diff --git a/llvm/include/llvm/ToolDrivers/llvm-dlltool/DlltoolDriver.h b/llvm/include/llvm/ToolDrivers/llvm-dlltool/DlltoolDriver.h
index d144f62f1cc1a..30a260c52f1d9 100644
--- a/llvm/include/llvm/ToolDrivers/llvm-dlltool/DlltoolDriver.h
+++ b/llvm/include/llvm/ToolDrivers/llvm-dlltool/DlltoolDriver.h
@@ -14,10 +14,12 @@
 #ifndef LLVM_TOOLDRIVERS_LLVM_DLLTOOL_DLLTOOLDRIVER_H
 #define LLVM_TOOLDRIVERS_LLVM_DLLTOOL_DLLTOOLDRIVER_H
 
+#include "llvm/Support/Compiler.h"
+
 namespace llvm {
 template <typename T> class ArrayRef;
 
-int dlltoolDriverMain(ArrayRef<const char *> ArgsArr);
+LLVM_ABI int dlltoolDriverMain(ArrayRef<const char *> ArgsArr);
 } // namespace llvm
 
 #endif
diff --git a/llvm/include/llvm/ToolDrivers/llvm-lib/LibDriver.h b/llvm/include/llvm/ToolDrivers/llvm-lib/LibDriver.h
index 23a2fc348a892..43fc5d72d3a89 100644
--- a/llvm/include/llvm/ToolDrivers/llvm-lib/LibDriver.h
+++ b/llvm/include/llvm/ToolDrivers/llvm-lib/LibDriver.h
@@ -14,11 +14,12 @@
 #ifndef LLVM_TOOLDRIVERS_LLVM_LIB_LIBDRIVER_H
 #define LLVM_TOOLDRIVERS_LLVM_LIB_LIBDRIVER_H
 
+#include "llvm/Support/Compiler.h"
+
 namespace llvm {
 template <typename T> class ArrayRef;
 
-int libDriverMain(ArrayRef<const char *> ARgs);
-
+LLVM_ABI int libDriverMain(ArrayRef<const char *> ARgs);
 }
 
 #endif