[XRay] Add CPU ID in Custom Event FDR Records

Summary:
This change cuts across compiler-rt and llvm, to increment the FDR log
version number to 4, and include the CPU ID in the custom event records.

This is a step towards allowing us to change the `llvm::xray::Trace`
object to start representing both custom and typed events in the stream
of records. Follow-on changes will allow us to change the kinds of
records we're presenting in the stream of traces, to incorporate the
data in custom/typed events.

A follow-on change will handle the typed event case, where it may not
fit within the 15-byte buffer for metadata records.

This work is part of the larger effort to enable writing analysis and
processing tools using a common in-memory representation of the events
found in traces. The work will focus on porting existing tools in LLVM
to use the common representation and informing the design of a
library/framework for expressing trace event analysis as C++ programs.

Reviewers: mboerger, eizan

Subscribers: hiraditya, mgrang, llvm-commits

Differential Revision: https://reviews.llvm.org/D53920

llvm-svn: 345798

include/llvm/XRay/FDRRecords.h

@@ -153,13 +153,14 @@ public:
 class CustomEventRecord : public MetadataRecord {
   int32_t Size = 0;
   uint64_t TSC = 0;
+  uint16_t CPU = 0;
   std::string Data{};
   friend class RecordInitializer;
 
 public:
   CustomEventRecord() = default;
-  explicit CustomEventRecord(uint64_t S, uint64_t T, std::string D)
-      : MetadataRecord(), Size(S), TSC(T), Data(std::move(D)) {}
+  explicit CustomEventRecord(uint64_t S, uint64_t T, uint16_t C, std::string D)
+      : MetadataRecord(), Size(S), TSC(T), CPU(C), Data(std::move(D)) {}
 
   MetadataType metadataType() const override {
     return MetadataType::CustomEvent;
@@ -167,6 +168,7 @@ public:
 
   int32_t size() const { return Size; }
   uint64_t tsc() const { return TSC; }
+  uint16_t cpu() const { return CPU; }
   StringRef data() const { return Data; }
 
   Error apply(RecordVisitor &V) override;
@@ -272,10 +274,16 @@ public:
 class RecordInitializer : public RecordVisitor {
   DataExtractor &E;
   uint32_t &OffsetPtr;
+  uint16_t Version;
 
 public:
+  static constexpr uint16_t DefaultVersion = 4u;
+
+  explicit RecordInitializer(DataExtractor &DE, uint32_t &OP, uint16_t V)
+      : RecordVisitor(), E(DE), OffsetPtr(OP), Version(V) {}
+
   explicit RecordInitializer(DataExtractor &DE, uint32_t &OP)
-      : RecordVisitor(), E(DE), OffsetPtr(OP) {}
+      : RecordInitializer(DE, OP, DefaultVersion) {}
 
   Error visit(BufferExtents &) override;
   Error visit(WallclockRecord &) override;

lib/XRay/FDRTraceWriter.cpp

@@ -94,9 +94,10 @@ Error FDRTraceWriter::visit(TSCWrapRecord &R) {
 }
 
 Error FDRTraceWriter::visit(CustomEventRecord &R) {
-  if (auto E = writeMetadata<5u>(OS, R.size(), R.tsc()))
+  if (auto E = writeMetadata<5u>(OS, R.size(), R.tsc(), R.cpu()))
     return E;
-  ArrayRef<char> Bytes(R.data().data(), R.data().size());
+  auto D = R.data();
+  ArrayRef<char> Bytes(D.data(), D.size());
   OS.write(Bytes);
   return Error::success();
 }
@@ -127,7 +128,7 @@ Error FDRTraceWriter::visit(FunctionRecord &R) {
   OS.write(TypeRecordFuncId);
   OS.write(R.delta());
   return Error::success();
-} // namespace xray
+}
 
 } // namespace xray
 } // namespace llvm

lib/XRay/FileHeaderReader.cpp

@@ -63,8 +63,7 @@ Expected<XRayFileHeader> readBinaryFormatHeader(DataExtractor &HeaderExtractor,
   // Manually advance the offset pointer 16 bytes, after getting a raw memcpy
   // from the underlying data.
   OffsetPtr += 16;
-  if (FileHeader.Version != 1 && FileHeader.Version != 2 &&
-      FileHeader.Version != 3)
+  if (FileHeader.Version < 1 || FileHeader.Version > 4)
     return createStringError(std::make_error_code(std::errc::invalid_argument),
                              "Unsupported XRay file version: %d at offset %d",
                              FileHeader.Version, OffsetPtr);

lib/XRay/RecordInitializer.cpp

@@ -118,6 +118,19 @@ Error RecordInitializer::visit(CustomEventRecord &R) {
         std::make_error_code(std::errc::invalid_argument),
         "Cannot read a custom event TSC field at offset %d.", OffsetPtr);
 
+  // For version 4 onwards, of the FDR log, we want to also capture the CPU ID
+  // of the custom event.
+  if (Version >= 4) {
+    PreReadOffset = OffsetPtr;
+    R.CPU = E.getU16(&OffsetPtr);
+    if (PreReadOffset == OffsetPtr)
+      return createStringError(
+          std::make_error_code(std::errc::invalid_argument),
+          "Missing CPU field at offset %d", OffsetPtr);
+  }
+
+  assert(OffsetPtr > BeginOffset &&
+         OffsetPtr - BeginOffset <= MetadataRecord::kMetadataBodySize);
   OffsetPtr += MetadataRecord::kMetadataBodySize - (OffsetPtr - BeginOffset);
 
   // Next we read in a fixed chunk of data from the given offset.

lib/XRay/RecordPrinter.cpp

@@ -35,8 +35,9 @@ Error RecordPrinter::visit(TSCWrapRecord &R) {
 }
 
 Error RecordPrinter::visit(CustomEventRecord &R) {
-  OS << formatv("<Custom Event: tsc = {0}, size = {1}, data = '{2}'>", R.tsc(),
-                R.size(), R.data())
+  OS << formatv(
+            "<Custom Event: tsc = {0}, cpu = {1}, size = {2}, data = '{3}'>",
+            R.tsc(), R.cpu(), R.size(), R.data())
      << Delim;
   return Error::success();
 }

lib/XRay/Trace.cpp

@@ -310,12 +310,11 @@ Error loadFDRLog(StringRef Data, bool IsLittleEndian,
   {
     for (auto &PTB : Index) {
       auto &Blocks = PTB.second;
-      llvm::sort(
-          Blocks,
-          [](const BlockIndexer::Block &L, const BlockIndexer::Block &R) {
-            return (L.WallclockTime->seconds() < R.WallclockTime->seconds() &&
-                    L.WallclockTime->nanos() < R.WallclockTime->nanos());
-          });
+      llvm::sort(Blocks, [](const BlockIndexer::Block &L,
+                            const BlockIndexer::Block &R) {
+        return (L.WallclockTime->seconds() < R.WallclockTime->seconds() &&
+                L.WallclockTime->nanos() < R.WallclockTime->nanos());
+      });
       auto Adder = [&](const XRayRecord &R) { Records.push_back(R); };
       TraceExpander Expander(Adder, FileHeader.Version);
       for (auto &B : Blocks) {
@@ -435,7 +434,7 @@ Expected<Trace> llvm::xray::loadTrace(const DataExtractor &DE, bool Sort) {
     }
     break;
   case FLIGHT_DATA_RECORDER_FORMAT:
-    if (Version == 1 || Version == 2 || Version == 3) {
+    if (Version >= 1 && Version <= 4) {
       if (auto E = loadFDRLog(DE.getData(), DE.isLittleEndian(), T.FileHeader,
                               T.Records))
         return std::move(E);

unittests/XRay/FDRProducerConsumerTest.cpp

@@ -54,7 +54,7 @@ template <> std::unique_ptr<Record> MakeRecord<WallclockRecord>() {
 }
 
 template <> std::unique_ptr<Record> MakeRecord<CustomEventRecord>() {
-  return make_unique<CustomEventRecord>(4, 1, "data");
+  return make_unique<CustomEventRecord>(4, 1, 2, "data");
 }
 
 template <> std::unique_ptr<Record> MakeRecord<CallArgRecord>() {

unittests/XRay/FDRRecordPrinterTest.cpp

@@ -55,11 +55,11 @@ template <> struct Helper<TSCWrapRecord> {
 
 template <> struct Helper<CustomEventRecord> {
   static std::unique_ptr<Record> construct() {
-    return make_unique<CustomEventRecord>(4, 1, "data");
+    return make_unique<CustomEventRecord>(4, 1, 2, "data");
   }
 
   static const char *expected() {
-    return "<Custom Event: tsc = 1, size = 4, data = 'data'>";
+    return "<Custom Event: tsc = 1, cpu = 2, size = 4, data = 'data'>";
   }
 };