From 3918b4783d4290b5d64e5c69c30ebaee87f2b125 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Thu, 15 Feb 2024 10:23:58 +0000
Subject: [PATCH] Workaround UB in cranelift-jit

---
 src/constant.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/constant.rs b/src/constant.rs
index b6de688130c7..18c5960ffc68 100644
--- a/src/constant.rs
+++ b/src/constant.rs
@@ -372,7 +372,13 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut dyn Module, cx: &mut Constant
         }
 
         let bytes = alloc.inspect_with_uninit_and_ptr_outside_interpreter(0..alloc.len()).to_vec();
-        data.define(bytes.into_boxed_slice());
+        if bytes.is_empty() {
+            // FIXME(bytecodealliance/wasmtime#7918) cranelift-jit has a bug where it causes UB on
+            // empty data objects
+            data.define(Box::new([0]));
+        } else {
+            data.define(bytes.into_boxed_slice());
+        }
 
         for &(offset, prov) in alloc.provenance().ptrs().iter() {
             let alloc_id = prov.alloc_id();