[patch] fix libstdc++/59476 - pretty printers

[Jonathan Wakely <jwakely at redhat dot com>]

Update the python pretty printers to understand how _Rb_tree_node is
defined in C++11 mode now.

Tested x86_64-linux, committed to trunk and the 4.9 branch.

commit a498be0a723e8c6b60185d5c15081be4650b2644
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri May 2 14:02:51 2014 +0100

    	PR libstdc++/59476
    	* python/libstdcxx/v6/printers.py (get_value_from_Rb_tree_node): New
    	function to handle both C++03 and C++11 _Rb_tree_node implementations.
    	(StdRbtreeIteratorPrinter, StdMapPrinter, StdSetPrinter): Use it.
    	* testsuite/libstdc++-prettyprinters/simple.cc: Update comment to
    	refer to...
    	* testsuite/libstdc++-prettyprinters/simple11.cc: New.

diff --git a/libstdc++-v3/python/libstdcxx/v6/printers.py b/libstdc++-v3/python/libstdcxx/v6/printers.py
index 05da17b..1f1f860 100644
--- a/libstdc++-v3/python/libstdcxx/v6/printers.py
+++ b/libstdc++-v3/python/libstdcxx/v6/printers.py
@@ -375,6 +375,22 @@ class RbtreeIterator:
             self.node = node
         return result
 
+def get_value_from_Rb_tree_node(node):
+    """Returns the value held in an _Rb_tree_node<_Val>"""
+    try:
+        member = node.type.fields()[1].name
+        if member == '_M_value_field':
+            # C++03 implementation, node contains the value as a member
+            return node['_M_value_field']
+        elif member == '_M_storage':
+            # C++11 implementation, node stores value in __aligned_buffer
+            p = node['_M_storage']['_M_storage'].address
+            p = p.cast(node.type.template_argument(0).pointer())
+            return p.dereference()
+    except:
+        pass
+    raise ValueError, "Unsupported implementation for %s" % str(node.type)
+
 # This is a pretty printer for std::_Rb_tree_iterator (which is
 # std::map::iterator), and has nothing to do with the RbtreeIterator
 # class above.
@@ -387,7 +403,8 @@ class StdRbtreeIteratorPrinter:
     def to_string (self):
         typename = str(self.val.type.strip_typedefs()) + '::_Link_type'
         nodetype = gdb.lookup_type(typename).strip_typedefs()
-        return self.val.cast(nodetype).dereference()['_M_value_field']
+        node = self.val.cast(nodetype).dereference()
+        return get_value_from_Rb_tree_node(node)
 
 class StdDebugIteratorPrinter:
     "Print a debug enabled version of an iterator"
@@ -417,7 +434,8 @@ class StdMapPrinter:
         def next(self):
             if self.count % 2 == 0:
                 n = self.rbiter.next()
-                n = n.cast(self.type).dereference()['_M_value_field']
+                n = n.cast(self.type).dereference()
+                n = get_value_from_Rb_tree_node(n)
                 self.pair = n
                 item = n['first']
             else:
@@ -458,7 +476,8 @@ class StdSetPrinter:
 
         def next(self):
             item = self.rbiter.next()
-            item = item.cast(self.type).dereference()['_M_value_field']
+            item = item.cast(self.type).dereference()
+            item = get_value_from_Rb_tree_node(item)
             # FIXME: this is weird ... what to do?
             # Maybe a 'set' display hint?
             result = ('[%d]' % self.count, item)
diff --git a/libstdc++-v3/testsuite/libstdc++-prettyprinters/simple.cc b/libstdc++-v3/testsuite/libstdc++-prettyprinters/simple.cc
index 66ae8f7..030207a 100644
--- a/libstdc++-v3/testsuite/libstdc++-prettyprinters/simple.cc
+++ b/libstdc++-v3/testsuite/libstdc++-prettyprinters/simple.cc
@@ -1,4 +1,4 @@
-// If you modify this, please update debug.cc as well.
+// If you modify this, please update simple11.cc and debug.cc as well.
 
 // { dg-do run }
 // { dg-options "-g -O0" }
diff --git a/libstdc++-v3/testsuite/libstdc++-prettyprinters/simple11.cc b/libstdc++-v3/testsuite/libstdc++-prettyprinters/simple11.cc
new file mode 100644
index 0000000..e94bea6
--- /dev/null
+++ b/libstdc++-v3/testsuite/libstdc++-prettyprinters/simple11.cc
@@ -0,0 +1,92 @@
+// If you modify this, please update simple.cc and debug.cc as well.
+
+// { dg-do run }
+// { dg-options "-g -O0 -std=gnu++11" }
+
+// Copyright (C) 2011-2014 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <string>
+#include <deque>
+#include <bitset>
+#include <iostream>
+#include <list>
+#include <map>
+#include <set>
+#include <ext/slist>
+
+int
+main()
+{
+  std::string tem;
+  std::string str = "zardoz";
+// { dg-final { note-test str "\"zardoz\"" } }
+
+  std::bitset<10> bs;
+  bs[0] = 1;
+  bs[5] = 1;
+  bs[7] = 1;
+// { dg-final { note-test bs {std::bitset = {[0] = 1, [5] = 1, [7] = 1}} } }
+
+  std::deque<std::string> deq;
+  deq.push_back("one");
+  deq.push_back("two");
+// { dg-final { note-test deq {std::deque with 2 elements = {"one", "two"}} } }
+
+  std::deque<std::string>::iterator deqiter = deq.begin();
+// { dg-final { note-test deqiter {"one"} } }
+
+  std::list<std::string> lst;
+  lst.push_back("one");
+  lst.push_back("two");
+// { dg-final { note-test lst {std::list = {[0] = "one", [1] = "two"}} } }
+
+  std::list<std::string>::iterator lstiter = lst.begin();
+  tem = *lstiter;
+// { dg-final { note-test lstiter {"one"}} }
+
+  std::list<std::string>::const_iterator lstciter = lst.begin();
+  tem = *lstciter;
+// { dg-final { note-test lstciter {"one"}} }
+
+  std::map<std::string, int> mp;
+  mp["zardoz"] = 23;
+// { dg-final { note-test mp {std::map with 1 elements = {["zardoz"] = 23}} } }
+
+  std::map<std::string, int>::iterator mpiter = mp.begin();
+// { dg-final { note-test mpiter {{first = "zardoz", second = 23}} } }
+
+  std::set<std::string> sp;
+  sp.insert("clownfish");
+  sp.insert("barrel");
+// { dg-final { note-test sp {std::set with 2 elements = {[0] = "barrel", [1] = "clownfish"}} } }
+
+  std::set<std::string>::const_iterator spciter = sp.begin();
+// { dg-final { note-test spciter {"barrel"} } }
+
+  __gnu_cxx::slist<int> sll;
+  sll.push_front(23);
+  sll.push_front(47);
+// { dg-final { note-test sll {__gnu_cxx::slist = {[0] = 47, [1] = 23}} } }
+
+  __gnu_cxx::slist<int>::iterator slliter = sll.begin();
+// { dg-final { note-test slliter {47} } }
+
+  return 0;			// Mark SPOT
+}
+
+// { dg-final { gdb-test SPOT } }