[libcxx-commits] [libcxx] [libc++] Refactor memory allocation in basic_string (PR #128423)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Sun Feb 23 07:27:45 PST 2025
https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/128423
None
>From e0ab1dc2ddf5307c22dae81e4b68c286e0617f5a Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Fri, 7 Feb 2025 10:56:08 +0100
Subject: [PATCH] [libc++] Refactor memory allocation in basic_string
---
libcxx/include/__memory/allocate_at_least.h | 15 +-
libcxx/include/string | 265 +++++++-----------
libcxx/src/string.cpp | 19 +-
.../string.cons/copy_alloc.pass.cpp | 17 +-
4 files changed, 113 insertions(+), 203 deletions(-)
diff --git a/libcxx/include/__memory/allocate_at_least.h b/libcxx/include/__memory/allocate_at_least.h
index 9b5a8bcbd4596..eb9aa5d37fbd5 100644
--- a/libcxx/include/__memory/allocate_at_least.h
+++ b/libcxx/include/__memory/allocate_at_least.h
@@ -19,21 +19,22 @@
_LIBCPP_BEGIN_NAMESPACE_STD
+template <class _Pointer>
+struct __allocation_result {
+ _Pointer ptr;
+ size_t count;
+};
+
#if _LIBCPP_STD_VER >= 23
template <class _Alloc>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto __allocate_at_least(_Alloc& __alloc, size_t __n) {
- return std::allocator_traits<_Alloc>::allocate_at_least(__alloc, __n);
+ auto __res = std::allocator_traits<_Alloc>::allocate_at_least(__alloc, __n);
+ return __allocation_result{__res.ptr, __res.count};
}
#else
-template <class _Pointer>
-struct __allocation_result {
- _Pointer ptr;
- size_t count;
-};
-
template <class _Alloc>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI
_LIBCPP_CONSTEXPR __allocation_result<typename allocator_traits<_Alloc>::pointer>
diff --git a/libcxx/include/string b/libcxx/include/string
index 46bf13a5c900f..d0d9cd2b131e1 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -600,7 +600,6 @@ basic_string<char32_t> operator""s( const char32_t *str, size_t len );
# include <__functional/hash.h>
# include <__functional/unary_function.h>
# include <__fwd/string.h>
-# include <__ios/fpos.h>
# include <__iterator/bounded_iter.h>
# include <__iterator/distance.h>
# include <__iterator/iterator_traits.h>
@@ -643,7 +642,6 @@ basic_string<char32_t> operator""s( const char32_t *str, size_t len );
# include <__utility/move.h>
# include <__utility/scope_guard.h>
# include <__utility/swap.h>
-# include <__utility/unreachable.h>
# include <climits>
# include <cstdio> // EOF
# include <cstring>
@@ -814,6 +812,10 @@ private:
# ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
struct __long {
+ __long() = default;
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __long(size_type __cap, size_type __size, pointer __data)
+ : __data_(__data), __size_(__size), __cap_(__cap), __is_long_(true) {}
+
pointer __data_;
size_type __size_;
size_type __cap_ : sizeof(size_type) * CHAR_BIT - 1;
@@ -861,6 +863,13 @@ private:
// some platforms bit fields have a default size rather than the actual
// size used, e.g., it is 4 bytes on AIX. See D128285 for details.
struct __long {
+ __long() = default;
+
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __long(__allocation_result<pointer> __alloc, size_type __size)
+ : __is_long_(true), __cap_(__alloc.count / __endian_factor), __size_(__size), __data_(__alloc.ptr) {
+ _LIBCPP_ASSERT_INTERNAL(!__fits_in_sso(__alloc.count), "Long capacity should always be larger than the SSO");
+ }
+
struct _LIBCPP_PACKED {
size_type __is_long_ : 1;
size_type __cap_ : sizeof(size_type) * CHAR_BIT - 1;
@@ -906,20 +915,7 @@ private:
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(
__uninitialized_size_tag, size_type __size, const allocator_type& __a)
: __alloc_(__a) {
- if (__size > max_size())
- this->__throw_length_error();
- if (__fits_in_sso(__size)) {
- __rep_ = __rep();
- __set_short_size(__size);
- } else {
- auto __capacity = __recommend(__size) + 1;
- auto __allocation = __alloc_traits::allocate(__alloc_, __capacity);
- __begin_lifetime(__allocation, __capacity);
- __set_long_cap(__capacity);
- __set_long_pointer(__allocation);
- __set_long_size(__size);
- }
- __annotate_new(__size);
+ __init_internal_buffer(__size);
}
template <class _Iter, class _Sent>
@@ -1181,11 +1177,7 @@ public:
}
# endif // _LIBCPP_CXX03_LANG
- inline _LIBCPP_CONSTEXPR_SINCE_CXX20 ~basic_string() {
- __annotate_delete();
- if (__is_long())
- __alloc_traits::deallocate(__alloc_, __get_long_pointer(), __get_long_cap());
- }
+ inline _LIBCPP_CONSTEXPR_SINCE_CXX20 ~basic_string() { __reset_internal_buffer(); }
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 operator __self_view() const _NOEXCEPT {
return __self_view(typename __self_view::__assume_valid(), data(), size());
@@ -1995,18 +1987,6 @@ private:
return __rep_.__s.__is_long_;
}
- static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __begin_lifetime(pointer __begin, size_type __n) {
-# if _LIBCPP_STD_VER >= 20
- if (__libcpp_is_constant_evaluated()) {
- for (size_type __i = 0; __i != __n; ++__i)
- std::construct_at(std::addressof(__begin[__i]));
- }
-# else
- (void)__begin;
- (void)__n;
-# endif // _LIBCPP_STD_VER >= 20
- }
-
_LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI static bool __fits_in_sso(size_type __sz) { return __sz < __min_cap; }
template <class _Iterator, class _Sentinel>
@@ -2094,21 +2074,11 @@ private:
__set_short_size(__s);
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __set_long_cap(size_type __s) _NOEXCEPT {
- _LIBCPP_ASSERT_INTERNAL(!__fits_in_sso(__s), "Long capacity should always be larger than the SSO");
- __rep_.__l.__cap_ = __s / __endian_factor;
- __rep_.__l.__is_long_ = true;
- }
-
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type __get_long_cap() const _NOEXCEPT {
_LIBCPP_ASSERT_INTERNAL(__rep_.__l.__is_long_, "String has to be long when trying to get the long capacity");
return __rep_.__l.__cap_ * __endian_factor;
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __set_long_pointer(pointer __p) _NOEXCEPT {
- __rep_.__l.__data_ = __p;
- }
-
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pointer __get_long_pointer() _NOEXCEPT {
_LIBCPP_ASSERT_INTERNAL(__rep_.__l.__is_long_, "String has to be long when trying to get the long pointer");
return _LIBCPP_ASAN_VOLATILE_WRAPPER(__rep_.__l.__data_);
@@ -2136,6 +2106,58 @@ private:
return __is_long() ? __get_long_pointer() : __get_short_pointer();
}
+ _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX20 __allocation_result<pointer>
+ __allocate_long_buffer(_Allocator& __alloc, size_type __capacity) {
+ auto __buffer = std::__allocate_at_least(__alloc, __recommend(__capacity) + 1);
+
+ if (__libcpp_is_constant_evaluated()) {
+ for (size_type __i = 0; __i != __buffer.count; ++__i)
+ std::__construct_at(std::addressof(__buffer.ptr[__i]));
+ }
+
+ return __buffer;
+ }
+
+ _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX20 void
+ __deallocate_long_buffer(_Allocator& __alloc, __allocation_result<pointer> __allocation) {
+ __alloc_traits::deallocate(__alloc, __allocation.ptr, __allocation.count);
+ }
+
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __reset_internal_buffer() {
+ __annotate_delete();
+ if (__is_long())
+ __deallocate_long_buffer(__alloc_, __get_internal_long_buffer());
+ __rep_.__s = __short();
+ }
+
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __allocation_result<pointer> __get_internal_long_buffer() {
+ _LIBCPP_ASSERT_INTERNAL(__is_long(), "Trying to get buffer which doesn't exist!");
+ return __allocation_result<pointer>{__get_long_pointer(), __get_long_cap()};
+ }
+
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
+ __replace_internal_buffer(__allocation_result<pointer> __alloc, size_type __size) {
+ __reset_internal_buffer();
+ __rep_.__l = __long(__alloc, __size);
+ }
+
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pointer __init_internal_buffer(size_type __size) {
+ if (__libcpp_is_constant_evaluated())
+ __rep_ = __rep();
+
+ if (__size > max_size())
+ __throw_length_error();
+
+ if (__fits_in_sso(__size)) {
+ __set_short_size(__size);
+ __annotate_new(__size);
+ return __get_short_pointer();
+ }
+ __rep_.__l = __long(__allocate_long_buffer(__alloc_, __size), __size);
+ __annotate_new(__size);
+ return __get_long_pointer();
+ }
+
// The following functions are no-ops outside of AddressSanitizer mode.
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
__annotate_contiguous_container(const void* __old_mid, const void* __new_mid) const {
@@ -2293,24 +2315,15 @@ private:
__alloc_ = __str.__alloc_;
else {
if (!__str.__is_long()) {
- if (__is_long()) {
- __annotate_delete();
- __alloc_traits::deallocate(__alloc_, __get_long_pointer(), capacity() + 1);
- __rep_ = __rep();
- }
+ __reset_internal_buffer();
__alloc_ = __str.__alloc_;
} else {
__annotate_delete();
- auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
- allocator_type __a = __str.__alloc_;
- auto __allocation = std::__allocate_at_least(__a, __str.__get_long_cap());
- __begin_lifetime(__allocation.ptr, __allocation.count);
- if (__is_long())
- __alloc_traits::deallocate(__alloc_, __get_long_pointer(), __get_long_cap());
- __alloc_ = std::move(__a);
- __set_long_pointer(__allocation.ptr);
- __set_long_cap(__allocation.count);
- __set_long_size(__str.size());
+ auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
+ auto __alloc = __str.__alloc_;
+ auto __allocation = __allocate_long_buffer(__alloc, __str.size());
+ __replace_internal_buffer(__allocation, __str.size());
+ __alloc_ = std::move(__alloc);
}
}
}
@@ -2452,73 +2465,23 @@ basic_string(from_range_t, _Range&&, _Allocator = _Allocator())
template <class _CharT, class _Traits, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 void
basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz) {
- if (__libcpp_is_constant_evaluated())
- __rep_ = __rep();
- if (__sz > max_size())
- this->__throw_length_error();
- pointer __p;
- if (__fits_in_sso(__sz)) {
- __set_short_size(__sz);
- __p = __get_short_pointer();
- } else {
- auto __allocation = std::__allocate_at_least(__alloc_, __recommend(__sz) + 1);
- __p = __allocation.ptr;
- __begin_lifetime(__p, __allocation.count);
- __set_long_pointer(__p);
- __set_long_cap(__allocation.count);
- __set_long_size(__sz);
- }
+ pointer __p = __init_internal_buffer(__sz);
traits_type::copy(std::__to_address(__p), __s, __sz);
traits_type::assign(__p[__sz], value_type());
- __annotate_new(__sz);
}
template <class _CharT, class _Traits, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_NOINLINE void
basic_string<_CharT, _Traits, _Allocator>::__init_copy_ctor_external(const value_type* __s, size_type __sz) {
- if (__libcpp_is_constant_evaluated())
- __rep_ = __rep();
-
- pointer __p;
- if (__fits_in_sso(__sz)) {
- __p = __get_short_pointer();
- __set_short_size(__sz);
- } else {
- if (__sz > max_size())
- this->__throw_length_error();
- auto __allocation = std::__allocate_at_least(__alloc_, __recommend(__sz) + 1);
- __p = __allocation.ptr;
- __begin_lifetime(__p, __allocation.count);
- __set_long_pointer(__p);
- __set_long_cap(__allocation.count);
- __set_long_size(__sz);
- }
+ pointer __p = __init_internal_buffer(__sz);
traits_type::copy(std::__to_address(__p), __s, __sz + 1);
- __annotate_new(__sz);
}
template <class _CharT, class _Traits, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 void basic_string<_CharT, _Traits, _Allocator>::__init(size_type __n, value_type __c) {
- if (__libcpp_is_constant_evaluated())
- __rep_ = __rep();
-
- if (__n > max_size())
- this->__throw_length_error();
- pointer __p;
- if (__fits_in_sso(__n)) {
- __set_short_size(__n);
- __p = __get_short_pointer();
- } else {
- auto __allocation = std::__allocate_at_least(__alloc_, __recommend(__n) + 1);
- __p = __allocation.ptr;
- __begin_lifetime(__p, __allocation.count);
- __set_long_pointer(__p);
- __set_long_cap(__allocation.count);
- __set_long_size(__n);
- }
+ pointer __p = __init_internal_buffer(__n);
traits_type::assign(std::__to_address(__p), __n, __c);
traits_type::assign(__p[__n], value_type());
- __annotate_new(__n);
}
template <class _CharT, class _Traits, class _Allocator>
@@ -2542,9 +2505,7 @@ basic_string<_CharT, _Traits, _Allocator>::__init_with_sentinel(_InputIterator _
push_back(*__first);
# if _LIBCPP_HAS_EXCEPTIONS
} catch (...) {
- __annotate_delete();
- if (__is_long())
- __alloc_traits::deallocate(__alloc_, __get_long_pointer(), __get_long_cap());
+ __reset_internal_buffer();
throw;
}
# endif // _LIBCPP_HAS_EXCEPTIONS
@@ -2562,25 +2523,7 @@ template <class _CharT, class _Traits, class _Allocator>
template <class _InputIterator, class _Sentinel>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
basic_string<_CharT, _Traits, _Allocator>::__init_with_size(_InputIterator __first, _Sentinel __last, size_type __sz) {
- if (__libcpp_is_constant_evaluated())
- __rep_ = __rep();
-
- if (__sz > max_size())
- this->__throw_length_error();
-
- pointer __p;
- if (__fits_in_sso(__sz)) {
- __set_short_size(__sz);
- __p = __get_short_pointer();
-
- } else {
- auto __allocation = std::__allocate_at_least(__alloc_, __recommend(__sz) + 1);
- __p = __allocation.ptr;
- __begin_lifetime(__p, __allocation.count);
- __set_long_pointer(__p);
- __set_long_cap(__allocation.count);
- __set_long_size(__sz);
- }
+ pointer __p = __init_internal_buffer(__sz);
# if _LIBCPP_HAS_EXCEPTIONS
try {
@@ -2589,12 +2532,10 @@ basic_string<_CharT, _Traits, _Allocator>::__init_with_size(_InputIterator __fir
traits_type::assign(*__end, value_type());
# if _LIBCPP_HAS_EXCEPTIONS
} catch (...) {
- if (__is_long())
- __alloc_traits::deallocate(__alloc_, __get_long_pointer(), __get_long_cap());
+ __reset_internal_buffer();
throw;
}
# endif // _LIBCPP_HAS_EXCEPTIONS
- __annotate_new(__sz);
}
template <class _CharT, class _Traits, class _Allocator>
@@ -2614,9 +2555,8 @@ _LIBCPP_CONSTEXPR_SINCE_CXX20 void basic_string<_CharT, _Traits, _Allocator>::__
__old_cap < __ms / 2 - __alignment ? __recommend(std::max(__old_cap + __delta_cap, 2 * __old_cap)) : __ms - 1;
__annotate_delete();
auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
- auto __allocation = std::__allocate_at_least(__alloc_, __cap + 1);
+ auto __allocation = __allocate_long_buffer(__alloc_, __cap);
pointer __p = __allocation.ptr;
- __begin_lifetime(__p, __allocation.count);
if (__n_copy != 0)
traits_type::copy(std::__to_address(__p), std::__to_address(__old_p), __n_copy);
if (__n_add != 0)
@@ -2625,12 +2565,8 @@ _LIBCPP_CONSTEXPR_SINCE_CXX20 void basic_string<_CharT, _Traits, _Allocator>::__
if (__sec_cp_sz != 0)
traits_type::copy(
std::__to_address(__p) + __n_copy + __n_add, std::__to_address(__old_p) + __n_copy + __n_del, __sec_cp_sz);
- if (__old_cap + 1 != __min_cap)
- __alloc_traits::deallocate(__alloc_, __old_p, __old_cap + 1);
- __set_long_pointer(__p);
- __set_long_cap(__allocation.count);
__old_sz = __n_copy + __n_add + __sec_cp_sz;
- __set_long_size(__old_sz);
+ __replace_internal_buffer(__allocation, __old_sz);
traits_type::assign(__p[__old_sz], value_type());
}
@@ -2655,19 +2591,17 @@ _LIBCPP_DEPRECATED_("use __grow_by_without_replace") basic_string<_CharT, _Trait
pointer __old_p = __get_pointer();
size_type __cap =
__old_cap < __ms / 2 - __alignment ? __recommend(std::max(__old_cap + __delta_cap, 2 * __old_cap)) : __ms - 1;
- auto __allocation = std::__allocate_at_least(__alloc_, __cap + 1);
+ auto __allocation = __allocate_long_buffer(__alloc_, __cap);
pointer __p = __allocation.ptr;
- __begin_lifetime(__p, __allocation.count);
if (__n_copy != 0)
traits_type::copy(std::__to_address(__p), std::__to_address(__old_p), __n_copy);
size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
if (__sec_cp_sz != 0)
traits_type::copy(
std::__to_address(__p) + __n_copy + __n_add, std::__to_address(__old_p) + __n_copy + __n_del, __sec_cp_sz);
- if (__old_cap + 1 != __min_cap)
- __alloc_traits::deallocate(__alloc_, __old_p, __old_cap + 1);
- __set_long_pointer(__p);
- __set_long_cap(__allocation.count);
+ // This is -1 to make sure the caller sets the size properly, since old versions of this function didn't set the size
+ // at all.
+ __replace_internal_buffer(__allocation, -1);
}
template <class _CharT, class _Traits, class _Allocator>
@@ -2684,6 +2618,7 @@ basic_string<_CharT, _Traits, _Allocator>::__grow_by_without_replace(
_LIBCPP_SUPPRESS_DEPRECATED_PUSH
__grow_by(__old_cap, __delta_cap, __old_sz, __n_copy, __n_del, __n_add);
_LIBCPP_SUPPRESS_DEPRECATED_POP
+ // Due to the ABI of __grow_by we have to set the size after calling it.
__set_long_size(__old_sz - __n_del + __n_add);
}
@@ -2818,7 +2753,7 @@ basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, tr
{
__annotate_delete();
if (__is_long()) {
- __alloc_traits::deallocate(__alloc_, __get_long_pointer(), __get_long_cap());
+ __reset_internal_buffer();
# if _LIBCPP_STD_VER <= 14
if (!is_nothrow_move_assignable<allocator_type>::value) {
__set_short_size(0);
@@ -3454,15 +3389,10 @@ _LIBCPP_CONSTEXPR_SINCE_CXX20 void basic_string<_CharT, _Traits, _Allocator>::re
return;
__annotation_guard __g(*this);
- auto __allocation = std::__allocate_at_least(__alloc_, __recommend(__requested_capacity) + 1);
+ auto __allocation = __allocate_long_buffer(__alloc_, __requested_capacity);
auto __size = size();
- __begin_lifetime(__allocation.ptr, __allocation.count);
traits_type::copy(std::__to_address(__allocation.ptr), data(), __size + 1);
- if (__is_long())
- __alloc_traits::deallocate(__alloc_, __get_long_pointer(), __get_long_cap());
- __set_long_cap(__allocation.count);
- __set_long_size(__size);
- __set_long_pointer(__allocation.ptr);
+ __replace_internal_buffer(__allocation, __size);
}
template <class _CharT, class _Traits, class _Allocator>
@@ -3476,12 +3406,11 @@ inline _LIBCPP_CONSTEXPR_SINCE_CXX20 void basic_string<_CharT, _Traits, _Allocat
// We're a long string and we're shrinking into the small buffer.
if (__fits_in_sso(__target_capacity)) {
__annotation_guard __g(*this);
- auto __ptr = __get_long_pointer();
+ auto __allocation = __get_internal_long_buffer();
auto __size = __get_long_size();
- auto __cap = __get_long_cap();
- traits_type::copy(std::__to_address(__get_short_pointer()), std::__to_address(__ptr), __size + 1);
+ traits_type::copy(std::__to_address(__get_short_pointer()), std::__to_address(__allocation.ptr), __size + 1);
__set_short_size(__size);
- __alloc_traits::deallocate(__alloc_, __ptr, __cap);
+ __deallocate_long_buffer(__alloc_, __allocation);
return;
}
@@ -3490,22 +3419,18 @@ inline _LIBCPP_CONSTEXPR_SINCE_CXX20 void basic_string<_CharT, _Traits, _Allocat
# endif // _LIBCPP_HAS_EXCEPTIONS
__annotation_guard __g(*this);
auto __size = size();
- auto __allocation = std::__allocate_at_least(__alloc_, __target_capacity + 1);
+ auto __allocation = __allocate_long_buffer(__alloc_, size());
// The Standard mandates shrink_to_fit() does not increase the capacity.
// With equal capacity keep the existing buffer. This avoids extra work
// due to swapping the elements.
- if (__allocation.count - 1 >= capacity()) {
- __alloc_traits::deallocate(__alloc_, __allocation.ptr, __allocation.count);
+ if (__allocation.count - 1 > capacity()) {
+ __deallocate_long_buffer(__alloc_, __allocation);
return;
}
- __begin_lifetime(__allocation.ptr, __allocation.count);
- auto __ptr = __get_long_pointer();
- traits_type::copy(std::__to_address(__allocation.ptr), std::__to_address(__ptr), __size + 1);
- __alloc_traits::deallocate(__alloc_, __ptr, __get_long_cap());
- __set_long_cap(__allocation.count);
- __set_long_pointer(__allocation.ptr);
+ traits_type::copy(std::__to_address(__allocation.ptr), std::__to_address(__get_long_pointer()), __size + 1);
+ __replace_internal_buffer(__allocation, size());
# if _LIBCPP_HAS_EXCEPTIONS
} catch (...) {
return;
diff --git a/libcxx/src/string.cpp b/libcxx/src/string.cpp
index e335639883dba..49e5f8f73445a 100644
--- a/libcxx/src/string.cpp
+++ b/libcxx/src/string.cpp
@@ -44,22 +44,9 @@ void __basic_string_common<true>::__throw_out_of_range() const { std::__throw_ou
template <class _CharT, class _Traits, class _Allocator>
void basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz, size_type __reserve) {
- if (__libcpp_is_constant_evaluated())
- __rep_ = __rep();
- if (__reserve > max_size())
- __throw_length_error();
- pointer __p;
- if (__fits_in_sso(__reserve)) {
- __set_short_size(__sz);
- __p = __get_short_pointer();
- } else {
- auto __allocation = std::__allocate_at_least(__alloc_, __recommend(__reserve) + 1);
- __p = __allocation.ptr;
- __begin_lifetime(__p, __allocation.count);
- __set_long_pointer(__p);
- __set_long_cap(__allocation.count);
- __set_long_size(__sz);
- }
+ pointer __p = __init_internal_buffer(__reserve);
+ __annotate_delete();
+ __set_size(__sz);
traits_type::copy(std::__to_address(__p), __s, __sz);
traits_type::assign(__p[__sz], value_type());
__annotate_new(__sz);
diff --git a/libcxx/test/std/strings/basic.string/string.cons/copy_alloc.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/copy_alloc.pass.cpp
index b0045cb4afbba..f074ce0bc4ce0 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/copy_alloc.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/copy_alloc.pass.cpp
@@ -66,15 +66,6 @@ bool operator!=(const poca_alloc<T>& lhs, const poca_alloc<U>& rhs) {
return lhs.imp != rhs.imp;
}
-template <class S>
-TEST_CONSTEXPR_CXX20 void test_assign(S& s1, const S& s2) {
- try {
- s1 = s2;
- } catch (std::bad_alloc&) {
- return;
- }
- assert(false);
-}
#endif
template <class S>
@@ -122,7 +113,13 @@ TEST_CONSTEXPR_CXX20 bool test() {
assert(s2 == p2);
imp2.deactivate();
- test_assign(s1, s2);
+
+ try {
+ s1 = s2;
+ assert(false);
+ } catch (std::bad_alloc&) {
+ }
+
assert(s1 == p1);
assert(s2 == p2);
}
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