Sane asynchronous debugging and stack traces

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 3675bfb32ff3382e8771900b79c80636bf4cdfb1..66a547261a5e898d6494427eebd6f987ac17a0a5 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -10659,7 +10659,17 @@ RawLibrary* Library::NewLibraryHelper(const String& url, bool import_core_lib) {
   result.set_native_entry_symbol_resolver(NULL);
   result.set_is_in_fullsnapshot(false);
   result.StoreNonPointer(&result.raw_ptr()->corelib_imported_, true);
-  result.set_debuggable(!dart_private_scheme);
+  if (dart_private_scheme) {
+    // Never debug dart:_ libraries.
+    result.set_debuggable(false);
+  } else if (dart_scheme) {
+    // Only debug dart: libraries if we have been requested to show invisible
+    // frames.
+    result.set_debuggable(FLAG_show_invisible_frames);
+  } else {
+    // Default to debuggable for all other libraries.
+    result.set_debuggable(true);
+  }
   result.set_is_dart_scheme(dart_scheme);
   result.StoreNonPointer(&result.raw_ptr()->load_state_,
                          RawLibrary::kAllocated);
@@ -14066,6 +14076,16 @@ RawCode* Code::GetStaticCallTargetCodeAt(uword pc) const {
 }
 
 
+void Code::SetAwaitTokenPositions(const Array& await_token_positions) const {
+#if defined(DART_PRECOMPILED_RUNTIME)
+  UNREACHABLE();
+#else
+  ASSERT(await_token_positions.IsOld());
+  StorePointer(&raw_ptr()->await_token_positions_, await_token_positions.raw());
+#endif
+}
+
+
 void Code::SetStaticCallTargetCodeAt(uword pc, const Code& code) const {
 #if defined(DART_PRECOMPILED_RUNTIME)
   UNREACHABLE();
@@ -22625,8 +22645,16 @@ const char* StackTrace::ToCStringInternal(intptr_t* frame_index,
   intptr_t total_len = 0;
   GrowableArray<char*> frame_strings;
   for (intptr_t i = 0; (i < Length()) && (*frame_index < max_frames); i++) {
+    code = CodeAtFrame(i);
     function = FunctionAtFrame(i);
-    if (function.IsNull()) {
+    if (code.raw() == StubCode::AsynchronousGapMarker_entry()->code()) {
+      const char* kAsynchronousGap = "<asynchronous suspension>\n";
+      intptr_t asynchronous_gap_len = strlen(kAsynchronousGap) + 1;
+      char* chars = zone->Alloc<char>(asynchronous_gap_len);
+      OS::SNPrint(chars, asynchronous_gap_len, "%s", kAsynchronousGap);
+      frame_strings.Add(chars);
+      total_len += asynchronous_gap_len;
+    } else if (function.IsNull()) {
       // Check for a null function, which indicates a gap in a StackOverflow or
       // OutOfMemory trace.
       if ((i < (Length() - 1)) &&
@@ -22642,7 +22670,6 @@ const char* StackTrace::ToCStringInternal(intptr_t* frame_index,
         (*frame_index) += Smi::Value(PcOffsetAtFrame(i));
       }
     } else {
-      code = CodeAtFrame(i);
       ASSERT(function.raw() == code.function());
       uword pc = code.PayloadStart() + Smi::Value(PcOffsetAtFrame(i));
       if (code.is_optimized() && expand_inlined() &&