Update top-level Python project for CMake compatibility.

This commit reimplements the (no longer recommended) setuptools based
build system using a standards-based in-tree PEP517 build backend.
The implementation is partially based on
  https://codeberg.org/ziglang/zig-pypi/src/branch/main/make_wheels.py
which is licensed under BSD-0-clause.

It also adds a new option `YOSYS_BUILD_PYTHON_ONLY` that is available
only if the binary or the library aren't going to be installed, which
turns off these targets entirely, as well as some dependent ones
(e.g. tests).

Co-authored-by: Mohamed Gaber <me@donn.website>

pyosys/CMakeLists.txt

@@ -24,6 +24,6 @@ yosys_core(pyosys
 	INCLUDE_DIRS
 		${pybind11_INCLUDE_DIR}
 	LIBRARIES
-		$<${YOSYS_ENABLE_PYTHON}:Python3::Python>
+		$<${YOSYS_ENABLE_PYTHON}:Python3::Module>
 	ESSENTIAL
 )

pyosys/build/local_backend.py

@@ -0,0 +1,175 @@
+# To build a wheel with additional CMake options, use `--build-option`, e.g.:
+#
+# 	python -m build -w -Ccmake=-DYOSYS_COMPILER_LAUNCHER=ccache
+#   pip install -Ccmake=-DYOSYS_COMPILER_LAUNCHER=ccache .
+
+import re
+import os
+import sys
+import pathlib
+import tarfile
+import tempfile
+import subprocess
+import sysconfig
+from email.policy import EmailPolicy
+from email.message import EmailMessage
+from wheel.wheelfile import WheelFile
+
+
+PROJECT_NAME = "pyosys"
+PROJECT_VERSION = subprocess.check_output([
+	"cmake",
+	f"-DCMAKE_SOURCE_DIR={os.getcwd()}",
+	"-P", "cmake/GetPyosysVersion.cmake"
+], encoding="ascii").strip()
+DIST_NAME = f"{PROJECT_NAME}-{PROJECT_VERSION}"
+
+
+# https://packaging.python.org/en/latest/specifications/platform-compatibility-tags/
+if sys.implementation.name == "cpython":
+	PYTHON_TAG = f"cp{sysconfig.get_config_var('py_version_nodot')}"
+	# freethreaded builds have an ABI flag appended, "t"
+	ABI_TAG = f"cp{sysconfig.get_config_var('py_version_nodot')}{sysconfig.get_config_var('abiflags')}"
+else:
+	raise NotImplementedError("unsupported Python implementation")
+# get_platform() always returns the MACOSX_DEPLOYMENT_TARGET this intepreter is
+# configured with:
+# 	https://github.com/python/cpython/blob/494f2e3c92cc1b7774cca16fca5c7d1ff18c0de2/Lib/_osx_support.py#L504
+PLATFORM_TAG_RAW = sysconfig.get_platform()
+MACOSX_DEPLOYMENT_TARGET_FLAGS = []
+if interpreter_deployment_target := sysconfig.get_config_var("MACOSX_DEPLOYMENT_TARGET"):
+	cmake_deployment_target = interpreter_deployment_target
+	interpreter_deployment_target = tuple(int(v) for v in interpreter_deployment_target.split("."))
+	# Yosys fails to compile for anything below 10.15 because of std::filesystem
+	requested_deployment_target = tuple(int(v) for v in os.environ.get("MACOSX_DEPLOYMENT_TARGET", "10.15").split("."))
+	if requested_deployment_target > interpreter_deployment_target:
+		resolved_platform_version_string = ".".join(str(v) for v in requested_deployment_target)
+		cmake_deployment_target = resolved_platform_version_string
+		if "." not in resolved_platform_version_string:
+			# macOS 11+ need to be "bare" for MACOSX_DEPLOYMENT_TARGET but have
+			# the .0 for Python platform versions
+			resolved_platform_version_string += ".0"
+		PLATFORM_TAG_RAW = re.sub(r"(macosx)-\d+\.\d+", rf"\1-{resolved_platform_version_string}", PLATFORM_TAG_RAW)
+	MACOSX_DEPLOYMENT_TARGET_FLAGS = [f"-DCMAKE_OSX_DEPLOYMENT_TARGET={cmake_deployment_target}"]
+# Source for these substitutions:
+# 	https://github.com/pypa/wheel/blob/197012dcb8a9da10570d6486bc1a70305861e7f2/src/wheel/_bdist_wheel.py#L351
+PLATFORM_TAG = PLATFORM_TAG_RAW.lower().replace("-", "_").replace(".", "_").replace(" ", "_")
+COMPAT_TAG = f"{PYTHON_TAG}-{ABI_TAG}-{PLATFORM_TAG}"
+
+
+def compile_pyosys(cmake_options=[], parallel=os.cpu_count() or 1):
+	install_dir = tempfile.TemporaryDirectory(prefix="pyosys_install")
+	with tempfile.TemporaryDirectory(prefix="pyosys_build") as build_dir:
+		subprocess.check_call([
+			"cmake",
+			"-S", ".",
+			"-B", build_dir,
+			"-DCMAKE_BUILD_TYPE=Release",
+			f"-DPython3_EXECUTABLE={sys.executable}",
+			"-DYOSYS_WITH_PYTHON=ON",
+			"-DYOSYS_INSTALL_DRIVER=OFF",
+			"-DYOSYS_INSTALL_LIBRARY=OFF",
+			"-DYOSYS_INSTALL_PYTHON=ON",
+			f"-DCMAKE_INSTALL_PREFIX={install_dir.name}",
+			f"-DYOSYS_INSTALL_PYTHON_SITEDIR=python",
+			"-DYOSYS_BUILD_PYTHON_ONLY=ON",
+			*cmake_options,
+			*MACOSX_DEPLOYMENT_TARGET_FLAGS,
+		])
+		subprocess.check_call([
+			"cmake",
+			"--build", build_dir,
+			"-t", "pyosys",
+			f"-j{parallel}",
+		])
+		subprocess.check_call([
+			"cmake",
+			"--install", build_dir,
+			"--strip",
+		])
+	return install_dir
+
+
+def make_message(headers, payload=None):
+	msg = EmailMessage(policy=EmailPolicy(max_line_length=0))
+	for name, value in headers:
+		if isinstance(value, list):
+			for value_part in value:
+				msg[name] = value_part
+		else:
+			msg[name] = value
+	if payload:
+		msg.set_payload(payload)
+	return bytes(msg)
+
+
+def build_sdist(sdist_dir, config_settings=None):
+	sdist_filename = f"{DIST_NAME}.tar.gz"
+
+	with tarfile.open(pathlib.Path(sdist_dir) / sdist_filename, "w:gz",
+			format=tarfile.PAX_FORMAT) as sdist:
+		def exclude_build(entry):
+			name = entry.name.removeprefix(f"{DIST_NAME}/")
+			if name in (".cache", "build", "dist"):
+				return
+			if os.path.basename(name) in (".git", "__pycache__"):
+				return
+			return entry
+		sdist.add(os.getcwd(), arcname=DIST_NAME, filter=exclude_build)
+
+	return sdist_filename
+
+
+def get_metadata_files():
+	with open("README.md", "rb") as readme:
+		long_description = readme.read()
+
+	return {
+		"WHEEL": make_message([
+			("Wheel-Version", "1.0"),
+			("Generator", "pyosys build backend"),
+			("Root-Is-Purelib", "false"),
+			("Tag", [COMPAT_TAG]),
+		]),
+		"METADATA": make_message([
+			("Metadata-Version", "2.4"),
+			("Name", PROJECT_NAME),
+			("Version", PROJECT_VERSION),
+			("Summary", "Python access to libyosys"),
+			("Description-Content-Type", "text/markdown"),
+			("License-Expression", "MIT"),
+			("Classifier", "Programming Language :: Python :: 3"),
+			("Classifier", "Intended Audience :: Developers"),
+			("Classifier", "Operating System :: POSIX :: Linux"),
+			("Classifier", "Operating System :: MacOS :: MacOS X"),
+			("Requires-Python", ">=3.10"),
+		], long_description)
+	}
+
+
+def prepare_metadata_for_build_wheel(metadata_directory, config_settings=None):
+	os.mkdir(f"{metadata_directory}/{DIST_NAME}.dist-info")
+
+	for filename, contents in get_metadata_files().items():
+		with open(f"{metadata_directory}/{DIST_NAME}.dist-info/{filename}", "wb") as f:
+			f.write(contents)
+
+	return f"{DIST_NAME}.dist-info"
+
+
+def build_wheel(wheel_dir, config_settings=None, metadata_directory=None):
+	wheel_filename = f"{DIST_NAME}-{COMPAT_TAG}.whl"
+
+	with WheelFile(pathlib.Path(wheel_dir) / wheel_filename, "w") as wheel:
+		for filename, contents in get_metadata_files().items():
+			wheel.writestr(f"{DIST_NAME}.dist-info/{filename}", contents)
+
+		cmake_options = []
+		if config_settings is not None:
+			if cmake_options := config_settings.get("cmake", cmake_options):
+				if isinstance(cmake_options, str):
+					cmake_options = [cmake_options]
+		with compile_pyosys(cmake_options) as install_dir:
+			wheel.write_files(pathlib.Path(install_dir) / "python")
+
+	return wheel_filename

pyosys/hashlib.h

@@ -482,9 +482,11 @@ void bind_idict(module &m, const char *name_cstr) {
 			return make_iterator(s.begin(), s.end());
 		})
 		.def("values", [](args _){
+			(void)_;
 			throw type_error("idicts do not support iteration on the integers");
 		})
 		.def("items", [](args _){
+			(void)_;
 			throw type_error("idicts do not support pairwise iteration");
 		})
 		.def("update", [](C &s, iterable other) {
@@ -521,6 +523,7 @@ void bind_idict(module &m, const char *name_cstr) {
 
 	for (const char *mutator: {"__setitem__", "__delitem__", "pop", "popitem", "setdefault"}) {
 		cls.def(mutator, [](args _) {
+			(void)_;
 			throw type_error("idicts do not support arbitrary element mutation");
 		});
 	}