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Remove Stacked Borrows GC heuristics

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This commit is contained in:
Ben Kimock 2023-11-27 16:49:16 -05:00
parent 9b8119dc21
commit 8344dae333
2 changed files with 7 additions and 13 deletions
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15
src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
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@ -37,8 +37,6 @@ pub struct Stacks {
history: AllocHistory, history: AllocHistory,
/// The set of tags that have been exposed inside this allocation. /// The set of tags that have been exposed inside this allocation.
exposed_tags: FxHashSet<BorTag>, exposed_tags: FxHashSet<BorTag>,
/// Whether this memory has been modified since the last time the tag GC ran
modified_since_last_gc: bool,
} }
/// Indicates which permissions to grant to the retagged pointer. /// Indicates which permissions to grant to the retagged pointer.
@ -450,15 +448,10 @@ impl<'tcx> Stack {
/// Integration with the BorTag garbage collector /// Integration with the BorTag garbage collector
impl Stacks { impl Stacks {
pub fn remove_unreachable_tags(&mut self, live_tags: &FxHashSet<BorTag>) { pub fn remove_unreachable_tags(&mut self, live_tags: &FxHashSet<BorTag>) {
if self.modified_since_last_gc { for (_stack_range, stack) in self.stacks.iter_mut_all() {
for (_stack_range, stack) in self.stacks.iter_mut_all() { stack.retain(live_tags);
if stack.len() > 64 {
stack.retain(live_tags);
}
}
self.history.retain(live_tags);
self.modified_since_last_gc = false;
} }
self.history.retain(live_tags);
} }
} }
@ -488,7 +481,6 @@ impl<'tcx> Stacks {
stacks: RangeMap::new(size, stack), stacks: RangeMap::new(size, stack),
history: AllocHistory::new(id, item, machine), history: AllocHistory::new(id, item, machine),
exposed_tags: FxHashSet::default(), exposed_tags: FxHashSet::default(),
modified_since_last_gc: false,
} }
} }
@ -503,7 +495,6 @@ impl<'tcx> Stacks {
&mut FxHashSet<BorTag>, &mut FxHashSet<BorTag>,
) -> InterpResult<'tcx>, ) -> InterpResult<'tcx>,
) -> InterpResult<'tcx> { ) -> InterpResult<'tcx> {
self.modified_since_last_gc = true;
for (stack_range, stack) in self.stacks.iter_mut(range.start, range.size) { for (stack_range, stack) in self.stacks.iter_mut(range.start, range.size) {
let mut dcx = dcx_builder.build(&mut self.history, Size::from_bytes(stack_range.start)); let mut dcx = dcx_builder.build(&mut self.history, Size::from_bytes(stack_range.start));
f(stack, &mut dcx, &mut self.exposed_tags)?; f(stack, &mut dcx, &mut self.exposed_tags)?;

5
src/tools/miri/tests/pass/stacked-borrows/stack-printing.rs
View File

@ -1,4 +1,7 @@
//@compile-flags: -Zmiri-permissive-provenance // We disable the GC for this test because it would change what is printed. We are testing the
// printing, not how it interacts with the GC.
//@compile-flags: -Zmiri-permissive-provenance -Zmiri-provenance-gc=0
#![feature(strict_provenance)] #![feature(strict_provenance)]
use std::{ use std::{
alloc::{self, Layout}, alloc::{self, Layout},