From 066c17585214eb705d2f48b56b864c2f5a2164b0 Mon Sep 17 00:00:00 2001
From: Ben Clayton <bclayton@google.com>
Date: Wed, 24 Nov 2021 00:08:28 +0000
Subject: [PATCH] writer/hlsl: Prevent NPE on error

If the HLSL sanitizer errors, then there may be no ArrayLengthFromUniform::Result, so we check the pointer before attempting to dereference it.

Bug: chromium:1273230
Change-Id: I9575d20748720623a94ac86f45da14302b20440a
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/70740
Auto-Submit: Ben Clayton <bclayton@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
---
 src/writer/hlsl/generator_impl.cc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/writer/hlsl/generator_impl.cc b/src/writer/hlsl/generator_impl.cc
index 1a24ed2138..5cc4ecc603 100644
--- a/src/writer/hlsl/generator_impl.cc
+++ b/src/writer/hlsl/generator_impl.cc
@@ -186,9 +186,10 @@ SanitizedResult Sanitize(
 
   SanitizedResult result;
   result.program = std::move(out.program);
-  result.used_array_length_from_uniform_indices =
-      std::move(out.data.Get<transform::ArrayLengthFromUniform::Result>()
-                    ->used_size_indices);
+  if (auto* res = out.data.Get<transform::ArrayLengthFromUniform::Result>()) {
+    result.used_array_length_from_uniform_indices =
+        std::move(res->used_size_indices);
+  }
   return result;
 }