V8_Fatal now prints C++ stack trace in debug mode.

src/checks.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 28 matching lines @@
   fflush(stdout);
   fflush(stderr);
   fatal_error_handler_nesting_depth++;
   // First time we try to print an error message
   if (fatal_error_handler_nesting_depth < 2) {
     i::OS::PrintError("\n\n#\n# Fatal error in %s, line %d\n# ", file, line);
     va_list arguments;
     va_start(arguments, format);
     i::OS::VPrintError(format, arguments);
     va_end(arguments);
-    i::OS::PrintError("\n#\n\n");
+    i::OS::PrintError("\n#\n");
+    i::OS::DumpBacktrace();
   }
   // First two times we may try to print a stack dump.
   if (fatal_error_handler_nesting_depth < 3) {
     if (i::FLAG_stack_trace_on_abort) {
       // Call this one twice on double fault
       i::Isolate::Current()->PrintStack();
     }
   }
   i::OS::Abort();
 }
@@ skipping 41 matching lines @@
 
 
 namespace v8 { namespace internal {
 
   bool EnableSlowAsserts() { return FLAG_enable_slow_asserts; }
 
   intptr_t HeapObjectTagMask() { return kHeapObjectTagMask; }
 
 } }  // namespace v8::internal