diff options
| -rw-r--r-- | compiler/rustc_borrowck/src/lib.rs | 56 |
1 files changed, 24 insertions, 32 deletions
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs index 820952283bd..1bc69abe6f9 100644 --- a/compiler/rustc_borrowck/src/lib.rs +++ b/compiler/rustc_borrowck/src/lib.rs @@ -22,6 +22,7 @@ use std::cell::RefCell; use std::marker::PhantomData; use std::ops::{ControlFlow, Deref}; +use borrow_set::LocalsStateAtExit; use root_cx::BorrowCheckRootCtxt; use rustc_abi::FieldIdx; use rustc_data_structures::fx::{FxIndexMap, FxIndexSet}; @@ -382,7 +383,6 @@ fn do_mir_borrowck<'tcx>( location_table: &location_table, movable_coroutine, fn_self_span_reported: Default::default(), - locals_are_invalidated_at_exit, access_place_error_reported: Default::default(), reservation_error_reported: Default::default(), uninitialized_error_reported: Default::default(), @@ -441,7 +441,6 @@ fn do_mir_borrowck<'tcx>( move_data: &move_data, location_table: &location_table, movable_coroutine, - locals_are_invalidated_at_exit, fn_self_span_reported: Default::default(), access_place_error_reported: Default::default(), reservation_error_reported: Default::default(), @@ -643,13 +642,6 @@ struct MirBorrowckCtxt<'a, 'infcx, 'tcx> { location_table: &'a PoloniusLocationTable, movable_coroutine: bool, - /// This keeps track of whether local variables are free-ed when the function - /// exits even without a `StorageDead`, which appears to be the case for - /// constants. - /// - /// I'm not sure this is the right approach - @eddyb could you try and - /// figure this out? - locals_are_invalidated_at_exit: bool, /// This field keeps track of when borrow errors are reported in the access_place function /// so that there is no duplicate reporting. This field cannot also be used for the conflicting /// borrow errors that is handled by the `reservation_error_reported` field as the inclusion @@ -925,13 +917,20 @@ impl<'a, 'tcx> ResultsVisitor<'a, 'tcx, Borrowck<'a, 'tcx>> for MirBorrowckCtxt< | TerminatorKind::Return | TerminatorKind::TailCall { .. } | TerminatorKind::CoroutineDrop => { - // Returning from the function implicitly kills storage for all locals and statics. - // Often, the storage will already have been killed by an explicit - // StorageDead, but we don't always emit those (notably on unwind paths), - // so this "extra check" serves as a kind of backup. - for i in state.borrows.iter() { - let borrow = &self.borrow_set[i]; - self.check_for_invalidation_at_exit(loc, borrow, span); + match self.borrow_set.locals_state_at_exit() { + LocalsStateAtExit::AllAreInvalidated => { + // Returning from the function implicitly kills storage for all locals and statics. + // Often, the storage will already have been killed by an explicit + // StorageDead, but we don't always emit those (notably on unwind paths), + // so this "extra check" serves as a kind of backup. + for i in state.borrows.iter() { + let borrow = &self.borrow_set[i]; + self.check_for_invalidation_at_exit(loc, borrow, span); + } + } + // If we do not implicitly invalidate all locals on exit, + // we check for conflicts when dropping or moving this local. + LocalsStateAtExit::SomeAreInvalidated { has_storage_dead_or_moved: _ } => {} } } @@ -1703,22 +1702,15 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, '_, 'tcx> { // we'll have a memory leak) and assume that all statics have a destructor. // // FIXME: allow thread-locals to borrow other thread locals? - - let (might_be_alive, will_be_dropped) = - if self.body.local_decls[root_place.local].is_ref_to_thread_local() { - // Thread-locals might be dropped after the function exits - // We have to dereference the outer reference because - // borrows don't conflict behind shared references. - root_place.projection = TyCtxtConsts::DEREF_PROJECTION; - (true, true) - } else { - (false, self.locals_are_invalidated_at_exit) - }; - - if !will_be_dropped { - debug!("place_is_invalidated_at_exit({:?}) - won't be dropped", place); - return; - } + let might_be_alive = if self.body.local_decls[root_place.local].is_ref_to_thread_local() { + // Thread-locals might be dropped after the function exits + // We have to dereference the outer reference because + // borrows don't conflict behind shared references. + root_place.projection = TyCtxtConsts::DEREF_PROJECTION; + true + } else { + false + }; let sd = if might_be_alive { Deep } else { Shallow(None) }; |