[XRay] convert FDR arg1 log entries

Summary:
A new FDR metadata record will support logging a function call argument;
appending multiple metadata records will represent a sequence of arguments
meaning that "holes" are not representable by the buffer format.  Each
call argument is currently a 64-bit value (useful for "this" pointers and
synchronization objects).

If present, we put this argument to the function call "entry" record it
belongs to, and alter its type to notify the user of its presence.

Reviewers: dberris

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32840

llvm-svn: 314269

1 files changed, 27 insertions, 2 deletions

diff --git a/llvm/lib/XRay/Trace.cpp b/llvm/lib/XRay/Trace.cpp
index 131c7807b1b..7f8846cbd6f 100644
--- a/llvm/lib/XRay/Trace.cpp
+++ b/llvm/lib/XRay/Trace.cpp
@@ -128,6 +128,7 @@ struct FDRState {
     FUNCTION_SEQUENCE,
     SCAN_TO_END_OF_THREAD_BUF,
     CUSTOM_EVENT_DATA,
+    CALL_ARGUMENT,
   };
   Token Expects;
 
@@ -151,6 +152,8 @@ const char *fdrStateToTwine(const FDRState::Token &state) {
     return "SCAN_TO_END_OF_THREAD_BUF";
   case FDRState::Token::CUSTOM_EVENT_DATA:
     return "CUSTOM_EVENT_DATA";
+  case FDRState::Token::CALL_ARGUMENT:
+    return "CALL_ARGUMENT";
   }
   return "UNKNOWN";
 }
@@ -238,6 +241,22 @@ Error processCustomEventMarker(FDRState &State, uint8_t RecordFirstByte,
   return Error::success();
 }
 
+/// State transition when a CallArgumentRecord is encountered.
+Error processFDRCallArgumentRecord(FDRState &State, uint8_t RecordFirstByte,
+                                   DataExtractor &RecordExtractor,
+                                   std::vector<XRayRecord> &Records) {
+  uint32_t OffsetPtr = 1; // Read starting after the first byte.
+  auto &Enter = Records.back();
+
+  if (Enter.Type != RecordTypes::ENTER)
+    return make_error<StringError>(
+        "CallArgument needs to be right after a function entry",
+        std::make_error_code(std::errc::executable_format_error));
+  Enter.Type = RecordTypes::ENTER_ARG;
+  Enter.CallArgs.emplace_back(RecordExtractor.getU64(&OffsetPtr));
+  return Error::success();
+}
+
 /// Advances the state machine for reading the FDR record type by reading one
 /// Metadata Record and updating the State appropriately based on the kind of
 /// record encountered. The RecordKind is encoded in the first byte of the
@@ -245,7 +264,8 @@ Error processCustomEventMarker(FDRState &State, uint8_t RecordFirstByte,
 /// to determine that this is a metadata record as opposed to a function record.
 Error processFDRMetadataRecord(FDRState &State, uint8_t RecordFirstByte,
                                DataExtractor &RecordExtractor,
-                               size_t &RecordSize) {
+                               size_t &RecordSize,
+                               std::vector<XRayRecord> &Records) {
   // The remaining 7 bits are the RecordKind enum.
   uint8_t RecordKind = RecordFirstByte >> 1;
   switch (RecordKind) {
@@ -279,6 +299,11 @@ Error processFDRMetadataRecord(FDRState &State, uint8_t RecordFirstByte,
                                           RecordExtractor, RecordSize))
       return E;
     break;
+  case 6: // CallArgument
+    if (auto E = processFDRCallArgumentRecord(State, RecordFirstByte,
+                                              RecordExtractor, Records))
+      return E;
+    break;
   default:
     // Widen the record type to uint16_t to prevent conversion to char.
     return make_error<StringError>(
@@ -434,7 +459,7 @@ Error loadFDRLog(StringRef Data, XRayFileHeader &FileHeader,
     if (isMetadataRecord) {
       RecordSize = 16;
       if (auto E = processFDRMetadataRecord(State, BitField, RecordExtractor,
-                                            RecordSize))
+                                            RecordSize, Records))
         return E;
     } else { // Process Function Record
       RecordSize = 8;