diff --git a/Makefile.rules b/Makefile.rules
index 410a1422a88..21686aa2428 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -392,6 +392,17 @@ endif
   LD.Flags += -Wl,--no-relax
 endif
 
+# GNU ld/PECOFF accepts but ignores them below;
+#   --version-script
+#   --export-dynamic
+#   --rpath
+# FIXME: autoconf should be aware of them.
+ifneq (,$(filter $(HOST_OS),Cygwin MingW))
+  HAVE_LINK_VERSION_SCRIPT := 0
+  RPATH :=
+  RDYNAMIC := -Wl,--export-all-symbols
+endif
+
 #--------------------------------------------------------------------
 # Directory locations
 #--------------------------------------------------------------------
@@ -949,11 +960,6 @@ ifdef EXPORTED_SYMBOL_FILE
 # First, set up the native export file, which may differ from the source
 # export file.
 
-# The option --version-script is not effective on GNU ld win32.
-ifneq (,$(filter $(HOST_OS),Cygwin MingW))
-  HAVE_LINK_VERSION_SCRIPT := 0
-endif
-
 ifeq ($(HOST_OS),Darwin)
 # Darwin convention prefixes symbols with underscores.
 NativeExportsFile := $(ObjDir)/$(notdir $(EXPORTED_SYMBOL_FILE)).sed
diff --git a/unittests/CMakeLists.txt b/unittests/CMakeLists.txt
index 41e20cfc902..7953fac3bfa 100644
--- a/unittests/CMakeLists.txt
+++ b/unittests/CMakeLists.txt
@@ -82,6 +82,10 @@ endif()
 
 add_llvm_unittest(JIT ${JITTestsSources})
 
+if(MINGW)
+  set_property(TARGET JITTests PROPERTY LINK_FLAGS -Wl,--export-all-symbols)
+endif()
+
 add_llvm_unittest(Transforms
   Transforms/Utils/Cloning.cpp
   )
diff --git a/unittests/Makefile.unittest b/unittests/Makefile.unittest
index 9a75b2c2eb8..8be6174cb90 100644
--- a/unittests/Makefile.unittest
+++ b/unittests/Makefile.unittest
@@ -35,9 +35,11 @@ endif
 TESTLIBS = -lGoogleTest -lUnitTestMain
 
 ifeq ($(ENABLE_SHARED), 1)
-  # Add the absolute path to the dynamic library.  This is ok because
-  # we'll never install unittests.
-  LD.Flags += $(RPATH) -Wl,$(SharedLibDir)
+  ifneq (,$(RPATH))
+    # Add the absolute path to the dynamic library.  This is ok because
+    # we'll never install unittests.
+    LD.Flags += $(RPATH) -Wl,$(SharedLibDir)
+  endif
   # Also set {DYLD,LD}_LIBRARY_PATH because OSX ignores the rpath most
   # of the time.
   Run.Shared := $(SHLIBPATH_VAR)="$(SharedLibDir)$${$(SHLIBPATH_VAR):+:}$$$(SHLIBPATH_VAR)"