From 77f3081f84f60b4ce4081dfc517b3d1fe061fef6 Mon Sep 17 00:00:00 2001
From: Bastian Kersting <bkersting@google.com>
Date: Tue, 17 Dec 2024 13:00:22 +0000
Subject: [PATCH] Insert null checks for pointer dereferences when debug
 assertions are enabled

Similar to how the alignment is already checked, this adds a check
for null pointer dereferences in debug mode. It is implemented similarly
to the alignment check as a MirPass.

This is related to a 2025H1 project goal for better UB checks in debug
mode: https://github.com/rust-lang/rust-project-goals/pull/177.
---
 src/base.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/base.rs b/src/base.rs
index 34066eb83fc0..c7c9c6236d1d 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -417,6 +417,16 @@ fn codegen_fn_body(fx: &mut FunctionCx<'_, '_, '_>, start_block: Block) {
                             Some(source_info.span),
                         );
                     }
+                    AssertKind::NullPointerDereference => {
+                        let location = fx.get_caller_location(source_info).load_scalar(fx);
+
+                        codegen_panic_inner(
+                            fx,
+                            rustc_hir::LangItem::PanicNullPointerDereference,
+                            &[location],
+                            Some(source_info.span),
+                        )
+                    }
                     _ => {
                         let location = fx.get_caller_location(source_info).load_scalar(fx);