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/*
* Copyright (C) 2017 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_LIBDEXFILE_DEX_DEX_FILE_LAYOUT_H_
#define ART_LIBDEXFILE_DEX_DEX_FILE_LAYOUT_H_
#include <algorithm>
#include <cstdint>
#include <iosfwd>
#include <android-base/logging.h>
namespace art {
class DexFile;
enum class LayoutType : uint8_t {
// Layout of things that are hot (commonly accessed), these should be pinned or madvised will
// need.
kLayoutTypeHot,
// Layout of things that are randomly used. These should be advised to random access.
// Without layout, this is the default mode when loading a dex file.
kLayoutTypeSometimesUsed,
// Layout of things that are only used during startup, these can be madvised after launch.
kLayoutTypeStartupOnly,
// Layout of things that are needed probably only once (class initializers). These can be
// madvised during trim events.
kLayoutTypeUsedOnce,
// Layout of things that are thought to be unused. These things should be advised to random
// access.
kLayoutTypeUnused,
// Unused value, just the number of elements in the enum.
kLayoutTypeCount,
};
std::ostream& operator<<(std::ostream& os, LayoutType collector_type);
// Return the "best" layout option if the same item has multiple different layouts.
static inline LayoutType MergeLayoutType(LayoutType a, LayoutType b) {
return std::min(a, b);
}
enum class MadviseState : uint8_t {
// Madvise based on a file that was just loaded.
kMadviseStateAtLoad,
// Madvise based after launch is finished.
kMadviseStateFinishedLaunch,
// Trim by madvising code that is unlikely to be too important in the future.
kMadviseStateFinishedTrim,
};
std::ostream& operator<<(std::ostream& os, MadviseState collector_type);
// A dex layout section such as code items or strings. Each section is composed of subsections
// that are laid out adjacently to each other such as (hot, unused, startup, etc...).
class DexLayoutSection {
public:
// A subsection is a a continuous range of dex file that is all part of the same layout hint.
class Subsection {
public:
// Use uint32_t to handle 32/64 bit cross compilation.
uint32_t start_offset_ = 0u;
uint32_t end_offset_ = 0u;
bool Contains(uint32_t offset) const {
return start_offset_ <= offset && offset < end_offset_;
}
bool Size() const {
DCHECK_LE(start_offset_, end_offset_);
return end_offset_ - start_offset_;
}
void CombineSection(uint32_t start_offset, uint32_t end_offset) {
DCHECK_LE(start_offset, end_offset);
if (start_offset_ == end_offset_) {
start_offset_ = start_offset;
end_offset_ = end_offset;
} else {
start_offset_ = std::min(start_offset_, start_offset);
end_offset_ = std::max(end_offset_, end_offset);
}
}
void Madvise(const DexFile* dex_file, int advice) const;
};
// Madvise the largest page-aligned region contained in [begin, end).
static int MadviseLargestPageAlignedRegion(const uint8_t* begin, const uint8_t* end, int advice);
Subsection parts_[static_cast<size_t>(LayoutType::kLayoutTypeCount)];
};
// A set of dex layout sections, currently there is only one section for code and one for strings.
class DexLayoutSections {
public:
enum class SectionType : uint8_t {
kSectionTypeCode,
kSectionTypeStrings,
kSectionCount,
};
// Advise access about the dex file based on layout. The caller is expected to have already
// madvised to MADV_RANDOM.
void Madvise(const DexFile* dex_file, MadviseState state) const;
DexLayoutSection sections_[static_cast<size_t>(SectionType::kSectionCount)];
};
std::ostream& operator<<(std::ostream& os, DexLayoutSections::SectionType collector_type);
std::ostream& operator<<(std::ostream& os, const DexLayoutSection& section);
std::ostream& operator<<(std::ostream& os, const DexLayoutSections& sections);
} // namespace art
#endif // ART_LIBDEXFILE_DEX_DEX_FILE_LAYOUT_H_
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