Add clang frontend arguments to the xcodebuild module

Summary:
@public
This will enable support for the same set of arguments already supported by the `make` module, e.g. `--frontend-stats`, `--frontend-debug`

Test Plan:
Tested on an Xcode project with the `-fs` argument, and checked that `.astlog` files have been generated on the same location of the .o files
  infer -fs -- xcodebuild -workspace Project.xcworkspace -scheme Project -sdk iphonesimulator

infer/lib/capture/make.py

@@ -1,8 +1,9 @@
-import argparse
 import os
 import subprocess
 import traceback
 
+import util
+
 MODULE_NAME = 'make/cc/clang/gcc'
 MODULE_DESCRIPTION = '''Run analysis of code built with commands like:
 make [target]
@@ -24,51 +25,8 @@ def mkdir_if_not_exists(path):
     if not os.path.exists(path):
         os.mkdir(path)
 
-
-def create_argparser(group_name=MODULE_NAME):
-    """This defines the set of arguments that get added by this module to the
-    set of global args defined in the infer top-level module
-    Do not use this function directly, it should be invoked by the infer
-    top-level module"""
-    parser = argparse.ArgumentParser(add_help=False)
-    group = parser.add_argument_group(
-        "{grp} module".format(grp=MODULE_NAME),
-        description=MODULE_DESCRIPTION,
-    )
-    group.add_argument(
-        '-hd', '--headers',
-        action='store_true',
-        help='Analyze code in header files',
-    )
-    group.add_argument(
-        '--models_mode',
-        action='store_true',
-        dest='models_mode',
-        help='Mode for computing the models',
-    )
-    group.add_argument(
-        '--no_failures_allowed',
-        action='store_true',
-        dest='no_failures_allowed',
-        help='Fail if at least one of the translations fails',
-    )
-    group.add_argument(
-        '-tm', '--testing_mode',
-        dest='testing_mode',
-        action='store_true',
-        help='Testing mode for the translation: Do not translate libraries'
-             ' (including enums)')
-    group.add_argument(
-        '-fs', '--frontend-stats',
-        dest='frontend_stats',
-        action='store_true',
-        help='Output statistics about the capture phase to *.o.astlog')
-    group.add_argument(
-        '-fd', '--frontend-debug',
-        dest='frontend_debug',
-        action='store_true',
-        help='Output debugging information to *.o.astlog during capture')
-    return parser
+create_argparser = \
+    util.clang_frontend_argparser(MODULE_DESCRIPTION, MODULE_NAME)
 
 
 class MakeCapture:
@@ -85,45 +43,25 @@ class MakeCapture:
 
     def get_envvars(self):
         env_vars = dict(os.environ)
-        env_vars['INFER_RESULTS_DIR'] = self.args.infer_out
         wrappers_path = os.path.join(
-            os.path.dirname(os.path.realpath(__file__)), '..', 'wrappers')
+            os.path.dirname(
+                os.path.realpath(__file__)), os.path.pardir, 'wrappers')
         env_vars['INFER_OLD_PATH'] = env_vars['PATH']
         env_vars['PATH'] = '{wrappers}{sep}{path}'.format(
             wrappers=wrappers_path,
             sep=os.pathsep,
             path=env_vars['PATH'],
         )
+
+        frontend_env_vars = util.get_clang_frontend_envvars(self.args)
+        env_vars.update(frontend_env_vars)
         return env_vars
 
     def capture(self):
         self.create_results_dir()
 
-        env_vars = self.get_envvars()
-        frontend_args = []
-
-        if self.args.headers:
-            frontend_args.append('-headers')
-        if self.args.models_mode:
-            frontend_args.append('-models_mode')
-        if self.args.project_root:
-            frontend_args += ['-project_root', self.args.project_root]
-        if self.args.testing_mode:
-            frontend_args.append('-testing_mode')
-        if self.args.frontend_debug:
-            frontend_args += ['-debug']
-            env_vars['FCP_DEBUG_MODE'] = '1'
-        if self.args.frontend_stats:
-            frontend_args += ['-stats']
-            env_vars['FCP_DEBUG_MODE'] = '1'
-        if self.args.no_failures_allowed:
-            env_vars['FCP_REPORT_FRONTEND_FAILURE'] = '1'
-
-        # export an env variable with all the arguments to pass to InferClang
-        env_vars['FCP_INFER_FRONTEND_ARGS'] = ' '.join(frontend_args)
-
         try:
-            subprocess.check_call(self.cmd, env=env_vars)
+            subprocess.check_call(self.cmd, env=self.get_envvars())
             return os.EX_OK
         except subprocess.CalledProcessError as exc:
             if self.args.debug:

infer/lib/capture/util.py

@@ -47,3 +47,79 @@ def base_argparser(description, module_name):
         )
         return parser
     return _func
+
+
+def clang_frontend_argparser(description, module_name):
+    def _func(group_name=module_name):
+        """This creates an argparser for all the modules that require
+        clang for their capture phase, thus InferClang and clang wrappers"""
+        parser = argparse.ArgumentParser(add_help=False)
+        group = parser.add_argument_group(
+            "{grp} module".format(grp=group_name),
+            description=description,
+        )
+        group.add_argument(
+            '-hd', '--headers',
+            action='store_true',
+            help='Analyze code in header files',
+        )
+        group.add_argument(
+            '--models_mode',
+            action='store_true',
+            dest='models_mode',
+            help='Mode for computing the models',
+        )
+        group.add_argument(
+            '--no_failures_allowed',
+            action='store_true',
+            dest='no_failures_allowed',
+            help='Fail if at least one of the translations fails',
+        )
+        group.add_argument(
+            '-tm', '--testing_mode',
+            dest='testing_mode',
+            action='store_true',
+            help='Testing mode for the translation: Do not translate libraries'
+                 ' (including enums)')
+        group.add_argument(
+            '-fs', '--frontend-stats',
+            dest='frontend_stats',
+            action='store_true',
+            help='Output statistics about the capture phase to *.o.astlog')
+        group.add_argument(
+            '-fd', '--frontend-debug',
+            dest='frontend_debug',
+            action='store_true',
+            help='Output debugging information to *.o.astlog during capture')
+        return parser
+    return _func
+
+
+def get_clang_frontend_envvars(args):
+    """Return the environment variables that configure the clang wrapper, e.g.
+    to emit debug information if needed, and the invocation of the Infer
+    frontend for Clang, InferClang, e.g. to analyze headers, emit stats, etc"""
+    env_vars = {}
+    frontend_args = []
+
+    env_vars['INFER_RESULTS_DIR'] = args.infer_out
+    if args.headers:
+        frontend_args.append('-headers')
+    if args.models_mode:
+        frontend_args.append('-models_mode')
+    if args.project_root:
+        frontend_args += ['-project_root', args.project_root]
+    if args.testing_mode:
+        frontend_args.append('-testing_mode')
+    if args.frontend_debug:
+        frontend_args += ['-debug']
+        env_vars['FCP_DEBUG_MODE'] = '1'
+    if args.frontend_stats:
+        frontend_args += ['-stats']
+        env_vars['FCP_DEBUG_MODE'] = '1'
+    if args.no_failures_allowed:
+        env_vars['FCP_REPORT_FRONTEND_FAILURE'] = '1'
+
+    # export an env variable with all the arguments to pass to InferClang
+    env_vars['FCP_INFER_FRONTEND_ARGS'] = ' '.join(frontend_args)
+    return env_vars

infer/lib/capture/xcodebuild.py

@@ -25,9 +25,8 @@ CLANGPLUSPLUS_WRAPPER = os.path.join(
 def gen_instance(*args):
     return XcodebuildCapture(*args)
 
-# This creates an empty argparser for the module, which provides only
-# description/usage information and no arguments.
-create_argparser = util.base_argparser(MODULE_DESCRIPTION, MODULE_NAME)
+create_argparser = \
+    util.clang_frontend_argparser(MODULE_DESCRIPTION, MODULE_NAME)
 
 
 class XcodebuildCapture:
@@ -35,14 +34,20 @@ class XcodebuildCapture:
         self.args = args
         self.cmd = cmd
 
-    def capture(self):
+    def get_envvars(self):
         env_vars = dict(os.environ)
 
-        # get the path to 'true' using xcrun
-        true_path = subprocess.check_output(['xcrun', '--find', 'true']).strip()
         apple_clang_path = \
             subprocess.check_output(['xcrun', '--find', 'clang']).strip()
 
+        env_vars['FCP_APPLE_CLANG'] = apple_clang_path
+
+        frontend_env_vars = \
+            util.get_clang_frontend_envvars(self.args)
+        env_vars.update(frontend_env_vars)
+        return env_vars
+
+    def capture(self):
         # these settings will instruct xcodebuild on which clang to use
         self.cmd += ['CC={wrapper}'.format(wrapper=CLANG_WRAPPER)]
         self.cmd += ['CPLUSPLUS={wrapper}'.format(wrapper=CLANGPLUSPLUS_WRAPPER)]
@@ -52,11 +57,8 @@ class XcodebuildCapture:
         # the open-source one
         self.cmd += ['GCC_PRECOMPILE_PREFIX_HEADER=NO']
 
-        env_vars['INFER_RESULTS_DIR'] = self.args.infer_out
-        env_vars['FCP_APPLE_CLANG'] = apple_clang_path
-
         try:
-            subprocess.check_call(self.cmd, env=env_vars)
+            subprocess.check_call(self.cmd, env=self.get_envvars())
             return os.EX_OK
         except subprocess.CalledProcessError as exc:
             if self.args.debug: