bjoernager/rust
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interpret: better control over whether we read data with provenance, and implicit provenance stripping where possible

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This commit is contained in:
Ralf Jung 2022-06-02 20:30:29 -04:00
parent 5e6bb83268
commit 47d11a8483
22 changed files with 502 additions and 411 deletions
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22
compiler/rustc_const_eval/src/interpret/operand.rs
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@ -15,8 +15,8 @@ use rustc_target::abi::{VariantIdx, Variants};
use super::{
alloc_range, from_known_layout, mir_assign_valid_types, AllocId, ConstValue, GlobalId,
InterpCx, InterpResult, MPlaceTy, Machine, MemPlace, Place, PlaceTy, Pointer, Provenance,
Scalar, ScalarMaybeUninit,
InterpCx, InterpResult, MPlaceTy, Machine, MemPlace, Place, PlaceTy, Pointer,
PointerArithmetic, Provenance, Scalar, ScalarMaybeUninit,
};
/// An `Immediate` represents a single immediate self-contained Rust value.
@ -284,11 +284,15 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
Abi::Scalar(s) if force => Some(s.primitive()),
_ => None,
};
if let Some(_s) = scalar_layout {
let number_may_have_provenance = !M::enforce_number_no_provenance(self);
if let Some(s) = scalar_layout {
//FIXME(#96185): let size = s.size(self);
//FIXME(#96185): assert_eq!(size, mplace.layout.size, "abi::Scalar size does not match layout size");
let size = mplace.layout.size; //FIXME(#96185): remove this line
let scalar = alloc.read_scalar(alloc_range(Size::ZERO, size))?;
let scalar = alloc.read_scalar(
alloc_range(Size::ZERO, size),
s.is_ptr() || (number_may_have_provenance && size == self.pointer_size()),
)?;
return Ok(Some(ImmTy { imm: scalar.into(), layout: mplace.layout }));
}
let scalar_pair_layout = match mplace.layout.abi {
@ -306,8 +310,14 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
let (a_size, b_size) = (a.size(self), b.size(self));
let b_offset = a_size.align_to(b.align(self).abi);
assert!(b_offset.bytes() > 0); // in `operand_field` we use the offset to tell apart the fields
let a_val = alloc.read_scalar(alloc_range(Size::ZERO, a_size))?;
let b_val = alloc.read_scalar(alloc_range(b_offset, b_size))?;
let a_val = alloc.read_scalar(
alloc_range(Size::ZERO, a_size),
a.is_ptr() || (number_may_have_provenance && a_size == self.pointer_size()),
)?;
let b_val = alloc.read_scalar(
alloc_range(b_offset, b_size),
b.is_ptr() || (number_may_have_provenance && b_size == self.pointer_size()),
)?;
return Ok(Some(ImmTy {
imm: Immediate::ScalarPair(a_val, b_val),
layout: mplace.layout,