[clang] Deflake the TimeProfile support tests

[rnk]

These tests have been flaky since they were merged into the AllClangUnitTests binary, but the flakiness is inherent to the nature of timer-based tests.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Reid Kleckner (rnk)

Changes

These tests have been flaky since they were merged into the AllClangUnitTests binary, but the flakiness is inherent to the nature of timer-based tests.

---

Full diff: https://github.com/llvm/llvm-project/pull/138613.diff

1 Files Affected:

• (modified) clang/unittests/Support/TimeProfilerTest.cpp (+10)

diff --git a/clang/unittests/Support/TimeProfilerTest.cpp b/clang/unittests/Support/TimeProfilerTest.cpp
index f8053f2dfce48..7698742426dfc 100644
--- a/clang/unittests/Support/TimeProfilerTest.cpp
+++ b/clang/unittests/Support/TimeProfilerTest.cpp
@@ -155,6 +155,16 @@ std::string buildTraceGraph(StringRef Json) {
       bool InsideCurrentEvent =
           Event.TimestampBegin >= EventStack.top()->TimestampBegin &&
           Event.TimestampEnd <= EventStack.top()->TimestampEnd;
+
+      // Presumably due to timer rounding, PerformPendingInstantiations often
+      // appear to be within the timer interval of the immediately previous
+      // event group. We always know these events occur at level 1, not level 2,
+      // in our tests, so pop an event in that case.
+      if (InsideCurrentEvent && Event.Name == "PerformPendingInstantiations" &&
+          EventStack.size() == 2) {
+        InsideCurrentEvent = false;
+      }
+
       if (!InsideCurrentEvent)
         EventStack.pop();
       else

[AaronBallman]

LGTM!

[zmodem]

Was there a bug filed for this somewhere?

We're still seeing the flakiness on Mac, see https://crbug.com/394500612

I've disabled the test in http://github.com/llvm/llvm-project/commit/bf2653ed770f737a7950047f81724a104a7d0c79

@Izaron in case you want to look into it.