Allow to set native stack boundary to exec_env

core/iwasm/common/wasm_exec_env.c

@@ -282,8 +282,13 @@ wasm_exec_env_set_thread_info(WASMExecEnv *exec_env)
     os_mutex_lock(&exec_env->wait_lock);
 #endif
     exec_env->handle = os_self_thread();
-    exec_env->native_stack_boundary =
-        stack_boundary ? stack_boundary + WASM_STACK_GUARD_SIZE : NULL;
+    if (exec_env->user_native_stack_boundary)
+        /* WASM_STACK_GUARD_SIZE isn't added for flexibility to developer,
+           he must ensure that enough guard bytes are kept. */
+        exec_env->native_stack_boundary = exec_env->user_native_stack_boundary;
+    else
+        exec_env->native_stack_boundary =
+            stack_boundary ? stack_boundary + WASM_STACK_GUARD_SIZE : NULL;
     exec_env->native_stack_top_min = (void *)UINTPTR_MAX;
 #if WASM_ENABLE_THREAD_MGR != 0
     os_mutex_unlock(&exec_env->wait_lock);

core/iwasm/common/wasm_exec_env.h

@@ -136,6 +136,10 @@ typedef struct WASMExecEnv {
 
     void *user_data;
 
+    /* The boundary of native stack set by host embedder. It is used
+       if it is not NULL when calling wasm functions. */
+    uint8 *user_native_stack_boundary;
+
     /* The native thread handle of current thread */
     korp_tid handle;
 

core/iwasm/common/wasm_runtime_common.c

@@ -2225,6 +2225,13 @@ wasm_runtime_get_user_data(WASMExecEnv *exec_env)
     return exec_env->user_data;
 }
 
+void
+wasm_runtime_set_native_stack_boundary(WASMExecEnv *exec_env,
+                                       uint8 *native_stack_boundary)
+{
+    exec_env->user_native_stack_boundary = native_stack_boundary;
+}
+
 #ifdef OS_ENABLE_HW_BOUND_CHECK
 void
 wasm_runtime_access_exce_check_guard_page()

core/iwasm/common/wasm_runtime_common.h

@@ -673,6 +673,11 @@ wasm_runtime_set_user_data(WASMExecEnv *exec_env, void *user_data);
 WASM_RUNTIME_API_EXTERN void *
 wasm_runtime_get_user_data(WASMExecEnv *exec_env);
 
+/* See wasm_export.h for description */
+WASM_RUNTIME_API_EXTERN void
+wasm_runtime_set_native_stack_boundary(WASMExecEnv *exec_env,
+                                       uint8 *native_stack_boundary);
+
 #if WASM_CONFIGURABLE_BOUNDS_CHECKS != 0
 /* See wasm_export.h for description */
 WASM_RUNTIME_API_EXTERN void

core/iwasm/include/wasm_export.h

@@ -1755,6 +1755,26 @@ wasm_runtime_set_user_data(wasm_exec_env_t exec_env, void *user_data);
 WASM_RUNTIME_API_EXTERN void *
 wasm_runtime_get_user_data(wasm_exec_env_t exec_env);
 
+/**
+ * Set native stack boundary to execution environment, if it is set,
+ * it will be used instead of getting the boundary with the platform
+ * layer API when calling wasm functions. This is useful for some
+ * fiber cases.
+ *
+ * Note: unlike setting the boundary by runtime, this API doesn't add
+ * the WASM_STACK_GUARD_SIZE(see comments in core/config.h) to the
+ * exec_env's native_stack_boundary to reserve bytes to the native
+ * thread stack boundary, which is used to throw native stack overflow
+ * exception if the guard boundary is reached. Developer should ensure
+ * that enough guard bytes are kept.
+ *
+ * @param exec_env the execution environment
+ * @param native_stack_boundary the user data to be set
+ */
+WASM_RUNTIME_API_EXTERN void
+wasm_runtime_set_native_stack_boundary(wasm_exec_env_t exec_env,
+                                       uint8_t *native_stack_boundary);
+
 /**
  * Dump runtime memory consumption, including:
  *     Exec env memory consumption