GN: Use special toolchain for nacl64.exe, force is_component_build off

build/toolchain/win/BUILD.gn

 # 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/sanitizers/sanitizers.gni")
 import("//build/config/win/visual_studio_version.gni")
 import("//build/toolchain/goma.gni")
 import("//build/toolchain/toolchain.gni")
 
 # Should only be running on Windows.
@@ skipping 207 matching lines @@
       description = copy_description
     }
 
     # When invoking this toolchain not as the default one, these args will be
     # passed to the build. They are ignored when this is the default toolchain.
     toolchain_args() {
       current_cpu = invoker.toolchain_cpu
       if (defined(invoker.toolchain_os)) {
         current_os = invoker.toolchain_os
       }
-      if (defined(invoker.is_clang)) {
-        is_clang = invoker.is_clang
-      }
+
+      forward_variables_from(invoker,
+                             [
+                               "is_clang",
+                               "is_component_build",
+                             ])
 
       # This value needs to be passed through unchanged.
       host_toolchain = host_toolchain
     }
   }
 }
 
 if (host_os == "win") {
   clang_cl = "clang-cl.exe"
 } else {
@@ skipping 36 matching lines @@
 x64_toolchain_data = exec_script("setup_toolchain.py",
                                  [
                                    visual_studio_path,
                                    gyp_win_tool_path,
                                    windows_sdk_path,
                                    visual_studio_runtime_dirs,
                                    "x64",
                                  ],
                                  "scope")
 
-msvc_toolchain("x64") {
-  environment = "environment.x64"
-  toolchain_cpu = "x64"
-  cl = "${goma_prefix}\"${x64_toolchain_data.vc_bin_dir}/cl.exe\""
-  is_clang = false
+template("win_x64_toolchains") {
+  # TODO(mcgrathr): These assignments are only required because of
+  # crbug.com/395883.  Drop them if that ever gets fixed in GN.
+  concurrent_links = invoker.concurrent_links
+  goma_prefix = invoker.goma_prefix
+  x64_toolchain_data = invoker.x64_toolchain_data
+
+  msvc_toolchain(target_name) {
+    environment = "environment.x64"
+    toolchain_cpu = "x64"
+    cl = "${goma_prefix}\"${x64_toolchain_data.vc_bin_dir}/cl.exe\""
+    is_clang = false
+
+    forward_variables_from(invoker, [ "is_component_build" ])
+  }
+
+  msvc_toolchain("clang_" + target_name) {
+    environment = "environment.x64"
+    toolchain_cpu = "x64"
+    prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
+                         root_build_dir)
+    cl = "${goma_prefix}$prefix/${clang_cl}"
+    toolchain_os = "win"
+    is_clang = true
+
+    forward_variables_from(invoker, [ "is_component_build" ])
+  }
 }
 
-msvc_toolchain("clang_x64") {
-  environment = "environment.x64"
-  toolchain_cpu = "x64"
-  prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
-                       root_build_dir)
-  cl = "${goma_prefix}$prefix/${clang_cl}"
-  toolchain_os = "win"
-  is_clang = true
+win_x64_toolchains("x64") {
+  # TODO(mcgrathr): These assignments are only required because of
+  # crbug.com/395883.  Drop them if that ever gets fixed in GN.
+  concurrent_links = concurrent_links
+  goma_prefix = goma_prefix
+  x64_toolchain_data = x64_toolchain_data
+}
+
+# The nacl_win64 toolchain is nearly identical to the plain x64 toolchain.
+# It's used solely for building nacl64.exe (//components/nacl/broker:nacl64).
+# The only reason it's a separate toolchain is so that it can force
+# is_component_build to false in the toolchain_args() block, because
+# building nacl64.exe in component style does not work.
+win_x64_toolchains("nacl_win64") {
+  is_component_build = false
+
+  # TODO(mcgrathr): These assignments are only required because of
+  # crbug.com/395883.  Drop them if that ever gets fixed in GN.
+  concurrent_links = concurrent_links
+  goma_prefix = goma_prefix
+  x64_toolchain_data = x64_toolchain_data

[Dirk Pranke, 2016/01/26 01:42:41]

I'm not actually convinced that using the win_x64_toolchains() template makes
things shorter or easier to maintain, given that you have to add in so much
cruft to work around crbug.com/395883.

 }
 
 # WinRT toolchains. Only define these when targeting them.
 #
 # NOTE: This is currently broken because it references vc_bin_dir. brettw@
 # changed this around a bit, and I don't know what this should be set to
 # in terms of what setup_toolchain returns for a certain CPU architecture.
 if (target_os == "winrt_81" || target_os == "winrt_81_phone" ||
     target_os == "winrt_10") {
   msvc_toolchain("winrt_x86") {
     environment = "environment.winrt_x86"
     cl = "${goma_prefix}\"${vc_bin_dir}/cl.exe\""
     is_clang = false
 
     toolchain_cpu = "x86"
     toolchain_os = current_os
   }
 
   msvc_toolchain("winrt_x64") {
     environment = "environment.winrt_x64"
     cl = "${goma_prefix}\"${vc_bin_dir}/cl.exe\""
     is_clang = false
 
     toolchain_cpu = "x64"
     toolchain_os = current_os
   }
 }