From 65c65099c5e01f90583703060e2073077f65b079 Mon Sep 17 00:00:00 2001
From: Michael Crane <micran@microsoft.com>
Date: Tue, 14 Jul 2020 17:41:06 +0000
Subject: [PATCH] Cherry-pick PR #39599 into release-3.9

Component commits:
c8d5b9891d Load ETW module from a specified path
---
 src/compiler/perfLogger.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/compiler/perfLogger.ts b/src/compiler/perfLogger.ts
index 8ed8feac90c4c..f05e8a3bd1053 100644
--- a/src/compiler/perfLogger.ts
+++ b/src/compiler/perfLogger.ts
@@ -28,9 +28,11 @@ namespace ts {
     // See https://github.com/microsoft/typescript-etw for more information
     let etwModule;
     try {
-        // require() will throw an exception if the module is not installed
+        const etwModulePath = process.env.TS_ETW_MODULE_PATH ?? "./node_modules/@microsoft/typescript-etw";
+
+        // require() will throw an exception if the module is not found
         // It may also return undefined if not installed properly
-        etwModule = require("@microsoft/typescript-etw");
+        etwModule = require(etwModulePath);
     }
     catch (e) {
         etwModule = undefined;