mac ninja and make: Add support for GCC_ENABLE_OBJC_GC.

pylib/gyp/xcode_emulation.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.
 
 """
 This module contains classes that help to emulate xcodebuild behavior on top of
 other build systems, such as make and ninja.
 """
 
 import gyp.common
@@ skipping 288 matching lines @@
     if self._Test('GCC_WARN_ABOUT_MISSING_NEWLINE', 'YES', default='NO'):
       cflags.append('-Wnewline-eof')
 
     self._Appendf(cflags, 'MACOSX_DEPLOYMENT_TARGET', '-mmacosx-version-min=%s')
 
     # TODO:
     if self._Test('COPY_PHASE_STRIP', 'YES', default='NO'):
       self._WarnUnimplemented('COPY_PHASE_STRIP')
     self._WarnUnimplemented('GCC_DEBUGGING_SYMBOLS')
     self._WarnUnimplemented('GCC_ENABLE_OBJC_EXCEPTIONS')
-    self._WarnUnimplemented('GCC_ENABLE_OBJC_GC')
 
     # TODO: This is exported correctly, but assigning to it is not supported.
     self._WarnUnimplemented('MACH_O_TYPE')
     self._WarnUnimplemented('PRODUCT_TYPE')
 
     archs = self._Settings().get('ARCHS', ['i386'])
     if len(archs) != 1:
       # TODO: Supporting fat binaries will be annoying.
       self._WarnUnimplemented('ARCHS')
       archs = ['i386']
@@ skipping 50 matching lines @@
         flag = '$OTHER_CFLAGS'
       if flag in ('$OTHER_CFLAGS', '$(OTHER_CFLAGS)', '${OTHER_CFLAGS}'):
         other_ccflags += self._Settings().get('OTHER_CFLAGS', [])
       else:
         other_ccflags.append(flag)
     cflags_cc += other_ccflags
 
     self.configname = None
     return cflags_cc
 
+  def _AddObjectiveCGarbageCollectionFlags(self, flags):
+    gc_policy = self._Settings().get('GCC_ENABLE_OBJC_GC', 'unsupported')
+    if gc_policy == 'supported':
+      flags.append('-fobjc-gc')
+    elif gc_policy == 'required':
+      flags.append('-fobjc-gc-only')
+
   def GetCflagsObjC(self, configname):
     """Returns flags that need to be added to .m compilations."""
     self.configname = configname
+    cflags_objc = []
+
+    self._AddObjectiveCGarbageCollectionFlags(cflags_objc)
+
     self.configname = None
-    return []
+    return cflags_objc
 
   def GetCflagsObjCC(self, configname):
     """Returns flags that need to be added to .mm compilations."""
     self.configname = configname
     cflags_objcc = []
+    self._AddObjectiveCGarbageCollectionFlags(cflags_objcc)
     if self._Test('GCC_OBJC_CALL_CXX_CDTORS', 'YES', default='NO'):
       cflags_objcc.append('-fobjc-call-cxx-cdtors')
     self.configname = None
     return cflags_objcc
 
   def GetInstallNameBase(self):
     """Return DYLIB_INSTALL_NAME_BASE for this target."""
     # Xcode sets this for shared_libraries, and for nonbundled loadable_modules.
     if (self.spec['type'] != 'shared_library' and
         (self.spec['type'] != 'loadable_module' or self._IsBundle())):
@@ skipping 608 matching lines @@
 def GetSpecPostbuildCommands(spec, quiet=False):
   """Returns the list of postbuilds explicitly defined on |spec|, in a form
   executable by a shell."""
   postbuilds = []
   for postbuild in spec.get('postbuilds', []):
     if not quiet:
       postbuilds.append('echo POSTBUILD\\(%s\\) %s' % (
             spec['target_name'], postbuild['postbuild_name']))
     postbuilds.append(gyp.common.EncodePOSIXShellList(postbuild['action']))
   return postbuilds