From ce615e67bbe070bf70f0ccd9c827ff0902060abb Mon Sep 17 00:00:00 2001 From: Louis Dionne Date: Fri, 17 Nov 2023 14:31:50 -0500 Subject: [PATCH] [libc++] Remove deprecated char_traits base template This patch has quite a bit of history. First, it must be noted that the Standard only specifies specializations of char_traits for char, char8_t, char16_t, char32_t and wchar_t. However, before this patch, we would provide a base template that accepted anything, and as a result code like `std::basic_string` would compile but nobody knows what it really does. It basically compiles by accident. We marked the base template as deprecated in LLVM 15 or 16 and were planning on removing it in LLVM 17, which we did in e30a148b098d. However, it turned out that the deprecation warning had never been visible in user code since Clang did not surface that warning from system headers. As a result, this caught people by surprise and we decided to reintroduce the base template in LLVM 17 in cce062d226ba. Since then, #70353 changed Clang so that such deprecation warnings would be visible from user code. Hence, this patch closes the loop and removes the deprecated specializations. --- libcxx/docs/ReleaseNotes/19.rst | 2 +- libcxx/include/__string/char_traits.h | 100 ------------ .../arbitrary_char_type.deprecated.verify.cpp | 21 --- .../arbitrary_char_type.pass.cpp | 146 ------------------ 4 files changed, 1 insertion(+), 268 deletions(-) delete mode 100644 libcxx/test/libcxx/strings/char.traits/char.traits.specializations/arbitrary_char_type.deprecated.verify.cpp delete mode 100644 libcxx/test/libcxx/strings/char.traits/char.traits.specializations/arbitrary_char_type.pass.cpp diff --git a/libcxx/docs/ReleaseNotes/19.rst b/libcxx/docs/ReleaseNotes/19.rst index 17a0415a8ad436..ecf6569cf43fbd 100644 --- a/libcxx/docs/ReleaseNotes/19.rst +++ b/libcxx/docs/ReleaseNotes/19.rst @@ -56,7 +56,7 @@ Deprecations and Removals the LLVM 19 release while also issuing a deprecation warning). See :ref:`the hardening documentation ` for more details. -- TODO: The base template for ``std::char_traits`` has been removed in LLVM 19. If you are using ``std::char_traits`` with +- The base template for ``std::char_traits`` has been removed in LLVM 19. If you are using ``std::char_traits`` with types other than ``char``, ``wchar_t``, ``char8_t``, ``char16_t``, ``char32_t`` or a custom character type for which you specialized ``std::char_traits``, your code will stop working. The Standard does not mandate that a base template is provided, and such a base template is bound to be incorrect for some types, which could currently cause unexpected behavior diff --git a/libcxx/include/__string/char_traits.h b/libcxx/include/__string/char_traits.h index e3563c57fea0cd..8ea9625d071834 100644 --- a/libcxx/include/__string/char_traits.h +++ b/libcxx/include/__string/char_traits.h @@ -72,106 +72,6 @@ exposition-only to document what members a char_traits specialization should pro }; */ -// -// Temporary extension to provide a base template for std::char_traits. -// TODO(LLVM-19): Remove this class. -// -#if !defined(_LIBCPP_CHAR_TRAITS_REMOVE_BASE_SPECIALIZATION) -template -struct _LIBCPP_DEPRECATED_( - "char_traits for T not equal to char, wchar_t, char8_t, char16_t or char32_t is non-standard and is provided " - "for a temporary period. It will be removed in LLVM 19, so please migrate off of it.") char_traits { - using char_type = _CharT; - using int_type = int; - using off_type = streamoff; - using pos_type = streampos; - using state_type = mbstate_t; - - static inline void _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_HIDE_FROM_ABI - assign(char_type& __c1, const char_type& __c2) _NOEXCEPT { - __c1 = __c2; - } - static inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT { - return __c1 == __c2; - } - static inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT { - return __c1 < __c2; - } - - static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 int - compare(const char_type* __s1, const char_type* __s2, size_t __n) { - for (; __n; --__n, ++__s1, ++__s2) { - if (lt(*__s1, *__s2)) - return -1; - if (lt(*__s2, *__s1)) - return 1; - } - return 0; - } - _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX17 size_t length(const char_type* __s) { - size_t __len = 0; - for (; !eq(*__s, char_type(0)); ++__s) - ++__len; - return __len; - } - _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX17 const char_type* - find(const char_type* __s, size_t __n, const char_type& __a) { - for (; __n; --__n) { - if (eq(*__s, __a)) - return __s; - ++__s; - } - return nullptr; - } - static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 char_type* - move(char_type* __s1, const char_type* __s2, size_t __n) { - if (__n == 0) - return __s1; - char_type* __r = __s1; - if (__s1 < __s2) { - for (; __n; --__n, ++__s1, ++__s2) - assign(*__s1, *__s2); - } else if (__s2 < __s1) { - __s1 += __n; - __s2 += __n; - for (; __n; --__n) - assign(*--__s1, *--__s2); - } - return __r; - } - _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX20 char_type* - copy(char_type* __s1, const char_type* __s2, size_t __n) { - _LIBCPP_ASSERT_NON_OVERLAPPING_RANGES(!std::__is_pointer_in_range(__s1, __s1 + __n, __s2), - "char_traits::copy: source and destination ranges overlap"); - char_type* __r = __s1; - for (; __n; --__n, ++__s1, ++__s2) - assign(*__s1, *__s2); - return __r; - } - _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX20 char_type* - assign(char_type* __s, size_t __n, char_type __a) { - char_type* __r = __s; - for (; __n; --__n, ++__s) - assign(*__s, __a); - return __r; - } - - static inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int_type not_eof(int_type __c) _NOEXCEPT { - return eq_int_type(__c, eof()) ? ~eof() : __c; - } - static inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT { - return char_type(__c); - } - static inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT { - return int_type(__c); - } - static inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT { - return __c1 == __c2; - } - static inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT { return int_type(EOF); } -}; -#endif // !defined(_LIBCPP_CHAR_TRAITS_REMOVE_BASE_SPECIALIZATION) - // char_traits template <> diff --git a/libcxx/test/libcxx/strings/char.traits/char.traits.specializations/arbitrary_char_type.deprecated.verify.cpp b/libcxx/test/libcxx/strings/char.traits/char.traits.specializations/arbitrary_char_type.deprecated.verify.cpp deleted file mode 100644 index ec6f34ef5462e6..00000000000000 --- a/libcxx/test/libcxx/strings/char.traits/char.traits.specializations/arbitrary_char_type.deprecated.verify.cpp +++ /dev/null @@ -1,21 +0,0 @@ -//===----------------------------------------------------------------------===// -// -// 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 -// -//===----------------------------------------------------------------------===// - -// - -// template<> struct char_traits for arbitrary T - -// Make sure we issue deprecation warnings. - -#include - -void f() { - std::char_traits t1; (void)t1; // expected-warning{{'char_traits' is deprecated}} - std::char_traits t2; (void)t2; // expected-warning{{'char_traits' is deprecated}} - std::char_traits t3; (void)t3; // expected-warning{{'char_traits' is deprecated}} -} diff --git a/libcxx/test/libcxx/strings/char.traits/char.traits.specializations/arbitrary_char_type.pass.cpp b/libcxx/test/libcxx/strings/char.traits/char.traits.specializations/arbitrary_char_type.pass.cpp deleted file mode 100644 index c2de29d22b2fe4..00000000000000 --- a/libcxx/test/libcxx/strings/char.traits/char.traits.specializations/arbitrary_char_type.pass.cpp +++ /dev/null @@ -1,146 +0,0 @@ -//===----------------------------------------------------------------------===// -// -// 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 -// -//===----------------------------------------------------------------------===// - -// - -// template<> struct char_traits for arbitrary T - -// Non-standard but provided temporarily for users to migrate. - -// ADDITIONAL_COMPILE_FLAGS: -Wno-deprecated - -#include -#include -#include - -#include "test_macros.h" - -template -TEST_CONSTEXPR_CXX20 bool test() { - static_assert(std::is_same::char_type, Char>::value, ""); - static_assert(std::is_same::int_type, int>::value, ""); - static_assert(std::is_same::off_type, std::streamoff>::value, ""); - static_assert(std::is_same::pos_type, std::streampos>::value, ""); - static_assert(std::is_same::state_type, std::mbstate_t>::value, ""); - - assert(std::char_traits::to_int_type(Char('a')) == Char('a')); - assert(std::char_traits::to_int_type(Char('A')) == Char('A')); - assert(std::char_traits::to_int_type(0) == 0); - - assert(std::char_traits::to_char_type(Char('a')) == Char('a')); - assert(std::char_traits::to_char_type(Char('A')) == Char('A')); - assert(std::char_traits::to_char_type(0) == 0); - - assert(std::char_traits::eof() == EOF); - - assert(std::char_traits::not_eof(Char('a')) == Char('a')); - assert(std::char_traits::not_eof(Char('A')) == Char('A')); - assert(std::char_traits::not_eof(0) == 0); - assert(std::char_traits::not_eof(std::char_traits::eof()) != - std::char_traits::eof()); - - assert(std::char_traits::lt(Char('\0'), Char('A')) == (Char('\0') < Char('A'))); - assert(std::char_traits::lt(Char('A'), Char('\0')) == (Char('A') < Char('\0'))); - assert(std::char_traits::lt(Char('a'), Char('a')) == (Char('a') < Char('a'))); - assert(std::char_traits::lt(Char('A'), Char('a')) == (Char('A') < Char('a'))); - assert(std::char_traits::lt(Char('a'), Char('A')) == (Char('a') < Char('A'))); - - assert( std::char_traits::eq(Char('a'), Char('a'))); - assert(!std::char_traits::eq(Char('a'), Char('A'))); - - assert( std::char_traits::eq_int_type(Char('a'), Char('a'))); - assert(!std::char_traits::eq_int_type(Char('a'), Char('A'))); - assert(!std::char_traits::eq_int_type(std::char_traits::eof(), Char('A'))); - assert( std::char_traits::eq_int_type(std::char_traits::eof(), std::char_traits::eof())); - - { - Char s1[] = {1, 2, 3, 0}; - Char s2[] = {0}; - assert(std::char_traits::length(s1) == 3); - assert(std::char_traits::length(s2) == 0); - } - - { - Char s1[] = {1, 2, 3}; - assert(std::char_traits::find(s1, 3, Char(1)) == s1); - assert(std::char_traits::find(s1, 3, Char(2)) == s1+1); - assert(std::char_traits::find(s1, 3, Char(3)) == s1+2); - assert(std::char_traits::find(s1, 3, Char(4)) == 0); - assert(std::char_traits::find(s1, 3, Char(0)) == 0); - assert(std::char_traits::find(NULL, 0, Char(0)) == 0); - } - - { - Char s1[] = {1, 2, 3}; - Char s2[3] = {0}; - assert(std::char_traits::copy(s2, s1, 3) == s2); - assert(s2[0] == Char(1)); - assert(s2[1] == Char(2)); - assert(s2[2] == Char(3)); - assert(std::char_traits::copy(NULL, s1, 0) == NULL); - assert(std::char_traits::copy(s1, NULL, 0) == s1); - } - - { - Char s1[] = {1, 2, 3}; - assert(std::char_traits::move(s1, s1+1, 2) == s1); - assert(s1[0] == Char(2)); - assert(s1[1] == Char(3)); - assert(s1[2] == Char(3)); - s1[2] = Char(0); - assert(std::char_traits::move(s1+1, s1, 2) == s1+1); - assert(s1[0] == Char(2)); - assert(s1[1] == Char(2)); - assert(s1[2] == Char(3)); - assert(std::char_traits::move(NULL, s1, 0) == NULL); - assert(std::char_traits::move(s1, NULL, 0) == s1); - } - - { - Char s1[] = {0}; - assert(std::char_traits::compare(s1, s1, 0) == 0); - assert(std::char_traits::compare(NULL, NULL, 0) == 0); - - Char s2[] = {1, 0}; - Char s3[] = {2, 0}; - assert(std::char_traits::compare(s2, s2, 1) == 0); - assert(std::char_traits::compare(s2, s3, 1) < 0); - assert(std::char_traits::compare(s3, s2, 1) > 0); - } - - { - Char s2[3] = {0}; - assert(std::char_traits::assign(s2, 3, Char(5)) == s2); - assert(s2[0] == Char(5)); - assert(s2[1] == Char(5)); - assert(s2[2] == Char(5)); - assert(std::char_traits::assign(NULL, 0, Char(5)) == NULL); - } - - { - Char c = Char('\0'); - std::char_traits::assign(c, Char('a')); - assert(c == Char('a')); - } - - return true; -} - -int main(int, char**) { - test(); - test(); - test(); - -#if TEST_STD_VER > 17 - static_assert(test()); - static_assert(test()); - static_assert(test()); -#endif - - return 0; -}