From e1c4d88b46409bb1b3835d7a8960e5ae6a51cd8b Mon Sep 17 00:00:00 2001
From: Mike Hommey <mh+mozilla@glandium.org>
Date: Tue, 20 Apr 2021 05:48:08 +0000
Subject: [PATCH] Bug 1705727 - Disable tail call tests in TestStackWalk for
 code-coverage builds. r=gerald

Differential Revision: https://phabricator.services.mozilla.com/D112689
---
 mozglue/tests/gtest/TestStackWalk.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mozglue/tests/gtest/TestStackWalk.cpp b/mozglue/tests/gtest/TestStackWalk.cpp
index 8c842c3a3a0d..064d5abfa4c4 100644
--- a/mozglue/tests/gtest/TestStackWalk.cpp
+++ b/mozglue/tests/gtest/TestStackWalk.cpp
@@ -24,11 +24,13 @@ struct CallInfo {
   bool mTailCall;
 
   bool TailCall() {
-#ifdef __i386__
+#if defined(__i386__) || defined(MOZ_CODE_COVERAGE)
     // We can't make tail calls happen on i386 because all arguments to
     // functions are on the stack, so the stack pointer needs to be updated
     // before the call and restored after the call, so tail call optimization
     // never happens.
+    // Similarly, code-coverage flags don't guarantee that tail call
+    // optimization will happen.
     return false;
 #else
     return mTailCall;