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const_prop_lint: ensure we have up-to-date cur_span()

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This commit is contained in:
Ralf Jung 2022-06-04 15:29:51 -04:00
parent 7892e1cedb
commit 9ab4f876a1
2 changed files with 23 additions and 11 deletions
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5
compiler/rustc_const_eval/src/interpret/eval_context.rs
View File

@ -126,7 +126,9 @@ pub struct Frame<'mir, 'tcx, Tag: Provenance = AllocId, Extra = ()> {
/// this frame (can happen e.g. during frame initialization, and during unwinding on
/// frames without cleanup code).
/// We basically abuse `Result` as `Either`.
pub(super) loc: Result<mir::Location, Span>,
///
/// Needs to be public because ConstProp does unspeakable things to it.
pub loc: Result<mir::Location, Span>,
}
/// What we store about a frame in an interpreter backtrace.
@ -320,6 +322,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> LayoutOfHelpers<'tcx> for InterpC
#[inline]
fn layout_tcx_at_span(&self) -> Span {
// Using the cheap root span for performance.
self.tcx.span
}

29
compiler/rustc_mir_transform/src/const_prop_lint.rs
View File

@ -437,10 +437,12 @@ fn lint_root(&self, source_info: SourceInfo) -> Option<HirId> {
source_info.scope.lint_root(self.source_scopes)
}
fn use_ecx<F, T>(&mut self, f: F) -> Option<T>
fn use_ecx<F, T>(&mut self, source_info: SourceInfo, f: F) -> Option<T>
where
F: FnOnce(&mut Self) -> InterpResult<'tcx, T>,
{
// Overwrite the PC -- whatever the interpreter does to it does not make any sense anyway.
self.ecx.frame_mut().loc = Err(source_info.span);
match f(self) {
Ok(val) => Some(val),
Err(error) => {
@ -501,9 +503,9 @@ fn eval_constant(&mut self, c: &Constant<'tcx>, source_info: SourceInfo) -> Opti
}
/// Returns the value, if any, of evaluating `place`.
fn eval_place(&mut self, place: Place<'tcx>) -> Option<OpTy<'tcx>> {
fn eval_place(&mut self, place: Place<'tcx>, source_info: SourceInfo) -> Option<OpTy<'tcx>> {
trace!("eval_place(place={:?})", place);
self.use_ecx(|this| this.ecx.eval_place_to_op(place, None))
self.use_ecx(source_info, |this| this.ecx.eval_place_to_op(place, None))
}
/// Returns the value, if any, of evaluating `op`. Calls upon `eval_constant`
@ -511,7 +513,7 @@ fn eval_place(&mut self, place: Place<'tcx>) -> Option<OpTy<'tcx>> {
fn eval_operand(&mut self, op: &Operand<'tcx>, source_info: SourceInfo) -> Option<OpTy<'tcx>> {
match *op {
Operand::Constant(ref c) => self.eval_constant(c, source_info),
Operand::Move(place) | Operand::Copy(place) => self.eval_place(place),
Operand::Move(place) | Operand::Copy(place) => self.eval_place(place, source_info),
}
}
@ -537,7 +539,7 @@ fn check_unary_op(
arg: &Operand<'tcx>,
source_info: SourceInfo,
) -> Option<()> {
if let (val, true) = self.use_ecx(|this| {
if let (val, true) = self.use_ecx(source_info, |this| {
let val = this.ecx.read_immediate(&this.ecx.eval_operand(arg, None)?)?;
let (_res, overflow, _ty) = this.ecx.overflowing_unary_op(op, &val)?;
Ok((val, overflow))
@ -564,8 +566,12 @@ fn check_binary_op(
right: &Operand<'tcx>,
source_info: SourceInfo,
) -> Option<()> {
let r = self.use_ecx(|this| this.ecx.read_immediate(&this.ecx.eval_operand(right, None)?));
let l = self.use_ecx(|this| this.ecx.read_immediate(&this.ecx.eval_operand(left, None)?));
let r = self.use_ecx(source_info, |this| {
this.ecx.read_immediate(&this.ecx.eval_operand(right, None)?)
});
let l = self.use_ecx(source_info, |this| {
this.ecx.read_immediate(&this.ecx.eval_operand(left, None)?)
});
// Check for exceeding shifts *even if* we cannot evaluate the LHS.
if op == BinOp::Shr || op == BinOp::Shl {
let r = r?;
@ -602,7 +608,7 @@ fn check_binary_op(
if let (Some(l), Some(r)) = (&l, &r) {
// The remaining operators are handled through `overflowing_binary_op`.
if self.use_ecx(|this| {
if self.use_ecx(source_info, |this| {
let (_res, overflow, _ty) = this.ecx.overflowing_binary_op(op, l, r)?;
Ok(overflow)
})? {
@ -690,7 +696,7 @@ fn const_prop(
return None;
}
self.use_ecx(|this| this.ecx.eval_rvalue_into_place(rvalue, place))
self.use_ecx(source_info, |this| this.ecx.eval_rvalue_into_place(rvalue, place))
}
}
@ -890,7 +896,10 @@ fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
StatementKind::SetDiscriminant { ref place, .. } => {
match self.ecx.machine.can_const_prop[place.local] {
ConstPropMode::FullConstProp | ConstPropMode::OnlyInsideOwnBlock => {
if self.use_ecx(|this| this.ecx.statement(statement)).is_some() {
if self
.use_ecx(source_info, |this| this.ecx.statement(statement))
.is_some()
{
trace!("propped discriminant into {:?}", place);
} else {
Self::remove_const(&mut self.ecx, place.local);