Track the 'awaiter return' call stack use it to detect uncaught exceptions in async functions

runtime/vm/intermediate_language_x64.cc

 // Copyright (c) 2013, 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/compiler.h"
@@ skipping 2528 matching lines @@
                                                            bool opt) const {
   UNREACHABLE();
   return NULL;
 }
 
 
 void CatchBlockEntryInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   __ Bind(compiler->GetJumpLabel(this));
   compiler->AddExceptionHandler(catch_try_index(), try_index(),
                                 compiler->assembler()->CodeSize(),
+                                handler_token_pos(), is_generated(),
                                 catch_handler_types_, needs_stacktrace());
   // On lazy deoptimization we patch the optimized code here to enter the
   // deoptimization stub.
   const intptr_t deopt_id = Thread::ToDeoptAfter(GetDeoptId());
   if (compiler->is_optimizing()) {
     compiler->AddDeoptIndexAtCall(deopt_id);
   } else {
     compiler->AddCurrentDescriptor(RawPcDescriptors::kDeopt, deopt_id,
                                    TokenPosition::kNoSource);
   }
@@ skipping 4189 matching lines @@
   __ Drop(1);
   __ popq(result);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64