Add a new (simple) StringMap::clear method, patch by Pratik
Solanki!

llvm-svn: 53008
diff --git a/llvm/lib/CodeGen/CollectorMetadata.cpp b/llvm/lib/CodeGen/CollectorMetadata.cpp
index 7a5a699..5b8c7c7 100644
--- a/llvm/lib/CodeGen/CollectorMetadata.cpp
+++ b/llvm/lib/CodeGen/CollectorMetadata.cpp
@@ -112,10 +112,7 @@
 
 void CollectorModuleMetadata::clear() {
   Map.clear();
-  
-  // TODO: StringMap should provide a clear method.
-  while (!NameMap.empty())
-    NameMap.erase(NameMap.begin());
+  NameMap.clear();
   
   for (iterator I = begin(), E = end(); I != E; ++I)
     delete *I;