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Auto merge of #98489 - cjgillot:naked-nohir, r=davidtwco,tmiasko
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Only fetch HIR for naked functions that have the attribute.
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@bors
bors committed Aug 8, 2022
2 parents 6a11cad + 6eb0c89 commit 9b8cfc1
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Showing 2 changed files with 86 additions and 111 deletions.
94 changes: 41 additions & 53 deletions compiler/rustc_passes/src/naked_functions.rs
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Original file line number Diff line number Diff line change
@@ -1,83 +1,71 @@
//! Checks validity of naked functions.

use rustc_ast::{Attribute, InlineAsmOptions};
use rustc_ast::InlineAsmOptions;
use rustc_errors::{struct_span_err, Applicability};
use rustc_hir as hir;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::LocalDefId;
use rustc_hir::intravisit::{FnKind, Visitor};
use rustc_hir::{ExprKind, HirId, InlineAsmOperand, StmtKind};
use rustc_hir::intravisit::Visitor;
use rustc_hir::{ExprKind, InlineAsmOperand, StmtKind};
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::TyCtxt;
use rustc_session::lint::builtin::UNDEFINED_NAKED_FUNCTION_ABI;
use rustc_span::symbol::sym;
use rustc_span::Span;
use rustc_target::spec::abi::Abi;

fn check_mod_naked_functions(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
tcx.hir().visit_item_likes_in_module(module_def_id, &mut CheckNakedFunctions { tcx });
}

pub(crate) fn provide(providers: &mut Providers) {
*providers = Providers { check_mod_naked_functions, ..*providers };
}

struct CheckNakedFunctions<'tcx> {
tcx: TyCtxt<'tcx>,
}

impl<'tcx> Visitor<'tcx> for CheckNakedFunctions<'tcx> {
fn visit_fn(
&mut self,
fk: FnKind<'_>,
_fd: &'tcx hir::FnDecl<'tcx>,
body_id: hir::BodyId,
span: Span,
hir_id: HirId,
) {
let ident_span;
let fn_header;

match fk {
FnKind::Closure => {
// Closures with a naked attribute are rejected during attribute
// check. Don't validate them any further.
return;
}
FnKind::ItemFn(ident, _, ref header, ..) => {
ident_span = ident.span;
fn_header = header;
}

FnKind::Method(ident, ref sig, ..) => {
ident_span = ident.span;
fn_header = &sig.header;
}
fn check_mod_naked_functions(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
let items = tcx.hir_module_items(module_def_id);
for def_id in items.definitions() {
if !matches!(tcx.def_kind(def_id), DefKind::Fn | DefKind::AssocFn) {
continue;
}

let attrs = self.tcx.hir().attrs(hir_id);
let naked = attrs.iter().any(|attr| attr.has_name(sym::naked));
if naked {
let body = self.tcx.hir().body(body_id);
check_abi(self.tcx, hir_id, fn_header.abi, ident_span);
check_no_patterns(self.tcx, body.params);
check_no_parameters_use(self.tcx, body);
check_asm(self.tcx, body, span);
check_inline(self.tcx, attrs);
let naked = tcx.has_attr(def_id.to_def_id(), sym::naked);
if !naked {
continue;
}

let (fn_header, body_id) = match tcx.hir().get_by_def_id(def_id) {
hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, _, body_id), .. })
| hir::Node::TraitItem(hir::TraitItem {
kind: hir::TraitItemKind::Fn(sig, hir::TraitFn::Provided(body_id)),
..
})
| hir::Node::ImplItem(hir::ImplItem {
kind: hir::ImplItemKind::Fn(sig, body_id),
..
}) => (sig.header, *body_id),
_ => continue,
};

let body = tcx.hir().body(body_id);
check_abi(tcx, def_id, fn_header.abi);
check_no_patterns(tcx, body.params);
check_no_parameters_use(tcx, body);
check_asm(tcx, def_id, body);
check_inline(tcx, def_id);
}
}

/// Check that the function isn't inlined.
fn check_inline(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
for attr in attrs.iter().filter(|attr| attr.has_name(sym::inline)) {
fn check_inline(tcx: TyCtxt<'_>, def_id: LocalDefId) {
let attrs = tcx.get_attrs(def_id.to_def_id(), sym::inline);
for attr in attrs {
tcx.sess.struct_span_err(attr.span, "naked functions cannot be inlined").emit();
}
}

/// Checks that function uses non-Rust ABI.
fn check_abi(tcx: TyCtxt<'_>, hir_id: HirId, abi: Abi, fn_ident_span: Span) {
fn check_abi(tcx: TyCtxt<'_>, def_id: LocalDefId, abi: Abi) {
if abi == Abi::Rust {
tcx.struct_span_lint_hir(UNDEFINED_NAKED_FUNCTION_ABI, hir_id, fn_ident_span, |lint| {
let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
let span = tcx.def_span(def_id);
tcx.struct_span_lint_hir(UNDEFINED_NAKED_FUNCTION_ABI, hir_id, span, |lint| {
lint.build("Rust ABI is unsupported in naked functions").emit();
});
}
Expand Down Expand Up @@ -141,15 +129,15 @@ impl<'tcx> Visitor<'tcx> for CheckParameters<'tcx> {
}

/// Checks that function body contains a single inline assembly block.
fn check_asm<'tcx>(tcx: TyCtxt<'tcx>, body: &'tcx hir::Body<'tcx>, fn_span: Span) {
fn check_asm<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId, body: &'tcx hir::Body<'tcx>) {
let mut this = CheckInlineAssembly { tcx, items: Vec::new() };
this.visit_body(body);
if let [(ItemKind::Asm | ItemKind::Err, _)] = this.items[..] {
// Ok.
} else {
let mut diag = struct_span_err!(
tcx.sess,
fn_span,
tcx.def_span(def_id),
E0787,
"naked functions must contain a single asm block"
);
Expand Down
103 changes: 45 additions & 58 deletions src/test/ui/asm/naked-functions.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -57,13 +57,11 @@ LL | a + 1
error[E0787]: naked functions must contain a single asm block
--> $DIR/naked-functions.rs:33:1
|
LL | / pub unsafe extern "C" fn inc(a: u32) -> u32 {
LL | |
LL | | a + 1
| | ----- non-asm is unsupported in naked functions
LL | |
LL | | }
| |_^
LL | pub unsafe extern "C" fn inc(a: u32) -> u32 {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL |
LL | a + 1
| ----- non-asm is unsupported in naked functions

error: referencing function parameters is not allowed in naked functions
--> $DIR/naked-functions.rs:42:31
Expand All @@ -82,12 +80,11 @@ LL | asm!("/* {0} */", in(reg) a, options(noreturn));
error[E0787]: naked functions must contain a single asm block
--> $DIR/naked-functions.rs:48:1
|
LL | / pub unsafe extern "C" fn inc_closure(a: u32) -> u32 {
LL | |
LL | | (|| a + 1)()
| | ------------ non-asm is unsupported in naked functions
LL | | }
| |_^
LL | pub unsafe extern "C" fn inc_closure(a: u32) -> u32 {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL |
LL | (|| a + 1)()
| ------------ non-asm is unsupported in naked functions

error[E0787]: only `const` and `sym` operands are supported in naked functions
--> $DIR/naked-functions.rs:65:10
Expand Down Expand Up @@ -124,30 +121,25 @@ LL | sym G, options(noreturn),
error[E0787]: naked functions must contain a single asm block
--> $DIR/naked-functions.rs:54:1
|
LL | / pub unsafe extern "C" fn unsupported_operands() {
LL | |
LL | | let mut a = 0usize;
| | ------------------- non-asm is unsupported in naked functions
LL | | let mut b = 0usize;
| | ------------------- non-asm is unsupported in naked functions
LL | | let mut c = 0usize;
| | ------------------- non-asm is unsupported in naked functions
LL | | let mut d = 0usize;
| | ------------------- non-asm is unsupported in naked functions
LL | | let mut e = 0usize;
| | ------------------- non-asm is unsupported in naked functions
... |
LL | | );
LL | | }
| |_^
LL | pub unsafe extern "C" fn unsupported_operands() {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL |
LL | let mut a = 0usize;
| ------------------- non-asm is unsupported in naked functions
LL | let mut b = 0usize;
| ------------------- non-asm is unsupported in naked functions
LL | let mut c = 0usize;
| ------------------- non-asm is unsupported in naked functions
LL | let mut d = 0usize;
| ------------------- non-asm is unsupported in naked functions
LL | let mut e = 0usize;
| ------------------- non-asm is unsupported in naked functions

error[E0787]: naked functions must contain a single asm block
--> $DIR/naked-functions.rs:77:1
|
LL | / pub extern "C" fn missing_assembly() {
LL | |
LL | | }
| |_^
LL | pub extern "C" fn missing_assembly() {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0787]: asm in naked functions must use `noreturn` option
--> $DIR/naked-functions.rs:84:5
Expand Down Expand Up @@ -185,20 +177,17 @@ LL | asm!("", options(noreturn));
error[E0787]: naked functions must contain a single asm block
--> $DIR/naked-functions.rs:82:1
|
LL | / pub extern "C" fn too_many_asm_blocks() {
LL | |
LL | | asm!("");
LL | |
LL | | asm!("");
| | -------- multiple asm blocks are unsupported in naked functions
LL | |
LL | | asm!("");
| | -------- multiple asm blocks are unsupported in naked functions
LL | |
LL | | asm!("", options(noreturn));
| | --------------------------- multiple asm blocks are unsupported in naked functions
LL | | }
| |_^
LL | pub extern "C" fn too_many_asm_blocks() {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
LL | asm!("");
| -------- multiple asm blocks are unsupported in naked functions
LL |
LL | asm!("");
| -------- multiple asm blocks are unsupported in naked functions
LL |
LL | asm!("", options(noreturn));
| --------------------------- multiple asm blocks are unsupported in naked functions

error: referencing function parameters is not allowed in naked functions
--> $DIR/naked-functions.rs:97:11
Expand All @@ -211,13 +200,11 @@ LL | *&y
error[E0787]: naked functions must contain a single asm block
--> $DIR/naked-functions.rs:95:5
|
LL | / pub extern "C" fn inner(y: usize) -> usize {
LL | |
LL | | *&y
| | --- non-asm is unsupported in naked functions
LL | |
LL | | }
| |_____^
LL | pub extern "C" fn inner(y: usize) -> usize {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL |
LL | *&y
| --- non-asm is unsupported in naked functions

error[E0787]: asm options unsupported in naked functions: `nomem`, `preserves_flags`
--> $DIR/naked-functions.rs:105:5
Expand Down Expand Up @@ -249,18 +236,18 @@ LL | asm!("", options(noreturn, may_unwind));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: Rust ABI is unsupported in naked functions
--> $DIR/naked-functions.rs:124:15
--> $DIR/naked-functions.rs:124:1
|
LL | pub unsafe fn default_abi() {
| ^^^^^^^^^^^
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(undefined_naked_function_abi)]` on by default

warning: Rust ABI is unsupported in naked functions
--> $DIR/naked-functions.rs:130:15
--> $DIR/naked-functions.rs:130:1
|
LL | pub unsafe fn rust_abi() {
| ^^^^^^^^
| ^^^^^^^^^^^^^^^^^^^^^^^^

error: naked functions cannot be inlined
--> $DIR/naked-functions.rs:170:1
Expand Down

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