Clean up FFI calls for operand bundles

compiler/rustc_codegen_llvm/src/llvm/mod.rs

@@ -2,11 +2,12 @@
 
 use std::cell::RefCell;
 use std::ffi::{CStr, CString};
+use std::ops::Deref;
+use std::ptr;
 use std::str::FromStr;
 use std::string::FromUtf8Error;
 
 use libc::c_uint;
-use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_llvm::RustString;
 use rustc_target::abi::{Align, Size, WrappingRange};
 
@@ -331,28 +332,43 @@ pub fn last_error() -> Option<String> {
     }
 }
 
-pub struct OperandBundleDef<'a> {
-    pub raw: &'a mut ffi::OperandBundleDef<'a>,
+/// Owns an [`OperandBundle`], and will dispose of it when dropped.
+pub(crate) struct OperandBundleOwned<'a> {
+    raw: ptr::NonNull<OperandBundle<'a>>,
 }
 
-impl<'a> OperandBundleDef<'a> {
-    pub fn new(name: &str, vals: &[&'a Value]) -> Self {
-        let name = SmallCStr::new(name);
-        let def = unsafe {
-            LLVMRustBuildOperandBundleDef(name.as_ptr(), vals.as_ptr(), vals.len() as c_uint)
+impl<'a> OperandBundleOwned<'a> {
+    pub(crate) fn new(name: &str, vals: &[&'a Value]) -> Self {
+        let raw = unsafe {
+            LLVMCreateOperandBundle(
+                name.as_c_char_ptr(),
+                name.len(),
+                vals.as_ptr(),
+                vals.len() as c_uint,
+            )
         };
-        OperandBundleDef { raw: def }
+        OperandBundleOwned { raw: ptr::NonNull::new(raw).unwrap() }
     }
 }
 
-impl Drop for OperandBundleDef<'_> {
+impl Drop for OperandBundleOwned<'_> {
     fn drop(&mut self) {
         unsafe {
-            LLVMRustFreeOperandBundleDef(&mut *(self.raw as *mut _));
+            LLVMDisposeOperandBundle(self.raw);
         }
     }
 }
 
+impl<'a> Deref for OperandBundleOwned<'a> {
+    type Target = OperandBundle<'a>;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: The returned reference is opaque and can only used for FFI.
+        // It is valid for as long as `&self` is.
+        unsafe { self.raw.as_ref() }
+    }
+}
+
 pub(crate) fn add_module_flag_u32(
     module: &Module,
     merge_behavior: ModuleFlagMergeBehavior,