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 04c5815e35f2b460950dde69ff3c1fae9e7452d6..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_;
@@ -59,6 +57,10 @@ namespace llvm {
       storage_.reserve(s);
     }
 
+    void resize(typename StorageT::size_type s) {
+      storage_.resize(s, nullVal_);
+    }
+
     void clear() {
       storage_.clear();
     }
@@ -66,7 +68,7 @@ namespace llvm {
     void grow(IndexT n) {
       unsigned NewSize = toIndex_(n) + 1;
       if (NewSize > storage_.size())
-        storage_.resize(NewSize, nullVal_);
+        resize(NewSize);
     }
 
     bool inBounds(IndexT n) const {