[gcc r15-905] libstdc++: Use RAII to replace try/catch blocks
Francois Dumont
fdumont@gcc.gnu.org
Wed May 29 14:43:50 GMT 2024
https://gcc.gnu.org/g:d22eaeca7634b57e80ea61cadd82902fdc7e57ea
commit r15-905-gd22eaeca7634b57e80ea61cadd82902fdc7e57ea
Author: François Dumont <fdumont@gcc.gnu.org>
Date: Thu May 16 06:59:50 2024 +0200
libstdc++: Use RAII to replace try/catch blocks
Move _Guard into std::vector declaration and use it to guard all calls to
vector _M_allocate.
Doing so the compiler has more visibility on what is done with the pointers
and do not raise anymore the -Wfree-nonheap-object warning.
libstdc++-v3/ChangeLog:
* include/bits/vector.tcc (_Guard): Move all the nested duplicated class...
* include/bits/stl_vector.h (_Guard_alloc): ...here and rename.
(_M_allocate_and_copy): Use latter.
(_M_initialize_dispatch): Small code simplification.
(_M_range_initialize): Likewise and set _M_finish first from the result
of __uninitialize_fill_n_a that can throw.
Diff:
---
libstdc++-v3/include/bits/stl_vector.h | 77 ++++++++++++++++++++++-----------
libstdc++-v3/include/bits/vector.tcc | 78 ++--------------------------------
2 files changed, 55 insertions(+), 100 deletions(-)
diff --git a/libstdc++-v3/include/bits/stl_vector.h b/libstdc++-v3/include/bits/stl_vector.h
index 31169711a48..182ad41ed94 100644
--- a/libstdc++-v3/include/bits/stl_vector.h
+++ b/libstdc++-v3/include/bits/stl_vector.h
@@ -1607,6 +1607,39 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
clear() _GLIBCXX_NOEXCEPT
{ _M_erase_at_end(this->_M_impl._M_start); }
+ private:
+ // RAII guard for allocated storage.
+ struct _Guard_alloc
+ {
+ pointer _M_storage; // Storage to deallocate
+ size_type _M_len;
+ _Base& _M_vect;
+
+ _GLIBCXX20_CONSTEXPR
+ _Guard_alloc(pointer __s, size_type __l, _Base& __vect)
+ : _M_storage(__s), _M_len(__l), _M_vect(__vect)
+ { }
+
+ _GLIBCXX20_CONSTEXPR
+ ~_Guard_alloc()
+ {
+ if (_M_storage)
+ _M_vect._M_deallocate(_M_storage, _M_len);
+ }
+
+ _GLIBCXX20_CONSTEXPR
+ pointer
+ _M_release()
+ {
+ pointer __res = _M_storage;
+ _M_storage = pointer();
+ return __res;
+ }
+
+ private:
+ _Guard_alloc(const _Guard_alloc&);
+ };
+
protected:
/**
* Memory expansion handler. Uses the member allocation function to
@@ -1618,18 +1651,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
_M_allocate_and_copy(size_type __n,
_ForwardIterator __first, _ForwardIterator __last)
{
- pointer __result = this->_M_allocate(__n);
- __try
- {
- std::__uninitialized_copy_a(__first, __last, __result,
- _M_get_Tp_allocator());
- return __result;
- }
- __catch(...)
- {
- _M_deallocate(__result, __n);
- __throw_exception_again;
- }
+ _Guard_alloc __guard(this->_M_allocate(__n), __n, *this);
+ std::__uninitialized_copy_a
+ (__first, __last, __guard._M_storage, _M_get_Tp_allocator());
+ return __guard._M_release();
}
@@ -1642,13 +1667,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
// 438. Ambiguity in the "do the right thing" clause
template<typename _Integer>
void
- _M_initialize_dispatch(_Integer __n, _Integer __value, __true_type)
+ _M_initialize_dispatch(_Integer __int_n, _Integer __value, __true_type)
{
- this->_M_impl._M_start = _M_allocate(_S_check_init_len(
- static_cast<size_type>(__n), _M_get_Tp_allocator()));
- this->_M_impl._M_end_of_storage =
- this->_M_impl._M_start + static_cast<size_type>(__n);
- _M_fill_initialize(static_cast<size_type>(__n), __value);
+ const size_type __n = static_cast<size_type>(__int_n);
+ pointer __start =
+ _M_allocate(_S_check_init_len(__n, _M_get_Tp_allocator()));
+ this->_M_impl._M_start = __start;
+ this->_M_impl._M_end_of_storage = __start + __n;
+ _M_fill_initialize(__n, __value);
}
// Called by the range constructor to implement [23.1.1]/9
@@ -1690,13 +1716,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
std::forward_iterator_tag)
{
const size_type __n = std::distance(__first, __last);
- this->_M_impl._M_start
- = this->_M_allocate(_S_check_init_len(__n, _M_get_Tp_allocator()));
- this->_M_impl._M_end_of_storage = this->_M_impl._M_start + __n;
- this->_M_impl._M_finish =
- std::__uninitialized_copy_a(__first, __last,
- this->_M_impl._M_start,
- _M_get_Tp_allocator());
+ pointer __start =
+ this->_M_allocate(_S_check_init_len(__n, _M_get_Tp_allocator()));
+ _Guard_alloc __guard(__start, __n, *this);
+ this->_M_impl._M_finish = std::__uninitialized_copy_a
+ (__first, __last, __start, _M_get_Tp_allocator());
+ this->_M_impl._M_start = __start;
+ (void) __guard._M_release();
+ this->_M_impl._M_end_of_storage = __start + __n;
}
// Called by the first initialize_dispatch above and by the
diff --git a/libstdc++-v3/include/bits/vector.tcc b/libstdc++-v3/include/bits/vector.tcc
index 25df060beee..36b27dce7b9 100644
--- a/libstdc++-v3/include/bits/vector.tcc
+++ b/libstdc++-v3/include/bits/vector.tcc
@@ -467,32 +467,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
pointer __new_start(this->_M_allocate(__len));
pointer __new_finish(__new_start);
- // RAII guard for allocated storage.
- struct _Guard
{
- pointer _M_storage; // Storage to deallocate
- size_type _M_len;
- _Tp_alloc_type& _M_alloc;
-
- _GLIBCXX20_CONSTEXPR
- _Guard(pointer __s, size_type __l, _Tp_alloc_type& __a)
- : _M_storage(__s), _M_len(__l), _M_alloc(__a)
- { }
-
- _GLIBCXX20_CONSTEXPR
- ~_Guard()
- {
- if (_M_storage)
- __gnu_cxx::__alloc_traits<_Tp_alloc_type>::
- deallocate(_M_alloc, _M_storage, _M_len);
- }
-
- private:
- _Guard(const _Guard&);
- };
-
- {
- _Guard __guard(__new_start, __len, _M_impl);
+ _Guard_alloc __guard(__new_start, __len, *this);
// The order of the three operations is dictated by the C++11
// case, where the moves could alter a new element belonging
@@ -596,32 +572,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
pointer __new_start(this->_M_allocate(__len));
pointer __new_finish(__new_start);
- // RAII guard for allocated storage.
- struct _Guard
{
- pointer _M_storage; // Storage to deallocate
- size_type _M_len;
- _Tp_alloc_type& _M_alloc;
-
- _GLIBCXX20_CONSTEXPR
- _Guard(pointer __s, size_type __l, _Tp_alloc_type& __a)
- : _M_storage(__s), _M_len(__l), _M_alloc(__a)
- { }
-
- _GLIBCXX20_CONSTEXPR
- ~_Guard()
- {
- if (_M_storage)
- __gnu_cxx::__alloc_traits<_Tp_alloc_type>::
- deallocate(_M_alloc, _M_storage, _M_len);
- }
-
- private:
- _Guard(const _Guard&);
- };
-
- {
- _Guard __guard(__new_start, __len, _M_impl);
+ _Guard_alloc __guard(__new_start, __len, *this);
// The order of the three operations is dictated by the C++11
// case, where the moves could alter a new element belonging
@@ -833,32 +785,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
_M_check_len(__n, "vector::_M_default_append");
pointer __new_start(this->_M_allocate(__len));
- // RAII guard for allocated storage.
- struct _Guard
- {
- pointer _M_storage; // Storage to deallocate
- size_type _M_len;
- _Tp_alloc_type& _M_alloc;
-
- _GLIBCXX20_CONSTEXPR
- _Guard(pointer __s, size_type __l, _Tp_alloc_type& __a)
- : _M_storage(__s), _M_len(__l), _M_alloc(__a)
- { }
-
- _GLIBCXX20_CONSTEXPR
- ~_Guard()
- {
- if (_M_storage)
- __gnu_cxx::__alloc_traits<_Tp_alloc_type>::
- deallocate(_M_alloc, _M_storage, _M_len);
- }
-
- private:
- _Guard(const _Guard&);
- };
-
{
- _Guard __guard(__new_start, __len, _M_impl);
+ _Guard_alloc __guard(__new_start, __len, *this);
std::__uninitialized_default_n_a(__new_start + __size, __n,
_M_get_Tp_allocator());
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