tests/integration/runners.py

@@ -3,6 +3,7 @@ Runners to help run WebAssembly code on various interpreters
 """
 from typing import Any, Iterable, TextIO
 
+import ctypes
 import io
 import os
 import subprocess
@@ -10,6 +11,7 @@ import tempfile
 
 import pywasm.binary
 import wasm3
+import wasmtime
 
 from phasm.compiler import phasm_compile
 from phasm.parser import phasm_parse
@@ -191,6 +193,66 @@ class RunnerPywasm3(RunnerBase):
     def call(self, function: str, *args: Any) -> Any:
         return self.rtime.find_function(function)(*args)
 
+class RunnerWasmtime(RunnerBase):
+    """
+    Implements a runner for wasmtime
+
+    See https://pypi.org/project/wasmtime/
+    """
+    store: wasmtime.Store
+    module: wasmtime.Module
+    instance: wasmtime.Instance
+
+    def interpreter_setup(self) -> None:
+        self.store = wasmtime.Store()
+
+    def interpreter_load(self) -> None:
+        self.module = wasmtime.Module(self.store.engine, self.wasm_bin)
+        self.instance = wasmtime.Instance(self.store, self.module, [])
+
+    def interpreter_write_memory(self, offset: int, data: Iterable[int]) -> None:
+        exports = self.instance.exports(self.store)
+        memory = exports['memory']
+        assert isinstance(memory, wasmtime.Memory) # type hint
+
+        data_ptr = memory.data_ptr(self.store)
+        data_len = memory.data_len(self.store)
+
+        idx = offset
+        for byt in data:
+            assert idx < data_len
+            data_ptr[idx] = ctypes.c_ubyte(byt)
+            idx += 1
+
+    def interpreter_read_memory(self, offset: int, length: int) -> bytes:
+        exports = self.instance.exports(self.store)
+        memory = exports['memory']
+        assert isinstance(memory, wasmtime.Memory) # type hint
+
+        data_ptr = memory.data_ptr(self.store)
+        data_len = memory.data_len(self.store)
+
+        raw = ctypes.string_at(data_ptr, data_len)
+
+        return raw[offset:length]
+
+    def interpreter_dump_memory(self, textio: TextIO) -> None:
+        exports = self.instance.exports(self.store)
+        memory = exports['memory']
+        assert isinstance(memory, wasmtime.Memory) # type hint
+
+        data_ptr = memory.data_ptr(self.store)
+        data_len = memory.data_len(self.store)
+
+        _dump_memory(textio, ctypes.string_at(data_ptr, data_len))
+
+    def call(self, function: str, *args: Any) -> Any:
+        exports = self.instance.exports(self.store)
+        func = exports[function]
+        assert isinstance(func, wasmtime.Func)
+
+        return func(self.store, *args)
+
 def _dump_memory(textio: TextIO, mem: bytes) -> None:
     line_width = 16
 

tests/integration/test_stdlib_alloc.py

@@ -3,10 +3,10 @@ import sys
 import pytest
 
 from .helpers import DASHES
-from .runners import RunnerPywasm3
+from .runners import RunnerPywasm3 as Runner
 
-def setup_interpreter(phash_code: str) -> RunnerPywasm3:
-    runner = RunnerPywasm3(phash_code)
+def setup_interpreter(phash_code: str) -> Runner:
+    runner = Runner(phash_code)
 
     runner.parse()
     runner.compile_ast()