[XRay][tools] Support tail-call exits before we write them in the runtime

Summary:
This change adds support for explicit tail-exit records to be written by
the XRay runtime. This lets us differentiate the tail exit
records/events in the log, and allows us to treat those exit events
especially in the future. For now we allow printing those out in YAML
(and reading them in).

Reviewers: kpw, pelikan

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D37964

llvm-svn: 313514

4 files changed, 12 insertions, 3 deletions

diff --git a/llvm/tools/llvm-xray/xray-account.cc b/llvm/tools/llvm-xray/xray-account.cc
index e97b4d8d1ed..74907044848 100644
--- a/llvm/tools/llvm-xray/xray-account.cc
+++ b/llvm/tools/llvm-xray/xray-account.cc
@@ -150,7 +150,8 @@ bool LatencyAccountant::accountRecord(const XRayRecord &Record) {
     ThreadStack.emplace_back(Record.FuncId, Record.TSC);
     break;
   }
-  case RecordTypes::EXIT: {
+  case RecordTypes::EXIT:
+  case RecordTypes::TAIL_EXIT: {
     if (ThreadStack.empty())
       return false;
 
@@ -419,6 +420,9 @@ template <> struct format_provider<llvm::xray::RecordTypes> {
       case RecordTypes::EXIT:
         Stream << "exit";
         break;
+      case RecordTypes::TAIL_EXIT:
+        Stream << "tail-exit";
+        break;
     }
   }
 };
diff --git a/llvm/tools/llvm-xray/xray-converter.cc b/llvm/tools/llvm-xray/xray-converter.cc
index 2583ec95149..4769186a19e 100644
--- a/llvm/tools/llvm-xray/xray-converter.cc
+++ b/llvm/tools/llvm-xray/xray-converter.cc
@@ -128,6 +128,9 @@ void TraceConverter::exportAsRAWv1(const Trace &Records, raw_ostream &OS) {
     case RecordTypes::EXIT:
       Writer.write(uint8_t{1});
       break;
+    case RecordTypes::TAIL_EXIT:
+      Writer.write(uint8_t{2});
+      break;
     }
     Writer.write(R.FuncId);
     Writer.write(R.TSC);
diff --git a/llvm/tools/llvm-xray/xray-graph.cc b/llvm/tools/llvm-xray/xray-graph.cc
index 685c24cb918..da2d04cf0b9 100644
--- a/llvm/tools/llvm-xray/xray-graph.cc
+++ b/llvm/tools/llvm-xray/xray-graph.cc
@@ -214,7 +214,8 @@ Error GraphRenderer::accountRecord(const XRayRecord &Record) {
     ThreadStack.push_back({Record.FuncId, Record.TSC});
     break;
   }
-  case RecordTypes::EXIT: {
+  case RecordTypes::EXIT:
+  case RecordTypes::TAIL_EXIT: {
     // FIXME: Refactor this and the account subcommand to reduce code
     // duplication
     if (ThreadStack.size() == 0 || ThreadStack.back().FuncId != Record.FuncId) {
diff --git a/llvm/tools/llvm-xray/xray-stacks.cc b/llvm/tools/llvm-xray/xray-stacks.cc
index 63982634576..40dcc31cd1f 100644
--- a/llvm/tools/llvm-xray/xray-stacks.cc
+++ b/llvm/tools/llvm-xray/xray-stacks.cc
@@ -352,7 +352,8 @@ public:
       }
       return AccountRecordStatus::OK;
     }
-    case RecordTypes::EXIT: {
+    case RecordTypes::EXIT:
+    case RecordTypes::TAIL_EXIT: {
       bool wasLastRecordExit = state->wasLastRecordExit;
       state->wasLastRecordExit = true;
       // The exit case is more interesting, since we want to be able to deduce