[gcc r13-6579] libstdc++: Fix GDB Xmethod for std::shared_ptr::use_count() [PR109064]

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

https://gcc.gnu.org/g:37c8a083d44f8123ad81a3cd411389b0b7b42ae6

commit r13-6579-g37c8a083d44f8123ad81a3cd411389b0b7b42ae6
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Mar 10 11:06:25 2023 +0000

    libstdc++: Fix GDB Xmethod for std::shared_ptr::use_count() [PR109064]
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/109064
            * python/libstdcxx/v6/xmethods.py (SharedPtrUseCountWorker):
            Remove self-recursion in __init__. Add missing _supports.
            * testsuite/libstdc++-xmethods/shared_ptr.cc: Check use_count()
            and unique().

Diff:
---
 libstdc++-v3/python/libstdcxx/v6/xmethods.py            | 5 ++++-
 libstdc++-v3/testsuite/libstdc++-xmethods/shared_ptr.cc | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/python/libstdcxx/v6/xmethods.py b/libstdc++-v3/python/libstdcxx/v6/xmethods.py
index 6af7a3dcfe3..18a165f425e 100644
--- a/libstdc++-v3/python/libstdcxx/v6/xmethods.py
+++ b/libstdc++-v3/python/libstdcxx/v6/xmethods.py
@@ -730,7 +730,7 @@ class SharedPtrUseCountWorker(gdb.xmethod.XMethodWorker):
     "Implements std::shared_ptr<T>::use_count()"
 
     def __init__(self, elem_type):
-        SharedPtrUseCountWorker.__init__(self, elem_type)
+        pass
 
     def get_arg_types(self):
         return None
@@ -738,6 +738,9 @@ class SharedPtrUseCountWorker(gdb.xmethod.XMethodWorker):
     def get_result_type(self, obj):
         return gdb.lookup_type('long')
 
+    def _supports(self, method_name):
+        return True
+
     def __call__(self, obj):
         refcounts = obj['_M_refcount']['_M_pi']
         return refcounts['_M_use_count'] if refcounts else 0
diff --git a/libstdc++-v3/testsuite/libstdc++-xmethods/shared_ptr.cc b/libstdc++-v3/testsuite/libstdc++-xmethods/shared_ptr.cc
index c89f1d05aa3..c228d3ad26c 100644
--- a/libstdc++-v3/testsuite/libstdc++-xmethods/shared_ptr.cc
+++ b/libstdc++-v3/testsuite/libstdc++-xmethods/shared_ptr.cc
@@ -37,6 +37,8 @@ main ()
 
   std::shared_ptr<x_struct[3]> s(new x_struct[2]{ {92}, {115} });
 
+  auto qq = q;
+
 // { dg-final { note-test *p 10 } }
 // { dg-final { regexp-test p.get() 0x.* } }
 
@@ -67,6 +69,11 @@ main ()
 // { dg-final { whatis-test s.get() "x_struct \*" } }
 // { dg-final { whatis-test s\[1].y int } }
 
+// { dg-final { note-test p.use_count() 1 } }
+// { dg-final { note-test p.unique() true } }
+// { dg-final { note-test q.use_count() 2 } }
+// { dg-final { note-test q.unique() false } }
+
   return 0;  // Mark SPOT
 }