diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index dbf1a8865f6..c7b20f10dc5 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,12 @@
+2019-05-18  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/90520
+	* python/libstdcxx/v6/printers.py (UniquePointerPrinter.__init__):
+	Raise exception if unique_ptr tuple member has unknown structure.
+	* python/libstdcxx/v6/xmethods.py (UniquePtrGetWorker.__call__):
+	Adjust worker to support new __uniq_ptr_data base class. Do not
+	assume field called _M_head_impl is the first tuple element.
+
 2019-05-17  François Dumont  <fdumont@gcc.gnu.org>
 
 	* include/bits/stl_deque.h
diff --git a/libstdc++-v3/python/libstdcxx/v6/printers.py b/libstdc++-v3/python/libstdcxx/v6/printers.py
index 162b00760e6..05143153bee 100644
--- a/libstdc++-v3/python/libstdcxx/v6/printers.py
+++ b/libstdc++-v3/python/libstdcxx/v6/printers.py
@@ -197,6 +197,8 @@ class UniquePointerPrinter:
             self.pointer = tuple_member['_M_head_impl']
         elif head_field.is_base_class:
             self.pointer = tuple_member.cast(head_field.type)
+        else:
+            raise ValueError("Unsupported implementation for tuple in unique_ptr: %s" % impl_type)
 
     def children (self):
         return SmartPtrIterator(self.pointer)
diff --git a/libstdc++-v3/python/libstdcxx/v6/xmethods.py b/libstdc++-v3/python/libstdcxx/v6/xmethods.py
index c405d8a25d5..623cb80bc0e 100644
--- a/libstdc++-v3/python/libstdcxx/v6/xmethods.py
+++ b/libstdc++-v3/python/libstdcxx/v6/xmethods.py
@@ -586,11 +586,22 @@ class UniquePtrGetWorker(gdb.xmethod.XMethodWorker):
 
     def __call__(self, obj):
         impl_type = obj.dereference().type.fields()[0].type.tag
-        if re.match('^std::(__\d+::)?__uniq_ptr_impl<.*>$', impl_type): # New implementation
-            return obj['_M_t']['_M_t']['_M_head_impl']
+        # Check for new implementations first:
+        if re.match('^std::(__\d+::)?__uniq_ptr_(data|impl)<.*>$', impl_type):
+            tuple_member = obj['_M_t']['_M_t']
         elif re.match('^std::(__\d+::)?tuple<.*>$', impl_type):
-            return obj['_M_t']['_M_head_impl']
-        return None
+            tuple_member = obj['_M_t']
+        else:
+            return None
+        tuple_impl_type = tuple_member.type.fields()[0].type # _Tuple_impl
+        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':
+            return tuple_member['_M_head_impl']
+        elif head_field.is_base_class:
+            return tuple_member.cast(head_field.type)
+        else:
+            return None
 
 class UniquePtrDerefWorker(UniquePtrGetWorker):
     "Implements std::unique_ptr<T>::operator*()"