diff --git a/libcxx/include/__config b/libcxx/include/__config --- a/libcxx/include/__config +++ b/libcxx/include/__config @@ -1001,6 +1001,12 @@ # define _LIBCPP_DEPRECATED_IN_CXX17 #endif +#if _LIBCPP_STD_VER > 17 +# define _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_DEPRECATED +#else +# define _LIBCPP_DEPRECATED_IN_CXX20 +#endif + // Macros to enter and leave a state where deprecation warnings are suppressed. #if !defined(_LIBCPP_SUPPRESS_DEPRECATED_PUSH) && \ (defined(_LIBCPP_COMPILER_CLANG) || defined(_LIBCPP_COMPILER_GCC)) diff --git a/libcxx/include/string b/libcxx/include/string --- a/libcxx/include/string +++ b/libcxx/include/string @@ -153,7 +153,8 @@ void resize(size_type n, value_type c); void resize(size_type n); - void reserve(size_type res_arg = 0); + void reserve(size_type res_arg); + void reserve(); // deprecated in C++20 void shrink_to_fit(); void clear() noexcept; bool empty() const noexcept; @@ -957,10 +958,10 @@ void reserve(size_type __res_arg); _LIBCPP_INLINE_VISIBILITY void __resize_default_init(size_type __n); + _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY + void reserve() _NOEXCEPT {shrink_to_fit();} _LIBCPP_INLINE_VISIBILITY - void reserve() _NOEXCEPT {reserve(0);} - _LIBCPP_INLINE_VISIBILITY - void shrink_to_fit() _NOEXCEPT {reserve();} + void shrink_to_fit() _NOEXCEPT; _LIBCPP_INLINE_VISIBILITY void clear() _NOEXCEPT; _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY @@ -1418,6 +1419,8 @@ _LIBCPP_INLINE_VISIBILITY void __clear_and_shrink() _NOEXCEPT; + _LIBCPP_INLINE_VISIBILITY void __shrink_or_extend(size_type __res_arg); + _LIBCPP_INLINE_VISIBILITY bool __is_long() const _NOEXCEPT {return bool(__r_.first().__s.__size_ & __short_mask);} @@ -3266,61 +3269,84 @@ { if (__res_arg > max_size()) this->__throw_length_error(); + +#if _LIBCPP_STD_VER > 17 + // Reserve never shrinks as of C++20. + if (__res_arg <= capacity()) return; +#endif + + __res_arg = _VSTD::max(__res_arg, size()); + __res_arg = __recommend(__res_arg); + if (__res_arg == capacity()) return; + + __shrink_or_extend(__res_arg); +} + +template +void +basic_string<_CharT, _Traits, _Allocator>::shrink_to_fit() _NOEXCEPT +{ + size_type __res_arg = __recommend(size()); + if (__res_arg == capacity()) return; + + __shrink_or_extend(__res_arg); +} + +template +void +basic_string<_CharT, _Traits, _Allocator>::__shrink_or_extend(size_type __res_arg) +{ size_type __cap = capacity(); size_type __sz = size(); - __res_arg = _VSTD::max(__res_arg, __sz); - __res_arg = __recommend(__res_arg); - if (__res_arg != __cap) + + pointer __new_data, __p; + bool __was_long, __now_long; + if (__res_arg == __min_cap - 1) { - pointer __new_data, __p; - bool __was_long, __now_long; - if (__res_arg == __min_cap - 1) - { - __was_long = true; - __now_long = false; - __new_data = __get_short_pointer(); - __p = __get_long_pointer(); - } + __was_long = true; + __now_long = false; + __new_data = __get_short_pointer(); + __p = __get_long_pointer(); + } + else + { + if (__res_arg > __cap) + __new_data = __alloc_traits::allocate(__alloc(), __res_arg+1); else { - if (__res_arg > __cap) + #ifndef _LIBCPP_NO_EXCEPTIONS + try + { + #endif // _LIBCPP_NO_EXCEPTIONS __new_data = __alloc_traits::allocate(__alloc(), __res_arg+1); - else + #ifndef _LIBCPP_NO_EXCEPTIONS + } + catch (...) { - #ifndef _LIBCPP_NO_EXCEPTIONS - try - { - #endif // _LIBCPP_NO_EXCEPTIONS - __new_data = __alloc_traits::allocate(__alloc(), __res_arg+1); - #ifndef _LIBCPP_NO_EXCEPTIONS - } - catch (...) - { - return; - } - #else // _LIBCPP_NO_EXCEPTIONS - if (__new_data == nullptr) - return; - #endif // _LIBCPP_NO_EXCEPTIONS + return; } - __now_long = true; - __was_long = __is_long(); - __p = __get_pointer(); - } - traits_type::copy(_VSTD::__to_address(__new_data), - _VSTD::__to_address(__p), size()+1); - if (__was_long) - __alloc_traits::deallocate(__alloc(), __p, __cap+1); - if (__now_long) - { - __set_long_cap(__res_arg+1); - __set_long_size(__sz); - __set_long_pointer(__new_data); + #else // _LIBCPP_NO_EXCEPTIONS + if (__new_data == nullptr) + return; + #endif // _LIBCPP_NO_EXCEPTIONS } - else - __set_short_size(__sz); - __invalidate_all_iterators(); + __now_long = true; + __was_long = __is_long(); + __p = __get_pointer(); + } + traits_type::copy(_VSTD::__to_address(__new_data), + _VSTD::__to_address(__p), size()+1); + if (__was_long) + __alloc_traits::deallocate(__alloc(), __p, __cap+1); + if (__now_long) + { + __set_long_cap(__res_arg+1); + __set_long_size(__sz); + __set_long_pointer(__new_data); } + else + __set_short_size(__sz); + __invalidate_all_iterators(); } template diff --git a/libcxx/test/libcxx/strings/basic.string/string.capacity/reserve.pass.cpp b/libcxx/test/libcxx/strings/basic.string/string.capacity/reserve.pass.cpp new file mode 100644 --- /dev/null +++ b/libcxx/test/libcxx/strings/basic.string/string.capacity/reserve.pass.cpp @@ -0,0 +1,50 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +// + +// void reserve(); // Deprecated in C++20. + +// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS + +#include +#include +#include + +#include "test_macros.h" +#include "min_allocator.h" + +template +void +test() +{ + // Tests that a call to reserve() on a long string is equivalent to shrink_to_fit(). + S s(1000, 'a'); + typename S::size_type old_cap = s.capacity(); + s.resize(20); + assert(s.capacity() == old_cap); + s.reserve(); + assert(s.capacity() < old_cap); +} + +int main(int, char**) +{ + { + typedef std::string S; + test(); + } +#if TEST_STD_VER >= 11 + { + typedef min_allocator A; + typedef std::basic_string, A> S; + test(); + } +#endif + + return 0; +} diff --git a/libcxx/test/std/strings/basic.string/string.capacity/reserve.deprecated_in_cxx20.verify.cpp b/libcxx/test/std/strings/basic.string/string.capacity/reserve.deprecated_in_cxx20.verify.cpp new file mode 100644 --- /dev/null +++ b/libcxx/test/std/strings/basic.string/string.capacity/reserve.deprecated_in_cxx20.verify.cpp @@ -0,0 +1,22 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +// + +// void reserve(); // Deprecated in C++20 + +// UNSUPPORTED: c++03, c++11, c++14, c++17 + +#include + +int main(int, char**) +{ + std::string s; + s.reserve(); // expected-warning {{'reserve' is deprecated}} + return 0; +} diff --git a/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp --- a/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp +++ b/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp @@ -8,9 +8,9 @@ // -// Split into two calls for C++20 -// void reserve(); -// void reserve(size_type res_arg); +// void reserve(); // Deprecated in C++20. + +// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS #include #include @@ -21,8 +21,13 @@ template void -test(S s) +test(typename S::size_type min_cap, typename S::size_type erased_index) { + S s(min_cap, 'a'); + s.erase(erased_index); + assert(s.size() == erased_index); + assert(s.capacity() >= min_cap); // Check that we really have at least this capacity. + typename S::size_type old_cap = s.capacity(); S s0 = s; s.reserve(); @@ -32,102 +37,23 @@ assert(s.capacity() >= s.size()); } -template -void -test(S s, typename S::size_type res_arg) -{ - typename S::size_type old_cap = s.capacity(); - ((void)old_cap); // Prevent unused warning - S s0 = s; - if (res_arg <= s.max_size()) - { - s.reserve(res_arg); - assert(s == s0); - assert(s.capacity() >= res_arg); - assert(s.capacity() >= s.size()); -#if TEST_STD_VER > 17 - assert(s.capacity() >= old_cap); // resize never shrinks as of P0966 -#endif - } -#ifndef TEST_HAS_NO_EXCEPTIONS - else - { - try - { - s.reserve(res_arg); - assert(false); - } - catch (std::length_error&) - { - assert(res_arg > s.max_size()); - } - } -#endif -} - int main(int, char**) { { typedef std::string S; { - S s; - test(s); - - s.assign(10, 'a'); - s.erase(5); - test(s); - - s.assign(100, 'a'); - s.erase(50); - test(s); - } - { - S s; - test(s, 5); - test(s, 10); - test(s, 50); - } - { - S s(100, 'a'); - s.erase(50); - test(s, 5); - test(s, 10); - test(s, 50); - test(s, 100); - test(s, 1000); - test(s, S::npos); + test(0, 0); + test(10, 5); + test(100, 50); } } #if TEST_STD_VER >= 11 { typedef std::basic_string, min_allocator> S; { - S s; - test(s); - - s.assign(10, 'a'); - s.erase(5); - test(s); - - s.assign(100, 'a'); - s.erase(50); - test(s); - } - { - S s; - test(s, 5); - test(s, 10); - test(s, 50); - } - { - S s(100, 'a'); - s.erase(50); - test(s, 5); - test(s, 10); - test(s, 50); - test(s, 100); - test(s, 1000); - test(s, S::npos); + test(0, 0); + test(10, 5); + test(100, 50); } } #endif diff --git a/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/reserve_size.pass.cpp copy from libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp copy to libcxx/test/std/strings/basic.string/string.capacity/reserve_size.pass.cpp --- a/libcxx/test/std/strings/basic.string/string.capacity/reserve.pass.cpp +++ b/libcxx/test/std/strings/basic.string/string.capacity/reserve_size.pass.cpp @@ -8,8 +8,6 @@ // -// Split into two calls for C++20 -// void reserve(); // void reserve(size_type res_arg); #include @@ -21,23 +19,16 @@ template void -test(S s) +test(typename S::size_type min_cap, typename S::size_type erased_index, typename S::size_type res_arg) { - typename S::size_type old_cap = s.capacity(); - S s0 = s; - s.reserve(); - LIBCPP_ASSERT(s.__invariants()); - assert(s == s0); - assert(s.capacity() <= old_cap); - assert(s.capacity() >= s.size()); -} + S s(min_cap, 'a'); + s.erase(erased_index); + assert(s.size() == erased_index); + assert(s.capacity() >= min_cap); // Check that we really have at least this capacity. -template -void -test(S s, typename S::size_type res_arg) -{ +#if TEST_STD_VER > 17 typename S::size_type old_cap = s.capacity(); - ((void)old_cap); // Prevent unused warning +#endif S s0 = s; if (res_arg <= s.max_size()) { @@ -46,7 +37,7 @@ assert(s.capacity() >= res_arg); assert(s.capacity() >= s.size()); #if TEST_STD_VER > 17 - assert(s.capacity() >= old_cap); // resize never shrinks as of P0966 + assert(s.capacity() >= old_cap); // reserve never shrinks as of P0966 (C++20) #endif } #ifndef TEST_HAS_NO_EXCEPTIONS @@ -70,64 +61,34 @@ { typedef std::string S; { - S s; - test(s); - - s.assign(10, 'a'); - s.erase(5); - test(s); - - s.assign(100, 'a'); - s.erase(50); - test(s); - } - { - S s; - test(s, 5); - test(s, 10); - test(s, 50); + test(0, 0, 5); + test(0, 0, 10); + test(0, 0, 50); } { - S s(100, 'a'); - s.erase(50); - test(s, 5); - test(s, 10); - test(s, 50); - test(s, 100); - test(s, 1000); - test(s, S::npos); + test(100, 50, 5); + test(100, 50, 10); + test(100, 50, 50); + test(100, 50, 100); + test(100, 50, 1000); + test(100, 50, S::npos); } } #if TEST_STD_VER >= 11 { typedef std::basic_string, min_allocator> S; { - S s; - test(s); - - s.assign(10, 'a'); - s.erase(5); - test(s); - - s.assign(100, 'a'); - s.erase(50); - test(s); - } - { - S s; - test(s, 5); - test(s, 10); - test(s, 50); + test(0, 0, 5); + test(0, 0, 10); + test(0, 0, 50); } { - S s(100, 'a'); - s.erase(50); - test(s, 5); - test(s, 10); - test(s, 50); - test(s, 100); - test(s, 1000); - test(s, S::npos); + test(100, 50, 5); + test(100, 50, 10); + test(100, 50, 50); + test(100, 50, 100); + test(100, 50, 1000); + test(100, 50, S::npos); } } #endif diff --git a/libcxx/www/cxx2a_status.html b/libcxx/www/cxx2a_status.html --- a/libcxx/www/cxx2a_status.html +++ b/libcxx/www/cxx2a_status.html @@ -79,7 +79,7 @@ P0809R0LWGComparing Unordered ContainersJacksonville P0858R0LWGConstexpr iterator requirementsJacksonville P0905R1CWGSymmetry for spaceshipJacksonville - P0966R1LWGstring::reserve Should Not ShrinkJacksonvilleComplete8.0 + P0966R1LWGstring::reserve Should Not ShrinkJacksonvilleComplete12.0 P0019R8LWGAtomic RefRapperswil @@ -263,6 +263,7 @@

The missing bits in P0202 are in copy and copy_backwards (and the ones that call them: copy_n, set_union, set_difference, and set_symmetric_difference). This is because the first two algorithms have specializations that call memmove which is not constexpr. See Bug 25165

+

P0966 was previosly erroneously marked as complete in version 8.0. See Bug 45368

Library Working group Issues Status