bjoernager/rust
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Replace a magic boolean with enum ScheduleDrops

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This commit is contained in:
Zalathar 2024-06-26 13:44:25 +10:00
parent 3b22589cfa
commit ed07712e96
2 changed files with 56 additions and 18 deletions
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18
compiler/rustc_mir_build/src/build/block.rs
View file

@ -1,4 +1,4 @@
use crate::build::matches::{DeclareLetBindings, EmitStorageLive}; use crate::build::matches::{DeclareLetBindings, EmitStorageLive, ScheduleDrops};
use crate::build::ForGuard::OutsideGuard; use crate::build::ForGuard::OutsideGuard;
use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder}; use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
use rustc_middle::middle::region::Scope; use rustc_middle::middle::region::Scope;
@ -202,7 +202,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
pattern, pattern,
UserTypeProjections::none(), UserTypeProjections::none(),
&mut |this, _, _, node, span, _, _| { &mut |this, _, _, node, span, _, _| {
this.storage_live_binding(block, node, span, OutsideGuard, true); this.storage_live_binding(
block,
node,
span,
OutsideGuard,
ScheduleDrops::Yes,
);
}, },
); );
let else_block_span = this.thir[*else_block].span; let else_block_span = this.thir[*else_block].span;
@ -292,7 +298,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
pattern, pattern,
UserTypeProjections::none(), UserTypeProjections::none(),
&mut |this, _, _, node, span, _, _| { &mut |this, _, _, node, span, _, _| {
this.storage_live_binding(block, node, span, OutsideGuard, true); this.storage_live_binding(
block,
node,
span,
OutsideGuard,
ScheduleDrops::Yes,
);
this.schedule_drop_for_binding(node, span, OutsideGuard); this.schedule_drop_for_binding(node, span, OutsideGuard);
}, },
) )

56
compiler/rustc_mir_build/src/build/matches/mod.rs
View file

@ -28,6 +28,7 @@ mod simplify;
mod test; mod test;
mod util; mod util;
use std::assert_matches::assert_matches;
use std::borrow::Borrow; use std::borrow::Borrow;
use std::mem; use std::mem;
@ -74,6 +75,17 @@ pub(crate) enum EmitStorageLive {
No, No,
} }
/// Used by [`Builder::storage_live_binding`] and [`Builder::bind_matched_candidate_for_arm_body`]
/// to decide whether to schedule drops.
#[derive(Clone, Copy, Debug)]
pub(crate) enum ScheduleDrops {
/// Yes, the relevant functions should also schedule drops as appropriate.
Yes,
/// No, don't schedule drops. The caller has taken responsibility for any
/// appropriate drops.
No,
}
impl<'a, 'tcx> Builder<'a, 'tcx> { impl<'a, 'tcx> Builder<'a, 'tcx> {
/// Lowers a condition in a way that ensures that variables bound in any let /// Lowers a condition in a way that ensures that variables bound in any let
/// expressions are definitely initialized in the if body. /// expressions are definitely initialized in the if body.
@ -535,7 +547,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
fake_borrow_temps, fake_borrow_temps,
scrutinee_span, scrutinee_span,
arm_match_scope, arm_match_scope,
true, ScheduleDrops::Yes,
emit_storage_live, emit_storage_live,
) )
} else { } else {
@ -554,7 +566,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
// To handle this we instead unschedule it's drop after each time // To handle this we instead unschedule it's drop after each time
// we lower the guard. // we lower the guard.
let target_block = self.cfg.start_new_block(); let target_block = self.cfg.start_new_block();
let mut schedule_drops = true; let mut schedule_drops = ScheduleDrops::Yes;
let arm = arm_match_scope.unzip().0; let arm = arm_match_scope.unzip().0;
// We keep a stack of all of the bindings and type ascriptions // We keep a stack of all of the bindings and type ascriptions
// from the parent candidates that we visit, that also need to // from the parent candidates that we visit, that also need to
@ -576,7 +588,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
emit_storage_live, emit_storage_live,
); );
if arm.is_none() { if arm.is_none() {
schedule_drops = false; schedule_drops = ScheduleDrops::No;
} }
self.cfg.goto(binding_end, outer_source_info, target_block); self.cfg.goto(binding_end, outer_source_info, target_block);
}, },
@ -602,8 +614,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
match irrefutable_pat.kind { match irrefutable_pat.kind {
// Optimize the case of `let x = ...` to write directly into `x` // Optimize the case of `let x = ...` to write directly into `x`
PatKind::Binding { mode: BindingMode(ByRef::No, _), var, subpattern: None, .. } => { PatKind::Binding { mode: BindingMode(ByRef::No, _), var, subpattern: None, .. } => {
let place = let place = self.storage_live_binding(
self.storage_live_binding(block, var, irrefutable_pat.span, OutsideGuard, true); block,
var,
irrefutable_pat.span,
OutsideGuard,
ScheduleDrops::Yes,
);
unpack!(block = self.expr_into_dest(place, block, initializer_id)); unpack!(block = self.expr_into_dest(place, block, initializer_id));
// Inject a fake read, see comments on `FakeReadCause::ForLet`. // Inject a fake read, see comments on `FakeReadCause::ForLet`.
@ -636,8 +653,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}, },
ascription: thir::Ascription { ref annotation, variance: _ }, ascription: thir::Ascription { ref annotation, variance: _ },
} => { } => {
let place = let place = self.storage_live_binding(
self.storage_live_binding(block, var, irrefutable_pat.span, OutsideGuard, true); block,
var,
irrefutable_pat.span,
OutsideGuard,
ScheduleDrops::Yes,
);
unpack!(block = self.expr_into_dest(place, block, initializer_id)); unpack!(block = self.expr_into_dest(place, block, initializer_id));
// Inject a fake read, see comments on `FakeReadCause::ForLet`. // Inject a fake read, see comments on `FakeReadCause::ForLet`.
@ -827,7 +849,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
var: LocalVarId, var: LocalVarId,
span: Span, span: Span,
for_guard: ForGuard, for_guard: ForGuard,
schedule_drop: bool, schedule_drop: ScheduleDrops,
) -> Place<'tcx> { ) -> Place<'tcx> {
let local_id = self.var_local_id(var, for_guard); let local_id = self.var_local_id(var, for_guard);
let source_info = self.source_info(span); let source_info = self.source_info(span);
@ -835,7 +857,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
// Although there is almost always scope for given variable in corner cases // Although there is almost always scope for given variable in corner cases
// like #92893 we might get variable with no scope. // like #92893 we might get variable with no scope.
if let Some(region_scope) = self.region_scope_tree.var_scope(var.0.local_id) if let Some(region_scope) = self.region_scope_tree.var_scope(var.0.local_id)
&& schedule_drop && matches!(schedule_drop, ScheduleDrops::Yes)
{ {
self.schedule_drop(span, region_scope, local_id, DropKind::Storage); self.schedule_drop(span, region_scope, local_id, DropKind::Storage);
} }
@ -2112,7 +2134,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
fake_borrows: &[(Place<'tcx>, Local, FakeBorrowKind)], fake_borrows: &[(Place<'tcx>, Local, FakeBorrowKind)],
scrutinee_span: Span, scrutinee_span: Span,
arm_match_scope: Option<(&Arm<'tcx>, region::Scope)>, arm_match_scope: Option<(&Arm<'tcx>, region::Scope)>,
schedule_drops: bool, schedule_drops: ScheduleDrops,
emit_storage_live: EmitStorageLive, emit_storage_live: EmitStorageLive,
) -> BasicBlock { ) -> BasicBlock {
debug!("bind_and_guard_matched_candidate(candidate={:?})", candidate); debug!("bind_and_guard_matched_candidate(candidate={:?})", candidate);
@ -2323,10 +2345,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let cause = FakeReadCause::ForGuardBinding; let cause = FakeReadCause::ForGuardBinding;
self.cfg.push_fake_read(post_guard_block, guard_end, cause, Place::from(local_id)); self.cfg.push_fake_read(post_guard_block, guard_end, cause, Place::from(local_id));
} }
assert!(schedule_drops, "patterns with guards must schedule drops"); assert_matches!(
schedule_drops,
ScheduleDrops::Yes,
"patterns with guards must schedule drops"
);
self.bind_matched_candidate_for_arm_body( self.bind_matched_candidate_for_arm_body(
post_guard_block, post_guard_block,
true, ScheduleDrops::Yes,
by_value_bindings, by_value_bindings,
emit_storage_live, emit_storage_live,
); );
@ -2376,7 +2402,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
fn bind_matched_candidate_for_guard<'b>( fn bind_matched_candidate_for_guard<'b>(
&mut self, &mut self,
block: BasicBlock, block: BasicBlock,
schedule_drops: bool, schedule_drops: ScheduleDrops,
bindings: impl IntoIterator<Item = &'b Binding<'tcx>>, bindings: impl IntoIterator<Item = &'b Binding<'tcx>>,
) where ) where
'tcx: 'b, 'tcx: 'b,
@ -2429,7 +2455,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
fn bind_matched_candidate_for_arm_body<'b>( fn bind_matched_candidate_for_arm_body<'b>(
&mut self, &mut self,
block: BasicBlock, block: BasicBlock,
schedule_drops: bool, schedule_drops: ScheduleDrops,
bindings: impl IntoIterator<Item = &'b Binding<'tcx>>, bindings: impl IntoIterator<Item = &'b Binding<'tcx>>,
emit_storage_live: EmitStorageLive, emit_storage_live: EmitStorageLive,
) where ) where
@ -2454,7 +2480,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
schedule_drops, schedule_drops,
), ),
}; };
if schedule_drops { if matches!(schedule_drops, ScheduleDrops::Yes) {
self.schedule_drop_for_binding(binding.var_id, binding.span, OutsideGuard); self.schedule_drop_for_binding(binding.var_id, binding.span, OutsideGuard);
} }
let rvalue = match binding.binding_mode.0 { let rvalue = match binding.binding_mode.0 {