Bug 1207897 - Add a configure option to build multiple build backends. r=gps

Also record what backends were requested at configure time so that running
`mach build-backend` or `config.status` uses the same set.

build/autoconf/config.status.m4

@@ -222,3 +222,15 @@ MOZ_RUN_CONFIG_STATUS()],
 define([AC_CONFIG_HEADER],
 [m4_fatal([Use CONFIGURE_DEFINE_FILES in moz.build files to produce header files.])
 ])
+
+define([MOZ_BUILD_BACKEND],
+[
+BUILD_BACKENDS="RecursiveMake"
+
+MOZ_ARG_ENABLE_STRING(build-backend,
+[  --enable-build-backend={AndroidEclipse,CppEclipse,VisualStudio,FasterMake}
+                         Enable additional build backends],
+[ BUILD_BACKENDS="RecursiveMake `echo $enableval | sed 's/,/ /g'`"])
+
+AC_SUBST_LIST([BUILD_BACKENDS])
+])

configure.in

@@ -137,6 +137,8 @@ MOZ_BUILD_ROOT=`pwd -W 2>/dev/null || pwd`
 
 MOZ_PYTHON
 
+MOZ_BUILD_BACKEND
+
 MOZ_DEFAULT_COMPILER
 
 COMPILE_ENVIRONMENT=1

js/src/configure.in

@@ -125,6 +125,8 @@ MOZ_ARG_WITH_STRING(dist-dir,
     TOP_DIST=dist)
 AC_SUBST(TOP_DIST)
 
+MOZ_BUILD_BACKEND
+
 MOZ_DEFAULT_COMPILER
 
 COMPILE_ENVIRONMENT=1

python/mozbuild/mozbuild/config_status.py

@@ -88,6 +88,15 @@ def config_status(topobjdir='.', topsrcdir='.',
         raise Exception('topsrcdir must be defined as an absolute directory: '
             '%s' % topsrcdir)
 
+    default_backends = ['RecursiveMake']
+    # We have a chicken/egg problem, where we only have a dict for substs after
+    # creating the ConfigEnvironment, which requires argument parsing to have
+    # occurred.
+    for name, value in substs:
+        if name == 'BUILD_BACKENDS':
+            default_backends = value
+            break
+
     parser = ArgumentParser()
     parser.add_argument('--recheck', dest='recheck', action='store_true',
                         help='update config.status by reconfiguring in the same conditions')
@@ -100,8 +109,9 @@ def config_status(topobjdir='.', topsrcdir='.',
     parser.add_argument('-b', '--backend', nargs='+',
                         choices=['RecursiveMake', 'AndroidEclipse', 'CppEclipse',
                                  'VisualStudio', 'FasterMake'],
-                        default=['RecursiveMake'],
-                        help='what backend to build (default: RecursiveMake).')
+                        default=default_backends,
+                        help='what backend to build (default: %s).' %
+                        ' '.join(default_backends))
     options = parser.parse_args()
 
     # Without -n, the current directory is meant to be the top object directory

python/mozbuild/mozbuild/mach_commands.py

@@ -561,9 +561,8 @@ class Build(MachCommandBase):
     @CommandArgument('-b', '--backend', nargs='+',
         choices=['RecursiveMake', 'AndroidEclipse', 'CppEclipse',
                  'VisualStudio', 'FasterMake'],
-        default=['RecursiveMake'],
-        help='Which backend to build (default: RecursiveMake).')
-    def build_backend(self, backend='RecursiveMake', diff=False):
+        help='Which backend to build.')
+    def build_backend(self, backend, diff=False):
         python = self.virtualenv_manager.python_path
         config_status = os.path.join(self.topobjdir, 'config.status')
 
@@ -573,7 +572,10 @@ class Build(MachCommandBase):
                   % backend)
             return 1
 
-        args = [python, config_status, '--backend'] + backend
+        args = [python, config_status]
+        if backend:
+            args.append('--backend')
+            args.extend(backend)
         if diff:
             args.append('--diff')