57 // of the top_frame when the parent of the top_frame is interpreted and
  58 // the grandparent is compiled. However, in this method we do not know
  59 // the relationship of the current _frame relative to the top_frame so
  60 // we implement a more broad sanity check. When the previous callee is
  61 // interpreted and the current sender is compiled, we verify that the
  62 // current sender is also walkable. If it is not walkable, then we mark
  63 // the current vframeStream as at the end.
  64 void vframeStreamSamples::samples_next() {
  65   // handle frames with inlining
  66   if (_mode == compiled_mode &&
  67       vframeStreamCommon::fill_in_compiled_inlined_sender()) {
  68     return;
  69   }
  70 
  71   // handle general case
  72   int loop_count = 0;
  73   int loop_max = MaxJavaStackTraceDepth * 2;
  74   do {
  75     loop_count++;
  76     // By the time we get here we should never see unsafe but better safe then segv'd
  77     if (loop_count > loop_max || !_frame.safe_for_sender(_thread)) {
  78       _mode = at_end_mode;
  79       return;
  80     }
  81     _frame = _frame.sender(&_reg_map);
  82   } while (!fill_from_frame());
  83 }
  84 
  85 static JfrStackTraceRepository* _instance = NULL;
  86 
  87 JfrStackTraceRepository& JfrStackTraceRepository::instance() {
  88   return *_instance;
  89 }
  90 
  91 JfrStackTraceRepository* JfrStackTraceRepository::create() {
  92   assert(_instance == NULL, "invariant");
  93   _instance = new JfrStackTraceRepository();
  94   return _instance;
  95 }
  96 
  97 void JfrStackTraceRepository::destroy() {

  57 // of the top_frame when the parent of the top_frame is interpreted and
  58 // the grandparent is compiled. However, in this method we do not know
  59 // the relationship of the current _frame relative to the top_frame so
  60 // we implement a more broad sanity check. When the previous callee is
  61 // interpreted and the current sender is compiled, we verify that the
  62 // current sender is also walkable. If it is not walkable, then we mark
  63 // the current vframeStream as at the end.
  64 void vframeStreamSamples::samples_next() {
  65   // handle frames with inlining
  66   if (_mode == compiled_mode &&
  67       vframeStreamCommon::fill_in_compiled_inlined_sender()) {
  68     return;
  69   }
  70 
  71   // handle general case
  72   int loop_count = 0;
  73   int loop_max = MaxJavaStackTraceDepth * 2;
  74   do {
  75     loop_count++;
  76     // By the time we get here we should never see unsafe but better safe then segv'd
  77     if (((loop_max != 0) && (loop_count > loop_max)) || !_frame.safe_for_sender(_thread)) {
  78       _mode = at_end_mode;
  79       return;
  80     }
  81     _frame = _frame.sender(&_reg_map);
  82   } while (!fill_from_frame());
  83 }
  84 
  85 static JfrStackTraceRepository* _instance = NULL;
  86 
  87 JfrStackTraceRepository& JfrStackTraceRepository::instance() {
  88   return *_instance;
  89 }
  90 
  91 JfrStackTraceRepository* JfrStackTraceRepository::create() {
  92   assert(_instance == NULL, "invariant");
  93   _instance = new JfrStackTraceRepository();
  94   return _instance;
  95 }
  96 
  97 void JfrStackTraceRepository::destroy() {