Collect type feedback for fields.

runtime/vm/object.h

Index: runtime/vm/object.h
diff --git a/runtime/vm/object.h b/runtime/vm/object.h
index 2510404a9de0d8e11a38dc484b0630e2b28bad16..eba9703d28782443c61faae70ab1f4447f32e261 100644
--- a/runtime/vm/object.h
+++ b/runtime/vm/object.h
@@ -1775,6 +1775,39 @@ class Field : public Object {
                                             raw_ptr()->kind_bits_));
   }
 
+  intptr_t GuardedCid() const {
+    if (is_nullable() && guarded_cid() != kNullCid) {
+      return kDynamicCid;
+    }
+    return raw_ptr()->guarded_cid_;
+  }
+
+  intptr_t guarded_cid() const { return raw_ptr()->guarded_cid_; }
+  void set_guarded_cid(intptr_t cid) const {
+    raw_ptr()->guarded_cid_ = cid;
+  }
+  static intptr_t guarded_cid_offset() {
+    return OFFSET_OF(RawField, guarded_cid_);
+  }
+
+  bool is_nullable() const {
+    return raw_ptr()->is_nullable_ == kNullCid;
+  }
+  void set_is_nullable(bool val) const {
+    raw_ptr()->is_nullable_ = val ? kNullCid : kIllegalCid;
+  }
+  static intptr_t is_nullable_offset() {
+    return OFFSET_OF(RawField, is_nullable_);
+  }
+
+  RawArray* dependent_code() const;
+  void set_dependent_code(const Array& array) const;
+  void RegisterDependentCode(const Code& code) const;
+  void UnregisterDependentCode(const Code& code) const;
+  void DeoptimizeDependentCode() const;
+  void UpdateCid(intptr_t cid) const;
+
+
   // Constructs getter and setter names for fields and vice versa.
   static RawString* GetterName(const String& field_name);
   static RawString* GetterSymbol(const String& field_name);
@@ -4650,6 +4683,9 @@ class Array : public Instance {
   }
   static intptr_t length_offset() { return OFFSET_OF(RawArray, length_); }
   static intptr_t data_offset() { return length_offset() + kWordSize; }
+  static intptr_t element_offset(intptr_t index) {
+    return data_offset() + kWordSize * index;
+  }
 
   RawObject* At(intptr_t index) const {
     return *ObjectAddr(index);