diff --git a/compiler/image_writer.h b/compiler/image_writer.h
index e8bcf7f..bdf0614 100644
--- a/compiler/image_writer.h
+++ b/compiler/image_writer.h
@@ -37,17 +37,39 @@
 // Write a Space built during compilation for use during execution.
 class ImageWriter {
  public:
-  explicit ImageWriter(const CompilerDriver& compiler_driver)
-      : compiler_driver_(compiler_driver), oat_file_(NULL), image_end_(0), image_begin_(NULL),
+  ImageWriter(const CompilerDriver& compiler_driver, uintptr_t image_begin)
+      : compiler_driver_(compiler_driver), image_begin_(reinterpret_cast<byte*>(image_begin)),
+        image_end_(0), image_roots_address_(0), oat_file_(NULL),
         oat_data_begin_(NULL), interpreter_to_interpreter_bridge_offset_(0),
-        interpreter_to_compiled_code_bridge_offset_(0), portable_imt_conflict_trampoline_offset_(0),
-        portable_resolution_trampoline_offset_(0), quick_generic_jni_trampoline_offset_(0),
-        quick_imt_conflict_trampoline_offset_(0), quick_resolution_trampoline_offset_(0) {}
+        interpreter_to_compiled_code_bridge_offset_(0), jni_dlsym_lookup_offset_(0),
+        portable_imt_conflict_trampoline_offset_(0), portable_resolution_trampoline_offset_(0),
+        portable_to_interpreter_bridge_offset_(0), quick_generic_jni_trampoline_offset_(0),
+        quick_imt_conflict_trampoline_offset_(0), quick_resolution_trampoline_offset_(0),
+        quick_to_interpreter_bridge_offset_(0) {
+    CHECK_NE(image_begin, 0U);
+  }
 
   ~ImageWriter() {}
 
+  bool PrepareImageAddressSpace();
+
+  bool IsImageAddressSpaceReady() const {
+    return image_roots_address_ != 0u;
+  }
+
+  mirror::Object* GetImageAddress(mirror::Object* object) const
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    if (object == NULL) {
+      return NULL;
+    }
+    return reinterpret_cast<mirror::Object*>(image_begin_ + GetImageOffset(object));
+  }
+
+  byte* GetOatFileBegin() const {
+    return image_begin_ + RoundUp(image_end_, kPageSize);
+  }
+
   bool Write(const std::string& image_filename,
-             uintptr_t image_begin,
              const std::string& oat_filename,
              const std::string& oat_location)
       LOCKS_EXCLUDED(Locks::mutator_lock_);
@@ -75,14 +97,6 @@
     return reinterpret_cast<ImageWriter*>(writer)->GetImageAddress(obj);
   }
 
-  mirror::Object* GetImageAddress(mirror::Object* object) const
-      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    if (object == NULL) {
-      return NULL;
-    }
-    return reinterpret_cast<mirror::Object*>(image_begin_ + GetImageOffset(object));
-  }
-
   mirror::Object* GetLocalAddress(mirror::Object* object) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     size_t offset = GetImageOffset(object);
@@ -131,7 +145,9 @@
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   // Lays out where the image objects will be at runtime.
-  void CalculateNewObjectOffsets(size_t oat_loaded_size, size_t oat_data_offset)
+  void CalculateNewObjectOffsets()
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  void CreateHeader(size_t oat_loaded_size, size_t oat_data_offset)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   mirror::ObjectArray<mirror::Object>* CreateImageRoots() const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -162,23 +178,25 @@
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   // Patches references in OatFile to expect runtime addresses.
-  void PatchOatCodeAndMethods(File* elf_file)
-      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  void SetOatChecksumFromElfFile(File* elf_file);
 
   const CompilerDriver& compiler_driver_;
 
+  // Beginning target image address for the output image.
+  byte* image_begin_;
+
+  // Offset to the free space in image_.
+  size_t image_end_;
+
+  // The image roots address in the image.
+  uint32_t image_roots_address_;
+
   // oat file with code for this image
   OatFile* oat_file_;
 
   // Memory mapped for generating the image.
   std::unique_ptr<MemMap> image_;
 
-  // Offset to the free space in image_.
-  size_t image_end_;
-
-  // Beginning target image address for the output image.
-  byte* image_begin_;
-
   // Saved hashes (objects are inside of the image so that they don't move).
   std::vector<std::pair<mirror::Object*, uint32_t>> saved_hashes_;