Deal with spurious breakpoints due to recursion.

random-ua · Aug 6, 2014 · 2604471 · 2604471
1 parent 69e3ef8
commit 2604471
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Showing 2 changed files with 28 additions and 6 deletions.
diff --git a/SimpleTraceTarget/SimpleTraceTarget/main.m b/SimpleTraceTarget/SimpleTraceTarget/main.m
@@ -19,9 +19,23 @@ void a(void)
  printf("Cycle\n");
 }
 
+void c(int i);
+void d(int i)
+{
+ c(i-1);
+}
+
+void c(int i)
+{
+ if (i > 0) {
+ d(i);
+ }
+}
+
 void breakpoint(void)
 {
  a();
+ c(1);
 }
 
 int main(int argc, const char * argv[])

diff --git a/trace.py b/trace.py
@@ -66,6 +66,9 @@ def __init__(self, target, thread, frame, result):
  def update_frame(self, frame):
  self.frame = frame
 
+ def is_frame_valid(self):
+ return self.frame.IsValid()
+
  def instrument_calls_syscalls_and_jmps(self):
  # TODO: symbols vs functions
  print >>self.result, self.frame.GetFunction()
@@ -136,31 +139,31 @@ def clear_return_breakpoint(self):
  self.return_breakpoint == None
 
  def is_stopped_on_call(self, frame):
- if frame.GetFrameID() != self.frame.GetFrameID():
+ if not self.frame.IsValid() or frame.GetFrameID() != self.frame.GetFrameID():
  print >>self.result, "A Frames don't match, ours: {}, valid: {}, submitted: {}".format(self.frame.GetFrameID(), self.frame.IsValid(), frame.GetFrameID())
  return False
 
  stop_address = frame.GetPC()
  return stop_address in self.call_breakpoints
 
  def is_stopped_on_syscall(self, frame):
- if frame.GetFrameID() != self.frame.GetFrameID():
+ if not self.frame.IsValid() or frame.GetFrameID() != self.frame.GetFrameID():
  print >>self.result, "D Frames don't match, ours: {}, valid: {}, submitted: {}".format(self.frame.GetFrameID(), self.frame.IsValid(), frame.GetFrameID())
  return False
 
  stop_address = frame.GetPC()
  return stop_address in self.syscall_breakpoints
 
  def is_stopped_on_jmp(self, frame, validate_saved_frame):
- if validate_saved_frame and frame.GetFrameID() != self.frame.GetFrameID():
+ if validate_saved_frame and (not self.frame.IsValid() or frame.GetFrameID() != self.frame.GetFrameID()):
  print >>self.result, "B Frames don't match, ours: {}, valid: {}, submitted: {}".format(self.frame.GetFrameID(), self.frame.IsValid(), frame.GetFrameID())
  return False
 
  stop_address = frame.GetPC()
  return stop_address in self.jmp_breakpoints
 
  def is_stopped_on_return(self, frame):
- if frame.GetFrameID() != self.frame.GetFrameID():
+ if not self.frame.IsValid() or frame.GetFrameID() != self.frame.GetFrameID():
  print >>self.result, "C Frames don't match, ours: {}, valid: {}, submitted: {}".format(self.frame.GetFrameID(), self.frame.IsValid(), frame.GetFrameID())
  return False
 
@@ -362,8 +365,13 @@ def trace(debugger, command, result, internal_dict):
  instrumented_frame.update_frame(frame)
  instrumented_frame.instrument_calls_syscalls_and_jmps()
  else:
- print >>result, "Failed to detect return, call or jmp. Error exit"
- break
+ top_instrumented_frame = instrumented_frame
+ if top_instrumented_frame == None:
+ top_instrumented_frame = parent_instrumented_frame
+ if top_instrumented_frame == None or not top_instrumented_frame.is_frame_valid():
+ print >>result, "Failed to detect return, call or jmp. Error exit"
+ break
+ print >>result, "Unexpected breakpoint but top frame still valid, continuing"
 
  # TODO: clear instrumented frames, on errors there
  # may be breakpoints left, what needs to be worked out