diff --git a/compiler/elf_builder.h b/compiler/elf_builder.h
index a7461a5..46484b1 100644
--- a/compiler/elf_builder.h
+++ b/compiler/elf_builder.h
@@ -100,12 +100,6 @@
       header_.sh_entsize = entsize;
     }
 
-    ~Section() OVERRIDE {
-      if (started_) {
-        CHECK(finished_);
-      }
-    }
-
     // Start writing of this section.
     void Start() {
       CHECK(!started_);
diff --git a/compiler/image_test.cc b/compiler/image_test.cc
index 6859605..12132c0 100644
--- a/compiler/image_test.cc
+++ b/compiler/image_test.cc
@@ -95,25 +95,37 @@
 
       t.NewTiming("WriteElf");
       SafeMap<std::string, std::string> key_value_store;
-      OatWriter oat_writer(class_linker->GetBootClassPath(),
-                           0,
-                           0,
-                           0,
-                           compiler_driver_.get(),
-                           writer.get(),
-                           /*compiling_boot_image*/true,
-                           &timings,
-                           &key_value_store);
+      const std::vector<const DexFile*>& dex_files = class_linker->GetBootClassPath();
       std::unique_ptr<ElfWriter> elf_writer = CreateElfWriterQuick(
           compiler_driver_->GetInstructionSet(),
           &compiler_driver_->GetCompilerOptions(),
           oat_file.GetFile());
-      bool success = writer->PrepareImageAddressSpace();
-      ASSERT_TRUE(success);
-
       elf_writer->Start();
-
+      OatWriter oat_writer(/*compiling_boot_image*/true, &timings);
       OutputStream* rodata = elf_writer->StartRoData();
+      for (const DexFile* dex_file : dex_files) {
+        ArrayRef<const uint8_t> raw_dex_file(
+            reinterpret_cast<const uint8_t*>(&dex_file->GetHeader()),
+            dex_file->GetHeader().file_size_);
+        oat_writer.AddRawDexFileSource(raw_dex_file,
+                                       dex_file->GetLocation().c_str(),
+                                       dex_file->GetLocationChecksum());
+      }
+      std::unique_ptr<MemMap> opened_dex_files_map;
+      std::vector<std::unique_ptr<const DexFile>> opened_dex_files;
+      bool dex_files_ok = oat_writer.WriteAndOpenDexFiles(
+          rodata,
+          oat_file.GetFile(),
+          compiler_driver_->GetInstructionSet(),
+          compiler_driver_->GetInstructionSetFeatures(),
+          &key_value_store,
+          &opened_dex_files_map,
+          &opened_dex_files);
+      ASSERT_TRUE(dex_files_ok);
+      oat_writer.PrepareLayout(compiler_driver_.get(), writer.get(), dex_files);
+      bool image_space_ok = writer->PrepareImageAddressSpace();
+      ASSERT_TRUE(image_space_ok);
+
       bool rodata_ok = oat_writer.WriteRodata(rodata);
       ASSERT_TRUE(rodata_ok);
       elf_writer->EndRoData(rodata);
@@ -123,12 +135,15 @@
       ASSERT_TRUE(text_ok);
       elf_writer->EndText(text);
 
+      bool header_ok = oat_writer.WriteHeader(elf_writer->GetStream(), 0u, 0u, 0u);
+      ASSERT_TRUE(header_ok);
+
       elf_writer->SetBssSize(oat_writer.GetBssSize());
       elf_writer->WriteDynamicSection();
       elf_writer->WriteDebugInfo(oat_writer.GetMethodDebugInfo());
       elf_writer->WritePatchLocations(oat_writer.GetAbsolutePatchLocations());
 
-      success = elf_writer->End();
+      bool success = elf_writer->End();
 
       ASSERT_TRUE(success);
     }
diff --git a/compiler/oat_test.cc b/compiler/oat_test.cc
index 9f7ffa5..1fd5bdf 100644
--- a/compiler/oat_test.cc
+++ b/compiler/oat_test.cc
@@ -38,6 +38,7 @@
 #include "oat_file-inl.h"
 #include "oat_writer.h"
 #include "scoped_thread_state_change.h"
+#include "utils/test_dex_file_builder.h"
 
 namespace art {
 
@@ -129,23 +130,74 @@
                 const std::vector<const DexFile*>& dex_files,
                 SafeMap<std::string, std::string>& key_value_store) {
     TimingLogger timings("WriteElf", false, false);
-    OatWriter oat_writer(dex_files,
-                         42U,
-                         4096U,
-                         0,
-                         compiler_driver_.get(),
-                         nullptr,
-                         /*compiling_boot_image*/false,
-                         &timings,
-                         &key_value_store);
+    OatWriter oat_writer(/*compiling_boot_image*/false, &timings);
+    for (const DexFile* dex_file : dex_files) {
+      ArrayRef<const uint8_t> raw_dex_file(
+          reinterpret_cast<const uint8_t*>(&dex_file->GetHeader()),
+          dex_file->GetHeader().file_size_);
+      if (!oat_writer.AddRawDexFileSource(raw_dex_file,
+                                          dex_file->GetLocation().c_str(),
+                                          dex_file->GetLocationChecksum())) {
+        return false;
+      }
+    }
+    return DoWriteElf(file, oat_writer, key_value_store);
+  }
+
+  bool WriteElf(File* file,
+                const std::vector<const char*>& dex_filenames,
+                SafeMap<std::string, std::string>& key_value_store) {
+    TimingLogger timings("WriteElf", false, false);
+    OatWriter oat_writer(/*compiling_boot_image*/false, &timings);
+    for (const char* dex_filename : dex_filenames) {
+      if (!oat_writer.AddDexFileSource(dex_filename, dex_filename)) {
+        return false;
+      }
+    }
+    return DoWriteElf(file, oat_writer, key_value_store);
+  }
+
+  bool WriteElf(File* file,
+                ScopedFd&& zip_fd,
+                const char* location,
+                SafeMap<std::string, std::string>& key_value_store) {
+    TimingLogger timings("WriteElf", false, false);
+    OatWriter oat_writer(/*compiling_boot_image*/false, &timings);
+    if (!oat_writer.AddZippedDexFilesSource(std::move(zip_fd), location)) {
+      return false;
+    }
+    return DoWriteElf(file, oat_writer, key_value_store);
+  }
+
+  bool DoWriteElf(File* file,
+                  OatWriter& oat_writer,
+                  SafeMap<std::string, std::string>& key_value_store) {
     std::unique_ptr<ElfWriter> elf_writer = CreateElfWriterQuick(
         compiler_driver_->GetInstructionSet(),
         &compiler_driver_->GetCompilerOptions(),
         file);
-
     elf_writer->Start();
-
     OutputStream* rodata = elf_writer->StartRoData();
+    std::unique_ptr<MemMap> opened_dex_files_map;
+    std::vector<std::unique_ptr<const DexFile>> opened_dex_files;
+    if (!oat_writer.WriteAndOpenDexFiles(rodata,
+                                         file,
+                                         compiler_driver_->GetInstructionSet(),
+                                         compiler_driver_->GetInstructionSetFeatures(),
+                                         &key_value_store,
+                                         &opened_dex_files_map,
+                                         &opened_dex_files)) {
+      return false;
+    }
+    Runtime* runtime = Runtime::Current();
+    ClassLinker* const class_linker = runtime->GetClassLinker();
+    std::vector<const DexFile*> dex_files;
+    for (const std::unique_ptr<const DexFile>& dex_file : opened_dex_files) {
+      dex_files.push_back(dex_file.get());
+      ScopedObjectAccess soa(Thread::Current());
+      class_linker->RegisterDexFile(*dex_file, runtime->GetLinearAlloc());
+    }
+    oat_writer.PrepareLayout(compiler_driver_.get(), nullptr, dex_files);
     if (!oat_writer.WriteRodata(rodata)) {
       return false;
     }
@@ -157,6 +209,10 @@
     }
     elf_writer->EndText(text);
 
+    if (!oat_writer.WriteHeader(elf_writer->GetStream(), 42U, 4096U, 0)) {
+      return false;
+    }
+
     elf_writer->SetBssSize(oat_writer.GetBssSize());
     elf_writer->WriteDynamicSection();
     elf_writer->WriteDebugInfo(oat_writer.GetMethodDebugInfo());
@@ -169,6 +225,117 @@
   std::unique_ptr<QuickCompilerCallbacks> callbacks_;
 };
 
+class ZipBuilder {
+ public:
+  explicit ZipBuilder(File* zip_file) : zip_file_(zip_file) { }
+
+  bool AddFile(const char* location, const void* data, size_t size) {
+    off_t offset = lseek(zip_file_->Fd(), 0, SEEK_CUR);
+    if (offset == static_cast<off_t>(-1)) {
+      return false;
+    }
+
+    ZipFileHeader file_header;
+    file_header.crc32 = crc32(0u, reinterpret_cast<const Bytef*>(data), size);
+    file_header.compressed_size = size;
+    file_header.uncompressed_size = size;
+    file_header.filename_length = strlen(location);
+
+    if (!zip_file_->WriteFully(&file_header, sizeof(file_header)) ||
+        !zip_file_->WriteFully(location, file_header.filename_length) ||
+        !zip_file_->WriteFully(data, size)) {
+      return false;
+    }
+
+    CentralDirectoryFileHeader cdfh;
+    cdfh.crc32 = file_header.crc32;
+    cdfh.compressed_size = size;
+    cdfh.uncompressed_size = size;
+    cdfh.filename_length = file_header.filename_length;
+    cdfh.relative_offset_of_local_file_header = offset;
+    file_data_.push_back(FileData { cdfh, location });
+    return true;
+  }
+
+  bool Finish() {
+    off_t offset = lseek(zip_file_->Fd(), 0, SEEK_CUR);
+    if (offset == static_cast<off_t>(-1)) {
+      return false;
+    }
+
+    size_t central_directory_size = 0u;
+    for (const FileData& file_data : file_data_) {
+      if (!zip_file_->WriteFully(&file_data.cdfh, sizeof(file_data.cdfh)) ||
+          !zip_file_->WriteFully(file_data.location, file_data.cdfh.filename_length)) {
+        return false;
+      }
+      central_directory_size += sizeof(file_data.cdfh) + file_data.cdfh.filename_length;
+    }
+    EndOfCentralDirectoryRecord eocd_record;
+    eocd_record.number_of_central_directory_records_on_this_disk = file_data_.size();
+    eocd_record.total_number_of_central_directory_records = file_data_.size();
+    eocd_record.size_of_central_directory = central_directory_size;
+    eocd_record.offset_of_start_of_central_directory = offset;
+    return
+        zip_file_->WriteFully(&eocd_record, sizeof(eocd_record)) &&
+        zip_file_->Flush() == 0;
+  }
+
+ private:
+  struct PACKED(1) ZipFileHeader {
+    uint32_t signature = 0x04034b50;
+    uint16_t version_needed_to_extract = 10;
+    uint16_t general_purpose_bit_flag = 0;
+    uint16_t compression_method = 0;            // 0 = store only.
+    uint16_t file_last_modification_time = 0u;
+    uint16_t file_last_modification_date = 0u;
+    uint32_t crc32;
+    uint32_t compressed_size;
+    uint32_t uncompressed_size;
+    uint16_t filename_length;
+    uint16_t extra_field_length = 0u;           // No extra fields.
+  };
+
+  struct PACKED(1) CentralDirectoryFileHeader {
+    uint32_t signature = 0x02014b50;
+    uint16_t version_made_by = 10;
+    uint16_t version_needed_to_extract = 10;
+    uint16_t general_purpose_bit_flag = 0;
+    uint16_t compression_method = 0;            // 0 = store only.
+    uint16_t file_last_modification_time = 0u;
+    uint16_t file_last_modification_date = 0u;
+    uint32_t crc32;
+    uint32_t compressed_size;
+    uint32_t uncompressed_size;
+    uint16_t filename_length;
+    uint16_t extra_field_length = 0u;           // No extra fields.
+    uint16_t file_comment_length = 0u;          // No file comment.
+    uint16_t disk_number_where_file_starts = 0u;
+    uint16_t internal_file_attributes = 0u;
+    uint32_t external_file_attributes = 0u;
+    uint32_t relative_offset_of_local_file_header;
+  };
+
+  struct PACKED(1) EndOfCentralDirectoryRecord {
+    uint32_t signature = 0x06054b50;
+    uint16_t number_of_this_disk = 0u;
+    uint16_t disk_where_central_directory_starts = 0u;
+    uint16_t number_of_central_directory_records_on_this_disk;
+    uint16_t total_number_of_central_directory_records;
+    uint32_t size_of_central_directory;
+    uint32_t offset_of_start_of_central_directory;
+    uint16_t comment_length = 0u;               // No file comment.
+  };
+
+  struct FileData {
+    CentralDirectoryFileHeader cdfh;
+    const char* location;
+  };
+
+  File* zip_file_;
+  std::vector<FileData> file_data_;
+};
+
 TEST_F(OatTest, WriteRead) {
   TimingLogger timings("OatTest::WriteRead", false, false);
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
@@ -329,4 +496,189 @@
   EXPECT_LT(static_cast<size_t>(oat_file->Size()), static_cast<size_t>(tmp.GetFile()->GetLength()));
 }
 
+TEST_F(OatTest, DexFileInput) {
+  TimingLogger timings("OatTest::DexFileInput", false, false);
+
+  std::vector<const char*> input_filenames;
+
+  ScratchFile dex_file1;
+  TestDexFileBuilder builder1;
+  builder1.AddField("Lsome.TestClass;", "int", "someField");
+  builder1.AddMethod("Lsome.TestClass;", "()I", "foo");
+  std::unique_ptr<const DexFile> dex_file1_data = builder1.Build(dex_file1.GetFilename());
+  bool success = dex_file1.GetFile()->WriteFully(&dex_file1_data->GetHeader(),
+                                                 dex_file1_data->GetHeader().file_size_);
+  ASSERT_TRUE(success);
+  success = dex_file1.GetFile()->Flush() == 0;
+  ASSERT_TRUE(success);
+  input_filenames.push_back(dex_file1.GetFilename().c_str());
+
+  ScratchFile dex_file2;
+  TestDexFileBuilder builder2;
+  builder2.AddField("Land.AnotherTestClass;", "boolean", "someOtherField");
+  builder2.AddMethod("Land.AnotherTestClass;", "()J", "bar");
+  std::unique_ptr<const DexFile> dex_file2_data = builder2.Build(dex_file2.GetFilename());
+  success = dex_file2.GetFile()->WriteFully(&dex_file2_data->GetHeader(),
+                                            dex_file2_data->GetHeader().file_size_);
+  ASSERT_TRUE(success);
+  success = dex_file2.GetFile()->Flush() == 0;
+  ASSERT_TRUE(success);
+  input_filenames.push_back(dex_file2.GetFilename().c_str());
+
+  ScratchFile oat_file;
+  SafeMap<std::string, std::string> key_value_store;
+  key_value_store.Put(OatHeader::kImageLocationKey, "test.art");
+  success = WriteElf(oat_file.GetFile(), input_filenames, key_value_store);
+  ASSERT_TRUE(success);
+
+  std::string error_msg;
+  std::unique_ptr<OatFile> opened_oat_file(OatFile::Open(oat_file.GetFilename(),
+                                                         oat_file.GetFilename(),
+                                                         nullptr,
+                                                         nullptr,
+                                                         false,
+                                                         nullptr,
+                                                         &error_msg));
+  ASSERT_TRUE(opened_oat_file != nullptr);
+  ASSERT_EQ(2u, opened_oat_file->GetOatDexFiles().size());
+  std::unique_ptr<const DexFile> opened_dex_file1 =
+      opened_oat_file->GetOatDexFiles()[0]->OpenDexFile(&error_msg);
+  std::unique_ptr<const DexFile> opened_dex_file2 =
+      opened_oat_file->GetOatDexFiles()[1]->OpenDexFile(&error_msg);
+
+  ASSERT_EQ(dex_file1_data->GetHeader().file_size_, opened_dex_file1->GetHeader().file_size_);
+  ASSERT_EQ(0, memcmp(&dex_file1_data->GetHeader(),
+                      &opened_dex_file1->GetHeader(),
+                      dex_file1_data->GetHeader().file_size_));
+  ASSERT_EQ(dex_file1_data->GetLocation(), opened_dex_file1->GetLocation());
+
+  ASSERT_EQ(dex_file2_data->GetHeader().file_size_, opened_dex_file2->GetHeader().file_size_);
+  ASSERT_EQ(0, memcmp(&dex_file2_data->GetHeader(),
+                      &opened_dex_file2->GetHeader(),
+                      dex_file2_data->GetHeader().file_size_));
+  ASSERT_EQ(dex_file2_data->GetLocation(), opened_dex_file2->GetLocation());
+}
+
+TEST_F(OatTest, ZipFileInput) {
+  TimingLogger timings("OatTest::DexFileInput", false, false);
+
+  ScratchFile zip_file;
+  ZipBuilder zip_builder(zip_file.GetFile());
+
+  ScratchFile dex_file1;
+  TestDexFileBuilder builder1;
+  builder1.AddField("Lsome.TestClass;", "long", "someField");
+  builder1.AddMethod("Lsome.TestClass;", "()D", "foo");
+  std::unique_ptr<const DexFile> dex_file1_data = builder1.Build(dex_file1.GetFilename());
+  bool success = dex_file1.GetFile()->WriteFully(&dex_file1_data->GetHeader(),
+                                                 dex_file1_data->GetHeader().file_size_);
+  ASSERT_TRUE(success);
+  success = dex_file1.GetFile()->Flush() == 0;
+  ASSERT_TRUE(success);
+  success = zip_builder.AddFile("classes.dex",
+                                &dex_file1_data->GetHeader(),
+                                dex_file1_data->GetHeader().file_size_);
+  ASSERT_TRUE(success);
+
+  ScratchFile dex_file2;
+  TestDexFileBuilder builder2;
+  builder2.AddField("Land.AnotherTestClass;", "boolean", "someOtherField");
+  builder2.AddMethod("Land.AnotherTestClass;", "()J", "bar");
+  std::unique_ptr<const DexFile> dex_file2_data = builder2.Build(dex_file2.GetFilename());
+  success = dex_file2.GetFile()->WriteFully(&dex_file2_data->GetHeader(),
+                                            dex_file2_data->GetHeader().file_size_);
+  ASSERT_TRUE(success);
+  success = dex_file2.GetFile()->Flush() == 0;
+  ASSERT_TRUE(success);
+  success = zip_builder.AddFile("classes2.dex",
+                                &dex_file2_data->GetHeader(),
+                                dex_file2_data->GetHeader().file_size_);
+  ASSERT_TRUE(success);
+
+  success = zip_builder.Finish();
+  ASSERT_TRUE(success) << strerror(errno);
+
+  SafeMap<std::string, std::string> key_value_store;
+  key_value_store.Put(OatHeader::kImageLocationKey, "test.art");
+  {
+    // Test using the AddDexFileSource() interface with the zip file.
+    std::vector<const char*> input_filenames { zip_file.GetFilename().c_str() };  // NOLINT [readability/braces] [4]
+
+    ScratchFile oat_file;
+    success = WriteElf(oat_file.GetFile(), input_filenames, key_value_store);
+    ASSERT_TRUE(success);
+
+    std::string error_msg;
+    std::unique_ptr<OatFile> opened_oat_file(OatFile::Open(oat_file.GetFilename(),
+                                                           oat_file.GetFilename(),
+                                                           nullptr,
+                                                           nullptr,
+                                                           false,
+                                                           nullptr,
+                                                           &error_msg));
+    ASSERT_TRUE(opened_oat_file != nullptr);
+    ASSERT_EQ(2u, opened_oat_file->GetOatDexFiles().size());
+    std::unique_ptr<const DexFile> opened_dex_file1 =
+        opened_oat_file->GetOatDexFiles()[0]->OpenDexFile(&error_msg);
+    std::unique_ptr<const DexFile> opened_dex_file2 =
+        opened_oat_file->GetOatDexFiles()[1]->OpenDexFile(&error_msg);
+
+    ASSERT_EQ(dex_file1_data->GetHeader().file_size_, opened_dex_file1->GetHeader().file_size_);
+    ASSERT_EQ(0, memcmp(&dex_file1_data->GetHeader(),
+                        &opened_dex_file1->GetHeader(),
+                        dex_file1_data->GetHeader().file_size_));
+    ASSERT_EQ(DexFile::GetMultiDexLocation(0, zip_file.GetFilename().c_str()),
+              opened_dex_file1->GetLocation());
+
+    ASSERT_EQ(dex_file2_data->GetHeader().file_size_, opened_dex_file2->GetHeader().file_size_);
+    ASSERT_EQ(0, memcmp(&dex_file2_data->GetHeader(),
+                        &opened_dex_file2->GetHeader(),
+                        dex_file2_data->GetHeader().file_size_));
+    ASSERT_EQ(DexFile::GetMultiDexLocation(1, zip_file.GetFilename().c_str()),
+              opened_dex_file2->GetLocation());
+  }
+
+  {
+    // Test using the AddZipDexFileSource() interface with the zip file handle.
+    ScopedFd zip_fd(dup(zip_file.GetFd()));
+    ASSERT_NE(-1, zip_fd.get());
+
+    ScratchFile oat_file;
+    success = WriteElf(oat_file.GetFile(),
+                       std::move(zip_fd),
+                       zip_file.GetFilename().c_str(),
+                       key_value_store);
+    ASSERT_TRUE(success);
+
+    std::string error_msg;
+    std::unique_ptr<OatFile> opened_oat_file(OatFile::Open(oat_file.GetFilename(),
+                                                           oat_file.GetFilename(),
+                                                           nullptr,
+                                                           nullptr,
+                                                           false,
+                                                           nullptr,
+                                                           &error_msg));
+    ASSERT_TRUE(opened_oat_file != nullptr);
+    ASSERT_EQ(2u, opened_oat_file->GetOatDexFiles().size());
+    std::unique_ptr<const DexFile> opened_dex_file1 =
+        opened_oat_file->GetOatDexFiles()[0]->OpenDexFile(&error_msg);
+    std::unique_ptr<const DexFile> opened_dex_file2 =
+        opened_oat_file->GetOatDexFiles()[1]->OpenDexFile(&error_msg);
+
+    ASSERT_EQ(dex_file1_data->GetHeader().file_size_, opened_dex_file1->GetHeader().file_size_);
+    ASSERT_EQ(0, memcmp(&dex_file1_data->GetHeader(),
+                        &opened_dex_file1->GetHeader(),
+                        dex_file1_data->GetHeader().file_size_));
+    ASSERT_EQ(DexFile::GetMultiDexLocation(0, zip_file.GetFilename().c_str()),
+              opened_dex_file1->GetLocation());
+
+    ASSERT_EQ(dex_file2_data->GetHeader().file_size_, opened_dex_file2->GetHeader().file_size_);
+    ASSERT_EQ(0, memcmp(&dex_file2_data->GetHeader(),
+                        &opened_dex_file2->GetHeader(),
+                        dex_file2_data->GetHeader().file_size_));
+    ASSERT_EQ(DexFile::GetMultiDexLocation(1, zip_file.GetFilename().c_str()),
+              opened_dex_file2->GetLocation());
+  }
+}
+
 }  // namespace art
diff --git a/compiler/oat_writer.cc b/compiler/oat_writer.cc
index 025e35e..c74c41f0 100644
--- a/compiler/oat_writer.cc
+++ b/compiler/oat_writer.cc
@@ -16,12 +16,14 @@
 
 #include "oat_writer.h"
 
+#include <unistd.h>
 #include <zlib.h>
 
 #include "arch/arm64/instruction_set_features_arm64.h"
 #include "art_method-inl.h"
 #include "base/allocator.h"
 #include "base/bit_vector.h"
+#include "base/file_magic.h"
 #include "base/stl_util.h"
 #include "base/unix_file/fd_file.h"
 #include "class_linker.h"
@@ -49,9 +51,77 @@
 #include "type_lookup_table.h"
 #include "utils/dex_cache_arrays_layout-inl.h"
 #include "verifier/method_verifier.h"
+#include "zip_archive.h"
 
 namespace art {
 
+namespace {  // anonymous namespace
+
+typedef DexFile::Header __attribute__((aligned(1))) UnalignedDexFileHeader;
+
+const UnalignedDexFileHeader* AsUnalignedDexFileHeader(const uint8_t* raw_data) {
+    return reinterpret_cast<const UnalignedDexFileHeader*>(raw_data);
+}
+
+}  // anonymous namespace
+
+// Defines the location of the raw dex file to write.
+class OatWriter::DexFileSource {
+ public:
+  explicit DexFileSource(ZipEntry* zip_entry)
+      : type_(kZipEntry), source_(zip_entry) {
+    DCHECK(source_ != nullptr);
+  }
+
+  explicit DexFileSource(File* raw_file)
+      : type_(kRawFile), source_(raw_file) {
+    DCHECK(source_ != nullptr);
+  }
+
+  explicit DexFileSource(const uint8_t* dex_file)
+      : type_(kRawData), source_(dex_file) {
+    DCHECK(source_ != nullptr);
+  }
+
+  bool IsZipEntry() const { return type_ == kZipEntry; }
+  bool IsRawFile() const { return type_ == kRawFile; }
+  bool IsRawData() const { return type_ == kRawData; }
+
+  ZipEntry* GetZipEntry() const {
+    DCHECK(IsZipEntry());
+    DCHECK(source_ != nullptr);
+    return static_cast<ZipEntry*>(const_cast<void*>(source_));
+  }
+
+  File* GetRawFile() const {
+    DCHECK(IsRawFile());
+    DCHECK(source_ != nullptr);
+    return static_cast<File*>(const_cast<void*>(source_));
+  }
+
+  const uint8_t* GetRawData() const {
+    DCHECK(IsRawData());
+    DCHECK(source_ != nullptr);
+    return static_cast<const uint8_t*>(source_);
+  }
+
+  void Clear() {
+    type_ = kNone;
+    source_ = nullptr;
+  }
+
+ private:
+  enum Type {
+    kNone,
+    kZipEntry,
+    kRawFile,
+    kRawData,
+  };
+
+  Type type_;
+  const void* source_;
+};
+
 class OatWriter::OatClass {
  public:
   OatClass(size_t offset,
@@ -116,11 +186,30 @@
 
 class OatWriter::OatDexFile {
  public:
-  OatDexFile(size_t offset, const DexFile& dex_file);
+  OatDexFile(const char* dex_file_location,
+             DexFileSource source,
+             CreateTypeLookupTable create_type_lookup_table);
   OatDexFile(OatDexFile&& src) = default;
 
+  const char* GetLocation() const {
+    return dex_file_location_data_;
+  }
+
+  void ReserveTypeLookupTable(OatWriter* oat_writer);
+  void ReserveClassOffsets(OatWriter* oat_writer);
+
   size_t SizeOf() const;
-  bool Write(OatWriter* oat_writer, OutputStream* out, const size_t file_offset) const;
+  bool Write(OatWriter* oat_writer, OutputStream* out) const;
+  bool WriteClassOffsets(OatWriter* oat_writer, OutputStream* out);
+
+  // The source of the dex file.
+  DexFileSource source_;
+
+  // Whether to create the type lookup table.
+  CreateTypeLookupTable create_type_lookup_table_;
+
+  // Dex file size. Initialized when writing the dex file.
+  size_t dex_file_size_;
 
   // Offset of start of OatDexFile from beginning of OatHeader. It is
   // used to validate file position when writing.
@@ -128,11 +217,13 @@
 
   // Data to write.
   uint32_t dex_file_location_size_;
-  const uint8_t* dex_file_location_data_;
+  const char* dex_file_location_data_;
   uint32_t dex_file_location_checksum_;
   uint32_t dex_file_offset_;
+  uint32_t class_offsets_offset_;
   uint32_t lookup_table_offset_;
-  TypeLookupTable* lookup_table_;  // Owned by the dex file.
+
+  // Data to write to a separate section.
   dchecked_vector<uint32_t> class_offsets_;
 
  private:
@@ -151,26 +242,20 @@
   DCHECK_EQ(static_cast<off_t>(file_offset + offset_), out->Seek(0, kSeekCurrent)) \
     << "file_offset=" << file_offset << " offset_=" << offset_
 
-OatWriter::OatWriter(const std::vector<const DexFile*>& dex_files,
-                     uint32_t image_file_location_oat_checksum,
-                     uintptr_t image_file_location_oat_begin,
-                     int32_t image_patch_delta,
-                     const CompilerDriver* compiler,
-                     ImageWriter* image_writer,
-                     bool compiling_boot_image,
-                     TimingLogger* timings,
-                     SafeMap<std::string, std::string>* key_value_store)
-  : compiler_driver_(compiler),
-    image_writer_(image_writer),
+OatWriter::OatWriter(bool compiling_boot_image, TimingLogger* timings)
+  : write_state_(WriteState::kAddingDexFileSources),
+    timings_(timings),
+    raw_dex_files_(),
+    zip_archives_(),
+    zipped_dex_files_(),
+    zipped_dex_file_locations_(),
+    compiler_driver_(nullptr),
+    image_writer_(nullptr),
     compiling_boot_image_(compiling_boot_image),
-    dex_files_(&dex_files),
+    dex_files_(nullptr),
     size_(0u),
     bss_size_(0u),
     oat_data_offset_(0u),
-    image_file_location_oat_checksum_(image_file_location_oat_checksum),
-    image_file_location_oat_begin_(image_file_location_oat_begin),
-    image_patch_delta_(image_patch_delta),
-    key_value_store_(key_value_store),
     oat_header_(nullptr),
     size_dex_file_alignment_(0),
     size_executable_offset_alignment_(0),
@@ -197,55 +282,192 @@
     size_oat_dex_file_location_data_(0),
     size_oat_dex_file_location_checksum_(0),
     size_oat_dex_file_offset_(0),
+    size_oat_dex_file_class_offsets_offset_(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_offsets_alignment_(0),
+    size_oat_class_offsets_(0),
     size_oat_class_type_(0),
     size_oat_class_status_(0),
     size_oat_class_method_bitmaps_(0),
     size_oat_class_method_offsets_(0),
     method_offset_map_() {
-  CHECK(key_value_store != nullptr);
-  if (compiling_boot_image) {
-    CHECK(image_writer != nullptr);
+}
+
+bool OatWriter::AddDexFileSource(const char* filename,
+                                 const char* location,
+                                 CreateTypeLookupTable create_type_lookup_table) {
+  DCHECK(write_state_ == WriteState::kAddingDexFileSources);
+  uint32_t magic;
+  std::string error_msg;
+  ScopedFd fd(OpenAndReadMagic(filename, &magic, &error_msg));
+  if (fd.get() == -1) {
+    PLOG(ERROR) << "Failed to read magic number from dex file: '" << filename << "'";
+    return false;
+  } else if (IsDexMagic(magic)) {
+    // The file is open for reading, not writing, so it's OK to let the File destructor
+    // close it without checking for explicit Close(), so pass checkUsage = false.
+    raw_dex_files_.emplace_back(new File(fd.release(), location, /* checkUsage */ false));
+    oat_dex_files_.emplace_back(location,
+                                DexFileSource(raw_dex_files_.back().get()),
+                                create_type_lookup_table);
+  } else if (IsZipMagic(magic)) {
+    if (!AddZippedDexFilesSource(std::move(fd), location, create_type_lookup_table)) {
+      return false;
+    }
+  } else {
+    LOG(ERROR) << "Expected valid zip or dex file: '" << filename << "'";
+    return false;
+  }
+  return true;
+}
+
+// Add dex file source(s) from a zip file specified by a file handle.
+bool OatWriter::AddZippedDexFilesSource(ScopedFd&& zip_fd,
+                                        const char* location,
+                                        CreateTypeLookupTable create_type_lookup_table) {
+  DCHECK(write_state_ == WriteState::kAddingDexFileSources);
+  std::string error_msg;
+  zip_archives_.emplace_back(ZipArchive::OpenFromFd(zip_fd.release(), location, &error_msg));
+  ZipArchive* zip_archive = zip_archives_.back().get();
+  if (zip_archive == nullptr) {
+    LOG(ERROR) << "Failed to open zip from file descriptor for '" << location << "': "
+        << error_msg;
+    return false;
+  }
+  for (size_t i = 0; ; ++i) {
+    std::string entry_name = DexFile::GetMultiDexClassesDexName(i);
+    std::unique_ptr<ZipEntry> entry(zip_archive->Find(entry_name.c_str(), &error_msg));
+    if (entry == nullptr) {
+      break;
+    }
+    zipped_dex_files_.push_back(std::move(entry));
+    zipped_dex_file_locations_.push_back(DexFile::GetMultiDexLocation(i, location));
+    const char* full_location = zipped_dex_file_locations_.back().c_str();
+    oat_dex_files_.emplace_back(full_location,
+                                DexFileSource(zipped_dex_files_.back().get()),
+                                create_type_lookup_table);
+  }
+  if (zipped_dex_file_locations_.empty()) {
+    LOG(ERROR) << "No dex files in zip file '" << location << "': " << error_msg;
+    return false;
+  }
+  return true;
+}
+
+// Add dex file source from raw memory.
+bool OatWriter::AddRawDexFileSource(const ArrayRef<const uint8_t>& data,
+                                    const char* location,
+                                    uint32_t location_checksum,
+                                    CreateTypeLookupTable create_type_lookup_table) {
+  DCHECK(write_state_ == WriteState::kAddingDexFileSources);
+  if (data.size() < sizeof(DexFile::Header)) {
+    LOG(ERROR) << "Provided data is shorter than dex file header. size: "
+               << data.size() << " File: " << location;
+    return false;
+  }
+  if (!ValidateDexFileHeader(data.data(), location)) {
+    return false;
+  }
+  const UnalignedDexFileHeader* header = AsUnalignedDexFileHeader(data.data());
+  if (data.size() < header->file_size_) {
+    LOG(ERROR) << "Truncated dex file data. Data size: " << data.size()
+               << " file size from header: " << header->file_size_ << " File: " << location;
+    return false;
+  }
+
+  oat_dex_files_.emplace_back(location, DexFileSource(data.data()), create_type_lookup_table);
+  oat_dex_files_.back().dex_file_location_checksum_ = location_checksum;
+  return true;
+}
+
+dchecked_vector<const char*> OatWriter::GetSourceLocations() const {
+  dchecked_vector<const char*> locations;
+  locations.reserve(oat_dex_files_.size());
+  for (const OatDexFile& oat_dex_file : oat_dex_files_) {
+    locations.push_back(oat_dex_file.GetLocation());
+  }
+  return locations;
+}
+
+bool OatWriter::WriteAndOpenDexFiles(
+    OutputStream* rodata,
+    File* file,
+    InstructionSet instruction_set,
+    const InstructionSetFeatures* instruction_set_features,
+    SafeMap<std::string, std::string>* key_value_store,
+    /*out*/ std::unique_ptr<MemMap>* opened_dex_files_map,
+    /*out*/ std::vector<std::unique_ptr<const DexFile>>* opened_dex_files) {
+  CHECK(write_state_ == WriteState::kAddingDexFileSources);
+
+  size_t offset = InitOatHeader(instruction_set,
+                                instruction_set_features,
+                                dchecked_integral_cast<uint32_t>(oat_dex_files_.size()),
+                                key_value_store);
+  offset = InitOatDexFiles(offset);
+  size_ = offset;
+
+  std::unique_ptr<MemMap> dex_files_map;
+  std::vector<std::unique_ptr<const DexFile>> dex_files;
+  if (!WriteDexFiles(rodata, file)) {
+    return false;
+  }
+  // Reserve space for type lookup tables and update type_lookup_table_offset_.
+  for (OatDexFile& oat_dex_file : oat_dex_files_) {
+    oat_dex_file.ReserveTypeLookupTable(this);
+  }
+  size_t size_after_type_lookup_tables = size_;
+  // Reserve space for class offsets and update class_offsets_offset_.
+  for (OatDexFile& oat_dex_file : oat_dex_files_) {
+    oat_dex_file.ReserveClassOffsets(this);
+  }
+  if (!WriteOatDexFiles(rodata) ||
+      !ExtendForTypeLookupTables(rodata, file, size_after_type_lookup_tables) ||
+      !OpenDexFiles(file, &dex_files_map, &dex_files) ||
+      !WriteTypeLookupTables(dex_files_map.get(), dex_files)) {
+    return false;
+  }
+
+  *opened_dex_files_map = std::move(dex_files_map);
+  *opened_dex_files = std::move(dex_files);
+  write_state_ = WriteState::kPrepareLayout;
+  return true;
+}
+
+void OatWriter::PrepareLayout(const CompilerDriver* compiler,
+                              ImageWriter* image_writer,
+                              const std::vector<const DexFile*>& dex_files) {
+  CHECK(write_state_ == WriteState::kPrepareLayout);
+
+  dex_files_ = &dex_files;
+
+  compiler_driver_ = compiler;
+  image_writer_ = image_writer;
+  if (compiling_boot_image_) {
+    CHECK(image_writer_ != nullptr);
   }
   InstructionSet instruction_set = compiler_driver_->GetInstructionSet();
+  CHECK_EQ(instruction_set, oat_header_->GetInstructionSet());
   const InstructionSetFeatures* features = compiler_driver_->GetInstructionSetFeatures();
   relative_patcher_ = linker::RelativePatcher::Create(instruction_set, features,
                                                       &method_offset_map_);
 
-  size_t offset;
+  uint32_t offset = size_;
   {
-    TimingLogger::ScopedTiming split("InitOatHeader", timings);
-    offset = InitOatHeader();
-  }
-  {
-    TimingLogger::ScopedTiming split("InitOatDexFiles", timings);
-    offset = InitOatDexFiles(offset);
-  }
-  {
-    TimingLogger::ScopedTiming split("InitDexFiles", timings);
-    offset = InitDexFiles(offset);
-  }
-  {
-    TimingLogger::ScopedTiming split("InitLookupTables", timings);
-    offset = InitLookupTables(offset);
-  }
-  {
-    TimingLogger::ScopedTiming split("InitOatClasses", timings);
+    TimingLogger::ScopedTiming split("InitOatClasses", timings_);
     offset = InitOatClasses(offset);
   }
   {
-    TimingLogger::ScopedTiming split("InitOatMaps", timings);
+    TimingLogger::ScopedTiming split("InitOatMaps", timings_);
     offset = InitOatMaps(offset);
   }
   {
-    TimingLogger::ScopedTiming split("InitOatCode", timings);
+    TimingLogger::ScopedTiming split("InitOatCode", timings_);
     offset = InitOatCode(offset);
   }
   {
-    TimingLogger::ScopedTiming split("InitOatCodeDexFiles", timings);
+    TimingLogger::ScopedTiming split("InitOatCodeDexFiles", timings_);
     offset = InitOatCodeDexFiles(offset);
   }
   size_ = offset;
@@ -255,7 +477,7 @@
     size_t bss_start = RoundUp(size_, kPageSize);
     size_t pointer_size = GetInstructionSetPointerSize(instruction_set);
     bss_size_ = 0u;
-    for (const DexFile* dex_file : dex_files) {
+    for (const DexFile* dex_file : *dex_files_) {
       dex_cache_arrays_offsets_.Put(dex_file, bss_start + bss_size_);
       DexCacheArraysLayout layout(pointer_size, dex_file);
       bss_size_ += layout.Size();
@@ -265,9 +487,10 @@
   CHECK_EQ(dex_files_->size(), oat_dex_files_.size());
   if (compiling_boot_image_) {
     CHECK_EQ(image_writer_ != nullptr,
-             key_value_store_->find(OatHeader::kImageLocationKey) == key_value_store_->end());
+             oat_header_->GetStoreValueByKey(OatHeader::kImageLocationKey) == nullptr);
   }
-  CHECK_ALIGNED(image_patch_delta_, kPageSize);
+
+  write_state_ = WriteState::kWriteRoData;
 }
 
 OatWriter::~OatWriter() {
@@ -1134,59 +1357,26 @@
   return true;
 }
 
-size_t OatWriter::InitOatHeader() {
-  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_);
-
+size_t OatWriter::InitOatHeader(InstructionSet instruction_set,
+                                const InstructionSetFeatures* instruction_set_features,
+                                uint32_t num_dex_files,
+                                SafeMap<std::string, std::string>* key_value_store) {
+  TimingLogger::ScopedTiming split("InitOatHeader", timings_);
+  oat_header_.reset(OatHeader::Create(instruction_set,
+                                      instruction_set_features,
+                                      num_dex_files,
+                                      key_value_store));
+  size_oat_header_ += sizeof(OatHeader);
+  size_oat_header_key_value_store_ += oat_header_->GetHeaderSize() - sizeof(OatHeader);
   return oat_header_->GetHeaderSize();
 }
 
 size_t OatWriter::InitOatDexFiles(size_t offset) {
-  // create the OatDexFiles
-  for (size_t i = 0; i != dex_files_->size(); ++i) {
-    const DexFile* dex_file = (*dex_files_)[i];
-    CHECK(dex_file != nullptr);
-    oat_dex_files_.emplace_back(offset, *dex_file);
-    offset += oat_dex_files_.back().SizeOf();
-  }
-  return offset;
-}
-
-size_t OatWriter::InitDexFiles(size_t offset) {
-  // calculate the offsets within OatDexFiles to the DexFiles
-  for (size_t i = 0; i != dex_files_->size(); ++i) {
-    // dex files are required to be 4 byte aligned
-    size_t original_offset = offset;
-    offset = RoundUp(offset, 4);
-    size_dex_file_alignment_ += offset - original_offset;
-
-    // set offset in OatDexFile to DexFile
-    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();
-
-    offset += dex_file->GetHeader().file_size_;
-  }
-  return offset;
-}
-
-size_t OatWriter::InitLookupTables(size_t offset) {
+  TimingLogger::ScopedTiming split("InitOatDexFiles", timings_);
+  // Initialize offsets of dex files.
   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;
-      size_oat_lookup_table_alignment_ += aligned_offset - offset;
-      offset = aligned_offset + oat_dex_file.lookup_table_->RawDataLength();
-    } else {
-      oat_dex_file.lookup_table_offset_ = 0;
-    }
+    oat_dex_file.offset_ = offset;
+    offset += oat_dex_file.SizeOf();
   }
   return offset;
 }
@@ -1239,7 +1429,6 @@
   oat_header_->SetExecutableOffset(offset);
   size_executable_offset_alignment_ = offset - old_offset;
   if (compiler_driver_->IsBootImage()) {
-    CHECK_EQ(image_patch_delta_, 0);
     InstructionSet instruction_set = compiler_driver_->GetInstructionSet();
 
     #define DO_TRAMPOLINE(field, fn_name) \
@@ -1264,7 +1453,6 @@
     oat_header_->SetQuickImtConflictTrampolineOffset(0);
     oat_header_->SetQuickResolutionTrampolineOffset(0);
     oat_header_->SetQuickToInterpreterBridgeOffset(0);
-    oat_header_->SetImagePatchDelta(image_patch_delta_);
   }
   return offset;
 }
@@ -1289,22 +1477,15 @@
 }
 
 bool OatWriter::WriteRodata(OutputStream* out) {
-  if (!GetOatDataOffset(out)) {
+  CHECK(write_state_ == WriteState::kWriteRoData);
+
+  if (!WriteClassOffsets(out)) {
+    LOG(ERROR) << "Failed to write class offsets to " << out->GetLocation();
     return false;
   }
-  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) == static_cast<off_t>(-1)) {
-    PLOG(ERROR) << "Failed to reserve space for oat header in " << out->GetLocation();
-    return false;
-  }
-  size_oat_header_ += sizeof(OatHeader);
-  size_oat_header_key_value_store_ += oat_header_->GetHeaderSize() - sizeof(OatHeader);
-
-  if (!WriteTables(out, file_offset)) {
-    LOG(ERROR) << "Failed to write oat tables to " << out->GetLocation();
+  if (!WriteClasses(out)) {
+    LOG(ERROR) << "Failed to write classes to " << out->GetLocation();
     return false;
   }
 
@@ -1313,6 +1494,7 @@
     LOG(ERROR) << "Failed to seek to oat code position in " << out->GetLocation();
     return false;
   }
+  size_t file_offset = oat_data_offset_;
   size_t relative_offset = static_cast<size_t>(tables_end_offset) - file_offset;
   relative_offset = WriteMaps(out, file_offset, relative_offset);
   if (relative_offset == 0) {
@@ -1332,11 +1514,13 @@
   }
   DCHECK_OFFSET();
 
+  write_state_ = WriteState::kWriteText;
   return true;
 }
 
 bool OatWriter::WriteCode(OutputStream* out) {
-  size_t header_size = oat_header_->GetHeaderSize();
+  CHECK(write_state_ == WriteState::kWriteText);
+
   const size_t file_offset = oat_data_offset_;
   size_t relative_offset = oat_header_->GetExecutableOffset();
   DCHECK_OFFSET();
@@ -1390,10 +1574,12 @@
     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_class_offsets_offset_);
     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_offsets_alignment_);
+    DO_STAT(size_oat_class_offsets_);
     DO_STAT(size_oat_class_type_);
     DO_STAT(size_oat_class_status_);
     DO_STAT(size_oat_class_method_bitmaps_);
@@ -1408,88 +1594,90 @@
   CHECK_EQ(file_offset + size_, static_cast<size_t>(oat_end_file_offset));
   CHECK_EQ(size_, relative_offset);
 
-  // Finalize the header checksum.
+  write_state_ = WriteState::kWriteHeader;
+  return true;
+}
+
+bool OatWriter::WriteHeader(OutputStream* out,
+                            uint32_t image_file_location_oat_checksum,
+                            uintptr_t image_file_location_oat_begin,
+                            int32_t image_patch_delta) {
+  CHECK(write_state_ == WriteState::kWriteHeader);
+
+  oat_header_->SetImageFileLocationOatChecksum(image_file_location_oat_checksum);
+  oat_header_->SetImageFileLocationOatDataBegin(image_file_location_oat_begin);
+  if (compiler_driver_->IsBootImage()) {
+    CHECK_EQ(image_patch_delta, 0);
+    CHECK_EQ(oat_header_->GetImagePatchDelta(), 0);
+  } else {
+    CHECK_ALIGNED(image_patch_delta, kPageSize);
+    oat_header_->SetImagePatchDelta(image_patch_delta);
+  }
   oat_header_->UpdateChecksumWithHeaderData();
 
-  // Write the header now that the checksum is final.
+  const size_t file_offset = oat_data_offset_;
+
+  off_t current_offset = out->Seek(0, kSeekCurrent);
+  if (current_offset == static_cast<off_t>(-1)) {
+    PLOG(ERROR) << "Failed to get current offset from " << out->GetLocation();
+    return false;
+  }
   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)));
+
+  // Flush all other data before writing the header.
+  if (!out->Flush()) {
+    PLOG(ERROR) << "Failed to flush before writing oat header to " << out->GetLocation();
+    return false;
+  }
+  // Write the header.
+  size_t header_size = oat_header_->GetHeaderSize();
   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) == static_cast<off_t>(-1)) {
-    PLOG(ERROR) << "Failed to seek to end after writing oat header to " << out->GetLocation();
+  // Flush the header data.
+  if (!out->Flush()) {
+    PLOG(ERROR) << "Failed to flush after writing oat header to " << out->GetLocation();
     return false;
   }
-  DCHECK_EQ(oat_end_file_offset, out->Seek(0, kSeekCurrent));
 
+  if (out->Seek(current_offset, kSeekSet) == static_cast<off_t>(-1)) {
+    PLOG(ERROR) << "Failed to seek back after writing oat header to " << out->GetLocation();
+    return false;
+  }
+  DCHECK_EQ(current_offset, out->Seek(0, kSeekCurrent));
+
+  write_state_ = WriteState::kDone;
   return true;
 }
 
-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)) {
-      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_;
-    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];
-      PLOG(ERROR) << "Failed to seek to dex file section. Actual: " << actual_offset
-                  << " Expected: " << expected_offset << " File: " << dex_file->GetLocation();
-      return false;
-    }
-    const DexFile* dex_file = (*dex_files_)[i];
-    if (!out->WriteFully(&dex_file->GetHeader(), dex_file->GetHeader().file_size_)) {
-      PLOG(ERROR) << "Failed to write dex file " << dex_file->GetLocation()
-                  << " to " << out->GetLocation();
-      return false;
-    }
-    size_dex_file_ += dex_file->GetHeader().file_size_;
-  }
-  if (!WriteLookupTables(out, file_offset)) {
-    return false;
-  }
-  for (size_t i = 0; i != oat_classes_.size(); ++i) {
-    if (!oat_classes_[i].Write(this, out, file_offset)) {
-      PLOG(ERROR) << "Failed to write oat methods information to " << out->GetLocation();
-      return false;
-    }
-  }
-  return true;
-}
-
-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_;
-    DCHECK_EQ(lookup_table_offset == 0, table == nullptr);
-    if (lookup_table_offset == 0) {
-      continue;
-    }
-    const uint32_t expected_offset = file_offset + lookup_table_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];
-      PLOG(ERROR) << "Failed to seek to lookup table section. Actual: " << actual_offset
-                  << " Expected: " << expected_offset << " File: " << dex_file->GetLocation();
-      return false;
-    }
-    if (table != nullptr) {
-      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();
+bool OatWriter::WriteClassOffsets(OutputStream* out) {
+  for (OatDexFile& oat_dex_file : oat_dex_files_) {
+    if (oat_dex_file.class_offsets_offset_ != 0u) {
+      uint32_t expected_offset = oat_data_offset_ + oat_dex_file.class_offsets_offset_;
+      off_t actual_offset = out->Seek(expected_offset, kSeekSet);
+      if (static_cast<uint32_t>(actual_offset) != expected_offset) {
+        PLOG(ERROR) << "Failed to seek to oat class offsets section. Actual: " << actual_offset
+                    << " Expected: " << expected_offset << " File: " << oat_dex_file.GetLocation();
         return false;
       }
-      size_oat_lookup_table_ += table->RawDataLength();
+      if (!oat_dex_file.WriteClassOffsets(this, out)) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+bool OatWriter::WriteClasses(OutputStream* out) {
+  for (OatClass& oat_class : oat_classes_) {
+    if (!oat_class.Write(this, out, oat_data_offset_)) {
+      PLOG(ERROR) << "Failed to write oat methods information to " << out->GetLocation();
+      return false;
     }
   }
   return true;
@@ -1585,6 +1773,455 @@
   return true;
 }
 
+bool OatWriter::ReadDexFileHeader(File* file, OatDexFile* oat_dex_file) {
+  // Read the dex file header and perform minimal verification.
+  uint8_t raw_header[sizeof(DexFile::Header)];
+  if (!file->ReadFully(&raw_header, sizeof(DexFile::Header))) {
+    PLOG(ERROR) << "Failed to read dex file header. Actual: "
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  if (!ValidateDexFileHeader(raw_header, oat_dex_file->GetLocation())) {
+    return false;
+  }
+
+  const UnalignedDexFileHeader* header = AsUnalignedDexFileHeader(raw_header);
+  oat_dex_file->dex_file_size_ = header->file_size_;
+  oat_dex_file->dex_file_location_checksum_ = header->checksum_;
+  oat_dex_file->class_offsets_.resize(header->class_defs_size_);
+  return true;
+}
+
+bool OatWriter::ValidateDexFileHeader(const uint8_t* raw_header, const char* location) {
+  if (!DexFile::IsMagicValid(raw_header)) {
+    LOG(ERROR) << "Invalid magic number in dex file header. " << " File: " << location;
+    return false;
+  }
+  if (!DexFile::IsVersionValid(raw_header)) {
+    LOG(ERROR) << "Invalid version number in dex file header. " << " File: " << location;
+    return false;
+  }
+  const UnalignedDexFileHeader* header = AsUnalignedDexFileHeader(raw_header);
+  if (header->file_size_ < sizeof(DexFile::Header)) {
+    LOG(ERROR) << "Dex file header specifies file size insufficient to contain the header."
+               << " File: " << location;
+    return false;
+  }
+  return true;
+}
+
+bool OatWriter::WriteDexFiles(OutputStream* rodata, File* file) {
+  TimingLogger::ScopedTiming split("WriteDexFiles", timings_);
+
+  // Get the elf file offset of the oat file.
+  if (!GetOatDataOffset(rodata)) {
+    return false;
+  }
+
+  // Write dex files.
+  for (OatDexFile& oat_dex_file : oat_dex_files_) {
+    if (!WriteDexFile(rodata, file, &oat_dex_file)) {
+      return false;
+    }
+  }
+
+  // Close sources.
+  for (OatDexFile& oat_dex_file : oat_dex_files_) {
+    oat_dex_file.source_.Clear();  // Get rid of the reference, it's about to be invalidated.
+  }
+  zipped_dex_files_.clear();
+  zip_archives_.clear();
+  raw_dex_files_.clear();
+  return true;
+}
+
+bool OatWriter::WriteDexFile(OutputStream* rodata, File* file, OatDexFile* oat_dex_file) {
+  if (!SeekToDexFile(rodata, file, oat_dex_file)) {
+    return false;
+  }
+  if (oat_dex_file->source_.IsZipEntry()) {
+    if (!WriteDexFile(rodata, file, oat_dex_file, oat_dex_file->source_.GetZipEntry())) {
+      return false;
+    }
+  } else if (oat_dex_file->source_.IsRawFile()) {
+    if (!WriteDexFile(rodata, file, oat_dex_file, oat_dex_file->source_.GetRawFile())) {
+      return false;
+    }
+  } else {
+    DCHECK(oat_dex_file->source_.IsRawData());
+    if (!WriteDexFile(rodata, oat_dex_file, oat_dex_file->source_.GetRawData())) {
+      return false;
+    }
+  }
+
+  // Update current size and account for the written data.
+  DCHECK_EQ(size_, oat_dex_file->dex_file_offset_);
+  size_ += oat_dex_file->dex_file_size_;
+  size_dex_file_ += oat_dex_file->dex_file_size_;
+  return true;
+}
+
+bool OatWriter::SeekToDexFile(OutputStream* out, File* file, OatDexFile* oat_dex_file) {
+  // Dex files are required to be 4 byte aligned.
+  size_t original_offset = size_;
+  size_t offset = RoundUp(original_offset, 4);
+  size_dex_file_alignment_ += offset - original_offset;
+
+  // Seek to the start of the dex file and flush any pending operations in the stream.
+  // Verify that, after flushing the stream, the file is at the same offset as the stream.
+  uint32_t start_offset = oat_data_offset_ + offset;
+  off_t actual_offset = out->Seek(start_offset, kSeekSet);
+  if (actual_offset != static_cast<off_t>(start_offset)) {
+    PLOG(ERROR) << "Failed to seek to dex file section. Actual: " << actual_offset
+                << " Expected: " << start_offset
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  if (!out->Flush()) {
+    PLOG(ERROR) << "Failed to flush before writing dex file."
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  actual_offset = lseek(file->Fd(), 0, SEEK_CUR);
+  if (actual_offset != static_cast<off_t>(start_offset)) {
+    PLOG(ERROR) << "Stream/file position mismatch! Actual: " << actual_offset
+                << " Expected: " << start_offset
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+
+  size_ = offset;
+  oat_dex_file->dex_file_offset_ = offset;
+  return true;
+}
+
+bool OatWriter::WriteDexFile(OutputStream* rodata,
+                             File* file,
+                             OatDexFile* oat_dex_file,
+                             ZipEntry* dex_file) {
+  size_t start_offset = oat_data_offset_ + size_;
+  DCHECK_EQ(static_cast<off_t>(start_offset), rodata->Seek(0, kSeekCurrent));
+
+  // Extract the dex file and get the extracted size.
+  std::string error_msg;
+  if (!dex_file->ExtractToFile(*file, &error_msg)) {
+    LOG(ERROR) << "Failed to extract dex file from ZIP entry: " << error_msg
+               << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  if (file->Flush() != 0) {
+    PLOG(ERROR) << "Failed to flush dex file from ZIP entry."
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  off_t extracted_end = lseek(file->Fd(), 0, SEEK_CUR);
+  if (extracted_end == static_cast<off_t>(-1)) {
+    PLOG(ERROR) << "Failed get end offset after writing dex file from ZIP entry."
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  if (extracted_end < static_cast<off_t>(start_offset)) {
+    LOG(ERROR) << "Dex file end position is before start position! End: " << extracted_end
+               << " Start: " << start_offset
+               << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  uint64_t extracted_size = static_cast<uint64_t>(extracted_end - start_offset);
+  if (extracted_size < sizeof(DexFile::Header)) {
+    LOG(ERROR) << "Extracted dex file is shorter than dex file header. size: "
+               << extracted_size << " File: " << oat_dex_file->GetLocation();
+    return false;
+  }
+
+  // Read the dex file header and extract required data to OatDexFile.
+  off_t actual_offset = lseek(file->Fd(), start_offset, SEEK_SET);
+  if (actual_offset != static_cast<off_t>(start_offset)) {
+    PLOG(ERROR) << "Failed to seek back to dex file header. Actual: " << actual_offset
+                << " Expected: " << start_offset
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  if (!ReadDexFileHeader(file, oat_dex_file)) {
+    return false;
+  }
+  if (extracted_size < oat_dex_file->dex_file_size_) {
+    LOG(ERROR) << "Extracted truncated dex file. Extracted size: " << extracted_size
+               << " file size from header: " << oat_dex_file->dex_file_size_
+               << " File: " << oat_dex_file->GetLocation();
+    return false;
+  }
+
+  // Override the checksum from header with the CRC from ZIP entry.
+  oat_dex_file->dex_file_location_checksum_ = dex_file->GetCrc32();
+
+  // Seek both file and stream to the end offset.
+  size_t end_offset = start_offset + oat_dex_file->dex_file_size_;
+  actual_offset = lseek(file->Fd(), end_offset, SEEK_SET);
+  if (actual_offset != static_cast<off_t>(end_offset)) {
+    PLOG(ERROR) << "Failed to seek to end of dex file. Actual: " << actual_offset
+                << " Expected: " << end_offset
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  actual_offset = rodata->Seek(end_offset, kSeekSet);
+  if (actual_offset != static_cast<off_t>(end_offset)) {
+    PLOG(ERROR) << "Failed to seek stream to end of dex file. Actual: " << actual_offset
+                << " Expected: " << end_offset << " File: " << oat_dex_file->GetLocation();
+    return false;
+  }
+  if (!rodata->Flush()) {
+    PLOG(ERROR) << "Failed to flush stream after seeking over dex file."
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+
+  // If we extracted more than the size specified in the header, truncate the file.
+  if (extracted_size > oat_dex_file->dex_file_size_) {
+    if (file->SetLength(end_offset) != 0) {
+      PLOG(ERROR) << "Failed to truncate excessive dex file length."
+                  << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+      return false;
+    }
+  }
+
+  return true;
+}
+
+bool OatWriter::WriteDexFile(OutputStream* rodata,
+                             File* file,
+                             OatDexFile* oat_dex_file,
+                             File* dex_file) {
+  size_t start_offset = oat_data_offset_ + size_;
+  DCHECK_EQ(static_cast<off_t>(start_offset), rodata->Seek(0, kSeekCurrent));
+
+  off_t input_offset = lseek(dex_file->Fd(), 0, SEEK_SET);
+  if (input_offset != static_cast<off_t>(0)) {
+    PLOG(ERROR) << "Failed to seek to dex file header. Actual: " << input_offset
+                << " Expected: 0"
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  if (!ReadDexFileHeader(dex_file, oat_dex_file)) {
+    return false;
+  }
+
+  // Copy the input dex file using sendfile().
+  if (!file->Copy(dex_file, 0, oat_dex_file->dex_file_size_)) {
+    PLOG(ERROR) << "Failed to copy dex file to oat file."
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  if (file->Flush() != 0) {
+    PLOG(ERROR) << "Failed to flush dex file."
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+
+  // Check file position and seek the stream to the end offset.
+  size_t end_offset = start_offset + oat_dex_file->dex_file_size_;
+  off_t actual_offset = lseek(file->Fd(), 0, SEEK_CUR);
+  if (actual_offset != static_cast<off_t>(end_offset)) {
+    PLOG(ERROR) << "Unexpected file position after copying dex file. Actual: " << actual_offset
+                << " Expected: " << end_offset
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+  actual_offset = rodata->Seek(end_offset, kSeekSet);
+  if (actual_offset != static_cast<off_t>(end_offset)) {
+    PLOG(ERROR) << "Failed to seek stream to end of dex file. Actual: " << actual_offset
+                << " Expected: " << end_offset << " File: " << oat_dex_file->GetLocation();
+    return false;
+  }
+  if (!rodata->Flush()) {
+    PLOG(ERROR) << "Failed to flush stream after seeking over dex file."
+                << " File: " << oat_dex_file->GetLocation() << " Output: " << file->GetPath();
+    return false;
+  }
+
+  return true;
+}
+
+bool OatWriter::WriteDexFile(OutputStream* rodata,
+                             OatDexFile* oat_dex_file,
+                             const uint8_t* dex_file) {
+  // Note: The raw data has already been checked to contain the header
+  // and all the data that the header specifies as the file size.
+  DCHECK(dex_file != nullptr);
+  DCHECK(ValidateDexFileHeader(dex_file, oat_dex_file->GetLocation()));
+  const UnalignedDexFileHeader* header = AsUnalignedDexFileHeader(dex_file);
+
+  if (!rodata->WriteFully(dex_file, header->file_size_)) {
+    PLOG(ERROR) << "Failed to write dex file " << oat_dex_file->GetLocation()
+                << " to " << rodata->GetLocation();
+    return false;
+  }
+  if (!rodata->Flush()) {
+    PLOG(ERROR) << "Failed to flush stream after writing dex file."
+                << " File: " << oat_dex_file->GetLocation();
+    return false;
+  }
+
+  // Update dex file size and resize class offsets in the OatDexFile.
+  // Note: For raw data, the checksum is passed directly to AddRawDexFileSource().
+  oat_dex_file->dex_file_size_ = header->file_size_;
+  oat_dex_file->class_offsets_.resize(header->class_defs_size_);
+  return true;
+}
+
+bool OatWriter::WriteOatDexFiles(OutputStream* rodata) {
+  TimingLogger::ScopedTiming split("WriteOatDexFiles", timings_);
+
+  // Seek to the start of OatDexFiles, i.e. to the end of the OatHeader.  If there are
+  // no OatDexFiles, no data is actually written to .rodata before WriteHeader() and
+  // this Seek() ensures that we reserve the space for OatHeader in .rodata.
+  DCHECK(oat_dex_files_.empty() || oat_dex_files_[0u].offset_ == oat_header_->GetHeaderSize());
+  uint32_t expected_offset = oat_data_offset_ + oat_header_->GetHeaderSize();
+  off_t actual_offset = rodata->Seek(expected_offset, kSeekSet);
+  if (static_cast<uint32_t>(actual_offset) != expected_offset) {
+    PLOG(ERROR) << "Failed to seek to OatDexFile table section. Actual: " << actual_offset
+                << " Expected: " << expected_offset << " File: " << rodata->GetLocation();
+    return false;
+  }
+
+  for (size_t i = 0, size = oat_dex_files_.size(); i != size; ++i) {
+    OatDexFile* oat_dex_file = &oat_dex_files_[i];
+
+    DCHECK_EQ(oat_data_offset_ + oat_dex_file->offset_,
+              static_cast<size_t>(rodata->Seek(0, kSeekCurrent)));
+
+    // Write OatDexFile.
+    if (!oat_dex_file->Write(this, rodata)) {
+      PLOG(ERROR) << "Failed to write oat dex information to " << rodata->GetLocation();
+      return false;
+    }
+  }
+
+  return true;
+}
+
+bool OatWriter::ExtendForTypeLookupTables(OutputStream* rodata, File* file, size_t offset) {
+  TimingLogger::ScopedTiming split("ExtendForTypeLookupTables", timings_);
+
+  int64_t new_length = oat_data_offset_ + dchecked_integral_cast<int64_t>(offset);
+  if (file->SetLength(new_length) != 0) {
+    PLOG(ERROR) << "Failed to extend file for type lookup tables. new_length: " << new_length
+        << "File: " << file->GetPath();
+    return false;
+  }
+  off_t actual_offset = rodata->Seek(new_length, kSeekSet);
+  if (actual_offset != static_cast<off_t>(new_length)) {
+    PLOG(ERROR) << "Failed to seek stream after extending file for type lookup tables."
+                << " Actual: " << actual_offset << " Expected: " << new_length
+                << " File: " << rodata->GetLocation();
+    return false;
+  }
+  if (!rodata->Flush()) {
+    PLOG(ERROR) << "Failed to flush stream after extending for type lookup tables."
+                << " File: " << rodata->GetLocation();
+    return false;
+  }
+  return true;
+}
+
+bool OatWriter::OpenDexFiles(
+    File* file,
+    /*out*/ std::unique_ptr<MemMap>* opened_dex_files_map,
+    /*out*/ std::vector<std::unique_ptr<const DexFile>>* opened_dex_files) {
+  TimingLogger::ScopedTiming split("OpenDexFiles", timings_);
+
+  if (oat_dex_files_.empty()) {
+    // Nothing to do.
+    return true;
+  }
+
+  size_t map_offset = oat_dex_files_[0].dex_file_offset_;
+  size_t length = size_ - map_offset;
+  std::string error_msg;
+  std::unique_ptr<MemMap> dex_files_map(MemMap::MapFile(length,
+                                                        PROT_READ | PROT_WRITE,
+                                                        MAP_SHARED,
+                                                        file->Fd(),
+                                                        oat_data_offset_ + map_offset,
+                                                        /* low_4gb */ false,
+                                                        file->GetPath().c_str(),
+                                                        &error_msg));
+  if (dex_files_map == nullptr) {
+    LOG(ERROR) << "Failed to mmap() dex files from oat file. File: " << file->GetPath()
+               << " error: " << error_msg;
+    return false;
+  }
+  std::vector<std::unique_ptr<const DexFile>> dex_files;
+  for (OatDexFile& oat_dex_file : oat_dex_files_) {
+    // Make sure no one messed with input files while we were copying data.
+    // At the very least we need consistent file size and number of class definitions.
+    const uint8_t* raw_dex_file =
+        dex_files_map->Begin() + oat_dex_file.dex_file_offset_ - map_offset;
+    if (!ValidateDexFileHeader(raw_dex_file, oat_dex_file.GetLocation())) {
+      // Note: ValidateDexFileHeader() already logged an error message.
+      LOG(ERROR) << "Failed to verify written dex file header!"
+          << " Output: " << file->GetPath() << " ~ " << std::hex << map_offset
+          << " ~ " << static_cast<const void*>(raw_dex_file);
+      return false;
+    }
+    const UnalignedDexFileHeader* header = AsUnalignedDexFileHeader(raw_dex_file);
+    if (header->file_size_ != oat_dex_file.dex_file_size_) {
+      LOG(ERROR) << "File size mismatch in written dex file header! Expected: "
+          << oat_dex_file.dex_file_size_ << " Actual: " << header->file_size_
+          << " Output: " << file->GetPath();
+      return false;
+    }
+    if (header->class_defs_size_ != oat_dex_file.class_offsets_.size()) {
+      LOG(ERROR) << "Class defs size mismatch in written dex file header! Expected: "
+          << oat_dex_file.class_offsets_.size() << " Actual: " << header->class_defs_size_
+          << " Output: " << file->GetPath();
+      return false;
+    }
+
+    // Now, open the dex file.
+    dex_files.emplace_back(DexFile::Open(raw_dex_file,
+                                         oat_dex_file.dex_file_size_,
+                                         oat_dex_file.GetLocation(),
+                                         oat_dex_file.dex_file_location_checksum_,
+                                         /* oat_dex_file */ nullptr,
+                                         &error_msg));
+    if (dex_files.back() == nullptr) {
+      LOG(ERROR) << "Failed to open dex file from oat file. File:" << oat_dex_file.GetLocation();
+      return false;
+    }
+  }
+
+  *opened_dex_files_map = std::move(dex_files_map);
+  *opened_dex_files = std::move(dex_files);
+  return true;
+}
+
+bool OatWriter::WriteTypeLookupTables(
+    MemMap* opened_dex_files_map,
+    const std::vector<std::unique_ptr<const DexFile>>& opened_dex_files) {
+  TimingLogger::ScopedTiming split("WriteTypeLookupTables", timings_);
+
+  DCHECK_EQ(opened_dex_files.size(), oat_dex_files_.size());
+  for (size_t i = 0, size = opened_dex_files.size(); i != size; ++i) {
+    OatDexFile* oat_dex_file = &oat_dex_files_[i];
+    if (oat_dex_file->lookup_table_offset_ != 0u) {
+      DCHECK(oat_dex_file->create_type_lookup_table_ == CreateTypeLookupTable::kCreate);
+      DCHECK_NE(oat_dex_file->class_offsets_.size(), 0u);
+      size_t map_offset = oat_dex_files_[0].dex_file_offset_;
+      size_t lookup_table_offset = oat_dex_file->lookup_table_offset_;
+      uint8_t* lookup_table = opened_dex_files_map->Begin() + (lookup_table_offset - map_offset);
+      opened_dex_files[i]->CreateTypeLookupTable(lookup_table);
+    }
+  }
+
+  DCHECK_EQ(opened_dex_files_map == nullptr, opened_dex_files.empty());
+  if (opened_dex_files_map != nullptr && !opened_dex_files_map->Sync()) {
+    PLOG(ERROR) << "Failed to Sync() type lookup tables. Map: " << opened_dex_files_map->GetName();
+    return false;
+  }
+
+  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
@@ -1611,15 +2248,20 @@
   }
 }
 
-OatWriter::OatDexFile::OatDexFile(size_t offset, const DexFile& dex_file) {
-  offset_ = offset;
-  const std::string& location(dex_file.GetLocation());
-  dex_file_location_size_ = location.size();
-  dex_file_location_data_ = reinterpret_cast<const uint8_t*>(location.data());
-  dex_file_location_checksum_ = dex_file.GetLocationChecksum();
-  dex_file_offset_ = 0;
-  lookup_table_offset_ = 0;
-  class_offsets_.resize(dex_file.NumClassDefs());
+OatWriter::OatDexFile::OatDexFile(const char* dex_file_location,
+                                  DexFileSource source,
+                                  CreateTypeLookupTable create_type_lookup_table)
+    : source_(source),
+      create_type_lookup_table_(create_type_lookup_table),
+      dex_file_size_(0),
+      offset_(0),
+      dex_file_location_size_(strlen(dex_file_location)),
+      dex_file_location_data_(dex_file_location),
+      dex_file_location_checksum_(0u),
+      dex_file_offset_(0u),
+      class_offsets_offset_(0u),
+      lookup_table_offset_(0u),
+      class_offsets_() {
 }
 
 size_t OatWriter::OatDexFile::SizeOf() const {
@@ -1627,24 +2269,54 @@
           + dex_file_location_size_
           + sizeof(dex_file_location_checksum_)
           + sizeof(dex_file_offset_)
-          + sizeof(lookup_table_offset_)
-          + (sizeof(class_offsets_[0]) * class_offsets_.size());
+          + sizeof(class_offsets_offset_)
+          + sizeof(lookup_table_offset_);
 }
 
-bool OatWriter::OatDexFile::Write(OatWriter* oat_writer,
-                                  OutputStream* out,
-                                  const size_t file_offset) const {
+void OatWriter::OatDexFile::ReserveTypeLookupTable(OatWriter* oat_writer) {
+  DCHECK_EQ(lookup_table_offset_, 0u);
+  if (create_type_lookup_table_ == CreateTypeLookupTable::kCreate && !class_offsets_.empty()) {
+    size_t table_size = TypeLookupTable::RawDataLength(class_offsets_.size());
+    if (table_size != 0u) {
+      // Type tables are required to be 4 byte aligned.
+      size_t original_offset = oat_writer->size_;
+      size_t offset = RoundUp(original_offset, 4);
+      oat_writer->size_oat_lookup_table_alignment_ += offset - original_offset;
+      lookup_table_offset_ = offset;
+      oat_writer->size_ = offset + table_size;
+      oat_writer->size_oat_lookup_table_ += table_size;
+    }
+  }
+}
+
+void OatWriter::OatDexFile::ReserveClassOffsets(OatWriter* oat_writer) {
+  DCHECK_EQ(class_offsets_offset_, 0u);
+  if (!class_offsets_.empty()) {
+    // Class offsets are required to be 4 byte aligned.
+    size_t original_offset = oat_writer->size_;
+    size_t offset = RoundUp(original_offset, 4);
+    oat_writer->size_oat_class_offsets_alignment_ += offset - original_offset;
+    class_offsets_offset_ = offset;
+    oat_writer->size_ = offset + GetClassOffsetsRawSize();
+  }
+}
+
+bool OatWriter::OatDexFile::Write(OatWriter* oat_writer, OutputStream* out) const {
+  const size_t file_offset = oat_writer->oat_data_offset_;
   DCHECK_OFFSET_();
+
   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 (!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 (!oat_writer->WriteData(out,
                              &dex_file_location_checksum_,
                              sizeof(dex_file_location_checksum_))) {
@@ -1652,21 +2324,35 @@
     return false;
   }
   oat_writer->size_oat_dex_file_location_checksum_ += sizeof(dex_file_location_checksum_);
+
   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 (!oat_writer->WriteData(out, &class_offsets_offset_, sizeof(class_offsets_offset_))) {
+    PLOG(ERROR) << "Failed to write class offsets offset to " << out->GetLocation();
+    return false;
+  }
+  oat_writer->size_oat_dex_file_class_offsets_offset_ += sizeof(class_offsets_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_dex_file_lookup_table_offset_ += sizeof(lookup_table_offset_);
+
+  return true;
+}
+
+bool OatWriter::OatDexFile::WriteClassOffsets(OatWriter* oat_writer, OutputStream* out) {
   if (!oat_writer->WriteData(out, class_offsets_.data(), GetClassOffsetsRawSize())) {
-    PLOG(ERROR) << "Failed to write methods offsets to " << out->GetLocation();
+    PLOG(ERROR) << "Failed to write oat class offsets for " << GetLocation()
+                << " to " << out->GetLocation();
     return false;
   }
-  oat_writer->size_oat_dex_file_class_offsets_ += GetClassOffsetsRawSize();
+  oat_writer->size_oat_class_offsets_ += GetClassOffsetsRawSize();
   return true;
 }
 
diff --git a/compiler/oat_writer.h b/compiler/oat_writer.h
index 5feb5fc..d681998 100644
--- a/compiler/oat_writer.h
+++ b/compiler/oat_writer.h
@@ -27,7 +27,9 @@
 #include "method_reference.h"
 #include "mirror/class.h"
 #include "oat.h"
+#include "os.h"
 #include "safe_map.h"
+#include "ScopedFd.h"
 #include "utils/array_ref.h"
 
 namespace art {
@@ -39,6 +41,7 @@
 class OutputStream;
 class TimingLogger;
 class TypeLookupTable;
+class ZipEntry;
 
 namespace dwarf {
 struct MethodDebugInfo;
@@ -61,6 +64,11 @@
 // ...
 // TypeLookupTable[D]
 //
+// ClassOffsets[0]   one table of OatClass offsets for each class def for each OatDexFile.
+// ClassOffsets[1]
+// ...
+// ClassOffsets[D]
+//
 // OatClass[0]       one variable sized OatClass for each of C DexFile::ClassDefs
 // OatClass[1]       contains OatClass entries with class status, offsets to code, etc.
 // ...
@@ -93,15 +101,65 @@
 //
 class OatWriter {
  public:
-  OatWriter(const std::vector<const DexFile*>& dex_files,
-            uint32_t image_file_location_oat_checksum,
-            uintptr_t image_file_location_oat_begin,
-            int32_t image_patch_delta,
-            const CompilerDriver* compiler,
-            ImageWriter* image_writer,
-            bool compiling_boot_image,
-            TimingLogger* timings,
-            SafeMap<std::string, std::string>* key_value_store);
+  enum class CreateTypeLookupTable {
+    kCreate,
+    kDontCreate,
+    kDefault = kCreate
+  };
+
+  OatWriter(bool compiling_boot_image, TimingLogger* timings);
+
+  // To produce a valid oat file, the user must first add sources with any combination of
+  //   - AddDexFileSource(),
+  //   - AddZippedDexFilesSource(),
+  //   - AddRawDexFileSource().
+  // Then the user must call in order
+  //   - WriteAndOpenDexFiles()
+  //   - PrepareLayout(),
+  //   - WriteRodata(),
+  //   - WriteCode(),
+  //   - WriteHeader().
+
+  // Add dex file source(s) from a file, either a plain dex file or
+  // a zip file with one or more dex files.
+  bool AddDexFileSource(
+      const char* filename,
+      const char* location,
+      CreateTypeLookupTable create_type_lookup_table = CreateTypeLookupTable::kDefault);
+  // Add dex file source(s) from a zip file specified by a file handle.
+  bool AddZippedDexFilesSource(
+      ScopedFd&& zip_fd,
+      const char* location,
+      CreateTypeLookupTable create_type_lookup_table = CreateTypeLookupTable::kDefault);
+  // Add dex file source from raw memory.
+  bool AddRawDexFileSource(
+      const ArrayRef<const uint8_t>& data,
+      const char* location,
+      uint32_t location_checksum,
+      CreateTypeLookupTable create_type_lookup_table = CreateTypeLookupTable::kDefault);
+  dchecked_vector<const char*> GetSourceLocations() const;
+
+  // Write raw dex files to the .rodata section and open them from the oat file.
+  bool WriteAndOpenDexFiles(OutputStream* rodata,
+                            File* file,
+                            InstructionSet instruction_set,
+                            const InstructionSetFeatures* instruction_set_features,
+                            SafeMap<std::string, std::string>* key_value_store,
+                            /*out*/ std::unique_ptr<MemMap>* opened_dex_files_map,
+                            /*out*/ std::vector<std::unique_ptr<const DexFile>>* opened_dex_files);
+  // Prepare layout of remaining data.
+  void PrepareLayout(const CompilerDriver* compiler,
+                     ImageWriter* image_writer,
+                     const std::vector<const DexFile*>& dex_files);
+  // Write the rest of .rodata section (ClassOffsets[], OatClass[], maps).
+  bool WriteRodata(OutputStream* out);
+  // Write the code to the .text section.
+  bool WriteCode(OutputStream* out);
+  // Write the oat header. This finalizes the oat file.
+  bool WriteHeader(OutputStream* out,
+                   uint32_t image_file_location_oat_checksum,
+                   uintptr_t image_file_location_oat_begin,
+                   int32_t image_patch_delta);
 
   // Returns whether the oat file has an associated image.
   bool HasImage() const {
@@ -130,9 +188,6 @@
     return ArrayRef<const uintptr_t>(absolute_patch_locations_);
   }
 
-  bool WriteRodata(OutputStream* out);
-  bool WriteCode(OutputStream* out);
-
   ~OatWriter();
 
   ArrayRef<const dwarf::MethodDebugInfo> GetMethodDebugInfo() const {
@@ -144,6 +199,7 @@
   }
 
  private:
+  class DexFileSource;
   class OatClass;
   class OatDexFile;
 
@@ -174,29 +230,65 @@
   // with a given DexMethodVisitor.
   bool VisitDexMethods(DexMethodVisitor* visitor);
 
-  size_t InitOatHeader();
+  size_t InitOatHeader(InstructionSet instruction_set,
+                       const InstructionSetFeatures* instruction_set_features,
+                       uint32_t num_dex_files,
+                       SafeMap<std::string, std::string>* key_value_store);
   size_t InitOatDexFiles(size_t offset);
-  size_t InitLookupTables(size_t offset);
-  size_t InitDexFiles(size_t offset);
   size_t InitOatClasses(size_t offset);
   size_t InitOatMaps(size_t offset);
   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);
+  bool WriteClassOffsets(OutputStream* out);
+  bool WriteClasses(OutputStream* out);
   size_t WriteMaps(OutputStream* out, const size_t file_offset, size_t relative_offset);
   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 ReadDexFileHeader(File* file, OatDexFile* oat_dex_file);
+  bool ValidateDexFileHeader(const uint8_t* raw_header, const char* location);
+  bool WriteDexFiles(OutputStream* rodata, File* file);
+  bool WriteDexFile(OutputStream* rodata, File* file, OatDexFile* oat_dex_file);
+  bool SeekToDexFile(OutputStream* rodata, File* file, OatDexFile* oat_dex_file);
+  bool WriteDexFile(OutputStream* rodata, File* file, OatDexFile* oat_dex_file, ZipEntry* dex_file);
+  bool WriteDexFile(OutputStream* rodata, File* file, OatDexFile* oat_dex_file, File* dex_file);
+  bool WriteDexFile(OutputStream* rodata, OatDexFile* oat_dex_file, const uint8_t* dex_file);
+  bool WriteOatDexFiles(OutputStream* rodata);
+  bool ExtendForTypeLookupTables(OutputStream* rodata, File* file, size_t offset);
+  bool OpenDexFiles(File* file,
+                    /*out*/ std::unique_ptr<MemMap>* opened_dex_files_map,
+                    /*out*/ std::vector<std::unique_ptr<const DexFile>>* opened_dex_files);
+  bool WriteTypeLookupTables(MemMap* opened_dex_files_map,
+                             const std::vector<std::unique_ptr<const DexFile>>& opened_dex_files);
   bool WriteCodeAlignment(OutputStream* out, uint32_t aligned_code_delta);
   bool WriteData(OutputStream* out, const void* data, size_t size);
 
+  enum class WriteState {
+    kAddingDexFileSources,
+    kPrepareLayout,
+    kWriteRoData,
+    kWriteText,
+    kWriteHeader,
+    kDone
+  };
+
+  WriteState write_state_;
+  TimingLogger* timings_;
+
+  std::vector<std::unique_ptr<File>> raw_dex_files_;
+  std::vector<std::unique_ptr<ZipArchive>> zip_archives_;
+  std::vector<std::unique_ptr<ZipEntry>> zipped_dex_files_;
+
+  // Using std::list<> which doesn't move elements around on push/emplace_back().
+  // We need this because we keep plain pointers to the strings' c_str().
+  std::list<std::string> zipped_dex_file_locations_;
+
   dchecked_vector<dwarf::MethodDebugInfo> method_info_;
 
-  const CompilerDriver* const compiler_driver_;
-  ImageWriter* const image_writer_;
+  const CompilerDriver* compiler_driver_;
+  ImageWriter* image_writer_;
   const bool compiling_boot_image_;
 
   // note OatFile does not take ownership of the DexFiles
@@ -215,13 +307,7 @@
   // Offset of the oat data from the start of the mmapped region of the elf file.
   size_t oat_data_offset_;
 
-  // dependencies on the image.
-  uint32_t image_file_location_oat_checksum_;
-  uintptr_t image_file_location_oat_begin_;
-  int32_t image_patch_delta_;
-
   // data to write
-  SafeMap<std::string, std::string>* key_value_store_;
   std::unique_ptr<OatHeader> oat_header_;
   dchecked_vector<OatDexFile> oat_dex_files_;
   dchecked_vector<OatClass> oat_classes_;
@@ -257,10 +343,12 @@
   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_class_offsets_offset_;
   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_offsets_alignment_;
+  uint32_t size_oat_class_offsets_;
   uint32_t size_oat_class_type_;
   uint32_t size_oat_class_status_;
   uint32_t size_oat_class_method_bitmaps_;
@@ -269,7 +357,7 @@
   std::unique_ptr<linker::RelativePatcher> relative_patcher_;
 
   // The locations of absolute patches relative to the start of the executable section.
-  std::vector<uintptr_t> absolute_patch_locations_;
+  dchecked_vector<uintptr_t> absolute_patch_locations_;
 
   // Map method reference to assigned offset.
   // Wrap the map in a class implementing linker::RelativePatcherTargetProvider.
diff --git a/compiler/utils/test_dex_file_builder.h b/compiler/utils/test_dex_file_builder.h
index b6a228c..e57a540 100644
--- a/compiler/utils/test_dex_file_builder.h
+++ b/compiler/utils/test_dex_file_builder.h
@@ -21,6 +21,7 @@
 #include <set>
 #include <map>
 #include <vector>
+#include <zlib.h>
 
 #include "base/bit_utils.h"
 #include "base/logging.h"
@@ -161,7 +162,6 @@
     uint32_t total_size = data_section_offset + data_section_size;
 
     dex_file_data_.resize(total_size);
-    std::memcpy(&dex_file_data_[0], header_data.data, sizeof(DexFile::Header));
 
     for (const auto& entry : strings_) {
       CHECK_LT(entry.first.size(), 128u);
@@ -210,7 +210,12 @@
       Write32(raw_offset + 4u, GetStringIdx(entry.first.name));
     }
 
-    // Leave checksum and signature as zeros.
+    // Leave signature as zeros.
+
+    header->file_size_ = dex_file_data_.size();
+    size_t skip = sizeof(header->magic_) + sizeof(header->checksum_);
+    header->checksum_ = adler32(0u, dex_file_data_.data() + skip, dex_file_data_.size() - skip);
+    std::memcpy(&dex_file_data_[0], header_data.data, sizeof(DexFile::Header));
 
     std::string error_msg;
     std::unique_ptr<const DexFile> dex_file(DexFile::Open(
diff --git a/dex2oat/dex2oat.cc b/dex2oat/dex2oat.cc
index ea54239..b97e7ee 100644
--- a/dex2oat/dex2oat.cc
+++ b/dex2oat/dex2oat.cc
@@ -503,6 +503,10 @@
       compiler_kind_(Compiler::kOptimizing),
       instruction_set_(kRuntimeISA),
       // Take the default set of instruction features from the build.
+      image_file_location_oat_checksum_(0),
+      image_file_location_oat_data_begin_(0),
+      image_patch_delta_(0),
+      key_value_store_(nullptr),
       verification_results_(nullptr),
       method_inliner_map_(),
       runtime_(nullptr),
@@ -522,8 +526,14 @@
       boot_image_(false),
       multi_image_(false),
       is_host_(false),
+      class_loader_(nullptr),
+      elf_writers_(),
+      oat_writers_(),
+      rodata_(),
       image_writer_(nullptr),
       driver_(nullptr),
+      opened_dex_files_maps_(),
+      opened_dex_files_(),
       dump_stats_(false),
       dump_passes_(false),
       dump_timing_(false),
@@ -534,11 +544,6 @@
       timings_(timings) {}
 
   ~Dex2Oat() {
-    // Free opened dex files before deleting the runtime_, because ~DexFile
-    // uses MemMap, which is shut down by ~Runtime.
-    class_path_files_.clear();
-    opened_dex_files_.clear();
-
     // Log completion time before deleting the runtime_, because this accesses
     // the runtime.
     LogCompletionTime();
@@ -551,6 +556,9 @@
       for (std::unique_ptr<const DexFile>& dex_file : opened_dex_files_) {
         dex_file.release();
       }
+      for (std::unique_ptr<MemMap>& map : opened_dex_files_maps_) {
+        map.release();
+      }
       for (std::unique_ptr<File>& oat_file : oat_files_) {
         oat_file.release();
       }
@@ -1130,6 +1138,9 @@
   // Check whether the oat output files are writable, and open them for later. Also open a swap
   // file, if a name is given.
   bool OpenFile() {
+    // Prune non-existent dex files now so that we don't create empty oat files for multi-image.
+    PruneNonExistentDexFiles();
+
     // Expand oat and image filenames for multi image.
     if (IsBootImage() && multi_image_) {
       ExpandOatAndImageFilenames();
@@ -1201,9 +1212,6 @@
     }
     // Note that dex2oat won't close the swap_fd_. The compiler driver's swap space will do that.
 
-    // Organize inputs, handling multi-dex and multiple oat file outputs.
-    CreateDexOatMappings();
-
     return true;
   }
 
@@ -1246,89 +1254,135 @@
       return false;
     }
 
+    CreateOatWriters();
+    if (!AddDexFileSources()) {
+      return false;
+    }
+
+    if (IsBootImage() && image_filenames_.size() > 1) {
+      // If we're compiling the boot image, store the boot classpath into the Key-Value store.
+      // We need this for the multi-image case.
+      key_value_store_->Put(OatHeader::kBootClassPath, GetMultiImageBootClassPath());
+    }
+
+    if (!IsBootImage()) {
+      // When compiling an app, create the runtime early to retrieve
+      // the image location key needed for the oat header.
+      if (!CreateRuntime(std::move(runtime_options))) {
+        return false;
+      }
+
+      {
+        TimingLogger::ScopedTiming t3("Loading image checksum", timings_);
+        std::vector<gc::space::ImageSpace*> image_spaces =
+            Runtime::Current()->GetHeap()->GetBootImageSpaces();
+        image_file_location_oat_checksum_ = image_spaces[0]->GetImageHeader().GetOatChecksum();
+        image_file_location_oat_data_begin_ =
+            reinterpret_cast<uintptr_t>(image_spaces[0]->GetImageHeader().GetOatDataBegin());
+        image_patch_delta_ = image_spaces[0]->GetImageHeader().GetPatchDelta();
+        // Store the boot image filename(s).
+        std::vector<std::string> image_filenames;
+        for (const gc::space::ImageSpace* image_space : image_spaces) {
+          image_filenames.push_back(image_space->GetImageFilename());
+        }
+        std::string image_file_location = Join(image_filenames, ':');
+        if (!image_file_location.empty()) {
+          key_value_store_->Put(OatHeader::kImageLocationKey, image_file_location);
+        }
+      }
+
+      // Open dex files for class path.
+      const std::vector<std::string> class_path_locations =
+          GetClassPathLocations(runtime_->GetClassPathString());
+      OpenClassPathFiles(class_path_locations, &class_path_files_);
+
+      // Store the classpath we have right now.
+      std::vector<const DexFile*> class_path_files = MakeNonOwningPointerVector(class_path_files_);
+      key_value_store_->Put(OatHeader::kClassPathKey,
+                            OatFile::EncodeDexFileDependencies(class_path_files));
+    }
+
+    // Now that we have finalized key_value_store_, start writing the oat file.
     {
-      TimingLogger::ScopedTiming t_runtime("Create runtime", timings_);
+      TimingLogger::ScopedTiming t_dex("Writing and opening dex files", timings_);
+      rodata_.reserve(oat_writers_.size());
+      for (size_t i = 0, size = oat_writers_.size(); i != size; ++i) {
+        rodata_.push_back(elf_writers_[i]->StartRoData());
+        // Unzip or copy dex files straight to the oat file.
+        std::unique_ptr<MemMap> opened_dex_files_map;
+        std::vector<std::unique_ptr<const DexFile>> opened_dex_files;
+        if (!oat_writers_[i]->WriteAndOpenDexFiles(rodata_.back(),
+                                                   oat_files_[i].get(),
+                                                   instruction_set_,
+                                                   instruction_set_features_.get(),
+                                                   key_value_store_.get(),
+                                                   &opened_dex_files_map,
+                                                   &opened_dex_files)) {
+          return false;
+        }
+        dex_files_per_oat_file_.push_back(MakeNonOwningPointerVector(opened_dex_files));
+        if (opened_dex_files_map != nullptr) {
+          opened_dex_files_maps_.push_back(std::move(opened_dex_files_map));
+          for (std::unique_ptr<const DexFile>& dex_file : opened_dex_files) {
+            dex_file_oat_filename_map_.emplace(dex_file.get(), oat_filenames_[i]);
+            opened_dex_files_.push_back(std::move(dex_file));
+          }
+        } else {
+          DCHECK(opened_dex_files.empty());
+        }
+      }
+    }
+
+    dex_files_ = MakeNonOwningPointerVector(opened_dex_files_);
+    if (IsBootImage()) {
+      // For boot image, pass opened dex files to the Runtime::Create().
+      // Note: Runtime acquires ownership of these dex files.
+      runtime_options.Set(RuntimeArgumentMap::BootClassPathDexList, &opened_dex_files_);
       if (!CreateRuntime(std::move(runtime_options))) {
         return false;
       }
     }
 
-    // Runtime::Create acquired the mutator_lock_ that is normally given away when we
-    // Runtime::Start, give it away now so that we don't starve GC.
-    Thread* self = Thread::Current();
-    self->TransitionFromRunnableToSuspended(kNative);
     // If we're doing the image, override the compiler filter to force full compilation. Must be
     // done ahead of WellKnownClasses::Init that causes verification.  Note: doesn't force
     // compilation of class initializers.
     // Whilst we're in native take the opportunity to initialize well known classes.
+    Thread* self = Thread::Current();
     WellKnownClasses::Init(self->GetJniEnv());
 
     ClassLinker* const class_linker = Runtime::Current()->GetClassLinker();
-    if (boot_image_filename_.empty()) {
-      dex_files_ = class_linker->GetBootClassPath();
-      // Prune invalid dex locations.
-      for (size_t i = 0; i < dex_locations_.size(); i++) {
-        const char* dex_location = dex_locations_[i];
-        bool contains = false;
-        for (const DexFile* dex_file : dex_files_) {
-          if (strcmp(dex_location, dex_file->GetLocation().c_str()) == 0) {
-            contains = true;
-            break;
-          }
-        }
-        if (!contains) {
-          dex_locations_.erase(dex_locations_.begin() + i);
-          i--;
-        }
-      }
-    } else {
-      TimingLogger::ScopedTiming t_dex("Opening dex files", timings_);
-      if (dex_filenames_.empty()) {
-        ATRACE_BEGIN("Opening zip archive from file descriptor");
-        std::string error_msg;
-        std::unique_ptr<ZipArchive> zip_archive(ZipArchive::OpenFromFd(zip_fd_,
-                                                                       zip_location_.c_str(),
-                                                                       &error_msg));
-        if (zip_archive.get() == nullptr) {
-          LOG(ERROR) << "Failed to open zip from file descriptor for '" << zip_location_ << "': "
-              << error_msg;
-          return false;
-        }
-        if (!DexFile::OpenFromZip(*zip_archive.get(), zip_location_, &error_msg, &opened_dex_files_)) {
-          LOG(ERROR) << "Failed to open dex from file descriptor for zip file '" << zip_location_
-              << "': " << error_msg;
-          return false;
-        }
-        for (auto& dex_file : opened_dex_files_) {
-          dex_files_.push_back(dex_file.get());
-        }
-        ATRACE_END();
-      } else {
-        size_t failure_count = OpenDexFiles(dex_filenames_, dex_locations_, &opened_dex_files_);
-        if (failure_count > 0) {
-          LOG(ERROR) << "Failed to open some dex files: " << failure_count;
-          return false;
-        }
-        for (auto& dex_file : opened_dex_files_) {
-          dex_files_.push_back(dex_file.get());
-        }
-      }
-
+    if (!IsBootImage()) {
       constexpr bool kSaveDexInput = false;
       if (kSaveDexInput) {
         SaveDexInput();
       }
+
+      // Handle and ClassLoader creation needs to come after Runtime::Create.
+      ScopedObjectAccess soa(self);
+
+      // Classpath: first the class-path given.
+      std::vector<const DexFile*> class_path_files = MakeNonOwningPointerVector(class_path_files_);
+
+      // Then the dex files we'll compile. Thus we'll resolve the class-path first.
+      class_path_files.insert(class_path_files.end(), dex_files_.begin(), dex_files_.end());
+
+      class_loader_ = class_linker->CreatePathClassLoader(self, class_path_files);
     }
-    // Ensure opened dex files are writable for dex-to-dex transformations. Also ensure that
-    // the dex caches stay live since we don't want class unloading to occur during compilation.
-    for (const auto& dex_file : dex_files_) {
-      if (!dex_file->EnableWrite()) {
-        PLOG(ERROR) << "Failed to make .dex file writeable '" << dex_file->GetLocation() << "'\n";
+
+    // Ensure opened dex files are writable for dex-to-dex transformations.
+    for (const std::unique_ptr<MemMap>& map : opened_dex_files_maps_) {
+      if (!map->Protect(PROT_READ | PROT_WRITE)) {
+        PLOG(ERROR) << "Failed to make .dex files writeable.";
+        return false;
       }
+    }
+
+    // Ensure that the dex caches stay live since we don't want class unloading
+    // to occur during compilation.
+    for (const auto& dex_file : dex_files_) {
       ScopedObjectAccess soa(self);
       dex_caches_.push_back(soa.AddLocalReference<jobject>(
           class_linker->RegisterDexFile(*dex_file, Runtime::Current()->GetLinearAlloc())));
-      dex_file->CreateTypeLookupTable();
     }
 
     /*
@@ -1353,59 +1407,11 @@
     return true;
   }
 
-  void CreateDexOatMappings() {
-    if (oat_files_.size() > 1) {
-      size_t index = 0;
-      for (size_t i = 0; i < oat_files_.size(); ++i) {
-        std::vector<const DexFile*> dex_files;
-        if (index < dex_files_.size()) {
-          dex_files.push_back(dex_files_[index]);
-          dex_file_oat_filename_map_.emplace(dex_files_[index], oat_filenames_[i]);
-          index++;
-          while (index < dex_files_.size() &&
-              (dex_files_[index]->GetBaseLocation() == dex_files_[index - 1]->GetBaseLocation())) {
-            dex_file_oat_filename_map_.emplace(dex_files_[index], oat_filenames_[i]);
-            dex_files.push_back(dex_files_[index]);
-            index++;
-          }
-        }
-        dex_files_per_oat_file_.push_back(std::move(dex_files));
-      }
-    } else {
-      dex_files_per_oat_file_.push_back(dex_files_);
-      for (const DexFile* dex_file : dex_files_) {
-        dex_file_oat_filename_map_.emplace(dex_file, oat_filenames_[0]);
-      }
-    }
-  }
-
   // Create and invoke the compiler driver. This will compile all the dex files.
   void Compile() {
     TimingLogger::ScopedTiming t("dex2oat Compile", timings_);
     compiler_phases_timings_.reset(new CumulativeLogger("compilation times"));
 
-    // Handle and ClassLoader creation needs to come after Runtime::Create
-    jobject class_loader = nullptr;
-    Thread* self = Thread::Current();
-
-    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 = MakeNonOwningPointerVector(class_path_files_);
-
-      // Store the classpath we have right now.
-      key_value_store_->Put(OatHeader::kClassPathKey,
-                            OatFile::EncodeDexFileDependencies(class_path_files));
-
-      // Then the dex files we'll compile. Thus we'll resolve the class-path first.
-      class_path_files.insert(class_path_files.end(), dex_files_.begin(), dex_files_.end());
-
-      class_loader = class_linker->CreatePathClassLoader(self, class_path_files);
-    }
-
     // Find the dex file we should not inline from.
 
     // For now, on the host always have core-oj removed.
@@ -1453,49 +1459,6 @@
       }
     }
 
-    if (IsBootImage() && image_filenames_.size() > 1) {
-      // If we're compiling the boot image, store the boot classpath into the Key-Value store. If
-      // the image filename was adapted (e.g., for our tests), we need to change this here, too, but
-      // need to strip all path components (they will be re-established when loading).
-      // We need this for the multi-image case.
-      std::ostringstream bootcp_oss;
-      bool first_bootcp = true;
-      for (size_t i = 0; i < dex_locations_.size(); ++i) {
-        if (!first_bootcp) {
-          bootcp_oss << ":";
-        }
-
-        std::string dex_loc = dex_locations_[i];
-        std::string image_filename = image_filenames_[i];
-
-        // Use the dex_loc path, but the image_filename name (without path elements).
-        size_t dex_last_slash = dex_loc.rfind('/');
-
-        // npos is max(size_t). That makes this a bit ugly.
-        size_t image_last_slash = image_filename.rfind('/');
-        size_t image_last_at = image_filename.rfind('@');
-        size_t image_last_sep = (image_last_slash == std::string::npos)
-                                    ? image_last_at
-                                    : (image_last_at == std::string::npos)
-                                          ? std::string::npos
-                                          : std::max(image_last_slash, image_last_at);
-        // Note: whenever image_last_sep == npos, +1 overflow means using the full string.
-
-        if (dex_last_slash == std::string::npos) {
-          dex_loc = image_filename.substr(image_last_sep + 1);
-        } else {
-          dex_loc = dex_loc.substr(0, dex_last_slash + 1) +
-              image_filename.substr(image_last_sep + 1);
-        }
-
-        // Image filenames already end with .art, no need to replace.
-
-        bootcp_oss << dex_loc;
-        first_bootcp = false;
-      }
-      key_value_store_->Put(OatHeader::kBootClassPath, bootcp_oss.str());
-    }
-
     driver_.reset(new CompilerDriver(compiler_options_.get(),
                                      verification_results_.get(),
                                      &method_inliner_map_,
@@ -1516,7 +1479,7 @@
                                      &dex_file_oat_filename_map_,
                                      profile_compilation_info_.get()));
     driver_->SetDexFilesForOatFile(dex_files_);
-    driver_->CompileAll(class_loader, dex_files_, timings_);
+    driver_->CompileAll(class_loader_, dex_files_, timings_);
   }
 
   // Notes on the interleaving of creating the images and oat files to
@@ -1584,19 +1547,18 @@
   // ImageWriter, if necessary.
   // Note: Flushing (and closing) the file is the caller's responsibility, except for the failure
   //       case (when the file will be explicitly erased).
-  bool CreateOatFiles() {
-    CHECK(key_value_store_.get() != nullptr);
-
+  bool WriteOatFiles() {
     TimingLogger::ScopedTiming t("dex2oat Oat", timings_);
 
-    std::vector<std::unique_ptr<OatWriter>> oat_writers;
-    {
-      TimingLogger::ScopedTiming t2("dex2oat OatWriter", timings_);
-      std::string image_file_location;
-      uint32_t image_file_location_oat_checksum = 0;
-      uintptr_t image_file_location_oat_data_begin = 0;
-      int32_t image_patch_delta = 0;
+    // Sync the data to the file, in case we did dex2dex transformations.
+    for (const std::unique_ptr<MemMap>& map : opened_dex_files_maps_) {
+      if (!map->Sync()) {
+        PLOG(ERROR) << "Failed to Sync() dex2dex output. Map: " << map->GetName();
+        return false;
+      }
+    }
 
+    if (IsImage()) {
       if (app_image_ && image_base_ == 0) {
         std::vector<gc::space::ImageSpace*> image_spaces =
             Runtime::Current()->GetHeap()->GetBootImageSpaces();
@@ -1608,47 +1570,15 @@
         VLOG(compiler) << "App image base=" << reinterpret_cast<void*>(image_base_);
       }
 
-      if (IsImage()) {
-        PrepareImageWriter(image_base_);
-      }
+      image_writer_.reset(new ImageWriter(*driver_,
+                                          image_base_,
+                                          compiler_options_->GetCompilePic(),
+                                          IsAppImage(),
+                                          image_storage_mode_,
+                                          oat_filenames_,
+                                          dex_file_oat_filename_map_));
 
-      if (!IsBootImage()) {
-        TimingLogger::ScopedTiming t3("Loading image checksum", timings_);
-        std::vector<gc::space::ImageSpace*> image_spaces =
-            Runtime::Current()->GetHeap()->GetBootImageSpaces();
-        image_file_location_oat_checksum = image_spaces[0]->GetImageHeader().GetOatChecksum();
-        image_file_location_oat_data_begin =
-            reinterpret_cast<uintptr_t>(image_spaces[0]->GetImageHeader().GetOatDataBegin());
-        image_patch_delta = image_spaces[0]->GetImageHeader().GetPatchDelta();
-        std::vector<std::string> image_filenames;
-        for (const gc::space::ImageSpace* image_space : image_spaces) {
-          image_filenames.push_back(image_space->GetImageFilename());
-        }
-        image_file_location = Join(image_filenames, ':');
-      }
-
-      if (!image_file_location.empty()) {
-        key_value_store_->Put(OatHeader::kImageLocationKey, image_file_location);
-      }
-
-      for (size_t i = 0; i < oat_files_.size(); ++i) {
-        std::vector<const DexFile*>& dex_files = dex_files_per_oat_file_[i];
-        std::unique_ptr<OatWriter> oat_writer(new OatWriter(dex_files,
-                                                            image_file_location_oat_checksum,
-                                                            image_file_location_oat_data_begin,
-                                                            image_patch_delta,
-                                                            driver_.get(),
-                                                            image_writer_.get(),
-                                                            IsBootImage(),
-                                                            timings_,
-                                                            key_value_store_.get()));
-        oat_writers.push_back(std::move(oat_writer));
-      }
-    }
-
-    if (IsImage()) {
-      // The OatWriter constructor has already updated offsets in methods and we need to
-      // prepare method offsets in the image address space for direct method patching.
+      // We need to prepare method offsets in the image address space for direct method patching.
       TimingLogger::ScopedTiming t2("dex2oat Prepare image address space", timings_);
       if (!image_writer_->PrepareImageAddressSpace()) {
         LOG(ERROR) << "Failed to prepare image address space.";
@@ -1658,20 +1588,22 @@
 
     {
       TimingLogger::ScopedTiming t2("dex2oat Write ELF", timings_);
-      for (size_t i = 0; i < oat_files_.size(); ++i) {
+      for (size_t i = 0, size = oat_files_.size(); i != size; ++i) {
         std::unique_ptr<File>& oat_file = oat_files_[i];
-        std::unique_ptr<OatWriter>& oat_writer = oat_writers[i];
-        std::unique_ptr<ElfWriter> elf_writer =
-            CreateElfWriterQuick(instruction_set_, compiler_options_.get(), oat_file.get());
+        std::unique_ptr<ElfWriter>& elf_writer = elf_writers_[i];
+        std::unique_ptr<OatWriter>& oat_writer = oat_writers_[i];
 
-        elf_writer->Start();
+        std::vector<const DexFile*>& dex_files = dex_files_per_oat_file_[i];
+        oat_writer->PrepareLayout(driver_.get(), image_writer_.get(), dex_files);
 
-        OutputStream* rodata = elf_writer->StartRoData();
+        OutputStream*& rodata = rodata_[i];
+        DCHECK(rodata != nullptr);
         if (!oat_writer->WriteRodata(rodata)) {
           LOG(ERROR) << "Failed to write .rodata section to the ELF file " << oat_file->GetPath();
           return false;
         }
         elf_writer->EndRoData(rodata);
+        rodata = nullptr;
 
         OutputStream* text = elf_writer->StartText();
         if (!oat_writer->WriteCode(text)) {
@@ -1680,6 +1612,14 @@
         }
         elf_writer->EndText(text);
 
+        if (!oat_writer->WriteHeader(elf_writer->GetStream(),
+                                     image_file_location_oat_checksum_,
+                                     image_file_location_oat_data_begin_,
+                                     image_patch_delta_)) {
+          LOG(ERROR) << "Failed to write oat header to the ELF file " << oat_file->GetPath();
+          return false;
+        }
+
         elf_writer->SetBssSize(oat_writer->GetBssSize());
         elf_writer->WriteDynamicSection();
         elf_writer->WriteDebugInfo(oat_writer->GetMethodDebugInfo());
@@ -1705,6 +1645,9 @@
         }
 
         VLOG(compiler) << "Oat file written successfully: " << oat_filenames_[i];
+
+        oat_writer.reset();
+        elf_writer.reset();
       }
     }
 
@@ -1852,65 +1795,78 @@
     return result;
   }
 
-  static size_t OpenDexFiles(std::vector<const char*>& dex_filenames,
-                             std::vector<const char*>& dex_locations,
-                             std::vector<std::unique_ptr<const DexFile>>* dex_files) {
-    DCHECK(dex_files != nullptr) << "OpenDexFiles out-param is nullptr";
-    size_t failure_count = 0;
-    for (size_t i = 0; i < dex_filenames.size(); i++) {
-      const char* dex_filename = dex_filenames[i];
-      const char* dex_location = dex_locations[i];
-      ATRACE_BEGIN(StringPrintf("Opening dex file '%s'", dex_filenames[i]).c_str());
-      std::string error_msg;
-      if (!OS::FileExists(dex_filename)) {
-        LOG(WARNING) << "Skipping non-existent dex file '" << dex_filename << "'";
-        dex_filenames.erase(dex_filenames.begin() + i);
-        dex_locations.erase(dex_locations.begin() + i);
-        i--;
-        continue;
+  std::string GetMultiImageBootClassPath() {
+    DCHECK(IsBootImage());
+    DCHECK_GT(oat_filenames_.size(), 1u);
+    // If the image filename was adapted (e.g., for our tests), we need to change this here,
+    // too, but need to strip all path components (they will be re-established when loading).
+    std::ostringstream bootcp_oss;
+    bool first_bootcp = true;
+    for (size_t i = 0; i < dex_locations_.size(); ++i) {
+      if (!first_bootcp) {
+        bootcp_oss << ":";
       }
-      if (!DexFile::Open(dex_filename, dex_location, &error_msg, dex_files)) {
-        LOG(WARNING) << "Failed to open .dex from file '" << dex_filename << "': " << error_msg;
-        ++failure_count;
+
+      std::string dex_loc = dex_locations_[i];
+      std::string image_filename = image_filenames_[i];
+
+      // Use the dex_loc path, but the image_filename name (without path elements).
+      size_t dex_last_slash = dex_loc.rfind('/');
+
+      // npos is max(size_t). That makes this a bit ugly.
+      size_t image_last_slash = image_filename.rfind('/');
+      size_t image_last_at = image_filename.rfind('@');
+      size_t image_last_sep = (image_last_slash == std::string::npos)
+                                  ? image_last_at
+                                  : (image_last_at == std::string::npos)
+                                        ? std::string::npos
+                                        : std::max(image_last_slash, image_last_at);
+      // Note: whenever image_last_sep == npos, +1 overflow means using the full string.
+
+      if (dex_last_slash == std::string::npos) {
+        dex_loc = image_filename.substr(image_last_sep + 1);
+      } else {
+        dex_loc = dex_loc.substr(0, dex_last_slash + 1) +
+            image_filename.substr(image_last_sep + 1);
       }
-      ATRACE_END();
+
+      // Image filenames already end with .art, no need to replace.
+
+      bootcp_oss << dex_loc;
+      first_bootcp = false;
     }
-    return failure_count;
+    return bootcp_oss.str();
   }
 
-  // Returns true if dex_files has a dex with the named location. We compare canonical locations,
-  // so that relative and absolute paths will match. Not caching for the dex_files isn't very
-  // efficient, but under normal circumstances the list is neither large nor is this part too
-  // sensitive.
-  static bool DexFilesContains(const std::vector<const DexFile*>& dex_files,
-                               const std::string& location) {
-    std::string canonical_location(DexFile::GetDexCanonicalLocation(location.c_str()));
-    for (size_t i = 0; i < dex_files.size(); ++i) {
-      if (DexFile::GetDexCanonicalLocation(dex_files[i]->GetLocation().c_str()) ==
-          canonical_location) {
-        return true;
-      }
+  std::vector<std::string> GetClassPathLocations(const std::string& class_path) {
+    // This function is used only for apps and for an app we have exactly one oat file.
+    DCHECK(!IsBootImage());
+    DCHECK_EQ(oat_writers_.size(), 1u);
+    std::vector<std::string> dex_files_canonical_locations;
+    for (const char* location : oat_writers_[0]->GetSourceLocations()) {
+      dex_files_canonical_locations.push_back(DexFile::GetDexCanonicalLocation(location));
     }
-    return false;
-  }
 
-  // Appends to opened_dex_files any elements of class_path that dex_files
-  // doesn't already contain. This will open those dex files as necessary.
-  static void OpenClassPathFiles(const std::string& class_path,
-                                 std::vector<const DexFile*> dex_files,
-                                 std::vector<std::unique_ptr<const DexFile>>* opened_dex_files) {
-    DCHECK(opened_dex_files != nullptr) << "OpenClassPathFiles out-param is nullptr";
     std::vector<std::string> parsed;
     Split(class_path, ':', &parsed);
-    // Take Locks::mutator_lock_ so that lock ordering on the ClassLinker::dex_lock_ is maintained.
-    ScopedObjectAccess soa(Thread::Current());
-    for (size_t i = 0; i < parsed.size(); ++i) {
-      if (DexFilesContains(dex_files, parsed[i])) {
-        continue;
-      }
+    auto kept_it = std::remove_if(parsed.begin(),
+                                  parsed.end(),
+                                  [dex_files_canonical_locations](const std::string& location) {
+      return ContainsElement(dex_files_canonical_locations,
+                             DexFile::GetDexCanonicalLocation(location.c_str()));
+    });
+    parsed.erase(kept_it, parsed.end());
+    return parsed;
+  }
+
+  // Opens requested class path files and appends them to opened_dex_files.
+  static void OpenClassPathFiles(const std::vector<std::string>& class_path_locations,
+                                 std::vector<std::unique_ptr<const DexFile>>* opened_dex_files) {
+    DCHECK(opened_dex_files != nullptr) << "OpenClassPathFiles out-param is nullptr";
+    for (const std::string& location : class_path_locations) {
       std::string error_msg;
-      if (!DexFile::Open(parsed[i].c_str(), parsed[i].c_str(), &error_msg, opened_dex_files)) {
-        LOG(WARNING) << "Failed to open dex file '" << parsed[i] << "': " << error_msg;
+      if (!DexFile::Open(location.c_str(), location.c_str(), &error_msg, opened_dex_files)) {
+        LOG(WARNING) << "Failed to open dex file '" << location << "': " << error_msg;
       }
     }
   }
@@ -1985,6 +1941,63 @@
     return true;
   }
 
+  void PruneNonExistentDexFiles() {
+    DCHECK_EQ(dex_filenames_.size(), dex_locations_.size());
+    size_t kept = 0u;
+    for (size_t i = 0, size = dex_filenames_.size(); i != size; ++i) {
+      if (!OS::FileExists(dex_filenames_[i])) {
+        LOG(WARNING) << "Skipping non-existent dex file '" << dex_filenames_[i] << "'";
+      } else {
+        dex_filenames_[kept] = dex_filenames_[i];
+        dex_locations_[kept] = dex_locations_[i];
+        ++kept;
+      }
+    }
+    dex_filenames_.resize(kept);
+    dex_locations_.resize(kept);
+  }
+
+  bool AddDexFileSources() {
+    TimingLogger::ScopedTiming t2("AddDexFileSources", timings_);
+    if (zip_fd_ != -1) {
+      DCHECK_EQ(oat_writers_.size(), 1u);
+      if (!oat_writers_[0]->AddZippedDexFilesSource(ScopedFd(zip_fd_), zip_location_.c_str())) {
+        return false;
+      }
+    } else if (oat_writers_.size() > 1u) {
+      // Multi-image.
+      DCHECK_EQ(oat_writers_.size(), dex_filenames_.size());
+      DCHECK_EQ(oat_writers_.size(), dex_locations_.size());
+      for (size_t i = 0, size = oat_writers_.size(); i != size; ++i) {
+        if (!oat_writers_[i]->AddDexFileSource(dex_filenames_[i], dex_locations_[i])) {
+          return false;
+        }
+      }
+    } else {
+      DCHECK_EQ(oat_writers_.size(), 1u);
+      DCHECK_EQ(dex_filenames_.size(), dex_locations_.size());
+      DCHECK_NE(dex_filenames_.size(), 0u);
+      for (size_t i = 0; i != dex_filenames_.size(); ++i) {
+        if (!oat_writers_[0]->AddDexFileSource(dex_filenames_[i], dex_locations_[i])) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+
+  void CreateOatWriters() {
+    TimingLogger::ScopedTiming t2("CreateOatWriters", timings_);
+    elf_writers_.reserve(oat_files_.size());
+    oat_writers_.reserve(oat_files_.size());
+    for (const std::unique_ptr<File>& oat_file : oat_files_) {
+      elf_writers_.emplace_back(
+          CreateElfWriterQuick(instruction_set_, compiler_options_.get(), oat_file.get()));
+      elf_writers_.back()->Start();
+      oat_writers_.emplace_back(new OatWriter(IsBootImage(), timings_));
+    }
+  }
+
   void SaveDexInput() {
     for (size_t i = 0; i < dex_files_.size(); ++i) {
       const DexFile* dex_file = dex_files_[i];
@@ -2044,8 +2057,8 @@
   }
 
   // Create a runtime necessary for compilation.
-  bool CreateRuntime(RuntimeArgumentMap&& runtime_options)
-      SHARED_TRYLOCK_FUNCTION(true, Locks::mutator_lock_) {
+  bool CreateRuntime(RuntimeArgumentMap&& runtime_options) {
+    TimingLogger::ScopedTiming t_runtime("Create runtime", timings_);
     if (!Runtime::Create(std::move(runtime_options))) {
       LOG(ERROR) << "Failed to create runtime";
       return false;
@@ -2066,18 +2079,12 @@
 
     runtime_->GetClassLinker()->RunRootClinits();
 
-    return true;
-  }
+    // Runtime::Create acquired the mutator_lock_ that is normally given away when we
+    // Runtime::Start, give it away now so that we don't starve GC.
+    Thread* self = Thread::Current();
+    self->TransitionFromRunnableToSuspended(kNative);
 
-  void PrepareImageWriter(uintptr_t image_base) {
-    DCHECK(IsImage());
-    image_writer_.reset(new ImageWriter(*driver_,
-                                        image_base,
-                                        compiler_options_->GetCompilePic(),
-                                        IsAppImage(),
-                                        image_storage_mode_,
-                                        oat_filenames_,
-                                        dex_file_oat_filename_map_));
+    return true;
   }
 
   // Let the ImageWriter write the image files. If we do not compile PIC, also fix up the oat files.
@@ -2256,6 +2263,9 @@
   InstructionSet instruction_set_;
   std::unique_ptr<const InstructionSetFeatures> instruction_set_features_;
 
+  uint32_t image_file_location_oat_checksum_;
+  uintptr_t image_file_location_oat_data_begin_;
+  int32_t image_patch_delta_;
   std::unique_ptr<SafeMap<std::string, std::string> > key_value_store_;
 
   std::unique_ptr<VerificationResults> verification_results_;
@@ -2263,11 +2273,11 @@
   DexFileToMethodInlinerMap method_inliner_map_;
   std::unique_ptr<QuickCompilerCallbacks> callbacks_;
 
+  std::unique_ptr<Runtime> runtime_;
+
   // Ownership for the class path files.
   std::vector<std::unique_ptr<const DexFile>> class_path_files_;
 
-  std::unique_ptr<Runtime> runtime_;
-
   size_t thread_count_;
   uint64_t start_ns_;
   std::unique_ptr<WatchDog> watchdog_;
@@ -2302,11 +2312,17 @@
   std::vector<const DexFile*> dex_files_;
   std::string no_inline_from_string_;
   std::vector<jobject> dex_caches_;
-  std::vector<std::unique_ptr<const DexFile>> opened_dex_files_;
+  jobject class_loader_;
 
+  std::vector<std::unique_ptr<ElfWriter>> elf_writers_;
+  std::vector<std::unique_ptr<OatWriter>> oat_writers_;
+  std::vector<OutputStream*> rodata_;
   std::unique_ptr<ImageWriter> image_writer_;
   std::unique_ptr<CompilerDriver> driver_;
 
+  std::vector<std::unique_ptr<MemMap>> opened_dex_files_maps_;
+  std::vector<std::unique_ptr<const DexFile>> opened_dex_files_;
+
   std::vector<std::string> verbose_methods_;
   bool dump_stats_;
   bool dump_passes_;
@@ -2355,7 +2371,7 @@
 static int CompileImage(Dex2Oat& dex2oat) {
   dex2oat.Compile();
 
-  if (!dex2oat.CreateOatFiles()) {
+  if (!dex2oat.WriteOatFiles()) {
     dex2oat.EraseOatFiles();
     return EXIT_FAILURE;
   }
@@ -2394,7 +2410,7 @@
 static int CompileApp(Dex2Oat& dex2oat) {
   dex2oat.Compile();
 
-  if (!dex2oat.CreateOatFiles()) {
+  if (!dex2oat.WriteOatFiles()) {
     dex2oat.EraseOatFiles();
     return EXIT_FAILURE;
   }
@@ -2451,6 +2467,11 @@
     }
   }
 
+  // Check early that the result of compilation can be written
+  if (!dex2oat.OpenFile()) {
+    return EXIT_FAILURE;
+  }
+
   // Print the complete line when any of the following is true:
   //   1) Debug build
   //   2) Compiling an image
@@ -2464,11 +2485,6 @@
   }
 
   if (!dex2oat.Setup()) {
-    return EXIT_FAILURE;
-  }
-
-  // Check early that the result of compilation can be written
-  if (!dex2oat.OpenFile()) {
     dex2oat.EraseOatFiles();
     return EXIT_FAILURE;
   }
diff --git a/runtime/dex_file.cc b/runtime/dex_file.cc
index bc8ba97..9b93c13 100644
--- a/runtime/dex_file.cc
+++ b/runtime/dex_file.cc
@@ -687,8 +687,8 @@
   return nullptr;
 }
 
-void DexFile::CreateTypeLookupTable() const {
-  lookup_table_.reset(TypeLookupTable::Create(*this));
+void DexFile::CreateTypeLookupTable(uint8_t* storage) const {
+  lookup_table_.reset(TypeLookupTable::Create(*this, storage));
 }
 
 // Given a signature place the type ids into the given vector
diff --git a/runtime/dex_file.h b/runtime/dex_file.h
index 8a3db6c..facb6fd 100644
--- a/runtime/dex_file.h
+++ b/runtime/dex_file.h
@@ -1157,7 +1157,7 @@
     return lookup_table_.get();
   }
 
-  void CreateTypeLookupTable() const;
+  void CreateTypeLookupTable(uint8_t* storage = nullptr) const;
 
  private:
   // Opens a .dex file
diff --git a/runtime/mem_map.cc b/runtime/mem_map.cc
index 3571edb..18c52e4 100644
--- a/runtime/mem_map.cc
+++ b/runtime/mem_map.cc
@@ -583,6 +583,10 @@
   }
 }
 
+bool MemMap::Sync() {
+  return msync(BaseBegin(), BaseSize(), MS_SYNC) == 0;
+}
+
 bool MemMap::Protect(int prot) {
   if (base_begin_ == nullptr && base_size_ == 0) {
     prot_ = prot;
diff --git a/runtime/mem_map.h b/runtime/mem_map.h
index ed21365..ebd550a 100644
--- a/runtime/mem_map.h
+++ b/runtime/mem_map.h
@@ -126,6 +126,8 @@
     return name_;
   }
 
+  bool Sync();
+
   bool Protect(int prot);
 
   void MadviseDontNeedAndZero();
diff --git a/runtime/oat.h b/runtime/oat.h
index 13fd6a4..989e3f9 100644
--- a/runtime/oat.h
+++ b/runtime/oat.h
@@ -31,7 +31,7 @@
 class PACKED(4) OatHeader {
  public:
   static constexpr uint8_t kOatMagic[] = { 'o', 'a', 't', '\n' };
-  static constexpr uint8_t kOatVersion[] = { '0', '7', '4', '\0' };
+  static constexpr uint8_t kOatVersion[] = { '0', '7', '5', '\0' };
 
   static constexpr const char* kImageLocationKey = "image-location";
   static constexpr const char* kDex2OatCmdLineKey = "dex2oat-cmdline";
diff --git a/runtime/oat_file.cc b/runtime/oat_file.cc
index 83e594b..3babcf7 100644
--- a/runtime/oat_file.cc
+++ b/runtime/oat_file.cc
@@ -46,6 +46,7 @@
 #include "oat_file_manager.h"
 #include "os.h"
 #include "runtime.h"
+#include "type_lookup_table.h"
 #include "utils.h"
 #include "utils/dex_cache_arrays_layout-inl.h"
 #include "vmap_table.h"
@@ -266,16 +267,15 @@
                                 i);
       return false;
     }
-
-    const char* dex_file_location_data = reinterpret_cast<const char*>(oat);
-    oat += dex_file_location_size;
-    if (UNLIKELY(oat > End())) {
+    if (UNLIKELY(static_cast<size_t>(End() - oat) < dex_file_location_size)) {
       *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zu with truncated dex file "
                                     "location",
                                 GetLocation().c_str(),
                                 i);
       return false;
     }
+    const char* dex_file_location_data = reinterpret_cast<const char*>(oat);
+    oat += dex_file_location_size;
 
     std::string dex_file_location = ResolveRelativeEncodedDexLocation(
         abs_dex_location,
@@ -318,6 +318,17 @@
                                 Size());
       return false;
     }
+    if (UNLIKELY(Size() - dex_file_offset < sizeof(DexFile::Header))) {
+      *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zu for '%s' with dex file "
+                                    "offset %u of %zu but the size of dex file header is %zu",
+                                GetLocation().c_str(),
+                                i,
+                                dex_file_location.c_str(),
+                                dex_file_offset,
+                                Size(),
+                                sizeof(DexFile::Header));
+      return false;
+    }
 
     const uint8_t* dex_file_pointer = Begin() + dex_file_offset;
     if (UNLIKELY(!DexFile::IsMagicValid(dex_file_pointer))) {
@@ -339,34 +350,75 @@
       return false;
     }
     const DexFile::Header* header = reinterpret_cast<const DexFile::Header*>(dex_file_pointer);
+    if (Size() - dex_file_offset < header->file_size_) {
+      *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zu for '%s' with dex file "
+                                    "offset %u and size %u truncated at %zu",
+                                GetLocation().c_str(),
+                                i,
+                                dex_file_location.c_str(),
+                                dex_file_offset,
+                                header->file_size_,
+                                Size());
+      return false;
+    }
 
-    if (UNLIKELY(oat > End())) {
-      *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zd for '%s' with truncated "
-                                "lookup table offset", GetLocation().c_str(), i,
+    uint32_t class_offsets_offset;
+    if (UNLIKELY(!ReadOatDexFileData(*this, &oat, &class_offsets_offset))) {
+      *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zu for '%s' truncated "
+                                    "after class offsets offset",
+                                GetLocation().c_str(),
+                                i,
                                 dex_file_location.c_str());
       return false;
     }
-    uint32_t lookup_table_offset = *reinterpret_cast<const uint32_t*>(oat);
-    oat += sizeof(lookup_table_offset);
-    if (Begin() + lookup_table_offset > End()) {
-      *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zd for '%s' with truncated "
-                                "lookup table", GetLocation().c_str(), i,
+    if (UNLIKELY(class_offsets_offset > Size()) ||
+        UNLIKELY((Size() - class_offsets_offset) / sizeof(uint32_t) < header->class_defs_size_)) {
+      *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zu for '%s' with truncated "
+                                    "class offsets, offset %u of %zu, class defs %u",
+                                GetLocation().c_str(),
+                                i,
+                                dex_file_location.c_str(),
+                                class_offsets_offset,
+                                Size(),
+                                header->class_defs_size_);
+      return false;
+    }
+    if (UNLIKELY(!IsAligned<alignof(uint32_t)>(class_offsets_offset))) {
+      *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zu for '%s' with unaligned "
+                                    "class offsets, offset %u",
+                                GetLocation().c_str(),
+                                i,
+                                dex_file_location.c_str(),
+                                class_offsets_offset);
+      return false;
+    }
+    const uint32_t* class_offsets_pointer =
+        reinterpret_cast<const uint32_t*>(Begin() + class_offsets_offset);
+
+    uint32_t lookup_table_offset;
+    if (UNLIKELY(!ReadOatDexFileData(*this, &oat, &lookup_table_offset))) {
+      *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zd for '%s' truncated "
+                                    "after lookup table offset",
+                                GetLocation().c_str(),
+                                i,
                                 dex_file_location.c_str());
       return false;
     }
     const uint8_t* lookup_table_data = lookup_table_offset != 0u
         ? Begin() + lookup_table_offset
         : nullptr;
-
-    const uint32_t* methods_offsets_pointer = reinterpret_cast<const uint32_t*>(oat);
-
-    oat += (sizeof(*methods_offsets_pointer) * header->class_defs_size_);
-    if (UNLIKELY(oat > End())) {
+    if (lookup_table_offset != 0u &&
+        (UNLIKELY(lookup_table_offset > Size()) ||
+            UNLIKELY(Size() - lookup_table_offset <
+                     TypeLookupTable::RawDataLength(header->class_defs_size_)))) {
       *error_msg = StringPrintf("In oat file '%s' found OatDexFile #%zu for '%s' with truncated "
-                                    "method offsets",
+                                    "type lookup table, offset %u of %zu, class defs %u",
                                 GetLocation().c_str(),
                                 i,
-                                dex_file_location.c_str());
+                                dex_file_location.c_str(),
+                                lookup_table_offset,
+                                Size(),
+                                header->class_defs_size_);
       return false;
     }
 
@@ -398,7 +450,7 @@
                                               dex_file_checksum,
                                               dex_file_pointer,
                                               lookup_table_data,
-                                              methods_offsets_pointer,
+                                              class_offsets_pointer,
                                               current_dex_cache_arrays);
     oat_dex_files_storage_.push_back(oat_dex_file);
 
diff --git a/runtime/parsed_options.cc b/runtime/parsed_options.cc
index 2b92303..341be9a 100644
--- a/runtime/parsed_options.cc
+++ b/runtime/parsed_options.cc
@@ -309,8 +309,8 @@
     const std::string option(options[i].first);
       // TODO: support -Djava.class.path
     if (option == "bootclasspath") {
-      auto boot_class_path
-          = reinterpret_cast<const std::vector<const DexFile*>*>(options[i].second);
+      auto boot_class_path = static_cast<std::vector<std::unique_ptr<const DexFile>>*>(
+          const_cast<void*>(options[i].second));
 
       if (runtime_options != nullptr) {
         runtime_options->Set(M::BootClassPathDexList, boot_class_path);
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index c4694ee..5b075b7 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -1131,10 +1131,14 @@
     }
 
     std::vector<std::unique_ptr<const DexFile>> boot_class_path;
-    OpenDexFiles(dex_filenames,
-                 dex_locations,
-                 runtime_options.GetOrDefault(Opt::Image),
-                 &boot_class_path);
+    if (runtime_options.Exists(Opt::BootClassPathDexList)) {
+      boot_class_path.swap(*runtime_options.GetOrDefault(Opt::BootClassPathDexList));
+    } else {
+      OpenDexFiles(dex_filenames,
+                   dex_locations,
+                   runtime_options.GetOrDefault(Opt::Image),
+                   &boot_class_path);
+    }
     instruction_set_ = runtime_options.GetOrDefault(Opt::ImageInstructionSet);
     std::string error_msg;
     if (!class_linker_->InitWithoutImage(std::move(boot_class_path), &error_msg)) {
diff --git a/runtime/runtime_options.cc b/runtime/runtime_options.cc
index c54461e..e75481c 100644
--- a/runtime/runtime_options.cc
+++ b/runtime/runtime_options.cc
@@ -13,8 +13,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 #include "runtime_options.h"
 
+#include <memory>
+
 #include "gc/heap.h"
 #include "monitor.h"
 #include "runtime.h"
diff --git a/runtime/runtime_options.def b/runtime/runtime_options.def
index 5624285..c5b009d 100644
--- a/runtime/runtime_options.def
+++ b/runtime/runtime_options.def
@@ -117,8 +117,8 @@
 
 // Not parse-able from command line, but can be provided explicitly.
 // (Do not add anything here that is defined in ParsedOptions::MakeParser)
-RUNTIME_OPTIONS_KEY (const std::vector<const DexFile*>*, \
-                                          BootClassPathDexList)  // TODO: make unique_ptr
+RUNTIME_OPTIONS_KEY (std::vector<std::unique_ptr<const DexFile>>*, \
+                                          BootClassPathDexList)
 RUNTIME_OPTIONS_KEY (InstructionSet,      ImageInstructionSet,            kRuntimeISA)
 RUNTIME_OPTIONS_KEY (CompilerCallbacks*,  CompilerCallbacksPtr)  // TDOO: make unique_ptr
 RUNTIME_OPTIONS_KEY (bool (*)(),          HookIsSensitiveThread)
diff --git a/runtime/type_lookup_table.cc b/runtime/type_lookup_table.cc
index 0d40bb7..fc9faec 100644
--- a/runtime/type_lookup_table.cc
+++ b/runtime/type_lookup_table.cc
@@ -16,6 +16,7 @@
 
 #include "type_lookup_table.h"
 
+#include "base/bit_utils.h"
 #include "dex_file-inl.h"
 #include "utf-inl.h"
 #include "utils.h"
@@ -42,25 +43,39 @@
 }
 
 uint32_t TypeLookupTable::RawDataLength(const DexFile& dex_file) {
-  return RoundUpToPowerOfTwo(dex_file.NumClassDefs()) * sizeof(Entry);
+  return RawDataLength(dex_file.NumClassDefs());
 }
 
-TypeLookupTable* TypeLookupTable::Create(const DexFile& dex_file) {
+uint32_t TypeLookupTable::RawDataLength(uint32_t num_class_defs) {
+  return SupportedSize(num_class_defs) ? RoundUpToPowerOfTwo(num_class_defs) * sizeof(Entry) : 0u;
+}
+
+uint32_t TypeLookupTable::CalculateMask(uint32_t num_class_defs) {
+  return SupportedSize(num_class_defs) ? RoundUpToPowerOfTwo(num_class_defs) - 1u : 0u;
+}
+
+bool TypeLookupTable::SupportedSize(uint32_t num_class_defs) {
+  return num_class_defs != 0u && num_class_defs <= std::numeric_limits<uint16_t>::max();
+}
+
+TypeLookupTable* TypeLookupTable::Create(const DexFile& dex_file, uint8_t* storage) {
   const uint32_t num_class_defs = dex_file.NumClassDefs();
-  return (num_class_defs == 0 || num_class_defs > std::numeric_limits<uint16_t>::max())
-      ? nullptr
-      : new TypeLookupTable(dex_file);
+  return SupportedSize(num_class_defs)
+      ? new TypeLookupTable(dex_file, storage)
+      : nullptr;
 }
 
 TypeLookupTable* TypeLookupTable::Open(const uint8_t* raw_data, const DexFile& dex_file) {
   return new TypeLookupTable(raw_data, dex_file);
 }
 
-TypeLookupTable::TypeLookupTable(const DexFile& dex_file)
+TypeLookupTable::TypeLookupTable(const DexFile& dex_file, uint8_t* storage)
     : dex_file_(dex_file),
-      mask_(RoundUpToPowerOfTwo(dex_file.NumClassDefs()) - 1),
-      entries_(new Entry[mask_ + 1]),
-      owns_entries_(true) {
+      mask_(CalculateMask(dex_file.NumClassDefs())),
+      entries_(storage != nullptr ? reinterpret_cast<Entry*>(storage) : new Entry[mask_ + 1]),
+      owns_entries_(storage == nullptr) {
+  static_assert(alignof(Entry) == 4u, "Expecting Entry to be 4-byte aligned.");
+  DCHECK_ALIGNED(storage, alignof(Entry));
   std::vector<uint16_t> conflict_class_defs;
   // The first stage. Put elements on their initial positions. If an initial position is already
   // occupied then delay the insertion of the element to the second stage to reduce probing
@@ -93,7 +108,7 @@
 
 TypeLookupTable::TypeLookupTable(const uint8_t* raw_data, const DexFile& dex_file)
     : dex_file_(dex_file),
-      mask_(RoundUpToPowerOfTwo(dex_file.NumClassDefs()) - 1),
+      mask_(CalculateMask(dex_file.NumClassDefs())),
       entries_(reinterpret_cast<Entry*>(const_cast<uint8_t*>(raw_data))),
       owns_entries_(false) {}
 
diff --git a/runtime/type_lookup_table.h b/runtime/type_lookup_table.h
index 3c2295c..d74d01d 100644
--- a/runtime/type_lookup_table.h
+++ b/runtime/type_lookup_table.h
@@ -60,7 +60,7 @@
   }
 
   // Method creates lookup table for dex file
-  static TypeLookupTable* Create(const DexFile& dex_file);
+  static TypeLookupTable* Create(const DexFile& dex_file, uint8_t* storage = nullptr);
 
   // Method opens lookup table from binary data. Lookup table does not owns binary data.
   static TypeLookupTable* Open(const uint8_t* raw_data, const DexFile& dex_file);
@@ -76,6 +76,9 @@
   // Method returns length of binary data for the specified dex file.
   static uint32_t RawDataLength(const DexFile& dex_file);
 
+  // Method returns length of binary data for the specified number of class definitions.
+  static uint32_t RawDataLength(uint32_t num_class_defs);
+
  private:
    /**
     * To find element we need to compare strings.
@@ -109,8 +112,11 @@
     }
   };
 
+  static uint32_t CalculateMask(uint32_t num_class_defs);
+  static bool SupportedSize(uint32_t num_class_defs);
+
   // Construct from a dex file.
-  explicit TypeLookupTable(const DexFile& dex_file);
+  explicit TypeLookupTable(const DexFile& dex_file, uint8_t* storage);
 
   // Construct from a dex file with existing data.
   TypeLookupTable(const uint8_t* raw_data, const DexFile& dex_file);