New upstream version 1.57.0+dfsg1

[rustc.git] / compiler / rustc_mir / src / transform / check_packed_ref.rs

diff --git a/compiler/rustc_mir/src/transform/check_packed_ref.rs b/compiler/rustc_mir/src/transform/check_packed_ref.rs
deleted file mode 100644 (file)
index 13b7221..0000000
--- a/compiler/rustc_mir/src/transform/check_packed_ref.rs
+++ /dev/null
@@ -1,115 +0,0 @@
-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 {
-    fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        let param_env = tcx.param_env(body.source.def_id());
-        let source_info = SourceInfo::outermost(body.span);
-        let mut checker = PackedRefChecker { body, tcx, param_env, source_info };
-        checker.visit_body(&body);
-    }
-}
-
-struct PackedRefChecker<'a, 'tcx> {
-    body: &'a Body<'tcx>,
-    tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'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.
-        self.source_info = terminator.source_info;
-        self.super_terminator(terminator, location);
-    }
-
-    fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
-        // Make sure we know where in the MIR we are.
-        self.source_info = statement.source_info;
-        self.super_statement(statement, location);
-    }
-
-    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 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()
-                        },
-                    );
-                }
-            }
-        }
-    }
-}