simpleperf: improve debug-unwind cmd.

In debug-unwind cmd:
1. Add --symfs option.
2. Add meta_info section when there isn't one.
3. Add file section when there isn't one.

Rename unwinding_result_reporter.py to debug_unwind_reporter.py,
and fix a small error in it.

Bug: http://b/72556486
Test: run simpleperf_unit_test.
Test: run debug_unwind_reporter.py manually.

Change-Id: Ibc66b7bfdc91a17f6f1c2c0e84f4769d2bcaa1e7

3 files changed, 77 insertions, 30 deletions

diff --git a/simpleperf/cmd_debug_unwind.cpp b/simpleperf/cmd_debug_unwind.cpp
index d356355c..cd96a759 100644
--- a/simpleperf/cmd_debug_unwind.cpp
+++ b/simpleperf/cmd_debug_unwind.cpp
@@ -88,6 +88,7 @@ class DebugUnwindCommand : public Command {
 "-i <file>  The path of record file generated with \"-g --no-unwind\".\n"
 "           Default is perf.data.\n"
 "-o <file>  The path ot write new perf.data. Default is perf.data.debug.\n"
+"--symfs <dir>  Look for files with symbols relative to this directory.\n"
 "--time time    Only unwind samples recorded at selected time.\n"
                 // clang-format on
                ),
@@ -159,6 +160,13 @@ bool DebugUnwindCommand::ParseOptions(const std::vector<std::string>& args) {
         return false;
       }
       output_filename_ = args[i];
+    } else if (args[i] == "--symfs") {
+      if (!NextArgumentOrError(args, &i)) {
+        return false;
+      }
+      if (!Dso::SetSymFsDir(args[i])) {
+        return false;
+      }
     } else if (args[i] == "--time") {
       if (!NextArgumentOrError(args, &i)) {
         return false;
@@ -339,34 +347,49 @@ bool DebugUnwindCommand::JoinCallChains() {
 }
 
 bool DebugUnwindCommand::WriteFeatureSections() {
+  // Add debug_unwind info in META_INFO section, and add symbol info in FILE section.
   const std::map<int, PerfFileFormat::SectionDesc>& features = reader_->FeatureSectionDescriptors();
-  if (!writer_->BeginWriteFeatures(features.size())) {
+  size_t new_feature_count = features.size();
+  for (int feature : {PerfFileFormat::FEAT_FILE, PerfFileFormat::FEAT_META_INFO}) {
+    if (features.find(feature) == features.end()) {
+      new_feature_count++;
+    }
+  }
+  if (!writer_->BeginWriteFeatures(new_feature_count)) {
     return false;
   }
-  for (auto& pair : features) {
-    int feature = pair.first;
-    if (feature == PerfFileFormat::FEAT_META_INFO) {
-      std::unordered_map<std::string, std::string> info_map;
-      if (!reader_->ReadMetaInfoFeature(&info_map)) {
-        return false;
-      }
-      info_map["debug_unwind"] = "true";
-      info_map["debug_unwind_mem_before"] = stat_.mem_before_unwinding.ToString();
-      info_map["debug_unwind_mem_after"] = stat_.mem_after_unwinding.ToString();
-      if (!writer_->WriteMetaInfoFeature(info_map)) {
-        return false;
-      }
-    } else if (feature == PerfFileFormat::FEAT_FILE) {
-      if (!writer_->WriteFileFeatures(thread_tree_.GetAllDsos())) {
-        return false;
-      }
-    } else {
-      std::vector<char> data;
-      if (!reader_->ReadFeatureSection(feature, &data) || !writer_->WriteFeature(feature, data)) {
-        return false;
-      }
+
+  auto it = features.begin();
+  // Copy all feature sections except FEAT_FILE and FEAT_META_INFO, which require special handling.
+  while (it != features.end() && it->first < PerfFileFormat::FEAT_FILE) {
+    std::vector<char> data;
+    if (!reader_->ReadFeatureSection(it->first, &data) || !writer_->WriteFeature(it->first, data)) {
+      return false;
     }
+    ++it;
+  }
+  // Write a new file section.
+  if (it != features.end() && it->first == PerfFileFormat::FEAT_FILE) {
+    ++it;
+  }
+  if (!writer_->WriteFileFeatures(thread_tree_.GetAllDsos())) {
+    return false;
+  }
+  // Write meta_info section.
+  std::unordered_map<std::string, std::string> info_map;
+  if (it != features.end() && it->first == PerfFileFormat::FEAT_META_INFO) {
+    if (!reader_->ReadMetaInfoFeature(&info_map)) {
+      return false;
+    }
+    ++it;
+  }
+  info_map["debug_unwind"] = "true";
+  info_map["debug_unwind_mem_before"] = stat_.mem_before_unwinding.ToString();
+  info_map["debug_unwind_mem_after"] = stat_.mem_after_unwinding.ToString();
+  if (!writer_->WriteMetaInfoFeature(info_map)) {
+    return false;
   }
+  CHECK(it == features.end());
   return writer_->EndWriteFeatures() && writer_->Close();
 }
 
@@ -388,7 +411,7 @@ void DebugUnwindCommand::PrintStat() {
   PrintIndented(1, "VmRSS: %s -> %s\n", stat_.mem_before_unwinding.vm_rss.c_str(),
                 stat_.mem_after_unwinding.vm_rss.c_str());
   callchain_joiner_.DumpStat();
-  printf("Please use unwinding_result_reporter.py to get a report in details.\n");
+  printf("Please use debug_unwind_reporter.py to get a report in details.\n");
 }
 
 void RegisterDebugUnwindCommand() {
diff --git a/simpleperf/cmd_debug_unwind_test.cpp b/simpleperf/cmd_debug_unwind_test.cpp
index bae45f6b..e6d44318 100644
--- a/simpleperf/cmd_debug_unwind_test.cpp
+++ b/simpleperf/cmd_debug_unwind_test.cpp
@@ -27,6 +27,7 @@
 
 #include "command.h"
 #include "get_test_data.h"
+#include "record_file.h"
 #include "test_util.h"
 
 #if defined(__aarch64__)
@@ -93,3 +94,26 @@ TEST(cmd_debug_unwind, smoke) {
   GTEST_LOG_(INFO) << "This test does nothing on non-ARM64 devices.";
 #endif
 }
+
+TEST(cmd_debug_unwind, symfs_option) {
+  // TODO: Remove the arch limitation once using cross-platform unwinding in the new unwinder.
+#if defined(__aarch64__)
+  std::string input_data = GetTestData(NATIVELIB_IN_APK_PERF_DATA);
+  CaptureStdout capture;
+  TemporaryFile tmp_file;
+  ASSERT_TRUE(capture.Start());
+  ASSERT_TRUE(DebugUnwindCmd()->Run({"-i", input_data, "-o", tmp_file.path, "--symfs",
+                                     GetTestDataDir()}));
+  ASSERT_NE(capture.Finish().find("Unwinding sample count: 55"), std::string::npos);
+  std::unique_ptr<RecordFileReader> reader = RecordFileReader::CreateInstance(tmp_file.path);
+  ASSERT_TRUE(reader);
+  const std::map<int, PerfFileFormat::SectionDesc>& features = reader->FeatureSectionDescriptors();
+  ASSERT_NE(features.find(PerfFileFormat::FEAT_FILE), features.end());
+  ASSERT_NE(features.find(PerfFileFormat::FEAT_META_INFO), features.end());
+  std::unordered_map<std::string, std::string> info_map;
+  ASSERT_TRUE(reader->ReadMetaInfoFeature(&info_map));
+  ASSERT_EQ(info_map["debug_unwind"], "true");
+#else
+  GTEST_LOG_(INFO) << "This test does nothing on non-ARM64 devices.";
+#endif
+}
diff --git a/simpleperf/scripts/unwinding_result_reporter.py b/simpleperf/scripts/debug_unwind_reporter.py
index 3eee00a6..56b51760 100644
--- a/simpleperf/scripts/unwinding_result_reporter.py
+++ b/simpleperf/scripts/debug_unwind_reporter.py
@@ -15,14 +15,14 @@
 # limitations under the License.
 #
 
-"""unwinding_result_reporter.py: report dwarf unwinding results generated by debug-unwind cmd.
-    Below is an example using unwinding_result_reporter.py:
+"""debug_unwind_reporter.py: report dwarf unwinding results generated by debug-unwind cmd.
+    Below is an example using debug_unwind_reporter.py:
     1. Record with "-g --no-unwind" option on device.
        simpleperf record -g --no-unwind --app com.google.sample.tunnel --duration 10
     2. Use debug-unwind cmd to unwind samples in perf.data on device.
        simpleperf debug-unwind
     3. Pull perf.data.debug on host, and report it with this script.
-       python unwinding_result_reporter.py
+       python debug_unwind_reporter.py
 
     It reports below items:
     1. time used for offline dwarf unwinding for each sample.
@@ -380,8 +380,8 @@ def build_unwinding_result_report(args):
                             stdout=subprocess.PIPE)
     (stdoutdata, _) = proc.communicate()
     if 'debug_unwind = true' not in stdoutdata:
-        log_exit("Can't parse unwinding result. Because %s is not generated by debug-unwind cmd."
-                 % record_file)
+        log_exit("Can't parse unwinding result. Because " +
+                 "%s was not generated by the debug-unwind cmd." % args.record_file[0])
     unwinding_report = UnwindingResultErrorReport(args.omit_callchains_fixed_by_joiner)
     process_maps = unwinding_report.process_maps
     lines = stdoutdata.split('\n')
@@ -454,7 +454,7 @@ def build_unwinding_result_report(args):
 
 def main():
     parser = argparse.ArgumentParser(
-        description='report dwarf unwinding results generated by debug-unwind cmd')
+        description='Report dwarf unwinding results generated by the debug-unwind cmd.')
     parser.add_argument('-i', '--record_file', nargs=1, default=['perf.data.debug'], help="""
                         Set profiling data to report. Default is perf.data.debug.""")
     parser.add_argument('--omit-callchains-fixed-by-joiner', action='store_true', help="""