Generate code for store buffer updates in open-coded object field stores.

runtime/vm/code_generator_ia32.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/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/code_generator.h"
 
 #include "lib/error.h"
@@ skipping 843 matching lines @@
     GenerateCall(node_sequence->token_index(), &label, PcDescriptors::kOther);
 
     // If this node_sequence is the body of the function being compiled, and if
     // this function is not a closure, do not link the current context as the
     // parent of the newly allocated context, as it is not accessible. Instead,
     // save it in a pre-allocated variable and restore it on exit.
     if ((node_sequence == parsed_function_.node_sequence()) &&
         (parsed_function_.saved_context_var() != NULL)) {
       GenerateStoreVariable(
           *parsed_function_.saved_context_var(), CTX, kNoRegister);
-      const Immediate raw_null =
-          Immediate(reinterpret_cast<intptr_t>(Object::null()));
-      __ movl(CTX, raw_null);
+      const Object& raw_null = Object::ZoneHandle(Object::null());

[srdjan, 2012/06/15 21:10:34]

Object::ZoneHandle() is enough to get null handle. Rename raw_null ->
null_object, actually better:
     __ StoreIntoObjectNoBarrier(EAX, FieldAddress(..), Object::ZoneHandle())

+      __ StoreIntoObjectNoBarrier(EAX,
+                                  FieldAddress(EAX, Context::parent_offset()),
+                                  raw_null);
+    } else {
+      // Chain the new context in EAX to its parent in CTX.
+      __ StoreIntoObject(EAX, FieldAddress(EAX, Context::parent_offset()), CTX);
     }
 
-    // Chain the new context in EAX to its parent in CTX.
-    __ StoreIntoObject(EAX, FieldAddress(EAX, Context::parent_offset()), CTX);
     // Set new context as current context.
     __ movl(CTX, EAX);
     set_context_level(scope->context_level());
 
     // If this node_sequence is the body of the function being compiled, copy
     // the captured parameters from the frame into the context.
     if (node_sequence == parsed_function_.node_sequence()) {
       ASSERT(scope->context_level() == 1);
       const Immediate raw_null =
           Immediate(reinterpret_cast<intptr_t>(Object::null()));
@@ skipping 2062 matching lines @@
   const Error& error = Error::Handle(
       Parser::FormatError(script, token_index, "Error", format, args));
   va_end(args);
   Isolate::Current()->long_jump_base()->Jump(1, error);
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32