rustc_mir_transform/
check_inline.rs1use rustc_attr_parsing::InlineAttr;
5use rustc_hir::def_id::DefId;
6use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
7use rustc_middle::mir::{Body, TerminatorKind};
8use rustc_middle::ty;
9use rustc_middle::ty::TyCtxt;
10use rustc_span::sym;
11
12use crate::pass_manager::MirLint;
13
14pub(super) struct CheckForceInline;
15
16impl<'tcx> MirLint<'tcx> for CheckForceInline {
17 fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
18 let def_id = body.source.def_id();
19 if !tcx.hir().body_owner_kind(def_id).is_fn_or_closure() || !def_id.is_local() {
20 return;
21 }
22 let InlineAttr::Force { attr_span, .. } = tcx.codegen_fn_attrs(def_id).inline else {
23 return;
24 };
25
26 if let Err(reason) =
27 is_inline_valid_on_fn(tcx, def_id).and_then(|_| is_inline_valid_on_body(tcx, body))
28 {
29 tcx.dcx().emit_err(crate::errors::InvalidForceInline {
30 attr_span,
31 callee_span: tcx.def_span(def_id),
32 callee: tcx.def_path_str(def_id),
33 reason,
34 });
35 }
36 }
37}
38
39pub(super) fn is_inline_valid_on_fn<'tcx>(
40 tcx: TyCtxt<'tcx>,
41 def_id: DefId,
42) -> Result<(), &'static str> {
43 let codegen_attrs = tcx.codegen_fn_attrs(def_id);
44 if tcx.has_attr(def_id, sym::rustc_no_mir_inline) {
45 return Err("#[rustc_no_mir_inline]");
46 }
47
48 if tcx.sess.instrument_coverage_mcdc() {
51 return Err("incompatible with MC/DC coverage");
52 }
53
54 let ty = tcx.type_of(def_id);
55 if match ty.instantiate_identity().kind() {
56 ty::FnDef(..) => tcx.fn_sig(def_id).instantiate_identity().c_variadic(),
57 ty::Closure(_, args) => args.as_closure().sig().c_variadic(),
58 _ => false,
59 } {
60 return Err("C variadic");
61 }
62
63 if codegen_attrs.flags.contains(CodegenFnAttrFlags::COLD) {
64 return Err("cold");
65 }
66
67 if tcx.has_attr(def_id, sym::rustc_intrinsic) {
72 return Err("callee is an intrinsic");
73 }
74
75 Ok(())
76}
77
78pub(super) fn is_inline_valid_on_body<'tcx>(
79 _: TyCtxt<'tcx>,
80 body: &Body<'tcx>,
81) -> Result<(), &'static str> {
82 if body
83 .basic_blocks
84 .iter()
85 .any(|bb| matches!(bb.terminator().kind, TerminatorKind::TailCall { .. }))
86 {
87 return Err("can't inline functions with tail calls");
88 }
89
90 Ok(())
91}