bjoernager/rust
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Refactor tracking of writes.

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This commit is contained in:
Camille GILLOT 2023-03-07 15:20:57 +00:00
parent 9928d0e566
commit d97a7ce69b
2 changed files with 58 additions and 72 deletions
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48
compiler/rustc_mir_transform/src/const_prop_lint.rs
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@ -9,7 +9,6 @@ use rustc_const_eval::interpret::{
};
use rustc_hir::def::DefKind;
use rustc_hir::HirId;
use rustc_index::bit_set::BitSet;
use rustc_index::vec::IndexVec;
use rustc_middle::mir::visit::Visitor;
use rustc_middle::mir::*;
@ -179,17 +178,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
let param_env = tcx.param_env_reveal_all_normalized(def_id);
let can_const_prop = CanConstProp::check(tcx, param_env, body);
let mut only_propagate_inside_block_locals = BitSet::new_empty(can_const_prop.len());
for (l, mode) in can_const_prop.iter_enumerated() {
if *mode == ConstPropMode::OnlyInsideOwnBlock {
only_propagate_inside_block_locals.insert(l);
}
}
let mut ecx = InterpCx::new(
tcx,
tcx.def_span(def_id),
param_env,
ConstPropMachine::new(only_propagate_inside_block_locals, can_const_prop),
ConstPropMachine::new(can_const_prop),
);
let ret_layout = ecx
@ -687,26 +680,33 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
fn visit_basic_block_data(&mut self, block: BasicBlock, data: &BasicBlockData<'tcx>) {
self.super_basic_block_data(block, data);
let ensure_not_propagated = |this: &mut Self, local: Local| {
if cfg!(debug_assertions) {
assert!(
this.get_const(local.into()).is_none()
|| this
.layout_of(this.local_decls[local].ty)
.map_or(true, |layout| layout.is_zst()),
"failed to remove values for `{local:?}`, value={:?}",
this.get_const(local.into()),
)
}
};
// We remove all Locals which are restricted in propagation to their containing blocks and
// which were modified in the current block.
// Take it out of the ecx so we can get a mutable reference to the ecx for `remove_const`.
let mut locals = std::mem::take(&mut self.ecx.machine.written_only_inside_own_block_locals);
for &local in locals.iter() {
Self::remove_const(&mut self.ecx, local);
}
locals.clear();
// Put it back so we reuse the heap of the storage
self.ecx.machine.written_only_inside_own_block_locals = locals;
if cfg!(debug_assertions) {
// Ensure we are correctly erasing locals with the non-debug-assert logic.
for local in self.ecx.machine.only_propagate_inside_block_locals.iter() {
assert!(
self.get_const(local.into()).is_none()
|| self
.layout_of(self.local_decls[local].ty)
.map_or(true, |layout| layout.is_zst())
)
let can_const_prop = std::mem::take(&mut self.ecx.machine.can_const_prop);
for (local, &mode) in can_const_prop.iter_enumerated() {
match mode {
ConstPropMode::FullConstProp => {}
ConstPropMode::NoPropagation => ensure_not_propagated(self, local),
ConstPropMode::OnlyInsideOwnBlock => {
Self::remove_const(&mut self.ecx, local);
ensure_not_propagated(self, local);
}
}
}
self.ecx.machine.can_const_prop = can_const_prop;
}
}