[libcxx] r243530 - Fix a self-move bug in inplace_merge. Thanks to Ted and Dexon for the report and the suggested fix.
Duncan P. N. Exon Smith
dexonsmith at apple.com
Thu Jul 30 16:33:31 PDT 2015
Hans, I think this fix should be merged into 3.7.
Marshall, do you agree?
> On 2015-Jul-29, at 09:25, Marshall Clow <mclow.lists at gmail.com> wrote:
>
> Author: marshall
> Date: Wed Jul 29 11:25:45 2015
> New Revision: 243530
>
> URL: http://llvm.org/viewvc/llvm-project?rev=243530&view=rev
> Log:
> Fix a self-move bug in inplace_merge. Thanks to Ted and Dexon for the report and the suggested fix.
>
> Modified:
> libcxx/trunk/include/algorithm
> libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge.pass.cpp
> libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge_comp.pass.cpp
>
> Modified: libcxx/trunk/include/algorithm
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/algorithm?rev=243530&r1=243529&r2=243530&view=diff
> ==============================================================================
> --- libcxx/trunk/include/algorithm (original)
> +++ libcxx/trunk/include/algorithm Wed Jul 29 11:25:45 2015
> @@ -4361,6 +4361,34 @@ merge(_InputIterator1 __first1, _InputIt
>
> // inplace_merge
>
> +template <class _Compare, class _InputIterator1, class _InputIterator2,
> + class _OutputIterator>
> +void __half_inplace_merge(_InputIterator1 __first1, _InputIterator1 __last1,
> + _InputIterator2 __first2, _InputIterator2 __last2,
> + _OutputIterator __result, _Compare __comp)
> +{
> + for (; __first1 != __last1; ++__result)
> + {
> + if (__first2 == __last2)
> + {
> + _VSTD::move(__first1, __last1, __result);
> + return;
> + }
> +
> + if (__comp(*__first2, *__first1))
> + {
> + *__result = _VSTD::move(*__first2);
> + ++__first2;
> + }
> + else
> + {
> + *__result = _VSTD::move(*__first1);
> + ++__first1;
> + }
> + }
> + // __first2 through __last2 are already in the right spot.
> +}
> +
> template <class _Compare, class _BidirectionalIterator>
> void
> __buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
> @@ -4376,11 +4404,7 @@ __buffered_inplace_merge(_BidirectionalI
> value_type* __p = __buff;
> for (_BidirectionalIterator __i = __first; __i != __middle; __d.__incr((value_type*)0), (void) ++__i, ++__p)
> ::new(__p) value_type(_VSTD::move(*__i));
> - __merge<_Compare>(move_iterator<value_type*>(__buff),
> - move_iterator<value_type*>(__p),
> - move_iterator<_BidirectionalIterator>(__middle),
> - move_iterator<_BidirectionalIterator>(__last),
> - __first, __comp);
> + __half_inplace_merge(__buff, __p, __middle, __last, __first, __comp);
> }
> else
> {
> @@ -4389,9 +4413,9 @@ __buffered_inplace_merge(_BidirectionalI
> ::new(__p) value_type(_VSTD::move(*__i));
> typedef reverse_iterator<_BidirectionalIterator> _RBi;
> typedef reverse_iterator<value_type*> _Rv;
> - __merge(move_iterator<_RBi>(_RBi(__middle)), move_iterator<_RBi>(_RBi(__first)),
> - move_iterator<_Rv>(_Rv(__p)), move_iterator<_Rv>(_Rv(__buff)),
> - _RBi(__last), __negate<_Compare>(__comp));
> + __half_inplace_merge(_Rv(__p), _Rv(__buff),
> + _RBi(__middle), _RBi(__first),
> + _RBi(__last), __negate<_Compare>(__comp));
> }
> }
>
>
> Modified: libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge.pass.cpp
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge.pass.cpp?rev=243530&r1=243529&r2=243530&view=diff
> ==============================================================================
> --- libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge.pass.cpp (original)
> +++ libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge.pass.cpp Wed Jul 29 11:25:45 2015
> @@ -20,12 +20,35 @@
>
> #include "test_iterators.h"
>
> +#ifndef TEST_STD_VER >= 11
> +struct S {
> + S() : i_(0) {}
> + S(int i) : i_(i) {}
> +
> + S(const S& rhs) : i_(rhs.i_) {}
> + S( S&& rhs) : i_(rhs.i_) { rhs.i_ = -1; }
> +
> + S& operator =(const S& rhs) { i_ = rhs.i_; return *this; }
> + S& operator =( S&& rhs) { i_ = rhs.i_; rhs.i_ = -2; assert(this != &rhs); return *this; }
> + S& operator =(int i) { i_ = i; return *this; }
> +
> + bool operator <(const S& rhs) const { return i_ < rhs.i_; }
> + bool operator ==(const S& rhs) const { return i_ == rhs.i_; }
> + bool operator ==(int i) const { return i_ == i; }
> +
> + void set(int i) { i_ = i; }
> +
> + int i_;
> + };
> +#endif
> +
> template <class Iter>
> void
> test_one(unsigned N, unsigned M)
> {
> + typedef typename std::iterator_traits<Iter>::value_type value_type;
> assert(M <= N);
> - int* ia = new int[N];
> + value_type* ia = new value_type[N];
> for (unsigned i = 0; i < N; ++i)
> ia[i] = i;
> std::random_shuffle(ia, ia+N);
> @@ -76,4 +99,10 @@ int main()
> test<bidirectional_iterator<int*> >();
> test<random_access_iterator<int*> >();
> test<int*>();
> +
> +#ifndef TEST_STD_VER >= 11
> + test<bidirectional_iterator<S*> >();
> + test<random_access_iterator<S*> >();
> + test<S*>();
> +#endif // TEST_STD_VER >= 11
> }
>
> Modified: libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge_comp.pass.cpp
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge_comp.pass.cpp?rev=243530&r1=243529&r2=243530&view=diff
> ==============================================================================
> --- libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge_comp.pass.cpp (original)
> +++ libcxx/trunk/test/std/algorithms/alg.sorting/alg.merge/inplace_merge_comp.pass.cpp Wed Jul 29 11:25:45 2015
> @@ -18,7 +18,10 @@
> #include <algorithm>
> #include <functional>
> #include <cassert>
> -#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
> +
> +#include "test_macros.h"
> +
> +#ifndef TEST_STD_VER >= 11
> #include <memory>
>
> struct indirect_less
> @@ -28,7 +31,29 @@ struct indirect_less
> {return *x < *y;}
> };
>
> -#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES
> +struct S {
> + S() : i_(0) {}
> + S(int i) : i_(i) {}
> +
> + S(const S& rhs) : i_(rhs.i_) {}
> + S( S&& rhs) : i_(rhs.i_) { rhs.i_ = -1; }
> +
> + S& operator =(const S& rhs) { i_ = rhs.i_; return *this; }
> + S& operator =( S&& rhs) { i_ = rhs.i_; rhs.i_ = -2; assert(this != &rhs); return *this; }
> + S& operator =(int i) { i_ = i; return *this; }
> +
> + bool operator <(const S& rhs) const { return i_ < rhs.i_; }
> + bool operator >(const S& rhs) const { return i_ > rhs.i_; }
> + bool operator ==(const S& rhs) const { return i_ == rhs.i_; }
> + bool operator ==(int i) const { return i_ == i; }
> +
> + void set(int i) { i_ = i; }
> +
> + int i_;
> + };
> +
> +
> +#endif // TEST_STD_VER >= 11
>
> #include "test_iterators.h"
> #include "counting_predicates.hpp"
> @@ -38,19 +63,20 @@ void
> test_one(unsigned N, unsigned M)
> {
> assert(M <= N);
> - int* ia = new int[N];
> + typedef typename std::iterator_traits<Iter>::value_type value_type;
> + value_type* ia = new value_type[N];
> for (unsigned i = 0; i < N; ++i)
> ia[i] = i;
> std::random_shuffle(ia, ia+N);
> - std::sort(ia, ia+M, std::greater<int>());
> - std::sort(ia+M, ia+N, std::greater<int>());
> - binary_counting_predicate<std::greater<int>, int, int> pred((std::greater<int>()));
> + std::sort(ia, ia+M, std::greater<value_type>());
> + std::sort(ia+M, ia+N, std::greater<value_type>());
> + binary_counting_predicate<std::greater<value_type>, value_type, value_type> pred((std::greater<value_type>()));
> std::inplace_merge(Iter(ia), Iter(ia+M), Iter(ia+N), std::ref(pred));
> if(N > 0)
> {
> assert(ia[0] == N-1);
> assert(ia[N-1] == 0);
> - assert(std::is_sorted(ia, ia+N, std::greater<int>()));
> + assert(std::is_sorted(ia, ia+N, std::greater<value_type>()));
> assert(pred.count() <= (N-1));
> }
> delete [] ia;
> @@ -93,7 +119,11 @@ int main()
> test<random_access_iterator<int*> >();
> test<int*>();
>
> -#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
> +#ifndef TEST_STD_VER >= 11
> + test<bidirectional_iterator<S*> >();
> + test<random_access_iterator<S*> >();
> + test<S*>();
> +
> {
> unsigned N = 100;
> unsigned M = 50;
> @@ -112,5 +142,5 @@ int main()
> }
> delete [] ia;
> }
> -#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES
> +#endif // TEST_STD_VER >= 11
> }
>
>
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