setup.py

import os
import re
import subprocess
import sys
from datetime import date

import setuptools
import torch
from packaging import version as packaging_version
from torch.utils.cpp_extension import CUDA_HOME, BuildExtension, CUDAExtension


class CustomBuildExtension(BuildExtension):
    def build_extensions(self):
        for ext in self.extensions:
            if not "cxx" in ext.extra_compile_args:
                ext.extra_compile_args["cxx"] = []
            if not "nvcc" in ext.extra_compile_args:
                ext.extra_compile_args["nvcc"] = []
            if self.compiler.compiler_type == "msvc":
                ext.extra_compile_args["cxx"] += ext.extra_compile_args["msvc"]
                ext.extra_compile_args["nvcc"] += ext.extra_compile_args["nvcc_msvc"]
            else:
                ext.extra_compile_args["cxx"] += ext.extra_compile_args["gcc"]
        super().build_extensions()


def get_sm_targets() -> list[str]:
    nvcc_path = os.path.join(CUDA_HOME, "bin/nvcc") if CUDA_HOME else "nvcc"
    try:
        nvcc_output = subprocess.check_output([nvcc_path, "--version"]).decode()
        match = re.search(r"release (\d+\.\d+), V(\d+\.\d+\.\d+)", nvcc_output)
        if match:
            nvcc_version = match.group(2)
        else:
            raise Exception("nvcc version not found")
        print(f"Found nvcc version: {nvcc_version}")
    except:
        raise Exception("nvcc not found")

    support_sm120 = packaging_version.parse(nvcc_version) >= packaging_version.parse("12.8")

    install_mode = os.getenv("NUNCHAKU_INSTALL_MODE", "FAST")
    if install_mode == "FAST":
        ret = []
        for i in range(torch.cuda.device_count()):
            capability = torch.cuda.get_device_capability(i)
            sm = f"{capability[0]}{capability[1]}"
            if sm == "120" and support_sm120:
                sm = "120a"
            ret.append(sm)
        return ret
    elif install_mode == "ALL":
        # All supported architectures (except for experimental ones)
        sm_targets = ["75", "80", "86", "89", "90"]
        if support_sm120:
            sm_targets.append("120a")
        return sm_targets
    else:
        raise ValueError(f"Unknown install mode: {install_mode}")


FLUX_SOURCES = [
    "nunchaku/csrc/pybind.cpp",
]

ext_modules = []

# Check if CUDA is available
if torch.cuda.is_available() and CUDA_HOME is not None:
    sm_targets = get_sm_targets()
    arch_flags = [f"-gencode=arch=compute_{sm},code=sm_{sm}" for sm in sm_targets]
    
    ext_modules.append(
        CUDAExtension(
            "nunchaku._C",
            FLUX_SOURCES,
            extra_compile_args={
                "cxx": ["-O3", "-std=c++20"],
                "nvcc": [
                    "-O3",
                    "-std=c++20",
                    "--use_fast_math",
                    "-U__CUDA_NO_HALF_OPERATORS__",
                    "-U__CUDA_NO_HALF_CONVERSIONS__",
                    "-U__CUDA_NO_BFLOAT16_CONVERSIONS__",
                    "-U__CUDA_NO_HALF2_OPERATORS__",
                ] + arch_flags,
                "msvc": ["/std:c++20"],
                "gcc": ["-std=c++20"],
                "nvcc_msvc": [],
            },
            include_dirs=[
                "third_party/cutlass/include",
                "third_party/cutlass/tools/util/include",
            ],
        )
    )
else:
    print("CUDA not available. Installing CPU-only version.")

setuptools.setup(
    name="flux-kontext",
    packages=setuptools.find_packages(),
    ext_modules=ext_modules,
    cmdclass={"build_ext": CustomBuildExtension},
    zip_safe=False,
)