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-rw-r--r--project/boost/build.py34
-rw-r--r--project/boost/directory.py18
-rw-r--r--project/boost/download.py5
-rw-r--r--project/boost/toolchain.py455
4 files changed, 453 insertions, 59 deletions
diff --git a/project/boost/build.py b/project/boost/build.py
index a9fe8da..3a073f3 100644
--- a/project/boost/build.py
+++ b/project/boost/build.py
@@ -5,8 +5,8 @@
R'''Build Boost.
-This script builds the Boost libraries. It's main utility is setting the
-correct --stagedir parameter value to avoid name clashes.
+This script builds the Boost libraries. It main utility is setting the correct
+--stagedir parameter value to avoid name clashes.
Usage example:
@@ -46,6 +46,7 @@ import sys
import tempfile
from project.boost.directory import BoostDir
+from project.toolchain import ToolchainType
from project.boost.toolchain import Toolchain
from project.configuration import Configuration
from project.linkage import Linkage
@@ -60,14 +61,14 @@ DEFAULT_CONFIGURATIONS = (Configuration.DEBUG, Configuration.RELEASE,)
# binaries from a CI, etc. and run them everywhere):
DEFAULT_LINK = (Linkage.STATIC,)
DEFAULT_RUNTIME_LINK = Linkage.STATIC
-# Shut compilers up:
-COMMON_B2_ARGS = ['-d0']
+B2_QUIET = ['-d0']
+B2_VERBOSE = ['-d2', '--debug-configuration']
class BuildParameters:
def __init__(self, boost_dir, build_dir=None, platforms=None,
configurations=None, link=None, runtime_link=None,
- mingw=False, b2_args=None):
+ toolset=None, verbose=False, b2_args=None):
boost_dir = normalize_path(boost_dir)
if build_dir is not None:
@@ -76,10 +77,12 @@ class BuildParameters:
configurations = configurations or DEFAULT_CONFIGURATIONS
link = link or DEFAULT_LINK
runtime_link = runtime_link or DEFAULT_RUNTIME_LINK
+ toolset = toolset or ToolchainType.AUTO
+ verbosity = B2_VERBOSE if verbose else B2_QUIET
if b2_args:
- b2_args = COMMON_B2_ARGS + b2_args
+ b2_args = verbosity + b2_args
else:
- b2_args = COMMON_B2_ARGS
+ b2_args = verbosity
self.boost_dir = boost_dir
self.build_dir = build_dir
@@ -88,17 +91,20 @@ class BuildParameters:
self.configurations = configurations
self.link = link
self.runtime_link = runtime_link
- self.mingw = mingw
+ self.toolset = toolset
self.b2_args = b2_args
@staticmethod
def from_args(args):
return BuildParameters(**vars(args))
+ def get_bootstrap_args(self):
+ return self.toolset.get_bootstrap_args()
+
def enum_b2_args(self):
with self._create_build_dir() as build_dir:
for platform in self.platforms:
- with Toolchain.detect(platform, mingw=self.mingw) as toolchain:
+ with Toolchain.detect(self.toolset, platform) as toolchain:
for configuration in self.configurations:
for link, runtime_link in self._linkage_options():
yield self._build_params(build_dir, toolchain,
@@ -138,9 +144,9 @@ class BuildParameters:
params.append(self._stagedir(toolchain, configuration))
params.append('--layout=system')
params += toolchain.get_b2_args()
+ params.append(self._variant(configuration))
params.append(self._link(link))
params.append(self._runtime_link(runtime_link))
- params.append(self._variant(configuration))
params += self.b2_args
return params
@@ -204,8 +210,10 @@ def _parse_args(argv=None):
type=Linkage.parse, default=DEFAULT_RUNTIME_LINK,
help=f'how the libraries link to the runtime ({linkage_options})')
- parser.add_argument('--mingw', action='store_true',
- help='build using MinGW-w64')
+ toolset_options = '/'.join(map(str, ToolchainType.all()))
+ parser.add_argument('--toolset', metavar='TOOLSET',
+ type=ToolchainType.parse, default=ToolchainType.AUTO,
+ help=f'toolset to use ({toolset_options})')
parser.add_argument('--build', metavar='DIR', dest='build_dir',
type=normalize_path,
@@ -214,6 +222,8 @@ def _parse_args(argv=None):
type=normalize_path,
help='root Boost directory')
+ parser.add_argument('-v', '--verbose', action='store_true',
+ help='verbose b2 invocation (quiet by default)')
parser.add_argument('b2_args', metavar='B2_ARG',
nargs='*', default=[],
help='additional b2 arguments, to be passed verbatim')
diff --git a/project/boost/directory.py b/project/boost/directory.py
index 17448b6..9b35194 100644
--- a/project/boost/directory.py
+++ b/project/boost/directory.py
@@ -6,6 +6,7 @@
import logging
import os.path
+from project.boost.toolchain import BootstrapToolchain
from project.utils import cd, run
from project.os import on_windows
@@ -21,18 +22,19 @@ class BoostDir:
def build(self, params):
with self._go():
- self._bootstrap_if_required()
+ self._bootstrap_if_required(params)
self._b2(params)
- def _bootstrap_if_required(self):
+ def _bootstrap_if_required(self, params):
if os.path.isfile(self._b2_path()):
logging.info('Not going to bootstrap, b2 is already there')
return
- self.bootstrap()
+ self.bootstrap(params)
- def bootstrap(self):
+ def bootstrap(self, params):
with self._go():
- run(self._bootstrap_path())
+ toolchain = BootstrapToolchain.detect(params.toolset)
+ run([self._bootstrap_path()] + self._bootstrap_args(toolchain))
def _b2(self, params):
for b2_params in params.enum_b2_args():
@@ -50,6 +52,12 @@ class BoostDir:
return f'bootstrap{ext}'
@staticmethod
+ def _bootstrap_args(toolchain):
+ if on_windows():
+ return toolchain.get_bootstrap_bat_args()
+ return toolchain.get_bootstrap_sh_args()
+
+ @staticmethod
def _b2_path():
return os.path.join('.', BoostDir._b2_name())
diff --git a/project/boost/download.py b/project/boost/download.py
index c3451a8..ca113a6 100644
--- a/project/boost/download.py
+++ b/project/boost/download.py
@@ -5,8 +5,8 @@
R'''Download & bootstrap Boost.
-This script downloads and bootstraps a Boost distribution. It's main utility
-is that it's supposed to be cross-platform.
+This script downloads and unpacks a Boost distribution archive. Its main
+utility is that it's supposed to be cross-platform.
Usage examples:
@@ -97,7 +97,6 @@ def download(params):
with _download_if_necessary(params.version, params.storage) as path:
archive = Archive(params.version, path)
boost_dir = archive.unpack(params.unpack_dir)
- boost_dir.bootstrap()
params.rename_if_necessary(boost_dir)
diff --git a/project/boost/toolchain.py b/project/boost/toolchain.py
index a77c073..cce06a4 100644
--- a/project/boost/toolchain.py
+++ b/project/boost/toolchain.py
@@ -3,78 +3,455 @@
# For details, see https://github.com/egor-tensin/cmake-common.
# Distributed under the MIT License.
-R'''Compiler detection.
-
-It is assumed that Boost.Build is good enough to detect both GCC on Linux and
-MSVC on Windows. From that point on, it's just a matter of setting the correct
-address-model= value.
-
-But I also frequently use MinGW-w64, and the most convinient way to use it that
-I know is making a "user config" and passing it to b2 using the --user-config
-parameter.
-'''
+# Hate speech
+# -----------
+#
+# Is there a person who doesn't hate Boost.Build? I'm not sure, I'm definitely
+# _not_ one of these people. Maybe it's the lack of adoption (meaning that
+# learning it is useless outside of Boost), maybe it's the incomprehensible
+# syntax. Maybe it's the absolutely insane compiler-specific configuration
+# files (tools/build/src/tools/*.jam), which are impossible to figure out.
+# Maybe it's the fact that the implementation switched from C to C++ while some
+# half-baked Python implementation has been there since at least 2015 (see the
+# marvelous memo "Status: mostly ported." at the top of tools/build/src/build_system.py).
+#
+# What I hate the most though is how its various subtle, implicit and invisible
+# decision-making heuristics changed thoughout the release history of Boost.
+# You have a config and a compiler that will happily build version 1.65.0?
+# Great! Want to use the same config and the same compiler to build version
+# 1.72.0? Well, too fucking bad, it doesn't work anymore. This I really do
+# hate the most.
+#
+# Three kinds of toolsets
+# -----------------------
+#
+# b2 accepts the toolset= parameter. What about building b2 itself though?
+# Well, this is what the bootstrap.{sh,bat} scripts do. They also accept a
+# toolset argument, but it is _completely_ different to that of b2. That's
+# sort of OK, since e.g. cross-compiling b2 is something we rarely want to do
+# (and hence there must typically be a native toolset available).
+#
+# bootstrap.sh and bootstrap.bat are completely different (of course!), and
+# accept different arguments for their toolset parameters.
+#
+# Config file insanity
+# --------------------
+#
+# Say, we're building Boost on Windows using the GCC from a MinGW-w64
+# distribution. We can pass toolset=gcc and all the required flags on the
+# command line no problem. What if we want to make a user configuration file
+# so that 1) the command line is less polluted, and 2) it can possibly be
+# shared? Well, if we put
+#
+# using gcc : : : <name>value... ;
+#
+# there, Boost 1.65.0 will happily build everything, while Boost 1.72.0 will
+# complain about "duplicate initialization of gcc". This is because when we
+# ran `bootstrap.bat gcc` earlier, it wrote `using gcc ;` in project-config.jam.
+# And while Boost 1.65.0 detects that toolset=gcc means we're going to use the
+# MinGW GCC, and magically turns toolset=gcc to toolset=gcc-mingw, Boost 1.72.0
+# does no such thing, and chokes on the "duplicate" GCC declaration.
+#
+# We also cannot put
+#
+# using gcc : custom : : <options> ;
+#
+# without the executable path, since Boost insists that `g++ -dumpversion` must
+# equal to "custom" (which makes total sense, lol). So we have to force it,
+# and do provide the path.
+#
+# Windows & Clang
+# ---------------
+#
+# Building Boost using Clang on Windows is a sad story. As of 2020, there're
+# three main ways to install the native Clang toolchain on Windows:
+#
+# * download the installer from llvm.org (`choco install llvm` does this)
+# a.k.a. the upstream,
+# * install it as part of a MSYS2 installation (`pacman -S mingw-w64-x86_64-clang`),
+# * install as part of a Visual Studio installation.
+#
+# Using the latter method, you can switch a project to use the LLVM toolset
+# using Visual Studio, but that's stupid. The former two, on the other hand,
+# give us the the required clang/clang++/clang-cl executables, so everything
+# seems to be fine.
+#
+# Except it's not fine. Let's start with the fact that prior to 1.66.0,
+# toolset=clang is completely broken on Windows. It's just an alias for
+# clang-linux, and it's hardcoded to require the ar & ranlib executables to
+# create static libraries. Which is fine on Linux, since, and I'm quoting the
+# source, "ar is always available". But it's not fine on Windows, since
+# ar/ranlib are not, in fact, available there by default. Sure, you can
+# install some kind of MinGW toolchain, and it might even work, but what the
+# hell, honestly?
+#
+# Luckily, both the upstream distribution and the MSYS2 mingw-w64-x86_64-llvm
+# package come with the llvm-ar and llvm-ranlib utilities. So we can put
+# something like this in the config:
+#
+# using clang : custom : clang++.exe : <archiver>llvm-ar <ranlib>llvm-ranlib.exe ;
+#
+# and later call
+#
+# b2 toolset=clang-custom --user-config=path/to/config.jam ...
+#
+# But, as I mentioned, prior to 1.66.0, toolset=clang is _hardcoded_ to use ar
+# & ranlib, these exact utility names. So either get them as part of some
+# MinGW distribution or build Boost using another toolset.
+#
+# Now, it's all fine, but building stuff on Windows adds another thing into the
+# equation: debug runtimes. When you build Boost using MSVC, for example, it
+# picks one of the appropriate /MT[d] or /MD[d] flags to build the Boost
+# libraries with. Emulating these flags with toolset=clang is complicated and
+# inconvenient. Luckily, there's the clang-cl.exe executable, which aims to
+# provide command line interface compatible with that of cl.exe.
+#
+# Boost.Build even supports toolset=clang-win, which should use clang-cl.exe.
+# But alas, it's completely broken prior to 1.69.0. It just doesn't work at
+# all. So, if you want to build w/ clang-cl.exe, either use Boost 1.69.0 or
+# later, or build using another toolset.
+#
+# Cygwin & Clang
+# --------------
+#
+# Now, a few words about Clang on Cygwin. When building 1.65.0, I encountered
+# the following error:
+#
+# /usr/include/w32api/synchapi.h:127:26: error: conflicting types for 'Sleep'
+# WINBASEAPI VOID WINAPI Sleep (DWORD dwMilliseconds);
+# ^
+# ./boost/smart_ptr/detail/yield_k.hpp:64:29: note: previous declaration is here
+# extern "C" void __stdcall Sleep( unsigned long ms );
+# ^
+#
+# GCC doesn't emit an error here because /usr/include is in a pre-configured
+# "system" include directories list, and the declaration there take precedence,
+# I guess? The root of the problem BTW is that sizeof(unsigned long) is
+#
+# * 4 for MSVC and MinGW-born GCCs,
+# * 8 for Clang (and, strangely, Cygwin GCC; why don't we get runtime
+# errors?).
+#
+# The fix is to add `define=BOOST_USE_WINDOWS_H`. I don't even know what's the
+# point of not having it as a default.
import abc
from contextlib import contextmanager
import logging
+import os.path
+import shutil
import project.mingw
+import project.os
+from project.toolchain import ToolchainType
from project.utils import temp_file
+class BootstrapToolchain(abc.ABC):
+ @abc.abstractmethod
+ def get_bootstrap_bat_args(self):
+ pass
+
+ @abc.abstractmethod
+ def get_bootstrap_sh_args(self):
+ pass
+
+ @staticmethod
+ def detect(hint):
+ if hint is ToolchainType.AUTO:
+ return BootstrapAuto()
+ if hint is ToolchainType.MSVC:
+ return BootstrapMSVC()
+ if hint is ToolchainType.GCC:
+ return BootstrapGCC()
+ if hint is ToolchainType.MINGW:
+ return BootstrapMinGW()
+ if hint is ToolchainType.CLANG:
+ return BootstrapClang()
+ if hint is ToolchainType.CLANG_CL:
+ return BootstrapClangCL()
+ raise NotImplementedError(f'unrecognized toolset: {hint}')
+
+
+class BootstrapAuto(BootstrapToolchain):
+ # Let Boost.Build do the detection. Most commonly it means GCC on
+ # Linux-likes and MSVC on Windows.
+
+ def get_bootstrap_bat_args(self):
+ return []
+
+ def get_bootstrap_sh_args(self):
+ return []
+
+
+class BootstrapMSVC(BootstrapAuto):
+ # bootstrap.bat picks up MSVC by default.
+ pass
+
+
+class BootstrapGCC(BootstrapToolchain):
+ def get_bootstrap_bat_args(self):
+ return ['gcc']
+
+ def get_bootstrap_sh_args(self):
+ return ['--with-toolset=gcc']
+
+
+def _gcc_or_auto():
+ if shutil.which('gcc') is not None:
+ return ['gcc']
+ return []
+
+
+class BootstrapMinGW(BootstrapToolchain):
+ def get_bootstrap_bat_args(self):
+ # On Windows, prefer GCC if it's available.
+ return _gcc_or_auto()
+
+ def get_bootstrap_sh_args(self):
+ return []
+
+
+class BootstrapClang(BootstrapToolchain):
+ def get_bootstrap_bat_args(self):
+ # As of 1.74.0, bootstrap.bat isn't really aware of Clang, so try GCC,
+ # then auto-detect.
+ return _gcc_or_auto()
+
+ def get_bootstrap_sh_args(self):
+ # bootstrap.sh, on the other hand, is very much aware of Clang, and
+ # it can build b2 using this compiler.
+ return ['--with-toolset=clang']
+
+
+class BootstrapClangCL(BootstrapClang):
+ # There's no point in building b2 using clang-cl; clang though, presumably
+ # installed alongside clang-cl, should still be used if possible.
+ pass
+
+
class Toolchain(abc.ABC):
def __init__(self, platform):
self.platform = platform
- @abc.abstractmethod
def get_b2_args(self):
- pass
+ return [
+ # Always pass the address-model explicitly.
+ f'address-model={self.platform.get_address_model()}'
+ ]
@staticmethod
@contextmanager
- def detect(platform, mingw=False):
- if mingw:
+ def detect(hint, platform):
+ if hint is ToolchainType.AUTO:
+ yield Auto(platform)
+ elif hint is ToolchainType.MSVC:
+ yield MSVC(platform)
+ elif hint is ToolchainType.GCC:
+ with GCC.setup(platform) as toolchain:
+ yield toolchain
+ elif hint is ToolchainType.MINGW:
with MinGW.setup(platform) as toolchain:
yield toolchain
+ elif hint is ToolchainType.CLANG:
+ with Clang.setup(platform) as toolchain:
+ yield toolchain
+ elif hint is ToolchainType.CLANG_CL:
+ yield ClangCL(platform)
else:
- yield Native(platform)
+ raise NotImplementedError(f'unrecognized toolset: {hint}')
- @staticmethod
- def _format_user_config(tag, compiler, **kwargs):
- features = (f'<{k}>{v}' for k, v in kwargs.items())
- features = ' '.join(features)
- return f'using gcc : {tag} : {compiler} : {features} ;'
+class Auto(Toolchain):
+ # Let Boost.Build do the detection. Most commonly it means GCC on
+ # Linux-likes and MSVC on Windows.
+ pass
-class Native(Toolchain):
+
+class MSVC(Auto):
def get_b2_args(self):
- return [f'address-model={self.platform.get_address_model()}']
+ return super().get_b2_args() + [
+ 'toolset=msvc',
+ ]
+
+def _full_exe_name(exe):
+ if project.os.on_linux():
+ # There's no PATHEXT on Linux.
+ return exe
+ # b2 on Windows/Cygwin doesn't like it when the executable name doesn't
+ # include the extension.
+ dir_path = os.path.dirname(exe) or None
+ path = shutil.which(exe, path=dir_path)
+ if not path:
+ raise RuntimeError(f"executable '{exe}' could not be found")
+ if project.os.on_cygwin():
+ # On Cygwin, shutil.which('gcc') == '/usr/bin/gcc' and shutil.which('gcc.exe')
+ # == '/usr/bin/gcc.exe'; we want the latter version. shutil.which('clang++')
+ # == '/usr/bin/clang++' is fine though, since it _is_ the complete path
+ # (clang++ is a symlink).
+ if os.path.exists(path) and os.path.exists(path + '.exe'):
+ path += '.exe'
+ if dir_path:
+ # If it was found in a specific directory, include the directory in the
+ # result. shutil.which returns the executable name prefixed with the
+ # path argument.
+ return path
+ # If it was found in PATH, just return the basename (which includes the
+ # extension).
+ return os.path.basename(path)
-class MinGW(Toolchain):
- TAG = 'custom'
- def __init__(self, platform, config_path):
+class BoostBuildToolset:
+ CUSTOM = 'custom'
+
+ def __init__(self, compiler, path, options):
+ if not compiler:
+ raise RuntimeError('compiler type is required (like gcc, clang, etc.)')
+ self.compiler = compiler
+ self.version = BoostBuildToolset.CUSTOM
+ path = path or ''
+ path = path and _full_exe_name(path)
+ self.path = path
+ options = options or []
+ self.options = options
+
+ @property
+ def toolset_id(self):
+ if self.version:
+ return f'{self.compiler}-{self.version}'
+ return self.compiler
+
+ @property
+ def b2_arg(self):
+ return f'toolset={self.toolset_id}'
+
+ def _format_using_options(self):
+ return ''.join(f'\n <{name}>{val}' for name, val in self.options)
+
+ def format_using(self):
+ version = self.version and f'{self.version} '
+ path = self.path and f'{self.path} '
+ return f'''using {self.compiler} : {version}: {path}:{self._format_using_options()}
+;'''
+
+
+class ConfigFile(Toolchain):
+ def __init__(self, platform, config_path, toolset):
super().__init__(platform)
self.config_path = config_path
-
- def get_b2_args(self):
- return [f'--user-config={self.config_path}', f'toolset=gcc-{MinGW.TAG}']
+ self.toolset = toolset
@staticmethod
- def _format_mingw_user_config(platform):
- compiler = project.mingw.get_gxx(platform)
- features = {
- 'target-os': 'windows',
- 'address-model': platform.get_address_model(),
- }
- return Toolchain._format_user_config(MinGW.TAG, compiler, **features)
+ @abc.abstractmethod
+ def get_toolset(platform):
+ pass
@staticmethod
+ @abc.abstractmethod
+ def format_config(toolset):
+ pass
+
+ @classmethod
@contextmanager
- def setup(platform):
- config = MinGW._format_mingw_user_config(platform)
+ def setup(cls, platform):
+ toolset = cls.get_toolset(platform)
+ config = cls.format_config(toolset)
logging.info('Using user config:\n%s', config)
- tmp = temp_file(config, mode='w', prefix='mingw_w64_', suffix='.jam')
+ tmp = temp_file(config, mode='w', prefix='user_config_', suffix='.jam')
with tmp as path:
- yield MinGW(platform, path)
+ yield cls(platform, path, toolset)
+
+ def get_b2_args(self):
+ # All the required options and the toolset definition should be in the
+ # user configuration file.
+ return super().get_b2_args() + [
+ f'--user-config={self.config_path}',
+ self.toolset.b2_arg,
+ ]
+
+
+class GCC(ConfigFile):
+ # Force GCC. We don't care whether it's a native Linux GCC or a
+ # MinGW-flavoured GCC on Windows.
+ COMPILER = 'gcc'
+
+ @staticmethod
+ def get_options():
+ return [
+ # TODO: this is a petty attempt to get rid of build warnings in
+ # older Boost versions. Revise and expand this list or remove it?
+ # warning: 'template<class> class std::auto_ptr' is deprecated
+ ('cxxflags', '-Wno-deprecated-declarations'),
+ # warning: unnecessary parentheses in declaration of 'assert_arg'
+ ('cxxflags', '-Wno-parentheses'),
+ ]
+
+ @staticmethod
+ def get_toolset(platform):
+ return BoostBuildToolset(GCC.COMPILER, 'g++', GCC.get_options())
+
+ @staticmethod
+ def format_config(toolset):
+ return toolset.format_using()
+
+
+class MinGW(GCC):
+ # It's important that Boost.Build is actually smart enough to detect the
+ # GCC prefix (like "x86_64-w64-mingw32" and prepend it to other tools like
+ # "ar").
+
+ @staticmethod
+ def get_toolset(platform):
+ path = project.mingw.get_gxx(platform)
+ return BoostBuildToolset(MinGW.COMPILER, path, MinGW.get_options())
+
+
+class Clang(ConfigFile):
+ COMPILER = 'clang'
+
+ @staticmethod
+ def get_toolset(platform):
+ options = [
+ ('cxxflags', '-DBOOST_USE_WINDOWS_H'),
+ # TODO: this is a petty attempt to get rid of build warnings in
+ # older Boost versions. Revise and expand this list or remove it?
+ # warning: unused typedef 'boost_concept_check464' [-Wunused-local-typedef]
+ ('cxxflags', '-Wno-unused-local-typedef'),
+ # error: constant expression evaluates to -105 which cannot be narrowed to type 'boost::re_detail::cpp_regex_traits_implementation<char>::char_class_type' (aka 'unsigned int')
+ ('cxxflags', '-Wno-c++11-narrowing'),
+ ] + GCC.get_options()
+ if project.os.on_windows():
+ # Prefer LLVM binutils:
+ if shutil.which('llvm-ar') is not None:
+ options.append(('archiver', 'llvm-ar'))
+ if shutil.which('llvm-ranlib') is not None:
+ options.append(('ranlib', 'llvm-ranlib'))
+ return BoostBuildToolset(Clang.COMPILER, 'clang++', options)
+
+ @staticmethod
+ def format_config(toolset):
+ # To make clang.exe/clang++.exe work on Windows, some tweaks are
+ # required. I borrowed them from CMake's Windows-Clang.cmake [1].
+ # Adding them globally to Boost.Build options is described in [2].
+ #
+ # [1]: https://github.com/Kitware/CMake/blob/v3.18.4/Modules/Platform/Windows-Clang.cmake
+ # [2]: https://stackoverflow.com/questions/2715106/how-to-create-a-new-variant-in-bjam
+ return f'''project : requirements
+ <target-os>windows:<define>_MT
+ <target-os>windows,<variant>debug:<define>_DEBUG
+ <target-os>windows,<runtime-link>static,<variant>debug:<cxxflags>"-Xclang -flto-visibility-public-std -Xclang --dependent-lib=libcmtd"
+ <target-os>windows,<runtime-link>static,<variant>release:<cxxflags>"-Xclang -flto-visibility-public-std -Xclang --dependent-lib=libcmt"
+ <target-os>windows,<runtime-link>shared,<variant>debug:<cxxflags>"-D_DLL -Xclang --dependent-lib=msvcrtd"
+ <target-os>windows,<runtime-link>shared,<variant>release:<cxxflags>"-D_DLL -Xclang --dependent-lib=msvcrt"
+;
+{toolset.format_using()}
+'''
+
+
+class ClangCL(Toolchain):
+ def get_b2_args(self):
+ return super().get_b2_args() + [
+ f'toolset=clang-win',
+ 'define=BOOST_USE_WINDOWS_H',
+ ]