Add system header directories to user flags

.gitignore

@@ -13,6 +13,9 @@
 *.la
 *.a
 
+# Executables
+ycm_fake_clang*
+
 # Clang archives
 clang_archives
 

CORE_VERSION

@@ -1 +1 @@
-39
+40

build.py

@@ -530,22 +530,12 @@ def BuildYcmdLib( cmake, cmake_common_args, script_args ):
                quiet = script_args.quiet,
                status_message = 'Generating ycmd build configuration' )
 
-    build_targets = [ 'ycm_core' ]
-    if script_args.core_tests:
-      build_targets.append( 'ycm_core_tests' )
-    if 'YCM_BENCHMARK' in os.environ:
-      build_targets.append( 'ycm_core_benchmarks' )
-
     build_config = GetCMakeBuildConfiguration( script_args )
-
-    for target in build_targets:
-      build_command = ( [ cmake, '--build', '.', '--target', target ] +
-                        build_config )
-      CheckCall( build_command,
-                 exit_message = BUILD_ERROR_MESSAGE,
-                 quiet = script_args.quiet,
-                 status_message = 'Compiling ycmd target: {0}'.format(
-                   target ) )
+    build_command = [ cmake, '--build', '.' ] + build_config
+    CheckCall( build_command,
+               exit_message = BUILD_ERROR_MESSAGE,
+               quiet = script_args.quiet,
+               status_message = 'Compiling ycmd' )
 
     if script_args.core_tests:
       RunYcmdTests( script_args, build_dir )

cpp/ycm/CMakeLists.txt

@@ -204,11 +204,10 @@ set( PYBIND11_INCLUDES_DIR "${CMAKE_SOURCE_DIR}/pybind11" )
 
 file( GLOB_RECURSE SERVER_SOURCES *.h *.cpp )
 
-# The test and benchmark sources are a part of a different target, so we remove
-# them. The CMakeFiles cpp file is picked up when the user creates an in-source
-# build, and we don't want that. We also remove client-specific code.
-file( GLOB_RECURSE to_remove tests/*.h tests/*.cpp benchmarks/*.h
-                             benchmarks/*.cpp CMakeFiles/*.cpp *client* )
+# The tests, benchmarks, and fake_clang sources are a part of a different
+# target, so we remove them. The CMakeFiles cpp file is picked up when the user
+# creates an in-source build, and we don't want that.
+file( GLOB_RECURSE to_remove tests/* benchmarks/* fake_clang/* CMakeFiles/* )
 
 if( to_remove )
   list( REMOVE_ITEM SERVER_SOURCES ${to_remove} )
@@ -460,6 +459,9 @@ if( SYSTEM_IS_OPENBSD OR SYSTEM_IS_FREEBSD )
   set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pthread" )
 endif()
 
+if ( USE_CLANG_COMPLETER )
+  add_subdirectory( fake_clang )
+endif()
 if ( DEFINED ENV{YCM_TESTRUN} )
   add_subdirectory( tests )
 endif()

cpp/ycm/fake_clang/CMakeLists.txt

@@ -0,0 +1,38 @@
+# Copyright (C) 2018 ycmd contributors
+#
+# This file is part of ycmd.
+#
+# ycmd is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# ycmd is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with ycmd.  If not, see <http://www.gnu.org/licenses/>.
+
+project( ycm_fake_clang )
+cmake_minimum_required( VERSION 2.8 )
+
+include_directories( ${ycm_core_SOURCE_DIR} )
+
+add_executable( ${PROJECT_NAME} main.cpp )
+
+target_link_libraries( ${PROJECT_NAME}
+                       ${LIBCLANG_TARGET} )
+
+# Build ycm_fake_clang in ycmd root folder.
+if ( MSVC )
+  foreach( OUTPUTCONFIG ${CMAKE_CONFIGURATION_TYPES} )
+    string( TOUPPER ${OUTPUTCONFIG} OUTPUTCONFIG )
+    set_target_properties( ${PROJECT_NAME} PROPERTIES
+      RUNTIME_OUTPUT_DIRECTORY_${OUTPUTCONFIG} ${PROJECT_SOURCE_DIR}/../../.. )
+  endforeach()
+else()
+  set_target_properties( ${PROJECT_NAME} PROPERTIES
+    RUNTIME_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR}/../../.. )
+endif()

cpp/ycm/fake_clang/main.cpp

@@ -0,0 +1,42 @@
+// Copyright (C) 2018 ycmd contributors
+//
+// This file is part of ycmd.
+//
+// ycmd is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ycmd is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ycmd.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <clang-c/Index.h>
+#include <iostream>
+
+// This small program simulates the output of the clang executable when ran with
+// the -E and -v flags. It takes a list of flags as arguments and creates the
+// corresponding translation unit. When retrieving user flags, ycmd executes
+// this program as follows
+//
+//   ycm_fake_clang -resource-dir=... [flag ...] -E -v filename
+//
+// and extract the list of system header paths from the output. These
+// directories are then added to the list of flags to provide completion of
+// system headers in include statements and allow jumping to these headers.
+int main( int argc, char **argv ) {
+  CXIndex index = clang_createIndex( 0, 0 );
+  CXTranslationUnit tu;
+  CXErrorCode result = clang_parseTranslationUnit2FullArgv(
+    index, nullptr, argv, argc, nullptr, 0, CXTranslationUnit_None, &tu );
+  if ( result != CXError_Success ) {
+    return EXIT_FAILURE;
+  }
+
+  clang_disposeTranslationUnit( tu );
+  return EXIT_SUCCESS;
+}