Skip to content

Commit

Permalink
Rollup merge of rust-lang#77343 - varkor:rustc_args_required_const-va…
Browse files Browse the repository at this point in the history
…lidation, r=lcnr

Validate `rustc_args_required_const`

Fixes rust-lang#74608.
  • Loading branch information
Dylan-DPC authored Oct 1, 2020
2 parents 73258f8 + 609786d commit 849e563
Show file tree
Hide file tree
Showing 4 changed files with 176 additions and 10 deletions.
2 changes: 1 addition & 1 deletion compiler/rustc_mir/src/transform/promote_consts.rs
Original file line number Diff line number Diff line change
Expand Up @@ -137,7 +137,7 @@ fn args_required_const(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Vec<usize>> {
LitKind::Int(a, _) => {
ret.push(a as usize);
}
_ => return None,
_ => bug!("invalid arg index"),
}
}
Some(ret)
Expand Down
110 changes: 101 additions & 9 deletions compiler/rustc_passes/src/check_attr.rs
Original file line number Diff line number Diff line change
Expand Up @@ -8,12 +8,12 @@ use rustc_middle::hir::map::Map;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::TyCtxt;

use rustc_ast::{Attribute, NestedMetaItem};
use rustc_errors::struct_span_err;
use rustc_ast::{Attribute, LitKind, NestedMetaItem};
use rustc_errors::{pluralize, struct_span_err};
use rustc_hir as hir;
use rustc_hir::def_id::LocalDefId;
use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
use rustc_hir::{self, HirId, Item, ItemKind, TraitItem};
use rustc_hir::{self, FnSig, ForeignItem, ForeignItemKind, HirId, Item, ItemKind, TraitItem};
use rustc_hir::{MethodKind, Target};
use rustc_session::lint::builtin::{CONFLICTING_REPR_HINTS, UNUSED_ATTRIBUTES};
use rustc_session::parse::feature_err;
Expand Down Expand Up @@ -43,6 +43,12 @@ pub(crate) fn target_from_impl_item<'tcx>(
}
}

#[derive(Clone, Copy)]
enum ItemLike<'tcx> {
Item(&'tcx Item<'tcx>),
ForeignItem(&'tcx ForeignItem<'tcx>),
}

struct CheckAttrVisitor<'tcx> {
tcx: TyCtxt<'tcx>,
}
Expand All @@ -55,7 +61,7 @@ impl CheckAttrVisitor<'tcx> {
attrs: &'hir [Attribute],
span: &Span,
target: Target,
item: Option<&Item<'_>>,
item: Option<ItemLike<'_>>,
) {
let mut is_valid = true;
for attr in attrs {
Expand All @@ -75,6 +81,8 @@ impl CheckAttrVisitor<'tcx> {
self.check_no_link(&attr, span, target)
} else if self.tcx.sess.check_name(attr, sym::export_name) {
self.check_export_name(&attr, span, target)
} else if self.tcx.sess.check_name(attr, sym::rustc_args_required_const) {
self.check_rustc_args_required_const(&attr, span, target, item)
} else {
// lint-only checks
if self.tcx.sess.check_name(attr, sym::cold) {
Expand Down Expand Up @@ -400,6 +408,71 @@ impl CheckAttrVisitor<'tcx> {
}
}

/// Checks if `#[rustc_args_required_const]` is applied to a function and has a valid argument.
fn check_rustc_args_required_const(
&self,
attr: &Attribute,
span: &Span,
target: Target,
item: Option<ItemLike<'_>>,
) -> bool {
if let Target::Fn | Target::Method(..) | Target::ForeignFn = target {
let mut invalid_args = vec![];
for meta in attr.meta_item_list().expect("no meta item list") {
if let Some(LitKind::Int(val, _)) = meta.literal().map(|lit| &lit.kind) {
if let Some(ItemLike::Item(Item {
kind: ItemKind::Fn(FnSig { decl, .. }, ..),
..
}))
| Some(ItemLike::ForeignItem(ForeignItem {
kind: ForeignItemKind::Fn(decl, ..),
..
})) = item
{
let arg_count = decl.inputs.len() as u128;
if *val >= arg_count {
let span = meta.span();
self.tcx
.sess
.struct_span_err(span, "index exceeds number of arguments")
.span_label(
span,
format!(
"there {} only {} argument{}",
if arg_count != 1 { "are" } else { "is" },
arg_count,
pluralize!(arg_count)
),
)
.emit();
return false;
}
} else {
bug!("should be a function item");
}
} else {
invalid_args.push(meta.span());
}
}
if !invalid_args.is_empty() {
self.tcx
.sess
.struct_span_err(invalid_args, "arguments should be non-negative integers")
.emit();
false
} else {
true
}
} else {
self.tcx
.sess
.struct_span_err(attr.span, "attribute should be applied to a function")
.span_label(*span, "not a function")
.emit();
false
}
}

/// Checks if `#[link_section]` is applied to a function or static.
fn check_link_section(&self, hir_id: HirId, attr: &Attribute, span: &Span, target: Target) {
match target {
Expand Down Expand Up @@ -448,7 +521,7 @@ impl CheckAttrVisitor<'tcx> {
attrs: &'hir [Attribute],
span: &Span,
target: Target,
item: Option<&Item<'_>>,
item: Option<ItemLike<'_>>,
hir_id: HirId,
) {
// Extract the names of all repr hints, e.g., [foo, bar, align] for:
Expand Down Expand Up @@ -564,7 +637,14 @@ impl CheckAttrVisitor<'tcx> {
// Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
if (int_reprs > 1)
|| (is_simd && is_c)
|| (int_reprs == 1 && is_c && item.map_or(false, |item| is_c_like_enum(item)))
|| (int_reprs == 1
&& is_c
&& item.map_or(false, |item| {
if let ItemLike::Item(item) = item {
return is_c_like_enum(item);
}
return false;
}))
{
self.tcx.struct_span_lint_hir(
CONFLICTING_REPR_HINTS,
Expand Down Expand Up @@ -649,7 +729,13 @@ impl Visitor<'tcx> for CheckAttrVisitor<'tcx> {

fn visit_item(&mut self, item: &'tcx Item<'tcx>) {
let target = Target::from_item(item);
self.check_attributes(item.hir_id, item.attrs, &item.span, target, Some(item));
self.check_attributes(
item.hir_id,
item.attrs,
&item.span,
target,
Some(ItemLike::Item(item)),
);
intravisit::walk_item(self, item)
}

Expand All @@ -659,9 +745,15 @@ impl Visitor<'tcx> for CheckAttrVisitor<'tcx> {
intravisit::walk_trait_item(self, trait_item)
}

fn visit_foreign_item(&mut self, f_item: &'tcx hir::ForeignItem<'tcx>) {
fn visit_foreign_item(&mut self, f_item: &'tcx ForeignItem<'tcx>) {
let target = Target::from_foreign_item(f_item);
self.check_attributes(f_item.hir_id, &f_item.attrs, &f_item.span, target, None);
self.check_attributes(
f_item.hir_id,
&f_item.attrs,
&f_item.span,
target,
Some(ItemLike::ForeignItem(f_item)),
);
intravisit::walk_foreign_item(self, f_item)
}

Expand Down
26 changes: 26 additions & 0 deletions src/test/ui/invalid-rustc_args_required_const-arguments.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
#![feature(rustc_attrs)]

#[rustc_args_required_const(0)] //~ ERROR index exceeds number of arguments
fn foo1() {}

#[rustc_args_required_const(1)] //~ ERROR index exceeds number of arguments
fn foo2(_: u8) {}

#[rustc_args_required_const(a)] //~ ERROR arguments should be non-negative integers
fn foo4() {}

#[rustc_args_required_const(1, a, 2, b)] //~ ERROR arguments should be non-negative integers
fn foo5(_: u8, _: u8, _: u8) {}

#[rustc_args_required_const(0)] //~ ERROR attribute should be applied to a function
struct S;

#[rustc_args_required_const(0usize)] //~ ERROR suffixed literals are not allowed in attributes
fn foo6(_: u8) {}

extern {
#[rustc_args_required_const(1)] //~ ERROR index exceeds number of arguments
fn foo7(_: u8);
}

fn main() {}
48 changes: 48 additions & 0 deletions src/test/ui/invalid-rustc_args_required_const-arguments.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,48 @@
error: suffixed literals are not allowed in attributes
--> $DIR/invalid-rustc_args_required_const-arguments.rs:18:29
|
LL | #[rustc_args_required_const(0usize)]
| ^^^^^^
|
= help: instead of using a suffixed literal (`1u8`, `1.0f32`, etc.), use an unsuffixed version (`1`, `1.0`, etc.)

error: index exceeds number of arguments
--> $DIR/invalid-rustc_args_required_const-arguments.rs:3:29
|
LL | #[rustc_args_required_const(0)]
| ^ there are only 0 arguments

error: index exceeds number of arguments
--> $DIR/invalid-rustc_args_required_const-arguments.rs:6:29
|
LL | #[rustc_args_required_const(1)]
| ^ there is only 1 argument

error: arguments should be non-negative integers
--> $DIR/invalid-rustc_args_required_const-arguments.rs:9:29
|
LL | #[rustc_args_required_const(a)]
| ^

error: arguments should be non-negative integers
--> $DIR/invalid-rustc_args_required_const-arguments.rs:12:32
|
LL | #[rustc_args_required_const(1, a, 2, b)]
| ^ ^

error: attribute should be applied to a function
--> $DIR/invalid-rustc_args_required_const-arguments.rs:15:1
|
LL | #[rustc_args_required_const(0)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | struct S;
| --------- not a function

error: index exceeds number of arguments
--> $DIR/invalid-rustc_args_required_const-arguments.rs:22:33
|
LL | #[rustc_args_required_const(1)]
| ^ there is only 1 argument

error: aborting due to 7 previous errors

0 comments on commit 849e563

Please sign in to comment.