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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "thread_tree.h"
     18 
     19 #include <limits>
     20 
     21 #include <android-base/logging.h>
     22 
     23 #include "environment.h"
     24 #include "perf_event.h"
     25 #include "record.h"
     26 
     27 namespace simpleperf {
     28 
     29 bool MapComparator::operator()(const MapEntry* map1, const MapEntry* map2) const {
     30   if (map1->start_addr != map2->start_addr) {
     31     return map1->start_addr < map2->start_addr;
     32   }
     33   // Compare map->len instead of map->get_end_addr() here. Because we set map's len
     34   // to std::numeric_limits<uint64_t>::max() in FindMapByAddr(), which makes
     35   // map->get_end_addr() overflow.
     36   if (map1->len != map2->len) {
     37     return map1->len < map2->len;
     38   }
     39   if (map1->time != map2->time) {
     40     return map1->time < map2->time;
     41   }
     42   return false;
     43 }
     44 
     45 void ThreadTree::AddThread(int pid, int tid, const std::string& comm) {
     46   auto it = thread_tree_.find(tid);
     47   if (it == thread_tree_.end()) {
     48     ThreadEntry* thread = new ThreadEntry{
     49         pid, tid,
     50         "unknown",                             // comm
     51         std::set<MapEntry*, MapComparator>(),  // maps
     52     };
     53     auto pair = thread_tree_.insert(std::make_pair(tid, std::unique_ptr<ThreadEntry>(thread)));
     54     CHECK(pair.second);
     55     it = pair.first;
     56   }
     57   thread_comm_storage_.push_back(std::unique_ptr<std::string>(new std::string(comm)));
     58   it->second->comm = thread_comm_storage_.back()->c_str();
     59 }
     60 
     61 void ThreadTree::ForkThread(int pid, int tid, int ppid, int ptid) {
     62   ThreadEntry* parent = FindThreadOrNew(ppid, ptid);
     63   ThreadEntry* child = FindThreadOrNew(pid, tid);
     64   child->comm = parent->comm;
     65   child->maps = parent->maps;
     66 }
     67 
     68 ThreadEntry* ThreadTree::FindThreadOrNew(int pid, int tid) {
     69   auto it = thread_tree_.find(tid);
     70   if (it == thread_tree_.end()) {
     71     AddThread(pid, tid, "unknown");
     72     it = thread_tree_.find(tid);
     73   } else {
     74     if (pid != it->second.get()->pid) {
     75       // TODO: b/22185053.
     76       LOG(DEBUG) << "unexpected (pid, tid) pair: expected (" << it->second.get()->pid << ", " << tid
     77                  << "), actual (" << pid << ", " << tid << ")";
     78     }
     79   }
     80   return it->second.get();
     81 }
     82 
     83 void ThreadTree::AddKernelMap(uint64_t start_addr, uint64_t len, uint64_t pgoff, uint64_t time,
     84                               const std::string& filename) {
     85   // kernel map len can be 0 when record command is not run in supervisor mode.
     86   if (len == 0) {
     87     return;
     88   }
     89   Dso* dso = FindKernelDsoOrNew(filename);
     90   MapEntry* map = AllocateMap(MapEntry(start_addr, len, pgoff, time, dso));
     91   FixOverlappedMap(&kernel_map_tree_, map);
     92   auto pair = kernel_map_tree_.insert(map);
     93   CHECK(pair.second);
     94 }
     95 
     96 Dso* ThreadTree::FindKernelDsoOrNew(const std::string& filename) {
     97   if (filename == DEFAULT_KERNEL_MMAP_NAME) {
     98     if (kernel_dso_ == nullptr) {
     99       kernel_dso_ = Dso::CreateDso(DSO_KERNEL);
    100     }
    101     return kernel_dso_.get();
    102   }
    103   auto it = module_dso_tree_.find(filename);
    104   if (it == module_dso_tree_.end()) {
    105     module_dso_tree_[filename] = Dso::CreateDso(DSO_KERNEL_MODULE, filename);
    106     it = module_dso_tree_.find(filename);
    107   }
    108   return it->second.get();
    109 }
    110 
    111 void ThreadTree::AddThreadMap(int pid, int tid, uint64_t start_addr, uint64_t len, uint64_t pgoff,
    112                               uint64_t time, const std::string& filename) {
    113   ThreadEntry* thread = FindThreadOrNew(pid, tid);
    114   Dso* dso = FindUserDsoOrNew(filename);
    115   MapEntry* map = AllocateMap(MapEntry(start_addr, len, pgoff, time, dso));
    116   FixOverlappedMap(&thread->maps, map);
    117   auto pair = thread->maps.insert(map);
    118   CHECK(pair.second);
    119 }
    120 
    121 Dso* ThreadTree::FindUserDsoOrNew(const std::string& filename) {
    122   auto it = user_dso_tree_.find(filename);
    123   if (it == user_dso_tree_.end()) {
    124     user_dso_tree_[filename] = Dso::CreateDso(DSO_ELF_FILE, filename);
    125     it = user_dso_tree_.find(filename);
    126   }
    127   return it->second.get();
    128 }
    129 
    130 MapEntry* ThreadTree::AllocateMap(const MapEntry& value) {
    131   MapEntry* map = new MapEntry(value);
    132   map_storage_.push_back(std::unique_ptr<MapEntry>(map));
    133   return map;
    134 }
    135 
    136 void ThreadTree::FixOverlappedMap(std::set<MapEntry*, MapComparator>* map_set, const MapEntry* map) {
    137   for (auto it = map_set->begin(); it != map_set->end();) {
    138     if ((*it)->start_addr >= map->get_end_addr()) {
    139       // No more overlapped maps.
    140       break;
    141     }
    142     if ((*it)->get_end_addr() <= map->start_addr) {
    143       ++it;
    144     } else {
    145       MapEntry* old = *it;
    146       if (old->start_addr < map->start_addr) {
    147         MapEntry* before = AllocateMap(MapEntry(old->start_addr, map->start_addr - old->start_addr,
    148                                                 old->pgoff, old->time, old->dso));
    149         map_set->insert(before);
    150       }
    151       if (old->get_end_addr() > map->get_end_addr()) {
    152         MapEntry* after = AllocateMap(
    153             MapEntry(map->get_end_addr(), old->get_end_addr() - map->get_end_addr(),
    154                      map->get_end_addr() - old->start_addr + old->pgoff, old->time, old->dso));
    155         map_set->insert(after);
    156       }
    157 
    158       it = map_set->erase(it);
    159     }
    160   }
    161 }
    162 
    163 static bool IsAddrInMap(uint64_t addr, const MapEntry* map) {
    164   return (addr >= map->start_addr && addr < map->get_end_addr());
    165 }
    166 
    167 static MapEntry* FindMapByAddr(const std::set<MapEntry*, MapComparator>& maps, uint64_t addr) {
    168   // Construct a map_entry which is strictly after the searched map_entry, based on MapComparator.
    169   MapEntry find_map(addr, std::numeric_limits<uint64_t>::max(), 0,
    170                     std::numeric_limits<uint64_t>::max(), nullptr);
    171   auto it = maps.upper_bound(&find_map);
    172   if (it != maps.begin() && IsAddrInMap(addr, *--it)) {
    173     return *it;
    174   }
    175   return nullptr;
    176 }
    177 
    178 const MapEntry* ThreadTree::FindMap(const ThreadEntry* thread, uint64_t ip, bool in_kernel) {
    179   MapEntry* result = nullptr;
    180   if (!in_kernel) {
    181     result = FindMapByAddr(thread->maps, ip);
    182   } else {
    183     result = FindMapByAddr(kernel_map_tree_, ip);
    184   }
    185   return result != nullptr ? result : &unknown_map_;
    186 }
    187 
    188 const Symbol* ThreadTree::FindSymbol(const MapEntry* map, uint64_t ip) {
    189   uint64_t vaddr_in_file;
    190   if (map->dso == kernel_dso_.get()) {
    191     vaddr_in_file = ip;
    192   } else {
    193     vaddr_in_file = ip - map->start_addr + map->dso->MinVirtualAddress();
    194   }
    195   const Symbol* symbol = map->dso->FindSymbol(vaddr_in_file);
    196   if (symbol == nullptr) {
    197     symbol = &unknown_symbol_;
    198   }
    199   return symbol;
    200 }
    201 
    202 void ThreadTree::Clear() {
    203   thread_tree_.clear();
    204   thread_comm_storage_.clear();
    205   kernel_map_tree_.clear();
    206   map_storage_.clear();
    207   kernel_dso_.reset();
    208   module_dso_tree_.clear();
    209   user_dso_tree_.clear();
    210 }
    211 
    212 }  // namespace simpleperf
    213 
    214 void BuildThreadTree(const Record& record, ThreadTree* thread_tree) {
    215   if (record.header.type == PERF_RECORD_MMAP) {
    216     const MmapRecord& r = *static_cast<const MmapRecord*>(&record);
    217     if ((r.header.misc & PERF_RECORD_MISC_CPUMODE_MASK) == PERF_RECORD_MISC_KERNEL) {
    218       thread_tree->AddKernelMap(r.data.addr, r.data.len, r.data.pgoff, r.sample_id.time_data.time,
    219                                 r.filename);
    220     } else {
    221       thread_tree->AddThreadMap(r.data.pid, r.data.tid, r.data.addr, r.data.len, r.data.pgoff,
    222                                 r.sample_id.time_data.time, r.filename);
    223     }
    224   } else if (record.header.type == PERF_RECORD_MMAP2) {
    225     const Mmap2Record& r = *static_cast<const Mmap2Record*>(&record);
    226     if ((r.header.misc & PERF_RECORD_MISC_CPUMODE_MASK) == PERF_RECORD_MISC_KERNEL) {
    227       thread_tree->AddKernelMap(r.data.addr, r.data.len, r.data.pgoff, r.sample_id.time_data.time,
    228                                 r.filename);
    229     } else {
    230       std::string filename =
    231           (r.filename == DEFAULT_EXECNAME_FOR_THREAD_MMAP) ? "[unknown]" : r.filename;
    232       thread_tree->AddThreadMap(r.data.pid, r.data.tid, r.data.addr, r.data.len, r.data.pgoff,
    233                                 r.sample_id.time_data.time, filename);
    234     }
    235   } else if (record.header.type == PERF_RECORD_COMM) {
    236     const CommRecord& r = *static_cast<const CommRecord*>(&record);
    237     thread_tree->AddThread(r.data.pid, r.data.tid, r.comm);
    238   } else if (record.header.type == PERF_RECORD_FORK) {
    239     const ForkRecord& r = *static_cast<const ForkRecord*>(&record);
    240     thread_tree->ForkThread(r.data.pid, r.data.tid, r.data.ppid, r.data.ptid);
    241   }
    242 }
    243