[COFF] Change a llvm::StringSet<> to llvm::DenseSet<StringRef>. NFC

The former stores strings and is therefore more expensive.

diff --git a/lld/COFF/Driver.h b/lld/COFF/Driver.h
index 64334ad..902f122 100644 (file)
--- a/lld/COFF/Driver.h
+++ b/lld/COFF/Driver.h
@@ -158,7 +158,7 @@ private:
   std::vector<StringRef> filePaths;
   std::vector<MemoryBufferRef> resources;
 
-  llvm::StringSet<> directivesExports;
+  llvm::DenseSet<StringRef> directivesExports;
 
   COFFLinkerContext &ctx;