diff --git a/llvm/lib/IR/DataLayout.cpp b/llvm/lib/IR/DataLayout.cpp
--- a/llvm/lib/IR/DataLayout.cpp
+++ b/llvm/lib/IR/DataLayout.cpp
@@ -171,7 +171,7 @@
     return "-m:l";
   if (T.isOSBinFormatMachO())
     return "-m:o";
-  if (T.isOSWindows() && T.isOSBinFormatCOFF())
+  if ((T.isOSWindows() || T.isUEFI()) && T.isOSBinFormatCOFF())
     return T.getArch() == Triple::x86 ? "-m:x" : "-m:w";
   if (T.isOSBinFormatXCOFF())
     return "-m:a";
diff --git a/llvm/lib/TargetParser/Triple.cpp b/llvm/lib/TargetParser/Triple.cpp
--- a/llvm/lib/TargetParser/Triple.cpp
+++ b/llvm/lib/TargetParser/Triple.cpp
@@ -799,6 +799,8 @@
   case Triple::x86_64:
     if (T.isOSWindows())
       return Triple::COFF;
+    else if (T.isUEFI())
+      return Triple::COFF;
     return Triple::ELF;
 
   case Triple::aarch64_be:
diff --git a/llvm/unittests/TargetParser/TripleTest.cpp b/llvm/unittests/TargetParser/TripleTest.cpp
--- a/llvm/unittests/TargetParser/TripleTest.cpp
+++ b/llvm/unittests/TargetParser/TripleTest.cpp
@@ -462,6 +462,7 @@
   EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
   EXPECT_EQ(Triple::UEFI, T.getOS());
   EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
+  EXPECT_EQ(Triple::COFF, T.getObjectFormat());
 
   T = Triple("wasm32-unknown-unknown");
   EXPECT_EQ(Triple::wasm32, T.getArch());