Enable dump call stack to a buffer (#1244)

Enable dump call stack to a buffer, use API
`wasm_runtime_get_call_stack_buf_size` to get the required buffer size
and use API
`wasm_runtime_dump_call_stack_to_buf` to dump call stack to a buffer

core/iwasm/aot/aot_runtime.c

@@ -1511,7 +1511,9 @@ aot_call_function(WASMExecEnv *exec_env, AOTFunctionInstance *function,
 
 #if WASM_ENABLE_DUMP_CALL_STACK != 0
         if (!ret) {
-            aot_dump_call_stack(exec_env);
+            if (aot_create_call_stack(exec_env)) {
+                aot_dump_call_stack(exec_env, true, NULL, 0);
+            }
         }
 #endif
 
@@ -1568,7 +1570,9 @@ aot_call_function(WASMExecEnv *exec_env, AOTFunctionInstance *function,
 
 #if WASM_ENABLE_DUMP_CALL_STACK != 0
         if (aot_get_exception(module_inst)) {
-            aot_dump_call_stack(exec_env);
+            if (aot_create_call_stack(exec_env)) {
+                aot_dump_call_stack(exec_env, true, NULL, 0);
+            }
         }
 #endif
 
@@ -3018,38 +3022,24 @@ aot_free_frame(WASMExecEnv *exec_env)
                  || (WASM_ENABLE_PERF_PROFILING != 0) */
 
 #if WASM_ENABLE_DUMP_CALL_STACK != 0
-void
+bool
-aot_dump_call_stack(WASMExecEnv *exec_env)
+aot_create_call_stack(struct WASMExecEnv *exec_env)
 {
     AOTFrame *cur_frame = (AOTFrame *)exec_env->cur_frame,
              *first_frame = cur_frame;
     AOTModuleInstance *module_inst = (AOTModuleInstance *)exec_env->module_inst;
-    const char *func_name;
     uint32 n = 0;
 
-    os_printf("\n");
     while (cur_frame) {
-        func_name =
-            get_func_name_from_index(module_inst, cur_frame->func_index);
-
-        /* function name not exported, print number instead */
-        if (func_name == NULL) {
-            os_printf("#%02d $f%d \n", n, cur_frame->func_index);
-        }
-        else {
-            os_printf("#%02d %s \n", n, func_name);
-        }
-
         cur_frame = cur_frame->prev_frame;
         n++;
     }
-    os_printf("\n");
 
     /* release previous stack frames and create new ones */
     if (!bh_vector_destroy(module_inst->frames.ptr)
         || !bh_vector_init(module_inst->frames.ptr, n, sizeof(WASMCApiFrame),
                            false)) {
-        return;
+        return false;
     }
 
     cur_frame = first_frame;
@@ -3059,14 +3049,85 @@ aot_dump_call_stack(WASMExecEnv *exec_env)
         frame.module_offset = 0;
         frame.func_index = cur_frame->func_index;
         frame.func_offset = 0;
+        frame.func_name_wp =
+            get_func_name_from_index(module_inst, cur_frame->func_index);
 
         if (!bh_vector_append(module_inst->frames.ptr, &frame)) {
             bh_vector_destroy(module_inst->frames.ptr);
-            return;
+            return false;
         }
 
         cur_frame = cur_frame->prev_frame;
     }
+
+    return true;
+}
+
+#define PRINT_OR_DUMP()                                                   \
+    do {                                                                  \
+        total_len +=                                                      \
+            wasm_runtime_dump_line_buf_impl(line_buf, print, &buf, &len); \
+        if ((!print) && buf && (len == 0)) {                              \
+            return total_len;                                             \
+        }                                                                 \
+    } while (0)
+
+uint32
+aot_dump_call_stack(WASMExecEnv *exec_env, bool print, char *buf, uint32 len)
+{
+    AOTModuleInstance *module_inst = (AOTModuleInstance *)exec_env->module_inst;
+    uint32 n = 0, total_len = 0, total_frames;
+    /* reserve 256 bytes for line buffer, any line longer than 256 bytes
+     * will be truncated */
+    char line_buf[256];
+
+    if (!module_inst->frames.ptr) {
+        return 0;
+    }
+
+    total_frames = bh_vector_size(module_inst->frames.ptr);
+    if (total_frames == 0) {
+        return 0;
+    }
+
+    snprintf(line_buf, sizeof(line_buf), "\n");
+    PRINT_OR_DUMP();
+
+    while (n < total_frames) {
+        WASMCApiFrame frame = { 0 };
+        uint32 line_length, i;
+
+        if (!bh_vector_get(module_inst->frames.ptr, n, &frame)) {
+            return 0;
+        }
+
+        /* function name not exported, print number instead */
+        if (frame.func_name_wp == NULL) {
+            line_length = snprintf(line_buf, sizeof(line_buf), "#%02d $f%d\n",
+                                   n, frame.func_index);
+        }
+        else {
+            line_length = snprintf(line_buf, sizeof(line_buf), "#%02d %s\n", n,
+                                   frame.func_name_wp);
+        }
+
+        if (line_length >= sizeof(line_buf)) {
+            uint32 line_buffer_len = sizeof(line_buf);
+            /* If line too long, ensure the last character is '\n' */
+            for (i = line_buffer_len - 5; i < line_buffer_len - 2; i++) {
+                line_buf[i] = '.';
+            }
+            line_buf[line_buffer_len - 2] = '\n';
+        }
+
+        PRINT_OR_DUMP();
+
+        n++;
+    }
+    snprintf(line_buf, sizeof(line_buf), "\n");
+    PRINT_OR_DUMP();
+
+    return total_len + 1;
 }
 #endif /* end of WASM_ENABLE_DUMP_CALL_STACK */
 

core/iwasm/aot/aot_runtime.h

@@ -731,8 +731,24 @@ aot_alloc_frame(WASMExecEnv *exec_env, uint32 func_index);
 void
 aot_free_frame(WASMExecEnv *exec_env);
 
-void
+bool
-aot_dump_call_stack(WASMExecEnv *exec_env);
+aot_create_call_stack(struct WASMExecEnv *exec_env);
+
+/**
+ * @brief Dump wasm call stack or get the size
+ *
+ * @param exec_env the execution environment
+ * @param print whether to print to stdout or not
+ * @param buf buffer to store the dumped content
+ * @param len length of the buffer
+ *
+ * @return when print is true, return the bytes printed out to stdout; when
+ * print is false and buf is NULL, return the size required to store the
+ * callstack content; when print is false and buf is not NULL, return the size
+ * dumped to the buffer, 0 means error and data in buf may be invalid
+ */
+uint32
+aot_dump_call_stack(WASMExecEnv *exec_env, bool print, char *buf, uint32 len);
 
 void
 aot_dump_perf_profiling(const AOTModuleInstance *module_inst);

core/iwasm/common/wasm_runtime_common.c

@@ -4527,6 +4527,30 @@ wasm_externref_retain(uint32 externref_idx)
 #endif /* end of WASM_ENABLE_REF_TYPES */
 
 #if WASM_ENABLE_DUMP_CALL_STACK != 0
+uint32
+wasm_runtime_dump_line_buf_impl(const char *line_buf, bool dump_or_print,
+                                char **buf, uint32 *len)
+{
+    if (dump_or_print) {
+        return (uint32)os_printf("%s", line_buf);
+    }
+    else if (*buf) {
+        uint32 dump_len;
+
+        dump_len = snprintf(*buf, *len, "%s", line_buf);
+        if (dump_len >= *len) {
+            dump_len = *len;
+        }
+
+        *len = *len - dump_len;
+        *buf = *buf + dump_len;
+        return dump_len;
+    }
+    else {
+        return strlen(line_buf);
+    }
+}
+
 void
 wasm_runtime_dump_call_stack(WASMExecEnv *exec_env)
 {
@@ -4534,15 +4558,56 @@ wasm_runtime_dump_call_stack(WASMExecEnv *exec_env)
         wasm_exec_env_get_module_inst(exec_env);
 #if WASM_ENABLE_INTERP != 0
     if (module_inst->module_type == Wasm_Module_Bytecode) {
-        wasm_interp_dump_call_stack(exec_env);
+        wasm_interp_dump_call_stack(exec_env, true, NULL, 0);
     }
 #endif
 #if WASM_ENABLE_AOT != 0
     if (module_inst->module_type == Wasm_Module_AoT) {
-        aot_dump_call_stack(exec_env);
+        aot_dump_call_stack(exec_env, true, NULL, 0);
     }
 #endif
 }
+
+uint32
+wasm_runtime_get_call_stack_buf_size(wasm_exec_env_t exec_env)
+{
+    WASMModuleInstanceCommon *module_inst =
+        wasm_exec_env_get_module_inst(exec_env);
+
+#if WASM_ENABLE_INTERP != 0
+    if (module_inst->module_type == Wasm_Module_Bytecode) {
+        return wasm_interp_dump_call_stack(exec_env, false, NULL, 0);
+    }
+#endif
+#if WASM_ENABLE_AOT != 0
+    if (module_inst->module_type == Wasm_Module_AoT) {
+        return aot_dump_call_stack(exec_env, false, NULL, 0);
+    }
+#endif
+
+    return 0;
+}
+
+uint32
+wasm_runtime_dump_call_stack_to_buf(wasm_exec_env_t exec_env, char *buf,
+                                    uint32 len)
+{
+    WASMModuleInstanceCommon *module_inst =
+        wasm_exec_env_get_module_inst(exec_env);
+
+#if WASM_ENABLE_INTERP != 0
+    if (module_inst->module_type == Wasm_Module_Bytecode) {
+        return wasm_interp_dump_call_stack(exec_env, false, buf, len);
+    }
+#endif
+#if WASM_ENABLE_AOT != 0
+    if (module_inst->module_type == Wasm_Module_AoT) {
+        return aot_dump_call_stack(exec_env, false, buf, len);
+    }
+#endif
+
+    return 0;
+}
 #endif /* end of WASM_ENABLE_DUMP_CALL_STACK */
 
 bool

core/iwasm/common/wasm_runtime_common.h

@@ -404,6 +404,7 @@ typedef struct wasm_frame_t {
     uint32 module_offset;
     uint32 func_index;
     uint32 func_offset;
+    const char *func_name_wp;
 } WASMCApiFrame;
 
 /* See wasm_export.h for description */
@@ -803,6 +804,28 @@ void
 wasm_externref_cleanup(WASMModuleInstanceCommon *module_inst);
 #endif /* end of WASM_ENABLE_REF_TYPES */
 
+#if WASM_ENABLE_DUMP_CALL_STACK != 0
+/**
+ * @brief Internal implementation for dumping or printing callstack line
+ *
+ * @note if dump_or_print is true, then print to stdout directly;
+ * if dump_or_print is false, but *buf is NULL, then return the length of the
+ * line;
+ * if dump_or_print is false, and *buf is not NULL, then dump content to
+ * the memory pointed by *buf, and adjust *buf and *len according to actual
+ * bytes dumped, and return the actual dumped length
+ *
+ * @param line_buf current line to dump or print
+ * @param dump_or_print whether to print to stdout or dump to buf
+ * @param buf [INOUT] pointer to the buffer
+ * @param len [INOUT] pointer to remaining length
+ * @return bytes printed to stdout or dumped to buf
+ */
+uint32
+wasm_runtime_dump_line_buf_impl(const char *line_buf, bool dump_or_print,
+                                char **buf, uint32 *len);
+#endif /* end of WASM_ENABLE_DUMP_CALL_STACK != 0 */
+
 /* Get module of the current exec_env */
 WASMModuleCommon *
 wasm_exec_env_get_module(WASMExecEnv *exec_env);

core/iwasm/include/wasm_export.h

@@ -919,6 +919,7 @@ wasm_runtime_get_function_attachment(wasm_exec_env_t exec_env);
  */
 WASM_RUNTIME_API_EXTERN void
 wasm_runtime_set_user_data(wasm_exec_env_t exec_env, void *user_data);
+
 /**
  * Get the user data within execution environment.
  *
@@ -963,7 +964,7 @@ WASM_RUNTIME_API_EXTERN void
 wasm_runtime_set_max_thread_num(uint32_t num);
 
 /**
- * spawn a new exec_env, the spawned exec_env
+ * Spawn a new exec_env, the spawned exec_env
  *   can be used in other threads
  *
  * @param num the original exec_env
@@ -982,7 +983,7 @@ WASM_RUNTIME_API_EXTERN void
 wasm_runtime_destroy_spawned_exec_env(wasm_exec_env_t exec_env);
 
 /**
- * spawn a thread from the given exec_env
+ * Spawn a thread from the given exec_env
  *
  * @param exec_env the original exec_env
  * @param tid thread id to be returned to the caller
@@ -996,7 +997,7 @@ wasm_runtime_spawn_thread(wasm_exec_env_t exec_env, wasm_thread_t *tid,
                           wasm_thread_callback_t callback, void *arg);
 
 /**
- * waits a spawned thread to terminate
+ * Waits a spawned thread to terminate
  *
  * @param tid thread id
  * @param retval if not NULL, output the return value of the thread
@@ -1046,13 +1047,41 @@ WASM_RUNTIME_API_EXTERN bool
 wasm_externref_retain(uint32_t externref_idx);
 
 /**
- * dump the call stack
+ * Dump the call stack to stdout
  *
  * @param exec_env the execution environment
  */
 WASM_RUNTIME_API_EXTERN void
 wasm_runtime_dump_call_stack(wasm_exec_env_t exec_env);
 
+/**
+ * Get the size required to store the call stack contents, including
+ * the space for terminating null byte ('\0')
+ *
+ * @param exec_env the execution environment
+ *
+ * @return size required to store the contents, 0 means error
+ */
+WASM_RUNTIME_API_EXTERN uint32_t
+wasm_runtime_get_call_stack_buf_size(wasm_exec_env_t exec_env);
+
+/**
+ * Dump the call stack to buffer.
+ *
+ * @note this function is not thread-safe, please only use this API
+ *       when the exec_env is not executing
+ *
+ * @param exec_env the execution environment
+ * @param buf buffer to store the dumped content
+ * @param len length of the buffer
+ *
+ * @return bytes dumped to the buffer, including the terminating null
+ *         byte ('\0'), 0 means error and data in buf may be invalid
+ */
+WASM_RUNTIME_API_EXTERN uint32_t
+wasm_runtime_dump_call_stack_to_buf(wasm_exec_env_t exec_env, char *buf,
+                                    uint32_t len);
+
 /**
  * Get a custom section by name
  *

core/iwasm/interpreter/wasm_interp_classic.c

@@ -3834,7 +3834,9 @@ wasm_interp_call_wasm(WASMModuleInstance *module_inst, WASMExecEnv *exec_env,
     }
     else {
 #if WASM_ENABLE_DUMP_CALL_STACK != 0
-        wasm_interp_dump_call_stack(exec_env);
+        if (wasm_interp_create_call_stack(exec_env)) {
+            wasm_interp_dump_call_stack(exec_env, true, NULL, 0);
+        }
 #endif
         LOG_DEBUG("meet an exception %s", wasm_get_exception(module_inst));
     }

core/iwasm/interpreter/wasm_interp_fast.c

@@ -3847,7 +3847,9 @@ wasm_interp_call_wasm(WASMModuleInstance *module_inst, WASMExecEnv *exec_env,
     }
     else {
 #if WASM_ENABLE_DUMP_CALL_STACK != 0
-        wasm_interp_dump_call_stack(exec_env);
+        if (wasm_interp_create_call_stack(exec_env)) {
+            wasm_interp_dump_call_stack(exec_env, true, NULL, 0);
+        }
 #endif
     }
 

core/iwasm/interpreter/wasm_runtime.c

@@ -2485,8 +2485,8 @@ wasm_get_module_inst_mem_consumption(const WASMModuleInstance *module_inst,
                  || (WASM_ENABLE_MEMORY_TRACING != 0) */
 
 #if WASM_ENABLE_DUMP_CALL_STACK != 0
-void
+bool
-wasm_interp_dump_call_stack(struct WASMExecEnv *exec_env)
+wasm_interp_create_call_stack(struct WASMExecEnv *exec_env)
 {
     WASMModuleInstance *module_inst =
         (WASMModuleInstance *)wasm_exec_env_get_module_inst(exec_env);
@@ -2507,12 +2507,12 @@ wasm_interp_dump_call_stack(struct WASMExecEnv *exec_env)
     if (!bh_vector_destroy(module_inst->frames)
         || !bh_vector_init(module_inst->frames, n, sizeof(WASMCApiFrame),
                            false)) {
-        return;
+        return false;
     }
 
     cur_frame = first_frame;
     n = 0;
-    os_printf("\n");
+
     while (cur_frame) {
         WASMCApiFrame frame = { 0 };
         WASMFunctionInstance *func_inst = cur_frame->function;
@@ -2560,20 +2560,86 @@ wasm_interp_dump_call_stack(struct WASMExecEnv *exec_env)
             }
         }
 
-        /* function name not exported, print number instead */
+        frame.func_name_wp = func_name;
-        if (func_name == NULL) {
-            os_printf("#%02d $f%d \n", n, func_inst - module_inst->functions);
-        }
-        else {
-            os_printf("#%02d %s \n", n, func_name);
-        }
 
-        /* keep print */
+        if (!bh_vector_append(module_inst->frames, &frame)) {
-        bh_vector_append(module_inst->frames, &frame);
+            bh_vector_destroy(module_inst->frames);
+            return false;
+        }
 
         cur_frame = cur_frame->prev_frame;
         n++;
     }
-    os_printf("\n");
+
+    return true;
+}
+
+#define PRINT_OR_DUMP()                                                   \
+    do {                                                                  \
+        total_len +=                                                      \
+            wasm_runtime_dump_line_buf_impl(line_buf, print, &buf, &len); \
+        if ((!print) && buf && (len == 0)) {                              \
+            return total_len;                                             \
+        }                                                                 \
+    } while (0)
+
+uint32
+wasm_interp_dump_call_stack(struct WASMExecEnv *exec_env, bool print, char *buf,
+                            uint32 len)
+{
+    WASMModuleInstance *module_inst =
+        (WASMModuleInstance *)wasm_exec_env_get_module_inst(exec_env);
+    uint32 n = 0, total_len = 0, total_frames;
+    /* reserve 256 bytes for line buffer, any line longer than 256 bytes
+     * will be truncated */
+    char line_buf[256];
+
+    if (!module_inst->frames) {
+        return 0;
+    }
+
+    total_frames = bh_vector_size(module_inst->frames);
+    if (total_frames == 0) {
+        return 0;
+    }
+
+    snprintf(line_buf, sizeof(line_buf), "\n");
+    PRINT_OR_DUMP();
+
+    while (n < total_frames) {
+        WASMCApiFrame frame = { 0 };
+        uint32 line_length, i;
+
+        if (!bh_vector_get(module_inst->frames, n, &frame)) {
+            return 0;
+        }
+
+        /* function name not exported, print number instead */
+        if (frame.func_name_wp == NULL) {
+            line_length = snprintf(line_buf, sizeof(line_buf), "#%02d $f%d\n",
+                                   n, frame.func_index);
+        }
+        else {
+            line_length = snprintf(line_buf, sizeof(line_buf), "#%02d %s\n", n,
+                                   frame.func_name_wp);
+        }
+
+        if (line_length >= sizeof(line_buf)) {
+            uint32 line_buffer_len = sizeof(line_buf);
+            /* If line too long, ensure the last character is '\n' */
+            for (i = line_buffer_len - 5; i < line_buffer_len - 2; i++) {
+                line_buf[i] = '.';
+            }
+            line_buf[line_buffer_len - 2] = '\n';
+        }
+
+        PRINT_OR_DUMP();
+
+        n++;
+    }
+    snprintf(line_buf, sizeof(line_buf), "\n");
+    PRINT_OR_DUMP();
+
+    return total_len + 1;
 }
 #endif /* end of WASM_ENABLE_DUMP_CALL_STACK */

core/iwasm/interpreter/wasm_runtime.h

@@ -432,8 +432,25 @@ wasm_get_table_inst(const WASMModuleInstance *module_inst, const uint32 tbl_idx)
 }
 
 #if WASM_ENABLE_DUMP_CALL_STACK != 0
-void
+bool
-wasm_interp_dump_call_stack(struct WASMExecEnv *exec_env);
+wasm_interp_create_call_stack(struct WASMExecEnv *exec_env);
+
+/**
+ * @brief Dump wasm call stack or get the size
+ *
+ * @param exec_env the execution environment
+ * @param print whether to print to stdout or not
+ * @param buf buffer to store the dumped content
+ * @param len length of the buffer
+ *
+ * @return when print is true, return the bytes printed out to stdout; when
+ * print is false and buf is NULL, return the size required to store the
+ * callstack content; when print is false and buf is not NULL, return the size
+ * dumped to the buffer, 0 means error and data in buf may be invalid
+ */
+uint32
+wasm_interp_dump_call_stack(struct WASMExecEnv *exec_env, bool print, char *buf,
+                            uint32 len);
 #endif
 
 const uint8 *