diff options
Diffstat (limited to 'compiler/rustc_mir_transform/src/check_packed_ref.rs')
-rw-r--r-- | compiler/rustc_mir_transform/src/check_packed_ref.rs | 88 |
1 files changed, 23 insertions, 65 deletions
diff --git a/compiler/rustc_mir_transform/src/check_packed_ref.rs b/compiler/rustc_mir_transform/src/check_packed_ref.rs index 51abcf511..f5f1c1010 100644 --- a/compiler/rustc_mir_transform/src/check_packed_ref.rs +++ b/compiler/rustc_mir_transform/src/check_packed_ref.rs @@ -1,17 +1,11 @@ -use rustc_hir::def_id::LocalDefId; +use rustc_errors::struct_span_err; 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 crate::util; use crate::MirLint; -pub(crate) fn provide(providers: &mut Providers) { - *providers = Providers { unsafe_derive_on_repr_packed, ..*providers }; -} - pub struct CheckPackedRef; impl<'tcx> MirLint<'tcx> for CheckPackedRef { @@ -30,32 +24,6 @@ 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); - - // FIXME: when we make this a hard error, this should have its - // own error code. - - let extra = if tcx.generics_of(def_id).own_requires_monomorphization() { - "with type or const parameters" - } else { - "that does not derive `Copy`" - }; - let message = format!( - "`{}` can't be derived on this `#[repr(packed)]` struct {}", - tcx.item_name(tcx.trait_id_of_impl(def_id.to_def_id()).expect("derived trait name")), - extra - ); - - tcx.struct_span_lint_hir( - UNALIGNED_REFERENCES, - lint_hir_id, - tcx.def_span(def_id), - message, - |lint| lint, - ); -} - impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> { fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) { // Make sure we know where in the MIR we are. @@ -73,40 +41,30 @@ impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> { if context.is_borrow() { if util::is_disaligned(self.tcx, self.body, self.param_env, *place) { let def_id = self.body.source.instance.def_id(); - if let Some(impl_def_id) = self - .tcx - .impl_of_method(def_id) - .filter(|&def_id| self.tcx.is_builtin_derive(def_id)) + if let Some(impl_def_id) = self.tcx.impl_of_method(def_id) + && self.tcx.is_builtin_derived(impl_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()); + // If we ever reach here it means that the generated derive + // code is somehow doing an unaligned reference, which it + // shouldn't do. + span_bug!(self.source_info.span, "builtin derive created an unaligned reference"); } 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, - "reference to packed field is unaligned", - |lint| { - lint - .note( - "fields of packed structs are not properly aligned, and creating \ - a misaligned reference is undefined behavior (even if that \ - reference is never dereferenced)", - ) - .help( - "copy the field contents to a local variable, or replace the \ - reference with a raw pointer and use `read_unaligned`/`write_unaligned` \ - (loads and stores via `*p` must be properly aligned even when using raw pointers)" - ) - }, - ); + struct_span_err!( + self.tcx.sess, + self.source_info.span, + E0793, + "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)", + ).help( + "copy the field contents to a local variable, or replace the \ + reference with a raw pointer and use `read_unaligned`/`write_unaligned` \ + (loads and stores via `*p` must be properly aligned even when using raw pointers)" + ) + .emit(); } } } |