[gcc r9-9589] libstdc++: Fix find_type helper to work consistently

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:3f023bc5bb3d260ffe7d6e1f333fb41bbbbae444

commit r9-9589-g3f023bc5bb3d260ffe7d6e1f333fb41bbbbae444
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Mar 11 16:48:32 2021 +0000

    libstdc++: Fix find_type helper to work consistently
    
    The find_type helper function sometimes results in "class X::name" and
    lookup for that fails. For more details see "Problem 1" in
    https://gcc.gnu.org/pipermail/libstdc++/2021-March/052132.html and the
    example at https://sourceware.org/bugzilla/show_bug.cgi?id=27510#c2
    
    This patch replaces typ.unqualified() with typ.tag, which is never
    qualified, and will never include the 'class' or 'struct' keywords.
    Using the .tag attribute should be safe here because we know we are
    looking at a class type and we've already used strip_typedefs().
    
    libstdc++-v3/ChangeLog:
    
            * python/libstdcxx/v6/printers.py (find_type): Use tag attribute
            instead of unqualified() method.
    
    (cherry picked from commit 9dacc828bf8b087ddfaf797ed7238da45609082c)

Diff:
---
 libstdc++-v3/python/libstdcxx/v6/printers.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/python/libstdcxx/v6/printers.py b/libstdc++-v3/python/libstdcxx/v6/printers.py
index 32b8210414a..0c94a038437 100644
--- a/libstdc++-v3/python/libstdcxx/v6/printers.py
+++ b/libstdc++-v3/python/libstdcxx/v6/printers.py
@@ -85,8 +85,8 @@ except ImportError:
 def find_type(orig, name):
     typ = orig.strip_typedefs()
     while True:
-        # Strip cv-qualifiers.  PR 67440.
-        search = '%s::%s' % (typ.unqualified(), name)
+        # Use Type.tag to ignore cv-qualifiers.  PR 67440.
+        search = '%s::%s' % (typ.tag, name)
         try:
             return gdb.lookup_type(search)
         except RuntimeError: