Re-enable Objective C and Objective C++ support.

This required the following changes:
  - Compute the default search paths for each language lazily,
    when the language is first encountered, rather than
    computing it for 'c' and 'c++'.
  - Make the tests of Objective C and Objective C++
    conditional on the relevant compiler being installed.

Tested by "make check" on two systems:
  - One with Objective C installed, but not Objective C++.
  - One with neither installed.
I didn't test on a system with Objective C++ installed,
because I didn't have one easily available.

Reviewers: Craig Silverstein, Nils Klarlund.

4 files changed, 26 insertions, 31 deletions

diff --git a/include_server/basics.py b/include_server/basics.py
index e86b218..536e0e9 100755
--- a/include_server/basics.py
+++ b/include_server/basics.py
@@ -235,17 +235,7 @@ BAD_REALPATH_WARNING_MSG = (
 # LANGUAGES AND FILE EXTENSIONS
 
 # The languages that we recognize.
-#
-# TODO(klarlund): add "objective-c" and "objective-c++".  Currently we try to
-# compute the default include path for all languages at startup, and barf if it
-# fails.  We need to fix that before enabling objective-c or objective-c++.  So
-# Objective C and Objective C++ support is disabled for now.
-#
-# To enable, uncomment the code below and the test case
-# ObjectiveC(PlusPlus)_Case in ../test/testdistcc.py.)
-
-LANGUAGES = set(['c', 'c++'])
-#LANGUAGES = set(['c', 'c++', 'objective-c', 'objective-c++'])
+LANGUAGES = set(['c', 'c++', 'objective-c', 'objective-c++'])
 
 # The suffixes, following last period, used for source files and
 # preprocessed files, each with their corresponding source language.
@@ -256,9 +246,9 @@ TRANSLATION_UNIT_MAP = {
     'cc': 'c++', 'cpp': 'c++', 'cxx': 'c++', 'C': 'c++', 'CXX': 'c++',
     'ii': 'c++',
     # Objective C
-    # 'm': 'objective-c', 'mi': 'objective-c'
+    'm': 'objective-c', 'mi': 'objective-c',
     # Objective C++
-    # 'mm': 'objective-c++', 'M': 'objective-c++', 'mii': 'objective-c++',
+    'mm': 'objective-c++', 'M': 'objective-c++', 'mii': 'objective-c++',
     }
 
 # All languages are described by suffixes.
diff --git a/include_server/compiler_defaults.py b/include_server/compiler_defaults.py
index 62095d3..02a323b 100755
--- a/include_server/compiler_defaults.py
+++ b/include_server/compiler_defaults.py
@@ -151,11 +151,12 @@ class CompilerDefaults(object):
     self.system_dirs_default = {}
 
 
-  def SetSystemDirsDefaults(self, compiler, timer=None):
+  def SetSystemDirsDefaults(self, compiler, language, timer=None):
     """Set instance variables according to compiler.
 
     Arguments:
-      compiler: a string "c", "c++",...
+      compiler: a filepath (the first argument on the distcc command line)
+      language: 'c' or 'c++' or other item in basics.LANGUAGES
       timer: a basis.IncludeAnalyzerTimer or None
 
     The timer will be disabled during this routine because the select involved
@@ -164,23 +165,26 @@ class CompilerDefaults(object):
     See also the constructor documentation for this class.
     """
     assert isinstance(compiler, str)
-    Debug(DEBUG_TRACE, "SetSystemDirsDefauls with CC: %s" % compiler)
-    if compiler in self.system_dirs_default: return
+    assert isinstance(language, str)
+    Debug(DEBUG_TRACE, "SetSystemDirsDefaults with CC, LANG: %s, %s" %
+                       (compiler, language))
+    if compiler in self.system_dirs_default:
+      if language in self.system_dirs_default[compiler]:
+        return
+    else:
+      self.system_dirs_default[compiler] = {}
     try:
       if timer:
         # We have to disable the timer because the select system call that is
         # executed when calling the compiler through Popen gives up if presented
         # with a SIGALRM.
         timer.Stop()
-      self.system_dirs_default[compiler] = {}
-      # Try 'c', 'c++', ...
-      for language in basics.LANGUAGES:
-        self.system_dirs_default[compiler][language] = (
-          _SystemSearchdirsGCC(compiler, language, self.canonical_lookup))
-        Debug(DEBUG_DATA,
-              "system_dirs_default[%s][%s]: %s" %
-              (compiler, language,
-               self.system_dirs_default[compiler][language]))
+      self.system_dirs_default[compiler][language] = (
+        _SystemSearchdirsGCC(compiler, language, self.canonical_lookup))
+      Debug(DEBUG_DATA,
+            "system_dirs_default[%s][%s]: %s" %
+            (compiler, language,
+             self.system_dirs_default[compiler][language]))
       # Now summarize what we know and add to system_dirs_default_all.
       self.system_dirs_default_all |= set(
         [ _default
diff --git a/include_server/parse_command.py b/include_server/parse_command.py
index 1a5fcc3..eab51b9 100755
--- a/include_server/parse_command.py
+++ b/include_server/parse_command.py
@@ -425,10 +425,11 @@ def ParseCommandArgs(args, current_dir, fp_map, dir_map, compiler_defaults,
     if not language_match:
       raise NotCoveredError(
           "For source file '%s': unrecognized filename extension" % source_file)
-    parse_state.language = language_match.group('suffix')
-  assert parse_state.language in basics.TRANSLATION_UNIT_MAP
+    suffix = language_match.group('suffix')
+    parse_state.language = basics.TRANSLATION_UNIT_MAP[suffix]
+  assert parse_state.language in basics.LANGUAGES
 
-  compiler_defaults.SetSystemDirsDefaults(compiler, timer)
+  compiler_defaults.SetSystemDirsDefaults(compiler, parse_state.language, timer)
 
   def IndexDirs(dir_list):
     """Normalize directory names and index.
@@ -446,7 +447,7 @@ def ParseCommandArgs(args, current_dir, fp_map, dir_map, compiler_defaults,
   if not parse_state.nostdinc:
     angle_dirs.extend(
       IndexDirs(compiler_defaults.system_dirs_default
-                [compiler][basics.TRANSLATION_UNIT_MAP[parse_state.language]]))
+                [compiler][parse_state.language]))
   angle_dirs.extend(IndexDirs(parse_state.after_system_dirs))
 
   quote_dirs = IndexDirs(parse_state.quote_dirs)
diff --git a/include_server/parse_command_test.py b/include_server/parse_command_test.py
index fd5db01..2e754e3 100755
--- a/include_server/parse_command_test.py
+++ b/include_server/parse_command_test.py
@@ -47,7 +47,7 @@ class ParseCommandUnitTest(unittest.TestCase):
     mock_compiler = '/usr/crosstool/v8/gcc-4.1.0-glibc-2.2.2/blah/gcc'
     self.mock_compiler = mock_compiler
 
-    def Mock_SetSystemDirsDefaults(compiler, timer=None):
+    def Mock_SetSystemDirsDefaults(compiler, language, timer=None):
       if compiler != mock_compiler:
         raise Exception, "compiler: %s, mock_compiler: %s" % (
           compiler, mock_compiler)