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Stacked Borrows: factor the logic determining the new permissions on retag into a separate function

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This commit is contained in:
Ralf Jung 2022-12-05 18:19:18 +01:00
parent 9397ea1368
commit 34c58e897f
3 changed files with 187 additions and 167 deletions
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4
src/tools/miri/src/borrow_tracker/stacked_borrows/diagnostics.rs
View file

@ -459,10 +459,10 @@ impl<'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'history, 'ecx, 'mir, 'tcx> {
Operation::Dealloc(_) => format!(" due to deallocation"), Operation::Dealloc(_) => format!(" due to deallocation"),
Operation::Access(AccessOp { kind, tag, .. }) => Operation::Access(AccessOp { kind, tag, .. }) =>
format!(" due to {kind:?} access for {tag:?}"), format!(" due to {kind:?} access for {tag:?}"),
Operation::Retag(RetagOp { orig_tag, permission, .. }) => { Operation::Retag(RetagOp { orig_tag, permission, new_tag, .. }) => {
let permission = permission let permission = permission
.expect("start_grant should set the current permission before popping a tag"); .expect("start_grant should set the current permission before popping a tag");
format!(" due to {permission:?} retag from {orig_tag:?}") format!(" due to {permission:?} retag from {orig_tag:?} (that retag created {new_tag:?})")
} }
}; };

338
src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
View file

@ -1,13 +1,13 @@
//! Implements "Stacked Borrows". See <https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md> //! Implements "Stacked Borrows". See <https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md>
//! for further information. //! for further information.
pub mod diagnostics;
mod item; mod item;
mod stack; mod stack;
pub mod diagnostics;
use log::trace; use log::trace;
use std::cmp; use std::cmp;
use std::fmt::{self, Write}; use std::fmt::Write;
use rustc_data_structures::fx::FxHashSet; use rustc_data_structures::fx::FxHashSet;
use rustc_middle::mir::{Mutability, RetagKind}; use rustc_middle::mir::{Mutability, RetagKind};
@ -23,9 +23,9 @@ use crate::borrow_tracker::{
}; };
use crate::*; use crate::*;
use diagnostics::RetagCause;
pub use item::{Item, Permission}; pub use item::{Item, Permission};
pub use stack::Stack; pub use stack::Stack;
use diagnostics::RetagCause;
pub type AllocState = Stacks; pub type AllocState = Stacks;
@ -42,30 +42,104 @@ pub struct Stacks {
modified_since_last_gc: bool, modified_since_last_gc: bool,
} }
/// Indicates which kind of reference is being created. /// Indicates which permissions to grant to the retagged pointer.
/// Used by high-level `reborrow` to compute which permissions to grant to the #[derive(Clone, Debug)]
/// new pointer. enum NewPermission {
#[derive(Copy, Clone, Hash, PartialEq, Eq)] Uniform {
enum RefKind { perm: Permission,
/// `Box`. access: Option<AccessKind>,
Box, protector: Option<ProtectorKind>,
/// `&mut`. },
Unique { two_phase: bool }, FreezeSensitive {
/// `&` with or without interior mutability. freeze_perm: Permission,
Shared, freeze_access: Option<AccessKind>,
/// `*mut`/`*const` (raw pointers). freeze_protector: Option<ProtectorKind>,
Raw { mutable: bool }, nonfreeze_perm: Permission,
nonfreeze_access: Option<AccessKind>,
// nonfreeze_protector must always be None
},
} }
impl fmt::Display for RefKind { impl NewPermission {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { /// A key function: determine the permissions to grant at a retag for the given kind of
/// reference/pointer.
fn from_ref_ty<'tcx>(
ty: ty::Ty<'tcx>,
kind: RetagKind,
cx: &crate::MiriInterpCx<'_, 'tcx>,
) -> Self {
let protector = (kind == RetagKind::FnEntry).then_some(ProtectorKind::StrongProtector);
match ty.kind() {
ty::Ref(_, pointee, Mutability::Mut) => {
if kind == RetagKind::TwoPhase {
// We mostly just give up on 2phase-borrows, and treat these exactly like raw pointers.
assert!(protector.is_none()); // RetagKind can't be both FnEntry and TwoPhase.
NewPermission::Uniform {
perm: Permission::SharedReadWrite,
access: None,
protector: None,
}
} else if pointee.is_unpin(*cx.tcx, cx.param_env()) {
// A regular full mutable reference.
NewPermission::Uniform {
perm: Permission::Unique,
access: Some(AccessKind::Write),
protector,
}
} else {
NewPermission::Uniform {
perm: Permission::SharedReadWrite,
// FIXME: We emit `dereferenceable` for `!Unpin` mutable references, so we
// should do fake accesses here. But then we run into
// <https://github.com/rust-lang/unsafe-code-guidelines/issues/381>, so for now
// we don't do that.
access: None,
protector,
}
}
}
ty::RawPtr(ty::TypeAndMut { mutbl: Mutability::Mut, .. }) => {
assert!(protector.is_none()); // RetagKind can't be both FnEntry and Raw.
// Mutable raw pointer. No access, not protected.
NewPermission::Uniform {
perm: Permission::SharedReadWrite,
access: None,
protector: None,
}
}
ty::Ref(_, _pointee, Mutability::Not) => {
NewPermission::FreezeSensitive {
freeze_perm: Permission::SharedReadOnly,
freeze_access: Some(AccessKind::Read),
freeze_protector: protector,
nonfreeze_perm: Permission::SharedReadWrite,
// Inside UnsafeCell, this does *not* count as an access, as there
// might actually be mutable references further up the stack that
// we have to keep alive.
nonfreeze_access: None,
// We do not protect inside UnsafeCell.
// This fixes https://github.com/rust-lang/rust/issues/55005.
}
}
ty::RawPtr(ty::TypeAndMut { mutbl: Mutability::Not, .. }) => {
assert!(protector.is_none()); // RetagKind can't be both FnEntry and Raw.
// `*const T`, when freshly created, are read-only in the frozen part.
NewPermission::FreezeSensitive {
freeze_perm: Permission::SharedReadOnly,
freeze_access: Some(AccessKind::Read),
freeze_protector: None,
nonfreeze_perm: Permission::SharedReadWrite,
nonfreeze_access: None,
}
}
_ => unreachable!(),
}
}
fn protector(&self) -> Option<ProtectorKind> {
match self { match self {
RefKind::Box => write!(f, "Box"), NewPermission::Uniform { protector, .. } => *protector,
RefKind::Unique { two_phase: false } => write!(f, "unique reference"), NewPermission::FreezeSensitive { freeze_protector, .. } => *freeze_protector,
RefKind::Unique { two_phase: true } => write!(f, "unique reference (two-phase)"),
RefKind::Shared => write!(f, "shared reference"),
RefKind::Raw { mutable: true } => write!(f, "raw (mutable) pointer"),
RefKind::Raw { mutable: false } => write!(f, "raw (constant) pointer"),
} }
} }
} }
@ -520,10 +594,9 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
&mut self, &mut self,
place: &MPlaceTy<'tcx, Provenance>, place: &MPlaceTy<'tcx, Provenance>,
size: Size, size: Size,
kind: RefKind, new_perm: NewPermission,
retag_cause: RetagCause, // What caused this retag, for diagnostics only
new_tag: BorTag, new_tag: BorTag,
protect: Option<ProtectorKind>, retag_cause: RetagCause, // What caused this retag, for diagnostics only
) -> InterpResult<'tcx, Option<AllocId>> { ) -> InterpResult<'tcx, Option<AllocId>> {
let this = self.eval_context_mut(); let this = self.eval_context_mut();
@ -534,20 +607,16 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
let global = this.machine.borrow_tracker.as_ref().unwrap().borrow(); let global = this.machine.borrow_tracker.as_ref().unwrap().borrow();
let ty = place.layout.ty; let ty = place.layout.ty;
if global.tracked_pointer_tags.contains(&new_tag) { if global.tracked_pointer_tags.contains(&new_tag) {
let mut kind_str = format!("{kind}"); let mut kind_str = String::new();
match kind { match new_perm {
RefKind::Unique { two_phase: false } NewPermission::Uniform { perm, .. } =>
if !ty.is_unpin(*this.tcx, this.param_env()) => write!(kind_str, "{perm:?} permission").unwrap(),
{ NewPermission::FreezeSensitive { freeze_perm, .. } if ty.is_freeze(*this.tcx, this.param_env()) =>
write!(kind_str, " (!Unpin pointee type {ty})").unwrap() write!(kind_str, "{freeze_perm:?} permission").unwrap(),
}, NewPermission::FreezeSensitive { freeze_perm, nonfreeze_perm, .. } =>
RefKind::Shared write!(kind_str, "{freeze_perm:?}/{nonfreeze_perm:?} permission for frozen/non-frozen parts").unwrap(),
if !ty.is_freeze(*this.tcx, this.param_env()) => }
{ write!(kind_str, " (pointee type {ty})").unwrap();
write!(kind_str, " (!Freeze pointee type {ty})").unwrap()
},
_ => write!(kind_str, " (pointee type {ty})").unwrap(),
};
this.emit_diagnostic(NonHaltingDiagnostic::CreatedPointerTag( this.emit_diagnostic(NonHaltingDiagnostic::CreatedPointerTag(
new_tag.inner(), new_tag.inner(),
Some(kind_str), Some(kind_str),
@ -581,7 +650,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
); );
let mut dcx = dcx.build(&mut stacked_borrows.history, base_offset); let mut dcx = dcx.build(&mut stacked_borrows.history, base_offset);
dcx.log_creation(); dcx.log_creation();
if protect.is_some() { if new_perm.protector().is_some() {
dcx.log_protector(); dcx.log_protector();
} }
}, },
@ -594,8 +663,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
if size == Size::ZERO { if size == Size::ZERO {
trace!( trace!(
"reborrow of size 0: {} reference {:?} derived from {:?} (pointee {})", "reborrow of size 0: reference {:?} derived from {:?} (pointee {})",
kind,
new_tag, new_tag,
place.ptr, place.ptr,
place.layout.ty, place.layout.ty,
@ -632,8 +700,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
} }
trace!( trace!(
"reborrow: {} reference {:?} derived from {:?} (pointee {}): {:?}, size {}", "reborrow: reference {:?} derived from {:?} (pointee {}): {:?}, size {}",
kind,
new_tag, new_tag,
orig_tag, orig_tag,
place.layout.ty, place.layout.ty,
@ -641,7 +708,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
size.bytes() size.bytes()
); );
if let Some(protect) = protect { if let Some(protect) = new_perm.protector() {
// See comment in `Stack::item_invalidated` for why we store the tag twice. // See comment in `Stack::item_invalidated` for why we store the tag twice.
this.frame_mut().extra.borrow_tracker.as_mut().unwrap().protected_tags.push(new_tag); this.frame_mut().extra.borrow_tracker.as_mut().unwrap().protected_tags.push(new_tag);
this.machine this.machine
@ -653,30 +720,45 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
.insert(new_tag, protect); .insert(new_tag, protect);
} }
// Update the stacks. // Update the stacks, according to the new permission information we are given.
// Make sure that raw pointers and mutable shared references are reborrowed "weak": match new_perm {
// There could be existing unique pointers reborrowed from them that should remain valid! NewPermission::Uniform { perm, access, protector } => {
let (perm, access) = match kind { assert!(perm != Permission::SharedReadOnly);
RefKind::Unique { two_phase } => { // Here we can avoid `borrow()` calls because we have mutable references.
// Permission is Unique only if the type is `Unpin` and this is not twophase // Note that this asserts that the allocation is mutable -- but since we are creating a
if !two_phase && place.layout.ty.is_unpin(*this.tcx, this.param_env()) { // mutable pointer, that seems reasonable.
(Permission::Unique, Some(AccessKind::Write)) let (alloc_extra, machine) = this.get_alloc_extra_mut(alloc_id)?;
} else { let stacked_borrows = alloc_extra.borrow_tracker_sb_mut().get_mut();
// FIXME: We emit `dereferenceable` for `!Unpin` mutable references, so we let item = Item::new(new_tag, perm, protector.is_some());
// should do fake accesses here. But then we run into let range = alloc_range(base_offset, size);
// <https://github.com/rust-lang/unsafe-code-guidelines/issues/381>, so for now let global = machine.borrow_tracker.as_ref().unwrap().borrow();
// we don't do that. let dcx = DiagnosticCxBuilder::retag(
(Permission::SharedReadWrite, None) machine,
retag_cause,
new_tag,
orig_tag,
alloc_range(base_offset, size),
);
stacked_borrows.for_each(range, dcx, |stack, dcx, exposed_tags| {
stack.grant(orig_tag, item, access, &global, dcx, exposed_tags)
})?;
drop(global);
if let Some(access) = access {
assert_eq!(access, AccessKind::Write);
// Make sure the data race model also knows about this.
if let Some(data_race) = alloc_extra.data_race.as_mut() {
data_race.write(alloc_id, range, machine)?;
} }
} }
RefKind::Box => (Permission::Unique, Some(AccessKind::Write)),
RefKind::Raw { mutable: true } => {
// Creating a raw ptr does not count as an access
(Permission::SharedReadWrite, None)
} }
RefKind::Shared | RefKind::Raw { mutable: false } => { NewPermission::FreezeSensitive {
// Shared references and *const are a whole different kind of game, the freeze_perm,
// permission is not uniform across the entire range! freeze_access,
freeze_protector,
nonfreeze_perm,
nonfreeze_access,
} => {
// The permission is not uniform across the entire range!
// We need a frozen-sensitive reborrow. // We need a frozen-sensitive reborrow.
// We have to use shared references to alloc/memory_extra here since // We have to use shared references to alloc/memory_extra here since
// `visit_freeze_sensitive` needs to access the global state. // `visit_freeze_sensitive` needs to access the global state.
@ -686,22 +768,12 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
// Adjust range. // Adjust range.
range.start += base_offset; range.start += base_offset;
// We are only ever `SharedReadOnly` inside the frozen bits. // We are only ever `SharedReadOnly` inside the frozen bits.
let (perm, access) = if frozen { let (perm, access, protector) = if frozen {
(Permission::SharedReadOnly, Some(AccessKind::Read)) (freeze_perm, freeze_access, freeze_protector)
} else { } else {
// Inside UnsafeCell, this does *not* count as an access, as there (nonfreeze_perm, nonfreeze_access, None)
// might actually be mutable references further up the stack that
// we have to keep alive.
(Permission::SharedReadWrite, None)
}; };
let protected = if frozen { let item = Item::new(new_tag, perm, protector.is_some());
protect.is_some()
} else {
// We do not protect inside UnsafeCell.
// This fixes https://github.com/rust-lang/rust/issues/55005.
false
};
let item = Item::new(new_tag, perm, protected);
let global = this.machine.borrow_tracker.as_ref().unwrap().borrow(); let global = this.machine.borrow_tracker.as_ref().unwrap().borrow();
let dcx = DiagnosticCxBuilder::retag( let dcx = DiagnosticCxBuilder::retag(
&this.machine, &this.machine,
@ -723,34 +795,6 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
} }
Ok(()) Ok(())
})?; })?;
return Ok(Some(alloc_id));
}
};
// Here we can avoid `borrow()` calls because we have mutable references.
// Note that this asserts that the allocation is mutable -- but since we are creating a
// mutable pointer, that seems reasonable.
let (alloc_extra, machine) = this.get_alloc_extra_mut(alloc_id)?;
let stacked_borrows = alloc_extra.borrow_tracker_sb_mut().get_mut();
let item = Item::new(new_tag, perm, protect.is_some());
let range = alloc_range(base_offset, size);
let global = machine.borrow_tracker.as_ref().unwrap().borrow();
let dcx = DiagnosticCxBuilder::retag(
machine,
retag_cause,
new_tag,
orig_tag,
alloc_range(base_offset, size),
);
stacked_borrows.for_each(range, dcx, |stack, dcx, exposed_tags| {
stack.grant(orig_tag, item, access, &global, dcx, exposed_tags)
})?;
drop(global);
if let Some(access) = access {
assert_eq!(access, AccessKind::Write);
// Make sure the data race model also knows about this.
if let Some(data_race) = alloc_extra.data_race.as_mut() {
data_race.write(alloc_id, range, machine)?;
} }
} }
@ -762,9 +806,8 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
fn sb_retag_reference( fn sb_retag_reference(
&mut self, &mut self,
val: &ImmTy<'tcx, Provenance>, val: &ImmTy<'tcx, Provenance>,
kind: RefKind, new_perm: NewPermission,
retag_cause: RetagCause, // What caused this retag, for diagnostics only cause: RetagCause, // What caused this retag, for diagnostics only
protect: Option<ProtectorKind>,
) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> { ) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
let this = self.eval_context_mut(); let this = self.eval_context_mut();
// We want a place for where the ptr *points to*, so we get one. // We want a place for where the ptr *points to*, so we get one.
@ -782,7 +825,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
let new_tag = this.machine.borrow_tracker.as_mut().unwrap().get_mut().new_ptr(); let new_tag = this.machine.borrow_tracker.as_mut().unwrap().get_mut().new_ptr();
// Reborrow. // Reborrow.
let alloc_id = this.sb_reborrow(&place, size, kind, retag_cause, new_tag, protect)?; let alloc_id = this.sb_reborrow(&place, size, new_perm, new_tag, cause)?;
// Adjust pointer. // Adjust pointer.
let new_place = place.map_provenance(|p| { let new_place = place.map_provenance(|p| {
@ -815,25 +858,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
val: &ImmTy<'tcx, Provenance>, val: &ImmTy<'tcx, Provenance>,
) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> { ) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
let this = self.eval_context_mut(); let this = self.eval_context_mut();
let ref_kind = match val.layout.ty.kind() { let new_perm = NewPermission::from_ref_ty(val.layout.ty, kind, this);
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 { let retag_cause = match kind {
RetagKind::TwoPhase { .. } => RetagCause::TwoPhase, RetagKind::TwoPhase { .. } => RetagCause::TwoPhase,
RetagKind::FnEntry => unreachable!(), RetagKind::FnEntry => unreachable!(),
RetagKind::Raw | RetagKind::Default => RetagCause::Normal, RetagKind::Raw | RetagKind::Default => RetagCause::Normal,
}; };
this.sb_retag_reference(&val, ref_kind, retag_cause, None) this.sb_retag_reference(&val, new_perm, retag_cause)
} }
fn sb_retag_place_contents( fn sb_retag_place_contents(
@ -844,7 +875,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
let this = self.eval_context_mut(); let this = self.eval_context_mut();
let retag_fields = this.machine.borrow_tracker.as_mut().unwrap().get_mut().retag_fields; let retag_fields = this.machine.borrow_tracker.as_mut().unwrap().get_mut().retag_fields;
let retag_cause = match kind { let retag_cause = match kind {
RetagKind::Raw | RetagKind::TwoPhase { .. } => unreachable!(), RetagKind::Raw | RetagKind::TwoPhase { .. } => unreachable!(), // these can only happen in `retag_ptr_value`
RetagKind::FnEntry => RetagCause::FnEntry, RetagKind::FnEntry => RetagCause::FnEntry,
RetagKind::Default => RetagCause::Normal, RetagKind::Default => RetagCause::Normal,
}; };
@ -863,12 +894,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
fn retag_ptr_inplace( fn retag_ptr_inplace(
&mut self, &mut self,
place: &PlaceTy<'tcx, Provenance>, place: &PlaceTy<'tcx, Provenance>,
ref_kind: RefKind, new_perm: NewPermission,
retag_cause: RetagCause, retag_cause: RetagCause,
protector: Option<ProtectorKind>,
) -> InterpResult<'tcx> { ) -> InterpResult<'tcx> {
let val = self.ecx.read_immediate(&self.ecx.place_to_op(place)?)?; let val = self.ecx.read_immediate(&self.ecx.place_to_op(place)?)?;
let val = self.ecx.sb_retag_reference(&val, ref_kind, retag_cause, protector)?; let val = self.ecx.sb_retag_reference(&val, new_perm, retag_cause)?;
self.ecx.write_immediate(*val, place)?; self.ecx.write_immediate(*val, place)?;
Ok(()) Ok(())
} }
@ -885,13 +915,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
fn visit_box(&mut self, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> { fn visit_box(&mut self, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
// Boxes get a weak protectors, since they may be deallocated. // Boxes get a weak protectors, since they may be deallocated.
self.retag_ptr_inplace( let new_perm = NewPermission::Uniform {
place, perm: Permission::Unique,
RefKind::Box, access: Some(AccessKind::Write),
self.retag_cause, protector: (self.kind == RetagKind::FnEntry)
/*protector*/ .then_some(ProtectorKind::WeakProtector),
(self.kind == RetagKind::FnEntry).then_some(ProtectorKind::WeakProtector), };
) self.retag_ptr_inplace(place, new_perm, self.retag_cause)
} }
fn visit_value(&mut self, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> { fn visit_value(&mut self, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
@ -905,20 +935,10 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
// Check the type of this value to see what to do with it (retag, or recurse). // Check the type of this value to see what to do with it (retag, or recurse).
match place.layout.ty.kind() { match place.layout.ty.kind() {
ty::Ref(_, _, mutbl) => { ty::Ref(..) => {
let ref_kind = match mutbl { let new_perm =
Mutability::Mut => NewPermission::from_ref_ty(place.layout.ty, self.kind, self.ecx);
RefKind::Unique { two_phase: false }, self.retag_ptr_inplace(place, new_perm, self.retag_cause)?;
Mutability::Not => RefKind::Shared,
};
self.retag_ptr_inplace(
place,
ref_kind,
self.retag_cause,
/*protector*/
(self.kind == RetagKind::FnEntry)
.then_some(ProtectorKind::StrongProtector),
)?;
} }
ty::RawPtr(..) => { ty::RawPtr(..) => {
// We do *not* want to recurse into raw pointers -- wide raw pointers have // We do *not* want to recurse into raw pointers -- wide raw pointers have
@ -972,12 +992,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
let ptr_layout = this.layout_of(this.tcx.mk_mut_ptr(return_place.layout.ty))?; let ptr_layout = this.layout_of(this.tcx.mk_mut_ptr(return_place.layout.ty))?;
let val = ImmTy::from_immediate(return_place.to_ref(this), ptr_layout); let val = ImmTy::from_immediate(return_place.to_ref(this), ptr_layout);
// Reborrow it. With protection! That is part of the point. // Reborrow it. With protection! That is part of the point.
let val = this.sb_retag_reference( let new_perm = NewPermission::Uniform {
&val, perm: Permission::Unique,
RefKind::Unique { two_phase: false }, access: Some(AccessKind::Write),
RetagCause::FnReturn, protector: Some(ProtectorKind::StrongProtector),
/*protector*/ Some(ProtectorKind::StrongProtector), };
)?; let val = this.sb_retag_reference(&val, new_perm, RetagCause::FnReturn)?;
// And use reborrowed pointer for return place. // And use reborrowed pointer for return place.
let return_place = this.ref_to_mplace(&val)?; let return_place = this.ref_to_mplace(&val)?;
this.frame_mut().return_place = return_place.into(); this.frame_mut().return_place = return_place.into();

10
src/tools/miri/src/diagnostics.rs
View file

@ -63,9 +63,9 @@ impl MachineStopType for TerminationInfo {}
/// Miri specific diagnostics /// Miri specific diagnostics
pub enum NonHaltingDiagnostic { pub enum NonHaltingDiagnostic {
/// (new_tag, new_kind, (alloc_id, base_offset, orig_tag)) /// (new_tag, new_perm, (alloc_id, base_offset, orig_tag))
/// ///
/// new_kind is `None` for base tags. /// new_perm is `None` for base tags.
CreatedPointerTag(NonZeroU64, Option<String>, Option<(AllocId, AllocRange, ProvenanceExtra)>), CreatedPointerTag(NonZeroU64, Option<String>, Option<(AllocId, AllocRange, ProvenanceExtra)>),
/// This `Item` was popped from the borrow stack. The string explains the reason. /// This `Item` was popped from the borrow stack. The string explains the reason.
PoppedPointerTag(Item, String), PoppedPointerTag(Item, String),
@ -393,10 +393,10 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
let msg = match &e { let msg = match &e {
CreatedPointerTag(tag, None, _) => format!("created base tag {tag:?}"), CreatedPointerTag(tag, None, _) => format!("created base tag {tag:?}"),
CreatedPointerTag(tag, Some(kind), None) => format!("created {tag:?} for {kind}"), CreatedPointerTag(tag, Some(perm), None) => format!("created {tag:?} with {perm} derived from unknown tag"),
CreatedPointerTag(tag, Some(kind), Some((alloc_id, range, orig_tag))) => CreatedPointerTag(tag, Some(perm), Some((alloc_id, range, orig_tag))) =>
format!( format!(
"created tag {tag:?} for {kind} at {alloc_id:?}{range:?} derived from {orig_tag:?}" "created tag {tag:?} with {perm} at {alloc_id:?}{range:?} derived from {orig_tag:?}"
), ),
PoppedPointerTag(item, cause) => format!("popped tracked tag for item {item:?}{cause}"), PoppedPointerTag(item, cause) => format!("popped tracked tag for item {item:?}{cause}"),
CreatedCallId(id) => format!("function call with id {id}"), CreatedCallId(id) => format!("function call with id {id}"),