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more hacks to make test cases pass

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This commit is contained in:
Ralf Jung 2017-07-24 22:42:05 -07:00
parent e2d80d0423
commit 744780e794
3 changed files with 63 additions and 26 deletions
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6
src/librustc_mir/interpret/memory.rs
View file

@ -565,7 +565,7 @@ impl<'a, 'tcx> Memory<'a, 'tcx> {
Ok(())
}
/// Release a write lock prematurely. If there's just read locks, do nothing.
/// Release a write lock prematurely. If there's a read lock or someone else's lock, fail.
pub(crate) fn release_write_lock(&mut self, ptr: MemoryPointer, len: u64) -> EvalResult<'tcx> {
assert!(len > 0);
let cur_frame = self.cur_frame;
@ -580,18 +580,20 @@ impl<'a, 'tcx> Memory<'a, 'tcx> {
return Err(EvalError::InvalidMemoryLockRelease { ptr, len, frame: cur_frame, lock: lock.clone() });
}
if !range.contained_in(ptr.offset, len) {
return Err(EvalError::Unimplemented(format!("miri does not support release part of a write-locked region")));
return Err(EvalError::Unimplemented(format!("miri does not support releasing part of a write-locked region")));
}
// Release it later. We cannot do this now.
remove_list.push(*range);
}
ReadLock(_) => {
// Abort here and bubble the error outwards so that we do not even register a suspension.
return Err(EvalError::InvalidMemoryLockRelease { ptr, len, frame: cur_frame, lock: lock.clone() });
},
}
}
for range in remove_list {
trace!("Releasing {:?}", alloc.locks[&range]);
alloc.locks.remove(&range);
}

82
src/librustc_mir/interpret/validation.rs
View file

@ -9,8 +9,8 @@ use rustc::middle::region::CodeExtent;
use error::{EvalError, EvalResult};
use eval_context::{EvalContext, DynamicLifetime};
use memory::AccessKind;
use value::Value;
use memory::{AccessKind, LockInfo};
use value::{PrimVal, Value};
use lvalue::{Lvalue, LvalueExtra};
pub type ValidationQuery<'tcx> = ValidationOperand<'tcx, Lvalue<'tcx>>;
@ -36,8 +36,7 @@ impl ValidationMode {
// Validity checks
impl<'a, 'tcx> EvalContext<'a, 'tcx> {
pub(crate) fn validation_op(&mut self, op: ValidationOp, operand: &ValidationOperand<'tcx, mir::Lvalue<'tcx>>) -> EvalResult<'tcx> {
// Determine if this method is whitelisted and hence we do not perform any validation.
// TODO: Do not do this.
// HACK: Determine if this method is whitelisted and hence we do not perform any validation.
{
// The regexp we use for filtering
use regex::Regex;
@ -46,6 +45,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
std::mem::swap::|\
std::mem::uninitialized::|\
std::ptr::read::|\
std::panicking::try::do_call::|\
<std::vec::Vec<T>><[a-zA-Z0-9_]+>::into_boxed_slice$\
)").unwrap();
}
@ -64,18 +64,30 @@ std::ptr::read::|\
let mode = match op {
ValidationOp::Acquire => ValidationMode::Acquire,
ValidationOp::Release => ValidationMode::Release,
ValidationOp::Suspend(ce) => {
if operand.mutbl == MutImmutable {
// Nothing to do when suspending immutable things
return Ok(());
}
let lft = DynamicLifetime { frame: self.cur_frame(), region: Some(ce) };
trace!("Suspending {:?} until {:?}", query, ce);
self.suspended.entry(lft).or_insert_with(Vec::new).push(query.clone());
ValidationMode::Release
}
ValidationOp::Suspend(_) => ValidationMode::Release,
};
match self.validate(query.clone(), mode) {
Err(EvalError::InvalidMemoryLockRelease { lock: LockInfo::ReadLock(_), .. }) => {
// HACK: When &x is used while x is already borrowed read-only, AddValidation still
// emits suspension. This code is legit, so just ignore the error *and*
// do NOT register a suspension.
// TODO: Integrate AddValidation better with borrowck so that we can/ not emit
// these wrong validation statements. This is all pretty fragile right now.
return Ok(());
}
res => res,
}?;
// Now that we are here, we know things went well. Time to register the suspension.
match op {
ValidationOp::Suspend(ce) => {
if query.mutbl == MutMutable {
let lft = DynamicLifetime { frame: self.cur_frame(), region: Some(ce) };
trace!("Suspending {:?} until {:?}", query, ce);
self.suspended.entry(lft).or_insert_with(Vec::new).push(query);
}
}
_ => {}
};
self.validate(query, mode)?;
Ok(())
}
@ -85,6 +97,7 @@ std::ptr::read::|\
let lft = DynamicLifetime { frame: self.cur_frame(), region: Some(ce) };
if let Some(queries) = self.suspended.remove(&lft) {
for query in queries {
trace!("Recovering {:?} from suspension", query);
self.validate(query, ValidationMode::Recover(ce))?;
}
}
@ -111,7 +124,18 @@ std::ptr::read::|\
// Check alignment and non-NULLness
let (_, align) = self.size_and_align_of_dst(pointee_ty, val)?;
let ptr = val.into_ptr(&mut self.memory)?;
self.memory.check_align(ptr, align)?;
match self.memory.check_align(ptr, align) {
// HACK: If, during releasing, we hit memory we cannot use, we just ignore that.
// This can happen because releases are added before drop elaboration.
// TODO: Fix the MIR so that these releases do not happen.
res @ Err(EvalError::DanglingPointerDeref) | res @ Err(EvalError::ReadUndefBytes) => {
if let ValidationMode::Release = mode {
return Ok(());
}
res
}
res => res,
}?;
// Recurse
let pointee_lvalue = self.val_to_lvalue(val, pointee_ty)?;
@ -136,14 +160,24 @@ std::ptr::read::|\
}
}
// For now, bail out if we hit a dead local.
// TODO: Reconsider this. I think MIR should rather be fixed.
// HACK: For now, bail out if we hit a dead local during recovery (can happen because sometimes we have
// StorageDead before EndRegion).
// TODO: We should rather fix the MIR.
// HACK: Releasing on dead/undef local variables is a NOP. This can happen because of releases being added
// before drop elaboration.
// TODO: Fix the MIR so that these releases do not happen.
match query.lval {
Lvalue::Local { frame, local } => {
if let Err(EvalError::DeadLocal) = self.stack[frame].get_local(local) {
return Ok(())
let res = self.stack[frame].get_local(local);
match (res, mode) {
(Err(EvalError::DeadLocal), ValidationMode::Recover(_)) |
(Err(EvalError::DeadLocal), ValidationMode::Release) |
(Ok(Value::ByVal(PrimVal::Undef)), ValidationMode::Release) => {
return Ok(());
}
_ => {},
}
}
},
_ => {}
}
@ -229,7 +263,7 @@ std::ptr::read::|\
if query.re == None {
match *region {
ReScope(ce) => query.re = Some(ce),
// It is possible for us to encode erased lifetimes here because the lifetimes in
// It is possible for us to encounter erased lifetimes here because the lifetimes in
// this functions' Subst will be erased.
_ => {},
}
@ -279,10 +313,10 @@ std::ptr::read::|\
};
self.read_size_and_align_from_vtable(vtable)?;
// TODO: Check that the vtable contains all the function pointers we expect it to have.
// TODO: Is there anything we can/should validate here? Trait objects cannot have any operations performed
// Trait objects cannot have any operations performed
// on them directly. We cannot, in general, even acquire any locks as the trait object *could*
// contain an UnsafeCell. If we call functions to get access to data, we will validate
// their return values. So, it doesn't seem like there's anything to do.
// their return values. So, it doesn't seem like there's anything else to do.
Ok(())
}
TyAdt(adt, subst) => {

1
tests/run-pass/cast-rfc0401-vtable-kinds.rs
View file

@ -55,4 +55,5 @@ fn main() {
let bar_ref : *const BarS<[u32]> = foo_to_bar(u);
let z : &BarS<[u32]> = unsafe{&*bar_ref};
assert_eq!(&z.0, &[0,1,2]);
// If validation fails here, that's likely because an immutable suspension is recovered mutably.
}