compiler/image_writer.cc

   1 /*
   2  * Copyright (C) 2011 The Android Open Source Project
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include "image_writer.h"
  18
  19 #include <sys/stat.h>
  20 #include <lz4.h>
  21 #include <lz4hc.h>
  22
  23 #include <memory>
  24 #include <numeric>
  25 #include <unordered_set>
  26 #include <vector>
  27
  28 #include "art_field-inl.h"
  29 #include "art_method-inl.h"
  30 #include "base/logging.h"
  31 #include "base/unix_file/fd_file.h"
  32 #include "class_linker-inl.h"
  33 #include "compiled_method.h"
  34 #include "dex_file-inl.h"
  35 #include "driver/compiler_driver.h"
  36 #include "elf_file.h"
  37 #include "elf_utils.h"
  38 #include "elf_writer.h"
  39 #include "gc/accounting/card_table-inl.h"
  40 #include "gc/accounting/heap_bitmap.h"
  41 #include "gc/accounting/space_bitmap-inl.h"
  42 #include "gc/heap.h"
  43 #include "gc/space/large_object_space.h"
  44 #include "gc/space/space-inl.h"
  45 #include "globals.h"
  46 #include "image.h"
  47 #include "intern_table.h"
  48 #include "linear_alloc.h"
  49 #include "lock_word.h"
  50 #include "mirror/abstract_method.h"
  51 #include "mirror/array-inl.h"
  52 #include "mirror/class-inl.h"
  53 #include "mirror/class_loader.h"
  54 #include "mirror/dex_cache-inl.h"
  55 #include "mirror/method.h"
  56 #include "mirror/object-inl.h"
  57 #include "mirror/object_array-inl.h"
  58 #include "mirror/string-inl.h"
  59 #include "oat.h"
  60 #include "oat_file.h"
  61 #include "oat_file_manager.h"
  62 #include "runtime.h"
  63 #include "scoped_thread_state_change.h"
  64 #include "handle_scope-inl.h"
  65 #include "utils/dex_cache_arrays_layout-inl.h"
  66
  67 using ::art::mirror::Class;
  68 using ::art::mirror::DexCache;
  69 using ::art::mirror::Object;
  70 using ::art::mirror::ObjectArray;
  71 using ::art::mirror::String;
  72
  73 namespace art {
  74
  75 // Separate objects into multiple bins to optimize dirty memory use.
  76 static constexpr bool kBinObjects = true;
  77
  78 // Return true if an object is already in an image space.
  79 bool ImageWriter::IsInBootImage(const void* obj) const {
  80   gc::Heap* const heap = Runtime::Current()->GetHeap();
  81   if (!compile_app_image_) {
  82     DCHECK(heap->GetBootImageSpaces().empty());
  83     return false;
  84   }
  85   for (gc::space::ImageSpace* boot_image_space : heap->GetBootImageSpaces()) {
  86     const uint8_t* image_begin = boot_image_space->Begin();
  87     // Real image end including ArtMethods and ArtField sections.
  88     const uint8_t* image_end = image_begin + boot_image_space->GetImageHeader().GetImageSize();
  89     if (image_begin <= obj && obj < image_end) {
  90       return true;
  91     }
  92   }
  93   return false;
  94 }
  95
  96 bool ImageWriter::IsInBootOatFile(const void* ptr) const {
  97   gc::Heap* const heap = Runtime::Current()->GetHeap();
  98   if (!compile_app_image_) {
  99     DCHECK(heap->GetBootImageSpaces().empty());
 100     return false;
 101   }
 102   for (gc::space::ImageSpace* boot_image_space : heap->GetBootImageSpaces()) {
 103     const ImageHeader& image_header = boot_image_space->GetImageHeader();
 104     if (image_header.GetOatFileBegin() <= ptr && ptr < image_header.GetOatFileEnd()) {
 105       return true;
 106     }
 107   }
 108   return false;
 109 }
 110
 111 static void CheckNoDexObjectsCallback(Object* obj, void* arg ATTRIBUTE_UNUSED)
 112     SHARED_REQUIRES(Locks::mutator_lock_) {
 113   Class* klass = obj->GetClass();
 114   CHECK_NE(PrettyClass(klass), "com.android.dex.Dex");
 115 }
 116
 117 static void CheckNoDexObjects() {
 118   ScopedObjectAccess soa(Thread::Current());
 119   Runtime::Current()->GetHeap()->VisitObjects(CheckNoDexObjectsCallback, nullptr);
 120 }
 121
 122 bool ImageWriter::PrepareImageAddressSpace() {
 123   target_ptr_size_ = InstructionSetPointerSize(compiler_driver_.GetInstructionSet());
 124   gc::Heap* const heap = Runtime::Current()->GetHeap();
 125   {
 126     ScopedObjectAccess soa(Thread::Current());
 127     PruneNonImageClasses();  // Remove junk
 128     if (!compile_app_image_) {
 129       // Avoid for app image since this may increase RAM and image size.
 130       ComputeLazyFieldsForImageClasses();  // Add useful information
 131     }
 132   }
 133   heap->CollectGarbage(false);  // Remove garbage.
 134
 135   // Dex caches must not have their dex fields set in the image. These are memory buffers of mapped
 136   // dex files.
 137   //
 138   // We may open them in the unstarted-runtime code for class metadata. Their fields should all be
 139   // reset in PruneNonImageClasses and the objects reclaimed in the GC. Make sure that's actually
 140   // true.
 141   if (kIsDebugBuild) {
 142     CheckNoDexObjects();
 143   }
 144
 145   if (kIsDebugBuild) {
 146     ScopedObjectAccess soa(Thread::Current());
 147     CheckNonImageClassesRemoved();
 148   }
 149
 150   {
 151     ScopedObjectAccess soa(Thread::Current());
 152     CalculateNewObjectOffsets();
 153   }
 154
 155   // This needs to happen after CalculateNewObjectOffsets since it relies on intern_table_bytes_ and
 156   // bin size sums being calculated.
 157   if (!AllocMemory()) {
 158     return false;
 159   }
 160
 161   return true;
 162 }
 163
 164 bool ImageWriter::Write(int image_fd,
 165                         const std::vector<const char*>& image_filenames,
 166                         const std::vector<const char*>& oat_filenames) {
 167   // If image_fd or oat_fd are not kInvalidFd then we may have empty strings in image_filenames or
 168   // oat_filenames.
 169   CHECK(!image_filenames.empty());
 170   if (image_fd != kInvalidFd) {
 171     CHECK_EQ(image_filenames.size(), 1u);
 172   }
 173   CHECK(!oat_filenames.empty());
 174   CHECK_EQ(image_filenames.size(), oat_filenames.size());
 175
 176   {
 177     ScopedObjectAccess soa(Thread::Current());
 178     for (size_t i = 0; i < oat_filenames.size(); ++i) {
 179       CreateHeader(i);
 180       CopyAndFixupNativeData(i);
 181     }
 182   }
 183
 184   {
 185     // TODO: heap validation can't handle these fix up passes.
 186     ScopedObjectAccess soa(Thread::Current());
 187     Runtime::Current()->GetHeap()->DisableObjectValidation();
 188     CopyAndFixupObjects();
 189   }
 190
 191   for (size_t i = 0; i < image_filenames.size(); ++i) {
 192     const char* image_filename = image_filenames[i];
 193     ImageInfo& image_info = GetImageInfo(i);
 194     std::unique_ptr<File> image_file;
 195     if (image_fd != kInvalidFd) {
 196       if (strlen(image_filename) == 0u) {
 197         image_file.reset(new File(image_fd, unix_file::kCheckSafeUsage));
 198         // Empty the file in case it already exists.
 199         if (image_file != nullptr) {
 200           TEMP_FAILURE_RETRY(image_file->SetLength(0));
 201           TEMP_FAILURE_RETRY(image_file->Flush());
 202         }
 203       } else {
 204         LOG(ERROR) << "image fd " << image_fd << " name " << image_filename;
 205       }
 206     } else {
 207       image_file.reset(OS::CreateEmptyFile(image_filename));
 208     }
 209
 210     if (image_file == nullptr) {
 211       LOG(ERROR) << "Failed to open image file " << image_filename;
 212       return false;
 213     }
 214
 215     if (!compile_app_image_ && fchmod(image_file->Fd(), 0644) != 0) {
 216       PLOG(ERROR) << "Failed to make image file world readable: " << image_filename;
 217       image_file->Erase();
 218       return EXIT_FAILURE;
 219     }
 220
 221     std::unique_ptr<char[]> compressed_data;
 222     // Image data size excludes the bitmap and the header.
 223     ImageHeader* const image_header = reinterpret_cast<ImageHeader*>(image_info.image_->Begin());
 224     const size_t image_data_size = image_header->GetImageSize() - sizeof(ImageHeader);
 225     char* image_data = reinterpret_cast<char*>(image_info.image_->Begin()) + sizeof(ImageHeader);
 226     size_t data_size;
 227     const char* image_data_to_write;
 228     const uint64_t compress_start_time = NanoTime();
 229
 230     CHECK_EQ(image_header->storage_mode_, image_storage_mode_);
 231     switch (image_storage_mode_) {
 232       case ImageHeader::kStorageModeLZ4HC:  // Fall-through.
 233       case ImageHeader::kStorageModeLZ4: {
 234         const size_t compressed_max_size = LZ4_compressBound(image_data_size);
 235         compressed_data.reset(new char[compressed_max_size]);
 236         data_size = LZ4_compress(
 237             reinterpret_cast<char*>(image_info.image_->Begin()) + sizeof(ImageHeader),
 238             &compressed_data[0],
 239             image_data_size);
 240
 241         break;
 242       }
 243       /*
 244        * Disabled due to image_test64 flakyness. Both use same decompression. b/27560444
 245       case ImageHeader::kStorageModeLZ4HC: {
 246         // Bound is same as non HC.
 247         const size_t compressed_max_size = LZ4_compressBound(image_data_size);
 248         compressed_data.reset(new char[compressed_max_size]);
 249         data_size = LZ4_compressHC(
 250             reinterpret_cast<char*>(image_info.image_->Begin()) + sizeof(ImageHeader),
 251             &compressed_data[0],
 252             image_data_size);
 253         break;
 254       }
 255       */
 256       case ImageHeader::kStorageModeUncompressed: {
 257         data_size = image_data_size;
 258         image_data_to_write = image_data;
 259         break;
 260       }
 261       default: {
 262         LOG(FATAL) << "Unsupported";
 263         UNREACHABLE();
 264       }
 265     }
 266
 267     if (compressed_data != nullptr) {
 268       image_data_to_write = &compressed_data[0];
 269       VLOG(compiler) << "Compressed from " << image_data_size << " to " << data_size << " in "
 270                      << PrettyDuration(NanoTime() - compress_start_time);
 271       if (kIsDebugBuild) {
 272         std::unique_ptr<uint8_t[]> temp(new uint8_t[image_data_size]);
 273         const size_t decompressed_size = LZ4_decompress_safe(
 274             reinterpret_cast<char*>(&compressed_data[0]),
 275             reinterpret_cast<char*>(&temp[0]),
 276             data_size,
 277             image_data_size);
 278         CHECK_EQ(decompressed_size, image_data_size);
 279         CHECK_EQ(memcmp(image_data, &temp[0], image_data_size), 0) << image_storage_mode_;
 280       }
 281     }
 282
 283     // Write out the image + fields + methods.
 284     const bool is_compressed = compressed_data != nullptr;
 285     if (!image_file->PwriteFully(image_data_to_write, data_size, sizeof(ImageHeader))) {
 286       PLOG(ERROR) << "Failed to write image file data " << image_filename;
 287       image_file->Erase();
 288       return false;
 289     }
 290
 291     // Write out the image bitmap at the page aligned start of the image end, also uncompressed for
 292     // convenience.
 293     const ImageSection& bitmap_section = image_header->GetImageSection(
 294         ImageHeader::kSectionImageBitmap);
 295     // Align up since data size may be unaligned if the image is compressed.
 296     size_t bitmap_position_in_file = RoundUp(sizeof(ImageHeader) + data_size, kPageSize);
 297     if (!is_compressed) {
 298       CHECK_EQ(bitmap_position_in_file, bitmap_section.Offset());
 299     }
 300     if (!image_file->PwriteFully(reinterpret_cast<char*>(image_info.image_bitmap_->Begin()),
 301                                  bitmap_section.Size(),
 302                                  bitmap_position_in_file)) {
 303       PLOG(ERROR) << "Failed to write image file " << image_filename;
 304       image_file->Erase();
 305       return false;
 306     }
 307
 308     int err = image_file->Flush();
 309     if (err < 0) {
 310       PLOG(ERROR) << "Failed to flush image file " << image_filename << " with result " << err;
 311       image_file->Erase();
 312       return false;
 313     }
 314
 315     // Write header last in case the compiler gets killed in the middle of image writing.
 316     // We do not want to have a corrupted image with a valid header.
 317     // The header is uncompressed since it contains whether the image is compressed or not.
 318     image_header->data_size_ = data_size;
 319     if (!image_file->PwriteFully(reinterpret_cast<char*>(image_info.image_->Begin()),
 320                                  sizeof(ImageHeader),
 321                                  0)) {
 322       PLOG(ERROR) << "Failed to write image file header " << image_filename;
 323       image_file->Erase();
 324       return false;
 325     }
 326
 327     CHECK_EQ(bitmap_position_in_file + bitmap_section.Size(),
 328              static_cast<size_t>(image_file->GetLength()));
 329     if (image_file->FlushCloseOrErase() != 0) {
 330       PLOG(ERROR) << "Failed to flush and close image file " << image_filename;
 331       return false;
 332     }
 333   }
 334   return true;
 335 }
 336
 337 void ImageWriter::SetImageOffset(mirror::Object* object, size_t offset) {
 338   DCHECK(object != nullptr);
 339   DCHECK_NE(offset, 0U);
 340
 341   // The object is already deflated from when we set the bin slot. Just overwrite the lock word.
 342   object->SetLockWord(LockWord::FromForwardingAddress(offset), false);
 343   DCHECK_EQ(object->GetLockWord(false).ReadBarrierState(), 0u);
 344   DCHECK(IsImageOffsetAssigned(object));
 345 }
 346
 347 void ImageWriter::UpdateImageOffset(mirror::Object* obj, uintptr_t offset) {
 348   DCHECK(IsImageOffsetAssigned(obj)) << obj << " " << offset;
 349   obj->SetLockWord(LockWord::FromForwardingAddress(offset), false);
 350   DCHECK_EQ(obj->GetLockWord(false).ReadBarrierState(), 0u);
 351 }
 352
 353 void ImageWriter::AssignImageOffset(mirror::Object* object, ImageWriter::BinSlot bin_slot) {
 354   DCHECK(object != nullptr);
 355   DCHECK_NE(image_objects_offset_begin_, 0u);
 356
 357   size_t oat_index = GetOatIndex(object);
 358   ImageInfo& image_info = GetImageInfo(oat_index);
 359   size_t bin_slot_offset = image_info.bin_slot_offsets_[bin_slot.GetBin()];
 360   size_t new_offset = bin_slot_offset + bin_slot.GetIndex();
 361   DCHECK_ALIGNED(new_offset, kObjectAlignment);
 362
 363   SetImageOffset(object, new_offset);
 364   DCHECK_LT(new_offset, image_info.image_end_);
 365 }
 366
 367 bool ImageWriter::IsImageOffsetAssigned(mirror::Object* object) const {
 368   // Will also return true if the bin slot was assigned since we are reusing the lock word.
 369   DCHECK(object != nullptr);
 370   return object->GetLockWord(false).GetState() == LockWord::kForwardingAddress;
 371 }
 372
 373 size_t ImageWriter::GetImageOffset(mirror::Object* object) const {
 374   DCHECK(object != nullptr);
 375   DCHECK(IsImageOffsetAssigned(object));
 376   LockWord lock_word = object->GetLockWord(false);
 377   size_t offset = lock_word.ForwardingAddress();
 378   size_t oat_index = GetOatIndex(object);
 379   const ImageInfo& image_info = GetImageInfo(oat_index);
 380   DCHECK_LT(offset, image_info.image_end_);
 381   return offset;
 382 }
 383
 384 void ImageWriter::SetImageBinSlot(mirror::Object* object, BinSlot bin_slot) {
 385   DCHECK(object != nullptr);
 386   DCHECK(!IsImageOffsetAssigned(object));
 387   DCHECK(!IsImageBinSlotAssigned(object));
 388
 389   // Before we stomp over the lock word, save the hash code for later.
 390   Monitor::Deflate(Thread::Current(), object);;
 391   LockWord lw(object->GetLockWord(false));
 392   switch (lw.GetState()) {
 393     case LockWord::kFatLocked: {
 394       LOG(FATAL) << "Fat locked object " << object << " found during object copy";
 395       break;
 396     }
 397     case LockWord::kThinLocked: {
 398       LOG(FATAL) << "Thin locked object " << object << " found during object copy";
 399       break;
 400     }
 401     case LockWord::kUnlocked:
 402       // No hash, don't need to save it.
 403       break;
 404     case LockWord::kHashCode:
 405       DCHECK(saved_hashcode_map_.find(object) == saved_hashcode_map_.end());
 406       saved_hashcode_map_.emplace(object, lw.GetHashCode());
 407       break;
 408     default:
 409       LOG(FATAL) << "Unreachable.";
 410       UNREACHABLE();
 411   }
 412   object->SetLockWord(LockWord::FromForwardingAddress(bin_slot.Uint32Value()), false);
 413   DCHECK_EQ(object->GetLockWord(false).ReadBarrierState(), 0u);
 414   DCHECK(IsImageBinSlotAssigned(object));
 415 }
 416
 417 void ImageWriter::PrepareDexCacheArraySlots() {
 418   // Prepare dex cache array starts based on the ordering specified in the CompilerDriver.
 419   // Set the slot size early to avoid DCHECK() failures in IsImageBinSlotAssigned()
 420   // when AssignImageBinSlot() assigns their indexes out or order.
 421   for (const DexFile* dex_file : compiler_driver_.GetDexFilesForOatFile()) {
 422     auto it = dex_file_oat_index_map_.find(dex_file);
 423     DCHECK(it != dex_file_oat_index_map_.end()) << dex_file->GetLocation();
 424     ImageInfo& image_info = GetImageInfo(it->second);
 425     image_info.dex_cache_array_starts_.Put(dex_file, image_info.bin_slot_sizes_[kBinDexCacheArray]);
 426     DexCacheArraysLayout layout(target_ptr_size_, dex_file);
 427     image_info.bin_slot_sizes_[kBinDexCacheArray] += layout.Size();
 428   }
 429
 430   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
 431   Thread* const self = Thread::Current();
 432   ReaderMutexLock mu(self, *class_linker->DexLock());
 433   for (const ClassLinker::DexCacheData& data : class_linker->GetDexCachesData()) {
 434     mirror::DexCache* dex_cache =
 435         down_cast<mirror::DexCache*>(self->DecodeJObject(data.weak_root));
 436     if (dex_cache == nullptr || IsInBootImage(dex_cache)) {
 437       continue;
 438     }
 439     const DexFile* dex_file = dex_cache->GetDexFile();
 440     DexCacheArraysLayout layout(target_ptr_size_, dex_file);
 441     DCHECK(layout.Valid());
 442     size_t oat_index = GetOatIndexForDexCache(dex_cache);
 443     ImageInfo& image_info = GetImageInfo(oat_index);
 444     uint32_t start = image_info.dex_cache_array_starts_.Get(dex_file);
 445     DCHECK_EQ(dex_file->NumTypeIds() != 0u, dex_cache->GetResolvedTypes() != nullptr);
 446     AddDexCacheArrayRelocation(dex_cache->GetResolvedTypes(),
 447                                start + layout.TypesOffset(),
 448                                dex_cache);
 449     DCHECK_EQ(dex_file->NumMethodIds() != 0u, dex_cache->GetResolvedMethods() != nullptr);
 450     AddDexCacheArrayRelocation(dex_cache->GetResolvedMethods(),
 451                                start + layout.MethodsOffset(),
 452                                dex_cache);
 453     DCHECK_EQ(dex_file->NumFieldIds() != 0u, dex_cache->GetResolvedFields() != nullptr);
 454     AddDexCacheArrayRelocation(dex_cache->GetResolvedFields(),
 455                                start + layout.FieldsOffset(),
 456                                dex_cache);
 457     DCHECK_EQ(dex_file->NumStringIds() != 0u, dex_cache->GetStrings() != nullptr);
 458     AddDexCacheArrayRelocation(dex_cache->GetStrings(), start + layout.StringsOffset(), dex_cache);
 459   }
 460 }
 461
 462 void ImageWriter::AddDexCacheArrayRelocation(void* array, size_t offset, DexCache* dex_cache) {
 463   if (array != nullptr) {
 464     DCHECK(!IsInBootImage(array));
 465     size_t oat_index = GetOatIndexForDexCache(dex_cache);
 466     native_object_relocations_.emplace(array,
 467         NativeObjectRelocation { oat_index, offset, kNativeObjectRelocationTypeDexCacheArray });
 468   }
 469 }
 470
 471 void ImageWriter::AddMethodPointerArray(mirror::PointerArray* arr) {
 472   DCHECK(arr != nullptr);
 473   if (kIsDebugBuild) {
 474     for (size_t i = 0, len = arr->GetLength(); i < len; i++) {
 475       ArtMethod* method = arr->GetElementPtrSize<ArtMethod*>(i, target_ptr_size_);
 476       if (method != nullptr && !method->IsRuntimeMethod()) {
 477         mirror::Class* klass = method->GetDeclaringClass();
 478         CHECK(klass == nullptr || KeepClass(klass))
 479             << PrettyClass(klass) << " should be a kept class";
 480       }
 481     }
 482   }
 483   // kBinArtMethodClean picked arbitrarily, just required to differentiate between ArtFields and
 484   // ArtMethods.
 485   pointer_arrays_.emplace(arr, kBinArtMethodClean);
 486 }
 487
 488 void ImageWriter::AssignImageBinSlot(mirror::Object* object) {
 489   DCHECK(object != nullptr);
 490   size_t object_size = object->SizeOf();
 491
 492   // The magic happens here. We segregate objects into different bins based
 493   // on how likely they are to get dirty at runtime.
 494   //
 495   // Likely-to-dirty objects get packed together into the same bin so that
 496   // at runtime their page dirtiness ratio (how many dirty objects a page has) is
 497   // maximized.
 498   //
 499   // This means more pages will stay either clean or shared dirty (with zygote) and
 500   // the app will use less of its own (private) memory.
 501   Bin bin = kBinRegular;
 502   size_t current_offset = 0u;
 503
 504   if (kBinObjects) {
 505     //
 506     // Changing the bin of an object is purely a memory-use tuning.
 507     // It has no change on runtime correctness.
 508     //
 509     // Memory analysis has determined that the following types of objects get dirtied
 510     // the most:
 511     //
 512     // * Dex cache arrays are stored in a special bin. The arrays for each dex cache have
 513     //   a fixed layout which helps improve generated code (using PC-relative addressing),
 514     //   so we pre-calculate their offsets separately in PrepareDexCacheArraySlots().
 515     //   Since these arrays are huge, most pages do not overlap other objects and it's not
 516     //   really important where they are for the clean/dirty separation. Due to their
 517     //   special PC-relative addressing, we arbitrarily keep them at the end.
 518     // * Class'es which are verified [their clinit runs only at runtime]
 519     //   - classes in general [because their static fields get overwritten]
 520     //   - initialized classes with all-final statics are unlikely to be ever dirty,
 521     //     so bin them separately
 522     // * Art Methods that are:
 523     //   - native [their native entry point is not looked up until runtime]
 524     //   - have declaring classes that aren't initialized
 525     //            [their interpreter/quick entry points are trampolines until the class
 526     //             becomes initialized]
 527     //
 528     // We also assume the following objects get dirtied either never or extremely rarely:
 529     //  * Strings (they are immutable)
 530     //  * Art methods that aren't native and have initialized declared classes
 531     //
 532     // We assume that "regular" bin objects are highly unlikely to become dirtied,
 533     // so packing them together will not result in a noticeably tighter dirty-to-clean ratio.
 534     //
 535     if (object->IsClass()) {
 536       bin = kBinClassVerified;
 537       mirror::Class* klass = object->AsClass();
 538
 539       // Add non-embedded vtable to the pointer array table if there is one.
 540       auto* vtable = klass->GetVTable();
 541       if (vtable != nullptr) {
 542         AddMethodPointerArray(vtable);
 543       }
 544       auto* iftable = klass->GetIfTable();
 545       if (iftable != nullptr) {
 546         for (int32_t i = 0; i < klass->GetIfTableCount(); ++i) {
 547           if (iftable->GetMethodArrayCount(i) > 0) {
 548             AddMethodPointerArray(iftable->GetMethodArray(i));
 549           }
 550         }
 551       }
 552
 553       if (klass->GetStatus() == Class::kStatusInitialized) {
 554         bin = kBinClassInitialized;
 555
 556         // If the class's static fields are all final, put it into a separate bin
 557         // since it's very likely it will stay clean.
 558         uint32_t num_static_fields = klass->NumStaticFields();
 559         if (num_static_fields == 0) {
 560           bin = kBinClassInitializedFinalStatics;
 561         } else {
 562           // Maybe all the statics are final?
 563           bool all_final = true;
 564           for (uint32_t i = 0; i < num_static_fields; ++i) {
 565             ArtField* field = klass->GetStaticField(i);
 566             if (!field->IsFinal()) {
 567               all_final = false;
 568               break;
 569             }
 570           }
 571
 572           if (all_final) {
 573             bin = kBinClassInitializedFinalStatics;
 574           }
 575         }
 576       }
 577     } else if (object->GetClass<kVerifyNone>()->IsStringClass()) {
 578       bin = kBinString;  // Strings are almost always immutable (except for object header).
 579     } else if (object->GetClass<kVerifyNone>() ==
 580         Runtime::Current()->GetClassLinker()->GetClassRoot(ClassLinker::kJavaLangObject)) {
 581       // Instance of java lang object, probably a lock object. This means it will be dirty when we
 582       // synchronize on it.
 583       bin = kBinMiscDirty;
 584     } else if (object->IsDexCache()) {
 585       // Dex file field becomes dirty when the image is loaded.
 586       bin = kBinMiscDirty;
 587     }
 588     // else bin = kBinRegular
 589   }
 590
 591   size_t oat_index = GetOatIndex(object);
 592   ImageInfo& image_info = GetImageInfo(oat_index);
 593
 594   size_t offset_delta = RoundUp(object_size, kObjectAlignment);  // 64-bit alignment
 595   current_offset = image_info.bin_slot_sizes_[bin];  // How many bytes the current bin is at (aligned).
 596   // Move the current bin size up to accommodate the object we just assigned a bin slot.
 597   image_info.bin_slot_sizes_[bin] += offset_delta;
 598
 599   BinSlot new_bin_slot(bin, current_offset);
 600   SetImageBinSlot(object, new_bin_slot);
 601
 602   ++image_info.bin_slot_count_[bin];
 603
 604   // Grow the image closer to the end by the object we just assigned.
 605   image_info.image_end_ += offset_delta;
 606 }
 607
 608 bool ImageWriter::WillMethodBeDirty(ArtMethod* m) const {
 609   if (m->IsNative()) {
 610     return true;
 611   }
 612   mirror::Class* declaring_class = m->GetDeclaringClass();
 613   // Initialized is highly unlikely to dirty since there's no entry points to mutate.
 614   return declaring_class == nullptr || declaring_class->GetStatus() != Class::kStatusInitialized;
 615 }
 616
 617 bool ImageWriter::IsImageBinSlotAssigned(mirror::Object* object) const {
 618   DCHECK(object != nullptr);
 619
 620   // We always stash the bin slot into a lockword, in the 'forwarding address' state.
 621   // If it's in some other state, then we haven't yet assigned an image bin slot.
 622   if (object->GetLockWord(false).GetState() != LockWord::kForwardingAddress) {
 623     return false;
 624   } else if (kIsDebugBuild) {
 625     LockWord lock_word = object->GetLockWord(false);
 626     size_t offset = lock_word.ForwardingAddress();
 627     BinSlot bin_slot(offset);
 628     size_t oat_index = GetOatIndex(object);
 629     const ImageInfo& image_info = GetImageInfo(oat_index);
 630     DCHECK_LT(bin_slot.GetIndex(), image_info.bin_slot_sizes_[bin_slot.GetBin()])
 631         << "bin slot offset should not exceed the size of that bin";
 632   }
 633   return true;
 634 }
 635
 636 ImageWriter::BinSlot ImageWriter::GetImageBinSlot(mirror::Object* object) const {
 637   DCHECK(object != nullptr);
 638   DCHECK(IsImageBinSlotAssigned(object));
 639
 640   LockWord lock_word = object->GetLockWord(false);
 641   size_t offset = lock_word.ForwardingAddress();  // TODO: ForwardingAddress should be uint32_t
 642   DCHECK_LE(offset, std::numeric_limits<uint32_t>::max());
 643
 644   BinSlot bin_slot(static_cast<uint32_t>(offset));
 645   size_t oat_index = GetOatIndex(object);
 646   const ImageInfo& image_info = GetImageInfo(oat_index);
 647   DCHECK_LT(bin_slot.GetIndex(), image_info.bin_slot_sizes_[bin_slot.GetBin()]);
 648
 649   return bin_slot;
 650 }
 651
 652 bool ImageWriter::AllocMemory() {
 653   for (ImageInfo& image_info : image_infos_) {
 654     ImageSection unused_sections[ImageHeader::kSectionCount];
 655     const size_t length = RoundUp(
 656         image_info.CreateImageSections(unused_sections), kPageSize);
 657
 658     std::string error_msg;
 659     image_info.image_.reset(MemMap::MapAnonymous("image writer image",
 660                                                  nullptr,
 661                                                  length,
 662                                                  PROT_READ | PROT_WRITE,
 663                                                  false,
 664                                                  false,
 665                                                  &error_msg));
 666     if (UNLIKELY(image_info.image_.get() == nullptr)) {
 667       LOG(ERROR) << "Failed to allocate memory for image file generation: " << error_msg;
 668       return false;
 669     }
 670
 671     // Create the image bitmap, only needs to cover mirror object section which is up to image_end_.
 672     CHECK_LE(image_info.image_end_, length);
 673     image_info.image_bitmap_.reset(gc::accounting::ContinuousSpaceBitmap::Create(
 674         "image bitmap", image_info.image_->Begin(), RoundUp(image_info.image_end_, kPageSize)));
 675     if (image_info.image_bitmap_.get() == nullptr) {
 676       LOG(ERROR) << "Failed to allocate memory for image bitmap";
 677       return false;
 678     }
 679   }
 680   return true;
 681 }
 682
 683 class ComputeLazyFieldsForClassesVisitor : public ClassVisitor {
 684  public:
 685   bool operator()(Class* c) OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
 686     StackHandleScope<1> hs(Thread::Current());
 687     mirror::Class::ComputeName(hs.NewHandle(c));
 688     return true;
 689   }
 690 };
 691
 692 void ImageWriter::ComputeLazyFieldsForImageClasses() {
 693   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
 694   ComputeLazyFieldsForClassesVisitor visitor;
 695   class_linker->VisitClassesWithoutClassesLock(&visitor);
 696 }
 697
 698 static bool IsBootClassLoaderClass(mirror::Class* klass) SHARED_REQUIRES(Locks::mutator_lock_) {
 699   return klass->GetClassLoader() == nullptr;
 700 }
 701
 702 bool ImageWriter::IsBootClassLoaderNonImageClass(mirror::Class* klass) {
 703   return IsBootClassLoaderClass(klass) && !IsInBootImage(klass);
 704 }
 705
 706 bool ImageWriter::PruneAppImageClass(mirror::Class* klass) {
 707   bool early_exit = false;
 708   std::unordered_set<mirror::Class*> visited;
 709   return PruneAppImageClassInternal(klass, &early_exit, &visited);
 710 }
 711
 712 bool ImageWriter::PruneAppImageClassInternal(
 713     mirror::Class* klass,
 714     bool* early_exit,
 715     std::unordered_set<mirror::Class*>* visited) {
 716   DCHECK(early_exit != nullptr);
 717   DCHECK(visited != nullptr);
 718   DCHECK(compile_app_image_);
 719   if (klass == nullptr || IsInBootImage(klass)) {
 720     return false;
 721   }
 722   auto found = prune_class_memo_.find(klass);
 723   if (found != prune_class_memo_.end()) {
 724     // Already computed, return the found value.
 725     return found->second;
 726   }
 727   // Circular dependencies, return false but do not store the result in the memoization table.
 728   if (visited->find(klass) != visited->end()) {
 729     *early_exit = true;
 730     return false;
 731   }
 732   visited->emplace(klass);
 733   bool result = IsBootClassLoaderClass(klass);
 734   std::string temp;
 735   // Prune if not an image class, this handles any broken sets of image classes such as having a
 736   // class in the set but not it's superclass.
 737   result = result || !compiler_driver_.IsImageClass(klass->GetDescriptor(&temp));
 738   bool my_early_exit = false;  // Only for ourselves, ignore caller.
 739   // Remove classes that failed to verify since we don't want to have java.lang.VerifyError in the
 740   // app image.
 741   if (klass->GetStatus() == mirror::Class::kStatusError) {
 742     result = true;
 743   } else {
 744     CHECK(klass->GetVerifyError() == nullptr) << PrettyClass(klass);
 745   }
 746   if (!result) {
 747     // Check interfaces since these wont be visited through VisitReferences.)
 748     mirror::IfTable* if_table = klass->GetIfTable();
 749     for (size_t i = 0, num_interfaces = klass->GetIfTableCount(); i < num_interfaces; ++i) {
 750       result = result || PruneAppImageClassInternal(if_table->GetInterface(i),
 751                                                     &my_early_exit,
 752                                                     visited);
 753     }
 754   }
 755   if (klass->IsObjectArrayClass()) {
 756     result = result || PruneAppImageClassInternal(klass->GetComponentType(),
 757                                                   &my_early_exit,
 758                                                   visited);
 759   }
 760   // Check static fields and their classes.
 761   size_t num_static_fields = klass->NumReferenceStaticFields();
 762   if (num_static_fields != 0 && klass->IsResolved()) {
 763     // Presumably GC can happen when we are cross compiling, it should not cause performance
 764     // problems to do pointer size logic.
 765     MemberOffset field_offset = klass->GetFirstReferenceStaticFieldOffset(
 766         Runtime::Current()->GetClassLinker()->GetImagePointerSize());
 767     for (size_t i = 0u; i < num_static_fields; ++i) {
 768       mirror::Object* ref = klass->GetFieldObject<mirror::Object>(field_offset);
 769       if (ref != nullptr) {
 770         if (ref->IsClass()) {
 771           result = result || PruneAppImageClassInternal(ref->AsClass(),
 772                                                         &my_early_exit,
 773                                                         visited);
 774         } else {
 775           result = result || PruneAppImageClassInternal(ref->GetClass(),
 776                                                         &my_early_exit,
 777                                                         visited);
 778         }
 779       }
 780       field_offset = MemberOffset(field_offset.Uint32Value() +
 781                                   sizeof(mirror::HeapReference<mirror::Object>));
 782     }
 783   }
 784   result = result || PruneAppImageClassInternal(klass->GetSuperClass(),
 785                                                 &my_early_exit,
 786                                                 visited);
 787   // Erase the element we stored earlier since we are exiting the function.
 788   auto it = visited->find(klass);
 789   DCHECK(it != visited->end());
 790   visited->erase(it);
 791   // Only store result if it is true or none of the calls early exited due to circular
 792   // dependencies. If visited is empty then we are the root caller, in this case the cycle was in
 793   // a child call and we can remember the result.
 794   if (result == true || !my_early_exit || visited->empty()) {
 795     prune_class_memo_[klass] = result;
 796   }
 797   *early_exit |= my_early_exit;
 798   return result;
 799 }
 800
 801 bool ImageWriter::KeepClass(Class* klass) {
 802   if (klass == nullptr) {
 803     return false;
 804   }
 805   if (compile_app_image_ && Runtime::Current()->GetHeap()->ObjectIsInBootImageSpace(klass)) {
 806     // Already in boot image, return true.
 807     return true;
 808   }
 809   std::string temp;
 810   if (!compiler_driver_.IsImageClass(klass->GetDescriptor(&temp))) {
 811     return false;
 812   }
 813   if (compile_app_image_) {
 814     // For app images, we need to prune boot loader classes that are not in the boot image since
 815     // these may have already been loaded when the app image is loaded.
 816     // Keep classes in the boot image space since we don't want to re-resolve these.
 817     return !PruneAppImageClass(klass);
 818   }
 819   return true;
 820 }
 821
 822 class NonImageClassesVisitor : public ClassVisitor {
 823  public:
 824   explicit NonImageClassesVisitor(ImageWriter* image_writer) : image_writer_(image_writer) {}
 825
 826   bool operator()(Class* klass) OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
 827     if (!image_writer_->KeepClass(klass)) {
 828       classes_to_prune_.insert(klass);
 829     }
 830     return true;
 831   }
 832
 833   std::unordered_set<mirror::Class*> classes_to_prune_;
 834   ImageWriter* const image_writer_;
 835 };
 836
 837 void ImageWriter::PruneNonImageClasses() {
 838   Runtime* runtime = Runtime::Current();
 839   ClassLinker* class_linker = runtime->GetClassLinker();
 840   Thread* self = Thread::Current();
 841
 842   // Make a list of classes we would like to prune.
 843   NonImageClassesVisitor visitor(this);
 844   class_linker->VisitClasses(&visitor);
 845
 846   // Remove the undesired classes from the class roots.
 847   VLOG(compiler) << "Pruning " << visitor.classes_to_prune_.size() << " classes";
 848   for (mirror::Class* klass : visitor.classes_to_prune_) {
 849     std::string temp;
 850     const char* name = klass->GetDescriptor(&temp);
 851     VLOG(compiler) << "Pruning class " << name;
 852     if (!compile_app_image_) {
 853       DCHECK(IsBootClassLoaderClass(klass));
 854     }
 855     bool result = class_linker->RemoveClass(name, klass->GetClassLoader());
 856     DCHECK(result);
 857   }
 858
 859   // Clear references to removed classes from the DexCaches.
 860   ArtMethod* resolution_method = runtime->GetResolutionMethod();
 861
 862   ScopedAssertNoThreadSuspension sa(self, __FUNCTION__);
 863   ReaderMutexLock mu(self, *Locks::classlinker_classes_lock_);  // For ClassInClassTable
 864   ReaderMutexLock mu2(self, *class_linker->DexLock());
 865   for (const ClassLinker::DexCacheData& data : class_linker->GetDexCachesData()) {
 866     if (self->IsJWeakCleared(data.weak_root)) {
 867       continue;
 868     }
 869     mirror::DexCache* dex_cache = self->DecodeJObject(data.weak_root)->AsDexCache();
 870     for (size_t i = 0; i < dex_cache->NumResolvedTypes(); i++) {
 871       Class* klass = dex_cache->GetResolvedType(i);
 872       if (klass != nullptr && !KeepClass(klass)) {
 873         dex_cache->SetResolvedType(i, nullptr);
 874       }
 875     }
 876     ArtMethod** resolved_methods = dex_cache->GetResolvedMethods();
 877     for (size_t i = 0, num = dex_cache->NumResolvedMethods(); i != num; ++i) {
 878       ArtMethod* method =
 879           mirror::DexCache::GetElementPtrSize(resolved_methods, i, target_ptr_size_);
 880       DCHECK(method != nullptr) << "Expected resolution method instead of null method";
 881       mirror::Class* declaring_class = method->GetDeclaringClass();
 882       // Copied methods may be held live by a class which was not an image class but have a
 883       // declaring class which is an image class. Set it to the resolution method to be safe and
 884       // prevent dangling pointers.
 885       if (method->IsCopied() || !KeepClass(declaring_class)) {
 886         mirror::DexCache::SetElementPtrSize(resolved_methods,
 887                                             i,
 888                                             resolution_method,
 889                                             target_ptr_size_);
 890       } else {
 891         // Check that the class is still in the classes table.
 892         DCHECK(class_linker->ClassInClassTable(declaring_class)) << "Class "
 893             << PrettyClass(declaring_class) << " not in class linker table";
 894       }
 895     }
 896     ArtField** resolved_fields = dex_cache->GetResolvedFields();
 897     for (size_t i = 0; i < dex_cache->NumResolvedFields(); i++) {
 898       ArtField* field = mirror::DexCache::GetElementPtrSize(resolved_fields, i, target_ptr_size_);
 899       if (field != nullptr && !KeepClass(field->GetDeclaringClass())) {
 900         dex_cache->SetResolvedField(i, nullptr, target_ptr_size_);
 901       }
 902     }
 903     // Clean the dex field. It might have been populated during the initialization phase, but
 904     // contains data only valid during a real run.
 905     dex_cache->SetFieldObject<false>(mirror::DexCache::DexOffset(), nullptr);
 906   }
 907
 908   // Drop the array class cache in the ClassLinker, as these are roots holding those classes live.
 909   class_linker->DropFindArrayClassCache();
 910
 911   // Clear to save RAM.
 912   prune_class_memo_.clear();
 913 }
 914
 915 void ImageWriter::CheckNonImageClassesRemoved() {
 916   if (compiler_driver_.GetImageClasses() != nullptr) {
 917     gc::Heap* heap = Runtime::Current()->GetHeap();
 918     heap->VisitObjects(CheckNonImageClassesRemovedCallback, this);
 919   }
 920 }
 921
 922 void ImageWriter::CheckNonImageClassesRemovedCallback(Object* obj, void* arg) {
 923   ImageWriter* image_writer = reinterpret_cast<ImageWriter*>(arg);
 924   if (obj->IsClass() && !image_writer->IsInBootImage(obj)) {
 925     Class* klass = obj->AsClass();
 926     if (!image_writer->KeepClass(klass)) {
 927       image_writer->DumpImageClasses();
 928       std::string temp;
 929       CHECK(image_writer->KeepClass(klass)) << klass->GetDescriptor(&temp)
 930                                             << " " << PrettyDescriptor(klass);
 931     }
 932   }
 933 }
 934
 935 void ImageWriter::DumpImageClasses() {
 936   auto image_classes = compiler_driver_.GetImageClasses();
 937   CHECK(image_classes != nullptr);
 938   for (const std::string& image_class : *image_classes) {
 939     LOG(INFO) << " " << image_class;
 940   }
 941 }
 942
 943 mirror::String* ImageWriter::FindInternedString(mirror::String* string) {
 944   Thread* const self = Thread::Current();
 945   for (const ImageInfo& image_info : image_infos_) {
 946     mirror::String* const found = image_info.intern_table_->LookupStrong(self, string);
 947     DCHECK(image_info.intern_table_->LookupWeak(self, string) == nullptr)
 948         << string->ToModifiedUtf8();
 949     if (found != nullptr) {
 950       return found;
 951     }
 952   }
 953   if (compile_app_image_) {
 954     Runtime* const runtime = Runtime::Current();
 955     mirror::String* found = runtime->GetInternTable()->LookupStrong(self, string);
 956     // If we found it in the runtime intern table it could either be in the boot image or interned
 957     // during app image compilation. If it was in the boot image return that, otherwise return null
 958     // since it belongs to another image space.
 959     if (found != nullptr && runtime->GetHeap()->ObjectIsInBootImageSpace(found)) {
 960       return found;
 961     }
 962     DCHECK(runtime->GetInternTable()->LookupWeak(self, string) == nullptr)
 963         << string->ToModifiedUtf8();
 964   }
 965   return nullptr;
 966 }
 967
 968 void ImageWriter::CalculateObjectBinSlots(Object* obj) {
 969   DCHECK(obj != nullptr);
 970   // if it is a string, we want to intern it if its not interned.
 971   if (obj->GetClass()->IsStringClass()) {
 972     size_t oat_index = GetOatIndex(obj);
 973     ImageInfo& image_info = GetImageInfo(oat_index);
 974
 975     // we must be an interned string that was forward referenced and already assigned
 976     if (IsImageBinSlotAssigned(obj)) {
 977       DCHECK_EQ(obj, FindInternedString(obj->AsString()));
 978       return;
 979     }
 980     // Need to check if the string is already interned in another image info so that we don't have
 981     // the intern tables of two different images contain the same string.
 982     mirror::String* interned = FindInternedString(obj->AsString());
 983     if (interned == nullptr) {
 984       // Not in another image space, insert to our table.
 985       interned = image_info.intern_table_->InternStrongImageString(obj->AsString());
 986     }
 987     if (obj != interned) {
 988       if (!IsImageBinSlotAssigned(interned)) {
 989         // interned obj is after us, allocate its location early
 990         AssignImageBinSlot(interned);
 991       }
 992       // point those looking for this object to the interned version.
 993       SetImageBinSlot(obj, GetImageBinSlot(interned));
 994       return;
 995     }
 996     // else (obj == interned), nothing to do but fall through to the normal case
 997   }
 998
 999   AssignImageBinSlot(obj);
1000 }
1001
1002 ObjectArray<Object>* ImageWriter::CreateImageRoots(size_t oat_index) const {
1003   Runtime* runtime = Runtime::Current();
1004   ClassLinker* class_linker = runtime->GetClassLinker();
1005   Thread* self = Thread::Current();
1006   StackHandleScope<3> hs(self);
1007   Handle<Class> object_array_class(hs.NewHandle(
1008       class_linker->FindSystemClass(self, "[Ljava/lang/Object;")));
1009
1010   std::unordered_set<const DexFile*> image_dex_files;
1011   for (auto& pair : dex_file_oat_index_map_) {
1012     const DexFile* image_dex_file = pair.first;
1013     size_t image_oat_index = pair.second;
1014     if (oat_index == image_oat_index) {
1015       image_dex_files.insert(image_dex_file);
1016     }
1017   }
1018
1019   // build an Object[] of all the DexCaches used in the source_space_.
1020   // Since we can't hold the dex lock when allocating the dex_caches
1021   // ObjectArray, we lock the dex lock twice, first to get the number
1022   // of dex caches first and then lock it again to copy the dex
1023   // caches. We check that the number of dex caches does not change.
1024   size_t dex_cache_count = 0;
1025   {
1026     ReaderMutexLock mu(self, *class_linker->DexLock());
1027     // Count number of dex caches not in the boot image.
1028     for (const ClassLinker::DexCacheData& data : class_linker->GetDexCachesData()) {
1029       mirror::DexCache* dex_cache =
1030           down_cast<mirror::DexCache*>(self->DecodeJObject(data.weak_root));
1031       if (dex_cache == nullptr) {
1032         continue;
1033       }
1034       const DexFile* dex_file = dex_cache->GetDexFile();
1035       if (!IsInBootImage(dex_cache)) {
1036         dex_cache_count += image_dex_files.find(dex_file) != image_dex_files.end() ? 1u : 0u;
1037       }
1038     }
1039   }
1040   Handle<ObjectArray<Object>> dex_caches(
1041       hs.NewHandle(ObjectArray<Object>::Alloc(self, object_array_class.Get(), dex_cache_count)));
1042   CHECK(dex_caches.Get() != nullptr) << "Failed to allocate a dex cache array.";
1043   {
1044     ReaderMutexLock mu(self, *class_linker->DexLock());
1045     size_t non_image_dex_caches = 0;
1046     // Re-count number of non image dex caches.
1047     for (const ClassLinker::DexCacheData& data : class_linker->GetDexCachesData()) {
1048       mirror::DexCache* dex_cache =
1049           down_cast<mirror::DexCache*>(self->DecodeJObject(data.weak_root));
1050       if (dex_cache == nullptr) {
1051         continue;
1052       }
1053       const DexFile* dex_file = dex_cache->GetDexFile();
1054       if (!IsInBootImage(dex_cache)) {
1055         non_image_dex_caches += image_dex_files.find(dex_file) != image_dex_files.end() ? 1u : 0u;
1056       }
1057     }
1058     CHECK_EQ(dex_cache_count, non_image_dex_caches)
1059         << "The number of non-image dex caches changed.";
1060     size_t i = 0;
1061     for (const ClassLinker::DexCacheData& data : class_linker->GetDexCachesData()) {
1062       mirror::DexCache* dex_cache =
1063           down_cast<mirror::DexCache*>(self->DecodeJObject(data.weak_root));
1064       if (dex_cache == nullptr) {
1065         continue;
1066       }
1067       const DexFile* dex_file = dex_cache->GetDexFile();
1068       if (!IsInBootImage(dex_cache) && image_dex_files.find(dex_file) != image_dex_files.end()) {
1069         dex_caches->Set<false>(i, dex_cache);
1070         ++i;
1071       }
1072     }
1073   }
1074
1075   // build an Object[] of the roots needed to restore the runtime
1076   auto image_roots(hs.NewHandle(
1077       ObjectArray<Object>::Alloc(self, object_array_class.Get(), ImageHeader::kImageRootsMax)));
1078   image_roots->Set<false>(ImageHeader::kDexCaches, dex_caches.Get());
1079   image_roots->Set<false>(ImageHeader::kClassRoots, class_linker->GetClassRoots());
1080   for (int i = 0; i < ImageHeader::kImageRootsMax; i++) {
1081     CHECK(image_roots->Get(i) != nullptr);
1082   }
1083   return image_roots.Get();
1084 }
1085
1086 // Walk instance fields of the given Class. Separate function to allow recursion on the super
1087 // class.
1088 void ImageWriter::WalkInstanceFields(mirror::Object* obj, mirror::Class* klass) {
1089   // Visit fields of parent classes first.
1090   StackHandleScope<1> hs(Thread::Current());
1091   Handle<mirror::Class> h_class(hs.NewHandle(klass));
1092   mirror::Class* super = h_class->GetSuperClass();
1093   if (super != nullptr) {
1094     WalkInstanceFields(obj, super);
1095   }
1096   //
1097   size_t num_reference_fields = h_class->NumReferenceInstanceFields();
1098   MemberOffset field_offset = h_class->GetFirstReferenceInstanceFieldOffset();
1099   for (size_t i = 0; i < num_reference_fields; ++i) {
1100     mirror::Object* value = obj->GetFieldObject<mirror::Object>(field_offset);
1101     if (value != nullptr) {
1102       WalkFieldsInOrder(value);
1103     }
1104     field_offset = MemberOffset(field_offset.Uint32Value() +
1105                                 sizeof(mirror::HeapReference<mirror::Object>));
1106   }
1107 }
1108
1109 // For an unvisited object, visit it then all its children found via fields.
1110 void ImageWriter::WalkFieldsInOrder(mirror::Object* obj) {
1111   if (IsInBootImage(obj)) {
1112     // Object is in the image, don't need to fix it up.
1113     return;
1114   }
1115   // Use our own visitor routine (instead of GC visitor) to get better locality between
1116   // an object and its fields
1117   if (!IsImageBinSlotAssigned(obj)) {
1118     // Walk instance fields of all objects
1119     StackHandleScope<2> hs(Thread::Current());
1120     Handle<mirror::Object> h_obj(hs.NewHandle(obj));
1121     Handle<mirror::Class> klass(hs.NewHandle(obj->GetClass()));
1122     // visit the object itself.
1123     CalculateObjectBinSlots(h_obj.Get());
1124     WalkInstanceFields(h_obj.Get(), klass.Get());
1125     // Walk static fields of a Class.
1126     if (h_obj->IsClass()) {
1127       size_t num_reference_static_fields = klass->NumReferenceStaticFields();
1128       MemberOffset field_offset = klass->GetFirstReferenceStaticFieldOffset(target_ptr_size_);
1129       for (size_t i = 0; i < num_reference_static_fields; ++i) {
1130         mirror::Object* value = h_obj->GetFieldObject<mirror::Object>(field_offset);
1131         if (value != nullptr) {
1132           WalkFieldsInOrder(value);
1133         }
1134         field_offset = MemberOffset(field_offset.Uint32Value() +
1135                                     sizeof(mirror::HeapReference<mirror::Object>));
1136       }
1137       // Visit and assign offsets for fields and field arrays.
1138       auto* as_klass = h_obj->AsClass();
1139       mirror::DexCache* dex_cache = as_klass->GetDexCache();
1140       DCHECK_NE(klass->GetStatus(), mirror::Class::kStatusError);
1141       if (compile_app_image_) {
1142         // Extra sanity, no boot loader classes should be left!
1143         CHECK(!IsBootClassLoaderClass(as_klass)) << PrettyClass(as_klass);
1144       }
1145       LengthPrefixedArray<ArtField>* fields[] = {
1146           as_klass->GetSFieldsPtr(), as_klass->GetIFieldsPtr(),
1147       };
1148       size_t oat_index = GetOatIndexForDexCache(dex_cache);
1149       ImageInfo& image_info = GetImageInfo(oat_index);
1150       {
1151         // Note: This table is only accessed from the image writer, so the lock is technically
1152         // unnecessary.
1153         WriterMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
1154         // Insert in the class table for this iamge.
1155         image_info.class_table_->Insert(as_klass);
1156       }
1157       for (LengthPrefixedArray<ArtField>* cur_fields : fields) {
1158         // Total array length including header.
1159         if (cur_fields != nullptr) {
1160           const size_t header_size = LengthPrefixedArray<ArtField>::ComputeSize(0);
1161           // Forward the entire array at once.
1162           auto it = native_object_relocations_.find(cur_fields);
1163           CHECK(it == native_object_relocations_.end()) << "Field array " << cur_fields
1164                                                   << " already forwarded";
1165           size_t& offset = image_info.bin_slot_sizes_[kBinArtField];
1166           DCHECK(!IsInBootImage(cur_fields));
1167           native_object_relocations_.emplace(
1168               cur_fields,
1169               NativeObjectRelocation {
1170                   oat_index, offset, kNativeObjectRelocationTypeArtFieldArray
1171               });
1172           offset += header_size;
1173           // Forward individual fields so that we can quickly find where they belong.
1174           for (size_t i = 0, count = cur_fields->size(); i < count; ++i) {
1175             // Need to forward arrays separate of fields.
1176             ArtField* field = &cur_fields->At(i);
1177             auto it2 = native_object_relocations_.find(field);
1178             CHECK(it2 == native_object_relocations_.end()) << "Field at index=" << i
1179                 << " already assigned " << PrettyField(field) << " static=" << field->IsStatic();
1180             DCHECK(!IsInBootImage(field));
1181             native_object_relocations_.emplace(
1182                 field,
1183                 NativeObjectRelocation { oat_index, offset, kNativeObjectRelocationTypeArtField });
1184             offset += sizeof(ArtField);
1185           }
1186         }
1187       }
1188       // Visit and assign offsets for methods.
1189       size_t num_methods = as_klass->NumMethods();
1190       if (num_methods != 0) {
1191         bool any_dirty = false;
1192         for (auto& m : as_klass->GetMethods(target_ptr_size_)) {
1193           if (WillMethodBeDirty(&m)) {
1194             any_dirty = true;
1195             break;
1196           }
1197         }
1198         NativeObjectRelocationType type = any_dirty
1199             ? kNativeObjectRelocationTypeArtMethodDirty
1200             : kNativeObjectRelocationTypeArtMethodClean;
1201         Bin bin_type = BinTypeForNativeRelocationType(type);
1202         // Forward the entire array at once, but header first.
1203         const size_t method_alignment = ArtMethod::Alignment(target_ptr_size_);
1204         const size_t method_size = ArtMethod::Size(target_ptr_size_);
1205         const size_t header_size = LengthPrefixedArray<ArtMethod>::ComputeSize(0,
1206                                                                                method_size,
1207                                                                                method_alignment);
1208         LengthPrefixedArray<ArtMethod>* array = as_klass->GetMethodsPtr();
1209         auto it = native_object_relocations_.find(array);
1210         CHECK(it == native_object_relocations_.end())
1211             << "Method array " << array << " already forwarded";
1212         size_t& offset = image_info.bin_slot_sizes_[bin_type];
1213         DCHECK(!IsInBootImage(array));
1214         native_object_relocations_.emplace(array,
1215             NativeObjectRelocation {
1216                 oat_index,
1217                 offset,
1218                 any_dirty ? kNativeObjectRelocationTypeArtMethodArrayDirty
1219                           : kNativeObjectRelocationTypeArtMethodArrayClean });
1220         offset += header_size;
1221         for (auto& m : as_klass->GetMethods(target_ptr_size_)) {
1222           AssignMethodOffset(&m, type, oat_index);
1223         }
1224         (any_dirty ? dirty_methods_ : clean_methods_) += num_methods;
1225
1226         // Assign offsets for all runtime methods in the IMT since these may hold conflict tables
1227         // live.
1228         if (as_klass->ShouldHaveEmbeddedImtAndVTable()) {
1229           for (size_t i = 0; i < mirror::Class::kImtSize; ++i) {
1230             ArtMethod* imt_method = as_klass->GetEmbeddedImTableEntry(i, target_ptr_size_);
1231             DCHECK(imt_method != nullptr);
1232             if (imt_method->IsRuntimeMethod() &&
1233                 !IsInBootImage(imt_method) &&
1234                 !NativeRelocationAssigned(imt_method)) {
1235               AssignMethodOffset(imt_method, kNativeObjectRelocationTypeRuntimeMethod, oat_index);
1236             }
1237           }
1238         }
1239       }
1240     } else if (h_obj->IsObjectArray()) {
1241       // Walk elements of an object array.
1242       int32_t length = h_obj->AsObjectArray<mirror::Object>()->GetLength();
1243       for (int32_t i = 0; i < length; i++) {
1244         mirror::ObjectArray<mirror::Object>* obj_array = h_obj->AsObjectArray<mirror::Object>();
1245         mirror::Object* value = obj_array->Get(i);
1246         if (value != nullptr) {
1247           WalkFieldsInOrder(value);
1248         }
1249       }
1250     } else if (h_obj->IsClassLoader()) {
1251       // Register the class loader if it has a class table.
1252       // The fake boot class loader should not get registered and we should end up with only one
1253       // class loader.
1254       mirror::ClassLoader* class_loader = h_obj->AsClassLoader();
1255       if (class_loader->GetClassTable() != nullptr) {
1256         class_loaders_.insert(class_loader);
1257       }
1258     }
1259   }
1260 }
1261
1262 bool ImageWriter::NativeRelocationAssigned(void* ptr) const {
1263   return native_object_relocations_.find(ptr) != native_object_relocations_.end();
1264 }
1265
1266 void ImageWriter::TryAssignConflictTableOffset(ImtConflictTable* table, size_t oat_index) {
1267   // No offset, or already assigned.
1268   if (table == nullptr || NativeRelocationAssigned(table)) {
1269     return;
1270   }
1271   CHECK(!IsInBootImage(table));
1272   // If the method is a conflict method we also want to assign the conflict table offset.
1273   ImageInfo& image_info = GetImageInfo(oat_index);
1274   const size_t size = table->ComputeSize(target_ptr_size_);
1275   native_object_relocations_.emplace(
1276       table,
1277       NativeObjectRelocation {
1278           oat_index,
1279           image_info.bin_slot_sizes_[kBinIMTConflictTable],
1280           kNativeObjectRelocationTypeIMTConflictTable});
1281   image_info.bin_slot_sizes_[kBinIMTConflictTable] += size;
1282 }
1283
1284 void ImageWriter::AssignMethodOffset(ArtMethod* method,
1285                                      NativeObjectRelocationType type,
1286                                      size_t oat_index) {
1287   DCHECK(!IsInBootImage(method));
1288   CHECK(!NativeRelocationAssigned(method)) << "Method " << method << " already assigned "
1289       << PrettyMethod(method);
1290   if (method->IsRuntimeMethod()) {
1291     TryAssignConflictTableOffset(method->GetImtConflictTable(target_ptr_size_), oat_index);
1292   }
1293   ImageInfo& image_info = GetImageInfo(oat_index);
1294   size_t& offset = image_info.bin_slot_sizes_[BinTypeForNativeRelocationType(type)];
1295   native_object_relocations_.emplace(method, NativeObjectRelocation { oat_index, offset, type });
1296   offset += ArtMethod::Size(target_ptr_size_);
1297 }
1298
1299 void ImageWriter::WalkFieldsCallback(mirror::Object* obj, void* arg) {
1300   ImageWriter* writer = reinterpret_cast<ImageWriter*>(arg);
1301   DCHECK(writer != nullptr);
1302   writer->WalkFieldsInOrder(obj);
1303 }
1304
1305 void ImageWriter::UnbinObjectsIntoOffsetCallback(mirror::Object* obj, void* arg) {
1306   ImageWriter* writer = reinterpret_cast<ImageWriter*>(arg);
1307   DCHECK(writer != nullptr);
1308   if (!writer->IsInBootImage(obj)) {
1309     writer->UnbinObjectsIntoOffset(obj);
1310   }
1311 }
1312
1313 void ImageWriter::UnbinObjectsIntoOffset(mirror::Object* obj) {
1314   DCHECK(!IsInBootImage(obj));
1315   CHECK(obj != nullptr);
1316
1317   // We know the bin slot, and the total bin sizes for all objects by now,
1318   // so calculate the object's final image offset.
1319
1320   DCHECK(IsImageBinSlotAssigned(obj));
1321   BinSlot bin_slot = GetImageBinSlot(obj);
1322   // Change the lockword from a bin slot into an offset
1323   AssignImageOffset(obj, bin_slot);
1324 }
1325
1326 void ImageWriter::CalculateNewObjectOffsets() {
1327   Thread* const self = Thread::Current();
1328   StackHandleScopeCollection handles(self);
1329   std::vector<Handle<ObjectArray<Object>>> image_roots;
1330   for (size_t i = 0, size = oat_filenames_.size(); i != size; ++i) {
1331     image_roots.push_back(handles.NewHandle(CreateImageRoots(i)));
1332   }
1333
1334   auto* runtime = Runtime::Current();
1335   auto* heap = runtime->GetHeap();
1336
1337   // Leave space for the header, but do not write it yet, we need to
1338   // know where image_roots is going to end up
1339   image_objects_offset_begin_ = RoundUp(sizeof(ImageHeader), kObjectAlignment);  // 64-bit-alignment
1340
1341   const size_t method_alignment = ArtMethod::Alignment(target_ptr_size_);
1342   // Write the image runtime methods.
1343   image_methods_[ImageHeader::kResolutionMethod] = runtime->GetResolutionMethod();
1344   image_methods_[ImageHeader::kImtConflictMethod] = runtime->GetImtConflictMethod();
1345   image_methods_[ImageHeader::kImtUnimplementedMethod] = runtime->GetImtUnimplementedMethod();
1346   image_methods_[ImageHeader::kCalleeSaveMethod] = runtime->GetCalleeSaveMethod(Runtime::kSaveAll);
1347   image_methods_[ImageHeader::kRefsOnlySaveMethod] =
1348       runtime->GetCalleeSaveMethod(Runtime::kRefsOnly);
1349   image_methods_[ImageHeader::kRefsAndArgsSaveMethod] =
1350       runtime->GetCalleeSaveMethod(Runtime::kRefsAndArgs);
1351   // Visit image methods first to have the main runtime methods in the first image.
1352   for (auto* m : image_methods_) {
1353     CHECK(m != nullptr);
1354     CHECK(m->IsRuntimeMethod());
1355     DCHECK_EQ(compile_app_image_, IsInBootImage(m)) << "Trampolines should be in boot image";
1356     if (!IsInBootImage(m)) {
1357       AssignMethodOffset(m, kNativeObjectRelocationTypeRuntimeMethod, GetDefaultOatIndex());
1358     }
1359   }
1360
1361   // Clear any pre-existing monitors which may have been in the monitor words, assign bin slots.
1362   heap->VisitObjects(WalkFieldsCallback, this);
1363
1364   // Calculate size of the dex cache arrays slot and prepare offsets.
1365   PrepareDexCacheArraySlots();
1366
1367   // Calculate the sizes of the intern tables and class tables.
1368   for (ImageInfo& image_info : image_infos_) {
1369     // Calculate how big the intern table will be after being serialized.
1370     InternTable* const intern_table = image_info.intern_table_.get();
1371     CHECK_EQ(intern_table->WeakSize(), 0u) << " should have strong interned all the strings";
1372     image_info.intern_table_bytes_ = intern_table->WriteToMemory(nullptr);
1373     // Calculate the size of the class table.
1374     ReaderMutexLock mu(self, *Locks::classlinker_classes_lock_);
1375     image_info.class_table_bytes_ += image_info.class_table_->WriteToMemory(nullptr);
1376   }
1377
1378   // Calculate bin slot offsets.
1379   for (ImageInfo& image_info : image_infos_) {
1380     size_t bin_offset = image_objects_offset_begin_;
1381     for (size_t i = 0; i != kBinSize; ++i) {
1382       switch (i) {
1383         case kBinArtMethodClean:
1384         case kBinArtMethodDirty: {
1385           bin_offset = RoundUp(bin_offset, method_alignment);
1386           break;
1387         }
1388         case kBinIMTConflictTable: {
1389           bin_offset = RoundUp(bin_offset, target_ptr_size_);
1390           break;
1391         }
1392         default: {
1393           // Normal alignment.
1394         }
1395       }
1396       image_info.bin_slot_offsets_[i] = bin_offset;
1397       bin_offset += image_info.bin_slot_sizes_[i];
1398     }
1399     // NOTE: There may be additional padding between the bin slots and the intern table.
1400     DCHECK_EQ(image_info.image_end_,
1401               GetBinSizeSum(image_info, kBinMirrorCount) + image_objects_offset_begin_);
1402   }
1403
1404   // Calculate image offsets.
1405   size_t image_offset = 0;
1406   for (ImageInfo& image_info : image_infos_) {
1407     image_info.image_begin_ = global_image_begin_ + image_offset;
1408     image_info.image_offset_ = image_offset;
1409     ImageSection unused_sections[ImageHeader::kSectionCount];
1410     image_info.image_size_ = RoundUp(image_info.CreateImageSections(unused_sections), kPageSize);
1411     // There should be no gaps until the next image.
1412     image_offset += image_info.image_size_;
1413   }
1414
1415   // Transform each object's bin slot into an offset which will be used to do the final copy.
1416   heap->VisitObjects(UnbinObjectsIntoOffsetCallback, this);
1417
1418   // DCHECK_EQ(image_end_, GetBinSizeSum(kBinMirrorCount) + image_objects_offset_begin_);
1419
1420   size_t i = 0;
1421   for (ImageInfo& image_info : image_infos_) {
1422     image_info.image_roots_address_ = PointerToLowMemUInt32(GetImageAddress(image_roots[i].Get()));
1423     i++;
1424   }
1425
1426   // Update the native relocations by adding their bin sums.
1427   for (auto& pair : native_object_relocations_) {
1428     NativeObjectRelocation& relocation = pair.second;
1429     Bin bin_type = BinTypeForNativeRelocationType(relocation.type);
1430     ImageInfo& image_info = GetImageInfo(relocation.oat_index);
1431     relocation.offset += image_info.bin_slot_offsets_[bin_type];
1432   }
1433
1434   // Note that image_info.image_end_ is left at end of used mirror object section.
1435 }
1436
1437 size_t ImageWriter::ImageInfo::CreateImageSections(ImageSection* out_sections) const {
1438   DCHECK(out_sections != nullptr);
1439
1440   // Do not round up any sections here that are represented by the bins since it will break
1441   // offsets.
1442
1443   // Objects section
1444   ImageSection* objects_section = &out_sections[ImageHeader::kSectionObjects];
1445   *objects_section = ImageSection(0u, image_end_);
1446
1447   // Add field section.
1448   ImageSection* field_section = &out_sections[ImageHeader::kSectionArtFields];
1449   *field_section = ImageSection(bin_slot_offsets_[kBinArtField], bin_slot_sizes_[kBinArtField]);
1450   CHECK_EQ(bin_slot_offsets_[kBinArtField], field_section->Offset());
1451
1452   // Add method section.
1453   ImageSection* methods_section = &out_sections[ImageHeader::kSectionArtMethods];
1454   *methods_section = ImageSection(
1455       bin_slot_offsets_[kBinArtMethodClean],
1456       bin_slot_sizes_[kBinArtMethodClean] + bin_slot_sizes_[kBinArtMethodDirty]);
1457
1458   // Conflict tables section.
1459   ImageSection* imt_conflict_tables_section = &out_sections[ImageHeader::kSectionIMTConflictTables];
1460   *imt_conflict_tables_section = ImageSection(bin_slot_offsets_[kBinIMTConflictTable],
1461                                               bin_slot_sizes_[kBinIMTConflictTable]);
1462
1463   // Runtime methods section.
1464   ImageSection* runtime_methods_section = &out_sections[ImageHeader::kSectionRuntimeMethods];
1465   *runtime_methods_section = ImageSection(bin_slot_offsets_[kBinRuntimeMethod],
1466                                           bin_slot_sizes_[kBinRuntimeMethod]);
1467
1468   // Add dex cache arrays section.
1469   ImageSection* dex_cache_arrays_section = &out_sections[ImageHeader::kSectionDexCacheArrays];
1470   *dex_cache_arrays_section = ImageSection(bin_slot_offsets_[kBinDexCacheArray],
1471                                            bin_slot_sizes_[kBinDexCacheArray]);
1472
1473   // Round up to the alignment the string table expects. See HashSet::WriteToMemory.
1474   size_t cur_pos = RoundUp(dex_cache_arrays_section->End(), sizeof(uint64_t));
1475   // Calculate the size of the interned strings.
1476   ImageSection* interned_strings_section = &out_sections[ImageHeader::kSectionInternedStrings];
1477   *interned_strings_section = ImageSection(cur_pos, intern_table_bytes_);
1478   cur_pos = interned_strings_section->End();
1479   // Round up to the alignment the class table expects. See HashSet::WriteToMemory.
1480   cur_pos = RoundUp(cur_pos, sizeof(uint64_t));
1481   // Calculate the size of the class table section.
1482   ImageSection* class_table_section = &out_sections[ImageHeader::kSectionClassTable];
1483   *class_table_section = ImageSection(cur_pos, class_table_bytes_);
1484   cur_pos = class_table_section->End();
1485   // Image end goes right before the start of the image bitmap.
1486   return cur_pos;
1487 }
1488
1489 void ImageWriter::CreateHeader(size_t oat_index) {
1490   ImageInfo& image_info = GetImageInfo(oat_index);
1491   const uint8_t* oat_file_begin = image_info.oat_file_begin_;
1492   const uint8_t* oat_file_end = oat_file_begin + image_info.oat_loaded_size_;
1493   const uint8_t* oat_data_end = image_info.oat_data_begin_ + image_info.oat_size_;
1494
1495   // Create the image sections.
1496   ImageSection sections[ImageHeader::kSectionCount];
1497   const size_t image_end = image_info.CreateImageSections(sections);
1498
1499   // Finally bitmap section.
1500   const size_t bitmap_bytes = image_info.image_bitmap_->Size();
1501   auto* bitmap_section = &sections[ImageHeader::kSectionImageBitmap];
1502   *bitmap_section = ImageSection(RoundUp(image_end, kPageSize), RoundUp(bitmap_bytes, kPageSize));
1503   if (VLOG_IS_ON(compiler)) {
1504     LOG(INFO) << "Creating header for " << oat_filenames_[oat_index];
1505     size_t idx = 0;
1506     for (const ImageSection& section : sections) {
1507       LOG(INFO) << static_cast<ImageHeader::ImageSections>(idx) << " " << section;
1508       ++idx;
1509     }
1510     LOG(INFO) << "Methods: clean=" << clean_methods_ << " dirty=" << dirty_methods_;
1511     LOG(INFO) << "Image roots address=" << std::hex << image_info.image_roots_address_ << std::dec;
1512     LOG(INFO) << "Image begin=" << std::hex << reinterpret_cast<uintptr_t>(global_image_begin_)
1513               << " Image offset=" << image_info.image_offset_ << std::dec;
1514     LOG(INFO) << "Oat file begin=" << std::hex << reinterpret_cast<uintptr_t>(oat_file_begin)
1515               << " Oat data begin=" << reinterpret_cast<uintptr_t>(image_info.oat_data_begin_)
1516               << " Oat data end=" << reinterpret_cast<uintptr_t>(oat_data_end)
1517               << " Oat file end=" << reinterpret_cast<uintptr_t>(oat_file_end);
1518   }
1519   // Store boot image info for app image so that we can relocate.
1520   uint32_t boot_image_begin = 0;
1521   uint32_t boot_image_end = 0;
1522   uint32_t boot_oat_begin = 0;
1523   uint32_t boot_oat_end = 0;
1524   gc::Heap* const heap = Runtime::Current()->GetHeap();
1525   heap->GetBootImagesSize(&boot_image_begin, &boot_image_end, &boot_oat_begin, &boot_oat_end);
1526
1527   // Create the header, leave 0 for data size since we will fill this in as we are writing the
1528   // image.
1529   new (image_info.image_->Begin()) ImageHeader(PointerToLowMemUInt32(image_info.image_begin_),
1530                                                image_end,
1531                                                sections,
1532                                                image_info.image_roots_address_,
1533                                                image_info.oat_checksum_,
1534                                                PointerToLowMemUInt32(oat_file_begin),
1535                                                PointerToLowMemUInt32(image_info.oat_data_begin_),
1536                                                PointerToLowMemUInt32(oat_data_end),
1537                                                PointerToLowMemUInt32(oat_file_end),
1538                                                boot_image_begin,
1539                                                boot_image_end - boot_image_begin,
1540                                                boot_oat_begin,
1541                                                boot_oat_end - boot_oat_begin,
1542                                                target_ptr_size_,
1543                                                compile_pic_,
1544                                                /*is_pic*/compile_app_image_,
1545                                                image_storage_mode_,
1546                                                /*data_size*/0u);
1547 }
1548
1549 ArtMethod* ImageWriter::GetImageMethodAddress(ArtMethod* method) {
1550   auto it = native_object_relocations_.find(method);
1551   CHECK(it != native_object_relocations_.end()) << PrettyMethod(method) << " @ " << method;
1552   size_t oat_index = GetOatIndex(method->GetDexCache());
1553   ImageInfo& image_info = GetImageInfo(oat_index);
1554   CHECK_GE(it->second.offset, image_info.image_end_) << "ArtMethods should be after Objects";
1555   return reinterpret_cast<ArtMethod*>(image_info.image_begin_ + it->second.offset);
1556 }
1557
1558 class FixupRootVisitor : public RootVisitor {
1559  public:
1560   explicit FixupRootVisitor(ImageWriter* image_writer) : image_writer_(image_writer) {
1561   }
1562
1563   void VisitRoots(mirror::Object*** roots, size_t count, const RootInfo& info ATTRIBUTE_UNUSED)
1564       OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
1565     for (size_t i = 0; i < count; ++i) {
1566       *roots[i] = image_writer_->GetImageAddress(*roots[i]);
1567     }
1568   }
1569
1570   void VisitRoots(mirror::CompressedReference<mirror::Object>** roots, size_t count,
1571                   const RootInfo& info ATTRIBUTE_UNUSED)
1572       OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
1573     for (size_t i = 0; i < count; ++i) {
1574       roots[i]->Assign(image_writer_->GetImageAddress(roots[i]->AsMirrorPtr()));
1575     }
1576   }
1577
1578  private:
1579   ImageWriter* const image_writer_;
1580 };
1581
1582 void ImageWriter::CopyAndFixupImtConflictTable(ImtConflictTable* orig, ImtConflictTable* copy) {
1583   const size_t count = orig->NumEntries(target_ptr_size_);
1584   for (size_t i = 0; i < count; ++i) {
1585     ArtMethod* interface_method = orig->GetInterfaceMethod(i, target_ptr_size_);
1586     ArtMethod* implementation_method = orig->GetImplementationMethod(i, target_ptr_size_);
1587     copy->SetInterfaceMethod(i, target_ptr_size_, NativeLocationInImage(interface_method));
1588     copy->SetImplementationMethod(i,
1589                                   target_ptr_size_,
1590                                   NativeLocationInImage(implementation_method));
1591   }
1592 }
1593
1594 void ImageWriter::CopyAndFixupNativeData(size_t oat_index) {
1595   const ImageInfo& image_info = GetImageInfo(oat_index);
1596   // Copy ArtFields and methods to their locations and update the array for convenience.
1597   for (auto& pair : native_object_relocations_) {
1598     NativeObjectRelocation& relocation = pair.second;
1599     // Only work with fields and methods that are in the current oat file.
1600     if (relocation.oat_index != oat_index) {
1601       continue;
1602     }
1603     auto* dest = image_info.image_->Begin() + relocation.offset;
1604     DCHECK_GE(dest, image_info.image_->Begin() + image_info.image_end_);
1605     DCHECK(!IsInBootImage(pair.first));
1606     switch (relocation.type) {
1607       case kNativeObjectRelocationTypeArtField: {
1608         memcpy(dest, pair.first, sizeof(ArtField));
1609         reinterpret_cast<ArtField*>(dest)->SetDeclaringClass(
1610             GetImageAddress(reinterpret_cast<ArtField*>(pair.first)->GetDeclaringClass()));
1611         break;
1612       }
1613       case kNativeObjectRelocationTypeRuntimeMethod:
1614       case kNativeObjectRelocationTypeArtMethodClean:
1615       case kNativeObjectRelocationTypeArtMethodDirty: {
1616         CopyAndFixupMethod(reinterpret_cast<ArtMethod*>(pair.first),
1617                            reinterpret_cast<ArtMethod*>(dest),
1618                            image_info);
1619         break;
1620       }
1621       // For arrays, copy just the header since the elements will get copied by their corresponding
1622       // relocations.
1623       case kNativeObjectRelocationTypeArtFieldArray: {
1624         memcpy(dest, pair.first, LengthPrefixedArray<ArtField>::ComputeSize(0));
1625         break;
1626       }
1627       case kNativeObjectRelocationTypeArtMethodArrayClean:
1628       case kNativeObjectRelocationTypeArtMethodArrayDirty: {
1629         size_t size = ArtMethod::Size(target_ptr_size_);
1630         size_t alignment = ArtMethod::Alignment(target_ptr_size_);
1631         memcpy(dest, pair.first, LengthPrefixedArray<ArtMethod>::ComputeSize(0, size, alignment));
1632         // Clear padding to avoid non-deterministic data in the image (and placate valgrind).
1633         reinterpret_cast<LengthPrefixedArray<ArtMethod>*>(dest)->ClearPadding(size, alignment);
1634         break;
1635       }
1636       case kNativeObjectRelocationTypeDexCacheArray:
1637         // Nothing to copy here, everything is done in FixupDexCache().
1638         break;
1639       case kNativeObjectRelocationTypeIMTConflictTable: {
1640         auto* orig_table = reinterpret_cast<ImtConflictTable*>(pair.first);
1641         CopyAndFixupImtConflictTable(
1642             orig_table,
1643             new(dest)ImtConflictTable(orig_table->NumEntries(target_ptr_size_), target_ptr_size_));
1644         break;
1645       }
1646     }
1647   }
1648   // Fixup the image method roots.
1649   auto* image_header = reinterpret_cast<ImageHeader*>(image_info.image_->Begin());
1650   for (size_t i = 0; i < ImageHeader::kImageMethodsCount; ++i) {
1651     ArtMethod* method = image_methods_[i];
1652     CHECK(method != nullptr);
1653     if (!IsInBootImage(method)) {
1654       method = NativeLocationInImage(method);
1655     }
1656     image_header->SetImageMethod(static_cast<ImageHeader::ImageMethod>(i), method);
1657   }
1658   FixupRootVisitor root_visitor(this);
1659
1660   // Write the intern table into the image.
1661   if (image_info.intern_table_bytes_ > 0) {
1662     const ImageSection& intern_table_section = image_header->GetImageSection(
1663         ImageHeader::kSectionInternedStrings);
1664     InternTable* const intern_table = image_info.intern_table_.get();
1665     uint8_t* const intern_table_memory_ptr =
1666         image_info.image_->Begin() + intern_table_section.Offset();
1667     const size_t intern_table_bytes = intern_table->WriteToMemory(intern_table_memory_ptr);
1668     CHECK_EQ(intern_table_bytes, image_info.intern_table_bytes_);
1669     // Fixup the pointers in the newly written intern table to contain image addresses.
1670     InternTable temp_intern_table;
1671     // Note that we require that ReadFromMemory does not make an internal copy of the elements so that
1672     // the VisitRoots() will update the memory directly rather than the copies.
1673     // This also relies on visit roots not doing any verification which could fail after we update
1674     // the roots to be the image addresses.
1675     temp_intern_table.AddTableFromMemory(intern_table_memory_ptr);
1676     CHECK_EQ(temp_intern_table.Size(), intern_table->Size());
1677     temp_intern_table.VisitRoots(&root_visitor, kVisitRootFlagAllRoots);
1678   }
1679   // Write the class table(s) into the image. class_table_bytes_ may be 0 if there are multiple
1680   // class loaders. Writing multiple class tables into the image is currently unsupported.
1681   if (image_info.class_table_bytes_ > 0u) {
1682     const ImageSection& class_table_section = image_header->GetImageSection(
1683         ImageHeader::kSectionClassTable);
1684     uint8_t* const class_table_memory_ptr =
1685         image_info.image_->Begin() + class_table_section.Offset();
1686     ReaderMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
1687
1688     ClassTable* table = image_info.class_table_.get();
1689     CHECK(table != nullptr);
1690     const size_t class_table_bytes = table->WriteToMemory(class_table_memory_ptr);
1691     CHECK_EQ(class_table_bytes, image_info.class_table_bytes_);
1692     // Fixup the pointers in the newly written class table to contain image addresses. See
1693     // above comment for intern tables.
1694     ClassTable temp_class_table;
1695     temp_class_table.ReadFromMemory(class_table_memory_ptr);
1696     CHECK_EQ(temp_class_table.NumZygoteClasses(), table->NumNonZygoteClasses() +
1697              table->NumZygoteClasses());
1698     BufferedRootVisitor<kDefaultBufferedRootCount> buffered_visitor(&root_visitor,
1699                                                                     RootInfo(kRootUnknown));
1700     temp_class_table.VisitRoots(buffered_visitor);
1701   }
1702 }
1703
1704 void ImageWriter::CopyAndFixupObjects() {
1705   gc::Heap* heap = Runtime::Current()->GetHeap();
1706   heap->VisitObjects(CopyAndFixupObjectsCallback, this);
1707   // Fix up the object previously had hash codes.
1708   for (const auto& hash_pair : saved_hashcode_map_) {
1709     Object* obj = hash_pair.first;
1710     DCHECK_EQ(obj->GetLockWord<kVerifyNone>(false).ReadBarrierState(), 0U);
1711     obj->SetLockWord<kVerifyNone>(LockWord::FromHashCode(hash_pair.second, 0U), false);
1712   }
1713   saved_hashcode_map_.clear();
1714 }
1715
1716 void ImageWriter::CopyAndFixupObjectsCallback(Object* obj, void* arg) {
1717   DCHECK(obj != nullptr);
1718   DCHECK(arg != nullptr);
1719   reinterpret_cast<ImageWriter*>(arg)->CopyAndFixupObject(obj);
1720 }
1721
1722 void ImageWriter::FixupPointerArray(mirror::Object* dst, mirror::PointerArray* arr,
1723                                     mirror::Class* klass, Bin array_type) {
1724   CHECK(klass->IsArrayClass());
1725   CHECK(arr->IsIntArray() || arr->IsLongArray()) << PrettyClass(klass) << " " << arr;
1726   // Fixup int and long pointers for the ArtMethod or ArtField arrays.
1727   const size_t num_elements = arr->GetLength();
1728   dst->SetClass(GetImageAddress(arr->GetClass()));
1729   auto* dest_array = down_cast<mirror::PointerArray*>(dst);
1730   for (size_t i = 0, count = num_elements; i < count; ++i) {
1731     void* elem = arr->GetElementPtrSize<void*>(i, target_ptr_size_);
1732     if (elem != nullptr && !IsInBootImage(elem)) {
1733       auto it = native_object_relocations_.find(elem);
1734       if (UNLIKELY(it == native_object_relocations_.end())) {
1735         if (it->second.IsArtMethodRelocation()) {
1736           auto* method = reinterpret_cast<ArtMethod*>(elem);
1737           LOG(FATAL) << "No relocation entry for ArtMethod " << PrettyMethod(method) << " @ "
1738               << method << " idx=" << i << "/" << num_elements << " with declaring class "
1739               << PrettyClass(method->GetDeclaringClass());
1740         } else {
1741           CHECK_EQ(array_type, kBinArtField);
1742           auto* field = reinterpret_cast<ArtField*>(elem);
1743           LOG(FATAL) << "No relocation entry for ArtField " << PrettyField(field) << " @ "
1744               << field << " idx=" << i << "/" << num_elements << " with declaring class "
1745               << PrettyClass(field->GetDeclaringClass());
1746         }
1747         UNREACHABLE();
1748       } else {
1749         ImageInfo& image_info = GetImageInfo(it->second.oat_index);
1750         elem = image_info.image_begin_ + it->second.offset;
1751       }
1752     }
1753     dest_array->SetElementPtrSize<false, true>(i, elem, target_ptr_size_);
1754   }
1755 }
1756
1757 void ImageWriter::CopyAndFixupObject(Object* obj) {
1758   if (IsInBootImage(obj)) {
1759     return;
1760   }
1761   size_t offset = GetImageOffset(obj);
1762   size_t oat_index = GetOatIndex(obj);
1763   ImageInfo& image_info = GetImageInfo(oat_index);
1764   auto* dst = reinterpret_cast<Object*>(image_info.image_->Begin() + offset);
1765   DCHECK_LT(offset, image_info.image_end_);
1766   const auto* src = reinterpret_cast<const uint8_t*>(obj);
1767
1768   image_info.image_bitmap_->Set(dst);  // Mark the obj as live.
1769
1770   const size_t n = obj->SizeOf();
1771   DCHECK_LE(offset + n, image_info.image_->Size());
1772   memcpy(dst, src, n);
1773
1774   // Write in a hash code of objects which have inflated monitors or a hash code in their monitor
1775   // word.
1776   const auto it = saved_hashcode_map_.find(obj);
1777   dst->SetLockWord(it != saved_hashcode_map_.end() ?
1778       LockWord::FromHashCode(it->second, 0u) : LockWord::Default(), false);
1779   FixupObject(obj, dst);
1780 }
1781
1782 // Rewrite all the references in the copied object to point to their image address equivalent
1783 class FixupVisitor {
1784  public:
1785   FixupVisitor(ImageWriter* image_writer, Object* copy) : image_writer_(image_writer), copy_(copy) {
1786   }
1787
1788   // Ignore class roots since we don't have a way to map them to the destination. These are handled
1789   // with other logic.
1790   void VisitRootIfNonNull(mirror::CompressedReference<mirror::Object>* root ATTRIBUTE_UNUSED)
1791       const {}
1792   void VisitRoot(mirror::CompressedReference<mirror::Object>* root ATTRIBUTE_UNUSED) const {}
1793
1794
1795   void operator()(Object* obj, MemberOffset offset, bool is_static ATTRIBUTE_UNUSED) const
1796       REQUIRES(Locks::mutator_lock_, Locks::heap_bitmap_lock_) {
1797     Object* ref = obj->GetFieldObject<Object, kVerifyNone>(offset);
1798     // Use SetFieldObjectWithoutWriteBarrier to avoid card marking since we are writing to the
1799     // image.
1800     copy_->SetFieldObjectWithoutWriteBarrier<false, true, kVerifyNone>(
1801         offset,
1802         image_writer_->GetImageAddress(ref));
1803   }
1804
1805   // java.lang.ref.Reference visitor.
1806   void operator()(mirror::Class* klass ATTRIBUTE_UNUSED, mirror::Reference* ref) const
1807       SHARED_REQUIRES(Locks::mutator_lock_) REQUIRES(Locks::heap_bitmap_lock_) {
1808     copy_->SetFieldObjectWithoutWriteBarrier<false, true, kVerifyNone>(
1809         mirror::Reference::ReferentOffset(),
1810         image_writer_->GetImageAddress(ref->GetReferent()));
1811   }
1812
1813  protected:
1814   ImageWriter* const image_writer_;
1815   mirror::Object* const copy_;
1816 };
1817
1818 class FixupClassVisitor FINAL : public FixupVisitor {
1819  public:
1820   FixupClassVisitor(ImageWriter* image_writer, Object* copy) : FixupVisitor(image_writer, copy) {
1821   }
1822
1823   void operator()(Object* obj, MemberOffset offset, bool is_static ATTRIBUTE_UNUSED) const
1824       REQUIRES(Locks::mutator_lock_, Locks::heap_bitmap_lock_) {
1825     DCHECK(obj->IsClass());
1826     FixupVisitor::operator()(obj, offset, /*is_static*/false);
1827   }
1828
1829   void operator()(mirror::Class* klass ATTRIBUTE_UNUSED,
1830                   mirror::Reference* ref ATTRIBUTE_UNUSED) const
1831       SHARED_REQUIRES(Locks::mutator_lock_) REQUIRES(Locks::heap_bitmap_lock_) {
1832     LOG(FATAL) << "Reference not expected here.";
1833   }
1834 };
1835
1836 uintptr_t ImageWriter::NativeOffsetInImage(void* obj) {
1837   DCHECK(obj != nullptr);
1838   DCHECK(!IsInBootImage(obj));
1839   auto it = native_object_relocations_.find(obj);
1840   CHECK(it != native_object_relocations_.end()) << obj << " spaces "
1841       << Runtime::Current()->GetHeap()->DumpSpaces();
1842   const NativeObjectRelocation& relocation = it->second;
1843   return relocation.offset;
1844 }
1845
1846 template <typename T>
1847 T* ImageWriter::NativeLocationInImage(T* obj) {
1848   if (obj == nullptr || IsInBootImage(obj)) {
1849     return obj;
1850   } else {
1851     auto it = native_object_relocations_.find(obj);
1852     CHECK(it != native_object_relocations_.end()) << obj << " spaces "
1853         << Runtime::Current()->GetHeap()->DumpSpaces();
1854     const NativeObjectRelocation& relocation = it->second;
1855     ImageInfo& image_info = GetImageInfo(relocation.oat_index);
1856     return reinterpret_cast<T*>(image_info.image_begin_ + relocation.offset);
1857   }
1858 }
1859
1860 template <typename T>
1861 T* ImageWriter::NativeCopyLocation(T* obj, mirror::DexCache* dex_cache) {
1862   if (obj == nullptr || IsInBootImage(obj)) {
1863     return obj;
1864   } else {
1865     size_t oat_index = GetOatIndexForDexCache(dex_cache);
1866     ImageInfo& image_info = GetImageInfo(oat_index);
1867     return reinterpret_cast<T*>(image_info.image_->Begin() + NativeOffsetInImage(obj));
1868   }
1869 }
1870
1871 class NativeLocationVisitor {
1872  public:
1873   explicit NativeLocationVisitor(ImageWriter* image_writer) : image_writer_(image_writer) {}
1874
1875   template <typename T>
1876   T* operator()(T* ptr) const SHARED_REQUIRES(Locks::mutator_lock_) {
1877     return image_writer_->NativeLocationInImage(ptr);
1878   }
1879
1880  private:
1881   ImageWriter* const image_writer_;
1882 };
1883
1884 void ImageWriter::FixupClass(mirror::Class* orig, mirror::Class* copy) {
1885   orig->FixupNativePointers(copy, target_ptr_size_, NativeLocationVisitor(this));
1886   FixupClassVisitor visitor(this, copy);
1887   static_cast<mirror::Object*>(orig)->VisitReferences(visitor, visitor);
1888
1889   // Remove the clinitThreadId. This is required for image determinism.
1890   copy->SetClinitThreadId(static_cast<pid_t>(0));
1891 }
1892
1893 void ImageWriter::FixupObject(Object* orig, Object* copy) {
1894   DCHECK(orig != nullptr);
1895   DCHECK(copy != nullptr);
1896   if (kUseBakerOrBrooksReadBarrier) {
1897     orig->AssertReadBarrierPointer();
1898     if (kUseBrooksReadBarrier) {
1899       // Note the address 'copy' isn't the same as the image address of 'orig'.
1900       copy->SetReadBarrierPointer(GetImageAddress(orig));
1901       DCHECK_EQ(copy->GetReadBarrierPointer(), GetImageAddress(orig));
1902     }
1903   }
1904   auto* klass = orig->GetClass();
1905   if (klass->IsIntArrayClass() || klass->IsLongArrayClass()) {
1906     // Is this a native pointer array?
1907     auto it = pointer_arrays_.find(down_cast<mirror::PointerArray*>(orig));
1908     if (it != pointer_arrays_.end()) {
1909       // Should only need to fixup every pointer array exactly once.
1910       FixupPointerArray(copy, down_cast<mirror::PointerArray*>(orig), klass, it->second);
1911       pointer_arrays_.erase(it);
1912       return;
1913     }
1914   }
1915   if (orig->IsClass()) {
1916     FixupClass(orig->AsClass<kVerifyNone>(), down_cast<mirror::Class*>(copy));
1917   } else {
1918     if (klass == mirror::Method::StaticClass() || klass == mirror::Constructor::StaticClass()) {
1919       // Need to go update the ArtMethod.
1920       auto* dest = down_cast<mirror::AbstractMethod*>(copy);
1921       auto* src = down_cast<mirror::AbstractMethod*>(orig);
1922       ArtMethod* src_method = src->GetArtMethod();
1923       auto it = native_object_relocations_.find(src_method);
1924       CHECK(it != native_object_relocations_.end())
1925           << "Missing relocation for AbstractMethod.artMethod " << PrettyMethod(src_method);
1926       dest->SetArtMethod(
1927           reinterpret_cast<ArtMethod*>(global_image_begin_ + it->second.offset));
1928     } else if (!klass->IsArrayClass()) {
1929       ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
1930       if (klass == class_linker->GetClassRoot(ClassLinker::kJavaLangDexCache)) {
1931         FixupDexCache(down_cast<mirror::DexCache*>(orig), down_cast<mirror::DexCache*>(copy));
1932       } else if (klass->IsClassLoaderClass()) {
1933         mirror::ClassLoader* copy_loader = down_cast<mirror::ClassLoader*>(copy);
1934         // If src is a ClassLoader, set the class table to null so that it gets recreated by the
1935         // ClassLoader.
1936         copy_loader->SetClassTable(nullptr);
1937         // Also set allocator to null to be safe. The allocator is created when we create the class
1938         // table. We also never expect to unload things in the image since they are held live as
1939         // roots.
1940         copy_loader->SetAllocator(nullptr);
1941       }
1942     }
1943     FixupVisitor visitor(this, copy);
1944     orig->VisitReferences(visitor, visitor);
1945   }
1946 }
1947
1948
1949 class ImageAddressVisitor {
1950  public:
1951   explicit ImageAddressVisitor(ImageWriter* image_writer) : image_writer_(image_writer) {}
1952
1953   template <typename T>
1954   T* operator()(T* ptr) const SHARED_REQUIRES(Locks::mutator_lock_) {
1955     return image_writer_->GetImageAddress(ptr);
1956   }
1957
1958  private:
1959   ImageWriter* const image_writer_;
1960 };
1961
1962
1963 void ImageWriter::FixupDexCache(mirror::DexCache* orig_dex_cache,
1964                                 mirror::DexCache* copy_dex_cache) {
1965   // Though the DexCache array fields are usually treated as native pointers, we set the full
1966   // 64-bit values here, clearing the top 32 bits for 32-bit targets. The zero-extension is
1967   // done by casting to the unsigned type uintptr_t before casting to int64_t, i.e.
1968   //     static_cast<int64_t>(reinterpret_cast<uintptr_t>(image_begin_ + offset))).
1969   GcRoot<mirror::String>* orig_strings = orig_dex_cache->GetStrings();
1970   if (orig_strings != nullptr) {
1971     copy_dex_cache->SetFieldPtrWithSize<false>(mirror::DexCache::StringsOffset(),
1972                                                NativeLocationInImage(orig_strings),
1973                                                /*pointer size*/8u);
1974     orig_dex_cache->FixupStrings(NativeCopyLocation(orig_strings, orig_dex_cache),
1975                                  ImageAddressVisitor(this));
1976   }
1977   GcRoot<mirror::Class>* orig_types = orig_dex_cache->GetResolvedTypes();
1978   if (orig_types != nullptr) {
1979     copy_dex_cache->SetFieldPtrWithSize<false>(mirror::DexCache::ResolvedTypesOffset(),
1980                                                NativeLocationInImage(orig_types),
1981                                                /*pointer size*/8u);
1982     orig_dex_cache->FixupResolvedTypes(NativeCopyLocation(orig_types, orig_dex_cache),
1983                                        ImageAddressVisitor(this));
1984   }
1985   ArtMethod** orig_methods = orig_dex_cache->GetResolvedMethods();
1986   if (orig_methods != nullptr) {
1987     copy_dex_cache->SetFieldPtrWithSize<false>(mirror::DexCache::ResolvedMethodsOffset(),
1988                                                NativeLocationInImage(orig_methods),
1989                                                /*pointer size*/8u);
1990     ArtMethod** copy_methods = NativeCopyLocation(orig_methods, orig_dex_cache);
1991     for (size_t i = 0, num = orig_dex_cache->NumResolvedMethods(); i != num; ++i) {
1992       ArtMethod* orig = mirror::DexCache::GetElementPtrSize(orig_methods, i, target_ptr_size_);
1993       // NativeLocationInImage also handles runtime methods since these have relocation info.
1994       ArtMethod* copy = NativeLocationInImage(orig);
1995       mirror::DexCache::SetElementPtrSize(copy_methods, i, copy, target_ptr_size_);
1996     }
1997   }
1998   ArtField** orig_fields = orig_dex_cache->GetResolvedFields();
1999   if (orig_fields != nullptr) {
2000     copy_dex_cache->SetFieldPtrWithSize<false>(mirror::DexCache::ResolvedFieldsOffset(),
2001                                                NativeLocationInImage(orig_fields),
2002                                                /*pointer size*/8u);
2003     ArtField** copy_fields = NativeCopyLocation(orig_fields, orig_dex_cache);
2004     for (size_t i = 0, num = orig_dex_cache->NumResolvedFields(); i != num; ++i) {
2005       ArtField* orig = mirror::DexCache::GetElementPtrSize(orig_fields, i, target_ptr_size_);
2006       ArtField* copy = NativeLocationInImage(orig);
2007       mirror::DexCache::SetElementPtrSize(copy_fields, i, copy, target_ptr_size_);
2008     }
2009   }
2010
2011   // Remove the DexFile pointers. They will be fixed up when the runtime loads the oat file. Leaving
2012   // compiler pointers in here will make the output non-deterministic.
2013   copy_dex_cache->SetDexFile(nullptr);
2014 }
2015
2016 const uint8_t* ImageWriter::GetOatAddress(OatAddress type) const {
2017   DCHECK_LT(type, kOatAddressCount);
2018   // If we are compiling an app image, we need to use the stubs of the boot image.
2019   if (compile_app_image_) {
2020     // Use the current image pointers.
2021     const std::vector<gc::space::ImageSpace*>& image_spaces =
2022         Runtime::Current()->GetHeap()->GetBootImageSpaces();
2023     DCHECK(!image_spaces.empty());
2024     const OatFile* oat_file = image_spaces[0]->GetOatFile();
2025     CHECK(oat_file != nullptr);
2026     const OatHeader& header = oat_file->GetOatHeader();
2027     switch (type) {
2028       // TODO: We could maybe clean this up if we stored them in an array in the oat header.
2029       case kOatAddressQuickGenericJNITrampoline:
2030         return static_cast<const uint8_t*>(header.GetQuickGenericJniTrampoline());
2031       case kOatAddressInterpreterToInterpreterBridge:
2032         return static_cast<const uint8_t*>(header.GetInterpreterToInterpreterBridge());
2033       case kOatAddressInterpreterToCompiledCodeBridge:
2034         return static_cast<const uint8_t*>(header.GetInterpreterToCompiledCodeBridge());
2035       case kOatAddressJNIDlsymLookup:
2036         return static_cast<const uint8_t*>(header.GetJniDlsymLookup());
2037       case kOatAddressQuickIMTConflictTrampoline:
2038         return static_cast<const uint8_t*>(header.GetQuickImtConflictTrampoline());
2039       case kOatAddressQuickResolutionTrampoline:
2040         return static_cast<const uint8_t*>(header.GetQuickResolutionTrampoline());
2041       case kOatAddressQuickToInterpreterBridge:
2042         return static_cast<const uint8_t*>(header.GetQuickToInterpreterBridge());
2043       default:
2044         UNREACHABLE();
2045     }
2046   }
2047   const ImageInfo& primary_image_info = GetImageInfo(0);
2048   return GetOatAddressForOffset(primary_image_info.oat_address_offsets_[type], primary_image_info);
2049 }
2050
2051 const uint8_t* ImageWriter::GetQuickCode(ArtMethod* method,
2052                                          const ImageInfo& image_info,
2053                                          bool* quick_is_interpreted) {
2054   DCHECK(!method->IsResolutionMethod()) << PrettyMethod(method);
2055   DCHECK_NE(method, Runtime::Current()->GetImtConflictMethod()) << PrettyMethod(method);
2056   DCHECK(!method->IsImtUnimplementedMethod()) << PrettyMethod(method);
2057   DCHECK(method->IsInvokable()) << PrettyMethod(method);
2058   DCHECK(!IsInBootImage(method)) << PrettyMethod(method);
2059
2060   // Use original code if it exists. Otherwise, set the code pointer to the resolution
2061   // trampoline.
2062
2063   // Quick entrypoint:
2064   const void* quick_oat_entry_point =
2065       method->GetEntryPointFromQuickCompiledCodePtrSize(target_ptr_size_);
2066   const uint8_t* quick_code;
2067
2068   if (UNLIKELY(IsInBootImage(method->GetDeclaringClass()))) {
2069     DCHECK(method->IsCopied());
2070     // If the code is not in the oat file corresponding to this image (e.g. default methods)
2071     quick_code = reinterpret_cast<const uint8_t*>(quick_oat_entry_point);
2072   } else {
2073     uint32_t quick_oat_code_offset = PointerToLowMemUInt32(quick_oat_entry_point);
2074     quick_code = GetOatAddressForOffset(quick_oat_code_offset, image_info);
2075   }
2076
2077   *quick_is_interpreted = false;
2078   if (quick_code != nullptr && (!method->IsStatic() || method->IsConstructor() ||
2079       method->GetDeclaringClass()->IsInitialized())) {
2080     // We have code for a non-static or initialized method, just use the code.
2081   } else if (quick_code == nullptr && method->IsNative() &&
2082       (!method->IsStatic() || method->GetDeclaringClass()->IsInitialized())) {
2083     // Non-static or initialized native method missing compiled code, use generic JNI version.
2084     quick_code = GetOatAddress(kOatAddressQuickGenericJNITrampoline);
2085   } else if (quick_code == nullptr && !method->IsNative()) {
2086     // We don't have code at all for a non-native method, use the interpreter.
2087     quick_code = GetOatAddress(kOatAddressQuickToInterpreterBridge);
2088     *quick_is_interpreted = true;
2089   } else {
2090     CHECK(!method->GetDeclaringClass()->IsInitialized());
2091     // We have code for a static method, but need to go through the resolution stub for class
2092     // initialization.
2093     quick_code = GetOatAddress(kOatAddressQuickResolutionTrampoline);
2094   }
2095   if (!IsInBootOatFile(quick_code)) {
2096     // DCHECK_GE(quick_code, oat_data_begin_);
2097   }
2098   return quick_code;
2099 }
2100
2101 void ImageWriter::CopyAndFixupMethod(ArtMethod* orig,
2102                                      ArtMethod* copy,
2103                                      const ImageInfo& image_info) {
2104   memcpy(copy, orig, ArtMethod::Size(target_ptr_size_));
2105
2106   copy->SetDeclaringClass(GetImageAddress(orig->GetDeclaringClassUnchecked()));
2107   ArtMethod** orig_resolved_methods = orig->GetDexCacheResolvedMethods(target_ptr_size_);
2108   copy->SetDexCacheResolvedMethods(NativeLocationInImage(orig_resolved_methods), target_ptr_size_);
2109   GcRoot<mirror::Class>* orig_resolved_types = orig->GetDexCacheResolvedTypes(target_ptr_size_);
2110   copy->SetDexCacheResolvedTypes(NativeLocationInImage(orig_resolved_types), target_ptr_size_);
2111
2112   // OatWriter replaces the code_ with an offset value. Here we re-adjust to a pointer relative to
2113   // oat_begin_
2114
2115   // The resolution method has a special trampoline to call.
2116   Runtime* runtime = Runtime::Current();
2117   if (orig->IsRuntimeMethod()) {
2118     ImtConflictTable* orig_table = orig->GetImtConflictTable(target_ptr_size_);
2119     if (orig_table != nullptr) {
2120       // Special IMT conflict method, normal IMT conflict method or unimplemented IMT method.
2121       copy->SetEntryPointFromQuickCompiledCodePtrSize(
2122           GetOatAddress(kOatAddressQuickIMTConflictTrampoline), target_ptr_size_);
2123       copy->SetImtConflictTable(NativeLocationInImage(orig_table), target_ptr_size_);
2124     } else if (UNLIKELY(orig == runtime->GetResolutionMethod())) {
2125       copy->SetEntryPointFromQuickCompiledCodePtrSize(
2126           GetOatAddress(kOatAddressQuickResolutionTrampoline), target_ptr_size_);
2127     } else {
2128       bool found_one = false;
2129       for (size_t i = 0; i < static_cast<size_t>(Runtime::kLastCalleeSaveType); ++i) {
2130         auto idx = static_cast<Runtime::CalleeSaveType>(i);
2131         if (runtime->HasCalleeSaveMethod(idx) && runtime->GetCalleeSaveMethod(idx) == orig) {
2132           found_one = true;
2133           break;
2134         }
2135       }
2136       CHECK(found_one) << "Expected to find callee save method but got " << PrettyMethod(orig);
2137       CHECK(copy->IsRuntimeMethod());
2138     }
2139   } else {
2140     // We assume all methods have code. If they don't currently then we set them to the use the
2141     // resolution trampoline. Abstract methods never have code and so we need to make sure their
2142     // use results in an AbstractMethodError. We use the interpreter to achieve this.
2143     if (UNLIKELY(!orig->IsInvokable())) {
2144       copy->SetEntryPointFromQuickCompiledCodePtrSize(
2145           GetOatAddress(kOatAddressQuickToInterpreterBridge), target_ptr_size_);
2146     } else {
2147       bool quick_is_interpreted;
2148       const uint8_t* quick_code = GetQuickCode(orig, image_info, &quick_is_interpreted);
2149       copy->SetEntryPointFromQuickCompiledCodePtrSize(quick_code, target_ptr_size_);
2150
2151       // JNI entrypoint:
2152       if (orig->IsNative()) {
2153         // The native method's pointer is set to a stub to lookup via dlsym.
2154         // Note this is not the code_ pointer, that is handled above.
2155         copy->SetEntryPointFromJniPtrSize(
2156             GetOatAddress(kOatAddressJNIDlsymLookup), target_ptr_size_);
2157       }
2158     }
2159   }
2160 }
2161
2162 size_t ImageWriter::GetBinSizeSum(ImageWriter::ImageInfo& image_info, ImageWriter::Bin up_to) const {
2163   DCHECK_LE(up_to, kBinSize);
2164   return std::accumulate(&image_info.bin_slot_sizes_[0],
2165                          &image_info.bin_slot_sizes_[up_to],
2166                          /*init*/0);
2167 }
2168
2169 ImageWriter::BinSlot::BinSlot(uint32_t lockword) : lockword_(lockword) {
2170   // These values may need to get updated if more bins are added to the enum Bin
2171   static_assert(kBinBits == 3, "wrong number of bin bits");
2172   static_assert(kBinShift == 27, "wrong number of shift");
2173   static_assert(sizeof(BinSlot) == sizeof(LockWord), "BinSlot/LockWord must have equal sizes");
2174
2175   DCHECK_LT(GetBin(), kBinSize);
2176   DCHECK_ALIGNED(GetIndex(), kObjectAlignment);
2177 }
2178
2179 ImageWriter::BinSlot::BinSlot(Bin bin, uint32_t index)
2180     : BinSlot(index | (static_cast<uint32_t>(bin) << kBinShift)) {
2181   DCHECK_EQ(index, GetIndex());
2182 }
2183
2184 ImageWriter::Bin ImageWriter::BinSlot::GetBin() const {
2185   return static_cast<Bin>((lockword_ & kBinMask) >> kBinShift);
2186 }
2187
2188 uint32_t ImageWriter::BinSlot::GetIndex() const {
2189   return lockword_ & ~kBinMask;
2190 }
2191
2192 ImageWriter::Bin ImageWriter::BinTypeForNativeRelocationType(NativeObjectRelocationType type) {
2193   switch (type) {
2194     case kNativeObjectRelocationTypeArtField:
2195     case kNativeObjectRelocationTypeArtFieldArray:
2196       return kBinArtField;
2197     case kNativeObjectRelocationTypeArtMethodClean:
2198     case kNativeObjectRelocationTypeArtMethodArrayClean:
2199       return kBinArtMethodClean;
2200     case kNativeObjectRelocationTypeArtMethodDirty:
2201     case kNativeObjectRelocationTypeArtMethodArrayDirty:
2202       return kBinArtMethodDirty;
2203     case kNativeObjectRelocationTypeDexCacheArray:
2204       return kBinDexCacheArray;
2205     case kNativeObjectRelocationTypeRuntimeMethod:
2206       return kBinRuntimeMethod;
2207     case kNativeObjectRelocationTypeIMTConflictTable:
2208       return kBinIMTConflictTable;
2209   }
2210   UNREACHABLE();
2211 }
2212
2213 size_t ImageWriter::GetOatIndex(mirror::Object* obj) const {
2214   if (compile_app_image_) {
2215     return GetDefaultOatIndex();
2216   } else {
2217     mirror::DexCache* dex_cache =
2218         obj->IsDexCache() ? obj->AsDexCache()
2219                           : obj->IsClass() ? obj->AsClass()->GetDexCache()
2220                                            : obj->GetClass()->GetDexCache();
2221     return GetOatIndexForDexCache(dex_cache);
2222   }
2223 }
2224
2225 size_t ImageWriter::GetOatIndexForDexFile(const DexFile* dex_file) const {
2226   if (compile_app_image_) {
2227     return GetDefaultOatIndex();
2228   } else {
2229     auto it = dex_file_oat_index_map_.find(dex_file);
2230     DCHECK(it != dex_file_oat_index_map_.end()) << dex_file->GetLocation();
2231     return it->second;
2232   }
2233 }
2234
2235 size_t ImageWriter::GetOatIndexForDexCache(mirror::DexCache* dex_cache) const {
2236   if (dex_cache == nullptr) {
2237     return GetDefaultOatIndex();
2238   } else {
2239     return GetOatIndexForDexFile(dex_cache->GetDexFile());
2240   }
2241 }
2242
2243 void ImageWriter::UpdateOatFileLayout(size_t oat_index,
2244                                       size_t oat_loaded_size,
2245                                       size_t oat_data_offset,
2246                                       size_t oat_data_size) {
2247   const uint8_t* images_end = image_infos_.back().image_begin_ + image_infos_.back().image_size_;
2248   for (const ImageInfo& info : image_infos_) {
2249     DCHECK_LE(info.image_begin_ + info.image_size_, images_end);
2250   }
2251   DCHECK(images_end != nullptr);  // Image space must be ready.
2252
2253   ImageInfo& cur_image_info = GetImageInfo(oat_index);
2254   cur_image_info.oat_file_begin_ = images_end + cur_image_info.oat_offset_;
2255   cur_image_info.oat_loaded_size_ = oat_loaded_size;
2256   cur_image_info.oat_data_begin_ = cur_image_info.oat_file_begin_ + oat_data_offset;
2257   cur_image_info.oat_size_ = oat_data_size;
2258
2259   if (compile_app_image_) {
2260     CHECK_EQ(oat_filenames_.size(), 1u) << "App image should have no next image.";
2261     return;
2262   }
2263
2264   // Update the oat_offset of the next image info.
2265   if (oat_index + 1u != oat_filenames_.size()) {
2266     // There is a following one.
2267     ImageInfo& next_image_info = GetImageInfo(oat_index + 1u);
2268     next_image_info.oat_offset_ = cur_image_info.oat_offset_ + oat_loaded_size;
2269   }
2270 }
2271
2272 void ImageWriter::UpdateOatFileHeader(size_t oat_index, const OatHeader& oat_header) {
2273   ImageInfo& cur_image_info = GetImageInfo(oat_index);
2274   cur_image_info.oat_checksum_ = oat_header.GetChecksum();
2275
2276   if (oat_index == GetDefaultOatIndex()) {
2277     // Primary oat file, read the trampolines.
2278     cur_image_info.oat_address_offsets_[kOatAddressInterpreterToInterpreterBridge] =
2279         oat_header.GetInterpreterToInterpreterBridgeOffset();
2280     cur_image_info.oat_address_offsets_[kOatAddressInterpreterToCompiledCodeBridge] =
2281         oat_header.GetInterpreterToCompiledCodeBridgeOffset();
2282     cur_image_info.oat_address_offsets_[kOatAddressJNIDlsymLookup] =
2283         oat_header.GetJniDlsymLookupOffset();
2284     cur_image_info.oat_address_offsets_[kOatAddressQuickGenericJNITrampoline] =
2285         oat_header.GetQuickGenericJniTrampolineOffset();
2286     cur_image_info.oat_address_offsets_[kOatAddressQuickIMTConflictTrampoline] =
2287         oat_header.GetQuickImtConflictTrampolineOffset();
2288     cur_image_info.oat_address_offsets_[kOatAddressQuickResolutionTrampoline] =
2289         oat_header.GetQuickResolutionTrampolineOffset();
2290     cur_image_info.oat_address_offsets_[kOatAddressQuickToInterpreterBridge] =
2291         oat_header.GetQuickToInterpreterBridgeOffset();
2292   }
2293 }
2294
2295 ImageWriter::ImageWriter(
2296     const CompilerDriver& compiler_driver,
2297     uintptr_t image_begin,
2298     bool compile_pic,
2299     bool compile_app_image,
2300     ImageHeader::StorageMode image_storage_mode,
2301     const std::vector<const char*>& oat_filenames,
2302     const std::unordered_map<const DexFile*, size_t>& dex_file_oat_index_map)
2303     : compiler_driver_(compiler_driver),
2304       global_image_begin_(reinterpret_cast<uint8_t*>(image_begin)),
2305       image_objects_offset_begin_(0),
2306       compile_pic_(compile_pic),
2307       compile_app_image_(compile_app_image),
2308       target_ptr_size_(InstructionSetPointerSize(compiler_driver_.GetInstructionSet())),
2309       image_infos_(oat_filenames.size()),
2310       dirty_methods_(0u),
2311       clean_methods_(0u),
2312       image_storage_mode_(image_storage_mode),
2313       oat_filenames_(oat_filenames),
2314       dex_file_oat_index_map_(dex_file_oat_index_map) {
2315   CHECK_NE(image_begin, 0U);
2316   std::fill_n(image_methods_, arraysize(image_methods_), nullptr);
2317   CHECK_EQ(compile_app_image, !Runtime::Current()->GetHeap()->GetBootImageSpaces().empty())
2318       << "Compiling a boot image should occur iff there are no boot image spaces loaded";
2319 }
2320
2321 ImageWriter::ImageInfo::ImageInfo()
2322     : intern_table_(new InternTable),
2323       class_table_(new ClassTable) {}
2324
2325 }  // namespace art