From c9af34ab285e40ae3285ccfd93d63a9470333b30 Mon Sep 17 00:00:00 2001
From: Victor Chiletto <vchiletto@codeweavers.com>
Date: Mon, 6 May 2024 07:53:14 -0300
Subject: [PATCH] vkd3d-shader/hlsl: Avoid a null pointer dereference in
 hlsl_block_cleanup (UBSan).

destroy_block() is called with a NULL block from:

* create_loop, through the loop rules for while and do-while loops.
* The selection_statement rule, in the case $6.else_block is NULL.
* free_parse_initializer.
---
 libs/vkd3d-shader/hlsl.y | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libs/vkd3d-shader/hlsl.y b/libs/vkd3d-shader/hlsl.y
index 79317bb0..c6b6219e 100644
--- a/libs/vkd3d-shader/hlsl.y
+++ b/libs/vkd3d-shader/hlsl.y
@@ -168,6 +168,9 @@ static struct list *make_empty_list(struct hlsl_ctx *ctx)
 
 static void destroy_block(struct hlsl_block *block)
 {
+    if (!block)
+        return;
+
     hlsl_block_cleanup(block);
     vkd3d_free(block);
 }