Collect type feedback for fields.

runtime/vm/raw_object.h

 // 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.
 
 #ifndef VM_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/token.h"
@@ skipping 646 matching lines @@
 
 class RawField : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Field);
 
   RawObject** from() { return reinterpret_cast<RawObject**>(&ptr()->name_); }
   RawString* name_;
   RawObject* owner_;  // Class or patch class or mixin class
                       // where this field is defined.
   RawAbstractType* type_;
   RawInstance* value_;  // Offset in words for instance and value for static.
-  RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->value_); }
+  RawArray* dependent_code_;
+  RawObject** to() {
+    return reinterpret_cast<RawObject**>(&ptr()->dependent_code_);
+  }
 
   intptr_t token_pos_;
+  intptr_t guarded_cid_;
+  intptr_t is_nullable_;  // kNullCid if field can contain null value and

[Ivan Posva, 2013/03/19 04:42:05]

As far as I understand this is a boolean value. Why not roll that into the
kind_bits_?

[Vyacheslav Egorov (Google), 2013/03/19 06:58:59]

Having a boolean complicates checking and initialization in the generated code,
for the case when field does not have a feedback.

With a boolean I need to have additional control flow that decodes/encodes. With
cid here I just compare is_nullable_ to the cid of the value when comparison
with guarded_cid_ has failed. (and I just store value's cid when initializing it
initially). So the comment is somewhat incorrect. It can contain any other cid
if it is not null.

[Ivan Posva, 2013/03/19 15:48:51]

In that case please update the comment.

[Vyacheslav Egorov (Google), 2013/03/19 19:57:50]

Done.

+                          // kIllegalCid otherwise.
   uint8_t kind_bits_;  // static, final, const, has initializer.
 };
 
 
 class RawLiteralToken : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(LiteralToken);
 
   RawObject** from() {
     return reinterpret_cast<RawObject**>(&ptr()->literal_);
   }
@@ skipping 1195 matching lines @@
 inline intptr_t RawObject::NumberOfTypedDataClasses() {
   // Make sure this is updated when new TypedData types are added.
   ASSERT(kExternalTypedDataInt8ArrayCid == kTypedDataInt8ArrayCid + 11);
   ASSERT(kNullCid == kExternalTypedDataInt8ArrayCid + 11);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_