Debugger: fix stepping next with trycatch recursion

Added depth check to StepNextContinue. Do step out and queue actual StepNext if check failed.

R=yangguo@chromium.org,danno@chromium.org,vegorov@chromium.org
BUG=v8:1639
TEST=

Review URL: http://codereview.chromium.org/7780033
Patch from Fedor Indutny <fedor@indutny.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@9264 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Author: yangguo@chromium.org

AUTHORS

@@ -21,6 +21,7 @@ Daniel Andersson <kodandersson@gmail.com>
 Daniel James <dnljms@gmail.com>
 Dineel D Sule <dsule@codeaurora.org>
 Erich Ocean <erich.ocean@me.com>
+Fedor Indutny <fedor@indutny.com>
 Jan de Mooij <jandemooij@gmail.com>
 Jay Freeman <saurik@saurik.com>
 Joel Stanley <joel.stan@gmail.com>

src/debug.cc

@@ -543,6 +543,7 @@ void Debug::ThreadInit() {
   thread_local_.last_statement_position_ = RelocInfo::kNoPosition;
   thread_local_.step_count_ = 0;
   thread_local_.last_fp_ = 0;
+  thread_local_.queued_step_count_ = 0;
   thread_local_.step_into_fp_ = 0;
   thread_local_.step_out_fp_ = 0;
   thread_local_.after_break_target_ = 0;
@@ -958,14 +959,49 @@ Object* Debug::Break(Arguments args) {
     // Clear all current stepping setup.
     ClearStepping();
 
-    // Notify the debug event listeners.
-    isolate_->debugger()->OnDebugBreak(break_points_hit, false);
+    if (thread_local_.queued_step_count_ > 0) {
+      // Perform queued steps
+      int step_count = thread_local_.queued_step_count_;
+
+      // Clear queue
+      thread_local_.queued_step_count_ = 0;
+
+      PrepareStep(StepNext, step_count);
+    } else {
+      // Notify the debug event listeners.
+      isolate_->debugger()->OnDebugBreak(break_points_hit, false);
+    }
   } else if (thread_local_.last_step_action_ != StepNone) {
     // Hold on to last step action as it is cleared by the call to
     // ClearStepping.
     StepAction step_action = thread_local_.last_step_action_;
     int step_count = thread_local_.step_count_;
 
+    // If StepNext goes deeper in code, StepOut until original frame
+    // and keep step count queued up in the meantime.
+    if (step_action == StepNext && frame->fp() < thread_local_.last_fp_) {
+      // Count frames until target frame
+      int count = 0;
+      JavaScriptFrameIterator it(isolate_);
+      while (!it.done() && it.frame()->fp() != thread_local_.last_fp_) {
+        count++;
+        it.Advance();
+      }
+
+      // If we found original frame
+      if (it.frame()->fp() == thread_local_.last_fp_) {
+        if (step_count > 1) {
+          // Save old count and action to continue stepping after
+          // StepOut
+          thread_local_.queued_step_count_ = step_count - 1;
+        }
+
+        // Set up for StepOut to reach target frame
+        step_action = StepOut;
+        step_count = count;
+      }
+    }
+
     // Clear all current stepping setup.
     ClearStepping();
 
@@ -1455,6 +1491,13 @@ void Debug::PrepareStep(StepAction step_action, int step_count) {
 // steps before reporting break back to the debugger.
 bool Debug::StepNextContinue(BreakLocationIterator* break_location_iterator,
                              JavaScriptFrame* frame) {
+  // StepNext and StepOut shouldn't bring us deeper in code, so last frame
+  // shouldn't be a parent of current frame.
+  if (thread_local_.last_step_action_ == StepNext ||
+      thread_local_.last_step_action_ == StepOut) {
+    if (frame->fp() < thread_local_.last_fp_) return true;
+  }
+
   // If the step last action was step next or step in make sure that a new
   // statement is hit.
   if (thread_local_.last_step_action_ == StepNext ||

src/debug.h

@@ -508,6 +508,9 @@ class Debug {
     // Frame pointer from last step next action.
     Address last_fp_;
 
+    // Number of queued steps left to perform before debug event.
+    int queued_step_count_;
+
     // Frame pointer for frame from which step in was performed.
     Address step_into_fp_;