runtime/jit/profile_compilation_info.h - 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.
  */

 #ifndef ART_RUNTIME_JIT_PROFILE_COMPILATION_INFO_H_
 #define ART_RUNTIME_JIT_PROFILE_COMPILATION_INFO_H_

 #include <memory>
 #include <set>
 #include <vector>

 #include "atomic.h"
 #include "dex_cache_resolved_classes.h"
 #include "dex_file.h"
 #include "dex_file_types.h"
 #include "method_reference.h"
 #include "safe_map.h"

 namespace art {

 /**
  *  Convenient class to pass around profile information (including inline caches)
  *  without the need to hold GC-able objects.
  */
 struct ProfileMethodInfo {
   struct ProfileClassReference {
     ProfileClassReference(const DexFile* dex, const dex::TypeIndex& index)
         : dex_file(dex), type_index(index) {}

     const DexFile* dex_file;
     const dex::TypeIndex type_index;
   };

   struct ProfileInlineCache {
     ProfileInlineCache(uint32_t pc, const std::vector<ProfileClassReference>& profile_classes)
         : dex_pc(pc), classes(profile_classes) {}

     const uint32_t dex_pc;
     const std::vector<ProfileClassReference> classes;
   };

   ProfileMethodInfo(const DexFile* dex, uint32_t method_index)
       : dex_file(dex), dex_method_index(method_index) {}

   ProfileMethodInfo(const DexFile* dex,
                     uint32_t method_index,
                     const std::vector<ProfileInlineCache>& caches)
       : dex_file(dex), dex_method_index(method_index), inline_caches(caches) {}

   const DexFile* dex_file;
   const uint32_t dex_method_index;
   const std::vector<ProfileInlineCache> inline_caches;
 };

 /**
  * Profile information in a format suitable to be queried by the compiler and
  * performing profile guided compilation.
  * It is a serialize-friendly format based on information collected by the
  * interpreter (ProfileInfo).
  * Currently it stores only the hot compiled methods.
  */
 class ProfileCompilationInfo {
  public:
   static const uint8_t kProfileMagic[];
   static const uint8_t kProfileVersion[];

   // Data structures for encoding the offline representation of inline caches.
   // This is exposed as public in order to make it available to dex2oat compilations
   // (see compiler/optimizing/inliner.cc).

   // A dex location together with its checksum.
   struct DexReference {
     DexReference() {}

     DexReference(const std::string& location, uint32_t checksum)
         : dex_location(location), dex_checksum(checksum) {}

     bool operator==(const DexReference& other) const {
       return dex_checksum == other.dex_checksum && dex_location == other.dex_location;
     }

     std::string dex_location;
     uint32_t dex_checksum;
   };

   // Encodes a class reference in the profile.
   // The owning dex file is encoded as the index (dex_profile_index) it has in the
   // profile rather than as a full DexRefence(location,checksum).
   // This avoids excessive string copying when managing the profile data.
   // The dex_profile_index is an index in either of:
   //  - OfflineProfileMethodInfo#dex_references vector (public use)
   //  - DexFileData#profile_index (internal use).
   // Note that the dex_profile_index is not necessary the multidex index.
   // We cannot rely on the actual multidex index because a single profile may store
   // data from multiple splits. This means that a profile may contain a classes2.dex from split-A
   // and one from split-B.
   struct ClassReference {
     ClassReference(uint8_t dex_profile_idx, const dex::TypeIndex& type_idx) :
       dex_profile_index(dex_profile_idx), type_index(type_idx) {}

     bool operator==(const ClassReference& other) const {
       return dex_profile_index == other.dex_profile_index && type_index == other.type_index;
     }
     bool operator<(const ClassReference& other) const {
       return dex_profile_index == other.dex_profile_index
           ? type_index < other.type_index
           : dex_profile_index < other.dex_profile_index;
     }

     uint8_t dex_profile_index;  // the index of the owning dex in the profile info
     dex::TypeIndex type_index;  // the type index of the class
   };

   // The set of classes that can be found at a given dex pc.
   using ClassSet = std::set<ClassReference>;

   // Encodes the actual inline cache for a given dex pc (whether or not the receiver is
   // megamorphic and its possible types).
   // If the receiver is megamorphic the set of classes will be empty.
   struct DexPcData {
     DexPcData() : is_megamorphic(false) {}
     void AddClass(uint16_t dex_profile_idx, const dex::TypeIndex& type_idx);
     void SetMegamorphic() {
       is_megamorphic = true;
       classes.clear();
     }
     bool operator==(const DexPcData& other) const {
       return is_megamorphic == other.is_megamorphic && classes == other.classes;
     }

     bool is_megamorphic;
     ClassSet classes;
   };

   // The inline cache map: DexPc -> DexPcData.
   using InlineCacheMap = SafeMap<uint16_t, DexPcData>;

   // Encodes the full set of inline caches for a given method.
   // The dex_references vector is indexed according to the ClassReference::dex_profile_index.
   // i.e. the dex file of any ClassReference present in the inline caches can be found at
   // dex_references[ClassReference::dex_profile_index].
   struct OfflineProfileMethodInfo {
     bool operator==(const OfflineProfileMethodInfo& other) const;

     std::vector<DexReference> dex_references;
     InlineCacheMap inline_caches;
   };

   // Public methods to create, extend or query the profile.

   // Add the given methods and classes to the current profile object.
   bool AddMethodsAndClasses(const std::vector<ProfileMethodInfo>& methods,
                             const std::set<DexCacheResolvedClasses>& resolved_classes);

   // Load profile information from the given file descriptor.
   bool Load(int fd);

   // Merge the data from another ProfileCompilationInfo into the current object.
   bool MergeWith(const ProfileCompilationInfo& info);

   // Save the profile data to the given file descriptor.
   bool Save(int fd);

   // Load and merge profile information from the given file into the current
   // object and tries to save it back to disk.
   // If `force` is true then the save will go through even if the given file
   // has bad data or its version does not match. In this cases the profile content
   // is ignored.
   bool MergeAndSave(const std::string& filename, uint64_t* bytes_written, bool force);

   // Return the number of methods that were profiled.
   uint32_t GetNumberOfMethods() const;

   // Return the number of resolved classes that were profiled.
   uint32_t GetNumberOfResolvedClasses() const;

   // Return true if the method reference is present in the profiling info.
   bool ContainsMethod(const MethodReference& method_ref) const;

   // Return true if the class's type is present in the profiling info.
   bool ContainsClass(const DexFile& dex_file, dex::TypeIndex type_idx) const;

   // Return true if the method is present in the profiling info.
   // If the method is found, `pmi` is populated with its inline caches.
   bool GetMethod(const std::string& dex_location,
                  uint32_t dex_checksum,
                  uint16_t dex_method_index,
                  /*out*/OfflineProfileMethodInfo* pmi) const;

   // Dump all the loaded profile info into a string and returns it.
   // If dex_files is not null then the method indices will be resolved to their
   // names.
   // This is intended for testing and debugging.
   std::string DumpInfo(const std::vector<std::unique_ptr<const DexFile>>* dex_files,
                        bool print_full_dex_location = true) const;
   std::string DumpInfo(const std::vector<const DexFile*>* dex_files,
                        bool print_full_dex_location = true) const;

   void GetClassNames(const std::vector<std::unique_ptr<const DexFile>>* dex_files,
                      std::set<std::string>* class_names) const;

   void GetClassNames(const std::vector<const DexFile*>* dex_files,
                      std::set<std::string>* class_names) const;

   // Perform an equality test with the `other` profile information.
   bool Equals(const ProfileCompilationInfo& other);

   // Return the class descriptors for all of the classes in the profiles' class sets.
   // Note the dex location is actually the profile key, the caller needs to call back in to the
   // profile info stuff to generate a map back to the dex location.
   std::set<DexCacheResolvedClasses> GetResolvedClasses() const;

   // Clear the resolved classes from the current object.
   void ClearResolvedClasses();

   // Return the profile key associated with the given dex location.
   static std::string GetProfileDexFileKey(const std::string& dex_location);

   // Generate a test profile which will contain a percentage of the total maximum
   // number of methods and classes (method_ratio and class_ratio).
   static bool GenerateTestProfile(int fd,
                                   uint16_t number_of_dex_files,
                                   uint16_t method_ratio,
                                   uint16_t class_ratio);

   // Check that the given profile method info contain the same data.
   static bool Equals(const ProfileCompilationInfo::OfflineProfileMethodInfo& pmi1,
                      const ProfileCompilationInfo::OfflineProfileMethodInfo& pmi2);

  private:
   enum ProfileLoadSatus {
     kProfileLoadIOError,
     kProfileLoadVersionMismatch,
     kProfileLoadBadData,
     kProfileLoadSuccess
   };

   // Maps a method dex index to its inline cache.
   using MethodMap = SafeMap<uint16_t, InlineCacheMap>;

   // Internal representation of the profile information belonging to a dex file.
   struct DexFileData {
     DexFileData(uint32_t location_checksum, uint16_t index)
          : profile_index(index), checksum(location_checksum) {}
     // The profile index of this dex file (matches ClassReference#dex_profile_index)
     uint8_t profile_index;
     // The dex checksum
     uint32_t checksum;
     // The methonds' profile information
     MethodMap method_map;
     // The classes which have been profiled. Note that these don't necessarily include
     // all the classes that can be found in the inline caches reference.
     std::set<dex::TypeIndex> class_set;

     bool operator==(const DexFileData& other) const {
       return checksum == other.checksum && method_map == other.method_map;
     }
   };

   // Maps dex file to their profile information.
   using DexFileToProfileInfoMap = SafeMap<const std::string, DexFileData>;

   // Return the profile data for the given dex location or null if the dex location
   // already exists but has a different checksum
   DexFileData* GetOrAddDexFileData(const std::string& dex_location, uint32_t checksum);

   // Add a method index to the profile (without inline caches).
   bool AddMethodIndex(const std::string& dex_location, uint32_t checksum, uint16_t method_idx);

   // Add a method to the profile using its online representation (containing runtime structures).
   bool AddMethod(const ProfileMethodInfo& pmi);

   // Add a method to the profile using its offline representation.
   // This is mostly used to facilitate testing.
   bool AddMethod(const std::string& dex_location,
                  uint32_t dex_checksum,
                  uint16_t method_index,
                  const OfflineProfileMethodInfo& pmi);

   // Add a class index to the profile.
   bool AddClassIndex(const std::string& dex_location, uint32_t checksum, dex::TypeIndex type_idx);

   // Add all classes from the given dex cache to the the profile.
   bool AddResolvedClasses(const DexCacheResolvedClasses& classes);

   // Search for the given method in the profile.
   // If found, its inline cache map is returned, otherwise the method returns null.
   const InlineCacheMap* FindMethod(const std::string& dex_location,
                                    uint32_t dex_checksum,
                                    uint16_t dex_method_index) const;

   // Encode the known dex_files into a vector. The index of a dex_reference will
   // be the same as the profile index of the dex file (used to encode the ClassReferences).
   void DexFileToProfileIndex(/*out*/std::vector<DexReference>* dex_references) const;

   // Parsing functionality.

   // The information present in the header of each profile line.
   struct ProfileLineHeader {
     std::string dex_location;
     uint16_t class_set_size;
     uint32_t method_region_size_bytes;
     uint32_t checksum;
   };

   // A helper structure to make sure we don't read past our buffers in the loops.
   struct SafeBuffer {
    public:
     explicit SafeBuffer(size_t size) : storage_(new uint8_t[size]) {
       ptr_current_ = storage_.get();
       ptr_end_ = ptr_current_ + size;
     }

     // Reads the content of the descriptor at the current position.
     ProfileLoadSatus FillFromFd(int fd,
                                 const std::string& source,
                                 /*out*/std::string* error);

     // Reads an uint value (high bits to low bits) and advances the current pointer
     // with the number of bits read.
     template <typename T> bool ReadUintAndAdvance(/*out*/ T* value);

     // Compares the given data with the content current pointer. If the contents are
     // equal it advances the current pointer by data_size.
     bool CompareAndAdvance(const uint8_t* data, size_t data_size);

     // Returns true if the buffer has more data to read.
     bool HasMoreData();

     // Get the underlying raw buffer.
     uint8_t* Get() { return storage_.get(); }

    private:
     std::unique_ptr<uint8_t[]> storage_;
     uint8_t* ptr_current_;
     uint8_t* ptr_end_;
   };

   // Entry point for profile loding functionality.
   ProfileLoadSatus LoadInternal(int fd, std::string* error);

   // Read the profile header from the given fd and store the number of profile
   // lines into number_of_dex_files.
   ProfileLoadSatus ReadProfileHeader(int fd,
                                      /*out*/uint8_t* number_of_dex_files,
                                      /*out*/std::string* error);

   // Read the header of a profile line from the given fd.
   ProfileLoadSatus ReadProfileLineHeader(int fd,
                                          /*out*/ProfileLineHeader* line_header,
                                          /*out*/std::string* error);

   // Read individual elements from the profile line header.
   bool ReadProfileLineHeaderElements(SafeBuffer& buffer,
                                      /*out*/uint16_t* dex_location_size,
                                      /*out*/ProfileLineHeader* line_header,
                                      /*out*/std::string* error);

   // Read a single profile line from the given fd.
   ProfileLoadSatus ReadProfileLine(int fd,
                                    uint8_t number_of_dex_files,
                                    const ProfileLineHeader& line_header,
                                    /*out*/std::string* error);

   // Read all the classes from the buffer into the profile `info_` structure.
   bool ReadClasses(SafeBuffer& buffer,
                    uint16_t classes_to_read,
                    const ProfileLineHeader& line_header,
                    /*out*/std::string* error);

   // Read all the methods from the buffer into the profile `info_` structure.
   bool ReadMethods(SafeBuffer& buffer,
                    uint8_t number_of_dex_files,
                    const ProfileLineHeader& line_header,
                    /*out*/std::string* error);

   // Read the inline cache encoding from line_bufer into inline_cache.
   bool ReadInlineCache(SafeBuffer& buffer,
                        uint8_t number_of_dex_files,
                        /*out*/InlineCacheMap* inline_cache,
                        /*out*/std::string* error);

   // Encode the inline cache into the given buffer.
   void AddInlineCacheToBuffer(std::vector<uint8_t>* buffer,
                               const InlineCacheMap& inline_cache);

   // Return the number of bytes needed to encode the profile information
   // for the methods in dex_data.
   uint32_t GetMethodsRegionSize(const DexFileData& dex_data);

   // Group `classes` by their owning dex profile index and put the result in
   // `dex_to_classes_map`.
   void GroupClassesByDex(
       const ClassSet& classes,
       /*out*/SafeMap<uint8_t, std::vector<dex::TypeIndex>>* dex_to_classes_map);

   friend class ProfileCompilationInfoTest;
   friend class CompilerDriverProfileTest;
   friend class ProfileAssistantTest;
   friend class Dex2oatLayoutTest;

   DexFileToProfileInfoMap info_;
 };

 }  // namespace art

 #endif  // ART_RUNTIME_JIT_PROFILE_COMPILATION_INFO_H_
	/*
	* 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.
	*/

	#ifndef ART_RUNTIME_JIT_PROFILE_COMPILATION_INFO_H_
	#define ART_RUNTIME_JIT_PROFILE_COMPILATION_INFO_H_

	#include <memory>
	#include <set>
	#include <vector>

	#include "atomic.h"
	#include "dex_cache_resolved_classes.h"
	#include "dex_file.h"
	#include "dex_file_types.h"
	#include "method_reference.h"
	#include "safe_map.h"

	namespace art {

	/**
	* Convenient class to pass around profile information (including inline caches)
	* without the need to hold GC-able objects.
	*/
	struct ProfileMethodInfo {
	struct ProfileClassReference {
	ProfileClassReference(const DexFile* dex, const dex::TypeIndex& index)
	: dex_file(dex), type_index(index) {}

	const DexFile* dex_file;
	const dex::TypeIndex type_index;
	};

	struct ProfileInlineCache {
	ProfileInlineCache(uint32_t pc, const std::vector<ProfileClassReference>& profile_classes)
	: dex_pc(pc), classes(profile_classes) {}

	const uint32_t dex_pc;
	const std::vector<ProfileClassReference> classes;
	};

	ProfileMethodInfo(const DexFile* dex, uint32_t method_index)
	: dex_file(dex), dex_method_index(method_index) {}

	ProfileMethodInfo(const DexFile* dex,
	uint32_t method_index,
	const std::vector<ProfileInlineCache>& caches)
	: dex_file(dex), dex_method_index(method_index), inline_caches(caches) {}

	const DexFile* dex_file;
	const uint32_t dex_method_index;
	const std::vector<ProfileInlineCache> inline_caches;
	};

	/**
	* Profile information in a format suitable to be queried by the compiler and
	* performing profile guided compilation.
	* It is a serialize-friendly format based on information collected by the
	* interpreter (ProfileInfo).
	* Currently it stores only the hot compiled methods.
	*/
	class ProfileCompilationInfo {
	public:
	static const uint8_t kProfileMagic[];
	static const uint8_t kProfileVersion[];

	// Data structures for encoding the offline representation of inline caches.
	// This is exposed as public in order to make it available to dex2oat compilations
	// (see compiler/optimizing/inliner.cc).

	// A dex location together with its checksum.
	struct DexReference {
	DexReference() {}

	DexReference(const std::string& location, uint32_t checksum)
	: dex_location(location), dex_checksum(checksum) {}

	bool operator==(const DexReference& other) const {
	return dex_checksum == other.dex_checksum && dex_location == other.dex_location;
	}

	std::string dex_location;
	uint32_t dex_checksum;
	};

	// Encodes a class reference in the profile.
	// The owning dex file is encoded as the index (dex_profile_index) it has in the
	// profile rather than as a full DexRefence(location,checksum).
	// This avoids excessive string copying when managing the profile data.
	// The dex_profile_index is an index in either of:
	// - OfflineProfileMethodInfo#dex_references vector (public use)
	// - DexFileData#profile_index (internal use).
	// Note that the dex_profile_index is not necessary the multidex index.
	// We cannot rely on the actual multidex index because a single profile may store
	// data from multiple splits. This means that a profile may contain a classes2.dex from split-A
	// and one from split-B.
	struct ClassReference {
	ClassReference(uint8_t dex_profile_idx, const dex::TypeIndex& type_idx) :
	dex_profile_index(dex_profile_idx), type_index(type_idx) {}

	bool operator==(const ClassReference& other) const {
	return dex_profile_index == other.dex_profile_index && type_index == other.type_index;
	}
	bool operator<(const ClassReference& other) const {
	return dex_profile_index == other.dex_profile_index
	? type_index < other.type_index
	: dex_profile_index < other.dex_profile_index;
	}

	uint8_t dex_profile_index; // the index of the owning dex in the profile info
	dex::TypeIndex type_index; // the type index of the class
	};

	// The set of classes that can be found at a given dex pc.
	using ClassSet = std::set<ClassReference>;

	// Encodes the actual inline cache for a given dex pc (whether or not the receiver is
	// megamorphic and its possible types).
	// If the receiver is megamorphic the set of classes will be empty.
	struct DexPcData {
	DexPcData() : is_megamorphic(false) {}
	void AddClass(uint16_t dex_profile_idx, const dex::TypeIndex& type_idx);
	void SetMegamorphic() {
	is_megamorphic = true;
	classes.clear();
	}
	bool operator==(const DexPcData& other) const {
	return is_megamorphic == other.is_megamorphic && classes == other.classes;
	}

	bool is_megamorphic;
	ClassSet classes;
	};

	// The inline cache map: DexPc -> DexPcData.
	using InlineCacheMap = SafeMap<uint16_t, DexPcData>;

	// Encodes the full set of inline caches for a given method.
	// The dex_references vector is indexed according to the ClassReference::dex_profile_index.
	// i.e. the dex file of any ClassReference present in the inline caches can be found at
	// dex_references[ClassReference::dex_profile_index].
	struct OfflineProfileMethodInfo {
	bool operator==(const OfflineProfileMethodInfo& other) const;

	std::vector<DexReference> dex_references;
	InlineCacheMap inline_caches;
	};

	// Public methods to create, extend or query the profile.

	// Add the given methods and classes to the current profile object.
	bool AddMethodsAndClasses(const std::vector<ProfileMethodInfo>& methods,
	const std::set<DexCacheResolvedClasses>& resolved_classes);

	// Load profile information from the given file descriptor.
	bool Load(int fd);

	// Merge the data from another ProfileCompilationInfo into the current object.
	bool MergeWith(const ProfileCompilationInfo& info);

	// Save the profile data to the given file descriptor.
	bool Save(int fd);

	// Load and merge profile information from the given file into the current
	// object and tries to save it back to disk.
	// If `force` is true then the save will go through even if the given file
	// has bad data or its version does not match. In this cases the profile content
	// is ignored.
	bool MergeAndSave(const std::string& filename, uint64_t* bytes_written, bool force);

	// Return the number of methods that were profiled.
	uint32_t GetNumberOfMethods() const;

	// Return the number of resolved classes that were profiled.
	uint32_t GetNumberOfResolvedClasses() const;

	// Return true if the method reference is present in the profiling info.
	bool ContainsMethod(const MethodReference& method_ref) const;

	// Return true if the class's type is present in the profiling info.
	bool ContainsClass(const DexFile& dex_file, dex::TypeIndex type_idx) const;

	// Return true if the method is present in the profiling info.
	// If the method is found, `pmi` is populated with its inline caches.
	bool GetMethod(const std::string& dex_location,
	uint32_t dex_checksum,
	uint16_t dex_method_index,
	/out/OfflineProfileMethodInfo* pmi) const;

	// Dump all the loaded profile info into a string and returns it.
	// If dex_files is not null then the method indices will be resolved to their
	// names.
	// This is intended for testing and debugging.
	std::string DumpInfo(const std::vector<std::unique_ptr<const DexFile>>* dex_files,
	bool print_full_dex_location = true) const;
	std::string DumpInfo(const std::vector<const DexFile> dex_files,
	bool print_full_dex_location = true) const;

	void GetClassNames(const std::vector<std::unique_ptr<const DexFile>>* dex_files,
	std::set<std::string>* class_names) const;

	void GetClassNames(const std::vector<const DexFile> dex_files,
	std::set<std::string>* class_names) const;

	// Perform an equality test with the `other` profile information.
	bool Equals(const ProfileCompilationInfo& other);

	// Return the class descriptors for all of the classes in the profiles' class sets.
	// Note the dex location is actually the profile key, the caller needs to call back in to the
	// profile info stuff to generate a map back to the dex location.
	std::set<DexCacheResolvedClasses> GetResolvedClasses() const;

	// Clear the resolved classes from the current object.
	void ClearResolvedClasses();

	// Return the profile key associated with the given dex location.
	static std::string GetProfileDexFileKey(const std::string& dex_location);

	// Generate a test profile which will contain a percentage of the total maximum
	// number of methods and classes (method_ratio and class_ratio).
	static bool GenerateTestProfile(int fd,
	uint16_t number_of_dex_files,
	uint16_t method_ratio,
	uint16_t class_ratio);

	// Check that the given profile method info contain the same data.
	static bool Equals(const ProfileCompilationInfo::OfflineProfileMethodInfo& pmi1,
	const ProfileCompilationInfo::OfflineProfileMethodInfo& pmi2);

	private:
	enum ProfileLoadSatus {
	kProfileLoadIOError,
	kProfileLoadVersionMismatch,
	kProfileLoadBadData,
	kProfileLoadSuccess
	};

	// Maps a method dex index to its inline cache.
	using MethodMap = SafeMap<uint16_t, InlineCacheMap>;

	// Internal representation of the profile information belonging to a dex file.
	struct DexFileData {
	DexFileData(uint32_t location_checksum, uint16_t index)
	: profile_index(index), checksum(location_checksum) {}
	// The profile index of this dex file (matches ClassReference#dex_profile_index)
	uint8_t profile_index;
	// The dex checksum
	uint32_t checksum;
	// The methonds' profile information
	MethodMap method_map;
	// The classes which have been profiled. Note that these don't necessarily include
	// all the classes that can be found in the inline caches reference.
	std::set<dex::TypeIndex> class_set;

	bool operator==(const DexFileData& other) const {
	return checksum == other.checksum && method_map == other.method_map;
	}
	};

	// Maps dex file to their profile information.
	using DexFileToProfileInfoMap = SafeMap<const std::string, DexFileData>;

	// Return the profile data for the given dex location or null if the dex location
	// already exists but has a different checksum
	DexFileData* GetOrAddDexFileData(const std::string& dex_location, uint32_t checksum);

	// Add a method index to the profile (without inline caches).
	bool AddMethodIndex(const std::string& dex_location, uint32_t checksum, uint16_t method_idx);

	// Add a method to the profile using its online representation (containing runtime structures).
	bool AddMethod(const ProfileMethodInfo& pmi);

	// Add a method to the profile using its offline representation.
	// This is mostly used to facilitate testing.
	bool AddMethod(const std::string& dex_location,
	uint32_t dex_checksum,
	uint16_t method_index,
	const OfflineProfileMethodInfo& pmi);

	// Add a class index to the profile.
	bool AddClassIndex(const std::string& dex_location, uint32_t checksum, dex::TypeIndex type_idx);

	// Add all classes from the given dex cache to the the profile.
	bool AddResolvedClasses(const DexCacheResolvedClasses& classes);

	// Search for the given method in the profile.
	// If found, its inline cache map is returned, otherwise the method returns null.
	const InlineCacheMap* FindMethod(const std::string& dex_location,
	uint32_t dex_checksum,
	uint16_t dex_method_index) const;

	// Encode the known dex_files into a vector. The index of a dex_reference will
	// be the same as the profile index of the dex file (used to encode the ClassReferences).
	void DexFileToProfileIndex(/out/std::vector<DexReference>* dex_references) const;

	// Parsing functionality.

	// The information present in the header of each profile line.
	struct ProfileLineHeader {
	std::string dex_location;
	uint16_t class_set_size;
	uint32_t method_region_size_bytes;
	uint32_t checksum;
	};

	// A helper structure to make sure we don't read past our buffers in the loops.
	struct SafeBuffer {
	public:
	explicit SafeBuffer(size_t size) : storage_(new uint8_t[size]) {
	ptr_current_ = storage_.get();
	ptr_end_ = ptr_current_ + size;
	}

	// Reads the content of the descriptor at the current position.
	ProfileLoadSatus FillFromFd(int fd,
	const std::string& source,
	/out/std::string* error);

	// Reads an uint value (high bits to low bits) and advances the current pointer
	// with the number of bits read.
	template <typename T> bool ReadUintAndAdvance(/out/ T* value);

	// Compares the given data with the content current pointer. If the contents are
	// equal it advances the current pointer by data_size.
	bool CompareAndAdvance(const uint8_t* data, size_t data_size);

	// Returns true if the buffer has more data to read.
	bool HasMoreData();

	// Get the underlying raw buffer.
	uint8_t* Get() { return storage_.get(); }

	private:
	std::unique_ptr<uint8_t[]> storage_;
	uint8_t* ptr_current_;
	uint8_t* ptr_end_;
	};

	// Entry point for profile loding functionality.
	ProfileLoadSatus LoadInternal(int fd, std::string* error);

	// Read the profile header from the given fd and store the number of profile
	// lines into number_of_dex_files.
	ProfileLoadSatus ReadProfileHeader(int fd,
	/out/uint8_t* number_of_dex_files,
	/out/std::string* error);

	// Read the header of a profile line from the given fd.
	ProfileLoadSatus ReadProfileLineHeader(int fd,
	/out/ProfileLineHeader* line_header,
	/out/std::string* error);

	// Read individual elements from the profile line header.
	bool ReadProfileLineHeaderElements(SafeBuffer& buffer,
	/out/uint16_t* dex_location_size,
	/out/ProfileLineHeader* line_header,
	/out/std::string* error);

	// Read a single profile line from the given fd.
	ProfileLoadSatus ReadProfileLine(int fd,
	uint8_t number_of_dex_files,
	const ProfileLineHeader& line_header,
	/out/std::string* error);

	// Read all the classes from the buffer into the profile `info_` structure.
	bool ReadClasses(SafeBuffer& buffer,
	uint16_t classes_to_read,
	const ProfileLineHeader& line_header,
	/out/std::string* error);

	// Read all the methods from the buffer into the profile `info_` structure.
	bool ReadMethods(SafeBuffer& buffer,
	uint8_t number_of_dex_files,
	const ProfileLineHeader& line_header,
	/out/std::string* error);

	// Read the inline cache encoding from line_bufer into inline_cache.
	bool ReadInlineCache(SafeBuffer& buffer,
	uint8_t number_of_dex_files,
	/out/InlineCacheMap* inline_cache,
	/out/std::string* error);

	// Encode the inline cache into the given buffer.
	void AddInlineCacheToBuffer(std::vector<uint8_t>* buffer,
	const InlineCacheMap& inline_cache);

	// Return the number of bytes needed to encode the profile information
	// for the methods in dex_data.
	uint32_t GetMethodsRegionSize(const DexFileData& dex_data);

	// Group `classes` by their owning dex profile index and put the result in
	// `dex_to_classes_map`.
	void GroupClassesByDex(
	const ClassSet& classes,
	/out/SafeMap<uint8_t, std::vector<dex::TypeIndex>>* dex_to_classes_map);

	friend class ProfileCompilationInfoTest;
	friend class CompilerDriverProfileTest;
	friend class ProfileAssistantTest;
	friend class Dex2oatLayoutTest;

	DexFileToProfileInfoMap info_;
	};

	} // namespace art

	#endif // ART_RUNTIME_JIT_PROFILE_COMPILATION_INFO_H_