Rollup merge of #89376 - andjo403:selfProfileUseAfterDropFix, r=Mark-Simulacrum

Fix use after drop in self-profile with llvm events

self-profile with `-Z self-profile-events=llvm` have failed with a segmentation fault due to this use after drop.
this type of events can be more useful now that the new passmanager is the default.

Author: fee1-dead

Diff for: compiler/rustc_codegen_llvm/src/back/write.rs

@@ -406,13 +406,15 @@ pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
         None
     };
 
-    let llvm_selfprofiler = if cgcx.prof.llvm_recording_enabled() {
-        let mut llvm_profiler = LlvmSelfProfiler::new(cgcx.prof.get_self_profiler().unwrap());
-        &mut llvm_profiler as *mut _ as *mut c_void
+    let mut llvm_profiler = if cgcx.prof.llvm_recording_enabled() {
+        Some(LlvmSelfProfiler::new(cgcx.prof.get_self_profiler().unwrap()))
     } else {
-        std::ptr::null_mut()
+        None
     };
 
+    let llvm_selfprofiler =
+        llvm_profiler.as_mut().map(|s| s as *mut _ as *mut c_void).unwrap_or(std::ptr::null_mut());
+
     let extra_passes = config.passes.join(",");
 
     // FIXME: NewPM doesn't provide a facility to pass custom InlineParams.