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1//===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- 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 contains some templates that are useful if you are working with the
11// STL at all.
12//
13// No library is required when using these functions.
14//
15//===----------------------------------------------------------------------===//
16
17#ifndef LLVM_ADT_STLEXTRAS_H
18#define LLVM_ADT_STLEXTRAS_H
19
20#include "llvm/ADT/Optional.h"
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/ADT/iterator.h"
23#include "llvm/ADT/iterator_range.h"
24#include "llvm/Support/ErrorHandling.h"
25#include <algorithm>
26#include <cassert>
27#include <cstddef>
28#include <cstdint>
29#include <cstdlib>
30#include <functional>
31#include <initializer_list>
32#include <iterator>
33#include <limits>
34#include <memory>
35#include <tuple>
36#include <type_traits>
37#include <utility>
38
39#ifdef EXPENSIVE_CHECKS
40#include <random> // for std::mt19937
41#endif
42
43namespace llvm {
44
45// Only used by compiler if both template types are the same. Useful when
46// using SFINAE to test for the existence of member functions.
47template <typename T, T> struct SameType;
48
49namespace detail {
50
51template <typename RangeT>
52using IterOfRange = decltype(std::begin(std::declval<RangeT &>()));
53
54template <typename RangeT>
55using ValueOfRange = typename std::remove_reference<decltype(
56 *std::begin(std::declval<RangeT &>()))>::type;
57
58} // end namespace detail
59
60//===----------------------------------------------------------------------===//
61// Extra additions to <type_traits>
62//===----------------------------------------------------------------------===//
63
64template <typename T>
65struct negation : std::integral_constant<bool, !bool(T::value)> {};
66
67template <typename...> struct conjunction : std::true_type {};
68template <typename B1> struct conjunction<B1> : B1 {};
69template <typename B1, typename... Bn>
70struct conjunction<B1, Bn...>
71 : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};
72
73//===----------------------------------------------------------------------===//
74// Extra additions to <functional>
75//===----------------------------------------------------------------------===//
76
77template <class Ty> struct identity {
78 using argument_type = Ty;
79
80 Ty &operator()(Ty &self) const {
81 return self;
82 }
83 const Ty &operator()(const Ty &self) const {
84 return self;
85 }
86};
87
88template <class Ty> struct less_ptr {
89 bool operator()(const Ty* left, const Ty* right) const {
90 return *left < *right;
91 }
92};
93
94template <class Ty> struct greater_ptr {
95 bool operator()(const Ty* left, const Ty* right) const {
96 return *right < *left;
97 }
98};
99
100/// An efficient, type-erasing, non-owning reference to a callable. This is
101/// intended for use as the type of a function parameter that is not used
102/// after the function in question returns.
103///
104/// This class does not own the callable, so it is not in general safe to store
105/// a function_ref.
106template<typename Fn> class function_ref;
107
108template<typename Ret, typename ...Params>
109class function_ref<Ret(Params...)> {
110 Ret (*callback)(intptr_t callable, Params ...params) = nullptr;
111 intptr_t callable;
112
113 template<typename Callable>
114 static Ret callback_fn(intptr_t callable, Params ...params) {
115 return (*reinterpret_cast<Callable*>(callable))(
116 std::forward<Params>(params)...);
117 }
118
119public:
120 function_ref() = default;
121 function_ref(std::nullptr_t) {}
122
123 template <typename Callable>
124 function_ref(Callable &&callable,
125 typename std::enable_if<
126 !std::is_same<typename std::remove_reference<Callable>::type,
127 function_ref>::value>::type * = nullptr)
128 : callback(callback_fn<typename std::remove_reference<Callable>::type>),
129 callable(reinterpret_cast<intptr_t>(&callable)) {}
130
131 Ret operator()(Params ...params) const {
132 return callback(callable, std::forward<Params>(params)...);
133 }
134
135 operator bool() const { return callback; }
136};
137
138// deleter - Very very very simple method that is used to invoke operator
139// delete on something. It is used like this:
140//
141// for_each(V.begin(), B.end(), deleter<Interval>);
142template <class T>
143inline void deleter(T *Ptr) {
144 delete Ptr;
145}
146
147//===----------------------------------------------------------------------===//
148// Extra additions to <iterator>
149//===----------------------------------------------------------------------===//
150
151namespace adl_detail {
152
153using std::begin;
154
155template <typename ContainerTy>
156auto adl_begin(ContainerTy &&container)
157 -> decltype(begin(std::forward<ContainerTy>(container))) {
158 return begin(std::forward<ContainerTy>(container));
159}
160
161using std::end;
162
163template <typename ContainerTy>
164auto adl_end(ContainerTy &&container)
165 -> decltype(end(std::forward<ContainerTy>(container))) {
166 return end(std::forward<ContainerTy>(container));
167}
168
169using std::swap;
170
171template <typename T>
172void adl_swap(T &&lhs, T &&rhs) noexcept(noexcept(swap(std::declval<T>(),
173 std::declval<T>()))) {
174 swap(std::forward<T>(lhs), std::forward<T>(rhs));
175}
176
177} // end namespace adl_detail
178
179template <typename ContainerTy>
180auto adl_begin(ContainerTy &&container)
181 -> decltype(adl_detail::adl_begin(std::forward<ContainerTy>(container))) {
182 return adl_detail::adl_begin(std::forward<ContainerTy>(container));
183}
184
185template <typename ContainerTy>
186auto adl_end(ContainerTy &&container)
187 -> decltype(adl_detail::adl_end(std::forward<ContainerTy>(container))) {
188 return adl_detail::adl_end(std::forward<ContainerTy>(container));
189}
190
191template <typename T>
192void adl_swap(T &&lhs, T &&rhs) noexcept(
193 noexcept(adl_detail::adl_swap(std::declval<T>(), std::declval<T>()))) {
194 adl_detail::adl_swap(std::forward<T>(lhs), std::forward<T>(rhs));
195}
196
197// mapped_iterator - This is a simple iterator adapter that causes a function to
198// be applied whenever operator* is invoked on the iterator.
199
200template <typename ItTy, typename FuncTy,
201 typename FuncReturnTy =
202 decltype(std::declval<FuncTy>()(*std::declval<ItTy>()))>
203class mapped_iterator
204 : public iterator_adaptor_base<
205 mapped_iterator<ItTy, FuncTy>, ItTy,
206 typename std::iterator_traits<ItTy>::iterator_category,
207 typename std::remove_reference<FuncReturnTy>::type> {
208public:
209 mapped_iterator(ItTy U, FuncTy F)
210 : mapped_iterator::iterator_adaptor_base(std::move(U)), F(std::move(F)) {}
211
212 ItTy getCurrent() { return this->I; }
213
214 FuncReturnTy operator*() { return F(*this->I); }
215
216private:
217 FuncTy F;
218};
219
220// map_iterator - Provide a convenient way to create mapped_iterators, just like
221// make_pair is useful for creating pairs...
222template <class ItTy, class FuncTy>
223inline mapped_iterator<ItTy, FuncTy> map_iterator(ItTy I, FuncTy F) {
224 return mapped_iterator<ItTy, FuncTy>(std::move(I), std::move(F));
225}
226
227/// Helper to determine if type T has a member called rbegin().
228template <typename Ty> class has_rbegin_impl {
229 using yes = char[1];
230 using no = char[2];
231
232 template <typename Inner>
233 static yes& test(Inner *I, decltype(I->rbegin()) * = nullptr);
234
235 template <typename>
236 static no& test(...);
237
238public:
239 static const bool value = sizeof(test<Ty>(nullptr)) == sizeof(yes);
240};
241
242/// Metafunction to determine if T& or T has a member called rbegin().
243template <typename Ty>
244struct has_rbegin : has_rbegin_impl<typename std::remove_reference<Ty>::type> {
245};
246
247// Returns an iterator_range over the given container which iterates in reverse.
248// Note that the container must have rbegin()/rend() methods for this to work.
249template <typename ContainerTy>
250auto reverse(ContainerTy &&C,
251 typename std::enable_if<has_rbegin<ContainerTy>::value>::type * =
252 nullptr) -> decltype(make_range(C.rbegin(), C.rend())) {
253 return make_range(C.rbegin(), C.rend());
254}
255
256// Returns a std::reverse_iterator wrapped around the given iterator.
257template <typename IteratorTy>
258std::reverse_iterator<IteratorTy> make_reverse_iterator(IteratorTy It) {
259 return std::reverse_iterator<IteratorTy>(It);
260}
261
262// Returns an iterator_range over the given container which iterates in reverse.
263// Note that the container must have begin()/end() methods which return
264// bidirectional iterators for this to work.
265template <typename ContainerTy>
266auto reverse(
267 ContainerTy &&C,
268 typename std::enable_if<!has_rbegin<ContainerTy>::value>::type * = nullptr)
269 -> decltype(make_range(llvm::make_reverse_iterator(std::end(C)),
270 llvm::make_reverse_iterator(std::begin(C)))) {
271 return make_range(llvm::make_reverse_iterator(std::end(C)),
272 llvm::make_reverse_iterator(std::begin(C)));
273}
274
275/// An iterator adaptor that filters the elements of given inner iterators.
276///
277/// The predicate parameter should be a callable object that accepts the wrapped
278/// iterator's reference type and returns a bool. When incrementing or
279/// decrementing the iterator, it will call the predicate on each element and
280/// skip any where it returns false.
281///
282/// \code
283/// int A[] = { 1, 2, 3, 4 };
284/// auto R = make_filter_range(A, [](int N) { return N % 2 == 1; });
285/// // R contains { 1, 3 }.
286/// \endcode
287///
288/// Note: filter_iterator_base implements support for forward iteration.
289/// filter_iterator_impl exists to provide support for bidirectional iteration,
290/// conditional on whether the wrapped iterator supports it.
291template <typename WrappedIteratorT, typename PredicateT, typename IterTag>
292class filter_iterator_base
293 : public iterator_adaptor_base<
294 filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>,
295 WrappedIteratorT,
296 typename std::common_type<
297 IterTag, typename std::iterator_traits<
298 WrappedIteratorT>::iterator_category>::type> {
299 using BaseT = iterator_adaptor_base<
300 filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>,
301 WrappedIteratorT,
302 typename std::common_type<
303 IterTag, typename std::iterator_traits<
304 WrappedIteratorT>::iterator_category>::type>;
305
306protected:
307 WrappedIteratorT End;
308 PredicateT Pred;
309
310 void findNextValid() {
311 while (this->I != End && !Pred(*this->I))
312 BaseT::operator++();
313 }
314
315 // Construct the iterator. The begin iterator needs to know where the end
316 // is, so that it can properly stop when it gets there. The end iterator only
317 // needs the predicate to support bidirectional iteration.
318 filter_iterator_base(WrappedIteratorT Begin, WrappedIteratorT End,
319 PredicateT Pred)
320 : BaseT(Begin), End(End), Pred(Pred) {
321 findNextValid();
322 }
323
324public:
325 using BaseT::operator++;
326
327 filter_iterator_base &operator++() {
328 BaseT::operator++();
329 findNextValid();
330 return *this;
331 }
332};
333
334/// Specialization of filter_iterator_base for forward iteration only.
335template <typename WrappedIteratorT, typename PredicateT,
336 typename IterTag = std::forward_iterator_tag>
337class filter_iterator_impl
338 : public filter_iterator_base<WrappedIteratorT, PredicateT, IterTag> {
339 using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>;
340
341public:
342 filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
343 PredicateT Pred)
344 : BaseT(Begin, End, Pred) {}
345};
346
347/// Specialization of filter_iterator_base for bidirectional iteration.
348template <typename WrappedIteratorT, typename PredicateT>
349class filter_iterator_impl<WrappedIteratorT, PredicateT,
350 std::bidirectional_iterator_tag>
351 : public filter_iterator_base<WrappedIteratorT, PredicateT,
352 std::bidirectional_iterator_tag> {
353 using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT,
354 std::bidirectional_iterator_tag>;
355 void findPrevValid() {
356 while (!this->Pred(*this->I))
357 BaseT::operator--();
358 }
359
360public:
361 using BaseT::operator--;
362
363 filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
364 PredicateT Pred)
365 : BaseT(Begin, End, Pred) {}
366
367 filter_iterator_impl &operator--() {
368 BaseT::operator--();
369 findPrevValid();
370 return *this;
371 }
372};
373
374namespace detail {
375
376template <bool is_bidirectional> struct fwd_or_bidi_tag_impl {
377 using type = std::forward_iterator_tag;
378};
379
380template <> struct fwd_or_bidi_tag_impl<true> {
381 using type = std::bidirectional_iterator_tag;
382};
383
384/// Helper which sets its type member to forward_iterator_tag if the category
385/// of \p IterT does not derive from bidirectional_iterator_tag, and to
386/// bidirectional_iterator_tag otherwise.
387template <typename IterT> struct fwd_or_bidi_tag {
388 using type = typename fwd_or_bidi_tag_impl<std::is_base_of<
389 std::bidirectional_iterator_tag,
390 typename std::iterator_traits<IterT>::iterator_category>::value>::type;
391};
392
393} // namespace detail
394
395/// Defines filter_iterator to a suitable specialization of
396/// filter_iterator_impl, based on the underlying iterator's category.
397template <typename WrappedIteratorT, typename PredicateT>
398using filter_iterator = filter_iterator_impl<
399 WrappedIteratorT, PredicateT,
400 typename detail::fwd_or_bidi_tag<WrappedIteratorT>::type>;
401
402/// Convenience function that takes a range of elements and a predicate,
403/// and return a new filter_iterator range.
404///
405/// FIXME: Currently if RangeT && is a rvalue reference to a temporary, the
406/// lifetime of that temporary is not kept by the returned range object, and the
407/// temporary is going to be dropped on the floor after the make_iterator_range
408/// full expression that contains this function call.
409template <typename RangeT, typename PredicateT>
410iterator_range<filter_iterator<detail::IterOfRange<RangeT>, PredicateT>>
411make_filter_range(RangeT &&Range, PredicateT Pred) {
412 using FilterIteratorT =
413 filter_iterator<detail::IterOfRange<RangeT>, PredicateT>;
414 return make_range(
415 FilterIteratorT(std::begin(std::forward<RangeT>(Range)),
416 std::end(std::forward<RangeT>(Range)), Pred),
417 FilterIteratorT(std::end(std::forward<RangeT>(Range)),
418 std::end(std::forward<RangeT>(Range)), Pred));
419}
420
421// forward declarations required by zip_shortest/zip_first
422template <typename R, typename UnaryPredicate>
423bool all_of(R &&range, UnaryPredicate P);
424
425template <size_t... I> struct index_sequence;
426
427template <class... Ts> struct index_sequence_for;
428
429namespace detail {
430
431using std::declval;
432
433// We have to alias this since inlining the actual type at the usage site
434// in the parameter list of iterator_facade_base<> below ICEs MSVC 2017.
435template<typename... Iters> struct ZipTupleType {
436 using type = std::tuple<decltype(*declval<Iters>())...>;
437};
438
439template <typename ZipType, typename... Iters>
440using zip_traits = iterator_facade_base<
441 ZipType, typename std::common_type<std::bidirectional_iterator_tag,
442 typename std::iterator_traits<
443 Iters>::iterator_category...>::type,
444 // ^ TODO: Implement random access methods.
445 typename ZipTupleType<Iters...>::type,
446 typename std::iterator_traits<typename std::tuple_element<
447 0, std::tuple<Iters...>>::type>::difference_type,
448 // ^ FIXME: This follows boost::make_zip_iterator's assumption that all
449 // inner iterators have the same difference_type. It would fail if, for
450 // instance, the second field's difference_type were non-numeric while the
451 // first is.
452 typename ZipTupleType<Iters...>::type *,
453 typename ZipTupleType<Iters...>::type>;
454
455template <typename ZipType, typename... Iters>
456struct zip_common : public zip_traits<ZipType, Iters...> {
457 using Base = zip_traits<ZipType, Iters...>;
458 using value_type = typename Base::value_type;
459
460 std::tuple<Iters...> iterators;
461
462protected:
463 template <size_t... Ns> value_type deref(index_sequence<Ns...>) const {
464 return value_type(*std::get<Ns>(iterators)...);
465 }
466
467 template <size_t... Ns>
468 decltype(iterators) tup_inc(index_sequence<Ns...>) const {
469 return std::tuple<Iters...>(std::next(std::get<Ns>(iterators))...);
470 }
471
472 template <size_t... Ns>
473 decltype(iterators) tup_dec(index_sequence<Ns...>) const {
474 return std::tuple<Iters...>(std::prev(std::get<Ns>(iterators))...);
475 }
476
477public:
478 zip_common(Iters &&... ts) : iterators(std::forward<Iters>(ts)...) {}
479
480 value_type operator*() { return deref(index_sequence_for<Iters...>{}); }
481
482 const value_type operator*() const {
483 return deref(index_sequence_for<Iters...>{});
484 }
485
486 ZipType &operator++() {
487 iterators = tup_inc(index_sequence_for<Iters...>{});
488 return *reinterpret_cast<ZipType *>(this);
489 }
490
491 ZipType &operator--() {
492 static_assert(Base::IsBidirectional,
493 "All inner iterators must be at least bidirectional.");
494 iterators = tup_dec(index_sequence_for<Iters...>{});
495 return *reinterpret_cast<ZipType *>(this);
496 }
497};
498
499template <typename... Iters>
500struct zip_first : public zip_common<zip_first<Iters...>, Iters...> {
501 using Base = zip_common<zip_first<Iters...>, Iters...>;
502
503 bool operator==(const zip_first<Iters...> &other) const {
504 return std::get<0>(this->iterators) == std::get<0>(other.iterators);
505 }
506
507 zip_first(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
508};
509
510template <typename... Iters>
511class zip_shortest : public zip_common<zip_shortest<Iters...>, Iters...> {
512 template <size_t... Ns>
513 bool test(const zip_shortest<Iters...> &other, index_sequence<Ns...>) const {
514 return all_of(std::initializer_list<bool>{std::get<Ns>(this->iterators) !=
515 std::get<Ns>(other.iterators)...},
516 identity<bool>{});
517 }
518
519public:
520 using Base = zip_common<zip_shortest<Iters...>, Iters...>;
521
522 zip_shortest(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
523
524 bool operator==(const zip_shortest<Iters...> &other) const {
525 return !test(other, index_sequence_for<Iters...>{});
526 }
527};
528
529template <template <typename...> class ItType, typename... Args> class zippy {
530public:
531 using iterator = ItType<decltype(std::begin(std::declval<Args>()))...>;
532 using iterator_category = typename iterator::iterator_category;
533 using value_type = typename iterator::value_type;
534 using difference_type = typename iterator::difference_type;
535 using pointer = typename iterator::pointer;
536 using reference = typename iterator::reference;
537
538private:
539 std::tuple<Args...> ts;
540
541 template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) const {
542 return iterator(std::begin(std::get<Ns>(ts))...);
543 }
544 template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) const {
545 return iterator(std::end(std::get<Ns>(ts))...);
546 }
547
548public:
549 zippy(Args &&... ts_) : ts(std::forward<Args>(ts_)...) {}
550
551 iterator begin() const { return begin_impl(index_sequence_for<Args...>{}); }
552 iterator end() const { return end_impl(index_sequence_for<Args...>{}); }
553};
554
555} // end namespace detail
556
557/// zip iterator for two or more iteratable types.
558template <typename T, typename U, typename... Args>
559detail::zippy<detail::zip_shortest, T, U, Args...> zip(T &&t, U &&u,
560 Args &&... args) {
561 return detail::zippy<detail::zip_shortest, T, U, Args...>(
562 std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
563}
564
565/// zip iterator that, for the sake of efficiency, assumes the first iteratee to
566/// be the shortest.
567template <typename T, typename U, typename... Args>
568detail::zippy<detail::zip_first, T, U, Args...> zip_first(T &&t, U &&u,
569 Args &&... args) {
570 return detail::zippy<detail::zip_first, T, U, Args...>(
571 std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
572}
573
574/// Iterator wrapper that concatenates sequences together.
575///
576/// This can concatenate different iterators, even with different types, into
577/// a single iterator provided the value types of all the concatenated
578/// iterators expose `reference` and `pointer` types that can be converted to
579/// `ValueT &` and `ValueT *` respectively. It doesn't support more
580/// interesting/customized pointer or reference types.
581///
582/// Currently this only supports forward or higher iterator categories as
583/// inputs and always exposes a forward iterator interface.
584template <typename ValueT, typename... IterTs>
585class concat_iterator
586 : public iterator_facade_base<concat_iterator<ValueT, IterTs...>,
587 std::forward_iterator_tag, ValueT> {
588 using BaseT = typename concat_iterator::iterator_facade_base;
589
590 /// We store both the current and end iterators for each concatenated
591 /// sequence in a tuple of pairs.
592 ///
593 /// Note that something like iterator_range seems nice at first here, but the
594 /// range properties are of little benefit and end up getting in the way
595 /// because we need to do mutation on the current iterators.
596 std::tuple<std::pair<IterTs, IterTs>...> IterPairs;
597
598 /// Attempts to increment a specific iterator.
599 ///
600 /// Returns true if it was able to increment the iterator. Returns false if
601 /// the iterator is already at the end iterator.
602 template <size_t Index> bool incrementHelper() {
603 auto &IterPair = std::get<Index>(IterPairs);
604 if (IterPair.first == IterPair.second)
605 return false;
606
607 ++IterPair.first;
608 return true;
609 }
610
611 /// Increments the first non-end iterator.
612 ///
613 /// It is an error to call this with all iterators at the end.
614 template <size_t... Ns> void increment(index_sequence<Ns...>) {
615 // Build a sequence of functions to increment each iterator if possible.
616 bool (concat_iterator::*IncrementHelperFns[])() = {
617 &concat_iterator::incrementHelper<Ns>...};
618
619 // Loop over them, and stop as soon as we succeed at incrementing one.
620 for (auto &IncrementHelperFn : IncrementHelperFns)
621 if ((this->*IncrementHelperFn)())
622 return;
623
624 llvm_unreachable("Attempted to increment an end concat iterator!");
625 }
626
627 /// Returns null if the specified iterator is at the end. Otherwise,
628 /// dereferences the iterator and returns the address of the resulting
629 /// reference.
630 template <size_t Index> ValueT *getHelper() const {
631 auto &IterPair = std::get<Index>(IterPairs);
632 if (IterPair.first == IterPair.second)
633 return nullptr;
634
635 return &*IterPair.first;
636 }
637
638 /// Finds the first non-end iterator, dereferences, and returns the resulting
639 /// reference.
640 ///
641 /// It is an error to call this with all iterators at the end.
642 template <size_t... Ns> ValueT &get(index_sequence<Ns...>) const {
643 // Build a sequence of functions to get from iterator if possible.
644 ValueT *(concat_iterator::*GetHelperFns[])() const = {
645 &concat_iterator::getHelper<Ns>...};
646
647 // Loop over them, and return the first result we find.
648 for (auto &GetHelperFn : GetHelperFns)
649 if (ValueT *P = (this->*GetHelperFn)())
650 return *P;
651
652 llvm_unreachable("Attempted to get a pointer from an end concat iterator!");
653 }
654
655public:
656 /// Constructs an iterator from a squence of ranges.
657 ///
658 /// We need the full range to know how to switch between each of the
659 /// iterators.
660 template <typename... RangeTs>
661 explicit concat_iterator(RangeTs &&... Ranges)
662 : IterPairs({std::begin(Ranges), std::end(Ranges)}...) {}
663
664 using BaseT::operator++;
665
666 concat_iterator &operator++() {
667 increment(index_sequence_for<IterTs...>());
668 return *this;
669 }
670
671 ValueT &operator*() const { return get(index_sequence_for<IterTs...>()); }
672
673 bool operator==(const concat_iterator &RHS) const {
674 return IterPairs == RHS.IterPairs;
675 }
676};
677
678namespace detail {
679
680/// Helper to store a sequence of ranges being concatenated and access them.
681///
682/// This is designed to facilitate providing actual storage when temporaries
683/// are passed into the constructor such that we can use it as part of range
684/// based for loops.
685template <typename ValueT, typename... RangeTs> class concat_range {
686public:
687 using iterator =
688 concat_iterator<ValueT,
689 decltype(std::begin(std::declval<RangeTs &>()))...>;
690
691private:
692 std::tuple<RangeTs...> Ranges;
693
694 template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) {
695 return iterator(std::get<Ns>(Ranges)...);
696 }
697 template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) {
698 return iterator(make_range(std::end(std::get<Ns>(Ranges)),
699 std::end(std::get<Ns>(Ranges)))...);
700 }
701
702public:
703 concat_range(RangeTs &&... Ranges)
704 : Ranges(std::forward<RangeTs>(Ranges)...) {}
705
706 iterator begin() { return begin_impl(index_sequence_for<RangeTs...>{}); }
707 iterator end() { return end_impl(index_sequence_for<RangeTs...>{}); }
708};
709
710} // end namespace detail
711
712/// Concatenated range across two or more ranges.
713///
714/// The desired value type must be explicitly specified.
715template <typename ValueT, typename... RangeTs>
716detail::concat_range<ValueT, RangeTs...> concat(RangeTs &&... Ranges) {
717 static_assert(sizeof...(RangeTs) > 1,
718 "Need more than one range to concatenate!");
719 return detail::concat_range<ValueT, RangeTs...>(
720 std::forward<RangeTs>(Ranges)...);
721}
722
723//===----------------------------------------------------------------------===//
724// Extra additions to <utility>
725//===----------------------------------------------------------------------===//
726
727/// Function object to check whether the first component of a std::pair
728/// compares less than the first component of another std::pair.
729struct less_first {
730 template <typename T> bool operator()(const T &lhs, const T &rhs) const {
731 return lhs.first < rhs.first;
732 }
733};
734
735/// Function object to check whether the second component of a std::pair
736/// compares less than the second component of another std::pair.
737struct less_second {
738 template <typename T> bool operator()(const T &lhs, const T &rhs) const {
739 return lhs.second < rhs.second;
740 }
741};
742
743// A subset of N3658. More stuff can be added as-needed.
744
745/// Represents a compile-time sequence of integers.
746template <class T, T... I> struct integer_sequence {
747 using value_type = T;
748
749 static constexpr size_t size() { return sizeof...(I); }
750};
751
752/// Alias for the common case of a sequence of size_ts.
753template <size_t... I>
754struct index_sequence : integer_sequence<std::size_t, I...> {};
755
756template <std::size_t N, std::size_t... I>
757struct build_index_impl : build_index_impl<N - 1, N - 1, I...> {};
758template <std::size_t... I>
759struct build_index_impl<0, I...> : index_sequence<I...> {};
760
761/// Creates a compile-time integer sequence for a parameter pack.
762template <class... Ts>
763struct index_sequence_for : build_index_impl<sizeof...(Ts)> {};
764
765/// Utility type to build an inheritance chain that makes it easy to rank
766/// overload candidates.
767template <int N> struct rank : rank<N - 1> {};
768template <> struct rank<0> {};
769
770/// traits class for checking whether type T is one of any of the given
771/// types in the variadic list.
772template <typename T, typename... Ts> struct is_one_of {
773 static const bool value = false;
774};
775
776template <typename T, typename U, typename... Ts>
777struct is_one_of<T, U, Ts...> {
778 static const bool value =
779 std::is_same<T, U>::value || is_one_of<T, Ts...>::value;
780};
781
782/// traits class for checking whether type T is a base class for all
783/// the given types in the variadic list.
784template <typename T, typename... Ts> struct are_base_of {
785 static const bool value = true;
786};
787
788template <typename T, typename U, typename... Ts>
789struct are_base_of<T, U, Ts...> {
790 static const bool value =
791 std::is_base_of<T, U>::value && are_base_of<T, Ts...>::value;
792};
793
794//===----------------------------------------------------------------------===//
795// Extra additions for arrays
796//===----------------------------------------------------------------------===//
797
798/// Find the length of an array.
799template <class T, std::size_t N>
800constexpr inline size_t array_lengthof(T (&)[N]) {
801 return N;
802}
803
804/// Adapt std::less<T> for array_pod_sort.
805template<typename T>
806inline int array_pod_sort_comparator(const void *P1, const void *P2) {
807 if (std::less<T>()(*reinterpret_cast<const T*>(P1),
808 *reinterpret_cast<const T*>(P2)))
809 return -1;
810 if (std::less<T>()(*reinterpret_cast<const T*>(P2),
811 *reinterpret_cast<const T*>(P1)))
812 return 1;
813 return 0;
814}
815
816/// get_array_pod_sort_comparator - This is an internal helper function used to
817/// get type deduction of T right.
818template<typename T>
819inline int (*get_array_pod_sort_comparator(const T &))
820 (const void*, const void*) {
821 return array_pod_sort_comparator<T>;
822}
823
824/// array_pod_sort - This sorts an array with the specified start and end
825/// extent. This is just like std::sort, except that it calls qsort instead of
826/// using an inlined template. qsort is slightly slower than std::sort, but
827/// most sorts are not performance critical in LLVM and std::sort has to be
828/// template instantiated for each type, leading to significant measured code
829/// bloat. This function should generally be used instead of std::sort where
830/// possible.
831///
832/// This function assumes that you have simple POD-like types that can be
833/// compared with std::less and can be moved with memcpy. If this isn't true,
834/// you should use std::sort.
835///
836/// NOTE: If qsort_r were portable, we could allow a custom comparator and
837/// default to std::less.
838template<class IteratorTy>
839inline void array_pod_sort(IteratorTy Start, IteratorTy End) {
840 // Don't inefficiently call qsort with one element or trigger undefined
841 // behavior with an empty sequence.
842 auto NElts = End - Start;
843 if (NElts <= 1) return;
844#ifdef EXPENSIVE_CHECKS
845 std::mt19937 Generator(std::random_device{}());
846 std::shuffle(Start, End, Generator);
847#endif
848 qsort(&*Start, NElts, sizeof(*Start), get_array_pod_sort_comparator(*Start));
849}
850
851template <class IteratorTy>
852inline void array_pod_sort(
853 IteratorTy Start, IteratorTy End,
854 int (*Compare)(
855 const typename std::iterator_traits<IteratorTy>::value_type *,
856 const typename std::iterator_traits<IteratorTy>::value_type *)) {
857 // Don't inefficiently call qsort with one element or trigger undefined
858 // behavior with an empty sequence.
859 auto NElts = End - Start;
860 if (NElts <= 1) return;
861#ifdef EXPENSIVE_CHECKS
862 std::mt19937 Generator(std::random_device{}());
863 std::shuffle(Start, End, Generator);
864#endif
865 qsort(&*Start, NElts, sizeof(*Start),
866 reinterpret_cast<int (*)(const void *, const void *)>(Compare));
867}
868
869// Provide wrappers to std::sort which shuffle the elements before sorting
870// to help uncover non-deterministic behavior (PR35135).
871template <typename IteratorTy>
872inline void sort(IteratorTy Start, IteratorTy End) {
873#ifdef EXPENSIVE_CHECKS
874 std::mt19937 Generator(std::random_device{}());
875 std::shuffle(Start, End, Generator);
876#endif
877 std::sort(Start, End);
878}
879
880template <typename IteratorTy, typename Compare>
881inline void sort(IteratorTy Start, IteratorTy End, Compare Comp) {
882#ifdef EXPENSIVE_CHECKS
883 std::mt19937 Generator(std::random_device{}());
884 std::shuffle(Start, End, Generator);
885#endif
886 std::sort(Start, End, Comp);
887}
888
889//===----------------------------------------------------------------------===//
890// Extra additions to <algorithm>
891//===----------------------------------------------------------------------===//
892
893/// For a container of pointers, deletes the pointers and then clears the
894/// container.
895template<typename Container>
896void DeleteContainerPointers(Container &C) {
897 for (auto V : C)
898 delete V;
899 C.clear();
900}
901
902/// In a container of pairs (usually a map) whose second element is a pointer,
903/// deletes the second elements and then clears the container.
904template<typename Container>
905void DeleteContainerSeconds(Container &C) {
906 for (auto &V : C)
907 delete V.second;
908 C.clear();
909}
910
911/// Provide wrappers to std::for_each which take ranges instead of having to
912/// pass begin/end explicitly.
913template <typename R, typename UnaryPredicate>
914UnaryPredicate for_each(R &&Range, UnaryPredicate P) {
915 return std::for_each(adl_begin(Range), adl_end(Range), P);
916}
917
918/// Provide wrappers to std::all_of which take ranges instead of having to pass
919/// begin/end explicitly.
920template <typename R, typename UnaryPredicate>
921bool all_of(R &&Range, UnaryPredicate P) {
922 return std::all_of(adl_begin(Range), adl_end(Range), P);
923}
924
925/// Provide wrappers to std::any_of which take ranges instead of having to pass
926/// begin/end explicitly.
927template <typename R, typename UnaryPredicate>
928bool any_of(R &&Range, UnaryPredicate P) {
929 return std::any_of(adl_begin(Range), adl_end(Range), P);
930}
931
932/// Provide wrappers to std::none_of which take ranges instead of having to pass
933/// begin/end explicitly.
934template <typename R, typename UnaryPredicate>
935bool none_of(R &&Range, UnaryPredicate P) {
936 return std::none_of(adl_begin(Range), adl_end(Range), P);
937}
938
939/// Provide wrappers to std::find which take ranges instead of having to pass
940/// begin/end explicitly.
941template <typename R, typename T>
942auto find(R &&Range, const T &Val) -> decltype(adl_begin(Range)) {
943 return std::find(adl_begin(Range), adl_end(Range), Val);
944}
945
946/// Provide wrappers to std::find_if which take ranges instead of having to pass
947/// begin/end explicitly.
948template <typename R, typename UnaryPredicate>
949auto find_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
950 return std::find_if(adl_begin(Range), adl_end(Range), P);
951}
952
953template <typename R, typename UnaryPredicate>
954auto find_if_not(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
955 return std::find_if_not(adl_begin(Range), adl_end(Range), P);
956}
957
958/// Provide wrappers to std::remove_if which take ranges instead of having to
959/// pass begin/end explicitly.
960template <typename R, typename UnaryPredicate>
961auto remove_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
962 return std::remove_if(adl_begin(Range), adl_end(Range), P);
963}
964
965/// Provide wrappers to std::copy_if which take ranges instead of having to
966/// pass begin/end explicitly.
967template <typename R, typename OutputIt, typename UnaryPredicate>
968OutputIt copy_if(R &&Range, OutputIt Out, UnaryPredicate P) {
969 return std::copy_if(adl_begin(Range), adl_end(Range), Out, P);
970}
971
972template <typename R, typename OutputIt>
973OutputIt copy(R &&Range, OutputIt Out) {
974 return std::copy(adl_begin(Range), adl_end(Range), Out);
975}
976
977/// Wrapper function around std::find to detect if an element exists
978/// in a container.
979template <typename R, typename E>
980bool is_contained(R &&Range, const E &Element) {
981 return std::find(adl_begin(Range), adl_end(Range), Element) != adl_end(Range);
982}
983
984/// Wrapper function around std::count to count the number of times an element
985/// \p Element occurs in the given range \p Range.
986template <typename R, typename E>
987auto count(R &&Range, const E &Element) ->
988 typename std::iterator_traits<decltype(adl_begin(Range))>::difference_type {
989 return std::count(adl_begin(Range), adl_end(Range), Element);
990}
991
992/// Wrapper function around std::count_if to count the number of times an
993/// element satisfying a given predicate occurs in a range.
994template <typename R, typename UnaryPredicate>
995auto count_if(R &&Range, UnaryPredicate P) ->
996 typename std::iterator_traits<decltype(adl_begin(Range))>::difference_type {
997 return std::count_if(adl_begin(Range), adl_end(Range), P);
998}
999
1000/// Wrapper function around std::transform to apply a function to a range and
1001/// store the result elsewhere.
1002template <typename R, typename OutputIt, typename UnaryPredicate>
1003OutputIt transform(R &&Range, OutputIt d_first, UnaryPredicate P) {
1004 return std::transform(adl_begin(Range), adl_end(Range), d_first, P);
1005}
1006
1007/// Provide wrappers to std::partition which take ranges instead of having to
1008/// pass begin/end explicitly.
1009template <typename R, typename UnaryPredicate>
1010auto partition(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1011 return std::partition(adl_begin(Range), adl_end(Range), P);
1012}
1013
1014/// Provide wrappers to std::lower_bound which take ranges instead of having to
1015/// pass begin/end explicitly.
1016template <typename R, typename ForwardIt>
1017auto lower_bound(R &&Range, ForwardIt I) -> decltype(adl_begin(Range)) {
1018 return std::lower_bound(adl_begin(Range), adl_end(Range), I);
1019}
1020
1021/// Given a range of type R, iterate the entire range and return a
1022/// SmallVector with elements of the vector. This is useful, for example,
1023/// when you want to iterate a range and then sort the results.
1024template <unsigned Size, typename R>
1025SmallVector<typename std::remove_const<detail::ValueOfRange<R>>::type, Size>
1026to_vector(R &&Range) {
1027 return {adl_begin(Range), adl_end(Range)};
1028}
1029
1030/// Provide a container algorithm similar to C++ Library Fundamentals v2's
1031/// `erase_if` which is equivalent to:
1032///
1033/// C.erase(remove_if(C, pred), C.end());
1034///
1035/// This version works for any container with an erase method call accepting
1036/// two iterators.
1037template <typename Container, typename UnaryPredicate>
1038void erase_if(Container &C, UnaryPredicate P) {
1039 C.erase(remove_if(C, P), C.end());
1040}
1041
1042/// Get the size of a range. This is a wrapper function around std::distance
1043/// which is only enabled when the operation is O(1).
1044template <typename R>
1045auto size(R &&Range, typename std::enable_if<
1046 std::is_same<typename std::iterator_traits<decltype(
1047 Range.begin())>::iterator_category,
1048 std::random_access_iterator_tag>::value,
1049 void>::type * = nullptr)
1050 -> decltype(std::distance(Range.begin(), Range.end())) {
1051 return std::distance(Range.begin(), Range.end());
1052}
1053
1054//===----------------------------------------------------------------------===//
1055// Extra additions to <memory>
1056//===----------------------------------------------------------------------===//
1057
1058// Implement make_unique according to N3656.
1059
1060/// Constructs a `new T()` with the given args and returns a
1061/// `unique_ptr<T>` which owns the object.
1062///
1063/// Example:
1064///
1065/// auto p = make_unique<int>();
1066/// auto p = make_unique<std::tuple<int, int>>(0, 1);
1067template <class T, class... Args>
1068typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
1069make_unique(Args &&... args) {
1070 return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
1071}
1072
1073/// Constructs a `new T[n]` with the given args and returns a
1074/// `unique_ptr<T[]>` which owns the object.
1075///
1076/// \param n size of the new array.
1077///
1078/// Example:
1079///
1080/// auto p = make_unique<int[]>(2); // value-initializes the array with 0's.
1081template <class T>
1082typename std::enable_if<std::is_array<T>::value && std::extent<T>::value == 0,
1083 std::unique_ptr<T>>::type
1084make_unique(size_t n) {
1085 return std::unique_ptr<T>(new typename std::remove_extent<T>::type[n]());
1086}
1087
1088/// This function isn't used and is only here to provide better compile errors.
1089template <class T, class... Args>
1090typename std::enable_if<std::extent<T>::value != 0>::type
1091make_unique(Args &&...) = delete;
1092
1093struct FreeDeleter {
1094 void operator()(void* v) {
1095 ::free(v);
1096 }
1097};
1098
1099template<typename First, typename Second>
1100struct pair_hash {
1101 size_t operator()(const std::pair<First, Second> &P) const {
1102 return std::hash<First>()(P.first) * 31 + std::hash<Second>()(P.second);
1103 }
1104};
1105
1106/// A functor like C++14's std::less<void> in its absence.
1107struct less {
1108 template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1109 return std::forward<A>(a) < std::forward<B>(b);
1110 }
1111};
1112
1113/// A functor like C++14's std::equal<void> in its absence.
1114struct equal {
1115 template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1116 return std::forward<A>(a) == std::forward<B>(b);
1117 }
1118};
1119
1120/// Binary functor that adapts to any other binary functor after dereferencing
1121/// operands.
1122template <typename T> struct deref {
1123 T func;
1124
1125 // Could be further improved to cope with non-derivable functors and
1126 // non-binary functors (should be a variadic template member function
1127 // operator()).
1128 template <typename A, typename B>
1129 auto operator()(A &lhs, B &rhs) const -> decltype(func(*lhs, *rhs)) {
1130 assert(lhs);
1131 assert(rhs);
1132 return func(*lhs, *rhs);
1133 }
1134};
1135
1136namespace detail {
1137
1138template <typename R> class enumerator_iter;
1139
1140template <typename R> struct result_pair {
1141 friend class enumerator_iter<R>;
1142
1143 result_pair() = default;
1144 result_pair(std::size_t Index, IterOfRange<R> Iter)
1145 : Index(Index), Iter(Iter) {}
1146
1147 result_pair<R> &operator=(const result_pair<R> &Other) {
1148 Index = Other.Index;
1149 Iter = Other.Iter;
1150 return *this;
1151 }
1152
1153 std::size_t index() const { return Index; }
1154 const ValueOfRange<R> &value() const { return *Iter; }
1155 ValueOfRange<R> &value() { return *Iter; }
1156
1157private:
1158 std::size_t Index = std::numeric_limits<std::size_t>::max();
1159 IterOfRange<R> Iter;
1160};
1161
1162template <typename R>
1163class enumerator_iter
1164 : public iterator_facade_base<
1165 enumerator_iter<R>, std::forward_iterator_tag, result_pair<R>,
1166 typename std::iterator_traits<IterOfRange<R>>::difference_type,
1167 typename std::iterator_traits<IterOfRange<R>>::pointer,
1168 typename std::iterator_traits<IterOfRange<R>>::reference> {
1169 using result_type = result_pair<R>;
1170
1171public:
1172 explicit enumerator_iter(IterOfRange<R> EndIter)
1173 : Result(std::numeric_limits<size_t>::max(), EndIter) {}
1174
1175 enumerator_iter(std::size_t Index, IterOfRange<R> Iter)
1176 : Result(Index, Iter) {}
1177
1178 result_type &operator*() { return Result; }
1179 const result_type &operator*() const { return Result; }
1180
1181 enumerator_iter<R> &operator++() {
1182 assert(Result.Index != std::numeric_limits<size_t>::max());
1183 ++Result.Iter;
1184 ++Result.Index;
1185 return *this;
1186 }
1187
1188 bool operator==(const enumerator_iter<R> &RHS) const {
1189 // Don't compare indices here, only iterators. It's possible for an end
1190 // iterator to have different indices depending on whether it was created
1191 // by calling std::end() versus incrementing a valid iterator.
1192 return Result.Iter == RHS.Result.Iter;
1193 }
1194
1195 enumerator_iter<R> &operator=(const enumerator_iter<R> &Other) {
1196 Result = Other.Result;
1197 return *this;
1198 }
1199
1200private:
1201 result_type Result;
1202};
1203
1204template <typename R> class enumerator {
1205public:
1206 explicit enumerator(R &&Range) : TheRange(std::forward<R>(Range)) {}
1207
1208 enumerator_iter<R> begin() {
1209 return enumerator_iter<R>(0, std::begin(TheRange));
1210 }
1211
1212 enumerator_iter<R> end() {
1213 return enumerator_iter<R>(std::end(TheRange));
1214 }
1215
1216private:
1217 R TheRange;
1218};
1219
1220} // end namespace detail
1221
1222/// Given an input range, returns a new range whose values are are pair (A,B)
1223/// such that A is the 0-based index of the item in the sequence, and B is
1224/// the value from the original sequence. Example:
1225///
1226/// std::vector<char> Items = {'A', 'B', 'C', 'D'};
1227/// for (auto X : enumerate(Items)) {
1228/// printf("Item %d - %c\n", X.index(), X.value());
1229/// }
1230///
1231/// Output:
1232/// Item 0 - A
1233/// Item 1 - B
1234/// Item 2 - C
1235/// Item 3 - D
1236///
1237template <typename R> detail::enumerator<R> enumerate(R &&TheRange) {
1238 return detail::enumerator<R>(std::forward<R>(TheRange));
1239}
1240
1241namespace detail {
1242
1243template <typename F, typename Tuple, std::size_t... I>
1244auto apply_tuple_impl(F &&f, Tuple &&t, index_sequence<I...>)
1245 -> decltype(std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...)) {
1246 return std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...);
1247}
1248
1249} // end namespace detail
1250
1251/// Given an input tuple (a1, a2, ..., an), pass the arguments of the
1252/// tuple variadically to f as if by calling f(a1, a2, ..., an) and
1253/// return the result.
1254template <typename F, typename Tuple>
1255auto apply_tuple(F &&f, Tuple &&t) -> decltype(detail::apply_tuple_impl(
1256 std::forward<F>(f), std::forward<Tuple>(t),
1257 build_index_impl<
1258 std::tuple_size<typename std::decay<Tuple>::type>::value>{})) {
1259 using Indices = build_index_impl<
1260 std::tuple_size<typename std::decay<Tuple>::type>::value>;
1261
1262 return detail::apply_tuple_impl(std::forward<F>(f), std::forward<Tuple>(t),
1263 Indices{});
1264}
1265
1266} // end namespace llvm
1267
1268#endif // LLVM_ADT_STLEXTRAS_H
1269

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