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Remove is_terminal_path.

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That information is redundant. Is the path is terminal, `first_child` will
already be `None`.
This commit is contained in:
Camille GILLOT 2023-09-30 17:44:00 +00:00
parent 249624b504
commit a8e56d0b0b
1 changed files with 1 additions and 59 deletions
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60
compiler/rustc_mir_dataflow/src/drop_flag_effects.rs
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@ -1,6 +1,6 @@
use crate::elaborate_drops::DropFlagState;
use rustc_middle::mir::{self, Body, Location, Terminator, TerminatorKind};
use rustc_middle::ty::{self, TyCtxt};
use rustc_middle::ty::TyCtxt;
use rustc_target::abi::VariantIdx;
use super::indexes::MovePathIndex;
@ -55,60 +55,6 @@ pub fn on_all_children_bits<'tcx, F>(
) where
F: FnMut(MovePathIndex),
{
#[inline]
fn is_terminal_path<'tcx>(
tcx: TyCtxt<'tcx>,
body: &Body<'tcx>,
move_data: &MoveData<'tcx>,
path: MovePathIndex,
) -> bool {
let place = move_data.move_paths[path].place;
// When enumerating the child fragments of a path, don't recurse into
// paths (1.) past arrays, slices, and pointers, nor (2.) into a type
// that implements `Drop`.
//
// Places behind references or arrays are not tracked by elaboration
// and are always assumed to be initialized when accessible. As
// references and indexes can be reseated, trying to track them can
// only lead to trouble.
//
// Places behind ADT's with a Drop impl are not tracked by
// elaboration since they can never have a drop-flag state that
// differs from that of the parent with the Drop impl.
//
// In both cases, the contents can only be accessed if and only if
// their parents are initialized. This implies for example that there
// is no need to maintain separate drop flags to track such state.
//
// FIXME: we have to do something for moving slice patterns.
let ty = place.ty(body, tcx).ty;
match ty.kind() {
ty::Adt(def, _) if (def.has_dtor(tcx) && !def.is_box()) || def.is_union() => {
debug!(
"place_contents_drop_state_cannot_differ place: {:?} ty: {:?} Drop => true",
place, ty
);
true
}
ty::Array(..) => {
debug!(
"place_contents_drop_state_cannot_differ place: {:?} ty: {:?} => false",
place, ty
);
false
}
ty::Slice(..) | ty::Ref(..) | ty::RawPtr(..) => {
debug!(
"place_contents_drop_state_cannot_differ place: {:?} ty: {:?} refd => true",
place, ty
);
true
}
_ => false,
}
}
fn on_all_children_bits<'tcx, F>(
tcx: TyCtxt<'tcx>,
body: &Body<'tcx>,
@ -120,10 +66,6 @@ pub fn on_all_children_bits<'tcx, F>(
{
each_child(move_path_index);
if is_terminal_path(tcx, body, move_data, move_path_index) {
return;
}
let mut next_child_index = move_data.move_paths[move_path_index].first_child;
while let Some(child_index) = next_child_index {
on_all_children_bits(tcx, body, move_data, child_index, each_child);