Make --noopt behave like an in-place precompilation.

runtime/vm/precompiler.cc

 // Copyright (c) 2015, 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/precompiler.h"
 
 #include "vm/compiler.h"
 #include "vm/isolate.h"
 #include "vm/log.h"
 #include "vm/longjump.h"
@@ skipping 11 matching lines @@
 
 DEFINE_FLAG(bool, trace_precompiler, false, "Trace precompiler.");
 
 
 static void Jump(const Error& error) {
   Thread::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 RawError* Precompiler::CompileAll(
-    Dart_QualifiedFunctionName embedder_entry_points[]) {
+    Dart_QualifiedFunctionName embedder_entry_points[],
+    bool reset_fields) {
   LongJumpScope jump;
   if (setjmp(*jump.Set()) == 0) {
-    Precompiler precompiler(Thread::Current());
+    Precompiler precompiler(Thread::Current(), reset_fields);
     precompiler.DoCompileAll(embedder_entry_points);
     return Error::null();
   } else {
     Isolate* isolate = Isolate::Current();
     const Error& error = Error::Handle(isolate->object_store()->sticky_error());
     isolate->object_store()->clear_sticky_error();
     return error.raw();
   }
 }
 
 
-Precompiler::Precompiler(Thread* thread) :
+Precompiler::Precompiler(Thread* thread, bool reset_fields) :
   thread_(thread),
   zone_(thread->zone()),
   isolate_(thread->isolate()),
+  reset_fields_(reset_fields),
   changed_(false),
   function_count_(0),
   class_count_(0),
   selector_count_(0),
   dropped_function_count_(0),
   libraries_(GrowableObjectArray::Handle(Z, I->object_store()->libraries())),
   pending_functions_(GrowableObjectArray::Handle(Z,
                                                  GrowableObjectArray::New())),
   collected_closures_(GrowableObjectArray::Handle(Z, I->collected_closures())),
   sent_selectors_(Z),
@@ skipping 375 matching lines @@
 
 void Precompiler::AddField(const Field& field) {
   if (field.is_static()) {
     // Potential const object. Uninitialized field will harmlessly do a
     // redundant add of the Null class.
     const Object& value = Object::Handle(Z, field.StaticValue());
     const Class& cls = Class::Handle(Z, value.clazz());
     AddClass(cls);
 
     if (field.has_initializer()) {
+      // Should not be in the middle of initialization while precompiling.
+      ASSERT(value.raw() != Object::transition_sentinel().raw());
+
+      const bool is_initialized = value.raw() != Object::sentinel().raw();
+      if (is_initialized && !reset_fields_) return;
+
       if (field.HasPrecompiledInitializer()) return;
 
       if (FLAG_trace_precompiler) {
         THR_Print("Precompiling initializer for %s\n", field.ToCString());
       }
       ASSERT(!Dart::IsRunningPrecompiledCode());
       field.SetStaticValue(Instance::Handle(field.SavedInitialStaticValue()));
       Compiler::CompileStaticInitializer(field);
 
       const Function& function =
@@ skipping 221 matching lines @@
         for (intptr_t j = 0; j < closures.Length(); j++) {
           function ^= closures.At(j);
           ASSERT(function.HasCode());
         }
       }
     }
   }
 }
 
 }  // namespace dart