runtime/class_table.cc - platform/art - Gitiles

 /*
  * Copyright (C) 2015 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 "class_table-inl.h"

 #include "base/stl_util.h"
 #include "mirror/class-inl.h"
 #include "oat_file.h"

 namespace art {

 ClassTable::ClassTable() : lock_("Class loader classes", kClassLoaderClassesLock) {
   Runtime* const runtime = Runtime::Current();
   classes_.push_back(ClassSet(runtime->GetHashTableMinLoadFactor(),
                               runtime->GetHashTableMaxLoadFactor()));
 }

 void ClassTable::FreezeSnapshot() {
   WriterMutexLock mu(Thread::Current(), lock_);
   classes_.push_back(ClassSet());
 }

 bool ClassTable::Contains(ObjPtr<mirror::Class> klass) {
   return LookupByDescriptor(klass) == klass;
 }

 ObjPtr<mirror::Class> ClassTable::LookupByDescriptor(ObjPtr<mirror::Class> klass) {
   ReaderMutexLock mu(Thread::Current(), lock_);
   TableSlot slot(klass);
   for (ClassSet& class_set : classes_) {
     auto it = class_set.find(slot);
     if (it != class_set.end()) {
       return it->Read();
     }
   }
   return nullptr;
 }

 ObjPtr<mirror::Class> ClassTable::UpdateClass(const char* descriptor,
                                               ObjPtr<mirror::Class> klass,
                                               size_t hash) {
   WriterMutexLock mu(Thread::Current(), lock_);
   // Should only be updating latest table.
   DescriptorHashPair pair(descriptor, hash);
   auto existing_it = classes_.back().FindWithHash(pair, hash);
   if (kIsDebugBuild && existing_it == classes_.back().end()) {
     for (const ClassSet& class_set : classes_) {
       if (class_set.FindWithHash(pair, hash) != class_set.end()) {
         LOG(FATAL) << "Updating class found in frozen table " << descriptor;
       }
     }
     LOG(FATAL) << "Updating class not found " << descriptor;
   }
   const ObjPtr<mirror::Class> existing = existing_it->Read();
   CHECK_NE(existing, klass) << descriptor;
   CHECK(!existing->IsResolved()) << descriptor;
   CHECK_EQ(klass->GetStatus(), ClassStatus::kResolving) << descriptor;
   CHECK(!klass->IsTemp()) << descriptor;
   VerifyObject(klass);
   // Update the element in the hash set with the new class. This is safe to do since the descriptor
   // doesn't change.
   *existing_it = TableSlot(klass, hash);
   return existing;
 }

 size_t ClassTable::CountDefiningLoaderClasses(ObjPtr<mirror::ClassLoader> defining_loader,
                                               const ClassSet& set) const {
   size_t count = 0;
   for (const TableSlot& root : set) {
     if (root.Read()->GetClassLoader() == defining_loader) {
       ++count;
     }
   }
   return count;
 }

 size_t ClassTable::NumZygoteClasses(ObjPtr<mirror::ClassLoader> defining_loader) const {
   ReaderMutexLock mu(Thread::Current(), lock_);
   size_t sum = 0;
   for (size_t i = 0; i < classes_.size() - 1; ++i) {
     sum += CountDefiningLoaderClasses(defining_loader, classes_[i]);
   }
   return sum;
 }

 size_t ClassTable::NumNonZygoteClasses(ObjPtr<mirror::ClassLoader> defining_loader) const {
   ReaderMutexLock mu(Thread::Current(), lock_);
   return CountDefiningLoaderClasses(defining_loader, classes_.back());
 }

 size_t ClassTable::NumReferencedZygoteClasses() const {
   ReaderMutexLock mu(Thread::Current(), lock_);
   size_t sum = 0;
   for (size_t i = 0; i < classes_.size() - 1; ++i) {
     sum += classes_[i].size();
   }
   return sum;
 }

 size_t ClassTable::NumReferencedNonZygoteClasses() const {
   ReaderMutexLock mu(Thread::Current(), lock_);
   return classes_.back().size();
 }

 ObjPtr<mirror::Class> ClassTable::Lookup(const char* descriptor, size_t hash) {
   DescriptorHashPair pair(descriptor, hash);
   ReaderMutexLock mu(Thread::Current(), lock_);
   for (ClassSet& class_set : classes_) {
     auto it = class_set.FindWithHash(pair, hash);
     if (it != class_set.end()) {
       return it->Read();
     }
   }
   return nullptr;
 }

 ObjPtr<mirror::Class> ClassTable::TryInsert(ObjPtr<mirror::Class> klass) {
   TableSlot slot(klass);
   WriterMutexLock mu(Thread::Current(), lock_);
   for (ClassSet& class_set : classes_) {
     auto it = class_set.find(slot);
     if (it != class_set.end()) {
       return it->Read();
     }
   }
   classes_.back().insert(slot);
   return klass;
 }

 void ClassTable::Insert(ObjPtr<mirror::Class> klass) {
   const uint32_t hash = TableSlot::HashDescriptor(klass);
   WriterMutexLock mu(Thread::Current(), lock_);
   classes_.back().InsertWithHash(TableSlot(klass, hash), hash);
 }

 void ClassTable::CopyWithoutLocks(const ClassTable& source_table) {
   if (kIsDebugBuild) {
     for (ClassSet& class_set : classes_) {
       CHECK(class_set.empty());
     }
   }
   for (const ClassSet& class_set : source_table.classes_) {
     for (const TableSlot& slot : class_set) {
       classes_.back().insert(slot);
     }
   }
 }

 void ClassTable::InsertWithoutLocks(ObjPtr<mirror::Class> klass) {
   const uint32_t hash = TableSlot::HashDescriptor(klass);
   classes_.back().InsertWithHash(TableSlot(klass, hash), hash);
 }

 void ClassTable::InsertWithHash(ObjPtr<mirror::Class> klass, size_t hash) {
   WriterMutexLock mu(Thread::Current(), lock_);
   classes_.back().InsertWithHash(TableSlot(klass, hash), hash);
 }

 bool ClassTable::Remove(const char* descriptor) {
   DescriptorHashPair pair(descriptor, ComputeModifiedUtf8Hash(descriptor));
   WriterMutexLock mu(Thread::Current(), lock_);
   for (ClassSet& class_set : classes_) {
     auto it = class_set.find(pair);
     if (it != class_set.end()) {
       class_set.erase(it);
       return true;
     }
   }
   return false;
 }

 uint32_t ClassTable::ClassDescriptorHashEquals::operator()(const TableSlot& slot)
     const {
   std::string temp;
   // No read barrier needed, we're reading a chain of constant references for comparison
   // with null and retrieval of constant primitive data. See ReadBarrierOption.
   return ComputeModifiedUtf8Hash(slot.Read<kWithoutReadBarrier>()->GetDescriptor(&temp));
 }

 bool ClassTable::ClassDescriptorHashEquals::operator()(const TableSlot& a,
                                                        const TableSlot& b) const {
   // No read barrier needed, we're reading a chain of constant references for comparison
   // with null and retrieval of constant primitive data. See ReadBarrierOption.
   if (a.Hash() != b.Hash()) {
     std::string temp;
     DCHECK(!a.Read<kWithoutReadBarrier>()->DescriptorEquals(
         b.Read<kWithoutReadBarrier>()->GetDescriptor(&temp)));
     return false;
   }
   std::string temp;
   return a.Read<kWithoutReadBarrier>()->DescriptorEquals(
       b.Read<kWithoutReadBarrier>()->GetDescriptor(&temp));
 }

 bool ClassTable::ClassDescriptorHashEquals::operator()(const TableSlot& a,
                                                        const DescriptorHashPair& b) const {
   // No read barrier needed, we're reading a chain of constant references for comparison
   // with null and retrieval of constant primitive data. See ReadBarrierOption.
   if (!a.MaskedHashEquals(b.second)) {
     DCHECK(!a.Read<kWithoutReadBarrier>()->DescriptorEquals(b.first));
     return false;
   }
   return a.Read<kWithoutReadBarrier>()->DescriptorEquals(b.first);
 }

 uint32_t ClassTable::ClassDescriptorHashEquals::operator()(const DescriptorHashPair& pair) const {
   return ComputeModifiedUtf8Hash(pair.first);
 }

 bool ClassTable::InsertStrongRoot(ObjPtr<mirror::Object> obj) {
   WriterMutexLock mu(Thread::Current(), lock_);
   DCHECK(obj != nullptr);
   for (GcRoot<mirror::Object>& root : strong_roots_) {
     if (root.Read() == obj) {
       return false;
     }
   }
   strong_roots_.push_back(GcRoot<mirror::Object>(obj));
   // If `obj` is a dex cache associated with a new oat file with GC roots, add it to oat_files_.
   if (obj->IsDexCache()) {
     const DexFile* dex_file = ObjPtr<mirror::DexCache>::DownCast(obj)->GetDexFile();
     if (dex_file != nullptr && dex_file->GetOatDexFile() != nullptr) {
       const OatFile* oat_file = dex_file->GetOatDexFile()->GetOatFile();
       if (oat_file != nullptr && !oat_file->GetBssGcRoots().empty()) {
         InsertOatFileLocked(oat_file);  // Ignore return value.
       }
     }
   }
   return true;
 }

 bool ClassTable::InsertOatFile(const OatFile* oat_file) {
   WriterMutexLock mu(Thread::Current(), lock_);
   return InsertOatFileLocked(oat_file);
 }

 bool ClassTable::InsertOatFileLocked(const OatFile* oat_file) {
   if (ContainsElement(oat_files_, oat_file)) {
     return false;
   }
   oat_files_.push_back(oat_file);
   return true;
 }

 size_t ClassTable::WriteToMemory(uint8_t* ptr) const {
   ReaderMutexLock mu(Thread::Current(), lock_);
   ClassSet combined;
   // Combine all the class sets in case there are multiple, also adjusts load factor back to
   // default in case classes were pruned.
   for (const ClassSet& class_set : classes_) {
     for (const TableSlot& root : class_set) {
       combined.insert(root);
     }
   }
   const size_t ret = combined.WriteToMemory(ptr);
   // Sanity check.
   if (kIsDebugBuild && ptr != nullptr) {
     size_t read_count;
     ClassSet class_set(ptr, /*make copy*/false, &read_count);
     class_set.Verify();
   }
   return ret;
 }

 size_t ClassTable::ReadFromMemory(uint8_t* ptr) {
   size_t read_count = 0;
   AddClassSet(ClassSet(ptr, /*make copy*/false, &read_count));
   return read_count;
 }

 void ClassTable::AddClassSet(ClassSet&& set) {
   WriterMutexLock mu(Thread::Current(), lock_);
   classes_.insert(classes_.begin(), std::move(set));
 }

 void ClassTable::ClearStrongRoots() {
   WriterMutexLock mu(Thread::Current(), lock_);
   oat_files_.clear();
   strong_roots_.clear();
 }

 ClassTable::TableSlot::TableSlot(ObjPtr<mirror::Class> klass)
     : TableSlot(klass, HashDescriptor(klass)) {}

 uint32_t ClassTable::TableSlot::HashDescriptor(ObjPtr<mirror::Class> klass) {
   std::string temp;
   return ComputeModifiedUtf8Hash(klass->GetDescriptor(&temp));
 }

 }  // namespace art
	/*
	* Copyright (C) 2015 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 "class_table-inl.h"

	#include "base/stl_util.h"
	#include "mirror/class-inl.h"
	#include "oat_file.h"

	namespace art {

	ClassTable::ClassTable() : lock_("Class loader classes", kClassLoaderClassesLock) {
	Runtime* const runtime = Runtime::Current();
	classes_.push_back(ClassSet(runtime->GetHashTableMinLoadFactor(),
	runtime->GetHashTableMaxLoadFactor()));
	}

	void ClassTable::FreezeSnapshot() {
	WriterMutexLock mu(Thread::Current(), lock_);
	classes_.push_back(ClassSet());
	}

	bool ClassTable::Contains(ObjPtr<mirror::Class> klass) {
	return LookupByDescriptor(klass) == klass;
	}

	ObjPtr<mirror::Class> ClassTable::LookupByDescriptor(ObjPtr<mirror::Class> klass) {
	ReaderMutexLock mu(Thread::Current(), lock_);
	TableSlot slot(klass);
	for (ClassSet& class_set : classes_) {
	auto it = class_set.find(slot);
	if (it != class_set.end()) {
	return it->Read();
	}
	}
	return nullptr;
	}

	ObjPtr<mirror::Class> ClassTable::UpdateClass(const char* descriptor,
	ObjPtr<mirror::Class> klass,
	size_t hash) {
	WriterMutexLock mu(Thread::Current(), lock_);
	// Should only be updating latest table.
	DescriptorHashPair pair(descriptor, hash);
	auto existing_it = classes_.back().FindWithHash(pair, hash);
	if (kIsDebugBuild && existing_it == classes_.back().end()) {
	for (const ClassSet& class_set : classes_) {
	if (class_set.FindWithHash(pair, hash) != class_set.end()) {
	LOG(FATAL) << "Updating class found in frozen table " << descriptor;
	}
	}
	LOG(FATAL) << "Updating class not found " << descriptor;
	}
	const ObjPtr<mirror::Class> existing = existing_it->Read();
	CHECK_NE(existing, klass) << descriptor;
	CHECK(!existing->IsResolved()) << descriptor;
	CHECK_EQ(klass->GetStatus(), ClassStatus::kResolving) << descriptor;
	CHECK(!klass->IsTemp()) << descriptor;
	VerifyObject(klass);
	// Update the element in the hash set with the new class. This is safe to do since the descriptor
	// doesn't change.
	*existing_it = TableSlot(klass, hash);
	return existing;
	}

	size_t ClassTable::CountDefiningLoaderClasses(ObjPtr<mirror::ClassLoader> defining_loader,
	const ClassSet& set) const {
	size_t count = 0;
	for (const TableSlot& root : set) {
	if (root.Read()->GetClassLoader() == defining_loader) {
	++count;
	}
	}
	return count;
	}

	size_t ClassTable::NumZygoteClasses(ObjPtr<mirror::ClassLoader> defining_loader) const {
	ReaderMutexLock mu(Thread::Current(), lock_);
	size_t sum = 0;
	for (size_t i = 0; i < classes_.size() - 1; ++i) {
	sum += CountDefiningLoaderClasses(defining_loader, classes_[i]);
	}
	return sum;
	}

	size_t ClassTable::NumNonZygoteClasses(ObjPtr<mirror::ClassLoader> defining_loader) const {
	ReaderMutexLock mu(Thread::Current(), lock_);
	return CountDefiningLoaderClasses(defining_loader, classes_.back());
	}

	size_t ClassTable::NumReferencedZygoteClasses() const {
	ReaderMutexLock mu(Thread::Current(), lock_);
	size_t sum = 0;
	for (size_t i = 0; i < classes_.size() - 1; ++i) {
	sum += classes_[i].size();
	}
	return sum;
	}

	size_t ClassTable::NumReferencedNonZygoteClasses() const {
	ReaderMutexLock mu(Thread::Current(), lock_);
	return classes_.back().size();
	}

	ObjPtr<mirror::Class> ClassTable::Lookup(const char* descriptor, size_t hash) {
	DescriptorHashPair pair(descriptor, hash);
	ReaderMutexLock mu(Thread::Current(), lock_);
	for (ClassSet& class_set : classes_) {
	auto it = class_set.FindWithHash(pair, hash);
	if (it != class_set.end()) {
	return it->Read();
	}
	}
	return nullptr;
	}

	ObjPtr<mirror::Class> ClassTable::TryInsert(ObjPtr<mirror::Class> klass) {
	TableSlot slot(klass);
	WriterMutexLock mu(Thread::Current(), lock_);
	for (ClassSet& class_set : classes_) {
	auto it = class_set.find(slot);
	if (it != class_set.end()) {
	return it->Read();
	}
	}
	classes_.back().insert(slot);
	return klass;
	}

	void ClassTable::Insert(ObjPtr<mirror::Class> klass) {
	const uint32_t hash = TableSlot::HashDescriptor(klass);
	WriterMutexLock mu(Thread::Current(), lock_);
	classes_.back().InsertWithHash(TableSlot(klass, hash), hash);
	}

	void ClassTable::CopyWithoutLocks(const ClassTable& source_table) {
	if (kIsDebugBuild) {
	for (ClassSet& class_set : classes_) {
	CHECK(class_set.empty());
	}
	}
	for (const ClassSet& class_set : source_table.classes_) {
	for (const TableSlot& slot : class_set) {
	classes_.back().insert(slot);
	}
	}
	}

	void ClassTable::InsertWithoutLocks(ObjPtr<mirror::Class> klass) {
	const uint32_t hash = TableSlot::HashDescriptor(klass);
	classes_.back().InsertWithHash(TableSlot(klass, hash), hash);
	}

	void ClassTable::InsertWithHash(ObjPtr<mirror::Class> klass, size_t hash) {
	WriterMutexLock mu(Thread::Current(), lock_);
	classes_.back().InsertWithHash(TableSlot(klass, hash), hash);
	}

	bool ClassTable::Remove(const char* descriptor) {
	DescriptorHashPair pair(descriptor, ComputeModifiedUtf8Hash(descriptor));
	WriterMutexLock mu(Thread::Current(), lock_);
	for (ClassSet& class_set : classes_) {
	auto it = class_set.find(pair);
	if (it != class_set.end()) {
	class_set.erase(it);
	return true;
	}
	}
	return false;
	}

	uint32_t ClassTable::ClassDescriptorHashEquals::operator()(const TableSlot& slot)
	const {
	std::string temp;
	// No read barrier needed, we're reading a chain of constant references for comparison
	// with null and retrieval of constant primitive data. See ReadBarrierOption.
	return ComputeModifiedUtf8Hash(slot.Read<kWithoutReadBarrier>()->GetDescriptor(&temp));
	}

	bool ClassTable::ClassDescriptorHashEquals::operator()(const TableSlot& a,
	const TableSlot& b) const {
	// No read barrier needed, we're reading a chain of constant references for comparison
	// with null and retrieval of constant primitive data. See ReadBarrierOption.
	if (a.Hash() != b.Hash()) {
	std::string temp;
	DCHECK(!a.Read<kWithoutReadBarrier>()->DescriptorEquals(
	b.Read<kWithoutReadBarrier>()->GetDescriptor(&temp)));
	return false;
	}
	std::string temp;
	return a.Read<kWithoutReadBarrier>()->DescriptorEquals(
	b.Read<kWithoutReadBarrier>()->GetDescriptor(&temp));
	}

	bool ClassTable::ClassDescriptorHashEquals::operator()(const TableSlot& a,
	const DescriptorHashPair& b) const {
	// No read barrier needed, we're reading a chain of constant references for comparison
	// with null and retrieval of constant primitive data. See ReadBarrierOption.
	if (!a.MaskedHashEquals(b.second)) {
	DCHECK(!a.Read<kWithoutReadBarrier>()->DescriptorEquals(b.first));
	return false;
	}
	return a.Read<kWithoutReadBarrier>()->DescriptorEquals(b.first);
	}

	uint32_t ClassTable::ClassDescriptorHashEquals::operator()(const DescriptorHashPair& pair) const {
	return ComputeModifiedUtf8Hash(pair.first);
	}

	bool ClassTable::InsertStrongRoot(ObjPtr<mirror::Object> obj) {
	WriterMutexLock mu(Thread::Current(), lock_);
	DCHECK(obj != nullptr);
	for (GcRoot<mirror::Object>& root : strong_roots_) {
	if (root.Read() == obj) {
	return false;
	}
	}
	strong_roots_.push_back(GcRoot<mirror::Object>(obj));
	// If `obj` is a dex cache associated with a new oat file with GC roots, add it to oat_files_.
	if (obj->IsDexCache()) {
	const DexFile* dex_file = ObjPtr<mirror::DexCache>::DownCast(obj)->GetDexFile();
	if (dex_file != nullptr && dex_file->GetOatDexFile() != nullptr) {
	const OatFile* oat_file = dex_file->GetOatDexFile()->GetOatFile();
	if (oat_file != nullptr && !oat_file->GetBssGcRoots().empty()) {
	InsertOatFileLocked(oat_file); // Ignore return value.
	}
	}
	}
	return true;
	}

	bool ClassTable::InsertOatFile(const OatFile* oat_file) {
	WriterMutexLock mu(Thread::Current(), lock_);
	return InsertOatFileLocked(oat_file);
	}

	bool ClassTable::InsertOatFileLocked(const OatFile* oat_file) {
	if (ContainsElement(oat_files_, oat_file)) {
	return false;
	}
	oat_files_.push_back(oat_file);
	return true;
	}

	size_t ClassTable::WriteToMemory(uint8_t* ptr) const {
	ReaderMutexLock mu(Thread::Current(), lock_);
	ClassSet combined;
	// Combine all the class sets in case there are multiple, also adjusts load factor back to
	// default in case classes were pruned.
	for (const ClassSet& class_set : classes_) {
	for (const TableSlot& root : class_set) {
	combined.insert(root);
	}
	}
	const size_t ret = combined.WriteToMemory(ptr);
	// Sanity check.
	if (kIsDebugBuild && ptr != nullptr) {
	size_t read_count;
	ClassSet class_set(ptr, /make copy/false, &read_count);
	class_set.Verify();
	}
	return ret;
	}

	size_t ClassTable::ReadFromMemory(uint8_t* ptr) {
	size_t read_count = 0;
	AddClassSet(ClassSet(ptr, /make copy/false, &read_count));
	return read_count;
	}

	void ClassTable::AddClassSet(ClassSet&& set) {
	WriterMutexLock mu(Thread::Current(), lock_);
	classes_.insert(classes_.begin(), std::move(set));
	}

	void ClassTable::ClearStrongRoots() {
	WriterMutexLock mu(Thread::Current(), lock_);
	oat_files_.clear();
	strong_roots_.clear();
	}

	ClassTable::TableSlot::TableSlot(ObjPtr<mirror::Class> klass)
	: TableSlot(klass, HashDescriptor(klass)) {}

	uint32_t ClassTable::TableSlot::HashDescriptor(ObjPtr<mirror::Class> klass) {
	std::string temp;
	return ComputeModifiedUtf8Hash(klass->GetDescriptor(&temp));
	}

	} // namespace art