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     CHECK(dex_file_oat_index_map_.find(dex_file) != dex_file_oat_index_map_.end())
 441         << "Dex cache should have been pruned " << dex_file->GetLocation()
 442         << "; possibly in class path";
 443     DexCacheArraysLayout layout(target_ptr_size_, dex_file);
 444     DCHECK(layout.Valid());
 445     size_t oat_index = GetOatIndexForDexCache(dex_cache);
 446     ImageInfo& image_info = GetImageInfo(oat_index);
 447     uint32_t start = image_info.dex_cache_array_starts_.Get(dex_file);
 448     DCHECK_EQ(dex_file->NumTypeIds() != 0u, dex_cache->GetResolvedTypes() != nullptr);
 449     AddDexCacheArrayRelocation(dex_cache->GetResolvedTypes(),
 450                                start + layout.TypesOffset(),
 451                                dex_cache);
 452     DCHECK_EQ(dex_file->NumMethodIds() != 0u, dex_cache->GetResolvedMethods() != nullptr);
 453     AddDexCacheArrayRelocation(dex_cache->GetResolvedMethods(),
 454                                start + layout.MethodsOffset(),
 455                                dex_cache);
 456     DCHECK_EQ(dex_file->NumFieldIds() != 0u, dex_cache->GetResolvedFields() != nullptr);
 457     AddDexCacheArrayRelocation(dex_cache->GetResolvedFields(),
 458                                start + layout.FieldsOffset(),
 459                                dex_cache);
 460     DCHECK_EQ(dex_file->NumStringIds() != 0u, dex_cache->GetStrings() != nullptr);
 461     AddDexCacheArrayRelocation(dex_cache->GetStrings(), start + layout.StringsOffset(), dex_cache);
 462   }
 463 }
 464
 465 void ImageWriter::AddDexCacheArrayRelocation(void* array, size_t offset, DexCache* dex_cache) {
 466   if (array != nullptr) {
 467     DCHECK(!IsInBootImage(array));
 468     size_t oat_index = GetOatIndexForDexCache(dex_cache);
 469     native_object_relocations_.emplace(array,
 470         NativeObjectRelocation { oat_index, offset, kNativeObjectRelocationTypeDexCacheArray });
 471   }
 472 }
 473
 474 void ImageWriter::AddMethodPointerArray(mirror::PointerArray* arr) {
 475   DCHECK(arr != nullptr);
 476   if (kIsDebugBuild) {
 477     for (size_t i = 0, len = arr->GetLength(); i < len; i++) {
 478       ArtMethod* method = arr->GetElementPtrSize<ArtMethod*>(i, target_ptr_size_);
 479       if (method != nullptr && !method->IsRuntimeMethod()) {
 480         mirror::Class* klass = method->GetDeclaringClass();
 481         CHECK(klass == nullptr || KeepClass(klass))
 482             << PrettyClass(klass) << " should be a kept class";
 483       }
 484     }
 485   }
 486   // kBinArtMethodClean picked arbitrarily, just required to differentiate between ArtFields and
 487   // ArtMethods.
 488   pointer_arrays_.emplace(arr, kBinArtMethodClean);
 489 }
 490
 491 void ImageWriter::AssignImageBinSlot(mirror::Object* object) {
 492   DCHECK(object != nullptr);
 493   size_t object_size = object->SizeOf();
 494
 495   // The magic happens here. We segregate objects into different bins based
 496   // on how likely they are to get dirty at runtime.
 497   //
 498   // Likely-to-dirty objects get packed together into the same bin so that
 499   // at runtime their page dirtiness ratio (how many dirty objects a page has) is
 500   // maximized.
 501   //
 502   // This means more pages will stay either clean or shared dirty (with zygote) and
 503   // the app will use less of its own (private) memory.
 504   Bin bin = kBinRegular;
 505   size_t current_offset = 0u;
 506
 507   if (kBinObjects) {
 508     //
 509     // Changing the bin of an object is purely a memory-use tuning.
 510     // It has no change on runtime correctness.
 511     //
 512     // Memory analysis has determined that the following types of objects get dirtied
 513     // the most:
 514     //
 515     // * Dex cache arrays are stored in a special bin. The arrays for each dex cache have
 516     //   a fixed layout which helps improve generated code (using PC-relative addressing),
 517     //   so we pre-calculate their offsets separately in PrepareDexCacheArraySlots().
 518     //   Since these arrays are huge, most pages do not overlap other objects and it's not
 519     //   really important where they are for the clean/dirty separation. Due to their
 520     //   special PC-relative addressing, we arbitrarily keep them at the end.
 521     // * Class'es which are verified [their clinit runs only at runtime]
 522     //   - classes in general [because their static fields get overwritten]
 523     //   - initialized classes with all-final statics are unlikely to be ever dirty,
 524     //     so bin them separately
 525     // * Art Methods that are:
 526     //   - native [their native entry point is not looked up until runtime]
 527     //   - have declaring classes that aren't initialized
 528     //            [their interpreter/quick entry points are trampolines until the class
 529     //             becomes initialized]
 530     //
 531     // We also assume the following objects get dirtied either never or extremely rarely:
 532     //  * Strings (they are immutable)
 533     //  * Art methods that aren't native and have initialized declared classes
 534     //
 535     // We assume that "regular" bin objects are highly unlikely to become dirtied,
 536     // so packing them together will not result in a noticeably tighter dirty-to-clean ratio.
 537     //
 538     if (object->IsClass()) {
 539       bin = kBinClassVerified;
 540       mirror::Class* klass = object->AsClass();
 541
 542       // Add non-embedded vtable to the pointer array table if there is one.
 543       auto* vtable = klass->GetVTable();
 544       if (vtable != nullptr) {
 545         AddMethodPointerArray(vtable);
 546       }
 547       auto* iftable = klass->GetIfTable();
 548       if (iftable != nullptr) {
 549         for (int32_t i = 0; i < klass->GetIfTableCount(); ++i) {
 550           if (iftable->GetMethodArrayCount(i) > 0) {
 551             AddMethodPointerArray(iftable->GetMethodArray(i));
 552           }
 553         }
 554       }
 555
 556       if (klass->GetStatus() == Class::kStatusInitialized) {
 557         bin = kBinClassInitialized;
 558
 559         // If the class's static fields are all final, put it into a separate bin
 560         // since it's very likely it will stay clean.
 561         uint32_t num_static_fields = klass->NumStaticFields();
 562         if (num_static_fields == 0) {
 563           bin = kBinClassInitializedFinalStatics;
 564         } else {
 565           // Maybe all the statics are final?
 566           bool all_final = true;
 567           for (uint32_t i = 0; i < num_static_fields; ++i) {
 568             ArtField* field = klass->GetStaticField(i);
 569             if (!field->IsFinal()) {
 570               all_final = false;
 571               break;
 572             }
 573           }
 574
 575           if (all_final) {
 576             bin = kBinClassInitializedFinalStatics;
 577           }
 578         }
 579       }
 580     } else if (object->GetClass<kVerifyNone>()->IsStringClass()) {
 581       bin = kBinString;  // Strings are almost always immutable (except for object header).
 582     } else if (object->GetClass<kVerifyNone>() ==
 583         Runtime::Current()->GetClassLinker()->GetClassRoot(ClassLinker::kJavaLangObject)) {
 584       // Instance of java lang object, probably a lock object. This means it will be dirty when we
 585       // synchronize on it.
 586       bin = kBinMiscDirty;
 587     } else if (object->IsDexCache()) {
 588       // Dex file field becomes dirty when the image is loaded.
 589       bin = kBinMiscDirty;
 590     }
 591     // else bin = kBinRegular
 592   }
 593
 594   size_t oat_index = GetOatIndex(object);
 595   ImageInfo& image_info = GetImageInfo(oat_index);
 596
 597   size_t offset_delta = RoundUp(object_size, kObjectAlignment);  // 64-bit alignment
 598   current_offset = image_info.bin_slot_sizes_[bin];  // How many bytes the current bin is at (aligned).
 599   // Move the current bin size up to accommodate the object we just assigned a bin slot.
 600   image_info.bin_slot_sizes_[bin] += offset_delta;
 601
 602   BinSlot new_bin_slot(bin, current_offset);
 603   SetImageBinSlot(object, new_bin_slot);
 604
 605   ++image_info.bin_slot_count_[bin];
 606
 607   // Grow the image closer to the end by the object we just assigned.
 608   image_info.image_end_ += offset_delta;
 609 }
 610
 611 bool ImageWriter::WillMethodBeDirty(ArtMethod* m) const {
 612   if (m->IsNative()) {
 613     return true;
 614   }
 615   mirror::Class* declaring_class = m->GetDeclaringClass();
 616   // Initialized is highly unlikely to dirty since there's no entry points to mutate.
 617   return declaring_class == nullptr || declaring_class->GetStatus() != Class::kStatusInitialized;
 618 }
 619
 620 bool ImageWriter::IsImageBinSlotAssigned(mirror::Object* object) const {
 621   DCHECK(object != nullptr);
 622
 623   // We always stash the bin slot into a lockword, in the 'forwarding address' state.
 624   // If it's in some other state, then we haven't yet assigned an image bin slot.
 625   if (object->GetLockWord(false).GetState() != LockWord::kForwardingAddress) {
 626     return false;
 627   } else if (kIsDebugBuild) {
 628     LockWord lock_word = object->GetLockWord(false);
 629     size_t offset = lock_word.ForwardingAddress();
 630     BinSlot bin_slot(offset);
 631     size_t oat_index = GetOatIndex(object);
 632     const ImageInfo& image_info = GetImageInfo(oat_index);
 633     DCHECK_LT(bin_slot.GetIndex(), image_info.bin_slot_sizes_[bin_slot.GetBin()])
 634         << "bin slot offset should not exceed the size of that bin";
 635   }
 636   return true;
 637 }
 638
 639 ImageWriter::BinSlot ImageWriter::GetImageBinSlot(mirror::Object* object) const {
 640   DCHECK(object != nullptr);
 641   DCHECK(IsImageBinSlotAssigned(object));
 642
 643   LockWord lock_word = object->GetLockWord(false);
 644   size_t offset = lock_word.ForwardingAddress();  // TODO: ForwardingAddress should be uint32_t
 645   DCHECK_LE(offset, std::numeric_limits<uint32_t>::max());
 646
 647   BinSlot bin_slot(static_cast<uint32_t>(offset));
 648   size_t oat_index = GetOatIndex(object);
 649   const ImageInfo& image_info = GetImageInfo(oat_index);
 650   DCHECK_LT(bin_slot.GetIndex(), image_info.bin_slot_sizes_[bin_slot.GetBin()]);
 651
 652   return bin_slot;
 653 }
 654
 655 bool ImageWriter::AllocMemory() {
 656   for (ImageInfo& image_info : image_infos_) {
 657     ImageSection unused_sections[ImageHeader::kSectionCount];
 658     const size_t length = RoundUp(
 659         image_info.CreateImageSections(unused_sections), kPageSize);
 660
 661     std::string error_msg;
 662     image_info.image_.reset(MemMap::MapAnonymous("image writer image",
 663                                                  nullptr,
 664                                                  length,
 665                                                  PROT_READ | PROT_WRITE,
 666                                                  false,
 667                                                  false,
 668                                                  &error_msg));
 669     if (UNLIKELY(image_info.image_.get() == nullptr)) {
 670       LOG(ERROR) << "Failed to allocate memory for image file generation: " << error_msg;
 671       return false;
 672     }
 673
 674     // Create the image bitmap, only needs to cover mirror object section which is up to image_end_.
 675     CHECK_LE(image_info.image_end_, length);
 676     image_info.image_bitmap_.reset(gc::accounting::ContinuousSpaceBitmap::Create(
 677         "image bitmap", image_info.image_->Begin(), RoundUp(image_info.image_end_, kPageSize)));
 678     if (image_info.image_bitmap_.get() == nullptr) {
 679       LOG(ERROR) << "Failed to allocate memory for image bitmap";
 680       return false;
 681     }
 682   }
 683   return true;
 684 }
 685
 686 class ComputeLazyFieldsForClassesVisitor : public ClassVisitor {
 687  public:
 688   bool operator()(Class* c) OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
 689     StackHandleScope<1> hs(Thread::Current());
 690     mirror::Class::ComputeName(hs.NewHandle(c));
 691     return true;
 692   }
 693 };
 694
 695 void ImageWriter::ComputeLazyFieldsForImageClasses() {
 696   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
 697   ComputeLazyFieldsForClassesVisitor visitor;
 698   class_linker->VisitClassesWithoutClassesLock(&visitor);
 699 }
 700
 701 static bool IsBootClassLoaderClass(mirror::Class* klass) SHARED_REQUIRES(Locks::mutator_lock_) {
 702   return klass->GetClassLoader() == nullptr;
 703 }
 704
 705 bool ImageWriter::IsBootClassLoaderNonImageClass(mirror::Class* klass) {
 706   return IsBootClassLoaderClass(klass) && !IsInBootImage(klass);
 707 }
 708
 709 bool ImageWriter::PruneAppImageClass(mirror::Class* klass) {
 710   bool early_exit = false;
 711   std::unordered_set<mirror::Class*> visited;
 712   return PruneAppImageClassInternal(klass, &early_exit, &visited);
 713 }
 714
 715 bool ImageWriter::PruneAppImageClassInternal(
 716     mirror::Class* klass,
 717     bool* early_exit,
 718     std::unordered_set<mirror::Class*>* visited) {
 719   DCHECK(early_exit != nullptr);
 720   DCHECK(visited != nullptr);
 721   DCHECK(compile_app_image_);
 722   if (klass == nullptr || IsInBootImage(klass)) {
 723     return false;
 724   }
 725   auto found = prune_class_memo_.find(klass);
 726   if (found != prune_class_memo_.end()) {
 727     // Already computed, return the found value.
 728     return found->second;
 729   }
 730   // Circular dependencies, return false but do not store the result in the memoization table.
 731   if (visited->find(klass) != visited->end()) {
 732     *early_exit = true;
 733     return false;
 734   }
 735   visited->emplace(klass);
 736   bool result = IsBootClassLoaderClass(klass);
 737   std::string temp;
 738   // Prune if not an image class, this handles any broken sets of image classes such as having a
 739   // class in the set but not it's superclass.
 740   result = result || !compiler_driver_.IsImageClass(klass->GetDescriptor(&temp));
 741   bool my_early_exit = false;  // Only for ourselves, ignore caller.
 742   // Remove classes that failed to verify since we don't want to have java.lang.VerifyError in the
 743   // app image.
 744   if (klass->GetStatus() == mirror::Class::kStatusError) {
 745     result = true;
 746   } else {
 747     CHECK(klass->GetVerifyError() == nullptr) << PrettyClass(klass);
 748   }
 749   if (!result) {
 750     // Check interfaces since these wont be visited through VisitReferences.)
 751     mirror::IfTable* if_table = klass->GetIfTable();
 752     for (size_t i = 0, num_interfaces = klass->GetIfTableCount(); i < num_interfaces; ++i) {
 753       result = result || PruneAppImageClassInternal(if_table->GetInterface(i),
 754                                                     &my_early_exit,
 755                                                     visited);
 756     }
 757   }
 758   if (klass->IsObjectArrayClass()) {
 759     result = result || PruneAppImageClassInternal(klass->GetComponentType(),
 760                                                   &my_early_exit,
 761                                                   visited);
 762   }
 763   // Check static fields and their classes.
 764   size_t num_static_fields = klass->NumReferenceStaticFields();
 765   if (num_static_fields != 0 && klass->IsResolved()) {
 766     // Presumably GC can happen when we are cross compiling, it should not cause performance
 767     // problems to do pointer size logic.
 768     MemberOffset field_offset = klass->GetFirstReferenceStaticFieldOffset(
 769         Runtime::Current()->GetClassLinker()->GetImagePointerSize());
 770     for (size_t i = 0u; i < num_static_fields; ++i) {
 771       mirror::Object* ref = klass->GetFieldObject<mirror::Object>(field_offset);
 772       if (ref != nullptr) {
 773         if (ref->IsClass()) {
 774           result = result || PruneAppImageClassInternal(ref->AsClass(),
 775                                                         &my_early_exit,
 776                                                         visited);
 777         } else {
 778           result = result || PruneAppImageClassInternal(ref->GetClass(),
 779                                                         &my_early_exit,
 780                                                         visited);
 781         }
 782       }
 783       field_offset = MemberOffset(field_offset.Uint32Value() +
 784                                   sizeof(mirror::HeapReference<mirror::Object>));
 785     }
 786   }
 787   result = result || PruneAppImageClassInternal(klass->GetSuperClass(),
 788                                                 &my_early_exit,
 789                                                 visited);
 790   // Erase the element we stored earlier since we are exiting the function.
 791   auto it = visited->find(klass);
 792   DCHECK(it != visited->end());
 793   visited->erase(it);
 794   // Only store result if it is true or none of the calls early exited due to circular
 795   // dependencies. If visited is empty then we are the root caller, in this case the cycle was in
 796   // a child call and we can remember the result.
 797   if (result == true || !my_early_exit || visited->empty()) {
 798     prune_class_memo_[klass] = result;
 799   }
 800   *early_exit |= my_early_exit;
 801   return result;
 802 }
 803
 804 bool ImageWriter::KeepClass(Class* klass) {
 805   if (klass == nullptr) {
 806     return false;
 807   }
 808   if (compile_app_image_ && Runtime::Current()->GetHeap()->ObjectIsInBootImageSpace(klass)) {
 809     // Already in boot image, return true.
 810     return true;
 811   }
 812   std::string temp;
 813   if (!compiler_driver_.IsImageClass(klass->GetDescriptor(&temp))) {
 814     return false;
 815   }
 816   if (compile_app_image_) {
 817     // For app images, we need to prune boot loader classes that are not in the boot image since
 818     // these may have already been loaded when the app image is loaded.
 819     // Keep classes in the boot image space since we don't want to re-resolve these.
 820     return !PruneAppImageClass(klass);
 821   }
 822   return true;
 823 }
 824
 825 class NonImageClassesVisitor : public ClassVisitor {
 826  public:
 827   explicit NonImageClassesVisitor(ImageWriter* image_writer) : image_writer_(image_writer) {}
 828
 829   bool operator()(Class* klass) OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
 830     if (!image_writer_->KeepClass(klass)) {
 831       classes_to_prune_.insert(klass);
 832     }
 833     return true;
 834   }
 835
 836   std::unordered_set<mirror::Class*> classes_to_prune_;
 837   ImageWriter* const image_writer_;
 838 };
 839
 840 void ImageWriter::PruneNonImageClasses() {
 841   Runtime* runtime = Runtime::Current();
 842   ClassLinker* class_linker = runtime->GetClassLinker();
 843   Thread* self = Thread::Current();
 844
 845   // Clear class table strong roots so that dex caches can get pruned. We require pruning the class
 846   // path dex caches.
 847   class_linker->ClearClassTableStrongRoots();
 848
 849   // Make a list of classes we would like to prune.
 850   NonImageClassesVisitor visitor(this);
 851   class_linker->VisitClasses(&visitor);
 852
 853   // Remove the undesired classes from the class roots.
 854   VLOG(compiler) << "Pruning " << visitor.classes_to_prune_.size() << " classes";
 855   for (mirror::Class* klass : visitor.classes_to_prune_) {
 856     std::string temp;
 857     const char* name = klass->GetDescriptor(&temp);
 858     VLOG(compiler) << "Pruning class " << name;
 859     if (!compile_app_image_) {
 860       DCHECK(IsBootClassLoaderClass(klass));
 861     }
 862     bool result = class_linker->RemoveClass(name, klass->GetClassLoader());
 863     DCHECK(result);
 864   }
 865
 866   // Clear references to removed classes from the DexCaches.
 867   ArtMethod* resolution_method = runtime->GetResolutionMethod();
 868
 869   ScopedAssertNoThreadSuspension sa(self, __FUNCTION__);
 870   ReaderMutexLock mu(self, *Locks::classlinker_classes_lock_);  // For ClassInClassTable
 871   ReaderMutexLock mu2(self, *class_linker->DexLock());
 872   for (const ClassLinker::DexCacheData& data : class_linker->GetDexCachesData()) {
 873     if (self->IsJWeakCleared(data.weak_root)) {
 874       continue;
 875     }
 876     mirror::DexCache* dex_cache = self->DecodeJObject(data.weak_root)->AsDexCache();
 877     for (size_t i = 0; i < dex_cache->NumResolvedTypes(); i++) {
 878       Class* klass = dex_cache->GetResolvedType(i);
 879       if (klass != nullptr && !KeepClass(klass)) {
 880         dex_cache->SetResolvedType(i, nullptr);
 881       }
 882     }
 883     ArtMethod** resolved_methods = dex_cache->GetResolvedMethods();
 884     for (size_t i = 0, num = dex_cache->NumResolvedMethods(); i != num; ++i) {
 885       ArtMethod* method =
 886           mirror::DexCache::GetElementPtrSize(resolved_methods, i, target_ptr_size_);
 887       DCHECK(method != nullptr) << "Expected resolution method instead of null method";
 888       mirror::Class* declaring_class = method->GetDeclaringClass();
 889       // Copied methods may be held live by a class which was not an image class but have a
 890       // declaring class which is an image class. Set it to the resolution method to be safe and
 891       // prevent dangling pointers.
 892       if (method->IsCopied() || !KeepClass(declaring_class)) {
 893         mirror::DexCache::SetElementPtrSize(resolved_methods,
 894                                             i,
 895                                             resolution_method,
 896                                             target_ptr_size_);
 897       } else {
 898         // Check that the class is still in the classes table.
 899         DCHECK(class_linker->ClassInClassTable(declaring_class)) << "Class "
 900             << PrettyClass(declaring_class) << " not in class linker table";
 901       }
 902     }
 903     ArtField** resolved_fields = dex_cache->GetResolvedFields();
 904     for (size_t i = 0; i < dex_cache->NumResolvedFields(); i++) {
 905       ArtField* field = mirror::DexCache::GetElementPtrSize(resolved_fields, i, target_ptr_size_);
 906       if (field != nullptr && !KeepClass(field->GetDeclaringClass())) {
 907         dex_cache->SetResolvedField(i, nullptr, target_ptr_size_);
 908       }
 909     }
 910     // Clean the dex field. It might have been populated during the initialization phase, but
 911     // contains data only valid during a real run.
 912     dex_cache->SetFieldObject<false>(mirror::DexCache::DexOffset(), nullptr);
 913   }
 914
 915   // Drop the array class cache in the ClassLinker, as these are roots holding those classes live.
 916   class_linker->DropFindArrayClassCache();
 917
 918   // Clear to save RAM.
 919   prune_class_memo_.clear();
 920 }
 921
 922 void ImageWriter::CheckNonImageClassesRemoved() {
 923   if (compiler_driver_.GetImageClasses() != nullptr) {
 924     gc::Heap* heap = Runtime::Current()->GetHeap();
 925     heap->VisitObjects(CheckNonImageClassesRemovedCallback, this);
 926   }
 927 }
 928
 929 void ImageWriter::CheckNonImageClassesRemovedCallback(Object* obj, void* arg) {
 930   ImageWriter* image_writer = reinterpret_cast<ImageWriter*>(arg);
 931   if (obj->IsClass() && !image_writer->IsInBootImage(obj)) {
 932     Class* klass = obj->AsClass();
 933     if (!image_writer->KeepClass(klass)) {
 934       image_writer->DumpImageClasses();
 935       std::string temp;
 936       CHECK(image_writer->KeepClass(klass)) << klass->GetDescriptor(&temp)
 937                                             << " " << PrettyDescriptor(klass);
 938     }
 939   }
 940 }
 941
 942 void ImageWriter::DumpImageClasses() {
 943   auto image_classes = compiler_driver_.GetImageClasses();
 944   CHECK(image_classes != nullptr);
 945   for (const std::string& image_class : *image_classes) {
 946     LOG(INFO) << " " << image_class;
 947   }
 948 }
 949
 950 mirror::String* ImageWriter::FindInternedString(mirror::String* string) {
 951   Thread* const self = Thread::Current();
 952   for (const ImageInfo& image_info : image_infos_) {
 953     mirror::String* const found = image_info.intern_table_->LookupStrong(self, string);
 954     DCHECK(image_info.intern_table_->LookupWeak(self, string) == nullptr)
 955         << string->ToModifiedUtf8();
 956     if (found != nullptr) {
 957       return found;
 958     }
 959   }
 960   if (compile_app_image_) {
 961     Runtime* const runtime = Runtime::Current();
 962     mirror::String* found = runtime->GetInternTable()->LookupStrong(self, string);
 963     // If we found it in the runtime intern table it could either be in the boot image or interned
 964     // during app image compilation. If it was in the boot image return that, otherwise return null
 965     // since it belongs to another image space.
 966     if (found != nullptr && runtime->GetHeap()->ObjectIsInBootImageSpace(found)) {
 967       return found;
 968     }
 969     DCHECK(runtime->GetInternTable()->LookupWeak(self, string) == nullptr)
 970         << string->ToModifiedUtf8();
 971   }
 972   return nullptr;
 973 }
 974
 975 void ImageWriter::CalculateObjectBinSlots(Object* obj) {
 976   DCHECK(obj != nullptr);
 977   // if it is a string, we want to intern it if its not interned.
 978   if (obj->GetClass()->IsStringClass()) {
 979     size_t oat_index = GetOatIndex(obj);
 980     ImageInfo& image_info = GetImageInfo(oat_index);
 981
 982     // we must be an interned string that was forward referenced and already assigned
 983     if (IsImageBinSlotAssigned(obj)) {
 984       DCHECK_EQ(obj, FindInternedString(obj->AsString()));
 985       return;
 986     }
 987     // Need to check if the string is already interned in another image info so that we don't have
 988     // the intern tables of two different images contain the same string.
 989     mirror::String* interned = FindInternedString(obj->AsString());
 990     if (interned == nullptr) {
 991       // Not in another image space, insert to our table.
 992       interned = image_info.intern_table_->InternStrongImageString(obj->AsString());
 993     }
 994     if (obj != interned) {
 995       if (!IsImageBinSlotAssigned(interned)) {
 996         // interned obj is after us, allocate its location early
 997         AssignImageBinSlot(interned);
 998       }
 999       // point those looking for this object to the interned version.
1000       SetImageBinSlot(obj, GetImageBinSlot(interned));
1001       return;
1002     }
1003     // else (obj == interned), nothing to do but fall through to the normal case
1004   }
1005
1006   AssignImageBinSlot(obj);
1007 }
1008
1009 ObjectArray<Object>* ImageWriter::CreateImageRoots(size_t oat_index) const {
1010   Runtime* runtime = Runtime::Current();
1011   ClassLinker* class_linker = runtime->GetClassLinker();
1012   Thread* self = Thread::Current();
1013   StackHandleScope<3> hs(self);
1014   Handle<Class> object_array_class(hs.NewHandle(
1015       class_linker->FindSystemClass(self, "[Ljava/lang/Object;")));
1016
1017   std::unordered_set<const DexFile*> image_dex_files;
1018   for (auto& pair : dex_file_oat_index_map_) {
1019     const DexFile* image_dex_file = pair.first;
1020     size_t image_oat_index = pair.second;
1021     if (oat_index == image_oat_index) {
1022       image_dex_files.insert(image_dex_file);
1023     }
1024   }
1025
1026   // build an Object[] of all the DexCaches used in the source_space_.
1027   // Since we can't hold the dex lock when allocating the dex_caches
1028   // ObjectArray, we lock the dex lock twice, first to get the number
1029   // of dex caches first and then lock it again to copy the dex
1030   // caches. We check that the number of dex caches does not change.
1031   size_t dex_cache_count = 0;
1032   {
1033     ReaderMutexLock mu(self, *class_linker->DexLock());
1034     // Count number of dex caches not in the boot image.
1035     for (const ClassLinker::DexCacheData& data : class_linker->GetDexCachesData()) {
1036       mirror::DexCache* dex_cache =
1037           down_cast<mirror::DexCache*>(self->DecodeJObject(data.weak_root));
1038       if (dex_cache == nullptr) {
1039         continue;
1040       }
1041       const DexFile* dex_file = dex_cache->GetDexFile();
1042       if (!IsInBootImage(dex_cache)) {
1043         dex_cache_count += image_dex_files.find(dex_file) != image_dex_files.end() ? 1u : 0u;
1044       }
1045     }
1046   }
1047   Handle<ObjectArray<Object>> dex_caches(
1048       hs.NewHandle(ObjectArray<Object>::Alloc(self, object_array_class.Get(), dex_cache_count)));
1049   CHECK(dex_caches.Get() != nullptr) << "Failed to allocate a dex cache array.";
1050   {
1051     ReaderMutexLock mu(self, *class_linker->DexLock());
1052     size_t non_image_dex_caches = 0;
1053     // Re-count number of non image dex caches.
1054     for (const ClassLinker::DexCacheData& data : class_linker->GetDexCachesData()) {
1055       mirror::DexCache* dex_cache =
1056           down_cast<mirror::DexCache*>(self->DecodeJObject(data.weak_root));
1057       if (dex_cache == nullptr) {
1058         continue;
1059       }
1060       const DexFile* dex_file = dex_cache->GetDexFile();
1061       if (!IsInBootImage(dex_cache)) {
1062         non_image_dex_caches += image_dex_files.find(dex_file) != image_dex_files.end() ? 1u : 0u;
1063       }
1064     }
1065     CHECK_EQ(dex_cache_count, non_image_dex_caches)
1066         << "The number of non-image dex caches changed.";
1067     size_t i = 0;
1068     for (const ClassLinker::DexCacheData& data : class_linker->GetDexCachesData()) {
1069       mirror::DexCache* dex_cache =
1070           down_cast<mirror::DexCache*>(self->DecodeJObject(data.weak_root));
1071       if (dex_cache == nullptr) {
1072         continue;
1073       }
1074       const DexFile* dex_file = dex_cache->GetDexFile();
1075       if (!IsInBootImage(dex_cache) && image_dex_files.find(dex_file) != image_dex_files.end()) {
1076         dex_caches->Set<false>(i, dex_cache);
1077         ++i;
1078       }
1079     }
1080   }
1081
1082   // build an Object[] of the roots needed to restore the runtime
1083   auto image_roots(hs.NewHandle(
1084       ObjectArray<Object>::Alloc(self, object_array_class.Get(), ImageHeader::kImageRootsMax)));
1085   image_roots->Set<false>(ImageHeader::kDexCaches, dex_caches.Get());
1086   image_roots->Set<false>(ImageHeader::kClassRoots, class_linker->GetClassRoots());
1087   for (int i = 0; i < ImageHeader::kImageRootsMax; i++) {
1088     CHECK(image_roots->Get(i) != nullptr);
1089   }
1090   return image_roots.Get();
1091 }
1092
1093 // Walk instance fields of the given Class. Separate function to allow recursion on the super
1094 // class.
1095 void ImageWriter::WalkInstanceFields(mirror::Object* obj, mirror::Class* klass) {
1096   // Visit fields of parent classes first.
1097   StackHandleScope<1> hs(Thread::Current());
1098   Handle<mirror::Class> h_class(hs.NewHandle(klass));
1099   mirror::Class* super = h_class->GetSuperClass();
1100   if (super != nullptr) {
1101     WalkInstanceFields(obj, super);
1102   }
1103   //
1104   size_t num_reference_fields = h_class->NumReferenceInstanceFields();
1105   MemberOffset field_offset = h_class->GetFirstReferenceInstanceFieldOffset();
1106   for (size_t i = 0; i < num_reference_fields; ++i) {
1107     mirror::Object* value = obj->GetFieldObject<mirror::Object>(field_offset);
1108     if (value != nullptr) {
1109       WalkFieldsInOrder(value);
1110     }
1111     field_offset = MemberOffset(field_offset.Uint32Value() +
1112                                 sizeof(mirror::HeapReference<mirror::Object>));
1113   }
1114 }
1115
1116 // For an unvisited object, visit it then all its children found via fields.
1117 void ImageWriter::WalkFieldsInOrder(mirror::Object* obj) {
1118   if (IsInBootImage(obj)) {
1119     // Object is in the image, don't need to fix it up.
1120     return;
1121   }
1122   // Use our own visitor routine (instead of GC visitor) to get better locality between
1123   // an object and its fields
1124   if (!IsImageBinSlotAssigned(obj)) {
1125     // Walk instance fields of all objects
1126     StackHandleScope<2> hs(Thread::Current());
1127     Handle<mirror::Object> h_obj(hs.NewHandle(obj));
1128     Handle<mirror::Class> klass(hs.NewHandle(obj->GetClass()));
1129     // visit the object itself.
1130     CalculateObjectBinSlots(h_obj.Get());
1131     WalkInstanceFields(h_obj.Get(), klass.Get());
1132     // Walk static fields of a Class.
1133     if (h_obj->IsClass()) {
1134       size_t num_reference_static_fields = klass->NumReferenceStaticFields();
1135       MemberOffset field_offset = klass->GetFirstReferenceStaticFieldOffset(target_ptr_size_);
1136       for (size_t i = 0; i < num_reference_static_fields; ++i) {
1137         mirror::Object* value = h_obj->GetFieldObject<mirror::Object>(field_offset);
1138         if (value != nullptr) {
1139           WalkFieldsInOrder(value);
1140         }
1141         field_offset = MemberOffset(field_offset.Uint32Value() +
1142                                     sizeof(mirror::HeapReference<mirror::Object>));
1143       }
1144       // Visit and assign offsets for fields and field arrays.
1145       auto* as_klass = h_obj->AsClass();
1146       mirror::DexCache* dex_cache = as_klass->GetDexCache();
1147       DCHECK_NE(klass->GetStatus(), mirror::Class::kStatusError);
1148       if (compile_app_image_) {
1149         // Extra sanity, no boot loader classes should be left!
1150         CHECK(!IsBootClassLoaderClass(as_klass)) << PrettyClass(as_klass);
1151       }
1152       LengthPrefixedArray<ArtField>* fields[] = {
1153           as_klass->GetSFieldsPtr(), as_klass->GetIFieldsPtr(),
1154       };
1155       size_t oat_index = GetOatIndexForDexCache(dex_cache);
1156       ImageInfo& image_info = GetImageInfo(oat_index);
1157       {
1158         // Note: This table is only accessed from the image writer, so the lock is technically
1159         // unnecessary.
1160         WriterMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
1161         // Insert in the class table for this iamge.
1162         image_info.class_table_->Insert(as_klass);
1163       }
1164       for (LengthPrefixedArray<ArtField>* cur_fields : fields) {
1165         // Total array length including header.
1166         if (cur_fields != nullptr) {
1167           const size_t header_size = LengthPrefixedArray<ArtField>::ComputeSize(0);
1168           // Forward the entire array at once.
1169           auto it = native_object_relocations_.find(cur_fields);
1170           CHECK(it == native_object_relocations_.end()) << "Field array " << cur_fields
1171                                                   << " already forwarded";
1172           size_t& offset = image_info.bin_slot_sizes_[kBinArtField];
1173           DCHECK(!IsInBootImage(cur_fields));
1174           native_object_relocations_.emplace(
1175               cur_fields,
1176               NativeObjectRelocation {
1177                   oat_index, offset, kNativeObjectRelocationTypeArtFieldArray
1178               });
1179           offset += header_size;
1180           // Forward individual fields so that we can quickly find where they belong.
1181           for (size_t i = 0, count = cur_fields->size(); i < count; ++i) {
1182             // Need to forward arrays separate of fields.
1183             ArtField* field = &cur_fields->At(i);
1184             auto it2 = native_object_relocations_.find(field);
1185             CHECK(it2 == native_object_relocations_.end()) << "Field at index=" << i
1186                 << " already assigned " << PrettyField(field) << " static=" << field->IsStatic();
1187             DCHECK(!IsInBootImage(field));
1188             native_object_relocations_.emplace(
1189                 field,
1190                 NativeObjectRelocation { oat_index, offset, kNativeObjectRelocationTypeArtField });
1191             offset += sizeof(ArtField);
1192           }
1193         }
1194       }
1195       // Visit and assign offsets for methods.
1196       size_t num_methods = as_klass->NumMethods();
1197       if (num_methods != 0) {
1198         bool any_dirty = false;
1199         for (auto& m : as_klass->GetMethods(target_ptr_size_)) {
1200           if (WillMethodBeDirty(&m)) {
1201             any_dirty = true;
1202             break;
1203           }
1204         }
1205         NativeObjectRelocationType type = any_dirty
1206             ? kNativeObjectRelocationTypeArtMethodDirty
1207             : kNativeObjectRelocationTypeArtMethodClean;
1208         Bin bin_type = BinTypeForNativeRelocationType(type);
1209         // Forward the entire array at once, but header first.
1210         const size_t method_alignment = ArtMethod::Alignment(target_ptr_size_);
1211         const size_t method_size = ArtMethod::Size(target_ptr_size_);
1212         const size_t header_size = LengthPrefixedArray<ArtMethod>::ComputeSize(0,
1213                                                                                method_size,
1214                                                                                method_alignment);
1215         LengthPrefixedArray<ArtMethod>* array = as_klass->GetMethodsPtr();
1216         auto it = native_object_relocations_.find(array);
1217         CHECK(it == native_object_relocations_.end())
1218             << "Method array " << array << " already forwarded";
1219         size_t& offset = image_info.bin_slot_sizes_[bin_type];
1220         DCHECK(!IsInBootImage(array));
1221         native_object_relocations_.emplace(array,
1222             NativeObjectRelocation {
1223                 oat_index,
1224                 offset,
1225                 any_dirty ? kNativeObjectRelocationTypeArtMethodArrayDirty
1226                           : kNativeObjectRelocationTypeArtMethodArrayClean });
1227         offset += header_size;
1228         for (auto& m : as_klass->GetMethods(target_ptr_size_)) {
1229           AssignMethodOffset(&m, type, oat_index);
1230         }
1231         (any_dirty ? dirty_methods_ : clean_methods_) += num_methods;
1232       }
1233       // Assign offsets for all runtime methods in the IMT since these may hold conflict tables
1234       // live.
1235       if (as_klass->ShouldHaveImt()) {
1236         ImTable* imt = as_klass->GetImt(target_ptr_size_);
1237         for (size_t i = 0; i < ImTable::kSize; ++i) {
1238           ArtMethod* imt_method = imt->Get(i, target_ptr_size_);
1239           DCHECK(imt_method != nullptr);
1240           if (imt_method->IsRuntimeMethod() &&
1241               !IsInBootImage(imt_method) &&
1242               !NativeRelocationAssigned(imt_method)) {
1243             AssignMethodOffset(imt_method, kNativeObjectRelocationTypeRuntimeMethod, oat_index);
1244           }
1245         }
1246       }
1247
1248       if (as_klass->ShouldHaveImt()) {
1249         ImTable* imt = as_klass->GetImt(target_ptr_size_);
1250         TryAssignImTableOffset(imt, oat_index);
1251       }
1252     } else if (h_obj->IsObjectArray()) {
1253       // Walk elements of an object array.
1254       int32_t length = h_obj->AsObjectArray<mirror::Object>()->GetLength();
1255       for (int32_t i = 0; i < length; i++) {
1256         mirror::ObjectArray<mirror::Object>* obj_array = h_obj->AsObjectArray<mirror::Object>();
1257         mirror::Object* value = obj_array->Get(i);
1258         if (value != nullptr) {
1259           WalkFieldsInOrder(value);
1260         }
1261       }
1262     } else if (h_obj->IsClassLoader()) {
1263       // Register the class loader if it has a class table.
1264       // The fake boot class loader should not get registered and we should end up with only one
1265       // class loader.
1266       mirror::ClassLoader* class_loader = h_obj->AsClassLoader();
1267       if (class_loader->GetClassTable() != nullptr) {
1268         class_loaders_.insert(class_loader);
1269       }
1270     }
1271   }
1272 }
1273
1274 bool ImageWriter::NativeRelocationAssigned(void* ptr) const {
1275   return native_object_relocations_.find(ptr) != native_object_relocations_.end();
1276 }
1277
1278 void ImageWriter::TryAssignImTableOffset(ImTable* imt, size_t oat_index) {
1279   // No offset, or already assigned.
1280   if (imt == nullptr || IsInBootImage(imt) || NativeRelocationAssigned(imt)) {
1281     return;
1282   }
1283   // If the method is a conflict method we also want to assign the conflict table offset.
1284   ImageInfo& image_info = GetImageInfo(oat_index);
1285   const size_t size = ImTable::SizeInBytes(target_ptr_size_);
1286   native_object_relocations_.emplace(
1287       imt,
1288       NativeObjectRelocation {
1289           oat_index,
1290           image_info.bin_slot_sizes_[kBinImTable],
1291           kNativeObjectRelocationTypeIMTable});
1292   image_info.bin_slot_sizes_[kBinImTable] += size;
1293 }
1294
1295 void ImageWriter::TryAssignConflictTableOffset(ImtConflictTable* table, size_t oat_index) {
1296   // No offset, or already assigned.
1297   if (table == nullptr || NativeRelocationAssigned(table)) {
1298     return;
1299   }
1300   CHECK(!IsInBootImage(table));
1301   // If the method is a conflict method we also want to assign the conflict table offset.
1302   ImageInfo& image_info = GetImageInfo(oat_index);
1303   const size_t size = table->ComputeSize(target_ptr_size_);
1304   native_object_relocations_.emplace(
1305       table,
1306       NativeObjectRelocation {
1307           oat_index,
1308           image_info.bin_slot_sizes_[kBinIMTConflictTable],
1309           kNativeObjectRelocationTypeIMTConflictTable});
1310   image_info.bin_slot_sizes_[kBinIMTConflictTable] += size;
1311 }
1312
1313 void ImageWriter::AssignMethodOffset(ArtMethod* method,
1314                                      NativeObjectRelocationType type,
1315                                      size_t oat_index) {
1316   DCHECK(!IsInBootImage(method));
1317   CHECK(!NativeRelocationAssigned(method)) << "Method " << method << " already assigned "
1318       << PrettyMethod(method);
1319   if (method->IsRuntimeMethod()) {
1320     TryAssignConflictTableOffset(method->GetImtConflictTable(target_ptr_size_), oat_index);
1321   }
1322   ImageInfo& image_info = GetImageInfo(oat_index);
1323   size_t& offset = image_info.bin_slot_sizes_[BinTypeForNativeRelocationType(type)];
1324   native_object_relocations_.emplace(method, NativeObjectRelocation { oat_index, offset, type });
1325   offset += ArtMethod::Size(target_ptr_size_);
1326 }
1327
1328 void ImageWriter::WalkFieldsCallback(mirror::Object* obj, void* arg) {
1329   ImageWriter* writer = reinterpret_cast<ImageWriter*>(arg);
1330   DCHECK(writer != nullptr);
1331   writer->WalkFieldsInOrder(obj);
1332 }
1333
1334 void ImageWriter::UnbinObjectsIntoOffsetCallback(mirror::Object* obj, void* arg) {
1335   ImageWriter* writer = reinterpret_cast<ImageWriter*>(arg);
1336   DCHECK(writer != nullptr);
1337   if (!writer->IsInBootImage(obj)) {
1338     writer->UnbinObjectsIntoOffset(obj);
1339   }
1340 }
1341
1342 void ImageWriter::UnbinObjectsIntoOffset(mirror::Object* obj) {
1343   DCHECK(!IsInBootImage(obj));
1344   CHECK(obj != nullptr);
1345
1346   // We know the bin slot, and the total bin sizes for all objects by now,
1347   // so calculate the object's final image offset.
1348
1349   DCHECK(IsImageBinSlotAssigned(obj));
1350   BinSlot bin_slot = GetImageBinSlot(obj);
1351   // Change the lockword from a bin slot into an offset
1352   AssignImageOffset(obj, bin_slot);
1353 }
1354
1355 void ImageWriter::CalculateNewObjectOffsets() {
1356   Thread* const self = Thread::Current();
1357   StackHandleScopeCollection handles(self);
1358   std::vector<Handle<ObjectArray<Object>>> image_roots;
1359   for (size_t i = 0, size = oat_filenames_.size(); i != size; ++i) {
1360     image_roots.push_back(handles.NewHandle(CreateImageRoots(i)));
1361   }
1362
1363   auto* runtime = Runtime::Current();
1364   auto* heap = runtime->GetHeap();
1365
1366   // Leave space for the header, but do not write it yet, we need to
1367   // know where image_roots is going to end up
1368   image_objects_offset_begin_ = RoundUp(sizeof(ImageHeader), kObjectAlignment);  // 64-bit-alignment
1369
1370   const size_t method_alignment = ArtMethod::Alignment(target_ptr_size_);
1371   // Write the image runtime methods.
1372   image_methods_[ImageHeader::kResolutionMethod] = runtime->GetResolutionMethod();
1373   image_methods_[ImageHeader::kImtConflictMethod] = runtime->GetImtConflictMethod();
1374   image_methods_[ImageHeader::kImtUnimplementedMethod] = runtime->GetImtUnimplementedMethod();
1375   image_methods_[ImageHeader::kCalleeSaveMethod] = runtime->GetCalleeSaveMethod(Runtime::kSaveAll);
1376   image_methods_[ImageHeader::kRefsOnlySaveMethod] =
1377       runtime->GetCalleeSaveMethod(Runtime::kRefsOnly);
1378   image_methods_[ImageHeader::kRefsAndArgsSaveMethod] =
1379       runtime->GetCalleeSaveMethod(Runtime::kRefsAndArgs);
1380   // Visit image methods first to have the main runtime methods in the first image.
1381   for (auto* m : image_methods_) {
1382     CHECK(m != nullptr);
1383     CHECK(m->IsRuntimeMethod());
1384     DCHECK_EQ(compile_app_image_, IsInBootImage(m)) << "Trampolines should be in boot image";
1385     if (!IsInBootImage(m)) {
1386       AssignMethodOffset(m, kNativeObjectRelocationTypeRuntimeMethod, GetDefaultOatIndex());
1387     }
1388   }
1389
1390   // Clear any pre-existing monitors which may have been in the monitor words, assign bin slots.
1391   heap->VisitObjects(WalkFieldsCallback, this);
1392
1393   // Calculate size of the dex cache arrays slot and prepare offsets.
1394   PrepareDexCacheArraySlots();
1395
1396   // Calculate the sizes of the intern tables and class tables.
1397   for (ImageInfo& image_info : image_infos_) {
1398     // Calculate how big the intern table will be after being serialized.
1399     InternTable* const intern_table = image_info.intern_table_.get();
1400     CHECK_EQ(intern_table->WeakSize(), 0u) << " should have strong interned all the strings";
1401     image_info.intern_table_bytes_ = intern_table->WriteToMemory(nullptr);
1402     // Calculate the size of the class table.
1403     ReaderMutexLock mu(self, *Locks::classlinker_classes_lock_);
1404     image_info.class_table_bytes_ += image_info.class_table_->WriteToMemory(nullptr);
1405   }
1406
1407   // Calculate bin slot offsets.
1408   for (ImageInfo& image_info : image_infos_) {
1409     size_t bin_offset = image_objects_offset_begin_;
1410     for (size_t i = 0; i != kBinSize; ++i) {
1411       switch (i) {
1412         case kBinArtMethodClean:
1413         case kBinArtMethodDirty: {
1414           bin_offset = RoundUp(bin_offset, method_alignment);
1415           break;
1416         }
1417         case kBinImTable:
1418         case kBinIMTConflictTable: {
1419           bin_offset = RoundUp(bin_offset, target_ptr_size_);
1420           break;
1421         }
1422         default: {
1423           // Normal alignment.
1424         }
1425       }
1426       image_info.bin_slot_offsets_[i] = bin_offset;
1427       bin_offset += image_info.bin_slot_sizes_[i];
1428     }
1429     // NOTE: There may be additional padding between the bin slots and the intern table.
1430     DCHECK_EQ(image_info.image_end_,
1431               GetBinSizeSum(image_info, kBinMirrorCount) + image_objects_offset_begin_);
1432   }
1433
1434   // Calculate image offsets.
1435   size_t image_offset = 0;
1436   for (ImageInfo& image_info : image_infos_) {
1437     image_info.image_begin_ = global_image_begin_ + image_offset;
1438     image_info.image_offset_ = image_offset;
1439     ImageSection unused_sections[ImageHeader::kSectionCount];
1440     image_info.image_size_ = RoundUp(image_info.CreateImageSections(unused_sections), kPageSize);
1441     // There should be no gaps until the next image.
1442     image_offset += image_info.image_size_;
1443   }
1444
1445   // Transform each object's bin slot into an offset which will be used to do the final copy.
1446   heap->VisitObjects(UnbinObjectsIntoOffsetCallback, this);
1447
1448   // DCHECK_EQ(image_end_, GetBinSizeSum(kBinMirrorCount) + image_objects_offset_begin_);
1449
1450   size_t i = 0;
1451   for (ImageInfo& image_info : image_infos_) {
1452     image_info.image_roots_address_ = PointerToLowMemUInt32(GetImageAddress(image_roots[i].Get()));
1453     i++;
1454   }
1455
1456   // Update the native relocations by adding their bin sums.
1457   for (auto& pair : native_object_relocations_) {
1458     NativeObjectRelocation& relocation = pair.second;
1459     Bin bin_type = BinTypeForNativeRelocationType(relocation.type);
1460     ImageInfo& image_info = GetImageInfo(relocation.oat_index);
1461     relocation.offset += image_info.bin_slot_offsets_[bin_type];
1462   }
1463
1464   // Note that image_info.image_end_ is left at end of used mirror object section.
1465 }
1466
1467 size_t ImageWriter::ImageInfo::CreateImageSections(ImageSection* out_sections) const {
1468   DCHECK(out_sections != nullptr);
1469
1470   // Do not round up any sections here that are represented by the bins since it will break
1471   // offsets.
1472
1473   // Objects section
1474   ImageSection* objects_section = &out_sections[ImageHeader::kSectionObjects];
1475   *objects_section = ImageSection(0u, image_end_);
1476
1477   // Add field section.
1478   ImageSection* field_section = &out_sections[ImageHeader::kSectionArtFields];
1479   *field_section = ImageSection(bin_slot_offsets_[kBinArtField], bin_slot_sizes_[kBinArtField]);
1480   CHECK_EQ(bin_slot_offsets_[kBinArtField], field_section->Offset());
1481
1482   // Add method section.
1483   ImageSection* methods_section = &out_sections[ImageHeader::kSectionArtMethods];
1484   *methods_section = ImageSection(
1485       bin_slot_offsets_[kBinArtMethodClean],
1486       bin_slot_sizes_[kBinArtMethodClean] + bin_slot_sizes_[kBinArtMethodDirty]);
1487
1488   // IMT section.
1489   ImageSection* imt_section = &out_sections[ImageHeader::kSectionImTables];
1490   *imt_section = ImageSection(bin_slot_offsets_[kBinImTable], bin_slot_sizes_[kBinImTable]);
1491
1492   // Conflict tables section.
1493   ImageSection* imt_conflict_tables_section = &out_sections[ImageHeader::kSectionIMTConflictTables];
1494   *imt_conflict_tables_section = ImageSection(bin_slot_offsets_[kBinIMTConflictTable],
1495                                               bin_slot_sizes_[kBinIMTConflictTable]);
1496
1497   // Runtime methods section.
1498   ImageSection* runtime_methods_section = &out_sections[ImageHeader::kSectionRuntimeMethods];
1499   *runtime_methods_section = ImageSection(bin_slot_offsets_[kBinRuntimeMethod],
1500                                           bin_slot_sizes_[kBinRuntimeMethod]);
1501
1502   // Add dex cache arrays section.
1503   ImageSection* dex_cache_arrays_section = &out_sections[ImageHeader::kSectionDexCacheArrays];
1504   *dex_cache_arrays_section = ImageSection(bin_slot_offsets_[kBinDexCacheArray],
1505                                            bin_slot_sizes_[kBinDexCacheArray]);
1506
1507   // Round up to the alignment the string table expects. See HashSet::WriteToMemory.
1508   size_t cur_pos = RoundUp(dex_cache_arrays_section->End(), sizeof(uint64_t));
1509   // Calculate the size of the interned strings.
1510   ImageSection* interned_strings_section = &out_sections[ImageHeader::kSectionInternedStrings];
1511   *interned_strings_section = ImageSection(cur_pos, intern_table_bytes_);
1512   cur_pos = interned_strings_section->End();
1513   // Round up to the alignment the class table expects. See HashSet::WriteToMemory.
1514   cur_pos = RoundUp(cur_pos, sizeof(uint64_t));
1515   // Calculate the size of the class table section.
1516   ImageSection* class_table_section = &out_sections[ImageHeader::kSectionClassTable];
1517   *class_table_section = ImageSection(cur_pos, class_table_bytes_);
1518   cur_pos = class_table_section->End();
1519   // Image end goes right before the start of the image bitmap.
1520   return cur_pos;
1521 }
1522
1523 void ImageWriter::CreateHeader(size_t oat_index) {
1524   ImageInfo& image_info = GetImageInfo(oat_index);
1525   const uint8_t* oat_file_begin = image_info.oat_file_begin_;
1526   const uint8_t* oat_file_end = oat_file_begin + image_info.oat_loaded_size_;
1527   const uint8_t* oat_data_end = image_info.oat_data_begin_ + image_info.oat_size_;
1528
1529   // Create the image sections.
1530   ImageSection sections[ImageHeader::kSectionCount];
1531   const size_t image_end = image_info.CreateImageSections(sections);
1532
1533   // Finally bitmap section.
1534   const size_t bitmap_bytes = image_info.image_bitmap_->Size();
1535   auto* bitmap_section = &sections[ImageHeader::kSectionImageBitmap];
1536   *bitmap_section = ImageSection(RoundUp(image_end, kPageSize), RoundUp(bitmap_bytes, kPageSize));
1537   if (VLOG_IS_ON(compiler)) {
1538     LOG(INFO) << "Creating header for " << oat_filenames_[oat_index];
1539     size_t idx = 0;
1540     for (const ImageSection& section : sections) {
1541       LOG(INFO) << static_cast<ImageHeader::ImageSections>(idx) << " " << section;
1542       ++idx;
1543     }
1544     LOG(INFO) << "Methods: clean=" << clean_methods_ << " dirty=" << dirty_methods_;
1545     LOG(INFO) << "Image roots address=" << std::hex << image_info.image_roots_address_ << std::dec;
1546     LOG(INFO) << "Image begin=" << std::hex << reinterpret_cast<uintptr_t>(global_image_begin_)
1547               << " Image offset=" << image_info.image_offset_ << std::dec;
1548     LOG(INFO) << "Oat file begin=" << std::hex << reinterpret_cast<uintptr_t>(oat_file_begin)
1549               << " Oat data begin=" << reinterpret_cast<uintptr_t>(image_info.oat_data_begin_)
1550               << " Oat data end=" << reinterpret_cast<uintptr_t>(oat_data_end)
1551               << " Oat file end=" << reinterpret_cast<uintptr_t>(oat_file_end);
1552   }
1553   // Store boot image info for app image so that we can relocate.
1554   uint32_t boot_image_begin = 0;
1555   uint32_t boot_image_end = 0;
1556   uint32_t boot_oat_begin = 0;
1557   uint32_t boot_oat_end = 0;
1558   gc::Heap* const heap = Runtime::Current()->GetHeap();
1559   heap->GetBootImagesSize(&boot_image_begin, &boot_image_end, &boot_oat_begin, &boot_oat_end);
1560
1561   // Create the header, leave 0 for data size since we will fill this in as we are writing the
1562   // image.
1563   new (image_info.image_->Begin()) ImageHeader(PointerToLowMemUInt32(image_info.image_begin_),
1564                                                image_end,
1565                                                sections,
1566                                                image_info.image_roots_address_,
1567                                                image_info.oat_checksum_,
1568                                                PointerToLowMemUInt32(oat_file_begin),
1569                                                PointerToLowMemUInt32(image_info.oat_data_begin_),
1570                                                PointerToLowMemUInt32(oat_data_end),
1571                                                PointerToLowMemUInt32(oat_file_end),
1572                                                boot_image_begin,
1573                                                boot_image_end - boot_image_begin,
1574                                                boot_oat_begin,
1575                                                boot_oat_end - boot_oat_begin,
1576                                                target_ptr_size_,
1577                                                compile_pic_,
1578                                                /*is_pic*/compile_app_image_,
1579                                                image_storage_mode_,
1580                                                /*data_size*/0u);
1581 }
1582
1583 ArtMethod* ImageWriter::GetImageMethodAddress(ArtMethod* method) {
1584   auto it = native_object_relocations_.find(method);
1585   CHECK(it != native_object_relocations_.end()) << PrettyMethod(method) << " @ " << method;
1586   size_t oat_index = GetOatIndex(method->GetDexCache());
1587   ImageInfo& image_info = GetImageInfo(oat_index);
1588   CHECK_GE(it->second.offset, image_info.image_end_) << "ArtMethods should be after Objects";
1589   return reinterpret_cast<ArtMethod*>(image_info.image_begin_ + it->second.offset);
1590 }
1591
1592 class FixupRootVisitor : public RootVisitor {
1593  public:
1594   explicit FixupRootVisitor(ImageWriter* image_writer) : image_writer_(image_writer) {
1595   }
1596
1597   void VisitRoots(mirror::Object*** roots, size_t count, const RootInfo& info ATTRIBUTE_UNUSED)
1598       OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
1599     for (size_t i = 0; i < count; ++i) {
1600       *roots[i] = image_writer_->GetImageAddress(*roots[i]);
1601     }
1602   }
1603
1604   void VisitRoots(mirror::CompressedReference<mirror::Object>** roots, size_t count,
1605                   const RootInfo& info ATTRIBUTE_UNUSED)
1606       OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
1607     for (size_t i = 0; i < count; ++i) {
1608       roots[i]->Assign(image_writer_->GetImageAddress(roots[i]->AsMirrorPtr()));
1609     }
1610   }
1611
1612  private:
1613   ImageWriter* const image_writer_;
1614 };
1615
1616 void ImageWriter::CopyAndFixupImTable(ImTable* orig, ImTable* copy) {
1617   for (size_t i = 0; i < ImTable::kSize; ++i) {
1618     ArtMethod* method = orig->Get(i, target_ptr_size_);
1619     copy->Set(i, NativeLocationInImage(method), target_ptr_size_);
1620   }
1621 }
1622
1623 void ImageWriter::CopyAndFixupImtConflictTable(ImtConflictTable* orig, ImtConflictTable* copy) {
1624   const size_t count = orig->NumEntries(target_ptr_size_);
1625   for (size_t i = 0; i < count; ++i) {
1626     ArtMethod* interface_method = orig->GetInterfaceMethod(i, target_ptr_size_);
1627     ArtMethod* implementation_method = orig->GetImplementationMethod(i, target_ptr_size_);
1628     copy->SetInterfaceMethod(i, target_ptr_size_, NativeLocationInImage(interface_method));
1629     copy->SetImplementationMethod(i,
1630                                   target_ptr_size_,
1631                                   NativeLocationInImage(implementation_method));
1632   }
1633 }
1634
1635 void ImageWriter::CopyAndFixupNativeData(size_t oat_index) {
1636   const ImageInfo& image_info = GetImageInfo(oat_index);
1637   // Copy ArtFields and methods to their locations and update the array for convenience.
1638   for (auto& pair : native_object_relocations_) {
1639     NativeObjectRelocation& relocation = pair.second;
1640     // Only work with fields and methods that are in the current oat file.
1641     if (relocation.oat_index != oat_index) {
1642       continue;
1643     }
1644     auto* dest = image_info.image_->Begin() + relocation.offset;
1645     DCHECK_GE(dest, image_info.image_->Begin() + image_info.image_end_);
1646     DCHECK(!IsInBootImage(pair.first));
1647     switch (relocation.type) {
1648       case kNativeObjectRelocationTypeArtField: {
1649         memcpy(dest, pair.first, sizeof(ArtField));
1650         reinterpret_cast<ArtField*>(dest)->SetDeclaringClass(
1651             GetImageAddress(reinterpret_cast<ArtField*>(pair.first)->GetDeclaringClass()));
1652         break;
1653       }
1654       case kNativeObjectRelocationTypeRuntimeMethod:
1655       case kNativeObjectRelocationTypeArtMethodClean:
1656       case kNativeObjectRelocationTypeArtMethodDirty: {
1657         CopyAndFixupMethod(reinterpret_cast<ArtMethod*>(pair.first),
1658                            reinterpret_cast<ArtMethod*>(dest),
1659                            image_info);
1660         break;
1661       }
1662       // For arrays, copy just the header since the elements will get copied by their corresponding
1663       // relocations.
1664       case kNativeObjectRelocationTypeArtFieldArray: {
1665         memcpy(dest, pair.first, LengthPrefixedArray<ArtField>::ComputeSize(0));
1666         break;
1667       }
1668       case kNativeObjectRelocationTypeArtMethodArrayClean:
1669       case kNativeObjectRelocationTypeArtMethodArrayDirty: {
1670         size_t size = ArtMethod::Size(target_ptr_size_);
1671         size_t alignment = ArtMethod::Alignment(target_ptr_size_);
1672         memcpy(dest, pair.first, LengthPrefixedArray<ArtMethod>::ComputeSize(0, size, alignment));
1673         // Clear padding to avoid non-deterministic data in the image (and placate valgrind).
1674         reinterpret_cast<LengthPrefixedArray<ArtMethod>*>(dest)->ClearPadding(size, alignment);
1675         break;
1676       }
1677       case kNativeObjectRelocationTypeDexCacheArray:
1678         // Nothing to copy here, everything is done in FixupDexCache().
1679         break;
1680       case kNativeObjectRelocationTypeIMTable: {
1681         ImTable* orig_imt = reinterpret_cast<ImTable*>(pair.first);
1682         ImTable* dest_imt = reinterpret_cast<ImTable*>(dest);
1683         CopyAndFixupImTable(orig_imt, dest_imt);
1684         break;
1685       }
1686       case kNativeObjectRelocationTypeIMTConflictTable: {
1687         auto* orig_table = reinterpret_cast<ImtConflictTable*>(pair.first);
1688         CopyAndFixupImtConflictTable(
1689             orig_table,
1690             new(dest)ImtConflictTable(orig_table->NumEntries(target_ptr_size_), target_ptr_size_));
1691         break;
1692       }
1693     }
1694   }
1695   // Fixup the image method roots.
1696   auto* image_header = reinterpret_cast<ImageHeader*>(image_info.image_->Begin());
1697   for (size_t i = 0; i < ImageHeader::kImageMethodsCount; ++i) {
1698     ArtMethod* method = image_methods_[i];
1699     CHECK(method != nullptr);
1700     if (!IsInBootImage(method)) {
1701       method = NativeLocationInImage(method);
1702     }
1703     image_header->SetImageMethod(static_cast<ImageHeader::ImageMethod>(i), method);
1704   }
1705   FixupRootVisitor root_visitor(this);
1706
1707   // Write the intern table into the image.
1708   if (image_info.intern_table_bytes_ > 0) {
1709     const ImageSection& intern_table_section = image_header->GetImageSection(
1710         ImageHeader::kSectionInternedStrings);
1711     InternTable* const intern_table = image_info.intern_table_.get();
1712     uint8_t* const intern_table_memory_ptr =
1713         image_info.image_->Begin() + intern_table_section.Offset();
1714     const size_t intern_table_bytes = intern_table->WriteToMemory(intern_table_memory_ptr);
1715     CHECK_EQ(intern_table_bytes, image_info.intern_table_bytes_);
1716     // Fixup the pointers in the newly written intern table to contain image addresses.
1717     InternTable temp_intern_table;
1718     // Note that we require that ReadFromMemory does not make an internal copy of the elements so that
1719     // the VisitRoots() will update the memory directly rather than the copies.
1720     // This also relies on visit roots not doing any verification which could fail after we update
1721     // the roots to be the image addresses.
1722     temp_intern_table.AddTableFromMemory(intern_table_memory_ptr);
1723     CHECK_EQ(temp_intern_table.Size(), intern_table->Size());
1724     temp_intern_table.VisitRoots(&root_visitor, kVisitRootFlagAllRoots);
1725   }
1726   // Write the class table(s) into the image. class_table_bytes_ may be 0 if there are multiple
1727   // class loaders. Writing multiple class tables into the image is currently unsupported.
1728   if (image_info.class_table_bytes_ > 0u) {
1729     const ImageSection& class_table_section = image_header->GetImageSection(
1730         ImageHeader::kSectionClassTable);
1731     uint8_t* const class_table_memory_ptr =
1732         image_info.image_->Begin() + class_table_section.Offset();
1733     ReaderMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
1734
1735     ClassTable* table = image_info.class_table_.get();
1736     CHECK(table != nullptr);
1737     const size_t class_table_bytes = table->WriteToMemory(class_table_memory_ptr);
1738     CHECK_EQ(class_table_bytes, image_info.class_table_bytes_);
1739     // Fixup the pointers in the newly written class table to contain image addresses. See
1740     // above comment for intern tables.
1741     ClassTable temp_class_table;
1742     temp_class_table.ReadFromMemory(class_table_memory_ptr);
1743     CHECK_EQ(temp_class_table.NumZygoteClasses(), table->NumNonZygoteClasses() +
1744              table->NumZygoteClasses());
1745     BufferedRootVisitor<kDefaultBufferedRootCount> buffered_visitor(&root_visitor,
1746                                                                     RootInfo(kRootUnknown));
1747     temp_class_table.VisitRoots(buffered_visitor);
1748   }
1749 }
1750
1751 void ImageWriter::CopyAndFixupObjects() {
1752   gc::Heap* heap = Runtime::Current()->GetHeap();
1753   heap->VisitObjects(CopyAndFixupObjectsCallback, this);
1754   // Fix up the object previously had hash codes.
1755   for (const auto& hash_pair : saved_hashcode_map_) {
1756     Object* obj = hash_pair.first;
1757     DCHECK_EQ(obj->GetLockWord<kVerifyNone>(false).ReadBarrierState(), 0U);
1758     obj->SetLockWord<kVerifyNone>(LockWord::FromHashCode(hash_pair.second, 0U), false);
1759   }
1760   saved_hashcode_map_.clear();
1761 }
1762
1763 void ImageWriter::CopyAndFixupObjectsCallback(Object* obj, void* arg) {
1764   DCHECK(obj != nullptr);
1765   DCHECK(arg != nullptr);
1766   reinterpret_cast<ImageWriter*>(arg)->CopyAndFixupObject(obj);
1767 }
1768
1769 void ImageWriter::FixupPointerArray(mirror::Object* dst, mirror::PointerArray* arr,
1770                                     mirror::Class* klass, Bin array_type) {
1771   CHECK(klass->IsArrayClass());
1772   CHECK(arr->IsIntArray() || arr->IsLongArray()) << PrettyClass(klass) << " " << arr;
1773   // Fixup int and long pointers for the ArtMethod or ArtField arrays.
1774   const size_t num_elements = arr->GetLength();
1775   dst->SetClass(GetImageAddress(arr->GetClass()));
1776   auto* dest_array = down_cast<mirror::PointerArray*>(dst);
1777   for (size_t i = 0, count = num_elements; i < count; ++i) {
1778     void* elem = arr->GetElementPtrSize<void*>(i, target_ptr_size_);
1779     if (elem != nullptr && !IsInBootImage(elem)) {
1780       auto it = native_object_relocations_.find(elem);
1781       if (UNLIKELY(it == native_object_relocations_.end())) {
1782         if (it->second.IsArtMethodRelocation()) {
1783           auto* method = reinterpret_cast<ArtMethod*>(elem);
1784           LOG(FATAL) << "No relocation entry for ArtMethod " << PrettyMethod(method) << " @ "
1785               << method << " idx=" << i << "/" << num_elements << " with declaring class "
1786               << PrettyClass(method->GetDeclaringClass());
1787         } else {
1788           CHECK_EQ(array_type, kBinArtField);
1789           auto* field = reinterpret_cast<ArtField*>(elem);
1790           LOG(FATAL) << "No relocation entry for ArtField " << PrettyField(field) << " @ "
1791               << field << " idx=" << i << "/" << num_elements << " with declaring class "
1792               << PrettyClass(field->GetDeclaringClass());
1793         }
1794         UNREACHABLE();
1795       } else {
1796         ImageInfo& image_info = GetImageInfo(it->second.oat_index);
1797         elem = image_info.image_begin_ + it->second.offset;
1798       }
1799     }
1800     dest_array->SetElementPtrSize<false, true>(i, elem, target_ptr_size_);
1801   }
1802 }
1803
1804 void ImageWriter::CopyAndFixupObject(Object* obj) {
1805   if (IsInBootImage(obj)) {
1806     return;
1807   }
1808   size_t offset = GetImageOffset(obj);
1809   size_t oat_index = GetOatIndex(obj);
1810   ImageInfo& image_info = GetImageInfo(oat_index);
1811   auto* dst = reinterpret_cast<Object*>(image_info.image_->Begin() + offset);
1812   DCHECK_LT(offset, image_info.image_end_);
1813   const auto* src = reinterpret_cast<const uint8_t*>(obj);
1814
1815   image_info.image_bitmap_->Set(dst);  // Mark the obj as live.
1816
1817   const size_t n = obj->SizeOf();
1818   DCHECK_LE(offset + n, image_info.image_->Size());
1819   memcpy(dst, src, n);
1820
1821   // Write in a hash code of objects which have inflated monitors or a hash code in their monitor
1822   // word.
1823   const auto it = saved_hashcode_map_.find(obj);
1824   dst->SetLockWord(it != saved_hashcode_map_.end() ?
1825       LockWord::FromHashCode(it->second, 0u) : LockWord::Default(), false);
1826   FixupObject(obj, dst);
1827 }
1828
1829 // Rewrite all the references in the copied object to point to their image address equivalent
1830 class FixupVisitor {
1831  public:
1832   FixupVisitor(ImageWriter* image_writer, Object* copy) : image_writer_(image_writer), copy_(copy) {
1833   }
1834
1835   // Ignore class roots since we don't have a way to map them to the destination. These are handled
1836   // with other logic.
1837   void VisitRootIfNonNull(mirror::CompressedReference<mirror::Object>* root ATTRIBUTE_UNUSED)
1838       const {}
1839   void VisitRoot(mirror::CompressedReference<mirror::Object>* root ATTRIBUTE_UNUSED) const {}
1840
1841
1842   void operator()(Object* obj, MemberOffset offset, bool is_static ATTRIBUTE_UNUSED) const
1843       REQUIRES(Locks::mutator_lock_, Locks::heap_bitmap_lock_) {
1844     Object* ref = obj->GetFieldObject<Object, kVerifyNone>(offset);
1845     // Use SetFieldObjectWithoutWriteBarrier to avoid card marking since we are writing to the
1846     // image.
1847     copy_->SetFieldObjectWithoutWriteBarrier<false, true, kVerifyNone>(
1848         offset,
1849         image_writer_->GetImageAddress(ref));
1850   }
1851
1852   // java.lang.ref.Reference visitor.
1853   void operator()(mirror::Class* klass ATTRIBUTE_UNUSED, mirror::Reference* ref) const
1854       SHARED_REQUIRES(Locks::mutator_lock_) REQUIRES(Locks::heap_bitmap_lock_) {
1855     copy_->SetFieldObjectWithoutWriteBarrier<false, true, kVerifyNone>(
1856         mirror::Reference::ReferentOffset(),
1857         image_writer_->GetImageAddress(ref->GetReferent()));
1858   }
1859
1860  protected:
1861   ImageWriter* const image_writer_;
1862   mirror::Object* const copy_;
1863 };
1864
1865 class FixupClassVisitor FINAL : public FixupVisitor {
1866  public:
1867   FixupClassVisitor(ImageWriter* image_writer, Object* copy) : FixupVisitor(image_writer, copy) {
1868   }
1869
1870   void operator()(Object* obj, MemberOffset offset, bool is_static ATTRIBUTE_UNUSED) const
1871       REQUIRES(Locks::mutator_lock_, Locks::heap_bitmap_lock_) {
1872     DCHECK(obj->IsClass());
1873     FixupVisitor::operator()(obj, offset, /*is_static*/false);
1874   }
1875
1876   void operator()(mirror::Class* klass ATTRIBUTE_UNUSED,
1877                   mirror::Reference* ref ATTRIBUTE_UNUSED) const
1878       SHARED_REQUIRES(Locks::mutator_lock_) REQUIRES(Locks::heap_bitmap_lock_) {
1879     LOG(FATAL) << "Reference not expected here.";
1880   }
1881 };
1882
1883 uintptr_t ImageWriter::NativeOffsetInImage(void* obj) {
1884   DCHECK(obj != nullptr);
1885   DCHECK(!IsInBootImage(obj));
1886   auto it = native_object_relocations_.find(obj);
1887   CHECK(it != native_object_relocations_.end()) << obj << " spaces "
1888       << Runtime::Current()->GetHeap()->DumpSpaces();
1889   const NativeObjectRelocation& relocation = it->second;
1890   return relocation.offset;
1891 }
1892
1893 template <typename T>
1894 std::string PrettyPrint(T* ptr) SHARED_REQUIRES(Locks::mutator_lock_) {
1895   std::ostringstream oss;
1896   oss << ptr;
1897   return oss.str();
1898 }
1899
1900 template <>
1901 std::string PrettyPrint(ArtMethod* method) SHARED_REQUIRES(Locks::mutator_lock_) {
1902   return PrettyMethod(method);
1903 }
1904
1905 template <typename T>
1906 T* ImageWriter::NativeLocationInImage(T* obj) {
1907   if (obj == nullptr || IsInBootImage(obj)) {
1908     return obj;
1909   } else {
1910     auto it = native_object_relocations_.find(obj);
1911     CHECK(it != native_object_relocations_.end()) << obj << " " << PrettyPrint(obj)
1912         << " spaces " << Runtime::Current()->GetHeap()->DumpSpaces();
1913     const NativeObjectRelocation& relocation = it->second;
1914     ImageInfo& image_info = GetImageInfo(relocation.oat_index);
1915     return reinterpret_cast<T*>(image_info.image_begin_ + relocation.offset);
1916   }
1917 }
1918
1919 template <typename T>
1920 T* ImageWriter::NativeCopyLocation(T* obj, mirror::DexCache* dex_cache) {
1921   if (obj == nullptr || IsInBootImage(obj)) {
1922     return obj;
1923   } else {
1924     size_t oat_index = GetOatIndexForDexCache(dex_cache);
1925     ImageInfo& image_info = GetImageInfo(oat_index);
1926     return reinterpret_cast<T*>(image_info.image_->Begin() + NativeOffsetInImage(obj));
1927   }
1928 }
1929
1930 class NativeLocationVisitor {
1931  public:
1932   explicit NativeLocationVisitor(ImageWriter* image_writer) : image_writer_(image_writer) {}
1933
1934   template <typename T>
1935   T* operator()(T* ptr) const SHARED_REQUIRES(Locks::mutator_lock_) {
1936     return image_writer_->NativeLocationInImage(ptr);
1937   }
1938
1939  private:
1940   ImageWriter* const image_writer_;
1941 };
1942
1943 void ImageWriter::FixupClass(mirror::Class* orig, mirror::Class* copy) {
1944   orig->FixupNativePointers(copy, target_ptr_size_, NativeLocationVisitor(this));
1945   FixupClassVisitor visitor(this, copy);
1946   static_cast<mirror::Object*>(orig)->VisitReferences(visitor, visitor);
1947
1948   // Remove the clinitThreadId. This is required for image determinism.
1949   copy->SetClinitThreadId(static_cast<pid_t>(0));
1950 }
1951
1952 void ImageWriter::FixupObject(Object* orig, Object* copy) {
1953   DCHECK(orig != nullptr);
1954   DCHECK(copy != nullptr);
1955   if (kUseBakerOrBrooksReadBarrier) {
1956     orig->AssertReadBarrierPointer();
1957     if (kUseBrooksReadBarrier) {
1958       // Note the address 'copy' isn't the same as the image address of 'orig'.
1959       copy->SetReadBarrierPointer(GetImageAddress(orig));
1960       DCHECK_EQ(copy->GetReadBarrierPointer(), GetImageAddress(orig));
1961     }
1962   }
1963   auto* klass = orig->GetClass();
1964   if (klass->IsIntArrayClass() || klass->IsLongArrayClass()) {
1965     // Is this a native pointer array?
1966     auto it = pointer_arrays_.find(down_cast<mirror::PointerArray*>(orig));
1967     if (it != pointer_arrays_.end()) {
1968       // Should only need to fixup every pointer array exactly once.
1969       FixupPointerArray(copy, down_cast<mirror::PointerArray*>(orig), klass, it->second);
1970       pointer_arrays_.erase(it);
1971       return;
1972     }
1973   }
1974   if (orig->IsClass()) {
1975     FixupClass(orig->AsClass<kVerifyNone>(), down_cast<mirror::Class*>(copy));
1976   } else {
1977     if (klass == mirror::Method::StaticClass() || klass == mirror::Constructor::StaticClass()) {
1978       // Need to go update the ArtMethod.
1979       auto* dest = down_cast<mirror::AbstractMethod*>(copy);
1980       auto* src = down_cast<mirror::AbstractMethod*>(orig);
1981       ArtMethod* src_method = src->GetArtMethod();
1982       auto it = native_object_relocations_.find(src_method);
1983       CHECK(it != native_object_relocations_.end())
1984           << "Missing relocation for AbstractMethod.artMethod " << PrettyMethod(src_method);
1985       dest->SetArtMethod(
1986           reinterpret_cast<ArtMethod*>(global_image_begin_ + it->second.offset));
1987     } else if (!klass->IsArrayClass()) {
1988       ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
1989       if (klass == class_linker->GetClassRoot(ClassLinker::kJavaLangDexCache)) {
1990         FixupDexCache(down_cast<mirror::DexCache*>(orig), down_cast<mirror::DexCache*>(copy));
1991       } else if (klass->IsClassLoaderClass()) {
1992         mirror::ClassLoader* copy_loader = down_cast<mirror::ClassLoader*>(copy);
1993         // If src is a ClassLoader, set the class table to null so that it gets recreated by the
1994         // ClassLoader.
1995         copy_loader->SetClassTable(nullptr);
1996         // Also set allocator to null to be safe. The allocator is created when we create the class
1997         // table. We also never expect to unload things in the image since they are held live as
1998         // roots.
1999         copy_loader->SetAllocator(nullptr);
2000       }
2001     }
2002     FixupVisitor visitor(this, copy);
2003     orig->VisitReferences(visitor, visitor);
2004   }
2005 }
2006
2007
2008 class ImageAddressVisitor {
2009  public:
2010   explicit ImageAddressVisitor(ImageWriter* image_writer) : image_writer_(image_writer) {}
2011
2012   template <typename T>
2013   T* operator()(T* ptr) const SHARED_REQUIRES(Locks::mutator_lock_) {
2014     return image_writer_->GetImageAddress(ptr);
2015   }
2016
2017  private:
2018   ImageWriter* const image_writer_;
2019 };
2020
2021
2022 void ImageWriter::FixupDexCache(mirror::DexCache* orig_dex_cache,
2023                                 mirror::DexCache* copy_dex_cache) {
2024   // Though the DexCache array fields are usually treated as native pointers, we set the full
2025   // 64-bit values here, clearing the top 32 bits for 32-bit targets. The zero-extension is
2026   // done by casting to the unsigned type uintptr_t before casting to int64_t, i.e.
2027   //     static_cast<int64_t>(reinterpret_cast<uintptr_t>(image_begin_ + offset))).
2028   GcRoot<mirror::String>* orig_strings = orig_dex_cache->GetStrings();
2029   if (orig_strings != nullptr) {
2030     copy_dex_cache->SetFieldPtrWithSize<false>(mirror::DexCache::StringsOffset(),
2031                                                NativeLocationInImage(orig_strings),
2032                                                /*pointer size*/8u);
2033     orig_dex_cache->FixupStrings(NativeCopyLocation(orig_strings, orig_dex_cache),
2034                                  ImageAddressVisitor(this));
2035   }
2036   GcRoot<mirror::Class>* orig_types = orig_dex_cache->GetResolvedTypes();
2037   if (orig_types != nullptr) {
2038     copy_dex_cache->SetFieldPtrWithSize<false>(mirror::DexCache::ResolvedTypesOffset(),
2039                                                NativeLocationInImage(orig_types),
2040                                                /*pointer size*/8u);
2041     orig_dex_cache->FixupResolvedTypes(NativeCopyLocation(orig_types, orig_dex_cache),
2042                                        ImageAddressVisitor(this));
2043   }
2044   ArtMethod** orig_methods = orig_dex_cache->GetResolvedMethods();
2045   if (orig_methods != nullptr) {
2046     copy_dex_cache->SetFieldPtrWithSize<false>(mirror::DexCache::ResolvedMethodsOffset(),
2047                                                NativeLocationInImage(orig_methods),
2048                                                /*pointer size*/8u);
2049     ArtMethod** copy_methods = NativeCopyLocation(orig_methods, orig_dex_cache);
2050     for (size_t i = 0, num = orig_dex_cache->NumResolvedMethods(); i != num; ++i) {
2051       ArtMethod* orig = mirror::DexCache::GetElementPtrSize(orig_methods, i, target_ptr_size_);
2052       // NativeLocationInImage also handles runtime methods since these have relocation info.
2053       ArtMethod* copy = NativeLocationInImage(orig);
2054       mirror::DexCache::SetElementPtrSize(copy_methods, i, copy, target_ptr_size_);
2055     }
2056   }
2057   ArtField** orig_fields = orig_dex_cache->GetResolvedFields();
2058   if (orig_fields != nullptr) {
2059     copy_dex_cache->SetFieldPtrWithSize<false>(mirror::DexCache::ResolvedFieldsOffset(),
2060                                                NativeLocationInImage(orig_fields),
2061                                                /*pointer size*/8u);
2062     ArtField** copy_fields = NativeCopyLocation(orig_fields, orig_dex_cache);
2063     for (size_t i = 0, num = orig_dex_cache->NumResolvedFields(); i != num; ++i) {
2064       ArtField* orig = mirror::DexCache::GetElementPtrSize(orig_fields, i, target_ptr_size_);
2065       ArtField* copy = NativeLocationInImage(orig);
2066       mirror::DexCache::SetElementPtrSize(copy_fields, i, copy, target_ptr_size_);
2067     }
2068   }
2069
2070   // Remove the DexFile pointers. They will be fixed up when the runtime loads the oat file. Leaving
2071   // compiler pointers in here will make the output non-deterministic.
2072   copy_dex_cache->SetDexFile(nullptr);
2073 }
2074
2075 const uint8_t* ImageWriter::GetOatAddress(OatAddress type) const {
2076   DCHECK_LT(type, kOatAddressCount);
2077   // If we are compiling an app image, we need to use the stubs of the boot image.
2078   if (compile_app_image_) {
2079     // Use the current image pointers.
2080     const std::vector<gc::space::ImageSpace*>& image_spaces =
2081         Runtime::Current()->GetHeap()->GetBootImageSpaces();
2082     DCHECK(!image_spaces.empty());
2083     const OatFile* oat_file = image_spaces[0]->GetOatFile();
2084     CHECK(oat_file != nullptr);
2085     const OatHeader& header = oat_file->GetOatHeader();
2086     switch (type) {
2087       // TODO: We could maybe clean this up if we stored them in an array in the oat header.
2088       case kOatAddressQuickGenericJNITrampoline:
2089         return static_cast<const uint8_t*>(header.GetQuickGenericJniTrampoline());
2090       case kOatAddressInterpreterToInterpreterBridge:
2091         return static_cast<const uint8_t*>(header.GetInterpreterToInterpreterBridge());
2092       case kOatAddressInterpreterToCompiledCodeBridge:
2093         return static_cast<const uint8_t*>(header.GetInterpreterToCompiledCodeBridge());
2094       case kOatAddressJNIDlsymLookup:
2095         return static_cast<const uint8_t*>(header.GetJniDlsymLookup());
2096       case kOatAddressQuickIMTConflictTrampoline:
2097         return static_cast<const uint8_t*>(header.GetQuickImtConflictTrampoline());
2098       case kOatAddressQuickResolutionTrampoline:
2099         return static_cast<const uint8_t*>(header.GetQuickResolutionTrampoline());
2100       case kOatAddressQuickToInterpreterBridge:
2101         return static_cast<const uint8_t*>(header.GetQuickToInterpreterBridge());
2102       default:
2103         UNREACHABLE();
2104     }
2105   }
2106   const ImageInfo& primary_image_info = GetImageInfo(0);
2107   return GetOatAddressForOffset(primary_image_info.oat_address_offsets_[type], primary_image_info);
2108 }
2109
2110 const uint8_t* ImageWriter::GetQuickCode(ArtMethod* method,
2111                                          const ImageInfo& image_info,
2112                                          bool* quick_is_interpreted) {
2113   DCHECK(!method->IsResolutionMethod()) << PrettyMethod(method);
2114   DCHECK_NE(method, Runtime::Current()->GetImtConflictMethod()) << PrettyMethod(method);
2115   DCHECK(!method->IsImtUnimplementedMethod()) << PrettyMethod(method);
2116   DCHECK(method->IsInvokable()) << PrettyMethod(method);
2117   DCHECK(!IsInBootImage(method)) << PrettyMethod(method);
2118
2119   // Use original code if it exists. Otherwise, set the code pointer to the resolution
2120   // trampoline.
2121
2122   // Quick entrypoint:
2123   const void* quick_oat_entry_point =
2124       method->GetEntryPointFromQuickCompiledCodePtrSize(target_ptr_size_);
2125   const uint8_t* quick_code;
2126
2127   if (UNLIKELY(IsInBootImage(method->GetDeclaringClass()))) {
2128     DCHECK(method->IsCopied());
2129     // If the code is not in the oat file corresponding to this image (e.g. default methods)
2130     quick_code = reinterpret_cast<const uint8_t*>(quick_oat_entry_point);
2131   } else {
2132     uint32_t quick_oat_code_offset = PointerToLowMemUInt32(quick_oat_entry_point);
2133     quick_code = GetOatAddressForOffset(quick_oat_code_offset, image_info);
2134   }
2135
2136   *quick_is_interpreted = false;
2137   if (quick_code != nullptr && (!method->IsStatic() || method->IsConstructor() ||
2138       method->GetDeclaringClass()->IsInitialized())) {
2139     // We have code for a non-static or initialized method, just use the code.
2140   } else if (quick_code == nullptr && method->IsNative() &&
2141       (!method->IsStatic() || method->GetDeclaringClass()->IsInitialized())) {
2142     // Non-static or initialized native method missing compiled code, use generic JNI version.
2143     quick_code = GetOatAddress(kOatAddressQuickGenericJNITrampoline);
2144   } else if (quick_code == nullptr && !method->IsNative()) {
2145     // We don't have code at all for a non-native method, use the interpreter.
2146     quick_code = GetOatAddress(kOatAddressQuickToInterpreterBridge);
2147     *quick_is_interpreted = true;
2148   } else {
2149     CHECK(!method->GetDeclaringClass()->IsInitialized());
2150     // We have code for a static method, but need to go through the resolution stub for class
2151     // initialization.
2152     quick_code = GetOatAddress(kOatAddressQuickResolutionTrampoline);
2153   }
2154   if (!IsInBootOatFile(quick_code)) {
2155     // DCHECK_GE(quick_code, oat_data_begin_);
2156   }
2157   return quick_code;
2158 }
2159
2160 void ImageWriter::CopyAndFixupMethod(ArtMethod* orig,
2161                                      ArtMethod* copy,
2162                                      const ImageInfo& image_info) {
2163   memcpy(copy, orig, ArtMethod::Size(target_ptr_size_));
2164
2165   copy->SetDeclaringClass(GetImageAddress(orig->GetDeclaringClassUnchecked()));
2166   ArtMethod** orig_resolved_methods = orig->GetDexCacheResolvedMethods(target_ptr_size_);
2167   copy->SetDexCacheResolvedMethods(NativeLocationInImage(orig_resolved_methods), target_ptr_size_);
2168   GcRoot<mirror::Class>* orig_resolved_types = orig->GetDexCacheResolvedTypes(target_ptr_size_);
2169   copy->SetDexCacheResolvedTypes(NativeLocationInImage(orig_resolved_types), target_ptr_size_);
2170
2171   // OatWriter replaces the code_ with an offset value. Here we re-adjust to a pointer relative to
2172   // oat_begin_
2173
2174   // The resolution method has a special trampoline to call.
2175   Runtime* runtime = Runtime::Current();
2176   if (orig->IsRuntimeMethod()) {
2177     ImtConflictTable* orig_table = orig->GetImtConflictTable(target_ptr_size_);
2178     if (orig_table != nullptr) {
2179       // Special IMT conflict method, normal IMT conflict method or unimplemented IMT method.
2180       copy->SetEntryPointFromQuickCompiledCodePtrSize(
2181           GetOatAddress(kOatAddressQuickIMTConflictTrampoline), target_ptr_size_);
2182       copy->SetImtConflictTable(NativeLocationInImage(orig_table), target_ptr_size_);
2183     } else if (UNLIKELY(orig == runtime->GetResolutionMethod())) {
2184       copy->SetEntryPointFromQuickCompiledCodePtrSize(
2185           GetOatAddress(kOatAddressQuickResolutionTrampoline), target_ptr_size_);
2186     } else {
2187       bool found_one = false;
2188       for (size_t i = 0; i < static_cast<size_t>(Runtime::kLastCalleeSaveType); ++i) {
2189         auto idx = static_cast<Runtime::CalleeSaveType>(i);
2190         if (runtime->HasCalleeSaveMethod(idx) && runtime->GetCalleeSaveMethod(idx) == orig) {
2191           found_one = true;
2192           break;
2193         }
2194       }
2195       CHECK(found_one) << "Expected to find callee save method but got " << PrettyMethod(orig);
2196       CHECK(copy->IsRuntimeMethod());
2197     }
2198   } else {
2199     // We assume all methods have code. If they don't currently then we set them to the use the
2200     // resolution trampoline. Abstract methods never have code and so we need to make sure their
2201     // use results in an AbstractMethodError. We use the interpreter to achieve this.
2202     if (UNLIKELY(!orig->IsInvokable())) {
2203       copy->SetEntryPointFromQuickCompiledCodePtrSize(
2204           GetOatAddress(kOatAddressQuickToInterpreterBridge), target_ptr_size_);
2205     } else {
2206       bool quick_is_interpreted;
2207       const uint8_t* quick_code = GetQuickCode(orig, image_info, &quick_is_interpreted);
2208       copy->SetEntryPointFromQuickCompiledCodePtrSize(quick_code, target_ptr_size_);
2209
2210       // JNI entrypoint:
2211       if (orig->IsNative()) {
2212         // The native method's pointer is set to a stub to lookup via dlsym.
2213         // Note this is not the code_ pointer, that is handled above.
2214         copy->SetEntryPointFromJniPtrSize(
2215             GetOatAddress(kOatAddressJNIDlsymLookup), target_ptr_size_);
2216       }
2217     }
2218   }
2219 }
2220
2221 size_t ImageWriter::GetBinSizeSum(ImageWriter::ImageInfo& image_info, ImageWriter::Bin up_to) const {
2222   DCHECK_LE(up_to, kBinSize);
2223   return std::accumulate(&image_info.bin_slot_sizes_[0],
2224                          &image_info.bin_slot_sizes_[up_to],
2225                          /*init*/0);
2226 }
2227
2228 ImageWriter::BinSlot::BinSlot(uint32_t lockword) : lockword_(lockword) {
2229   // These values may need to get updated if more bins are added to the enum Bin
2230   static_assert(kBinBits == 3, "wrong number of bin bits");
2231   static_assert(kBinShift == 27, "wrong number of shift");
2232   static_assert(sizeof(BinSlot) == sizeof(LockWord), "BinSlot/LockWord must have equal sizes");
2233
2234   DCHECK_LT(GetBin(), kBinSize);
2235   DCHECK_ALIGNED(GetIndex(), kObjectAlignment);
2236 }
2237
2238 ImageWriter::BinSlot::BinSlot(Bin bin, uint32_t index)
2239     : BinSlot(index | (static_cast<uint32_t>(bin) << kBinShift)) {
2240   DCHECK_EQ(index, GetIndex());
2241 }
2242
2243 ImageWriter::Bin ImageWriter::BinSlot::GetBin() const {
2244   return static_cast<Bin>((lockword_ & kBinMask) >> kBinShift);
2245 }
2246
2247 uint32_t ImageWriter::BinSlot::GetIndex() const {
2248   return lockword_ & ~kBinMask;
2249 }
2250
2251 ImageWriter::Bin ImageWriter::BinTypeForNativeRelocationType(NativeObjectRelocationType type) {
2252   switch (type) {
2253     case kNativeObjectRelocationTypeArtField:
2254     case kNativeObjectRelocationTypeArtFieldArray:
2255       return kBinArtField;
2256     case kNativeObjectRelocationTypeArtMethodClean:
2257     case kNativeObjectRelocationTypeArtMethodArrayClean:
2258       return kBinArtMethodClean;
2259     case kNativeObjectRelocationTypeArtMethodDirty:
2260     case kNativeObjectRelocationTypeArtMethodArrayDirty:
2261       return kBinArtMethodDirty;
2262     case kNativeObjectRelocationTypeDexCacheArray:
2263       return kBinDexCacheArray;
2264     case kNativeObjectRelocationTypeRuntimeMethod:
2265       return kBinRuntimeMethod;
2266     case kNativeObjectRelocationTypeIMTable:
2267       return kBinImTable;
2268     case kNativeObjectRelocationTypeIMTConflictTable:
2269       return kBinIMTConflictTable;
2270   }
2271   UNREACHABLE();
2272 }
2273
2274 size_t ImageWriter::GetOatIndex(mirror::Object* obj) const {
2275   if (compile_app_image_) {
2276     return GetDefaultOatIndex();
2277   } else {
2278     mirror::DexCache* dex_cache =
2279         obj->IsDexCache() ? obj->AsDexCache()
2280                           : obj->IsClass() ? obj->AsClass()->GetDexCache()
2281                                            : obj->GetClass()->GetDexCache();
2282     return GetOatIndexForDexCache(dex_cache);
2283   }
2284 }
2285
2286 size_t ImageWriter::GetOatIndexForDexFile(const DexFile* dex_file) const {
2287   if (compile_app_image_) {
2288     return GetDefaultOatIndex();
2289   } else {
2290     auto it = dex_file_oat_index_map_.find(dex_file);
2291     DCHECK(it != dex_file_oat_index_map_.end()) << dex_file->GetLocation();
2292     return it->second;
2293   }
2294 }
2295
2296 size_t ImageWriter::GetOatIndexForDexCache(mirror::DexCache* dex_cache) const {
2297   if (dex_cache == nullptr) {
2298     return GetDefaultOatIndex();
2299   } else {
2300     return GetOatIndexForDexFile(dex_cache->GetDexFile());
2301   }
2302 }
2303
2304 void ImageWriter::UpdateOatFileLayout(size_t oat_index,
2305                                       size_t oat_loaded_size,
2306                                       size_t oat_data_offset,
2307                                       size_t oat_data_size) {
2308   const uint8_t* images_end = image_infos_.back().image_begin_ + image_infos_.back().image_size_;
2309   for (const ImageInfo& info : image_infos_) {
2310     DCHECK_LE(info.image_begin_ + info.image_size_, images_end);
2311   }
2312   DCHECK(images_end != nullptr);  // Image space must be ready.
2313
2314   ImageInfo& cur_image_info = GetImageInfo(oat_index);
2315   cur_image_info.oat_file_begin_ = images_end + cur_image_info.oat_offset_;
2316   cur_image_info.oat_loaded_size_ = oat_loaded_size;
2317   cur_image_info.oat_data_begin_ = cur_image_info.oat_file_begin_ + oat_data_offset;
2318   cur_image_info.oat_size_ = oat_data_size;
2319
2320   if (compile_app_image_) {
2321     CHECK_EQ(oat_filenames_.size(), 1u) << "App image should have no next image.";
2322     return;
2323   }
2324
2325   // Update the oat_offset of the next image info.
2326   if (oat_index + 1u != oat_filenames_.size()) {
2327     // There is a following one.
2328     ImageInfo& next_image_info = GetImageInfo(oat_index + 1u);
2329     next_image_info.oat_offset_ = cur_image_info.oat_offset_ + oat_loaded_size;
2330   }
2331 }
2332
2333 void ImageWriter::UpdateOatFileHeader(size_t oat_index, const OatHeader& oat_header) {
2334   ImageInfo& cur_image_info = GetImageInfo(oat_index);
2335   cur_image_info.oat_checksum_ = oat_header.GetChecksum();
2336
2337   if (oat_index == GetDefaultOatIndex()) {
2338     // Primary oat file, read the trampolines.
2339     cur_image_info.oat_address_offsets_[kOatAddressInterpreterToInterpreterBridge] =
2340         oat_header.GetInterpreterToInterpreterBridgeOffset();
2341     cur_image_info.oat_address_offsets_[kOatAddressInterpreterToCompiledCodeBridge] =
2342         oat_header.GetInterpreterToCompiledCodeBridgeOffset();
2343     cur_image_info.oat_address_offsets_[kOatAddressJNIDlsymLookup] =
2344         oat_header.GetJniDlsymLookupOffset();
2345     cur_image_info.oat_address_offsets_[kOatAddressQuickGenericJNITrampoline] =
2346         oat_header.GetQuickGenericJniTrampolineOffset();
2347     cur_image_info.oat_address_offsets_[kOatAddressQuickIMTConflictTrampoline] =
2348         oat_header.GetQuickImtConflictTrampolineOffset();
2349     cur_image_info.oat_address_offsets_[kOatAddressQuickResolutionTrampoline] =
2350         oat_header.GetQuickResolutionTrampolineOffset();
2351     cur_image_info.oat_address_offsets_[kOatAddressQuickToInterpreterBridge] =
2352         oat_header.GetQuickToInterpreterBridgeOffset();
2353   }
2354 }
2355
2356 ImageWriter::ImageWriter(
2357     const CompilerDriver& compiler_driver,
2358     uintptr_t image_begin,
2359     bool compile_pic,
2360     bool compile_app_image,
2361     ImageHeader::StorageMode image_storage_mode,
2362     const std::vector<const char*>& oat_filenames,
2363     const std::unordered_map<const DexFile*, size_t>& dex_file_oat_index_map)
2364     : compiler_driver_(compiler_driver),
2365       global_image_begin_(reinterpret_cast<uint8_t*>(image_begin)),
2366       image_objects_offset_begin_(0),
2367       compile_pic_(compile_pic),
2368       compile_app_image_(compile_app_image),
2369       target_ptr_size_(InstructionSetPointerSize(compiler_driver_.GetInstructionSet())),
2370       image_infos_(oat_filenames.size()),
2371       dirty_methods_(0u),
2372       clean_methods_(0u),
2373       image_storage_mode_(image_storage_mode),
2374       oat_filenames_(oat_filenames),
2375       dex_file_oat_index_map_(dex_file_oat_index_map) {
2376   CHECK_NE(image_begin, 0U);
2377   std::fill_n(image_methods_, arraysize(image_methods_), nullptr);
2378   CHECK_EQ(compile_app_image, !Runtime::Current()->GetHeap()->GetBootImageSpaces().empty())
2379       << "Compiling a boot image should occur iff there are no boot image spaces loaded";
2380 }
2381
2382 ImageWriter::ImageInfo::ImageInfo()
2383     : intern_table_(new InternTable),
2384       class_table_(new ClassTable) {}
2385
2386 }  // namespace art