1 files changed, 41 insertions, 8 deletions

diff --git a/deps/v8/src/debug.cc b/deps/v8/src/debug.cc
index f8a1ecf4f9..9efb5c37aa 100644
--- a/deps/v8/src/debug.cc
+++ b/deps/v8/src/debug.cc
@@ -892,6 +892,16 @@ void Debug::Iterate(ObjectVisitor* v) {
 }
 
 
+void Debug::PutValuesOnStackAndDie(int start,
+                                   Address c_entry_fp,
+                                   Address last_fp,
+                                   Address larger_fp,
+                                   int count,
+                                   int end) {
+  OS::Abort();
+}
+
+
 Object* Debug::Break(Arguments args) {
   Heap* heap = isolate_->heap();
   HandleScope scope(isolate_);
@@ -984,11 +994,34 @@ Object* Debug::Break(Arguments args) {
       // Count frames until target frame
       int count = 0;
       JavaScriptFrameIterator it(isolate_);
-      while (!it.done() && it.frame()->fp() != thread_local_.last_fp_) {
+      while (!it.done() && it.frame()->fp() < thread_local_.last_fp_) {
         count++;
         it.Advance();
       }
 
+      // Catch the cases that would lead to crashes and capture
+      // - C entry FP at which to start stack crawl.
+      // - FP of the frame at which we plan to stop stepping out (last FP).
+      // - current FP that's larger than last FP.
+      // - Counter for the number of steps to step out.
+      if (it.done()) {
+        // We crawled the entire stack, never reaching last_fp_.
+        PutValuesOnStackAndDie(0xBEEEEEEE,
+                               frame->fp(),
+                               thread_local_.last_fp_,
+                               NULL,
+                               count,
+                               0xFEEEEEEE);
+      } else if (it.frame()->fp() != thread_local_.last_fp_) {
+        // We crawled over last_fp_, without getting a match.
+        PutValuesOnStackAndDie(0xBEEEEEEE,
+                               frame->fp(),
+                               thread_local_.last_fp_,
+                               it.frame()->fp(),
+                               count,
+                               0xFEEEEEEE);
+      }
+
       // If we found original frame
       if (it.frame()->fp() == thread_local_.last_fp_) {
         if (step_count > 1) {
@@ -1857,13 +1890,6 @@ static void RedirectActivationsToRecompiledCodeOnThread(
       // break slots.
       debug_break_slot_count++;
     }
-    if (frame_code->has_self_optimization_header() &&
-        !new_code->has_self_optimization_header()) {
-      delta -= FullCodeGenerator::self_optimization_header_size();
-    } else {
-      ASSERT(frame_code->has_self_optimization_header() ==
-             new_code->has_self_optimization_header());
-    }
     int debug_break_slot_bytes =
         debug_break_slot_count * Assembler::kDebugBreakSlotLength;
     if (FLAG_trace_deopt) {
@@ -2234,6 +2260,13 @@ void Debug::FramesHaveBeenDropped(StackFrame::Id new_break_frame_id,
 }
 
 
+const int Debug::FramePaddingLayout::kInitialSize = 1;
+
+
+// Any even value bigger than kInitialSize as needed for stack scanning.
+const int Debug::FramePaddingLayout::kPaddingValue = kInitialSize + 1;
+
+
 bool Debug::IsDebugGlobal(GlobalObject* global) {
   return IsLoaded() && global == debug_context()->global();
 }