rust-lang/rust
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

make unaligned_refereces future-incompat lint warn-by-default, and remove the safe_packed_borrows lint that it replaces

Browse Source
This commit is contained in:
Ralf Jung
2021-02-25 19:38:53 +01:00
parent f811f14006
commit fb4f48e032
25 changed files with 251 additions and 415 deletions
Download Patch File Download Diff File Expand all files Collapse all files

89
compiler/rustc_mir/src/transform/check_packed_ref.rs
View File

@@ -1,11 +1,18 @@
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_middle::mir::visit::{PlaceContext, Visitor};
use rustc_middle::mir::*;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::{self, TyCtxt};
use rustc_session::lint::builtin::UNALIGNED_REFERENCES;
use rustc_span::symbol::sym;
use crate::transform::MirPass;
use crate::util;
pub(crate) fn provide(providers: &mut Providers) {
*providers = Providers { unsafe_derive_on_repr_packed, ..*providers };
}
pub struct CheckPackedRef;
impl<'tcx> MirPass<'tcx> for CheckPackedRef {
@@ -24,6 +31,41 @@ struct PackedRefChecker<'a, 'tcx> {
source_info: SourceInfo,
}
fn unsafe_derive_on_repr_packed(tcx: TyCtxt<'_>, def_id: LocalDefId) {
let lint_hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
tcx.struct_span_lint_hir(UNALIGNED_REFERENCES, lint_hir_id, tcx.def_span(def_id), |lint| {
// FIXME: when we make this a hard error, this should have its
// own error code.
let message = if tcx.generics_of(def_id).own_requires_monomorphization() {
"`#[derive]` can't be used on a `#[repr(packed)]` struct with \
type or const parameters (error E0133)"
.to_string()
} else {
"`#[derive]` can't be used on a `#[repr(packed)]` struct that \
does not derive Copy (error E0133)"
.to_string()
};
lint.build(&message).emit()
});
}
fn builtin_derive_def_id(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
debug!("builtin_derive_def_id({:?})", def_id);
if let Some(impl_def_id) = tcx.impl_of_method(def_id) {
if tcx.has_attr(impl_def_id, sym::automatically_derived) {
debug!("builtin_derive_def_id({:?}) - is {:?}", def_id, impl_def_id);
Some(impl_def_id)
} else {
debug!("builtin_derive_def_id({:?}) - not automatically derived", def_id);
None
}
} else {
debug!("builtin_derive_def_id({:?}) - not a method", def_id);
None
}
}
impl<'a, 'tcx> Visitor<'tcx> for PackedRefChecker<'a, 'tcx> {
fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
// Make sure we know where in the MIR we are.
@@ -40,26 +82,33 @@ impl<'a, 'tcx> Visitor<'tcx> for PackedRefChecker<'a, 'tcx> {
fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, _location: Location) {
if context.is_borrow() {
if util::is_disaligned(self.tcx, self.body, self.param_env, *place) {
let source_info = self.source_info;
let lint_root = self.body.source_scopes[source_info.scope]
.local_data
.as_ref()
.assert_crate_local()
.lint_root;
self.tcx.struct_span_lint_hir(
UNALIGNED_REFERENCES,
lint_root,
source_info.span,
|lint| {
lint.build("reference to packed field is unaligned")
.note(
"fields of packed structs are not properly aligned, and creating \
a misaligned reference is undefined behavior (even if that \
reference is never dereferenced)",
)
.emit()
},
);
let def_id = self.body.source.instance.def_id();
if let Some(impl_def_id) = builtin_derive_def_id(self.tcx, def_id) {
// If a method is defined in the local crate,
// the impl containing that method should also be.
self.tcx.ensure().unsafe_derive_on_repr_packed(impl_def_id.expect_local());
} else {
let source_info = self.source_info;
let lint_root = self.body.source_scopes[source_info.scope]
.local_data
.as_ref()
.assert_crate_local()
.lint_root;
self.tcx.struct_span_lint_hir(
UNALIGNED_REFERENCES,
lint_root,
source_info.span,
|lint| {
lint.build("reference to packed field is unaligned")
.note(
"fields of packed structs are not properly aligned, and creating \
a misaligned reference is undefined behavior (even if that \
reference is never dereferenced)",
)
.emit()
},
);
}
}
}
}