#include "llvm/ADT/iterator.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
namespace llvm {
std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
}
+/// Iterator wrapper that concatenates sequences together.
+///
+/// This can concatenate different iterators, even with different types, into
+/// a single iterator provided the value types of all the concatenated
+/// iterators expose `reference` and `pointer` types that can be converted to
+/// `ValueT &` and `ValueT *` respectively. It doesn't support more
+/// interesting/customized pointer or reference types.
+///
+/// Currently this only supports forward or higher iterator categories as
+/// inputs and always exposes a forward iterator interface.
+template <typename ValueT, typename... IterTs>
+class concat_iterator
+ : public iterator_facade_base<concat_iterator<ValueT, IterTs...>,
+ std::forward_iterator_tag, ValueT> {
+ typedef typename concat_iterator::iterator_facade_base BaseT;
+
+ /// We store both the current and end iterators for each concatenated
+ /// sequence in a tuple of pairs.
+ ///
+ /// Note that something like iterator_range seems nice at first here, but the
+ /// range properties are of little benefit and end up getting in the way
+ /// because we need to do mutation on the current iterators.
+ std::tuple<std::pair<IterTs, IterTs>...> IterPairs;
+
+ /// Attempts to increment a specific iterator.
+ ///
+ /// Returns true if it was able to increment the iterator. Returns false if
+ /// the iterator is already at the end iterator.
+ template <size_t Index> bool incrementHelper() {
+ auto &IterPair = std::get<Index>(IterPairs);
+ if (IterPair.first == IterPair.second)
+ return false;
+
+ ++IterPair.first;
+ return true;
+ }
+
+ /// Increments the first non-end iterator.
+ ///
+ /// It is an error to call this with all iterators at the end.
+ template <size_t... Ns> void increment(index_sequence<Ns...>) {
+ // Build a sequence of functions to increment each iterator if possible.
+ bool (concat_iterator::*IncrementHelperFns[])() = {
+ &concat_iterator::incrementHelper<Ns>...};
+
+ // Loop over them, and stop as soon as we succeed at incrementing one.
+ for (auto &IncrementHelperFn : IncrementHelperFns)
+ if ((this->*IncrementHelperFn)())
+ return;
+
+ llvm_unreachable("Attempted to increment an end concat iterator!");
+ }
+
+ /// Returns null if the specified iterator is at the end. Otherwise,
+ /// dereferences the iterator and returns the address of the resulting
+ /// reference.
+ template <size_t Index> ValueT *getHelper() const {
+ auto &IterPair = std::get<Index>(IterPairs);
+ if (IterPair.first == IterPair.second)
+ return nullptr;
+
+ return &*IterPair.first;
+ }
+
+ /// Finds the first non-end iterator, dereferences, and returns the resulting
+ /// reference.
+ ///
+ /// It is an error to call this with all iterators at the end.
+ template <size_t... Ns> ValueT &get(index_sequence<Ns...>) const {
+ // Build a sequence of functions to get from iterator if possible.
+ ValueT *(concat_iterator::*GetHelperFns[])() const = {
+ &concat_iterator::getHelper<Ns>...};
+
+ // Loop over them, and return the first result we find.
+ for (auto &GetHelperFn : GetHelperFns)
+ if (ValueT *P = (this->*GetHelperFn)())
+ return *P;
+
+ llvm_unreachable("Attempted to get a pointer from an end concat iterator!");
+ }
+
+public:
+ /// Constructs an iterator from a squence of ranges.
+ ///
+ /// We need the full range to know how to switch between each of the
+ /// iterators.
+ template <typename... RangeTs>
+ explicit concat_iterator(RangeTs &&... Ranges)
+ : IterPairs({std::begin(Ranges), std::end(Ranges)}...) {}
+
+ using BaseT::operator++;
+ concat_iterator &operator++() {
+ increment(index_sequence_for<IterTs...>());
+ return *this;
+ }
+
+ ValueT &operator*() const { return get(index_sequence_for<IterTs...>()); }
+
+ bool operator==(const concat_iterator &RHS) const {
+ return IterPairs == RHS.IterPairs;
+ }
+};
+
+namespace detail {
+/// Helper to store a sequence of ranges being concatenated and access them.
+///
+/// This is designed to facilitate providing actual storage when temporaries
+/// are passed into the constructor such that we can use it as part of range
+/// based for loops.
+template <typename ValueT, typename... RangeTs> class concat_range {
+public:
+ typedef concat_iterator<ValueT,
+ decltype(std::begin(std::declval<RangeTs &>()))...>
+ iterator;
+
+private:
+ std::tuple<RangeTs...> Ranges;
+
+ template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) {
+ return iterator(std::get<Ns>(Ranges)...);
+ }
+ template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) {
+ return iterator(make_range(std::end(std::get<Ns>(Ranges)),
+ std::end(std::get<Ns>(Ranges)))...);
+ }
+
+public:
+ iterator begin() { return begin_impl(index_sequence_for<RangeTs...>{}); }
+ iterator end() { return end_impl(index_sequence_for<RangeTs...>{}); }
+ concat_range(RangeTs &&... Ranges)
+ : Ranges(std::forward<RangeTs>(Ranges)...) {}
+};
+}
+
+/// Concatenated range across two or more ranges.
+///
+/// The desired value type must be explicitly specified.
+template <typename ValueT, typename... RangeTs>
+detail::concat_range<ValueT, RangeTs...> concat(RangeTs &&... Ranges) {
+ static_assert(sizeof...(RangeTs) > 1,
+ "Need more than one range to concatenate!");
+ return detail::concat_range<ValueT, RangeTs...>(
+ std::forward<RangeTs>(Ranges)...);
+}
+
//===----------------------------------------------------------------------===//
// Extra additions to <utility>
//===----------------------------------------------------------------------===//
/// @name Convenience iterators
/// @{
- template <bool IsConst> class global_object_iterator_t {
- friend Module;
-
- typename std::conditional<IsConst, const_iterator, iterator>::type
- function_i,
- function_e;
- typename std::conditional<IsConst, const_global_iterator,
- global_iterator>::type global_i;
-
- typedef
- typename std::conditional<IsConst, const Module, Module>::type ModuleTy;
-
- global_object_iterator_t(ModuleTy &M)
- : function_i(M.begin()), function_e(M.end()),
- global_i(M.global_begin()) {}
- global_object_iterator_t(ModuleTy &M, int)
- : function_i(M.end()), function_e(M.end()), global_i(M.global_end()) {}
-
- public:
- global_object_iterator_t &operator++() {
- if (function_i != function_e)
- ++function_i;
- else
- ++global_i;
- return *this;
- }
-
- typename std::conditional<IsConst, const GlobalObject, GlobalObject>::type &
- operator*() const {
- if (function_i != function_e)
- return *function_i;
- else
- return *global_i;
- }
-
- bool operator!=(const global_object_iterator_t &other) const {
- return function_i != other.function_i || global_i != other.global_i;
- }
- };
-
- typedef global_object_iterator_t</*IsConst=*/false> global_object_iterator;
- typedef global_object_iterator_t</*IsConst=*/true>
+ typedef concat_iterator<GlobalObject, iterator, global_iterator>
+ global_object_iterator;
+ typedef concat_iterator<const GlobalObject, const_iterator,
+ const_global_iterator>
const_global_object_iterator;
- global_object_iterator global_object_begin() {
- return global_object_iterator(*this);
+ iterator_range<global_object_iterator> global_objects() {
+ return concat<GlobalObject>(functions(), globals());
}
- global_object_iterator global_object_end() {
- return global_object_iterator(*this, 0);
+ iterator_range<const_global_object_iterator> global_objects() const {
+ return concat<const GlobalObject>(functions(), globals());
}
- const_global_object_iterator global_object_begin() const {
- return const_global_object_iterator(*this);
- }
- const_global_object_iterator global_object_end() const {
- return const_global_object_iterator(*this, 0);
+ global_object_iterator global_object_begin() {
+ return global_objects().begin();
}
+ global_object_iterator global_object_end() { return global_objects().end(); }
- iterator_range<global_object_iterator> global_objects() {
- return make_range(global_object_begin(), global_object_end());
+ const_global_object_iterator global_object_begin() const {
+ return global_objects().begin();
}
- iterator_range<const_global_object_iterator> global_objects() const {
- return make_range(global_object_begin(), global_object_end());
+ const_global_object_iterator global_object_end() const {
+ return global_objects().end();
}
/// @}
#include "llvm/ADT/STLExtras.h"
#include "gtest/gtest.h"
+#include <list>
#include <vector>
using namespace llvm;
EXPECT_EQ(1, count(v, 3));
EXPECT_EQ(1, count(v, 4));
}
+
+TEST(STLExtrasTest, ConcatRange) {
+ std::vector<int> Expected = {1, 2, 3, 4, 5, 6, 7, 8};
+ std::vector<int> Test;
+
+ std::vector<int> V1234 = {1, 2, 3, 4};
+ std::list<int> L56 = {5, 6};
+ SmallVector<int, 2> SV78 = {7, 8};
+
+ // Use concat across different sized ranges of different types with different
+ // iterators.
+ for (int &i : concat<int>(V1234, L56, SV78))
+ Test.push_back(i);
+ EXPECT_EQ(Expected, Test);
+
+ // Use concat between a temporary, an L-value, and an R-value to make sure
+ // complex lifetimes work well.
+ Test.clear();
+ for (int &i : concat<int>(std::vector<int>(V1234), L56, std::move(SV78)))
+ Test.push_back(i);
+ EXPECT_EQ(Expected, Test);
+}
}
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