From a9a80ef38615e1a69ec56dc8b00894fb525ecc7a Mon Sep 17 00:00:00 2001
From: Corentin Wallez <cwallez@chromium.org>
Date: Mon, 7 Feb 2022 16:12:00 +0000
Subject: [PATCH] Guard for [MTLDevice counterSets] being null.

Bug: dawn:1102
Change-Id: I1c8fffba65cba0b04ef72018013f027f0a814f90
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/79361
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Auto-Submit: Corentin Wallez <cwallez@chromium.org>
---
 src/dawn/native/metal/BackendMTL.mm | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/dawn/native/metal/BackendMTL.mm b/src/dawn/native/metal/BackendMTL.mm
index 52bcda76a0..21515a7b74 100644
--- a/src/dawn/native/metal/BackendMTL.mm
+++ b/src/dawn/native/metal/BackendMTL.mm
@@ -193,6 +193,12 @@ namespace dawn::native::metal {
             API_AVAILABLE(macos(10.15), ios(14.0)) {
             // MTLDevice’s counterSets property declares which counter sets it supports. Check
             // whether it's available on the device before requesting a counter set.
+
+            // On some systems, [device counterSets] is null and not an empty array.
+            if ([device counterSets] == nil) {
+                return false;
+            }
+
             id<MTLCounterSet> counterSet = nil;
             for (id<MTLCounterSet> set in [device counterSets]) {
                 if ([set.name caseInsensitiveCompare:counterSetName] == NSOrderedSame) {