Enable cross-compilation with ninja.

pylib/gyp/generator/ninja.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import copy
 import gyp
 import gyp.common
 import gyp.msvs_emulation
 import gyp.system_test
 import gyp.xcode_emulation
@@ skipping 26 matching lines @@
   # Special variables that may be used by gyp 'rule' targets.
   # We generate definitions for these variables on the fly when processing a
   # rule.
   'RULE_INPUT_ROOT': '${root}',
   'RULE_INPUT_DIRNAME': '${dirname}',
   'RULE_INPUT_PATH': '${source}',
   'RULE_INPUT_EXT': '${ext}',
   'RULE_INPUT_NAME': '${name}',
 }
 
-# TODO: enable cross compiling once we figure out:
-# - how to not build extra host objects in the non-cross-compile case.
-# - how to decide what the host compiler is (should not just be $cc).
-# - need ld_host as well.
-generator_supports_multiple_toolsets = False
+# TODO: figure out how to not build extra host objects in the non-cross-compile
+# case when this is enabled, and enable unconditionally.
+generator_supports_multiple_toolsets = (
+  os.environ.get('AR_target') or os.environ.get('CC_target') or
+  os.environ.get('CXX_target'))
 
 
 def StripPrefix(arg, prefix):
   if arg.startswith(prefix):
     return arg[len(prefix):]
   return arg
 
 def QuoteShellArgument(arg, flavor):
   """Quote a string such that it will be interpreted as a single argument
   by the shell."""
@@ skipping 508 matching lines @@
     env = self.ComputeExportEnvString(env)
 
     self.ninja.build(out, 'mac_tool', info_plist,
                      variables=[('mactool_cmd', 'copy-info-plist'),
                                 ('env', env)])
     bundle_depends.append(out)
 
   def WriteSources(self, config_name, config, sources, predepends,
                    precompiled_header):
     """Write build rules to compile all of |sources|."""
-    if self.toolset == 'host':
-      self.ninja.variable('cc', '$cc_host')
-      self.ninja.variable('cxx', '$cxx_host')
+    if self.toolset == 'target':
+      self.ninja.variable('ar', '$ar_target')
+      self.ninja.variable('cc', '$cc_target')
+      self.ninja.variable('cxx', '$cxx_target')
+      self.ninja.variable('ld', '$ld_target')
 
     if self.flavor == 'mac':
       cflags = self.xcode_settings.GetCflags(config_name)
       cflags_c = self.xcode_settings.GetCflagsC(config_name)
       cflags_cc = self.xcode_settings.GetCflagsCC(config_name)
       cflags_objc = ['$cflags_c'] + \
                     self.xcode_settings.GetCflagsObjC(config_name)
       cflags_objcc = ['$cflags_cc'] + \
                      self.xcode_settings.GetCflagsObjCC(config_name)
     else:
@@ skipping 462 matching lines @@
   build_file, _, _ = gyp.common.ParseQualifiedTarget(target_list[0])
   make_global_settings = data[build_file].get('make_global_settings', [])
   build_to_root = InvertRelativePath(build_dir)
   for key, value in make_global_settings:
     if key == 'CC': cc = os.path.join(build_to_root, value)
     if key == 'CXX': cxx = os.path.join(build_to_root, value)
 
   flock = 'flock'
   if flavor == 'mac':
     flock = './gyp-mac-tool flock'
+  master_ninja.variable('ar', os.environ.get('AR', 'ar'))
   master_ninja.variable('cc', os.environ.get('CC', cc))
   master_ninja.variable('cxx', os.environ.get('CXX', cxx))
   if flavor == 'win':
     master_ninja.variable('ld', 'link')
   else:
     master_ninja.variable('ld', flock + ' linker.lock $cxx')
-  master_ninja.variable('cc_host', '$cc')
-  master_ninja.variable('cxx_host', '$cxx')
+
+  master_ninja.variable('ar_target', os.environ.get('AR_target', '$ar'))

[Ami GONE FROM CHROMIUM, 2012/02/22 22:18:54]

PS#2 just makes the changes in these three lines, which de-break hard-coding the
$PATH-resolved path of, e.g., clang.

(symptom was goma+clang would make machine crawl launching hundreds of local
clang's, in the non-cross-compile case; tested this works in both cross-compiled
& non-cross-compiled cases).

+  master_ninja.variable('cc_target', os.environ.get('CC_target', '$cc'))
+  master_ninja.variable('cxx_target', os.environ.get('CXX_target', '$cxx'))
+  if flavor == 'win':
+    master_ninja.variable('ld_target', 'link')
+  else:
+    master_ninja.variable('ld_target', flock + ' linker.lock $cxx_target')
+
   if flavor == 'mac':
     master_ninja.variable('mac_tool', os.path.join('.', 'gyp-mac-tool'))
   master_ninja.newline()
 
   if flavor != 'win':
     master_ninja.rule(
       'cc',
       description='CC $out',
       command=('$cc -MMD -MF $out.d $defines $includes $cflags $cflags_c '
               '$cflags_pch_c -c $in -o $out'),
@@ skipping 21 matching lines @@
       command=('cmd /c $cxx /nologo /showIncludes '
                '$defines $includes $cflags $cflags_cc '
                '$cflags_pch_cc /c $in /Fo$out '
                '| ninja-deplist-helper -f cl -o $out.dl'),
       deplist='$out.dl')
 
   if flavor != 'mac' and flavor != 'win':
     master_ninja.rule(
       'alink',
       description='AR $out',
-      command='rm -f $out && ar rcsT $out $in')
+      command='rm -f $out && $ar rcsT $out $in')
     master_ninja.rule(
       'solink',
       description='SOLINK $out',
       command=('$ld -shared $ldflags -o $out -Wl,-soname=$soname '
                '-Wl,--whole-archive $in -Wl,--no-whole-archive $libs'))
     master_ninja.rule(
       'solink_module',
       description='SOLINK(module) $out',
       command=('$ld -shared $ldflags -o $out -Wl,-soname=$soname '
                '-Wl,--start-group $in -Wl,--end-group $libs'))
@@ skipping 139 matching lines @@
 
   user_config = params.get('generator_flags', {}).get('config', None)
   if user_config:
     GenerateOutputForConfig(target_list, target_dicts, data, params,
                             user_config)
   else:
     config_names = target_dicts[target_list[0]]['configurations'].keys()
     for config_name in config_names:
       GenerateOutputForConfig(target_list, target_dicts, data, params,
                               config_name)