diff --git a/compiler/driver/compiler_driver.h b/compiler/driver/compiler_driver.h
index 1347b37..5c5a63d 100644
--- a/compiler/driver/compiler_driver.h
+++ b/compiler/driver/compiler_driver.h
@@ -161,16 +161,11 @@
   }
 
   // Generate the trampolines that are invoked by unresolved direct methods.
-  const std::vector<uint8_t>* CreateJniDlsymLookup() const
-      SHARED_REQUIRES(Locks::mutator_lock_);
-  const std::vector<uint8_t>* CreateQuickGenericJniTrampoline() const
-      SHARED_REQUIRES(Locks::mutator_lock_);
-  const std::vector<uint8_t>* CreateQuickImtConflictTrampoline() const
-      SHARED_REQUIRES(Locks::mutator_lock_);
-  const std::vector<uint8_t>* CreateQuickResolutionTrampoline() const
-      SHARED_REQUIRES(Locks::mutator_lock_);
-  const std::vector<uint8_t>* CreateQuickToInterpreterBridge() const
-      SHARED_REQUIRES(Locks::mutator_lock_);
+  const std::vector<uint8_t>* CreateJniDlsymLookup() const;
+  const std::vector<uint8_t>* CreateQuickGenericJniTrampoline() const;
+  const std::vector<uint8_t>* CreateQuickImtConflictTrampoline() const;
+  const std::vector<uint8_t>* CreateQuickResolutionTrampoline() const;
+  const std::vector<uint8_t>* CreateQuickToInterpreterBridge() const;
 
   CompiledClass* GetCompiledClass(ClassReference ref) const
       REQUIRES(!compiled_classes_lock_);
diff --git a/compiler/image_test.cc b/compiler/image_test.cc
index cda6240..c3a31ca 100644
--- a/compiler/image_test.cc
+++ b/compiler/image_test.cc
@@ -113,14 +113,9 @@
       elf_writer->EndText(text);
 
       elf_writer->SetBssSize(oat_writer.GetBssSize());
-
       elf_writer->WriteDynamicSection();
-
-      ArrayRef<const dwarf::MethodDebugInfo> method_infos(oat_writer.GetMethodDebugInfo());
-      elf_writer->WriteDebugInfo(method_infos);
-
-      ArrayRef<const uintptr_t> patch_locations(oat_writer.GetAbsolutePatchLocations());
-      elf_writer->WritePatchLocations(patch_locations);
+      elf_writer->WriteDebugInfo(oat_writer.GetMethodDebugInfo());
+      elf_writer->WritePatchLocations(oat_writer.GetAbsolutePatchLocations());
 
       success = elf_writer->End();
 
diff --git a/compiler/oat_test.cc b/compiler/oat_test.cc
index b8610d0..f995cd7 100644
--- a/compiler/oat_test.cc
+++ b/compiler/oat_test.cc
@@ -157,14 +157,9 @@
     elf_writer->EndText(text);
 
     elf_writer->SetBssSize(oat_writer.GetBssSize());
-
     elf_writer->WriteDynamicSection();
-
-    ArrayRef<const dwarf::MethodDebugInfo> method_infos(oat_writer.GetMethodDebugInfo());
-    elf_writer->WriteDebugInfo(method_infos);
-
-    ArrayRef<const uintptr_t> patch_locations(oat_writer.GetAbsolutePatchLocations());
-    elf_writer->WritePatchLocations(patch_locations);
+    elf_writer->WriteDebugInfo(oat_writer.GetMethodDebugInfo());
+    elf_writer->WritePatchLocations(oat_writer.GetAbsolutePatchLocations());
 
     return elf_writer->End();
   }
@@ -269,14 +264,9 @@
     std::unique_ptr<const InstructionSetFeatures> insn_features(
         InstructionSetFeatures::FromVariant(insn_set, "default", &error_msg));
     ASSERT_TRUE(insn_features.get() != nullptr) << error_msg;
-    std::vector<const DexFile*> dex_files;
-    uint32_t image_file_location_oat_checksum = 0;
-    uint32_t image_file_location_oat_begin = 0;
     std::unique_ptr<OatHeader> oat_header(OatHeader::Create(insn_set,
                                                             insn_features.get(),
-                                                            &dex_files,
-                                                            image_file_location_oat_checksum,
-                                                            image_file_location_oat_begin,
+                                                            0u,
                                                             nullptr));
     ASSERT_NE(oat_header.get(), nullptr);
     ASSERT_TRUE(oat_header->IsValid());
diff --git a/compiler/oat_writer.cc b/compiler/oat_writer.cc
index e8e775f..2b2f0e8 100644
--- a/compiler/oat_writer.cc
+++ b/compiler/oat_writer.cc
@@ -52,6 +52,97 @@
 
 namespace art {
 
+class OatWriter::OatClass {
+ public:
+  OatClass(size_t offset,
+           const dchecked_vector<CompiledMethod*>& compiled_methods,
+           uint32_t num_non_null_compiled_methods,
+           mirror::Class::Status status);
+  OatClass(OatClass&& src) = default;
+  size_t GetOatMethodOffsetsOffsetFromOatHeader(size_t class_def_method_index_) const;
+  size_t GetOatMethodOffsetsOffsetFromOatClass(size_t class_def_method_index_) const;
+  size_t SizeOf() const;
+  bool Write(OatWriter* oat_writer, OutputStream* out, const size_t file_offset) const;
+
+  CompiledMethod* GetCompiledMethod(size_t class_def_method_index) const {
+    return compiled_methods_[class_def_method_index];
+  }
+
+  // Offset of start of OatClass from beginning of OatHeader. It is
+  // used to validate file position when writing.
+  size_t offset_;
+
+  // CompiledMethods for each class_def_method_index, or null if no method is available.
+  dchecked_vector<CompiledMethod*> compiled_methods_;
+
+  // Offset from OatClass::offset_ to the OatMethodOffsets for the
+  // class_def_method_index. If 0, it means the corresponding
+  // CompiledMethod entry in OatClass::compiled_methods_ should be
+  // null and that the OatClass::type_ should be kOatClassBitmap.
+  dchecked_vector<uint32_t> oat_method_offsets_offsets_from_oat_class_;
+
+  // Data to write.
+
+  static_assert(mirror::Class::Status::kStatusMax < (1 << 16), "class status won't fit in 16bits");
+  int16_t status_;
+
+  static_assert(OatClassType::kOatClassMax < (1 << 16), "oat_class type won't fit in 16bits");
+  uint16_t type_;
+
+  uint32_t method_bitmap_size_;
+
+  // bit vector indexed by ClassDef method index. When
+  // OatClassType::type_ is kOatClassBitmap, a set bit indicates the
+  // method has an OatMethodOffsets in methods_offsets_, otherwise
+  // the entry was ommited to save space. If OatClassType::type_ is
+  // not is kOatClassBitmap, the bitmap will be null.
+  std::unique_ptr<BitVector> method_bitmap_;
+
+  // OatMethodOffsets and OatMethodHeaders for each CompiledMethod
+  // present in the OatClass. Note that some may be missing if
+  // OatClass::compiled_methods_ contains null values (and
+  // oat_method_offsets_offsets_from_oat_class_ should contain 0
+  // values in this case).
+  dchecked_vector<OatMethodOffsets> method_offsets_;
+  dchecked_vector<OatQuickMethodHeader> method_headers_;
+
+ private:
+  size_t GetMethodOffsetsRawSize() const {
+    return method_offsets_.size() * sizeof(method_offsets_[0]);
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(OatClass);
+};
+
+class OatWriter::OatDexFile {
+ public:
+  OatDexFile(size_t offset, const DexFile& dex_file);
+  OatDexFile(OatDexFile&& src) = default;
+
+  size_t SizeOf() const;
+  bool Write(OatWriter* oat_writer, OutputStream* out, const size_t file_offset) const;
+
+  // Offset of start of OatDexFile from beginning of OatHeader. It is
+  // used to validate file position when writing.
+  size_t offset_;
+
+  // Data to write.
+  uint32_t dex_file_location_size_;
+  const uint8_t* dex_file_location_data_;
+  uint32_t dex_file_location_checksum_;
+  uint32_t dex_file_offset_;
+  uint32_t lookup_table_offset_;
+  TypeLookupTable* lookup_table_;  // Owned by the dex file.
+  dchecked_vector<uint32_t> class_offsets_;
+
+ private:
+  size_t GetClassOffsetsRawSize() const {
+    return class_offsets_.size() * sizeof(class_offsets_[0]);
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(OatDexFile);
+};
+
 #define DCHECK_OFFSET() \
   DCHECK_EQ(static_cast<off_t>(file_offset + relative_offset), out->Seek(0, kSeekCurrent)) \
     << "file_offset=" << file_offset << " relative_offset=" << relative_offset
@@ -106,14 +197,14 @@
     size_oat_dex_file_location_data_(0),
     size_oat_dex_file_location_checksum_(0),
     size_oat_dex_file_offset_(0),
-    size_oat_dex_file_methods_offsets_(0),
+    size_oat_dex_file_lookup_table_offset_(0),
+    size_oat_dex_file_class_offsets_(0),
+    size_oat_lookup_table_alignment_(0),
+    size_oat_lookup_table_(0),
     size_oat_class_type_(0),
     size_oat_class_status_(0),
     size_oat_class_method_bitmaps_(0),
     size_oat_class_method_offsets_(0),
-    size_oat_lookup_table_alignment_(0),
-    size_oat_lookup_table_offset_(0),
-    size_oat_lookup_table_(0),
     method_offset_map_() {
   CHECK(key_value_store != nullptr);
   if (compiling_boot_image) {
@@ -180,9 +271,6 @@
 }
 
 OatWriter::~OatWriter() {
-  delete oat_header_;
-  STLDeleteElements(&oat_dex_files_);
-  STLDeleteElements(&oat_classes_);
 }
 
 struct OatWriter::GcMapDataAccess {
@@ -326,6 +414,11 @@
     : DexMethodVisitor(writer, offset),
       compiled_methods_(),
       num_non_null_compiled_methods_(0u) {
+    size_t num_classes = 0u;
+    for (const OatDexFile& oat_dex_file : writer_->oat_dex_files_) {
+      num_classes += oat_dex_file.class_offsets_.size();
+    }
+    writer_->oat_classes_.reserve(num_classes);
     compiled_methods_.reserve(256u);
   }
 
@@ -364,16 +457,16 @@
       status = mirror::Class::kStatusNotReady;
     }
 
-    OatClass* oat_class = new OatClass(offset_, compiled_methods_,
-                                       num_non_null_compiled_methods_, status);
-    writer_->oat_classes_.push_back(oat_class);
-    oat_class->UpdateChecksum(writer_->oat_header_);
-    offset_ += oat_class->SizeOf();
+    writer_->oat_classes_.emplace_back(offset_,
+                                       compiled_methods_,
+                                       num_non_null_compiled_methods_,
+                                       status);
+    offset_ += writer_->oat_classes_.back().SizeOf();
     return DexMethodVisitor::EndClass();
   }
 
  private:
-  std::vector<CompiledMethod*> compiled_methods_;
+  dchecked_vector<CompiledMethod*> compiled_methods_;
   size_t num_non_null_compiled_methods_;
 };
 
@@ -396,7 +489,7 @@
 
   bool VisitMethod(size_t class_def_method_index, const ClassDataItemIterator& it)
       SHARED_REQUIRES(Locks::mutator_lock_) {
-    OatClass* oat_class = writer_->oat_classes_[oat_class_index_];
+    OatClass* oat_class = &writer_->oat_classes_[oat_class_index_];
     CompiledMethod* compiled_method = oat_class->GetCompiledMethod(class_def_method_index);
 
     if (compiled_method != nullptr) {
@@ -583,7 +676,7 @@
 
   bool VisitMethod(size_t class_def_method_index, const ClassDataItemIterator& it ATTRIBUTE_UNUSED)
       SHARED_REQUIRES(Locks::mutator_lock_) {
-    OatClass* oat_class = writer_->oat_classes_[oat_class_index_];
+    OatClass* oat_class = &writer_->oat_classes_[oat_class_index_];
     CompiledMethod* compiled_method = oat_class->GetCompiledMethod(class_def_method_index);
 
     if (compiled_method != nullptr) {
@@ -600,7 +693,6 @@
           DataAccess::SetOffset(oat_class, method_offsets_index_, offset_);
           dedupe_map_.PutBefore(lb, map.data(), offset_);
           offset_ += map_size;
-          writer_->oat_header_->UpdateChecksum(&map[0], map_size);
         }
       }
       ++method_offsets_index_;
@@ -624,7 +716,7 @@
 
   bool VisitMethod(size_t class_def_method_index, const ClassDataItemIterator& it)
       SHARED_REQUIRES(Locks::mutator_lock_) {
-    OatClass* oat_class = writer_->oat_classes_[oat_class_index_];
+    OatClass* oat_class = &writer_->oat_classes_[oat_class_index_];
     CompiledMethod* compiled_method = oat_class->GetCompiledMethod(class_def_method_index);
 
     OatMethodOffsets offsets(0u);
@@ -715,7 +807,7 @@
 
   bool VisitMethod(size_t class_def_method_index, const ClassDataItemIterator& it)
       SHARED_REQUIRES(Locks::mutator_lock_) {
-    OatClass* oat_class = writer_->oat_classes_[oat_class_index_];
+    OatClass* oat_class = &writer_->oat_classes_[oat_class_index_];
     const CompiledMethod* compiled_method = oat_class->GetCompiledMethod(class_def_method_index);
 
     // No thread suspension since dex_cache_ that may get invalidated if that occurs.
@@ -752,8 +844,7 @@
             << PrettyMethod(it.GetMemberIndex(), *dex_file_);
         const OatQuickMethodHeader& method_header =
             oat_class->method_headers_[method_offsets_index_];
-        writer_->oat_header_->UpdateChecksum(&method_header, sizeof(method_header));
-        if (!out->WriteFully(&method_header, sizeof(method_header))) {
+        if (!writer_->WriteData(out, &method_header, sizeof(method_header))) {
           ReportWriteFailure("method header", it);
           return false;
         }
@@ -790,8 +881,7 @@
           }
         }
 
-        writer_->oat_header_->UpdateChecksum(quick_code.data(), code_size);
-        if (!out->WriteFully(quick_code.data(), code_size)) {
+        if (!writer_->WriteData(out, quick_code.data(), code_size)) {
           ReportWriteFailure("method code", it);
           return false;
         }
@@ -945,7 +1035,7 @@
   }
 
   bool VisitMethod(size_t class_def_method_index, const ClassDataItemIterator& it) {
-    OatClass* oat_class = writer_->oat_classes_[oat_class_index_];
+    OatClass* oat_class = &writer_->oat_classes_[oat_class_index_];
     const CompiledMethod* compiled_method = oat_class->GetCompiledMethod(class_def_method_index);
 
     if (compiled_method != nullptr) {  // ie. not an abstract method
@@ -963,7 +1053,7 @@
           << map_size << " " << map_offset << " " << offset_ << " "
           << PrettyMethod(it.GetMemberIndex(), *dex_file_) << " for " << DataAccess::Name();
       if (map_size != 0u && map_offset == offset_) {
-        if (UNLIKELY(!out->WriteFully(&map[0], map_size))) {
+        if (UNLIKELY(!writer_->WriteData(out, map.data(), map_size))) {
           ReportWriteFailure(it);
           return false;
         }
@@ -1028,12 +1118,12 @@
 }
 
 size_t OatWriter::InitOatHeader() {
-  oat_header_ = OatHeader::Create(compiler_driver_->GetInstructionSet(),
-                                  compiler_driver_->GetInstructionSetFeatures(),
-                                  dex_files_,
-                                  image_file_location_oat_checksum_,
-                                  image_file_location_oat_begin_,
-                                  key_value_store_);
+  oat_header_.reset(OatHeader::Create(compiler_driver_->GetInstructionSet(),
+                                      compiler_driver_->GetInstructionSetFeatures(),
+                                      dchecked_integral_cast<uint32_t>(dex_files_->size()),
+                                      key_value_store_));
+  oat_header_->SetImageFileLocationOatChecksum(image_file_location_oat_checksum_);
+  oat_header_->SetImageFileLocationOatDataBegin(image_file_location_oat_begin_);
 
   return oat_header_->GetHeaderSize();
 }
@@ -1043,9 +1133,8 @@
   for (size_t i = 0; i != dex_files_->size(); ++i) {
     const DexFile* dex_file = (*dex_files_)[i];
     CHECK(dex_file != nullptr);
-    OatDexFile* oat_dex_file = new OatDexFile(offset, *dex_file);
-    oat_dex_files_.push_back(oat_dex_file);
-    offset += oat_dex_file->SizeOf();
+    oat_dex_files_.emplace_back(offset, *dex_file);
+    offset += oat_dex_files_.back().SizeOf();
   }
   return offset;
 }
@@ -1059,12 +1148,12 @@
     size_dex_file_alignment_ += offset - original_offset;
 
     // set offset in OatDexFile to DexFile
-    oat_dex_files_[i]->dex_file_offset_ = offset;
+    oat_dex_files_[i].dex_file_offset_ = offset;
 
     const DexFile* dex_file = (*dex_files_)[i];
 
     // Initialize type lookup table
-    oat_dex_files_[i]->lookup_table_ = dex_file->GetTypeLookupTable();
+    oat_dex_files_[i].lookup_table_ = dex_file->GetTypeLookupTable();
 
     offset += dex_file->GetHeader().file_size_;
   }
@@ -1072,14 +1161,14 @@
 }
 
 size_t OatWriter::InitLookupTables(size_t offset) {
-  for (OatDexFile* oat_dex_file : oat_dex_files_) {
-    if (oat_dex_file->lookup_table_ != nullptr) {
+  for (OatDexFile& oat_dex_file : oat_dex_files_) {
+    if (oat_dex_file.lookup_table_ != nullptr) {
       uint32_t aligned_offset = RoundUp(offset, 4);
-      oat_dex_file->lookup_table_offset_ = aligned_offset;
+      oat_dex_file.lookup_table_offset_ = aligned_offset;
       size_oat_lookup_table_alignment_ += aligned_offset - offset;
-      offset = aligned_offset + oat_dex_file->lookup_table_->RawDataLength();
+      offset = aligned_offset + oat_dex_file.lookup_table_->RawDataLength();
     } else {
-      oat_dex_file->lookup_table_offset_ = 0;
+      oat_dex_file.lookup_table_offset_ = 0;
     }
   }
   return offset;
@@ -1094,13 +1183,12 @@
 
   // Update oat_dex_files_.
   auto oat_class_it = oat_classes_.begin();
-  for (OatDexFile* oat_dex_file : oat_dex_files_) {
-    for (uint32_t& method_offset : oat_dex_file->methods_offsets_) {
+  for (OatDexFile& oat_dex_file : oat_dex_files_) {
+    for (uint32_t& class_offset : oat_dex_file.class_offsets_) {
       DCHECK(oat_class_it != oat_classes_.end());
-      method_offset = (*oat_class_it)->offset_;
+      class_offset = oat_class_it->offset_;
       ++oat_class_it;
     }
-    oat_dex_file->UpdateChecksum(oat_header_);
   }
   CHECK(oat_class_it == oat_classes_.end());
 
@@ -1184,17 +1272,14 @@
 }
 
 bool OatWriter::WriteRodata(OutputStream* out) {
-  const off_t raw_file_offset = out->Seek(0, kSeekCurrent);
-  if (raw_file_offset == (off_t) -1) {
-    LOG(ERROR) << "Failed to get file offset in " << out->GetLocation();
+  if (!GetOatDataOffset(out)) {
     return false;
   }
-  const size_t file_offset = static_cast<size_t>(raw_file_offset);
-  oat_data_offset_ = file_offset;
+  const size_t file_offset = oat_data_offset_;
 
   // Reserve space for header. It will be written last - after updating the checksum.
   size_t header_size = oat_header_->GetHeaderSize();
-  if (out->Seek(header_size, kSeekCurrent) == (off_t) -1) {
+  if (out->Seek(header_size, kSeekCurrent) == static_cast<off_t>(-1)) {
     PLOG(ERROR) << "Failed to reserve space for oat header in " << out->GetLocation();
     return false;
   }
@@ -1207,7 +1292,7 @@
   }
 
   off_t tables_end_offset = out->Seek(0, kSeekCurrent);
-  if (tables_end_offset == (off_t) -1) {
+  if (tables_end_offset == static_cast<off_t>(-1)) {
     LOG(ERROR) << "Failed to seek to oat code position in " << out->GetLocation();
     return false;
   }
@@ -1252,7 +1337,7 @@
   }
 
   const off_t oat_end_file_offset = out->Seek(0, kSeekCurrent);
-  if (oat_end_file_offset == (off_t) -1) {
+  if (oat_end_file_offset == static_cast<off_t>(-1)) {
     LOG(ERROR) << "Failed to get oat end file offset in " << out->GetLocation();
     return false;
   }
@@ -1288,14 +1373,14 @@
     DO_STAT(size_oat_dex_file_location_data_);
     DO_STAT(size_oat_dex_file_location_checksum_);
     DO_STAT(size_oat_dex_file_offset_);
-    DO_STAT(size_oat_dex_file_methods_offsets_);
+    DO_STAT(size_oat_dex_file_lookup_table_offset_);
+    DO_STAT(size_oat_dex_file_class_offsets_);
+    DO_STAT(size_oat_lookup_table_alignment_);
+    DO_STAT(size_oat_lookup_table_);
     DO_STAT(size_oat_class_type_);
     DO_STAT(size_oat_class_status_);
     DO_STAT(size_oat_class_method_bitmaps_);
     DO_STAT(size_oat_class_method_offsets_);
-    DO_STAT(size_oat_lookup_table_alignment_);
-    DO_STAT(size_oat_lookup_table_offset_);
-    DO_STAT(size_oat_lookup_table_);
     #undef DO_STAT
 
     VLOG(compiler) << "size_total=" << PrettySize(size_total) << " (" << size_total << "B)"; \
@@ -1306,17 +1391,20 @@
   CHECK_EQ(file_offset + size_, static_cast<size_t>(oat_end_file_offset));
   CHECK_EQ(size_, relative_offset);
 
+  // Finalize the header checksum.
+  oat_header_->UpdateChecksumWithHeaderData();
+
   // Write the header now that the checksum is final.
-  if (out->Seek(file_offset, kSeekSet) == (off_t) -1) {
+  if (out->Seek(file_offset, kSeekSet) == static_cast<off_t>(-1)) {
     PLOG(ERROR) << "Failed to seek to oat header position in " << out->GetLocation();
     return false;
   }
   DCHECK_EQ(file_offset, static_cast<size_t>(out->Seek(0, kSeekCurrent)));
-  if (!out->WriteFully(oat_header_, header_size)) {
+  if (!out->WriteFully(oat_header_.get(), header_size)) {
     PLOG(ERROR) << "Failed to write oat header to " << out->GetLocation();
     return false;
   }
-  if (out->Seek(oat_end_file_offset, kSeekSet) == (off_t) -1) {
+  if (out->Seek(oat_end_file_offset, kSeekSet) == static_cast<off_t>(-1)) {
     PLOG(ERROR) << "Failed to seek to end after writing oat header to " << out->GetLocation();
     return false;
   }
@@ -1327,13 +1415,13 @@
 
 bool OatWriter::WriteTables(OutputStream* out, const size_t file_offset) {
   for (size_t i = 0; i != oat_dex_files_.size(); ++i) {
-    if (!oat_dex_files_[i]->Write(this, out, file_offset)) {
+    if (!oat_dex_files_[i].Write(this, out, file_offset)) {
       PLOG(ERROR) << "Failed to write oat dex information to " << out->GetLocation();
       return false;
     }
   }
   for (size_t i = 0; i != oat_dex_files_.size(); ++i) {
-    uint32_t expected_offset = file_offset + oat_dex_files_[i]->dex_file_offset_;
+    uint32_t expected_offset = file_offset + oat_dex_files_[i].dex_file_offset_;
     off_t actual_offset = out->Seek(expected_offset, kSeekSet);
     if (static_cast<uint32_t>(actual_offset) != expected_offset) {
       const DexFile* dex_file = (*dex_files_)[i];
@@ -1353,7 +1441,7 @@
     return false;
   }
   for (size_t i = 0; i != oat_classes_.size(); ++i) {
-    if (!oat_classes_[i]->Write(this, out, file_offset)) {
+    if (!oat_classes_[i].Write(this, out, file_offset)) {
       PLOG(ERROR) << "Failed to write oat methods information to " << out->GetLocation();
       return false;
     }
@@ -1363,8 +1451,8 @@
 
 bool OatWriter::WriteLookupTables(OutputStream* out, const size_t file_offset) {
   for (size_t i = 0; i < oat_dex_files_.size(); ++i) {
-    const uint32_t lookup_table_offset = oat_dex_files_[i]->lookup_table_offset_;
-    const TypeLookupTable* table = oat_dex_files_[i]->lookup_table_;
+    const uint32_t lookup_table_offset = oat_dex_files_[i].lookup_table_offset_;
+    const TypeLookupTable* table = oat_dex_files_[i].lookup_table_;
     DCHECK_EQ(lookup_table_offset == 0, table == nullptr);
     if (lookup_table_offset == 0) {
       continue;
@@ -1378,7 +1466,7 @@
       return false;
     }
     if (table != nullptr) {
-      if (!out->WriteFully(table->RawData(), table->RawDataLength())) {
+      if (!WriteData(out, table->RawData(), table->RawDataLength())) {
         const DexFile* dex_file = (*dex_files_)[i];
         PLOG(ERROR) << "Failed to write lookup table for " << dex_file->GetLocation()
                     << " to " << out->GetLocation();
@@ -1427,7 +1515,7 @@
         uint32_t alignment_padding = aligned_offset - relative_offset; \
         out->Seek(alignment_padding, kSeekCurrent); \
         size_trampoline_alignment_ += alignment_padding; \
-        if (!out->WriteFully(&(*field)[0], field->size())) { \
+        if (!WriteData(out, field->data(), field->size())) { \
           PLOG(ERROR) << "Failed to write " # field " to " << out->GetLocation(); \
           return false; \
         } \
@@ -1469,6 +1557,17 @@
   return relative_offset;
 }
 
+bool OatWriter::GetOatDataOffset(OutputStream* out) {
+  // Get the elf file offset of the oat file.
+  const off_t raw_file_offset = out->Seek(0, kSeekCurrent);
+  if (raw_file_offset == static_cast<off_t>(-1)) {
+    LOG(ERROR) << "Failed to get file offset in " << out->GetLocation();
+    return false;
+  }
+  oat_data_offset_ = static_cast<size_t>(raw_file_offset);
+  return true;
+}
+
 bool OatWriter::WriteCodeAlignment(OutputStream* out, uint32_t aligned_code_delta) {
   static const uint8_t kPadding[] = {
       0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u
@@ -1481,6 +1580,11 @@
   return true;
 }
 
+bool OatWriter::WriteData(OutputStream* out, const void* data, size_t size) {
+  oat_header_->UpdateChecksum(data, size);
+  return out->WriteFully(data, size);
+}
+
 std::pair<bool, uint32_t> OatWriter::MethodOffsetMap::FindMethodOffset(MethodReference ref) {
   auto it = map.find(ref);
   if (it == map.end()) {
@@ -1498,7 +1602,7 @@
   dex_file_location_checksum_ = dex_file.GetLocationChecksum();
   dex_file_offset_ = 0;
   lookup_table_offset_ = 0;
-  methods_offsets_.resize(dex_file.NumClassDefs());
+  class_offsets_.resize(dex_file.NumClassDefs());
 }
 
 size_t OatWriter::OatDexFile::SizeOf() const {
@@ -1507,63 +1611,50 @@
           + sizeof(dex_file_location_checksum_)
           + sizeof(dex_file_offset_)
           + sizeof(lookup_table_offset_)
-          + (sizeof(methods_offsets_[0]) * methods_offsets_.size());
-}
-
-void OatWriter::OatDexFile::UpdateChecksum(OatHeader* oat_header) const {
-  oat_header->UpdateChecksum(&dex_file_location_size_, sizeof(dex_file_location_size_));
-  oat_header->UpdateChecksum(dex_file_location_data_, dex_file_location_size_);
-  oat_header->UpdateChecksum(&dex_file_location_checksum_, sizeof(dex_file_location_checksum_));
-  oat_header->UpdateChecksum(&dex_file_offset_, sizeof(dex_file_offset_));
-  oat_header->UpdateChecksum(&lookup_table_offset_, sizeof(lookup_table_offset_));
-  if (lookup_table_ != nullptr) {
-    oat_header->UpdateChecksum(lookup_table_->RawData(), lookup_table_->RawDataLength());
-  }
-  oat_header->UpdateChecksum(&methods_offsets_[0],
-                            sizeof(methods_offsets_[0]) * methods_offsets_.size());
+          + (sizeof(class_offsets_[0]) * class_offsets_.size());
 }
 
 bool OatWriter::OatDexFile::Write(OatWriter* oat_writer,
                                   OutputStream* out,
                                   const size_t file_offset) const {
   DCHECK_OFFSET_();
-  if (!out->WriteFully(&dex_file_location_size_, sizeof(dex_file_location_size_))) {
+  if (!oat_writer->WriteData(out, &dex_file_location_size_, sizeof(dex_file_location_size_))) {
     PLOG(ERROR) << "Failed to write dex file location length to " << out->GetLocation();
     return false;
   }
   oat_writer->size_oat_dex_file_location_size_ += sizeof(dex_file_location_size_);
-  if (!out->WriteFully(dex_file_location_data_, dex_file_location_size_)) {
+  if (!oat_writer->WriteData(out, dex_file_location_data_, dex_file_location_size_)) {
     PLOG(ERROR) << "Failed to write dex file location data to " << out->GetLocation();
     return false;
   }
   oat_writer->size_oat_dex_file_location_data_ += dex_file_location_size_;
-  if (!out->WriteFully(&dex_file_location_checksum_, sizeof(dex_file_location_checksum_))) {
+  if (!oat_writer->WriteData(out,
+                             &dex_file_location_checksum_,
+                             sizeof(dex_file_location_checksum_))) {
     PLOG(ERROR) << "Failed to write dex file location checksum to " << out->GetLocation();
     return false;
   }
   oat_writer->size_oat_dex_file_location_checksum_ += sizeof(dex_file_location_checksum_);
-  if (!out->WriteFully(&dex_file_offset_, sizeof(dex_file_offset_))) {
+  if (!oat_writer->WriteData(out, &dex_file_offset_, sizeof(dex_file_offset_))) {
     PLOG(ERROR) << "Failed to write dex file offset to " << out->GetLocation();
     return false;
   }
   oat_writer->size_oat_dex_file_offset_ += sizeof(dex_file_offset_);
-  if (!out->WriteFully(&lookup_table_offset_, sizeof(lookup_table_offset_))) {
+  if (!oat_writer->WriteData(out, &lookup_table_offset_, sizeof(lookup_table_offset_))) {
     PLOG(ERROR) << "Failed to write lookup table offset to " << out->GetLocation();
     return false;
   }
-  oat_writer->size_oat_lookup_table_offset_ += sizeof(lookup_table_offset_);
-  if (!out->WriteFully(&methods_offsets_[0],
-                      sizeof(methods_offsets_[0]) * methods_offsets_.size())) {
+  oat_writer->size_oat_dex_file_lookup_table_offset_ += sizeof(lookup_table_offset_);
+  if (!oat_writer->WriteData(out, class_offsets_.data(), GetClassOffsetsRawSize())) {
     PLOG(ERROR) << "Failed to write methods offsets to " << out->GetLocation();
     return false;
   }
-  oat_writer->size_oat_dex_file_methods_offsets_ +=
-      sizeof(methods_offsets_[0]) * methods_offsets_.size();
+  oat_writer->size_oat_dex_file_class_offsets_ += GetClassOffsetsRawSize();
   return true;
 }
 
 OatWriter::OatClass::OatClass(size_t offset,
-                              const std::vector<CompiledMethod*>& compiled_methods,
+                              const dchecked_vector<CompiledMethod*>& compiled_methods,
                               uint32_t num_non_null_compiled_methods,
                               mirror::Class::Status status)
     : compiled_methods_(compiled_methods) {
@@ -1593,7 +1684,7 @@
 
   uint32_t oat_method_offsets_offset_from_oat_class = sizeof(type_) + sizeof(status_);
   if (type_ == kOatClassSomeCompiled) {
-    method_bitmap_ = new BitVector(num_methods, false, Allocator::GetMallocAllocator());
+    method_bitmap_.reset(new BitVector(num_methods, false, Allocator::GetMallocAllocator()));
     method_bitmap_size_ = method_bitmap_->GetSizeOf();
     oat_method_offsets_offset_from_oat_class += sizeof(method_bitmap_size_);
     oat_method_offsets_offset_from_oat_class += method_bitmap_size_;
@@ -1616,10 +1707,6 @@
   }
 }
 
-OatWriter::OatClass::~OatClass() {
-  delete method_bitmap_;
-}
-
 size_t OatWriter::OatClass::GetOatMethodOffsetsOffsetFromOatHeader(
     size_t class_def_method_index_) const {
   uint32_t method_offset = GetOatMethodOffsetsOffsetFromOatClass(class_def_method_index_);
@@ -1642,51 +1729,42 @@
           + (sizeof(method_offsets_[0]) * method_offsets_.size());
 }
 
-void OatWriter::OatClass::UpdateChecksum(OatHeader* oat_header) const {
-  oat_header->UpdateChecksum(&status_, sizeof(status_));
-  oat_header->UpdateChecksum(&type_, sizeof(type_));
-  if (method_bitmap_size_ != 0) {
-    CHECK_EQ(kOatClassSomeCompiled, type_);
-    oat_header->UpdateChecksum(&method_bitmap_size_, sizeof(method_bitmap_size_));
-    oat_header->UpdateChecksum(method_bitmap_->GetRawStorage(), method_bitmap_size_);
-  }
-  oat_header->UpdateChecksum(&method_offsets_[0],
-                             sizeof(method_offsets_[0]) * method_offsets_.size());
-}
-
 bool OatWriter::OatClass::Write(OatWriter* oat_writer,
                                 OutputStream* out,
                                 const size_t file_offset) const {
   DCHECK_OFFSET_();
-  if (!out->WriteFully(&status_, sizeof(status_))) {
+  if (!oat_writer->WriteData(out, &status_, sizeof(status_))) {
     PLOG(ERROR) << "Failed to write class status to " << out->GetLocation();
     return false;
   }
   oat_writer->size_oat_class_status_ += sizeof(status_);
-  if (!out->WriteFully(&type_, sizeof(type_))) {
+
+  if (!oat_writer->WriteData(out, &type_, sizeof(type_))) {
     PLOG(ERROR) << "Failed to write oat class type to " << out->GetLocation();
     return false;
   }
   oat_writer->size_oat_class_type_ += sizeof(type_);
+
   if (method_bitmap_size_ != 0) {
     CHECK_EQ(kOatClassSomeCompiled, type_);
-    if (!out->WriteFully(&method_bitmap_size_, sizeof(method_bitmap_size_))) {
+    if (!oat_writer->WriteData(out, &method_bitmap_size_, sizeof(method_bitmap_size_))) {
       PLOG(ERROR) << "Failed to write method bitmap size to " << out->GetLocation();
       return false;
     }
     oat_writer->size_oat_class_method_bitmaps_ += sizeof(method_bitmap_size_);
-    if (!out->WriteFully(method_bitmap_->GetRawStorage(), method_bitmap_size_)) {
+
+    if (!oat_writer->WriteData(out, method_bitmap_->GetRawStorage(), method_bitmap_size_)) {
       PLOG(ERROR) << "Failed to write method bitmap to " << out->GetLocation();
       return false;
     }
     oat_writer->size_oat_class_method_bitmaps_ += method_bitmap_size_;
   }
-  if (!out->WriteFully(&method_offsets_[0],
-                      sizeof(method_offsets_[0]) * method_offsets_.size())) {
+
+  if (!oat_writer->WriteData(out, method_offsets_.data(), GetMethodOffsetsRawSize())) {
     PLOG(ERROR) << "Failed to write method offsets to " << out->GetLocation();
     return false;
   }
-  oat_writer->size_oat_class_method_offsets_ += sizeof(method_offsets_[0]) * method_offsets_.size();
+  oat_writer->size_oat_class_method_offsets_ += GetMethodOffsetsRawSize();
   return true;
 }
 
diff --git a/compiler/oat_writer.h b/compiler/oat_writer.h
index 6c46ebc..5feb5fc 100644
--- a/compiler/oat_writer.h
+++ b/compiler/oat_writer.h
@@ -21,12 +21,14 @@
 #include <cstddef>
 #include <memory>
 
+#include "base/dchecked_vector.h"
 #include "linker/relative_patcher.h"  // For linker::RelativePatcherTargetProvider.
 #include "mem_map.h"
 #include "method_reference.h"
 #include "mirror/class.h"
 #include "oat.h"
 #include "safe_map.h"
+#include "utils/array_ref.h"
 
 namespace art {
 
@@ -124,8 +126,8 @@
     return bss_size_;
   }
 
-  const std::vector<uintptr_t>& GetAbsolutePatchLocations() const {
-    return absolute_patch_locations_;
+  ArrayRef<const uintptr_t> GetAbsolutePatchLocations() const {
+    return ArrayRef<const uintptr_t>(absolute_patch_locations_);
   }
 
   bool WriteRodata(OutputStream* out);
@@ -133,8 +135,8 @@
 
   ~OatWriter();
 
-  const std::vector<dwarf::MethodDebugInfo>& GetMethodDebugInfo() const {
-    return method_info_;
+  ArrayRef<const dwarf::MethodDebugInfo> GetMethodDebugInfo() const {
+    return ArrayRef<const dwarf::MethodDebugInfo>(method_info_);
   }
 
   const CompilerDriver* GetCompilerDriver() {
@@ -142,6 +144,9 @@
   }
 
  private:
+  class OatClass;
+  class OatDexFile;
+
   // The DataAccess classes are helper classes that provide access to members related to
   // a given map, i.e. GC map, mapping table or vmap table. By abstracting these away
   // we can share a lot of code for processing the maps with template classes below.
@@ -175,10 +180,8 @@
   size_t InitDexFiles(size_t offset);
   size_t InitOatClasses(size_t offset);
   size_t InitOatMaps(size_t offset);
-  size_t InitOatCode(size_t offset)
-      SHARED_REQUIRES(Locks::mutator_lock_);
-  size_t InitOatCodeDexFiles(size_t offset)
-      SHARED_REQUIRES(Locks::mutator_lock_);
+  size_t InitOatCode(size_t offset);
+  size_t InitOatCodeDexFiles(size_t offset);
 
   bool WriteTables(OutputStream* out, const size_t file_offset);
   bool WriteLookupTables(OutputStream* out, const size_t file_offset);
@@ -186,93 +189,11 @@
   size_t WriteCode(OutputStream* out, const size_t file_offset, size_t relative_offset);
   size_t WriteCodeDexFiles(OutputStream* out, const size_t file_offset, size_t relative_offset);
 
+  bool GetOatDataOffset(OutputStream* out);
   bool WriteCodeAlignment(OutputStream* out, uint32_t aligned_code_delta);
+  bool WriteData(OutputStream* out, const void* data, size_t size);
 
-  class OatDexFile {
-   public:
-    OatDexFile(size_t offset, const DexFile& dex_file);
-    size_t SizeOf() const;
-    void UpdateChecksum(OatHeader* oat_header) const;
-    bool Write(OatWriter* oat_writer, OutputStream* out, const size_t file_offset) const;
-
-    // Offset of start of OatDexFile from beginning of OatHeader. It is
-    // used to validate file position when writing.
-    size_t offset_;
-
-    // data to write
-    uint32_t dex_file_location_size_;
-    const uint8_t* dex_file_location_data_;
-    uint32_t dex_file_location_checksum_;
-    uint32_t dex_file_offset_;
-    uint32_t lookup_table_offset_;
-    TypeLookupTable* lookup_table_;  // Owned by the dex file.
-    std::vector<uint32_t> methods_offsets_;
-
-   private:
-    DISALLOW_COPY_AND_ASSIGN(OatDexFile);
-  };
-
-  class OatClass {
-   public:
-    OatClass(size_t offset,
-             const std::vector<CompiledMethod*>& compiled_methods,
-             uint32_t num_non_null_compiled_methods,
-             mirror::Class::Status status);
-    ~OatClass();
-    size_t GetOatMethodOffsetsOffsetFromOatHeader(size_t class_def_method_index_) const;
-    size_t GetOatMethodOffsetsOffsetFromOatClass(size_t class_def_method_index_) const;
-    size_t SizeOf() const;
-    void UpdateChecksum(OatHeader* oat_header) const;
-    bool Write(OatWriter* oat_writer, OutputStream* out, const size_t file_offset) const;
-
-    CompiledMethod* GetCompiledMethod(size_t class_def_method_index) const {
-      DCHECK_LT(class_def_method_index, compiled_methods_.size());
-      return compiled_methods_[class_def_method_index];
-    }
-
-    // Offset of start of OatClass from beginning of OatHeader. It is
-    // used to validate file position when writing.
-    size_t offset_;
-
-    // CompiledMethods for each class_def_method_index, or null if no method is available.
-    std::vector<CompiledMethod*> compiled_methods_;
-
-    // Offset from OatClass::offset_ to the OatMethodOffsets for the
-    // class_def_method_index. If 0, it means the corresponding
-    // CompiledMethod entry in OatClass::compiled_methods_ should be
-    // null and that the OatClass::type_ should be kOatClassBitmap.
-    std::vector<uint32_t> oat_method_offsets_offsets_from_oat_class_;
-
-    // data to write
-
-    static_assert(mirror::Class::Status::kStatusMax < (2 ^ 16), "class status won't fit in 16bits");
-    int16_t status_;
-
-    static_assert(OatClassType::kOatClassMax < (2 ^ 16), "oat_class type won't fit in 16bits");
-    uint16_t type_;
-
-    uint32_t method_bitmap_size_;
-
-    // bit vector indexed by ClassDef method index. When
-    // OatClassType::type_ is kOatClassBitmap, a set bit indicates the
-    // method has an OatMethodOffsets in methods_offsets_, otherwise
-    // the entry was ommited to save space. If OatClassType::type_ is
-    // not is kOatClassBitmap, the bitmap will be null.
-    BitVector* method_bitmap_;
-
-    // OatMethodOffsets and OatMethodHeaders for each CompiledMethod
-    // present in the OatClass. Note that some may be missing if
-    // OatClass::compiled_methods_ contains null values (and
-    // oat_method_offsets_offsets_from_oat_class_ should contain 0
-    // values in this case).
-    std::vector<OatMethodOffsets> method_offsets_;
-    std::vector<OatQuickMethodHeader> method_headers_;
-
-   private:
-    DISALLOW_COPY_AND_ASSIGN(OatClass);
-  };
-
-  std::vector<dwarf::MethodDebugInfo> method_info_;
+  dchecked_vector<dwarf::MethodDebugInfo> method_info_;
 
   const CompilerDriver* const compiler_driver_;
   ImageWriter* const image_writer_;
@@ -301,9 +222,9 @@
 
   // data to write
   SafeMap<std::string, std::string>* key_value_store_;
-  OatHeader* oat_header_;
-  std::vector<OatDexFile*> oat_dex_files_;
-  std::vector<OatClass*> oat_classes_;
+  std::unique_ptr<OatHeader> oat_header_;
+  dchecked_vector<OatDexFile> oat_dex_files_;
+  dchecked_vector<OatClass> oat_classes_;
   std::unique_ptr<const std::vector<uint8_t>> jni_dlsym_lookup_;
   std::unique_ptr<const std::vector<uint8_t>> quick_generic_jni_trampoline_;
   std::unique_ptr<const std::vector<uint8_t>> quick_imt_conflict_trampoline_;
@@ -336,14 +257,14 @@
   uint32_t size_oat_dex_file_location_data_;
   uint32_t size_oat_dex_file_location_checksum_;
   uint32_t size_oat_dex_file_offset_;
-  uint32_t size_oat_dex_file_methods_offsets_;
+  uint32_t size_oat_dex_file_lookup_table_offset_;
+  uint32_t size_oat_dex_file_class_offsets_;
+  uint32_t size_oat_lookup_table_alignment_;
+  uint32_t size_oat_lookup_table_;
   uint32_t size_oat_class_type_;
   uint32_t size_oat_class_status_;
   uint32_t size_oat_class_method_bitmaps_;
   uint32_t size_oat_class_method_offsets_;
-  uint32_t size_oat_lookup_table_alignment_;
-  uint32_t size_oat_lookup_table_offset_;
-  uint32_t size_oat_lookup_table_;
 
   std::unique_ptr<linker::RelativePatcher> relative_patcher_;
 
diff --git a/compiler/trampolines/trampoline_compiler.h b/compiler/trampolines/trampoline_compiler.h
index 9fb2245..66d5ac3 100644
--- a/compiler/trampolines/trampoline_compiler.h
+++ b/compiler/trampolines/trampoline_compiler.h
@@ -25,12 +25,12 @@
 namespace art {
 
 // Create code that will invoke the function held in thread local storage.
-const std::vector<uint8_t>* CreateTrampoline32(InstructionSet isa, EntryPointCallingConvention abi,
-                                               ThreadOffset<4> entry_point_offset)
-    SHARED_REQUIRES(Locks::mutator_lock_);
-const std::vector<uint8_t>* CreateTrampoline64(InstructionSet isa, EntryPointCallingConvention abi,
-                                               ThreadOffset<8> entry_point_offset)
-    SHARED_REQUIRES(Locks::mutator_lock_);
+const std::vector<uint8_t>* CreateTrampoline32(InstructionSet isa,
+                                               EntryPointCallingConvention abi,
+                                               ThreadOffset<4> entry_point_offset);
+const std::vector<uint8_t>* CreateTrampoline64(InstructionSet isa,
+                                               EntryPointCallingConvention abi,
+                                               ThreadOffset<8> entry_point_offset);
 
 }  // namespace art
 
diff --git a/dex2oat/dex2oat.cc b/dex2oat/dex2oat.cc
index 2aa4085..d19d80b 100644
--- a/dex2oat/dex2oat.cc
+++ b/dex2oat/dex2oat.cc
@@ -71,6 +71,7 @@
 #include "oat_writer.h"
 #include "os.h"
 #include "runtime.h"
+#include "runtime_options.h"
 #include "ScopedLocalRef.h"
 #include "scoped_thread_state_change.h"
 #include "utils.h"
@@ -667,15 +668,14 @@
       parser_options->boot_image_filename += "/framework/boot.art";
     }
     if (!parser_options->boot_image_filename.empty()) {
-      boot_image_option_ += "-Ximage:";
-      boot_image_option_ += parser_options->boot_image_filename;
+      boot_image_filename_ = parser_options->boot_image_filename;
     }
 
     if (image_classes_filename_ != nullptr && !IsBootImage()) {
       Usage("--image-classes should only be used with --image");
     }
 
-    if (image_classes_filename_ != nullptr && !boot_image_option_.empty()) {
+    if (image_classes_filename_ != nullptr && !boot_image_filename_.empty()) {
       Usage("--image-classes should not be used with --boot-image");
     }
 
@@ -687,7 +687,7 @@
       Usage("--compiled-classes should only be used with --image");
     }
 
-    if (compiled_classes_filename_ != nullptr && !boot_image_option_.empty()) {
+    if (compiled_classes_filename_ != nullptr && !boot_image_filename_.empty()) {
       Usage("--compiled-classes should not be used with --boot-image");
     }
 
@@ -719,7 +719,7 @@
       Usage("--zip-location should be supplied with --zip-fd");
     }
 
-    if (boot_image_option_.empty()) {
+    if (boot_image_filename_.empty()) {
       if (image_base_ == 0) {
         Usage("Non-zero --base not specified");
       }
@@ -1014,20 +1014,10 @@
   // boot class path.
   bool Setup() {
     TimingLogger::ScopedTiming t("dex2oat Setup", timings_);
-    RuntimeOptions runtime_options;
     art::MemMap::Init();  // For ZipEntry::ExtractToMemMap.
-    if (boot_image_option_.empty()) {
-      std::string boot_class_path = "-Xbootclasspath:";
-      boot_class_path += Join(dex_filenames_, ':');
-      runtime_options.push_back(std::make_pair(boot_class_path, nullptr));
-      std::string boot_class_path_locations = "-Xbootclasspath-locations:";
-      boot_class_path_locations += Join(dex_locations_, ':');
-      runtime_options.push_back(std::make_pair(boot_class_path_locations, nullptr));
-    } else {
-      runtime_options.push_back(std::make_pair(boot_image_option_, nullptr));
-    }
-    for (size_t i = 0; i < runtime_args_.size(); i++) {
-      runtime_options.push_back(std::make_pair(runtime_args_[i], nullptr));
+
+    if (!PrepareImageClasses() || !PrepareCompiledClasses() || !PrepareCompiledMethods()) {
+      return false;
     }
 
     verification_results_.reset(new VerificationResults(compiler_options_.get()));
@@ -1037,23 +1027,15 @@
         IsBootImage() ?
             CompilerCallbacks::CallbackMode::kCompileBootImage :
             CompilerCallbacks::CallbackMode::kCompileApp));
-    runtime_options.push_back(std::make_pair("compilercallbacks", callbacks_.get()));
-    runtime_options.push_back(
-        std::make_pair("imageinstructionset", GetInstructionSetString(instruction_set_)));
 
-    // Only allow no boot image for the runtime if we're compiling one. When we compile an app,
-    // we don't want fallback mode, it will abort as we do not push a boot classpath (it might
-    // have been stripped in preopting, anyways).
-    if (!IsBootImage()) {
-      runtime_options.push_back(std::make_pair("-Xno-dex-file-fallback", nullptr));
+    RuntimeArgumentMap runtime_options;
+    if (!PrepareRuntimeOptions(&runtime_options)) {
+      return false;
     }
-    // Disable libsigchain. We don't don't need it during compilation and it prevents us
-    // from getting a statically linked version of dex2oat (because of dlsym and RTLD_NEXT).
-    runtime_options.push_back(std::make_pair("-Xno-sig-chain", nullptr));
 
     {
       TimingLogger::ScopedTiming t_runtime("Create runtime", timings_);
-      if (!CreateRuntime(runtime_options)) {
+      if (!CreateRuntime(std::move(runtime_options))) {
         return false;
       }
     }
@@ -1068,66 +1050,8 @@
     // Whilst we're in native take the opportunity to initialize well known classes.
     WellKnownClasses::Init(self->GetJniEnv());
 
-    // If --image-classes was specified, calculate the full list of classes to include in the image
-    if (image_classes_filename_ != nullptr) {
-      std::string error_msg;
-      if (image_classes_zip_filename_ != nullptr) {
-        image_classes_.reset(ReadImageClassesFromZip(image_classes_zip_filename_,
-                                                     image_classes_filename_,
-                                                     &error_msg));
-      } else {
-        image_classes_.reset(ReadImageClassesFromFile(image_classes_filename_));
-      }
-      if (image_classes_.get() == nullptr) {
-        LOG(ERROR) << "Failed to create list of image classes from '" << image_classes_filename_ <<
-            "': " << error_msg;
-        return false;
-      }
-    } else if (IsBootImage()) {
-      image_classes_.reset(new std::unordered_set<std::string>);
-    }
-    // If --compiled-classes was specified, calculate the full list of classes to compile in the
-    // image.
-    if (compiled_classes_filename_ != nullptr) {
-      std::string error_msg;
-      if (compiled_classes_zip_filename_ != nullptr) {
-        compiled_classes_.reset(ReadImageClassesFromZip(compiled_classes_zip_filename_,
-                                                        compiled_classes_filename_,
-                                                        &error_msg));
-      } else {
-        compiled_classes_.reset(ReadImageClassesFromFile(compiled_classes_filename_));
-      }
-      if (compiled_classes_.get() == nullptr) {
-        LOG(ERROR) << "Failed to create list of compiled classes from '"
-                   << compiled_classes_filename_ << "': " << error_msg;
-        return false;
-      }
-    } else {
-      compiled_classes_.reset(nullptr);  // By default compile everything.
-    }
-    // If --compiled-methods was specified, read the methods to compile from the given file(s).
-    if (compiled_methods_filename_ != nullptr) {
-      std::string error_msg;
-      if (compiled_methods_zip_filename_ != nullptr) {
-        compiled_methods_.reset(ReadCommentedInputFromZip(compiled_methods_zip_filename_,
-                                                          compiled_methods_filename_,
-                                                          nullptr,            // No post-processing.
-                                                          &error_msg));
-      } else {
-        compiled_methods_.reset(ReadCommentedInputFromFile(compiled_methods_filename_,
-                                                           nullptr));         // No post-processing.
-      }
-      if (compiled_methods_.get() == nullptr) {
-        LOG(ERROR) << "Failed to create list of compiled methods from '"
-            << compiled_methods_filename_ << "': " << error_msg;
-        return false;
-      }
-    } else {
-      compiled_methods_.reset(nullptr);  // By default compile everything.
-    }
-
     ClassLinker* const class_linker = Runtime::Current()->GetClassLinker();
-    if (boot_image_option_.empty()) {
+    if (boot_image_filename_.empty()) {
       dex_files_ = class_linker->GetBootClassPath();
     } else {
       TimingLogger::ScopedTiming t_dex("Opening dex files", timings_);
@@ -1164,22 +1088,7 @@
 
       constexpr bool kSaveDexInput = false;
       if (kSaveDexInput) {
-        for (size_t i = 0; i < dex_files_.size(); ++i) {
-          const DexFile* dex_file = dex_files_[i];
-          std::string tmp_file_name(StringPrintf("/data/local/tmp/dex2oat.%d.%zd.dex",
-                                                 getpid(), i));
-          std::unique_ptr<File> tmp_file(OS::CreateEmptyFile(tmp_file_name.c_str()));
-          if (tmp_file.get() == nullptr) {
-            PLOG(ERROR) << "Failed to open file " << tmp_file_name
-                << ". Try: adb shell chmod 777 /data/local/tmp";
-            continue;
-          }
-          // This is just dumping files for debugging. Ignore errors, and leave remnants.
-          UNUSED(tmp_file->WriteFully(dex_file->Begin(), dex_file->Size()));
-          UNUSED(tmp_file->Flush());
-          UNUSED(tmp_file->Close());
-          LOG(INFO) << "Wrote input to " << tmp_file_name;
-        }
+        SaveDexInput();
       }
     }
     // Ensure opened dex files are writable for dex-to-dex transformations. Also ensure that
@@ -1238,16 +1147,13 @@
     jobject class_path_class_loader = nullptr;
     Thread* self = Thread::Current();
 
-    if (!boot_image_option_.empty()) {
+    if (!boot_image_filename_.empty()) {
       ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
       OpenClassPathFiles(runtime_->GetClassPathString(), dex_files_, &class_path_files_);
       ScopedObjectAccess soa(self);
 
       // Classpath: first the class-path given.
-      std::vector<const DexFile*> class_path_files;
-      for (auto& class_path_file : class_path_files_) {
-        class_path_files.push_back(class_path_file.get());
-      }
+      std::vector<const DexFile*> class_path_files = MakeNonOwningPointerVector(class_path_files_);
 
       // Store the classpath we have right now.
       key_value_store_->Put(OatHeader::kClassPathKey,
@@ -1432,14 +1338,9 @@
       elf_writer->EndText(text);
 
       elf_writer->SetBssSize(oat_writer->GetBssSize());
-
       elf_writer->WriteDynamicSection();
-
-      ArrayRef<const dwarf::MethodDebugInfo> method_infos(oat_writer->GetMethodDebugInfo());
-      elf_writer->WriteDebugInfo(method_infos);
-
-      ArrayRef<const uintptr_t> patch_locations(oat_writer->GetAbsolutePatchLocations());
-      elf_writer->WritePatchLocations(patch_locations);
+      elf_writer->WriteDebugInfo(oat_writer->GetMethodDebugInfo());
+      elf_writer->WritePatchLocations(oat_writer->GetAbsolutePatchLocations());
 
       if (!elf_writer->End()) {
         LOG(ERROR) << "Failed to write ELF file " << oat_file_->GetPath();
@@ -1552,6 +1453,16 @@
   }
 
  private:
+  template <typename T>
+  static std::vector<T*> MakeNonOwningPointerVector(const std::vector<std::unique_ptr<T>>& src) {
+    std::vector<T*> result;
+    result.reserve(src.size());
+    for (const std::unique_ptr<T>& t : src) {
+      result.push_back(t.get());
+    }
+    return result;
+  }
+
   static size_t OpenDexFiles(const std::vector<const char*>& dex_filenames,
                              const std::vector<const char*>& dex_locations,
                              std::vector<std::unique_ptr<const DexFile>>* dex_files) {
@@ -1612,10 +1523,138 @@
     }
   }
 
+  bool PrepareImageClasses() {
+    // If --image-classes was specified, calculate the full list of classes to include in the image.
+    if (image_classes_filename_ != nullptr) {
+      image_classes_ =
+          ReadClasses(image_classes_zip_filename_, image_classes_filename_, "image");
+      if (image_classes_ == nullptr) {
+        return false;
+      }
+    } else if (IsBootImage()) {
+      image_classes_.reset(new std::unordered_set<std::string>);
+    }
+    return true;
+  }
+
+  bool PrepareCompiledClasses() {
+    // If --compiled-classes was specified, calculate the full list of classes to compile in the
+    // image.
+    if (compiled_classes_filename_ != nullptr) {
+      compiled_classes_ =
+          ReadClasses(compiled_classes_zip_filename_, compiled_classes_filename_, "compiled");
+      if (compiled_classes_ == nullptr) {
+        return false;
+      }
+    } else {
+      compiled_classes_.reset(nullptr);  // By default compile everything.
+    }
+    return true;
+  }
+
+  static std::unique_ptr<std::unordered_set<std::string>> ReadClasses(const char* zip_filename,
+                                                                      const char* classes_filename,
+                                                                      const char* tag) {
+    std::unique_ptr<std::unordered_set<std::string>> classes;
+    std::string error_msg;
+    if (zip_filename != nullptr) {
+      classes.reset(ReadImageClassesFromZip(zip_filename, classes_filename, &error_msg));
+    } else {
+      classes.reset(ReadImageClassesFromFile(classes_filename));
+    }
+    if (classes == nullptr) {
+      LOG(ERROR) << "Failed to create list of " << tag << " classes from '"
+                 << classes_filename << "': " << error_msg;
+    }
+    return classes;
+  }
+
+  bool PrepareCompiledMethods() {
+    // If --compiled-methods was specified, read the methods to compile from the given file(s).
+    if (compiled_methods_filename_ != nullptr) {
+      std::string error_msg;
+      if (compiled_methods_zip_filename_ != nullptr) {
+        compiled_methods_.reset(ReadCommentedInputFromZip(compiled_methods_zip_filename_,
+                                                          compiled_methods_filename_,
+                                                          nullptr,            // No post-processing.
+                                                          &error_msg));
+      } else {
+        compiled_methods_.reset(ReadCommentedInputFromFile(compiled_methods_filename_,
+                                                           nullptr));         // No post-processing.
+      }
+      if (compiled_methods_.get() == nullptr) {
+        LOG(ERROR) << "Failed to create list of compiled methods from '"
+            << compiled_methods_filename_ << "': " << error_msg;
+        return false;
+      }
+    } else {
+      compiled_methods_.reset(nullptr);  // By default compile everything.
+    }
+    return true;
+  }
+
+  void SaveDexInput() {
+    for (size_t i = 0; i < dex_files_.size(); ++i) {
+      const DexFile* dex_file = dex_files_[i];
+      std::string tmp_file_name(StringPrintf("/data/local/tmp/dex2oat.%d.%zd.dex",
+                                             getpid(), i));
+      std::unique_ptr<File> tmp_file(OS::CreateEmptyFile(tmp_file_name.c_str()));
+      if (tmp_file.get() == nullptr) {
+        PLOG(ERROR) << "Failed to open file " << tmp_file_name
+            << ". Try: adb shell chmod 777 /data/local/tmp";
+        continue;
+      }
+      // This is just dumping files for debugging. Ignore errors, and leave remnants.
+      UNUSED(tmp_file->WriteFully(dex_file->Begin(), dex_file->Size()));
+      UNUSED(tmp_file->Flush());
+      UNUSED(tmp_file->Close());
+      LOG(INFO) << "Wrote input to " << tmp_file_name;
+    }
+  }
+
+  bool PrepareRuntimeOptions(RuntimeArgumentMap* runtime_options) {
+    RuntimeOptions raw_options;
+    if (boot_image_filename_.empty()) {
+      std::string boot_class_path = "-Xbootclasspath:";
+      boot_class_path += Join(dex_filenames_, ':');
+      raw_options.push_back(std::make_pair(boot_class_path, nullptr));
+      std::string boot_class_path_locations = "-Xbootclasspath-locations:";
+      boot_class_path_locations += Join(dex_locations_, ':');
+      raw_options.push_back(std::make_pair(boot_class_path_locations, nullptr));
+    } else {
+      std::string boot_image_option = "-Ximage:";
+      boot_image_option += boot_image_filename_;
+      raw_options.push_back(std::make_pair(boot_image_option, nullptr));
+    }
+    for (size_t i = 0; i < runtime_args_.size(); i++) {
+      raw_options.push_back(std::make_pair(runtime_args_[i], nullptr));
+    }
+
+    raw_options.push_back(std::make_pair("compilercallbacks", callbacks_.get()));
+    raw_options.push_back(
+        std::make_pair("imageinstructionset", GetInstructionSetString(instruction_set_)));
+
+    // Only allow no boot image for the runtime if we're compiling one. When we compile an app,
+    // we don't want fallback mode, it will abort as we do not push a boot classpath (it might
+    // have been stripped in preopting, anyways).
+    if (!IsBootImage()) {
+      raw_options.push_back(std::make_pair("-Xno-dex-file-fallback", nullptr));
+    }
+    // Disable libsigchain. We don't don't need it during compilation and it prevents us
+    // from getting a statically linked version of dex2oat (because of dlsym and RTLD_NEXT).
+    raw_options.push_back(std::make_pair("-Xno-sig-chain", nullptr));
+
+    if (!Runtime::ParseOptions(raw_options, false, runtime_options)) {
+      LOG(ERROR) << "Failed to parse runtime options";
+      return false;
+    }
+    return true;
+  }
+
   // Create a runtime necessary for compilation.
-  bool CreateRuntime(const RuntimeOptions& runtime_options)
+  bool CreateRuntime(RuntimeArgumentMap&& runtime_options)
       SHARED_TRYLOCK_FUNCTION(true, Locks::mutator_lock_) {
-    if (!Runtime::Create(runtime_options, false)) {
+    if (!Runtime::Create(std::move(runtime_options))) {
       LOG(ERROR) << "Failed to create runtime";
       return false;
     }
@@ -1812,7 +1851,7 @@
   std::vector<const char*> dex_locations_;
   int zip_fd_;
   std::string zip_location_;
-  std::string boot_image_option_;
+  std::string boot_image_filename_;
   std::vector<const char*> runtime_args_;
   std::string image_filename_;
   uintptr_t image_base_;
diff --git a/runtime/base/dchecked_vector.h b/runtime/base/dchecked_vector.h
index 2bd12df..51dfba8 100644
--- a/runtime/base/dchecked_vector.h
+++ b/runtime/base/dchecked_vector.h
@@ -33,7 +33,7 @@
 // but we do not use exceptions, so this accessor is deliberately hidden.
 // Note: The common pattern &v[0] used to retrieve pointer to the data is not
 // valid for an empty dchecked_vector<>. Use data() to avoid checking empty().
-template <typename T, typename Alloc>
+template <typename T, typename Alloc = std::allocator<T>>
 class dchecked_vector : private std::vector<T, Alloc> {
  private:
   // std::vector<> has a slightly different specialization for bool. We don't provide that.
diff --git a/runtime/oat.cc b/runtime/oat.cc
index 40aca0d..c787b9a 100644
--- a/runtime/oat.cc
+++ b/runtime/oat.cc
@@ -45,9 +45,7 @@
 
 OatHeader* OatHeader::Create(InstructionSet instruction_set,
                              const InstructionSetFeatures* instruction_set_features,
-                             const std::vector<const DexFile*>* dex_files,
-                             uint32_t image_file_location_oat_checksum,
-                             uint32_t image_file_location_oat_data_begin,
+                             uint32_t dex_file_count,
                              const SafeMap<std::string, std::string>* variable_data) {
   // Estimate size of optional data.
   size_t needed_size = ComputeOatHeaderSize(variable_data);
@@ -58,18 +56,29 @@
   // Create the OatHeader in-place.
   return new (memory) OatHeader(instruction_set,
                                 instruction_set_features,
-                                dex_files,
-                                image_file_location_oat_checksum,
-                                image_file_location_oat_data_begin,
+                                dex_file_count,
                                 variable_data);
 }
 
 OatHeader::OatHeader(InstructionSet instruction_set,
                      const InstructionSetFeatures* instruction_set_features,
-                     const std::vector<const DexFile*>* dex_files,
-                     uint32_t image_file_location_oat_checksum,
-                     uint32_t image_file_location_oat_data_begin,
-                     const SafeMap<std::string, std::string>* variable_data) {
+                     uint32_t dex_file_count,
+                     const SafeMap<std::string, std::string>* variable_data)
+    : adler32_checksum_(adler32(0L, Z_NULL, 0)),
+      instruction_set_(instruction_set),
+      instruction_set_features_bitmap_(instruction_set_features->AsBitmap()),
+      dex_file_count_(dex_file_count),
+      executable_offset_(0),
+      interpreter_to_interpreter_bridge_offset_(0),
+      interpreter_to_compiled_code_bridge_offset_(0),
+      jni_dlsym_lookup_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),
+      image_patch_delta_(0),
+      image_file_location_oat_checksum_(0),
+      image_file_location_oat_data_begin_(0) {
   // Don't want asserts in header as they would be checked in each file that includes it. But the
   // fields are private, so we check inside a method.
   static_assert(sizeof(magic_) == sizeof(kOatMagic),
@@ -79,46 +88,11 @@
 
   memcpy(magic_, kOatMagic, sizeof(kOatMagic));
   memcpy(version_, kOatVersion, sizeof(kOatVersion));
-  executable_offset_ = 0;
-  image_patch_delta_ = 0;
-
-  adler32_checksum_ = adler32(0L, Z_NULL, 0);
 
   CHECK_NE(instruction_set, kNone);
-  instruction_set_ = instruction_set;
-  UpdateChecksum(&instruction_set_, sizeof(instruction_set_));
-
-  instruction_set_features_bitmap_ = instruction_set_features->AsBitmap();
-  UpdateChecksum(&instruction_set_features_bitmap_, sizeof(instruction_set_features_bitmap_));
-
-  dex_file_count_ = dex_files->size();
-  UpdateChecksum(&dex_file_count_, sizeof(dex_file_count_));
-
-  image_file_location_oat_checksum_ = image_file_location_oat_checksum;
-  UpdateChecksum(&image_file_location_oat_checksum_, sizeof(image_file_location_oat_checksum_));
-
-  CHECK_ALIGNED(image_file_location_oat_data_begin, kPageSize);
-  image_file_location_oat_data_begin_ = image_file_location_oat_data_begin;
-  UpdateChecksum(&image_file_location_oat_data_begin_, sizeof(image_file_location_oat_data_begin_));
 
   // Flatten the map. Will also update variable_size_data_size_.
   Flatten(variable_data);
-
-  // Update checksum for variable data size.
-  UpdateChecksum(&key_value_store_size_, sizeof(key_value_store_size_));
-
-  // Update for data, if existing.
-  if (key_value_store_size_ > 0U) {
-    UpdateChecksum(&key_value_store_, key_value_store_size_);
-  }
-
-  interpreter_to_interpreter_bridge_offset_ = 0;
-  interpreter_to_compiled_code_bridge_offset_ = 0;
-  jni_dlsym_lookup_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;
 }
 
 bool OatHeader::IsValid() const {
@@ -175,6 +149,37 @@
   return adler32_checksum_;
 }
 
+void OatHeader::UpdateChecksumWithHeaderData() {
+  UpdateChecksum(&instruction_set_, sizeof(instruction_set_));
+  UpdateChecksum(&instruction_set_features_bitmap_, sizeof(instruction_set_features_bitmap_));
+  UpdateChecksum(&dex_file_count_, sizeof(dex_file_count_));
+  UpdateChecksum(&image_file_location_oat_checksum_, sizeof(image_file_location_oat_checksum_));
+  UpdateChecksum(&image_file_location_oat_data_begin_, sizeof(image_file_location_oat_data_begin_));
+
+  // Update checksum for variable data size.
+  UpdateChecksum(&key_value_store_size_, sizeof(key_value_store_size_));
+
+  // Update for data, if existing.
+  if (key_value_store_size_ > 0U) {
+    UpdateChecksum(&key_value_store_, key_value_store_size_);
+  }
+
+  UpdateChecksum(&executable_offset_, sizeof(executable_offset_));
+  UpdateChecksum(&interpreter_to_interpreter_bridge_offset_,
+                 sizeof(interpreter_to_interpreter_bridge_offset_));
+  UpdateChecksum(&interpreter_to_compiled_code_bridge_offset_,
+                 sizeof(interpreter_to_compiled_code_bridge_offset_));
+  UpdateChecksum(&jni_dlsym_lookup_offset_, sizeof(jni_dlsym_lookup_offset_));
+  UpdateChecksum(&quick_generic_jni_trampoline_offset_,
+                 sizeof(quick_generic_jni_trampoline_offset_));
+  UpdateChecksum(&quick_imt_conflict_trampoline_offset_,
+                 sizeof(quick_imt_conflict_trampoline_offset_));
+  UpdateChecksum(&quick_resolution_trampoline_offset_,
+                 sizeof(quick_resolution_trampoline_offset_));
+  UpdateChecksum(&quick_to_interpreter_bridge_offset_,
+                 sizeof(quick_to_interpreter_bridge_offset_));
+}
+
 void OatHeader::UpdateChecksum(const void* data, size_t length) {
   DCHECK(IsValid());
   const uint8_t* bytes = reinterpret_cast<const uint8_t*>(data);
@@ -205,7 +210,6 @@
   DCHECK_EQ(executable_offset_, 0U);
 
   executable_offset_ = executable_offset;
-  UpdateChecksum(&executable_offset_, sizeof(executable_offset));
 }
 
 const void* OatHeader::GetInterpreterToInterpreterBridge() const {
@@ -225,7 +229,6 @@
   DCHECK_EQ(interpreter_to_interpreter_bridge_offset_, 0U) << offset;
 
   interpreter_to_interpreter_bridge_offset_ = offset;
-  UpdateChecksum(&interpreter_to_interpreter_bridge_offset_, sizeof(offset));
 }
 
 const void* OatHeader::GetInterpreterToCompiledCodeBridge() const {
@@ -244,7 +247,6 @@
   DCHECK_EQ(interpreter_to_compiled_code_bridge_offset_, 0U) << offset;
 
   interpreter_to_compiled_code_bridge_offset_ = offset;
-  UpdateChecksum(&interpreter_to_compiled_code_bridge_offset_, sizeof(offset));
 }
 
 const void* OatHeader::GetJniDlsymLookup() const {
@@ -263,7 +265,6 @@
   DCHECK_EQ(jni_dlsym_lookup_offset_, 0U) << offset;
 
   jni_dlsym_lookup_offset_ = offset;
-  UpdateChecksum(&jni_dlsym_lookup_offset_, sizeof(offset));
 }
 
 const void* OatHeader::GetQuickGenericJniTrampoline() const {
@@ -282,7 +283,6 @@
   DCHECK_EQ(quick_generic_jni_trampoline_offset_, 0U) << offset;
 
   quick_generic_jni_trampoline_offset_ = offset;
-  UpdateChecksum(&quick_generic_jni_trampoline_offset_, sizeof(offset));
 }
 
 const void* OatHeader::GetQuickImtConflictTrampoline() const {
@@ -301,7 +301,6 @@
   DCHECK_EQ(quick_imt_conflict_trampoline_offset_, 0U) << offset;
 
   quick_imt_conflict_trampoline_offset_ = offset;
-  UpdateChecksum(&quick_imt_conflict_trampoline_offset_, sizeof(offset));
 }
 
 const void* OatHeader::GetQuickResolutionTrampoline() const {
@@ -320,7 +319,6 @@
   DCHECK_EQ(quick_resolution_trampoline_offset_, 0U) << offset;
 
   quick_resolution_trampoline_offset_ = offset;
-  UpdateChecksum(&quick_resolution_trampoline_offset_, sizeof(offset));
 }
 
 const void* OatHeader::GetQuickToInterpreterBridge() const {
@@ -339,7 +337,6 @@
   DCHECK_EQ(quick_to_interpreter_bridge_offset_, 0U) << offset;
 
   quick_to_interpreter_bridge_offset_ = offset;
-  UpdateChecksum(&quick_to_interpreter_bridge_offset_, sizeof(offset));
 }
 
 int32_t OatHeader::GetImagePatchDelta() const {
@@ -367,11 +364,22 @@
   return image_file_location_oat_checksum_;
 }
 
+void OatHeader::SetImageFileLocationOatChecksum(uint32_t image_file_location_oat_checksum) {
+  CHECK(IsValid());
+  image_file_location_oat_checksum_ = image_file_location_oat_checksum;
+}
+
 uint32_t OatHeader::GetImageFileLocationOatDataBegin() const {
   CHECK(IsValid());
   return image_file_location_oat_data_begin_;
 }
 
+void OatHeader::SetImageFileLocationOatDataBegin(uint32_t image_file_location_oat_data_begin) {
+  CHECK(IsValid());
+  CHECK_ALIGNED(image_file_location_oat_data_begin, kPageSize);
+  image_file_location_oat_data_begin_ = image_file_location_oat_data_begin;
+}
+
 uint32_t OatHeader::GetKeyValueStoreSize() const {
   CHECK(IsValid());
   return key_value_store_size_;
diff --git a/runtime/oat.h b/runtime/oat.h
index 5b780c3..a063b2b 100644
--- a/runtime/oat.h
+++ b/runtime/oat.h
@@ -45,15 +45,14 @@
 
   static OatHeader* Create(InstructionSet instruction_set,
                            const InstructionSetFeatures* instruction_set_features,
-                           const std::vector<const DexFile*>* dex_files,
-                           uint32_t image_file_location_oat_checksum,
-                           uint32_t image_file_location_oat_data_begin,
+                           uint32_t dex_file_count,
                            const SafeMap<std::string, std::string>* variable_data);
 
   bool IsValid() const;
   std::string GetValidationErrorMessage() const;
   const char* GetMagic() const;
   uint32_t GetChecksum() const;
+  void UpdateChecksumWithHeaderData();
   void UpdateChecksum(const void* data, size_t length);
   uint32_t GetDexFileCount() const {
     DCHECK(IsValid());
@@ -92,8 +91,11 @@
 
   InstructionSet GetInstructionSet() const;
   uint32_t GetInstructionSetFeaturesBitmap() const;
+
   uint32_t GetImageFileLocationOatChecksum() const;
+  void SetImageFileLocationOatChecksum(uint32_t image_file_location_oat_checksum);
   uint32_t GetImageFileLocationOatDataBegin() const;
+  void SetImageFileLocationOatDataBegin(uint32_t image_file_location_oat_data_begin);
 
   uint32_t GetKeyValueStoreSize() const;
   const uint8_t* GetKeyValueStore() const;
@@ -107,9 +109,7 @@
  private:
   OatHeader(InstructionSet instruction_set,
             const InstructionSetFeatures* instruction_set_features,
-            const std::vector<const DexFile*>* dex_files,
-            uint32_t image_file_location_oat_checksum,
-            uint32_t image_file_location_oat_data_begin,
+            uint32_t dex_file_count,
             const SafeMap<std::string, std::string>* variable_data);
 
   // Returns true if the value of the given key is "true", false otherwise.