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

runtime/vm/assembler_arm.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_ARM)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/longjump.h"
@@ skipping 1547 matching lines @@
 }
 
 
 void Assembler::LoadIsolate(Register rd) {
   ldr(rd, Address(THR, Thread::isolate_offset()));
 }
 
 
 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;
   }
 
   ASSERT(object.IsNotTemporaryScopedHandle());
   ASSERT(object.IsOld());
   return true;
 }
 
 
 void Assembler::LoadObjectHelper(Register rd,
                                  const Object& object,
                                  Condition cond,
                                  bool is_unique,
                                  Register pp) {
   ASSERT(!object.IsICData() || ICData::Cast(object).IsOriginal());
+  ASSERT(!object.IsField() || Field::Cast(object).IsOriginal());
   // Load common VM constants from the thread. This works also in places where
   // no constant pool is set up (e.g. intrinsic code).
   if (Thread::CanLoadFromThread(object)) {
     // Load common VM constants from the thread. This works also in places where
     // no constant pool is set up (e.g. intrinsic code).
     ldr(rd, Address(THR, Thread::OffsetFromThread(object)), cond);
   } else if (object.IsSmi()) {
     // Relocation doesn't apply to Smis.
     LoadImmediate(rd, reinterpret_cast<int32_t>(object.raw()), cond);
   } else if (CanLoadFromObjectPool(object)) {
@@ skipping 39 matching lines @@
                                 Patchability patchable,
                                 Condition cond) {
   const int32_t offset = ObjectPool::element_offset(
       object_pool_wrapper_.FindNativeEntry(label, patchable));
   LoadWordFromPoolOffset(rd, offset - kHeapObjectTag, PP, cond);
 }
 
 
 void Assembler::PushObject(const Object& object) {
   ASSERT(!object.IsICData() || ICData::Cast(object).IsOriginal());
+  ASSERT(!object.IsField() || Field::Cast(object).IsOriginal());
   LoadObject(IP, object);
   Push(IP);
 }
 
 
 void Assembler::CompareObject(Register rn, const Object& object) {
   ASSERT(!object.IsICData() || ICData::Cast(object).IsOriginal());
+  ASSERT(!object.IsField() || Field::Cast(object).IsOriginal());
   ASSERT(rn != IP);
   if (object.IsSmi()) {
     CompareImmediate(rn, reinterpret_cast<int32_t>(object.raw()));
   } else {
     LoadObject(IP, object);
     cmp(rn, Operand(IP));
   }
 }
 
 
@@ skipping 239 matching lines @@
     StoreIntoObjectNoBarrier(object, Address(IP), value, old_content);
   }
 }
 
 
 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());
   ASSERT(value.IsSmi() || value.InVMHeap() ||
          (value.IsOld() && value.IsNotTemporaryScopedHandle()));
   // No store buffer update.
   LoadObject(IP, value);
   VerifiedWrite(object, dest, IP, old_content);
 }
 
 
 void Assembler::StoreIntoObjectNoBarrierOffset(Register object,
                                                int32_t offset,
                                                const Object& value,
                                                FieldContent old_content) {
   ASSERT(!value.IsICData() || ICData::Cast(value).IsOriginal());
+  ASSERT(!value.IsField() || Field::Cast(value).IsOriginal());
   int32_t ignored = 0;
   if (Address::CanHoldStoreOffset(kWord, offset - kHeapObjectTag, &ignored)) {
     StoreIntoObjectNoBarrier(object, FieldAddress(object, offset), value,
                              old_content);
   } else {
     Register base = object == R9 ? R8 : R9;
     Push(base);
     AddImmediate(base, object, offset - kHeapObjectTag);
     StoreIntoObjectNoBarrier(object, Address(base), value, old_content);
     Pop(base);
@@ skipping 1746 matching lines @@
 
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfFpuRegisters));
   return fpu_reg_names[reg];
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM