Track async causal stack traces

runtime/vm/raw_object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_RAW_OBJECT_H_
 #define RUNTIME_VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/atomic.h"
 #include "vm/globals.h"
@@ skipping 2123 matching lines @@
 
 
 // VM type for capturing stacktraces when exceptions are thrown,
 // Currently we don't have any interface that this object is supposed
 // to implement so we just support the 'toString' method which
 // converts the stack trace into a string.
 class RawStackTrace : public RawInstance {
   RAW_HEAP_OBJECT_IMPLEMENTATION(StackTrace);
 
   RawObject** from() {
-    return reinterpret_cast<RawObject**>(&ptr()->code_array_);
+    return reinterpret_cast<RawObject**>(&ptr()->async_link_);
   }
+  RawStackTrace* async_link_;  // Link to parent async stack trace.
   RawArray* code_array_;       // Code object for each frame in the stack trace.
   RawArray* pc_offset_array_;  // Offset of PC for each frame.
   RawObject** to() {
     return reinterpret_cast<RawObject**>(&ptr()->pc_offset_array_);
   }
   // False for pre-allocated stack trace (used in OOM and Stack overflow).
   bool expand_inlined_;
 };
 
 
@@ skipping 282 matching lines @@
   COMPILE_ASSERT(kExternalTypedDataInt8ArrayCid ==
                  kTypedDataInt8ArrayViewCid + 15);
   COMPILE_ASSERT(kByteBufferCid == kExternalTypedDataInt8ArrayCid + 14);
   COMPILE_ASSERT(kNullCid == kByteBufferCid + 1);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_RAW_OBJECT_H_