GN

What we've got here is a little GN MVP.  It's lacking any knobs and doesn't yet build anything but libskia, zlib, libpng, and libjpeg-turbo.  I've been hopping back and forth between Linux at work and Mac at home.  These seem to be at least partially working, enough to build and run cmake/example.cpp.

The xcode backend seems to work.  From here, we can start exploring how to handle other backends (cmake,Android make, Google3).  There are a couple things I want to try:
  - add another backend like vs or xcode to GN directly
  - intercept via a custom toolchain
  - reverse from ninja -t commands
That last option seems kind of fun.

This tries to piggyback on Chrome's GN setup as much as possible.  Chrome's got quite a lot figured out, and we're basically required to do this if we want to have a single GN build system shareable by Chrome, our bots, and other clients.

This pulls in some new DEPS:
   - build: Chrome's GN configuration, and much more
   - buildtools: hashes for gn binary, pulled via hooks
   - tools/clang: hashes for Chrome's clang, pulled via hooks into third_party/llvm-build
It additionally symlinks tools/gyp to third_party/externals/gyp.  GN pulls some stuff from tools/gyp on Mac.

Have not yet tried building for Windows, Android, or iOS.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2087593002

Committed: https://skia.googlesource.com/skia/+/1d8de594f126b9a80bd8f8fa2005e90faf3b5b17
Review-Url: https://codereview.chromium.org/2087593002

1 files changed, 37 insertions, 0 deletions

diff --git a/gn.py b/gn.py
new file mode 100755
index 0000000000..b17280a1b1
--- /dev/null
+++ b/gn.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+
+# Copyright 2016 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import subprocess
+import sys
+
+def quiet(*cmd):
+  cmd = ' '.join(cmd).split()
+  subprocess.check_output(cmd)
+
+def loud(*cmd):
+  cmd = ' '.join(cmd).split()
+  ret = subprocess.call(cmd)
+  if ret != 0:
+    sys.exit(ret)
+
+def gn_path():
+  if 'linux' in sys.platform:
+    return 'buildtools/linux64/gn'
+  if 'darwin' in sys.platform:
+    return 'buildtools/mac/gn'
+  return 'buildtools/win/gn.exe'
+
+# Make sure we've got an up-to-date GN and Clang, and sysroot on Linux.
+quiet('download_from_google_storage',
+     '--no_resume --no_auth --bucket chromium-gn',
+     '-s ', gn_path() + '.sha1')
+quiet('python tools/clang/scripts/update.py --if-needed')
+if 'linux' in sys.platform:
+  quiet('python build/linux/sysroot_scripts/install-sysroot.py --arch=amd64')
+
+# Pass all our arguments over to the real GN binary.
+loud(gn_path(), *sys.argv[1:])