setup.py

import os
import re
import subprocess
import sys
from pathlib import Path

from setuptools import Extension, setup
from setuptools.command.build_ext import build_ext

# Convert distutils Windows platform specifiers to CMake -A arguments
PLAT_TO_CMAKE = {
    "win32": "Win32",
    "win-amd64": "x64",
    "win-arm32": "ARM",
    "win-arm64": "ARM64",
}


class CMakeExtension(Extension):

  def __init__(self, name: str, sourcedir: str = "") -> None:
    super().__init__(name, sources=[])
    self.sourcedir = os.fspath(Path(sourcedir).resolve())


class CMakeBuild(build_ext):

  def build_extension(self, ext: CMakeExtension) -> None:
    # Must be in this form due to bug in .resolve() only fixed in Python 3.10+
    ext_fullpath = Path.cwd() / self.get_ext_fullpath(
        ext.name)  # type: ignore[no-untyped-call]
    extdir = ext_fullpath.parent.resolve()

    # Using this requires trailing slash for auto-detection & inclusion of
    # auxiliary "native" libs

    debug = int(os.environ.get("DEBUG",
                               0)) if self.debug is None else self.debug
    cfg = "Debug" if debug else "Release"

    # CMake lets you override the generator - we need to check this.
    # Can be set with Conda-Build, for example.
    cmake_generator = os.environ.get("CMAKE_GENERATOR", "")

    # Set Python_EXECUTABLE instead if you use PYBIND11_FINDPYTHON
    # EXAMPLE_VERSION_INFO shows you how to pass a value into the C++ code
    # from Python.
    cmake_args = [
        f"-DCMAKE_LIBRARY_OUTPUT_DIRECTORY={extdir}{os.sep}",
        f"-DPython_EXECUTABLE={sys.executable}",
        f"-DCMAKE_BUILD_TYPE={cfg}",  # not used on MSVC, but no harm
        f"-DTORCH_EXTENSION_NAME={ext.name.split('.')[-1]}"
    ]
    build_args = []
    # Adding CMake arguments set as environment variable
    # (needed e.g. to build for ARM OSx on conda-forge)
    if "CMAKE_ARGS" in os.environ:
      cmake_args += [
          item for item in os.environ["CMAKE_ARGS"].split(" ") if item
      ]

    if self.compiler.compiler_type != "msvc":
      # Using Ninja-build since it a) is available as a wheel and b)
      # multithreads automatically. MSVC would require all variables be
      # exported for Ninja to pick it up, which is a little tricky to do.
      # Users can override the generator with CMAKE_GENERATOR in CMake
      # 3.15+.
      if not cmake_generator or cmake_generator == "Ninja":
        try:
          import ninja  # noqa: F401

          ninja_executable_path = Path(ninja.BIN_DIR) / "ninja"
          cmake_args += [
              "-GNinja",
              f"-DCMAKE_MAKE_PROGRAM:FILEPATH={ninja_executable_path}",
          ]
        except ImportError:
          pass
    else:
      # Single config generators are handled "normally"
      single_config = any(x in cmake_generator for x in {"NMake", "Ninja"})

      # CMake allows an arch-in-generator style for backward compatibility
      contains_arch = any(x in cmake_generator for x in {"ARM", "Win64"})

      # Specify the arch if using MSVC generator, but only if it doesn't
      # contain a backward-compatibility arch spec already in the
      # generator name.
      if not single_config and not contains_arch:
        cmake_args += ["-A", PLAT_TO_CMAKE[self.plat_name]]

      # Multi-config generators have a different way to specify configs
      if not single_config:
        cmake_args += [
            f"-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{cfg.upper()}={extdir}"
        ]
        build_args += ["--config", cfg]

    if sys.platform.startswith("darwin"):
      # Cross-compile support for macOS - respect ARCHFLAGS if set
      archs = re.findall(r"-arch (\S+)", os.environ.get("ARCHFLAGS", ""))
      if archs:
        cmake_args += ["-DCMAKE_OSX_ARCHITECTURES={}".format(";".join(archs))]

    # Set CMAKE_BUILD_PARALLEL_LEVEL to control the parallel build level
    # across all generators.
    if "CMAKE_BUILD_PARALLEL_LEVEL" not in os.environ:
      # self.parallel is a Python 3 only way to set parallel jobs by hand
      # using -j in the build_ext call, not supported by pip or PyPA-build.
      if hasattr(self, "parallel") and self.parallel:
        # CMake 3.12+ only.
        build_args += [f"-j{self.parallel}"]

    build_temp = Path(self.build_temp) / ext.name
    if not build_temp.exists():
      build_temp.mkdir(parents=True)

    subprocess.run(["cmake", ext.sourcedir] + cmake_args,
                   cwd=build_temp,
                   check=True)
    subprocess.run(["cmake", "--build", "."] + build_args,
                   cwd=build_temp,
                   check=True)


setup(ext_modules=[CMakeExtension("minuet.nn.functional._C")],
      cmdclass={'build_ext': CMakeBuild},
      zip_safe=False)