simpleperf: export more info through report_lib_interface.

Make below changes to better suppport inferno:
1. Save product properties of device in perf.data.

2. Add a python/c api GetFeatureSection. It is used to support
reading record cmd and meta info from perf.data.

3. Remove old api GetNextMetaInfo, because meta info can be
exported by GetFeatureSection more easily.

4. When reading perf.data in record_file_reader.cpp, remove
callchain at and below ip == 0 to avoid caller's effort.

Also move to use android-base/properties.h.

Bug: http://b/64035530
Test: run simpleperf_unit_test and test.py.
Change-Id: Ib6743a09167e2b7cd65a12f17d991bc1ac628588

1 files changed, 21 insertions, 26 deletions

diff --git a/simpleperf/report_lib_interface.cpp b/simpleperf/report_lib_interface.cpp
index 79a2103c..88bb4d7e 100644
--- a/simpleperf/report_lib_interface.cpp
+++ b/simpleperf/report_lib_interface.cpp
@@ -72,9 +72,9 @@ struct CallChain {
   CallChainEntry* entries;
 };
 
-struct MetaInfoEntry {
-  const char* key;
-  const char* value;
+struct FeatureSection {
+  const char* data;
+  uint32_t data_size;
 };
 
 // Create a new instance,
@@ -96,7 +96,7 @@ SymbolEntry* GetSymbolOfCurrentSample(ReportLib* report_lib) EXPORT;
 CallChain* GetCallChainOfCurrentSample(ReportLib* report_lib) EXPORT;
 
 const char* GetBuildIdForPath(ReportLib* report_lib, const char* path) EXPORT;
-MetaInfoEntry* GetNextMetaInfo(ReportLib* report_lib) EXPORT;
+FeatureSection* GetFeatureSection(ReportLib* report_lib, const char* feature_name) EXPORT;
 }
 
 struct EventAttrWithName {
@@ -120,7 +120,6 @@ class ReportLib {
         current_thread_(nullptr),
         update_flag_(0),
         trace_offcpu_(false) {
-    current_meta_info_.key = current_meta_info_.value = nullptr;
   }
 
   bool SetLogSeverity(const char* log_level);
@@ -142,7 +141,7 @@ class ReportLib {
   CallChain* GetCallChainOfCurrentSample();
 
   const char* GetBuildIdForPath(const char* path);
-  MetaInfoEntry* GetNextMetaInfo();
+  FeatureSection* GetFeatureSection(const char* feature_name);
 
  private:
   Sample* GetCurrentSample();
@@ -164,12 +163,11 @@ class ReportLib {
   std::string build_id_string_;
   int update_flag_;
   std::vector<EventAttrWithName> event_attrs_;
-
-  std::unordered_map<std::string, std::string> meta_info_map_;
-  MetaInfoEntry current_meta_info_;
   std::unique_ptr<ScopedEventTypes> scoped_event_types_;
   bool trace_offcpu_;
   std::unordered_map<pid_t, std::unique_ptr<SampleRecord>> next_sample_cache_;
+  FeatureSection feature_section_;
+  std::vector<char> feature_section_data_;
 };
 
 bool ReportLib::SetLogSeverity(const char* log_level) {
@@ -200,16 +198,17 @@ bool ReportLib::OpenRecordFileIfNecessary() {
       return false;
     }
     record_file_reader_->LoadBuildIdAndFileFeatures(thread_tree_);
+    std::unordered_map<std::string, std::string> meta_info_map;
     if (record_file_reader_->HasFeature(PerfFileFormat::FEAT_META_INFO) &&
-        !record_file_reader_->ReadMetaInfoFeature(&meta_info_map_)) {
+        !record_file_reader_->ReadMetaInfoFeature(&meta_info_map)) {
       return false;
     }
-    auto it = meta_info_map_.find("event_type_info");
-    if (it != meta_info_map_.end()) {
+    auto it = meta_info_map.find("event_type_info");
+    if (it != meta_info_map.end()) {
       scoped_event_types_.reset(new ScopedEventTypes(it->second));
     }
-    it = meta_info_map_.find("trace_offcpu");
-    if (it != meta_info_map_.end()) {
+    it = meta_info_map.find("trace_offcpu");
+    if (it != meta_info_map.end()) {
       trace_offcpu_ = it->second == "true";
     }
   }
@@ -387,21 +386,17 @@ const char* ReportLib::GetBuildIdForPath(const char* path) {
   return build_id_string_.c_str();
 }
 
-MetaInfoEntry* ReportLib::GetNextMetaInfo() {
+FeatureSection* ReportLib::GetFeatureSection(const char* feature_name) {
   if (!OpenRecordFileIfNecessary()) {
     return nullptr;
   }
-  auto it = meta_info_map_.begin();
-  if (current_meta_info_.key != nullptr) {
-    it = meta_info_map_.find(current_meta_info_.key);
-    ++it;
-  }
-  if (it == meta_info_map_.end()) {
+  int feature = PerfFileFormat::GetFeatureId(feature_name);
+  if (feature == -1 || !record_file_reader_->ReadFeatureSection(feature, &feature_section_data_)) {
     return nullptr;
   }
-  current_meta_info_.key = it->first.c_str();
-  current_meta_info_.value = it->second.c_str();
-  return &current_meta_info_;
+  feature_section_.data = feature_section_data_.data();
+  feature_section_.data_size = feature_section_data_.size();
+  return &feature_section_;
 }
 
 // Exported methods working with a client created instance
@@ -453,6 +448,6 @@ const char* GetBuildIdForPath(ReportLib* report_lib, const char* path) {
   return report_lib->GetBuildIdForPath(path);
 }
 
-MetaInfoEntry* GetNextMetaInfo(ReportLib* report_lib) {
-  return report_lib->GetNextMetaInfo();
+FeatureSection* GetFeatureSection(ReportLib* report_lib, const char* feature_name) {
+  return report_lib->GetFeatureSection(feature_name);
 }