cpython/Tools/jit/_llvm.py

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"""Utilities for invoking LLVM tools."""
import asyncio
import functools
import os
import re
import shlex
import subprocess
import typing
_LLVM_VERSION = 18
_LLVM_VERSION_PATTERN = re.compile(rf"version\s+{_LLVM_VERSION}\.\d+\.\d+\S*\s+")
_P = typing.ParamSpec("_P")
_R = typing.TypeVar("_R")
_C = typing.Callable[_P, typing.Awaitable[_R]]
def _async_cache(f: _C[_P, _R]) -> _C[_P, _R]:
cache = {}
lock = asyncio.Lock()
@functools.wraps(f)
async def wrapper(
*args: _P.args, **kwargs: _P.kwargs # pylint: disable = no-member
) -> _R:
async with lock:
if args not in cache:
cache[args] = await f(*args, **kwargs)
return cache[args]
return wrapper
_CORES = asyncio.BoundedSemaphore(os.cpu_count() or 1)
async def _run(tool: str, args: typing.Iterable[str], echo: bool = False) -> str | None:
command = [tool, *args]
async with _CORES:
if echo:
print(shlex.join(command))
try:
process = await asyncio.create_subprocess_exec(
*command, stdout=subprocess.PIPE
)
except FileNotFoundError:
return None
out, _ = await process.communicate()
if process.returncode:
raise RuntimeError(f"{tool} exited with return code {process.returncode}")
return out.decode()
@_async_cache
async def _check_tool_version(name: str, *, echo: bool = False) -> bool:
output = await _run(name, ["--version"], echo=echo)
return bool(output and _LLVM_VERSION_PATTERN.search(output))
@_async_cache
async def _get_brew_llvm_prefix(*, echo: bool = False) -> str | None:
output = await _run("brew", ["--prefix", f"llvm@{_LLVM_VERSION}"], echo=echo)
return output and output.removesuffix("\n")
@_async_cache
async def _find_tool(tool: str, *, echo: bool = False) -> str | None:
# Unversioned executables:
path = tool
if await _check_tool_version(path, echo=echo):
return path
# Versioned executables:
path = f"{tool}-{_LLVM_VERSION}"
if await _check_tool_version(path, echo=echo):
return path
# Homebrew-installed executables:
prefix = await _get_brew_llvm_prefix(echo=echo)
if prefix is not None:
path = os.path.join(prefix, "bin", tool)
if await _check_tool_version(path, echo=echo):
return path
# Nothing found:
return None
async def maybe_run(
tool: str, args: typing.Iterable[str], echo: bool = False
) -> str | None:
"""Run an LLVM tool if it can be found. Otherwise, return None."""
path = await _find_tool(tool, echo=echo)
return path and await _run(path, args, echo=echo)
async def run(tool: str, args: typing.Iterable[str], echo: bool = False) -> str:
"""Run an LLVM tool if it can be found. Otherwise, raise RuntimeError."""
output = await maybe_run(tool, args, echo=echo)
if output is None:
raise RuntimeError(f"Can't find {tool}-{_LLVM_VERSION}!")
return output