[Fuchsia] Add Mac build support.

This adds support to build Chromium for Fuchsia on macOS. Currently,
this configuration is to be treated as best-effort.

CQ_INCLUDE_TRYBOTS=luci.chromium.try:fuchsia_arm64_cast_audio;luci.chromium.try:fuchsia_x64_cast_audio

Bug: 707030
Test: Locally, builds on mac.
Change-Id: I9e4bde1b7ff658f51586856ae80598c93a2b2e33
Reviewed-on: https://chromium-review.googlesource.com/1185020
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#587546}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: bbc67a1bd5cc611039aef8c6a2f9fa7151a07735

config/fuchsia/BUILD.gn

@@ -121,7 +121,7 @@ action("blobstore_extended_qcow2") {
   ]
 
   args = [
-    rebase_path("//third_party/qemu/bin/qemu-img", root_build_dir),
+    rebase_path("${qemu_root}/bin/qemu-img", root_build_dir),
     "convert",
     "-f",
     "raw",

config/fuchsia/config.gni

@@ -17,3 +17,6 @@ if (current_cpu == "arm64") {
 } else {
   assert(false, "No libraries available for architecture: $current_cpu")
 }
+
+# Compute the qemu path.
+qemu_root = "//third_party/qemu-${host_os}-${host_cpu}"

config/fuchsia/rules.gni

@@ -69,7 +69,7 @@ template("fuchsia_package_runner") {
       _manifest_path,
       "//build/fuchsia/",
       "//build/util/lib/",
-      "//third_party/qemu",
+      "${qemu_root}/",
       "${fuchsia_sdk}/",
     ]
 

fuchsia/boot_data.py

@@ -85,7 +85,7 @@ def _MakeQcowDisk(output_dir, disk_path):
   """Creates a QEMU copy-on-write version of |disk_path| in the output
   directory."""
 
-  qimg_path = os.path.join(common.QEMU_ROOT, 'bin', 'qemu-img')
+  qimg_path = os.path.join(common.GetQemuRootForPlatform(), 'bin', 'qemu-img')
   output_path = os.path.join(output_dir,
                              os.path.basename(disk_path) + '.qcow2')
   subprocess.check_call([qimg_path, 'create', '-q', '-f', 'qcow2',

fuchsia/common.py

@@ -3,10 +3,11 @@
 # found in the LICENSE file.
 
 import os
+import platform
+import sys
 
 DIR_SOURCE_ROOT = os.path.abspath(
     os.path.join(os.path.dirname(__file__), os.pardir, os.pardir))
-QEMU_ROOT = os.path.join(DIR_SOURCE_ROOT, 'third_party', 'qemu')
 SDK_ROOT = os.path.join(DIR_SOURCE_ROOT, 'third_party', 'fuchsia-sdk', 'sdk')
 
 def EnsurePathExists(path):
@@ -17,3 +18,24 @@ def EnsurePathExists(path):
     raise IOError('Missing file: ' + path)
 
   return path
+
+def GetHostOsFromPlatform():
+  host_platform = sys.platform
+  if host_platform.startswith('linux'):
+    return 'linux'
+  elif host_platform.startswith('darwin'):
+    return 'mac'
+  raise Exception('Unsupported host platform: %s' % host_platform)
+
+def GetHostArchFromPlatform():
+  host_arch = platform.machine()
+  if host_arch == 'x86_64':
+    return 'x64'
+  elif host_arch == 'aarch64':
+    return 'arm64'
+  raise Exception('Unsupported host architecture: %s' % host_arch)
+
+def GetQemuRootForPlatform():
+  return os.path.join(DIR_SOURCE_ROOT, 'third_party',
+                      'qemu-' + GetHostOsFromPlatform() + '-' +
+                       GetHostArchFromPlatform())

fuchsia/mac.sdk.sha1

@@ -0,0 +1 @@
+61465d3f598a8ad7e6cde3f6505684c63d5361de

fuchsia/qemu_target.py

@@ -14,7 +14,7 @@ import subprocess
 import sys
 import time
 
-from common import QEMU_ROOT, EnsurePathExists
+from common import GetQemuRootForPlatform, EnsurePathExists
 
 
 # Virtual networking configuration data for QEMU.
@@ -57,7 +57,7 @@ class QemuTarget(target.Target):
       self._qemu_process.kill()
 
   def Start(self):
-    qemu_path = os.path.join(QEMU_ROOT, 'bin',
+    qemu_path = os.path.join(GetQemuRootForPlatform(), 'bin',
                              'qemu-system-' + self._GetTargetSdkLegacyArch())
     kernel_args = boot_data.GetKernelArgs(self._output_dir)
 
@@ -100,24 +100,27 @@ class QemuTarget(target.Target):
       ]
 
     # Configure the machine & CPU to emulate, based on the target architecture.
-    # Enable lightweight virtualization (KVM) if the host and guest OS run on
-    # the same architecture.
     if self._target_cpu == 'arm64':
       qemu_command.extend([
           '-machine','virt',
           '-cpu', 'cortex-a53',
       ])
       netdev_type = 'virtio-net-pci'
-      if platform.machine() == 'aarch64':
-        qemu_command.append('-enable-kvm')
     else:
       qemu_command.extend([
           '-machine', 'q35',
-          '-cpu', 'host,migratable=no',
       ])
       netdev_type = 'e1000'
-      if platform.machine() == 'x86_64':
+
+    # On Linux, enable lightweight virtualization (KVM) if the host and guest
+    # architectures are the same.
+    if sys.platform.startswith('linux'):
+      if self._target_cpu == 'arm64' and platform.machine() == 'aarch64':
         qemu_command.append('-enable-kvm')
+      elif self._target_cpu == 'x64' and platform.machine() == 'x86_64':
+        qemu_command.extend([
+            '-enable-kvm', '-cpu', 'host,migratable=no',
+        ])
 
     # Configure virtual network. It is used in the tests to connect to
     # testserver running on the host.

fuchsia/run_package.py

@@ -10,12 +10,13 @@ import json
 import logging
 import multiprocessing
 import os
+import select
 import shutil
 import subprocess
+import sys
 import tempfile
 import threading
 import uuid
-import select
 
 from symbolizer import FilterStream
 
@@ -40,47 +41,33 @@ def _ReadMergedLines(streams):
   signals EOF. Absolute output ordering is not guaranteed."""
 
   assert len(streams) > 0
-  poll = select.poll()
   streams_by_fd = {}
   primary_fd = streams[0].fileno()
   for s in streams:
-    poll.register(s.fileno(), select.POLLIN)
     streams_by_fd[s.fileno()] = s
 
-  try:
-    while primary_fd != None:
-      events = poll.poll(1)
-      for fileno, event in events:
-        if event & select.POLLIN:
-          yield streams_by_fd[fileno].readline()
-
-        elif event & select.POLLHUP:
-          poll.unregister(fileno)
-          del streams_by_fd[fileno]
-
-          if fileno == primary_fd:
-            primary_fd = None
-  finally:
-    for fd_to_cleanup, _ in streams_by_fd.iteritems():
-      poll.unregister(fd_to_cleanup)
+  while primary_fd != None:
+    rlist, _, _ = select.select(streams_by_fd, [], [], 0.1)
+    for fileno in rlist:
+      line = streams_by_fd[fileno].readline()
+      if line:
+        yield line
+      elif fileno == primary_fd:
+        primary_fd = None
+      else:
+        del streams_by_fd[fileno]
 
 
 def DrainStreamToStdout(stream, quit_event):
   """Outputs the contents of |stream| until |quit_event| is set."""
 
-  poll = select.poll()
-  poll.register(stream.fileno(), select.POLLIN)
-  try:
-    while not quit_event.is_set():
-      events = poll.poll(1)
-      for fileno, event in events:
-        if event & select.POLLIN:
-          print stream.readline().rstrip()
-        elif event & select.POLLHUP:
-          break
-
-  finally:
-    poll.unregister(stream.fileno())
+  while not quit_event.is_set():
+    rlist, _, _ = select.select([ stream ], [], [], 0.1)
+    if rlist:
+      line = rlist[0].readline()
+      if not line:
+        return
+      print line.rstrip()
 
 
 def RunPackage(output_dir, target, package_path, package_name, package_deps,

fuchsia/update_sdk.py

@@ -13,7 +13,7 @@ import sys
 import tarfile
 import tempfile
 
-SDK_HASH_FILE = os.path.join(os.path.dirname(__file__), 'sdk.sha1')
+from common import GetHostOsFromPlatform, GetHostArchFromPlatform
 
 REPOSITORY_ROOT = os.path.abspath(os.path.join(
     os.path.dirname(__file__), '..', '..'))
@@ -24,6 +24,16 @@ import find_depot_tools
 SDK_SUBDIRS = ["arch", "pkg", "qemu", "sysroot", "target",
                "toolchain_libs", "tools"]
 
+def GetSdkHashForPlatform():
+  if sys.platform.startswith('darwin'):
+    return os.path.join(os.path.dirname(__file__), 'mac.sdk.sha1')
+  else:
+    return os.path.join(os.path.dirname(__file__), 'sdk.sha1')
+
+def GetBucketForPlatform():
+  return 'gs://fuchsia/sdk/{platform}-amd64/'.format(
+      platform = GetHostOsFromPlatform())
+
 
 def EnsureDirExists(path):
   if not os.path.exists(path):
@@ -63,11 +73,12 @@ def main():
   # there.
   Cleanup(os.path.join(REPOSITORY_ROOT, 'third_party', 'fuchsia-sdk'))
 
-  with open(SDK_HASH_FILE, 'r') as f:
+  hash_file = GetSdkHashForPlatform()
+  with open(hash_file, 'r') as f:
     sdk_hash = f.read().strip()
 
   if not sdk_hash:
-    print >>sys.stderr, 'No SHA1 found in %s' % SDK_HASH_FILE
+    print >>sys.stderr, 'No SHA1 found in %s' % hash_file
     return 1
 
   output_dir = os.path.join(REPOSITORY_ROOT, 'third_party', 'fuchsia-sdk',
@@ -89,9 +100,8 @@ def main():
   os.close(fd)
 
   try:
-    bucket = 'gs://fuchsia/sdk/linux-amd64/'
     cmd = [os.path.join(find_depot_tools.DEPOT_TOOLS_PATH, 'gsutil.py'),
-           'cp', bucket + sdk_hash, tmp]
+           'cp', GetBucketForPlatform() + sdk_hash, tmp]
     subprocess.check_call(cmd)
     with open(tmp, 'rb') as f:
       EnsureDirExists(output_dir)

toolchain/fuchsia/BUILD.gn

@@ -9,14 +9,17 @@ import("//build/config/fuchsia/config.gni")
 # the different target architectures.
 template("fuchsia_clang_toolchain") {
   clang_toolchain(target_name) {
-    assert(host_os == "linux")
+    assert(host_os == "linux" || host_os == "mac")
     assert(defined(invoker.toolchain_args),
            "toolchain_args must be defined for fuchsia_clang_toolchain()")
 
     # We want to build and strip binaries, but retain the unstripped binaries
     # in runtime_deps to make them available for isolates.
-    strip = rebase_path("//third_party/eu-strip/bin/eu-strip", root_build_dir)
-    use_unstripped_as_runtime_outputs = true
+    # TODO(https://crbug.com/877080): Switch to llvm-strip.
+    if (host_os == "linux") {
+      strip = rebase_path("//third_party/eu-strip/bin/eu-strip", root_build_dir)
+      use_unstripped_as_runtime_outputs = true
+    }
 
     toolchain_args = invoker.toolchain_args
     toolchain_args.current_os = "fuchsia"