simpleperf/dso.cpp - platform/system/extras - Git at Google

 /*
  * 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 "dso.h"

 #include <stdlib.h>
 #include <string.h>

 #include <algorithm>
 #include <limits>
 #include <vector>

 #include <android-base/file.h>
 #include <android-base/logging.h>

 #include "environment.h"
 #include "read_apk.h"
 #include "read_elf.h"
 #include "utils.h"

 static OneTimeFreeAllocator symbol_name_allocator;

 Symbol::Symbol(const std::string& name, uint64_t addr, uint64_t len)
     : addr(addr),
       len(len),
       name_(symbol_name_allocator.AllocateString(name)),
       demangled_name_(nullptr),
       has_dumped_(false) {}

 const char* Symbol::DemangledName() const {
   if (demangled_name_ == nullptr) {
     const std::string s = Dso::Demangle(name_);
     if (s == name_) {
       demangled_name_ = name_;
     } else {
       demangled_name_ = symbol_name_allocator.AllocateString(s);
     }
   }
   return demangled_name_;
 }

 bool Dso::demangle_ = true;
 std::string Dso::symfs_dir_;
 std::string Dso::vmlinux_;
 std::string Dso::kallsyms_;
 std::unordered_map<std::string, BuildId> Dso::build_id_map_;
 size_t Dso::dso_count_;

 void Dso::SetDemangle(bool demangle) { demangle_ = demangle; }

 extern "C" char* __cxa_demangle(const char* mangled_name, char* buf, size_t* n,
                                 int* status);

 std::string Dso::Demangle(const std::string& name) {
   if (!demangle_) {
     return name;
   }
   int status;
   bool is_linker_symbol = (name.find(linker_prefix) == 0);
   const char* mangled_str = name.c_str();
   if (is_linker_symbol) {
     mangled_str += linker_prefix.size();
   }
   std::string result = name;
   char* demangled_name = __cxa_demangle(mangled_str, nullptr, nullptr, &status);
   if (status == 0) {
     if (is_linker_symbol) {
       result = std::string("[linker]") + demangled_name;
     } else {
       result = demangled_name;
     }
     free(demangled_name);
   } else if (is_linker_symbol) {
     result = std::string("[linker]") + mangled_str;
   }
   return result;
 }

 bool Dso::SetSymFsDir(const std::string& symfs_dir) {
   std::string dirname = symfs_dir;
   if (!dirname.empty()) {
     if (dirname.back() != '/') {
       dirname.push_back('/');
     }
     std::vector<std::string> files;
     std::vector<std::string> subdirs;
     GetEntriesInDir(symfs_dir, &files, &subdirs);
     if (files.empty() && subdirs.empty()) {
       LOG(ERROR) << "Invalid symfs_dir '" << symfs_dir << "'";
       return false;
     }
   }
   symfs_dir_ = dirname;
   return true;
 }

 void Dso::SetVmlinux(const std::string& vmlinux) { vmlinux_ = vmlinux; }

 void Dso::SetBuildIds(
     const std::vector<std::pair<std::string, BuildId>>& build_ids) {
   std::unordered_map<std::string, BuildId> map;
   for (auto& pair : build_ids) {
     LOG(DEBUG) << "build_id_map: " << pair.first << ", "
                << pair.second.ToString();
     map.insert(pair);
   }
   build_id_map_ = std::move(map);
 }

 BuildId Dso::GetExpectedBuildId() {
   auto it = build_id_map_.find(path_);
   if (it != build_id_map_.end()) {
     return it->second;
   }
   return BuildId();
 }

 std::unique_ptr<Dso> Dso::CreateDso(DsoType dso_type,
                                     const std::string& dso_path) {
   static uint64_t id = 0;
   return std::unique_ptr<Dso>(new Dso(dso_type, ++id, dso_path));
 }

 Dso::Dso(DsoType type, uint64_t id, const std::string& path)
     : type_(type),
       id_(id),
       path_(path),
       debug_file_path_(path),
       min_vaddr_(std::numeric_limits<uint64_t>::max()),
       is_loaded_(false),
       has_dumped_(false) {
   // Check if file matching path_ exists in symfs directory before using it as
   // debug_file_path_.
   if (!symfs_dir_.empty()) {
     std::string path_in_symfs = symfs_dir_ + path_;
     std::tuple<bool, std::string, std::string> tuple =
         SplitUrlInApk(path_in_symfs);
     std::string file_path =
         std::get<0>(tuple) ? std::get<1>(tuple) : path_in_symfs;
     if (IsRegularFile(file_path)) {
       debug_file_path_ = path_in_symfs;
     }
   }
   size_t pos = path.find_last_of("/\\");
   if (pos != std::string::npos) {
     file_name_ = path.substr(pos + 1);
   } else {
     file_name_ = path;
   }
   dso_count_++;
 }

 Dso::~Dso() {
   if (--dso_count_ == 0) {
     // Clean up global variables when no longer used.
     symbol_name_allocator.Clear();
     demangle_ = true;
     symfs_dir_.clear();
     vmlinux_.clear();
     kallsyms_.clear();
     build_id_map_.clear();
   }
 }

 const Symbol* Dso::FindSymbol(uint64_t vaddr_in_dso) {
   if (!is_loaded_) {
     is_loaded_ = true;
     // If symbols has been read from SymbolRecords, no need to load them from
     // dso.
     if (symbols_.empty()) {
       if (!Load()) {
         LOG(DEBUG) << "failed to load dso: " << path_;
         return nullptr;
       }
     }
   }
   if (symbols_.empty()) {
     return nullptr;
   }

   auto it = symbols_.upper_bound(Symbol("", vaddr_in_dso, 0));
   if (it != symbols_.begin()) {
     --it;
     if (it->addr <= vaddr_in_dso && it->addr + it->len > vaddr_in_dso) {
       return &*it;
     }
   }
   return nullptr;
 }

 uint64_t Dso::MinVirtualAddress() {
   if (min_vaddr_ == std::numeric_limits<uint64_t>::max()) {
     min_vaddr_ = 0;
     if (type_ == DSO_ELF_FILE) {
       BuildId build_id = GetExpectedBuildId();

       uint64_t addr;
       if (ReadMinExecutableVirtualAddressFromElfFile(GetDebugFilePath(),
                                                      build_id, &addr)) {
         min_vaddr_ = addr;
       }
     }
   }
   return min_vaddr_;
 }

 bool Dso::Load() {
   bool result = false;
   switch (type_) {
     case DSO_KERNEL:
       result = LoadKernel();
       break;
     case DSO_KERNEL_MODULE:
       result = LoadKernelModule();
       break;
     case DSO_ELF_FILE: {
       if (std::get<0>(SplitUrlInApk(path_))) {
         result = LoadEmbeddedElfFile();
       } else {
         result = LoadElfFile();
       }
       break;
     }
   }
   if (result) {
     FixupSymbolLength();
   }
   return result;
 }

 static bool IsKernelFunctionSymbol(const KernelSymbol& symbol) {
   return (symbol.type == 'T' || symbol.type == 't' || symbol.type == 'W' ||
           symbol.type == 'w');
 }

 static bool KernelSymbolCallback(const KernelSymbol& kernel_symbol, Dso* dso) {
   if (IsKernelFunctionSymbol(kernel_symbol)) {
     dso->InsertSymbol(Symbol(kernel_symbol.name, kernel_symbol.addr, 0));
   }
   return false;
 }

 static void VmlinuxSymbolCallback(const ElfFileSymbol& elf_symbol, Dso* dso) {
   if (elf_symbol.is_func) {
     dso->InsertSymbol(
         Symbol(elf_symbol.name, elf_symbol.vaddr, elf_symbol.len));
   }
 }

 bool Dso::LoadKernel() {
   BuildId build_id = GetExpectedBuildId();
   if (!vmlinux_.empty()) {
     ParseSymbolsFromElfFile(
         vmlinux_, build_id,
         std::bind(VmlinuxSymbolCallback, std::placeholders::_1, this));
   } else if (!kallsyms_.empty()) {
     ProcessKernelSymbols(kallsyms_, std::bind(&KernelSymbolCallback,
                                               std::placeholders::_1, this));
     bool all_zero = true;
     for (const auto& symbol : symbols_) {
       if (symbol.addr != 0) {
         all_zero = false;
         break;
       }
     }
     if (all_zero) {
       LOG(WARNING)
           << "Symbol addresses in /proc/kallsyms on device are all zero. "
              "`echo 0 >/proc/sys/kernel/kptr_restrict` if possible.";
       symbols_.clear();
       return false;
     }
   } else {
     if (!build_id.IsEmpty()) {
       BuildId real_build_id;
       GetKernelBuildId(&real_build_id);
       bool match = (build_id == real_build_id);
       LOG(WARNING) << "check kernel build id ("
                    << (match ? "match" : "mismatch") << "): expected "
                    << build_id.ToString() << ", real "
                    << real_build_id.ToString();
       if (!match) {
         return false;
       }
     }

     std::string kallsyms;
     if (!android::base::ReadFileToString("/proc/kallsyms", &kallsyms)) {
       LOG(DEBUG) << "failed to read /proc/kallsyms";
       return false;
     }
     ProcessKernelSymbols(kallsyms, std::bind(&KernelSymbolCallback,
                                              std::placeholders::_1, this));
     bool all_zero = true;
     for (const auto& symbol : symbols_) {
       if (symbol.addr != 0) {
         all_zero = false;
         break;
       }
     }
     if (all_zero) {
       LOG(WARNING) << "Symbol addresses in /proc/kallsyms are all zero. "
                       "`echo 0 >/proc/sys/kernel/kptr_restrict` if possible.";
       symbols_.clear();
       return false;
     }
   }
   return true;
 }

 static void ElfFileSymbolCallback(const ElfFileSymbol& elf_symbol, Dso* dso,
                                   bool (*filter)(const ElfFileSymbol&)) {
   if (filter(elf_symbol)) {
     dso->InsertSymbol(
         Symbol(elf_symbol.name, elf_symbol.vaddr, elf_symbol.len));
   }
 }

 static bool SymbolFilterForKernelModule(const ElfFileSymbol& elf_symbol) {
   // TODO: Parse symbol outside of .text section.
   return (elf_symbol.is_func && elf_symbol.is_in_text_section);
 }

 bool Dso::LoadKernelModule() {
   BuildId build_id = GetExpectedBuildId();
   ParseSymbolsFromElfFile(
       symfs_dir_ + path_, build_id,
       std::bind(ElfFileSymbolCallback, std::placeholders::_1, this,
                 SymbolFilterForKernelModule));
   return true;
 }

 static bool SymbolFilterForDso(const ElfFileSymbol& elf_symbol) {
   return elf_symbol.is_func ||
          (elf_symbol.is_label && elf_symbol.is_in_text_section);
 }

 bool Dso::LoadElfFile() {
   bool loaded = false;
   BuildId build_id = GetExpectedBuildId();

   if (symfs_dir_.empty()) {
     // Linux host can store debug shared libraries in /usr/lib/debug.
     loaded = ParseSymbolsFromElfFile(
         "/usr/lib/debug" + path_, build_id,
         std::bind(ElfFileSymbolCallback, std::placeholders::_1, this,
                   SymbolFilterForDso));
   }
   if (!loaded) {
     loaded = ParseSymbolsFromElfFile(
         GetDebugFilePath(), build_id,
         std::bind(ElfFileSymbolCallback, std::placeholders::_1, this,
                   SymbolFilterForDso));
   }
   return loaded;
 }

 bool Dso::LoadEmbeddedElfFile() {
   std::string path = GetDebugFilePath();
   BuildId build_id = GetExpectedBuildId();
   auto tuple = SplitUrlInApk(path);
   CHECK(std::get<0>(tuple));
   return ParseSymbolsFromApkFile(
       std::get<1>(tuple), std::get<2>(tuple), build_id,
       std::bind(ElfFileSymbolCallback, std::placeholders::_1, this,
                 SymbolFilterForDso));
 }

 void Dso::InsertSymbol(const Symbol& symbol) { symbols_.insert(symbol); }

 void Dso::FixupSymbolLength() {
   Symbol* prev_symbol = nullptr;
   for (auto& symbol : symbols_) {
     if (prev_symbol != nullptr && prev_symbol->len == 0) {
       prev_symbol->len = symbol.addr - prev_symbol->addr;
     }
     prev_symbol = const_cast<Symbol*>(&symbol);
   }
   if (prev_symbol != nullptr && prev_symbol->len == 0) {
     prev_symbol->len = std::numeric_limits<uint64_t>::max() - prev_symbol->addr;
   }
 }

 const char* DsoTypeToString(DsoType dso_type) {
   switch (dso_type) {
     case DSO_KERNEL:
       return "dso_kernel";
     case DSO_KERNEL_MODULE:
       return "dso_kernel_module";
     case DSO_ELF_FILE:
       return "dso_elf_file";
     default:
       return "unknown";
   }
 }
	/*
	* 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 "dso.h"

	#include <stdlib.h>
	#include <string.h>

	#include <algorithm>
	#include <limits>
	#include <vector>

	#include <android-base/file.h>
	#include <android-base/logging.h>

	#include "environment.h"
	#include "read_apk.h"
	#include "read_elf.h"
	#include "utils.h"

	static OneTimeFreeAllocator symbol_name_allocator;

	Symbol::Symbol(const std::string& name, uint64_t addr, uint64_t len)
	: addr(addr),
	len(len),
	name_(symbol_name_allocator.AllocateString(name)),
	demangled_name_(nullptr),
	has_dumped_(false) {}

	const char* Symbol::DemangledName() const {
	if (demangled_name_ == nullptr) {
	const std::string s = Dso::Demangle(name_);
	if (s == name_) {
	demangled_name_ = name_;
	} else {
	demangled_name_ = symbol_name_allocator.AllocateString(s);
	}
	}
	return demangled_name_;
	}

	bool Dso::demangle_ = true;
	std::string Dso::symfs_dir_;
	std::string Dso::vmlinux_;
	std::string Dso::kallsyms_;
	std::unordered_map<std::string, BuildId> Dso::build_id_map_;
	size_t Dso::dso_count_;

	void Dso::SetDemangle(bool demangle) { demangle_ = demangle; }

	extern "C" char* __cxa_demangle(const char* mangled_name, char* buf, size_t* n,
	int* status);

	std::string Dso::Demangle(const std::string& name) {
	if (!demangle_) {
	return name;
	}
	int status;
	bool is_linker_symbol = (name.find(linker_prefix) == 0);
	const char* mangled_str = name.c_str();
	if (is_linker_symbol) {
	mangled_str += linker_prefix.size();
	}
	std::string result = name;
	char* demangled_name = __cxa_demangle(mangled_str, nullptr, nullptr, &status);
	if (status == 0) {
	if (is_linker_symbol) {
	result = std::string("[linker]") + demangled_name;
	} else {
	result = demangled_name;
	}
	free(demangled_name);
	} else if (is_linker_symbol) {
	result = std::string("[linker]") + mangled_str;
	}
	return result;
	}

	bool Dso::SetSymFsDir(const std::string& symfs_dir) {
	std::string dirname = symfs_dir;
	if (!dirname.empty()) {
	if (dirname.back() != '/') {
	dirname.push_back('/');
	}
	std::vector<std::string> files;
	std::vector<std::string> subdirs;
	GetEntriesInDir(symfs_dir, &files, &subdirs);
	if (files.empty() && subdirs.empty()) {
	LOG(ERROR) << "Invalid symfs_dir '" << symfs_dir << "'";
	return false;
	}
	}
	symfs_dir_ = dirname;
	return true;
	}

	void Dso::SetVmlinux(const std::string& vmlinux) { vmlinux_ = vmlinux; }

	void Dso::SetBuildIds(
	const std::vector<std::pair<std::string, BuildId>>& build_ids) {
	std::unordered_map<std::string, BuildId> map;
	for (auto& pair : build_ids) {
	LOG(DEBUG) << "build_id_map: " << pair.first << ", "
	<< pair.second.ToString();
	map.insert(pair);
	}
	build_id_map_ = std::move(map);
	}

	BuildId Dso::GetExpectedBuildId() {
	auto it = build_id_map_.find(path_);
	if (it != build_id_map_.end()) {
	return it->second;
	}
	return BuildId();
	}

	std::unique_ptr<Dso> Dso::CreateDso(DsoType dso_type,
	const std::string& dso_path) {
	static uint64_t id = 0;
	return std::unique_ptr<Dso>(new Dso(dso_type, ++id, dso_path));
	}

	Dso::Dso(DsoType type, uint64_t id, const std::string& path)
	: type_(type),
	id_(id),
	path_(path),
	debug_file_path_(path),
	min_vaddr_(std::numeric_limits<uint64_t>::max()),
	is_loaded_(false),
	has_dumped_(false) {
	// Check if file matching path_ exists in symfs directory before using it as
	// debug_file_path_.
	if (!symfs_dir_.empty()) {
	std::string path_in_symfs = symfs_dir_ + path_;
	std::tuple<bool, std::string, std::string> tuple =
	SplitUrlInApk(path_in_symfs);
	std::string file_path =
	std::get<0>(tuple) ? std::get<1>(tuple) : path_in_symfs;
	if (IsRegularFile(file_path)) {
	debug_file_path_ = path_in_symfs;
	}
	}
	size_t pos = path.find_last_of("/\\");
	if (pos != std::string::npos) {
	file_name_ = path.substr(pos + 1);
	} else {
	file_name_ = path;
	}
	dso_count_++;
	}

	Dso::~Dso() {
	if (--dso_count_ == 0) {
	// Clean up global variables when no longer used.
	symbol_name_allocator.Clear();
	demangle_ = true;
	symfs_dir_.clear();
	vmlinux_.clear();
	kallsyms_.clear();
	build_id_map_.clear();
	}
	}

	const Symbol* Dso::FindSymbol(uint64_t vaddr_in_dso) {
	if (!is_loaded_) {
	is_loaded_ = true;
	// If symbols has been read from SymbolRecords, no need to load them from
	// dso.
	if (symbols_.empty()) {
	if (!Load()) {
	LOG(DEBUG) << "failed to load dso: " << path_;
	return nullptr;
	}
	}
	}
	if (symbols_.empty()) {
	return nullptr;
	}

	auto it = symbols_.upper_bound(Symbol("", vaddr_in_dso, 0));
	if (it != symbols_.begin()) {
	--it;
	if (it->addr <= vaddr_in_dso && it->addr + it->len > vaddr_in_dso) {
	return &*it;
	}
	}
	return nullptr;
	}

	uint64_t Dso::MinVirtualAddress() {
	if (min_vaddr_ == std::numeric_limits<uint64_t>::max()) {
	min_vaddr_ = 0;
	if (type_ == DSO_ELF_FILE) {
	BuildId build_id = GetExpectedBuildId();

	uint64_t addr;
	if (ReadMinExecutableVirtualAddressFromElfFile(GetDebugFilePath(),
	build_id, &addr)) {
	min_vaddr_ = addr;
	}
	}
	}
	return min_vaddr_;
	}

	bool Dso::Load() {
	bool result = false;
	switch (type_) {
	case DSO_KERNEL:
	result = LoadKernel();
	break;
	case DSO_KERNEL_MODULE:
	result = LoadKernelModule();
	break;
	case DSO_ELF_FILE: {
	if (std::get<0>(SplitUrlInApk(path_))) {
	result = LoadEmbeddedElfFile();
	} else {
	result = LoadElfFile();
	}
	break;
	}
	}
	if (result) {
	FixupSymbolLength();
	}
	return result;
	}

	static bool IsKernelFunctionSymbol(const KernelSymbol& symbol) {
	return (symbol.type == 'T' \|\| symbol.type == 't' \|\| symbol.type == 'W' \|\|
	symbol.type == 'w');
	}

	static bool KernelSymbolCallback(const KernelSymbol& kernel_symbol, Dso* dso) {
	if (IsKernelFunctionSymbol(kernel_symbol)) {
	dso->InsertSymbol(Symbol(kernel_symbol.name, kernel_symbol.addr, 0));
	}
	return false;
	}

	static void VmlinuxSymbolCallback(const ElfFileSymbol& elf_symbol, Dso* dso) {
	if (elf_symbol.is_func) {
	dso->InsertSymbol(
	Symbol(elf_symbol.name, elf_symbol.vaddr, elf_symbol.len));
	}
	}

	bool Dso::LoadKernel() {
	BuildId build_id = GetExpectedBuildId();
	if (!vmlinux_.empty()) {
	ParseSymbolsFromElfFile(
	vmlinux_, build_id,
	std::bind(VmlinuxSymbolCallback, std::placeholders::_1, this));
	} else if (!kallsyms_.empty()) {
	ProcessKernelSymbols(kallsyms_, std::bind(&KernelSymbolCallback,
	std::placeholders::_1, this));
	bool all_zero = true;
	for (const auto& symbol : symbols_) {
	if (symbol.addr != 0) {
	all_zero = false;
	break;
	}
	}
	if (all_zero) {
	LOG(WARNING)
	<< "Symbol addresses in /proc/kallsyms on device are all zero. "
	"`echo 0 >/proc/sys/kernel/kptr_restrict` if possible.";
	symbols_.clear();
	return false;
	}
	} else {
	if (!build_id.IsEmpty()) {
	BuildId real_build_id;
	GetKernelBuildId(&real_build_id);
	bool match = (build_id == real_build_id);
	LOG(WARNING) << "check kernel build id ("
	<< (match ? "match" : "mismatch") << "): expected "
	<< build_id.ToString() << ", real "
	<< real_build_id.ToString();
	if (!match) {
	return false;
	}
	}

	std::string kallsyms;
	if (!android::base::ReadFileToString("/proc/kallsyms", &kallsyms)) {
	LOG(DEBUG) << "failed to read /proc/kallsyms";
	return false;
	}
	ProcessKernelSymbols(kallsyms, std::bind(&KernelSymbolCallback,
	std::placeholders::_1, this));
	bool all_zero = true;
	for (const auto& symbol : symbols_) {
	if (symbol.addr != 0) {
	all_zero = false;
	break;
	}
	}
	if (all_zero) {
	LOG(WARNING) << "Symbol addresses in /proc/kallsyms are all zero. "
	"`echo 0 >/proc/sys/kernel/kptr_restrict` if possible.";
	symbols_.clear();
	return false;
	}
	}
	return true;
	}

	static void ElfFileSymbolCallback(const ElfFileSymbol& elf_symbol, Dso* dso,
	bool (*filter)(const ElfFileSymbol&)) {
	if (filter(elf_symbol)) {
	dso->InsertSymbol(
	Symbol(elf_symbol.name, elf_symbol.vaddr, elf_symbol.len));
	}
	}

	static bool SymbolFilterForKernelModule(const ElfFileSymbol& elf_symbol) {
	// TODO: Parse symbol outside of .text section.
	return (elf_symbol.is_func && elf_symbol.is_in_text_section);
	}

	bool Dso::LoadKernelModule() {
	BuildId build_id = GetExpectedBuildId();
	ParseSymbolsFromElfFile(
	symfs_dir_ + path_, build_id,
	std::bind(ElfFileSymbolCallback, std::placeholders::_1, this,
	SymbolFilterForKernelModule));
	return true;
	}

	static bool SymbolFilterForDso(const ElfFileSymbol& elf_symbol) {
	return elf_symbol.is_func \|\|
	(elf_symbol.is_label && elf_symbol.is_in_text_section);
	}

	bool Dso::LoadElfFile() {
	bool loaded = false;
	BuildId build_id = GetExpectedBuildId();

	if (symfs_dir_.empty()) {
	// Linux host can store debug shared libraries in /usr/lib/debug.
	loaded = ParseSymbolsFromElfFile(
	"/usr/lib/debug" + path_, build_id,
	std::bind(ElfFileSymbolCallback, std::placeholders::_1, this,
	SymbolFilterForDso));
	}
	if (!loaded) {
	loaded = ParseSymbolsFromElfFile(
	GetDebugFilePath(), build_id,
	std::bind(ElfFileSymbolCallback, std::placeholders::_1, this,
	SymbolFilterForDso));
	}
	return loaded;
	}

	bool Dso::LoadEmbeddedElfFile() {
	std::string path = GetDebugFilePath();
	BuildId build_id = GetExpectedBuildId();
	auto tuple = SplitUrlInApk(path);
	CHECK(std::get<0>(tuple));
	return ParseSymbolsFromApkFile(
	std::get<1>(tuple), std::get<2>(tuple), build_id,
	std::bind(ElfFileSymbolCallback, std::placeholders::_1, this,
	SymbolFilterForDso));
	}

	void Dso::InsertSymbol(const Symbol& symbol) { symbols_.insert(symbol); }

	void Dso::FixupSymbolLength() {
	Symbol* prev_symbol = nullptr;
	for (auto& symbol : symbols_) {
	if (prev_symbol != nullptr && prev_symbol->len == 0) {
	prev_symbol->len = symbol.addr - prev_symbol->addr;
	}
	prev_symbol = const_cast<Symbol*>(&symbol);
	}
	if (prev_symbol != nullptr && prev_symbol->len == 0) {
	prev_symbol->len = std::numeric_limits<uint64_t>::max() - prev_symbol->addr;
	}
	}

	const char* DsoTypeToString(DsoType dso_type) {
	switch (dso_type) {
	case DSO_KERNEL:
	return "dso_kernel";
	case DSO_KERNEL_MODULE:
	return "dso_kernel_module";
	case DSO_ELF_FILE:
	return "dso_elf_file";
	default:
	return "unknown";
	}
	}