Bubble up exceptions throw async/await.

runtime/vm/flow_graph_builder.cc

 // 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.
 
 #include "vm/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/class_finalizer.h"
@@ skipping 1451 matching lines @@
                                         JoinEntryInstr* target) {
   // Building a jump consists of the following actions:
   // * Record the current continuation result in a temporary.
   // * Restore the old context.
   // * Overwrite the old context's continuation result with the temporary.
   // * Append a Goto to the target's join.
   LocalVariable* old_ctx = lookup_scope->LookupVariable(
       Symbols::AwaitContextVar(), false);
   LocalVariable* continuation_result = lookup_scope->LookupVariable(
       Symbols::AsyncOperationParam(), false);
+  LocalVariable* continuation_error = lookup_scope->LookupVariable(
+      Symbols::AsyncOperationErrorParam(), false);
   ASSERT((continuation_result != NULL) && continuation_result->is_captured());
+  ASSERT((continuation_error != NULL) && continuation_error->is_captured());
   ASSERT((old_ctx != NULL) && old_ctx->is_captured());
   // Before restoring the continuation context we need to temporary save the
-  // current continuation result.
-  Value* continuation_result_value = Bind(BuildLoadLocal(*continuation_result));
-  Do(BuildStoreExprTemp(continuation_result_value));
-
+  // result and error parameter.
+  LocalVariable* temp_result_var = EnterTempLocalScope(
+      Bind(BuildLoadLocal(*continuation_result)));
+  LocalVariable* temp_error_var = EnterTempLocalScope(
+      Bind(BuildLoadLocal(*continuation_error)));
   // Restore the saved continuation context.
   BuildRestoreContext(*old_ctx);
 
   // Pass over the continuation result.
-  Value* saved_continuation_result = Bind(BuildLoadExprTemp());
+
   // FlowGraphBuilder is at top context level, but the await target has possibly
   // been recorded in a nested context (old_ctx_level). We need to unroll
   // manually here.
-  LocalVariable* tmp_var = EnterTempLocalScope(saved_continuation_result);
   intptr_t delta = old_ctx_level -
                    continuation_result->owner()->context_level();
   ASSERT(delta >= 0);
   Value* context = Bind(new(I) CurrentContextInstr());
   while (delta-- > 0) {
     context = Bind(new(I) LoadFieldInstr(
         context, Context::parent_offset(), Type::ZoneHandle(I, Type::null()),
         Scanner::kNoSourcePos));
   }
-  Value* tmp_val = Bind(new(I) LoadLocalInstr(*tmp_var));
+  LocalVariable* temp_context_var = EnterTempLocalScope(context);
+
+  Value* context_val = Bind(new(I) LoadLocalInstr(*temp_context_var));
+  Value* store_val = Bind(new(I) LoadLocalInstr(*temp_result_var));
   StoreInstanceFieldInstr* store = new(I) StoreInstanceFieldInstr(
       Context::variable_offset(continuation_result->index()),
-      context,
-      tmp_val,
+      context_val,
+      store_val,
       kEmitStoreBarrier,
       Scanner::kNoSourcePos);
   Do(store);
-  Do(ExitTempLocalScope(tmp_var));
+  context_val = Bind(new(I) LoadLocalInstr(*temp_context_var));
+  store_val = Bind(new(I) LoadLocalInstr(*temp_error_var));
+  StoreInstanceFieldInstr* store2 = new(I) StoreInstanceFieldInstr(
+      Context::variable_offset(continuation_error->index()),
+      context_val,
+      store_val,
+      kEmitStoreBarrier,
+      Scanner::kNoSourcePos);
+  Do(store2);
+
+  Do(ExitTempLocalScope(temp_context_var));
+  Do(ExitTempLocalScope(temp_error_var));
+  Do(ExitTempLocalScope(temp_result_var));
 
   // Goto saved join.
   Goto(target);
 }
 
 
 // Used for type casts and to test assignments.
 Value* EffectGraphVisitor::BuildAssignableValue(intptr_t token_pos,
                                                 Value* value,
                                                 const AbstractType& dst_type,
@@ skipping 2691 matching lines @@
   Report::MessageF(Report::kBailout,
                    Script::Handle(function.script()),
                    function.token_pos(),
                    "FlowGraphBuilder Bailout: %s %s",
                    String::Handle(function.name()).ToCString(),
                    reason);
   UNREACHABLE();
 }
 
 }  // namespace dart