Fix missing C++ mode comment

[oota-llvm.git] / include / llvm / ADT / IndexedMap.h

diff --git a/include/llvm/ADT/IndexedMap.h b/include/llvm/ADT/IndexedMap.h
index 87126ea49187bc577f2b4793270b74c1a3f65693..5ba85c02792095ff75ef49e21ee1d172481234eb 100644 (file)
--- a/include/llvm/ADT/IndexedMap.h
+++ b/include/llvm/ADT/IndexedMap.h
@@ -20,22 +20,20 @@
 #ifndef LLVM_ADT_INDEXEDMAP_H
 #define LLVM_ADT_INDEXEDMAP_H
 
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallVector.h"
 #include <cassert>
 #include <functional>
-#include <vector>
 
 namespace llvm {
 
-  struct IdentityFunctor : public std::unary_function<unsigned, unsigned> {
-    unsigned operator()(unsigned Index) const {
-      return Index;
-    }
-  };
-
-  template <typename T, typename ToIndexT = IdentityFunctor>
+template <typename T, typename ToIndexT = llvm::identity<unsigned> >
   class IndexedMap {
     typedef typename ToIndexT::argument_type IndexT;
-    typedef std::vector<T> StorageT;
+    // Prefer SmallVector with zero inline storage over std::vector. IndexedMaps
+    // can grow very large and SmallVector grows more efficiently as long as T
+    // is trivially copyable.
+    typedef SmallVector<T, 0> StorageT;
     StorageT storage_;
     T nullVal_;
     ToIndexT toIndex_;