[Bug libstdc++/91997] pretty printers: The __node_type type alias in _Hashtable is not available

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91997

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:

https://gcc.gnu.org/g:b1dba8a228e7d9497d2ddbd012b4343f99b87823

commit r9-9168-gb1dba8a228e7d9497d2ddbd012b4343f99b87823
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Nov 29 14:47:03 2019 +0000

    libstdc++: improve how pretty printers find node types (PR 91997)

    This fixes two related problems.

    The iterators for node-based containers use nested typedefs such as
    std::list<T>::iterator::_Node to denote their node types. As reported in
    https://bugzilla.redhat.com/show_bug.cgi?id=1053438 those typedefs are
    not always present in the debug info. That means the pretty printers
    cannot find them using gdb.lookup_type (via the find_type helper).
    Instead of looking up the nested typedefs this patch makes the printers
    look up the actual class templates directly.

    A related problem (and the original topic of PR 91997) is that GDB fails
    to find types via gdb.lookup_type when printing a backtrace from a
    non-C++ functiion: https://sourceware.org/bugzilla/show_bug.cgi?id=25234
    That is also solved by not looking up the nested typedef.

            PR libstdc++/91997
            * python/libstdcxx/v6/printers.py (find_type): Fail more gracefully
            if we run out of base classes to look at.
            (llokup_templ_spec, lookup_node_type): New utilities to find node
            types for node-based containers.
            (StdListPrinter.children, NodeIteratorPrinter.__init__)
            (NodeIteratorPrinter.to_string, StdSlistPrinter.children)
            (StdSlistIteratorPrinter.to_string,
StdRbtreeIteratorPrinter.__init__)
            (StdMapPrinter.children, StdSetPrinter.children)
            (StdForwardListPrinter.children): Use lookup_node_type instead of
            find_type.
            (StdListIteratorPrinter.__init__,
StdFwdListIteratorPrinter.__init__):
            Pass name of node type to NodeIteratorPrinter constructor.
            (Tr1HashtableIterator.__init__): Rename argument.
            (StdHashtableIterator.__init__): Likewise. Use lookup_templ_spec
            instead of find_type.
            * testsuite/libstdc++-prettyprinters/59161.cc: Remove workaround
for
            _Node typedef not being present in debuginfo.
            * testsuite/libstdc++-prettyprinters/91997.cc: New test.

    (cherry picked from commit 9d50a6a78509b42b3c2b2264da1a0d2c4b151d66)