Implement arflags in the GN build.

build/toolchain/gcc_toolchain.gni

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/nacl/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/goma.gni")
 import("//build/toolchain/toolchain.gni")
 
-# This value will be inherited in the toolchain below.
+# "concurrent_links" is a toolchain variable. By computing it here rather than
+# inside the toolchain, the exec_script will only get run once rather than
+# each time the toolchain template is invoked.
 if (allow_posix_link_time_opt || is_cfi) {
-  concurrent_links =
+  concurrent_links_ =
       exec_script("get_concurrent_links.py", [ "--lto" ], "value")
 } else {
-  concurrent_links = exec_script("get_concurrent_links.py", [], "value")
+  concurrent_links_ = exec_script("get_concurrent_links.py", [], "value")
 }
 
 # This template defines a toolchain for something that works like gcc
 # (including clang).
 #
 # It requires the following variables specifying the executables to run:
 #  - cc
 #  - cxx
 #  - ar
 #  - ld
@@ skipping 67 matching lines @@
   toolchain(target_name) {
     assert(defined(invoker.cc), "gcc_toolchain() must specify a \"cc\" value")
     assert(defined(invoker.cxx), "gcc_toolchain() must specify a \"cxx\" value")
     assert(defined(invoker.ar), "gcc_toolchain() must specify a \"ar\" value")
     assert(defined(invoker.ld), "gcc_toolchain() must specify a \"ld\" value")
     assert(defined(invoker.toolchain_cpu),
            "gcc_toolchain() must specify a \"toolchain_cpu\"")
     assert(defined(invoker.toolchain_os),
            "gcc_toolchain() must specify a \"toolchain_os\"")
 
+    concurrent_links = concurrent_links_
+
     if (defined(invoker.cc_wrapper)) {
       cc_wrapper = invoker.cc_wrapper
     }
     if (defined(invoker.use_goma)) {
       use_goma = invoker.use_goma
     }
     if (use_goma) {
       assert(cc_wrapper == "", "Goma and cc_wrapper can't be used together.")
       compiler_prefix = "$goma_dir/gomacc "
     } else if (cc_wrapper != "") {
@@ skipping 95 matching lines @@
       command = "$cc -MMD -MF $depfile ${rebuild_string}{{defines}} {{include_dirs}} {{asmflags}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
       description = "ASM {{output}}"
       outputs = [
         "$object_subdir/{{source_name_part}}.o",
       ]
     }
 
     tool("alink") {
       rspfile = "{{output}}.rsp"
-      arflags = ""
-      if ((allow_posix_link_time_opt || 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\""
-      }
 
       # This needs a Python script to avoid using simple sh features in this
       # command, in case the host does not use a POSIX shell (e.g. compiling
       # POSIX-like toolchains such as NaCl on Windows).
       ar_wrapper =
           rebase_path("//build/toolchain/gcc_ar_wrapper.py", root_build_dir)
-      command = "$python_path \"$ar_wrapper\" --output={{output}} --ar=\"$ar\" $arflags rcsD @\"$rspfile\""
+      command = "$python_path \"$ar_wrapper\" --output={{output}} --ar=\"$ar\" {{arflags}} rcsD @\"$rspfile\""
       description = "AR {{output}}"
       rspfile_content = "{{inputs}}"
       outputs = [
         "{{output_dir}}/{{target_output_name}}{{output_extension}}",
       ]
 
       # Shared libraries go in the target out directory by default so we can
       # generate different targets with the same name and not have them collide.
       default_output_dir = "{{target_out_dir}}"
       default_output_extension = ".a"
@@ skipping 228 matching lines @@
 
     forward_variables_from(invoker,
                            [
                              "toolchain_cpu",
                              "toolchain_os",
                              "use_gold",
                              "strip",
                            ])
   }
 }