#!/usr/bin/env python3
import argparse
import contextlib
import functools
import os
try:
from os import process_cpu_count as cpu_count
except ImportError:
from os import cpu_count
import pathlib
import shutil
import subprocess
import sys
import sysconfig
import tempfile
CHECKOUT = pathlib.Path(__file__).parent.parent.parent
CROSS_BUILD_DIR = CHECKOUT / "cross-build"
BUILD_DIR = CROSS_BUILD_DIR / "build"
LOCAL_SETUP = CHECKOUT / "Modules" / "Setup.local"
LOCAL_SETUP_MARKER = "# Generated by Tools/wasm/wasi.py\n".encode("utf-8")
WASMTIME_VAR_NAME = "WASMTIME"
WASMTIME_HOST_RUNNER_VAR = f"{{{WASMTIME_VAR_NAME}}}"
def updated_env(updates={}):
"""Create a new dict representing the environment to use.
The changes made to the execution environment are printed out.
"""
env_defaults = {}
# https://reproducible-builds.org/docs/source-date-epoch/
git_epoch_cmd = ["git", "log", "-1", "--pretty=%ct"]
try:
epoch = subprocess.check_output(git_epoch_cmd, encoding="utf-8").strip()
env_defaults["SOURCE_DATE_EPOCH"] = epoch
except subprocess.CalledProcessError:
pass # Might be building from a tarball.
# This layering lets SOURCE_DATE_EPOCH from os.environ takes precedence.
environment = env_defaults | os.environ | updates
env_diff = {}
for key, value in environment.items():
if os.environ.get(key) != value:
env_diff[key] = value
print("🌎 Environment changes:")
for key in sorted(env_diff.keys()):
print(f" {key}={env_diff[key]}")
return environment
def subdir(working_dir, *, clean_ok=False):
"""Decorator to change to a working directory."""
def decorator(func):
@functools.wraps(func)
def wrapper(context):
nonlocal working_dir
if callable(working_dir):
working_dir = working_dir(context)
try:
tput_output = subprocess.check_output(["tput", "cols"],
encoding="utf-8")
except subprocess.CalledProcessError:
terminal_width = 80
else:
terminal_width = int(tput_output.strip())
print("⎯" * terminal_width)
print("📁", working_dir)
if (clean_ok and getattr(context, "clean", False) and
working_dir.exists()):
print(f"🚮 Deleting directory (--clean)...")
shutil.rmtree(working_dir)
working_dir.mkdir(parents=True, exist_ok=True)
with contextlib.chdir(working_dir):
return func(context, working_dir)
return wrapper
return decorator
def call(command, *, quiet, **kwargs):
"""Execute a command.
If 'quiet' is true, then redirect stdout and stderr to a temporary file.
"""
print("❯", " ".join(map(str, command)))
if not quiet:
stdout = None
stderr = None
else:
stdout = tempfile.NamedTemporaryFile("w", encoding="utf-8",
delete=False,
prefix="cpython-wasi-",
suffix=".log")
stderr = subprocess.STDOUT
print(f"📝 Logging output to {stdout.name} (--quiet)...")
subprocess.check_call(command, **kwargs, stdout=stdout, stderr=stderr)
def build_platform():
"""The name of the build/host platform."""
# Can also be found via `config.guess`.`
return sysconfig.get_config_var("BUILD_GNU_TYPE")
def build_python_path():
"""The path to the build Python binary."""
binary = BUILD_DIR / "python"
if not binary.is_file():
binary = binary.with_suffix(".exe")
if not binary.is_file():
raise FileNotFoundError("Unable to find `python(.exe)` in "
f"{BUILD_DIR}")
return binary
@subdir(BUILD_DIR, clean_ok=True)
def configure_build_python(context, working_dir):
"""Configure the build/host Python."""
if LOCAL_SETUP.exists():
print(f"👍 {LOCAL_SETUP} exists ...")
else:
print(f"📝 Touching {LOCAL_SETUP} ...")
LOCAL_SETUP.write_bytes(LOCAL_SETUP_MARKER)
configure = [os.path.relpath(CHECKOUT / 'configure', working_dir)]
if context.args:
configure.extend(context.args)
call(configure, quiet=context.quiet)
@subdir(BUILD_DIR)
def make_build_python(context, working_dir):
"""Make/build the build Python."""
call(["make", "--jobs", str(cpu_count()), "all"],
quiet=context.quiet)
binary = build_python_path()
cmd = [binary, "-c",
"import sys; "
"print(f'{sys.version_info.major}.{sys.version_info.minor}')"]
version = subprocess.check_output(cmd, encoding="utf-8").strip()
print(f"🎉 {binary} {version}")
def find_wasi_sdk():
"""Find the path to wasi-sdk."""
if wasi_sdk_path := os.environ.get("WASI_SDK_PATH"):
return pathlib.Path(wasi_sdk_path)
elif (default_path := pathlib.Path("/opt/wasi-sdk")).exists():
return default_path
def wasi_sdk_env(context):
"""Calculate environment variables for building with wasi-sdk."""
wasi_sdk_path = context.wasi_sdk_path
sysroot = wasi_sdk_path / "share" / "wasi-sysroot"
env = {"CC": "clang", "CPP": "clang-cpp", "CXX": "clang++",
"AR": "llvm-ar", "RANLIB": "ranlib"}
for env_var, binary_name in list(env.items()):
env[env_var] = os.fsdecode(wasi_sdk_path / "bin" / binary_name)
if wasi_sdk_path != pathlib.Path("/opt/wasi-sdk"):
for compiler in ["CC", "CPP", "CXX"]:
env[compiler] += f" --sysroot={sysroot}"
env["PKG_CONFIG_PATH"] = ""
env["PKG_CONFIG_LIBDIR"] = os.pathsep.join(
map(os.fsdecode,
[sysroot / "lib" / "pkgconfig",
sysroot / "share" / "pkgconfig"]))
env["PKG_CONFIG_SYSROOT_DIR"] = os.fsdecode(sysroot)
env["WASI_SDK_PATH"] = os.fsdecode(wasi_sdk_path)
env["WASI_SYSROOT"] = os.fsdecode(sysroot)
env["PATH"] = os.pathsep.join([os.fsdecode(wasi_sdk_path / "bin"),
os.environ["PATH"]])
return env
@subdir(lambda context: CROSS_BUILD_DIR / context.host_triple, clean_ok=True)
def configure_wasi_python(context, working_dir):
"""Configure the WASI/host build."""
if not context.wasi_sdk_path or not context.wasi_sdk_path.exists():
raise ValueError("WASI-SDK not found; "
"download from "
"https://github.com/WebAssembly/wasi-sdk and/or "
"specify via $WASI_SDK_PATH or --wasi-sdk")
config_site = os.fsdecode(CHECKOUT / "Tools" / "wasm" / "config.site-wasm32-wasi")
wasi_build_dir = working_dir.relative_to(CHECKOUT)
python_build_dir = BUILD_DIR / "build"
lib_dirs = list(python_build_dir.glob("lib.*"))
assert len(lib_dirs) == 1, f"Expected a single lib.* directory in {python_build_dir}"
lib_dir = os.fsdecode(lib_dirs[0])
pydebug = lib_dir.endswith("-pydebug")
python_version = lib_dir.removesuffix("-pydebug").rpartition("-")[-1]
sysconfig_data = f"{wasi_build_dir}/build/lib.wasi-wasm32-{python_version}"
if pydebug:
sysconfig_data += "-pydebug"
# Use PYTHONPATH to include sysconfig data which must be anchored to the
# WASI guest's `/` directory.
args = {"GUEST_DIR": "/",
"HOST_DIR": CHECKOUT,
"ENV_VAR_NAME": "PYTHONPATH",
"ENV_VAR_VALUE": f"/{sysconfig_data}",
"PYTHON_WASM": working_dir / "python.wasm"}
# Check dynamically for wasmtime in case it was specified manually via
# `--host-runner`.
if WASMTIME_HOST_RUNNER_VAR in context.host_runner:
if wasmtime := shutil.which("wasmtime"):
args[WASMTIME_VAR_NAME] = wasmtime
else:
raise FileNotFoundError("wasmtime not found; download from "
"https://github.com/bytecodealliance/wasmtime")
host_runner = context.host_runner.format_map(args)
env_additions = {"CONFIG_SITE": config_site, "HOSTRUNNER": host_runner}
build_python = os.fsdecode(build_python_path())
# The path to `configure` MUST be relative, else `python.wasm` is unable
# to find the stdlib due to Python not recognizing that it's being
# executed from within a checkout.
configure = [os.path.relpath(CHECKOUT / 'configure', working_dir),
f"--host={context.host_triple}",
f"--build={build_platform()}",
f"--with-build-python={build_python}"]
if pydebug:
configure.append("--with-pydebug")
if context.args:
configure.extend(context.args)
call(configure,
env=updated_env(env_additions | wasi_sdk_env(context)),
quiet=context.quiet)
python_wasm = working_dir / "python.wasm"
exec_script = working_dir / "python.sh"
with exec_script.open("w", encoding="utf-8") as file:
file.write(f'#!/bin/sh\nexec {host_runner} {python_wasm} "$@"\n')
exec_script.chmod(0o755)
print(f"🏃♀️ Created {exec_script} ... ")
sys.stdout.flush()
@subdir(lambda context: CROSS_BUILD_DIR / context.host_triple)
def make_wasi_python(context, working_dir):
"""Run `make` for the WASI/host build."""
call(["make", "--jobs", str(cpu_count()), "all"],
env=updated_env(),
quiet=context.quiet)
exec_script = working_dir / "python.sh"
subprocess.check_call([exec_script, "--version"])
def build_all(context):
"""Build everything."""
steps = [configure_build_python, make_build_python, configure_wasi_python,
make_wasi_python]
for step in steps:
step(context)
def clean_contents(context):
"""Delete all files created by this script."""
if CROSS_BUILD_DIR.exists():
print(f"🧹 Deleting {CROSS_BUILD_DIR} ...")
shutil.rmtree(CROSS_BUILD_DIR)
if LOCAL_SETUP.exists():
with LOCAL_SETUP.open("rb") as file:
if file.read(len(LOCAL_SETUP_MARKER)) == LOCAL_SETUP_MARKER:
print(f"🧹 Deleting generated {LOCAL_SETUP} ...")
def main():
default_host_runner = (f"{WASMTIME_HOST_RUNNER_VAR} run "
# Make sure the stack size will work for a pydebug
# build.
# Use 16 MiB stack.
"--wasm max-wasm-stack=16777216 "
# Use WASI 0.2 primitives.
"--wasi preview2 "
# Enable thread support; causes use of preview1.
#"--wasm threads=y --wasi threads=y "
# Map the checkout to / to load the stdlib from /Lib.
"--dir {HOST_DIR}::{GUEST_DIR} "
# Set PYTHONPATH to the sysconfig data.
"--env {ENV_VAR_NAME}={ENV_VAR_VALUE}")
parser = argparse.ArgumentParser()
subcommands = parser.add_subparsers(dest="subcommand")
build = subcommands.add_parser("build", help="Build everything")
configure_build = subcommands.add_parser("configure-build-python",
help="Run `configure` for the "
"build Python")
make_build = subcommands.add_parser("make-build-python",
help="Run `make` for the build Python")
configure_host = subcommands.add_parser("configure-host",
help="Run `configure` for the "
"host/WASI (pydebug builds "
"are inferred from the build "
"Python)")
make_host = subcommands.add_parser("make-host",
help="Run `make` for the host/WASI")
clean = subcommands.add_parser("clean", help="Delete files and directories "
"created by this script")
for subcommand in build, configure_build, make_build, configure_host, make_host:
subcommand.add_argument("--quiet", action="store_true", default=False,
dest="quiet",
help="Redirect output from subprocesses to a log file")
for subcommand in configure_build, configure_host:
subcommand.add_argument("--clean", action="store_true", default=False,
dest="clean",
help="Delete any relevant directories before building")
for subcommand in build, configure_build, configure_host:
subcommand.add_argument("args", nargs="*",
help="Extra arguments to pass to `configure`")
for subcommand in build, configure_host:
subcommand.add_argument("--wasi-sdk", type=pathlib.Path,
dest="wasi_sdk_path",
default=find_wasi_sdk(),
help="Path to wasi-sdk; defaults to "
"$WASI_SDK_PATH or /opt/wasi-sdk")
subcommand.add_argument("--host-runner", action="store",
default=default_host_runner, dest="host_runner",
help="Command template for running the WASI host "
"(default designed for wasmtime 14 or newer: "
f"`{default_host_runner}`)")
for subcommand in build, configure_host, make_host:
subcommand.add_argument("--host-triple", action="store", default="wasm32-wasip1",
help="The target triple for the WASI host build")
context = parser.parse_args()
dispatch = {"configure-build-python": configure_build_python,
"make-build-python": make_build_python,
"configure-host": configure_wasi_python,
"make-host": make_wasi_python,
"build": build_all,
"clean": clean_contents}
dispatch[context.subcommand](context)
if __name__ == "__main__":
main()
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