https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103086
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-10 branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:5400112aa94163b1e94404e74b3000779d24303b commit r10-10374-g5400112aa94163b1e94404e74b3000779d24303b Author: Jonathan Wakely <jwak...@redhat.com> Date: Thu Nov 4 22:50:02 2021 +0000 libstdc++: Fix pretty printing of std::unique_ptr [PR103086] Since std::tuple started using [[no_unique_address]] the tuple<T*, D> member of std::unique_ptr<T, D> has two _M_head_impl subobjects, in different base classes. That means this printer code is ambiguous: tuple_head_type = tuple_impl_type.fields()[1].type # _Head_base head_field = tuple_head_type.fields()[0] if head_field.name == '_M_head_impl': self.pointer = tuple_member['_M_head_impl'] In older versions of GDB it happened to work by chance, because GDB returned the last _M_head_impl member and std::tuple's base classes are stored in reverse order, so the last one was the T* element of the tuple. Since GDB 11 it returns the first _M_head_impl, which is the deleter element. The fix is for the printer to stop using an ambiguous field name and cast the tuple to the correct base class before accessing the _M_head_impl member. Instead of fixing this in both UniquePointerPrinter and StdPathPrinter a new unique_ptr_get function is defined to do it correctly. That is defined in terms of new tuple_get and _tuple_impl_get functions. It would be possible to reuse _tuple_impl_get to access each element in StdTuplePrinter._iterator.__next__, but that already does the correct casting, and wouldn't be much simpler anyway. libstdc++-v3/ChangeLog: PR libstdc++/103086 * python/libstdcxx/v6/printers.py (_tuple_impl_get): New helper for accessing the tuple element stored in a _Tuple_impl node. (tuple_get): New function for accessing a tuple element. (unique_ptr_get): New function for accessing a unique_ptr. (UniquePointerPrinter, StdPathPrinter): Use unique_ptr_get. * python/libstdcxx/v6/xmethods.py (UniquePtrGetWorker): Cast tuple to its base class before accessing _M_head_impl. (cherry picked from commit a634928f5c8a281442ac8f5fb1636aed048ed72c)
