Download MSVC compiler/linker & Windows SDK without installing full Visual Studio

!README.md

This downloads standalone MSVC compiler, linker & other tools, also headers/libraries from Windows SDK into portable folder, without installing Visual Studio. Has bare minimum components - no UWP/Store/WindowsRT stuff, just files & tools for native desktop app development.

Run py.exe portable-msvc.py and it will download output into msvc folder. By default it will download latest available MSVC & Windows SDK - currently v14.40.33807 and v10.0.26100.0.

You can list available versions with py.exe portable-msvc.py --show-versions and then pass versions you want with --msvc-version and --sdk-version arguments.

To use cl.exe/link.exe first run setup_TARGET.bat - after that PATH/INCLUDE/LIB env variables will be updated to use all the tools as usual. You can also use clang-cl.exe with these includes & libraries.

To use clang-cl.exe without running setup.bat, pass extra /winsysroot msvc argument (msvc is folder name where output is stored).

portable-msvc.py

#!/usr/bin/env python3

import io
import os
import sys
import stat
import json
import shutil
import hashlib
import zipfile
import tempfile
import argparse
import subprocess
import urllib.error
import urllib.request
from pathlib import Path

OUTPUT = Path("msvc")         # output folder
DOWNLOADS = Path("downloads") # temporary download files

# NOTE: not all host & target architecture combinations are supported

DEFAULT_HOST = "x64"
ALL_HOSTS    = "x64 x86 arm64".split()

DEFAULT_TARGET = "x64"
ALL_TARGETS    = "x64 x86 arm arm64".split()

MANIFEST_URL = "https://aka.ms/vs/17/release/channel"
MANIFEST_PREVIEW_URL = "https://aka.ms/vs/17/pre/channel"

ssl_context = None

def download(url):
  with urllib.request.urlopen(url, context=ssl_context) as res:
    return res.read()

total_download = 0

def download_progress(url, check, name, filename):
  fpath = DOWNLOADS / filename
  if fpath.exists():
    data = fpath.read_bytes()
    if hashlib.sha256(data).hexdigest() == check.lower():
      print(f"\r{name} ... OK")
      return data

  global total_download
  with fpath.open("wb") as f:
    data = io.BytesIO()
    with urllib.request.urlopen(url, context=ssl_context) as res:
      total = int(res.headers["Content-Length"])
      size = 0
      while True:
        block = res.read(1<<20)
        if not block:
          break
        f.write(block)
        data.write(block)
        size += len(block)
        perc = size * 100 // total
        print(f"\r{name} ... {perc}%", end="")
    print()
    data = data.getvalue()
    digest = hashlib.sha256(data).hexdigest()
    if check.lower() != digest:
      exit(f"Hash mismatch for f{pkg}")
    total_download += len(data)
    return data

# super crappy msi format parser just to find required .cab files
def get_msi_cabs(msi):
  index = 0
  while True:
    index = msi.find(b".cab", index+4)
    if index < 0:
      return
    yield msi[index-32:index+4].decode("ascii")

def first(items, cond):
  return next((item for item in items if cond(item)), None)
  

### parse command-line arguments

ap = argparse.ArgumentParser()
ap.add_argument("--show-versions", action="store_true", help="Show available MSVC and Windows SDK versions")
ap.add_argument("--accept-license", action="store_true", help="Automatically accept license")
ap.add_argument("--msvc-version", help="Get specific MSVC version")
ap.add_argument("--sdk-version", help="Get specific Windows SDK version")
ap.add_argument("--preview", action="store_true", help="Use preview channel for Preview versions")
ap.add_argument("--target", default=DEFAULT_TARGET, help=f"Target architectures, comma separated ({','.join(ALL_TARGETS)})")
ap.add_argument("--host", default=DEFAULT_HOST, help=f"Host architecture", choices=ALL_HOSTS)
args = ap.parse_args()

host = args.host
targets = args.target.split(',')
for target in targets:
  if target not in ALL_TARGETS:
    exit(f"Unknown {target} target architecture!")


### get main manifest

URL = MANIFEST_PREVIEW_URL if args.preview else MANIFEST_URL

try:
  manifest = json.loads(download(URL))
except urllib.error.URLError as err:
  import ssl
  if isinstance(err.args[0], ssl.SSLCertVerificationError):
    # for more info about Python & issues with Windows certificates see https://stackoverflow.com/a/52074591
    print("ERROR: ssl certificate verification error")
    try:
      import certifi
    except ModuleNotFoundError:
      print("ERROR: please install 'certifi' package to use Mozilla certificates")
      print("ERROR: or update your Windows certs, see instructions here: https://woshub.com/updating-trusted-root-certificates-in-windows-10/#h2_3")
      exit()
    print("NOTE: retrying with certifi certificates")
    ssl_context = ssl.create_default_context(cafile=certifi.where())
    manifest = json.loads(download(URL))
  else:
    raise

### download VS manifest

ITEM_NAME = "Microsoft.VisualStudio.Manifests.VisualStudioPreview" if args.preview else "Microsoft.VisualStudio.Manifests.VisualStudio"

vs = first(manifest["channelItems"], lambda x: x["id"] == ITEM_NAME)
payload = vs["payloads"][0]["url"]

vsmanifest = json.loads(download(payload))


### find MSVC & WinSDK versions

packages = {}
for p in vsmanifest["packages"]:
  packages.setdefault(p["id"].lower(), []).append(p)

msvc = {}
sdk = {}

for pid,p in packages.items():
  if pid.startswith("Microsoft.VisualStudio.Component.VC.".lower()) and pid.endswith(".x86.x64".lower()):
    pver = ".".join(pid.split(".")[4:6])
    if pver[0].isnumeric():
      msvc[pver] = pid
  elif pid.startswith("Microsoft.VisualStudio.Component.Windows10SDK.".lower()) or \
       pid.startswith("Microsoft.VisualStudio.Component.Windows11SDK.".lower()):
    pver = pid.split(".")[-1]
    if pver.isnumeric():
      sdk[pver] = pid

if args.show_versions:
  print("MSVC versions:", " ".join(sorted(msvc.keys())))
  print("Windows SDK versions:", " ".join(sorted(sdk.keys())))
  exit(0)

msvc_ver = args.msvc_version or max(sorted(msvc.keys()))
sdk_ver = args.sdk_version or max(sorted(sdk.keys()))

if msvc_ver in msvc:
  msvc_pid = msvc[msvc_ver]
  msvc_ver = ".".join(msvc_pid.split(".")[4:-2])
else:
  exit(f"Unknown MSVC version: f{args.msvc_version}")

if sdk_ver in sdk:
  sdk_pid = sdk[sdk_ver]
else:
  exit(f"Unknown Windows SDK version: f{args.sdk_version}")

print(f"Downloading MSVC v{msvc_ver} and Windows SDK v{sdk_ver}")


### agree to license

tools = first(manifest["channelItems"], lambda x: x["id"] == "Microsoft.VisualStudio.Product.BuildTools")
resource = first(tools["localizedResources"], lambda x: x["language"] == "en-us")
license = resource["license"]

if not args.accept_license:
  accept = input(f"Do you accept Visual Studio license at {license} [Y/N] ? ")
  if not accept or accept[0].lower() != "y":
    exit(0)

OUTPUT.mkdir(exist_ok=True)
DOWNLOADS.mkdir(exist_ok=True)


### download MSVC

msvc_packages = [
  f"microsoft.visualcpp.dia.sdk",
  f"microsoft.vc.{msvc_ver}.crt.headers.base",
  f"microsoft.vc.{msvc_ver}.crt.source.base",
  f"microsoft.vc.{msvc_ver}.asan.headers.base",
  f"microsoft.vc.{msvc_ver}.premium.tools.{host}.base.base",
  f"microsoft.vc.{msvc_ver}.pgo.headers.base",
]

for target in targets:
  msvc_packages += [
    f"microsoft.vc.{msvc_ver}.tools.host{host}.target{target}.base",
    f"microsoft.vc.{msvc_ver}.tools.host{host}.target{target}.res.base",
    f"microsoft.vc.{msvc_ver}.crt.{target}.desktop.base",
    f"microsoft.vc.{msvc_ver}.crt.{target}.store.base",
    f"microsoft.vc.{msvc_ver}.crt.redist.{target}.base",
    f"microsoft.vc.{msvc_ver}.premium.tools.host{host}.target{target}.base",
    f"microsoft.vc.{msvc_ver}.pgo.{target}.base",
  ]
  if target in ["x86", "x64"]:
    msvc_packages += [
      f"microsoft.vc.{msvc_ver}.asan.{target}.base",
    ]

for pkg in msvc_packages:
  if pkg not in packages:
    continue
  p = first(packages[pkg], lambda p: p.get("language") in (None, "en-US"))
  for payload in p["payloads"]:
    filename = payload["fileName"]
    download_progress(payload["url"], payload["sha256"], pkg, filename)
    with zipfile.ZipFile(DOWNLOADS / filename) as z:
      for name in z.namelist():
        if name.startswith("Contents/"):
          out = OUTPUT / Path(name).relative_to("Contents")
          out.parent.mkdir(parents=True, exist_ok=True)
          out.write_bytes(z.read(name))


### download Windows SDK

sdk_packages = [
  f"Windows SDK for Windows Store Apps Tools-x86_en-us.msi",
  f"Windows SDK for Windows Store Apps Headers-x86_en-us.msi",
  f"Windows SDK for Windows Store Apps Headers OnecoreUap-x86_en-us.msi",
  f"Windows SDK for Windows Store Apps Libs-x86_en-us.msi",
  f"Windows SDK OnecoreUap Headers x86-x86_en-us.msi",
  f"Windows SDK Desktop Headers x86-x86_en-us.msi",
  f"Universal CRT Headers Libraries and Sources-x86_en-us.msi",
]

for target in targets:
  sdk_packages += [
    f"Windows SDK Desktop Libs {target}-x86_en-us.msi",
  ]

with tempfile.TemporaryDirectory(dir=DOWNLOADS) as d:
  dst = Path(d)

  sdk_pkg = packages[sdk_pid][0]
  sdk_pkg = packages[first(sdk_pkg["dependencies"], lambda x: True).lower()][0]

  msi = []
  cabs = []

  # download msi files
  for pkg in sdk_packages:
    payload = first(sdk_pkg["payloads"], lambda p: p["fileName"] == f"Installers\\{pkg}")
    if payload is None:
      continue
    msi.append(DOWNLOADS / pkg)
    data = download_progress(payload["url"], payload["sha256"], pkg, pkg)
    cabs += list(get_msi_cabs(data))

  # download .cab files
  for pkg in cabs:
    payload = first(sdk_pkg["payloads"], lambda p: p["fileName"] == f"Installers\\{pkg}")
    download_progress(payload["url"], payload["sha256"], pkg, pkg)

  print("Unpacking msi files...")

  # run msi installers
  for m in msi:
    subprocess.check_call(["msiexec.exe", "/a", m, "/quiet", "/qn", f"TARGETDIR={OUTPUT.resolve()}"])
    (OUTPUT / m.name).unlink()


### versions

msvcv = list((OUTPUT / "VC/Tools/MSVC").glob("*"))[0].name
sdkv = list((OUTPUT / "Windows Kits/10/bin").glob("*"))[0].name


# place debug CRT runtime files into MSVC bin filder (not what real Visual Studio installer does... but is reasonable)

redist = OUTPUT / "VC/Redist"

if redist.exists():
  src = redist / "MSVC" / msvcv / "debug_nonredist"
  for target in targets:
    for f in (src / target).glob("**/*.dll"):
      dst = OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{host}" / target
      f.replace(dst / f.name)

  shutil.rmtree(redist)


# move msdia140.dll file into MSVC folder

msdia140dll = {
  "x86": "msdia140.dll",
  "x64": "amd64/msdia140.dll",
  "arm": "arm/msdia140.dll",
  "arm64": "arm64/msdia140.dll",
}

dst = OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{host}"
src = OUTPUT / "DIA%20SDK/bin" / msdia140dll[host]
for target in targets:
  shutil.copyfile(src, dst / target / src.name)

shutil.rmtree(OUTPUT / "DIA%20SDK")


### cleanup

shutil.rmtree(OUTPUT / "Common7", ignore_errors=True)
shutil.rmtree(OUTPUT / "VC/Tools/MSVC" / msvcv / "Auxiliary")
for target in targets:
  for f in [f"store", "uwp", "enclave", "onecore"]:
    shutil.rmtree(OUTPUT / "VC/Tools/MSVC" / msvcv / "lib" / target / f, ignore_errors=True)
  shutil.rmtree(OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{host}" / target / "onecore", ignore_errors=True)
for f in ["Catalogs", "DesignTime", f"bin/{sdkv}/chpe", f"Lib/{sdkv}/ucrt_enclave"]:
  shutil.rmtree(OUTPUT / "Windows Kits/10" / f, ignore_errors=True)
for arch in ["x86", "x64", "arm", "arm64"]:
  if arch not in targets:
    shutil.rmtree(OUTPUT / "Windows Kits/10/Lib" / sdkv / "ucrt" / arch, ignore_errors=True)
    shutil.rmtree(OUTPUT / "Windows Kits/10/Lib" / sdkv / "um" / arch, ignore_errors=True)
  if arch != host:
    shutil.rmtree(OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{arch}", ignore_errors=True)
    shutil.rmtree(OUTPUT / "Windows Kits/10/bin" / sdkv / arch, ignore_errors=True)

# executable that is collecting & sending telemetry every time cl/link runs
for target in targets:
  (OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{host}/{target}/vctip.exe").unlink(missing_ok=True)


### setup.bat

for target in targets:

  SETUP = f"""@echo off

set ROOT=%~dp0

set MSVC_VERSION={msvcv}
set MSVC_HOST=Host{host}
set MSVC_ARCH={target}
set SDK_VERSION={sdkv}
set SDK_ARCH={target}

set MSVC_ROOT=%ROOT%VC\\Tools\\MSVC\\%MSVC_VERSION%
set SDK_INCLUDE=%ROOT%Windows Kits\\10\\Include\\%SDK_VERSION%
set SDK_LIBS=%ROOT%Windows Kits\\10\\Lib\\%SDK_VERSION%

set VCToolsInstallDir=%MSVC_ROOT%\\
set PATH=%MSVC_ROOT%\\bin\\%MSVC_HOST%\\%MSVC_ARCH%;%ROOT%Windows Kits\\10\\bin\\%SDK_VERSION%\\%SDK_ARCH%;%ROOT%Windows Kits\\10\\bin\\%SDK_VERSION%\\%SDK_ARCH%\\ucrt;%PATH%
set INCLUDE=%MSVC_ROOT%\\include;%SDK_INCLUDE%\\ucrt;%SDK_INCLUDE%\\shared;%SDK_INCLUDE%\\um;%SDK_INCLUDE%\\winrt;%SDK_INCLUDE%\\cppwinrt
set LIB=%MSVC_ROOT%\\lib\\%MSVC_ARCH%;%SDK_LIBS%\\ucrt\\%SDK_ARCH%;%SDK_LIBS%\\um\\%SDK_ARCH%
"""
  (OUTPUT / f"setup_{target}.bat").write_text(SETUP)

print(f"Total downloaded: {total_download>>20} MB")
print("Done!")

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