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Rollup merge of #95196 - RalfJung:unalloc-not-uninit, r=oli-obk

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rename LocalState::Uninitialized to Unallocated

This is to avoid confusion with `Uninit` as in `ScalarMaybeUninit`, which is very different.

r? `@oli-obk`
This commit is contained in:
Dylan DPC 2022-03-22 19:07:34 +01:00 committed by GitHub
parent 7c38093951 b92a60586a
commit 0e59ad4ce3
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 14 additions and 16 deletions
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22
compiler/rustc_const_eval/src/interpret/eval_context.rs
View file

@ -177,11 +177,10 @@ pub struct LocalState<'tcx, Tag: Provenance = AllocId> {
pub enum LocalValue<Tag: Provenance = AllocId> {
/// This local is not currently alive, and cannot be used at all.
Dead,
/// This local is alive but not yet initialized. It can be written to
/// but not read from or its address taken. Locals get initialized on
/// first write because for unsized locals, we do not know their size
/// before that.
Uninitialized,
/// This local is alive but not yet allocated. It cannot be read from or have its address taken,
/// and will be allocated on the first write. This is to support unsized locals, where we cannot
/// know their size in advance.
Unallocated,
/// A normal, live local.
/// Mostly for convenience, we re-use the `Operand` type here.
/// This is an optimization over just always having a pointer here;
@ -198,7 +197,7 @@ impl<'tcx, Tag: Provenance + 'static> LocalState<'tcx, Tag> {
pub fn access(&self) -> InterpResult<'tcx, Operand<Tag>> {
match self.value {
LocalValue::Dead => throw_ub!(DeadLocal),
LocalValue::Uninitialized => {
LocalValue::Unallocated => {
bug!("The type checker should prevent reading from a never-written local")
}
LocalValue::Live(val) => Ok(val),
@ -216,8 +215,7 @@ impl<'tcx, Tag: Provenance + 'static> LocalState<'tcx, Tag> {
match self.value {
LocalValue::Dead => throw_ub!(DeadLocal),
LocalValue::Live(Operand::Indirect(mplace)) => Ok(Err(mplace)),
ref mut
local @ (LocalValue::Live(Operand::Immediate(_)) | LocalValue::Uninitialized) => {
ref mut local @ (LocalValue::Live(Operand::Immediate(_)) | LocalValue::Unallocated) => {
Ok(Ok(local))
}
}
@ -752,8 +750,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
})?;
}
// Locals are initially uninitialized.
let dummy = LocalState { value: LocalValue::Uninitialized, layout: Cell::new(None) };
// Locals are initially unallocated.
let dummy = LocalState { value: LocalValue::Unallocated, layout: Cell::new(None) };
let mut locals = IndexVec::from_elem(dummy, &body.local_decls);
// Now mark those locals as dead that we do not want to initialize
@ -921,7 +919,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
assert!(local != mir::RETURN_PLACE, "Cannot make return place live");
trace!("{:?} is now live", local);
let local_val = LocalValue::Uninitialized;
let local_val = LocalValue::Unallocated;
// StorageLive expects the local to be dead, and marks it live.
let old = mem::replace(&mut self.frame_mut().locals[local].value, local_val);
if !matches!(old, LocalValue::Dead) {
@ -1025,7 +1023,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> std::fmt::Debug
match self.ecx.stack()[frame].locals[local].value {
LocalValue::Dead => write!(fmt, " is dead")?,
LocalValue::Uninitialized => write!(fmt, " is uninitialized")?,
LocalValue::Unallocated => write!(fmt, " is unallocated")?,
LocalValue::Live(Operand::Indirect(mplace)) => {
write!(
fmt,

8
compiler/rustc_mir_transform/src/const_prop.rs
View file

@ -244,8 +244,8 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine<'mir, 'tcx>
) -> InterpResult<'tcx, InterpOperand<Self::PointerTag>> {
let l = &frame.locals[local];
if l.value == LocalValue::Uninitialized {
throw_machine_stop_str!("tried to access an uninitialized local")
if l.value == LocalValue::Unallocated {
throw_machine_stop_str!("tried to access an unallocated local")
}
l.access()
@ -442,7 +442,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
/// but not reading from them anymore.
fn remove_const(ecx: &mut InterpCx<'mir, 'tcx, ConstPropMachine<'mir, 'tcx>>, local: Local) {
ecx.frame_mut().locals[local] =
LocalState { value: LocalValue::Uninitialized, layout: Cell::new(None) };
LocalState { value: LocalValue::Unallocated, layout: Cell::new(None) };
}
fn lint_root(&self, source_info: SourceInfo) -> Option<HirId> {
@ -1147,7 +1147,7 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
let frame = self.ecx.frame_mut();
frame.locals[local].value =
if let StatementKind::StorageLive(_) = statement.kind {
LocalValue::Uninitialized
LocalValue::Unallocated
} else {
LocalValue::Dead
};