VM: [Kernel] Set DoubleInitializedBit on fields with double initializers.

runtime/vm/kernel_reader.cc

 // Copyright (c) 2016, 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/kernel_reader.h"
 
 #include <string.h>
 
 #include "vm/dart_api_impl.h"
 #include "vm/longjump.h"
@@ skipping 544 matching lines @@
     array_object ^= AsSortedDuplicateFreeArray(
         source_uri_index, &program_->yield_token_positions);
     script.set_yield_positions(array_object);
   }
   return script;
 }
 
 void KernelReader::GenerateFieldAccessors(const dart::Class& klass,
                                           const dart::Field& field,
                                           Field* kernel_field) {
-  if (kernel_field->IsStatic() && kernel_field->initializer() != NULL) {
-    // Static fields with initializers either have the static value set to the
-    // initializer value if it is simple enough or else set to an uninitialized
-    // sentinel.
+  if (kernel_field->initializer() != NULL) {
     SimpleExpressionConverter converter(H.thread());
-    if (converter.IsSimple(kernel_field->initializer())) {
-      // We do not need a getter.
-      field.SetStaticValue(converter.SimpleValue(), true);
-      return;
+    const bool has_simple_initializer =
+        converter.IsSimple(kernel_field->initializer());
+    if (kernel_field->IsStatic()) {
+      // Static fields with initializers either have the static value set to the
+      // initializer value if it is simple enough or else set to an
+      // uninitialized sentinel.
+      if (has_simple_initializer) {
+        // We do not need a getter.
+        field.SetStaticValue(converter.SimpleValue(), true);
+        return;
+      }
+      // We do need a getter that evaluates the initializer if necessary.
+      field.SetStaticValue(Object::sentinel(), true);
+    } else if (has_simple_initializer) {
+      field.RecordStore(converter.SimpleValue());
+      if (!converter.SimpleValue().IsNull() &&
+          converter.SimpleValue().IsDouble()) {
+        field.set_is_double_initialized(true);

[erikcorry, 2017/03/07 12:32:50]

Comment suggestion:
The field is initialized with a simple floating point value.
Emulate C++ parser by setting flag on field that helps the optimizer.

[Vyacheslav Egorov (Google), 2017/03/07 13:44:25]

Added a comment

+      }
     }
-    // We do need a getter that evaluates the initializer if necessary.
-    field.SetStaticValue(Object::sentinel(), true);
   }
 
   const dart::String& getter_name = H.DartGetterName(kernel_field->name());
   const Object& script_class =
       ClassForScriptAt(klass, kernel_field->source_uri_index());
   Function& getter = Function::ZoneHandle(
       Z,
       Function::New(
           getter_name,
           kernel_field->IsStatic() ? RawFunction::kImplicitStaticFinalGetter
@@ skipping 231 matching lines @@
   initializer_fun.set_is_debuggable(false);
   initializer_fun.set_is_reflectable(false);
   initializer_fun.set_is_inlinable(false);
   return new (zone) ParsedFunction(thread, initializer_fun);
 }
 
 
 }  // namespace kernel
 }  // namespace dart
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)