Sane asynchronous debugging and stack traces

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
diff --git a/runtime/vm/compiler.cc b/runtime/vm/compiler.cc
index fee4b89553a3717ade51339da924ae6c515c8232..2548c354bc785c4029a32337b05ff3ac7ea0b67c 100644
--- a/runtime/vm/compiler.cc
+++ b/runtime/vm/compiler.cc
@@ -549,6 +549,30 @@ void CompileParsedFunctionHelper::FinalizeCompilation(
     function.set_usage_counter(INT_MIN);
   }
 
+#if !defined(PRODUCT)
+  ZoneGrowableArray<TokenPosition>* await_token_positions =
+      flow_graph->await_token_positions();
+  if (await_token_positions != NULL) {
+    Smi& token_pos_value = Smi::Handle(zone);
+    if (await_token_positions->length() > 0) {
+      const Array& await_to_token_map = Array::Handle(
+          zone, Array::New(await_token_positions->length(), Heap::kOld));
+      ASSERT(!await_to_token_map.IsNull());
+      for (intptr_t i = 0; i < await_token_positions->length(); i++) {
+        TokenPosition token_pos = await_token_positions->At(i).FromSynthetic();
+        if (!token_pos.IsReal()) {
+          // Some async machinary uses kNoSourcePos. Skip these.
+          continue;
+        }
+        ASSERT(token_pos.IsReal());
+        token_pos_value = Smi::New(token_pos.value());
+        await_to_token_map.SetAt(i, token_pos_value);
+      }
+      code.SetAwaitTokenPositions(await_to_token_map);
+    }
+  }
+#endif  // !defined(PRODUCT)
+
   const Array& intervals = graph_compiler->inlined_code_intervals();
   INC_STAT(thread(), total_code_size, intervals.Length() * sizeof(uword));
   code.SetInlinedIntervals(intervals);