bjoernager/rust
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Add a pointer to address cast kind

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A pointer to address cast are often special-cased.
Introduce a dedicated cast kind to make them easy distinguishable.
This commit is contained in:
Tomasz Miąsko 2022-05-31 00:00:00 +00:00
parent d35d972e69
commit dff602fc18
15 changed files with 96 additions and 94 deletions
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23
compiler/rustc_mir_dataflow/src/impls/liveness.rs
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@ -1,7 +1,6 @@
use rustc_index::bit_set::{BitSet, ChunkedBitSet};
use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor};
use rustc_middle::mir::{self, Local, LocalDecls, Location, Place, StatementKind};
use rustc_middle::ty::TyCtxt;
use rustc_middle::mir::{self, Local, Location, Place, StatementKind};
use crate::{Analysis, AnalysisDomain, Backward, CallReturnPlaces, GenKill, GenKillAnalysis};
@ -193,27 +192,21 @@ impl DefUse {
/// This is basically written for dead store elimination and nothing else.
///
/// All of the caveats of `MaybeLiveLocals` apply.
pub struct MaybeTransitiveLiveLocals<'a, 'tcx> {
pub struct MaybeTransitiveLiveLocals<'a> {
always_live: &'a BitSet<Local>,
local_decls: &'a LocalDecls<'tcx>,
tcx: TyCtxt<'tcx>,
}
impl<'a, 'tcx> MaybeTransitiveLiveLocals<'a, 'tcx> {
impl<'a> MaybeTransitiveLiveLocals<'a> {
/// The `always_alive` set is the set of locals to which all stores should unconditionally be
/// considered live.
///
/// This should include at least all locals that are ever borrowed.
pub fn new(
always_live: &'a BitSet<Local>,
local_decls: &'a LocalDecls<'tcx>,
tcx: TyCtxt<'tcx>,
) -> Self {
MaybeTransitiveLiveLocals { always_live, local_decls, tcx }
pub fn new(always_live: &'a BitSet<Local>) -> Self {
MaybeTransitiveLiveLocals { always_live }
}
}
impl<'a, 'tcx> AnalysisDomain<'tcx> for MaybeTransitiveLiveLocals<'a, 'tcx> {
impl<'a, 'tcx> AnalysisDomain<'tcx> for MaybeTransitiveLiveLocals<'a> {
type Domain = ChunkedBitSet<Local>;
type Direction = Backward;
@ -241,7 +234,7 @@ impl<'a> GenKill<Local> for TransferWrapper<'a> {
}
}
impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a, 'tcx> {
impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
fn apply_statement_effect(
&self,
trans: &mut Self::Domain,
@ -251,7 +244,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a, 'tcx> {
// Compute the place that we are storing to, if any
let destination = match &statement.kind {
StatementKind::Assign(assign) => {
if assign.1.is_pointer_int_cast(self.local_decls, self.tcx) {
if assign.1.is_pointer_int_cast() {
// Pointer to int casts may be side-effects due to exposing the provenance.
// While the model is undecided, we should be conservative. See
// <https://www.ralfj.de/blog/2022/04/11/provenance-exposed.html>