WIP: add support for threads

tests/test_threads.py

@@ -0,0 +1,28 @@
+import unittest
+
+from wasmtime import *
+
+
+class TestThreads(unittest.TestCase):
+    def test_threads(self):
+        config = Config()
+        config.wasm_threads = True
+
+        engine = Engine(config)
+        linker = Linker(engine)
+        store = Store(engine)
+
+        linker.define_wasi()
+
+        wasi_config = WasiConfig()
+        wasi_config.argv = ['3']
+        wasi_config.inherit_argv()
+        wasi_config.inherit_stdout()
+        store.set_wasi(wasi_config)
+
+        module = Module.from_file(engine, 'tests/threads.wasm')
+        # linker.define_wasi_threads(store, module)
+        # instance = linker.instantiate(store, module)
+        # instance.exports(store)["_start"](store)
+
+

tests/threads.cxx

@@ -0,0 +1,47 @@
+// Demo CLI that creates threads and uses atomics.
+//
+// Compile with the wasi-sdk:
+//
+//   ${WASI_SDK_PATH}/bin/clang++ -pthread --target=wasm32-wasi-threads --sysroot=${WASI_SYSROOT} -matomics -Wl,--import-memory,--export-memory,--initial-memory=8388608,--max-memory=4294967296,--shared-memory -fno-exceptions -Os threads.cxx
+
+#include <sstream>
+#include <iostream>
+#include <atomic>
+#include <thread>
+#include <vector>
+
+
+int main(int argc, char * argv[])
+{
+  int num_threads = 4;
+  if (argc > 1)
+  {
+    num_threads = std::stoi(argv[1]);
+  }
+
+  std::vector<std::thread> threads;
+  threads.reserve(num_threads);
+
+  std::atomic<int> created_threads(0);
+
+  for (int i = 0; i < num_threads; ++i)
+  {
+    threads.emplace_back([i, &created_threads]()
+    {
+      created_threads++;
+    });
+  }
+
+  for (auto &t : threads)
+  {
+    t.join();
+  }
+
+  std::cout << "Created " << created_threads << " threads." << std::endl;
+
+  if (created_threads == num_threads)
+  {
+    return EXIT_SUCCESS;
+  }
+  return EXIT_FAILURE;
+}