1 files changed, 5 insertions, 0 deletions
diff --git a/lld/lib/ReaderWriter/PECOFF/PECOFFLinkingContext.cpp b/lld/lib/ReaderWriter/PECOFF/PECOFFLinkingContext.cpp
index 4dbb5d70a46..b0e5546592b 100644
--- a/lld/lib/ReaderWriter/PECOFF/PECOFFLinkingContext.cpp
+++ b/lld/lib/ReaderWriter/PECOFF/PECOFFLinkingContext.cpp
@@ -59,6 +59,11 @@ bool PECOFFLinkingContext::validateImpl(raw_ostream &diagnostics) {
     return true;
   }
 
+  if (_subsystem == llvm::COFF::IMAGE_SUBSYSTEM_UNKNOWN) {
+    diagnostics << "Error: Subsystem is not specified\n";
+    return true;
+  }
+
   _reader = createReaderPECOFF(*this);
   _writer = createWriterPECOFF(*this);
   return false;