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add codegen_instance_attrs query
and use it for naked functions
1 parent 1e5c449 commit 42b8fa1

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7 files changed

+34
-23
lines changed

7 files changed

+34
-23
lines changed

compiler/rustc_codegen_cranelift/src/driver/aot.rs

Lines changed: 2 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -530,12 +530,8 @@ fn codegen_cgu_content(
530530
for (mono_item, item_data) in mono_items {
531531
match mono_item {
532532
MonoItem::Fn(instance) => {
533-
// Other `InstanceKind`s (e.g. `ReifyShim` generated by indirect calls) should be
534-
// codegened like a normal function.
535-
let is_item_instance = matches!(instance.def, InstanceKind::Item(_));
536-
537-
let flags = tcx.codegen_fn_attrs(instance.def_id()).flags;
538-
if is_item_instance && flags.contains(CodegenFnAttrFlags::NAKED) {
533+
let flags = tcx.codegen_instance_attrs(instance.def).flags;
534+
if flags.contains(CodegenFnAttrFlags::NAKED) {
539535
rustc_codegen_ssa::mir::naked_asm::codegen_naked_asm(
540536
&mut GlobalAsmContext { tcx, global_asm: &mut cx.global_asm },
541537
instance,

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -122,6 +122,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
122122
codegen_fn_attrs.export_name = Some(*name);
123123
}
124124
AttributeKind::Naked(_) => codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED,
125+
125126
AttributeKind::Align { align, .. } => codegen_fn_attrs.alignment = Some(*align),
126127
AttributeKind::LinkName { name, .. } => codegen_fn_attrs.link_name = Some(*name),
127128
AttributeKind::LinkSection { name, .. } => {

compiler/rustc_codegen_ssa/src/mir/debuginfo.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -356,7 +356,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
356356
LocalRef::Operand(operand) => {
357357
// Don't spill operands onto the stack in naked functions.
358358
// See: https://github.com/rust-lang/rust/issues/42779
359-
let attrs = bx.tcx().codegen_fn_attrs(self.instance.def_id());
359+
let attrs = bx.tcx().codegen_instance_attrs(self.instance.def);
360360
if attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
361361
return;
362362
}

compiler/rustc_codegen_ssa/src/mir/mod.rs

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -385,9 +385,8 @@ fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
385385

386386
let mut num_untupled = None;
387387

388-
let codegen_fn_attrs = bx.tcx().codegen_fn_attrs(fx.instance.def_id());
389-
let naked = codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED);
390-
if naked {
388+
let codegen_fn_attrs = bx.tcx().codegen_instance_attrs(fx.instance.def);
389+
if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
391390
return vec![];
392391
}
393392

compiler/rustc_codegen_ssa/src/mono_item.rs

Lines changed: 2 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,5 @@
11
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
22
use rustc_middle::mir::mono::{Linkage, MonoItem, MonoItemData, Visibility};
3-
use rustc_middle::ty::InstanceKind;
43
use rustc_middle::ty::layout::HasTyCtxt;
54
use tracing::debug;
65

@@ -42,12 +41,8 @@ impl<'a, 'tcx: 'a> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> {
4241
base::codegen_global_asm(cx, item_id);
4342
}
4443
MonoItem::Fn(instance) => {
45-
// Other `InstanceKind`s (e.g. `ReifyShim` generated by indirect calls) should be
46-
// codegened like a normal function.
47-
let is_item_instance = matches!(instance.def, InstanceKind::Item(_));
48-
49-
let flags = cx.tcx().codegen_fn_attrs(instance.def_id()).flags;
50-
if is_item_instance && flags.contains(CodegenFnAttrFlags::NAKED) {
44+
let flags = cx.tcx().codegen_instance_attrs(instance.def).flags;
45+
if flags.contains(CodegenFnAttrFlags::NAKED) {
5146
naked_asm::codegen_naked_asm::<Bx::CodegenCx>(cx, instance, item_data);
5247
} else {
5348
base::codegen_instance::<Bx>(cx, instance);

compiler/rustc_middle/src/middle/codegen_fn_attrs.rs

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,5 @@
1+
use std::borrow::Cow;
2+
13
use rustc_abi::Align;
24
use rustc_ast::expand::autodiff_attrs::AutoDiffAttrs;
35
use rustc_attr_data_structures::{InlineAttr, InstructionSetAttr, OptimizeAttr};
@@ -6,6 +8,24 @@ use rustc_span::Symbol;
68
use rustc_target::spec::SanitizerSet;
79

810
use crate::mir::mono::Linkage;
11+
use crate::ty::{InstanceKind, TyCtxt};
12+
13+
impl<'tcx> TyCtxt<'tcx> {
14+
pub fn codegen_instance_attrs(
15+
self,
16+
instance_kind: InstanceKind<'_>,
17+
) -> Cow<'tcx, CodegenFnAttrs> {
18+
let mut attrs = Cow::Borrowed(self.codegen_fn_attrs(instance_kind.def_id()));
19+
20+
// Drop the `#[naked]` attribute on non-item `InstanceKind`s, like the shims that
21+
// are generated for indirect function calls.
22+
if !matches!(instance_kind, InstanceKind::Item(_)) {
23+
attrs.to_mut().flags.remove(CodegenFnAttrFlags::NAKED);
24+
}
25+
26+
attrs
27+
}
28+
}
929

1030
#[derive(Clone, TyEncodable, TyDecodable, HashStable, Debug)]
1131
pub struct CodegenFnAttrs {

tests/codegen/sanitizer/kcfi/naked-function.rs

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -25,23 +25,23 @@ trait MyTrait {
2525
}
2626
impl MyTrait for Thing {}
2727

28+
// the shim calls the real function
29+
// CHECK-LABEL: define
30+
// CHECK-SAME: my_naked_function
31+
// CHECK-SAME: reify.shim.fnptr
32+
2833
// CHECK-LABEL: main
2934
#[unsafe(no_mangle)]
3035
pub fn main() {
3136
// Trick the compiler into generating an indirect call.
3237
const F: extern "C" fn() = Thing::my_naked_function;
3338

3439
// main calls the shim function
35-
// CHECK: call
40+
// CHECK: call void
3641
// CHECK-SAME: my_naked_function
3742
// CHECK-SAME: reify.shim.fnptr
3843
(F)();
3944
}
4045

41-
// the shim calls the real function
42-
// CHECK: define
43-
// CHECK-SAME: my_naked_function
44-
// CHECK-SAME: reify.shim.fnptr
45-
4646
// CHECK: declare !kcfi_type
4747
// CHECK-SAME: my_naked_function

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