compiler/image_writer.cc

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