[Support] Replace HashString with djbHash.

This removes the HashString function from StringExtraces and replaces
its uses with calls to djbHash from DJB.h

This is *almost* NFC. While the algorithm is identical, the djbHash
implementation in StringExtras used 0 as its seed while the
implementation in DJB uses 5381. The latter has been shown to result in
less collisions and improved avalanching.

https://reviews.llvm.org/D43615
(cherry picked from commit 77f7f965bc9499a9ae768a296ca5a1f7347d1d2c)

llvm-svn: 326081

1 files changed, 2 insertions, 2 deletions

diff --git a/lld/include/lld/Core/SymbolTable.h b/lld/include/lld/Core/SymbolTable.h
index 9c39a6ed507..cc2309a9068 100644
--- a/lld/include/lld/Core/SymbolTable.h
+++ b/lld/include/lld/Core/SymbolTable.h
@@ -12,7 +12,7 @@
 
 #include "lld/Common/LLVM.h"
 #include "llvm/ADT/DenseSet.h"
-#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/DJB.h"
 #include <cstring>
 #include <map>
 #include <vector>
@@ -65,7 +65,7 @@ private:
     static StringRef getEmptyKey() { return StringRef(); }
     static StringRef getTombstoneKey() { return StringRef(" ", 1); }
     static unsigned getHashValue(StringRef const val) {
-      return llvm::HashString(val);
+      return llvm::djbHash(val);
     }
     static bool isEqual(StringRef const lhs, StringRef const rhs) {
       return lhs.equals(rhs);