Index: MinGW/Driver.cpp
===================================================================
--- MinGW/Driver.cpp
+++ MinGW/Driver.cpp
@@ -136,6 +136,8 @@
     Add("-implib:" + StringRef(A->getValue()));
   if (auto *A = Args.getLastArg(OPT_stack))
     Add("-stack:" + StringRef(A->getValue()));
+  if (auto *A = Args.getLastArg(OPT_output_def))
+    Add("-output-def:" + StringRef(A->getValue()));
 
   if (auto *A = Args.getLastArg(OPT_o))
     Add("-out:" + StringRef(A->getValue()));
@@ -148,6 +150,8 @@
     Add("-dll");
   if (Args.hasArg(OPT_verbose))
     Add("-verbose");
+  if (Args.hasArg(OPT_export_all_symbols))
+    Add("-export-all-symbols");
 
   if (auto *A = Args.getLastArg(OPT_m)) {
     StringRef S = A->getValue();
Index: MinGW/Options.td
===================================================================
--- MinGW/Options.td
+++ MinGW/Options.td
@@ -8,6 +8,8 @@
   HelpText<"Add a directory to the library search path">;
 def entry: S<"entry">, MetaVarName<"<entry>">,
   HelpText<"Name of entry point symbol">;
+def export_all_symbols: F<"export-all-symbols">,
+    HelpText<"Export all symbols even if a def file or dllexport attributes are used">;
 def l: JoinedOrSeparate<["-"], "l">, MetaVarName<"<libName>">,
   HelpText<"Root name of library to use">;
 def m: JoinedOrSeparate<["-"], "m">, HelpText<"Set target emulation">;
@@ -17,6 +19,7 @@
 def o: JoinedOrSeparate<["-"], "o">, MetaVarName<"<path>">,
   HelpText<"Path to file to write output">;
 def out_implib: Separate<["--"], "out-implib">, HelpText<"Import library name">;
+def output_def: S<"output-def">, HelpText<"Output def file">;
 def shared: F<"shared">, HelpText<"Build a shared object">;
 def subs: S<"subsystem">, HelpText<"Specify subsystem">;
 def stack: S<"stack">;
Index: test/MinGW/driver.test
===================================================================
--- test/MinGW/driver.test
+++ test/MinGW/driver.test
@@ -72,3 +72,9 @@
 
 RUN: ld.lld -### -m i386pep foo.o | FileCheck -check-prefix MINGW-FLAG %s
 MINGW-FLAG: -lldmingw
+
+RUN: ld.lld -### -m i386pep foo.o --export-all-symbols | FileCheck -check-prefix EXPORT-ALL %s
+EXPORT-ALL: -export-all-symbols
+
+RUN: ld.lld -### -m i386pep foo.o --output-def out.def | FileCheck -check-prefix OUTPUT-DEF %s
+OUTPUT-DEF: -output-def:out.def