clang/win/gn: Actually build 32-bit .obj files in 32-bit builds.

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 264 matching lines @@
     toolchain_cpu = "x86"
     cl = "${goma_prefix}\"${x86_toolchain_data.vc_bin_dir}/cl.exe\""
     is_clang = false
   }
 
   msvc_toolchain("clang_x86") {
     environment = "environment.x86"
     toolchain_cpu = "x86"
     prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
                          root_build_dir)
-    cl = "${goma_prefix}$prefix/${clang_cl}"
+    cl = "${goma_prefix}$prefix/${clang_cl} -m32"

[Dirk Pranke, 2016/05/06 15:53:58]

Shouldn't this already be being set here:

https://code.google.com/p/chromium/codesearch?q=build%2Fconfig%2Fwin%2FBUILD....

?

[Nico, 2016/05/06 16:21:33]

Oh, great point! It seems to not always have an effect when it's set there. I
unchecked cq and will investigate, thanks.

[Nico, 2016/05/06 20:10:21]

mini_installer does

  configs -= [ "//build/config/compiler:compiler" ]

https://code.google.com/p/chromium/codesearch#chromium/src/chrome/installer/m...

which looks a bit...uh, surprising to me. I guess that means "I mean it" flags
like -m32 / -m64 need to be part of the toolchain instead of the compiler config
then? :-/

     toolchain_os = "win"
     is_clang = true
   }
 }
 
 # 64-bit toolchains.
 x64_toolchain_data = exec_script("setup_toolchain.py",
                                  [
                                    visual_studio_path,
                                    gyp_win_tool_path,
@@ skipping 18 matching lines @@
     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/${clang_cl}"
+    cl = "${goma_prefix}$prefix/${clang_cl} -m64"
     toolchain_os = "win"
     is_clang = true
 
     forward_variables_from(invoker, [ "is_component_build" ])
   }
 }
 
 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.
@@ skipping 36 matching lines @@
 
   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
   }
 }