diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -13873,7 +13873,7 @@
   // Don't warn about 'main'.
   if (isa<TranslationUnitDecl>(FD->getDeclContext()->getRedeclContext()))
     if (IdentifierInfo *II = FD->getIdentifier())
-      if (II->isStr("main"))
+      if (II->isStr("main") || II->isStr("efi_main"))
         return false;
 
   // Don't warn about inline functions.
diff --git a/clang/test/Sema/no-warn-missing-prototype-efi.c b/clang/test/Sema/no-warn-missing-prototype-efi.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Sema/no-warn-missing-prototype-efi.c
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -fsyntax-only -Wmissing-prototypes -x c -ffreestanding -verify %s
+// RUN: %clang_cc1 -fsyntax-only -Wmissing-prototypes -x c++ -ffreestanding -verify %s
+// expected-no-diagnostics
+int efi_main() {
+  return 0;
+}