src/build/arc.ycm_extra_conf.py - arc/arc - Git at Google

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

 """Autocompletion config for YouCompleteMe in ARC.

 USAGE:

   1. Install YCM [https://github.com/Valloric/YouCompleteMe]
          (Googlers should check out [go/ycm])

   2. Point to this config file in your .vimrc:
          let g:ycm_global_ycm_extra_conf =
              '<arc_depot>/src/build/arc.ycm_extra_conf.py'

   3. Profit!


 Usage notes:

   * You must have built ARC before using this.

   * Not all files have correct completion information since ninja does not use
     gomacc for all C++ files.

   * You can avoid the call to ninja every time a file is saved/loaded by
     creating a JSON compilation database with the following command:
       $ ninja -t compdb cxx.nacl_i686 cc.nacl_i686 > \
         ycm/compile_commands.json
     Replacing 'nacl_i686' with the current ARC target.

 Hacking notes:

   * The purpose of this script is to construct an accurate enough command line
     for YCM to pass to clang so it can build and extract the symbols.

   * Right now, we only pull some flags. That seems to be sufficient for
     everything I have used it for.

   * That whole ninja & clang thing? We could support other configs if someone
     were willing to write the correct commands and a parser.

   * This has only been tested on gPrecise.
 """

 import os
 import subprocess


 # Flags from YCM's default config.
 default_flags = [
     '-DUSE_CLANG_COMPLETER',
     '-x',
     'c++',
 ]


 def _get_arc_root():
   """Searches for the root of the ARC checkout.

   This file is checked in the src/build/ directory, so we only need to go
   up two directories.

   Returns:
     (String) Path of the ARC root.
   """
   return os.path.abspath(
       os.path.join(os.path.dirname(os.path.realpath(__file__)), '..', '..'))


 def _get_source_filename(filename):
   """Gets the corresponding source file for headers.

   Header files do not have an associated gomacc command. Instead, try to
   find its corresponding .cc/.cpp file to get the right flags.

   Args:
     filename: (String) Path to the file being edited.

   Returns:
     (String) Best guess for the source file corresponding to |filename|.
   """
   root, ext = os.path.splitext(filename)
   if ext == '.h':
     alternates = ['.cc', '.cpp']
     for alt_extension in alternates:
       alt_name = root + alt_extension
       if os.path.exists(alt_name):
         return alt_name
   return filename


 def _get_staging_relative_filename(arc_root, filename):
   if not (arc_root and filename.startswith(arc_root)):
     return filename

   # For ARC, ninja and the compilation database it writes out both use file
   # paths relative to the staging directory.
   rel_filename = filename[len(arc_root) + 1:]

   if rel_filename.startswith('mods/'):
     rel_filename = 'out/staging/' + rel_filename[len('mods/'):]
   elif rel_filename.startswith('third_party/'):
     rel_filename = 'out/staging/' + rel_filename[len('third_party/'):]
   elif rel_filename.startswith('src/'):
     rel_filename = 'out/staging/' + rel_filename

   return os.path.join(arc_root, rel_filename)


 def _get_clang_command_compdb(arc_root, compilation_database_folder,
                               filename):
   """Query the compdb to get the compiler flags for |filename|.

   This avoids calling ninja every time YCM needs to get the compiler
   flags. The compilation database must be regenerated every time a file
   is added, or ./configure is called. See here for more details:
   http://clang.llvm.org/docs/JSONCompilationDatabase.html

   Args:
     compilation_database_folder: (String) The path of the JSON compilation
       database: the ycm/ directory.
     arc_root: (String) Path to the root of the ARC repository.
     filename: (String) Path to source file being edited.

   Returns:
     (List of Strings) Command line arguments for clang.
   """
   import ycm_core
   filename = _get_staging_relative_filename(arc_root, filename)
   database = ycm_core.CompilationDatabase(compilation_database_folder)
   compilation_info = database.GetCompilationInfoForFile(filename)

   if not compilation_info:
     return []

   return compilation_info.compiler_flags_


 def _get_compiled_output_file_from_ninja(arc_root, filename):
   stdout = subprocess.check_output(
       ['ninja', '-v', '-C', arc_root, '-t', 'query', filename])

   object_filename = os.path.splitext(os.path.basename(filename))[0] + '.o'
   for line in stdout.split('\n'):
     if line.endswith(object_filename):
       return line.strip()
   return None


 def _get_build_commands_from_ninja(arc_root, filename):
   stdout = subprocess.check_output(
       ['ninja', '-v', '-C', arc_root, '-t', 'commands', filename])
   return stdout.split('\n')


 def _find_last_gomacc_command(commands):
   for line in reversed(commands):
     if 'gomacc' in line:
       return line.split(' ')
   return None


 def _get_clang_command_ninja(arc_root, filename):
   """Returns the command line to build |filename|.

   Asks ninja how it would build the source file. If the specified file is a
   header, tries to find its companion source file first.

   Args:
     arc_root: (String) Path to the root of the ARC repository.
     filename: (String) Path to source file being edited.

   Returns:
     (List of Strings) Command line arguments for clang.
   """
   if not arc_root:
     return []

   # Ask ninja about the dependency graph for the source file
   filename = _get_staging_relative_filename(arc_root, filename)
   rel_filename = filename[len(arc_root) + 1:]
   output_filename = _get_compiled_output_file_from_ninja(arc_root,
                                                          rel_filename)
   if not output_filename:
     return []

   commands = _get_build_commands_from_ninja(arc_root, output_filename)
   if not commands:
     return []

   # Ninja might execute several commands to build something. We want the last
   # gomacc command.
   gomacc = _find_last_gomacc_command(commands)
   if not gomacc:
     return []
   return gomacc


 def absolute_path(filepath, arc_root):
   if filepath[0] == '/':
     return filepath
   return os.path.normpath(os.path.join(arc_root, filepath))


 def _process_flags(arc_root, flags):
   """Filter out flags and convert all paths to absolute paths.

   Args:
     arc_root: (String) Path to the root of the ARC repository.
     flags: (List of Strings) List of flags returned by ninja/compdb

   Returns:
     (List of Strings) The filtered flags ready for YCM"""
   arc_flags = []

   take_next_as_path = False

   # Parse out whitelisted flags. These seem to be the only ones that are
   # important for YCM's purposes.
   for flag in flags:
     if take_next_as_path:
       take_next_as_path = False
       arc_flags.append(absolute_path(flag, arc_root))
     elif flag.startswith('-I'):
       # Relative paths need to be resolved, because they're relative to the
       # output dir, not the source.
       if flag == '-I':
         arc_flags.append('-I')
         take_next_as_path = True
       else:
         arc_flags.append('-I' + absolute_path(flag[2:], arc_root))
     elif flag.startswith('-') and flag[1] in 'DUWFfmO':
       if flag == '-Wno-deprecated-register' or flag == '-Wno-header-guard':
         # These flags causes libclang (3.3) to crash. Remove it until things
         # are fixed.
         continue
       arc_flags.append(flag)

   return arc_flags


 def FlagsForFile(filename):
   """This is the main entry point for YCM. Its interface is fixed.

   Args:
     filename: (String) Path to source file being edited.

   Returns:
     (Dictionary)
       'flags': (List of Strings) Command line flags.
       'do_cache': (Boolean) True if the result should be cached.
   """
   arc_root = _get_arc_root()
   compilation_database_folder = os.path.join(arc_root, 'ycm')
   filename = _get_source_filename(filename)
   arc_flags = []
   # Try reading the compilation database first
   if os.path.exists(compilation_database_folder):
     arc_flags = _get_clang_command_compdb(arc_root,
                                           compilation_database_folder,
                                           filename)
   # Fall back to getting it from ninja
   if not arc_flags:
     arc_flags = _get_clang_command_ninja(arc_root,
                                          filename)
   final_flags = default_flags + _process_flags(arc_root, arc_flags)
   return {
       'flags': final_flags,
       'do_cache': True
   }
	# Copyright (c) 2013 The Chromium Authors. All rights reserved.
	# Use of this source code is governed by a BSD-style license that can be
	# found in the LICENSE file.

	"""Autocompletion config for YouCompleteMe in ARC.

	USAGE:

	1. Install YCM [https://github.com/Valloric/YouCompleteMe]
	(Googlers should check out [go/ycm])

	2. Point to this config file in your .vimrc:
	let g:ycm_global_ycm_extra_conf =
	'<arc_depot>/src/build/arc.ycm_extra_conf.py'

	3. Profit!


	Usage notes:

	* You must have built ARC before using this.

	* Not all files have correct completion information since ninja does not use
	gomacc for all C++ files.

	* You can avoid the call to ninja every time a file is saved/loaded by
	creating a JSON compilation database with the following command:
	$ ninja -t compdb cxx.nacl_i686 cc.nacl_i686 > \
	ycm/compile_commands.json
	Replacing 'nacl_i686' with the current ARC target.

	Hacking notes:

	* The purpose of this script is to construct an accurate enough command line
	for YCM to pass to clang so it can build and extract the symbols.

	* Right now, we only pull some flags. That seems to be sufficient for
	everything I have used it for.

	* That whole ninja & clang thing? We could support other configs if someone
	were willing to write the correct commands and a parser.

	* This has only been tested on gPrecise.
	"""

	import os
	import subprocess


	# Flags from YCM's default config.
	default_flags = [
	'-DUSE_CLANG_COMPLETER',
	'-x',
	'c++',
	]


	def _get_arc_root():
	"""Searches for the root of the ARC checkout.

	This file is checked in the src/build/ directory, so we only need to go
	up two directories.

	Returns:
	(String) Path of the ARC root.
	"""
	return os.path.abspath(
	os.path.join(os.path.dirname(os.path.realpath(__file__)), '..', '..'))


	def _get_source_filename(filename):
	"""Gets the corresponding source file for headers.

	Header files do not have an associated gomacc command. Instead, try to
	find its corresponding .cc/.cpp file to get the right flags.

	Args:
	filename: (String) Path to the file being edited.

	Returns:
	(String) Best guess for the source file corresponding to \|filename\|.
	"""
	root, ext = os.path.splitext(filename)
	if ext == '.h':
	alternates = ['.cc', '.cpp']
	for alt_extension in alternates:
	alt_name = root + alt_extension
	if os.path.exists(alt_name):
	return alt_name
	return filename


	def _get_staging_relative_filename(arc_root, filename):
	if not (arc_root and filename.startswith(arc_root)):
	return filename

	# For ARC, ninja and the compilation database it writes out both use file
	# paths relative to the staging directory.
	rel_filename = filename[len(arc_root) + 1:]

	if rel_filename.startswith('mods/'):
	rel_filename = 'out/staging/' + rel_filename[len('mods/'):]
	elif rel_filename.startswith('third_party/'):
	rel_filename = 'out/staging/' + rel_filename[len('third_party/'):]
	elif rel_filename.startswith('src/'):
	rel_filename = 'out/staging/' + rel_filename

	return os.path.join(arc_root, rel_filename)


	def _get_clang_command_compdb(arc_root, compilation_database_folder,
	filename):
	"""Query the compdb to get the compiler flags for \|filename\|.

	This avoids calling ninja every time YCM needs to get the compiler
	flags. The compilation database must be regenerated every time a file
	is added, or ./configure is called. See here for more details:
	http://clang.llvm.org/docs/JSONCompilationDatabase.html

	Args:
	compilation_database_folder: (String) The path of the JSON compilation
	database: the ycm/ directory.
	arc_root: (String) Path to the root of the ARC repository.
	filename: (String) Path to source file being edited.

	Returns:
	(List of Strings) Command line arguments for clang.
	"""
	import ycm_core
	filename = _get_staging_relative_filename(arc_root, filename)
	database = ycm_core.CompilationDatabase(compilation_database_folder)
	compilation_info = database.GetCompilationInfoForFile(filename)

	if not compilation_info:
	return []

	return compilation_info.compiler_flags_


	def _get_compiled_output_file_from_ninja(arc_root, filename):
	stdout = subprocess.check_output(
	['ninja', '-v', '-C', arc_root, '-t', 'query', filename])

	object_filename = os.path.splitext(os.path.basename(filename))[0] + '.o'
	for line in stdout.split('\n'):
	if line.endswith(object_filename):
	return line.strip()
	return None


	def _get_build_commands_from_ninja(arc_root, filename):
	stdout = subprocess.check_output(
	['ninja', '-v', '-C', arc_root, '-t', 'commands', filename])
	return stdout.split('\n')


	def _find_last_gomacc_command(commands):
	for line in reversed(commands):
	if 'gomacc' in line:
	return line.split(' ')
	return None


	def _get_clang_command_ninja(arc_root, filename):
	"""Returns the command line to build \|filename\|.

	Asks ninja how it would build the source file. If the specified file is a
	header, tries to find its companion source file first.

	Args:
	arc_root: (String) Path to the root of the ARC repository.
	filename: (String) Path to source file being edited.

	Returns:
	(List of Strings) Command line arguments for clang.
	"""
	if not arc_root:
	return []

	# Ask ninja about the dependency graph for the source file
	filename = _get_staging_relative_filename(arc_root, filename)
	rel_filename = filename[len(arc_root) + 1:]
	output_filename = _get_compiled_output_file_from_ninja(arc_root,
	rel_filename)
	if not output_filename:
	return []

	commands = _get_build_commands_from_ninja(arc_root, output_filename)
	if not commands:
	return []

	# Ninja might execute several commands to build something. We want the last
	# gomacc command.
	gomacc = _find_last_gomacc_command(commands)
	if not gomacc:
	return []
	return gomacc


	def absolute_path(filepath, arc_root):
	if filepath[0] == '/':
	return filepath
	return os.path.normpath(os.path.join(arc_root, filepath))


	def _process_flags(arc_root, flags):
	"""Filter out flags and convert all paths to absolute paths.

	Args:
	arc_root: (String) Path to the root of the ARC repository.
	flags: (List of Strings) List of flags returned by ninja/compdb

	Returns:
	(List of Strings) The filtered flags ready for YCM"""
	arc_flags = []

	take_next_as_path = False

	# Parse out whitelisted flags. These seem to be the only ones that are
	# important for YCM's purposes.
	for flag in flags:
	if take_next_as_path:
	take_next_as_path = False
	arc_flags.append(absolute_path(flag, arc_root))
	elif flag.startswith('-I'):
	# Relative paths need to be resolved, because they're relative to the
	# output dir, not the source.
	if flag == '-I':
	arc_flags.append('-I')
	take_next_as_path = True
	else:
	arc_flags.append('-I' + absolute_path(flag[2:], arc_root))
	elif flag.startswith('-') and flag[1] in 'DUWFfmO':
	if flag == '-Wno-deprecated-register' or flag == '-Wno-header-guard':
	# These flags causes libclang (3.3) to crash. Remove it until things
	# are fixed.
	continue
	arc_flags.append(flag)

	return arc_flags


	def FlagsForFile(filename):
	"""This is the main entry point for YCM. Its interface is fixed.

	Args:
	filename: (String) Path to source file being edited.

	Returns:
	(Dictionary)
	'flags': (List of Strings) Command line flags.
	'do_cache': (Boolean) True if the result should be cached.
	"""
	arc_root = _get_arc_root()
	compilation_database_folder = os.path.join(arc_root, 'ycm')
	filename = _get_source_filename(filename)
	arc_flags = []
	# Try reading the compilation database first
	if os.path.exists(compilation_database_folder):
	arc_flags = _get_clang_command_compdb(arc_root,
	compilation_database_folder,
	filename)
	# Fall back to getting it from ninja
	if not arc_flags:
	arc_flags = _get_clang_command_ninja(arc_root,
	filename)
	final_flags = default_flags + _process_flags(arc_root, arc_flags)
	return {
	'flags': final_flags,
	'do_cache': True
	}