diff --git a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
--- a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
@@ -327,13 +327,6 @@
     "LLVM_DEFAULT_TARGET_TRIPLE=$llvm_target_triple",
     "LLVM_HAS_ATOMICS=1",
     "LLVM_HOST_TRIPLE=$llvm_current_triple",
-    "LLVM_NATIVE_ARCH=$native_target",
-    "LLVM_NATIVE_ASMPARSER=1",
-    "LLVM_NATIVE_ASMPRINTER=1",
-    "LLVM_NATIVE_DISASSEMBLER=1",
-    "LLVM_NATIVE_TARGET=1",
-    "LLVM_NATIVE_TARGETINFO=1",
-    "LLVM_NATIVE_TARGETMC=1",
     "LLVM_USE_INTEL_JITEVENTS=",
     "LLVM_USE_OPROFILE=",
     "LLVM_USE_PERF=",
@@ -342,8 +335,29 @@
     "LLVM_VERSION_PATCH=$llvm_version_patch",
     "PACKAGE_VERSION=${llvm_version}svn",
     "LLVM_FORCE_ENABLE_STATS=",
+    "LLVM_NATIVE_ARCH=$native_target",
   ]
 
+  if (llvm_build_native_target) {
+    values += [
+      "LLVM_NATIVE_ASMPARSER=1",
+      "LLVM_NATIVE_ASMPRINTER=1",
+      "LLVM_NATIVE_DISASSEMBLER=1",
+      "LLVM_NATIVE_TARGET=1",
+      "LLVM_NATIVE_TARGETINFO=1",
+      "LLVM_NATIVE_TARGETMC=1",
+    ]
+  } else {
+    values += [
+      "LLVM_NATIVE_ASMPARSER=",
+      "LLVM_NATIVE_ASMPRINTER=",
+      "LLVM_NATIVE_DISASSEMBLER=",
+      "LLVM_NATIVE_TARGET=",
+      "LLVM_NATIVE_TARGETINFO=",
+      "LLVM_NATIVE_TARGETMC=",
+    ]
+  }
+
   if (current_os == "win") {
     values += [ "LLVM_ON_UNIX=" ]
   } else {
diff --git a/llvm/utils/gn/secondary/llvm/lib/MC/BUILD.gn b/llvm/utils/gn/secondary/llvm/lib/MC/BUILD.gn
--- a/llvm/utils/gn/secondary/llvm/lib/MC/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/lib/MC/BUILD.gn
@@ -2,6 +2,7 @@
   output_name = "LLVMMC"
   deps = [
     "//llvm/include/llvm/Config:config",
+    "//llvm/lib/BinaryFormat",
     "//llvm/lib/DebugInfo/CodeView",
     "//llvm/lib/Support",
   ]
diff --git a/llvm/utils/gn/secondary/llvm/lib/Target/targets.gni b/llvm/utils/gn/secondary/llvm/lib/Target/targets.gni
--- a/llvm/utils/gn/secondary/llvm/lib/Target/targets.gni
+++ b/llvm/utils/gn/secondary/llvm/lib/Target/targets.gni
@@ -35,6 +35,19 @@
   ]
 }
 
+# FIXME: This should be based off target_cpu once cross compiles work.
+if (host_cpu == "arm64") {
+  native_target = "AArch64"
+} else if (host_cpu == "arm") {
+  native_target = "ARM"
+} else if (host_cpu == "ppc" || host_cpu == "ppc64") {
+  native_target = "PowerPC"
+} else if (host_cpu == "x86" || host_cpu == "x64") {
+  native_target = "X86"
+} else {
+  assert(false, "Unsuppored host_cpu '$host_cpu'.")
+}
+
 # Validate that llvm_targets_to_build is set to a list of valid targets,
 # and remember which targets are built.
 llvm_build_AArch64 = false
@@ -43,6 +56,7 @@
 llvm_build_PowerPC = false
 llvm_build_WebAssembly = false
 llvm_build_X86 = false
+llvm_build_native_target = false
 foreach(target, llvm_targets_to_build) {
   if (target == "AArch64") {
     llvm_build_AArch64 = true
@@ -74,17 +88,8 @@
     # FIXME: Port the remaining targets.
     assert(false, "Unknown target '$target'.")
   }
-}
 
-# FIXME: This should be based off target_cpu once cross compiles work.
-if (host_cpu == "arm64") {
-  native_target = "AArch64"
-} else if (host_cpu == "arm") {
-  native_target = "ARM"
-} else if (host_cpu == "ppc" || host_cpu == "ppc64") {
-  native_target = "PowerPC"
-} else if (host_cpu == "x86" || host_cpu == "x64") {
-  native_target = "X86"
-} else {
-  assert(false, "Unsuppored host_cpu '$host_cpu'.")
+  if (target == native_target) {
+    llvm_build_native_target = true
+  }
 }
diff --git a/llvm/utils/llvm-build/llvmbuild/main.py b/llvm/utils/llvm-build/llvmbuild/main.py
--- a/llvm/utils/llvm-build/llvmbuild/main.py
+++ b/llvm/utils/llvm-build/llvmbuild/main.py
@@ -188,6 +188,32 @@
                 visit(c, depth + 1)
         visit(self.component_info_map['$ROOT'])
 
+    def gn_check(self):
+        from subprocess import check_output, CalledProcessError
+        from difflib import unified_diff
+
+        def togn(c):
+            return "//llvm" + c.subpath + ":" + c.subpath.rsplit("/", 1)[1]
+        indent = lambda l: " " * 4 + l
+
+        bypath = {v.subpath: v for v in self.component_info_map.values()}
+
+        for name in sorted(bypath):
+            comp = bypath[name]
+            if not hasattr(comp, "required_libraries"):
+                continue
+
+            print(togn(comp))
+
+            try:
+                cmd = "/usr/local/bin/gn desc /tmp/b {} deps".format(togn(comp)).split()
+                gndeps = sorted(check_output(cmd).strip().splitlines())
+            except CalledProcessError, e:
+                print(indent(" had trouble..." + str(e)))
+            else:
+                lldeps = sorted(togn(self.component_info_map[req_]) for req_ in comp.required_libraries)
+                print("\n".join(indent(l) for l in unified_diff(lldeps, gndeps)))
+
     def write_components(self, output_path):
         # Organize all the components by the directory their LLVMBuild file
         # should go in.
@@ -808,7 +834,7 @@
                                            'Function.cpp')):
             parser.error('invalid LLVM source root: %r' % source_root)
     else:
-        llvmbuild_path = os.path.dirname(__file__)
+        llvmbuild_path = os.path.dirname(os.path.abspath(__file__))
         llvm_build_path = os.path.dirname(llvmbuild_path)
         utils_path = os.path.dirname(llvm_build_path)
         source_root = os.path.dirname(utils_path)
@@ -829,7 +855,7 @@
 
     # Print the component tree, if requested.
     if opts.print_tree:
-        project_info.print_tree()
+        project_info.gn_check()
 
     # Write out the components, if requested. This is useful for auto-upgrading
     # the schema.