/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include "base/memory_tool.h"

#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <unordered_set>
#include <vector>

#if defined(__linux__) && defined(__arm__)
#include <sys/personality.h>
#include <sys/utsname.h>
#endif

#define ATRACE_TAG ATRACE_TAG_DALVIK
#include <cutils/trace.h>

#include "art_method-inl.h"
#include "arch/instruction_set_features.h"
#include "arch/mips/instruction_set_features_mips.h"
#include "base/dumpable.h"
#include "base/macros.h"
#include "base/stl_util.h"
#include "base/stringpiece.h"
#include "base/time_utils.h"
#include "base/timing_logger.h"
#include "base/unix_file/fd_file.h"
#include "class_linker.h"
#include "compiler.h"
#include "compiler_callbacks.h"
#include "dex_file-inl.h"
#include "dex/pass_manager.h"
#include "dex/verification_results.h"
#include "dex/quick_compiler_callbacks.h"
#include "dex/quick/dex_file_to_method_inliner_map.h"
#include "driver/compiler_driver.h"
#include "driver/compiler_options.h"
#include "dwarf/method_debug_info.h"
#include "elf_file.h"
#include "elf_writer.h"
#include "elf_writer_quick.h"
#include "gc/space/image_space.h"
#include "gc/space/space-inl.h"
#include "image_writer.h"
#include "interpreter/unstarted_runtime.h"
#include "leb128.h"
#include "mirror/class-inl.h"
#include "mirror/class_loader.h"
#include "mirror/object-inl.h"
#include "mirror/object_array-inl.h"
#include "oat_writer.h"
#include "os.h"
#include "runtime.h"
#include "runtime_options.h"
#include "ScopedLocalRef.h"
#include "scoped_thread_state_change.h"
#include "utils.h"
#include "well_known_classes.h"
#include "zip_archive.h"

namespace art {

static int original_argc;
static char** original_argv;

static std::string CommandLine() {
  std::vector<std::string> command;
  for (int i = 0; i < original_argc; ++i) {
    command.push_back(original_argv[i]);
  }
  return Join(command, ' ');
}

// A stripped version. Remove some less essential parameters. If we see a "--zip-fd=" parameter, be
// even more aggressive. There won't be much reasonable data here for us in that case anyways (the
// locations are all staged).
static std::string StrippedCommandLine() {
  std::vector<std::string> command;

  // Do a pre-pass to look for zip-fd.
  bool saw_zip_fd = false;
  for (int i = 0; i < original_argc; ++i) {
    if (StartsWith(original_argv[i], "--zip-fd=")) {
      saw_zip_fd = true;
      break;
    }
  }

  // Now filter out things.
  for (int i = 0; i < original_argc; ++i) {
    // All runtime-arg parameters are dropped.
    if (strcmp(original_argv[i], "--runtime-arg") == 0) {
      i++;  // Drop the next part, too.
      continue;
    }

    // Any instruction-setXXX is dropped.
    if (StartsWith(original_argv[i], "--instruction-set")) {
      continue;
    }

    // The boot image is dropped.
    if (StartsWith(original_argv[i], "--boot-image=")) {
      continue;
    }

    // This should leave any dex-file and oat-file options, describing what we compiled.

    // However, we prefer to drop this when we saw --zip-fd.
    if (saw_zip_fd) {
      // Drop anything --zip-X, --dex-X, --oat-X, --swap-X, or --app-image-X
      if (StartsWith(original_argv[i], "--zip-") ||
          StartsWith(original_argv[i], "--dex-") ||
          StartsWith(original_argv[i], "--oat-") ||
          StartsWith(original_argv[i], "--swap-") ||
          StartsWith(original_argv[i], "--app-image-")) {
        continue;
      }
    }

    command.push_back(original_argv[i]);
  }

  // Construct the final output.
  if (command.size() <= 1U) {
    // It seems only "/system/bin/dex2oat" is left, or not even that. Use a pretty line.
    return "Starting dex2oat.";
  }
  return Join(command, ' ');
}

static void UsageErrorV(const char* fmt, va_list ap) {
  std::string error;
  StringAppendV(&error, fmt, ap);
  LOG(ERROR) << error;
}

static void UsageError(const char* fmt, ...) {
  va_list ap;
  va_start(ap, fmt);
  UsageErrorV(fmt, ap);
  va_end(ap);
}

NO_RETURN static void Usage(const char* fmt, ...) {
  va_list ap;
  va_start(ap, fmt);
  UsageErrorV(fmt, ap);
  va_end(ap);

  UsageError("Command: %s", CommandLine().c_str());

  UsageError("Usage: dex2oat [options]...");
  UsageError("");
  UsageError("  -j<number>: specifies the number of threads used for compilation.");
  UsageError("       Default is the number of detected hardware threads available on the");
  UsageError("       host system.");
  UsageError("      Example: -j12");
  UsageError("");
  UsageError("  --dex-file=<dex-file>: specifies a .dex, .jar, or .apk file to compile.");
  UsageError("      Example: --dex-file=/system/framework/core.jar");
  UsageError("");
  UsageError("  --dex-location=<dex-location>: specifies an alternative dex location to");
  UsageError("      encode in the oat file for the corresponding --dex-file argument.");
  UsageError("      Example: --dex-file=/home/build/out/system/framework/core.jar");
  UsageError("               --dex-location=/system/framework/core.jar");
  UsageError("");
  UsageError("  --zip-fd=<file-descriptor>: specifies a file descriptor of a zip file");
  UsageError("      containing a classes.dex file to compile.");
  UsageError("      Example: --zip-fd=5");
  UsageError("");
  UsageError("  --zip-location=<zip-location>: specifies a symbolic name for the file");
  UsageError("      corresponding to the file descriptor specified by --zip-fd.");
  UsageError("      Example: --zip-location=/system/app/Calculator.apk");
  UsageError("");
  UsageError("  --oat-file=<file.oat>: specifies an oat output destination via a filename.");
  UsageError("      Example: --oat-file=/system/framework/boot.oat");
  UsageError("");
  UsageError("  --oat-fd=<number>: specifies the oat output destination via a file descriptor.");
  UsageError("      Example: --oat-fd=6");
  UsageError("");
  UsageError("  --oat-location=<oat-name>: specifies a symbolic name for the file corresponding");
  UsageError("      to the file descriptor specified by --oat-fd.");
  UsageError("      Example: --oat-location=/data/dalvik-cache/system@app@Calculator.apk.oat");
  UsageError("");
  UsageError("  --oat-symbols=<file.oat>: specifies an oat output destination with full symbols.");
  UsageError("      Example: --oat-symbols=/symbols/system/framework/boot.oat");
  UsageError("");
  UsageError("  --image=<file.art>: specifies an output image filename.");
  UsageError("      Example: --image=/system/framework/boot.art");
  UsageError("");
  UsageError("  --image-format=(uncompressed|lz4):");
  UsageError("      Which format to store the image.");
  UsageError("      Example: --image-format=lz4");
  UsageError("      Default: uncompressed");
  UsageError("");
  UsageError("  --image-classes=<classname-file>: specifies classes to include in an image.");
  UsageError("      Example: --image=frameworks/base/preloaded-classes");
  UsageError("");
  UsageError("  --base=<hex-address>: specifies the base address when creating a boot image.");
  UsageError("      Example: --base=0x50000000");
  UsageError("");
  UsageError("  --boot-image=<file.art>: provide the image file for the boot class path.");
  UsageError("      Do not include the arch as part of the name, it is added automatically.");
  UsageError("      Example: --boot-image=/system/framework/boot.art");
  UsageError("               (specifies /system/framework/<arch>/boot.art as the image file)");
  UsageError("      Default: $ANDROID_ROOT/system/framework/boot.art");
  UsageError("");
  UsageError("  --android-root=<path>: used to locate libraries for portable linking.");
  UsageError("      Example: --android-root=out/host/linux-x86");
  UsageError("      Default: $ANDROID_ROOT");
  UsageError("");
  UsageError("  --instruction-set=(arm|arm64|mips|mips64|x86|x86_64): compile for a particular");
  UsageError("      instruction set.");
  UsageError("      Example: --instruction-set=x86");
  UsageError("      Default: arm");
  UsageError("");
  UsageError("  --instruction-set-features=...,: Specify instruction set features");
  UsageError("      Example: --instruction-set-features=div");
  UsageError("      Default: default");
  UsageError("");
  UsageError("  --compile-pic: Force indirect use of code, methods, and classes");
  UsageError("      Default: disabled");
  UsageError("");
  UsageError("  --compiler-backend=(Quick|Optimizing): select compiler backend");
  UsageError("      set.");
  UsageError("      Example: --compiler-backend=Optimizing");
  UsageError("      Default: Optimizing");
  UsageError("");
  UsageError("  --compiler-filter="
                "(verify-none"
                "|interpret-only"
                "|space"
                "|balanced"
                "|speed"
                "|everything"
                "|time):");
  UsageError("      select compiler filter.");
  UsageError("      Example: --compiler-filter=everything");
  UsageError("      Default: speed");
  UsageError("");
  UsageError("  --huge-method-max=<method-instruction-count>: threshold size for a huge");
  UsageError("      method for compiler filter tuning.");
  UsageError("      Example: --huge-method-max=%d", CompilerOptions::kDefaultHugeMethodThreshold);
  UsageError("      Default: %d", CompilerOptions::kDefaultHugeMethodThreshold);
  UsageError("");
  UsageError("  --large-method-max=<method-instruction-count>: threshold size for a large");
  UsageError("      method for compiler filter tuning.");
  UsageError("      Example: --large-method-max=%d", CompilerOptions::kDefaultLargeMethodThreshold);
  UsageError("      Default: %d", CompilerOptions::kDefaultLargeMethodThreshold);
  UsageError("");
  UsageError("  --small-method-max=<method-instruction-count>: threshold size for a small");
  UsageError("      method for compiler filter tuning.");
  UsageError("      Example: --small-method-max=%d", CompilerOptions::kDefaultSmallMethodThreshold);
  UsageError("      Default: %d", CompilerOptions::kDefaultSmallMethodThreshold);
  UsageError("");
  UsageError("  --tiny-method-max=<method-instruction-count>: threshold size for a tiny");
  UsageError("      method for compiler filter tuning.");
  UsageError("      Example: --tiny-method-max=%d", CompilerOptions::kDefaultTinyMethodThreshold);
  UsageError("      Default: %d", CompilerOptions::kDefaultTinyMethodThreshold);
  UsageError("");
  UsageError("  --num-dex-methods=<method-count>: threshold size for a small dex file for");
  UsageError("      compiler filter tuning. If the input has fewer than this many methods");
  UsageError("      and the filter is not interpret-only or verify-none, overrides the");
  UsageError("      filter to use speed");
  UsageError("      Example: --num-dex-method=%d", CompilerOptions::kDefaultNumDexMethodsThreshold);
  UsageError("      Default: %d", CompilerOptions::kDefaultNumDexMethodsThreshold);
  UsageError("");
  UsageError("  --inline-depth-limit=<depth-limit>: the depth limit of inlining for fine tuning");
  UsageError("      the compiler. A zero value will disable inlining. Honored only by Optimizing.");
  UsageError("      Has priority over the --compiler-filter option. Intended for ");
  UsageError("      development/experimental use.");
  UsageError("      Example: --inline-depth-limit=%d", CompilerOptions::kDefaultInlineDepthLimit);
  UsageError("      Default: %d", CompilerOptions::kDefaultInlineDepthLimit);
  UsageError("");
  UsageError("  --inline-max-code-units=<code-units-count>: the maximum code units that a method");
  UsageError("      can have to be considered for inlining. A zero value will disable inlining.");
  UsageError("      Honored only by Optimizing. Has priority over the --compiler-filter option.");
  UsageError("      Intended for development/experimental use.");
  UsageError("      Example: --inline-max-code-units=%d",
             CompilerOptions::kDefaultInlineMaxCodeUnits);
  UsageError("      Default: %d", CompilerOptions::kDefaultInlineMaxCodeUnits);
  UsageError("");
  UsageError("  --dump-timing: display a breakdown of where time was spent");
  UsageError("");
  UsageError("  --include-patch-information: Include patching information so the generated code");
  UsageError("      can have its base address moved without full recompilation.");
  UsageError("");
  UsageError("  --no-include-patch-information: Do not include patching information.");
  UsageError("");
  UsageError("  -g");
  UsageError("  --generate-debug-info: Generate debug information for native debugging,");
  UsageError("      such as stack unwinding information, ELF symbols and DWARF sections.");
  UsageError("      This generates all the available information. Unneeded parts can be");
  UsageError("      stripped using standard command line tools such as strip or objcopy.");
  UsageError("      (enabled by default in debug builds, disabled by default otherwise)");
  UsageError("");
  UsageError("  --no-generate-debug-info: Do not generate debug information for native debugging.");
  UsageError("");
  UsageError("  --debuggable: Produce code debuggable with Java debugger. Implies -g.");
  UsageError("");
  UsageError("  --native-debuggable: Produce code debuggable with native debugger (like LLDB).");
  UsageError("      Implies --debuggable.");
  UsageError("");
  UsageError("  --runtime-arg <argument>: used to specify various arguments for the runtime,");
  UsageError("      such as initial heap size, maximum heap size, and verbose output.");
  UsageError("      Use a separate --runtime-arg switch for each argument.");
  UsageError("      Example: --runtime-arg -Xms256m");
  UsageError("");
  UsageError("  --profile-file=<filename>: specify profiler output file to use for compilation.");
  UsageError("");
  UsageError("  --print-pass-names: print a list of pass names");
  UsageError("");
  UsageError("  --disable-passes=<pass-names>:  disable one or more passes separated by comma.");
  UsageError("      Example: --disable-passes=UseCount,BBOptimizations");
  UsageError("");
  UsageError("  --print-pass-options: print a list of passes that have configurable options along "
             "with the setting.");
  UsageError("      Will print default if no overridden setting exists.");
  UsageError("");
  UsageError("  --pass-options=Pass1Name:Pass1OptionName:Pass1Option#,"
             "Pass2Name:Pass2OptionName:Pass2Option#");
  UsageError("      Used to specify a pass specific option. The setting itself must be integer.");
  UsageError("      Separator used between options is a comma.");
  UsageError("");
  UsageError("  --swap-file=<file-name>:  specifies a file to use for swap.");
  UsageError("      Example: --swap-file=/data/tmp/swap.001");
  UsageError("");
  UsageError("  --swap-fd=<file-descriptor>:  specifies a file to use for swap (by descriptor).");
  UsageError("      Example: --swap-fd=10");
  UsageError("");
  UsageError("  --app-image-fd=<file-descriptor>: specify output file descriptor for app image.");
  UsageError("      Example: --app-image-fd=10");
  UsageError("");
  UsageError("  --app-image-file=<file-name>: specify a file name for app image.");
  UsageError("      Example: --app-image-file=/data/dalvik-cache/system@app@Calculator.apk.art");
  UsageError("");
  UsageError("  --multi-image: specify that separate oat and image files be generated for each "
             "input dex file.");
  UsageError("");
  std::cerr << "See log for usage error information\n";
  exit(EXIT_FAILURE);
}

// The primary goal of the watchdog is to prevent stuck build servers
// during development when fatal aborts lead to a cascade of failures
// that result in a deadlock.
class WatchDog {
// WatchDog defines its own CHECK_PTHREAD_CALL to avoid using LOG which uses locks
#undef CHECK_PTHREAD_CALL
#define CHECK_WATCH_DOG_PTHREAD_CALL(call, args, what) \
  do { \
    int rc = call args; \
    if (rc != 0) { \
      errno = rc; \
      std::string message(# call); \
      message += " failed for "; \
      message += reason; \
      Fatal(message); \
    } \
  } while (false)

 public:
  explicit WatchDog(bool is_watch_dog_enabled) {
    is_watch_dog_enabled_ = is_watch_dog_enabled;
    if (!is_watch_dog_enabled_) {
      return;
    }
    shutting_down_ = false;
    const char* reason = "dex2oat watch dog thread startup";
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_mutex_init, (&mutex_, nullptr), reason);
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_cond_init, (&cond_, nullptr), reason);
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_attr_init, (&attr_), reason);
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_create, (&pthread_, &attr_, &CallBack, this), reason);
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_attr_destroy, (&attr_), reason);
  }
  ~WatchDog() {
    if (!is_watch_dog_enabled_) {
      return;
    }
    const char* reason = "dex2oat watch dog thread shutdown";
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_mutex_lock, (&mutex_), reason);
    shutting_down_ = true;
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_cond_signal, (&cond_), reason);
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_mutex_unlock, (&mutex_), reason);

    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_join, (pthread_, nullptr), reason);

    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_cond_destroy, (&cond_), reason);
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_mutex_destroy, (&mutex_), reason);
  }

 private:
  static void* CallBack(void* arg) {
    WatchDog* self = reinterpret_cast<WatchDog*>(arg);
    ::art::SetThreadName("dex2oat watch dog");
    self->Wait();
    return nullptr;
  }

  NO_RETURN static void Fatal(const std::string& message) {
    // TODO: When we can guarantee it won't prevent shutdown in error cases, move to LOG. However,
    //       it's rather easy to hang in unwinding.
    //       LogLine also avoids ART logging lock issues, as it's really only a wrapper around
    //       logcat logging or stderr output.
    LogMessage::LogLine(__FILE__, __LINE__, LogSeverity::FATAL, message.c_str());
    exit(1);
  }

  void Wait() {
    // TODO: tune the multiplier for GC verification, the following is just to make the timeout
    //       large.
    constexpr int64_t multiplier = kVerifyObjectSupport > kVerifyObjectModeFast ? 100 : 1;
    timespec timeout_ts;
    InitTimeSpec(true, CLOCK_REALTIME, multiplier * kWatchDogTimeoutSeconds * 1000, 0, &timeout_ts);
    const char* reason = "dex2oat watch dog thread waiting";
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_mutex_lock, (&mutex_), reason);
    while (!shutting_down_) {
      int rc = TEMP_FAILURE_RETRY(pthread_cond_timedwait(&cond_, &mutex_, &timeout_ts));
      if (rc == ETIMEDOUT) {
        Fatal(StringPrintf("dex2oat did not finish after %" PRId64 " seconds",
                           kWatchDogTimeoutSeconds));
      } else if (rc != 0) {
        std::string message(StringPrintf("pthread_cond_timedwait failed: %s",
                                         strerror(errno)));
        Fatal(message.c_str());
      }
    }
    CHECK_WATCH_DOG_PTHREAD_CALL(pthread_mutex_unlock, (&mutex_), reason);
  }

  // When setting timeouts, keep in mind that the build server may not be as fast as your desktop.
  // Debug builds are slower so they have larger timeouts.
  static constexpr int64_t kSlowdownFactor = kIsDebugBuild ? 5U : 1U;

  // 9.5 minutes scaled by kSlowdownFactor. This is slightly smaller than the Package Manager
  // watchdog (PackageManagerService.WATCHDOG_TIMEOUT, 10 minutes), so that dex2oat will abort
  // itself before that watchdog would take down the system server.
  static constexpr int64_t kWatchDogTimeoutSeconds = kSlowdownFactor * (9 * 60 + 30);

  bool is_watch_dog_enabled_;
  bool shutting_down_;
  // TODO: Switch to Mutex when we can guarantee it won't prevent shutdown in error cases.
  pthread_mutex_t mutex_;
  pthread_cond_t cond_;
  pthread_attr_t attr_;
  pthread_t pthread_;
};

static constexpr size_t kMinDexFilesForSwap = 2;
static constexpr size_t kMinDexFileCumulativeSizeForSwap = 20 * MB;

static bool UseSwap(bool is_image, std::vector<const DexFile*>& dex_files) {
  if (is_image) {
    // Don't use swap, we know generation should succeed, and we don't want to slow it down.
    return false;
  }
  if (dex_files.size() < kMinDexFilesForSwap) {
    // If there are less dex files than the threshold, assume it's gonna be fine.
    return false;
  }
  size_t dex_files_size = 0;
  for (const auto* dex_file : dex_files) {
    dex_files_size += dex_file->GetHeader().file_size_;
  }
  return dex_files_size >= kMinDexFileCumulativeSizeForSwap;
}

class Dex2Oat FINAL {
 public:
  explicit Dex2Oat(TimingLogger* timings) :
      compiler_kind_(Compiler::kOptimizing),
      instruction_set_(kRuntimeISA),
      // Take the default set of instruction features from the build.
      verification_results_(nullptr),
      method_inliner_map_(),
      runtime_(nullptr),
      thread_count_(sysconf(_SC_NPROCESSORS_CONF)),
      start_ns_(NanoTime()),
      oat_fd_(-1),
      zip_fd_(-1),
      image_base_(0U),
      image_classes_zip_filename_(nullptr),
      image_classes_filename_(nullptr),
      image_storage_mode_(ImageHeader::kStorageModeUncompressed),
      compiled_classes_zip_filename_(nullptr),
      compiled_classes_filename_(nullptr),
      compiled_methods_zip_filename_(nullptr),
      compiled_methods_filename_(nullptr),
      app_image_(false),
      boot_image_(false),
      is_host_(false),
      image_writer_(nullptr),
      driver_(nullptr),
      dump_stats_(false),
      dump_passes_(false),
      dump_timing_(false),
      dump_slow_timing_(kIsDebugBuild),
      dump_cfg_append_(false),
      swap_fd_(-1),
      app_image_fd_(kInvalidImageFd),
      timings_(timings) {}

  ~Dex2Oat() {
    // Free opened dex files before deleting the runtime_, because ~DexFile
    // uses MemMap, which is shut down by ~Runtime.
    class_path_files_.clear();
    opened_dex_files_.clear();

    // Log completion time before deleting the runtime_, because this accesses
    // the runtime.
    LogCompletionTime();

    if (!kIsDebugBuild && !(RUNNING_ON_MEMORY_TOOL && kMemoryToolDetectsLeaks)) {
      // We want to just exit on non-debug builds, not bringing the runtime down
      // in an orderly fashion. So release the following fields.
      driver_.release();
      image_writer_.release();
      for (std::unique_ptr<const DexFile>& dex_file : opened_dex_files_) {
        dex_file.release();
      }
      for (std::unique_ptr<File>& oat_file : oat_files_) {
        oat_file.release();
      }
      runtime_.release();
      verification_results_.release();
      key_value_store_.release();
    }
  }

  struct ParserOptions {
    std::vector<const char*> oat_symbols;
    std::string boot_image_filename;
    bool watch_dog_enabled = true;
    bool requested_specific_compiler = false;
    std::string error_msg;
  };

  void ParseZipFd(const StringPiece& option) {
    ParseUintOption(option, "--zip-fd", &zip_fd_, Usage);
  }

  void ParseOatFd(const StringPiece& option) {
    ParseUintOption(option, "--oat-fd", &oat_fd_, Usage);
  }

  void ParseJ(const StringPiece& option) {
    ParseUintOption(option, "-j", &thread_count_, Usage, /* is_long_option */ false);
  }

  void ParseBase(const StringPiece& option) {
    DCHECK(option.starts_with("--base="));
    const char* image_base_str = option.substr(strlen("--base=")).data();
    char* end;
    image_base_ = strtoul(image_base_str, &end, 16);
    if (end == image_base_str || *end != '\0') {
      Usage("Failed to parse hexadecimal value for option %s", option.data());
    }
  }

  void ParseInstructionSet(const StringPiece& option) {
    DCHECK(option.starts_with("--instruction-set="));
    StringPiece instruction_set_str = option.substr(strlen("--instruction-set=")).data();
    // StringPiece is not necessarily zero-terminated, so need to make a copy and ensure it.
    std::unique_ptr<char[]> buf(new char[instruction_set_str.length() + 1]);
    strncpy(buf.get(), instruction_set_str.data(), instruction_set_str.length());
    buf.get()[instruction_set_str.length()] = 0;
    instruction_set_ = GetInstructionSetFromString(buf.get());
    // arm actually means thumb2.
    if (instruction_set_ == InstructionSet::kArm) {
      instruction_set_ = InstructionSet::kThumb2;
    }
  }

  void ParseInstructionSetVariant(const StringPiece& option, ParserOptions* parser_options) {
    DCHECK(option.starts_with("--instruction-set-variant="));
    StringPiece str = option.substr(strlen("--instruction-set-variant=")).data();
    instruction_set_features_.reset(
        InstructionSetFeatures::FromVariant(
            instruction_set_, str.as_string(), &parser_options->error_msg));
    if (instruction_set_features_.get() == nullptr) {
      Usage("%s", parser_options->error_msg.c_str());
    }
  }

  void ParseInstructionSetFeatures(const StringPiece& option, ParserOptions* parser_options) {
    DCHECK(option.starts_with("--instruction-set-features="));
    StringPiece str = option.substr(strlen("--instruction-set-features=")).data();
    if (instruction_set_features_.get() == nullptr) {
      instruction_set_features_.reset(
          InstructionSetFeatures::FromVariant(
              instruction_set_, "default", &parser_options->error_msg));
      if (instruction_set_features_.get() == nullptr) {
        Usage("Problem initializing default instruction set features variant: %s",
              parser_options->error_msg.c_str());
      }
    }
    instruction_set_features_.reset(
        instruction_set_features_->AddFeaturesFromString(str.as_string(),
                                                         &parser_options->error_msg));
    if (instruction_set_features_.get() == nullptr) {
      Usage("Error parsing '%s': %s", option.data(), parser_options->error_msg.c_str());
    }
  }

  void ParseCompilerBackend(const StringPiece& option, ParserOptions* parser_options) {
    DCHECK(option.starts_with("--compiler-backend="));
    parser_options->requested_specific_compiler = true;
    StringPiece backend_str = option.substr(strlen("--compiler-backend=")).data();
    if (backend_str == "Quick") {
      compiler_kind_ = Compiler::kQuick;
    } else if (backend_str == "Optimizing") {
      compiler_kind_ = Compiler::kOptimizing;
    } else {
      Usage("Unknown compiler backend: %s", backend_str.data());
    }
  }

  void ParseImageFormat(const StringPiece& option) {
    const StringPiece substr("--image-format=");
    DCHECK(option.starts_with(substr));
    const StringPiece format_str = option.substr(substr.length());
    if (format_str == "lz4") {
      image_storage_mode_ = ImageHeader::kStorageModeLZ4;
    } else if (format_str == "uncompressed") {
      image_storage_mode_ = ImageHeader::kStorageModeUncompressed;
    } else {
      Usage("Unknown image format: %s", format_str.data());
    }
  }

  void ProcessOptions(ParserOptions* parser_options, bool multi_image) {
    boot_image_ = !image_filenames_.empty();
    app_image_ = app_image_fd_ != -1 || !app_image_file_name_.empty();

    if (IsAppImage() && IsBootImage()) {
      Usage("Can't have both --image and (--app-image-fd or --app-image-file)");
    }

    if (IsBootImage()) {
      // We need the boot image to always be debuggable.
      compiler_options_->debuggable_ = true;
    }

    if (oat_filenames_.empty() && oat_fd_ == -1) {
      Usage("Output must be supplied with either --oat-file or --oat-fd");
    }

    if (!oat_filenames_.empty() && oat_fd_ != -1) {
      Usage("--oat-file should not be used with --oat-fd");
    }

    if (!parser_options->oat_symbols.empty() && oat_fd_ != -1) {
      Usage("--oat-symbols should not be used with --oat-fd");
    }

    if (!parser_options->oat_symbols.empty() && is_host_) {
      Usage("--oat-symbols should not be used with --host");
    }

    if (oat_fd_ != -1 && !image_filenames_.empty()) {
      Usage("--oat-fd should not be used with --image");
    }

    if (!parser_options->oat_symbols.empty() &&
        parser_options->oat_symbols.size() != oat_filenames_.size()) {
      Usage("--oat-file arguments do not match --oat-symbols arguments");
    }

    if (!image_filenames_.empty() && image_filenames_.size() != oat_filenames_.size()) {
      Usage("--oat-file arguments do not match --image arguments");
    }

    if (android_root_.empty()) {
      const char* android_root_env_var = getenv("ANDROID_ROOT");
      if (android_root_env_var == nullptr) {
        Usage("--android-root unspecified and ANDROID_ROOT not set");
      }
      android_root_ += android_root_env_var;
    }

    if (!boot_image_ && parser_options->boot_image_filename.empty()) {
      parser_options->boot_image_filename += android_root_;
      parser_options->boot_image_filename += "/framework/boot.art";
    }
    if (!parser_options->boot_image_filename.empty()) {
      boot_image_filename_ = parser_options->boot_image_filename;
    }

    if (image_classes_filename_ != nullptr && !IsBootImage()) {
      Usage("--image-classes should only be used with --image");
    }

    if (image_classes_filename_ != nullptr && !boot_image_filename_.empty()) {
      Usage("--image-classes should not be used with --boot-image");
    }

    if (image_classes_zip_filename_ != nullptr && image_classes_filename_ == nullptr) {
      Usage("--image-classes-zip should be used with --image-classes");
    }

    if (compiled_classes_filename_ != nullptr && !IsBootImage()) {
      Usage("--compiled-classes should only be used with --image");
    }

    if (compiled_classes_filename_ != nullptr && !boot_image_filename_.empty()) {
      Usage("--compiled-classes should not be used with --boot-image");
    }

    if (compiled_classes_zip_filename_ != nullptr && compiled_classes_filename_ == nullptr) {
      Usage("--compiled-classes-zip should be used with --compiled-classes");
    }

    if (dex_filenames_.empty() && zip_fd_ == -1) {
      Usage("Input must be supplied with either --dex-file or --zip-fd");
    }

    if (!dex_filenames_.empty() && zip_fd_ != -1) {
      Usage("--dex-file should not be used with --zip-fd");
    }

    if (!dex_filenames_.empty() && !zip_location_.empty()) {
      Usage("--dex-file should not be used with --zip-location");
    }

    if (dex_locations_.empty()) {
      for (const char* dex_file_name : dex_filenames_) {
        dex_locations_.push_back(dex_file_name);
      }
    } else if (dex_locations_.size() != dex_filenames_.size()) {
      Usage("--dex-location arguments do not match --dex-file arguments");
    }

    if (!dex_filenames_.empty() && !oat_filenames_.empty()) {
      if (oat_filenames_.size() != 1 && oat_filenames_.size() != dex_filenames_.size()) {
        Usage("--oat-file arguments must be singular or match --dex-file arguments");
      }
    }

    if (zip_fd_ != -1 && zip_location_.empty()) {
      Usage("--zip-location should be supplied with --zip-fd");
    }

    if (boot_image_filename_.empty()) {
      if (image_base_ == 0) {
        Usage("Non-zero --base not specified");
      }
    }

    if (!parser_options->oat_symbols.empty()) {
      oat_unstripped_ = std::move(parser_options->oat_symbols);
    }

    // If no instruction set feature was given, use the default one for the target
    // instruction set.
    if (instruction_set_features_.get() == nullptr) {
      instruction_set_features_.reset(
          InstructionSetFeatures::FromVariant(
              instruction_set_, "default", &parser_options->error_msg));
      if (instruction_set_features_.get() == nullptr) {
        Usage("Problem initializing default instruction set features variant: %s",
              parser_options->error_msg.c_str());
      }
    }

    if (instruction_set_ == kRuntimeISA) {
      std::unique_ptr<const InstructionSetFeatures> runtime_features(
          InstructionSetFeatures::FromCppDefines());
      if (!instruction_set_features_->Equals(runtime_features.get())) {
        LOG(WARNING) << "Mismatch between dex2oat instruction set features ("
            << *instruction_set_features_ << ") and those of dex2oat executable ("
            << *runtime_features <<") for the command line:\n"
            << CommandLine();
      }
    }

    // It they are not set, use default values for inlining settings.
    // TODO: We should rethink the compiler filter. We mostly save
    // time here, which is orthogonal to space.
    if (compiler_options_->inline_depth_limit_ == CompilerOptions::kUnsetInlineDepthLimit) {
      compiler_options_->inline_depth_limit_ =
          (compiler_options_->compiler_filter_ == CompilerOptions::kSpace)
          // Implementation of the space filter: limit inlining depth.
          ? CompilerOptions::kSpaceFilterInlineDepthLimit
          : CompilerOptions::kDefaultInlineDepthLimit;
    }
    if (compiler_options_->inline_max_code_units_ == CompilerOptions::kUnsetInlineMaxCodeUnits) {
      compiler_options_->inline_max_code_units_ =
          (compiler_options_->compiler_filter_ == CompilerOptions::kSpace)
          // Implementation of the space filter: limit inlining max code units.
          ? CompilerOptions::kSpaceFilterInlineMaxCodeUnits
          : CompilerOptions::kDefaultInlineMaxCodeUnits;
    }

    // Checks are all explicit until we know the architecture.
    // Set the compilation target's implicit checks options.
    switch (instruction_set_) {
      case kArm:
      case kThumb2:
      case kArm64:
      case kX86:
      case kX86_64:
      case kMips:
      case kMips64:
        compiler_options_->implicit_null_checks_ = true;
        compiler_options_->implicit_so_checks_ = true;
        break;

      default:
        // Defaults are correct.
        break;
    }

    compiler_options_->verbose_methods_ = verbose_methods_.empty() ? nullptr : &verbose_methods_;

    if (!IsBootImage() && multi_image) {
      Usage("--multi-image can only be used when creating boot images");
    }
    if (IsBootImage() && multi_image && image_filenames_.size() > 1) {
      Usage("--multi-image cannot be used with multiple image names");
    }

    // For now, if we're on the host and compile the boot image, *always* use multiple image files.
    if (!kIsTargetBuild && IsBootImage()) {
      if (image_filenames_.size() == 1) {
        multi_image = true;
      }
    }

    if (IsBootImage() && multi_image) {
      // Expand the oat and image filenames.
      std::string base_oat = oat_filenames_[0];
      size_t last_oat_slash = base_oat.rfind('/');
      if (last_oat_slash == std::string::npos) {
        Usage("--multi-image used with unusable oat filename %s", base_oat.c_str());
      }
      base_oat = base_oat.substr(0, last_oat_slash + 1);

      std::string base_img = image_filenames_[0];
      size_t last_img_slash = base_img.rfind('/');
      if (last_img_slash == std::string::npos) {
        Usage("--multi-image used with unusable image filename %s", base_img.c_str());
      }
      base_img = base_img.substr(0, last_img_slash + 1);

      // Now create the other names.
      // Note: we have some special case here for our testing. We have to inject the differentiating
      //       parts for the different core images.
      std::string infix;  // Empty infix by default.
      {
        // Check the first name.
        std::string dex_file = oat_filenames_[0];
        size_t last_dex_slash = dex_file.rfind('/');
        if (last_dex_slash != std::string::npos) {
          dex_file = dex_file.substr(last_dex_slash + 1);
        }
        size_t last_dex_dot = dex_file.rfind('.');
        if (last_dex_dot != std::string::npos) {
          dex_file = dex_file.substr(0, last_dex_dot);
        }
        if (StartsWith(dex_file, "core-")) {
          infix = dex_file.substr(strlen("core"));
        }
      }
      // Use a counted loop to skip the first one.
      for (size_t i = 1; i < dex_locations_.size(); ++i) {
        // TODO: Make everything properly std::string.
        std::string image_name = CreateMultiImageName(dex_locations_[i], infix, ".art");
        char_backing_storage_.push_back(base_img + image_name);
        image_filenames_.push_back((char_backing_storage_.end() - 1)->c_str());

        std::string oat_name = CreateMultiImageName(dex_locations_[i], infix, ".oat");
        char_backing_storage_.push_back(base_oat + oat_name);
        oat_filenames_.push_back((char_backing_storage_.end() - 1)->c_str());
      }
    }

    // Done with usage checks, enable watchdog if requested
    if (parser_options->watch_dog_enabled) {
      watchdog_.reset(new WatchDog(true));
    }

    // Fill some values into the key-value store for the oat header.
    key_value_store_.reset(new SafeMap<std::string, std::string>());
  }

  static std::string CreateMultiImageName(std::string in,
                                          const std::string& infix,
                                          const char* suffix) {
    size_t last_dex_slash = in.rfind('/');
    if (last_dex_slash != std::string::npos) {
      in = in.substr(last_dex_slash + 1);
    }
    if (!infix.empty()) {
      // Inject infix.
      size_t last_dot = in.rfind('.');
      if (last_dot != std::string::npos) {
        in.insert(last_dot, infix);
      }
    }
    if (EndsWith(in, ".jar")) {
      in = in.substr(0, in.length() - strlen(".jar")) + (suffix != nullptr ? suffix : "");
    }
    return in;
  }

  void InsertCompileOptions(int argc, char** argv) {
    std::ostringstream oss;
    for (int i = 0; i < argc; ++i) {
      if (i > 0) {
        oss << ' ';
      }
      oss << argv[i];
    }
    key_value_store_->Put(OatHeader::kDex2OatCmdLineKey, oss.str());
    oss.str("");  // Reset.
    oss << kRuntimeISA;
    key_value_store_->Put(OatHeader::kDex2OatHostKey, oss.str());
    key_value_store_->Put(
        OatHeader::kPicKey,
        compiler_options_->compile_pic_ ? OatHeader::kTrueValue : OatHeader::kFalseValue);
    key_value_store_->Put(
        OatHeader::kDebuggableKey,
        compiler_options_->debuggable_ ? OatHeader::kTrueValue : OatHeader::kFalseValue);
  }

  // Parse the arguments from the command line. In case of an unrecognized option or impossible
  // values/combinations, a usage error will be displayed and exit() is called. Thus, if the method
  // returns, arguments have been successfully parsed.
  void ParseArgs(int argc, char** argv) {
    original_argc = argc;
    original_argv = argv;

    InitLogging(argv);

    // Skip over argv[0].
    argv++;
    argc--;

    if (argc == 0) {
      Usage("No arguments specified");
    }

    std::unique_ptr<ParserOptions> parser_options(new ParserOptions());
    compiler_options_.reset(new CompilerOptions());

    bool multi_image = false;

    for (int i = 0; i < argc; i++) {
      const StringPiece option(argv[i]);
      const bool log_options = false;
      if (log_options) {
        LOG(INFO) << "dex2oat: option[" << i << "]=" << argv[i];
      }
      if (option.starts_with("--dex-file=")) {
        dex_filenames_.push_back(option.substr(strlen("--dex-file=")).data());
      } else if (option.starts_with("--dex-location=")) {
        dex_locations_.push_back(option.substr(strlen("--dex-location=")).data());
      } else if (option.starts_with("--zip-fd=")) {
        ParseZipFd(option);
      } else if (option.starts_with("--zip-location=")) {
        zip_location_ = option.substr(strlen("--zip-location=")).data();
      } else if (option.starts_with("--oat-file=")) {
        oat_filenames_.push_back(option.substr(strlen("--oat-file=")).data());
      } else if (option.starts_with("--oat-symbols=")) {
        parser_options->oat_symbols.push_back(option.substr(strlen("--oat-symbols=")).data());
      } else if (option.starts_with("--oat-fd=")) {
        ParseOatFd(option);
      } else if (option == "--watch-dog") {
        parser_options->watch_dog_enabled = true;
      } else if (option == "--no-watch-dog") {
        parser_options->watch_dog_enabled = false;
      } else if (option.starts_with("-j")) {
        ParseJ(option);
      } else if (option.starts_with("--oat-location=")) {
        oat_location_ = option.substr(strlen("--oat-location=")).data();
      } else if (option.starts_with("--image=")) {
        image_filenames_.push_back(option.substr(strlen("--image=")).data());
      } else if (option.starts_with("--image-classes=")) {
        image_classes_filename_ = option.substr(strlen("--image-classes=")).data();
      } else if (option.starts_with("--image-classes-zip=")) {
        image_classes_zip_filename_ = option.substr(strlen("--image-classes-zip=")).data();
      } else if (option.starts_with("--image-format=")) {
        ParseImageFormat(option);
      } else if (option.starts_with("--compiled-classes=")) {
        compiled_classes_filename_ = option.substr(strlen("--compiled-classes=")).data();
      } else if (option.starts_with("--compiled-classes-zip=")) {
        compiled_classes_zip_filename_ = option.substr(strlen("--compiled-classes-zip=")).data();
      } else if (option.starts_with("--compiled-methods=")) {
        compiled_methods_filename_ = option.substr(strlen("--compiled-methods=")).data();
      } else if (option.starts_with("--compiled-methods-zip=")) {
        compiled_methods_zip_filename_ = option.substr(strlen("--compiled-methods-zip=")).data();
      } else if (option.starts_with("--base=")) {
        ParseBase(option);
      } else if (option.starts_with("--boot-image=")) {
        parser_options->boot_image_filename = option.substr(strlen("--boot-image=")).data();
      } else if (option.starts_with("--android-root=")) {
        android_root_ = option.substr(strlen("--android-root=")).data();
      } else if (option.starts_with("--instruction-set=")) {
        ParseInstructionSet(option);
      } else if (option.starts_with("--instruction-set-variant=")) {
        ParseInstructionSetVariant(option, parser_options.get());
      } else if (option.starts_with("--instruction-set-features=")) {
        ParseInstructionSetFeatures(option, parser_options.get());
      } else if (option.starts_with("--compiler-backend=")) {
        ParseCompilerBackend(option, parser_options.get());
      } else if (option.starts_with("--profile-file=")) {
        profile_file_ = option.substr(strlen("--profile-file=")).data();
        VLOG(compiler) << "dex2oat: profile file is " << profile_file_;
      } else if (option == "--no-profile-file") {
        // No profile
      } else if (option == "--host") {
        is_host_ = true;
      } else if (option == "--runtime-arg") {
        if (++i >= argc) {
          Usage("Missing required argument for --runtime-arg");
        }
        if (log_options) {
          LOG(INFO) << "dex2oat: option[" << i << "]=" << argv[i];
        }
        runtime_args_.push_back(argv[i]);
      } else if (option == "--dump-timing") {
        dump_timing_ = true;
      } else if (option == "--dump-passes") {
        dump_passes_ = true;
      } else if (option.starts_with("--dump-cfg=")) {
        dump_cfg_file_name_ = option.substr(strlen("--dump-cfg=")).data();
      } else if (option.starts_with("--dump-cfg-append")) {
        dump_cfg_append_ = true;
      } else if (option == "--dump-stats") {
        dump_stats_ = true;
      } else if (option.starts_with("--swap-file=")) {
        swap_file_name_ = option.substr(strlen("--swap-file=")).data();
      } else if (option.starts_with("--swap-fd=")) {
        ParseUintOption(option, "--swap-fd", &swap_fd_, Usage);
      } else if (option.starts_with("--app-image-file=")) {
        app_image_file_name_ = option.substr(strlen("--app-image-file=")).data();
      } else if (option.starts_with("--app-image-fd=")) {
        ParseUintOption(option, "--app-image-fd", &app_image_fd_, Usage);
      } else if (option.starts_with("--verbose-methods=")) {
        // TODO: rather than switch off compiler logging, make all VLOG(compiler) messages
        //       conditional on having verbost methods.
        gLogVerbosity.compiler = false;
        Split(option.substr(strlen("--verbose-methods=")).ToString(), ',', &verbose_methods_);
      } else if (option == "--multi-image") {
        multi_image = true;
      } else if (option.starts_with("--no-inline-from=")) {
        no_inline_from_string_ = option.substr(strlen("--no-inline-from=")).data();
      } else if (!compiler_options_->ParseCompilerOption(option, Usage)) {
        Usage("Unknown argument %s", option.data());
      }
    }

    ProcessOptions(parser_options.get(), multi_image);

    // Insert some compiler things.
    InsertCompileOptions(argc, argv);
  }

  // Check whether the oat output files are writable, and open them for later. Also open a swap
  // file, if a name is given.
  bool OpenFile() {
    bool create_file = oat_fd_ == -1;  // as opposed to using open file descriptor
    if (create_file) {
      for (const char* oat_filename : oat_filenames_) {
        std::unique_ptr<File> oat_file(OS::CreateEmptyFile(oat_filename));
        if (oat_file.get() == nullptr) {
          PLOG(ERROR) << "Failed to create oat file: " << oat_filename;
          return false;
        }
        if (create_file && fchmod(oat_file->Fd(), 0644) != 0) {
          PLOG(ERROR) << "Failed to make oat file world readable: " << oat_filename;
          oat_file->Erase();
          return false;
        }
        oat_files_.push_back(std::move(oat_file));
      }
    } else {
      std::unique_ptr<File> oat_file(new File(oat_fd_, oat_location_, true));
      oat_file->DisableAutoClose();
      if (oat_file->SetLength(0) != 0) {
        PLOG(WARNING) << "Truncating oat file " << oat_location_ << " failed.";
      }
      if (oat_file.get() == nullptr) {
        PLOG(ERROR) << "Failed to create oat file: " << oat_location_;
        return false;
      }
      if (create_file && fchmod(oat_file->Fd(), 0644) != 0) {
        PLOG(ERROR) << "Failed to make oat file world readable: " << oat_location_;
        oat_file->Erase();
        return false;
      }
      oat_filenames_.push_back(oat_location_.c_str());
      oat_files_.push_back(std::move(oat_file));
    }

    // Swap file handling.
    //
    // If the swap fd is not -1, we assume this is the file descriptor of an open but unlinked file
    // that we can use for swap.
    //
    // If the swap fd is -1 and we have a swap-file string, open the given file as a swap file. We
    // will immediately unlink to satisfy the swap fd assumption.
    if (swap_fd_ == -1 && !swap_file_name_.empty()) {
      std::unique_ptr<File> swap_file(OS::CreateEmptyFile(swap_file_name_.c_str()));
      if (swap_file.get() == nullptr) {
        PLOG(ERROR) << "Failed to create swap file: " << swap_file_name_;
        return false;
      }
      swap_fd_ = swap_file->Fd();
      swap_file->MarkUnchecked();     // We don't we to track this, it will be unlinked immediately.
      swap_file->DisableAutoClose();  // We'll handle it ourselves, the File object will be
                                      // released immediately.
      unlink(swap_file_name_.c_str());
    }
    return true;
  }

  void EraseOatFiles() {
    for (size_t i = 0; i < oat_files_.size(); ++i) {
      DCHECK(oat_files_[i].get() != nullptr);
      oat_files_[i]->Erase();
      oat_files_[i].reset();
    }
  }

  void Shutdown() {
    ScopedObjectAccess soa(Thread::Current());
    for (jobject dex_cache : dex_caches_) {
      soa.Env()->DeleteLocalRef(dex_cache);
    }
    dex_caches_.clear();
  }

  // Set up the environment for compilation. Includes starting the runtime and loading/opening the
  // boot class path.
  bool Setup() {
    TimingLogger::ScopedTiming t("dex2oat Setup", timings_);
    art::MemMap::Init();  // For ZipEntry::ExtractToMemMap.

    if (!PrepareImageClasses() || !PrepareCompiledClasses() || !PrepareCompiledMethods()) {
      return false;
    }

    verification_results_.reset(new VerificationResults(compiler_options_.get()));
    callbacks_.reset(new QuickCompilerCallbacks(
        verification_results_.get(),
        &method_inliner_map_,
        IsBootImage() ?
            CompilerCallbacks::CallbackMode::kCompileBootImage :
            CompilerCallbacks::CallbackMode::kCompileApp));

    RuntimeArgumentMap runtime_options;
    if (!PrepareRuntimeOptions(&runtime_options)) {
      return false;
    }

    {
      TimingLogger::ScopedTiming t_runtime("Create runtime", timings_);
      if (!CreateRuntime(std::move(runtime_options))) {
        return false;
      }
    }

    // Runtime::Create acquired the mutator_lock_ that is normally given away when we
    // Runtime::Start, give it away now so that we don't starve GC.
    Thread* self = Thread::Current();
    self->TransitionFromRunnableToSuspended(kNative);
    // If we're doing the image, override the compiler filter to force full compilation. Must be
    // done ahead of WellKnownClasses::Init that causes verification.  Note: doesn't force
    // compilation of class initializers.
    // Whilst we're in native take the opportunity to initialize well known classes.
    WellKnownClasses::Init(self->GetJniEnv());

    ClassLinker* const class_linker = Runtime::Current()->GetClassLinker();
    if (boot_image_filename_.empty()) {
      dex_files_ = class_linker->GetBootClassPath();
    } else {
      TimingLogger::ScopedTiming t_dex("Opening dex files", timings_);
      if (dex_filenames_.empty()) {
        ATRACE_BEGIN("Opening zip archive from file descriptor");
        std::string error_msg;
        std::unique_ptr<ZipArchive> zip_archive(ZipArchive::OpenFromFd(zip_fd_,
                                                                       zip_location_.c_str(),
                                                                       &error_msg));
        if (zip_archive.get() == nullptr) {
          LOG(ERROR) << "Failed to open zip from file descriptor for '" << zip_location_ << "': "
              << error_msg;
          return false;
        }
        if (!DexFile::OpenFromZip(*zip_archive.get(), zip_location_, &error_msg, &opened_dex_files_)) {
          LOG(ERROR) << "Failed to open dex from file descriptor for zip file '" << zip_location_
              << "': " << error_msg;
          return false;
        }
        for (auto& dex_file : opened_dex_files_) {
          dex_files_.push_back(dex_file.get());
        }
        ATRACE_END();
      } else {
        size_t failure_count = OpenDexFiles(dex_filenames_, dex_locations_, &opened_dex_files_);
        if (failure_count > 0) {
          LOG(ERROR) << "Failed to open some dex files: " << failure_count;
          return false;
        }
        for (auto& dex_file : opened_dex_files_) {
          dex_files_.push_back(dex_file.get());
        }
      }

      constexpr bool kSaveDexInput = false;
      if (kSaveDexInput) {
        SaveDexInput();
      }
    }
    // Ensure opened dex files are writable for dex-to-dex transformations. Also ensure that
    // the dex caches stay live since we don't want class unloading to occur during compilation.
    for (const auto& dex_file : dex_files_) {
      if (!dex_file->EnableWrite()) {
        PLOG(ERROR) << "Failed to make .dex file writeable '" << dex_file->GetLocation() << "'\n";
      }
      ScopedObjectAccess soa(self);
      dex_caches_.push_back(soa.AddLocalReference<jobject>(
          class_linker->RegisterDexFile(*dex_file, Runtime::Current()->GetLinearAlloc())));
      dex_file->CreateTypeLookupTable();
    }

    // If we use a swap file, ensure we are above the threshold to make it necessary.
    if (swap_fd_ != -1) {
      if (!UseSwap(IsBootImage(), dex_files_)) {
        close(swap_fd_);
        swap_fd_ = -1;
        VLOG(compiler) << "Decided to run without swap.";
      } else {
        LOG(INFO) << "Large app, accepted running with swap.";
      }
    }
    // Note that dex2oat won't close the swap_fd_. The compiler driver's swap space will do that.

    /*
     * If we're not in interpret-only or verify-none mode, go ahead and compile small applications.
     * Don't bother to check if we're doing the image.
     */
    if (!IsBootImage() &&
        compiler_options_->IsCompilationEnabled() &&
        compiler_kind_ == Compiler::kQuick) {
      size_t num_methods = 0;
      for (size_t i = 0; i != dex_files_.size(); ++i) {
        const DexFile* dex_file = dex_files_[i];
        CHECK(dex_file != nullptr);
        num_methods += dex_file->NumMethodIds();
      }
      if (num_methods <= compiler_options_->GetNumDexMethodsThreshold()) {
        compiler_options_->SetCompilerFilter(CompilerOptions::kSpeed);
        VLOG(compiler) << "Below method threshold, compiling anyways";
      }
    }

    // Organize inputs, handling multi-dex and multiple oat file outputs.
    CreateDexOatMappings();

    return true;
  }

  void CreateDexOatMappings() {
    if (oat_files_.size() > 1) {
      size_t index = 0;
      for (size_t i = 0; i < oat_files_.size(); ++i) {
        std::vector<const DexFile*> dex_files = { 1, dex_files_[index] };
        dex_file_oat_filename_map_.emplace(dex_files_[index], oat_filenames_[i]);
        index++;
        while (index < dex_files_.size() &&
            (dex_files_[index]->GetBaseLocation() == dex_files_[index - 1]->GetBaseLocation())) {
          dex_file_oat_filename_map_.emplace(dex_files_[index], oat_filenames_[i]);
          dex_files.push_back(dex_files_[index]);
          index++;
        }
        dex_files_per_oat_file_.push_back(std::move(dex_files));
      }
    } else {
      dex_files_per_oat_file_.push_back(dex_files_);
      for (const DexFile* dex_file : dex_files_) {
        dex_file_oat_filename_map_.emplace(dex_file, oat_filenames_[0]);
      }
    }
  }

  // Create and invoke the compiler driver. This will compile all the dex files.
  void Compile() {
    TimingLogger::ScopedTiming t("dex2oat Compile", timings_);
    compiler_phases_timings_.reset(new CumulativeLogger("compilation times"));

    // Handle and ClassLoader creation needs to come after Runtime::Create
    jobject class_loader = nullptr;
    jobject class_path_class_loader = nullptr;
    Thread* self = Thread::Current();

    if (!boot_image_filename_.empty()) {
      ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
      OpenClassPathFiles(runtime_->GetClassPathString(), dex_files_, &class_path_files_);
      ScopedObjectAccess soa(self);

      // Classpath: first the class-path given.
      std::vector<const DexFile*> class_path_files = MakeNonOwningPointerVector(class_path_files_);

      // Store the classpath we have right now.
      key_value_store_->Put(OatHeader::kClassPathKey,
                            OatFile::EncodeDexFileDependencies(class_path_files));

      class_path_class_loader = class_linker->CreatePathClassLoader(self,
                                                                    class_path_files,
                                                                    nullptr);

      // Class path loader as parent so that we'll resolve there first.
      class_loader = class_linker->CreatePathClassLoader(self, dex_files_, class_path_class_loader);
    }

    // Find the dex file we should not inline from.

    // For now, on the host always have core-oj removed.
    if (!kIsTargetBuild && no_inline_from_string_.empty()) {
      no_inline_from_string_ = "core-oj";
    }

    if (!no_inline_from_string_.empty()) {
      ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
      std::vector<const DexFile*> class_path_files = MakeNonOwningPointerVector(class_path_files_);
      std::vector<const std::vector<const DexFile*>*> dex_file_vectors = {
          &class_linker->GetBootClassPath(),
          &class_path_files,
          &dex_files_
      };
      for (const std::vector<const DexFile*>* dex_file_vector : dex_file_vectors) {
        if (dex_file_vector == nullptr) {
          continue;
        }

        bool found = false;

        for (const DexFile* dex_file : *dex_file_vector) {
          // Try the complete location first.
          found = no_inline_from_string_ == dex_file->GetLocation();
          // The try just the name.
          if (!found) {
            size_t last_slash = dex_file->GetLocation().rfind('/');
            if (last_slash != std::string::npos) {
              found = StartsWith(dex_file->GetLocation().substr(last_slash + 1),
                                 no_inline_from_string_.c_str());
            }
          }

          if (found) {
            VLOG(compiler) << "Disabling inlining from " << dex_file->GetLocation();
            compiler_options_->no_inline_from_ = dex_file;
            break;
          }
        }

        if (found) {
          break;
        }
      }
    }

    if (IsBootImage() && image_filenames_.size() > 1) {
      // If we're compiling the boot image, store the boot classpath into the Key-Value store. If
      // the image filename was adapted (e.g., for our tests), we need to change this here, too. We
      // need this for the multi-image case.
      std::ostringstream bootcp_oss;
      bool first_bootcp = true;
      for (size_t i = 0; i < dex_locations_.size(); ++i) {
        if (!first_bootcp) {
          bootcp_oss << ":";
        }

        std::string dex_loc = dex_locations_[i];
        std::string image_filename = image_filenames_[i];

        // Use the dex_loc path, but the image_filename name.
        size_t dex_last_slash = dex_loc.rfind('/');
        size_t image_last_slash = image_filename.rfind('/');
        if (dex_last_slash == std::string::npos) {
          dex_loc = image_filename.substr(image_last_slash + 1);
        } else {
          dex_loc = dex_loc.substr(0, dex_last_slash + 1) +
              image_filename.substr(image_last_slash + 1);
        }

        // Image filenames already end with .art, no need to replace.

        bootcp_oss << dex_loc;
        first_bootcp = false;
      }
      key_value_store_->Put(OatHeader::kBootClassPath, bootcp_oss.str());
    }

    driver_.reset(new CompilerDriver(compiler_options_.get(),
                                     verification_results_.get(),
                                     &method_inliner_map_,
                                     compiler_kind_,
                                     instruction_set_,
                                     instruction_set_features_.get(),
                                     IsBootImage(),
                                     image_classes_.release(),
                                     compiled_classes_.release(),
                                     nullptr,
                                     thread_count_,
                                     dump_stats_,
                                     dump_passes_,
                                     dump_cfg_file_name_,
                                     dump_cfg_append_,
                                     compiler_phases_timings_.get(),
                                     swap_fd_,
                                     profile_file_,
                                     &dex_file_oat_filename_map_));

    driver_->SetDexFilesForOatFile(dex_files_);
    driver_->CompileAll(class_loader, dex_files_, timings_);
  }

  // TODO: Update comments about how this works for multi image. b/26317072
  // Notes on the interleaving of creating the image and oat file to
  // ensure the references between the two are correct.
  //
  // Currently we have a memory layout that looks something like this:
  //
  // +--------------+
  // | image        |
  // +--------------+
  // | boot oat     |
  // +--------------+
  // | alloc spaces |
  // +--------------+
  //
  // There are several constraints on the loading of the image and boot.oat.
  //
  // 1. The image is expected to be loaded at an absolute address and
  // contains Objects with absolute pointers within the image.
  //
  // 2. There are absolute pointers from Methods in the image to their
  // code in the oat.
  //
  // 3. There are absolute pointers from the code in the oat to Methods
  // in the image.
  //
  // 4. There are absolute pointers from code in the oat to other code
  // in the oat.
  //
  // To get this all correct, we go through several steps.
  //
  // 1. We prepare offsets for all data in the oat file and calculate
  // the oat data size and code size. During this stage, we also set
  // oat code offsets in methods for use by the image writer.
  //
  // 2. We prepare offsets for the objects in the image and calculate
  // the image size.
  //
  // 3. We create the oat file. Originally this was just our own proprietary
  // file but now it is contained within an ELF dynamic object (aka an .so
  // file). Since we know the image size and oat data size and code size we
  // can prepare the ELF headers and we then know the ELF memory segment
  // layout and we can now resolve all references. The compiler provides
  // LinkerPatch information in each CompiledMethod and we resolve these,
  // using the layout information and image object locations provided by
  // image writer, as we're writing the method code.
  //
  // 4. We create the image file. It needs to know where the oat file
  // will be loaded after itself. Originally when oat file was simply
  // memory mapped so we could predict where its contents were based
  // on the file size. Now that it is an ELF file, we need to inspect
  // the ELF file to understand the in memory segment layout including
  // where the oat header is located within.
  // TODO: We could just remember this information from step 3.
  //
  // 5. We fixup the ELF program headers so that dlopen will try to
  // load the .so at the desired location at runtime by offsetting the
  // Elf32_Phdr.p_vaddr values by the desired base address.
  // TODO: Do this in step 3. We already know the layout there.
  //
  // Steps 1.-3. are done by the CreateOatFile() above, steps 4.-5.
  // are done by the CreateImageFile() below.

  // Write out the generated code part. Calls the OatWriter and ElfBuilder. Also prepares the
  // ImageWriter, if necessary.
  // Note: Flushing (and closing) the file is the caller's responsibility, except for the failure
  //       case (when the file will be explicitly erased).
  bool CreateOatFiles() {
    CHECK(key_value_store_.get() != nullptr);

    TimingLogger::ScopedTiming t("dex2oat Oat", timings_);

    std::vector<std::unique_ptr<OatWriter>> oat_writers;
    {
      TimingLogger::ScopedTiming t2("dex2oat OatWriter", timings_);
      std::string image_file_location;
      uint32_t image_file_location_oat_checksum = 0;
      uintptr_t image_file_location_oat_data_begin = 0;
      int32_t image_patch_delta = 0;

      if (app_image_ && image_base_ == 0) {
        std::vector<gc::space::ImageSpace*> image_spaces =
            Runtime::Current()->GetHeap()->GetBootImageSpaces();
        for (gc::space::ImageSpace* image_space : image_spaces) {
          // TODO: IS THIS IN ORDER? JUST TAKE THE LAST ONE?
          image_base_ = std::max(image_base_, RoundUp(
              reinterpret_cast<uintptr_t>(image_space->GetImageHeader().GetOatFileEnd()),
              kPageSize));
        }
        VLOG(compiler) << "App image base=" << reinterpret_cast<void*>(image_base_);
      }

      if (IsImage()) {
        PrepareImageWriter(image_base_);
      }

      if (!IsBootImage()) {
        TimingLogger::ScopedTiming t3("Loading image checksum", timings_);
        std::vector<gc::space::ImageSpace*> image_spaces =
            Runtime::Current()->GetHeap()->GetBootImageSpaces();
        image_file_location_oat_checksum = image_spaces[0]->GetImageHeader().GetOatChecksum();
        image_file_location_oat_data_begin =
            reinterpret_cast<uintptr_t>(image_spaces[0]->GetImageHeader().GetOatDataBegin());
        image_patch_delta = image_spaces[0]->GetImageHeader().GetPatchDelta();
        std::vector<std::string> image_filenames;
        for (const gc::space::ImageSpace* image_space : image_spaces) {
          image_filenames.push_back(image_space->GetImageFilename());
        }
        image_file_location = Join(image_filenames, ':');
      }

      if (!image_file_location.empty()) {
        key_value_store_->Put(OatHeader::kImageLocationKey, image_file_location);
      }

      for (size_t i = 0; i < oat_files_.size(); ++i) {
        std::vector<const DexFile*>& dex_files = dex_files_per_oat_file_[i];
        std::unique_ptr<OatWriter> oat_writer(new OatWriter(dex_files,
                                                            image_file_location_oat_checksum,
                                                            image_file_location_oat_data_begin,
                                                            image_patch_delta,
                                                            driver_.get(),
                                                            image_writer_.get(),
                                                            IsBootImage(),
                                                            timings_,
                                                            key_value_store_.get()));
        oat_writers.push_back(std::move(oat_writer));
      }
    }

    if (IsImage()) {
      // The OatWriter constructor has already updated offsets in methods and we need to
      // prepare method offsets in the image address space for direct method patching.
      TimingLogger::ScopedTiming t2("dex2oat Prepare image address space", timings_);
      if (!image_writer_->PrepareImageAddressSpace()) {
        LOG(ERROR) << "Failed to prepare image address space.";
        return false;
      }
    }

    {
      TimingLogger::ScopedTiming t2("dex2oat Write ELF", timings_);
      for (size_t i = 0; i < oat_files_.size(); ++i) {
        std::unique_ptr<File>& oat_file = oat_files_[i];
        std::unique_ptr<OatWriter>& oat_writer = oat_writers[i];
        std::unique_ptr<ElfWriter> elf_writer =
            CreateElfWriterQuick(instruction_set_, compiler_options_.get(), oat_file.get());

        elf_writer->Start();

        OutputStream* rodata = elf_writer->StartRoData();
        if (!oat_writer->WriteRodata(rodata)) {
          LOG(ERROR) << "Failed to write .rodata section to the ELF file " << oat_file->GetPath();
          return false;
        }
        elf_writer->EndRoData(rodata);

        OutputStream* text = elf_writer->StartText();
        if (!oat_writer->WriteCode(text)) {
          LOG(ERROR) << "Failed to write .text section to the ELF file " << oat_file->GetPath();
          return false;
        }
        elf_writer->EndText(text);

        elf_writer->SetBssSize(oat_writer->GetBssSize());
        elf_writer->WriteDynamicSection();
        elf_writer->WriteDebugInfo(oat_writer->GetMethodDebugInfo());
        elf_writer->WritePatchLocations(oat_writer->GetAbsolutePatchLocations());

        if (!elf_writer->End()) {
          LOG(ERROR) << "Failed to write ELF file " << oat_file->GetPath();
          return false;
        }

        // Flush the oat file.
        if (oat_files_[i] != nullptr) {
          if (oat_files_[i]->Flush() != 0) {
            PLOG(ERROR) << "Failed to flush oat file: " << oat_filenames_[i];
            oat_files_[i]->Erase();
            return false;
          }
        }

        if (IsImage()) {
          // Update oat estimates.
          UpdateImageWriter(i);
        }

        VLOG(compiler) << "Oat file written successfully: " << oat_filenames_[i];
      }
    }

    return true;
  }

  // If we are compiling an image, invoke the image creation routine. Else just skip.
  bool HandleImage() {
    if (IsImage()) {
      TimingLogger::ScopedTiming t("dex2oat ImageWriter", timings_);
      if (!CreateImageFile()) {
        return false;
      }
      VLOG(compiler) << "Images written successfully";
    }
    return true;
  }

  // Create a copy from stripped to unstripped.
  bool CopyStrippedToUnstripped() {
    for (size_t i = 0; i < oat_unstripped_.size(); ++i) {
      // If we don't want to strip in place, copy from stripped location to unstripped location.
      // We need to strip after image creation because FixupElf needs to use .strtab.
      if (strcmp(oat_unstripped_[i], oat_filenames_[i]) != 0) {
        // If the oat file is still open, flush it.
        if (oat_files_[i].get() != nullptr && oat_files_[i]->IsOpened()) {
          if (!FlushCloseOatFile(i)) {
            return false;
          }
        }

        TimingLogger::ScopedTiming t("dex2oat OatFile copy", timings_);
        std::unique_ptr<File> in(OS::OpenFileForReading(oat_filenames_[i]));
        std::unique_ptr<File> out(OS::CreateEmptyFile(oat_unstripped_[i]));
        size_t buffer_size = 8192;
        std::unique_ptr<uint8_t[]> buffer(new uint8_t[buffer_size]);
        while (true) {
          int bytes_read = TEMP_FAILURE_RETRY(read(in->Fd(), buffer.get(), buffer_size));
          if (bytes_read <= 0) {
            break;
          }
          bool write_ok = out->WriteFully(buffer.get(), bytes_read);
          CHECK(write_ok);
        }
        if (out->FlushCloseOrErase() != 0) {
          PLOG(ERROR) << "Failed to flush and close copied oat file: " << oat_unstripped_[i];
          return false;
        }
        VLOG(compiler) << "Oat file copied successfully (unstripped): " << oat_unstripped_[i];
      }
    }
    return true;
  }

  bool FlushOatFiles() {
    TimingLogger::ScopedTiming t2("dex2oat Flush ELF", timings_);
    for (size_t i = 0; i < oat_files_.size(); ++i) {
      if (oat_files_[i].get() != nullptr) {
        if (oat_files_[i]->Flush() != 0) {
          PLOG(ERROR) << "Failed to flush oat file: " << oat_filenames_[i];
          oat_files_[i]->Erase();
          return false;
        }
      }
    }
    return true;
  }

  bool FlushCloseOatFile(size_t i) {
    if (oat_files_[i].get() != nullptr) {
      std::unique_ptr<File> tmp(oat_files_[i].release());
      if (tmp->FlushCloseOrErase() != 0) {
        PLOG(ERROR) << "Failed to flush and close oat file: " << oat_filenames_[i];
        return false;
      }
    }
    return true;
  }

  bool FlushCloseOatFiles() {
    bool result = true;
    for (size_t i = 0; i < oat_files_.size(); ++i) {
      result &= FlushCloseOatFile(i);
    }
    return result;
  }

  void DumpTiming() {
    if (dump_timing_ || (dump_slow_timing_ && timings_->GetTotalNs() > MsToNs(1000))) {
      LOG(INFO) << Dumpable<TimingLogger>(*timings_);
    }
    if (dump_passes_) {
      LOG(INFO) << Dumpable<CumulativeLogger>(*driver_->GetTimingsLogger());
    }
  }

  CompilerOptions* GetCompilerOptions() const {
    return compiler_options_.get();
  }

  bool IsImage() const {
    return IsAppImage() || IsBootImage();
  }

  bool IsAppImage() const {
    return app_image_;
  }

  bool IsBootImage() const {
    return boot_image_;
  }

  bool IsHost() const {
    return is_host_;
  }

 private:
  template <typename T>
  static std::vector<T*> MakeNonOwningPointerVector(const std::vector<std::unique_ptr<T>>& src) {
    std::vector<T*> result;
    result.reserve(src.size());
    for (const std::unique_ptr<T>& t : src) {
      result.push_back(t.get());
    }
    return result;
  }

  static size_t OpenDexFiles(const std::vector<const char*>& dex_filenames,
                             const std::vector<const char*>& dex_locations,
                             std::vector<std::unique_ptr<const DexFile>>* dex_files) {
    DCHECK(dex_files != nullptr) << "OpenDexFiles out-param is nullptr";
    size_t failure_count = 0;
    for (size_t i = 0; i < dex_filenames.size(); i++) {
      const char* dex_filename = dex_filenames[i];
      const char* dex_location = dex_locations[i];
      ATRACE_BEGIN(StringPrintf("Opening dex file '%s'", dex_filenames[i]).c_str());
      std::string error_msg;
      if (!OS::FileExists(dex_filename)) {
        LOG(WARNING) << "Skipping non-existent dex file '" << dex_filename << "'";
        continue;
      }
      if (!DexFile::Open(dex_filename, dex_location, &error_msg, dex_files)) {
        LOG(WARNING) << "Failed to open .dex from file '" << dex_filename << "': " << error_msg;
        ++failure_count;
      }
      ATRACE_END();
    }
    return failure_count;
  }

  // Returns true if dex_files has a dex with the named location. We compare canonical locations,
  // so that relative and absolute paths will match. Not caching for the dex_files isn't very
  // efficient, but under normal circumstances the list is neither large nor is this part too
  // sensitive.
  static bool DexFilesContains(const std::vector<const DexFile*>& dex_files,
                               const std::string& location) {
    std::string canonical_location(DexFile::GetDexCanonicalLocation(location.c_str()));
    for (size_t i = 0; i < dex_files.size(); ++i) {
      if (DexFile::GetDexCanonicalLocation(dex_files[i]->GetLocation().c_str()) ==
          canonical_location) {
        return true;
      }
    }
    return false;
  }

  // Appends to opened_dex_files any elements of class_path that dex_files
  // doesn't already contain. This will open those dex files as necessary.
  static void OpenClassPathFiles(const std::string& class_path,
                                 std::vector<const DexFile*> dex_files,
                                 std::vector<std::unique_ptr<const DexFile>>* opened_dex_files) {
    DCHECK(opened_dex_files != nullptr) << "OpenClassPathFiles out-param is nullptr";
    std::vector<std::string> parsed;
    Split(class_path, ':', &parsed);
    // Take Locks::mutator_lock_ so that lock ordering on the ClassLinker::dex_lock_ is maintained.
    ScopedObjectAccess soa(Thread::Current());
    for (size_t i = 0; i < parsed.size(); ++i) {
      if (DexFilesContains(dex_files, parsed[i])) {
        continue;
      }
      std::string error_msg;
      if (!DexFile::Open(parsed[i].c_str(), parsed[i].c_str(), &error_msg, opened_dex_files)) {
        LOG(WARNING) << "Failed to open dex file '" << parsed[i] << "': " << error_msg;
      }
    }
  }

  bool PrepareImageClasses() {
    // If --image-classes was specified, calculate the full list of classes to include in the image.
    if (image_classes_filename_ != nullptr) {
      image_classes_ =
          ReadClasses(image_classes_zip_filename_, image_classes_filename_, "image");
      if (image_classes_ == nullptr) {
        return false;
      }
    } else if (IsBootImage()) {
      image_classes_.reset(new std::unordered_set<std::string>);
    }
    return true;
  }

  bool PrepareCompiledClasses() {
    // If --compiled-classes was specified, calculate the full list of classes to compile in the
    // image.
    if (compiled_classes_filename_ != nullptr) {
      compiled_classes_ =
          ReadClasses(compiled_classes_zip_filename_, compiled_classes_filename_, "compiled");
      if (compiled_classes_ == nullptr) {
        return false;
      }
    } else {
      compiled_classes_.reset(nullptr);  // By default compile everything.
    }
    return true;
  }

  static std::unique_ptr<std::unordered_set<std::string>> ReadClasses(const char* zip_filename,
                                                                      const char* classes_filename,
                                                                      const char* tag) {
    std::unique_ptr<std::unordered_set<std::string>> classes;
    std::string error_msg;
    if (zip_filename != nullptr) {
      classes.reset(ReadImageClassesFromZip(zip_filename, classes_filename, &error_msg));
    } else {
      classes.reset(ReadImageClassesFromFile(classes_filename));
    }
    if (classes == nullptr) {
      LOG(ERROR) << "Failed to create list of " << tag << " classes from '"
                 << classes_filename << "': " << error_msg;
    }
    return classes;
  }

  bool PrepareCompiledMethods() {
    // If --compiled-methods was specified, read the methods to compile from the given file(s).
    if (compiled_methods_filename_ != nullptr) {
      std::string error_msg;
      if (compiled_methods_zip_filename_ != nullptr) {
        compiled_methods_.reset(ReadCommentedInputFromZip(compiled_methods_zip_filename_,
                                                          compiled_methods_filename_,
                                                          nullptr,            // No post-processing.
                                                          &error_msg));
      } else {
        compiled_methods_.reset(ReadCommentedInputFromFile(compiled_methods_filename_,
                                                           nullptr));         // No post-processing.
      }
      if (compiled_methods_.get() == nullptr) {
        LOG(ERROR) << "Failed to create list of compiled methods from '"
            << compiled_methods_filename_ << "': " << error_msg;
        return false;
      }
    } else {
      compiled_methods_.reset(nullptr);  // By default compile everything.
    }
    return true;
  }

  void SaveDexInput() {
    for (size_t i = 0; i < dex_files_.size(); ++i) {
      const DexFile* dex_file = dex_files_[i];
      std::string tmp_file_name(StringPrintf("/data/local/tmp/dex2oat.%d.%zd.dex",
                                             getpid(), i));
      std::unique_ptr<File> tmp_file(OS::CreateEmptyFile(tmp_file_name.c_str()));
      if (tmp_file.get() == nullptr) {
        PLOG(ERROR) << "Failed to open file " << tmp_file_name
            << ". Try: adb shell chmod 777 /data/local/tmp";
        continue;
      }
      // This is just dumping files for debugging. Ignore errors, and leave remnants.
      UNUSED(tmp_file->WriteFully(dex_file->Begin(), dex_file->Size()));
      UNUSED(tmp_file->Flush());
      UNUSED(tmp_file->Close());
      LOG(INFO) << "Wrote input to " << tmp_file_name;
    }
  }

  bool PrepareRuntimeOptions(RuntimeArgumentMap* runtime_options) {
    RuntimeOptions raw_options;
    if (boot_image_filename_.empty()) {
      std::string boot_class_path = "-Xbootclasspath:";
      boot_class_path += Join(dex_filenames_, ':');
      raw_options.push_back(std::make_pair(boot_class_path, nullptr));
      std::string boot_class_path_locations = "-Xbootclasspath-locations:";
      boot_class_path_locations += Join(dex_locations_, ':');
      raw_options.push_back(std::make_pair(boot_class_path_locations, nullptr));
    } else {
      std::string boot_image_option = "-Ximage:";
      boot_image_option += boot_image_filename_;
      raw_options.push_back(std::make_pair(boot_image_option, nullptr));
    }
    for (size_t i = 0; i < runtime_args_.size(); i++) {
      raw_options.push_back(std::make_pair(runtime_args_[i], nullptr));
    }

    raw_options.push_back(std::make_pair("compilercallbacks", callbacks_.get()));
    raw_options.push_back(
        std::make_pair("imageinstructionset", GetInstructionSetString(instruction_set_)));

    // Only allow no boot image for the runtime if we're compiling one. When we compile an app,
    // we don't want fallback mode, it will abort as we do not push a boot classpath (it might
    // have been stripped in preopting, anyways).
    if (!IsBootImage()) {
      raw_options.push_back(std::make_pair("-Xno-dex-file-fallback", nullptr));
    }
    // Disable libsigchain. We don't don't need it during compilation and it prevents us
    // from getting a statically linked version of dex2oat (because of dlsym and RTLD_NEXT).
    raw_options.push_back(std::make_pair("-Xno-sig-chain", nullptr));

    if (!Runtime::ParseOptions(raw_options, false, runtime_options)) {
      LOG(ERROR) << "Failed to parse runtime options";
      return false;
    }
    return true;
  }

  // Create a runtime necessary for compilation.
  bool CreateRuntime(RuntimeArgumentMap&& runtime_options)
      SHARED_TRYLOCK_FUNCTION(true, Locks::mutator_lock_) {
    if (!Runtime::Create(std::move(runtime_options))) {
      LOG(ERROR) << "Failed to create runtime";
      return false;
    }
    runtime_.reset(Runtime::Current());
    runtime_->SetInstructionSet(instruction_set_);
    for (int i = 0; i < Runtime::kLastCalleeSaveType; i++) {
      Runtime::CalleeSaveType type = Runtime::CalleeSaveType(i);
      if (!runtime_->HasCalleeSaveMethod(type)) {
        runtime_->SetCalleeSaveMethod(runtime_->CreateCalleeSaveMethod(), type);
      }
    }
    runtime_->GetClassLinker()->FixupDexCaches(runtime_->GetResolutionMethod());

    // Initialize maps for unstarted runtime. This needs to be here, as running clinits needs this
    // set up.
    interpreter::UnstartedRuntime::Initialize();

    runtime_->GetClassLinker()->RunRootClinits();

    return true;
  }

  void PrepareImageWriter(uintptr_t image_base) {
    DCHECK(IsImage());
    image_writer_.reset(new ImageWriter(*driver_,
                                        image_base,
                                        compiler_options_->GetCompilePic(),
                                        IsAppImage(),
                                        image_storage_mode_,
                                        oat_filenames_,
                                        dex_file_oat_filename_map_));
  }

  // Let the ImageWriter write the image files. If we do not compile PIC, also fix up the oat files.
  bool CreateImageFile()
      REQUIRES(!Locks::mutator_lock_) {
    CHECK(image_writer_ != nullptr);
    if (!IsBootImage()) {
      image_filenames_.push_back(app_image_file_name_.c_str());
    }
    if (!image_writer_->Write(app_image_fd_, image_filenames_, oat_filenames_)) {
      LOG(ERROR) << "Failure during image file creation";
      return false;
    }

    // We need the OatDataBegin entries.
    std::map<const char*, uintptr_t> oat_data_begins;
    for (const char* oat_filename : oat_filenames_) {
      oat_data_begins.emplace(oat_filename, image_writer_->GetOatDataBegin(oat_filename));
    }
    // Destroy ImageWriter before doing FixupElf.
    image_writer_.reset();

    for (const char* oat_filename : oat_filenames_) {
      // Do not fix up the ELF file if we are --compile-pic or compiling the app image
      if (!compiler_options_->GetCompilePic() && IsBootImage()) {
        std::unique_ptr<File> oat_file(OS::OpenFileReadWrite(oat_filename));
        if (oat_file.get() == nullptr) {
          PLOG(ERROR) << "Failed to open ELF file: " << oat_filename;
          return false;
        }

        uintptr_t oat_data_begin = oat_data_begins.find(oat_filename)->second;

        if (!ElfWriter::Fixup(oat_file.get(), oat_data_begin)) {
          oat_file->Erase();
          LOG(ERROR) << "Failed to fixup ELF file " << oat_file->GetPath();
          return false;
        }

        if (oat_file->FlushCloseOrErase()) {
          PLOG(ERROR) << "Failed to flush and close fixed ELF file " << oat_file->GetPath();
          return false;
        }
      }
    }

    return true;
  }

  // Reads the class names (java.lang.Object) and returns a set of descriptors (Ljava/lang/Object;)
  static std::unordered_set<std::string>* ReadImageClassesFromFile(
      const char* image_classes_filename) {
    std::function<std::string(const char*)> process = DotToDescriptor;
    return ReadCommentedInputFromFile(image_classes_filename, &process);
  }

  // Reads the class names (java.lang.Object) and returns a set of descriptors (Ljava/lang/Object;)
  static std::unordered_set<std::string>* ReadImageClassesFromZip(
        const char* zip_filename,
        const char* image_classes_filename,
        std::string* error_msg) {
    std::function<std::string(const char*)> process = DotToDescriptor;
    return ReadCommentedInputFromZip(zip_filename, image_classes_filename, &process, error_msg);
  }

  // Read lines from the given file, dropping comments and empty lines. Post-process each line with
  // the given function.
  static std::unordered_set<std::string>* ReadCommentedInputFromFile(
      const char* input_filename, std::function<std::string(const char*)>* process) {
    std::unique_ptr<std::ifstream> input_file(new std::ifstream(input_filename, std::ifstream::in));
    if (input_file.get() == nullptr) {
      LOG(ERROR) << "Failed to open input file " << input_filename;
      return nullptr;
    }
    std::unique_ptr<std::unordered_set<std::string>> result(
        ReadCommentedInputStream(*input_file, process));
    input_file->close();
    return result.release();
  }

  // Read lines from the given file from the given zip file, dropping comments and empty lines.
  // Post-process each line with the given function.
  static std::unordered_set<std::string>* ReadCommentedInputFromZip(
      const char* zip_filename,
      const char* input_filename,
      std::function<std::string(const char*)>* process,
      std::string* error_msg) {
    std::unique_ptr<ZipArchive> zip_archive(ZipArchive::Open(zip_filename, error_msg));
    if (zip_archive.get() == nullptr) {
      return nullptr;
    }
    std::unique_ptr<ZipEntry> zip_entry(zip_archive->Find(input_filename, error_msg));
    if (zip_entry.get() == nullptr) {
      *error_msg = StringPrintf("Failed to find '%s' within '%s': %s", input_filename,
                                zip_filename, error_msg->c_str());
      return nullptr;
    }
    std::unique_ptr<MemMap> input_file(zip_entry->ExtractToMemMap(zip_filename,
                                                                  input_filename,
                                                                  error_msg));
    if (input_file.get() == nullptr) {
      *error_msg = StringPrintf("Failed to extract '%s' from '%s': %s", input_filename,
                                zip_filename, error_msg->c_str());
      return nullptr;
    }
    const std::string input_string(reinterpret_cast<char*>(input_file->Begin()),
                                   input_file->Size());
    std::istringstream input_stream(input_string);
    return ReadCommentedInputStream(input_stream, process);
  }

  // Read lines from the given stream, dropping comments and empty lines. Post-process each line
  // with the given function.
  static std::unordered_set<std::string>* ReadCommentedInputStream(
      std::istream& in_stream,
      std::function<std::string(const char*)>* process) {
    std::unique_ptr<std::unordered_set<std::string>> image_classes(
        new std::unordered_set<std::string>);
    while (in_stream.good()) {
      std::string dot;
      std::getline(in_stream, dot);
      if (StartsWith(dot, "#") || dot.empty()) {
        continue;
      }
      if (process != nullptr) {
        std::string descriptor((*process)(dot.c_str()));
        image_classes->insert(descriptor);
      } else {
        image_classes->insert(dot);
      }
    }
    return image_classes.release();
  }

  void LogCompletionTime() {
    // Note: when creation of a runtime fails, e.g., when trying to compile an app but when there
    //       is no image, there won't be a Runtime::Current().
    // Note: driver creation can fail when loading an invalid dex file.
    LOG(INFO) << "dex2oat took " << PrettyDuration(NanoTime() - start_ns_)
              << " (threads: " << thread_count_ << ") "
              << ((Runtime::Current() != nullptr && driver_ != nullptr) ?
                  driver_->GetMemoryUsageString(kIsDebugBuild || VLOG_IS_ON(compiler)) :
                  "");
  }

  std::string StripIsaFrom(const char* image_filename, InstructionSet isa) {
    std::string res(image_filename);
    size_t last_slash = res.rfind('/');
    if (last_slash == std::string::npos || last_slash == 0) {
      return res;
    }
    size_t penultimate_slash = res.rfind('/', last_slash - 1);
    if (penultimate_slash == std::string::npos) {
      return res;
    }
    // Check that the string in-between is the expected one.
    if (res.substr(penultimate_slash + 1, last_slash - penultimate_slash - 1) !=
            GetInstructionSetString(isa)) {
      LOG(WARNING) << "Unexpected string when trying to strip isa: " << res;
      return res;
    }
    return res.substr(0, penultimate_slash) + res.substr(last_slash);
  }

  // Update the estimate for the oat file with the given index.
  void UpdateImageWriter(size_t index) {
    DCHECK(image_writer_ != nullptr);
    DCHECK_LT(index, oat_filenames_.size());

    image_writer_->UpdateOatFile(oat_filenames_[index]);
  }

  std::unique_ptr<CompilerOptions> compiler_options_;
  Compiler::Kind compiler_kind_;

  InstructionSet instruction_set_;
  std::unique_ptr<const InstructionSetFeatures> instruction_set_features_;

  std::unique_ptr<SafeMap<std::string, std::string> > key_value_store_;

  std::unique_ptr<VerificationResults> verification_results_;

  DexFileToMethodInlinerMap method_inliner_map_;
  std::unique_ptr<QuickCompilerCallbacks> callbacks_;

  // Ownership for the class path files.
  std::vector<std::unique_ptr<const DexFile>> class_path_files_;

  std::unique_ptr<Runtime> runtime_;

  size_t thread_count_;
  uint64_t start_ns_;
  std::unique_ptr<WatchDog> watchdog_;
  std::vector<std::unique_ptr<File>> oat_files_;
  std::string oat_location_;
  std::vector<const char*> oat_filenames_;
  std::vector<const char*> oat_unstripped_;
  int oat_fd_;
  std::vector<const char*> dex_filenames_;
  std::vector<const char*> dex_locations_;
  int zip_fd_;
  std::string zip_location_;
  std::string boot_image_filename_;
  std::vector<const char*> runtime_args_;
  std::vector<const char*> image_filenames_;
  uintptr_t image_base_;
  const char* image_classes_zip_filename_;
  const char* image_classes_filename_;
  ImageHeader::StorageMode image_storage_mode_;
  const char* compiled_classes_zip_filename_;
  const char* compiled_classes_filename_;
  const char* compiled_methods_zip_filename_;
  const char* compiled_methods_filename_;
  std::unique_ptr<std::unordered_set<std::string>> image_classes_;
  std::unique_ptr<std::unordered_set<std::string>> compiled_classes_;
  std::unique_ptr<std::unordered_set<std::string>> compiled_methods_;
  bool app_image_;
  bool boot_image_;
  bool is_host_;
  std::string android_root_;
  std::vector<const DexFile*> dex_files_;
  std::string no_inline_from_string_;
  std::vector<jobject> dex_caches_;
  std::vector<std::unique_ptr<const DexFile>> opened_dex_files_;

  std::unique_ptr<ImageWriter> image_writer_;
  std::unique_ptr<CompilerDriver> driver_;

  std::vector<std::string> verbose_methods_;
  bool dump_stats_;
  bool dump_passes_;
  bool dump_timing_;
  bool dump_slow_timing_;
  std::string dump_cfg_file_name_;
  bool dump_cfg_append_;
  std::string swap_file_name_;
  int swap_fd_;
  std::string app_image_file_name_;
  int app_image_fd_;
  std::string profile_file_;  // Profile file to use
  TimingLogger* timings_;
  std::unique_ptr<CumulativeLogger> compiler_phases_timings_;
  std::vector<std::vector<const DexFile*>> dex_files_per_oat_file_;
  std::unordered_map<const DexFile*, const char*> dex_file_oat_filename_map_;

  // Backing storage.
  std::vector<std::string> char_backing_storage_;

  DISALLOW_IMPLICIT_CONSTRUCTORS(Dex2Oat);
};

static void b13564922() {
#if defined(__linux__) && defined(__arm__)
  int major, minor;
  struct utsname uts;
  if (uname(&uts) != -1 &&
      sscanf(uts.release, "%d.%d", &major, &minor) == 2 &&
      ((major < 3) || ((major == 3) && (minor < 4)))) {
    // Kernels before 3.4 don't handle the ASLR well and we can run out of address
    // space (http://b/13564922). Work around the issue by inhibiting further mmap() randomization.
    int old_personality = personality(0xffffffff);
    if ((old_personality & ADDR_NO_RANDOMIZE) == 0) {
      int new_personality = personality(old_personality | ADDR_NO_RANDOMIZE);
      if (new_personality == -1) {
        LOG(WARNING) << "personality(. | ADDR_NO_RANDOMIZE) failed.";
      }
    }
  }
#endif
}

static int CompileImage(Dex2Oat& dex2oat) {
  dex2oat.Compile();

  if (!dex2oat.CreateOatFiles()) {
    dex2oat.EraseOatFiles();
    return EXIT_FAILURE;
  }

  // Close the image oat files. We always expect the output file by name, and it will be
  // re-opened from the unstripped name. Note: it's easier to *flush* and close...
  if (!dex2oat.FlushCloseOatFiles()) {
    return EXIT_FAILURE;
  }

  // Creates the boot.art and patches the oat files.
  if (!dex2oat.HandleImage()) {
    return EXIT_FAILURE;
  }

  // When given --host, finish early without stripping.
  if (dex2oat.IsHost()) {
    dex2oat.DumpTiming();
    return EXIT_SUCCESS;
  }

  // Copy stripped to unstripped location, if necessary.
  if (!dex2oat.CopyStrippedToUnstripped()) {
    return EXIT_FAILURE;
  }

  // FlushClose again, as stripping might have re-opened the oat files.
  if (!dex2oat.FlushCloseOatFiles()) {
    return EXIT_FAILURE;
  }

  dex2oat.DumpTiming();
  return EXIT_SUCCESS;
}

static int CompileApp(Dex2Oat& dex2oat) {
  dex2oat.Compile();

  if (!dex2oat.CreateOatFiles()) {
    dex2oat.EraseOatFiles();
    return EXIT_FAILURE;
  }

  // Do not close the oat files here. We might have gotten the output file by file descriptor,
  // which we would lose.

  // When given --host, finish early without stripping.
  if (dex2oat.IsHost()) {
    if (!dex2oat.FlushCloseOatFiles()) {
      return EXIT_FAILURE;
    }

    dex2oat.DumpTiming();
    return EXIT_SUCCESS;
  }

  // Copy stripped to unstripped location, if necessary. This will implicitly flush & close the
  // stripped versions. If this is given, we expect to be able to open writable files by name.
  if (!dex2oat.CopyStrippedToUnstripped()) {
    return EXIT_FAILURE;
  }

  // Flush and close the files.
  if (!dex2oat.FlushCloseOatFiles()) {
    return EXIT_FAILURE;
  }

  dex2oat.DumpTiming();
  return EXIT_SUCCESS;
}

static int dex2oat(int argc, char** argv) {
  b13564922();

  TimingLogger timings("compiler", false, false);

  Dex2Oat dex2oat(&timings);

  // Parse arguments. Argument mistakes will lead to exit(EXIT_FAILURE) in UsageError.
  dex2oat.ParseArgs(argc, argv);

  // Check early that the result of compilation can be written
  if (!dex2oat.OpenFile()) {
    return EXIT_FAILURE;
  }

  // Print the complete line when any of the following is true:
  //   1) Debug build
  //   2) Compiling an image
  //   3) Compiling with --host
  //   4) Compiling on the host (not a target build)
  // Otherwise, print a stripped command line.
  if (kIsDebugBuild || dex2oat.IsBootImage() || dex2oat.IsHost() || !kIsTargetBuild) {
    LOG(INFO) << CommandLine();
  } else {
    LOG(INFO) << StrippedCommandLine();
  }

  if (!dex2oat.Setup()) {
    dex2oat.EraseOatFiles();
    return EXIT_FAILURE;
  }

  bool result;
  if (dex2oat.IsImage()) {
    result = CompileImage(dex2oat);
  } else {
    result = CompileApp(dex2oat);
  }

  dex2oat.Shutdown();
  return result;
}
}  // namespace art

int main(int argc, char** argv) {
  int result = art::dex2oat(argc, argv);
  // Everything was done, do an explicit exit here to avoid running Runtime destructors that take
  // time (bug 10645725) unless we're a debug build or running on valgrind. Note: The Dex2Oat class
  // should not destruct the runtime in this case.
  if (!art::kIsDebugBuild && (RUNNING_ON_MEMORY_TOOL == 0)) {
    exit(result);
  }
  return result;
}