In background compilation make a copy of Field in order to freeze its state

runtime/vm/assembler_x64.cc

 // Copyright (c) 2013, 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"  // NOLINT
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/heap.h"
@@ skipping 2731 matching lines @@
       popq(tmp);
     }
     return;
   }
   addq(RSP, Immediate(stack_elements * kWordSize));
 }
 
 
 bool Assembler::CanLoadFromObjectPool(const Object& object) const {
   ASSERT(!object.IsICData() || ICData::Cast(object).IsOriginal());
+  ASSERT(!object.IsField() || Field::Cast(object).IsOriginal());
   ASSERT(!Thread::CanLoadFromThread(object));
   if (!constant_pool_allowed()) {
     return false;
   }
 
   // TODO(zra, kmillikin): Also load other large immediates from the object
   // pool
   if (object.IsSmi()) {
     // If the raw smi does not fit into a 32-bit signed int, then we'll keep
     // the raw value in the object pool.
@@ skipping 16 matching lines @@
 
 void Assembler::LoadIsolate(Register dst) {
   movq(dst, Address(THR, Thread::isolate_offset()));
 }
 
 
 void Assembler::LoadObjectHelper(Register dst,
                                  const Object& object,
                                  bool is_unique) {
   ASSERT(!object.IsICData() || ICData::Cast(object).IsOriginal());
+  ASSERT(!object.IsField() || Field::Cast(object).IsOriginal());
   if (Thread::CanLoadFromThread(object)) {
     movq(dst, Address(THR, Thread::OffsetFromThread(object)));
   } else if (CanLoadFromObjectPool(object)) {
     const int32_t offset = ObjectPool::element_offset(
         is_unique ? object_pool_wrapper_.AddObject(object)
                   : object_pool_wrapper_.FindObject(object));
     LoadWordFromPoolOffset(dst, offset - kHeapObjectTag);
   } else {
     ASSERT(object.IsSmi() || object.InVMHeap());
     ASSERT(object.IsSmi() || FLAG_allow_absolute_addresses);
@@ skipping 18 matching lines @@
 }
 
 
 void Assembler::LoadUniqueObject(Register dst, const Object& object) {
   LoadObjectHelper(dst, object, true);
 }
 
 
 void Assembler::StoreObject(const Address& dst, const Object& object) {
   ASSERT(!object.IsICData() || ICData::Cast(object).IsOriginal());
+  ASSERT(!object.IsField() || Field::Cast(object).IsOriginal());
   if (Thread::CanLoadFromThread(object)) {
     movq(TMP, Address(THR, Thread::OffsetFromThread(object)));
     movq(dst, TMP);
   } else if (CanLoadFromObjectPool(object)) {
     LoadObject(TMP, object);
     movq(dst, TMP);
   } else {
     ASSERT(object.IsSmi() || FLAG_allow_absolute_addresses);
     MoveImmediate(dst, Immediate(reinterpret_cast<int64_t>(object.raw())));
   }
 }
 
 
 void Assembler::PushObject(const Object& object) {
   ASSERT(!object.IsICData() || ICData::Cast(object).IsOriginal());
+  ASSERT(!object.IsField() || Field::Cast(object).IsOriginal());
   if (Thread::CanLoadFromThread(object)) {
     pushq(Address(THR, Thread::OffsetFromThread(object)));
   } else if (CanLoadFromObjectPool(object)) {
     LoadObject(TMP, object);
     pushq(TMP);
   } else {
     ASSERT(object.IsSmi() || FLAG_allow_absolute_addresses);
     PushImmediate(Immediate(reinterpret_cast<int64_t>(object.raw())));
   }
 }
 
 
 void Assembler::CompareObject(Register reg, const Object& object) {
   ASSERT(!object.IsICData() || ICData::Cast(object).IsOriginal());
+  ASSERT(!object.IsField() || Field::Cast(object).IsOriginal());
   if (Thread::CanLoadFromThread(object)) {
     cmpq(reg, Address(THR, Thread::OffsetFromThread(object)));
   } else if (CanLoadFromObjectPool(object)) {
     const int32_t offset =
         ObjectPool::element_offset(object_pool_wrapper_.FindObject(object));
     cmpq(reg, Address(PP, offset-kHeapObjectTag));
   } else {
     ASSERT(object.IsSmi() || FLAG_allow_absolute_addresses);
     CompareImmediate(
         reg, Immediate(reinterpret_cast<int64_t>(object.raw())));
@@ skipping 207 matching lines @@
 #endif  // defined(DEBUG)
   // No store buffer update.
 }
 
 
 void Assembler::StoreIntoObjectNoBarrier(Register object,
                                          const Address& dest,
                                          const Object& value,
                                          FieldContent old_content) {
   ASSERT(!value.IsICData() || ICData::Cast(value).IsOriginal());
+  ASSERT(!value.IsField() || Field::Cast(value).IsOriginal());
   VerifyHeapWord(dest, old_content);
   if (VerifiedMemory::enabled()) {
     const Register temp = RCX;
     pushq(temp);
     leaq(temp, dest);
     StoreObject(Address(temp, 0), value);
     StoreObject(Address(temp, VerifiedMemory::offset()), value);
     popq(temp);
   } else {
     StoreObject(dest, value);
@@ skipping 843 matching lines @@
 
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfXmmRegisters));
   return xmm_reg_names[reg];
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64