Index: lld/COFF/Config.h
===================================================================
--- lld/COFF/Config.h
+++ lld/COFF/Config.h
@@ -10,6 +10,7 @@
 #ifndef LLD_COFF_CONFIG_H
 #define LLD_COFF_CONFIG_H
 
+#include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Object/COFF.h"
 #include "llvm/Support/CachePruning.h"
@@ -103,6 +104,11 @@
   // True if we are creating a DLL.
   bool DLL = false;
   StringRef Implib;
+
+  // Export args in directive sections and command line,
+  // parsed after deduplication.
+  llvm::SetVector<StringRef> RawExports;
+
   std::vector<Export> Exports;
   std::set<std::string> DelayLoads;
   std::map<std::string, int> DLLOrder;
Index: lld/COFF/Driver.cpp
===================================================================
--- lld/COFF/Driver.cpp
+++ lld/COFF/Driver.cpp
@@ -245,15 +245,7 @@
       Config->Entry = addUndefined(mangle(Arg->getValue()));
       break;
     case OPT_export: {
-      Export E = parseExport(Arg->getValue());
-      if (Config->Machine == I386 && Config->MinGW) {
-        if (!isDecorated(E.Name))
-          E.Name = Saver.save("_" + E.Name);
-        if (!E.ExtName.empty() && !isDecorated(E.ExtName))
-          E.ExtName = Saver.save("_" + E.ExtName);
-      }
-      E.Directives = true;
-      Config->Exports.push_back(E);
+      Config->RawExports.insert(Arg->getValue());
       break;
     }
     case OPT_failifmismatch:
@@ -1105,10 +1097,20 @@
     }
   }
 
+  const size_t NumDirectiveExports = Config->RawExports.size();
+
   // Handle /export
   for (auto *Arg : Args.filtered(OPT_export)) {
-    Export E = parseExport(Arg->getValue());
-    if (Config->Machine == I386) {
+    Config->RawExports.insert(Arg->getValue());
+  }
+
+  // Parse deduplicated Exports in directive sections and command line.
+  for (size_t I = 0, RE = Config->RawExports.size(); I != RE; ++I) {
+    Export E = parseExport(Config->RawExports[I]);
+    if (I < NumDirectiveExports)
+      E.Directives = true;
+
+    if (Config->Machine == I386 && (!E.Directives || Config->MinGW)) {
       if (!isDecorated(E.Name))
         E.Name = Saver.save("_" + E.Name);
       if (!E.ExtName.empty() && !isDecorated(E.ExtName))