Add start to backtrace for debugger (#2407)

JerryScript-DCO-1.0-Signed-off-by: Daniella Barsony bella@inf.u-szeged.hu

jerry-core/debugger/debugger.c

@@ -78,6 +78,8 @@ jerry_debugger_send_backtrace (uint8_t *recv_buffer_p) /**< pointer to the recei
 {
   JERRY_DEBUGGER_RECEIVE_BUFFER_AS (jerry_debugger_receive_get_backtrace_t, get_backtrace_p);
 
+  uint32_t min_depth;
+  memcpy (&min_depth, get_backtrace_p->min_depth, sizeof (uint32_t));
   uint32_t max_depth;
   memcpy (&max_depth, get_backtrace_p->max_depth, sizeof (uint32_t));
 
@@ -96,35 +98,45 @@ jerry_debugger_send_backtrace (uint8_t *recv_buffer_p) /**< pointer to the recei
   const size_t max_frame_count = JERRY_DEBUGGER_SEND_MAX (jerry_debugger_frame_t);
   const size_t max_message_size = JERRY_DEBUGGER_SEND_SIZE (max_frame_count, jerry_debugger_frame_t);
 
-  while (frame_ctx_p != NULL && max_depth > 0)
+  if (min_depth <= max_depth)
   {
-    if (frame_ctx_p->bytecode_header_p->status_flags & CBC_CODE_FLAGS_DEBUGGER_IGNORE)
+    uint32_t min_depth_offset = 0;
+
+    while (frame_ctx_p != NULL && min_depth_offset < min_depth)
     {
       frame_ctx_p = frame_ctx_p->prev_context_p;
-      continue;
+      min_depth_offset++;
     }
 
-    if (current_frame >= max_frame_count)
+    while (frame_ctx_p != NULL && min_depth_offset++ < max_depth)
     {
-      if (!jerry_debugger_send (max_message_size))
+      if (frame_ctx_p->bytecode_header_p->status_flags & CBC_CODE_FLAGS_DEBUGGER_IGNORE)
       {
-        return;
+        frame_ctx_p = frame_ctx_p->prev_context_p;
+        continue;
       }
-      current_frame = 0;
+
+      if (current_frame >= max_frame_count)
+      {
+        if (!jerry_debugger_send (max_message_size))
+        {
+          return;
+        }
+        current_frame = 0;
+      }
+
+      jerry_debugger_frame_t *frame_p = backtrace_p->frames + current_frame;
+
+      jmem_cpointer_t byte_code_cp;
+      JMEM_CP_SET_NON_NULL_POINTER (byte_code_cp, frame_ctx_p->bytecode_header_p);
+      memcpy (frame_p->byte_code_cp, &byte_code_cp, sizeof (jmem_cpointer_t));
+
+      uint32_t offset = (uint32_t) (frame_ctx_p->byte_code_p - (uint8_t *) frame_ctx_p->bytecode_header_p);
+      memcpy (frame_p->offset, &offset, sizeof (uint32_t));
+
+      frame_ctx_p = frame_ctx_p->prev_context_p;
+      current_frame++;
     }
-
-    jerry_debugger_frame_t *frame_p = backtrace_p->frames + current_frame;
-
-    jmem_cpointer_t byte_code_cp;
-    JMEM_CP_SET_NON_NULL_POINTER (byte_code_cp, frame_ctx_p->bytecode_header_p);
-    memcpy (frame_p->byte_code_cp, &byte_code_cp, sizeof (jmem_cpointer_t));
-
-    uint32_t offset = (uint32_t) (frame_ctx_p->byte_code_p - (uint8_t *) frame_ctx_p->bytecode_header_p);
-    memcpy (frame_p->offset, &offset, sizeof (uint32_t));
-
-    frame_ctx_p = frame_ctx_p->prev_context_p;
-    current_frame++;
-    max_depth--;
   }
 
   size_t message_size = current_frame * sizeof (jerry_debugger_frame_t);

jerry-core/debugger/debugger.h

@@ -376,6 +376,7 @@ typedef struct
 typedef struct
 {
   uint8_t type; /**< type of the message */
+  uint8_t min_depth[sizeof (uint32_t)]; /**< minimum depth*/
   uint8_t max_depth[sizeof (uint32_t)]; /**< maximum depth (0 - unlimited) */
 } jerry_debugger_receive_get_backtrace_t;
 

jerry-debugger/jerry-client-ws.py

@@ -200,13 +200,14 @@ class JerryFunction(object):
 
 
 class DebuggerPrompt(Cmd):
-
+    # pylint: disable=too-many-instance-attributes,too-many-arguments
     def __init__(self, debugger):
         Cmd.__init__(self)
         self.debugger = debugger
         self.stop = False
         self.quit = False
         self.cont = True
+        self.min_depth = 0
         self.non_interactive = False
         self.client_sources = []
 
@@ -348,22 +349,36 @@ class DebuggerPrompt(Cmd):
     def do_backtrace(self, args):
         """ Get backtrace data from debugger """
         max_depth = 0
+        self.min_depth = 0
 
         if args:
+            args = args.split(" ")
             try:
-                max_depth = int(args)
+                if len(args) == 2:
-                if max_depth <= 0:
+                    self.min_depth = int(args[0])
-                    print("Error: Positive integer number expected")
+                    max_depth = int(args[1])
-                    return
+                    if max_depth <= 0 or self.min_depth < 0:
+                        print("Error: Positive integer number expected")
+                        return
+                    if self.min_depth > max_depth:
+                        print("Error: Start depth needs to be lower than or equal to max depth")
+                        return
+                else:
+                    max_depth = int(args[0])
+                    if max_depth <= 0:
+                        print("Error: Positive integer number expected")
+                        return
+
             except ValueError as val_errno:
                 print("Error: Positive integer number expected, %s" % (val_errno))
                 return
 
-        message = struct.pack(self.debugger.byte_order + "BBIB" + self.debugger.idx_format,
+        message = struct.pack(self.debugger.byte_order + "BBIB" + self.debugger.idx_format + self.debugger.idx_format,
                               WEBSOCKET_BINARY_FRAME | WEBSOCKET_FIN_BIT,
-                              WEBSOCKET_FIN_BIT + 1 + 4,
+                              WEBSOCKET_FIN_BIT + 1 + 4 + 4,
                               0,
                               JERRY_DEBUGGER_GET_BACKTRACE,
+                              self.min_depth,
                               max_depth)
         self.debugger.send_message(message)
         self.stop = True
@@ -1199,7 +1214,10 @@ def main():
             exception_string += data[3:]
 
         elif buffer_type in [JERRY_DEBUGGER_BACKTRACE, JERRY_DEBUGGER_BACKTRACE_END]:
-            frame_index = 0
+            if prompt.min_depth != 0:
+                frame_index = prompt.min_depth
+            else:
+                frame_index = 0
 
             while True:
 

tests/debugger/do_backtrace.cmd

@@ -4,9 +4,15 @@ next
 step
 next
 s
+bt 1 2
 bt
+bt 2
 n
 n
 s
 backtrace
+bt 4 4
+bt 600 919
+bt 3 500
+bt 4 3
 c

tests/debugger/do_backtrace.expected

@@ -14,10 +14,15 @@ out: function test
 Stopped at tests/debugger/do_backtrace.js:33 (in test() at line:30, col:1)
 (jerry-debugger) s
 Stopped at tests/debugger/do_backtrace.js:23 (in foo() at line:21, col:1)
+(jerry-debugger) bt 1 2
+Frame 1: tests/debugger/do_backtrace.js:33 (in test() at line:30, col:1)
 (jerry-debugger) bt
 Frame 0: tests/debugger/do_backtrace.js:23 (in foo() at line:21, col:1)
 Frame 1: tests/debugger/do_backtrace.js:33 (in test() at line:30, col:1)
 Frame 2: tests/debugger/do_backtrace.js:40
+(jerry-debugger) bt 2
+Frame 0: tests/debugger/do_backtrace.js:23 (in foo() at line:21, col:1)
+Frame 1: tests/debugger/do_backtrace.js:33 (in test() at line:30, col:1)
 (jerry-debugger) n
 out: function foo
 Stopped at tests/debugger/do_backtrace.js:24 (in foo() at line:21, col:1)
@@ -30,5 +35,11 @@ Frame 0: tests/debugger/do_backtrace.js:18 (in f4() at line:17, col:1)
 Frame 1: tests/debugger/do_backtrace.js:25 (in foo() at line:21, col:1)
 Frame 2: tests/debugger/do_backtrace.js:33 (in test() at line:30, col:1)
 Frame 3: tests/debugger/do_backtrace.js:40
+(jerry-debugger) bt 4 4
+(jerry-debugger) bt 600 919
+(jerry-debugger) bt 3 500
+Frame 3: tests/debugger/do_backtrace.js:40
+(jerry-debugger) bt 4 3
+Error: Start depth needs to be lower than or equal to max depth
 (jerry-debugger) c
 out: function f4