1 //===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains some templates that are useful if you are working with the
13 // No library is required when using these functions.
15 //===----------------------------------------------------------------------===//
17 #ifndef LLVM_ADT_STLEXTRAS_H
18 #define LLVM_ADT_STLEXTRAS_H
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"
31 #include <initializer_list>
36 #include <type_traits>
39 #ifdef EXPENSIVE_CHECKS
40 #include <random> // for std::mt19937
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.
47 template <typename T, T> struct SameType;
51 template <typename RangeT>
52 using IterOfRange = decltype(std::begin(std::declval<RangeT &>()));
54 template <typename RangeT>
55 using ValueOfRange = typename std::remove_reference<decltype(
56 *std::begin(std::declval<RangeT &>()))>::type;
58 } // end namespace detail
60 //===----------------------------------------------------------------------===//
61 // Extra additions to <type_traits>
62 //===----------------------------------------------------------------------===//
65 struct negation : std::integral_constant<bool, !bool(T::value)> {};
67 template <typename...> struct conjunction : std::true_type {};
68 template <typename B1> struct conjunction<B1> : B1 {};
69 template <typename B1, typename... Bn>
70 struct conjunction<B1, Bn...>
71 : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};
73 //===----------------------------------------------------------------------===//
74 // Extra additions to <functional>
75 //===----------------------------------------------------------------------===//
77 template <class Ty> struct identity {
78 using argument_type = Ty;
80 Ty &operator()(Ty &self) const {
83 const Ty &operator()(const Ty &self) const {
88 template <class Ty> struct less_ptr {
89 bool operator()(const Ty* left, const Ty* right) const {
90 return *left < *right;
94 template <class Ty> struct greater_ptr {
95 bool operator()(const Ty* left, const Ty* right) const {
96 return *right < *left;
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.
104 /// This class does not own the callable, so it is not in general safe to store
106 template<typename Fn> class function_ref;
108 template<typename Ret, typename ...Params>
109 class function_ref<Ret(Params...)> {
110 Ret (*callback)(intptr_t callable, Params ...params) = nullptr;
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)...);
120 function_ref() = default;
121 function_ref(std::nullptr_t) {}
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)) {}
131 Ret operator()(Params ...params) const {
132 return callback(callable, std::forward<Params>(params)...);
135 operator bool() const { return callback; }
138 // deleter - Very very very simple method that is used to invoke operator
139 // delete on something. It is used like this:
141 // for_each(V.begin(), B.end(), deleter<Interval>);
143 inline void deleter(T *Ptr) {
147 //===----------------------------------------------------------------------===//
148 // Extra additions to <iterator>
149 //===----------------------------------------------------------------------===//
151 namespace adl_detail {
155 template <typename ContainerTy>
156 auto adl_begin(ContainerTy &&container)
157 -> decltype(begin(std::forward<ContainerTy>(container))) {
158 return begin(std::forward<ContainerTy>(container));
163 template <typename ContainerTy>
164 auto adl_end(ContainerTy &&container)
165 -> decltype(end(std::forward<ContainerTy>(container))) {
166 return end(std::forward<ContainerTy>(container));
171 template <typename T>
172 void 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));
177 } // end namespace adl_detail
179 template <typename ContainerTy>
180 auto adl_begin(ContainerTy &&container)
181 -> decltype(adl_detail::adl_begin(std::forward<ContainerTy>(container))) {
182 return adl_detail::adl_begin(std::forward<ContainerTy>(container));
185 template <typename ContainerTy>
186 auto adl_end(ContainerTy &&container)
187 -> decltype(adl_detail::adl_end(std::forward<ContainerTy>(container))) {
188 return adl_detail::adl_end(std::forward<ContainerTy>(container));
191 template <typename T>
192 void 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));
197 // mapped_iterator - This is a simple iterator adapter that causes a function to
198 // be applied whenever operator* is invoked on the iterator.
200 template <typename ItTy, typename FuncTy,
201 typename FuncReturnTy =
202 decltype(std::declval<FuncTy>()(*std::declval<ItTy>()))>
203 class 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> {
209 mapped_iterator(ItTy U, FuncTy F)
210 : mapped_iterator::iterator_adaptor_base(std::move(U)), F(std::move(F)) {}
212 ItTy getCurrent() { return this->I; }
214 FuncReturnTy operator*() { return F(*this->I); }
220 // map_iterator - Provide a convenient way to create mapped_iterators, just like
221 // make_pair is useful for creating pairs...
222 template <class ItTy, class FuncTy>
223 inline mapped_iterator<ItTy, FuncTy> map_iterator(ItTy I, FuncTy F) {
224 return mapped_iterator<ItTy, FuncTy>(std::move(I), std::move(F));
227 /// Helper to determine if type T has a member called rbegin().
228 template <typename Ty> class has_rbegin_impl {
232 template <typename Inner>
233 static yes& test(Inner *I, decltype(I->rbegin()) * = nullptr);
236 static no& test(...);
239 static const bool value = sizeof(test<Ty>(nullptr)) == sizeof(yes);
242 /// Metafunction to determine if T& or T has a member called rbegin().
243 template <typename Ty>
244 struct has_rbegin : has_rbegin_impl<typename std::remove_reference<Ty>::type> {
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.
249 template <typename ContainerTy>
250 auto 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());
256 // Returns a std::reverse_iterator wrapped around the given iterator.
257 template <typename IteratorTy>
258 std::reverse_iterator<IteratorTy> make_reverse_iterator(IteratorTy It) {
259 return std::reverse_iterator<IteratorTy>(It);
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.
265 template <typename ContainerTy>
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)));
275 /// An iterator adaptor that filters the elements of given inner iterators.
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.
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 }.
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.
291 template <typename WrappedIteratorT, typename PredicateT, typename IterTag>
292 class filter_iterator_base
293 : public iterator_adaptor_base<
294 filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>,
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>,
302 typename std::common_type<
303 IterTag, typename std::iterator_traits<
304 WrappedIteratorT>::iterator_category>::type>;
307 WrappedIteratorT End;
310 void findNextValid() {
311 while (this->I != End && !Pred(*this->I))
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,
320 : BaseT(Begin), End(End), Pred(Pred) {
325 using BaseT::operator++;
327 filter_iterator_base &operator++() {
334 /// Specialization of filter_iterator_base for forward iteration only.
335 template <typename WrappedIteratorT, typename PredicateT,
336 typename IterTag = std::forward_iterator_tag>
337 class filter_iterator_impl
338 : public filter_iterator_base<WrappedIteratorT, PredicateT, IterTag> {
339 using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>;
342 filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
344 : BaseT(Begin, End, Pred) {}
347 /// Specialization of filter_iterator_base for bidirectional iteration.
348 template <typename WrappedIteratorT, typename PredicateT>
349 class 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))
361 using BaseT::operator--;
363 filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
365 : BaseT(Begin, End, Pred) {}
367 filter_iterator_impl &operator--() {
376 template <bool is_bidirectional> struct fwd_or_bidi_tag_impl {
377 using type = std::forward_iterator_tag;
380 template <> struct fwd_or_bidi_tag_impl<true> {
381 using type = std::bidirectional_iterator_tag;
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.
387 template <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;
393 } // namespace detail
395 /// Defines filter_iterator to a suitable specialization of
396 /// filter_iterator_impl, based on the underlying iterator's category.
397 template <typename WrappedIteratorT, typename PredicateT>
398 using filter_iterator = filter_iterator_impl<
399 WrappedIteratorT, PredicateT,
400 typename detail::fwd_or_bidi_tag<WrappedIteratorT>::type>;
402 /// Convenience function that takes a range of elements and a predicate,
403 /// and return a new filter_iterator range.
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.
409 template <typename RangeT, typename PredicateT>
410 iterator_range<filter_iterator<detail::IterOfRange<RangeT>, PredicateT>>
411 make_filter_range(RangeT &&Range, PredicateT Pred) {
412 using FilterIteratorT =
413 filter_iterator<detail::IterOfRange<RangeT>, PredicateT>;
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));
421 // forward declarations required by zip_shortest/zip_first
422 template <typename R, typename UnaryPredicate>
423 bool all_of(R &&range, UnaryPredicate P);
425 template <size_t... I> struct index_sequence;
427 template <class... Ts> struct index_sequence_for;
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.
435 template<typename... Iters> struct ZipTupleType {
436 using type = std::tuple<decltype(*declval<Iters>())...>;
439 template <typename ZipType, typename... Iters>
440 using 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
452 typename ZipTupleType<Iters...>::type *,
453 typename ZipTupleType<Iters...>::type>;
455 template <typename ZipType, typename... Iters>
456 struct zip_common : public zip_traits<ZipType, Iters...> {
457 using Base = zip_traits<ZipType, Iters...>;
458 using value_type = typename Base::value_type;
460 std::tuple<Iters...> iterators;
463 template <size_t... Ns> value_type deref(index_sequence<Ns...>) const {
464 return value_type(*std::get<Ns>(iterators)...);
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))...);
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))...);
478 zip_common(Iters &&... ts) : iterators(std::forward<Iters>(ts)...) {}
480 value_type operator*() { return deref(index_sequence_for<Iters...>{}); }
482 const value_type operator*() const {
483 return deref(index_sequence_for<Iters...>{});
486 ZipType &operator++() {
487 iterators = tup_inc(index_sequence_for<Iters...>{});
488 return *reinterpret_cast<ZipType *>(this);
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);
499 template <typename... Iters>
500 struct zip_first : public zip_common<zip_first<Iters...>, Iters...> {
501 using Base = zip_common<zip_first<Iters...>, Iters...>;
503 bool operator==(const zip_first<Iters...> &other) const {
504 return std::get<0>(this->iterators) == std::get<0>(other.iterators);
507 zip_first(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
510 template <typename... Iters>
511 class 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)...},
520 using Base = zip_common<zip_shortest<Iters...>, Iters...>;
522 zip_shortest(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
524 bool operator==(const zip_shortest<Iters...> &other) const {
525 return !test(other, index_sequence_for<Iters...>{});
529 template <template <typename...> class ItType, typename... Args> class zippy {
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;
539 std::tuple<Args...> ts;
541 template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) const {
542 return iterator(std::begin(std::get<Ns>(ts))...);
544 template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) const {
545 return iterator(std::end(std::get<Ns>(ts))...);
549 zippy(Args &&... ts_) : ts(std::forward<Args>(ts_)...) {}
551 iterator begin() const { return begin_impl(index_sequence_for<Args...>{}); }
552 iterator end() const { return end_impl(index_sequence_for<Args...>{}); }
555 } // end namespace detail
557 /// zip iterator for two or more iteratable types.
558 template <typename T, typename U, typename... Args>
559 detail::zippy<detail::zip_shortest, T, U, Args...> zip(T &&t, U &&u,
561 return detail::zippy<detail::zip_shortest, T, U, Args...>(
562 std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
565 /// zip iterator that, for the sake of efficiency, assumes the first iteratee to
567 template <typename T, typename U, typename... Args>
568 detail::zippy<detail::zip_first, T, U, Args...> zip_first(T &&t, U &&u,
570 return detail::zippy<detail::zip_first, T, U, Args...>(
571 std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
574 /// Iterator wrapper that concatenates sequences together.
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.
582 /// Currently this only supports forward or higher iterator categories as
583 /// inputs and always exposes a forward iterator interface.
584 template <typename ValueT, typename... IterTs>
585 class 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;
590 /// We store both the current and end iterators for each concatenated
591 /// sequence in a tuple of pairs.
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;
598 /// Attempts to increment a specific iterator.
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)
611 /// Increments the first non-end iterator.
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>...};
619 // Loop over them, and stop as soon as we succeed at incrementing one.
620 for (auto &IncrementHelperFn : IncrementHelperFns)
621 if ((this->*IncrementHelperFn)())
624 llvm_unreachable("Attempted to increment an end concat iterator!");
627 /// Returns null if the specified iterator is at the end. Otherwise,
628 /// dereferences the iterator and returns the address of the resulting
630 template <size_t Index> ValueT *getHelper() const {
631 auto &IterPair = std::get<Index>(IterPairs);
632 if (IterPair.first == IterPair.second)
635 return &*IterPair.first;
638 /// Finds the first non-end iterator, dereferences, and returns the resulting
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>...};
647 // Loop over them, and return the first result we find.
648 for (auto &GetHelperFn : GetHelperFns)
649 if (ValueT *P = (this->*GetHelperFn)())
652 llvm_unreachable("Attempted to get a pointer from an end concat iterator!");
656 /// Constructs an iterator from a squence of ranges.
658 /// We need the full range to know how to switch between each of the
660 template <typename... RangeTs>
661 explicit concat_iterator(RangeTs &&... Ranges)
662 : IterPairs({std::begin(Ranges), std::end(Ranges)}...) {}
664 using BaseT::operator++;
666 concat_iterator &operator++() {
667 increment(index_sequence_for<IterTs...>());
671 ValueT &operator*() const { return get(index_sequence_for<IterTs...>()); }
673 bool operator==(const concat_iterator &RHS) const {
674 return IterPairs == RHS.IterPairs;
680 /// Helper to store a sequence of ranges being concatenated and access them.
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
685 template <typename ValueT, typename... RangeTs> class concat_range {
688 concat_iterator<ValueT,
689 decltype(std::begin(std::declval<RangeTs &>()))...>;
692 std::tuple<RangeTs...> Ranges;
694 template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) {
695 return iterator(std::get<Ns>(Ranges)...);
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)))...);
703 concat_range(RangeTs &&... Ranges)
704 : Ranges(std::forward<RangeTs>(Ranges)...) {}
706 iterator begin() { return begin_impl(index_sequence_for<RangeTs...>{}); }
707 iterator end() { return end_impl(index_sequence_for<RangeTs...>{}); }
710 } // end namespace detail
712 /// Concatenated range across two or more ranges.
714 /// The desired value type must be explicitly specified.
715 template <typename ValueT, typename... RangeTs>
716 detail::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)...);
723 //===----------------------------------------------------------------------===//
724 // Extra additions to <utility>
725 //===----------------------------------------------------------------------===//
727 /// Function object to check whether the first component of a std::pair
728 /// compares less than the first component of another std::pair.
730 template <typename T> bool operator()(const T &lhs, const T &rhs) const {
731 return lhs.first < rhs.first;
735 /// Function object to check whether the second component of a std::pair
736 /// compares less than the second component of another std::pair.
738 template <typename T> bool operator()(const T &lhs, const T &rhs) const {
739 return lhs.second < rhs.second;
743 // A subset of N3658. More stuff can be added as-needed.
745 /// Represents a compile-time sequence of integers.
746 template <class T, T... I> struct integer_sequence {
747 using value_type = T;
749 static constexpr size_t size() { return sizeof...(I); }
752 /// Alias for the common case of a sequence of size_ts.
753 template <size_t... I>
754 struct index_sequence : integer_sequence<std::size_t, I...> {};
756 template <std::size_t N, std::size_t... I>
757 struct build_index_impl : build_index_impl<N - 1, N - 1, I...> {};
758 template <std::size_t... I>
759 struct build_index_impl<0, I...> : index_sequence<I...> {};
761 /// Creates a compile-time integer sequence for a parameter pack.
762 template <class... Ts>
763 struct index_sequence_for : build_index_impl<sizeof...(Ts)> {};
765 /// Utility type to build an inheritance chain that makes it easy to rank
766 /// overload candidates.
767 template <int N> struct rank : rank<N - 1> {};
768 template <> struct rank<0> {};
770 /// traits class for checking whether type T is one of any of the given
771 /// types in the variadic list.
772 template <typename T, typename... Ts> struct is_one_of {
773 static const bool value = false;
776 template <typename T, typename U, typename... Ts>
777 struct is_one_of<T, U, Ts...> {
778 static const bool value =
779 std::is_same<T, U>::value || is_one_of<T, Ts...>::value;
782 /// traits class for checking whether type T is a base class for all
783 /// the given types in the variadic list.
784 template <typename T, typename... Ts> struct are_base_of {
785 static const bool value = true;
788 template <typename T, typename U, typename... Ts>
789 struct 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;
794 //===----------------------------------------------------------------------===//
795 // Extra additions for arrays
796 //===----------------------------------------------------------------------===//
798 /// Find the length of an array.
799 template <class T, std::size_t N>
800 constexpr inline size_t array_lengthof(T (&)[N]) {
804 /// Adapt std::less<T> for array_pod_sort.
806 inline 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)))
810 if (std::less<T>()(*reinterpret_cast<const T*>(P2),
811 *reinterpret_cast<const T*>(P1)))
816 /// get_array_pod_sort_comparator - This is an internal helper function used to
817 /// get type deduction of T right.
819 inline int (*get_array_pod_sort_comparator(const T &))
820 (const void*, const void*) {
821 return array_pod_sort_comparator<T>;
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
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.
836 /// NOTE: If qsort_r were portable, we could allow a custom comparator and
837 /// default to std::less.
838 template<class IteratorTy>
839 inline 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);
848 qsort(&*Start, NElts, sizeof(*Start), get_array_pod_sort_comparator(*Start));
851 template <class IteratorTy>
852 inline void array_pod_sort(
853 IteratorTy Start, IteratorTy End,
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);
865 qsort(&*Start, NElts, sizeof(*Start),
866 reinterpret_cast<int (*)(const void *, const void *)>(Compare));
869 // Provide wrappers to std::sort which shuffle the elements before sorting
870 // to help uncover non-deterministic behavior (PR35135).
871 template <typename IteratorTy>
872 inline void sort(IteratorTy Start, IteratorTy End) {
873 #ifdef EXPENSIVE_CHECKS
874 std::mt19937 Generator(std::random_device{}());
875 std::shuffle(Start, End, Generator);
877 std::sort(Start, End);
880 template <typename IteratorTy, typename Compare>
881 inline 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);
886 std::sort(Start, End, Comp);
889 //===----------------------------------------------------------------------===//
890 // Extra additions to <algorithm>
891 //===----------------------------------------------------------------------===//
893 /// For a container of pointers, deletes the pointers and then clears the
895 template<typename Container>
896 void DeleteContainerPointers(Container &C) {
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.
904 template<typename Container>
905 void DeleteContainerSeconds(Container &C) {
911 /// Provide wrappers to std::for_each which take ranges instead of having to
912 /// pass begin/end explicitly.
913 template <typename R, typename UnaryPredicate>
914 UnaryPredicate for_each(R &&Range, UnaryPredicate P) {
915 return std::for_each(adl_begin(Range), adl_end(Range), P);
918 /// Provide wrappers to std::all_of which take ranges instead of having to pass
919 /// begin/end explicitly.
920 template <typename R, typename UnaryPredicate>
921 bool all_of(R &&Range, UnaryPredicate P) {
922 return std::all_of(adl_begin(Range), adl_end(Range), P);
925 /// Provide wrappers to std::any_of which take ranges instead of having to pass
926 /// begin/end explicitly.
927 template <typename R, typename UnaryPredicate>
928 bool any_of(R &&Range, UnaryPredicate P) {
929 return std::any_of(adl_begin(Range), adl_end(Range), P);
932 /// Provide wrappers to std::none_of which take ranges instead of having to pass
933 /// begin/end explicitly.
934 template <typename R, typename UnaryPredicate>
935 bool none_of(R &&Range, UnaryPredicate P) {
936 return std::none_of(adl_begin(Range), adl_end(Range), P);
939 /// Provide wrappers to std::find which take ranges instead of having to pass
940 /// begin/end explicitly.
941 template <typename R, typename T>
942 auto find(R &&Range, const T &Val) -> decltype(adl_begin(Range)) {
943 return std::find(adl_begin(Range), adl_end(Range), Val);
946 /// Provide wrappers to std::find_if which take ranges instead of having to pass
947 /// begin/end explicitly.
948 template <typename R, typename UnaryPredicate>
949 auto find_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
950 return std::find_if(adl_begin(Range), adl_end(Range), P);
953 template <typename R, typename UnaryPredicate>
954 auto find_if_not(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
955 return std::find_if_not(adl_begin(Range), adl_end(Range), P);
958 /// Provide wrappers to std::remove_if which take ranges instead of having to
959 /// pass begin/end explicitly.
960 template <typename R, typename UnaryPredicate>
961 auto remove_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
962 return std::remove_if(adl_begin(Range), adl_end(Range), P);
965 /// Provide wrappers to std::copy_if which take ranges instead of having to
966 /// pass begin/end explicitly.
967 template <typename R, typename OutputIt, typename UnaryPredicate>
968 OutputIt copy_if(R &&Range, OutputIt Out, UnaryPredicate P) {
969 return std::copy_if(adl_begin(Range), adl_end(Range), Out, P);
972 template <typename R, typename OutputIt>
973 OutputIt copy(R &&Range, OutputIt Out) {
974 return std::copy(adl_begin(Range), adl_end(Range), Out);
977 /// Wrapper function around std::find to detect if an element exists
979 template <typename R, typename E>
980 bool is_contained(R &&Range, const E &Element) {
981 return std::find(adl_begin(Range), adl_end(Range), Element) != adl_end(Range);
984 /// Wrapper function around std::count to count the number of times an element
985 /// \p Element occurs in the given range \p Range.
986 template <typename R, typename E>
987 auto 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);
992 /// Wrapper function around std::count_if to count the number of times an
993 /// element satisfying a given predicate occurs in a range.
994 template <typename R, typename UnaryPredicate>
995 auto 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);
1000 /// Wrapper function around std::transform to apply a function to a range and
1001 /// store the result elsewhere.
1002 template <typename R, typename OutputIt, typename UnaryPredicate>
1003 OutputIt transform(R &&Range, OutputIt d_first, UnaryPredicate P) {
1004 return std::transform(adl_begin(Range), adl_end(Range), d_first, P);
1007 /// Provide wrappers to std::partition which take ranges instead of having to
1008 /// pass begin/end explicitly.
1009 template <typename R, typename UnaryPredicate>
1010 auto partition(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1011 return std::partition(adl_begin(Range), adl_end(Range), P);
1014 /// Provide wrappers to std::lower_bound which take ranges instead of having to
1015 /// pass begin/end explicitly.
1016 template <typename R, typename ForwardIt>
1017 auto lower_bound(R &&Range, ForwardIt I) -> decltype(adl_begin(Range)) {
1018 return std::lower_bound(adl_begin(Range), adl_end(Range), I);
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.
1024 template <unsigned Size, typename R>
1025 SmallVector<typename std::remove_const<detail::ValueOfRange<R>>::type, Size>
1026 to_vector(R &&Range) {
1027 return {adl_begin(Range), adl_end(Range)};
1030 /// Provide a container algorithm similar to C++ Library Fundamentals v2's
1031 /// `erase_if` which is equivalent to:
1033 /// C.erase(remove_if(C, pred), C.end());
1035 /// This version works for any container with an erase method call accepting
1037 template <typename Container, typename UnaryPredicate>
1038 void erase_if(Container &C, UnaryPredicate P) {
1039 C.erase(remove_if(C, P), C.end());
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).
1044 template <typename R>
1045 auto 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());
1054 //===----------------------------------------------------------------------===//
1055 // Extra additions to <memory>
1056 //===----------------------------------------------------------------------===//
1058 // Implement make_unique according to N3656.
1060 /// Constructs a `new T()` with the given args and returns a
1061 /// `unique_ptr<T>` which owns the object.
1065 /// auto p = make_unique<int>();
1066 /// auto p = make_unique<std::tuple<int, int>>(0, 1);
1067 template <class T, class... Args>
1068 typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
1069 make_unique(Args &&... args) {
1070 return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
1073 /// Constructs a `new T[n]` with the given args and returns a
1074 /// `unique_ptr<T[]>` which owns the object.
1076 /// \param n size of the new array.
1080 /// auto p = make_unique<int[]>(2); // value-initializes the array with 0's.
1082 typename std::enable_if<std::is_array<T>::value && std::extent<T>::value == 0,
1083 std::unique_ptr<T>>::type
1084 make_unique(size_t n) {
1085 return std::unique_ptr<T>(new typename std::remove_extent<T>::type[n]());
1088 /// This function isn't used and is only here to provide better compile errors.
1089 template <class T, class... Args>
1090 typename std::enable_if<std::extent<T>::value != 0>::type
1091 make_unique(Args &&...) = delete;
1093 struct FreeDeleter {
1094 void operator()(void* v) {
1099 template<typename First, typename Second>
1101 size_t operator()(const std::pair<First, Second> &P) const {
1102 return std::hash<First>()(P.first) * 31 + std::hash<Second>()(P.second);
1106 /// A functor like C++14's std::less<void> in its absence.
1108 template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1109 return std::forward<A>(a) < std::forward<B>(b);
1113 /// A functor like C++14's std::equal<void> in its absence.
1115 template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1116 return std::forward<A>(a) == std::forward<B>(b);
1120 /// Binary functor that adapts to any other binary functor after dereferencing
1122 template <typename T> struct deref {
1125 // Could be further improved to cope with non-derivable functors and
1126 // non-binary functors (should be a variadic template member function
1128 template <typename A, typename B>
1129 auto operator()(A &lhs, B &rhs) const -> decltype(func(*lhs, *rhs)) {
1132 return func(*lhs, *rhs);
1138 template <typename R> class enumerator_iter;
1140 template <typename R> struct result_pair {
1141 friend class enumerator_iter<R>;
1143 result_pair() = default;
1144 result_pair(std::size_t Index, IterOfRange<R> Iter)
1145 : Index(Index), Iter(Iter) {}
1147 result_pair<R> &operator=(const result_pair<R> &Other) {
1148 Index = Other.Index;
1153 std::size_t index() const { return Index; }
1154 const ValueOfRange<R> &value() const { return *Iter; }
1155 ValueOfRange<R> &value() { return *Iter; }
1158 std::size_t Index = std::numeric_limits<std::size_t>::max();
1159 IterOfRange<R> Iter;
1162 template <typename R>
1163 class 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>;
1172 explicit enumerator_iter(IterOfRange<R> EndIter)
1173 : Result(std::numeric_limits<size_t>::max(), EndIter) {}
1175 enumerator_iter(std::size_t Index, IterOfRange<R> Iter)
1176 : Result(Index, Iter) {}
1178 result_type &operator*() { return Result; }
1179 const result_type &operator*() const { return Result; }
1181 enumerator_iter<R> &operator++() {
1182 assert(Result.Index != std::numeric_limits<size_t>::max());
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;
1195 enumerator_iter<R> &operator=(const enumerator_iter<R> &Other) {
1196 Result = Other.Result;
1204 template <typename R> class enumerator {
1206 explicit enumerator(R &&Range) : TheRange(std::forward<R>(Range)) {}
1208 enumerator_iter<R> begin() {
1209 return enumerator_iter<R>(0, std::begin(TheRange));
1212 enumerator_iter<R> end() {
1213 return enumerator_iter<R>(std::end(TheRange));
1220 } // end namespace detail
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:
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());
1237 template <typename R> detail::enumerator<R> enumerate(R &&TheRange) {
1238 return detail::enumerator<R>(std::forward<R>(TheRange));
1243 template <typename F, typename Tuple, std::size_t... I>
1244 auto 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))...);
1249 } // end namespace detail
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.
1254 template <typename F, typename Tuple>
1255 auto apply_tuple(F &&f, Tuple &&t) -> decltype(detail::apply_tuple_impl(
1256 std::forward<F>(f), std::forward<Tuple>(t),
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>;
1262 return detail::apply_tuple_impl(std::forward<F>(f), std::forward<Tuple>(t),
1266 } // end namespace llvm
1268 #endif // LLVM_ADT_STLEXTRAS_H