Async-step, first cut.

runtime/vm/scopes.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/scopes.h"
 
 #include "vm/object.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 
@@ skipping 231 matching lines @@
                                                      found_captured_variables);
     if (child_frame_index < min_frame_index) {
       min_frame_index = child_frame_index;
     }
     child = child->sibling();
   }
   return min_frame_index;
 }
 
 
+// The parser creates internal variables that start with ":"
+static bool IsInternalIdentifier(const String& str) {
+  ASSERT(str.Length() > 0);
+  return str.CharAt(0) == ':';
+}
+
+
 RawLocalVarDescriptors* LocalScope::GetVarDescriptors(const Function& func) {
   GrowableArray<VarDesc> vars(8);
   // First enter all variables from scopes of outer functions.
   const ContextScope& context_scope =
       ContextScope::Handle(func.context_scope());
   if (!context_scope.IsNull()) {
     ASSERT(func.IsLocalFunction());
     for (int i = 0; i < context_scope.num_variables(); i++) {
+      String& name = String::Handle(context_scope.NameAt(i));
+      RawLocalVarDescriptors::VarInfoKind kind;
+      if (!IsInternalIdentifier(name)) {
+        kind = RawLocalVarDescriptors::kContextVar;
+      } else if (name.raw() == Symbols::AsyncOperation().raw()) {
+        kind = RawLocalVarDescriptors::kAsyncOperation;
+      } else {
+        continue;
+      }
+
       VarDesc desc;
-      desc.name = &String::Handle(context_scope.NameAt(i));
-      desc.info.set_kind(RawLocalVarDescriptors::kContextVar);
+      desc.name = &name;
+      desc.info.set_kind(kind);
       desc.info.scope_id = context_scope.ContextLevelAt(i);
       desc.info.begin_pos = begin_token_pos();
       desc.info.end_pos = end_token_pos();
       ASSERT(desc.info.begin_pos <= desc.info.end_pos);
       desc.info.set_index(context_scope.ContextIndexAt(i));
       vars.Add(desc);
     }
   }
   // Now collect all variables from local scopes.
   int16_t scope_id = 0;
   CollectLocalVariables(&vars, &scope_id);
 
   if (vars.length() == 0) {
     return Object::empty_var_descriptors().raw();
   }
   const LocalVarDescriptors& var_desc =
       LocalVarDescriptors::Handle(LocalVarDescriptors::New(vars.length()));
   for (int i = 0; i < vars.length(); i++) {
     var_desc.SetVar(i, *(vars[i].name), &vars[i].info);
   }
   return var_desc.raw();
 }
 
 
-// The parser creates internal variables that start with ":"
-static bool IsInternalIdentifier(const String& str) {
-  ASSERT(str.Length() > 0);
-  return str.CharAt(0) == ':';
-}
-
-
 // Add visible variables that are declared in this scope to vars, then
 // collect visible variables of children, followed by siblings.
 void LocalScope::CollectLocalVariables(GrowableArray<VarDesc>* vars,
                                        int16_t* scope_id) {
   (*scope_id)++;
   if (num_context_variables() > 0) {
     VarDesc desc;
     desc.name = &Symbols::Empty();  // No name.
     desc.info.set_kind(RawLocalVarDescriptors::kContextLevel);
     desc.info.scope_id = *scope_id;
@@ skipping 26 matching lines @@
         // This is the local variable in which the function saves its
         // own context before calling a closure function.
         VarDesc desc;
         desc.name = &var->name();
         desc.info.set_kind(RawLocalVarDescriptors::kSavedCurrentContext);
         desc.info.scope_id = 0;
         desc.info.begin_pos = 0;
         desc.info.end_pos = 0;
         desc.info.set_index(var->index());
         vars->Add(desc);
+      } else if (var->name().raw() == Symbols::AsyncOperation().raw()) {
+        // The async continuation.
+        ASSERT(var->is_captured());
+        VarDesc desc;
+        desc.name = &var->name();
+        desc.info.set_kind(RawLocalVarDescriptors::kAsyncOperation);
+        if (var->is_captured()) {
+          ASSERT(var->owner() != NULL);
+          ASSERT(var->owner()->context_level() >= 0);
+          desc.info.scope_id = var->owner()->context_level();
+        } else {
+          desc.info.scope_id = *scope_id;
+        }
+        desc.info.begin_pos = 0;
+        desc.info.end_pos = 0;
+        desc.info.set_index(var->index());
+        vars->Add(desc);
       }
     }
   }
   LocalScope* child = this->child();
   while (child != NULL) {
     child->CollectLocalVariables(vars, scope_id);
     child = child->sibling();
   }
 }
 
@@ skipping 312 matching lines @@
     return fixed_parameter_count - (index() - kParamEndSlotFromFp);
   } else {
     // Shift negative indexes so that the lowest one is 0 (they are still
     // non-positive).
     return fixed_parameter_count - (index() - kFirstLocalSlotFromFp);
   }
 }
 
 
 }  // namespace dart