/*
* 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_RUNTIME_MIRROR_STRING_ALLOC_INL_H_
#define ART_RUNTIME_MIRROR_STRING_ALLOC_INL_H_
#include "string-inl.h"
#include "android-base/stringprintf.h"
#include "array.h"
#include "base/bit_utils.h"
#include "class.h"
#include "class_root.h"
#include "gc/heap-inl.h"
#include "obj_ptr.h"
#include "runtime.h"
#include "runtime_globals.h"
#include "thread.h"
namespace art {
namespace mirror {
// Sets string count in the allocation code path to ensure it is guarded by a CAS.
class SetStringCountVisitor {
public:
explicit SetStringCountVisitor(int32_t count) : count_(count) {
}
void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
REQUIRES_SHARED(Locks::mutator_lock_) {
// Avoid AsString as object is not yet in live bitmap or allocation stack.
ObjPtr<String> string = ObjPtr<String>::DownCast(obj);
string->SetCount(count_);
DCHECK(!string->IsCompressed() || kUseStringCompression);
}
private:
const int32_t count_;
};
// Sets string count and value in the allocation code path to ensure it is guarded by a CAS.
class SetStringCountAndBytesVisitor {
public:
SetStringCountAndBytesVisitor(int32_t count, Handle<ByteArray> src_array, int32_t offset,
int32_t high_byte)
: count_(count), src_array_(src_array), offset_(offset), high_byte_(high_byte) {
}
void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
REQUIRES_SHARED(Locks::mutator_lock_) {
// Avoid AsString as object is not yet in live bitmap or allocation stack.
ObjPtr<String> string = ObjPtr<String>::DownCast(obj);
string->SetCount(count_);
DCHECK(!string->IsCompressed() || kUseStringCompression);
int32_t length = String::GetLengthFromCount(count_);
const uint8_t* const src = reinterpret_cast<uint8_t*>(src_array_->GetData()) + offset_;
if (string->IsCompressed()) {
uint8_t* valueCompressed = string->GetValueCompressed();
for (int i = 0; i < length; i++) {
valueCompressed[i] = (src[i] & 0xFF);
}
} else {
uint16_t* value = string->GetValue();
for (int i = 0; i < length; i++) {
value[i] = high_byte_ + (src[i] & 0xFF);
}
}
}
private:
const int32_t count_;
Handle<ByteArray> src_array_;
const int32_t offset_;
const int32_t high_byte_;
};
// Sets string count and value in the allocation code path to ensure it is guarded by a CAS.
class SetStringCountAndValueVisitorFromCharArray {
public:
SetStringCountAndValueVisitorFromCharArray(int32_t count, Handle<CharArray> src_array,
int32_t offset) :
count_(count), src_array_(src_array), offset_(offset) {
}
void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
REQUIRES_SHARED(Locks::mutator_lock_) {
// Avoid AsString as object is not yet in live bitmap or allocation stack.
ObjPtr<String> string = ObjPtr<String>::DownCast(obj);
string->SetCount(count_);
const uint16_t* const src = src_array_->GetData() + offset_;
const int32_t length = String::GetLengthFromCount(count_);
if (kUseStringCompression && String::IsCompressed(count_)) {
for (int i = 0; i < length; ++i) {
string->GetValueCompressed()[i] = static_cast<uint8_t>(src[i]);
}
} else {
memcpy(string->GetValue(), src, length * sizeof(uint16_t));
}
}
private:
const int32_t count_;
Handle<CharArray> src_array_;
const int32_t offset_;
};
// Sets string count and value in the allocation code path to ensure it is guarded by a CAS.
class SetStringCountAndValueVisitorFromString {
public:
SetStringCountAndValueVisitorFromString(int32_t count,
Handle<String> src_string,
int32_t offset) :
count_(count), src_string_(src_string), offset_(offset) {
}
void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
REQUIRES_SHARED(Locks::mutator_lock_) {
// Avoid AsString as object is not yet in live bitmap or allocation stack.
ObjPtr<String> string = ObjPtr<String>::DownCast(obj);
string->SetCount(count_);
const int32_t length = String::GetLengthFromCount(count_);
bool compressible = kUseStringCompression && String::IsCompressed(count_);
if (src_string_->IsCompressed()) {
const uint8_t* const src = src_string_->GetValueCompressed() + offset_;
memcpy(string->GetValueCompressed(), src, length * sizeof(uint8_t));
} else {
const uint16_t* const src = src_string_->GetValue() + offset_;
if (compressible) {
for (int i = 0; i < length; ++i) {
string->GetValueCompressed()[i] = static_cast<uint8_t>(src[i]);
}
} else {
memcpy(string->GetValue(), src, length * sizeof(uint16_t));
}
}
}
private:
const int32_t count_;
Handle<String> src_string_;
const int32_t offset_;
};
template <bool kIsInstrumented, typename PreFenceVisitor>
inline ObjPtr<String> String::Alloc(Thread* self,
int32_t utf16_length_with_flag,
gc::AllocatorType allocator_type,
const PreFenceVisitor& pre_fence_visitor) {
constexpr size_t header_size = sizeof(String);
const bool compressible = kUseStringCompression && String::IsCompressed(utf16_length_with_flag);
const size_t block_size = (compressible) ? sizeof(uint8_t) : sizeof(uint16_t);
size_t length = String::GetLengthFromCount(utf16_length_with_flag);
static_assert(sizeof(length) <= sizeof(size_t),
"static_cast<size_t>(utf16_length) must not lose bits.");
size_t data_size = block_size * length;
size_t size = header_size + data_size;
// String.equals() intrinsics assume zero-padding up to kObjectAlignment,
// so make sure the allocator clears the padding as well.
// http://b/23528461
size_t alloc_size = RoundUp(size, kObjectAlignment);
Runtime* runtime = Runtime::Current();
ObjPtr<Class> string_class = GetClassRoot<String>(runtime->GetClassLinker());
// Check for overflow and throw OutOfMemoryError if this was an unreasonable request.
// Do this by comparing with the maximum length that will _not_ cause an overflow.
const size_t overflow_length = (-header_size) / block_size; // Unsigned arithmetic.
const size_t max_alloc_length = overflow_length - 1u;
static_assert(IsAligned<sizeof(uint16_t)>(kObjectAlignment),
"kObjectAlignment must be at least as big as Java char alignment");
const size_t max_length = RoundDown(max_alloc_length, kObjectAlignment / block_size);
if (UNLIKELY(length > max_length)) {
self->ThrowOutOfMemoryError(
android::base::StringPrintf("%s of length %d would overflow",
Class::PrettyDescriptor(string_class).c_str(),
static_cast<int>(length)).c_str());
return nullptr;
}
gc::Heap* heap = runtime->GetHeap();
return ObjPtr<String>::DownCast(
heap->AllocObjectWithAllocator<kIsInstrumented, true>(self,
string_class,
alloc_size,
allocator_type,
pre_fence_visitor));
}
template <bool kIsInstrumented>
inline ObjPtr<String> String::AllocEmptyString(Thread* self, gc::AllocatorType allocator_type) {
const int32_t length_with_flag = String::GetFlaggedCount(0, /* compressible= */ true);
SetStringCountVisitor visitor(length_with_flag);
return Alloc<kIsInstrumented>(self, length_with_flag, allocator_type, visitor);
}
template <bool kIsInstrumented>
inline ObjPtr<String> String::AllocFromByteArray(Thread* self,
int32_t byte_length,
Handle<ByteArray> array,
int32_t offset,
int32_t high_byte,
gc::AllocatorType allocator_type) {
const uint8_t* const src = reinterpret_cast<uint8_t*>(array->GetData()) + offset;
high_byte &= 0xff; // Extract the relevant bits before determining `compressible`.
const bool compressible =
kUseStringCompression && String::AllASCII<uint8_t>(src, byte_length) && (high_byte == 0);
const int32_t length_with_flag = String::GetFlaggedCount(byte_length, compressible);
SetStringCountAndBytesVisitor visitor(length_with_flag, array, offset, high_byte << 8);
return Alloc<kIsInstrumented>(self, length_with_flag, allocator_type, visitor);
}
template <bool kIsInstrumented>
inline ObjPtr<String> String::AllocFromCharArray(Thread* self,
int32_t count,
Handle<CharArray> array,
int32_t offset,
gc::AllocatorType allocator_type) {
// It is a caller error to have a count less than the actual array's size.
DCHECK_GE(array->GetLength(), count);
const bool compressible = kUseStringCompression &&
String::AllASCII<uint16_t>(array->GetData() + offset, count);
const int32_t length_with_flag = String::GetFlaggedCount(count, compressible);
SetStringCountAndValueVisitorFromCharArray visitor(length_with_flag, array, offset);
return Alloc<kIsInstrumented>(self, length_with_flag, allocator_type, visitor);
}
template <bool kIsInstrumented>
inline ObjPtr<String> String::AllocFromString(Thread* self,
int32_t string_length,
Handle<String> string,
int32_t offset,
gc::AllocatorType allocator_type) {
const bool compressible = kUseStringCompression &&
((string->IsCompressed()) ? true : String::AllASCII<uint16_t>(string->GetValue() + offset,
string_length));
const int32_t length_with_flag = String::GetFlaggedCount(string_length, compressible);
SetStringCountAndValueVisitorFromString visitor(length_with_flag, string, offset);
return Alloc<kIsInstrumented>(self, length_with_flag, allocator_type, visitor);
}
} // namespace mirror
} // namespace art
#endif // ART_RUNTIME_MIRROR_STRING_ALLOC_INL_H_