Currently dereferencing an empty shared_ptr prints a complicated
internal type in the assertion message:
include/bits/shared_ptr_base.h:1377: std::__shared_ptr_access<_Tp, _Lp,
<anonymous>, <anonymous> >::element_type& std::__shared_ptr_access<_Tp, _Lp,
<anonymous>, <anonymous> >::operator*() const [with _Tp =
std::filesystem::__cxx11::recursive_directory_iterator::_Dir_stack;
__gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic; bool <anonymous> = false;
bool <anonymous> = false; element_type =
std::filesystem::__cxx11::recursive_directory_iterator::_Dir_stack]: Assertion
'_M_get() != nullptr' failed.
Users don't care about any of the _Lp and <anonymous> template
parameters, so this is unnecessarily verbose.
We can simplify it to something that only mentions "shared_ptr_deref"
and the element type:
include/bits/shared_ptr_base.h:1371: _Tp* std::__shared_ptr_deref(_Tp*) [with
_Tp = filesystem::__cxx11::recursive_directory_iterator::_Dir_stack]: Assertion
'__p != nullptr' failed.
libstdc++-v3/ChangeLog:
* include/bits/shared_ptr_base.h (__shared_ptr_deref): New
function template.
(__shared_ptr_access, __shared_ptr_access<>): Use it.
---
Tested x86_64-linux.
Also available for review at:
https://forge.sourceware.org/gcc/gcc-TEST/pulls/13
libstdc++-v3/include/bits/shared_ptr_base.h | 28 +++++++++++++--------
1 file changed, 17 insertions(+), 11 deletions(-)
diff --git a/libstdc++-v3/include/bits/shared_ptr_base.h
b/libstdc++-v3/include/bits/shared_ptr_base.h
index 9a7617e7014..ee01594ce0c 100644
--- a/libstdc++-v3/include/bits/shared_ptr_base.h
+++ b/libstdc++-v3/include/bits/shared_ptr_base.h
@@ -1337,6 +1337,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ };
+ template<typename _Tp>
+ [[__gnu__::__always_inline__]]
+ inline _Tp*
+ __shared_ptr_deref(_Tp* __p)
+ {
+ __glibcxx_assert(__p != nullptr);
+ return __p;
+ }
+
// Define operator* and operator-> for shared_ptr<T>.
template<typename _Tp, _Lock_policy _Lp,
bool = is_array<_Tp>::value, bool = is_void<_Tp>::value>
@@ -1347,10 +1356,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
element_type&
operator*() const noexcept
- {
- __glibcxx_assert(_M_get() != nullptr);
- return *_M_get();
- }
+ { return *std::__shared_ptr_deref(_M_get()); }
element_type*
operator->() const noexcept
@@ -1392,10 +1398,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
[[__deprecated__("shared_ptr<T[]>::operator* is absent from C++17")]]
element_type&
operator*() const noexcept
- {
- __glibcxx_assert(_M_get() != nullptr);
- return *_M_get();
- }
+ { return *std::__shared_ptr_deref(_M_get()); }
[[__deprecated__("shared_ptr<T[]>::operator-> is absent from C++17")]]
element_type*
@@ -1406,13 +1409,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
#endif
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wc++17-extensions"
element_type&
operator[](ptrdiff_t __i) const noexcept
{
- __glibcxx_assert(_M_get() != nullptr);
- __glibcxx_assert(!extent<_Tp>::value || __i < extent<_Tp>::value);
- return _M_get()[__i];
+ if constexpr (extent<_Tp>::value)
+ __glibcxx_assert(__i < extent<_Tp>::value);
+ return std::__shared_ptr_deref(_M_get())[__i];
}
+#pragma GCC diagnostic pop
private:
element_type*
--
2.47.0
