Sane asynchronous debugging and stack traces

runtime/vm/thread.h

Index: runtime/vm/thread.h
diff --git a/runtime/vm/thread.h b/runtime/vm/thread.h
index 57a7c1f69405478a110f470e7af729d1d31e5dbc..88b43388155e0280a60f5fd9a48357c79eae98b0 100644
--- a/runtime/vm/thread.h
+++ b/runtime/vm/thread.h
@@ -44,10 +44,12 @@ class RawObject;
 class RawCode;
 class RawError;
 class RawGrowableObjectArray;
+class RawStackTrace;
 class RawString;
 class RuntimeEntry;
 class Smi;
 class StackResource;
+class StackTrace;
 class String;
 class TimelineStream;
 class TypeArguments;
@@ -505,6 +507,13 @@ class Thread : public BaseThread {
   void set_sticky_error(const Error& value);
   void clear_sticky_error();
 
+  RawStackTrace* async_stack_trace() const;
+  void set_async_stack_trace(const StackTrace& stack_trace);
+  void clear_async_stack_trace();
+  static intptr_t async_stack_trace_offset() {
+    return OFFSET_OF(Thread, async_stack_trace_);
+  }
+
   CompilerStats* compiler_stats() { return compiler_stats_; }
 
 #if defined(DEBUG)
@@ -727,6 +736,7 @@ class Thread : public BaseThread {
   uword resume_pc_;
 
   RawError* sticky_error_;
+  RawStackTrace* async_stack_trace_;
 
   CompilerStats* compiler_stats_;