Add unwrap function

gdb/data-directory/Makefile.in

@@ -76,6 +76,7 @@ PYTHON_FILE_LIST = \
 	gdb/command/explore.py \
 	gdb/function/__init__.py \
 	gdb/function/as_string.py \
+	gdb/function/unwrap.py \
 	gdb/function/caller_is.py \
 	gdb/function/strfns.py \
 	gdb/printer/__init__.py \

gdb/python/lib/gdb/function/unwrap.py

@@ -0,0 +1,63 @@
+# Copyright (C) 2016 Free Software Foundation, Inc.
+
+# This program 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 of the License, or
+# (at your option) any later version.
+#
+# This program 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 program.  If not, see <http://www.gnu.org/licenses/>.
+
+import gdb
+
+UNWRAP_MAP = {
+  'core::cell::Cell<' : 'value',
+  'core::cell::UnsafeCell<' : 'value',
+  'core::cell::RefCell<' : 'value',
+  'alloc::rc::Rc<' : 'ptr',
+  'alloc::rc::RcBox<' : 'value',
+  'core::ptr::Shared<' : 'pointer',
+  'alloc::arc::Arc<' : 'ptr',
+  'alloc::arc::ArcInner<' : 'data',
+  'std::sync::mutex::Mutex<' : 'data',
+  'core::nonzero::NonZero<' : '__0',
+}
+
+class Unwrap(gdb.Function):
+    """Return the string representation of a value.
+
+Usage:
+  $_as_string(value)
+
+Arguments:
+
+  value: A gdb.Value.
+
+Returns:
+  The string representation of the value.
+"""
+
+    def __init__(self):
+        super(Unwrap, self).__init__("unwrap")
+
+    def invoke(self, val):
+        import code
+        # code.interact(local=locals())
+        if val.type.code is gdb.TYPE_CODE_PTR:
+            return self.invoke(val.referenced_value())
+
+        for k,v in UNWRAP_MAP.iteritems():
+            if val.type.name.startswith(k):
+                try:
+                    inner = val[v]
+                    return self.invoke(inner)
+                except gdb.error:
+                    return val
+        return val
+
+Unwrap()