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[libc++] Audit all uses of _LIBCPP_ASSERT and _LIBCPP_DEBUG_ASSERT
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I audited all uses of _LIBCPP_ASSERT to make sure that we only used it
for "basic assertions", i.e. assertions with constant-time conditions.
I also audited all uses of _LIBCPP_DEBUG_ASSERT to make sure we used it
only for debug-mode assertions, and in one case had to change for
_LIBCPP_ASSERT instead.

As a fly-by, I also changed a couple of tests against nullptr or 0 to
be more explicit.

After this patch, all uses of _LIBCPP_ASSERT should be with constant-time
conditions, and all uses of _LIBCPP_DEBUG_ASSERT should be with conditions
that we only want to check when the debug mode is enabled.

Differential Revision: https://reviews.llvm.org/D122395
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@ldionne
ldionne committed Mar 24, 2022
1 parent aca9648 commit c87c891
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Showing 5 changed files with 43 additions and 52 deletions.
4 changes: 2 additions & 2 deletions libcxx/include/__hash_table
View file
Expand Up @@ -2478,8 +2478,8 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p)
_LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
"unordered container erase(iterator) called with an iterator not"
" referring to this container");
_LIBCPP_DEBUG_ASSERT(__p != end(),
"unordered container erase(iterator) called with a non-dereferenceable iterator");
_LIBCPP_ASSERT(__p != end(),
"unordered container erase(iterator) called with a non-dereferenceable iterator");
#if _LIBCPP_DEBUG_LEVEL == 2
iterator __r(__np, this);
#else
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6 changes: 3 additions & 3 deletions libcxx/include/__memory/construct_at.h
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Expand Up @@ -34,7 +34,7 @@ template<class _Tp, class ..._Args, class = decltype(
)>
_LIBCPP_HIDE_FROM_ABI
constexpr _Tp* construct_at(_Tp* __location, _Args&& ...__args) {
_LIBCPP_ASSERT(__location, "null pointer given to construct_at");
_LIBCPP_ASSERT(__location != nullptr, "null pointer given to construct_at");
return ::new (_VSTD::__voidify(*__location)) _Tp(_VSTD::forward<_Args>(__args)...);
}

Expand All @@ -52,15 +52,15 @@ _ForwardIterator __destroy(_ForwardIterator, _ForwardIterator);
template <class _Tp, typename enable_if<!is_array<_Tp>::value, int>::type = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
void __destroy_at(_Tp* __loc) {
_LIBCPP_ASSERT(__loc, "null pointer given to destroy_at");
_LIBCPP_ASSERT(__loc != nullptr, "null pointer given to destroy_at");
__loc->~_Tp();
}

#if _LIBCPP_STD_VER > 17
template <class _Tp, typename enable_if<is_array<_Tp>::value, int>::type = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
void __destroy_at(_Tp* __loc) {
_LIBCPP_ASSERT(__loc, "null pointer given to destroy_at");
_LIBCPP_ASSERT(__loc != nullptr, "null pointer given to destroy_at");
_VSTD::__destroy(_VSTD::begin(*__loc), _VSTD::end(*__loc));
}
#endif
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23 changes: 14 additions & 9 deletions libcxx/include/list
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Expand Up @@ -2020,6 +2020,17 @@ list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __i)
}
}

template <class _Iterator>
_LIBCPP_HIDE_FROM_ABI
bool __iterator_in_range(_Iterator __first, _Iterator __last, _Iterator __it) {
for (_Iterator __p = __first; __p != __last; ++__p) {
if (__p == __it) {
return true;
}
}
return false;
}

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l)
Expand All @@ -2030,16 +2041,10 @@ list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __f, con
"list::splice(iterator, list, iterator, iterator) called with second iterator not referring to the list argument");
_LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__l)) == _VSTD::addressof(__c),
"list::splice(iterator, list, iterator, iterator) called with third iterator not referring to the list argument");
_LIBCPP_DEBUG_ASSERT(this != std::addressof(__c) || !std::__iterator_in_range(__f, __l, __p),
"list::splice(iterator, list, iterator, iterator)"
" called with the first iterator within the range of the second and third iterators");

#if _LIBCPP_DEBUG_LEVEL == 2
if (this == _VSTD::addressof(__c))
{
for (const_iterator __i = __f; __i != __l; ++__i)
_LIBCPP_DEBUG_ASSERT(__i != __p,
"list::splice(iterator, list, iterator, iterator)"
" called with the first iterator within the range of the second and third iterators");
}
#endif
if (__f != __l)
{
__link_pointer __first = __f.__ptr_;
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60 changes: 23 additions & 37 deletions libcxx/include/unordered_set
View file
Expand Up @@ -639,36 +639,27 @@ public:
pair<iterator, bool> emplace(_Args&&... __args)
{return __table_.__emplace_unique(_VSTD::forward<_Args>(__args)...);}
template <class... _Args>
_LIBCPP_INLINE_VISIBILITY
#if _LIBCPP_DEBUG_LEVEL == 2
iterator emplace_hint(const_iterator __p, _Args&&... __args)
{
_LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
"unordered_set::emplace_hint(const_iterator, args...) called with an iterator not"
" referring to this unordered_set");
return __table_.__emplace_unique(_VSTD::forward<_Args>(__args)...).first;
}
#else
iterator emplace_hint(const_iterator, _Args&&... __args)
{return __table_.__emplace_unique(_VSTD::forward<_Args>(__args)...).first;}
#endif
_LIBCPP_INLINE_VISIBILITY
iterator emplace_hint(const_iterator __p, _Args&&... __args) {
_LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(std::addressof(__p)) == this,
"unordered_set::emplace_hint(const_iterator, args...) called with an iterator not"
" referring to this unordered_set");
(void)__p;
return __table_.__emplace_unique(std::forward<_Args>(__args)...).first;
}

_LIBCPP_INLINE_VISIBILITY
pair<iterator, bool> insert(value_type&& __x)
{return __table_.__insert_unique(_VSTD::move(__x));}
_LIBCPP_INLINE_VISIBILITY
#if _LIBCPP_DEBUG_LEVEL == 2
iterator insert(const_iterator __p, value_type&& __x)
{
_LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
"unordered_set::insert(const_iterator, value_type&&) called with an iterator not"
" referring to this unordered_set");
return insert(_VSTD::move(__x)).first;
}
#else
iterator insert(const_iterator, value_type&& __x)
{return insert(_VSTD::move(__x)).first;}
#endif
iterator insert(const_iterator __p, value_type&& __x) {
_LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(std::addressof(__p)) == this,
"unordered_set::insert(const_iterator, value_type&&) called with an iterator not"
" referring to this unordered_set");
(void)__p;
return insert(std::move(__x)).first;
}

_LIBCPP_INLINE_VISIBILITY
void insert(initializer_list<value_type> __il)
{insert(__il.begin(), __il.end());}
Expand All @@ -678,18 +669,13 @@ public:
{return __table_.__insert_unique(__x);}

_LIBCPP_INLINE_VISIBILITY
#if _LIBCPP_DEBUG_LEVEL == 2
iterator insert(const_iterator __p, const value_type& __x)
{
_LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
"unordered_set::insert(const_iterator, const value_type&) called with an iterator not"
" referring to this unordered_set");
return insert(__x).first;
}
#else
iterator insert(const_iterator, const value_type& __x)
{return insert(__x).first;}
#endif
iterator insert(const_iterator __p, const value_type& __x) {
_LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(std::addressof(__p)) == this,
"unordered_set::insert(const_iterator, const value_type&) called with an iterator not"
" referring to this unordered_set");
(void)__p;
return insert(__x).first;
}
template <class _InputIterator>
_LIBCPP_INLINE_VISIBILITY
void insert(_InputIterator __first, _InputIterator __last);
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2 changes: 1 addition & 1 deletion libcxx/src/filesystem/filesystem_common.h
View file
Expand Up @@ -111,7 +111,7 @@ format_string(const char* msg, ...) {
}

error_code capture_errno() {
_LIBCPP_ASSERT(errno, "Expected errno to be non-zero");
_LIBCPP_ASSERT(errno != 0, "Expected errno to be non-zero");
return error_code(errno, generic_category());
}

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