Make TimingGuard a little safer

Author: bjorn3

src/driver/mod.rs

@@ -73,12 +73,14 @@ impl Drop for TimingGuard {
 
 impl cranelift_codegen::timing::ProfilerforMeasuremeProfiler{
 fnstart_pass(&self,pass: cranelift_codegen::timing::Pass) -> Box<dyn std::any::Any>{
-letmut timing_guard =
-TimingGuard{profiler: std::mem::ManuallyDrop::new(self.0.clone()),inner:None};
+letmut timing_guard = Box::new(TimingGuard{
+profiler: std::mem::ManuallyDrop::new(self.0.clone()),
+inner:None,
+});
  timing_guard.inner = Some(
 unsafe{&*(&*timing_guard.profileras&SelfProfilerRefas*constSelfProfilerRef)}
 .generic_activity(pass.description()),
 );
-Box::new(timing_guard)
+ timing_guard
 }
 }