Use a safe wrapper around an LLVM FFI function

Author: oli-obk

Diff for: compiler/rustc_codegen_llvm/src/asm.rs

@@ -533,7 +533,7 @@ pub(crate) fn inline_asm_call<'ll>(
                 ))
             }));
             let md = llvm::LLVMMDNodeInContext2(bx.llcx, srcloc.as_ptr(), srcloc.len());
-            let md = llvm::LLVMMetadataAsValue(&bx.llcx, md);
+            let md = bx.get_metadata_value(md);
             llvm::LLVMSetMetadata(call, kind, md);
 
             Some(call)

Diff for: compiler/rustc_codegen_llvm/src/consts.rs

@@ -490,7 +490,7 @@ impl<'ll> CodegenCx<'ll, '_> {
                         llvm::LLVMMDStringInContext2(self.llcx, bytes.as_c_char_ptr(), bytes.len());
                     let data = [section, alloc];
                     let meta = llvm::LLVMMDNodeInContext2(self.llcx, data.as_ptr(), data.len());
-                    let val = llvm::LLVMMetadataAsValue(self.llcx, meta);
+                    let val = self.get_metadata_value(meta);
                     llvm::LLVMAddNamedMetadataOperand(
                         self.llmod,
                         c"wasm.custom_sections".as_ptr(),

Diff for: compiler/rustc_codegen_llvm/src/context.rs

@@ -656,7 +656,7 @@ impl<'ll> SimpleCx<'ll> {
 
 impl<'ll, CX: Borrow<SCx<'ll>>> GenericCx<'ll, CX> {
     pub(crate) fn get_metadata_value(&self, metadata: &'ll Metadata) -> &'ll Value {
-        unsafe { llvm::LLVMMetadataAsValue(self.llcx(), metadata) }
+        llvm::LLVMMetadataAsValue(self.llcx(), metadata)
     }
 
     pub(crate) fn get_function(&self, name: &str) -> Option<&'ll Value> {
@@ -1225,9 +1225,14 @@ impl CodegenCx<'_, '_> {
 
 impl<'ll, CX: Borrow<SCx<'ll>>> GenericCx<'ll, CX> {
     /// A wrapper for [`llvm::LLVMSetMetadata`], but it takes `Metadata` as a parameter instead of `Value`.
-    pub(crate) fn set_metadata<'a>(&self, val: &'a Value, kind_id: MetadataType, md: &'a Metadata) {
+    pub(crate) fn set_metadata<'a>(
+        &self,
+        val: &'a Value,
+        kind_id: MetadataType,
+        md: &'ll Metadata,
+    ) {
+        let node = self.get_metadata_value(md);
         unsafe {
-            let node = llvm::LLVMMetadataAsValue(self.llcx(), md);
             llvm::LLVMSetMetadata(val, kind_id as c_uint, node);
         }
     }

Diff for: compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -649,7 +649,7 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
     fn type_test(&mut self, pointer: Self::Value, typeid: Self::Metadata) -> Self::Value {
         // Test the called operand using llvm.type.test intrinsic. The LowerTypeTests link-time
         // optimization pass replaces calls to this intrinsic with code to test type membership.
-        let typeid = unsafe { llvm::LLVMMetadataAsValue(&self.llcx, typeid) };
+        let typeid = self.get_metadata_value(typeid);
         self.call_intrinsic("llvm.type.test", &[pointer, typeid])
     }
 
@@ -659,7 +659,7 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
         vtable_byte_offset: u64,
         typeid: &'ll Metadata,
     ) -> Self::Value {
-        let typeid = unsafe { llvm::LLVMMetadataAsValue(&self.llcx, typeid) };
+        let typeid = self.get_metadata_value(typeid);
         let vtable_byte_offset = self.const_i32(vtable_byte_offset as i32);
         let type_checked_load =
             self.call_intrinsic("llvm.type.checked.load", &[llvtable, vtable_byte_offset, typeid]);

Diff for: compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -1680,7 +1680,7 @@ unsafe extern "C" {
         Packed: Bool,
     );
 
-    pub(crate) fn LLVMMetadataAsValue<'a>(C: &'a Context, MD: &'a Metadata) -> &'a Value;
+    pub(crate) safe fn LLVMMetadataAsValue<'a>(C: &'a Context, MD: &'a Metadata) -> &'a Value;
 
     pub(crate) fn LLVMSetUnnamedAddress(Global: &Value, UnnamedAddr: UnnamedAddr);