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enable Miri to fix the bytes in an allocation (since ptr offsets have different meanings there)

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This commit is contained in:
Ralf Jung 2021-07-15 18:03:22 +02:00
parent f4b61ba509
commit adbe7554d7
3 changed files with 65 additions and 69 deletions
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40
compiler/rustc_middle/src/mir/interpret/allocation.rs
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@ -3,7 +3,7 @@
use std::borrow::Cow;
use std::convert::TryFrom;
use std::iter;
use std::ops::{Deref, DerefMut, Range};
use std::ops::{Deref, Range};
use std::ptr;
use rustc_ast::Mutability;
@ -156,16 +156,30 @@ impl<Tag> Allocation<Tag> {
impl Allocation {
/// Convert Tag and add Extra fields
pub fn with_prov_and_extra<Tag, Extra>(
pub fn convert_tag_add_extra<Tag, Extra>(
self,
mut tagger: impl FnMut(AllocId) -> Tag,
cx: &impl HasDataLayout,
extra: Extra,
mut tagger: impl FnMut(Pointer<AllocId>) -> Pointer<Tag>,
) -> Allocation<Tag, Extra> {
// Compute new pointer tags, which also adjusts the bytes.
let mut bytes = self.bytes;
let mut new_relocations = Vec::with_capacity(self.relocations.0.len());
let ptr_size = cx.data_layout().pointer_size.bytes_usize();
let endian = cx.data_layout().endian;
for &(offset, alloc_id) in self.relocations.iter() {
let idx = offset.bytes_usize();
let ptr_bytes = &mut bytes[idx..idx + ptr_size];
let bits = read_target_uint(endian, ptr_bytes).unwrap();
let (ptr_tag, ptr_offset) =
tagger(Pointer::new(alloc_id, Size::from_bytes(bits))).into_parts();
write_target_uint(endian, ptr_bytes, ptr_offset.bytes().into()).unwrap();
new_relocations.push((offset, ptr_tag));
}
// Create allocation.
Allocation {
bytes: self.bytes,
relocations: Relocations::from_presorted(
self.relocations.iter().map(|&(offset, tag)| (offset, tagger(tag))).collect(),
),
bytes,
relocations: Relocations::from_presorted(new_relocations),
init_mask: self.init_mask,
align: self.align,
mutability: self.mutability,
@ -377,7 +391,7 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
// See if we have to also write a relocation.
if let Some(provenance) = provenance {
self.relocations.insert(range.start, provenance);
self.relocations.0.insert(range.start, provenance);
}
Ok(())
@ -437,7 +451,7 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
}
// Forget all the relocations.
self.relocations.remove_range(first..last);
self.relocations.0.remove_range(first..last);
}
/// Errors if there are relocations overlapping with the edges of the
@ -597,12 +611,6 @@ impl<Tag> Deref for Relocations<Tag> {
}
}
impl<Tag> DerefMut for Relocations<Tag> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
/// A partial, owned list of relocations to transfer into another allocation.
pub struct AllocationRelocations<Tag> {
relative_relocations: Vec<(Size, Tag)>,
@ -643,7 +651,7 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
/// The affected range, as defined in the parameters to `prepare_relocation_copy` is expected
/// to be clear of relocations.
pub fn mark_relocation_range(&mut self, relocations: AllocationRelocations<Tag>) {
self.relocations.insert_presorted(relocations.relative_relocations);
self.relocations.0.insert_presorted(relocations.relative_relocations);
}
}