Win/Clang: Use order files for linking {chrome,chrome_child}.dll

Bug: 728324
Change-Id: Id007d43ea6468ce3ed8601c4e848861c224ef578
Reviewed-on: https://chromium-review.googlesource.com/529684
Commit-Queue: Hans Wennborg <hans@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#478747}

.gitignore

@@ -69,6 +69,10 @@ vs-chromium-project.txt
 /cdm
 /ceee/internal/
 /chrome/angle_unittests_run.xml
+/chrome/build/chrome.x64.orderfile
+/chrome/build/chrome.x86.orderfile
+/chrome/build/chrome_child.x64.orderfile
+/chrome/build/chrome_child.x86.orderfile
 /chrome/content_gl_tests_run.xml
 /chrome/gl_tests_run.xml
 /chrome/gles2_conform_test_run.xml

DEPS

@@ -738,6 +738,19 @@ hooks = [
                 '-s', 'src/buildtools/linux64/clang-format.sha1',
     ],
   },
+  # Pull order files for the win/clang build.
+  {
+    'name': 'orderfiles_win',
+    'pattern': '.',
+    'action': [ 'python',
+                'src/third_party/depot_tools/download_from_google_storage.py',
+                '--no_resume',
+                '--platform=win32',
+                '--no_auth',
+                '--bucket', 'chromium-browser-clang/orderfiles',
+                '-d', 'src/chrome/build',
+    ],
+  },
   # Pull luci-go binaries (isolate, swarming) using checked-in hashes.
   {
     'name': 'luci-go_win',

chrome/BUILD.gn

@@ -452,6 +452,22 @@ if (is_win) {
     if (enable_package_mash_services) {
       deps += embedded_mash_service_deps
     }
+
+    if (is_clang && is_official_build && !use_lld) {
+      orderfile = "build/chrome.$target_cpu.orderfile"
+      rebased_orderfile = rebase_path(orderfile, root_build_dir)
+      inputs = [
+        orderfile,
+      ]
+      ldflags += [
+        "/order:@$rebased_orderfile",
+
+        # Ignore warnings about missing functions or functions not in their
+        # own section.
+        "/ignore:4037",
+        "/ignore:4065",
+      ]
+    }
   }
 
   if (is_multi_dll_chrome) {
@@ -500,6 +516,22 @@ if (is_win) {
         "/DELAYLOAD:wininet.dll",
       ]
 
+      if (is_clang && is_official_build && !use_lld) {
+        orderfile = "build/chrome_child.$target_cpu.orderfile"
+        rebased_orderfile = rebase_path(orderfile, root_build_dir)
+        inputs = [
+          orderfile,
+        ]
+        ldflags += [
+          "/order:@$rebased_orderfile",
+
+          # Ignore warnings about missing functions or functions not in their
+          # own section.
+          "/ignore:4037",
+          "/ignore:4065",
+        ]
+      }
+
       if (symbol_level == 2) {
         # Incremental linking doesn't work on this target in debug mode with
         # full symbols, but does work in other cases, including minimal

chrome/build/OWNERS

+hans@chromium.org
+thakis@chromium.org

chrome/build/README

+How to create the order files
+=============================
+TODO(hans): Add proper instructions here.
+
+The current order files were created with this hack:
+https://codereview.chromium.org/2924093003

chrome/build/chrome.x64.orderfile.sha1

+9ae828ec3366bbc58046f009b5195552e1dc3030
\ No newline at end of file

chrome/build/chrome.x86.orderfile.sha1

+c30ec6aff8e403cc42964c6a18ffbdf7de85d4a8
\ No newline at end of file

chrome/build/chrome_child.x64.orderfile.sha1

+389514001c89d7e6049527396cd7624b15dc2456
\ No newline at end of file

chrome/build/chrome_child.x86.orderfile.sha1

+e9133bf86f174c1eb4096de82d39bd83c3d4a6d4
\ No newline at end of file