Rollup merge of #143293 - folkertdev:naked-function-kcfi, r=compiler-errors

fix `-Zsanitizer=kcfi` on `#[naked]` functions

fixes https://github.com/rust-lang/rust/issues/143266

With `-Zsanitizer=kcfi`, indirect calls happen via generated intermediate shim that forwards the call. The generated shim preserves the attributes of the original, including `#[unsafe(naked)]`. The shim is not a naked function though, and violates its invariants (like having a body that consists of a single `naked_asm!` call).

My fix here is to match on the `InstanceKind`, and only use `codegen_naked_asm` when the instance is not a `ReifyShim`. That does beg the question whether there are other `InstanceKind`s that could come up. As far as I can tell the answer is no: calling via `dyn` seems to work find, and `#[track_caller]` is disallowed in combination with `#[naked]`.

r? codegen
````@rustbot```` label +A-naked
cc ````@maurer```` ````@rcvalle````

3 files changed, 4 insertions, 4 deletions

diff --git a/compiler/rustc_codegen_cranelift/src/driver/aot.rs b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
index 442151fe32d..8ec3599b63d 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/aot.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
@@ -530,8 +530,8 @@ fn codegen_cgu_content(
     for (mono_item, item_data) in mono_items {
         match mono_item {
             MonoItem::Fn(instance) => {
-                if tcx.codegen_fn_attrs(instance.def_id()).flags.contains(CodegenFnAttrFlags::NAKED)
-                {
+                let flags = tcx.codegen_instance_attrs(instance.def).flags;
+                if flags.contains(CodegenFnAttrFlags::NAKED) {
                     rustc_codegen_ssa::mir::naked_asm::codegen_naked_asm(
                         &mut GlobalAsmContext { tcx, global_asm: &mut cx.global_asm },
                         instance,
diff --git a/compiler/rustc_codegen_cranelift/src/driver/jit.rs b/compiler/rustc_codegen_cranelift/src/driver/jit.rs
index b1f185b551c..b3497503bf0 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/jit.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/jit.rs
@@ -127,7 +127,7 @@ fn codegen_and_compile_fn<'tcx>(
     module: &mut dyn Module,
     instance: Instance<'tcx>,
 ) {
-    if tcx.codegen_fn_attrs(instance.def_id()).flags.contains(CodegenFnAttrFlags::NAKED) {
+    if tcx.codegen_instance_attrs(instance.def).flags.contains(CodegenFnAttrFlags::NAKED) {
         tcx.dcx()
             .span_fatal(tcx.def_span(instance.def_id()), "Naked asm is not supported in JIT mode");
     }
diff --git a/compiler/rustc_codegen_cranelift/src/driver/mod.rs b/compiler/rustc_codegen_cranelift/src/driver/mod.rs
index ffd47cace38..8f83c30b598 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/mod.rs
@@ -35,7 +35,7 @@ fn predefine_mono_items<'tcx>(
                         is_compiler_builtins,
                     );
                     let is_naked = tcx
-                        .codegen_fn_attrs(instance.def_id())
+                        .codegen_instance_attrs(instance.def)
                         .flags
                         .contains(CodegenFnAttrFlags::NAKED);
                     module