1//===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
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/iterator_range.h"
18#include "llvm/Support/AlignOf.h"
19#include "llvm/Support/Compiler.h"
20#include "llvm/Support/MathExtras.h"
21#include "llvm/Support/MemAlloc.h"
22#include "llvm/Support/type_traits.h"
23#include "llvm/Support/ErrorHandling.h"
24#include <algorithm>
25#include <cassert>
26#include <cstddef>
27#include <cstdlib>
28#include <cstring>
29#include <initializer_list>
30#include <iterator>
31#include <memory>
32#include <new>
33#include <type_traits>
34#include <utility>
35
36namespace llvm {
37
38/// This is all the non-templated stuff common to all SmallVectors.
39class SmallVectorBase {
40protected:
41 void *BeginX;
42 unsigned Size = 0, Capacity;
43
44 SmallVectorBase() = delete;
45 SmallVectorBase(void *FirstEl, size_t Capacity)
46 : BeginX(FirstEl), Capacity(Capacity) {}
47
48 /// This is an implementation of the grow() method which only works
49 /// on POD-like data types and is out of line to reduce code duplication.
50 void grow_pod(void *FirstEl, size_t MinCapacity, size_t TSize);
51
52public:
53 size_t size() const { return Size; }
54 size_t capacity() const { return Capacity; }
55
56 LLVM_NODISCARD bool empty() const { return !Size; }
57
58 /// Set the array size to \p N, which the current array must have enough
59 /// capacity for.
60 ///
61 /// This does not construct or destroy any elements in the vector.
62 ///
63 /// Clients can use this in conjunction with capacity() to write past the end
64 /// of the buffer when they know that more elements are available, and only
65 /// update the size later. This avoids the cost of value initializing elements
66 /// which will only be overwritten.
67 void set_size(size_t Size) {
68 assert(Size <= capacity());
69 this->Size = Size;
70 }
71};
72
73/// Figure out the offset of the first element.
74template <class T, typename = void> struct SmallVectorAlignmentAndSize {
75 AlignedCharArrayUnion<SmallVectorBase> Base;
76 AlignedCharArrayUnion<T> FirstEl;
77};
78
79/// This is the part of SmallVectorTemplateBase which does not depend on whether
80/// the type T is a POD. The extra dummy template argument is used by ArrayRef
81/// to avoid unnecessarily requiring T to be complete.
82template <typename T, typename = void>
83class SmallVectorTemplateCommon : public SmallVectorBase {
84 /// Find the address of the first element. For this pointer math to be valid
85 /// with small-size of 0 for T with lots of alignment, it's important that
86 /// SmallVectorStorage is properly-aligned even for small-size of 0.
87 void *getFirstEl() const {
88 return const_cast<void *>(reinterpret_cast<const void *>(
89 reinterpret_cast<const char *>(this) +
90 offsetof(SmallVectorAlignmentAndSize<T>, FirstEl)));
91 }
92 // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
93
94protected:
95 SmallVectorTemplateCommon(size_t Size)
96 : SmallVectorBase(getFirstEl(), Size) {}
97
98 void grow_pod(size_t MinCapacity, size_t TSize) {
99 SmallVectorBase::grow_pod(getFirstEl(), MinCapacity, TSize);
100 }
101
102 /// Return true if this is a smallvector which has not had dynamic
103 /// memory allocated for it.
104 bool isSmall() const { return BeginX == getFirstEl(); }
105
106 /// Put this vector in a state of being small.
107 void resetToSmall() {
108 BeginX = getFirstEl();
109 Size = Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
110 }
111
112public:
113 using size_type = size_t;
114 using difference_type = ptrdiff_t;
115 using value_type = T;
116 using iterator = T *;
117 using const_iterator = const T *;
118
119 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
120 using reverse_iterator = std::reverse_iterator<iterator>;
121
122 using reference = T &;
123 using const_reference = const T &;
124 using pointer = T *;
125 using const_pointer = const T *;
126
127 // forward iterator creation methods.
128 LLVM_ATTRIBUTE_ALWAYS_INLINE
129 iterator begin() { return (iterator)this->BeginX; }
130 LLVM_ATTRIBUTE_ALWAYS_INLINE
131 const_iterator begin() const { return (const_iterator)this->BeginX; }
132 LLVM_ATTRIBUTE_ALWAYS_INLINE
133 iterator end() { return begin() + size(); }
134 LLVM_ATTRIBUTE_ALWAYS_INLINE
135 const_iterator end() const { return begin() + size(); }
136
137 // reverse iterator creation methods.
138 reverse_iterator rbegin() { return reverse_iterator(end()); }
139 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
140 reverse_iterator rend() { return reverse_iterator(begin()); }
141 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
142
143 size_type size_in_bytes() const { return size() * sizeof(T); }
144 size_type max_size() const { return size_type(-1) / sizeof(T); }
145
146 size_t capacity_in_bytes() const { return capacity() * sizeof(T); }
147
148 /// Return a pointer to the vector's buffer, even if empty().
149 pointer data() { return pointer(begin()); }
150 /// Return a pointer to the vector's buffer, even if empty().
151 const_pointer data() const { return const_pointer(begin()); }
152
153 LLVM_ATTRIBUTE_ALWAYS_INLINE
154 reference operator[](size_type idx) {
155 assert(idx < size());
156 return begin()[idx];
157 }
158 LLVM_ATTRIBUTE_ALWAYS_INLINE
159 const_reference operator[](size_type idx) const {
160 assert(idx < size());
161 return begin()[idx];
162 }
163
164 reference front() {
165 assert(!empty());
166 return begin()[0];
167 }
168 const_reference front() const {
169 assert(!empty());
170 return begin()[0];
171 }
172
173 reference back() {
174 assert(!empty());
175 return end()[-1];
176 }
177 const_reference back() const {
178 assert(!empty());
179 return end()[-1];
180 }
181};
182
183/// SmallVectorTemplateBase<isPodLike = false> - This is where we put method
184/// implementations that are designed to work with non-POD-like T's.
185template <typename T, bool isPodLike>
186class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
187protected:
188 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
189
190 static void destroy_range(T *S, T *E) {
191 while (S != E) {
192 --E;
193 E->~T();
194 }
195 }
196
197 /// Move the range [I, E) into the uninitialized memory starting with "Dest",
198 /// constructing elements as needed.
199 template<typename It1, typename It2>
200 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
201 std::uninitialized_copy(std::make_move_iterator(I),
202 std::make_move_iterator(E), Dest);
203 }
204
205 /// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
206 /// constructing elements as needed.
207 template<typename It1, typename It2>
208 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
209 std::uninitialized_copy(I, E, Dest);
210 }
211
212 /// Grow the allocated memory (without initializing new elements), doubling
213 /// the size of the allocated memory. Guarantees space for at least one more
214 /// element, or MinSize more elements if specified.
215 void grow(size_t MinSize = 0);
216
217public:
218 void push_back(const T &Elt) {
219 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
220 this->grow();
221 ::new ((void*) this->end()) T(Elt);
222 this->set_size(this->size() + 1);
223 }
224
225 void push_back(T &&Elt) {
226 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
227 this->grow();
228 ::new ((void*) this->end()) T(::std::move(Elt));
229 this->set_size(this->size() + 1);
230 }
231
232 void pop_back() {
233 this->set_size(this->size() - 1);
234 this->end()->~T();
235 }
236};
237
238// Define this out-of-line to dissuade the C++ compiler from inlining it.
239template <typename T, bool isPodLike>
240void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) {
241 if (MinSize > UINT32_MAX)
242 report_bad_alloc_error("SmallVector capacity overflow during allocation");
243
244 // Always grow, even from zero.
245 size_t NewCapacity = size_t(NextPowerOf2(this->capacity() + 2));
246 NewCapacity = std::min(std::max(NewCapacity, MinSize), size_t(UINT32_MAX));
247 T *NewElts = static_cast<T*>(llvm::safe_malloc(NewCapacity*sizeof(T)));
248
249 // Move the elements over.
250 this->uninitialized_move(this->begin(), this->end(), NewElts);
251
252 // Destroy the original elements.
253 destroy_range(this->begin(), this->end());
254
255 // If this wasn't grown from the inline copy, deallocate the old space.
256 if (!this->isSmall())
257 free(this->begin());
258
259 this->BeginX = NewElts;
260 this->Capacity = NewCapacity;
261}
262
263
264/// SmallVectorTemplateBase<isPodLike = true> - This is where we put method
265/// implementations that are designed to work with POD-like T's.
266template <typename T>
267class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
268protected:
269 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
270
271 // No need to do a destroy loop for POD's.
272 static void destroy_range(T *, T *) {}
273
274 /// Move 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_move(It1 I, It1 E, It2 Dest) {
278 // Just do a copy.
279 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 It1, typename It2>
285 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
286 // Arbitrary iterator types; just use the basic implementation.
287 std::uninitialized_copy(I, E, Dest);
288 }
289
290 /// Copy the range [I, E) onto the uninitialized memory
291 /// starting with "Dest", constructing elements into it as needed.
292 template <typename T1, typename T2>
293 static void uninitialized_copy(
294 T1 *I, T1 *E, T2 *Dest,
295 typename std::enable_if<std::is_same<typename std::remove_const<T1>::type,
296 T2>::value>::type * = nullptr) {
297 // Use memcpy for PODs iterated by pointers (which includes SmallVector
298 // iterators): std::uninitialized_copy optimizes to memmove, but we can
299 // use memcpy here. Note that I and E are iterators and thus might be
300 // invalid for memcpy if they are equal.
301 if (I != E)
302 memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T));
303 }
304
305 /// Double the size of the allocated memory, guaranteeing space for at
306 /// least one more element or MinSize if specified.
307 void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); }
308
309public:
310 void push_back(const T &Elt) {
311 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
312 this->grow();
313 memcpy(reinterpret_cast<void *>(this->end()), &Elt, sizeof(T));
314 this->set_size(this->size() + 1);
315 }
316
317 void pop_back() { this->set_size(this->size() - 1); }
318};
319
320/// This class consists of common code factored out of the SmallVector class to
321/// reduce code duplication based on the SmallVector 'N' template parameter.
322template <typename T>
323class SmallVectorImpl : public SmallVectorTemplateBase<T, isPodLike<T>::value> {
324 using SuperClass = SmallVectorTemplateBase<T, isPodLike<T>::value>;
325
326public:
327 using iterator = typename SuperClass::iterator;
328 using const_iterator = typename SuperClass::const_iterator;
329 using size_type = typename SuperClass::size_type;
330
331protected:
332 // Default ctor - Initialize to empty.
333 explicit SmallVectorImpl(unsigned N)
334 : SmallVectorTemplateBase<T, isPodLike<T>::value>(N) {}
335
336public:
337 SmallVectorImpl(const SmallVectorImpl &) = delete;
338
339 ~SmallVectorImpl() {
340 // Subclass has already destructed this vector's elements.
341 // If this wasn't grown from the inline copy, deallocate the old space.
342 if (!this->isSmall())
343 free(this->begin());
344 }
345
346 void clear() {
347 this->destroy_range(this->begin(), this->end());
348 this->Size = 0;
349 }
350
351 void resize(size_type N) {
352 if (N < this->size()) {
353 this->destroy_range(this->begin()+N, this->end());
354 this->set_size(N);
355 } else if (N > this->size()) {
356 if (this->capacity() < N)
357 this->grow(N);
358 for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
359 new (&*I) T();
360 this->set_size(N);
361 }
362 }
363
364 void resize(size_type N, const T &NV) {
365 if (N < this->size()) {
366 this->destroy_range(this->begin()+N, this->end());
367 this->set_size(N);
368 } else if (N > this->size()) {
369 if (this->capacity() < N)
370 this->grow(N);
371 std::uninitialized_fill(this->end(), this->begin()+N, NV);
372 this->set_size(N);
373 }
374 }
375
376 void reserve(size_type N) {
377 if (this->capacity() < N)
378 this->grow(N);
379 }
380
381 LLVM_NODISCARD T pop_back_val() {
382 T Result = ::std::move(this->back());
383 this->pop_back();
384 return Result;
385 }
386
387 void swap(SmallVectorImpl &RHS);
388
389 /// Add the specified range to the end of the SmallVector.
390 template <typename in_iter,
391 typename = typename std::enable_if<std::is_convertible<
392 typename std::iterator_traits<in_iter>::iterator_category,
393 std::input_iterator_tag>::value>::type>
394 void append(in_iter in_start, in_iter in_end) {
395 size_type NumInputs = std::distance(in_start, in_end);
396 // Grow allocated space if needed.
397 if (NumInputs > this->capacity() - this->size())
398 this->grow(this->size()+NumInputs);
399
400 // Copy the new elements over.
401 this->uninitialized_copy(in_start, in_end, this->end());
402 this->set_size(this->size() + NumInputs);
403 }
404
405 /// Add the specified range to the end of the SmallVector.
406 void append(size_type NumInputs, const T &Elt) {
407 // Grow allocated space if needed.
408 if (NumInputs > this->capacity() - this->size())
409 this->grow(this->size()+NumInputs);
410
411 // Copy the new elements over.
412 std::uninitialized_fill_n(this->end(), NumInputs, Elt);
413 this->set_size(this->size() + NumInputs);
414 }
415
416 void append(std::initializer_list<T> IL) {
417 append(IL.begin(), IL.end());
418 }
419
420 // FIXME: Consider assigning over existing elements, rather than clearing &
421 // re-initializing them - for all assign(...) variants.
422
423 void assign(size_type NumElts, const T &Elt) {
424 clear();
425 if (this->capacity() < NumElts)
426 this->grow(NumElts);
427 this->set_size(NumElts);
428 std::uninitialized_fill(this->begin(), this->end(), Elt);
429 }
430
431 template <typename in_iter,
432 typename = typename std::enable_if<std::is_convertible<
433 typename std::iterator_traits<in_iter>::iterator_category,
434 std::input_iterator_tag>::value>::type>
435 void assign(in_iter in_start, in_iter in_end) {
436 clear();
437 append(in_start, in_end);
438 }
439
440 void assign(std::initializer_list<T> IL) {
441 clear();
442 append(IL);
443 }
444
445 iterator erase(const_iterator CI) {
446 // Just cast away constness because this is a non-const member function.
447 iterator I = const_cast<iterator>(CI);
448
449 assert(I >= this->begin() && "Iterator to erase is out of bounds.");
450 assert(I < this->end() && "Erasing at past-the-end iterator.");
451
452 iterator N = I;
453 // Shift all elts down one.
454 std::move(I+1, this->end(), I);
455 // Drop the last elt.
456 this->pop_back();
457 return(N);
458 }
459
460 iterator erase(const_iterator CS, const_iterator CE) {
461 // Just cast away constness because this is a non-const member function.
462 iterator S = const_cast<iterator>(CS);
463 iterator E = const_cast<iterator>(CE);
464
465 assert(S >= this->begin() && "Range to erase is out of bounds.");
466 assert(S <= E && "Trying to erase invalid range.");
467 assert(E <= this->end() && "Trying to erase past the end.");
468
469 iterator N = S;
470 // Shift all elts down.
471 iterator I = std::move(E, this->end(), S);
472 // Drop the last elts.
473 this->destroy_range(I, this->end());
474 this->set_size(I - this->begin());
475 return(N);
476 }
477
478 iterator insert(iterator I, T &&Elt) {
479 if (I == this->end()) { // Important special case for empty vector.
480 this->push_back(::std::move(Elt));
481 return this->end()-1;
482 }
483
484 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
485 assert(I <= this->end() && "Inserting past the end of the vector.");
486
487 if (this->size() >= this->capacity()) {
488 size_t EltNo = I-this->begin();
489 this->grow();
490 I = this->begin()+EltNo;
491 }
492
493 ::new ((void*) this->end()) T(::std::move(this->back()));
494 // Push everything else over.
495 std::move_backward(I, this->end()-1, this->end());
496 this->set_size(this->size() + 1);
497
498 // If we just moved the element we're inserting, be sure to update
499 // the reference.
500 T *EltPtr = &Elt;
501 if (I <= EltPtr && EltPtr < this->end())
502 ++EltPtr;
503
504 *I = ::std::move(*EltPtr);
505 return I;
506 }
507
508 iterator insert(iterator I, const T &Elt) {
509 if (I == this->end()) { // Important special case for empty vector.
510 this->push_back(Elt);
511 return this->end()-1;
512 }
513
514 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
515 assert(I <= this->end() && "Inserting past the end of the vector.");
516
517 if (this->size() >= this->capacity()) {
518 size_t EltNo = I-this->begin();
519 this->grow();
520 I = this->begin()+EltNo;
521 }
522 ::new ((void*) this->end()) T(std::move(this->back()));
523 // Push everything else over.
524 std::move_backward(I, this->end()-1, this->end());
525 this->set_size(this->size() + 1);
526
527 // If we just moved the element we're inserting, be sure to update
528 // the reference.
529 const T *EltPtr = &Elt;
530 if (I <= EltPtr && EltPtr < this->end())
531 ++EltPtr;
532
533 *I = *EltPtr;
534 return I;
535 }
536
537 iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
538 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
539 size_t InsertElt = I - this->begin();
540
541 if (I == this->end()) { // Important special case for empty vector.
542 append(NumToInsert, Elt);
543 return this->begin()+InsertElt;
544 }
545
546 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
547 assert(I <= this->end() && "Inserting past the end of the vector.");
548
549 // Ensure there is enough space.
550 reserve(this->size() + NumToInsert);
551
552 // Uninvalidate the iterator.
553 I = this->begin()+InsertElt;
554
555 // If there are more elements between the insertion point and the end of the
556 // range than there are being inserted, we can use a simple approach to
557 // insertion. Since we already reserved space, we know that this won't
558 // reallocate the vector.
559 if (size_t(this->end()-I) >= NumToInsert) {
560 T *OldEnd = this->end();
561 append(std::move_iterator<iterator>(this->end() - NumToInsert),
562 std::move_iterator<iterator>(this->end()));
563
564 // Copy the existing elements that get replaced.
565 std::move_backward(I, OldEnd-NumToInsert, OldEnd);
566
567 std::fill_n(I, NumToInsert, Elt);
568 return I;
569 }
570
571 // Otherwise, we're inserting more elements than exist already, and we're
572 // not inserting at the end.
573
574 // Move over the elements that we're about to overwrite.
575 T *OldEnd = this->end();
576 this->set_size(this->size() + NumToInsert);
577 size_t NumOverwritten = OldEnd-I;
578 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
579
580 // Replace the overwritten part.
581 std::fill_n(I, NumOverwritten, Elt);
582
583 // Insert the non-overwritten middle part.
584 std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
585 return I;
586 }
587
588 template <typename ItTy,
589 typename = typename std::enable_if<std::is_convertible<
590 typename std::iterator_traits<ItTy>::iterator_category,
591 std::input_iterator_tag>::value>::type>
592 iterator insert(iterator I, ItTy From, ItTy To) {
593 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
594 size_t InsertElt = I - this->begin();
595
596 if (I == this->end()) { // Important special case for empty vector.
597 append(From, To);
598 return this->begin()+InsertElt;
599 }
600
601 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
602 assert(I <= this->end() && "Inserting past the end of the vector.");
603
604 size_t NumToInsert = std::distance(From, To);
605
606 // Ensure there is enough space.
607 reserve(this->size() + NumToInsert);
608
609 // Uninvalidate the iterator.
610 I = this->begin()+InsertElt;
611
612 // If there are more elements between the insertion point and the end of the
613 // range than there are being inserted, we can use a simple approach to
614 // insertion. Since we already reserved space, we know that this won't
615 // reallocate the vector.
616 if (size_t(this->end()-I) >= NumToInsert) {
617 T *OldEnd = this->end();
618 append(std::move_iterator<iterator>(this->end() - NumToInsert),
619 std::move_iterator<iterator>(this->end()));
620
621 // Copy the existing elements that get replaced.
622 std::move_backward(I, OldEnd-NumToInsert, OldEnd);
623
624 std::copy(From, To, I);
625 return I;
626 }
627
628 // Otherwise, we're inserting more elements than exist already, and we're
629 // not inserting at the end.
630
631 // Move over the elements that we're about to overwrite.
632 T *OldEnd = this->end();
633 this->set_size(this->size() + NumToInsert);
634 size_t NumOverwritten = OldEnd-I;
635 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
636
637 // Replace the overwritten part.
638 for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
639 *J = *From;
640 ++J; ++From;
641 }
642
643 // Insert the non-overwritten middle part.
644 this->uninitialized_copy(From, To, OldEnd);
645 return I;
646 }
647
648 void insert(iterator I, std::initializer_list<T> IL) {
649 insert(I, IL.begin(), IL.end());
650 }
651
652 template <typename... ArgTypes> void emplace_back(ArgTypes &&... Args) {
653 if (LLVM_UNLIKELY(this->size() >= this->capacity()))
654 this->grow();
655 ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
656 this->set_size(this->size() + 1);
657 }
658
659 SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
660
661 SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
662
663 bool operator==(const SmallVectorImpl &RHS) const {
664 if (this->size() != RHS.size()) return false;
665 return std::equal(this->begin(), this->end(), RHS.begin());
666 }
667 bool operator!=(const SmallVectorImpl &RHS) const {
668 return !(*this == RHS);
669 }
670
671 bool operator<(const SmallVectorImpl &RHS) const {
672 return std::lexicographical_compare(this->begin(), this->end(),
673 RHS.begin(), RHS.end());
674 }
675};
676
677template <typename T>
678void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
679 if (this == &RHS) return;
680
681 // We can only avoid copying elements if neither vector is small.
682 if (!this->isSmall() && !RHS.isSmall()) {
683 std::swap(this->BeginX, RHS.BeginX);
684 std::swap(this->Size, RHS.Size);
685 std::swap(this->Capacity, RHS.Capacity);
686 return;
687 }
688 if (RHS.size() > this->capacity())
689 this->grow(RHS.size());
690 if (this->size() > RHS.capacity())
691 RHS.grow(this->size());
692
693 // Swap the shared elements.
694 size_t NumShared = this->size();
695 if (NumShared > RHS.size()) NumShared = RHS.size();
696 for (size_type i = 0; i != NumShared; ++i)
697 std::swap((*this)[i], RHS[i]);
698
699 // Copy over the extra elts.
700 if (this->size() > RHS.size()) {
701 size_t EltDiff = this->size() - RHS.size();
702 this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
703 RHS.set_size(RHS.size() + EltDiff);
704 this->destroy_range(this->begin()+NumShared, this->end());
705 this->set_size(NumShared);
706 } else if (RHS.size() > this->size()) {
707 size_t EltDiff = RHS.size() - this->size();
708 this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
709 this->set_size(this->size() + EltDiff);
710 this->destroy_range(RHS.begin()+NumShared, RHS.end());
711 RHS.set_size(NumShared);
712 }
713}
714
715template <typename T>
716SmallVectorImpl<T> &SmallVectorImpl<T>::
717 operator=(const SmallVectorImpl<T> &RHS) {
718 // Avoid self-assignment.
719 if (this == &RHS) return *this;
720
721 // If we already have sufficient space, assign the common elements, then
722 // destroy any excess.
723 size_t RHSSize = RHS.size();
724 size_t CurSize = this->size();
725 if (CurSize >= RHSSize) {
726 // Assign common elements.
727 iterator NewEnd;
728 if (RHSSize)
729 NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
730 else
731 NewEnd = this->begin();
732
733 // Destroy excess elements.
734 this->destroy_range(NewEnd, this->end());
735
736 // Trim.
737 this->set_size(RHSSize);
738 return *this;
739 }
740
741 // If we have to grow to have enough elements, destroy the current elements.
742 // This allows us to avoid copying them during the grow.
743 // FIXME: don't do this if they're efficiently moveable.
744 if (this->capacity() < RHSSize) {
745 // Destroy current elements.
746 this->destroy_range(this->begin(), this->end());
747 this->set_size(0);
748 CurSize = 0;
749 this->grow(RHSSize);
750 } else if (CurSize) {
751 // Otherwise, use assignment for the already-constructed elements.
752 std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
753 }
754
755 // Copy construct the new elements in place.
756 this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
757 this->begin()+CurSize);
758
759 // Set end.
760 this->set_size(RHSSize);
761 return *this;
762}
763
764template <typename T>
765SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
766 // Avoid self-assignment.
767 if (this == &RHS) return *this;
768
769 // If the RHS isn't small, clear this vector and then steal its buffer.
770 if (!RHS.isSmall()) {
771 this->destroy_range(this->begin(), this->end());
772 if (!this->isSmall()) free(this->begin());
773 this->BeginX = RHS.BeginX;
774 this->Size = RHS.Size;
775 this->Capacity = RHS.Capacity;
776 RHS.resetToSmall();
777 return *this;
778 }
779
780 // If we already have sufficient space, assign the common elements, then
781 // destroy any excess.
782 size_t RHSSize = RHS.size();
783 size_t CurSize = this->size();
784 if (CurSize >= RHSSize) {
785 // Assign common elements.
786 iterator NewEnd = this->begin();
787 if (RHSSize)
788 NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd);
789
790 // Destroy excess elements and trim the bounds.
791 this->destroy_range(NewEnd, this->end());
792 this->set_size(RHSSize);
793
794 // Clear the RHS.
795 RHS.clear();
796
797 return *this;
798 }
799
800 // If we have to grow to have enough elements, destroy the current elements.
801 // This allows us to avoid copying them during the grow.
802 // FIXME: this may not actually make any sense if we can efficiently move
803 // elements.
804 if (this->capacity() < RHSSize) {
805 // Destroy current elements.
806 this->destroy_range(this->begin(), this->end());
807 this->set_size(0);
808 CurSize = 0;
809 this->grow(RHSSize);
810 } else if (CurSize) {
811 // Otherwise, use assignment for the already-constructed elements.
812 std::move(RHS.begin(), RHS.begin()+CurSize, this->begin());
813 }
814
815 // Move-construct the new elements in place.
816 this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
817 this->begin()+CurSize);
818
819 // Set end.
820 this->set_size(RHSSize);
821
822 RHS.clear();
823 return *this;
824}
825
826/// Storage for the SmallVector elements. This is specialized for the N=0 case
827/// to avoid allocating unnecessary storage.
828template <typename T, unsigned N>
829struct SmallVectorStorage {
830 AlignedCharArrayUnion<T> InlineElts[N];
831};
832
833/// We need the storage to be properly aligned even for small-size of 0 so that
834/// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is
835/// well-defined.
836template <typename T> struct alignas(alignof(T)) SmallVectorStorage<T, 0> {};
837
838/// This is a 'vector' (really, a variable-sized array), optimized
839/// for the case when the array is small. It contains some number of elements
840/// in-place, which allows it to avoid heap allocation when the actual number of
841/// elements is below that threshold. This allows normal "small" cases to be
842/// fast without losing generality for large inputs.
843///
844/// Note that this does not attempt to be exception safe.
845///
846template <typename T, unsigned N>
847class SmallVector : public SmallVectorImpl<T>, SmallVectorStorage<T, N> {
848public:
849 SmallVector() : SmallVectorImpl<T>(N) {}
850
851 ~SmallVector() {
852 // Destroy the constructed elements in the vector.
853 this->destroy_range(this->begin(), this->end());
854 }
855
856 explicit SmallVector(size_t Size, const T &Value = T())
857 : SmallVectorImpl<T>(N) {
858 this->assign(Size, Value);
859 }
860
861 template <typename ItTy,
862 typename = typename std::enable_if<std::is_convertible<
863 typename std::iterator_traits<ItTy>::iterator_category,
864 std::input_iterator_tag>::value>::type>
865 SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
866 this->append(S, E);
867 }
868
869 template <typename RangeTy>
870 explicit SmallVector(const iterator_range<RangeTy> &R)
871 : SmallVectorImpl<T>(N) {
872 this->append(R.begin(), R.end());
873 }
874
875 SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) {
876 this->assign(IL);
877 }
878
879 SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
880 if (!RHS.empty())
881 SmallVectorImpl<T>::operator=(RHS);
882 }
883
884 const SmallVector &operator=(const SmallVector &RHS) {
885 SmallVectorImpl<T>::operator=(RHS);
886 return *this;
887 }
888
889 SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
890 if (!RHS.empty())
891 SmallVectorImpl<T>::operator=(::std::move(RHS));
892 }
893
894 SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
895 if (!RHS.empty())
896 SmallVectorImpl<T>::operator=(::std::move(RHS));
897 }
898
899 const SmallVector &operator=(SmallVector &&RHS) {
900 SmallVectorImpl<T>::operator=(::std::move(RHS));
901 return *this;
902 }
903
904 const SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
905 SmallVectorImpl<T>::operator=(::std::move(RHS));
906 return *this;
907 }
908
909 const SmallVector &operator=(std::initializer_list<T> IL) {
910 this->assign(IL);
911 return *this;
912 }
913};
914
915template <typename T, unsigned N>
916inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
917 return X.capacity_in_bytes();
918}
919
920} // end namespace llvm
921
922namespace std {
923
924 /// Implement std::swap in terms of SmallVector swap.
925 template<typename T>
926 inline void
927 swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
928 LHS.swap(RHS);
929 }
930
931 /// Implement std::swap in terms of SmallVector swap.
932 template<typename T, unsigned N>
933 inline void
934 swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {
935 LHS.swap(RHS);
936 }
937
938} // end namespace std
939
940#endif // LLVM_ADT_SMALLVECTOR_H
941