Index: llvm/trunk/utils/gn/secondary/lld/test/BUILD.gn
===================================================================
--- llvm/trunk/utils/gn/secondary/lld/test/BUILD.gn
+++ llvm/trunk/utils/gn/secondary/lld/test/BUILD.gn
@@ -80,6 +80,7 @@
     ":lit_site_cfg",
     ":lit_unit_site_cfg",
     "//lld/tools/lld:symlinks",
+    "//lld/unittests",
     "//llvm/tools/llc",
     "//llvm/tools/llvm-ar:symlinks",
     "//llvm/tools/llvm-as",
@@ -101,8 +102,6 @@
     "//llvm/utils/not",
   ]
   testonly = true
-
-  # FIXME: Add dep on "//lld/unittests" target once it exists.
 }
 
 # This is the action that runs all of lld's tests, check-lld.
Index: llvm/trunk/utils/gn/secondary/lld/unittests/BUILD.gn
===================================================================
--- llvm/trunk/utils/gn/secondary/lld/unittests/BUILD.gn
+++ llvm/trunk/utils/gn/secondary/lld/unittests/BUILD.gn
@@ -0,0 +1,7 @@
+group("unittests") {
+  deps = [
+    "DriverTests",
+    "MachOTests",
+  ]
+  testonly = true
+}
Index: llvm/trunk/utils/gn/secondary/lld/unittests/DriverTests/BUILD.gn
===================================================================
--- llvm/trunk/utils/gn/secondary/lld/unittests/DriverTests/BUILD.gn
+++ llvm/trunk/utils/gn/secondary/lld/unittests/DriverTests/BUILD.gn
@@ -0,0 +1,15 @@
+executable("DriverTests") {
+  # test/Unit/lit.cfg expects unittests in LLD_BINARY_DIR/unittest
+  output_dir = target_out_dir
+
+  configs += [ "//llvm/utils/gn/build:lld_code" ]
+  deps = [
+    "//lld/lib/Driver",
+    "//lld/lib/ReaderWriter/MachO",
+    "//llvm/utils/unittest/UnitTestMain",
+  ]
+  sources = [
+    "DarwinLdDriverTest.cpp",
+  ]
+  testonly = true
+}
Index: llvm/trunk/utils/gn/secondary/lld/unittests/MachOTests/BUILD.gn
===================================================================
--- llvm/trunk/utils/gn/secondary/lld/unittests/MachOTests/BUILD.gn
+++ llvm/trunk/utils/gn/secondary/lld/unittests/MachOTests/BUILD.gn
@@ -0,0 +1,19 @@
+executable("MachOTests") {
+  # test/Unit/lit.cfg expects unittests in LLD_BINARY_DIR/unittest
+  output_dir = target_out_dir
+
+  configs += [ "//llvm/utils/gn/build:lld_code" ]
+  deps = [
+    "//lld/lib/Driver",
+    "//lld/lib/ReaderWriter/MachO",
+    "//lld/lib/ReaderWriter/YAML",
+    "//llvm/utils/unittest/UnitTestMain",
+  ]
+  sources = [
+    "MachONormalizedFileBinaryReaderTests.cpp",
+    "MachONormalizedFileBinaryWriterTests.cpp",
+    "MachONormalizedFileToAtomsTests.cpp",
+    "MachONormalizedFileYAMLTests.cpp",
+  ]
+  testonly = true
+}
Index: llvm/trunk/utils/gn/secondary/llvm/utils/unittest/BUILD.gn
===================================================================
--- llvm/trunk/utils/gn/secondary/llvm/utils/unittest/BUILD.gn
+++ llvm/trunk/utils/gn/secondary/llvm/utils/unittest/BUILD.gn
@@ -0,0 +1,40 @@
+import("//llvm/utils/gn/build/libs/pthread/enable.gni")
+
+# Used to push the gtest include directories to things depending on :googletest.
+config("googletest_config") {
+  include_dirs = [
+    "googlemock/include",
+    "googletest/include",
+  ]
+
+  # LLVM requires C++11 but gtest doesn't correctly detect the availability
+  # of C++11 on MSVC, so we force it on.
+  defines = [
+    "GTEST_LANG_CXX11",
+    "GTEST_HAS_TR1_TUPLE=0",
+  ]
+  if (host_os == "win") {
+    defines += [ "GTEST_OS_WINDOWS" ]
+  }
+  if (!llvm_enable_threads) {
+    defines += [ "GTEST_HAS_PTHREAD=0" ]
+  }
+  defines += [ "GTEST_HAS_RTTI=0" ]
+}
+
+static_library("gtest") {
+  deps = [
+    "//llvm/lib/Support",
+  ]
+  include_dirs = [
+    "googletest",  # For including src/gtest.cc
+    "googlemock",  # For including src/gmock.cc
+  ]
+  public_configs = [ ":googletest_config" ]
+  configs -= [ "//llvm/utils/gn/build:warn_covered_switch_default" ]
+  sources = [
+    "googlemock/src/gmock-all.cc",
+    "googletest/src/gtest-all.cc",
+  ]
+  testonly = true
+}
Index: llvm/trunk/utils/gn/secondary/llvm/utils/unittest/UnitTestMain/BUILD.gn
===================================================================
--- llvm/trunk/utils/gn/secondary/llvm/utils/unittest/UnitTestMain/BUILD.gn
+++ llvm/trunk/utils/gn/secondary/llvm/utils/unittest/UnitTestMain/BUILD.gn
@@ -0,0 +1,25 @@
+source_set("UnitTestMain") {
+  deps = [
+    "//llvm/lib/Support",
+  ]
+
+  # Make targets depending on this also depend on gtest, to get the gtest
+  # include_dir.
+  public_deps = [
+    "..:gtest",
+  ]
+  sources = [
+    "TestMain.cpp",
+  ]
+  testonly = true
+}
+
+# Nothing depends on this target, but llvm-config expects it to exist when
+# it runs with `--link-static --system-libs`, so humor it.
+static_library("gtest_main") {
+  deps = [
+    ":UnitTestMain",
+  ]
+  complete_static_lib = true
+  testonly = true
+}