# This CPP builder is designed to support both Windows and Linux OS. # The design document please check this RFC: https://github.com/pytorch/pytorch/issues/124245 import copy import errno import functools import json import logging import os import platform import re import shlex import shutil import subprocess import sys import sysconfig import tempfile import textwrap import warnings from collections.abc import Sequence from ctypes import cdll from ctypes.util import find_library from pathlib import Path from typing import Any, Optional, Union import torch from torch._dynamo.utils import dynamo_timed from torch._inductor import config, exc from torch._inductor.cpu_vec_isa import invalid_vec_isa, VecISA from torch._inductor.runtime.runtime_utils import cache_dir from torch.torch_version import TorchVersion if config.is_fbcode(): from triton.fb import build_paths # noqa: F401 from triton.fb.build import _run_build_command from torch._inductor.fb.utils import ( log_global_cache_errors, log_global_cache_stats, log_global_cache_vals, use_global_cache, ) else: def log_global_cache_errors(*args: Any, **kwargs: Any) -> None: # type: ignore[misc] pass def log_global_cache_stats(*args: Any, **kwargs: Any) -> None: # type: ignore[misc] pass def log_global_cache_vals(*args: Any, **kwargs: Any) -> None: # type: ignore[misc] pass def use_global_cache() -> bool: # type: ignore[misc] return False # Windows need setup a temp dir to store .obj files. _BUILD_TEMP_DIR = "CxxBuild" _HERE = os.path.abspath(__file__) _TORCH_PATH = os.path.dirname(os.path.dirname(_HERE)) _LINKER_SCRIPT = os.path.join(_TORCH_PATH, "_inductor/script.ld") # initialize variables for compilation _IS_LINUX = sys.platform.startswith("linux") _IS_MACOS = sys.platform.startswith("darwin") _IS_WINDOWS = sys.platform == "win32" SUBPROCESS_DECODE_ARGS = ("utf-8",) if _IS_WINDOWS else () log = logging.getLogger(__name__) # =============================== toolchain =============================== @functools.lru_cache(1) def cpp_compiler_search(search: str) -> str: from torch._inductor.codecache import get_lock_dir, LOCK_TIMEOUT for cxx in search: try: if cxx is None: # gxx package is only available for Linux # according to https://anaconda.org/conda-forge/gxx/ if sys.platform != "linux": continue # Do not install GXX by default if not os.getenv("TORCH_INDUCTOR_INSTALL_GXX"): continue from torch.utils._filelock import FileLock lock_dir = get_lock_dir() lock = FileLock( os.path.join(lock_dir, "g++.lock"), timeout=LOCK_TIMEOUT ) with lock: cxx = install_gcc_via_conda() subprocess.check_output([cxx, "--version"]) return cxx except (subprocess.SubprocessError, FileNotFoundError, ImportError): continue raise exc.InvalidCxxCompiler def install_gcc_via_conda() -> str: """On older systems, this is a quick way to get a modern compiler""" prefix = os.path.join(cache_dir(), "gcc") cxx_path = os.path.join(prefix, "bin", "g++") if not os.path.exists(cxx_path): log.info("Downloading GCC via conda") conda = os.environ.get("CONDA_EXE", "conda") if conda is None: conda = shutil.which("conda") if conda is not None: subprocess.check_call( [ conda, "create", f"--prefix={prefix}", "--channel=conda-forge", "--quiet", "-y", "python=3.8", "gxx", ], stdout=subprocess.PIPE, ) return cxx_path @functools.lru_cache(None) def check_compiler_exist_windows(compiler: str) -> None: """ Check if compiler is ready, in case end user not activate MSVC environment. """ try: subprocess.check_output([compiler, "/help"], stderr=subprocess.STDOUT) except FileNotFoundError as exc: raise RuntimeError(f"Compiler: {compiler} is not found.") from exc except subprocess.SubprocessError: # Expected that some compiler(clang, clang++) is exist, but they not support `/help` args. pass def get_cpp_compiler() -> str: if _IS_WINDOWS: compiler = os.environ.get("CXX", "cl") check_compiler_exist_windows(compiler) else: if config.is_fbcode(): return build_paths.cc if isinstance(config.cpp.cxx, (list, tuple)): search = tuple(config.cpp.cxx) else: search = (config.cpp.cxx,) compiler = cpp_compiler_search(search) return compiler @functools.lru_cache(None) def _is_apple_clang(cpp_compiler: str) -> bool: version_string = subprocess.check_output([cpp_compiler, "--version"]).decode("utf8") return "Apple" in version_string.splitlines()[0] @functools.lru_cache(None) def _is_clang(cpp_compiler: str) -> bool: # Mac OS apple clang maybe named as gcc, need check compiler info. if sys.platform == "darwin": return _is_apple_clang(cpp_compiler) elif _IS_WINDOWS: # clang suite have many compilers, and only clang-cl is supported. if re.search(r"((clang$)|(clang\+\+$))", cpp_compiler): raise RuntimeError( "Please use clang-cl, due to torch.compile only support MSVC-like CLI (compiler flags syntax)." ) return bool(re.search(r"(clang-cl)", cpp_compiler)) return bool(re.search(r"(clang|clang\+\+)", cpp_compiler)) @functools.lru_cache(None) def _is_gcc(cpp_compiler: str) -> bool: # Since "clang++" ends with "g++", the regex match below would validate on it. if _is_clang(cpp_compiler): return False return bool(re.search(r"(gcc|g\+\+)", cpp_compiler)) @functools.lru_cache(None) def _is_msvc_cl(cpp_compiler: str) -> bool: if not _IS_WINDOWS: return False try: output_msg = ( subprocess.check_output([cpp_compiler, "/help"], stderr=subprocess.STDOUT) .strip() .decode(*SUBPROCESS_DECODE_ARGS) ) return "Microsoft" in output_msg.splitlines()[0] except FileNotFoundError: return False return False @functools.lru_cache(None) def _is_intel_compiler(cpp_compiler: str) -> bool: def _check_minimal_version(compiler_version: TorchVersion) -> None: """ On Windows: early version icx has `-print-file-name` issue, and can't preload correctly for inductor. """ min_version = "2024.2.1" if _IS_WINDOWS else "0.0.0" if compiler_version < TorchVersion(min_version): raise RuntimeError( f"Intel Compiler error: less than minimal version {min_version}." ) try: output_msg = ( subprocess.check_output( [cpp_compiler, "--version"], stderr=subprocess.DEVNULL ) .strip() .decode(*SUBPROCESS_DECODE_ARGS) ) is_intel_compiler = "Intel" in output_msg.splitlines()[0] if is_intel_compiler: if _IS_WINDOWS: if re.search(r"((icx$)|(icx-cc$))", cpp_compiler): raise RuntimeError( "Please use icx-cl, due to torch.compile only support MSVC-like CLI (compiler flags syntax)." ) # Version check icx_ver_search = re.search(r"(\d+[.]\d+[.]\d+[.]\d+)", output_msg) if icx_ver_search is not None: icx_ver = icx_ver_search.group(1) _check_minimal_version(TorchVersion(icx_ver)) return is_intel_compiler except FileNotFoundError: return False except subprocess.SubprocessError: # --version args not support. return False return False @functools.lru_cache(None) def is_gcc() -> bool: return _is_gcc(get_cpp_compiler()) @functools.lru_cache(None) def is_clang() -> bool: return _is_clang(get_cpp_compiler()) @functools.lru_cache(None) def is_intel_compiler() -> bool: return _is_intel_compiler(get_cpp_compiler()) @functools.lru_cache(None) def is_apple_clang() -> bool: return _is_apple_clang(get_cpp_compiler()) @functools.lru_cache(None) def is_msvc_cl() -> bool: return _is_msvc_cl(get_cpp_compiler()) def get_compiler_version_info(compiler: str) -> str: env = os.environ.copy() env["LC_ALL"] = "C" # Don't localize output try: version_string = subprocess.check_output( [compiler, "-v"], stderr=subprocess.STDOUT, env=env ).decode(*SUBPROCESS_DECODE_ARGS) except Exception: try: version_string = subprocess.check_output( [compiler, "--version"], stderr=subprocess.STDOUT, env=env ).decode(*SUBPROCESS_DECODE_ARGS) except Exception: return "" # Mutiple lines to one line string. version_string = version_string.replace("\r", "_") version_string = version_string.replace("\n", "_") return version_string # =============================== cpp builder =============================== def _append_list(dest_list: list[str], src_list: list[str]) -> None: dest_list.extend(copy.deepcopy(item) for item in src_list) def _remove_duplication_in_list(orig_list: list[str]) -> list[str]: new_list: list[str] = [] for item in orig_list: if item not in new_list: new_list.append(item) return new_list def _create_if_dir_not_exist(path_dir: str) -> None: if not os.path.exists(path_dir): try: Path(path_dir).mkdir(parents=True, exist_ok=True) except OSError as exc: # Guard against race condition if exc.errno != errno.EEXIST: raise RuntimeError( # noqa: TRY200 (Use `raise from`) f"Fail to create path {path_dir}" ) def _remove_dir(path_dir: str) -> None: if os.path.exists(path_dir): for root, dirs, files in os.walk(path_dir, topdown=False): for name in files: file_path = os.path.join(root, name) os.remove(file_path) for name in dirs: dir_path = os.path.join(root, name) os.rmdir(dir_path) os.rmdir(path_dir) def _run_compile_cmd(cmd_line: str, cwd: str) -> None: cmd = shlex.split(cmd_line) try: subprocess.check_output(args=cmd, cwd=cwd, stderr=subprocess.STDOUT) except subprocess.CalledProcessError as e: output = e.output.decode("utf-8") openmp_problem = "'omp.h' file not found" in output or "libomp" in output if openmp_problem and sys.platform == "darwin": instruction = ( "\n\nOpenMP support not found. Please try one of the following solutions:\n" "(1) Set the `CXX` environment variable to a compiler other than Apple clang++/g++ " "that has builtin OpenMP support;\n" "(2) install OpenMP via conda: `conda install llvm-openmp`;\n" "(3) install libomp via brew: `brew install libomp`;\n" "(4) manually setup OpenMP and set the `OMP_PREFIX` environment variable to point to a path" " with `include/omp.h` under it." ) output += instruction raise exc.CppCompileError(cmd, output) from e def run_compile_cmd(cmd_line: str, cwd: str) -> None: with dynamo_timed("compile_file"): _run_compile_cmd(cmd_line, cwd) def normalize_path_separator(orig_path: str) -> str: if _IS_WINDOWS: return orig_path.replace(os.sep, "/") return orig_path class BuildOptionsBase: """ This is the Base class for store cxx build options, as a template. Acturally, to build a cxx shared library. We just need to select a compiler and maintains the suitable args. """ def __init__( self, compiler: str = "", definitions: Optional[list[str]] = None, include_dirs: Optional[list[str]] = None, cflags: Optional[list[str]] = None, ldflags: Optional[list[str]] = None, libraries_dirs: Optional[list[str]] = None, libraries: Optional[list[str]] = None, passthrough_args: Optional[list[str]] = None, aot_mode: bool = False, use_relative_path: bool = False, compile_only: bool = False, ) -> None: self._compiler = compiler self._definitions: list[str] = definitions or [] self._include_dirs: list[str] = include_dirs or [] self._cflags: list[str] = cflags or [] self._ldflags: list[str] = ldflags or [] self._libraries_dirs: list[str] = libraries_dirs or [] self._libraries: list[str] = libraries or [] # Some args is hard to abstract to OS compatable, passthrough it directly. self._passthrough_args: list[str] = passthrough_args or [] self._aot_mode: bool = aot_mode self._use_relative_path: bool = use_relative_path self._compile_only: bool = compile_only def _process_compile_only_options(self) -> None: if self._compile_only: self._libraries_dirs = [] self._libraries = [] def _remove_duplicate_options(self) -> None: self._definitions = _remove_duplication_in_list(self._definitions) self._include_dirs = _remove_duplication_in_list(self._include_dirs) self._cflags = _remove_duplication_in_list(self._cflags) self._ldflags = _remove_duplication_in_list(self._ldflags) self._libraries_dirs = _remove_duplication_in_list(self._libraries_dirs) self._libraries = _remove_duplication_in_list(self._libraries) self._passthrough_args = _remove_duplication_in_list(self._passthrough_args) def _finalize_options(self) -> None: self._process_compile_only_options() self._remove_duplicate_options() def get_compiler(self) -> str: return self._compiler def get_definitions(self) -> list[str]: return self._definitions def get_include_dirs(self) -> list[str]: return self._include_dirs def get_cflags(self) -> list[str]: return self._cflags def get_ldflags(self) -> list[str]: return self._ldflags def get_libraries_dirs(self) -> list[str]: return self._libraries_dirs def get_libraries(self) -> list[str]: return self._libraries def get_passthrough_args(self) -> list[str]: return self._passthrough_args def get_aot_mode(self) -> bool: return self._aot_mode def get_use_relative_path(self) -> bool: return self._use_relative_path def get_compile_only(self) -> bool: return self._compile_only def save_flags_to_json(self, file: str) -> None: attrs = { "compiler": self.get_compiler(), "definitions": self.get_definitions(), "include_dirs": self.get_include_dirs(), "cflags": self.get_cflags(), "ldflags": self.get_ldflags(), "libraries_dirs": self.get_libraries_dirs(), "libraries": self.get_libraries(), "passthrough_args": self.get_passthrough_args(), "aot_mode": self.get_aot_mode(), "use_relative_path": self.get_use_relative_path(), "compile_only": self.get_compile_only(), } with open(file, "w") as f: json.dump(attrs, f) def _get_warning_all_cflag(warning_all: bool = True) -> list[str]: if not _IS_WINDOWS: return ["Wall"] if warning_all else [] else: return [] def _get_cpp_std_cflag(std_num: str = "c++17") -> list[str]: if _IS_WINDOWS: """ On Windows, only c++20 can support `std::enable_if_t`. Ref: https://learn.microsoft.com/en-us/cpp/overview/cpp-conformance-improvements-2019?view=msvc-170#checking-for-abstract-class-types # noqa: B950 Note: Only setup c++20 for Windows inductor. I tried to upgrade all project to c++20, but it is failed: https://github.com/pytorch/pytorch/pull/131504 """ std_num = "c++20" return [f"std:{std_num}"] else: return [f"std={std_num}"] def _get_os_related_cpp_cflags(cpp_compiler: str) -> list[str]: if _IS_WINDOWS: cflags = [ "wd4819", "wd4251", "wd4244", "wd4267", "wd4275", "wd4018", "wd4190", "wd4624", "wd4067", "wd4068", "EHsc", ] else: cflags = ["Wno-unused-variable", "Wno-unknown-pragmas"] if _is_clang(cpp_compiler): ignored_optimization_argument = ( "Werror=ignored-optimization-argument" if config.aot_inductor.raise_error_on_ignored_optimization else "Wno-ignored-optimization-argument" ) cflags.append(ignored_optimization_argument) return cflags def _get_ffast_math_flags() -> list[str]: # ffast-math is equivalent to these flags as in # https://github.com/gcc-mirror/gcc/blob/4700ad1c78ccd7767f846802fca148b2ea9a1852/gcc/opts.cc#L3458-L3468 # however gcc<13 sets the FTZ/DAZ flags for runtime on x86 even if we have # -ffast-math -fno-unsafe-math-optimizations because the flags for runtime # are added by linking in crtfastmath.o. This is done by the spec file which # only does globbing for -ffast-math. flags = [ "fno-trapping-math", "funsafe-math-optimizations", "ffinite-math-only", "fno-signed-zeros", "fno-math-errno", ] if is_gcc(): flags.append("fexcess-precision=fast") return flags def _get_optimization_cflags( cpp_compiler: str, min_optimize: bool = False ) -> list[str]: if _IS_WINDOWS: return ["O1" if min_optimize else "O2"] else: cflags = ( ["O0", "g"] if config.aot_inductor.debug_compile else ["O1" if min_optimize else "O3", "DNDEBUG"] ) cflags += _get_ffast_math_flags() cflags.append("fno-finite-math-only") if not config.cpp.enable_unsafe_math_opt_flag: cflags.append("fno-unsafe-math-optimizations") cflags.append(f"ffp-contract={config.cpp.enable_floating_point_contract_flag}") if sys.platform != "darwin": # on macos, unknown argument: '-fno-tree-loop-vectorize' if _is_gcc(cpp_compiler): cflags.append("fno-tree-loop-vectorize") # https://stackoverflow.com/questions/65966969/why-does-march-native-not-work-on-apple-m1 # `-march=native` is unrecognized option on M1 if not config.is_fbcode(): if platform.machine() == "ppc64le": cflags.append("mcpu=native") else: cflags.append("march=native") return cflags def _get_shared_cflag(compile_only: bool) -> list[str]: if _IS_WINDOWS: """ MSVC `/MD` using python `ucrtbase.dll` lib as runtime. https://learn.microsoft.com/en-us/cpp/c-runtime-library/crt-library-features?view=msvc-170 """ SHARED_FLAG = ["DLL", "MD"] else: if compile_only: return ["fPIC"] if platform.system() == "Darwin" and "clang" in get_cpp_compiler(): # This causes undefined symbols to behave the same as linux return ["shared", "fPIC", "undefined dynamic_lookup"] else: return ["shared", "fPIC"] return SHARED_FLAG def get_cpp_options( cpp_compiler: str, compile_only: bool, warning_all: bool = True, extra_flags: Sequence[str] = (), min_optimize: bool = False, ) -> tuple[list[str], list[str], list[str], list[str], list[str], list[str], list[str]]: definitions: list[str] = [] include_dirs: list[str] = [] cflags: list[str] = [] ldflags: list[str] = [] libraries_dirs: list[str] = [] libraries: list[str] = [] passthrough_args: list[str] = [] cflags = ( _get_shared_cflag(compile_only) + _get_optimization_cflags(cpp_compiler, min_optimize) + _get_warning_all_cflag(warning_all) + _get_cpp_std_cflag() + _get_os_related_cpp_cflags(cpp_compiler) ) passthrough_args.append(" ".join(extra_flags)) return ( definitions, include_dirs, cflags, ldflags, libraries_dirs, libraries, passthrough_args, ) class CppOptions(BuildOptionsBase): """ This class is inherited from BuildOptionsBase, and as cxx build options. This option need contains basic cxx build option, which contains: 1. OS related args. 2. Toolchains related args. 3. Cxx standard related args. Note: 1. This Options is good for assist modules build, such as x86_isa_help. """ def __init__( self, compile_only: bool = False, warning_all: bool = True, extra_flags: Sequence[str] = (), use_relative_path: bool = False, compiler: str = "", min_optimize: bool = False, ) -> None: super().__init__() self._compiler = compiler if compiler else get_cpp_compiler() self._use_relative_path = use_relative_path self._compile_only = compile_only ( definitions, include_dirs, cflags, ldflags, libraries_dirs, libraries, passthrough_args, ) = get_cpp_options( cpp_compiler=self._compiler, compile_only=compile_only, extra_flags=extra_flags, warning_all=warning_all, min_optimize=min_optimize, ) _append_list(self._definitions, definitions) _append_list(self._include_dirs, include_dirs) _append_list(self._cflags, cflags) _append_list(self._ldflags, ldflags) _append_list(self._libraries_dirs, libraries_dirs) _append_list(self._libraries, libraries) _append_list(self._passthrough_args, passthrough_args) self._finalize_options() def _get_glibcxx_abi_build_flags() -> list[str]: if not _IS_WINDOWS: return ["-D_GLIBCXX_USE_CXX11_ABI=" + str(int(torch._C._GLIBCXX_USE_CXX11_ABI))] else: return [] def _get_torch_cpp_wrapper_definition() -> list[str]: return ["TORCH_INDUCTOR_CPP_WRAPPER", "STANDALONE_TORCH_HEADER"] def _use_custom_generated_macros() -> list[str]: return [" C10_USING_CUSTOM_GENERATED_MACROS"] def _use_fb_internal_macros() -> list[str]: if not _IS_WINDOWS: if config.is_fbcode(): fb_internal_macros = [ "C10_USE_GLOG", "C10_USE_MINIMAL_GLOG", "C10_DISABLE_TENSORIMPL_EXTENSIBILITY", ] return fb_internal_macros else: return [] else: return [] def _setup_standard_sys_libs( cpp_compiler: str, aot_mode: bool, use_relative_path: bool, ) -> tuple[list[str], list[str], list[str]]: cflags: list[str] = [] include_dirs: list[str] = [] passthrough_args: list[str] = [] if _IS_WINDOWS: return cflags, include_dirs, passthrough_args if config.is_fbcode(): # TODO(T203137008) Can we unify these flags with triton_cc_command? cflags.append("nostdinc") # Note that the order of include paths do matter, as a result # we need to have several branches interleaved here include_dirs.append(build_paths.sleef_include) include_dirs.append(build_paths.openmp_include) include_dirs.append(build_paths.python_include) include_dirs.append(build_paths.cc_include) include_dirs.append(build_paths.libgcc_include) include_dirs.append(build_paths.libgcc_arch_include) include_dirs.append(build_paths.libgcc_backward_include) include_dirs.append(build_paths.glibc_include) include_dirs.append(build_paths.linux_kernel_include) include_dirs.append("include") if aot_mode and not use_relative_path: linker_script = _LINKER_SCRIPT else: linker_script = os.path.basename(_LINKER_SCRIPT) if _is_clang(cpp_compiler): passthrough_args.append(" --rtlib=compiler-rt") passthrough_args.append(" -fuse-ld=lld") passthrough_args.append(f" -Wl,--script={linker_script}") passthrough_args.append(" -B" + build_paths.glibc_lib) passthrough_args.append(" -L" + build_paths.glibc_lib) return cflags, include_dirs, passthrough_args def _get_build_args_of_chosen_isa(vec_isa: VecISA) -> tuple[list[str], list[str]]: macros: list[str] = [] build_flags: list[str] = [] if vec_isa != invalid_vec_isa: # Add Windows support later. macros.extend(copy.deepcopy(x) for x in vec_isa.build_macro()) build_flags = [vec_isa.build_arch_flags()] if config.is_fbcode(): cap = str(vec_isa).upper() macros = [ f"CPU_CAPABILITY={cap}", f"CPU_CAPABILITY_{cap}", f"HAVE_{cap}_CPU_DEFINITION", ] return macros, build_flags def _get_torch_related_args( include_pytorch: bool, aot_mode: bool ) -> tuple[list[str], list[str], list[str]]: from torch.utils.cpp_extension import include_paths, TORCH_LIB_PATH include_dirs = include_paths() libraries_dirs = [TORCH_LIB_PATH] libraries = [] if sys.platform != "darwin" and not config.is_fbcode(): libraries = ["torch", "torch_cpu"] if not aot_mode: libraries.append("torch_python") if _IS_WINDOWS: libraries.append("sleef") return include_dirs, libraries_dirs, libraries def _get_python_include_dirs() -> list[str]: include_dir = Path(sysconfig.get_path("include")) # On Darwin Python executable from a framework can return # non-existing /Library/Python/... include path, in which case # one should use Headers folder from the framework if not include_dir.exists() and platform.system() == "Darwin": std_lib = Path(sysconfig.get_path("stdlib")) include_dir = (std_lib.parent.parent / "Headers").absolute() if not (include_dir / "Python.h").exists(): warnings.warn(f"Can't find Python.h in {str(include_dir)}") return [str(include_dir)] def _get_python_related_args() -> tuple[list[str], list[str]]: python_include_dirs = _get_python_include_dirs() python_include_path = sysconfig.get_path( "include", scheme="nt" if _IS_WINDOWS else "posix_prefix" ) if python_include_path is not None: python_include_dirs.append(python_include_path) if _IS_WINDOWS: python_lib_path = [ str( ( Path(sysconfig.get_path("include", scheme="nt")).parent / "libs" ).absolute() ) ] else: python_lib_path = [sysconfig.get_config_var("LIBDIR")] if config.is_fbcode(): python_include_dirs.append(build_paths.python_include) return python_include_dirs, python_lib_path @functools.lru_cache(None) def is_conda_llvm_openmp_installed() -> bool: try: command = "conda list llvm-openmp --json" output = subprocess.check_output(command.split()).decode("utf8") return len(json.loads(output)) > 0 except (subprocess.SubprocessError, FileNotFoundError): return False @functools.lru_cache(None) def homebrew_libomp() -> tuple[bool, str]: try: # check if `brew` is installed subprocess.check_output(["which", "brew"]) # get the location of `libomp` if it is installed # this is the location that `libomp` **would** be installed # see https://github.com/Homebrew/brew/issues/10261#issuecomment-756563567 for details libomp_path = ( subprocess.check_output(["brew", "--prefix", "libomp"]) .decode("utf8") .strip() ) # check if `libomp` is installed omp_available = os.path.exists(libomp_path) return omp_available, libomp_path except subprocess.SubprocessError: return False, "" @functools.lru_cache(None) def perload_clang_libomp_win(cpp_compiler: str, omp_name: str) -> None: try: output = subprocess.check_output([cpp_compiler, "-print-file-name=bin"]).decode( "utf8" ) omp_path = os.path.join(output.rstrip(), omp_name) if os.path.isfile(omp_path): os.environ["KMP_DUPLICATE_LIB_OK"] = "TRUE" cdll.LoadLibrary(omp_path) except subprocess.SubprocessError: pass @functools.lru_cache(None) def perload_icx_libomp_win(cpp_compiler: str) -> None: def _load_icx_built_in_lib_by_name(cpp_compiler: str, lib_name: str) -> bool: try: output = subprocess.check_output( [cpp_compiler, f"-print-file-name={lib_name}"], stderr=subprocess.DEVNULL, ).decode(*SUBPROCESS_DECODE_ARGS) omp_path = output.rstrip() if os.path.isfile(omp_path): os.environ["KMP_DUPLICATE_LIB_OK"] = "TRUE" cdll.LoadLibrary(omp_path) return True except subprocess.SubprocessError: pass return False """ Intel Compiler implenmented more math libraries than clang, for performance proposal. We need preload them like openmp library. """ preload_list = [ "libiomp5md.dll", # openmp "svml_dispmd.dll", # svml library "libmmd.dll", # libm ] for lib_name in preload_list: _load_icx_built_in_lib_by_name(cpp_compiler, lib_name) def _get_openmp_args( cpp_compiler: str, ) -> tuple[list[str], list[str], list[str], list[str], list[str], list[str]]: cflags: list[str] = [] ldflags: list[str] = [] include_dir_paths: list[str] = [] lib_dir_paths: list[str] = [] libs: list[str] = [] passthrough_args: list[str] = [] if _IS_MACOS: # Per https://mac.r-project.org/openmp/ right way to pass `openmp` flags to MacOS is via `-Xclang` cflags.append("Xclang") cflags.append("fopenmp") # only Apple builtin compilers (Apple Clang++) require openmp omp_available = not _is_apple_clang(cpp_compiler) # check the `OMP_PREFIX` environment first omp_prefix = os.getenv("OMP_PREFIX") if omp_prefix is not None: header_path = os.path.join(omp_prefix, "include", "omp.h") valid_env = os.path.exists(header_path) if valid_env: include_dir_paths.append(os.path.join(omp_prefix, "include")) lib_dir_paths.append(os.path.join(omp_prefix, "lib")) else: warnings.warn("environment variable `OMP_PREFIX` is invalid.") omp_available = omp_available or valid_env if not omp_available: libs.append("omp") # prefer to use openmp from `conda install llvm-openmp` conda_prefix = os.getenv("CONDA_PREFIX") if not omp_available and conda_prefix is not None: omp_available = is_conda_llvm_openmp_installed() if omp_available: conda_lib_path = os.path.join(conda_prefix, "lib") include_dir_paths.append(os.path.join(conda_prefix, "include")) lib_dir_paths.append(conda_lib_path) # Prefer Intel OpenMP on x86 machine if os.uname().machine == "x86_64" and os.path.exists( os.path.join(conda_lib_path, "libiomp5.dylib") ): libs.append("iomp5") # next, try to use openmp from `brew install libomp` if not omp_available: omp_available, libomp_path = homebrew_libomp() if omp_available: include_dir_paths.append(os.path.join(libomp_path, "include")) lib_dir_paths.append(os.path.join(libomp_path, "lib")) # if openmp is still not available, we let the compiler to have a try, # and raise error together with instructions at compilation error later elif _IS_WINDOWS: """ On Windows, `clang` and `icx` have their specific openmp implenmention. And the openmp lib is in compiler's some sub-directory. For dynamic library(DLL) load, the Windows native APIs are `LoadLibraryA` and `LoadLibraryExA`, and their search dependencies have some rules: https://learn.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryexa#searching-for-dlls-and-dependencies In some case, the rules may not include compiler's sub-directories. So, it can't search and load compiler's openmp library correctly. And then, the whole application would be broken. To avoid the openmp load failed, we can automatic locate the openmp binary and preload it. 1. For clang, the function is `perload_clang_libomp_win`. 2. For icx, the function is `perload_icx_libomp_win`. """ if _is_clang(cpp_compiler): cflags.append("openmp") libs.append("libomp") perload_clang_libomp_win(cpp_compiler, "libomp.dll") elif _is_intel_compiler(cpp_compiler): cflags.append("Qiopenmp") libs.append("libiomp5md") perload_icx_libomp_win(cpp_compiler) else: # /openmp, /openmp:llvm # llvm on Windows, new openmp: https://devblogs.microsoft.com/cppblog/msvc-openmp-update/ # msvc openmp: https://learn.microsoft.com/zh-cn/cpp/build/reference/openmp-enable-openmp-2-0-support?view=msvc-170 cflags.append("openmp") cflags.append("openmp:experimental") # MSVC CL else: if config.is_fbcode(): include_dir_paths.append(build_paths.openmp_include) openmp_lib = build_paths.openmp_lib_so fb_openmp_extra_flags = f"-Wp,-fopenmp {openmp_lib}" passthrough_args.append(fb_openmp_extra_flags) libs.append("omp") else: if _is_clang(cpp_compiler): # TODO: fix issue, can't find omp.h cflags.append("fopenmp") libs.append("gomp") elif _is_intel_compiler(cpp_compiler): cflags.append("fiopenmp") else: cflags.append("fopenmp") libs.append("gomp") return cflags, ldflags, include_dir_paths, lib_dir_paths, libs, passthrough_args def get_mmap_self_macro(use_mmap_weights: bool) -> list[str]: macros = [] if use_mmap_weights: macros.append(" USE_MMAP_SELF") return macros def get_cpp_torch_options( cpp_compiler: str, vec_isa: VecISA, include_pytorch: bool, aot_mode: bool, compile_only: bool, use_relative_path: bool, use_mmap_weights: bool, ) -> tuple[list[str], list[str], list[str], list[str], list[str], list[str], list[str]]: definitions: list[str] = [] include_dirs: list[str] = [] cflags: list[str] = [] ldflags: list[str] = [] libraries_dirs: list[str] = [] libraries: list[str] = [] passthrough_args: list[str] = [] torch_cpp_wrapper_definitions = _get_torch_cpp_wrapper_definition() use_custom_generated_macros_definitions = _use_custom_generated_macros() ( sys_libs_cflags, sys_libs_include_dirs, sys_libs_passthrough_args, ) = _setup_standard_sys_libs(cpp_compiler, aot_mode, use_relative_path) isa_macros, isa_ps_args_build_flags = _get_build_args_of_chosen_isa(vec_isa) ( torch_include_dirs, torch_libraries_dirs, torch_libraries, ) = _get_torch_related_args(include_pytorch=include_pytorch, aot_mode=aot_mode) python_include_dirs, python_libraries_dirs = _get_python_related_args() ( omp_cflags, omp_ldflags, omp_include_dir_paths, omp_lib_dir_paths, omp_lib, omp_passthrough_args, ) = _get_openmp_args(cpp_compiler) cxx_abi_passthrough_args = _get_glibcxx_abi_build_flags() fb_macro_passthrough_args = _use_fb_internal_macros() mmap_self_macros = get_mmap_self_macro(use_mmap_weights) definitions = ( torch_cpp_wrapper_definitions + use_custom_generated_macros_definitions + isa_macros + fb_macro_passthrough_args + mmap_self_macros ) include_dirs = ( sys_libs_include_dirs + python_include_dirs + torch_include_dirs + omp_include_dir_paths ) cflags = sys_libs_cflags + omp_cflags ldflags = omp_ldflags libraries_dirs = python_libraries_dirs + torch_libraries_dirs + omp_lib_dir_paths libraries = torch_libraries + omp_lib passthrough_args = ( sys_libs_passthrough_args + isa_ps_args_build_flags + cxx_abi_passthrough_args + omp_passthrough_args ) return ( definitions, include_dirs, cflags, ldflags, libraries_dirs, libraries, passthrough_args, ) class CppTorchOptions(CppOptions): """ This class is inherited from CppTorchOptions, which automatic contains base cxx build options. And then it will maintains torch related build args. 1. Torch include_directories, libraries, libraries_directories. 2. Python include_directories, libraries, libraries_directories. 3. OpenMP related. 4. Torch MACROs. 5. MISC """ def __init__( self, vec_isa: VecISA = invalid_vec_isa, include_pytorch: bool = False, warning_all: bool = True, aot_mode: bool = False, compile_only: bool = False, use_relative_path: bool = False, use_mmap_weights: bool = False, shared: bool = True, extra_flags: Sequence[str] = (), compiler: str = "", min_optimize: bool = False, ) -> None: super().__init__( compile_only=compile_only, warning_all=warning_all, extra_flags=extra_flags, use_relative_path=use_relative_path, compiler=compiler, min_optimize=min_optimize, ) self._aot_mode = aot_mode ( torch_definitions, torch_include_dirs, torch_cflags, torch_ldflags, torch_libraries_dirs, torch_libraries, torch_passthrough_args, ) = get_cpp_torch_options( cpp_compiler=self._compiler, vec_isa=vec_isa, include_pytorch=include_pytorch, aot_mode=aot_mode, compile_only=compile_only, use_relative_path=use_relative_path, use_mmap_weights=use_mmap_weights, ) _append_list(self._definitions, torch_definitions) _append_list(self._include_dirs, torch_include_dirs) _append_list(self._cflags, torch_cflags) _append_list(self._ldflags, torch_ldflags) _append_list(self._libraries_dirs, torch_libraries_dirs) _append_list(self._libraries, torch_libraries) _append_list(self._passthrough_args, torch_passthrough_args) self._finalize_options() def _set_gpu_runtime_env() -> None: if ( config.is_fbcode() and torch.version.hip is None and "CUDA_HOME" not in os.environ and "CUDA_PATH" not in os.environ ): os.environ["CUDA_HOME"] = build_paths.sdk_home @functools.lru_cache(8) def _find_libcudart_static(path: str) -> Optional[Path]: lib_dirs = list(Path(path).rglob("libcudart_static.a")) if lib_dirs: return lib_dirs[0].resolve().parent log_msg = f'"libcudart_static.a" not found under {path}' log.info(log_msg) return None def _transform_cuda_paths(lpaths: list[str]) -> None: # This handles two cases: # 1. Cases where libs are in (e.g.) lib/cuda-12 and lib/cuda-12/stubs # 2. Linux machines may have CUDA installed under either lib64/ or lib/ for i, path in enumerate(lpaths): if "CUDA_HOME" in os.environ and path.startswith(os.environ["CUDA_HOME"]): lib_dir: Optional[Path] = _find_libcudart_static(path) if lib_dir is None: continue lpaths[i] = str(lib_dir) stub_dir = lib_dir / "stubs" if stub_dir.exists(): lpaths.append(str(stub_dir)) def get_cpp_torch_device_options( device_type: str, aot_mode: bool = False, compile_only: bool = False, ) -> tuple[list[str], list[str], list[str], list[str], list[str], list[str], list[str]]: definitions: list[str] = [] include_dirs: list[str] = [] cflags: list[str] = [] ldflags: list[str] = [] libraries_dirs: list[str] = [] libraries: list[str] = [] passthrough_args: list[str] = [] if ( config.is_fbcode() and "CUDA_HOME" not in os.environ and "CUDA_PATH" not in os.environ ): os.environ["CUDA_HOME"] = build_paths.sdk_home _set_gpu_runtime_env() from torch.utils import cpp_extension include_dirs = cpp_extension.include_paths(device_type) libraries_dirs = cpp_extension.library_paths(device_type) if device_type == "cuda": definitions.append(" USE_ROCM" if torch.version.hip else " USE_CUDA") if torch.version.hip is not None: if config.is_fbcode(): libraries += ["amdhip64"] else: libraries += ["c10_hip", "torch_hip"] definitions.append(" __HIP_PLATFORM_AMD__") else: if config.is_fbcode(): libraries += ["cuda"] else: libraries += ["c10_cuda", "cuda", "torch_cuda"] _transform_cuda_paths(libraries_dirs) if device_type == "xpu": definitions.append(" USE_XPU") # Suppress multi-line comment warnings in sycl headers cflags += ["Wno-comment"] libraries += ["c10_xpu", "sycl", "ze_loader", "torch_xpu"] if not find_library("ze_loader"): raise OSError( "Intel GPU driver is not properly installed, please follow the instruction " "in https://github.com/pytorch/pytorch?tab=readme-ov-file#intel-gpu-support." ) if aot_mode: if config.is_fbcode(): from torch._inductor.codecache import cpp_prefix_path cpp_prefix_include_dir = [f"{os.path.dirname(cpp_prefix_path())}"] include_dirs += cpp_prefix_include_dir if config.is_fbcode(): include_dirs.append(build_paths.sdk_include) if aot_mode and device_type == "cuda": if torch.version.hip is None: if not compile_only: # Only add link args, when compile_only is false. passthrough_args = ["-Wl,-Bstatic -lcudart_static -Wl,-Bdynamic"] return ( definitions, include_dirs, cflags, ldflags, libraries_dirs, libraries, passthrough_args, ) class CppTorchDeviceOptions(CppTorchOptions): """ This class is inherited from CppTorchOptions, which automatic contains base cxx build options and torch common build options. And then it will maintains cuda/xpu device related build args. """ def __init__( self, vec_isa: VecISA = invalid_vec_isa, include_pytorch: bool = False, device_type: str = "cuda", aot_mode: bool = False, compile_only: bool = False, use_relative_path: bool = False, use_mmap_weights: bool = False, shared: bool = True, extra_flags: Sequence[str] = (), min_optimize: bool = False, ) -> None: super().__init__( vec_isa=vec_isa, include_pytorch=include_pytorch, aot_mode=aot_mode, compile_only=compile_only, use_relative_path=use_relative_path, use_mmap_weights=use_mmap_weights, extra_flags=extra_flags, min_optimize=min_optimize, ) device_definitions: list[str] = [] device_include_dirs: list[str] = [] device_cflags: list[str] = [] device_ldflags: list[str] = [] device_libraries_dirs: list[str] = [] device_libraries: list[str] = [] device_passthrough_args: list[str] = [] ( device_definitions, device_include_dirs, device_cflags, device_ldflags, device_libraries_dirs, device_libraries, device_passthrough_args, ) = get_cpp_torch_device_options( device_type=device_type, aot_mode=aot_mode, compile_only=compile_only ) _append_list(self._definitions, device_definitions) _append_list(self._include_dirs, device_include_dirs) _append_list(self._cflags, device_cflags) _append_list(self._ldflags, device_ldflags) _append_list(self._libraries_dirs, device_libraries_dirs) _append_list(self._libraries, device_libraries) _append_list(self._passthrough_args, device_passthrough_args) self._finalize_options() def _finalize_options(self) -> None: super()._finalize_options() if config.is_fbcode(): # Re-order library search paths in case there are lib conflicts # that also live in the FBCode python lib dir. _, python_lib_dirs = _get_python_related_args() assert len(python_lib_dirs) == 1, f"Python lib dirs: {python_lib_dirs}" if python_lib_dirs[0] in self._libraries_dirs: self._libraries_dirs.remove(python_lib_dirs[0]) self._libraries_dirs.append(python_lib_dirs[0]) def get_name_and_dir_from_output_file_path( file_path: str, ) -> tuple[str, str]: """ This function help prepare parameters to new cpp_builder. Example: input_code: /tmp/tmpof1n5g7t/5c/c5crkkcdvhdxpktrmjxbqkqyq5hmxpqsfza4pxcf3mwk42lphygc.cpp name, dir = get_name_and_dir_from_output_file_path(input_code) Run result: name = c5crkkcdvhdxpktrmjxbqkqyq5hmxpqsfza4pxcf3mwk42lphygc dir = /tmp/tmpof1n5g7t/5c/ put 'name' and 'dir' to CppBuilder's 'name' and 'output_dir'. CppBuilder --> get_target_file_path will format output path accoding OS: Linux: /tmp/tmppu87g3mm/zh/czhwiz4z7ca7ep3qkxenxerfjxy42kehw6h5cjk6ven4qu4hql4i.so Windows: [Windows temp path]/tmppu87g3mm/zh/czhwiz4z7ca7ep3qkxenxerfjxy42kehw6h5cjk6ven4qu4hql4i.dll """ name_and_ext = os.path.basename(file_path) name, _ext = os.path.splitext(name_and_ext) dir = os.path.dirname(file_path) return name, dir class CppBuilder: """ CppBuilder is a cpp jit builder, and it supports both Windows, Linux and MacOS. Args: name: 1. Build target name, the final target file will append extension type automatically. 2. Due to the CppBuilder is supports mutliple OS, it will maintains ext for OS difference. sources: Source code file list to be built. BuildOption: Build options to the builder. output_dir: 1. The output_dir the taget file will output to. 2. The default value is empty string, and then the use current dir as output dir. 3. Final target file: output_dir/name.ext """ def __get_python_module_ext(self) -> str: SHARED_LIB_EXT = ".pyd" if _IS_WINDOWS else ".so" return SHARED_LIB_EXT def __get_object_ext(self) -> str: EXT = ".obj" if _IS_WINDOWS else ".o" return EXT def __init__( self, name: str, sources: Union[str, list[str]], BuildOption: BuildOptionsBase, output_dir: str = "", ) -> None: self._compiler = "" self._cflags_args = "" self._definitions_args = "" self._include_dirs_args = "" self._ldflags_args = "" self._libraries_dirs_args = "" self._libraries_args = "" self._passthrough_parameters_args = "" # When relative path is used, we need to maintain the source dir list. self._orig_source_paths = [] self._output_dir = "" self._target_file = "" self._use_relative_path: bool = False self._aot_mode: bool = False self._name = name # Code start here, initial self internal veriables firstly. self._build_option = BuildOption self._compiler = BuildOption.get_compiler() self._use_relative_path = BuildOption.get_use_relative_path() self._aot_mode = BuildOption.get_aot_mode() self._output_dir = output_dir self._compile_only = BuildOption.get_compile_only() file_ext = ( self.__get_object_ext() if self._compile_only else self.__get_python_module_ext() ) self._target_file = os.path.join(self._output_dir, f"{self._name}{file_ext}") if isinstance(sources, str): sources = [sources] if config.is_fbcode(): if self._aot_mode and not self._use_relative_path: inp_name = sources else: # Will create another temp director for building, so do NOT use # use the absolute path. inp_name = [os.path.basename(i) for i in sources] self._orig_source_paths = sources self._sources_args = " ".join(inp_name) else: self._sources_args = " ".join(sources) for cflag in BuildOption.get_cflags(): if _IS_WINDOWS: self._cflags_args += f"/{cflag} " else: self._cflags_args += f"-{cflag} " for definition in BuildOption.get_definitions(): if _IS_WINDOWS: self._definitions_args += f"/D {definition} " else: self._definitions_args += f"-D {definition} " for inc_dir in BuildOption.get_include_dirs(): if _IS_WINDOWS: self._include_dirs_args += f'/I "{inc_dir}" ' else: self._include_dirs_args += f"-I{inc_dir} " for ldflag in BuildOption.get_ldflags(): if _IS_WINDOWS: self._ldflags_args += f"/{ldflag} " else: self._ldflags_args += f"-{ldflag} " for lib_dir in BuildOption.get_libraries_dirs(): if _IS_WINDOWS: self._libraries_dirs_args += f'/LIBPATH:"{lib_dir}" ' else: self._libraries_dirs_args += f"-L{lib_dir} " for lib in BuildOption.get_libraries(): if _IS_WINDOWS: self._libraries_args += f'"{lib}.lib" ' else: self._libraries_args += f"-l{lib} " for passthrough_arg in BuildOption.get_passthrough_args(): self._passthrough_parameters_args += f"{passthrough_arg} " def get_command_line(self) -> str: def format_build_command( compiler: str, sources: str, include_dirs_args: str, definitions_args: str, cflags_args: str, ldflags_args: str, libraries_args: str, libraries_dirs_args: str, passthrough_args: str, target_file: str, ) -> str: if _IS_WINDOWS: # https://learn.microsoft.com/en-us/cpp/build/walkthrough-compile-a-c-program-on-the-command-line?view=msvc-1704 # https://stackoverflow.com/a/31566153 cmd = ( f"{compiler} {include_dirs_args} {definitions_args} {cflags_args} {sources} " f"{passthrough_args} /LD /Fe{target_file} /link {libraries_dirs_args} {libraries_args} {ldflags_args} " ) cmd = normalize_path_separator(cmd) else: compile_only_arg = "-c" if self._compile_only else "" cmd = re.sub( r"[ \n]+", " ", f""" {compiler} {sources} {definitions_args} {cflags_args} {include_dirs_args} {passthrough_args} {ldflags_args} {libraries_args} {libraries_dirs_args} {compile_only_arg} -o {target_file} """, ).strip() return cmd command_line = format_build_command( compiler=self._compiler, sources=self._sources_args, include_dirs_args=self._include_dirs_args, definitions_args=self._definitions_args, cflags_args=self._cflags_args, ldflags_args=self._ldflags_args, libraries_args=self._libraries_args, libraries_dirs_args=self._libraries_dirs_args, passthrough_args=self._passthrough_parameters_args, target_file=os.path.basename(self._target_file) if self._use_relative_path else self._target_file, ) return command_line def get_target_file_path(self) -> str: return normalize_path_separator(self._target_file) def build_fbcode_re( self, ) -> None: from torch._inductor.codecache import cpp_prefix_path with dynamo_timed("compile_file"): command = self.get_command_line().split() try: # Need to copy our header into the same folder as the sourcecode. header_path = cpp_prefix_path() header_name = os.path.basename(header_path) output_path = self._target_file # When we build remotely, we need to make sure to carefully copy any files # that are required during the compilation process into our build directly. # This is where all of the ATen/c10/Torch includes come from. torch_includes_path = os.path.join(_TORCH_PATH, "include") with tempfile.TemporaryDirectory() as tmp_dir: # Copy everything to tmp compilation folder shutil.copy(header_path, os.path.join(tmp_dir, header_name)) shutil.copy(_LINKER_SCRIPT, os.path.join(tmp_dir, "script.ld")) for src in self._orig_source_paths: shutil.copy(src, os.path.join(tmp_dir, os.path.basename(src))) dest_include_path = os.path.join(tmp_dir, "include") shutil.copytree(torch_includes_path, dest_include_path) # Run the build tmp_output_path = _run_build_command( command, tmp_dir, os.path.basename(output_path) ) # Copy output from the build if os.path.exists(output_path): os.remove(output_path) shutil.copy(tmp_output_path, output_path) if output_path.endswith(".o"): os.chmod(output_path, 0o644) elif output_path.endswith(".so"): os.chmod(output_path, 0o755) except subprocess.CalledProcessError as e: output = e.output.decode("utf-8") raise exc.CppCompileError(command, output) from e def build(self) -> None: """ It is must need a temperary directory to store object files in Windows. After build completed, delete the temperary directory to save disk space. """ if self._use_relative_path: # remote build uses relative path return self.build_fbcode_re() _create_if_dir_not_exist(self._output_dir) _build_tmp_dir = os.path.join( self._output_dir, f"{self._name}_{_BUILD_TEMP_DIR}" ) _create_if_dir_not_exist(_build_tmp_dir) build_cmd = self.get_command_line() run_compile_cmd(build_cmd, cwd=_build_tmp_dir) _remove_dir(_build_tmp_dir) def save_compile_cmd_to_cmake( self, cmake_path: str, ) -> None: definitions = " ".join(self._build_option.get_definitions()) contents = textwrap.dedent( f""" cmake_minimum_required(VERSION 3.18 FATAL_ERROR) project(aoti_model LANGUAGES CXX) set(CMAKE_CXX_STANDARD 17) # May need to point CMAKE_PREFIX_PATH to the right torch location find_package(Torch REQUIRED) # Set a shared library target add_library(aoti_model SHARED) # Add macro definitions target_compile_definitions(aoti_model PRIVATE {definitions}) # Add compile flags target_compile_options(aoti_model PRIVATE {self._cflags_args}) # Backend specific flags target_compile_options(aoti_model PRIVATE {self._passthrough_parameters_args} -c) """ ) with open(cmake_path, "w") as f: f.write(contents) def save_src_to_cmake(self, cmake_path: str, src_path: str) -> None: # Remove the directory part of file_path src_path = "${CMAKE_CURRENT_SOURCE_DIR}/" + Path(src_path).name with open(cmake_path, "a") as f: f.write(f"target_sources(aoti_model PRIVATE {src_path})\n") def save_link_cmd_to_cmake(self, cmake_path: str) -> None: lflags = " ".join(self._build_option.get_ldflags()) libs = " ".join(self._build_option.get_libraries()) contents = textwrap.dedent( f""" # Add linker flags target_link_options(aoti_model PRIVATE {lflags}) # Add libraries target_link_libraries(aoti_model PRIVATE {libs}) """ ) assert os.path.exists(cmake_path), ( f"save_link_cmd_to_cmakefile expects {cmake_path} to already exist" ) with open(cmake_path, "a") as f: f.write(contents)