[libcxx-commits] [libcxx] r371068 - [libc++] Revert "Make `vector` unconditionally move elements when exceptions are disabled."
Louis Dionne via libcxx-commits
libcxx-commits at lists.llvm.org
Thu Sep 5 06:50:28 PDT 2019
Author: ldionne
Date: Thu Sep 5 06:50:28 2019
New Revision: 371068
URL: http://llvm.org/viewvc/llvm-project?rev=371068&view=rev
Log:
[libc++] Revert "Make `vector` unconditionally move elements when exceptions are disabled."
This reverts r370502, which broke the use case of a copy-only T (with a
deleted move constructor) when exceptions are disabled. Until we figure
out the right behavior, I'm reverting the commit.
Removed:
libcxx/trunk/test/libcxx/containers/sequences/vector/exception_safety_exceptions_disabled.sh.cpp
Modified:
libcxx/trunk/include/memory
libcxx/trunk/include/vector
Modified: libcxx/trunk/include/memory
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/memory?rev=371068&r1=371067&r2=371068&view=diff
==============================================================================
--- libcxx/trunk/include/memory (original)
+++ libcxx/trunk/include/memory Thu Sep 5 06:50:28 2019
@@ -1609,16 +1609,10 @@ struct _LIBCPP_TEMPLATE_VIS allocator_tr
_LIBCPP_INLINE_VISIBILITY
static
void
- __construct_forward_with_exception_guarantees(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __begin2)
+ __construct_forward(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __begin2)
{
for (; __begin1 != __end1; ++__begin1, (void) ++__begin2)
- construct(__a, _VSTD::__to_raw_pointer(__begin2),
-#ifdef _LIBCPP_NO_EXCEPTIONS
- _VSTD::move(*__begin1)
-#else
- _VSTD::move_if_noexcept(*__begin1)
-#endif
- );
+ construct(__a, _VSTD::__to_raw_pointer(__begin2), _VSTD::move_if_noexcept(*__begin1));
}
template <class _Tp>
@@ -1631,7 +1625,7 @@ struct _LIBCPP_TEMPLATE_VIS allocator_tr
is_trivially_move_constructible<_Tp>::value,
void
>::type
- __construct_forward_with_exception_guarantees(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __begin2)
+ __construct_forward(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __begin2)
{
ptrdiff_t _Np = __end1 - __begin1;
if (_Np > 0)
@@ -1678,18 +1672,12 @@ struct _LIBCPP_TEMPLATE_VIS allocator_tr
_LIBCPP_INLINE_VISIBILITY
static
void
- __construct_backward_with_exception_guarantees(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __end2)
+ __construct_backward(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __end2)
{
while (__end1 != __begin1)
{
- construct(__a, _VSTD::__to_raw_pointer(__end2 - 1),
-#ifdef _LIBCPP_NO_EXCEPTIONS
- _VSTD::move(*--__end1)
-#else
- _VSTD::move_if_noexcept(*--__end1)
-#endif
- );
- --__end2;
+ construct(__a, _VSTD::__to_raw_pointer(__end2-1), _VSTD::move_if_noexcept(*--__end1));
+ --__end2;
}
}
@@ -1703,7 +1691,7 @@ struct _LIBCPP_TEMPLATE_VIS allocator_tr
is_trivially_move_constructible<_Tp>::value,
void
>::type
- __construct_backward_with_exception_guarantees(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __end2)
+ __construct_backward(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __end2)
{
ptrdiff_t _Np = __end1 - __begin1;
__end2 -= _Np;
Modified: libcxx/trunk/include/vector
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/vector?rev=371068&r1=371067&r2=371068&view=diff
==============================================================================
--- libcxx/trunk/include/vector (original)
+++ libcxx/trunk/include/vector Thu Sep 5 06:50:28 2019
@@ -948,8 +948,7 @@ void
vector<_Tp, _Allocator>::__swap_out_circular_buffer(__split_buffer<value_type, allocator_type&>& __v)
{
__annotate_delete();
- __alloc_traits::__construct_backward_with_exception_guarantees(
- this->__alloc(), this->__begin_, this->__end_, __v.__begin_);
+ __alloc_traits::__construct_backward(this->__alloc(), this->__begin_, this->__end_, __v.__begin_);
_VSTD::swap(this->__begin_, __v.__begin_);
_VSTD::swap(this->__end_, __v.__end_);
_VSTD::swap(this->__end_cap(), __v.__end_cap());
@@ -964,10 +963,8 @@ vector<_Tp, _Allocator>::__swap_out_circ
{
__annotate_delete();
pointer __r = __v.__begin_;
- __alloc_traits::__construct_backward_with_exception_guarantees(
- this->__alloc(), this->__begin_, __p, __v.__begin_);
- __alloc_traits::__construct_forward_with_exception_guarantees(
- this->__alloc(), __p, this->__end_, __v.__end_);
+ __alloc_traits::__construct_backward(this->__alloc(), this->__begin_, __p, __v.__begin_);
+ __alloc_traits::__construct_forward(this->__alloc(), __p, this->__end_, __v.__end_);
_VSTD::swap(this->__begin_, __v.__begin_);
_VSTD::swap(this->__end_, __v.__end_);
_VSTD::swap(this->__end_cap(), __v.__end_cap());
Removed: libcxx/trunk/test/libcxx/containers/sequences/vector/exception_safety_exceptions_disabled.sh.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/libcxx/containers/sequences/vector/exception_safety_exceptions_disabled.sh.cpp?rev=371067&view=auto
==============================================================================
--- libcxx/trunk/test/libcxx/containers/sequences/vector/exception_safety_exceptions_disabled.sh.cpp (original)
+++ libcxx/trunk/test/libcxx/containers/sequences/vector/exception_safety_exceptions_disabled.sh.cpp (removed)
@@ -1,57 +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
-//
-//===----------------------------------------------------------------------===//
-
-// RUN: %build -fno-exceptions
-// RUN: %run
-
-// UNSUPPORTED: c++98, c++03
-
-// <vector>
-
-// Test that vector always moves elements when exceptions are disabled.
-// vector is allowed to move or copy elements while resizing, so long as
-// it still provides the strong exception safety guarantee.
-
-#include <vector>
-#include <cassert>
-
-#include "test_macros.h"
-
-#ifndef TEST_HAS_NO_EXCEPTIONS
-#error exceptions should be disabled.
-#endif
-
-bool allow_moves = false;
-
-class A {
-public:
- A() {}
- A(A&&) { assert(allow_moves); }
- explicit A(int) {}
- A(A const&) { assert(false); }
-};
-
-int main(int, char**) {
- std::vector<A> v;
-
- // Create a vector containing some number of elements that will
- // have to be moved when it is resized.
- v.reserve(10);
- size_t old_cap = v.capacity();
- for (int i = 0; i < v.capacity(); ++i) {
- v.emplace_back(42);
- }
- assert(v.capacity() == old_cap);
- assert(v.size() == v.capacity());
-
- // The next emplace back should resize.
- allow_moves = true;
- v.emplace_back(42);
-
- return 0;
-}
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