Return error when exception was raised after main thread finishes (#2169)

Currently, if a thread is spawned and raises an exception after the main thread
has finished, iwasm returns with success instead of returning 1 (i.e. error).

Since wasm_runtime_get_wasi_exit_code waits for all threads to finish and only
returns the wasi exit code, this PR performs the exception check again and
returns error if an exception was raised.

core/iwasm/libraries/lib-wasi-threads/test/trap_after_main_thread_finishes.c

@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2023 Amazon.com Inc. or its affiliates. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#ifndef __wasi__
+#error This example only compiles to WASM/WASI target
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+
+#include "wasi_thread_start.h"
+
+enum CONSTANTS {
+    SECOND = 1000 * 1000 * 1000, /* 1 second */
+    TIMEOUT = 1LL * SECOND
+};
+
+typedef struct {
+    start_args_t base;
+} shared_t;
+
+void
+__wasi_thread_start_C(int thread_id, int *start_arg)
+{
+    /* Wait so that the exception is raised after the main thread has finished
+     * already */
+    __builtin_wasm_memory_atomic_wait32(NULL, 0, TIMEOUT);
+    __builtin_trap();
+}
+
+int
+main(int argc, char **argv)
+{
+    shared_t data = { 0 };
+
+    assert(start_args_init(&data.base));
+    int thread_id = __wasi_thread_spawn(&data);
+    assert(thread_id > 0 && "Thread creation failed");
+
+    return EXIT_SUCCESS;
+}

core/iwasm/libraries/lib-wasi-threads/test/trap_after_main_thread_finishes.json

@@ -0,0 +1,3 @@
+{
+  "exit_code": 1
+}

product-mini/platforms/posix/main.c

@@ -745,8 +745,12 @@ main(int argc, char *argv[])
 
 #if WASM_ENABLE_LIBC_WASI != 0
     if (ret == 0) {
-        /* propagate wasi exit code. */
+        /* wait for threads to finish and propagate wasi exit code. */
         ret = wasm_runtime_get_wasi_exit_code(wasm_module_inst);
+        if (wasm_runtime_get_exception(wasm_module_inst)) {
+            /* got an exception in spawned thread */
+            ret = 1;
+        }
     }
 #endif
 

product-mini/platforms/windows/main.c

@@ -549,8 +549,12 @@ main(int argc, char *argv[])
 
 #if WASM_ENABLE_LIBC_WASI != 0
     if (ret == 0) {
-        /* propagate wasi exit code. */
+        /* wait for threads to finish and propagate wasi exit code. */
         ret = wasm_runtime_get_wasi_exit_code(wasm_module_inst);
+        if (wasm_runtime_get_exception(wasm_module_inst)) {
+            /* got an exception in spawned thread */
+            ret = 1;
+        }
     }
 #endif