Initial commit.

This code has been extracted from yowasp-yosys. The part of it that
handles caching has been changed to keep the cached binaries for
every WebAssembly module digest around. This does waste some space,
but can save a lot of time e.g. when bisecting.

Author: whitequark

.gitignore

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+__pycache__/
+/*.egg-info
+/.eggs
+/build
+/dist

LICENSE.txt

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+ISC License
+
+Copyright (C) Catherine <whitequark@whitequark.org>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

README.md

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+YoWASP runtime
+==============
+
+This package is an internal support package for the [YoWASP project][yowasp]. It handles interfacing with the [WebAssembly][] runtime and the supported operating systems. Do not depend on this package in your own code.
+
+[webassembly]: https://webassembly.org/
+[yowasp]: https://yowasp.github.io/
+
+License
+-------
+
+This package is covered by the [ISC license](LICENSE.txt).

pyproject.toml

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+[build-system]
+requires = ["setuptools~=67.0"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "yowasp-runtime"
+version = "1.0"
+description = "Common runtime for YoWASP packages"
+readme = "README.md"
+authors = [{name = "Catherine", email = "whitequark@whitequark.org"}]
+license = {file = "LICENSE.txt"}
+classifiers = [
+	"License :: OSI Approved :: ISC License (ISCL)"
+]
+
+dependencies = [
+	"importlib_resources; python_version<'3.9'",
+	"appdirs~=1.4",
+	"wasmtime>=1.0,<2"
+]
+
+[project.urls]
+"Homepage" = "https://yowasp.org/"
+"Source Code" = "https://github.com/YoWASP/runtime"
+"Bug Tracker" = "https://github.com/YoWASP/runtime/issues"

yowasp_runtime/__init__.py

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+import os
+import sys
+import wasmtime
+import pathlib
+import hashlib
+import appdirs
+try:
+    from importlib import resources as importlib_resources
+    importlib_resources.files
+except (ImportError, AttributeError):
+    import importlib_resources
+
+
+def run_wasm(__package__, wasm_filename, *, resources, argv):
+    # load the WebAssembly application
+    module_binary = importlib_resources.read_binary(__package__, wasm_filename)
+    module_digest = hashlib.sha1(module_binary).hexdigest()
+
+    wasi_cfg = wasmtime.WasiConfig()
+
+    # inherit standard I/O handles
+    wasi_cfg.inherit_stdin()
+    wasi_cfg.inherit_stdout()
+    wasi_cfg.inherit_stderr()
+
+    # use provided argv
+    wasi_cfg.argv = argv
+
+    # preopens for package resources
+    for resource in resources:
+        wasi_cfg.preopen_dir(str(importlib_resources.files(__package__) / resource), 
+                             "/" + resource)
+
+    # preopens for absolute paths
+    if os.name == "nt":
+        for letter in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ":
+            wasi_cfg.preopen_dir(letter + ":\\", letter + ":")
+    else:
+        wasi_cfg.preopen_dir("/", "/")
+
+    # preopens for relative paths
+    wasi_cfg.preopen_dir(".", ".")
+    for level in range(len(pathlib.Path().cwd().parts)):
+        wasi_cfg.preopen_dir(str(pathlib.Path("").joinpath(*[".."] * level)),
+                             "/".join([".."] * level))
+
+    # compute path to cache
+    default_cache_path = appdirs.user_cache_dir("YoWASP", appauthor=False)
+    cache_path = pathlib.Path(os.getenv("YOWASP_CACHE_DIR", default_cache_path))
+    cache_filename = (cache_path / __package__ / wasm_filename / module_digest)
+
+    # compile WebAssembly to machine code, or load cached
+    engine = wasmtime.Engine()
+    if cache_filename.exists():
+        module = wasmtime.Module.deserialize_file(engine, str(cache_filename))
+    else:
+        print("Preparing to run {}. This might take a while...".format(argv[0]), file=sys.stderr)
+        module = wasmtime.Module(engine, module_binary)
+        cache_filename.parent.mkdir(parents=True, exist_ok=True)
+        with cache_filename.open("wb") as cache_file:
+            cache_file.write(module.serialize())
+
+    # run compiled code
+    linker = wasmtime.Linker(engine)
+    linker.define_wasi()
+    store = wasmtime.Store(engine)
+    store.set_wasi(wasi_cfg)
+    app = linker.instantiate(store, module)
+    linker.define_instance(store, "app", app)
+    try:
+        app.exports(store)["_start"](store)
+        return 0
+    except wasmtime.ExitTrap as trap:
+        return trap.code