[clang] [clang] Deflake the TimeProfile support tests (PR #138613)

[Reid Kleckner via cfe-commits]

https://github.com/rnk created https://github.com/llvm/llvm-project/pull/138613

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.

>From 935546b1d9f41b0dc1d6628bb641554186a0fb17 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk at google.com>
Date: Mon, 5 May 2025 23:18:24 +0000
Subject: [PATCH] [clang] Deflake the TimeProfile support tests

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.
---
 clang/unittests/Support/TimeProfilerTest.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

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