Add assertion about Mutex size.

Author: Patrick-6

src/concurrency/genmc/intercept.rs

@@ -1,6 +1,7 @@
 use rustc_middle::{throw_unsup_format, ty};
 use tracing::debug;
 
+use crate::concurrency::genmc::MAX_ACCESS_SIZE;
 use crate::concurrency::thread::EvalContextExt as _;
 use crate::*;
 
@@ -27,10 +28,15 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
         let this = self.eval_context_mut();
         let genmc_ctx = this.machine.data_race.as_genmc_ref().unwrap();
 
+        let size = mutex.layout.size.bytes();
+        assert!(
+            size < MAX_ACCESS_SIZE,
+            "Mutex is larger than maximal size of a memory access supported by GenMC ({size} >= {MAX_ACCESS_SIZE})"
+        );
         let result = genmc_ctx.handle.borrow_mut().pin_mut().handle_mutex_lock(
             genmc_ctx.active_thread_genmc_tid(&this.machine),
             mutex.ptr().addr().bytes(),
-            mutex.layout.size.bytes(),
+            size,
         );
         if let Some(error) = result.error.as_ref() {
             // FIXME(genmc): improve error handling.
@@ -87,10 +93,15 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
         debug!("GenMC: handling Mutex::try_lock()");
         let this = self.eval_context_mut();
         let genmc_ctx = this.machine.data_race.as_genmc_ref().unwrap();
+        let size = mutex.layout.size.bytes();
+        assert!(
+            size < MAX_ACCESS_SIZE,
+            "Mutex is larger than maximal size of a memory access supported by GenMC ({size} >= {MAX_ACCESS_SIZE})"
+        );
         let result = genmc_ctx.handle.borrow_mut().pin_mut().handle_mutex_try_lock(
             genmc_ctx.active_thread_genmc_tid(&this.machine),
             mutex.ptr().addr().bytes(),
-            mutex.layout.size.bytes(),
+            size,
         );
         if let Some(error) = result.error.as_ref() {
             // FIXME(genmc): improve error handling.