diff --git a/compiler/image_writer.cc b/compiler/image_writer.cc
new file mode 100644
index 0000000..8d32a91
--- /dev/null
+++ b/compiler/image_writer.cc
@@ -0,0 +1,680 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "image_writer.h"
+
+#include <sys/stat.h>
+
+#include <vector>
+
+#include "base/logging.h"
+#include "base/unix_file/fd_file.h"
+#include "class_linker.h"
+#include "compiled_method.h"
+#include "dex_file-inl.h"
+#include "driver/compiler_driver.h"
+#include "elf_writer.h"
+#include "gc/accounting/card_table-inl.h"
+#include "gc/accounting/heap_bitmap.h"
+#include "gc/heap.h"
+#include "gc/space/large_object_space.h"
+#include "gc/space/space-inl.h"
+#include "globals.h"
+#include "image.h"
+#include "intern_table.h"
+#include "mirror/array-inl.h"
+#include "mirror/class-inl.h"
+#include "mirror/class_loader.h"
+#include "mirror/dex_cache-inl.h"
+#include "mirror/field-inl.h"
+#include "mirror/abstract_method-inl.h"
+#include "mirror/object-inl.h"
+#include "mirror/object_array-inl.h"
+#include "oat.h"
+#include "oat_file.h"
+#include "object_utils.h"
+#include "runtime.h"
+#include "scoped_thread_state_change.h"
+#include "sirt_ref.h"
+#include "UniquePtr.h"
+#include "utils.h"
+
+using namespace art::mirror;
+
+namespace art {
+
+bool ImageWriter::Write(const std::string& image_filename,
+                        uintptr_t image_begin,
+                        const std::string& oat_filename,
+                        const std::string& oat_location) {
+  CHECK(!image_filename.empty());
+
+  CHECK_NE(image_begin, 0U);
+  image_begin_ = reinterpret_cast<byte*>(image_begin);
+
+  ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
+  const std::vector<DexCache*>& all_dex_caches = class_linker->GetDexCaches();
+  for (size_t i = 0; i < all_dex_caches.size(); i++) {
+    DexCache* dex_cache = all_dex_caches[i];
+    dex_caches_.insert(dex_cache);
+  }
+
+  UniquePtr<File> oat_file(OS::OpenFile(oat_filename.c_str(), true, false));
+  if (oat_file.get() == NULL) {
+    LOG(ERROR) << "Failed to open oat file " << oat_filename << " for " << oat_location;
+    return false;
+  }
+  oat_file_ = OatFile::OpenWritable(oat_file.get(), oat_location);
+  class_linker->RegisterOatFile(*oat_file_);
+  interpreter_to_interpreter_entry_offset_ = oat_file_->GetOatHeader().GetInterpreterToInterpreterEntryOffset();
+  interpreter_to_quick_entry_offset_ = oat_file_->GetOatHeader().GetInterpreterToQuickEntryOffset();
+  portable_resolution_trampoline_offset_ = oat_file_->GetOatHeader().GetPortableResolutionTrampolineOffset();
+  quick_resolution_trampoline_offset_ = oat_file_->GetOatHeader().GetQuickResolutionTrampolineOffset();
+
+  {
+    Thread::Current()->TransitionFromSuspendedToRunnable();
+    PruneNonImageClasses();  // Remove junk
+    ComputeLazyFieldsForImageClasses();  // Add useful information
+    ComputeEagerResolvedStrings();
+    Thread::Current()->TransitionFromRunnableToSuspended(kNative);
+  }
+  gc::Heap* heap = Runtime::Current()->GetHeap();
+  heap->CollectGarbage(false);  // Remove garbage.
+  // Trim size of alloc spaces.
+  const std::vector<gc::space::ContinuousSpace*>& spaces = heap->GetContinuousSpaces();
+  // TODO: C++0x auto
+  typedef std::vector<gc::space::ContinuousSpace*>::const_iterator It;
+  for (It it = spaces.begin(), end = spaces.end(); it != end; ++it) {
+    gc::space::ContinuousSpace* space = *it;
+    if (space->IsDlMallocSpace()) {
+      space->AsDlMallocSpace()->Trim();
+    }
+  }
+
+  if (!AllocMemory()) {
+    return false;
+  }
+#ifndef NDEBUG
+  {
+    ScopedObjectAccess soa(Thread::Current());
+    CheckNonImageClassesRemoved();
+  }
+#endif
+  Thread::Current()->TransitionFromSuspendedToRunnable();
+  size_t oat_loaded_size = 0;
+  size_t oat_data_offset = 0;
+  ElfWriter::GetOatElfInformation(oat_file.get(), oat_loaded_size, oat_data_offset);
+  CalculateNewObjectOffsets(oat_loaded_size, oat_data_offset);
+  CopyAndFixupObjects();
+  PatchOatCodeAndMethods();
+  Thread::Current()->TransitionFromRunnableToSuspended(kNative);
+
+  UniquePtr<File> image_file(OS::OpenFile(image_filename.c_str(), true));
+  if (image_file.get() == NULL) {
+    LOG(ERROR) << "Failed to open image file " << image_filename;
+    return false;
+  }
+  if (fchmod(image_file->Fd(), 0644) != 0) {
+    PLOG(ERROR) << "Failed to make image file world readable: " << image_filename;
+    return EXIT_FAILURE;
+  }
+  bool success = image_file->WriteFully(image_->Begin(), image_end_);
+  if (!success) {
+    PLOG(ERROR) << "Failed to write image file " << image_filename;
+    return false;
+  }
+  return true;
+}
+
+bool ImageWriter::AllocMemory() {
+  gc::Heap* heap = Runtime::Current()->GetHeap();
+  const std::vector<gc::space::ContinuousSpace*>& spaces = heap->GetContinuousSpaces();
+  size_t size = 0;
+  // TODO: C++0x auto
+  typedef std::vector<gc::space::ContinuousSpace*>::const_iterator It;
+  for (It it = spaces.begin(), end = spaces.end(); it != end; ++it) {
+    gc::space::ContinuousSpace* space = *it;
+    if (space->IsDlMallocSpace()) {
+      size += space->Size();
+    }
+  }
+
+  int prot = PROT_READ | PROT_WRITE;
+  size_t length = RoundUp(size, kPageSize);
+  image_.reset(MemMap::MapAnonymous("image writer image", NULL, length, prot));
+  if (image_.get() == NULL) {
+    LOG(ERROR) << "Failed to allocate memory for image file generation";
+    return false;
+  }
+  return true;
+}
+
+void ImageWriter::ComputeLazyFieldsForImageClasses() {
+  Runtime* runtime = Runtime::Current();
+  ClassLinker* class_linker = runtime->GetClassLinker();
+  class_linker->VisitClassesWithoutClassesLock(ComputeLazyFieldsForClassesVisitor, NULL);
+}
+
+bool ImageWriter::ComputeLazyFieldsForClassesVisitor(Class* c, void* /*arg*/) {
+  c->ComputeName();
+  return true;
+}
+
+void ImageWriter::ComputeEagerResolvedStringsCallback(Object* obj, void* arg) {
+  if (!obj->GetClass()->IsStringClass()) {
+    return;
+  }
+  String* string = obj->AsString();
+  const uint16_t* utf16_string = string->GetCharArray()->GetData() + string->GetOffset();
+  ImageWriter* writer = reinterpret_cast<ImageWriter*>(arg);
+  typedef Set::const_iterator CacheIt;  // TODO: C++0x auto
+  for (CacheIt it = writer->dex_caches_.begin(), end = writer->dex_caches_.end(); it != end; ++it) {
+    DexCache* dex_cache = *it;
+    const DexFile& dex_file = *dex_cache->GetDexFile();
+    const DexFile::StringId* string_id = dex_file.FindStringId(utf16_string);
+    if (string_id != NULL) {
+      // This string occurs in this dex file, assign the dex cache entry.
+      uint32_t string_idx = dex_file.GetIndexForStringId(*string_id);
+      if (dex_cache->GetResolvedString(string_idx) == NULL) {
+        dex_cache->SetResolvedString(string_idx, string);
+      }
+    }
+  }
+}
+
+void ImageWriter::ComputeEagerResolvedStrings()
+    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+  // TODO: Check image spaces only?
+  gc::Heap* heap = Runtime::Current()->GetHeap();
+  WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_);
+  heap->FlushAllocStack();
+  heap->GetLiveBitmap()->Walk(ComputeEagerResolvedStringsCallback, this);
+}
+
+bool ImageWriter::IsImageClass(const Class* klass) {
+  return compiler_driver_.IsImageClass(ClassHelper(klass).GetDescriptor());
+}
+
+struct NonImageClasses {
+  ImageWriter* image_writer;
+  std::set<std::string>* non_image_classes;
+};
+
+void ImageWriter::PruneNonImageClasses() {
+  if (compiler_driver_.GetImageClasses() == NULL) {
+    return;
+  }
+  Runtime* runtime = Runtime::Current();
+  ClassLinker* class_linker = runtime->GetClassLinker();
+
+  // Make a list of classes we would like to prune.
+  std::set<std::string> non_image_classes;
+  NonImageClasses context;
+  context.image_writer = this;
+  context.non_image_classes = &non_image_classes;
+  class_linker->VisitClasses(NonImageClassesVisitor, &context);
+
+  // Remove the undesired classes from the class roots.
+  typedef std::set<std::string>::const_iterator ClassIt;  // TODO: C++0x auto
+  for (ClassIt it = non_image_classes.begin(), end = non_image_classes.end(); it != end; ++it) {
+    class_linker->RemoveClass((*it).c_str(), NULL);
+  }
+
+  // Clear references to removed classes from the DexCaches.
+  AbstractMethod* resolution_method = runtime->GetResolutionMethod();
+  typedef Set::const_iterator CacheIt;  // TODO: C++0x auto
+  for (CacheIt it = dex_caches_.begin(), end = dex_caches_.end(); it != end; ++it) {
+    DexCache* dex_cache = *it;
+    for (size_t i = 0; i < dex_cache->NumResolvedTypes(); i++) {
+      Class* klass = dex_cache->GetResolvedType(i);
+      if (klass != NULL && !IsImageClass(klass)) {
+        dex_cache->SetResolvedType(i, NULL);
+        dex_cache->GetInitializedStaticStorage()->Set(i, NULL);
+      }
+    }
+    for (size_t i = 0; i < dex_cache->NumResolvedMethods(); i++) {
+      AbstractMethod* method = dex_cache->GetResolvedMethod(i);
+      if (method != NULL && !IsImageClass(method->GetDeclaringClass())) {
+        dex_cache->SetResolvedMethod(i, resolution_method);
+      }
+    }
+    for (size_t i = 0; i < dex_cache->NumResolvedFields(); i++) {
+      Field* field = dex_cache->GetResolvedField(i);
+      if (field != NULL && !IsImageClass(field->GetDeclaringClass())) {
+        dex_cache->SetResolvedField(i, NULL);
+      }
+    }
+  }
+}
+
+bool ImageWriter::NonImageClassesVisitor(Class* klass, void* arg) {
+  NonImageClasses* context = reinterpret_cast<NonImageClasses*>(arg);
+  if (!context->image_writer->IsImageClass(klass)) {
+    context->non_image_classes->insert(ClassHelper(klass).GetDescriptor());
+  }
+  return true;
+}
+
+void ImageWriter::CheckNonImageClassesRemoved()
+    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+  if (compiler_driver_.GetImageClasses() == NULL) {
+    return;
+  }
+
+  gc::Heap* heap = Runtime::Current()->GetHeap();
+  Thread* self = Thread::Current();
+  {
+    WriterMutexLock mu(self, *Locks::heap_bitmap_lock_);
+    heap->FlushAllocStack();
+  }
+
+  ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_);
+  heap->GetLiveBitmap()->Walk(CheckNonImageClassesRemovedCallback, this);
+}
+
+void ImageWriter::CheckNonImageClassesRemovedCallback(Object* obj, void* arg) {
+  ImageWriter* image_writer = reinterpret_cast<ImageWriter*>(arg);
+  if (!obj->IsClass()) {
+    return;
+  }
+  Class* klass = obj->AsClass();
+  if (!image_writer->IsImageClass(klass)) {
+    image_writer->DumpImageClasses();
+    CHECK(image_writer->IsImageClass(klass)) << ClassHelper(klass).GetDescriptor()
+                                             << " " << PrettyDescriptor(klass);
+  }
+}
+
+void ImageWriter::DumpImageClasses() {
+  CompilerDriver::DescriptorSet* image_classes = compiler_driver_.GetImageClasses();
+  CHECK(image_classes != NULL);
+  typedef std::set<std::string>::const_iterator It;  // TODO: C++0x auto
+  for (It it = image_classes->begin(), end = image_classes->end(); it != end; ++it) {
+    LOG(INFO) << " " << *it;
+  }
+}
+
+void ImageWriter::CalculateNewObjectOffsetsCallback(Object* obj, void* arg) {
+  DCHECK(obj != NULL);
+  DCHECK(arg != NULL);
+  ImageWriter* image_writer = reinterpret_cast<ImageWriter*>(arg);
+
+  // if it is a string, we want to intern it if its not interned.
+  if (obj->GetClass()->IsStringClass()) {
+    // we must be an interned string that was forward referenced and already assigned
+    if (image_writer->IsImageOffsetAssigned(obj)) {
+      DCHECK_EQ(obj, obj->AsString()->Intern());
+      return;
+    }
+    SirtRef<String> interned(Thread::Current(), obj->AsString()->Intern());
+    if (obj != interned.get()) {
+      if (!image_writer->IsImageOffsetAssigned(interned.get())) {
+        // interned obj is after us, allocate its location early
+        image_writer->AssignImageOffset(interned.get());
+      }
+      // point those looking for this object to the interned version.
+      image_writer->SetImageOffset(obj, image_writer->GetImageOffset(interned.get()));
+      return;
+    }
+    // else (obj == interned), nothing to do but fall through to the normal case
+  }
+
+  image_writer->AssignImageOffset(obj);
+}
+
+ObjectArray<Object>* ImageWriter::CreateImageRoots() const {
+  Runtime* runtime = Runtime::Current();
+  ClassLinker* class_linker = runtime->GetClassLinker();
+  Class* object_array_class = class_linker->FindSystemClass("[Ljava/lang/Object;");
+  Thread* self = Thread::Current();
+
+  // build an Object[] of all the DexCaches used in the source_space_
+  ObjectArray<Object>* dex_caches = ObjectArray<Object>::Alloc(self, object_array_class,
+                                                               dex_caches_.size());
+  int i = 0;
+  typedef Set::const_iterator It;  // TODO: C++0x auto
+  for (It it = dex_caches_.begin(), end = dex_caches_.end(); it != end; ++it, ++i) {
+    dex_caches->Set(i, *it);
+  }
+
+  // build an Object[] of the roots needed to restore the runtime
+  SirtRef<ObjectArray<Object> >
+      image_roots(self,
+                  ObjectArray<Object>::Alloc(self, object_array_class,
+                                             ImageHeader::kImageRootsMax));
+  image_roots->Set(ImageHeader::kResolutionMethod, runtime->GetResolutionMethod());
+  image_roots->Set(ImageHeader::kCalleeSaveMethod,
+                   runtime->GetCalleeSaveMethod(Runtime::kSaveAll));
+  image_roots->Set(ImageHeader::kRefsOnlySaveMethod,
+                   runtime->GetCalleeSaveMethod(Runtime::kRefsOnly));
+  image_roots->Set(ImageHeader::kRefsAndArgsSaveMethod,
+                   runtime->GetCalleeSaveMethod(Runtime::kRefsAndArgs));
+  image_roots->Set(ImageHeader::kOatLocation,
+                   String::AllocFromModifiedUtf8(self, oat_file_->GetLocation().c_str()));
+  image_roots->Set(ImageHeader::kDexCaches,
+                   dex_caches);
+  image_roots->Set(ImageHeader::kClassRoots,
+                   class_linker->GetClassRoots());
+  for (int i = 0; i < ImageHeader::kImageRootsMax; i++) {
+    CHECK(image_roots->Get(i) != NULL);
+  }
+  return image_roots.get();
+}
+
+void ImageWriter::CalculateNewObjectOffsets(size_t oat_loaded_size, size_t oat_data_offset) {
+  CHECK_NE(0U, oat_loaded_size);
+  Thread* self = Thread::Current();
+  SirtRef<ObjectArray<Object> > image_roots(self, CreateImageRoots());
+
+  gc::Heap* heap = Runtime::Current()->GetHeap();
+  const std::vector<gc::space::ContinuousSpace*>& spaces = heap->GetContinuousSpaces();
+  DCHECK(!spaces.empty());
+  DCHECK_EQ(0U, image_end_);
+
+  // leave space for the header, but do not write it yet, we need to
+  // know where image_roots is going to end up
+  image_end_ += RoundUp(sizeof(ImageHeader), 8); // 64-bit-alignment
+
+  {
+    WriterMutexLock mu(self, *Locks::heap_bitmap_lock_);
+    heap->FlushAllocStack();
+    // TODO: Image spaces only?
+    // TODO: Add InOrderWalk to heap bitmap.
+    const char* old = self->StartAssertNoThreadSuspension("ImageWriter");
+    DCHECK(heap->GetLargeObjectsSpace()->GetLiveObjects()->IsEmpty());
+    // TODO: C++0x auto
+    typedef std::vector<gc::space::ContinuousSpace*>::const_iterator It;
+    for (It it = spaces.begin(), end = spaces.end(); it != end; ++it) {
+      gc::space::ContinuousSpace* space = *it;
+      space->GetLiveBitmap()->InOrderWalk(CalculateNewObjectOffsetsCallback, this);
+      DCHECK_LT(image_end_, image_->Size());
+    }
+    self->EndAssertNoThreadSuspension(old);
+  }
+
+  const byte* oat_file_begin = image_begin_ + RoundUp(image_end_, kPageSize);
+  const byte* oat_file_end = oat_file_begin + oat_loaded_size;
+  oat_data_begin_ = oat_file_begin + oat_data_offset;
+  const byte* oat_data_end = oat_data_begin_ + oat_file_->Size();
+
+  // return to write header at start of image with future location of image_roots
+  ImageHeader image_header(reinterpret_cast<uint32_t>(image_begin_),
+                           reinterpret_cast<uint32_t>(GetImageAddress(image_roots.get())),
+                           oat_file_->GetOatHeader().GetChecksum(),
+                           reinterpret_cast<uint32_t>(oat_file_begin),
+                           reinterpret_cast<uint32_t>(oat_data_begin_),
+                           reinterpret_cast<uint32_t>(oat_data_end),
+                           reinterpret_cast<uint32_t>(oat_file_end));
+  memcpy(image_->Begin(), &image_header, sizeof(image_header));
+
+  // Note that image_end_ is left at end of used space
+}
+
+void ImageWriter::CopyAndFixupObjects()
+    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+  Thread* self = Thread::Current();
+  const char* old_cause = self->StartAssertNoThreadSuspension("ImageWriter");
+  gc::Heap* heap = Runtime::Current()->GetHeap();
+  // TODO: heap validation can't handle this fix up pass
+  heap->DisableObjectValidation();
+  // TODO: Image spaces only?
+  WriterMutexLock mu(self, *Locks::heap_bitmap_lock_);
+  heap->FlushAllocStack();
+  heap->GetLiveBitmap()->Walk(CopyAndFixupObjectsCallback, this);
+  self->EndAssertNoThreadSuspension(old_cause);
+}
+
+void ImageWriter::CopyAndFixupObjectsCallback(Object* object, void* arg) {
+  DCHECK(object != NULL);
+  DCHECK(arg != NULL);
+  const Object* obj = object;
+  ImageWriter* image_writer = reinterpret_cast<ImageWriter*>(arg);
+
+  // see GetLocalAddress for similar computation
+  size_t offset = image_writer->GetImageOffset(obj);
+  byte* dst = image_writer->image_->Begin() + offset;
+  const byte* src = reinterpret_cast<const byte*>(obj);
+  size_t n = obj->SizeOf();
+  DCHECK_LT(offset + n, image_writer->image_->Size());
+  memcpy(dst, src, n);
+  Object* copy = reinterpret_cast<Object*>(dst);
+  copy->SetField32(Object::MonitorOffset(), 0, false); // We may have inflated the lock during compilation.
+  image_writer->FixupObject(obj, copy);
+}
+
+void ImageWriter::FixupObject(const Object* orig, Object* copy) {
+  DCHECK(orig != NULL);
+  DCHECK(copy != NULL);
+  copy->SetClass(down_cast<Class*>(GetImageAddress(orig->GetClass())));
+  // TODO: special case init of pointers to malloc data (or removal of these pointers)
+  if (orig->IsClass()) {
+    FixupClass(orig->AsClass(), down_cast<Class*>(copy));
+  } else if (orig->IsObjectArray()) {
+    FixupObjectArray(orig->AsObjectArray<Object>(), down_cast<ObjectArray<Object>*>(copy));
+  } else if (orig->IsMethod()) {
+    FixupMethod(orig->AsMethod(), down_cast<AbstractMethod*>(copy));
+  } else {
+    FixupInstanceFields(orig, copy);
+  }
+}
+
+void ImageWriter::FixupClass(const Class* orig, Class* copy) {
+  FixupInstanceFields(orig, copy);
+  FixupStaticFields(orig, copy);
+}
+
+void ImageWriter::FixupMethod(const AbstractMethod* orig, AbstractMethod* copy) {
+  FixupInstanceFields(orig, copy);
+
+  // OatWriter replaces the code_ with an offset value.
+  // Here we readjust to a pointer relative to oat_begin_
+  if (orig->IsAbstract()) {
+    // Code for abstract methods is set to the abstract method error stub when we load the image.
+    copy->SetEntryPointFromCompiledCode(NULL);
+    copy->SetEntryPointFromInterpreter(reinterpret_cast<EntryPointFromInterpreter*>
+                                       (GetOatAddress(interpreter_to_interpreter_entry_offset_)));
+    return;
+  } else {
+    copy->SetEntryPointFromInterpreter(reinterpret_cast<EntryPointFromInterpreter*>
+                                       (GetOatAddress(interpreter_to_quick_entry_offset_)));
+  }
+
+  if (orig == Runtime::Current()->GetResolutionMethod()) {
+#if defined(ART_USE_PORTABLE_COMPILER)
+    copy->SetEntryPointFromCompiledCode(GetOatAddress(portable_resolution_trampoline_offset_));
+#else
+    copy->SetEntryPointFromCompiledCode(GetOatAddress(quick_resolution_trampoline_offset_));
+#endif
+    return;
+  }
+
+  // Use original code if it exists. Otherwise, set the code pointer to the resolution trampoline.
+  const byte* code = GetOatAddress(orig->GetOatCodeOffset());
+  if (code != NULL) {
+    copy->SetEntryPointFromCompiledCode(code);
+  } else {
+#if defined(ART_USE_PORTABLE_COMPILER)
+    copy->SetEntryPointFromCompiledCode(GetOatAddress(portable_resolution_trampoline_offset_));
+#else
+    copy->SetEntryPointFromCompiledCode(GetOatAddress(quick_resolution_trampoline_offset_));
+#endif
+  }
+
+  if (orig->IsNative()) {
+    // The native method's pointer is set to a stub to lookup via dlsym when we load the image.
+    // Note this is not the code_ pointer, that is handled above.
+    copy->SetNativeMethod(NULL);
+  } else {
+    // normal (non-abstract non-native) methods have mapping tables to relocate
+    uint32_t mapping_table_off = orig->GetOatMappingTableOffset();
+    const byte* mapping_table = GetOatAddress(mapping_table_off);
+    copy->SetMappingTable(reinterpret_cast<const uint32_t*>(mapping_table));
+
+    uint32_t vmap_table_offset = orig->GetOatVmapTableOffset();
+    const byte* vmap_table = GetOatAddress(vmap_table_offset);
+    copy->SetVmapTable(reinterpret_cast<const uint16_t*>(vmap_table));
+
+    uint32_t native_gc_map_offset = orig->GetOatNativeGcMapOffset();
+    const byte* native_gc_map = GetOatAddress(native_gc_map_offset);
+    copy->SetNativeGcMap(reinterpret_cast<const uint8_t*>(native_gc_map));
+  }
+}
+
+void ImageWriter::FixupObjectArray(const ObjectArray<Object>* orig, ObjectArray<Object>* copy) {
+  for (int32_t i = 0; i < orig->GetLength(); ++i) {
+    const Object* element = orig->Get(i);
+    copy->SetPtrWithoutChecks(i, GetImageAddress(element));
+  }
+}
+
+void ImageWriter::FixupInstanceFields(const Object* orig, Object* copy) {
+  DCHECK(orig != NULL);
+  DCHECK(copy != NULL);
+  Class* klass = orig->GetClass();
+  DCHECK(klass != NULL);
+  FixupFields(orig,
+              copy,
+              klass->GetReferenceInstanceOffsets(),
+              false);
+}
+
+void ImageWriter::FixupStaticFields(const Class* orig, Class* copy) {
+  DCHECK(orig != NULL);
+  DCHECK(copy != NULL);
+  FixupFields(orig,
+              copy,
+              orig->GetReferenceStaticOffsets(),
+              true);
+}
+
+void ImageWriter::FixupFields(const Object* orig,
+                              Object* copy,
+                              uint32_t ref_offsets,
+                              bool is_static) {
+  if (ref_offsets != CLASS_WALK_SUPER) {
+    // Found a reference offset bitmap.  Fixup the specified offsets.
+    while (ref_offsets != 0) {
+      size_t right_shift = CLZ(ref_offsets);
+      MemberOffset byte_offset = CLASS_OFFSET_FROM_CLZ(right_shift);
+      const Object* ref = orig->GetFieldObject<const Object*>(byte_offset, false);
+      // Use SetFieldPtr to avoid card marking since we are writing to the image.
+      copy->SetFieldPtr(byte_offset, GetImageAddress(ref), false);
+      ref_offsets &= ~(CLASS_HIGH_BIT >> right_shift);
+    }
+  } else {
+    // There is no reference offset bitmap.  In the non-static case,
+    // walk up the class inheritance hierarchy and find reference
+    // offsets the hard way. In the static case, just consider this
+    // class.
+    for (const Class *klass = is_static ? orig->AsClass() : orig->GetClass();
+         klass != NULL;
+         klass = is_static ? NULL : klass->GetSuperClass()) {
+      size_t num_reference_fields = (is_static
+                                     ? klass->NumReferenceStaticFields()
+                                     : klass->NumReferenceInstanceFields());
+      for (size_t i = 0; i < num_reference_fields; ++i) {
+        Field* field = (is_static
+                        ? klass->GetStaticField(i)
+                        : klass->GetInstanceField(i));
+        MemberOffset field_offset = field->GetOffset();
+        const Object* ref = orig->GetFieldObject<const Object*>(field_offset, false);
+        // Use SetFieldPtr to avoid card marking since we are writing to the image.
+        copy->SetFieldPtr(field_offset, GetImageAddress(ref), false);
+      }
+    }
+  }
+  if (!is_static && orig->IsReferenceInstance()) {
+    // Fix-up referent, that isn't marked as an object field, for References.
+    Field* field = orig->GetClass()->FindInstanceField("referent", "Ljava/lang/Object;");
+    MemberOffset field_offset = field->GetOffset();
+    const Object* ref = orig->GetFieldObject<const Object*>(field_offset, false);
+    // Use SetFieldPtr to avoid card marking since we are writing to the image.
+    copy->SetFieldPtr(field_offset, GetImageAddress(ref), false);
+  }
+}
+
+static AbstractMethod* GetTargetMethod(const CompilerDriver::PatchInformation* patch)
+    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+  ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
+  DexCache* dex_cache = class_linker->FindDexCache(patch->GetDexFile());
+  AbstractMethod* method = class_linker->ResolveMethod(patch->GetDexFile(),
+                                               patch->GetTargetMethodIdx(),
+                                               dex_cache,
+                                               NULL,
+                                               NULL,
+                                               patch->GetTargetInvokeType());
+  CHECK(method != NULL)
+    << patch->GetDexFile().GetLocation() << " " << patch->GetTargetMethodIdx();
+  CHECK(!method->IsRuntimeMethod())
+    << patch->GetDexFile().GetLocation() << " " << patch->GetTargetMethodIdx();
+  CHECK(dex_cache->GetResolvedMethods()->Get(patch->GetTargetMethodIdx()) == method)
+    << patch->GetDexFile().GetLocation() << " " << patch->GetReferrerMethodIdx() << " "
+    << PrettyMethod(dex_cache->GetResolvedMethods()->Get(patch->GetTargetMethodIdx())) << " "
+    << PrettyMethod(method);
+  return method;
+}
+
+void ImageWriter::PatchOatCodeAndMethods() {
+  Thread* self = Thread::Current();
+  ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
+  const char* old_cause = self->StartAssertNoThreadSuspension("ImageWriter");
+
+  typedef std::vector<const CompilerDriver::PatchInformation*> Patches;
+  const Patches& code_to_patch = compiler_driver_.GetCodeToPatch();
+  for (size_t i = 0; i < code_to_patch.size(); i++) {
+    const CompilerDriver::PatchInformation* patch = code_to_patch[i];
+    AbstractMethod* target = GetTargetMethod(patch);
+    uint32_t code = reinterpret_cast<uint32_t>(class_linker->GetOatCodeFor(target));
+    uint32_t code_base = reinterpret_cast<uint32_t>(&oat_file_->GetOatHeader());
+    uint32_t code_offset = code - code_base;
+    SetPatchLocation(patch, reinterpret_cast<uint32_t>(GetOatAddress(code_offset)));
+  }
+
+  const Patches& methods_to_patch = compiler_driver_.GetMethodsToPatch();
+  for (size_t i = 0; i < methods_to_patch.size(); i++) {
+    const CompilerDriver::PatchInformation* patch = methods_to_patch[i];
+    AbstractMethod* target = GetTargetMethod(patch);
+    SetPatchLocation(patch, reinterpret_cast<uint32_t>(GetImageAddress(target)));
+  }
+
+  // Update the image header with the new checksum after patching
+  ImageHeader* image_header = reinterpret_cast<ImageHeader*>(image_->Begin());
+  image_header->SetOatChecksum(oat_file_->GetOatHeader().GetChecksum());
+  self->EndAssertNoThreadSuspension(old_cause);
+}
+
+void ImageWriter::SetPatchLocation(const CompilerDriver::PatchInformation* patch, uint32_t value) {
+  ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
+  const void* oat_code = class_linker->GetOatCodeFor(patch->GetDexFile(),
+                                                     patch->GetReferrerMethodIdx());
+  OatHeader& oat_header = const_cast<OatHeader&>(oat_file_->GetOatHeader());
+  // TODO: make this Thumb2 specific
+  uint8_t* base = reinterpret_cast<uint8_t*>(reinterpret_cast<uint32_t>(oat_code) & ~0x1);
+  uint32_t* patch_location = reinterpret_cast<uint32_t*>(base + patch->GetLiteralOffset());
+#ifndef NDEBUG
+  const DexFile::MethodId& id = patch->GetDexFile().GetMethodId(patch->GetTargetMethodIdx());
+  uint32_t expected = reinterpret_cast<uint32_t>(&id);
+  uint32_t actual = *patch_location;
+  CHECK(actual == expected || actual == value) << std::hex
+    << "actual=" << actual
+    << "expected=" << expected
+    << "value=" << value;
+#endif
+  *patch_location = value;
+  oat_header.UpdateChecksum(patch_location, sizeof(value));
+}
+
+}  // namespace art