Tool to help with multiple LLVM working trees

llvmsc.py

#!/usr/bin/env python3
'''
This script helps in maintaining multiple working trees for the LLVM project.
'''

import os
import subprocess


def ensure_main_tree(main):
    if not os.path.exists(main):
        print('Main working tree does not exist, cloning it...')
        os.makedirs(main)
        subprocess.check_call([
            'git', 'clone',
            'https://github.com/llvm/llvm-project',
            '.'
        ], cwd=main)
        subprocess.check_call([
            'git', 'config',
            'extensions.worktreeConfig', 'true'
        ], cwd=main)


def get_git_path(tree):
    return subprocess.check_output([
        'git', 'rev-parse', '--git-path', tree
    ])


def list_cmd(args):
    '''Lists all working trees.'''
    ensure_main_tree(args.main)
    subprocess.check_call(['git', 'worktree', 'list'], cwd=args.main)


def add_cmd(args):
    '''Creates a new working directory and checks out desired projects.'''
    ensure_main_tree(args.main)

    # Add a new working tree, without any files
    subprocess.check_call([
        'git', 'worktree', 'add',
        '--no-checkout',
        '-b', args.branch,
        os.path.abspath(args.dir),
        args.base
    ], cwd=args.main)

    # Initialize sparse checkout, which checks out regular files in the root
    # directory, but does not include any subdirectories.
    subprocess.check_call(['git', 'sparse-checkout', 'init'], cwd=args.dir)

    # Add any subprojects requested
    subprocess.check_call([
        'git', 'sparse-checkout', 'add',
        'llvm', *args.projects
    ], cwd=args.dir)

    if args.cmake:
        # Create the build directory
        build_dir = os.path.join(args.dir, 'build')
        os.mkdir(build_dir)

        # Run CMake
        subprocess.check_call([
            'cmake',
            '-G', args.cmake_generator,
            '-DCMAKE_BUILD_TYPE=' + args.cmake_build_type,
            '-DLLVM_ENABLE_PROJECTS=' + ';'.join(args.projects),
            '-DLLVM_TARGETS_TO_BUILD=' + ';'.join(args.targets),
            '../llvm'
        ], cwd=build_dir)


if __name__ == '__main__':
    import argparse

    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        '--main',
        default=os.path.expanduser('~/SourceCache/llvm-project'),
        help='path to main working tree'
    )

    subparsers = parser.add_subparsers(dest='command', required=True)

    # List subcommand options
    parser_list = subparsers.add_parser('list', description=list_cmd.__doc__)
    parser_list.set_defaults(func=list_cmd)

    # Add subcommand options
    parser_add = subparsers.add_parser('add', description=add_cmd.__doc__)
    parser_add.set_defaults(func=add_cmd)
    parser_add.add_argument(
        '--project', '-p',
        metavar='PROJECT', dest='projects', action='append', default=[],
        help='include a project in the checkout (e.g., clang)'
    )
    parser_add.add_argument(
        '--target', '-t',
        metavar='TARGET', dest='targets', action='append',
        help='enable a LLVM target (if none supplied, x86 is default)'
    )
    parser_add.add_argument(
        '--no-cmake',
        dest='cmake', action='store_false',
        help='do not run CMake in the new working tree'
    )
    parser_add.add_argument(
        '--cmake-generator', default='Ninja',
        help='CMake generator (see `man cmake`)'
    )
    parser_add.add_argument(
        '--cmake-build-type', default='RelWithDebInfo',
        help='CMake build type (see `man cmake`)'
    )
    parser_add.add_argument(
        'dir',
        help='destination directory to create'
    )
    parser_add.add_argument(
        'branch',
        help='name of the new branch to create for this work tree'
    )
    parser_add.add_argument(
        'base',
        nargs='?', default='master',
        help='base commit or branch to check out (default: master)'
    )

    args = parser.parse_args()

    # Fixups
    if args.command == 'add':
        if not args.targets:
            args.targets = ['X86']

    args.func(args)