diff --git a/libc/utils/HdrGen/CMakeLists.txt b/libc/utils/HdrGen/CMakeLists.txt
--- a/libc/utils/HdrGen/CMakeLists.txt
+++ b/libc/utils/HdrGen/CMakeLists.txt
@@ -1,5 +1,6 @@
 add_tablegen(libc-hdrgen llvm-libc
   Command.h
+  Command.cpp
   Generator.cpp
   Generator.h
   IncludeFileCommand.cpp
diff --git a/libc/utils/HdrGen/Command.h b/libc/utils/HdrGen/Command.h
--- a/libc/utils/HdrGen/Command.h
+++ b/libc/utils/HdrGen/Command.h
@@ -42,6 +42,8 @@
     }
   };
 
+  virtual ~Command();
+
   virtual void run(llvm::raw_ostream &OS, const ArgVector &Args,
                    llvm::StringRef StdHeader, llvm::RecordKeeper &Records,
                    const ErrorReporter &Reporter) const = 0;
diff --git a/libc/utils/HdrGen/Command.cpp b/libc/utils/HdrGen/Command.cpp
new file mode 100644
--- /dev/null
+++ b/libc/utils/HdrGen/Command.cpp
@@ -0,0 +1,7 @@
+#include "Command.h"
+
+namespace llvm_libc {
+
+Command::~Command() {}
+
+} // namespace llvm_libc