Auto merge of #276 - d0k:argv0, r=Valloric

Pass full argv to libclang, including argv[0]

Pass full argv to libclang, including argv[0]. Fixes some long standing issues with finding the standard library on some configurations when using compilation databases.

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/valloric/ycmd/276)
<!-- Reviewable:end -->

cpp/ycm/ClangCompleter/TranslationUnit.cpp

@@ -35,7 +35,7 @@ namespace YouCompleteMe {
 
 namespace {
 
-unsigned editingOptions() {
+unsigned EditingOptions() {
   return CXTranslationUnit_DetailedPreprocessingRecord |
          CXTranslationUnit_Incomplete |
          CXTranslationUnit_IncludeBriefCommentsInCodeCompletion |
@@ -44,16 +44,23 @@ unsigned editingOptions() {
          clang_defaultEditingTranslationUnitOptions();
 }
 
-unsigned reparseOptions( CXTranslationUnit translationUnit ) {
+unsigned ReparseOptions( CXTranslationUnit translationUnit ) {
     return clang_defaultReparseOptions( translationUnit );
 }
 
 
-unsigned completionOptions() {
+unsigned CompletionOptions() {
   return clang_defaultCodeCompleteOptions() |
          CXCodeComplete_IncludeBriefComments;
 }
 
+void EnsureCompilerNamePresent( std::vector< const char * > &flags ) {
+  bool no_compiler_name_set = !flags.empty() && flags.front()[ 0 ] == '-';
+
+  if ( flags.empty() || no_compiler_name_set )
+    flags.insert( flags.begin(), "clang" );
+}
+
 }  // unnamed namespace
 
 typedef shared_ptr <
@@ -78,21 +85,27 @@ TranslationUnit::TranslationUnit(
     pointer_flags.push_back( flag.c_str() );
   }
 
+  EnsureCompilerNamePresent( pointer_flags );
+
   std::vector< CXUnsavedFile > cxunsaved_files =
     ToCXUnsavedFiles( unsaved_files );
   const CXUnsavedFile *unsaved = cxunsaved_files.size() > 0
                                  ? &cxunsaved_files[ 0 ] : NULL;
 
-  clang_translation_unit_ = clang_parseTranslationUnit(
-                              clang_index,
-                              filename.c_str(),
-                              &pointer_flags[ 0 ],
-                              pointer_flags.size(),
-                              const_cast<CXUnsavedFile *>( unsaved ),
-                              cxunsaved_files.size(),
-                              editingOptions() );
-
-  if ( !clang_translation_unit_ )
+  // Actually parse the translation unit.
+  // TODO: Stop stripping argv[0] here and use
+  // clang_parseTranslationUnit2FullArgv, which is available in libclang 3.8.
+  CXErrorCode result = clang_parseTranslationUnit2(
+                         clang_index,
+                         filename.c_str(),
+                         &pointer_flags[ 1 ],
+                         pointer_flags.size() - 1,
+                         const_cast<CXUnsavedFile *>( unsaved ),
+                         cxunsaved_files.size(),
+                         EditingOptions(),
+                         &clang_translation_unit_ );
+
+  if ( result != CXError_Success )
     boost_throw( ClangParseError() );
 
   // Only with a reparse is the preamble precompiled. This issue was fixed
@@ -179,7 +192,7 @@ std::vector< CompletionData > TranslationUnit::CandidatesForLocation(
                           column,
                           const_cast<CXUnsavedFile *>( unsaved ),
                           cxunsaved_files.size(),
-                          completionOptions() ),
+                          CompletionOptions() ),
     clang_disposeCodeCompleteResults );
 
   std::vector< CompletionData > candidates = ToCompletionDataVector(
@@ -337,7 +350,7 @@ std::string TranslationUnit::GetEnclosingFunctionAtLocation(
 void TranslationUnit::Reparse(
   std::vector< CXUnsavedFile > &unsaved_files ) {
   unsigned options = ( clang_translation_unit_
-                       ? reparseOptions( clang_translation_unit_ )
+                       ? ReparseOptions( clang_translation_unit_ )
                        : static_cast<unsigned>( CXReparse_None ) );
 
   Reparse( unsaved_files, options );

ycmd/completers/cpp/clang_helpers.py

@@ -18,10 +18,6 @@
 # along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
 
 
+# Provided for backwards compatibility with old ycm_extra_conf files.
 def PrepareClangFlags( flags, filename ):
-  # When flags come from the compile_commands.json file, the first flag is
-  # usually the path to the compiler that should be invoked. We want to strip
-  # that.
-  if flags and not flags[ 0 ].startswith( '-' ):
-    return flags[ 1: ]
   return flags

ycmd/completers/cpp/flags.py

@@ -229,7 +229,7 @@ def _CompilerToLanguageFlag( flags ):
   language = ( 'c++' if CPP_COMPILER_REGEX.search( flags[ 0 ] ) else
                'c' )
 
-  return [ '-x', language ] + flags[ 1: ]
+  return flags[ :1 ] + [ '-x', language ] + flags[ 1: ]
 
 
 def _RemoveUnusedFlags( flags, filename ):
@@ -242,6 +242,13 @@ def _RemoveUnusedFlags( flags, filename ):
 
   new_flags = []
 
+  # When flags come from the compile_commands.json file, the first flag is
+  # usually the path to the compiler that should be invoked. Directly move it to
+  # the new_flags list so it doesn't get stripped of in the loop below.
+  if not flags[ 0 ].startswith( '-' ):
+    new_flags = flags[ :1 ]
+    flags = flags[ 1: ]
+
   skip_next = False
   previous_flag_is_include = False
   previous_flag_starts_with_dash = False
@@ -300,6 +307,6 @@ def _ExtraClangFlags():
 def _SpecialClangIncludes():
   libclang_dir = os.path.dirname( ycm_core.__file__ )
   path_to_includes = os.path.join( libclang_dir, 'clang_includes' )
-  return [ '-isystem', path_to_includes ]
+  return [ '-resource-dir=' + path_to_includes ]
 
 

ycmd/completers/cpp/tests/flags_test.py

@@ -18,6 +18,7 @@
 # along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
 
 from nose.tools import eq_
+from nose.tools import ok_
 from .. import flags
 
 
@@ -111,45 +112,48 @@ def RemoveUnusedFlags_RemoveMP_test():
 
 
 def RemoveUnusedFlags_RemoveFilename_test():
-  expected = [ '-foo', '-bar' ]
+  expected = [ 'foo', '-bar' ]
   to_remove = [ 'file' ]
   filename = 'file'
 
   eq_( expected,
        flags._RemoveUnusedFlags( expected + to_remove, filename ) )
 
   eq_( expected,
-       flags._RemoveUnusedFlags( to_remove + expected, filename ) )
+        flags._RemoveUnusedFlags( expected[ :1 ] + to_remove + expected[ 1: ],
+                                  filename ) )
 
   eq_( expected,
        flags._RemoveUnusedFlags(
          expected[ :1 ] + to_remove + expected[ -1: ], filename ) )
 
 
 def RemoveUnusedFlags_RemoveFlagWithoutPrecedingDashFlag_test():
-  expected = [ '-foo', '-x', 'c++', '-bar', 'include_dir' ]
+  expected = [ 'g++', '-foo', '-x', 'c++', '-bar', 'include_dir' ]
   to_remove = [ 'unrelated_file' ]
   filename = 'file'
 
   eq_( expected,
        flags._RemoveUnusedFlags( expected + to_remove, filename ) )
 
   eq_( expected,
-       flags._RemoveUnusedFlags( to_remove + expected, filename ) )
+        flags._RemoveUnusedFlags( expected[ :1 ] + to_remove + expected[ 1: ],
+                                  filename ) )
 
 
 def RemoveUnusedFlags_RemoveFilenameWithoutPrecedingInclude_test():
   def tester( flag ):
-    expected = [ flag, '/foo/bar', '-isystem/zoo/goo' ]
+    expected = [ 'clang', flag, '/foo/bar', '-isystem/zoo/goo' ]
 
     eq_( expected,
          flags._RemoveUnusedFlags( expected + to_remove, filename ) )
 
     eq_( expected,
-         flags._RemoveUnusedFlags( to_remove + expected, filename ) )
+          flags._RemoveUnusedFlags( expected[ :1 ] + to_remove + expected[ 1: ],
+                                    filename ) )
 
-    eq_( expected + expected,
-         flags._RemoveUnusedFlags( expected + to_remove + expected,
+    eq_( expected + expected[ 1: ],
+          flags._RemoveUnusedFlags( expected + to_remove + expected[ 1: ],
                                    filename ) )
 
   include_flags = [ '-isystem', '-I', '-iquote', '--sysroot=', '-isysroot',
@@ -191,7 +195,7 @@ def _ReplaceCompilerTester( compiler, language ):
   expected = [ '-foo', '-bar' ]
 
   for to_remove in to_removes:
-    eq_( [ '-x', language ] + expected,
+    eq_( [ compiler, '-x', language ] + expected,
          flags._CompilerToLanguageFlag( to_remove + [ compiler ] + expected ) )
 
 
@@ -213,3 +217,13 @@ def CompilerToLanguageFlag_ReplaceCppCompiler_test():
 
   for compiler in compilers:
     yield _ReplaceCompilerTester, compiler, 'c++'
+
+def ExtraClangFlags_test():
+  flags_object = flags.Flags()
+  num_found = 0
+  for flag in flags_object.extra_clang_flags:
+    if flag.startswith( '-resource-dir=' ):
+      ok_( flag.endswith( 'clang_includes' ) )
+      num_found += 1
+
+  eq_( 1, num_found )