port cfi to gn

build/toolchain/gcc_toolchain.gni

Index: build/toolchain/gcc_toolchain.gni
diff --git a/build/toolchain/gcc_toolchain.gni b/build/toolchain/gcc_toolchain.gni
index bb3846c3bb6bd817cd9b00ab770142c909203ca6..a9f73f7be6da22da9f69bdcda7ba22455f28ddab 100644
--- a/build/toolchain/gcc_toolchain.gni
+++ b/build/toolchain/gcc_toolchain.gni
@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/sanitizers/sanitizers.gni")
 import("//build/toolchain/toolchain.gni")
 
 # This value will be inherited in the toolchain below.
@@ -173,7 +174,14 @@ template("gcc_toolchain") {
 
     tool("alink") {
       rspfile = "{{output}}.rsp"
-      command = "rm -f {{output}} && $ar rcs {{output}} @$rspfile"
+      arflags = ""
+      if (is_cfi && invoker.toolchain_os != "nacl") {
+        gold_plugin_path = rebase_path(
+                "//third_party/llvm-build/Release+Asserts/lib/LLVMgold.so",
+                root_build_dir)
+        arflags = "--plugin $gold_plugin_path"
+      }
+      command = "rm -f {{output}} && $ar rcs $arflags {{output}} @$rspfile"
       description = "AR {{output}}"
       rspfile_content = "{{inputs}}"
       outputs = [