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make retagging work even with 'unstable' places

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This commit is contained in:
Ralf Jung 2022-12-05 15:17:11 +01:00
parent c5351ad4dc
commit 9397ea1368
15 changed files with 135 additions and 128 deletions
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16
compiler/rustc_const_eval/src/interpret/machine.rs
View file

@ -373,9 +373,21 @@ pub trait Machine<'mir, 'tcx>: Sized {
Ok(())
}
/// Executes a retagging operation.
/// Executes a retagging operation for a single pointer.
/// Returns the possibly adjusted pointer.
#[inline]
fn retag(
fn retag_ptr_value(
_ecx: &mut InterpCx<'mir, 'tcx, Self>,
_kind: mir::RetagKind,
val: &ImmTy<'tcx, Self::Provenance>,
) -> InterpResult<'tcx, ImmTy<'tcx, Self::Provenance>> {
Ok(val.clone())
}
/// Executes a retagging operation on a compound value.
/// Replaces all pointers stored in the given place.
#[inline]
fn retag_place_contents(
_ecx: &mut InterpCx<'mir, 'tcx, Self>,
_kind: mir::RetagKind,
_place: &PlaceTy<'tcx, Self::Provenance>,

39
compiler/rustc_const_eval/src/interpret/step.rs
View file

@ -8,7 +8,7 @@ use rustc_middle::mir;
use rustc_middle::mir::interpret::{InterpResult, Scalar};
use rustc_middle::ty::layout::LayoutOf;
use super::{InterpCx, Machine};
use super::{ImmTy, InterpCx, Machine};
/// Classify whether an operator is "left-homogeneous", i.e., the LHS has the
/// same type as the result.
@ -108,7 +108,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
// Stacked Borrows.
Retag(kind, place) => {
let dest = self.eval_place(**place)?;
M::retag(self, *kind, &dest)?;
M::retag_place_contents(self, *kind, &dest)?;
}
Intrinsic(box ref intrinsic) => self.emulate_nondiverging_intrinsic(intrinsic)?,
@ -247,10 +247,41 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
self.write_scalar(Scalar::from_machine_usize(len, self), &dest)?;
}
AddressOf(_, place) | Ref(_, _, place) => {
Ref(_, borrow_kind, place) => {
let src = self.eval_place(place)?;
let place = self.force_allocation(&src)?;
self.write_immediate(place.to_ref(self), &dest)?;
let val = ImmTy::from_immediate(place.to_ref(self), dest.layout);
// A fresh reference was created, make sure it gets retagged.
let val = M::retag_ptr_value(
self,
if borrow_kind.allows_two_phase_borrow() {
mir::RetagKind::TwoPhase
} else {
mir::RetagKind::Default
},
&val,
)?;
self.write_immediate(*val, &dest)?;
}
AddressOf(_, place) => {
// Figure out whether this is an addr_of of an already raw place.
let place_base_raw = if place.has_deref() {
let ty = self.frame().body.local_decls[place.local].ty;
ty.is_unsafe_ptr()
} else {
// Not a deref, and thus not raw.
false
};
let src = self.eval_place(place)?;
let place = self.force_allocation(&src)?;
let mut val = ImmTy::from_immediate(place.to_ref(self), dest.layout);
if !place_base_raw {
// If this was not already raw, it needs retagging.
val = M::retag_ptr_value(self, mir::RetagKind::Raw, &val)?;
}
self.write_immediate(*val, &dest)?;
}
NullaryOp(null_op, ty) => {

2
compiler/rustc_middle/src/mir/syntax.rs
View file

@ -400,7 +400,7 @@ impl std::fmt::Display for NonDivergingIntrinsic<'_> {
#[derive(Copy, Clone, TyEncodable, TyDecodable, Debug, PartialEq, Eq, Hash, HashStable)]
#[rustc_pass_by_value]
pub enum RetagKind {
/// The initial retag when entering a function.
/// The initial retag of arguments when entering a function.
FnEntry,
/// Retag preparing for a two-phase borrow.
TwoPhase,

53
compiler/rustc_mir_transform/src/add_retag.rs
View file

@ -10,16 +10,6 @@ use rustc_middle::ty::{self, Ty, TyCtxt};
pub struct AddRetag;
/// Determines whether this place is "stable": Whether, if we evaluate it again
/// after the assignment, we can be sure to obtain the same place value.
/// (Concurrent accesses by other threads are no problem as these are anyway non-atomic
/// copies. Data races are UB.)
fn is_stable(place: PlaceRef<'_>) -> bool {
// Which place this evaluates to can change with any memory write,
// so cannot assume deref to be stable.
!place.has_deref()
}
/// Determine whether this type may contain a reference (or box), and thus needs retagging.
/// We will only recurse `depth` times into Tuples/ADTs to bound the cost of this.
fn may_contain_reference<'tcx>(ty: Ty<'tcx>, depth: u32, tcx: TyCtxt<'tcx>) -> bool {
@ -69,22 +59,10 @@ impl<'tcx> MirPass<'tcx> for AddRetag {
let basic_blocks = body.basic_blocks.as_mut();
let local_decls = &body.local_decls;
let needs_retag = |place: &Place<'tcx>| {
// FIXME: Instead of giving up for unstable places, we should introduce
// a temporary and retag on that.
is_stable(place.as_ref())
!place.has_deref() // we're not eally interested in stores to "outside" locations, they are hard to keep track of anyway
&& may_contain_reference(place.ty(&*local_decls, tcx).ty, /*depth*/ 3, tcx)
&& !local_decls[place.local].is_deref_temp()
};
let place_base_raw = |place: &Place<'tcx>| {
// If this is a `Deref`, get the type of what we are deref'ing.
if place.has_deref() {
let ty = &local_decls[place.local].ty;
ty.is_unsafe_ptr()
} else {
// Not a deref, and thus not raw.
false
}
};
// PART 1
// Retag arguments at the beginning of the start block.
@ -108,7 +86,7 @@ impl<'tcx> MirPass<'tcx> for AddRetag {
}
// PART 2
// Retag return values of functions. Also escape-to-raw the argument of `drop`.
// Retag return values of functions.
// We collect the return destinations because we cannot mutate while iterating.
let returns = basic_blocks
.iter_mut()
@ -140,30 +118,25 @@ impl<'tcx> MirPass<'tcx> for AddRetag {
}
// PART 3
// Add retag after assignment.
// Add retag after assignments where data "enters" this function: the RHS is behind a deref and the LHS is not.
for block_data in basic_blocks {
// We want to insert statements as we iterate. To this end, we
// iterate backwards using indices.
for i in (0..block_data.statements.len()).rev() {
let (retag_kind, place) = match block_data.statements[i].kind {
// Retag-as-raw after escaping to a raw pointer, if the referent
// is not already a raw pointer.
StatementKind::Assign(box (lplace, Rvalue::AddressOf(_, ref rplace)))
if !place_base_raw(rplace) =>
{
(RetagKind::Raw, lplace)
}
// Retag after assignments of reference type.
StatementKind::Assign(box (ref place, ref rvalue)) if needs_retag(place) => {
let kind = match rvalue {
Rvalue::Ref(_, borrow_kind, _)
if borrow_kind.allows_two_phase_borrow() =>
{
RetagKind::TwoPhase
}
_ => RetagKind::Default,
let add_retag = match rvalue {
// Ptr-creating operations already do their own internal retagging, no
// need to also add a retag statement.
Rvalue::Ref(..) | Rvalue::AddressOf(..) => false,
_ => true,
};
(kind, *place)
if add_retag {
(RetagKind::Default, *place)
} else {
continue;
}
}
// Do nothing for the rest
_ => continue,

10
compiler/rustc_mir_transform/src/generator.rs
View file

@ -985,16 +985,6 @@ fn create_generator_drop_shim<'tcx>(
tcx.mk_ptr(ty::TypeAndMut { ty: gen_ty, mutbl: hir::Mutability::Mut }),
source_info,
);
if tcx.sess.opts.unstable_opts.mir_emit_retag {
// Alias tracking must know we changed the type
body.basic_blocks_mut()[START_BLOCK].statements.insert(
0,
Statement {
source_info,
kind: StatementKind::Retag(RetagKind::Raw, Box::new(Place::from(SELF_ARG))),
},
)
}
// Make sure we remove dead blocks to remove
// unrelated code from the resume part of the function

10
compiler/rustc_mir_transform/src/shim.rs
View file

@ -177,16 +177,6 @@ fn build_drop_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>>)
if ty.is_some() {
// The first argument (index 0), but add 1 for the return value.
let dropee_ptr = Place::from(Local::new(1 + 0));
if tcx.sess.opts.unstable_opts.mir_emit_retag {
// Function arguments should be retagged, and we make this one raw.
body.basic_blocks_mut()[START_BLOCK].statements.insert(
0,
Statement {
source_info,
kind: StatementKind::Retag(RetagKind::Raw, Box::new(dropee_ptr)),
},
);
}
let patch = {
let param_env = tcx.param_env_reveal_all_normalized(def_id);
let mut elaborator =

4
src/test/mir-opt/inline/inline_retag.bar.Inline.after.mir
View file

@ -38,9 +38,7 @@ fn bar() -> bool {
// + literal: Const { ty: &i32, val: Unevaluated(bar, [], Some(promoted[1])) }
Retag(_10); // scope 1 at $DIR/inline_retag.rs:+2:7: +2:9
_4 = &(*_10); // scope 1 at $DIR/inline_retag.rs:+2:7: +2:9
Retag(_4); // scope 1 at $DIR/inline_retag.rs:+2:7: +2:9
_3 = &(*_4); // scope 1 at $DIR/inline_retag.rs:+2:7: +2:9
Retag(_3); // scope 1 at $DIR/inline_retag.rs:+2:7: +2:9
StorageLive(_6); // scope 1 at $DIR/inline_retag.rs:+2:11: +2:14
StorageLive(_7); // scope 1 at $DIR/inline_retag.rs:+2:11: +2:14
_9 = const _; // scope 1 at $DIR/inline_retag.rs:+2:11: +2:14
@ -49,9 +47,7 @@ fn bar() -> bool {
// + literal: Const { ty: &i32, val: Unevaluated(bar, [], Some(promoted[0])) }
Retag(_9); // scope 1 at $DIR/inline_retag.rs:+2:11: +2:14
_7 = &(*_9); // scope 1 at $DIR/inline_retag.rs:+2:11: +2:14
Retag(_7); // scope 1 at $DIR/inline_retag.rs:+2:11: +2:14
_6 = &(*_7); // scope 1 at $DIR/inline_retag.rs:+2:11: +2:14
Retag(_6); // scope 1 at $DIR/inline_retag.rs:+2:11: +2:14
Retag(_3); // scope 2 at $DIR/inline_retag.rs:16:8: 16:9
Retag(_6); // scope 2 at $DIR/inline_retag.rs:16:17: 16:18
StorageLive(_11); // scope 2 at $DIR/inline_retag.rs:17:5: 17:7

10
src/test/mir-opt/retag.array_casts.SimplifyCfg-elaborate-drops.after.mir
View file

@ -68,9 +68,7 @@ fn array_casts() -> () {
StorageLive(_3); // scope 1 at $DIR/retag.rs:+2:13: +2:19
StorageLive(_4); // scope 1 at $DIR/retag.rs:+2:13: +2:19
_4 = &mut _1; // scope 1 at $DIR/retag.rs:+2:13: +2:19
Retag(_4); // scope 1 at $DIR/retag.rs:+2:13: +2:19
_3 = &raw mut (*_4); // scope 1 at $DIR/retag.rs:+2:13: +2:19
Retag([raw] _3); // scope 1 at $DIR/retag.rs:+2:13: +2:19
_2 = move _3 as *mut usize (Pointer(ArrayToPointer)); // scope 1 at $DIR/retag.rs:+2:13: +2:33
StorageDead(_3); // scope 1 at $DIR/retag.rs:+2:32: +2:33
StorageDead(_4); // scope 1 at $DIR/retag.rs:+2:33: +2:34
@ -96,9 +94,7 @@ fn array_casts() -> () {
StorageLive(_10); // scope 4 at $DIR/retag.rs:+6:13: +6:15
StorageLive(_11); // scope 4 at $DIR/retag.rs:+6:13: +6:15
_11 = &_8; // scope 4 at $DIR/retag.rs:+6:13: +6:15
Retag(_11); // scope 4 at $DIR/retag.rs:+6:13: +6:15
_10 = &raw const (*_11); // scope 4 at $DIR/retag.rs:+6:13: +6:15
Retag([raw] _10); // scope 4 at $DIR/retag.rs:+6:13: +6:15
_9 = move _10 as *const usize (Pointer(ArrayToPointer)); // scope 4 at $DIR/retag.rs:+6:13: +6:31
StorageDead(_10); // scope 4 at $DIR/retag.rs:+6:30: +6:31
StorageDead(_11); // scope 4 at $DIR/retag.rs:+6:31: +6:32
@ -119,7 +115,6 @@ fn array_casts() -> () {
StorageDead(_17); // scope 6 at $DIR/retag.rs:+7:33: +7:34
_15 = (*_16); // scope 6 at $DIR/retag.rs:+7:25: +7:34
_14 = &_15; // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
Retag(_14); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
StorageLive(_18); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
_35 = const _; // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
// mir::Constant
@ -127,7 +122,6 @@ fn array_casts() -> () {
// + literal: Const { ty: &usize, val: Unevaluated(array_casts, [], Some(promoted[0])) }
Retag(_35); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
_18 = &(*_35); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
Retag(_18); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
Deinit(_13); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
(_13.0: &usize) = move _14; // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
(_13.1: &usize) = move _18; // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
@ -164,15 +158,11 @@ fn array_casts() -> () {
StorageLive(_30); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
StorageLive(_31); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
_31 = &(*_20); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
Retag(_31); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
_30 = &(*_31); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
Retag(_30); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
StorageLive(_32); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
StorageLive(_33); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
_33 = &(*_21); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
Retag(_33); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
_32 = &(*_33); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
Retag(_32); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
StorageLive(_34); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
Deinit(_34); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
discriminant(_34) = 0; // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL

1
src/test/mir-opt/retag.core.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir
View file

@ -6,7 +6,6 @@ fn std::ptr::drop_in_place(_1: *mut Test) -> () {
let mut _3: (); // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
bb0: {
Retag([raw] _1); // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
_2 = &mut (*_1); // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
_3 = <Test as Drop>::drop(move _2) -> bb1; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
// mir::Constant

1
src/test/mir-opt/retag.main-{closure#0}.SimplifyCfg-elaborate-drops.after.mir
View file

@ -15,7 +15,6 @@ fn main::{closure#0}(_1: &[closure@main::{closure#0}], _2: &i32) -> &i32 {
_3 = _2; // scope 0 at $DIR/retag.rs:+1:18: +1:19
Retag(_3); // scope 0 at $DIR/retag.rs:+1:18: +1:19
_0 = &(*_2); // scope 1 at $DIR/retag.rs:+2:9: +2:10
Retag(_0); // scope 1 at $DIR/retag.rs:+2:9: +2:10
StorageDead(_3); // scope 0 at $DIR/retag.rs:+3:5: +3:6
return; // scope 0 at $DIR/retag.rs:+3:6: +3:6
}

11
src/test/mir-opt/retag.main.SimplifyCfg-elaborate-drops.after.mir
View file

@ -65,13 +65,10 @@ fn main() -> () {
Deinit(_5); // scope 1 at $DIR/retag.rs:+3:17: +3:24
(_5.0: i32) = const 0_i32; // scope 1 at $DIR/retag.rs:+3:17: +3:24
_4 = &_5; // scope 1 at $DIR/retag.rs:+3:17: +3:36
Retag(_4); // scope 1 at $DIR/retag.rs:+3:17: +3:36
StorageLive(_6); // scope 1 at $DIR/retag.rs:+3:29: +3:35
StorageLive(_7); // scope 1 at $DIR/retag.rs:+3:29: +3:35
_7 = &mut _1; // scope 1 at $DIR/retag.rs:+3:29: +3:35
Retag(_7); // scope 1 at $DIR/retag.rs:+3:29: +3:35
_6 = &mut (*_7); // scope 1 at $DIR/retag.rs:+3:29: +3:35
Retag([2phase] _6); // scope 1 at $DIR/retag.rs:+3:29: +3:35
_3 = Test::foo(move _4, move _6) -> [return: bb1, unwind: bb8]; // scope 1 at $DIR/retag.rs:+3:17: +3:36
// mir::Constant
// + span: $DIR/retag.rs:33:25: 33:28
@ -93,7 +90,6 @@ fn main() -> () {
_9 = move _3; // scope 2 at $DIR/retag.rs:+4:19: +4:20
Retag(_9); // scope 2 at $DIR/retag.rs:+4:19: +4:20
_8 = &mut (*_9); // scope 2 at $DIR/retag.rs:+4:19: +4:20
Retag(_8); // scope 2 at $DIR/retag.rs:+4:19: +4:20
StorageDead(_9); // scope 2 at $DIR/retag.rs:+4:22: +4:23
StorageLive(_10); // scope 3 at $DIR/retag.rs:+5:13: +5:14
_10 = move _8; // scope 3 at $DIR/retag.rs:+5:17: +5:18
@ -101,7 +97,6 @@ fn main() -> () {
StorageLive(_11); // scope 4 at $DIR/retag.rs:+7:13: +7:15
StorageLive(_12); // scope 4 at $DIR/retag.rs:+7:18: +7:29
_12 = &raw mut (*_10); // scope 4 at $DIR/retag.rs:+7:18: +7:19
Retag([raw] _12); // scope 4 at $DIR/retag.rs:+7:18: +7:19
_11 = _12; // scope 4 at $DIR/retag.rs:+7:18: +7:29
StorageDead(_12); // scope 4 at $DIR/retag.rs:+7:29: +7:30
_2 = const (); // scope 1 at $DIR/retag.rs:+2:5: +8:6
@ -122,9 +117,7 @@ fn main() -> () {
StorageLive(_17); // scope 6 at $DIR/retag.rs:+15:16: +15:18
StorageLive(_18); // scope 6 at $DIR/retag.rs:+15:16: +15:18
_18 = &_1; // scope 6 at $DIR/retag.rs:+15:16: +15:18
Retag(_18); // scope 6 at $DIR/retag.rs:+15:16: +15:18
_17 = &(*_18); // scope 6 at $DIR/retag.rs:+15:16: +15:18
Retag(_17); // scope 6 at $DIR/retag.rs:+15:16: +15:18
_15 = move _16(move _17) -> bb3; // scope 6 at $DIR/retag.rs:+15:14: +15:19
}
@ -139,7 +132,6 @@ fn main() -> () {
Deinit(_21); // scope 7 at $DIR/retag.rs:+18:5: +18:12
(_21.0: i32) = const 0_i32; // scope 7 at $DIR/retag.rs:+18:5: +18:12
_20 = &_21; // scope 7 at $DIR/retag.rs:+18:5: +18:24
Retag(_20); // scope 7 at $DIR/retag.rs:+18:5: +18:24
StorageLive(_22); // scope 7 at $DIR/retag.rs:+18:21: +18:23
StorageLive(_23); // scope 7 at $DIR/retag.rs:+18:21: +18:23
_28 = const _; // scope 7 at $DIR/retag.rs:+18:21: +18:23
@ -148,9 +140,7 @@ fn main() -> () {
// + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
Retag(_28); // scope 7 at $DIR/retag.rs:+18:21: +18:23
_23 = &(*_28); // scope 7 at $DIR/retag.rs:+18:21: +18:23
Retag(_23); // scope 7 at $DIR/retag.rs:+18:21: +18:23
_22 = &(*_23); // scope 7 at $DIR/retag.rs:+18:21: +18:23
Retag(_22); // scope 7 at $DIR/retag.rs:+18:21: +18:23
_19 = Test::foo_shr(move _20, move _22) -> [return: bb4, unwind: bb7]; // scope 7 at $DIR/retag.rs:+18:5: +18:24
// mir::Constant
// + span: $DIR/retag.rs:48:13: 48:20
@ -171,7 +161,6 @@ fn main() -> () {
StorageLive(_25); // scope 7 at $DIR/retag.rs:+21:9: +21:11
StorageLive(_26); // scope 7 at $DIR/retag.rs:+21:14: +21:28
_26 = &raw const (*_15); // scope 7 at $DIR/retag.rs:+21:14: +21:16
Retag([raw] _26); // scope 7 at $DIR/retag.rs:+21:14: +21:16
_25 = _26; // scope 7 at $DIR/retag.rs:+21:14: +21:28
StorageDead(_26); // scope 7 at $DIR/retag.rs:+21:28: +21:29
StorageLive(_27); // scope 8 at $DIR/retag.rs:+23:5: +23:18

2
src/test/mir-opt/retag.{impl#0}-foo.SimplifyCfg-elaborate-drops.after.mir
View file

@ -11,9 +11,7 @@ fn <impl at $DIR/retag.rs:12:1: 12:10>::foo(_1: &Test, _2: &mut i32) -> &mut i32
Retag([fn entry] _2); // scope 0 at $DIR/retag.rs:+0:23: +0:24
StorageLive(_3); // scope 0 at $DIR/retag.rs:+1:9: +1:10
_3 = &mut (*_2); // scope 0 at $DIR/retag.rs:+1:9: +1:10
Retag(_3); // scope 0 at $DIR/retag.rs:+1:9: +1:10
_0 = &mut (*_3); // scope 0 at $DIR/retag.rs:+1:9: +1:10
Retag(_0); // scope 0 at $DIR/retag.rs:+1:9: +1:10
StorageDead(_3); // scope 0 at $DIR/retag.rs:+2:5: +2:6
return; // scope 0 at $DIR/retag.rs:+2:6: +2:6
}

13
src/tools/miri/src/borrow_tracker/mod.rs
View file

@ -11,7 +11,6 @@ use rustc_target::abi::Size;
use crate::*;
pub mod stacked_borrows;
use stacked_borrows::diagnostics::RetagCause;
pub type CallId = NonZeroU64;
@ -265,11 +264,19 @@ impl GlobalStateInner {
impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
fn retag(&mut self, kind: RetagKind, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
fn retag_ptr_value(&mut self, kind: RetagKind, val: &ImmTy<'tcx, Provenance>) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
let this = self.eval_context_mut();
let method = this.machine.borrow_tracker.as_ref().unwrap().borrow().borrow_tracker_method;
match method {
BorrowTrackerMethod::StackedBorrows => this.sb_retag(kind, place),
BorrowTrackerMethod::StackedBorrows => this.sb_retag_ptr_value(kind, val),
}
}
fn retag_place_contents(&mut self, kind: RetagKind, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
let this = self.eval_context_mut();
let method = this.machine.borrow_tracker.as_ref().unwrap().borrow().borrow_tracker_method;
match method {
BorrowTrackerMethod::StackedBorrows => this.sb_retag_place_contents(kind, place),
}
}

69
src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
View file

@ -1,6 +1,10 @@
//! Implements "Stacked Borrows". See <https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md>
//! for further information.
mod item;
mod stack;
pub mod diagnostics;
use log::trace;
use std::cmp;
use std::fmt::{self, Write};
@ -15,15 +19,13 @@ use rustc_target::abi::{Abi, Size};
use crate::borrow_tracker::{
stacked_borrows::diagnostics::{AllocHistory, DiagnosticCx, DiagnosticCxBuilder, TagHistory},
AccessKind, GlobalStateInner, ProtectorKind, RetagCause, RetagFields,
AccessKind, GlobalStateInner, ProtectorKind, RetagFields,
};
use crate::*;
mod item;
pub use item::{Item, Permission};
mod stack;
pub use stack::Stack;
pub mod diagnostics;
use diagnostics::RetagCause;
pub type AllocState = Stacks;
@ -807,7 +809,34 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
fn sb_retag(
fn sb_retag_ptr_value(
&mut self,
kind: RetagKind,
val: &ImmTy<'tcx, Provenance>,
) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
let this = self.eval_context_mut();
let ref_kind = match val.layout.ty.kind() {
ty::Ref(_, _, mutbl) => {
match mutbl {
Mutability::Mut =>
RefKind::Unique { two_phase: kind == RetagKind::TwoPhase },
Mutability::Not => RefKind::Shared,
}
}
ty::RawPtr(tym) => {
RefKind::Raw { mutable: tym.mutbl == Mutability::Mut }
}
_ => unreachable!(),
};
let retag_cause = match kind {
RetagKind::TwoPhase { .. } => RetagCause::TwoPhase,
RetagKind::FnEntry => unreachable!(),
RetagKind::Raw | RetagKind::Default => RetagCause::Normal,
};
this.sb_retag_reference(&val, ref_kind, retag_cause, None)
}
fn sb_retag_place_contents(
&mut self,
kind: RetagKind,
place: &PlaceTy<'tcx, Provenance>,
@ -815,9 +844,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
let this = self.eval_context_mut();
let retag_fields = this.machine.borrow_tracker.as_mut().unwrap().get_mut().retag_fields;
let retag_cause = match kind {
RetagKind::TwoPhase { .. } => RetagCause::TwoPhase,
RetagKind::Raw | RetagKind::TwoPhase { .. } => unreachable!(),
RetagKind::FnEntry => RetagCause::FnEntry,
RetagKind::Raw | RetagKind::Default => RetagCause::Normal,
RetagKind::Default => RetagCause::Normal,
};
let mut visitor = RetagVisitor { ecx: this, kind, retag_cause, retag_fields };
return visitor.visit_value(place);
@ -831,7 +860,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
}
impl<'ecx, 'mir, 'tcx> RetagVisitor<'ecx, 'mir, 'tcx> {
#[inline(always)] // yes this helps in our benchmarks
fn retag_place(
fn retag_ptr_inplace(
&mut self,
place: &PlaceTy<'tcx, Provenance>,
ref_kind: RefKind,
@ -856,7 +885,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
fn visit_box(&mut self, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
// Boxes get a weak protectors, since they may be deallocated.
self.retag_place(
self.retag_ptr_inplace(
place,
RefKind::Box,
self.retag_cause,
@ -879,10 +908,10 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
ty::Ref(_, _, mutbl) => {
let ref_kind = match mutbl {
Mutability::Mut =>
RefKind::Unique { two_phase: self.kind == RetagKind::TwoPhase },
RefKind::Unique { two_phase: false },
Mutability::Not => RefKind::Shared,
};
self.retag_place(
self.retag_ptr_inplace(
place,
ref_kind,
self.retag_cause,
@ -891,21 +920,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
.then_some(ProtectorKind::StrongProtector),
)?;
}
ty::RawPtr(tym) => {
// We definitely do *not* want to recurse into raw pointers -- wide raw
// pointers have fields, and for dyn Trait pointees those can have reference
// type!
if self.kind == RetagKind::Raw {
// Raw pointers need to be enabled.
self.retag_place(
place,
RefKind::Raw { mutable: tym.mutbl == Mutability::Mut },
self.retag_cause,
/*protector*/ None,
)?;
}
ty::RawPtr(..) => {
// We do *not* want to recurse into raw pointers -- wide raw pointers have
// fields, and for dyn Trait pointees those can have reference type!
}
_ if place.layout.ty.ty_adt_def().is_some_and(|adt| adt.is_box()) => {
ty::Adt(adt, _) if adt.is_box() => {
// Recurse for boxes, they require some tricky handling and will end up in `visit_box` above.
// (Yes this means we technically also recursively retag the allocator itself
// even if field retagging is not enabled. *shrug*)

22
src/tools/miri/src/machine.rs
View file

@ -967,8 +967,9 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
ptr: Pointer<Self::Provenance>,
) -> InterpResult<'tcx> {
match ptr.provenance {
Provenance::Concrete { alloc_id, tag } =>
intptrcast::GlobalStateInner::expose_ptr(ecx, alloc_id, tag),
Provenance::Concrete { alloc_id, tag } => {
intptrcast::GlobalStateInner::expose_ptr(ecx, alloc_id, tag)
}
Provenance::Wildcard => {
// No need to do anything for wildcard pointers as
// their provenances have already been previously exposed.
@ -1055,13 +1056,26 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
}
#[inline(always)]
fn retag(
fn retag_ptr_value(
ecx: &mut InterpCx<'mir, 'tcx, Self>,
kind: mir::RetagKind,
val: &ImmTy<'tcx, Provenance>,
) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
if ecx.machine.borrow_tracker.is_some() {
ecx.retag_ptr_value(kind, val)
} else {
Ok(val.clone())
}
}
#[inline(always)]
fn retag_place_contents(
ecx: &mut InterpCx<'mir, 'tcx, Self>,
kind: mir::RetagKind,
place: &PlaceTy<'tcx, Provenance>,
) -> InterpResult<'tcx> {
if ecx.machine.borrow_tracker.is_some() {
ecx.retag(kind, place)?;
ecx.retag_place_contents(kind, place)?;
}
Ok(())
}