compiler/image_writer.cc

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