Add wasm-c-api nested function calls sample (#652)

And enable to copy back the return value of wasm main function when calling wasm_application_execute_main, add license headers in wasm-c-api samples, fix several issues reported by klocwork.

core/iwasm/common/wasm_application.c

@@ -182,6 +182,10 @@ wasm_application_execute_main(WASMModuleInstanceCommon *module_inst,
 
     ret = wasm_runtime_create_exec_env_and_call_wasm(module_inst, func,
                                                      argc1, argv1);
+    if (ret && func_type->result_count > 0 && argc > 0 && argv)
+        /* copy the return value */
+        *(int*)argv = (int)argv1[0];
+
     if (argv_buf_offset)
         wasm_runtime_module_free(module_inst, argv_buf_offset);
     return ret;
@@ -669,4 +673,4 @@ fail:
     bh_assert(exception);
     os_printf("%s\n", exception);
     return false;
-}
+}

core/iwasm/include/wasm_export.h

@@ -495,7 +495,9 @@ wasm_runtime_call_wasm_v(wasm_exec_env_t exec_env,
  *
  * @param module_inst the WASM module instance
  * @param argc the number of arguments
- * @param argv the arguments array
+ * @param argv the arguments array, if the main function has return value,
+ *   *(int*)argv stores the return value of the called main function after
+ *   this function returns.
  *
  * @return true if the main function is called, false otherwise and exception
  *   will be thrown, the caller can call wasm_runtime_get_exception to get

samples/spawn-thread/src/main.c

@@ -26,6 +26,7 @@ void *thread(void* arg)
     func = wasm_runtime_lookup_function(module_inst, "sum", NULL);
     if (!func) {
         printf("failed to lookup function sum");
+        return NULL;
     }
     argv[0] = thread_arg->start;
     argv[1] = thread_arg->length;
@@ -49,6 +50,7 @@ void *wamr_thread_cb(wasm_exec_env_t exec_env, void *arg)
     func = wasm_runtime_lookup_function(module_inst, "sum", NULL);
     if (!func) {
         printf("failed to lookup function sum");
+        return NULL;
     }
     argv[0] = thread_arg->start;
     argv[1] = thread_arg->length;
@@ -66,7 +68,7 @@ int main(int argc, char *argv[])
 {
     char *wasm_file = "wasm-apps/test.wasm";
     uint8 *wasm_file_buf = NULL;
-    uint32 wasm_file_size, wasm_argv[2], i;
+    uint32 wasm_file_size, wasm_argv[2], i, threads_created;
     uint32 stack_size = 16 * 1024, heap_size = 16 * 1024;
     wasm_module_t wasm_module = NULL;
     wasm_module_inst_t wasm_module_inst = NULL;
@@ -123,6 +125,7 @@ int main(int argc, char *argv[])
     func = wasm_runtime_lookup_function(wasm_module_inst, "sum", NULL);
     if (!func) {
         printf("failed to lookup function sum");
+        goto fail5;
     }
     wasm_argv[0] = 0;
     wasm_argv[1] = THREAD_NUM * 10;
@@ -159,17 +162,20 @@ int main(int argc, char *argv[])
 
         if (0 != pthread_create(&tid[i], NULL, thread, &thread_arg[i])) {
             printf("failed to create thread.\n");
+            wasm_runtime_destroy_spawned_exec_env(new_exec_env);
             break;
         }
     }
 
+    threads_created = i;
+
     sum = 0;
     memset(result, 0, sizeof(uint32) * THREAD_NUM);
-    for (i = 0; i < THREAD_NUM; i++) {
+    for (i = 0; i < threads_created; i++) {
         pthread_join(tid[i], (void **)&result[i]);
         sum += result[i];
         /* destroy the spawned exec_env */
-        if (thread_arg[0].exec_env)
+        if (thread_arg[i].exec_env)
             wasm_runtime_destroy_spawned_exec_env(thread_arg[i].exec_env);
     }
 
@@ -191,15 +197,18 @@ int main(int argc, char *argv[])
         }
     }
 
+    threads_created = i;
+
     sum = 0;
     memset(result, 0, sizeof(uint32) * THREAD_NUM);
-    for (i = 0; i < THREAD_NUM; i++) {
+    for (i = 0; i < threads_created; i++) {
         wasm_runtime_join_thread(wasm_tid[i], (void**)&result[i]);
         sum += result[i];
         /* No need to destroy the spawned exec_env */
     }
     printf("[spwan_thread]sum result: %d\n", sum);
 
+fail5:
     wasm_runtime_destroy_exec_env(exec_env);
 
 fail4:
@@ -217,4 +226,5 @@ fail2:
 fail1:
     /* destroy runtime environment */
     wasm_runtime_destroy();
-}
+    return 0;
+}

samples/wasm-c-api/CMakeLists.txt

@@ -93,8 +93,7 @@ set(EXAMPLES
   global
   reflect
   trap
-  # multi # AOT/JIT return multiple values
-  # globalexportimport # AOT/JIT doesn't suppport MULTI_MODULE
+  callback_chain
 )
 
 foreach(EX ${EXAMPLES})

samples/wasm-c-api/src/callback.c

@@ -84,6 +84,7 @@ int main(int argc, const char* argv[]) {
   wasm_byte_vec_new_uninitialized(&binary, file_size);
   if (fread(binary.data, file_size, 1, file) != 1) {
     printf("> Error loading module!\n");
+    fclose(file);
     return 1;
   }
   fclose(file);

samples/wasm-c-api/src/callback_chain.c

@@ -0,0 +1,267 @@
+/*
+ * Copyright (C) 2019 Intel Corporation.  All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "wasm_c_api.h"
+
+#define own
+
+static const byte_t *
+get_memory_data(uint32_t offset, uint32_t length);
+
+static bool
+call_wasm_function(uint32_t export_id,
+                   const wasm_val_t *args,
+                   wasm_val_t *results,
+                   const char *name);
+
+/************************ IMPORTED FUNCTIONS **************************/
+
+// (nil) -> i32
+#define FUNCTION_TYPE_NIL_I32 wasm_functype_new_0_1(wasm_valtype_new_i32())
+// (i32, i32) -> nil
+#define FUNCTION_TYPE_I32X2_NIL                                               \
+    wasm_functype_new_1_1(wasm_valtype_new_i32(), wasm_valtype_new_i32())
+
+/* IMPORT FUNCTION LIST */
+#define IMPORT_FUNCTION_LIST(V)                                               \
+    V(get_pairs, 0, FUNCTION_TYPE_NIL_I32)                                    \
+    V(log, 1, FUNCTION_TYPE_I32X2_NIL)
+
+/* EXPORT FUNCTION LIST */
+#define EXPORT_FUNCTION_LIST(V)                                               \
+    V(on_start)                                                               \
+    V(on_stop)                                                                \
+    V(malloc)                                                                 \
+    V(free)
+
+enum EXPORT_ITEM_NAME {
+#define DEFINE_ENUM(name) e_##name,
+    EXPORT_FUNCTION_LIST(DEFINE_ENUM)
+#undef DEFINE_ENUM
+      e_MEMORY,
+};
+
+#define DEFINE_FUNCTION(name)                                                 \
+    wasm_trap_t *STUB_##name(const wasm_val_t args[], wasm_val_t results[])
+
+#define DEFINE_EMPTY_FUNCTION(name)                                           \
+    DEFINE_FUNCTION(name)                                                     \
+    {                                                                         \
+        printf("[WASM -> NATIVE] calling back %s\n", __FUNCTION__);           \
+        return NULL;                                                          \
+    }
+#undef DEFINE_EMPTY_FUNCTION
+
+DEFINE_FUNCTION(get_pairs)
+{
+    wasm_val_t ret[1] = { WASM_INIT_VAL };
+    call_wasm_function(e_malloc, (wasm_val_t[]){ WASM_I32_VAL(24) }, ret,
+                       "malloc");
+    return NULL;
+}
+
+DEFINE_FUNCTION(log)
+{
+    wasm_val_t offset = args[0];
+    wasm_val_t length = args[1];
+    const byte_t *data = NULL;
+
+    printf("[WASM -> NATIVE] calling back %s\n", __FUNCTION__);
+
+    if (offset.kind != WASM_I32 || length.kind != WASM_I32) {
+        printf("> Error value type!\n");
+    }
+
+    if (!(data = get_memory_data(offset.of.i32, length.of.i32))) {
+        return NULL;
+    }
+
+    if (data[length.of.i32]) {
+        printf("> Error terminated character\n");
+        return NULL;
+    }
+
+    printf("[WASM_LOG] %s\n", data);
+    return NULL;
+}
+
+static inline void
+create_import_function_list(wasm_store_t *store,
+                            const wasm_extern_t *import_function_list[])
+{
+#define IMPORT_FUNCTION_VARIABLE_NAME(name, ...)                              \
+    own wasm_func_t *function_##name = NULL;
+    IMPORT_FUNCTION_LIST(IMPORT_FUNCTION_VARIABLE_NAME)
+#undef IMPORT_FUNCTION_VARIABLE_NAME
+
+#define CREATE_WASM_FUNCTION(name, index, CREATE_FUNC_TYPE)                   \
+    {                                                                         \
+        own wasm_functype_t *type = CREATE_FUNC_TYPE;                         \
+        if (!(function_##name = wasm_func_new(store, type, STUB_##name))) {   \
+            printf("> Error creating new function\n");                        \
+        }                                                                     \
+        wasm_functype_delete(type);                                           \
+    }
+    IMPORT_FUNCTION_LIST(CREATE_WASM_FUNCTION)
+#undef CREATE_WASM_FUNCTION
+
+#define ADD_TO_FUNCTION_LIST(name, index, ...)                                \
+    import_function_list[index] = wasm_func_as_extern(function_##name);
+    IMPORT_FUNCTION_LIST(ADD_TO_FUNCTION_LIST)
+#undef CREATE_IMPORT_FUNCTION
+}
+
+/**********************************************************************/
+// all exportted wasm functions. check with "/opt/wabt/bin/wasm-objdump -x -j Export X.wasm"
+// -1: memory
+// 0-32: functions
+static own wasm_extern_vec_t exports = { 0 };
+
+static const byte_t *
+get_memory_data(uint32_t offset, uint32_t length)
+{
+    wasm_memory_t *memory;
+
+    if (!(memory = wasm_extern_as_memory(exports.data[e_MEMORY]))) {
+        return NULL;
+    }
+
+    byte_t *base = wasm_memory_data(memory);
+    size_t size = wasm_memory_data_size(memory);
+    if (!base || offset + length > size) {
+        return NULL;
+    }
+
+    printf("[NATIVE -> WASM] accessing the memory...\n");
+
+    return base + offset;
+}
+
+static bool
+call_wasm_function(uint32_t export_id,
+                   const wasm_val_t *args,
+                   wasm_val_t *results,
+                   const char *name)
+{
+    const wasm_func_t *function;
+    wasm_trap_t *trap;
+
+    printf("[NATIVE -> WASM] calling func %s...\n", name);
+
+    if (!(function = wasm_extern_as_func(exports.data[export_id]))) {
+        printf("> Error get export function %u\n", export_id);
+        return false;
+    }
+
+    if ((trap = wasm_func_call(function, args, results))) {
+        own wasm_message_t message = { 0 };
+        wasm_trap_message(trap, &message);
+
+        if (message.data) {
+            printf("> Error calling function %s\n", message.data);
+        }
+        else {
+            printf("> Error calling function");
+        }
+
+        wasm_name_delete(&message);
+        wasm_trap_delete(trap);
+        return false;
+    }
+    return true;
+}
+
+int
+main(int argc, const char *argv[])
+{
+    // Initialize.
+    printf("Initializing...\n");
+    wasm_engine_t *engine = wasm_engine_new();
+    wasm_store_t *store = wasm_store_new(engine);
+
+    // Load binary.
+    printf("Loading binary...\n");
+    FILE *file = fopen("callback_chain.wasm", "rb");
+    if (!file) {
+        printf("> Error loading module!\n");
+        return 1;
+    }
+    fseek(file, 0L, SEEK_END);
+    size_t file_size = ftell(file);
+    fseek(file, 0L, SEEK_SET);
+    wasm_byte_vec_t binary;
+    wasm_byte_vec_new_uninitialized(&binary, file_size);
+    if (fread(binary.data, file_size, 1, file) != 1) {
+        printf("> Error loading module!\n");
+        fclose(file);
+        return 1;
+    }
+    fclose(file);
+
+    // Compile.
+    printf("Compiling module...\n");
+    own wasm_module_t *module = wasm_module_new(store, &binary);
+    if (!module) {
+        printf("> Error compiling module!\n");
+        return 1;
+    }
+
+    wasm_byte_vec_delete(&binary);
+
+    // Instantiate.
+    printf("Instantiating module...\n");
+    const wasm_extern_t *imports[10] = { 0 };
+
+    // Create external functions.
+    printf("Creating callback...\n");
+    create_import_function_list(store, imports);
+
+    own wasm_instance_t *instance =
+      wasm_instance_new(store, module, imports, NULL);
+    if (!instance) {
+        printf("> Error instantiating module!\n");
+        return 1;
+    }
+
+    // Extract export.
+    printf("Extracting export...\n");
+    wasm_instance_exports(instance, &exports);
+    if (!exports.size) {
+        printf("> Error accessing exports!\n");
+        return 1;
+    }
+
+    wasm_module_delete(module);
+    wasm_instance_delete(instance);
+
+    // Call.
+    printf("Calling export...\n");
+
+    if (!call_wasm_function(e_on_start, NULL, NULL, "on_start")) {
+        printf("> Error calling on_start\n");
+        return 1;
+    }
+
+    if (!call_wasm_function(e_on_stop, NULL, NULL, "on_stop")) {
+        printf("> Error calling on_stop\n");
+        return 1;
+    }
+
+    wasm_extern_vec_delete(&exports);
+
+    // Shut down.
+    printf("Shutting down...\n");
+    wasm_store_delete(store);
+    wasm_engine_delete(engine);
+
+    // All done.
+    printf("Done.\n");
+    return 0;
+}

samples/wasm-c-api/src/callback_chain.wat

@@ -0,0 +1,32 @@
+;; Copyright (C) 2019 Intel Corporation.  All rights reserved.
+;; SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+(module
+  (func $get_pairs (import "" "get_pairs") (result i32))
+  (func $log (import"" "log") (param i32 i32))
+
+  (func $on_start (export "on_start")
+    (call $log (i32.const 0) (i32.const 9))
+    (call $get_pairs)
+    (drop)
+  )
+
+  (func $on_stop (export "on_stop")
+    (call $log (i32.const 9) (i32.const 8))
+  )
+
+  (func $malloc (export "malloc") (param i32) (result i32)
+    (call $log (i32.const 17) (i32.const 7))
+    (i32.const 64)
+  )
+
+  (func $free(export "free") (param i32)
+    (call $log (i32.const 24) (i32.const 5))
+  )
+
+  (memory (export "memory") 1)
+  (data (i32.const 0) "on_start")
+  (data (i32.const 9) "on_stop")
+  (data (i32.const 17) "malloc")
+  (data (i32.const 24) "free")
+)

samples/wasm-c-api/src/global.c

@@ -69,6 +69,7 @@ int main(int argc, const char* argv[]) {
   wasm_byte_vec_new_uninitialized(&binary, file_size);
   if (fread(binary.data, file_size, 1, file) != 1) {
     printf("> Error loading module!\n");
+    fclose(file);
     return 1;
   }
   fclose(file);

samples/wasm-c-api/src/globalexportimport-0.wat

@@ -1,3 +1,6 @@
+;; Copyright (C) 2019 Intel Corporation.  All rights reserved.
+;; SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
 (module
   (global $mut_f32_export (export "var f32") (mut f32) (f32.const 7))
   (func (export "get var f32 export") (result f32) (global.get $mut_f32_export))

samples/wasm-c-api/src/globalexportimport-1.wat

@@ -1,3 +1,6 @@
+;; Copyright (C) 2019 Intel Corporation.  All rights reserved.
+;; SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
 (module
   (global $mut_f32_import (export "var f32") (import "globalexportimport-0" "var f32") (mut f32))
   (func (export "get var f32 export") (import "globalexportimport-0" "get var f32 export") (result f32))

samples/wasm-c-api/src/globalexportimport.c

@@ -1,3 +1,8 @@
+/*
+ * Copyright (C) 2019 Intel Corporation.  All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -62,6 +67,7 @@ wasm_module_t * create_module_from_file(wasm_store_t* store, const char * filena
   wasm_byte_vec_new_uninitialized(&binary, file_size);
   if (fread(binary.data, file_size, 1, file) != 1) {
     printf("> Error loading module!\n");
+    fclose(file);
     return NULL;
   }
   // Compile.

samples/wasm-c-api/src/hello.c

@@ -41,6 +41,7 @@ int main(int argc, const char* argv[]) {
   wasm_byte_vec_new_uninitialized(&binary, file_size);
   if (fread(binary.data, file_size, 1, file) != 1) {
     printf("> Error loading module!\n");
+    fclose(file);
     return 1;
   }
   fclose(file);

samples/wasm-c-api/src/multi.c

@@ -59,6 +59,7 @@ int main(int argc, const char* argv[]) {
   wasm_byte_vec_new_uninitialized(&binary, file_size);
   if (fread(binary.data, file_size, 1, file) != 1) {
     printf("> Error loading module!\n");
+    fclose(file);
     return 1;
   }
   fclose(file);

samples/wasm-c-api/src/reflect.c

@@ -32,6 +32,12 @@ void print_valtype(const wasm_valtype_t* type) {
 
 void print_valtypes(const wasm_valtype_vec_t* types) {
   bool first = true;
+
+  if (!types) {
+    printf("> Error print a NULL valtype\n");
+    return;
+  }
+
   for (size_t i = 0; i < types->size; ++i) {
     if (first) {
       first = false;
@@ -43,6 +49,11 @@ void print_valtypes(const wasm_valtype_vec_t* types) {
 }
 
 void print_externtype(const wasm_externtype_t* type) {
+  if (!type) {
+    printf("> Error print a NULL externtype\n");
+    return;
+  }
+
   switch (wasm_externtype_kind(type)) {
     case WASM_EXTERN_FUNC: {
       const wasm_functype_t* functype =
@@ -78,6 +89,11 @@ void print_externtype(const wasm_externtype_t* type) {
 }
 
 void print_name(const wasm_name_t* name) {
+  if (!name) {
+    printf("> Error print a NULL name\n");
+    return;
+  }
+
   printf("\"%.*s\"", (int)name->size, name->data);
 }
 
@@ -106,6 +122,7 @@ int main(int argc, const char* argv[]) {
   wasm_byte_vec_new_uninitialized(&binary, file_size);
   if (fread(binary.data, file_size, 1, file) != 1) {
     printf("> Error loading module!\n");
+    fclose(file);
     return 1;
   }
   fclose(file);

samples/wasm-c-api/src/trap.c

@@ -43,6 +43,7 @@ int main(int argc, const char* argv[]) {
   wasm_byte_vec_new_uninitialized(&binary, file_size);
   if (fread(binary.data, file_size, 1, file) != 1) {
     printf("> Error loading module!\n");
+    fclose(file);
     return 1;
   }
   fclose(file);