src/image_writer.h

/*
 * 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.
 */

#ifndef ART_SRC_IMAGE_WRITER_H_
#define ART_SRC_IMAGE_WRITER_H_

#include <stdint.h>

#include <cstddef>
#include <set>
#include <string>

#include "compiler/driver/compiler_driver.h"
#include "mem_map.h"
#include "oat_file.h"
#include "mirror/dex_cache.h"
#include "os.h"
#include "safe_map.h"
#include "gc/space/space.h"
#include "UniquePtr.h"

namespace art {

// Write a Space built during compilation for use during execution.
class ImageWriter {
 public:
  explicit ImageWriter(const CompilerDriver& compiler_driver)
      : compiler_driver_(compiler_driver), oat_file_(NULL), image_end_(0), image_begin_(NULL),
        oat_data_begin_(NULL), interpreter_to_interpreter_entry_offset_(0),
        interpreter_to_quick_entry_offset_(0), portable_resolution_trampoline_offset_(0),
        quick_resolution_trampoline_offset_(0) {}

  ~ImageWriter() {}

  bool Write(const std::string& image_filename,
             uintptr_t image_begin,
             const std::string& oat_filename,
             const std::string& oat_location)
      LOCKS_EXCLUDED(Locks::mutator_lock_);

  uintptr_t GetOatDataBegin() {
    return reinterpret_cast<uintptr_t>(oat_data_begin_);
  }

 private:
  bool AllocMemory();

  // we use the lock word to store the offset of the object in the image
  void AssignImageOffset(mirror::Object* object)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    DCHECK(object != NULL);
    SetImageOffset(object, image_end_);
    image_end_ += RoundUp(object->SizeOf(), 8);  // 64-bit alignment
    DCHECK_LT(image_end_, image_->Size());
  }

  void SetImageOffset(mirror::Object* object, size_t offset) {
    DCHECK(object != NULL);
    DCHECK_NE(offset, 0U);
    DCHECK(!IsImageOffsetAssigned(object));
    offsets_.Put(object, offset);
  }

  size_t IsImageOffsetAssigned(const mirror::Object* object) const {
    DCHECK(object != NULL);
    return offsets_.find(object) != offsets_.end();
  }

  size_t GetImageOffset(const mirror::Object* object) const {
    DCHECK(object != NULL);
    DCHECK(IsImageOffsetAssigned(object));
    return offsets_.find(object)->second;
  }

  mirror::Object* GetImageAddress(const mirror::Object* object) const {
    if (object == NULL) {
      return NULL;
    }
    return reinterpret_cast<mirror::Object*>(image_begin_ + GetImageOffset(object));
  }

  mirror::Object* GetLocalAddress(const mirror::Object* object) const {
    size_t offset = GetImageOffset(object);
    byte* dst = image_->Begin() + offset;
    return reinterpret_cast<mirror::Object*>(dst);
  }

  const byte* GetOatAddress(uint32_t offset) const {
#if !defined(ART_USE_PORTABLE_COMPILER)
    // With Quick, code is within the OatFile, as there are all in one
    // .o ELF object. However with Portable, the code is always in
    // different .o ELF objects.
    DCHECK_LT(offset, oat_file_->Size());
#endif
    if (offset == 0) {
      return NULL;
    }
    return oat_data_begin_ + offset;
  }

  // Returns true if the class was in the original requested image classes list.
  bool IsImageClass(const mirror::Class* klass) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  // Debug aid that list of requested image classes.
  void DumpImageClasses();

  // Preinitializes some otherwise lazy fields (such as Class name) to avoid runtime image dirtying.
  void ComputeLazyFieldsForImageClasses()
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  static bool ComputeLazyFieldsForClassesVisitor(mirror::Class* klass, void* arg)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  // Wire dex cache resolved strings to strings in the image to avoid runtime resolution.
  void ComputeEagerResolvedStrings();
  static void ComputeEagerResolvedStringsCallback(mirror::Object* obj, void* arg)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  // Remove unwanted classes from various roots.
  void PruneNonImageClasses() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  static bool NonImageClassesVisitor(mirror::Class* c, void* arg)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  // Verify unwanted classes removed.
  void CheckNonImageClassesRemoved();
  static void CheckNonImageClassesRemovedCallback(mirror::Object* obj, void* arg)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  // Lays out where the image objects will be at runtime.
  void CalculateNewObjectOffsets(size_t oat_loaded_size, size_t oat_data_offset)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  mirror::ObjectArray<mirror::Object>* CreateImageRoots() const
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  static void CalculateNewObjectOffsetsCallback(mirror::Object* obj, void* arg)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  // Creates the contiguous image in memory and adjusts pointers.
  void CopyAndFixupObjects();
  static void CopyAndFixupObjectsCallback(mirror::Object* obj, void* arg)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  void FixupClass(const mirror::Class* orig, mirror::Class* copy)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  void FixupMethod(const mirror::AbstractMethod* orig, mirror::AbstractMethod* copy)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  void FixupObject(const mirror::Object* orig, mirror::Object* copy)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  void FixupObjectArray(const mirror::ObjectArray<mirror::Object>* orig,
                        mirror::ObjectArray<mirror::Object>* copy)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  void FixupInstanceFields(const mirror::Object* orig, mirror::Object* copy)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  void FixupStaticFields(const mirror::Class* orig, mirror::Class* copy)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  void FixupFields(const mirror::Object* orig, mirror::Object* copy, uint32_t ref_offsets,
                   bool is_static)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  // Patches references in OatFile to expect runtime addresses.
  void PatchOatCodeAndMethods()
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
  void SetPatchLocation(const CompilerDriver::PatchInformation* patch, uint32_t value)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);


  const CompilerDriver& compiler_driver_;

  // Map of Object to where it will be at runtime.
  SafeMap<const mirror::Object*, size_t> offsets_;

  // oat file with code for this image
  OatFile* oat_file_;

  // Memory mapped for generating the image.
  UniquePtr<MemMap> image_;

  // Offset to the free space in image_.
  size_t image_end_;

  // Beginning target image address for the output image.
  byte* image_begin_;

  // Beginning target oat address for the pointers from the output image to its oat file.
  const byte* oat_data_begin_;

  // Offset from oat_data_begin_ to the stubs.
  uint32_t interpreter_to_interpreter_entry_offset_;
  uint32_t interpreter_to_quick_entry_offset_;
  uint32_t portable_resolution_trampoline_offset_;
  uint32_t quick_resolution_trampoline_offset_;

  // DexCaches seen while scanning for fixing up CodeAndDirectMethods
  typedef std::set<mirror::DexCache*> Set;
  Set dex_caches_;
};

}  // namespace art

#endif  // ART_SRC_IMAGE_WRITER_H_