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android / platform / art / refs/heads/main / . / runtime / runtime_image.cc
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/*
* Copyright (C) 2022 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 "runtime_image.h"
#include <lz4.h>
#include <unistd.h>
#include "android-base/file.h"
#include "android-base/stringprintf.h"
#include "android-base/strings.h"
#include "arch/instruction_set.h"
#include "arch/instruction_set_features.h"
#include "base/arena_allocator.h"
#include "base/arena_containers.h"
#include "base/bit_utils.h"
#include "base/file_utils.h"
#include "base/length_prefixed_array.h"
#include "base/scoped_flock.h"
#include "base/stl_util.h"
#include "base/systrace.h"
#include "base/unix_file/fd_file.h"
#include "base/utils.h"
#include "class_loader_context.h"
#include "class_loader_utils.h"
#include "class_root-inl.h"
#include "dex/class_accessor-inl.h"
#include "gc/space/image_space.h"
#include "mirror/object-inl.h"
#include "mirror/object-refvisitor-inl.h"
#include "mirror/object_array-alloc-inl.h"
#include "mirror/object_array-inl.h"
#include "mirror/object_array.h"
#include "mirror/string-inl.h"
#include "nterp_helpers.h"
#include "oat/image.h"
#include "oat/oat.h"
#include "profile/profile_compilation_info.h"
#include "scoped_thread_state_change-inl.h"
#include "vdex_file.h"
namespace art HIDDEN {
using android::base::StringPrintf;
/**
* The native data structures that we store in the image.
*/
enum class NativeRelocationKind {
kArtFieldArray,
kArtMethodArray,
kArtMethod,
kImTable,
// For dex cache arrays which can stay in memory even after startup. Those are
// dex cache arrays whose size is below a given threshold, defined by
// DexCache::ShouldAllocateFullArray.
kFullNativeDexCacheArray,
// For dex cache arrays which we will want to release after app startup.
kStartupNativeDexCacheArray,
};
/**
* Helper class to generate an app image at runtime.
*/
class RuntimeImageHelper {
public:
explicit RuntimeImageHelper(gc::Heap* heap) :
allocator_(Runtime::Current()->GetArenaPool()),
objects_(allocator_.Adapter()),
art_fields_(allocator_.Adapter()),
art_methods_(allocator_.Adapter()),
im_tables_(allocator_.Adapter()),
metadata_(allocator_.Adapter()),
dex_cache_arrays_(allocator_.Adapter()),
string_reference_offsets_(allocator_.Adapter()),
sections_(ImageHeader::kSectionCount, allocator_.Adapter()),
object_offsets_(allocator_.Adapter()),
classes_(allocator_.Adapter()),
array_classes_(allocator_.Adapter()),
dex_caches_(allocator_.Adapter()),
class_hashes_(allocator_.Adapter()),
native_relocations_(allocator_.Adapter()),
boot_image_begin_(heap->GetBootImagesStartAddress()),
boot_image_size_(heap->GetBootImagesSize()),
image_begin_(boot_image_begin_ + boot_image_size_),
// Note: image relocation considers the image header in the bitmap.
object_section_size_(sizeof(ImageHeader)),
intern_table_(InternStringHash(this), InternStringEquals(this)),
class_table_(ClassDescriptorHash(this), ClassDescriptorEquals()) {}
bool Generate(std::string* error_msg) {
if (!WriteObjects(error_msg)) {
return false;
}
// Generate the sections information stored in the header.
CreateImageSections();
// Now that all sections have been created and we know their offset and
// size, relocate native pointers inside classes and ImTables.
RelocateNativePointers();
// Generate the bitmap section, stored kElfSegmentAlignment-aligned after the sections data and
// of size `object_section_size_` rounded up to kCardSize to match the bitmap size expected by
// Loader::Init at art::gc::space::ImageSpace.
size_t sections_end = sections_[ImageHeader::kSectionMetadata].End();
image_bitmap_ = gc::accounting::ContinuousSpaceBitmap::Create(
"image bitmap",
reinterpret_cast<uint8_t*>(image_begin_),
RoundUp(object_section_size_, gc::accounting::CardTable::kCardSize));
for (uint32_t offset : object_offsets_) {
DCHECK(IsAligned<kObjectAlignment>(image_begin_ + sizeof(ImageHeader) + offset));
image_bitmap_.Set(
reinterpret_cast<mirror::Object*>(image_begin_ + sizeof(ImageHeader) + offset));
}
const size_t bitmap_bytes = image_bitmap_.Size();
auto* bitmap_section = &sections_[ImageHeader::kSectionImageBitmap];
// The offset of the bitmap section should be aligned to kElfSegmentAlignment to enable mapping
// the section from file to memory. However the section size doesn't have to be rounded up as
// it is located at the end of the file. When mapping file contents to memory, if the last page
// of the mapping is only partially filled with data, the rest will be zero-filled.
*bitmap_section = ImageSection(RoundUp(sections_end, kElfSegmentAlignment), bitmap_bytes);
// Compute boot image checksum and boot image components, to be stored in
// the header.
gc::Heap* const heap = Runtime::Current()->GetHeap();
uint32_t boot_image_components = 0u;
uint32_t boot_image_checksums = 0u;
const std::vector<gc::space::ImageSpace*>& image_spaces = heap->GetBootImageSpaces();
for (size_t i = 0u, size = image_spaces.size(); i != size; ) {
const ImageHeader& header = image_spaces[i]->GetImageHeader();
boot_image_components += header.GetComponentCount();
boot_image_checksums ^= header.GetImageChecksum();
DCHECK_LE(header.GetImageSpaceCount(), size - i);
i += header.GetImageSpaceCount();
}
header_ = ImageHeader(
/* image_reservation_size= */ RoundUp(sections_end, kElfSegmentAlignment),
/* component_count= */ 1,
image_begin_,
sections_end,
sections_.data(),
/* image_roots= */ image_begin_ + sizeof(ImageHeader),
/* oat_checksum= */ 0,
/* oat_file_begin= */ 0,
/* oat_data_begin= */ 0,
/* oat_data_end= */ 0,
/* oat_file_end= */ 0,
heap->GetBootImagesStartAddress(),
heap->GetBootImagesSize(),
boot_image_components,
boot_image_checksums,
kRuntimePointerSize);
// Data size includes everything except the bitmap and the header.
header_.data_size_ = sections_end - sizeof(ImageHeader);
// Write image methods - needs to happen after creation of the header.
WriteImageMethods();
return true;
}
void FillData(std::vector<uint8_t>& data) {
// Note we don't put the header, we only have it reserved in `data` as
// Image::WriteData expects the object section to contain the image header.
auto compute_dest = [&](const ImageSection& section) {
return data.data() + section.Offset();
};
auto objects_section = header_.GetImageSection(ImageHeader::kSectionObjects);
memcpy(compute_dest(objects_section) + sizeof(ImageHeader), objects_.data(), objects_.size());
auto fields_section = header_.GetImageSection(ImageHeader::kSectionArtFields);
memcpy(compute_dest(fields_section), art_fields_.data(), fields_section.Size());
auto methods_section = header_.GetImageSection(ImageHeader::kSectionArtMethods);
memcpy(compute_dest(methods_section), art_methods_.data(), methods_section.Size());
auto im_tables_section = header_.GetImageSection(ImageHeader::kSectionImTables);
memcpy(compute_dest(im_tables_section), im_tables_.data(), im_tables_section.Size());
auto intern_section = header_.GetImageSection(ImageHeader::kSectionInternedStrings);
intern_table_.WriteToMemory(compute_dest(intern_section));
auto class_table_section = header_.GetImageSection(ImageHeader::kSectionClassTable);
class_table_.WriteToMemory(compute_dest(class_table_section));
auto string_offsets_section =
header_.GetImageSection(ImageHeader::kSectionStringReferenceOffsets);
memcpy(compute_dest(string_offsets_section),
string_reference_offsets_.data(),
string_offsets_section.Size());
auto dex_cache_section = header_.GetImageSection(ImageHeader::kSectionDexCacheArrays);
memcpy(compute_dest(dex_cache_section), dex_cache_arrays_.data(), dex_cache_section.Size());
auto metadata_section = header_.GetImageSection(ImageHeader::kSectionMetadata);
memcpy(compute_dest(metadata_section), metadata_.data(), metadata_section.Size());
DCHECK_EQ(metadata_section.Offset() + metadata_section.Size(), data.size());
}
ImageHeader* GetHeader() {
return &header_;
}
const gc::accounting::ContinuousSpaceBitmap& GetImageBitmap() const {
return image_bitmap_;
}
const std::string& GetDexLocation() const {
return dex_location_;
}
private:
bool IsInBootImage(const void* obj) const {
return reinterpret_cast<uintptr_t>(obj) - boot_image_begin_ < boot_image_size_;
}
// Returns the image contents for `cls`. If `cls` is in the boot image, the
// method just returns it.
mirror::Class* GetClassContent(ObjPtr<mirror::Class> cls) REQUIRES_SHARED(Locks::mutator_lock_) {
if (cls == nullptr || IsInBootImage(cls.Ptr())) {
return cls.Ptr();
}
const dex::ClassDef* class_def = cls->GetClassDef();
DCHECK(class_def != nullptr) << cls->PrettyClass();
auto it = classes_.find(class_def);
DCHECK(it != classes_.end()) << cls->PrettyClass();
mirror::Class* result = reinterpret_cast<mirror::Class*>(objects_.data() + it->second);
DCHECK(result->GetClass()->IsClass());
return result;
}
// Returns a pointer that can be stored in `objects_`:
// - The pointer itself for boot image objects,
// - The offset in the image for all other objects.
template <typename T> T* GetOrComputeImageAddress(ObjPtr<T> object)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (object == nullptr || IsInBootImage(object.Ptr())) {
DCHECK(object == nullptr || Runtime::Current()->GetHeap()->ObjectIsInBootImageSpace(object));
return object.Ptr();
}
if (object->IsClassLoader()) {
// DexCache and Class point to class loaders. For runtime-generated app
// images, we don't encode the class loader. It will be set when the
// runtime is loading the image.
return nullptr;
}
if (object->GetClass() == GetClassRoot<mirror::ClassExt>()) {
// No need to encode `ClassExt`. If needed, it will be reconstructed at
// runtime.
return nullptr;
}
uint32_t offset = 0u;
if (object->IsClass()) {
offset = CopyClass(object->AsClass());
} else if (object->IsDexCache()) {
offset = CopyDexCache(object->AsDexCache());
} else {
offset = CopyObject(object);
}
return reinterpret_cast<T*>(image_begin_ + sizeof(ImageHeader) + offset);
}
void CreateImageSections() {
sections_[ImageHeader::kSectionObjects] = ImageSection(0u, object_section_size_);
sections_[ImageHeader::kSectionArtFields] =
ImageSection(sections_[ImageHeader::kSectionObjects].End(), art_fields_.size());
// Round up to the alignment for ArtMethod.
static_assert(IsAligned<sizeof(void*)>(ArtMethod::Size(kRuntimePointerSize)));
size_t cur_pos = RoundUp(sections_[ImageHeader::kSectionArtFields].End(), sizeof(void*));
sections_[ImageHeader::kSectionArtMethods] = ImageSection(cur_pos, art_methods_.size());
// Round up to the alignment for ImTables.
cur_pos = RoundUp(sections_[ImageHeader::kSectionArtMethods].End(), sizeof(void*));
sections_[ImageHeader::kSectionImTables] = ImageSection(cur_pos, im_tables_.size());
// Round up to the alignment for conflict tables.
cur_pos = RoundUp(sections_[ImageHeader::kSectionImTables].End(), sizeof(void*));
sections_[ImageHeader::kSectionIMTConflictTables] = ImageSection(cur_pos, 0u);
sections_[ImageHeader::kSectionRuntimeMethods] =
ImageSection(sections_[ImageHeader::kSectionIMTConflictTables].End(), 0u);
// Round up to the alignment the string table expects. See HashSet::WriteToMemory.
cur_pos = RoundUp(sections_[ImageHeader::kSectionRuntimeMethods].End(), sizeof(uint64_t));
size_t intern_table_bytes = intern_table_.WriteToMemory(nullptr);
sections_[ImageHeader::kSectionInternedStrings] = ImageSection(cur_pos, intern_table_bytes);
// Obtain the new position and round it up to the appropriate alignment.
cur_pos = RoundUp(sections_[ImageHeader::kSectionInternedStrings].End(), sizeof(uint64_t));
size_t class_table_bytes = class_table_.WriteToMemory(nullptr);
sections_[ImageHeader::kSectionClassTable] = ImageSection(cur_pos, class_table_bytes);
// Round up to the alignment of the offsets we are going to store.
cur_pos = RoundUp(sections_[ImageHeader::kSectionClassTable].End(), sizeof(uint32_t));
sections_[ImageHeader::kSectionStringReferenceOffsets] = ImageSection(
cur_pos, string_reference_offsets_.size() * sizeof(string_reference_offsets_[0]));
// Round up to the alignment dex caches arrays expects.
cur_pos =
RoundUp(sections_[ImageHeader::kSectionStringReferenceOffsets].End(), sizeof(void*));
sections_[ImageHeader::kSectionDexCacheArrays] =
ImageSection(cur_pos, dex_cache_arrays_.size());
// Round up to the alignment expected for the metadata, which holds dex
// cache arrays.
cur_pos = RoundUp(sections_[ImageHeader::kSectionDexCacheArrays].End(), sizeof(void*));
sections_[ImageHeader::kSectionMetadata] = ImageSection(cur_pos, metadata_.size());
}
// Returns the copied mirror Object if in the image, or the object directly if
// in the boot image. For the copy, this is really its content, it should not
// be returned as an `ObjPtr` (as it's not a GC object), nor stored anywhere.
template<typename T> T* FromImageOffsetToRuntimeContent(uint32_t offset) {
if (offset == 0u || IsInBootImage(reinterpret_cast<const void*>(offset))) {
return reinterpret_cast<T*>(offset);
}
uint32_t vector_data_offset = FromImageOffsetToVectorOffset(offset);
return reinterpret_cast<T*>(objects_.data() + vector_data_offset);
}
uint32_t FromImageOffsetToVectorOffset(uint32_t offset) const {
DCHECK(!IsInBootImage(reinterpret_cast<const void*>(offset)));
return offset - sizeof(ImageHeader) - image_begin_;
}
class InternStringHash {
public:
explicit InternStringHash(RuntimeImageHelper* helper) : helper_(helper) {}
// NO_THREAD_SAFETY_ANALYSIS as these helpers get passed to `HashSet`.
size_t operator()(mirror::String* str) const NO_THREAD_SAFETY_ANALYSIS {
int32_t hash = str->GetStoredHashCode();
DCHECK_EQ(hash, str->ComputeHashCode());
// An additional cast to prevent undesired sign extension.
return static_cast<uint32_t>(hash);
}
size_t operator()(uint32_t entry) const NO_THREAD_SAFETY_ANALYSIS {
return (*this)(helper_->FromImageOffsetToRuntimeContent<mirror::String>(entry));
}
private:
RuntimeImageHelper* helper_;
};
class InternStringEquals {
public:
explicit InternStringEquals(RuntimeImageHelper* helper) : helper_(helper) {}
// NO_THREAD_SAFETY_ANALYSIS as these helpers get passed to `HashSet`.
bool operator()(uint32_t entry, mirror::String* other) const NO_THREAD_SAFETY_ANALYSIS {
if (kIsDebugBuild) {
Locks::mutator_lock_->AssertSharedHeld(Thread::Current());
}
return other->Equals(helper_->FromImageOffsetToRuntimeContent<mirror::String>(entry));
}
bool operator()(uint32_t entry, uint32_t other) const NO_THREAD_SAFETY_ANALYSIS {
return (*this)(entry, helper_->FromImageOffsetToRuntimeContent<mirror::String>(other));
}
private:
RuntimeImageHelper* helper_;
};
using InternTableSet =
HashSet<uint32_t, DefaultEmptyFn<uint32_t>, InternStringHash, InternStringEquals>;
class ClassDescriptorHash {
public:
explicit ClassDescriptorHash(RuntimeImageHelper* helper) : helper_(helper) {}
uint32_t operator()(const ClassTable::TableSlot& slot) const NO_THREAD_SAFETY_ANALYSIS {
uint32_t ptr = slot.NonHashData();
if (helper_->IsInBootImage(reinterpret_cast32<const void*>(ptr))) {
return reinterpret_cast32<mirror::Class*>(ptr)->DescriptorHash();
}
return helper_->class_hashes_.Get(helper_->FromImageOffsetToVectorOffset(ptr));
}
private:
RuntimeImageHelper* helper_;
};
class ClassDescriptorEquals {
public:
ClassDescriptorEquals() {}
bool operator()(const ClassTable::TableSlot& a, const ClassTable::TableSlot& b)
const NO_THREAD_SAFETY_ANALYSIS {
// No need to fetch the descriptor: we know the classes we are inserting
// in the ClassTable are unique.
return a.Data() == b.Data();
}
};
using ClassTableSet = HashSet<ClassTable::TableSlot,
ClassTable::TableSlotEmptyFn,
ClassDescriptorHash,
ClassDescriptorEquals>;
// Helper class to collect classes that we will generate in the image.
class ClassTableVisitor {
public:
ClassTableVisitor(Handle<mirror::ClassLoader> loader, VariableSizedHandleScope& handles)
: loader_(loader), handles_(handles) {}
bool operator()(ObjPtr<mirror::Class> klass) REQUIRES_SHARED(Locks::mutator_lock_) {
// Record app classes and boot classpath classes: app classes will be
// generated in the image and put in the class table, boot classpath
// classes will be put in the class table.
ObjPtr<mirror::ClassLoader> class_loader = klass->GetClassLoader();
if (klass->IsResolved() && (class_loader == loader_.Get() || class_loader == nullptr)) {
handles_.NewHandle(klass);
}
return true;
}
private:
Handle<mirror::ClassLoader> loader_;
VariableSizedHandleScope& handles_;
};
// Helper class visitor to filter out classes we cannot emit.
class PruneVisitor {
public:
PruneVisitor(Thread* self,
RuntimeImageHelper* helper,
const ArenaSet<const DexFile*>& dex_files,
ArenaVector<Handle<mirror::Class>>& classes,
ArenaAllocator& allocator)
: self_(self),
helper_(helper),
dex_files_(dex_files),
visited_(allocator.Adapter()),
classes_to_write_(classes) {}
bool CanEmitHelper(Handle<mirror::Class> cls) REQUIRES_SHARED(Locks::mutator_lock_) {
// If the class comes from a dex file which is not part of the primary
// APK, don't encode it.
if (!ContainsElement(dex_files_, &cls->GetDexFile())) {
return false;
}
// Ensure pointers to classes in `cls` can also be emitted.
StackHandleScope<1> hs(self_);
MutableHandle<mirror::Class> other_class = hs.NewHandle(cls->GetSuperClass());
if (!CanEmit(other_class)) {
return false;
}
other_class.Assign(cls->GetComponentType());
if (!CanEmit(other_class)) {
return false;
}
for (size_t i = 0, num_interfaces = cls->NumDirectInterfaces(); i < num_interfaces; ++i) {
other_class.Assign(cls->GetDirectInterface(i));
DCHECK(other_class != nullptr);
if (!CanEmit(other_class)) {
return false;
}
}
return true;
}
bool CanEmit(Handle<mirror::Class> cls) REQUIRES_SHARED(Locks::mutator_lock_) {
if (cls == nullptr) {
return true;
}
DCHECK(cls->IsResolved());
// Only emit classes that are resolved and not erroneous.
if (cls->IsErroneous()) {
return false;
}
// Proxy classes are generated at runtime, so don't emit them.
if (cls->IsProxyClass()) {
return false;
}
// Classes in the boot image can be trivially encoded directly.
if (helper_->IsInBootImage(cls.Get())) {
return true;
}
if (cls->IsBootStrapClassLoaded()) {
// We cannot encode classes that are part of the boot classpath.
return false;
}
DCHECK(!cls->IsPrimitive());
if (cls->IsArrayClass()) {
if (cls->IsBootStrapClassLoaded()) {
// For boot classpath arrays, we can only emit them if they are
// in the boot image already.
return helper_->IsInBootImage(cls.Get());
}
ObjPtr<mirror::Class> temp = cls.Get();
while ((temp = temp->GetComponentType())->IsArrayClass()) {}
StackHandleScope<1> hs(self_);
Handle<mirror::Class> other_class = hs.NewHandle(temp);
return CanEmit(other_class);
}
const dex::ClassDef* class_def = cls->GetClassDef();
DCHECK_NE(class_def, nullptr);
auto existing = visited_.find(class_def);
if (existing != visited_.end()) {
// Already processed;
return existing->second == VisitState::kCanEmit;
}
visited_.Put(class_def, VisitState::kVisiting);
if (CanEmitHelper(cls)) {
visited_.Overwrite(class_def, VisitState::kCanEmit);
return true;
} else {
visited_.Overwrite(class_def, VisitState::kCannotEmit);
return false;
}
}
void Visit(Handle<mirror::Object> obj) REQUIRES_SHARED(Locks::mutator_lock_) {
MutableHandle<mirror::Class> cls(obj.GetReference());
if (CanEmit(cls)) {
if (cls->IsBootStrapClassLoaded()) {
DCHECK(helper_->IsInBootImage(cls.Get()));
// Insert the bootclasspath class in the class table.
uint32_t hash = cls->DescriptorHash();
helper_->class_table_.InsertWithHash(ClassTable::TableSlot(cls.Get(), hash), hash);
} else {
classes_to_write_.push_back(cls);
}
}
}
private:
enum class VisitState {
kVisiting,
kCanEmit,
kCannotEmit,
};
Thread* const self_;
RuntimeImageHelper* const helper_;
const ArenaSet<const DexFile*>& dex_files_;
ArenaSafeMap<const dex::ClassDef*, VisitState> visited_;
ArenaVector<Handle<mirror::Class>>& classes_to_write_;
};
void EmitClasses(Thread* self, Handle<mirror::ObjectArray<mirror::Object>> dex_cache_array)
REQUIRES_SHARED(Locks::mutator_lock_) {
ScopedTrace trace("Emit strings and classes");
ArenaSet<const DexFile*> dex_files(allocator_.Adapter());
for (int32_t i = 0; i < dex_cache_array->GetLength(); ++i) {
dex_files.insert(dex_cache_array->Get(i)->AsDexCache()->GetDexFile());
}
StackHandleScope<1> hs(self);
Handle<mirror::ClassLoader> loader = hs.NewHandle(
dex_cache_array->Get(0)->AsDexCache()->GetClassLoader());
ClassTable* const class_table = loader->GetClassTable();
if (class_table == nullptr) {
return;
}
VariableSizedHandleScope handles(self);
{
ClassTableVisitor class_table_visitor(loader, handles);
class_table->Visit(class_table_visitor);
}
ArenaVector<Handle<mirror::Class>> classes_to_write(allocator_.Adapter());
classes_to_write.reserve(class_table->Size());
{
PruneVisitor prune_visitor(self, this, dex_files, classes_to_write, allocator_);
handles.VisitHandles(prune_visitor);
}
for (Handle<mirror::Class> cls : classes_to_write) {
{
ScopedAssertNoThreadSuspension sants("Writing class");
CopyClass(cls.Get());
}
self->AllowThreadSuspension();
}
// Relocate the type array entries. We do this now before creating image
// sections because we may add new boot image classes into our
// `class_table`_.
for (auto entry : dex_caches_) {
const DexFile& dex_file = *entry.first;
mirror::DexCache* cache = reinterpret_cast<mirror::DexCache*>(&objects_[entry.second]);
mirror::GcRootArray<mirror::Class>* old_types_array = cache->GetResolvedTypesArray();
if (HasNativeRelocation(old_types_array)) {
auto reloc_it = native_relocations_.find(old_types_array);
DCHECK(reloc_it != native_relocations_.end());
ArenaVector<uint8_t>& data =
(reloc_it->second.first == NativeRelocationKind::kFullNativeDexCacheArray)
? dex_cache_arrays_ : metadata_;
mirror::GcRootArray<mirror::Class>* content_array =
reinterpret_cast<mirror::GcRootArray<mirror::Class>*>(
data.data() + reloc_it->second.second);
for (uint32_t i = 0; i < dex_file.NumTypeIds(); ++i) {
ObjPtr<mirror::Class> cls = old_types_array->Get(i);
if (cls == nullptr) {
content_array->Set(i, nullptr);
} else if (IsInBootImage(cls.Ptr())) {
if (!cls->IsPrimitive()) {
// The dex cache is concurrently updated by the app. If the class
// collection logic in `PruneVisitor` did not see this class, insert it now.
// Note that application class tables do not contain primitive
// classes.
uint32_t hash = cls->DescriptorHash();
class_table_.InsertWithHash(ClassTable::TableSlot(cls.Ptr(), hash), hash);
}
content_array->Set(i, cls.Ptr());
} else if (cls->IsArrayClass()) {
std::string class_name;
cls->GetDescriptor(&class_name);
auto class_it = array_classes_.find(class_name);
if (class_it == array_classes_.end()) {
content_array->Set(i, nullptr);
} else {
mirror::Class* ptr = reinterpret_cast<mirror::Class*>(
image_begin_ + sizeof(ImageHeader) + class_it->second);
content_array->Set(i, ptr);
}
} else {
DCHECK(!cls->IsPrimitive());
DCHECK(!cls->IsProxyClass());
const dex::ClassDef* class_def = cls->GetClassDef();
DCHECK_NE(class_def, nullptr);
auto class_it = classes_.find(class_def);
if (class_it == classes_.end()) {
content_array->Set(i, nullptr);
} else {
mirror::Class* ptr = reinterpret_cast<mirror::Class*>(
image_begin_ + sizeof(ImageHeader) + class_it->second);
content_array->Set(i, ptr);
}
}
}
}
}
}
// Helper visitor returning the location of a native pointer in the image.
class NativePointerVisitor {
public:
explicit NativePointerVisitor(RuntimeImageHelper* helper) : helper_(helper) {}
template <typename T>
T* operator()(T* ptr, [[maybe_unused]] void** dest_addr) const {
return helper_->NativeLocationInImage(ptr, /* must_have_relocation= */ true);
}
template <typename T> T* operator()(T* ptr, bool must_have_relocation = true) const {
return helper_->NativeLocationInImage(ptr, must_have_relocation);
}
private:
RuntimeImageHelper* helper_;
};
template <typename T> T* NativeLocationInImage(T* ptr, bool must_have_relocation) const {
if (ptr == nullptr || IsInBootImage(ptr)) {
return ptr;
}
auto it = native_relocations_.find(ptr);
if (it == native_relocations_.end()) {
DCHECK(!must_have_relocation);
return nullptr;
}
switch (it->second.first) {
case NativeRelocationKind::kArtMethod:
case NativeRelocationKind::kArtMethodArray: {
uint32_t offset = sections_[ImageHeader::kSectionArtMethods].Offset();
return reinterpret_cast<T*>(image_begin_ + offset + it->second.second);
}
case NativeRelocationKind::kArtFieldArray: {
uint32_t offset = sections_[ImageHeader::kSectionArtFields].Offset();
return reinterpret_cast<T*>(image_begin_ + offset + it->second.second);
}
case NativeRelocationKind::kImTable: {
uint32_t offset = sections_[ImageHeader::kSectionImTables].Offset();
return reinterpret_cast<T*>(image_begin_ + offset + it->second.second);
}
case NativeRelocationKind::kStartupNativeDexCacheArray: {
uint32_t offset = sections_[ImageHeader::kSectionMetadata].Offset();
return reinterpret_cast<T*>(image_begin_ + offset + it->second.second);
}
case NativeRelocationKind::kFullNativeDexCacheArray: {
uint32_t offset = sections_[ImageHeader::kSectionDexCacheArrays].Offset();
return reinterpret_cast<T*>(image_begin_ + offset + it->second.second);
}
}
}
template <typename Visitor>
void RelocateMethodPointerArrays(mirror::Class* klass, const Visitor& visitor)
REQUIRES_SHARED(Locks::mutator_lock_) {
// A bit of magic here: we cast contents from our buffer to mirror::Class,
// and do pointer comparison between 1) these classes, and 2) boot image objects.
// Both kinds do not move.
// See if we need to fixup the vtable field.
mirror::Class* super = FromImageOffsetToRuntimeContent<mirror::Class>(
reinterpret_cast32<uint32_t>(
klass->GetSuperClass<kVerifyNone, kWithoutReadBarrier>().Ptr()));
DCHECK(super != nullptr) << "j.l.Object should never be in an app runtime image";
mirror::PointerArray* vtable = FromImageOffsetToRuntimeContent<mirror::PointerArray>(
reinterpret_cast32<uint32_t>(klass->GetVTable<kVerifyNone, kWithoutReadBarrier>().Ptr()));
mirror::PointerArray* super_vtable = FromImageOffsetToRuntimeContent<mirror::PointerArray>(
reinterpret_cast32<uint32_t>(super->GetVTable<kVerifyNone, kWithoutReadBarrier>().Ptr()));
if (vtable != nullptr && vtable != super_vtable) {
DCHECK(!IsInBootImage(vtable));
vtable->Fixup(vtable, kRuntimePointerSize, visitor);
}
// See if we need to fixup entries in the IfTable.
mirror::IfTable* iftable = FromImageOffsetToRuntimeContent<mirror::IfTable>(
reinterpret_cast32<uint32_t>(
klass->GetIfTable<kVerifyNone, kWithoutReadBarrier>().Ptr()));
mirror::IfTable* super_iftable = FromImageOffsetToRuntimeContent<mirror::IfTable>(
reinterpret_cast32<uint32_t>(
super->GetIfTable<kVerifyNone, kWithoutReadBarrier>().Ptr()));
int32_t iftable_count = iftable->Count();
int32_t super_iftable_count = super_iftable->Count();
for (int32_t i = 0; i < iftable_count; ++i) {
mirror::PointerArray* methods = FromImageOffsetToRuntimeContent<mirror::PointerArray>(
reinterpret_cast32<uint32_t>(
iftable->GetMethodArrayOrNull<kVerifyNone, kWithoutReadBarrier>(i).Ptr()));
mirror::PointerArray* super_methods = (i < super_iftable_count)
? FromImageOffsetToRuntimeContent<mirror::PointerArray>(
reinterpret_cast32<uint32_t>(
super_iftable->GetMethodArrayOrNull<kVerifyNone, kWithoutReadBarrier>(i).Ptr()))
: nullptr;
if (methods != super_methods) {
DCHECK(!IsInBootImage(methods));
methods->Fixup(methods, kRuntimePointerSize, visitor);
}
}
}
template <typename Visitor, typename T>
void RelocateNativeDexCacheArray(mirror::NativeArray<T>* old_method_array,
uint32_t num_ids,
const Visitor& visitor)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (old_method_array == nullptr) {
return;
}
auto it = native_relocations_.find(old_method_array);
DCHECK(it != native_relocations_.end());
ArenaVector<uint8_t>& data =
(it->second.first == NativeRelocationKind::kFullNativeDexCacheArray)
? dex_cache_arrays_ : metadata_;
mirror::NativeArray<T>* content_array =
reinterpret_cast<mirror::NativeArray<T>*>(data.data() + it->second.second);
for (uint32_t i = 0; i < num_ids; ++i) {
// We may not have relocations for some entries, in which case we'll
// just store null.
content_array->Set(i, visitor(content_array->Get(i), /* must_have_relocation= */ false));
}
}
template <typename Visitor>
void RelocateDexCacheArrays(mirror::DexCache* cache,
const DexFile& dex_file,
const Visitor& visitor)
REQUIRES_SHARED(Locks::mutator_lock_) {
mirror::NativeArray<ArtMethod>* old_method_array = cache->GetResolvedMethodsArray();
cache->SetResolvedMethodsArray(visitor(old_method_array));
RelocateNativeDexCacheArray(old_method_array, dex_file.NumMethodIds(), visitor);
mirror::NativeArray<ArtField>* old_field_array = cache->GetResolvedFieldsArray();
cache->SetResolvedFieldsArray(visitor(old_field_array));
RelocateNativeDexCacheArray(old_field_array, dex_file.NumFieldIds(), visitor);
mirror::GcRootArray<mirror::String>* old_strings_array = cache->GetStringsArray();
cache->SetStringsArray(visitor(old_strings_array));
mirror::GcRootArray<mirror::Class>* old_types_array = cache->GetResolvedTypesArray();
cache->SetResolvedTypesArray(visitor(old_types_array));
}
void RelocateNativePointers() {
ScopedTrace relocate_native_pointers("Relocate native pointers");
ScopedObjectAccess soa(Thread::Current());
NativePointerVisitor visitor(this);
for (auto&& entry : classes_) {
mirror::Class* cls = reinterpret_cast<mirror::Class*>(&objects_[entry.second]);
cls->FixupNativePointers(cls, kRuntimePointerSize, visitor);
RelocateMethodPointerArrays(cls, visitor);
}
for (auto&& entry : array_classes_) {
mirror::Class* cls = reinterpret_cast<mirror::Class*>(&objects_[entry.second]);
cls->FixupNativePointers(cls, kRuntimePointerSize, visitor);
RelocateMethodPointerArrays(cls, visitor);
}
for (auto&& entry : native_relocations_) {
if (entry.second.first == NativeRelocationKind::kImTable) {
ImTable* im_table = reinterpret_cast<ImTable*>(im_tables_.data() + entry.second.second);
RelocateImTable(im_table, visitor);
}
}
for (auto&& entry : dex_caches_) {
mirror::DexCache* cache = reinterpret_cast<mirror::DexCache*>(&objects_[entry.second]);
RelocateDexCacheArrays(cache, *entry.first, visitor);
}
}
void RelocateImTable(ImTable* im_table, const NativePointerVisitor& visitor) {
for (size_t i = 0; i < ImTable::kSize; ++i) {
ArtMethod* method = im_table->Get(i, kRuntimePointerSize);
ArtMethod* new_method = nullptr;
if (method->IsRuntimeMethod() && !IsInBootImage(method)) {
// New IMT conflict method: just use the boot image version.
// TODO: Consider copying the new IMT conflict method.
new_method = Runtime::Current()->GetImtConflictMethod();
DCHECK(IsInBootImage(new_method));
} else {
new_method = visitor(method);
}
if (method != new_method) {
im_table->Set(i, new_method, kRuntimePointerSize);
}
}
}
void CopyFieldArrays(ObjPtr<mirror::Class> cls, uint32_t class_image_address)
REQUIRES_SHARED(Locks::mutator_lock_) {
LengthPrefixedArray<ArtField>* fields[] = {
cls->GetSFieldsPtr(), cls->GetIFieldsPtr(),
};
for (LengthPrefixedArray<ArtField>* cur_fields : fields) {
if (cur_fields != nullptr) {
// Copy the array.
size_t number_of_fields = cur_fields->size();
size_t size = LengthPrefixedArray<ArtField>::ComputeSize(number_of_fields);
size_t offset = art_fields_.size();
art_fields_.resize(offset + size);
auto* dest_array =
reinterpret_cast<LengthPrefixedArray<ArtField>*>(art_fields_.data() + offset);
memcpy(dest_array, cur_fields, size);
native_relocations_.Put(cur_fields,
std::make_pair(NativeRelocationKind::kArtFieldArray, offset));
// Update the class pointer of individual fields.
for (size_t i = 0; i != number_of_fields; ++i) {
dest_array->At(i).GetDeclaringClassAddressWithoutBarrier()->Assign(
reinterpret_cast<mirror::Class*>(class_image_address));
}
}
}
}
void CopyMethodArrays(ObjPtr<mirror::Class> cls,
uint32_t class_image_address,
bool is_class_initialized)
REQUIRES_SHARED(Locks::mutator_lock_) {
size_t number_of_methods = cls->NumMethods();
if (number_of_methods == 0) {
return;
}
size_t size = LengthPrefixedArray<ArtMethod>::ComputeSize(number_of_methods);
size_t offset = art_methods_.size();
art_methods_.resize(offset + size);
auto* dest_array =
reinterpret_cast<LengthPrefixedArray<ArtMethod>*>(art_methods_.data() + offset);
memcpy(dest_array, cls->GetMethodsPtr(), size);
native_relocations_.Put(cls->GetMethodsPtr(),
std::make_pair(NativeRelocationKind::kArtMethodArray, offset));
for (size_t i = 0; i != number_of_methods; ++i) {
ArtMethod* method = &cls->GetMethodsPtr()->At(i);
ArtMethod* copy = &dest_array->At(i);
// Update the class pointer.
ObjPtr<mirror::Class> declaring_class = method->GetDeclaringClass();
if (declaring_class == cls) {
copy->GetDeclaringClassAddressWithoutBarrier()->Assign(
reinterpret_cast<mirror::Class*>(class_image_address));
} else {
DCHECK(method->IsCopied());
if (!IsInBootImage(declaring_class.Ptr())) {
DCHECK(classes_.find(declaring_class->GetClassDef()) != classes_.end());
copy->GetDeclaringClassAddressWithoutBarrier()->Assign(
reinterpret_cast<mirror::Class*>(
image_begin_ +
sizeof(ImageHeader) +
classes_.Get(declaring_class->GetClassDef())));
}
}
// Record the native relocation of the method.
uintptr_t copy_offset =
reinterpret_cast<uintptr_t>(copy) - reinterpret_cast<uintptr_t>(art_methods_.data());
native_relocations_.Put(method,
std::make_pair(NativeRelocationKind::kArtMethod, copy_offset));
// Ignore the single-implementation info for abstract method.
if (method->IsAbstract()) {
copy->SetHasSingleImplementation(false);
copy->SetSingleImplementation(nullptr, kRuntimePointerSize);
}
// Set the entrypoint and data pointer of the method.
StubType stub;
if (method->IsNative()) {
stub = StubType::kQuickGenericJNITrampoline;
} else if (!cls->IsVerified()) {
stub = StubType::kQuickToInterpreterBridge;
} else if (!is_class_initialized && method->NeedsClinitCheckBeforeCall()) {
stub = StubType::kQuickResolutionTrampoline;
} else if (interpreter::IsNterpSupported() && CanMethodUseNterp(method)) {
stub = StubType::kNterpTrampoline;
} else {
stub = StubType::kQuickToInterpreterBridge;
}
const std::vector<gc::space::ImageSpace*>& image_spaces =
Runtime::Current()->GetHeap()->GetBootImageSpaces();
DCHECK(!image_spaces.empty());
const OatFile* oat_file = image_spaces[0]->GetOatFile();
DCHECK(oat_file != nullptr);
const OatHeader& header = oat_file->GetOatHeader();
const void* entrypoint = header.GetOatAddress(stub);
if (method->IsNative() && (is_class_initialized || !method->NeedsClinitCheckBeforeCall())) {
// Use boot JNI stub if found.
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
const void* boot_jni_stub = class_linker->FindBootJniStub(method);
if (boot_jni_stub != nullptr) {
entrypoint = boot_jni_stub;
}
}
copy->SetNativePointer(ArtMethod::EntryPointFromQuickCompiledCodeOffset(kRuntimePointerSize),
entrypoint,
kRuntimePointerSize);
if (method->IsNative()) {
StubType stub_type = method->IsCriticalNative()
? StubType::kJNIDlsymLookupCriticalTrampoline
: StubType::kJNIDlsymLookupTrampoline;
copy->SetEntryPointFromJni(header.GetOatAddress(stub_type));
} else if (method->HasCodeItem()) {
const uint8_t* code_item = reinterpret_cast<const uint8_t*>(method->GetCodeItem());
DCHECK_GE(code_item, method->GetDexFile()->DataBegin());
uint32_t code_item_offset = dchecked_integral_cast<uint32_t>(
code_item - method->GetDexFile()->DataBegin());;
copy->SetDataPtrSize(
reinterpret_cast<const void*>(code_item_offset), kRuntimePointerSize);
}
}
}
void CopyImTable(ObjPtr<mirror::Class> cls) REQUIRES_SHARED(Locks::mutator_lock_) {
ImTable* table = cls->GetImt(kRuntimePointerSize);
// If the table is null or shared and/or already emitted, we can skip.
if (table == nullptr || IsInBootImage(table) || HasNativeRelocation(table)) {
return;
}
const size_t size = ImTable::SizeInBytes(kRuntimePointerSize);
size_t offset = im_tables_.size();
im_tables_.resize(offset + size);
uint8_t* dest = im_tables_.data() + offset;
memcpy(dest, table, size);
native_relocations_.Put(table, std::make_pair(NativeRelocationKind::kImTable, offset));
}
bool HasNativeRelocation(void* ptr) const {
return native_relocations_.find(ptr) != native_relocations_.end();
}
static void LoadClassesFromReferenceProfile(
Thread* self,
const dchecked_vector<Handle<mirror::DexCache>>& dex_caches)
REQUIRES_SHARED(Locks::mutator_lock_) {
AppInfo* app_info = Runtime::Current()->GetAppInfo();
std::string profile_file = app_info->GetPrimaryApkReferenceProfile();
if (profile_file.empty()) {
return;
}
// Lock the file, it could be concurrently updated by the system. Don't block
// as this is app startup sensitive.
std::string error;
ScopedFlock profile =
LockedFile::Open(profile_file.c_str(), O_RDONLY, /*block=*/false, &error);
if (profile == nullptr) {
LOG(DEBUG) << "Couldn't lock the profile file " << profile_file << ": " << error;
return;
}
ProfileCompilationInfo profile_info(/* for_boot_image= */ false);
if (!profile_info.Load(profile->Fd())) {
LOG(DEBUG) << "Could not load profile file";
return;
}
StackHandleScope<1> hs(self);
Handle<mirror::ClassLoader> class_loader =
hs.NewHandle<mirror::ClassLoader>(dex_caches[0]->GetClassLoader());
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
ScopedTrace loading_classes("Loading classes from profile");
for (auto dex_cache : dex_caches) {
const DexFile* dex_file = dex_cache->GetDexFile();
const ArenaSet<dex::TypeIndex>* class_types = profile_info.GetClasses(*dex_file);
if (class_types == nullptr) {
// This means the profile file did not reference the dex file, which is the case
// if there's no classes and methods of that dex file in the profile.
continue;
}
for (dex::TypeIndex idx : *class_types) {
// The index is greater or equal to NumTypeIds if the type is an extra
// descriptor, not referenced by the dex file.
if (idx.index_ < dex_file->NumTypeIds()) {
ObjPtr<mirror::Class> klass = class_linker->ResolveType(idx, dex_cache, class_loader);
if (klass == nullptr) {
self->ClearException();
LOG(DEBUG) << "Failed to preload " << dex_file->PrettyType(idx);
continue;
}
}
}
}
}
bool WriteObjects(std::string* error_msg) {
ScopedTrace write_objects("Writing objects");
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
ScopedObjectAccess soa(Thread::Current());
VariableSizedHandleScope handles(soa.Self());
Handle<mirror::Class> object_array_class = handles.NewHandle(
GetClassRoot<mirror::ObjectArray<mirror::Object>>(class_linker));
Handle<mirror::ObjectArray<mirror::Object>> image_roots = handles.NewHandle(
mirror::ObjectArray<mirror::Object>::Alloc(
soa.Self(), object_array_class.Get(), ImageHeader::kImageRootsMax));
if (image_roots == nullptr) {
DCHECK(soa.Self()->IsExceptionPending());
soa.Self()->ClearException();
*error_msg = "Out of memory when trying to generate a runtime app image";
return false;
}
// Find the dex files that will be used for generating the app image.
dchecked_vector<Handle<mirror::DexCache>> dex_caches;
FindDexCaches(soa.Self(), dex_caches, handles);
if (dex_caches.size() == 0) {
*error_msg = "Did not find dex caches to generate an app image";
return false;
}
const OatDexFile* oat_dex_file = dex_caches[0]->GetDexFile()->GetOatDexFile();
VdexFile* vdex_file = oat_dex_file->GetOatFile()->GetVdexFile();
// The first entry in `dex_caches` contains the location of the primary APK.
dex_location_ = oat_dex_file->GetDexFileLocation();
size_t number_of_dex_files = vdex_file->GetNumberOfDexFiles();
if (number_of_dex_files != dex_caches.size()) {
// This means some dex files haven't been executed. For simplicity, just
// register them and recollect dex caches.
Handle<mirror::ClassLoader> loader = handles.NewHandle(dex_caches[0]->GetClassLoader());
VisitClassLoaderDexFiles(soa.Self(), loader, [&](const art::DexFile* dex_file)
REQUIRES_SHARED(Locks::mutator_lock_) {
class_linker->RegisterDexFile(*dex_file, dex_caches[0]->GetClassLoader());
return true; // Continue with other dex files.
});
dex_caches.clear();
FindDexCaches(soa.Self(), dex_caches, handles);
if (number_of_dex_files != dex_caches.size()) {
*error_msg = "Number of dex caches does not match number of dex files in the primary APK";
return false;
}
}
// If classes referenced in the reference profile are not loaded, preload
// them. This makes sure we generate a good runtime app image, even if this
// current app run did not load all startup classes.
LoadClassesFromReferenceProfile(soa.Self(), dex_caches);
// We store the checksums of the dex files used at runtime. These can be
// different compared to the vdex checksums due to compact dex.
std::vector<uint32_t> checksums(number_of_dex_files);
uint32_t checksum_index = 0;
for (const OatDexFile* current_oat_dex_file : oat_dex_file->GetOatFile()->GetOatDexFiles()) {
const DexFile::Header* header =
reinterpret_cast<const DexFile::Header*>(current_oat_dex_file->GetDexFilePointer());
checksums[checksum_index++] = header->checksum_;
}
DCHECK_EQ(checksum_index, number_of_dex_files);
// Create the fake OatHeader to store the dependencies of the image.
SafeMap<std::string, std::string> key_value_store;
Runtime* runtime = Runtime::Current();
key_value_store.Put(OatHeader::kApexVersionsKey, runtime->GetApexVersions());
key_value_store.Put(OatHeader::kBootClassPathKey,
android::base::Join(runtime->GetBootClassPathLocations(), ':'));
key_value_store.Put(OatHeader::kBootClassPathChecksumsKey,
runtime->GetBootClassPathChecksums());
key_value_store.Put(OatHeader::kClassPathKey,
oat_dex_file->GetOatFile()->GetClassLoaderContext());
key_value_store.Put(OatHeader::kConcurrentCopying,
gUseReadBarrier ? OatHeader::kTrueValue : OatHeader::kFalseValue);
std::unique_ptr<const InstructionSetFeatures> isa_features =
InstructionSetFeatures::FromCppDefines();
std::unique_ptr<OatHeader> oat_header(
OatHeader::Create(kRuntimeISA,
isa_features.get(),
number_of_dex_files,
&key_value_store));
// Create the byte array containing the oat header and dex checksums.
uint32_t checksums_size = checksums.size() * sizeof(uint32_t);
Handle<mirror::ByteArray> header_data = handles.NewHandle(
mirror::ByteArray::Alloc(soa.Self(), oat_header->GetHeaderSize() + checksums_size));
if (header_data == nullptr) {
DCHECK(soa.Self()->IsExceptionPending());
soa.Self()->ClearException();
*error_msg = "Out of memory when trying to generate a runtime app image";
return false;
}
memcpy(header_data->GetData(), oat_header.get(), oat_header->GetHeaderSize());
memcpy(header_data->GetData() + oat_header->GetHeaderSize(), checksums.data(), checksums_size);
// Create and populate the dex caches aray.
Handle<mirror::ObjectArray<mirror::Object>> dex_cache_array = handles.NewHandle(
mirror::ObjectArray<mirror::Object>::Alloc(
soa.Self(), object_array_class.Get(), dex_caches.size()));
if (dex_cache_array == nullptr) {
DCHECK(soa.Self()->IsExceptionPending());
soa.Self()->ClearException();
*error_msg = "Out of memory when trying to generate a runtime app image";
return false;
}
for (uint32_t i = 0; i < dex_caches.size(); ++i) {
dex_cache_array->Set(i, dex_caches[i].Get());
}
image_roots->Set(ImageHeader::kDexCaches, dex_cache_array.Get());
image_roots->Set(ImageHeader::kClassRoots, class_linker->GetClassRoots());
image_roots->Set(ImageHeader::kAppImageOatHeader, header_data.Get());
{
// Now that we have created all objects needed for the `image_roots`, copy
// it into the buffer. Note that this will recursively copy all objects
// contained in `image_roots`. That's acceptable as we don't have cycles,
// nor a deep graph.
ScopedAssertNoThreadSuspension sants("Writing runtime app image");
CopyObject(image_roots.Get());
}
// Emit classes defined in the app class loader (which will also indirectly
// emit dex caches and their arrays).
EmitClasses(soa.Self(), dex_cache_array);
return true;
}
class FixupVisitor {
public:
FixupVisitor(RuntimeImageHelper* image, size_t copy_offset)
: image_(image), copy_offset_(copy_offset) {}
// We do not visit native roots. These are handled with other logic.
void VisitRootIfNonNull(
[[maybe_unused]] mirror::CompressedReference<mirror::Object>* root) const {
LOG(FATAL) << "UNREACHABLE";
}
void VisitRoot([[maybe_unused]] mirror::CompressedReference<mirror::Object>* root) const {
LOG(FATAL) << "UNREACHABLE";
}
void operator()(ObjPtr<mirror::Object> obj,
MemberOffset offset,
bool is_static) const
REQUIRES_SHARED(Locks::mutator_lock_) {
// We don't copy static fields, they are being handled when we try to
// initialize the class.
ObjPtr<mirror::Object> ref =
is_static ? nullptr : obj->GetFieldObject<mirror::Object>(offset);
mirror::Object* address = image_->GetOrComputeImageAddress(ref);
mirror::Object* copy =
reinterpret_cast<mirror::Object*>(image_->objects_.data() + copy_offset_);
copy->GetFieldObjectReferenceAddr<kVerifyNone>(offset)->Assign(address);
}
// java.lang.ref.Reference visitor.
void operator()([[maybe_unused]] ObjPtr<mirror::Class> klass,
ObjPtr<mirror::Reference> ref) const REQUIRES_SHARED(Locks::mutator_lock_) {
operator()(ref, mirror::Reference::ReferentOffset(), /* is_static */ false);
}
private:
RuntimeImageHelper* image_;
size_t copy_offset_;
};
template <typename T>
void CopyNativeDexCacheArray(uint32_t num_entries,
uint32_t max_entries,
mirror::NativeArray<T>* array) {
if (array == nullptr) {
return;
}
bool only_startup = !mirror::DexCache::ShouldAllocateFullArray(num_entries, max_entries);
ArenaVector<uint8_t>& data = only_startup ? metadata_ : dex_cache_arrays_;
NativeRelocationKind relocation_kind = only_startup
? NativeRelocationKind::kStartupNativeDexCacheArray
: NativeRelocationKind::kFullNativeDexCacheArray;
size_t size = num_entries * sizeof(void*);
// We need to reserve space to store `num_entries` because ImageSpace doesn't have
// access to the dex files when relocating dex caches.
size_t offset = RoundUp(data.size(), sizeof(void*)) + sizeof(uintptr_t);
data.resize(RoundUp(data.size(), sizeof(void*)) + sizeof(uintptr_t) + size);
reinterpret_cast<uintptr_t*>(data.data() + offset)[-1] = num_entries;
// Copy each entry individually. We cannot use memcpy, as the entries may be
// updated concurrently by other mutator threads.
mirror::NativeArray<T>* copy = reinterpret_cast<mirror::NativeArray<T>*>(data.data() + offset);
for (uint32_t i = 0; i < num_entries; ++i) {
copy->Set(i, array->Get(i));
}
native_relocations_.Put(array, std::make_pair(relocation_kind, offset));
}
template <typename T>
mirror::GcRootArray<T>* CreateGcRootDexCacheArray(uint32_t num_entries,
uint32_t max_entries,
mirror::GcRootArray<T>* array) {
if (array == nullptr) {
return nullptr;
}
bool only_startup = !mirror::DexCache::ShouldAllocateFullArray(num_entries, max_entries);
ArenaVector<uint8_t>& data = only_startup ? metadata_ : dex_cache_arrays_;
NativeRelocationKind relocation_kind = only_startup
? NativeRelocationKind::kStartupNativeDexCacheArray
: NativeRelocationKind::kFullNativeDexCacheArray;
size_t size = num_entries * sizeof(GcRoot<T>);
// We need to reserve space to store `num_entries` because ImageSpace doesn't have
// access to the dex files when relocating dex caches.
static_assert(sizeof(GcRoot<T>) == sizeof(uint32_t));
size_t offset = data.size() + sizeof(uint32_t);
data.resize(data.size() + sizeof(uint32_t) + size);
reinterpret_cast<uint32_t*>(data.data() + offset)[-1] = num_entries;
native_relocations_.Put(array, std::make_pair(relocation_kind, offset));
return reinterpret_cast<mirror::GcRootArray<T>*>(data.data() + offset);
}
static bool EmitDexCacheArrays() {
// We need to treat dex cache arrays specially in an image for userfaultfd.
// Disable for now. See b/270936884.
return !gUseUserfaultfd;
}
uint32_t CopyDexCache(ObjPtr<mirror::DexCache> cache) REQUIRES_SHARED(Locks::mutator_lock_) {
auto it = dex_caches_.find(cache->GetDexFile());
if (it != dex_caches_.end()) {
return it->second;
}
uint32_t offset = CopyObject(cache);
dex_caches_.Put(cache->GetDexFile(), offset);
// For dex caches, clear pointers to data that will be set at runtime.
mirror::Object* copy = reinterpret_cast<mirror::Object*>(objects_.data() + offset);
reinterpret_cast<mirror::DexCache*>(copy)->ResetNativeArrays();
reinterpret_cast<mirror::DexCache*>(copy)->SetDexFile(nullptr);
if (!EmitDexCacheArrays()) {
return offset;
}
// Copy the ArtMethod array.
mirror::NativeArray<ArtMethod>* resolved_methods = cache->GetResolvedMethodsArray();
CopyNativeDexCacheArray(cache->GetDexFile()->NumMethodIds(),
mirror::DexCache::kDexCacheMethodCacheSize,
resolved_methods);
// Store the array pointer in the dex cache, which will be relocated at the end.
reinterpret_cast<mirror::DexCache*>(copy)->SetResolvedMethodsArray(resolved_methods);
// Copy the ArtField array.
mirror::NativeArray<ArtField>* resolved_fields = cache->GetResolvedFieldsArray();
CopyNativeDexCacheArray(cache->GetDexFile()->NumFieldIds(),
mirror::DexCache::kDexCacheFieldCacheSize,
resolved_fields);
// Store the array pointer in the dex cache, which will be relocated at the end.
reinterpret_cast<mirror::DexCache*>(copy)->SetResolvedFieldsArray(resolved_fields);
// Copy the type array.
mirror::GcRootArray<mirror::Class>* resolved_types = cache->GetResolvedTypesArray();
CreateGcRootDexCacheArray(cache->GetDexFile()->NumTypeIds(),
mirror::DexCache::kDexCacheTypeCacheSize,
resolved_types);
// Store the array pointer in the dex cache, which will be relocated at the end.
reinterpret_cast<mirror::DexCache*>(copy)->SetResolvedTypesArray(resolved_types);
// Copy the string array.
mirror::GcRootArray<mirror::String>* strings = cache->GetStringsArray();
// Note: `new_strings` points to temporary data, and is only valid here.
mirror::GcRootArray<mirror::String>* new_strings =
CreateGcRootDexCacheArray(cache->GetDexFile()->NumStringIds(),
mirror::DexCache::kDexCacheStringCacheSize,
strings);
// Store the array pointer in the dex cache, which will be relocated at the end.
reinterpret_cast<mirror::DexCache*>(copy)->SetStringsArray(strings);
// The code below copies new objects, so invalidate the address we have for
// `copy`.
copy = nullptr;
if (strings != nullptr) {
for (uint32_t i = 0; i < cache->GetDexFile()->NumStringIds(); ++i) {
ObjPtr<mirror::String> str = strings->Get(i);
if (str == nullptr || IsInBootImage(str.Ptr())) {
new_strings->Set(i, str.Ptr());
} else {
uint32_t hash = static_cast<uint32_t>(str->GetStoredHashCode());
DCHECK_EQ(hash, static_cast<uint32_t>(str->ComputeHashCode()))
<< "Dex cache strings should be interned";
auto it2 = intern_table_.FindWithHash(str.Ptr(), hash);
if (it2 == intern_table_.end()) {
uint32_t string_offset = CopyObject(str);
uint32_t address = image_begin_ + string_offset + sizeof(ImageHeader);
intern_table_.InsertWithHash(address, hash);
new_strings->Set(i, reinterpret_cast<mirror::String*>(address));
} else {
new_strings->Set(i, reinterpret_cast<mirror::String*>(*it2));
}
// To not confuse string references from the dex cache object and
// string references from the array, we put an offset bigger than the
// size of a DexCache object. ClassLinker::VisitInternedStringReferences
// knows how to decode this offset.
string_reference_offsets_.emplace_back(
sizeof(ImageHeader) + offset, sizeof(mirror::DexCache) + i);
}
}
}
return offset;
}
bool IsInitialized(mirror::Class* cls) REQUIRES_SHARED(Locks::mutator_lock_) {
if (IsInBootImage(cls)) {
const OatDexFile* oat_dex_file = cls->GetDexFile().GetOatDexFile();
DCHECK(oat_dex_file != nullptr) << "We should always have an .oat file for a boot image";
uint16_t class_def_index = cls->GetDexClassDefIndex();
ClassStatus oat_file_class_status = oat_dex_file->GetOatClass(class_def_index).GetStatus();
return oat_file_class_status == ClassStatus::kVisiblyInitialized;
} else {
return cls->IsVisiblyInitialized<kVerifyNone>();
}
}
// Try to initialize `copy`. Note that `cls` may not be initialized.
// This is called after the image generation logic has visited super classes
// and super interfaces, so we can just check those directly.
bool TryInitializeClass(mirror::Class* copy, ObjPtr<mirror::Class> cls, uint32_t class_offset)
REQUIRES_SHARED(Locks::mutator_lock_) {
if (!cls->IsVerified()) {
return false;
}
if (cls->IsArrayClass()) {
return true;
}
// Check if we have been able to initialize the super class.
mirror::Class* super = GetClassContent(cls->GetSuperClass());
DCHECK(super != nullptr)
<< "App image classes should always have a super class: " << cls->PrettyClass();
if (!IsInitialized(super)) {
return false;
}
// We won't initialize class with class initializers.
if (cls->FindClassInitializer(kRuntimePointerSize) != nullptr) {
return false;
}
// For non-interface classes, we require all implemented interfaces to be
// initialized.
if (!cls->IsInterface()) {
for (size_t i = 0; i < cls->NumDirectInterfaces(); i++) {
mirror::Class* itf = GetClassContent(cls->GetDirectInterface(i));
if (!IsInitialized(itf)) {
return false;
}
}
}
// Trivial case: no static fields.
if (cls->NumStaticFields() == 0u) {
return true;
}
// Go over all static fields and try to initialize them.
EncodedStaticFieldValueIterator it(cls->GetDexFile(), *cls->GetClassDef());
if (!it.HasNext()) {
return true;
}
// Temporary string offsets in case we failed to initialize the class. We
// will add the offsets at the end of this method if we are successful.
ArenaVector<AppImageReferenceOffsetInfo> string_offsets(allocator_.Adapter());
ClassLinker* linker = Runtime::Current()->GetClassLinker();
ClassAccessor accessor(cls->GetDexFile(), *cls->GetClassDef());
for (const ClassAccessor::Field& field : accessor.GetStaticFields()) {
if (!it.HasNext()) {
break;
}
ArtField* art_field = linker->LookupResolvedField(field.GetIndex(),
cls->GetDexCache(),
cls->GetClassLoader(),
/* is_static= */ true);
DCHECK_NE(art_field, nullptr);
MemberOffset offset(art_field->GetOffset());
switch (it.GetValueType()) {
case EncodedArrayValueIterator::ValueType::kBoolean:
copy->SetFieldBoolean<false>(offset, it.GetJavaValue().z);
break;
case EncodedArrayValueIterator::ValueType::kByte:
copy->SetFieldByte<false>(offset, it.GetJavaValue().b);
break;
case EncodedArrayValueIterator::ValueType::kShort:
copy->SetFieldShort<false>(offset, it.GetJavaValue().s);
break;
case EncodedArrayValueIterator::ValueType::kChar:
copy->SetFieldChar<false>(offset, it.GetJavaValue().c);
break;
case EncodedArrayValueIterator::ValueType::kInt:
copy->SetField32<false>(offset, it.GetJavaValue().i);
break;
case EncodedArrayValueIterator::ValueType::kLong:
copy->SetField64<false>(offset, it.GetJavaValue().j);
break;
case EncodedArrayValueIterator::ValueType::kFloat:
copy->SetField32<false>(offset, it.GetJavaValue().i);
break;
case EncodedArrayValueIterator::ValueType::kDouble:
copy->SetField64<false>(offset, it.GetJavaValue().j);
break;
case EncodedArrayValueIterator::ValueType::kNull:
copy->SetFieldObject<false>(offset, nullptr);
break;
case EncodedArrayValueIterator::ValueType::kString: {
ObjPtr<mirror::String> str =
linker->LookupString(dex::StringIndex(it.GetJavaValue().i), cls->GetDexCache());
mirror::String* str_copy = nullptr;
if (str == nullptr) {
// String wasn't created yet.
return false;
} else if (IsInBootImage(str.Ptr())) {
str_copy = str.Ptr();
} else {
uint32_t hash = static_cast<uint32_t>(str->GetStoredHashCode());
DCHECK_EQ(hash, static_cast<uint32_t>(str->ComputeHashCode()))
<< "Dex cache strings should be interned";
auto string_it = intern_table_.FindWithHash(str.Ptr(), hash);
if (string_it == intern_table_.end()) {
// The string must be interned.
uint32_t string_offset = CopyObject(str);
// Reload the class copy after having copied the string.
copy = reinterpret_cast<mirror::Class*>(objects_.data() + class_offset);
uint32_t address = image_begin_ + string_offset + sizeof(ImageHeader);
intern_table_.InsertWithHash(address, hash);
str_copy = reinterpret_cast<mirror::String*>(address);
} else {
str_copy = reinterpret_cast<mirror::String*>(*string_it);
}
string_offsets.emplace_back(sizeof(ImageHeader) + class_offset, offset.Int32Value());
}
uint8_t* raw_addr = reinterpret_cast<uint8_t*>(copy) + offset.Int32Value();
mirror::HeapReference<mirror::Object>* objref_addr =
reinterpret_cast<mirror::HeapReference<mirror::Object>*>(raw_addr);
objref_addr->Assign</* kIsVolatile= */ false>(str_copy);
break;
}
case EncodedArrayValueIterator::ValueType::kType: {
// Note that it may be that the referenced type hasn't been processed
// yet by the image generation logic. In this case we bail out for
// simplicity.
ObjPtr<mirror::Class> type =
linker->LookupResolvedType(dex::TypeIndex(it.GetJavaValue().i), cls);
mirror::Class* type_copy = nullptr;
if (type == nullptr) {
// Class wasn't resolved yet.
return false;
} else if (IsInBootImage(type.Ptr())) {
// Make sure the type is in our class table.
uint32_t hash = type->DescriptorHash();
class_table_.InsertWithHash(ClassTable::TableSlot(type.Ptr(), hash), hash);
type_copy = type.Ptr();
} else if (type->IsArrayClass()) {
std::string class_name;
type->GetDescriptor(&class_name);
auto class_it = array_classes_.find(class_name);
if (class_it == array_classes_.end()) {
return false;
}
type_copy = reinterpret_cast<mirror::Class*>(
image_begin_ + sizeof(ImageHeader) + class_it->second);
} else {
const dex::ClassDef* class_def = type->GetClassDef();
DCHECK_NE(class_def, nullptr);
auto class_it = classes_.find(class_def);
if (class_it == classes_.end()) {
return false;
}
type_copy = reinterpret_cast<mirror::Class*>(
image_begin_ + sizeof(ImageHeader) + class_it->second);
}
uint8_t* raw_addr = reinterpret_cast<uint8_t*>(copy) + offset.Int32Value();
mirror::HeapReference<mirror::Object>* objref_addr =
reinterpret_cast<mirror::HeapReference<mirror::Object>*>(raw_addr);
objref_addr->Assign</* kIsVolatile= */ false>(type_copy);
break;
}
default:
LOG(FATAL) << "Unreachable";
}
it.Next();
}
// We have successfully initialized the class, we can now record the string
// offsets.
string_reference_offsets_.insert(
string_reference_offsets_.end(), string_offsets.begin(), string_offsets.end());
return true;
}
uint32_t CopyClass(ObjPtr<mirror::Class> cls) REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(!cls->IsBootStrapClassLoaded());
uint32_t offset = 0u;
if (cls->IsArrayClass()) {
std::string class_name;
cls->GetDescriptor(&class_name);
auto it = array_classes_.find(class_name);
if (it != array_classes_.end()) {
return it->second;
}
offset = CopyObject(cls);
array_classes_.Put(class_name, offset);
} else {
const dex::ClassDef* class_def = cls->GetClassDef();
auto it = classes_.find(class_def);
if (it != classes_.end()) {
return it->second;
}
offset = CopyObject(cls);
classes_.Put(class_def, offset);
}
uint32_t hash = cls->DescriptorHash();
// Save the hash, the `HashSet` implementation requires to find it.
class_hashes_.Put(offset, hash);
uint32_t class_image_address = image_begin_ + sizeof(ImageHeader) + offset;
bool inserted =
class_table_.InsertWithHash(ClassTable::TableSlot(class_image_address, hash), hash).second;
DCHECK(inserted) << "Class " << cls->PrettyDescriptor()
<< " (" << cls.Ptr() << ") already inserted";
// Clear internal state.
mirror::Class* copy = reinterpret_cast<mirror::Class*>(objects_.data() + offset);
copy->SetClinitThreadId(static_cast<pid_t>(0u));
if (cls->IsArrayClass()) {
DCHECK(copy->IsVisiblyInitialized());
} else {
copy->SetStatusInternal(cls->IsVerified() ? ClassStatus::kVerified : ClassStatus::kResolved);
}
// Clear static field values.
auto clear_class = [&] () REQUIRES_SHARED(Locks::mutator_lock_) {
MemberOffset static_offset = cls->GetFirstReferenceStaticFieldOffset(kRuntimePointerSize);
memset(objects_.data() + offset + static_offset.Uint32Value(),
0,
cls->GetClassSize() - static_offset.Uint32Value());
};
clear_class();
bool is_class_initialized = TryInitializeClass(copy, cls, offset);
// Reload the copy, it may have moved after `TryInitializeClass`.
copy = reinterpret_cast<mirror::Class*>(objects_.data() + offset);
if (is_class_initialized) {
copy->SetStatusInternal(ClassStatus::kVisiblyInitialized);
if (!cls->IsArrayClass() && !cls->IsFinalizable()) {
copy->SetObjectSizeAllocFastPath(RoundUp(cls->GetObjectSize(), kObjectAlignment));
}
if (cls->IsInterface()) {
copy->SetAccessFlags(copy->GetAccessFlags() | kAccRecursivelyInitialized);
}
} else {
// If we fail to initialize, remove initialization related flags and
// clear again.
copy->SetObjectSizeAllocFastPath(std::numeric_limits<uint32_t>::max());
copy->SetAccessFlags(copy->GetAccessFlags() & ~kAccRecursivelyInitialized);
clear_class();
}
CopyFieldArrays(cls, class_image_address);
CopyMethodArrays(cls, class_image_address, is_class_initialized);
if (cls->ShouldHaveImt()) {
CopyImTable(cls);
}
return offset;
}
// Copy `obj` in `objects_` and relocate references. Returns the offset
// within our buffer.
uint32_t CopyObject(ObjPtr<mirror::Object> obj) REQUIRES_SHARED(Locks::mutator_lock_) {
// Copy the object in `objects_`.
size_t object_size = obj->SizeOf();
size_t offset = objects_.size();
DCHECK(IsAligned<kObjectAlignment>(offset));
object_offsets_.push_back(offset);
objects_.resize(RoundUp(offset + object_size, kObjectAlignment));
mirror::Object* copy = reinterpret_cast<mirror::Object*>(objects_.data() + offset);
mirror::Object::CopyRawObjectData(
reinterpret_cast<uint8_t*>(copy), obj, object_size - sizeof(mirror::Object));
// Clear any lockword data.
copy->SetLockWord(LockWord::Default(), /* as_volatile= */ false);
copy->SetClass(obj->GetClass());
// Fixup reference pointers.
FixupVisitor visitor(this, offset);
obj->VisitReferences</*kVisitNativeRoots=*/ false>(visitor, visitor);
if (obj->IsString()) {
// Ensure a string always has a hashcode stored. This is checked at
// runtime because boot images don't want strings dirtied due to hashcode.
reinterpret_cast<mirror::String*>(copy)->GetHashCode();
}
object_section_size_ += RoundUp(object_size, kObjectAlignment);
return offset;
}
class CollectDexCacheVisitor : public DexCacheVisitor {
public:
explicit CollectDexCacheVisitor(VariableSizedHandleScope& handles) : handles_(handles) {}
void Visit(ObjPtr<mirror::DexCache> dex_cache)
REQUIRES_SHARED(Locks::dex_lock_, Locks::mutator_lock_) override {
dex_caches_.push_back(handles_.NewHandle(dex_cache));
}
const std::vector<Handle<mirror::DexCache>>& GetDexCaches() const {
return dex_caches_;
}
private:
VariableSizedHandleScope& handles_;
std::vector<Handle<mirror::DexCache>> dex_caches_;
};
// Find dex caches corresponding to the primary APK.
void FindDexCaches(Thread* self,
dchecked_vector<Handle<mirror::DexCache>>& dex_caches,
VariableSizedHandleScope& handles)
REQUIRES_SHARED(Locks::mutator_lock_) {
ScopedTrace trace("Find dex caches");
DCHECK(dex_caches.empty());
// Collect all dex caches.
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
CollectDexCacheVisitor visitor(handles);
{
ReaderMutexLock mu(self, *Locks::dex_lock_);
class_linker->VisitDexCaches(&visitor);
}
// Find the primary APK.
AppInfo* app_info = Runtime::Current()->GetAppInfo();
for (Handle<mirror::DexCache> cache : visitor.GetDexCaches()) {
if (app_info->GetRegisteredCodeType(cache->GetDexFile()->GetLocation()) ==
AppInfo::CodeType::kPrimaryApk) {
dex_caches.push_back(handles.NewHandle(cache.Get()));
break;
}
}
if (dex_caches.empty()) {
return;
}
const OatDexFile* oat_dex_file = dex_caches[0]->GetDexFile()->GetOatDexFile();
if (oat_dex_file == nullptr) {
// We need a .oat file for loading an app image;
dex_caches.clear();
return;
}
// Store the dex caches in the order in which their corresponding dex files
// are stored in the oat file. When we check for checksums at the point of
// loading the image, we rely on this order.
for (const OatDexFile* current : oat_dex_file->GetOatFile()->GetOatDexFiles()) {
if (current != oat_dex_file) {
for (Handle<mirror::DexCache> cache : visitor.GetDexCaches()) {
if (cache->GetDexFile()->GetOatDexFile() == current) {
dex_caches.push_back(handles.NewHandle(cache.Get()));
}
}
}
}
}
static uint64_t PointerToUint64(void* ptr) {
return reinterpret_cast64<uint64_t>(ptr);
}
void WriteImageMethods() {
ScopedObjectAccess soa(Thread::Current());
// We can just use plain runtime pointers.
Runtime* runtime = Runtime::Current();
header_.image_methods_[ImageHeader::kResolutionMethod] =
PointerToUint64(runtime->GetResolutionMethod());
header_.image_methods_[ImageHeader::kImtConflictMethod] =
PointerToUint64(runtime->GetImtConflictMethod());
header_.image_methods_[ImageHeader::kImtUnimplementedMethod] =
PointerToUint64(runtime->GetImtUnimplementedMethod());
header_.image_methods_[ImageHeader::kSaveAllCalleeSavesMethod] =
PointerToUint64(runtime->GetCalleeSaveMethod(CalleeSaveType::kSaveAllCalleeSaves));
header_.image_methods_[ImageHeader::kSaveRefsOnlyMethod] =
PointerToUint64(runtime->GetCalleeSaveMethod(CalleeSaveType::kSaveRefsOnly));
header_.image_methods_[ImageHeader::kSaveRefsAndArgsMethod] =
PointerToUint64(runtime->GetCalleeSaveMethod(CalleeSaveType::kSaveRefsAndArgs));
header_.image_methods_[ImageHeader::kSaveEverythingMethod] =
PointerToUint64(runtime->GetCalleeSaveMethod(CalleeSaveType::kSaveEverything));
header_.image_methods_[ImageHeader::kSaveEverythingMethodForClinit] =
PointerToUint64(runtime->GetCalleeSaveMethod(CalleeSaveType::kSaveEverythingForClinit));
header_.image_methods_[ImageHeader::kSaveEverythingMethodForSuspendCheck] =
PointerToUint64(
runtime->GetCalleeSaveMethod(CalleeSaveType::kSaveEverythingForSuspendCheck));
}
// Header for the image, created at the end once we know the size of all
// sections.
ImageHeader header_;
// Allocator for the various data structures to allocate while generating the
// image.
ArenaAllocator allocator_;
// Contents of the various sections.
ArenaVector<uint8_t> objects_;
ArenaVector<uint8_t> art_fields_;
ArenaVector<uint8_t> art_methods_;
ArenaVector<uint8_t> im_tables_;
ArenaVector<uint8_t> metadata_;
ArenaVector<uint8_t> dex_cache_arrays_;
ArenaVector<AppImageReferenceOffsetInfo> string_reference_offsets_;
// Bitmap of live objects in `objects_`. Populated from `object_offsets_`
// once we know `object_section_size`.
gc::accounting::ContinuousSpaceBitmap image_bitmap_;
// Sections stored in the header.
ArenaVector<ImageSection> sections_;
// A list of offsets in `objects_` where objects begin.
ArenaVector<uint32_t> object_offsets_;
ArenaSafeMap<const dex::ClassDef*, uint32_t> classes_;
ArenaSafeMap<std::string, uint32_t> array_classes_;
ArenaSafeMap<const DexFile*, uint32_t> dex_caches_;
ArenaSafeMap<uint32_t, uint32_t> class_hashes_;
ArenaSafeMap<void*, std::pair<NativeRelocationKind, uint32_t>> native_relocations_;
// Cached values of boot image information.
const uint32_t boot_image_begin_;
const uint32_t boot_image_size_;
// Where the image begins: just after the boot image.
const uint32_t image_begin_;
// Size of the `kSectionObjects` section.
size_t object_section_size_;
// The location of the primary APK / dex file.
std::string dex_location_;
// The intern table for strings that we will write to disk.
InternTableSet intern_table_;
// The class table holding classes that we will write to disk.
ClassTableSet class_table_;
friend class ClassDescriptorHash;
friend class PruneVisitor;
friend class NativePointerVisitor;
};
std::string RuntimeImage::GetRuntimeImageDir(const std::string& app_data_dir) {
if (app_data_dir.empty()) {
// The data directory is empty for tests.
return "";
}
return app_data_dir + "/cache/oat_primary/";
}
// Note: this may return a relative path for tests.
std::string RuntimeImage::GetRuntimeImagePath(const std::string& app_data_dir,
const std::string& dex_location,
const std::string& isa) {
std::string basename = android::base::Basename(dex_location);
std::string filename = ReplaceFileExtension(basename, "art");
return GetRuntimeImageDir(app_data_dir) + isa + "/" + filename;
}
std::string RuntimeImage::GetRuntimeImagePath(const std::string& dex_location) {
return GetRuntimeImagePath(Runtime::Current()->GetProcessDataDirectory(),
dex_location,
GetInstructionSetString(kRuntimeISA));
}
static bool EnsureDirectoryExists(const std::string& directory, std::string* error_msg) {
if (!OS::DirectoryExists(directory.c_str())) {
static constexpr mode_t kDirectoryMode = S_IRWXU | S_IRGRP | S_IXGRP| S_IROTH | S_IXOTH;
if (mkdir(directory.c_str(), kDirectoryMode) != 0) {
*error_msg =
StringPrintf("Could not create directory %s: %s", directory.c_str(), strerror(errno));
return false;
}
}
return true;
}
bool RuntimeImage::WriteImageToDisk(std::string* error_msg) {
gc::Heap* heap = Runtime::Current()->GetHeap();
if (!heap->HasBootImageSpace()) {
*error_msg = "Cannot generate an app image without a boot image";
return false;
}
std::string oat_path = GetRuntimeImageDir(Runtime::Current()->GetProcessDataDirectory());
if (!oat_path.empty() && !EnsureDirectoryExists(oat_path, error_msg)) {
return false;
}
ScopedTrace generate_image_trace("Generating runtime image");
std::unique_ptr<RuntimeImageHelper> image(new RuntimeImageHelper(heap));
if (!image->Generate(error_msg)) {
return false;
}
ScopedTrace write_image_trace("Writing runtime image to disk");
const std::string path = GetRuntimeImagePath(image->GetDexLocation());
if (!EnsureDirectoryExists(android::base::Dirname(path), error_msg)) {
return false;
}
// We first generate the app image in a temporary file, which we will then
// move to `path`.
const std::string temp_path = ReplaceFileExtension(path, std::to_string(getpid()) + ".tmp");
ImageFileGuard image_file;
image_file.reset(OS::CreateEmptyFileWriteOnly(temp_path.c_str()));
if (image_file == nullptr) {
*error_msg = "Could not open " + temp_path + " for writing";
return false;
}
std::vector<uint8_t> full_data(image->GetHeader()->GetImageSize());
image->FillData(full_data);
// Specify default block size of 512K to enable parallel image decompression.
static constexpr size_t kMaxImageBlockSize = 524288;
// Use LZ4 as good compromise between CPU time and compression. LZ4HC
// empirically takes 10x more time compressing.
static constexpr ImageHeader::StorageMode kImageStorageMode = ImageHeader::kStorageModeLZ4;
// Note: no need to update the checksum of the runtime app image: we have no
// use for it, and computing it takes CPU time.
if (!image->GetHeader()->WriteData(
image_file,
full_data.data(),
reinterpret_cast<const uint8_t*>(image->GetImageBitmap().Begin()),
kImageStorageMode,
kMaxImageBlockSize,
/* update_checksum= */ false,
error_msg)) {
return false;
}
if (!image_file.WriteHeaderAndClose(temp_path, image->GetHeader(), error_msg)) {
return false;
}
if (rename(temp_path.c_str(), path.c_str()) != 0) {
*error_msg =
"Failed to move runtime app image to " + path + ": " + std::string(strerror(errno));
// Unlink directly: we cannot use `out` as we have closed it.
unlink(temp_path.c_str());
return false;
}
return true;
}
} // namespace art