668
669template <typename T>
670void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
671 if (this == &RHS) return;
672
673 // We can only avoid copying elements if neither vector is small.
674 if (!this->isSmall() && !RHS.isSmall()) {
675 std::swap(this->BeginX, RHS.BeginX);
676 std::swap(this->Size, RHS.Size);
677 std::swap(this->Capacity, RHS.Capacity);
678 return;
679 }
680 if (RHS.size() > this->capacity())
681 this->grow(RHS.size());
682 if (this->size() > RHS.capacity())
683 RHS.grow(this->size());
684
685 // Swap the shared elements.
686 size_t NumShared = this->size();
687 if (NumShared > RHS.size()) NumShared = RHS.size();
688 for (size_type i = 0; i != NumShared; ++i)
689 std::swap((*this)[i], RHS[i]);
690
691 // Copy over the extra elts.
692 if (this->size() > RHS.size()) {
693 size_t EltDiff = this->size() - RHS.size();
694 this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
695 RHS.set_size(RHS.size() + EltDiff);
696 this->destroy_range(this->begin()+NumShared, this->end());
697 this->set_size(NumShared);
698 } else if (RHS.size() > this->size()) {
699 size_t EltDiff = RHS.size() - this->size();
700 this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
701 this->set_size(this->size() + EltDiff);
702 this->destroy_range(RHS.begin()+NumShared, RHS.end());
703 RHS.set_size(NumShared);
704 }
705}
706
707template <typename T>
708SmallVectorImpl<T> &SmallVectorImpl<T>::
709 operator=(const SmallVectorImpl<T> &RHS) {
710 // Avoid self-assignment.
711 if (this == &RHS) return *this;
712
713 // If we already have sufficient space, assign the common elements, then
714 // destroy any excess.
715 size_t RHSSize = RHS.size();
716 size_t CurSize = this->size();
717 if (CurSize >= RHSSize) {
718 // Assign common elements.
719 iterator NewEnd;
720 if (RHSSize)
721 NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
722 else
723 NewEnd = this->begin();
724
725 // Destroy excess elements.
726 this->destroy_range(NewEnd, this->end());
727
728 // Trim.
729 this->set_size(RHSSize);
730 return *this;
731 }
732
733 // If we have to grow to have enough elements, destroy the current elements.
734 // This allows us to avoid copying them during the grow.
735 // FIXME: don't do this if they're efficiently moveable.
736 if (this->capacity() < RHSSize) {
737 // Destroy current elements.
738 this->destroy_range(this->begin(), this->end());
739 this->set_size(0);
740 CurSize = 0;
741 this->grow(RHSSize);
742 } else if (CurSize) {
743 // Otherwise, use assignment for the already-constructed elements.
744 std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
745 }
746
747 // Copy construct the new elements in place.
748 this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
749 this->begin()+CurSize);
750
751 // Set end.
752 this->set_size(RHSSize);
753 return *this;
754}
755
756template <typename T>
757SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
758 // Avoid self-assignment.
759 if (this == &RHS) return *this;
760
761 // If the RHS isn't small, clear this vector and then steal its buffer.
762 if (!RHS.isSmall()) {
763 this->destroy_range(this->begin(), this->end());
764 if (!this->isSmall()) free(this->begin());
765 this->BeginX = RHS.BeginX;
766 this->Size = RHS.Size;
767 this->Capacity = RHS.Capacity;
768 RHS.resetToSmall();
769 return *this;
770 }
771
772 // If we already have sufficient space, assign the common elements, then
773 // destroy any excess.
774 size_t RHSSize = RHS.size();
775 size_t CurSize = this->size();
776 if (CurSize >= RHSSize) {
777 // Assign common elements.
778 iterator NewEnd = this->begin();
779 if (RHSSize)
780 NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd);
781
782 // Destroy excess elements and trim the bounds.
783 this->destroy_range(NewEnd, this->end());
784 this->set_size(RHSSize);
785
786 // Clear the RHS.
787 RHS.clear();
788
789 return *this;
790 }
791
792 // If we have to grow to have enough elements, destroy the current elements.
793 // This allows us to avoid copying them during the grow.
794 // FIXME: this may not actually make any sense if we can efficiently move
795 // elements.
796 if (this->capacity() < RHSSize) {
797 // Destroy current elements.
798 this->destroy_range(this->begin(), this->end());
799 this->set_size(0);
800 CurSize = 0;
801 this->grow(RHSSize);
802 } else if (CurSize) {
803 // Otherwise, use assignment for the already-constructed elements.
804 std::move(RHS.begin(), RHS.begin()+CurSize, this->begin());
805 }
806
807 // Move-construct the new elements in place.
808 this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
809 this->begin()+CurSize);
810
811 // Set end.
812 this->set_size(RHSSize);
813
814 RHS.clear();
815 return *this;
816}
817
818/// Storage for the SmallVector elements. This is specialized for the N=0 case
819/// to avoid allocating unnecessary storage.
820template <typename T, unsigned N>
821struct SmallVectorStorage {
822 AlignedCharArrayUnion<T> InlineElts[N];
823};
824
825/// We need the storage to be properly aligned even for small-size of 0 so that
826/// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is
827/// well-defined.
828template <typename T> struct alignas(alignof(T)) SmallVectorStorage<T, 0> {};
829
830/// This is a 'vector' (really, a variable-sized array), optimized
831/// for the case when the array is small. It contains some number of elements
832/// in-place, which allows it to avoid heap allocation when the actual number of
833/// elements is below that threshold. This allows normal "small" cases to be
834/// fast without losing generality for large inputs.
835///
836/// Note that this does not attempt to be exception safe.
837///
838template <typename T, unsigned N>
839class SmallVector : public SmallVectorImpl<T>, SmallVectorStorage<T, N> {
840public:
841 SmallVector() : SmallVectorImpl<T>(N) {}
842
843 ~SmallVector() {
844 // Destroy the constructed elements in the vector.
845 this->destroy_range(this->begin(), this->end());
846 }
847
848 explicit SmallVector(size_t Size, const T &Value = T())
849 : SmallVectorImpl<T>(N) {
850 this->assign(Size, Value);
851 }
852
853 template <typename ItTy,
854 typename = typename std::enable_if<std::is_convertible<
855 typename std::iterator_traits<ItTy>::iterator_category,
856 std::input_iterator_tag>::value>::type>
857 SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
858 this->append(S, E);
859 }
860
861 template <typename RangeTy>
862 explicit SmallVector(const iterator_range<RangeTy> &R)
863 : SmallVectorImpl<T>(N) {
864 this->append(R.begin(), R.end());
865 }
866
867 SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) {
868 this->assign(IL);
869 }
870
871 SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
872 if (!RHS.empty())
873 SmallVectorImpl<T>::operator=(RHS);
874 }
875
876 const SmallVector &operator=(const SmallVector &RHS) {
877 SmallVectorImpl<T>::operator=(RHS);
878 return *this;
879 }
880
881 SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
882 if (!RHS.empty())
883 SmallVectorImpl<T>::operator=(::std::move(RHS));
884 }
885
886 SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
887 if (!RHS.empty())
888 SmallVectorImpl<T>::operator=(::std::move(RHS));
889 }
890
891 const SmallVector &operator=(SmallVector &&RHS) {
892 SmallVectorImpl<T>::operator=(::std::move(RHS));
893 return *this;
894 }
895
896 const SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
897 SmallVectorImpl<T>::operator=(::std::move(RHS));
898 return *this;
899 }
900
901 const SmallVector &operator=(std::initializer_list<T> IL) {
902 this->assign(IL);
903 return *this;
904 }
905};
906
907template <typename T, unsigned N>
908inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
909 return X.capacity_in_bytes();
910}
911
912} // end namespace llvm
913
914namespace std {
915
916 /// Implement std::swap in terms of SmallVector swap.
917 template<typename T>
918 inline void
919 swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
920 LHS.swap(RHS);
921 }
922
923 /// Implement std::swap in terms of SmallVector swap.
924 template<typename T, unsigned N>
925 inline void
926 swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {
927 LHS.swap(RHS);
928 }
929
930} // end namespace std
931
932#endif // LLVM_ADT_SMALLVECTOR_H
933