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Validate constants during const_eval_raw

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This commit is contained in:
Oliver Scherer 2020-07-30 17:58:39 +02:00
parent ac19c3bda1
commit 083f1d7a37
4 changed files with 62 additions and 52 deletions
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51
compiler/rustc_mir/src/const_eval/eval_queries.rs
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@ -193,21 +193,7 @@ fn validate_and_turn_into_const<'tcx>(
let ecx = mk_eval_cx(tcx, tcx.def_span(key.value.instance.def_id()), key.param_env, is_static);
let val = (|| {
let mplace = ecx.raw_const_to_mplace(constant)?;
// FIXME do not validate promoteds until a decision on
// https://github.com/rust-lang/rust/issues/67465 is made
if cid.promoted.is_none() {
let mut ref_tracking = RefTracking::new(mplace);
while let Some((mplace, path)) = ref_tracking.todo.pop() {
ecx.const_validate_operand(
mplace.into(),
path,
&mut ref_tracking,
/*may_ref_to_static*/ ecx.memory.extra.can_access_statics,
)?;
}
}
// Now that we validated, turn this into a proper constant.
// Turn this into a proper constant.
// Statics/promoteds are always `ByRef`, for the rest `op_to_const` decides
// whether they become immediates.
if is_static || cid.promoted.is_some() {
@ -221,6 +207,7 @@ fn validate_and_turn_into_const<'tcx>(
}
})();
// FIXME: Can this ever be an error and not be a compiler bug or can we just ICE here?
val.map_err(|error| {
let err = ConstEvalErr::new(&ecx, error, None);
err.struct_error(ecx.tcx, "it is undefined behavior to use this value", |mut diag| {
@ -319,7 +306,6 @@ pub fn const_eval_raw_provider<'tcx>(
let res = ecx.load_mir(cid.instance.def, cid.promoted);
res.and_then(|body| eval_body_using_ecx(&mut ecx, cid, &body))
.map(|place| RawConst { alloc_id: place.ptr.assert_ptr().alloc_id, ty: place.layout.ty })
.map_err(|error| {
let err = ConstEvalErr::new(&ecx, error, None);
// errors in statics are always emitted as fatal errors
@ -397,4 +383,37 @@ pub fn const_eval_raw_provider<'tcx>(
err.report_as_error(ecx.tcx.at(ecx.cur_span()), "could not evaluate constant")
}
})
.and_then(|mplace| {
// Since evaluation had no errors, valiate the resulting constant:
let validation = try {
// FIXME do not validate promoteds until a decision on
// https://github.com/rust-lang/rust/issues/67465 is made
if cid.promoted.is_none() {
let mut ref_tracking = RefTracking::new(mplace);
while let Some((mplace, path)) = ref_tracking.todo.pop() {
ecx.const_validate_operand(
mplace.into(),
path,
&mut ref_tracking,
/*may_ref_to_static*/ ecx.memory.extra.can_access_statics,
)?;
}
}
};
if let Err(error) = validation {
// Validation failed, report an error
let err = ConstEvalErr::new(&ecx, error, None);
Err(err.struct_error(
ecx.tcx,
"it is undefined behavior to use this value",
|mut diag| {
diag.note(note_on_undefined_behavior_error());
diag.emit();
},
))
} else {
// Convert to raw constant
Ok(RawConst { alloc_id: mplace.ptr.assert_ptr().alloc_id, ty: mplace.layout.ty })
}
})
}