Merge "[ART] Prepare streaming output of method tracing for developer use."
diff --git a/runtime/trace.cc b/runtime/trace.cc
index 9d9360e..2add955 100644
--- a/runtime/trace.cc
+++ b/runtime/trace.cc
@@ -54,6 +54,7 @@
     static_cast<size_t>(kTraceMethodActionMask));
 static constexpr uint8_t kOpNewMethod = 1U;
 static constexpr uint8_t kOpNewThread = 2U;
+static constexpr uint8_t kOpTraceSummary = 3U;
 
 class BuildStackTraceVisitor : public StackVisitor {
  public:
@@ -700,20 +701,19 @@
   std::string header(os.str());
 
   if (trace_output_mode_ == TraceOutputMode::kStreaming) {
-    File file(streaming_file_name_ + ".sec", O_CREAT | O_WRONLY, true);
-    if (!file.IsOpened()) {
-      LOG(WARNING) << "Could not open secondary trace file!";
-      return;
-    }
-    if (!file.WriteFully(header.c_str(), header.length())) {
-      file.Erase();
-      std::string detail(StringPrintf("Trace data write failed: %s", strerror(errno)));
-      PLOG(ERROR) << detail;
-      ThrowRuntimeException("%s", detail.c_str());
-    }
-    if (file.FlushCloseOrErase() != 0) {
-      PLOG(ERROR) << "Could not write secondary file";
-    }
+    MutexLock mu(Thread::Current(), *streaming_lock_);  // To serialize writing.
+    // Write a special token to mark the end of trace records and the start of
+    // trace summary.
+    uint8_t buf[7];
+    Append2LE(buf, 0);
+    buf[2] = kOpTraceSummary;
+    Append4LE(buf + 3, static_cast<uint32_t>(header.length()));
+    WriteToBuf(buf, sizeof(buf));
+    // Write the trace summary. The summary is identical to the file header when
+    // the output mode is not streaming (except for methods).
+    WriteToBuf(reinterpret_cast<const uint8_t*>(header.c_str()), header.length());
+    // Flush the buffer, which may include some trace records before the summary.
+    FlushBuf();
   } else {
     if (trace_file_.get() == nullptr) {
       iovec iov[2];
@@ -894,6 +894,14 @@
   memcpy(buf_.get() + old_offset, src, src_size);
 }
 
+void Trace::FlushBuf() {
+  int32_t offset = cur_offset_.LoadRelaxed();
+  if (!trace_file_->WriteFully(buf_.get(), offset)) {
+    PLOG(WARNING) << "Failed flush the remaining data in streaming.";
+  }
+  cur_offset_.StoreRelease(0);
+}
+
 void Trace::LogMethodTraceEvent(Thread* thread, ArtMethod* method,
                                 instrumentation::Instrumentation::InstrumentationEvent event,
                                 uint32_t thread_clock_diff, uint32_t wall_clock_diff) {
diff --git a/runtime/trace.h b/runtime/trace.h
index 824b150..485e9a1 100644
--- a/runtime/trace.h
+++ b/runtime/trace.h
@@ -202,7 +202,8 @@
       // This causes the negative annotations to incorrectly have a false positive. TODO: Figure out
       // how to annotate this.
       NO_THREAD_SAFETY_ANALYSIS;
-  void FinishTracing() REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!*unique_methods_lock_);
+  void FinishTracing()
+      REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!*unique_methods_lock_, !*streaming_lock_);
 
   void ReadClocks(Thread* thread, uint32_t* thread_clock_diff, uint32_t* wall_clock_diff);
 
@@ -229,6 +230,9 @@
   // annotation.
   void WriteToBuf(const uint8_t* src, size_t src_size)
       REQUIRES(streaming_lock_);
+  // Flush the main buffer to file. Used for streaming. Exposed here for lock annotation.
+  void FlushBuf()
+      REQUIRES(streaming_lock_);
 
   uint32_t EncodeTraceMethod(ArtMethod* method) REQUIRES(!*unique_methods_lock_);
   uint32_t EncodeTraceMethodAndAction(ArtMethod* method, TraceAction action)
diff --git a/tools/stream-trace-converter.py b/tools/stream-trace-converter.py
index 951b05b..7e341f2 100755
--- a/tools/stream-trace-converter.py
+++ b/tools/stream-trace-converter.py
@@ -124,12 +124,20 @@
     self._threads.append('%d\t%s\n' % (tid, str))
     print 'New thread: %d/%s' % (tid, str)
 
+  def ProcessTraceSummary(self, input):
+    summaryLength = ReadIntLE(input)
+    str = input.read(summaryLength)
+    self._summary = str
+    print 'Summary: \"%s\"' % str
+
   def ProcessSpecial(self, input):
     code = ord(input.read(1))
     if code == 1:
       self.ProcessMethod(input)
     elif code == 2:
       self.ProcessThread(input)
+    elif code == 3:
+      self.ProcessTraceSummary(input)
     else:
       raise MyException("Unknown special!")
 
@@ -147,9 +155,24 @@
       print 'Buffer underrun, file was probably truncated. Results should still be usable.'
 
   def Finalize(self, header):
-    header.write('*threads\n')
-    for t in self._threads:
-      header.write(t)
+    # If the summary is present in the input file, use it as the header except
+    # for the methods section which is emtpy in the input file. If not present,
+    # apppend header with the threads that are recorded in the input stream.
+    if (self._summary):
+      # Erase the contents that's already written earlier by PrintHeader.
+      header.seek(0)
+      header.truncate()
+      # Copy the lines from the input summary to the output header until
+      # the methods section is seen.
+      for line in self._summary.splitlines(True):
+        if line == "*methods\n":
+          break
+        else:
+          header.write(line)
+    else:
+      header.write('*threads\n')
+      for t in self._threads:
+        header.write(t)
     header.write('*methods\n')
     for m in self._methods:
       header.write(m)
@@ -166,6 +189,7 @@
 
     self._methods = []
     self._threads = []
+    self._summary = None
     self.Process(input, body)
 
     self.Finalize(header)