gecko-dev/build/moz.configure/toolchain.configure

# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
# vim: set filetype=python:
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

imply_option('--enable-release', mozilla_official)
imply_option('--enable-release', depends_if('MOZ_AUTOMATION')(lambda x: True))

js_option('--enable-release',
          default=milestone.is_release_or_beta,
          help='{Build|Do not build} with more conservative, release '
               'engineering-oriented options.{ This may slow down builds.|}')


@depends('--enable-release')
def developer_options(value):
    if not value:
        return True


add_old_configure_assignment('DEVELOPER_OPTIONS', developer_options)
set_config('DEVELOPER_OPTIONS', developer_options)

# Code optimization
# ==============================================================

js_option('--disable-optimize',
          nargs='?',
          help='Disable optimizations via compiler flags')


@depends('--enable-optimize', '--help')
def moz_optimize(option, _):
    flags = None

    if len(option):
        val = '2'
        flags = option[0]
    elif option:
        val = '1'
    else:
        val = None

    return namespace(
        optimize=val,
        flags=flags,
    )


set_config('MOZ_OPTIMIZE', moz_optimize.optimize)
add_old_configure_assignment('MOZ_OPTIMIZE', moz_optimize.optimize)
add_old_configure_assignment('MOZ_CONFIGURE_OPTIMIZE_FLAGS', moz_optimize.flags)

# yasm detection
# ==============================================================
yasm = check_prog('YASM', ['yasm'], allow_missing=True)


@depends_if(yasm)
@checking('yasm version')
def yasm_version(yasm):
    version = check_cmd_output(
        yasm, '--version',
        onerror=lambda: die('Failed to get yasm version.')
    ).splitlines()[0].split()[1]
    return Version(version)


@depends(yasm, target)
def yasm_asflags(yasm, target):
    if yasm:
        asflags = {
            ('OSX', 'x86'): ['-f', 'macho32'],
            ('OSX', 'x86_64'): ['-f', 'macho64'],
            ('WINNT', 'x86'): ['-f', 'win32'],
            ('WINNT', 'x86_64'): ['-f', 'x64'],
        }.get((target.os, target.cpu), None)
        if asflags is None:
            # We're assuming every x86 platform we support that's
            # not Windows or Mac is ELF.
            if target.cpu == 'x86':
                asflags = ['-f', 'elf32']
            elif target.cpu == 'x86_64':
                asflags = ['-f', 'elf64']
        if asflags:
            asflags += ['-rnasm', '-pnasm']
        return asflags


set_config('YASM_ASFLAGS', yasm_asflags)


# Android NDK
# ==============================================================


@depends('--disable-compile-environment', target)
def compiling_android(compile_env, target):
    return compile_env and target.os == 'Android'


include('android-ndk.configure', when=compiling_android)

with only_when(target_is_osx):
    # MacOS deployment target version
    # ==============================================================
    # This needs to happen before any compilation test is done.

    option('--enable-macos-target', env='MACOSX_DEPLOYMENT_TARGET', nargs=1,
           default='10.9', help='Set the minimum MacOS version needed at runtime')


    @depends('--enable-macos-target')
    @imports(_from='os', _import='environ')
    def macos_target(value):
        if value:
            # Ensure every compiler process we spawn uses this value.
            environ['MACOSX_DEPLOYMENT_TARGET'] = value[0]
            return value[0]


    set_config('MACOSX_DEPLOYMENT_TARGET', macos_target)
    add_old_configure_assignment('MACOSX_DEPLOYMENT_TARGET', macos_target)


@depends(host)
def host_is_osx(host):
    if host.os == 'OSX':
        return True


with only_when(host_is_osx | target_is_osx):
    # MacOS SDK
    # =========
    js_option('--with-macos-sdk', env='MACOS_SDK_DIR', nargs=1,
           help='Location of platform SDK to use')

    @depends('--with-macos-sdk', host)
    @imports(_from='os.path', _import='isdir')
    @imports(_from='biplist', _import='readPlist')
    def macos_sdk(sdk, host):
        sdk_min_version = Version('10.11')
        sdk_max_version = Version('11.0')

        if sdk:
            sdk = sdk[0]
        elif host.os == 'OSX':
            sdk = check_cmd_output('xcrun', '--show-sdk-path', onerror=lambda: '').rstrip()
            if not sdk:
                die('Could not find the macOS SDK. Please use --with-macos-sdk to give '
                    'the path to a macOS SDK.')
        else:
            die('Need a macOS SDK when targeting macOS. Please use --with-macos-sdk '
                'to give the path to a macOS SDK.')

        if not isdir(sdk):
            die('SDK not found in %s. When using --with-macos-sdk, you must specify a '
                'valid SDK. SDKs are installed when the optional cross-development '
                'tools are selected during the Xcode/Developer Tools installation.'
                % sdk)
        obj = readPlist(os.path.join(sdk, 'SDKSettings.plist'))
        if not obj:
            die('Error parsing SDKSettings.plist in the SDK directory: %s' % sdk)
        if 'Version' not in obj:
            die('Error finding Version information in SDKSettings.plist from the SDK: %s' % sdk)
        version = Version(obj['Version'])
        if version < sdk_min_version:
            die('SDK version "%s" is too old. Please upgrade to at least %s. '
                'You may need to point to it using --with-macos-sdk=<path> in your '
                'mozconfig.' % (version, sdk_min_version))
        if version > sdk_max_version:
            die('SDK version "%s" is unsupported. Please downgrade to version '
                '%s. You may need to point to it using --with-macos-sdk=<path> in '
                'your mozconfig.' % (version, sdk_max_version))
        return sdk

    set_config('MACOS_SDK_DIR', macos_sdk)


with only_when(target_is_osx):
    with only_when(cross_compiling):
        option('--with-macos-private-frameworks',
               env="MACOS_PRIVATE_FRAMEWORKS_DIR", nargs=1,
               help='Location of private frameworks to use')

        @depends_if('--with-macos-private-frameworks')
        @imports(_from='os.path', _import='isdir')
        def macos_private_frameworks(value):
            if value and not isdir(value[0]):
                die('PrivateFrameworks not found not found in %s. When using '
                    '--with-macos-private-frameworks, you must specify a valid '
                    'directory', value[0])
            return value[0]

    @depends(macos_private_frameworks)
    def macos_private_frameworks(value):
        if value:
            return value
        return '/System/Library/PrivateFrameworks'

    set_config('MACOS_PRIVATE_FRAMEWORKS_DIR', macos_private_frameworks)


# Compiler wrappers
# ==============================================================
# Normally, we'd use js_option and automatically have those variables
# propagated to js/src, but things are complicated by possible additional
# wrappers in CC/CXX, and by other subconfigures that do not handle those
# options and do need CC/CXX altered.
option('--with-compiler-wrapper', env='COMPILER_WRAPPER', nargs=1,
       help='Enable compiling with wrappers such as distcc and ccache')

js_option('--with-ccache', env='CCACHE', nargs='?',
          help='Enable compiling with ccache')


@depends_if('--with-ccache')
def ccache(value):
    if len(value):
        return value
    # If --with-ccache was given without an explicit value, we default to
    # 'ccache'.
    return 'ccache'


ccache = check_prog('CCACHE', progs=(), input=ccache)

js_option(env='CCACHE_PREFIX',
          nargs=1,
          help='Compiler prefix to use when using ccache')

ccache_prefix = depends_if('CCACHE_PREFIX')(lambda prefix: prefix[0])
set_config('CCACHE_PREFIX', ccache_prefix)

# Distinguish ccache from sccache.


@depends_if(ccache)
def ccache_is_sccache(ccache):
    return check_cmd_output(ccache, '--version').startswith('sccache')


@depends(ccache, ccache_is_sccache)
def using_ccache(ccache, ccache_is_sccache):
    return ccache and not ccache_is_sccache


@depends_if(ccache, ccache_is_sccache)
def using_sccache(ccache, ccache_is_sccache):
    return ccache and ccache_is_sccache

js_option(env='RUSTC_WRAPPER', nargs=1,
          help='Wrap rust compilation with given tool')

@depends(ccache, ccache_is_sccache, 'RUSTC_WRAPPER')
@imports(_from='textwrap', _import='dedent')
@imports('os')
def check_sccache_version(ccache, ccache_is_sccache, rustc_wrapper):
    sccache_min_version = Version('0.2.13')

    def check_version(path):
        out = check_cmd_output(path, '--version')
        version = Version(out.rstrip().split()[-1])
        if version < sccache_min_version:
            die(dedent('''\
            sccache %s or later is required. sccache in use at %s has
            version %s.

            Please upgrade or acquire a new version with |./mach bootstrap|.
            '''), sccache_min_version, path, version)

    if ccache and ccache_is_sccache:
        check_version(ccache)

    if (rustc_wrapper and
        (os.path.splitext(os.path.basename(rustc_wrapper[0]))[0].lower() ==
         'sccache')):
        check_version(rustc_wrapper[0])

set_config('MOZ_USING_CCACHE', using_ccache)
set_config('MOZ_USING_SCCACHE', using_sccache)

option(env='SCCACHE_VERBOSE_STATS',
       help='Print verbose sccache stats after build')


@depends(using_sccache, 'SCCACHE_VERBOSE_STATS')
def sccache_verbose_stats(using_sccache, verbose_stats):
    return using_sccache and bool(verbose_stats)


set_config('SCCACHE_VERBOSE_STATS', sccache_verbose_stats)


@depends('--with-compiler-wrapper', ccache)
@imports(_from='mozbuild.shellutil', _import='split', _as='shell_split')
def compiler_wrapper(wrapper, ccache):
    if wrapper:
        raw_wrapper = wrapper[0]
        wrapper = shell_split(raw_wrapper)
        wrapper_program = find_program(wrapper[0])
        if not wrapper_program:
            die('Cannot find `%s` from the given compiler wrapper `%s`',
                wrapper[0], raw_wrapper)
        wrapper[0] = wrapper_program

    if ccache:
        if wrapper:
            return tuple([ccache] + wrapper)
        else:
            return (ccache,)
    elif wrapper:
        return tuple(wrapper)


@depends_if(compiler_wrapper)
def using_compiler_wrapper(compiler_wrapper):
    return True


set_config('MOZ_USING_COMPILER_WRAPPER', using_compiler_wrapper)


# GC rooting and hazard analysis.
# ==============================================================
option(env='MOZ_HAZARD', help='Build for the GC rooting hazard analysis')


@depends('MOZ_HAZARD')
def hazard_analysis(value):
    if value:
        return True


set_config('MOZ_HAZARD', hazard_analysis)


# Cross-compilation related things.
# ==============================================================
js_option('--with-toolchain-prefix', env='TOOLCHAIN_PREFIX', nargs=1,
          help='Prefix for the target toolchain')


@depends('--with-toolchain-prefix', target, cross_compiling)
def toolchain_prefix(value, target, cross_compiling):
    if value:
        return tuple(value)
    if cross_compiling:
        return ('%s-' % target.toolchain, '%s-' % target.alias)


@depends(toolchain_prefix, target)
def first_toolchain_prefix(toolchain_prefix, target):
    # Pass TOOLCHAIN_PREFIX down to the build system if it was given from the
    # command line/environment (in which case there's only one value in the tuple),
    # or when cross-compiling for Android or OSX.
    if toolchain_prefix and (target.os in ('Android', 'OSX') or len(toolchain_prefix) == 1):
        return toolchain_prefix[0]


set_config('TOOLCHAIN_PREFIX', first_toolchain_prefix)
add_old_configure_assignment('TOOLCHAIN_PREFIX', first_toolchain_prefix)


# Compilers
# ==============================================================
include('compilers-util.configure')


def try_preprocess(compiler, language, source, onerror=None):
    return try_invoke_compiler(compiler, language, source, ['-E'], onerror)


@imports(_from='mozbuild.configure.constants', _import='CompilerType')
@imports(_from='mozbuild.configure.constants',
         _import='CPU_preprocessor_checks')
@imports(_from='mozbuild.configure.constants',
         _import='kernel_preprocessor_checks')
@imports(_from='mozbuild.configure.constants',
         _import='OS_preprocessor_checks')
@imports(_from='six', _import='iteritems')
@imports(_from='textwrap', _import='dedent')
@imports(_from='__builtin__', _import='Exception')
def get_compiler_info(compiler, language):
    '''Returns information about the given `compiler` (command line in the
    form of a list or tuple), in the given `language`.

    The returned information includes:
    - the compiler type (clang-cl, clang or gcc)
    - the compiler version
    - the compiler supported language
    - the compiler supported language version
    '''
    # Note: We'd normally do a version check for clang, but versions of clang
    # in Xcode have a completely different versioning scheme despite exposing
    # the version with the same defines.
    # So instead, we make things such that the version is missing when the
    # clang used is below the minimum supported version (currently clang 5.0).
    # We then only include the version information when the compiler matches
    # the feature check, so that an unsupported version of clang would have
    # no version number.
    check = dedent('''\
        #if defined(_MSC_VER) && defined(__clang__) && defined(_MT)
        %COMPILER "clang-cl"
        %VERSION __clang_major__.__clang_minor__.__clang_patchlevel__
        #elif defined(__clang__)
        %COMPILER "clang"
        #  if __has_warning("-Wunguarded-availability")
        %VERSION __clang_major__.__clang_minor__.__clang_patchlevel__
        #  endif
        #elif defined(__GNUC__) && !defined(__MINGW32__)
        %COMPILER "gcc"
        %VERSION __GNUC__.__GNUC_MINOR__.__GNUC_PATCHLEVEL__
        #endif

        #if __cplusplus
        %cplusplus __cplusplus
        #elif __STDC_VERSION__
        %STDC_VERSION __STDC_VERSION__
        #endif
    ''')

    # While we're doing some preprocessing, we might as well do some more
    # preprocessor-based tests at the same time, to check the toolchain
    # matches what we want.
    for name, preprocessor_checks in (
        ('CPU', CPU_preprocessor_checks),
        ('KERNEL', kernel_preprocessor_checks),
        ('OS', OS_preprocessor_checks),
    ):
        for n, (value, condition) in enumerate(iteritems(preprocessor_checks)):
            check += dedent('''\
                #%(if)s %(condition)s
                %%%(name)s "%(value)s"
            ''' % {
                'if': 'elif' if n else 'if',
                'condition': condition,
                'name': name,
                'value': value,
            })
        check += '#endif\n'

    # Also check for endianness. The advantage of living in modern times is
    # that all the modern compilers we support now have __BYTE_ORDER__ defined
    # by the preprocessor.
    check += dedent('''\
        #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
        %ENDIANNESS "little"
        #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
        %ENDIANNESS "big"
        #endif
    ''')

    result = try_preprocess(compiler, language, check)

    if not result:
        raise FatalCheckError(
            'Unknown compiler or compiler not supported.')

    # Metadata emitted by preprocessors such as GCC with LANG=ja_JP.utf-8 may
    # have non-ASCII characters. Treat the output as bytearray.
    data = {}
    for line in result.splitlines():
        if line.startswith('%'):
            k, _, v = line.partition(' ')
            k = k.lstrip('%')
            data[k] = v.replace(' ', '').lstrip('"').rstrip('"')
            log.debug('%s = %s', k, data[k])

    try:
        type = CompilerType(data['COMPILER'])
    except Exception:
        raise FatalCheckError(
            'Unknown compiler or compiler not supported.')

    cplusplus = int(data.get('cplusplus', '0L').rstrip('L'))
    stdc_version = int(data.get('STDC_VERSION', '0L').rstrip('L'))

    version = data.get('VERSION')
    if version:
        version = Version(version)

    return namespace(
        type=type,
        version=version,
        cpu=data.get('CPU'),
        kernel=data.get('KERNEL'),
        endianness=data.get('ENDIANNESS'),
        os=data.get('OS'),
        language='C++' if cplusplus else 'C',
        language_version=cplusplus if cplusplus else stdc_version,
    )


def same_arch_different_bits():
    return (
        ('x86', 'x86_64'),
        ('ppc', 'ppc64'),
        ('sparc', 'sparc64'),
    )


@imports(_from='mozbuild.shellutil', _import='quote')
@imports(_from='mozbuild.configure.constants',
         _import='OS_preprocessor_checks')
def check_compiler(compiler, language, target):
    info = get_compiler_info(compiler, language)

    flags = []

    # Check language standards
    # --------------------------------------------------------------------
    if language != info.language:
        raise FatalCheckError(
            '`%s` is not a %s compiler.' % (quote(*compiler), language))

    # Note: We do a strict version check because there sometimes are backwards
    # incompatible changes in the standard, and not all code that compiles as
    # C99 compiles as e.g. C11 (as of writing, this is true of libnestegg, for
    # example)
    if info.language == 'C' and info.language_version != 199901:
        if info.type == 'clang-cl':
            flags.append('-Xclang')
        flags.append('-std=gnu99')

    cxx17_version = 201703
    if info.language == 'C++':
        if info.language_version != cxx17_version:
            # MSVC headers include C++17 features, but don't guard them
            # with appropriate checks.
            if info.type == 'clang-cl':
                flags.append('-Xclang')
                flags.append('-std=c++17')
            else:
                flags.append('-std=gnu++17')

    # Check compiler target
    # --------------------------------------------------------------------
    has_target = False
    if info.type == 'clang':
        # Add the target explicitly when the target is aarch64 macosx, because
        # the clang target is named differently, and we need to work around
        # https://github.com/rust-lang/rust-bindgen/issues/1871 and
        # https://github.com/alexcrichton/cc-rs/issues/542 so we always want
        # the target on the command line, even if the compiler would default to
        # that.
        if target.os == 'OSX' and target.cpu == 'aarch64':
            if '--target=arm64-apple-darwin' not in compiler:
                flags.append('--target=arm64-apple-darwin')
            has_target = True

        elif not info.kernel or info.kernel != target.kernel or \
                not info.endianness or info.endianness != target.endianness:
            flags.append('--target=%s' % target.toolchain)
            has_target = True

        # Add target flag when there is an OS mismatch (e.g. building for Android on
        # Linux). However, only do this if the target OS is in our whitelist, to
        # keep things the same on other platforms.
        elif target.os in OS_preprocessor_checks and (
                not info.os or info.os != target.os):
            flags.append('--target=%s' % target.toolchain)
            has_target = True

    if not has_target and (not info.cpu or info.cpu != target.cpu):
        same_arch = same_arch_different_bits()
        if (target.cpu, info.cpu) in same_arch:
            flags.append('-m32')
        elif (info.cpu, target.cpu) in same_arch:
            flags.append('-m64')
        elif info.type == 'clang-cl' and target.cpu == 'aarch64':
            flags.append('--target=%s' % target.toolchain)
        elif info.type == 'clang':
            flags.append('--target=%s' % target.toolchain)

    return namespace(
        type=info.type,
        version=info.version,
        target_cpu=info.cpu,
        target_kernel=info.kernel,
        target_endianness=info.endianness,
        target_os=info.os,
        flags=flags,
    )


@imports(_from='__builtin__', _import='open')
@imports('json')
@imports('os')
def get_vc_paths(topsrcdir):
    def vswhere(args):
        program_files = (os.environ.get('PROGRAMFILES(X86)') or
                         os.environ.get('PROGRAMFILES'))
        if not program_files:
            return []
        vswhere = os.path.join(program_files, 'Microsoft Visual Studio',
                               'Installer', 'vswhere.exe')
        if not os.path.exists(vswhere):
            return []
        return json.loads(check_cmd_output(vswhere, '-format', 'json', *args))

    for install in vswhere(['-products', '*', '-requires', 'Microsoft.VisualStudio.Component.VC.Tools.x86.x64']):
        path = install['installationPath']
        tools_version = open(os.path.join(
            path, r'VC\Auxiliary\Build\Microsoft.VCToolsVersion.default.txt'), 'r').read().strip()
        tools_path = os.path.join(
            path, r'VC\Tools\MSVC', tools_version)
        yield (Version(install['installationVersion']), tools_path)


@depends(host)
def host_is_windows(host):
    if host.kernel == 'WINNT':
        return True


js_option('--with-visual-studio-version', nargs=1,
          choices=('2017',), when=host_is_windows,
          help='Select a specific Visual Studio version to use')


@depends('--with-visual-studio-version', when=host_is_windows)
def vs_major_version(value):
    if value:
        return {'2017': 15}[value[0]]


js_option(env='VC_PATH', nargs=1, when=host_is_windows,
          help='Path to the Microsoft Visual C/C++ compiler')


@depends(host, vs_major_version, check_build_environment, 'VC_PATH',
         '--with-visual-studio-version', when=host_is_windows)
@imports(_from='__builtin__', _import='sorted')
@imports(_from='operator', _import='itemgetter')
def vc_compiler_paths_for_version(host, vs_major_version, env, vc_path, vs_release_name):
    if vc_path and vs_release_name:
        die('VC_PATH and --with-visual-studio-version cannot be used together.')
    if vc_path:
        # Use an arbitrary version, it doesn't matter.
        all_versions = [(Version('15'), vc_path[0])]
    else:
        all_versions = sorted(get_vc_paths(env.topsrcdir), key=itemgetter(0))
    if not all_versions:
        return
    if vs_major_version:
        versions = [d for (v, d) in all_versions if v.major ==
                    vs_major_version]
        if not versions:
            die('Visual Studio %s could not be found!' % vs_release_name)
        path = versions[0]
    else:
        # Choose the newest version.
        path = all_versions[-1][1]
    host_dir = {
        'x86_64': 'HostX64',
        'x86': 'HostX86',
    }.get(host.cpu)
    if host_dir:
        path = os.path.join(path, 'bin', host_dir)
        return {
            'x64': [os.path.join(path, 'x64')],
            # The cross toolchains require DLLs from the native x64 toolchain.
            'x86': [os.path.join(path, 'x86'), os.path.join(path, 'x64')],
            'arm64': [os.path.join(path, 'arm64'), os.path.join(path, 'x64')],
        }


@template
def vc_compiler_path_for(host_or_target):
    @depends(host_or_target, vc_compiler_paths_for_version,
             when=host_is_windows)
    def vc_compiler_path(target, paths):
        vc_target = {
            'x86': 'x86',
            'x86_64': 'x64',
            'arm': 'arm',
            'aarch64': 'arm64'
        }.get(target.cpu)
        if not paths:
            return
        return paths.get(vc_target)
    return vc_compiler_path


vc_compiler_path = vc_compiler_path_for(target)
host_vc_compiler_path = vc_compiler_path_for(host)


@dependable
@imports('os')
@imports(_from='os', _import='environ')
def original_path():
    return environ['PATH'].split(os.pathsep)


@template
def toolchain_search_path_for(host_or_target):
    arch_alias, vc_path = {
        host: ('host', host_vc_compiler_path),
        target: ('target', vc_compiler_path),
    }[host_or_target]

    @depends(dependable(arch_alias), vc_path, original_path, developer_options,
             mozbuild_state_path)
    @imports('os')
    @imports(_from='os', _import='environ')
    def toolchain_search_path(arch_alias, vc_compiler_path, original_path,
                              developer_options, mozbuild_state_path):
        result = list(original_path)

        if vc_compiler_path:
            # The second item, if there is one, is necessary to have in $PATH for
            # Windows to load the required DLLs from there.
            if len(vc_compiler_path) > 1:
                environ['PATH'] = os.pathsep.join(result + vc_compiler_path[1:])

            # The first item is where the programs are going to be
            result.append(vc_compiler_path[0])

        # Also add in the location to which `mach bootstrap` or
        # `mach artifact toolchain` installs clang, cbindgen, etc.
        bootstrapped = [
            os.path.join(mozbuild_state_path, *rest) for rest in (
                ['clang', 'bin'],
                ['cbindgen'],
                ['dump_syms'],
                ['nasm'],
                ['lucetc'],
            )]

        # Also add the rustup install directory for cargo/rustc.
        cargo_home = environ.get('CARGO_HOME', '')
        if cargo_home:
            cargo_home = os.path.abspath(cargo_home)
        else:
            cargo_home = os.path.expanduser(os.path.join('~', '.cargo'))
        rustup_path = os.path.join(cargo_home, 'bin')
        result.append(rustup_path)

        if developer_options:
            log.debug('Prioritizing mozbuild state dir in {} toolchain path because '
                      'you are not building in release mode.'.format(arch_alias))
            search_path = bootstrapped + result
        else:
            log.debug('Prioritizing system over mozbuild state dir in {} '
                      'toolchain path because you are building in '
                      'release mode.'.format(arch_alias))
            search_path = result + bootstrapped

        log.debug('Search path for {} toolchain: {}'.format(arch_alias, search_path))
        return search_path
    return toolchain_search_path


toolchain_search_path = toolchain_search_path_for(target)
host_toolchain_search_path = toolchain_search_path_for(host)


# As a workaround until bug 1516228 and bug 1516253 are fixed, set the PATH
# variable for the build to contain the toolchain search path.
@depends(toolchain_search_path, host_toolchain_search_path)
@imports('os')
@imports(_from='os', _import='environ')
def altered_path(toolchain_search_path, host_toolchain_search_path):
    path = environ['PATH'].split(os.pathsep)
    altered_path = list(toolchain_search_path)
    for p in host_toolchain_search_path:
        if p not in altered_path:
            altered_path.append(p)
    for p in path:
        if p not in altered_path:
            altered_path.append(p)
    return os.pathsep.join(altered_path)


set_config('PATH', altered_path)


@template
def default_c_compilers(host_or_target, other_c_compiler=None):
    '''Template defining the set of default C compilers for the host and
    target platforms.
    `host_or_target` is either `host` or `target` (the @depends functions
    from init.configure.
    `other_c_compiler` is the `target` C compiler when `host_or_target` is `host`.
    '''
    assert host_or_target in {host, target}

    other_c_compiler = () if other_c_compiler is None else (other_c_compiler,)

    @depends(host_or_target, target, toolchain_prefix, *other_c_compiler)
    def default_c_compilers(host_or_target, target, toolchain_prefix,
                            *other_c_compiler):
        if host_or_target.kernel == 'WINNT':
            supported = types = ('clang-cl', 'clang')
        elif host_or_target.kernel == 'Darwin':
            types = ('clang',)
            supported = ('clang', 'gcc')
        else:
            supported = types = ('clang', 'gcc')

        info = other_c_compiler[0] if other_c_compiler else None
        if info and info.type in supported:
            # When getting default C compilers for the host, we prioritize the
            # same compiler as the target C compiler.
            prioritized = info.compiler
            if info.type == 'gcc':
                same_arch = same_arch_different_bits()
                if (target.cpu != host_or_target.cpu and
                        (target.cpu, host_or_target.cpu) not in same_arch and
                        (host_or_target.cpu, target.cpu) not in same_arch):
                    # If the target C compiler is GCC, and it can't be used with
                    # -m32/-m64 for the host, it's probably toolchain-prefixed,
                    # so we prioritize a raw 'gcc' instead.
                    prioritized = info.type

            types = [prioritized] + [t for t in types if t != info.type]

        gcc = ('gcc',)
        if toolchain_prefix and host_or_target is target:
            gcc = tuple('%sgcc' % p for p in toolchain_prefix) + gcc

        result = []
        for type in types:
            if type == 'gcc':
                result.extend(gcc)
            else:
                result.append(type)

        return tuple(result)

    return default_c_compilers


@template
def default_cxx_compilers(c_compiler, other_c_compiler=None, other_cxx_compiler=None):
    '''Template defining the set of default C++ compilers for the host and
    target platforms.
    `c_compiler` is the @depends function returning a Compiler instance for
    the desired platform.

    Because the build system expects the C and C++ compilers to be from the
    same compiler suite, we derive the default C++ compilers from the C
    compiler that was found if none was provided.

    We also factor in the target C++ compiler when getting the default host
    C++ compiler, using the target C++ compiler if the host and target C
    compilers are the same.
    '''

    assert (other_c_compiler is None) == (other_cxx_compiler is None)
    if other_c_compiler is not None:
        other_compilers = (other_c_compiler, other_cxx_compiler)
    else:
        other_compilers = ()

    @depends(c_compiler, *other_compilers)
    def default_cxx_compilers(c_compiler, *other_compilers):
        if other_compilers:
            other_c_compiler, other_cxx_compiler = other_compilers
            if other_c_compiler.compiler == c_compiler.compiler:
                return (other_cxx_compiler.compiler,)

        dir = os.path.dirname(c_compiler.compiler)
        file = os.path.basename(c_compiler.compiler)

        if c_compiler.type == 'gcc':
            return (os.path.join(dir, file.replace('gcc', 'g++')),)

        if c_compiler.type == 'clang':
            return (os.path.join(dir, file.replace('clang', 'clang++')),)

        return (c_compiler.compiler,)

    return default_cxx_compilers


@template
def provided_program(env_var, when=None):
    '''Template handling cases where a program can be specified either as a
    path or as a path with applicable arguments.
    '''

    @depends_if(env_var, when=when)
    @imports(_from='itertools', _import='takewhile')
    @imports(_from='mozbuild.shellutil', _import='split', _as='shell_split')
    def provided(cmd):
        # Assume the first dash-prefixed item (and any subsequent items) are
        # command-line options, the item before the dash-prefixed item is
        # the program we're looking for, and anything before that is a wrapper
        # of some kind (e.g. sccache).
        cmd = shell_split(cmd[0])

        without_flags = list(takewhile(lambda x: not x.startswith('-'), cmd))

        return namespace(
            wrapper=without_flags[:-1],
            program=without_flags[-1],
            flags=cmd[len(without_flags):],
        )

    return provided


def prepare_flags(host_or_target, macos_sdk):
    if macos_sdk and host_or_target.os == 'OSX':
        return ['-isysroot', macos_sdk]
    return []


def minimum_gcc_version():
    return Version('7.1.0')


@template
def compiler(language, host_or_target, c_compiler=None, other_compiler=None,
             other_c_compiler=None):
    '''Template handling the generic base checks for the compiler for the
    given `language` on the given platform (`host_or_target`).
    `host_or_target` is either `host` or `target` (the @depends functions
    from init.configure.
    When the language is 'C++', `c_compiler` is the result of the `compiler`
    template for the language 'C' for the same `host_or_target`.
    When `host_or_target` is `host`, `other_compiler` is the result of the
    `compiler` template for the same `language` for `target`.
    When `host_or_target` is `host` and the language is 'C++',
    `other_c_compiler` is the result of the `compiler` template for the
    language 'C' for `target`.
    '''
    assert host_or_target in {host, target}
    assert language in ('C', 'C++')
    assert language == 'C' or c_compiler is not None
    assert host_or_target is target or other_compiler is not None
    assert language == 'C' or host_or_target is target or \
        other_c_compiler is not None

    host_or_target_str = {
        host: 'host',
        target: 'target',
    }[host_or_target]

    var = {
        ('C', target): 'CC',
        ('C++', target): 'CXX',
        ('C', host): 'HOST_CC',
        ('C++', host): 'HOST_CXX',
    }[language, host_or_target]

    default_compilers = {
        'C': lambda: default_c_compilers(host_or_target, other_compiler),
        'C++': lambda: default_cxx_compilers(c_compiler, other_c_compiler, other_compiler),
    }[language]()

    what = 'the %s %s compiler' % (host_or_target_str, language)

    option(env=var, nargs=1, help='Path to %s' % what)

    # Handle the compiler given by the user through one of the CC/CXX/HOST_CC/
    # HOST_CXX variables.
    provided_compiler = provided_program(var)

    search_path = {
        host: host_toolchain_search_path,
        target: toolchain_search_path,
    }[host_or_target]

    # Normally, we'd use `var` instead of `_var`, but the interaction with
    # old-configure complicates things, and for now, we a) can't take the plain
    # result from check_prog as CC/CXX/HOST_CC/HOST_CXX and b) have to let
    # old-configure AC_SUBST it (because it's autoconf doing it, not us)
    compiler = check_prog('_%s' % var, what=what, progs=default_compilers,
                          input=provided_compiler.program,
                          paths=search_path)

    @depends(compiler, provided_compiler, compiler_wrapper, host_or_target, macos_sdk)
    @checking('whether %s can be used' % what, lambda x: bool(x))
    @imports(_from='mozbuild.shellutil', _import='quote')
    def valid_compiler(compiler, provided_compiler, compiler_wrapper,
                       host_or_target, macos_sdk):
        wrapper = list(compiler_wrapper or ())
        flags = prepare_flags(host_or_target, macos_sdk)
        if provided_compiler:
            provided_wrapper = list(provided_compiler.wrapper)
            # When doing a subconfigure, the compiler is set by old-configure
            # and it contains the wrappers from --with-compiler-wrapper and
            # --with-ccache.
            if provided_wrapper[:len(wrapper)] == wrapper:
                provided_wrapper = provided_wrapper[len(wrapper):]
            wrapper.extend(provided_wrapper)
            flags.extend(provided_compiler.flags)

        info = check_compiler(wrapper + [compiler] + flags, language,
                              host_or_target)

        # Check that the additional flags we got are enough to not require any
        # more flags. If we get an exception, just ignore it; it's liable to be
        # invalid command-line flags, which means the compiler we're checking
        # doesn't support those command-line flags and will fail one or more of
        # the checks below.
        try:
            if info.flags:
                flags += info.flags
                info = check_compiler(wrapper + [compiler] + flags, language,
                                      host_or_target)
        except FatalCheckError:
            pass

        if not info.target_cpu or info.target_cpu != host_or_target.cpu:
            raise FatalCheckError(
                '%s %s compiler target CPU (%s) does not match --%s CPU (%s)'
                % (host_or_target_str.capitalize(), language,
                   info.target_cpu or 'unknown', host_or_target_str,
                   host_or_target.raw_cpu))

        if not info.target_kernel or (info.target_kernel !=
                                      host_or_target.kernel):
            raise FatalCheckError(
                '%s %s compiler target kernel (%s) does not match --%s kernel (%s)'
                % (host_or_target_str.capitalize(), language,
                   info.target_kernel or 'unknown', host_or_target_str,
                   host_or_target.kernel))

        if not info.target_endianness or (info.target_endianness !=
                                          host_or_target.endianness):
            raise FatalCheckError(
                '%s %s compiler target endianness (%s) does not match --%s '
                'endianness (%s)'
                % (host_or_target_str.capitalize(), language,
                   info.target_endianness or 'unknown', host_or_target_str,
                   host_or_target.endianness))

        # Compiler version checks
        # ===================================================
        # Check the compiler version here instead of in `compiler_version` so
        # that the `checking` message doesn't pretend the compiler can be used
        # to then bail out one line later.
        if info.type == 'gcc':
            if host_or_target.os == 'Android':
                raise FatalCheckError('GCC is not supported on Android.\n'
                                      'Please use clang from the Android NDK instead.')
            gcc_version = minimum_gcc_version()
            if info.version < gcc_version:
                raise FatalCheckError(
                    'Only GCC %d.%d or newer is supported (found version %s).'
                    % (gcc_version.major, gcc_version.minor, info.version))

        if info.type == 'clang-cl':
            if info.version < '8.0.0':
                raise FatalCheckError(
                    'Only clang-cl 8.0 or newer is supported (found version %s)'
                    % info.version)

        # If you want to bump the version check here search for
        # diagnose_if above, and see the associated comment.
        if info.type == 'clang' and not info.version:
            raise FatalCheckError(
                'Only clang/llvm 5.0 or newer is supported.')

        if info.flags:
            raise FatalCheckError(
                'Unknown compiler or compiler not supported.')

        return namespace(
            wrapper=wrapper,
            compiler=compiler,
            flags=flags,
            type=info.type,
            version=info.version,
            language=language,
        )

    @depends(valid_compiler)
    @checking('%s version' % what)
    def compiler_version(compiler):
        return compiler.version

    if language == 'C++':
        @depends(valid_compiler, c_compiler)
        def valid_compiler(compiler, c_compiler):
            if compiler.type != c_compiler.type:
                die('The %s C compiler is %s, while the %s C++ compiler is '
                    '%s. Need to use the same compiler suite.',
                    host_or_target_str, c_compiler.type,
                    host_or_target_str, compiler.type)

            if compiler.version != c_compiler.version:
                die('The %s C compiler is version %s, while the %s C++ '
                    'compiler is version %s. Need to use the same compiler '
                    'version.',
                    host_or_target_str, c_compiler.version,
                    host_or_target_str, compiler.version)
            return compiler

    # Set CC/CXX/HOST_CC/HOST_CXX for old-configure, which needs the wrapper
    # and the flags that were part of the user input for those variables to
    # be provided.
    add_old_configure_assignment(var, depends_if(valid_compiler)(
        lambda x: list(x.wrapper) + [x.compiler] + list(x.flags)))

    if host_or_target is target:
        add_old_configure_assignment('ac_cv_prog_%s' % var, depends_if(valid_compiler)(
            lambda x: list(x.wrapper) + [x.compiler] + list(x.flags)))
        # We check that it works in python configure already.
        add_old_configure_assignment('ac_cv_prog_%s_works' % var.lower(), 'yes')
        add_old_configure_assignment(
            'ac_cv_prog_%s_cross' % var.lower(),
            depends(cross_compiling)(lambda x: 'yes' if x else 'no'))
        gcc_like = depends(valid_compiler.type)(lambda x: 'yes' if x in ('gcc', 'clang') else 'no')
        add_old_configure_assignment('ac_cv_prog_%s_g' % var.lower(), gcc_like)
        if language == 'C':
            add_old_configure_assignment('ac_cv_prog_gcc', gcc_like)
        if language == 'C++':
            add_old_configure_assignment('ac_cv_prog_gxx', gcc_like)


    # Set CC_TYPE/CC_VERSION/HOST_CC_TYPE/HOST_CC_VERSION to allow
    # old-configure to do some of its still existing checks.
    if language == 'C':
        set_config(
            '%s_TYPE' % var, valid_compiler.type)
        add_old_configure_assignment(
            '%s_TYPE' % var, valid_compiler.type)
        set_config(
            '%s_VERSION' % var, depends(valid_compiler.version)(lambda v: str(v)))

    valid_compiler = compiler_class(valid_compiler, host_or_target)

    def compiler_error():
        raise FatalCheckError('Failed compiling a simple %s source with %s'
                              % (language, what))

    valid_compiler.try_compile(check_msg='%s works' % what,
                               onerror=compiler_error)

    set_config('%s_BASE_FLAGS' % var, valid_compiler.flags)

    # Set CPP/CXXCPP for both the build system and old-configure. We don't
    # need to check this works for preprocessing, because we already relied
    # on $CC -E/$CXX -E doing preprocessing work to validate the compiler
    # in the first place.
    if host_or_target is target:
        pp_var = {
            'C': 'CPP',
            'C++': 'CXXCPP',
        }[language]

        preprocessor = depends_if(valid_compiler)(
            lambda x: list(x.wrapper) + [x.compiler, '-E'] + list(x.flags))

        set_config(pp_var, preprocessor)
        add_old_configure_assignment(pp_var, preprocessor)

    if language == 'C':
        linker_var = {
            target: 'LD',
            host: 'HOST_LD',
        }[host_or_target]

        @deprecated_option(env=linker_var, nargs=1)
        def linker(value):
            if value:
                return value[0]

        @depends(linker)
        def unused_linker(linker):
            if linker:
                log.warning('The value of %s is not used by this build system.'
                            % linker_var)

    return valid_compiler


c_compiler = compiler('C', target)
cxx_compiler = compiler('C++', target, c_compiler=c_compiler)
host_c_compiler = compiler('C', host, other_compiler=c_compiler)
host_cxx_compiler = compiler('C++', host, c_compiler=host_c_compiler,
                             other_compiler=cxx_compiler,
                             other_c_compiler=c_compiler)

# Generic compiler-based conditions.
building_with_gcc = depends(c_compiler)(lambda info: info.type == 'gcc')


@depends(cxx_compiler, ccache_prefix)
@imports('os')
def cxx_is_icecream(info, ccache_prefix):
    if (os.path.islink(info.compiler) and os.path.basename(
            os.readlink(info.compiler)) == 'icecc'):
        return True
    if ccache_prefix and os.path.basename(ccache_prefix) == 'icecc':
        return True

set_config('CXX_IS_ICECREAM', cxx_is_icecream)


@depends(c_compiler)
def msvs_version(info):
    # clang-cl emulates the same version scheme as cl. And MSVS_VERSION needs to
    # be set for GYP on Windows.
    if info.type == 'clang-cl':
        return '2017'

    return ''


set_config('MSVS_VERSION', msvs_version)

include('compile-checks.configure')
include('arm.configure', when=depends(target.cpu)(lambda cpu: cpu == 'arm'))


@depends(host, host_os_kernel_major_version, target)
def needs_macos_sdk_headers_check(host, version, target):
    # Only an issue on Mac OS X 10.14 (and probably above).
    if host.kernel != 'Darwin' or target.kernel !='Darwin' or version < '18':
        return

    return True


@depends(cxx_compiler.try_run(header='#include_next <inttypes.h>',
                              check_msg='for macOS SDK headers',
                              when=needs_macos_sdk_headers_check),
         when=needs_macos_sdk_headers_check)
def check_have_mac_10_14_sdk(value):
    if value:
        return

    die('System inttypes.h not found. Please try running '
         '`open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg` '
         'and following the instructions to install the necessary headers')


@depends(have_64_bit,
         try_compile(body='static_assert(sizeof(void *) == 8, "")',
                     check_msg='for 64-bit OS'))
def check_have_64_bit(have_64_bit, compiler_have_64_bit):
    if have_64_bit != compiler_have_64_bit:
        configure_error('The target compiler does not agree with configure '
                        'about the target bitness.')


@depends(cxx_compiler, target)
def needs_libstdcxx_newness_check(cxx_compiler, target):
    # We only have to care about this on Linux and MinGW.
    if cxx_compiler.type == 'clang-cl':
        return

    if target.kernel not in ('Linux', 'WINNT'):
        return

    if target.os == 'Android':
        return

    return True


def die_on_old_libstdcxx():
    die('The libstdc++ in use is not new enough.  Please run '
        './mach bootstrap to update your compiler, or update your system '
        'libstdc++ installation.')

try_compile(includes=['cstddef'],
            body='\n'.join([
                # _GLIBCXX_RELEASE showed up in libstdc++ 7.
                '#if defined(__GLIBCXX__) && !defined(_GLIBCXX_RELEASE)',
                '#  error libstdc++ not new enough',
                '#endif',
                '#if defined(_GLIBCXX_RELEASE)',
                '#  if _GLIBCXX_RELEASE < %d' % minimum_gcc_version().major,
                '#    error libstdc++ not new enough',
                '#  else',
                '     (void) 0',
                '#  endif',
                '#endif',
            ]),
            check_msg='for new enough STL headers from libstdc++',
            when=needs_libstdcxx_newness_check,
            onerror=die_on_old_libstdcxx)


@depends(c_compiler, target)
def default_debug_flags(compiler_info, target):
    # Debug info is ON by default.
    if compiler_info.type == 'clang-cl':
        return '-Z7'
    elif target.kernel == 'WINNT' and compiler_info.type == 'clang':
        return '-g -gcodeview'
    return '-g'


option(env='MOZ_DEBUG_FLAGS',
       nargs=1,
       help='Debug compiler flags')

imply_option('--enable-debug-symbols',
             depends_if('--enable-debug')(lambda v: v))

js_option('--disable-debug-symbols',
          nargs='?',
          help='Disable debug symbols using the given compiler flags')

set_config('MOZ_DEBUG_SYMBOLS',
           depends_if('--enable-debug-symbols')(lambda _: True))


@depends('MOZ_DEBUG_FLAGS', '--enable-debug-symbols', default_debug_flags)
def debug_flags(env_debug_flags, enable_debug_flags, default_debug_flags):
    # If MOZ_DEBUG_FLAGS is set, and --enable-debug-symbols is set to a value,
    # --enable-debug-symbols takes precedence. Note, the value of
    # --enable-debug-symbols may be implied by --enable-debug.
    if len(enable_debug_flags):
        return enable_debug_flags[0]
    if env_debug_flags:
        return env_debug_flags[0]
    return default_debug_flags


set_config('MOZ_DEBUG_FLAGS', debug_flags)
add_old_configure_assignment('MOZ_DEBUG_FLAGS', debug_flags)


@depends(c_compiler)
def color_cflags(info):
    # We could test compiling with flags. By why incur the overhead when
    # color support should always be present in a specific toolchain
    # version?

    # Code for auto-adding this flag to compiler invocations needs to
    # determine if an existing flag isn't already present. That is likely
    # using exact string matching on the returned value. So if the return
    # value changes to e.g. "<x>=always", exact string match may fail and
    # multiple color flags could be added. So examine downstream consumers
    # before adding flags to return values.
    if info.type == 'gcc':
        return '-fdiagnostics-color'
    elif info.type == 'clang':
        return '-fcolor-diagnostics'
    else:
        return ''


set_config('COLOR_CFLAGS', color_cflags)

# Some standard library headers (notably bionic on Android) declare standard
# functions (e.g. getchar()) and also #define macros for those standard
# functions.  libc++ deals with this by doing something like the following
# (explanatory comments added):
#
#   #ifdef FUNC
#   // Capture the definition of FUNC.
#   inline _LIBCPP_INLINE_VISIBILITY int __libcpp_FUNC(...) { return FUNC(...); }
#   #undef FUNC
#   // Use a real inline definition.
#   inline _LIBCPP_INLINE_VISIBILITY int FUNC(...) { return _libcpp_FUNC(...); }
#   #endif
#
# _LIBCPP_INLINE_VISIBILITY is typically defined as:
#
#   __attribute__((__visibility__("hidden"), __always_inline__))
#
# Unfortunately, this interacts badly with our system header wrappers, as the:
#
#   #pragma GCC visibility push(default)
#
# that they do prior to including the actual system header is treated by the
# compiler as an explicit declaration of visibility on every function declared
# in the header.  Therefore, when the libc++ code above is encountered, it is
# as though the compiler has effectively seen:
#
#   int FUNC(...) __attribute__((__visibility__("default")));
#   int FUNC(...) __attribute__((__visibility__("hidden")));
#
# and the compiler complains about the mismatched visibility declarations.
#
# However, libc++ will only define _LIBCPP_INLINE_VISIBILITY if there is no
# existing definition.  We can therefore define it to the empty string (since
# we are properly managing visibility ourselves) and avoid this whole mess.
# Note that we don't need to do this with gcc, as libc++ detects gcc and
# effectively does the same thing we are doing here.
#
# _LIBCPP_ALWAYS_INLINE needs a similar workarounds, since it too declares
# hidden visibility.
#
# _LIBCPP_HIDE_FROM_ABI is a macro in libc++ versions in NDKs >=r19.  It too
# declares hidden visibility, but it also declares functions as excluded from
# explicit instantiation (roughly: the function can be unused in the current
# compilation, but does not then trigger an actual definition of the function;
# it is assumed the real definition comes from elsewhere).  We need to replicate
# this setup.


@depends(c_compiler, target)
def libcxx_override_visibility(c_compiler, target):
    if c_compiler.type == 'clang' and target.os == 'Android':
        return namespace(
            empty='',
            hide_from_abi='__attribute__((__exclude_from_explicit_instantiation__))',
        )


set_define('_LIBCPP_INLINE_VISIBILITY', libcxx_override_visibility.empty)
set_define('_LIBCPP_ALWAYS_INLINE', libcxx_override_visibility.empty)

set_define('_LIBCPP_HIDE_FROM_ABI', libcxx_override_visibility.hide_from_abi)

@depends(target, check_build_environment)
def visibility_flags(target, env):
    if target.os != 'WINNT':
        if target.kernel == 'Darwin':
            return ('-fvisibility=hidden', '-fvisibility-inlines-hidden')
        return ('-I%s/system_wrappers' % os.path.join(env.dist),
                '-include',
                '%s/config/gcc_hidden.h' % env.topsrcdir)


@depends(target, visibility_flags)
def wrap_system_includes(target, visibility_flags):
    if visibility_flags and target.kernel != 'Darwin':
        return True


set_define('HAVE_VISIBILITY_HIDDEN_ATTRIBUTE',
           depends(visibility_flags)(lambda v: bool(v) or None))
set_define('HAVE_VISIBILITY_ATTRIBUTE',
           depends(visibility_flags)(lambda v: bool(v) or None))
set_config('WRAP_SYSTEM_INCLUDES', wrap_system_includes)
set_config('VISIBILITY_FLAGS', visibility_flags)


@template
def depend_cflags(host_or_target_c_compiler):
    @depends(host_or_target_c_compiler)
    def depend_cflags(host_or_target_c_compiler):
        if host_or_target_c_compiler.type != 'clang-cl':
            return ['-MD', '-MP', '-MF $(MDDEPDIR)/$(@F).pp']
        else:
            # clang-cl doesn't accept the normal -MD -MP -MF options that clang
            # does, but the underlying cc1 binary understands how to generate
            # dependency files.  These options are based on analyzing what the
            # normal clang driver sends to cc1 when given the "correct"
            # dependency options.
            return [
                '-Xclang', '-MP',
                '-Xclang', '-dependency-file',
                '-Xclang', '$(MDDEPDIR)/$(@F).pp',
                '-Xclang', '-MT',
                '-Xclang', '$@'
            ]

    return depend_cflags


set_config('_DEPEND_CFLAGS', depend_cflags(c_compiler))
set_config('_HOST_DEPEND_CFLAGS', depend_cflags(host_c_compiler))


@depends(c_compiler)
def preprocess_option(compiler):
    # The uses of PREPROCESS_OPTION depend on the spacing for -o/-Fi.
    if compiler.type in ('gcc', 'clang'):
        return '-E -o '
    else:
        return '-P -Fi'


set_config('PREPROCESS_OPTION', preprocess_option)


# We only want to include windows.configure when we are compiling on
# Windows, or for Windows.


@depends(target, host)
def is_windows(target, host):
    return host.kernel == 'WINNT' or target.kernel == 'WINNT'


include('windows.configure', when=is_windows)


# On Power ISA, determine compiler flags for VMX, VSX and VSX-3.

set_config('PPC_VMX_FLAGS',
           ['-maltivec'],
           when=depends(target.cpu)(lambda cpu: cpu.startswith('ppc')))

set_config('PPC_VSX_FLAGS',
           ['-mvsx'],
           when=depends(target.cpu)(lambda cpu: cpu.startswith('ppc')))

set_config('PPC_VSX3_FLAGS',
           ['-mvsx','-mcpu=power9'],
           when=depends(target.cpu)(lambda cpu: cpu.startswith('ppc')))

# ASAN
# ==============================================================

js_option('--enable-address-sanitizer', help='Enable Address Sanitizer')


@depends(when='--enable-address-sanitizer')
def asan():
    return True


add_old_configure_assignment('MOZ_ASAN', asan)

# MSAN
# ==============================================================

js_option('--enable-memory-sanitizer', help='Enable Memory Sanitizer')


@depends(when='--enable-memory-sanitizer')
def msan():
    return True


add_old_configure_assignment('MOZ_MSAN', msan)

# TSAN
# ==============================================================

js_option('--enable-thread-sanitizer', help='Enable Thread Sanitizer')


@depends(when='--enable-thread-sanitizer')
def tsan():
    return True


add_old_configure_assignment('MOZ_TSAN', tsan)

# UBSAN
# ==============================================================

js_option('--enable-undefined-sanitizer',
          nargs='*',
          help='Enable UndefinedBehavior Sanitizer')

@depends_if('--enable-undefined-sanitizer')
def ubsan(options):
    default_checks = [
        'bool',
        'bounds',
        'enum',
        'integer-divide-by-zero',
        'object-size',
        'pointer-overflow',
        'return',
        'vla-bound',
    ]

    checks = options if len(options) else default_checks

    return ','.join(checks)

add_old_configure_assignment('MOZ_UBSAN_CHECKS', ubsan)


js_option('--enable-signed-overflow-sanitizer',
          help='Enable UndefinedBehavior Sanitizer (Signed Integer Overflow Parts)')


@depends(when='--enable-signed-overflow-sanitizer')
def ub_signed_overflow_san():
    return True


add_old_configure_assignment('MOZ_SIGNED_OVERFLOW_SANITIZE', ub_signed_overflow_san)


js_option('--enable-unsigned-overflow-sanitizer',
          help='Enable UndefinedBehavior Sanitizer (Unsigned Integer Overflow Parts)')


@depends(when='--enable-unsigned-overflow-sanitizer')
def ub_unsigned_overflow_san():
    return True


add_old_configure_assignment('MOZ_UNSIGNED_OVERFLOW_SANITIZE', ub_unsigned_overflow_san)

# Security Hardening
# ==============================================================

option('--enable-hardening', env='MOZ_SECURITY_HARDENING',
       help='Enables security hardening compiler options')


# This function is a bit confusing. It adds or removes hardening flags in
# three stuations: if --enable-hardening is passed; if --disable-hardening
# is passed, and if no flag is passed.
#
# At time of this comment writing, all flags are actually added in the
# default no-flag case; making --enable-hardening the same as omitting the
# flag. --disable-hardening will omit the security flags. (However, not all
# possible security flags will be omitted by --disable-hardening, as many are
# compiler-default options we do not explicitly enable.)
@depends('--enable-hardening', '--enable-address-sanitizer',
         '--enable-debug', '--enable-optimize', c_compiler, target)
def security_hardening_cflags(hardening_flag, asan, debug, optimize, c_compiler,
                              target):
    compiler_is_gccish = c_compiler.type in ('gcc', 'clang')
    mingw_clang = c_compiler.type == 'clang' and target.os == 'WINNT'

    flags = []
    ldflags = []
    js_flags = []
    js_ldflags = []

    # ----------------------------------------------------------
    # If hardening is explicitly enabled, or not explicitly disabled
    if hardening_flag.origin == "default" or hardening_flag:
        # FORTIFY_SOURCE ------------------------------------
        # Require optimization for FORTIFY_SOURCE. See Bug 1417452
        # Also, undefine it before defining it just in case a distro adds it, see Bug 1418398
        if compiler_is_gccish and optimize and not asan:
            # Don't enable FORTIFY_SOURCE on Android on the top-level, but do enable in js/
            if target.os != 'Android':
                flags.append("-U_FORTIFY_SOURCE")
                flags.append("-D_FORTIFY_SOURCE=2")
            js_flags.append("-U_FORTIFY_SOURCE")
            js_flags.append("-D_FORTIFY_SOURCE=2")
            if mingw_clang:
                # mingw-clang needs to link in ssp which is not done by default
                ldflags.append('-lssp')
                js_ldflags.append('-lssp')

        # fstack-protector ------------------------------------
        # Enable only if hardening is not disabled and ASAN is
        # not on as ASAN will catch the crashes for us
        if compiler_is_gccish and not asan:
            flags.append("-fstack-protector-strong")
            ldflags.append("-fstack-protector-strong")
            js_flags.append("-fstack-protector-strong")
            js_ldflags.append("-fstack-protector-strong")

        # ftrivial-auto-var-init ------------------------------
        # Initialize local variables with a 0xAA pattern in clang debug builds.
        # Linux32 fails some xpcshell tests with -ftrivial-auto-var-init
        linux32 = target.kernel == 'Linux' and target.cpu == 'x86'
        if (c_compiler.type == 'clang' or c_compiler.type == 'clang-cl') and \
            c_compiler.version >= '8' and debug and not linux32:
            if c_compiler.type == 'clang-cl':
                flags.append('-Xclang')
                js_flags.append('-Xclang')
            flags.append('-ftrivial-auto-var-init=pattern')
            js_flags.append('-ftrivial-auto-var-init=pattern')

        # ASLR ------------------------------------------------
        # ASLR (dynamicbase) is enabled by default in clang-cl; but the
        # mingw-clang build requires it to be explicitly enabled
        if mingw_clang:
            ldflags.append("-Wl,--dynamicbase")
            js_ldflags.append("-Wl,--dynamicbase")

        # Control Flow Guard (CFG) ----------------------------
        if c_compiler.type == 'clang-cl' and c_compiler.version >= '8' and \
           (target.cpu != 'aarch64' or c_compiler.version >= '8.0.1'):
            if target.cpu == 'aarch64' and c_compiler.version >= '10.0.0':
                # The added checks in clang 10 make arm64 builds crash. (Bug 1639318)
                flags.append("-guard:cf,nochecks")
                js_flags.append("-guard:cf,nochecks")
            else:
                flags.append("-guard:cf")
                js_flags.append("-guard:cf")
            # nolongjmp is needed because clang doesn't emit the CFG tables of
            # setjmp return addresses https://bugs.llvm.org/show_bug.cgi?id=40057
            ldflags.append("-guard:cf,nolongjmp")
            js_ldflags.append("-guard:cf,nolongjmp")

    # ----------------------------------------------------------
    # If ASAN _is_ on, undefine FORTIFY_SOURCE just to be safe
    if asan:
        flags.append("-U_FORTIFY_SOURCE")
        js_flags.append("-U_FORTIFY_SOURCE")

    # fno-common -----------------------------------------
    # Do not merge variables for ASAN; can detect some subtle bugs
    if asan:
        # clang-cl does not recognize the flag, it must be passed down to clang
        if c_compiler.type == 'clang-cl':
            flags.append("-Xclang")
        flags.append("-fno-common")

    return namespace(
        flags=flags,
        ldflags=ldflags,
        js_flags=js_flags,
        js_ldflags=js_ldflags,
    )


set_config('MOZ_HARDENING_CFLAGS', security_hardening_cflags.flags)
set_config('MOZ_HARDENING_LDFLAGS', security_hardening_cflags.ldflags)
set_config('MOZ_HARDENING_CFLAGS_JS', security_hardening_cflags.js_flags)
set_config('MOZ_HARDENING_LDFLAGS_JS', security_hardening_cflags.js_ldflags)


# Frame pointers
# ==============================================================
@depends(c_compiler)
def frame_pointer_flags(compiler):
    if compiler.type == 'clang-cl':
        return namespace(
            enable=['-Oy-'],
            disable=['-Oy'],
        )
    return namespace(
        enable=['-fno-omit-frame-pointer', '-funwind-tables'],
        disable=['-fomit-frame-pointer', '-funwind-tables'],
    )


@depends(moz_optimize.optimize, moz_debug, target,
         '--enable-memory-sanitizer', '--enable-address-sanitizer',
         '--enable-undefined-sanitizer')
def frame_pointer_default(optimize, debug, target, msan, asan, ubsan):
    return bool(not optimize or debug or msan or asan or ubsan or \
        (target.os == 'WINNT' and target.cpu in ('x86', 'aarch64')))


js_option('--enable-frame-pointers', default=frame_pointer_default,
          help='{Enable|Disable} frame pointers')


@depends('--enable-frame-pointers', frame_pointer_flags)
def frame_pointer_flags(enable, flags):
    if enable:
        return flags.enable
    return flags.disable


set_config('MOZ_FRAMEPTR_FLAGS', frame_pointer_flags)


# nasm detection
# ==============================================================
nasm = check_prog('NASM', ['nasm'], allow_missing=True, paths=toolchain_search_path)


@depends_if(nasm)
@checking('nasm version')
def nasm_version(nasm):
    (retcode, stdout, _) = get_cmd_output(nasm, '-v')
    if retcode:
        # mac stub binary
        return None

    version = stdout.splitlines()[0].split()[2]
    return Version(version)


@depends_if(nasm_version)
def nasm_major_version(nasm_version):
    return str(nasm_version.major)


@depends_if(nasm_version)
def nasm_minor_version(nasm_version):
    return str(nasm_version.minor)


set_config('NASM_MAJOR_VERSION', nasm_major_version)
set_config('NASM_MINOR_VERSION', nasm_minor_version)


@depends(nasm, target)
def nasm_asflags(nasm, target):
    if nasm:
        asflags = {
            ('OSX', 'x86'): ['-f', 'macho32'],
            ('OSX', 'x86_64'): ['-f', 'macho64'],
            ('WINNT', 'x86'): ['-f', 'win32'],
            ('WINNT', 'x86_64'): ['-f', 'win64'],
        }.get((target.os, target.cpu), None)
        if asflags is None:
            # We're assuming every x86 platform we support that's
            # not Windows or Mac is ELF.
            if target.cpu == 'x86':
                asflags = ['-f', 'elf32']
            elif target.cpu == 'x86_64':
                asflags = ['-f', 'elf64']
        return asflags


set_config('NASM_ASFLAGS', nasm_asflags)

@depends(nasm_asflags)
def have_nasm(value):
    if value:
        return True


@depends(yasm_asflags)
def have_yasm(yasm_asflags):
    if yasm_asflags:
        return True

set_config('HAVE_NASM', have_nasm)

set_config('HAVE_YASM', have_yasm)
# Until the YASM variable is not necessary in old-configure.
add_old_configure_assignment('YASM', have_yasm)


# Code Coverage
# ==============================================================

js_option('--enable-coverage', env='MOZ_CODE_COVERAGE',
          help='Enable code coverage')


@depends('--enable-coverage')
def code_coverage(value):
    if value:
        return True


set_config('MOZ_CODE_COVERAGE', code_coverage)
set_define('MOZ_CODE_COVERAGE', code_coverage)

@depends(target, c_compiler, vc_path, check_build_environment, when=code_coverage)
@imports('os')
@imports('re')
@imports(_from='__builtin__', _import='open')
def coverage_cflags(target, c_compiler, vc_path, build_env):
    cflags = ['--coverage']

    # clang 11 no longer accepts this flag (its behavior became the default)
    if c_compiler.type in ('clang', 'clang-cl') and c_compiler.version < '11.0.0':
        cflags += [
            '-Xclang', '-coverage-no-function-names-in-data',
        ]

    if target.os == 'WINNT' and c_compiler.type == 'clang-cl':
        # The Visual Studio directory is the parent of the Visual C++ directory.
        vs_path = os.path.dirname(vc_path)

        # We need to get the real path of Visual Studio, which can be in a
        # symlinked directory (for example, on automation).
        vs_path = os.path.realpath(vs_path)

        cflags += [
            '-fprofile-exclude-files=^{}.*$'.format(re.escape(vs_path)),
        ]

    response_file_path = os.path.join(build_env.topobjdir, 'code_coverage_cflags')

    with open(response_file_path, 'w') as f:
        f.write(' '.join(cflags))

    return ['@{}'.format(response_file_path)]

set_config('COVERAGE_CFLAGS', coverage_cflags)

# ==============================================================

option(env='RUSTFLAGS',
       nargs=1,
       help='Rust compiler flags')
set_config('RUSTFLAGS', depends('RUSTFLAGS')(lambda flags: flags))


# Rust compiler flags
# ==============================================================

js_option(env='RUSTC_OPT_LEVEL',
          nargs=1,
          help='Rust compiler optimization level (-C opt-level=%s)')

# --enable-release kicks in full optimizations.
imply_option('RUSTC_OPT_LEVEL', '2', when='--enable-release')


@depends('RUSTC_OPT_LEVEL', moz_optimize)
def rustc_opt_level(opt_level_option, moz_optimize):
    if opt_level_option:
        return opt_level_option[0]
    else:
        return '1' if moz_optimize.optimize else '0'


@depends(rustc_opt_level, debug_rust, '--enable-debug-symbols', '--enable-frame-pointers')
def rust_compile_flags(opt_level, debug_rust, debug_symbols, frame_pointers):
    # Cargo currently supports only two interesting profiles for building:
    # development and release. Those map (roughly) to --enable-debug and
    # --disable-debug in Gecko, respectively.
    #
    # But we'd also like to support an additional axis of control for
    # optimization level. Since Cargo only supports 2 profiles, we're in
    # a bit of a bind.
    #
    # Code here derives various compiler options given other configure options.
    # The options defined here effectively override defaults specified in
    # Cargo.toml files.

    debug_assertions = None
    debug_info = None

    # opt-level=0 implies -C debug-assertions, which may not be desired
    # unless Rust debugging is enabled.
    if opt_level == '0' and not debug_rust:
        debug_assertions = False

    if debug_symbols:
        debug_info = '2'

    opts = []

    if opt_level is not None:
        opts.append('opt-level=%s' % opt_level)
    if debug_assertions is not None:
        opts.append('debug-assertions=%s' %
                    ('yes' if debug_assertions else 'no'))
    if debug_info is not None:
        opts.append('debuginfo=%s' % debug_info)
    if frame_pointers:
        opts.append('force-frame-pointers=yes')

    flags = []
    for opt in opts:
        flags.extend(['-C', opt])

    return flags


# Rust incremental compilation
# ==============================================================


js_option('--disable-cargo-incremental',
          help='Disable incremental rust compilation.')

@depends(rustc_opt_level, debug_rust, 'MOZ_AUTOMATION', code_coverage,
         '--disable-cargo-incremental', using_sccache, 'RUSTC_WRAPPER')
@imports('os')
def cargo_incremental(opt_level, debug_rust, automation, code_coverage,
                      enabled, using_sccache, rustc_wrapper):
    """Return a value for the CARGO_INCREMENTAL environment variable."""

    if not enabled:
        return '0'

    # We never want to use incremental compilation in automation.  sccache
    # handles our automation use case much better than incremental compilation
    # would.
    if automation:
        return '0'

    # Coverage instrumentation doesn't play well with incremental compilation
    # https://github.com/rust-lang/rust/issues/50203.
    if code_coverage:
        return '0'

    # Incremental compilation doesn't work as well as it should, and if we're
    # using sccache, it's better to use sccache than incremental compilation.
    if not using_sccache and rustc_wrapper:
        rustc_wrapper = os.path.basename(rustc_wrapper[0])
        if os.path.splitext(rustc_wrapper)[0].lower() == 'sccache':
            using_sccache = True
    if using_sccache:
        return '0'

    # Incremental compilation is automatically turned on for debug builds, so
    # we don't need to do anything special here.
    if debug_rust:
        return

    # --enable-release automatically sets -O2 for Rust code, and people can
    # set RUSTC_OPT_LEVEL to 2 or even 3 if they want to profile Rust code.
    # Let's assume that if Rust code is using -O2 or higher, we shouldn't
    # be using incremental compilation, because we'd be imposing a
    # significant runtime cost.
    if opt_level not in ('0', '1'):
        return

    # We're clear to use incremental compilation!
    return '1'


set_config('CARGO_INCREMENTAL', cargo_incremental)

# Linker detection
# ==============================================================
# The policy is as follows:
# For Windows:
# - the linker is picked via the LINKER environment variable per windows.configure,
#   but ought to be llvm-lld in any case.
# For macOS:
# - the linker is ld64, either from XCode on macOS, or from cctools-ports when
#   cross-compiling. lld can be enabled manually, but as of writing, mach-o support
#   for lld is incomplete.
# For other OSes:
# - on local developer builds: lld is used if present. Otherwise gold is used if present
#   otherwise, BFD ld is used.
# - on release/official builds: whatever "ld" resolves to is used, except on Android x86/x86_64
#   where BFD ld is used. Usually, "ld" resolves to BFD ld, except with the Android NDK,
#   where it resolves to gold. lld is not used by default on Linux and Android because
#   it introduces layout changes that prevent elfhack from working. See e.g.
#   https://bugzilla.mozilla.org/show_bug.cgi?id=1563654#c2.
@depends(target)
def is_linker_option_enabled(target):
    if target.kernel not in ('WINNT', 'SunOS'):
        return True


option('--enable-gold',
       env='MOZ_FORCE_GOLD',
       help='Enable GNU Gold Linker when it is not already the default',
       when=is_linker_option_enabled)

imply_option('--enable-linker', 'gold', when='--enable-gold')

@depends(target, developer_options)
def enable_linker_default(target, developer_options):
    # x86-64 gold has bugs in how it lays out .note.* sections. See bug 1573820.
    # x86-32 gold has a bug when assembly files are built. See bug 1651699.
    # lld is faster, so prefer that for developer builds.
    if target.os == 'Android' and target.cpu in ('x86', 'x86_64'):
        return 'lld' if developer_options else 'bfd'


js_option('--enable-linker', nargs=1,
          help='Select the linker {bfd, gold, ld64, lld, lld-*}{|}',
          default=enable_linker_default,
          when=is_linker_option_enabled)


# No-op to enable depending on --enable-linker from default_elfhack in
# toolkit/moz.configure.
@depends('--enable-linker', when=is_linker_option_enabled)
def enable_linker(linker):
    return linker


@depends('--enable-linker', c_compiler, developer_options, '--enable-gold',
         extra_toolchain_flags, target, when=is_linker_option_enabled)
@checking('for linker', lambda x: x.KIND)
@imports('os')
@imports('shutil')
def select_linker(linker, c_compiler, developer_options, enable_gold,
                  toolchain_flags, target):

    if linker:
        linker = linker[0]
    else:
        linker = None

    def is_valid_linker(linker):
        if target.kernel == 'Darwin':
            valid_linkers = ('ld64', 'lld')
        else:
            valid_linkers = ('bfd', 'gold', 'lld')
        if linker in valid_linkers:
            return True
        if 'lld' in valid_linkers and linker.startswith('lld-'):
            return True
        return False

    if linker and not is_valid_linker(linker):
        # Check that we are trying to use a supported linker
        die('Unsupported linker ' + linker)

    # Check the kind of linker
    version_check = ['-Wl,--version']
    cmd_base = c_compiler.wrapper + [c_compiler.compiler] + c_compiler.flags

    def try_linker(linker):
        # Generate the compiler flag
        if linker == 'ld64':
            linker_flag = ['-fuse-ld=ld']
        elif linker:
            linker_flag = ["-fuse-ld=" + linker]
        else:
            linker_flag = []
        cmd = cmd_base + linker_flag + version_check
        if toolchain_flags:
            cmd += toolchain_flags

        # ld64 doesn't have anything to print out a version. It does print out
        # "ld64: For information on command line options please use 'man ld'."
        # but that would require doing two attempts, one with --version, that
        # would fail, and another with --help.
        # Instead, abuse its LD_PRINT_OPTIONS feature to detect a message
        # specific to it on stderr when it fails to process --version.
        env = dict(os.environ)
        env['LD_PRINT_OPTIONS'] = '1'
        # Some locales might not print out the strings we are looking for, so
        # ensure consistent output.
        env['LC_ALL'] = 'C'
        retcode, stdout, stderr = get_cmd_output(*cmd, env=env)
        if retcode == 1 and 'Logging ld64 options' in stderr:
            kind = 'ld64'

        elif retcode != 0:
            return None

        elif 'GNU ld' in stdout:
            # We are using the normal linker
            kind = 'bfd'

        elif 'GNU gold' in stdout:
            kind = 'gold'

        elif 'LLD' in stdout:
            kind = 'lld'

        else:
            kind = 'unknown'

        return namespace(
            KIND=kind,
            LINKER_FLAG=linker_flag,
        )

    result = try_linker(linker)
    if result is None:
        if linker:
            die("Could not use {} as linker".format(linker))
        die("Failed to find a linker")

    if (linker is None and enable_gold.origin == 'default' and
            developer_options and result.KIND in ('bfd', 'gold')):
        # try and use lld if available.
        tried = try_linker('lld')
        if result.KIND != 'gold' and (tried is None or tried.KIND != 'lld'):
            tried = try_linker('gold')
            if tried is None or tried.KIND != 'gold':
                tried = None
        if tried:
            result = tried

    # If an explicit linker was given, error out if what we found is different.
    if linker and not linker.startswith(result.KIND):
        die("Could not use {} as linker".format(linker))

    return result


set_config('LINKER_KIND', select_linker.KIND)


@depends_if(select_linker, macos_sdk)
def linker_ldflags(linker, macos_sdk):
    flags = list((linker and linker.LINKER_FLAG) or [])
    if macos_sdk:
        if linker and linker.KIND == 'ld64':
            flags.append('-Wl,-syslibroot,%s' % macos_sdk)
        else:
            flags.append('-Wl,--sysroot=%s' % macos_sdk)

    return flags


add_old_configure_assignment('LINKER_LDFLAGS', linker_ldflags)


# There's a wrinkle with MinGW: linker configuration is not enabled, so
# `select_linker` is never invoked.  Hard-code around it.
@depends(select_linker, target, c_compiler)
def gcc_use_gnu_ld(select_linker, target, c_compiler):
    if select_linker is not None:
        return select_linker.KIND in ('bfd', 'gold', 'lld')
    if target.kernel == 'WINNT' and c_compiler.type == 'clang':
        return True
    return None


# GCC_USE_GNU_LD=1 means the linker is command line compatible with GNU ld.
set_config('GCC_USE_GNU_LD', gcc_use_gnu_ld)
add_old_configure_assignment('GCC_USE_GNU_LD', gcc_use_gnu_ld)

# Assembler detection
# ==============================================================

js_option(env='AS', nargs=1, help='Path to the assembler')

@depends(target, c_compiler)
def as_info(target, c_compiler):
    if c_compiler.type == 'clang-cl':
        ml = {
            'x86': 'ml.exe',
            'x86_64': 'ml64.exe',
            'aarch64': 'armasm64.exe',
        }.get(target.cpu)
        return namespace(
            type='masm',
            names=(ml, )
        )
    # When building with anything but clang-cl, we just use the C compiler as the assembler.
    return namespace(
        type='gcc',
        names=(c_compiler.compiler, )
    )

# One would expect the assembler to be specified merely as a program.  But in
# cases where the assembler is passed down into js/, it can be specified in
# the same way as CC: a program + a list of argument flags.  We might as well
# permit the same behavior in general, even though it seems somewhat unusual.
# So we have to do the same sort of dance as we did above with
# `provided_compiler`.
provided_assembler = provided_program('AS')
assembler = check_prog('_AS', input=provided_assembler.program,
                       what='the assembler', progs=as_info.names,
                       paths=toolchain_search_path)

@depends(as_info, assembler, provided_assembler, c_compiler)
def as_with_flags(as_info, assembler, provided_assembler, c_compiler):
    if provided_assembler:
        return provided_assembler.wrapper + \
            [assembler] + \
            provided_assembler.flags

    if as_info.type == 'masm':
        return assembler

    assert as_info.type == 'gcc'

    # Need to add compiler wrappers and flags as appropriate.
    return c_compiler.wrapper + [assembler] + c_compiler.flags


add_old_configure_assignment('AS', as_with_flags)
add_old_configure_assignment('ac_cv_prog_AS', as_with_flags)


@depends(assembler, c_compiler, extra_toolchain_flags)
@imports('subprocess')
@imports(_from='os', _import='devnull')
def gnu_as(assembler, c_compiler, toolchain_flags):
    # clang uses a compatible GNU assembler.
    if c_compiler.type == 'clang':
        return True

    if c_compiler.type == 'gcc':
        cmd = [assembler] + c_compiler.flags
        if toolchain_flags:
            cmd += toolchain_flags
        cmd += ['-Wa,--version', '-c', '-o', devnull, '-x', 'assembler', '-']
        # We don't actually have to provide any input on stdin, `Popen.communicate` will
        # close the stdin pipe.
        # clang will error if it uses its integrated assembler for this target,
        # so handle failures gracefully.
        if 'GNU' in check_cmd_output(*cmd, stdin=subprocess.PIPE, onerror=lambda: ''):
            return True


set_config('GNU_AS', gnu_as)
add_old_configure_assignment('GNU_AS', gnu_as)


@depends(as_info, target)
def as_dash_c_flag(as_info, target):
    # armasm64 doesn't understand -c.
    if as_info.type == 'masm' and target.cpu == 'aarch64':
        return ''
    else:
        return '-c'


set_config('AS_DASH_C_FLAG', as_dash_c_flag)


@depends(as_info, target)
def as_outoption(as_info, target):
    # The uses of ASOUTOPTION depend on the spacing for -o/-Fo.
    if as_info.type == 'masm' and target.cpu != 'aarch64':
        return '-Fo'

    return '-o '


set_config('ASOUTOPTION', as_outoption)

# clang plugin handling
# ==============================================================

js_option('--enable-clang-plugin', env='ENABLE_CLANG_PLUGIN',
          help="Enable building with the Clang plugin (gecko specific static analyzers)")

add_old_configure_assignment('ENABLE_CLANG_PLUGIN',
                             depends_if('--enable-clang-plugin')(lambda _: True))

js_option('--enable-clang-plugin-alpha', env='ENABLE_CLANG_PLUGIN_ALPHA',
            help='Enable static analysis with clang-plugin alpha checks.')

@depends('--enable-clang-plugin', '--enable-clang-plugin-alpha')
def check_clang_plugin_alpha(enable_clang_plugin, enable_clang_plugin_alpha):
    if enable_clang_plugin_alpha:
        if enable_clang_plugin:
            return True
        die("Cannot enable clang-plugin alpha checkers without --enable-clang-plugin.")

add_old_configure_assignment('ENABLE_CLANG_PLUGIN_ALPHA', check_clang_plugin_alpha)
set_define('MOZ_CLANG_PLUGIN_ALPHA', check_clang_plugin_alpha)

js_option('--enable-mozsearch-plugin', env='ENABLE_MOZSEARCH_PLUGIN',
          help="Enable building with the mozsearch indexer plugin")

add_old_configure_assignment('ENABLE_MOZSEARCH_PLUGIN',
                             depends_if('--enable-mozsearch-plugin')(lambda _: True))

# Libstdc++ compatibility hacks
# ==============================================================
#
js_option('--enable-stdcxx-compat', env='MOZ_STDCXX_COMPAT',
          help='Enable compatibility with older libstdc++')


@template
def libstdcxx_version(var, compiler):
    @depends(compiler, when='--enable-stdcxx-compat')
    @checking(var, lambda v: v and "GLIBCXX_%s" % v.dotted)
    @imports(_from='mozbuild.configure.libstdcxx', _import='find_version')
    @imports(_from='__builtin__', _import='Exception')
    def version(compiler):
        try:
            result = find_version(
                compiler.wrapper + [compiler.compiler] + compiler.flags)
        except Exception:
            die("Couldn't determine libstdc++ version")
        if result:
            return namespace(
                dotted=result[0],
                encoded=str(result[1]),
            )

    set_config(var, version.encoded)
    return version


add_gcc_flag(
    '-D_GLIBCXX_USE_CXX11_ABI=0', cxx_compiler,
    when=libstdcxx_version(
        'MOZ_LIBSTDCXX_TARGET_VERSION', cxx_compiler))
add_gcc_flag(
    '-D_GLIBCXX_USE_CXX11_ABI=0', host_cxx_compiler,
    when=libstdcxx_version(
        'MOZ_LIBSTDCXX_HOST_VERSION', host_cxx_compiler))


# Support various fuzzing options
# ==============================================================
js_option('--enable-fuzzing', help='Enable fuzzing support')

@depends('--enable-fuzzing')
def enable_fuzzing(value):
    if value:
        return True

@depends(try_compile(body='__AFL_COMPILER;',
                     check_msg='for AFL compiler',
                     when='--enable-fuzzing'))
def enable_aflfuzzer(afl):
    if afl:
        return True

@depends(enable_fuzzing,
         enable_aflfuzzer,
         c_compiler,
         target)
def enable_libfuzzer(fuzzing, afl, c_compiler, target):
    if fuzzing and not afl and c_compiler.type == 'clang' and target.os != 'Android':
        return True

@depends(enable_fuzzing,
         enable_aflfuzzer,
         enable_libfuzzer)
def enable_fuzzing_interfaces(fuzzing, afl, libfuzzer):
    if fuzzing and (afl or libfuzzer):
        return True

set_config('FUZZING', enable_fuzzing)
set_define('FUZZING', enable_fuzzing)

set_config('LIBFUZZER', enable_libfuzzer)
set_define('LIBFUZZER', enable_libfuzzer)
add_old_configure_assignment('LIBFUZZER', enable_libfuzzer)

set_config('FUZZING_INTERFACES', enable_fuzzing_interfaces)
set_define('FUZZING_INTERFACES', enable_fuzzing_interfaces)
add_old_configure_assignment('FUZZING_INTERFACES', enable_fuzzing_interfaces)


@depends(c_compiler.try_compile(flags=['-fsanitize=fuzzer-no-link'],
         when=enable_fuzzing,
         check_msg='whether the C compiler supports -fsanitize=fuzzer-no-link'), tsan)
def libfuzzer_flags(value, tsan):
    if tsan:
        # With ThreadSanitizer, we should not use any libFuzzer instrumentation because
        # it is incompatible (e.g. there are races on global sanitizer coverage counters).
        # Instead we use an empty set of flags here but still build the fuzzing targets.
        # With this setup, we can still run files through these targets in TSan builds,
        # e.g. those obtained from regular fuzzing.
        # This code can be removed once libFuzzer has been made compatible with TSan.
        return namespace(no_link_flag_supported=False, use_flags=[])

    if value:
        no_link_flag_supported = True
        # recommended for (and only supported by) clang >= 6
        use_flags = ['-fsanitize=fuzzer-no-link']
    else:
        no_link_flag_supported = False
        use_flags = ['-fsanitize-coverage=trace-pc-guard,trace-cmp']

    return namespace(
        no_link_flag_supported=no_link_flag_supported,
        use_flags=use_flags,
    )

set_config('HAVE_LIBFUZZER_FLAG_FUZZER_NO_LINK', libfuzzer_flags.no_link_flag_supported)
set_config('LIBFUZZER_FLAGS', libfuzzer_flags.use_flags)
add_old_configure_assignment('LIBFUZZER_FLAGS', libfuzzer_flags.use_flags)

# Shared library building
# ==============================================================

# XXX: The use of makefile constructs in these variables is awful.
@depends(target, c_compiler)
def make_shared_library(target, compiler):
    if target.os == 'WINNT':
        if compiler.type == 'gcc':
            return namespace(
                mkshlib=['$(CXX)', '$(DSO_LDOPTS)', '-o', '$@'],
                mkcshlib=['$(CC)', '$(DSO_LDOPTS)', '-o', '$@'],
            )
        elif compiler.type == 'clang':
            return namespace(
                mkshlib=['$(CXX)', '$(DSO_LDOPTS)', '-Wl,-pdb,$(LINK_PDBFILE)', '-o', '$@'],
                mkcshlib=['$(CC)', '$(DSO_LDOPTS)', '-Wl,-pdb,$(LINK_PDBFILE)', '-o', '$@'],
            )
        else:
            linker = [
                '$(LINKER)',
                '-NOLOGO', '-DLL',
                '-OUT:$@',
                '-PDB:$(LINK_PDBFILE)',
                '$(DSO_LDOPTS)'
            ]
            return namespace(
                mkshlib=linker,
                mkcshlib=linker,
            )

    cc = ['$(CC)', '$(COMPUTED_C_LDFLAGS)']
    cxx = ['$(CXX)', '$(COMPUTED_CXX_LDFLAGS)']
    flags = ['$(PGO_CFLAGS)', '$(DSO_PIC_CFLAGS)', '$(DSO_LDOPTS)']
    output = ['-o', '$@']

    if target.kernel == 'Darwin':
        soname = []
    elif target.os == 'NetBSD':
        soname = ['-Wl,-soname,$(DSO_SONAME)']
    else:
        assert compiler.type in ('gcc', 'clang')

        soname = ['-Wl,-h,$(DSO_SONAME)']

    return namespace(
        mkshlib=cxx + flags + soname + output,
        mkcshlib=cc + flags + soname + output,
    )


set_config('MKSHLIB', make_shared_library.mkshlib)
set_config('MKCSHLIB', make_shared_library.mkcshlib)


@depends(c_compiler, toolchain_prefix, when=target_is_windows)
def rc_names(c_compiler, toolchain_prefix):
    if c_compiler.type in ('gcc', 'clang'):
        return tuple('%s%s' % (p, 'windres')
                     for p in ('',) + (toolchain_prefix or ()))
    return ('llvm-rc',)


check_prog('RC', rc_names, paths=toolchain_search_path, when=target_is_windows)


@depends(link, toolchain_prefix, c_compiler)
def ar_config(link, toolchain_prefix, c_compiler):
    if c_compiler.type == 'clang-cl' and link:
        # if LINKER is set, it's either for lld-link or link
        if 'lld-link' in link:
            return namespace(
                names=('llvm-lib',),
                flags=('-llvmlibthin', '-out:$@'),
            )
        else:
            return namespace(
                names=('lib',),
                flags=('-NOLOGO', '-OUT:$@'),
            )
    return namespace(
        names=tuple('%s%s' % (p, 'ar')
                   for p in (toolchain_prefix or ()) + ('',)),
        flags=('crs', '$@'),
    )


ar = check_prog('AR', ar_config.names, paths=toolchain_search_path)

add_old_configure_assignment('AR', ar)

set_config('AR_FLAGS', ar_config.flags)


js_option('--enable-cpp-rtti', help='Enable C++ RTTI')

add_old_configure_assignment('_MOZ_USE_RTTI', '1', when='--enable-cpp-rtti')