This makes constexpr std::vector (mostly) work in Debug Mode. All safe
iterator instrumentation and checking is disabled during constant
evaluation, because it requires mutex locks and calls to non-inline
functions defined in libstdc++.so. It should be OK to disable the safety
checks, because most UB should be detected during constant evaluation
anyway.
We could try to enable the full checking in constexpr, but it would mean
wrapping all the non-inline functions like _M_attach with an inline
_M_constexpr_attach that does the iterator housekeeping inline without
mutex locks when called for constant evaluation, and calls the
non-inline function at runtime. That could be done in future if we find
that we've lost safety or useful checking by disabling the safe
iterators.
There are a few test failures in C++20 mode, which I'm unable to
explain. The _Safe_iterator::operator++() member gives errors for using
non-constexpr functions during constant evaluation, even though those
functions are guarded by std::is_constant_evaluated() checks. The same
code works fine for C++23 and up.
libstdc++-v3/ChangeLog:
PR libstdc++/109536
* include/bits/c++config (__glibcxx_constexpr_assert): Remove
macro.
* include/bits/stl_algobase.h (__niter_base, __copy_move_a)
(__copy_move_backward_a, __fill_a, __fill_n_a, __equal_aux)
(__lexicographical_compare_aux): Add constexpr to overloads for
debug mode iterators.
* include/debug/helper_functions.h (__unsafe): Add constexpr.
* include/debug/macros.h (_GLIBCXX_DEBUG_VERIFY_COND_AT): Remove
macro, folding it into ...
(_GLIBCXX_DEBUG_VERIFY_AT_F): ... here. Do not use
__glibcxx_constexpr_assert.
* include/debug/safe_base.h (_Safe_iterator_base): Add constexpr
to some member functions. Omit attaching, detaching and checking
operations during constant evaluation.
* include/debug/safe_container.h (_Safe_container): Likewise.
* include/debug/safe_iterator.h (_Safe_iterator): Likewise.
* include/debug/safe_iterator.tcc (__niter_base, __copy_move_a)
(__copy_move_backward_a, __fill_a, __fill_n_a, __equal_aux)
(__lexicographical_compare_aux): Add constexpr.
* include/debug/vector (_Safe_vector, vector): Add constexpr.
Omit safe iterator operations during constant evaluation.
* testsuite/23_containers/vector/bool/capacity/constexpr.cc:
Remove dg-xfail-if for debug mode.
* testsuite/23_containers/vector/bool/cmp_c++20.cc: Likewise.
* testsuite/23_containers/vector/bool/cons/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/bool/element_access/1.cc:
Likewise.
* testsuite/23_containers/vector/bool/element_access/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/bool/modifiers/assign/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/bool/modifiers/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/bool/modifiers/swap/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/capacity/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/cmp_c++20.cc: Likewise.
* testsuite/23_containers/vector/cons/constexpr.cc: Likewise.
* testsuite/23_containers/vector/data_access/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/element_access/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/modifiers/assign/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/modifiers/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/modifiers/swap/constexpr.cc:
Likewise.
* testsuite/23_containers/vector/cons/destructible_debug_neg.cc:
Adjust dg-error line number.
Add testsuite/testsuite_string.h header to help testing __gnu_debug::basic_string like
std::basic_string depending on _GLIBCXX_DEBUG.
Add using of base type methods in __gnu_debug::basic_string to make use of the method
overloads when there is no debug version.
Fix _GLIBCXX_DEBUG_PEDANTIC assertions in <debug/string>. This header has to be used directly
like __gnu_debug::string, it is not included by _GLIBCXX_DEBUG. It means that
_GLIBCXX_DEBUG_PEDANTIC is not considered to define __glibcxx_check_string and
__glibcxx_check_string_len which are then empty macros. Now those macros are defined
directly in <debug/string> and properly consider _GLIBCXX_DEBUG_PEDANTIC.
libstdc++-v3/ChangeLog:
* include/debug/debug.h [_GLIBCXX_DEBUG](__glibcxx_requires_string): Define
using _GLIBCXX_DEBUG_PEDASSERT.
[_GLIBCXX_DEBUG](__glibcxx_requires_string_len): Likewise.
* include/debug/macros.h
(__glibcxx_check_string, __glibcxx_check_string_len): Move...
* include/debug/string
(__glibcxx_check_string, __glibcxx_check_string_len): ...here. And define depending
on _GLIBCXX_DEBUG_PEDANTIC no matter if _GLIBCXX_DEBUG is defined.
Add using of std::string find, rfind, find_first_of, find_last_of, find_first_not_of
and find_last_not_of. Remove debug implementations having no debug assertion.
* testsuite/util/testsuite_string.h: New file. Provides __gnu_test::string and
__gnu_test::wtring which definition depends on _GLIBCXX_DEBUG.
* testsuite/21_strings/basic_string/debug/find1_neg.cc: New test case.
* testsuite/21_strings/basic_string/debug/find2_neg.cc: New test case.
* testsuite/21_strings/basic_string/operations/find/char/1.cc:
Include <testsuite_string.h> and use __gnu_test::string.
* testsuite/21_strings/basic_string/operations/find/char/2.cc: Likewise.
* testsuite/21_strings/basic_string/operations/find/char/3.cc: Likewise.
* testsuite/21_strings/basic_string/operations/find/char/4.cc: Likewise.
* testsuite/21_strings/basic_string/operations/find/char/5.cc: Likewise.
* testsuite/21_strings/basic_string/operations/find/char/6.cc: Likewise.
* testsuite/21_strings/basic_string/operations/find/wchar_t/1.cc:
Include <testsuite_string.h> and use __gnu_test::wstring.
* testsuite/21_strings/basic_string/operations/find/wchar_t/2.cc: Likewise.
* testsuite/21_strings/basic_string/operations/find/wchar_t/3.cc: Likewise.
* testsuite/21_strings/basic_string/operations/find/wchar_t/4.cc: Likewise.
* testsuite/21_strings/basic_string/operations/find/wchar_t/5.cc: Likewise.
* testsuite/21_strings/basic_string/operations/find/wchar_t/6.cc: Likewise.
The current implementation of compile-time precondition checks causes
compilation to fail by calling a non-constexpr function declared at
block scope. This breaks the CUDA compiler, which wraps some libstdc++
headers in a pragma that declares everything as a __host__ __device__
function, but others are not wrapped and so everything is a __host__
function. The local declaration thus gets redeclared as two different
types of function, which doesn't work.
Just use __builtin_unreachable to make constant evaluation fail, instead
of the local function declaration. Also simplify the assertion macros,
which has the side effect of giving simpler compilation errors when
using Clang.
libstdc++-v3/ChangeLog:
PR libstdc++/100676
* include/bits/c++config (__glibcxx_assert_1): Rename to ...
(__glibcxx_constexpr_assert): ... this.
(__glibcxx_assert_impl): Use __glibcxx_constexpr_assert.
(__glibcxx_assert): Define as either __glibcxx_constexpr_assert
or __glibcxx_assert_impl.
(__glibcxx_assert_2): Remove
* include/debug/macros.h (_GLIBCXX_DEBUG_VERIFY_AT_F): Use
__glibcxx_constexpr_assert instead of __glibcxx_assert_1.
* testsuite/21_strings/basic_string_view/element_access/char/back_constexpr_neg.cc:
Adjust expected error.
* testsuite/21_strings/basic_string_view/element_access/char/constexpr_neg.cc:
Likewise.
* testsuite/21_strings/basic_string_view/element_access/char/front_constexpr_neg.cc:
Likewise.
Likewise.
* testsuite/21_strings/basic_string_view/element_access/wchar_t/back_constexpr_neg.cc:
Likewise.
* testsuite/21_strings/basic_string_view/element_access/wchar_t/constexpr_neg.cc:
Likewise.
* testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc:
Likewise.
* testsuite/23_containers/span/back_neg.cc: Likewise.
* testsuite/23_containers/span/front_neg.cc: Likewise.
* testsuite/23_containers/span/index_op_neg.cc: Likewise.
__dp_sign precision indicates that we found out what iterator comes first or
last in the range. __dp_sign_max_size is the same plus it gives the information
of the max size of the range that is to say the max_size value such that
distance(lhs, rhs) < max_size.
Thanks to this additional information we are able to tell when a copy of n elements
to that range will fail even if we do not know exactly how large it is.
This patch makes sure that we are properly using this information.
libstdc++-v3/ChangeLog:
PR libstdc++/99402
* include/debug/helper_functions.h (__can_advance(_InputIterator,
const std::pair<_Diff, _Distance_precision>&, int)): New.
(__can_advance(const _Safe_iterator<>&,
const std::pair<_Diff, _Distance_precision>&, int)): New.
* include/debug/macros.h (__glibcxx_check_can_increment_dist): New,
use latter.
(__glibcxx_check_can_increment_range): Adapt to use latter.
(__glibcxx_check_can_decrement_range): Likewise.
* include/debug/safe_iterator.h
(_Safe_iterator<>::_M_can_advance(const std::pair<_Diff, _Distance_precision>&,
int)): New.
(__can_advance(const _Safe_iterator<>&,
const std::pair<_Diff, _Distance_precision>&, int)): New.
* include/debug/safe_iterator.tcc
(_Safe_iterator<>::_M_can_advance(const std::pair<_Diff, _Distance_precision>&,
int)): New.
(_Safe_iterator<>::_M_valid_range(const _Safe_iterator<>&,
std::pair<difference_type, _Distance_precision>&, bool)): Adapt for
__dp_sign_max_size.
(__copy_move_a): Adapt to use __glibcxx_check_can_increment_dist.
(__copy_move_backward_a): Likewise.
(__equal_aux): Likewise.
* include/debug/stl_iterator.h (__can_advance(const std::reverse_iterator<>&,
const std::pair<_Diff, _Distance_precision>&, int)): New.
(__can_advance(const std::move_iterator<>&,
const std::pair<_Diff, _Distance_precision>&, int)): New.
* testsuite/25_algorithms/copy/debug/99402.cc: New test.
The __glibcxx_check_can_[increment|decrement]_range macros are using the
_GLIBCXX_DEBUG_VERIFY_COND_AT macro which is not constexpr compliant and will produce nasty
diagnostics rather than the std::__failed_assertion dedicated to constexpr. Replace it with
correct _GLIBCXX_DEBUG_VERIFY_AT_F.
libstdc++-v3/ChangeLog:
* include/debug/macros.h (__glibcxx_check_can_increment_range): Replace
_GLIBCXX_DEBUG_VERIFY_COND_AT usage with _GLIBCXX_DEBUG_VERIFY_AT_F.
(__glibcxx_check_can_decrement_range): Likewise.
* testsuite/25_algorithms/copy_backward/constexpr.cc (test03): New.
* testsuite/25_algorithms/copy/debug/constexpr_neg.cc: New test.
* testsuite/25_algorithms/copy_backward/debug/constexpr_neg.cc: New test.
* testsuite/25_algorithms/equal/constexpr_neg.cc: New test.
* testsuite/25_algorithms/equal/debug/constexpr_neg.cc: New test.
libstdc++-v3/ChangeLog:
* include/debug/assertions.h (__glibcxx_requires_non_empty_range):
Remove __builtin_expect.
(__glibcxx_requires_subscript): Likewise.
(__glibcxx_requires_nonempty): Likewise.
* include/debug/formatter.h (__check_singular): Add C++11 constexpr
qualification.
* include/debug/helper_functions.h (__check_singular): Likewise. Skip
check if constant evaluated.
(__valid_range): Do not skip check if constant evaluated.
* include/debug/macros.h (_GLIBCXX_DEBUG_VERIFY_COND_AT): Add
__builtin_expect.
(_GLIBCXX_DEBUG_VERIFY_AT_F): Use __glibcxx_assert_1.
* testsuite/21_strings/basic_string_view/element_access/char/back_constexpr_neg.cc:
New test.
* testsuite/21_strings/basic_string_view/element_access/char/constexpr.cc: New test.
* testsuite/21_strings/basic_string_view/element_access/char/constexpr_neg.cc: New test.
* testsuite/21_strings/basic_string_view/element_access/char/front_back_constexpr.cc:
New test.
* testsuite/21_strings/basic_string_view/element_access/char/front_constexpr_neg.cc:
New test.
* testsuite/21_strings/basic_string_view/element_access/wchar_t/back_constexpr_neg.cc:
New test.
* testsuite/21_strings/basic_string_view/element_access/wchar_t/constexpr.cc: New test.
* testsuite/21_strings/basic_string_view/element_access/wchar_t/constexpr_neg.cc: New test.
* testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc:
New test.
* testsuite/25_algorithms/lower_bound/debug/constexpr_partitioned_neg.cc: New test.
* testsuite/25_algorithms/lower_bound/debug/constexpr_partitioned_pred_neg.cc: New test.
* testsuite/25_algorithms/lower_bound/debug/constexpr_valid_range_neg.cc: New test.
* testsuite/25_algorithms/lower_bound/debug/partitioned_neg.cc: New test.
* testsuite/25_algorithms/lower_bound/debug/partitioned_pred_neg.cc: New test.
* testsuite/25_algorithms/upper_bound/debug/constexpr_partitioned_neg.cc: New test.
* testsuite/25_algorithms/upper_bound/debug/constexpr_partitioned_pred_neg.cc: New test.
* testsuite/25_algorithms/upper_bound/debug/constexpr_valid_range_neg.cc: New test.
* testsuite/25_algorithms/upper_bound/debug/partitioned_neg.cc: New test.
* testsuite/25_algorithms/upper_bound/debug/partitioned_pred_neg.cc: New test.
The C++ LWG recently confirmed that self-move assignment should not have
undefined behaviour for standard containers (see the proposed resolution
of LWG 2839). The result should be a valid but unspecified value, just
like other times when a container is moved from.
Our std::list, std::__cxx11::basic_string and unordered containers all
have bugs which result in undefined behaviour.
For std::list the problem is that we clear the previous contents using
_M_clear() instead of clear(). This means the _M_next, _M_prev and
_M_size members are not zeroed, and so after we "update" them (with
their existing values), we are left with dangling pointers and a
non-zero size, but no elements.
For the unordered containers the problem is similar. _Hashtable first
deallocates the existing contents, then takes ownership of the pointers
from the RHS object (which has just had its contents deallocated so the
pointers are dangling).
For std::basic_string it's a little more subtle. When the string is
local (i.e. fits in the SSO buffer) we use char_traits::copy to copy the
contents from this->data() to __rhs.data(). When &__rhs == this that
copy violates the precondition that the ranges don't overlap. We only
need to check for self-move for this case where it's local, because the
only other case that can be true for self-move is that it's non-local
but the allocators compare equal. In that case the data pointer is
neither deallocated nor leaked, so the result is well-defined.
This patch also makes a small optimization for std::deque move
assignment, to use the efficient move when is_always_equal is false, but
the allocators compare equal at runtime.
Finally, we need to remove all the Debug Mode checks which abort the
program when a self-move is detected, because it's not undefined to do
that.
Before PR 85828 can be closed we should also look into fixing
std::shuffle so it doesn't do any redundant self-swaps.
libstdc++-v3/ChangeLog:
PR libstdc++/85828
* include/bits/basic_string.h (operator=(basic_string&&)): Check
for self-move before copying with char_traits::copy.
* include/bits/hashtable.h (operator=(_Hashtable&&)): Check for
self-move.
* include/bits/stl_deque.h (_M_move_assign1(deque&&, false_type)):
Check for equal allocators.
* include/bits/stl_list.h (_M_move_assign(list&&, true_type)):
Call clear() instead of _M_clear().
* include/debug/formatter.h (__msg_self_move_assign): Change
comment.
* include/debug/macros.h (__glibcxx_check_self_move_assign):
(_GLIBCXX_DEBUG_VERIFY): Remove.
* include/debug/safe_container.h (operator=(_Safe_container&&)):
Remove assertion check for safe move and make it well-defined.
* include/debug/safe_iterator.h (operator=(_Safe_iterator&&)):
Remove assertion check for self-move.
* include/debug/safe_local_iterator.h
(operator=(_Safe_local_iterator&&)): Likewise.
* testsuite/21_strings/basic_string/cons/char/self_move.cc: New test.
* testsuite/23_containers/deque/cons/self_move.cc: New test.
* testsuite/23_containers/forward_list/cons/self_move.cc: New test.
* testsuite/23_containers/list/cons/self_move.cc: New test.
* testsuite/23_containers/set/cons/self_move.cc: New test.
* testsuite/23_containers/unordered_set/cons/self_move.cc: New test.
* testsuite/23_containers/vector/cons/self_move.cc: New test.
2013-08-01 François Dumont <fdumont@gcc.gnu.org>
PR libstdc++/57779
* include/debug/formatter.h (_Debug_msg_id): Add
__msg_insert_itself_range entry.
* include/debug/functions.h (_Insert_range_from_self_is_safe<>):
New, indicate container types supporting self range insertion in
GNU implementation.
(__foreign_iterator): New, check if an iterator points to a given
sequence.
* include/debug/macros.h (__glibcxx_check_insert_range): Add check
using __foreign_iterator.
(__gibcxx_check_insert_range_after): Likewise.
* include/debug/string (_Insert_range_from_self_is_safe<>):
Partially specialized to mark __gnu_debug::basic_string<> as
supporting self range insert.
* include/debug/list (_Insert_range_from_self_is_safe<>):
Partially specialized to mark std::list as supporting self range
insert if _GLIBCXX_DEBUG_PEDANTIC is not defined.
* include/debug/forward_list (_Insert_range_from_self_is_safe<>):
Likewise.
* src/c++11/debug.cc (_S_debug_messages): Add
__msg_insert_itself_range_entry message.
(_Error_formatter::_Parameter::_M_print_description): Display
iterator sequence address rather than sequence address when the
parameter type is an iterator.
(_Error_formatter::_M_print_word): Enhance behavior when
displaying a word with an appended '\n'.
* testsuite/util/debug/checks.h (check_insert4<>): New.
* testsuite/23_containers/deque/debug/insert5_neg.cc: New.
* testsuite/23_containers/vector/debug/insert5_neg.cc: Likewise.
* testsuite/23_containers/vector/debug/insert6_neg.cc: Likewise.
* testsuite/23_containers/vector/debug/57779_neg.cc: Likewise.
* testsuite/23_containers/list/debug/insert5_neg.cc: Likewise.
* testsuite/23_containers/forward_list/debug/insert_after4_neg.cc:
Likewise.
From-SVN: r201416
2012-05-11 François Dumont <fdumont@gcc.gnu.org>
PR libstdc++/53263
* include/debug/safe_iterator.h (__gnu_debug::__base): Move...
* include/debug/functions.h: ... Here. Add debug function
overloads to perform checks on normal iterators when possible.
* include/debug/macros.h (__glibcxx_check_heap)
(__glibcxx_check_heap_pred): Use __gnu_debug::__base on iterator range.
From-SVN: r187414
2009-06-23 Jonathan Wakely <jwakely.gcc@gmail.com>
* include/debug/macros.h: Replace @tbd with valid doxygen tag @todo.
* include/std/ratio: Typo in comment.
From-SVN: r148861
Jakub Jelinek