diff --git a/lldb/examples/synthetic/gnu_libstdcpp.py b/lldb/examples/synthetic/gnu_libstdcpp.py
--- a/lldb/examples/synthetic/gnu_libstdcpp.py
+++ b/lldb/examples/synthetic/gnu_libstdcpp.py
@@ -7,6 +7,94 @@
 # as it ships with Mac OS X 10.6.8 thru 10.8.0
 # You are encouraged to look at the STL implementation for your platform
 # before relying on these formatters to do the right thing for your setup
+class StdUnorderedMapSynthProvider:
+    def __init__(self, valobj, dict):
+        self.valobj = valobj
+        self.count = None
+
+    def extract_type(self):
+        logger = lldb.formatters.Logger.Logger()
+        list_type = self.valobj.GetType().GetUnqualifiedType()
+        if list_type.IsReferenceType():
+            list_type = list_type.GetDereferencedType()
+        if list_type.GetNumberOfTemplateArguments() > 0:
+            data_type = list_type.GetTemplateArgumentType(0)
+        else:
+            data_type = None
+        return data_type
+
+    def update(self): 
+        logger = lldb.formatters.Logger.Logger()
+        # preemptively setting this to None - we might end up changing our mind
+        # later
+        self.count = None
+        try:
+            self.head = self.valobj.GetChildMemberWithName('_M_h')
+            self.before_begin = self.head.GetChildMemberWithName('_M_before_begin')
+            self.next = self.before_begin.GetChildMemberWithName('_M_nxt')
+            self.data_type = self.extract_type()
+            self.skip_size = self.head.GetType().GetByteSize()
+            logger >> "Data type is this: " + str(self.data_type)
+            self.data_size = self.data_type.GetByteSize()
+        except:
+            pass
+        return False
+
+    def get_child_index(self, name):
+        logger = lldb.formatters.Logger.Logger()
+        try:
+            return int(name.lstrip('[').rstrip(']'))
+        except:
+            return -1
+
+    def get_child_key(self, index):
+        try:
+            logger = lldb.formatters.Logger.Logger()
+            offset = self.count - index - 1
+            current = self.next     
+            while offset > 0:
+                current = current.GetChildMemberWithName('_M_nxt')
+                offset = offset - 1
+            return current.CreateChildAtOffset('[' + str(index) + ']', self.next.GetType().GetByteSize(), self.data_type)
+        except:
+            logger >> "Error in get_child_key"
+            return None
+
+    def get_child_at_index(self, index):
+        logger = lldb.formatters.Logger.Logger()
+        logger >> "Being asked to fetch child[" + str(index) + "]"
+        if index < 0:
+            return None
+        if index >= self.num_children():
+            return None
+        try:
+            offset = self.count - index - 1
+            current = self.next     
+            while offset > 0:
+                current = current.GetChildMemberWithName('_M_nxt')
+                offset = offset - 1
+            key = self.get_child_key(index)
+            return current.CreateChildAtOffset('[' + str(key.GetValue()) + ']', self.next.GetType().GetByteSize() + 9, self.data_type)
+        
+        except:
+            logger >> "Error in get_child_at_index"
+            return None
+
+    def num_children(self):
+        logger = lldb.formatters.Logger.Logger()
+        if self.count is None:
+            self.count = self.num_children_impl()
+        return self.count
+
+    def num_children_impl(self):
+        logger = lldb.formatters.Logger.Logger()
+        try:
+            count = self.head.GetChildMemberWithName('_M_element_count').GetValueAsUnsigned(0)
+            logger >> "I have " + str(count) + " children available"
+            return count
+        except:
+            logger >> "Could not determine the size"
+            return 0
 
 
 class StdListSynthProvider:
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -918,6 +918,11 @@
       SyntheticChildrenSP(new ScriptedSyntheticChildren(
           stl_deref_flags,
           "lldb.formatters.cpp.gnu_libstdcpp.StdMapLikeSynthProvider")));
+  cpp_category_sp->GetRegexTypeSyntheticsContainer()->Add(
+      RegularExpression("^std::unordered_(multi)?(map|set)<.+> >$"),
+      SyntheticChildrenSP(new ScriptedSyntheticChildren(
+          stl_deref_flags,
+          "lldb.formatters.cpp.gnu_libstdcpp.StdUnorderedMapSynthProvider")));
   cpp_category_sp->GetRegexTypeSyntheticsContainer()->Add(
       RegularExpression("^std::(__cxx11::)?list<.+>(( )?&)?$"),
       SyntheticChildrenSP(new ScriptedSyntheticChildren(
@@ -949,6 +954,10 @@
       RegularExpression("^std::multiset<.+> >(( )?&)?$"),
       TypeSummaryImplSP(
           new StringSummaryFormat(stl_summary_flags, "size=${svar%#}")));
+  cpp_category_sp->GetRegexTypeSummariesContainer()->Add(
+      RegularExpression("^std::unordered_(multi)?(map|set)<.+> >$"),
+      TypeSummaryImplSP(
+          new StringSummaryFormat(stl_summary_flags, "size=${svar%#}")));
   cpp_category_sp->GetRegexTypeSummariesContainer()->Add(
       RegularExpression("^std::(__cxx11::)?list<.+>(( )?&)?$"),
       TypeSummaryImplSP(