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Auto merge of #85376 - RalfJung:ptrless-allocs, r=oli-obk

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CTFE core engine allocation & memory API improvemenets

This is a first step towards https://github.com/rust-lang/miri/issues/841.
- make `Allocation` API offset-based (no more making up `Pointer`s just to access an `Allocation`)
- make `Memory` API higher-level (combine checking for access and getting access into one operation)

The Miri-side PR is at https://github.com/rust-lang/miri/pull/1804.
r? `@oli-obk`
This commit is contained in:
bors 2021-05-19 10:11:28 +00:00
commit 3e827cc21e
19 changed files with 599 additions and 512 deletions
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355
compiler/rustc_middle/src/mir/interpret/allocation.rs
View file

@ -4,16 +4,22 @@ use std::borrow::Cow;
use std::convert::TryFrom;
use std::iter;
use std::ops::{Deref, DerefMut, Range};
use std::ptr;
use rustc_ast::Mutability;
use rustc_data_structures::sorted_map::SortedMap;
use rustc_target::abi::{Align, HasDataLayout, Size};
use super::{
read_target_uint, write_target_uint, AllocId, InterpResult, Pointer, Scalar, ScalarMaybeUninit,
UninitBytesAccess,
read_target_uint, write_target_uint, AllocId, InterpError, Pointer, Scalar, ScalarMaybeUninit,
UndefinedBehaviorInfo, UninitBytesAccess, UnsupportedOpInfo,
};
/// This type represents an Allocation in the Miri/CTFE core engine.
///
/// Its public API is rather low-level, working directly with allocation offsets and a custom error
/// type to account for the lack of an AllocId on this level. The Miri/CTFE core engine `memory`
/// module provides higher-level access.
#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
#[derive(HashStable)]
pub struct Allocation<Tag = (), Extra = ()> {
@ -38,49 +44,58 @@ pub struct Allocation<Tag = (), Extra = ()> {
pub extra: Extra,
}
pub trait AllocationExtra<Tag>: std::fmt::Debug + Clone {
// There is no constructor in here because the constructor's type depends
// on `MemoryKind`, and making things sufficiently generic leads to painful
// inference failure.
/// We have our own error type that does not know about the `AllocId`; that information
/// is added when converting to `InterpError`.
#[derive(Debug)]
pub enum AllocError {
/// Encountered a pointer where we needed raw bytes.
ReadPointerAsBytes,
/// Using uninitialized data where it is not allowed.
InvalidUninitBytes(Option<UninitBytesAccess>),
}
pub type AllocResult<T = ()> = Result<T, AllocError>;
/// Hook for performing extra checks on a memory read access.
///
/// Takes read-only access to the allocation so we can keep all the memory read
/// operations take `&self`. Use a `RefCell` in `AllocExtra` if you
/// need to mutate.
#[inline(always)]
fn memory_read(
_alloc: &Allocation<Tag, Self>,
_ptr: Pointer<Tag>,
_size: Size,
) -> InterpResult<'tcx> {
Ok(())
}
/// Hook for performing extra checks on a memory write access.
#[inline(always)]
fn memory_written(
_alloc: &mut Allocation<Tag, Self>,
_ptr: Pointer<Tag>,
_size: Size,
) -> InterpResult<'tcx> {
Ok(())
}
/// Hook for performing extra checks on a memory deallocation.
/// `size` will be the size of the allocation.
#[inline(always)]
fn memory_deallocated(
_alloc: &mut Allocation<Tag, Self>,
_ptr: Pointer<Tag>,
_size: Size,
) -> InterpResult<'tcx> {
Ok(())
impl AllocError {
pub fn to_interp_error<'tcx>(self, alloc_id: AllocId) -> InterpError<'tcx> {
match self {
AllocError::ReadPointerAsBytes => {
InterpError::Unsupported(UnsupportedOpInfo::ReadPointerAsBytes)
}
AllocError::InvalidUninitBytes(info) => InterpError::UndefinedBehavior(
UndefinedBehaviorInfo::InvalidUninitBytes(info.map(|b| (alloc_id, b))),
),
}
}
}
// For `Tag = ()` and no extra state, we have a trivial implementation.
impl AllocationExtra<()> for () {}
/// The information that makes up a memory access: offset and size.
#[derive(Copy, Clone, Debug)]
pub struct AllocRange {
pub start: Size,
pub size: Size,
}
/// Free-starting constructor for less syntactic overhead.
#[inline(always)]
pub fn alloc_range(start: Size, size: Size) -> AllocRange {
AllocRange { start, size }
}
impl AllocRange {
#[inline(always)]
pub fn end(self) -> Size {
self.start + self.size // This does overflow checking.
}
/// Returns the `subrange` within this range; panics if it is not a subrange.
#[inline]
pub fn subrange(self, subrange: AllocRange) -> AllocRange {
let sub_start = self.start + subrange.start;
let range = alloc_range(sub_start, subrange.size);
assert!(range.end() <= self.end(), "access outside the bounds for given AllocRange");
range
}
}
// The constructors are all without extra; the extra gets added by a machine hook later.
impl<Tag> Allocation<Tag> {
@ -99,7 +114,7 @@ impl<Tag> Allocation<Tag> {
}
pub fn from_byte_aligned_bytes<'a>(slice: impl Into<Cow<'a, [u8]>>) -> Self {
Allocation::from_bytes(slice, Align::from_bytes(1).unwrap())
Allocation::from_bytes(slice, Align::ONE)
}
pub fn uninit(size: Size, align: Align) -> Self {
@ -114,7 +129,7 @@ impl<Tag> Allocation<Tag> {
}
}
impl Allocation<(), ()> {
impl Allocation<()> {
/// Add Tag and Extra fields
pub fn with_tags_and_extra<T, E>(
self,
@ -154,7 +169,7 @@ impl<Tag, Extra> Allocation<Tag, Extra> {
/// Looks at a slice which may describe uninitialized bytes or describe a relocation. This differs
/// from `get_bytes_with_uninit_and_ptr` in that it does no relocation checks (even on the
/// edges) at all. It further ignores `AllocationExtra` callbacks.
/// edges) at all.
/// This must not be used for reads affecting the interpreter execution.
pub fn inspect_with_uninit_and_ptr_outside_interpreter(&self, range: Range<usize>) -> &[u8] {
&self.bytes[range]
@ -172,23 +187,7 @@ impl<Tag, Extra> Allocation<Tag, Extra> {
}
/// Byte accessors.
impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
/// Just a small local helper function to avoid a bit of code repetition.
/// Returns the range of this allocation that was meant.
#[inline]
fn check_bounds(&self, offset: Size, size: Size) -> Range<usize> {
let end = offset + size; // This does overflow checking.
let end = usize::try_from(end.bytes()).expect("access too big for this host architecture");
assert!(
end <= self.len(),
"Out-of-bounds access at offset {}, size {} in allocation of size {}",
offset.bytes(),
size.bytes(),
self.len()
);
offset.bytes_usize()..end
}
impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
/// The last argument controls whether we error out when there are uninitialized
/// or pointer bytes. You should never call this, call `get_bytes` or
/// `get_bytes_with_uninit_and_ptr` instead,
@ -201,23 +200,18 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
fn get_bytes_internal(
&self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
size: Size,
range: AllocRange,
check_init_and_ptr: bool,
) -> InterpResult<'tcx, &[u8]> {
let range = self.check_bounds(ptr.offset, size);
) -> AllocResult<&[u8]> {
if check_init_and_ptr {
self.check_init(ptr, size)?;
self.check_relocations(cx, ptr, size)?;
self.check_init(range)?;
self.check_relocations(cx, range)?;
} else {
// We still don't want relocations on the *edges*.
self.check_relocation_edges(cx, ptr, size)?;
self.check_relocation_edges(cx, range)?;
}
AllocationExtra::memory_read(self, ptr, size)?;
Ok(&self.bytes[range])
Ok(&self.bytes[range.start.bytes_usize()..range.end().bytes_usize()])
}
/// Checks that these bytes are initialized and not pointer bytes, and then return them
@ -227,13 +221,8 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
/// Most likely, you want to use the `PlaceTy` and `OperandTy`-based methods
/// on `InterpCx` instead.
#[inline]
pub fn get_bytes(
&self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
size: Size,
) -> InterpResult<'tcx, &[u8]> {
self.get_bytes_internal(cx, ptr, size, true)
pub fn get_bytes(&self, cx: &impl HasDataLayout, range: AllocRange) -> AllocResult<&[u8]> {
self.get_bytes_internal(cx, range, true)
}
/// It is the caller's responsibility to handle uninitialized and pointer bytes.
@ -244,10 +233,9 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
pub fn get_bytes_with_uninit_and_ptr(
&self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
size: Size,
) -> InterpResult<'tcx, &[u8]> {
self.get_bytes_internal(cx, ptr, size, false)
range: AllocRange,
) -> AllocResult<&[u8]> {
self.get_bytes_internal(cx, range, false)
}
/// Just calling this already marks everything as defined and removes relocations,
@ -256,69 +244,46 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
/// It is the caller's responsibility to check bounds and alignment beforehand.
/// Most likely, you want to use the `PlaceTy` and `OperandTy`-based methods
/// on `InterpCx` instead.
pub fn get_bytes_mut(
&mut self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
size: Size,
) -> InterpResult<'tcx, &mut [u8]> {
let range = self.check_bounds(ptr.offset, size);
pub fn get_bytes_mut(&mut self, cx: &impl HasDataLayout, range: AllocRange) -> &mut [u8] {
self.mark_init(range, true);
self.clear_relocations(cx, range);
self.mark_init(ptr, size, true);
self.clear_relocations(cx, ptr, size);
&mut self.bytes[range.start.bytes_usize()..range.end().bytes_usize()]
}
AllocationExtra::memory_written(self, ptr, size)?;
/// A raw pointer variant of `get_bytes_mut` that avoids invalidating existing aliases into this memory.
pub fn get_bytes_mut_ptr(&mut self, cx: &impl HasDataLayout, range: AllocRange) -> *mut [u8] {
self.mark_init(range, true);
self.clear_relocations(cx, range);
Ok(&mut self.bytes[range])
assert!(range.end().bytes_usize() <= self.bytes.len()); // need to do our own bounds-check
let begin_ptr = self.bytes.as_mut_ptr().wrapping_add(range.start.bytes_usize());
let len = range.end().bytes_usize() - range.start.bytes_usize();
ptr::slice_from_raw_parts_mut(begin_ptr, len)
}
}
/// Reading and writing.
impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
/// Validates that `ptr.offset` and `ptr.offset + size` do not point to the middle of a
/// relocation. If `allow_uninit_and_ptr` is `false`, also enforces that the memory in the
/// given range contains neither relocations nor uninitialized bytes.
pub fn check_bytes(
&self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
size: Size,
range: AllocRange,
allow_uninit_and_ptr: bool,
) -> InterpResult<'tcx> {
) -> AllocResult {
// Check bounds and relocations on the edges.
self.get_bytes_with_uninit_and_ptr(cx, ptr, size)?;
self.get_bytes_with_uninit_and_ptr(cx, range)?;
// Check uninit and ptr.
if !allow_uninit_and_ptr {
self.check_init(ptr, size)?;
self.check_relocations(cx, ptr, size)?;
self.check_init(range)?;
self.check_relocations(cx, range)?;
}
Ok(())
}
/// Writes `src` to the memory starting at `ptr.offset`.
///
/// It is the caller's responsibility to check bounds and alignment beforehand.
/// Most likely, you want to call `Memory::write_bytes` instead of this method.
pub fn write_bytes(
&mut self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
src: impl IntoIterator<Item = u8>,
) -> InterpResult<'tcx> {
let mut src = src.into_iter();
let (lower, upper) = src.size_hint();
let len = upper.expect("can only write bounded iterators");
assert_eq!(lower, len, "can only write iterators with a precise length");
let bytes = self.get_bytes_mut(cx, ptr, Size::from_bytes(len))?;
// `zip` would stop when the first iterator ends; we want to definitely
// cover all of `bytes`.
for dest in bytes {
*dest = src.next().expect("iterator was shorter than it said it would be");
}
assert_matches!(src.next(), None, "iterator was longer than it said it would be");
Ok(())
}
/// Reads a *non-ZST* scalar.
///
/// ZSTs can't be read because in order to obtain a `Pointer`, we need to check
@ -329,14 +294,13 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
pub fn read_scalar(
&self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
size: Size,
) -> InterpResult<'tcx, ScalarMaybeUninit<Tag>> {
range: AllocRange,
) -> AllocResult<ScalarMaybeUninit<Tag>> {
// `get_bytes_unchecked` tests relocation edges.
let bytes = self.get_bytes_with_uninit_and_ptr(cx, ptr, size)?;
let bytes = self.get_bytes_with_uninit_and_ptr(cx, range)?;
// Uninit check happens *after* we established that the alignment is correct.
// We must not return `Ok()` for unaligned pointers!
if self.is_init(ptr, size).is_err() {
if self.is_init(range).is_err() {
// This inflates uninitialized bytes to the entire scalar, even if only a few
// bytes are uninitialized.
return Ok(ScalarMaybeUninit::Uninit);
@ -344,29 +308,19 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
// Now we do the actual reading.
let bits = read_target_uint(cx.data_layout().endian, bytes).unwrap();
// See if we got a pointer.
if size != cx.data_layout().pointer_size {
if range.size != cx.data_layout().pointer_size {
// Not a pointer.
// *Now*, we better make sure that the inside is free of relocations too.
self.check_relocations(cx, ptr, size)?;
self.check_relocations(cx, range)?;
} else {
if let Some(&(tag, alloc_id)) = self.relocations.get(&ptr.offset) {
// Maybe a pointer.
if let Some(&(tag, alloc_id)) = self.relocations.get(&range.start) {
let ptr = Pointer::new_with_tag(alloc_id, Size::from_bytes(bits), tag);
return Ok(ScalarMaybeUninit::Scalar(ptr.into()));
}
}
// We don't. Just return the bits.
Ok(ScalarMaybeUninit::Scalar(Scalar::from_uint(bits, size)))
}
/// Reads a pointer-sized scalar.
///
/// It is the caller's responsibility to check bounds and alignment beforehand.
/// Most likely, you want to call `InterpCx::read_scalar` instead of this method.
pub fn read_ptr_sized(
&self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
) -> InterpResult<'tcx, ScalarMaybeUninit<Tag>> {
self.read_scalar(cx, ptr, cx.data_layout().pointer_size)
Ok(ScalarMaybeUninit::Scalar(Scalar::from_uint(bits, range.size)))
}
/// Writes a *non-ZST* scalar.
@ -379,78 +333,56 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
pub fn write_scalar(
&mut self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
range: AllocRange,
val: ScalarMaybeUninit<Tag>,
type_size: Size,
) -> InterpResult<'tcx> {
) -> AllocResult {
let val = match val {
ScalarMaybeUninit::Scalar(scalar) => scalar,
ScalarMaybeUninit::Uninit => {
self.mark_init(ptr, type_size, false);
self.mark_init(range, false);
return Ok(());
}
};
let bytes = match val.to_bits_or_ptr(type_size, cx) {
let bytes = match val.to_bits_or_ptr(range.size, cx) {
Err(val) => u128::from(val.offset.bytes()),
Ok(data) => data,
};
let endian = cx.data_layout().endian;
let dst = self.get_bytes_mut(cx, ptr, type_size)?;
let dst = self.get_bytes_mut(cx, range);
write_target_uint(endian, dst, bytes).unwrap();
// See if we have to also write a relocation.
if let Scalar::Ptr(val) = val {
self.relocations.insert(ptr.offset, (val.tag, val.alloc_id));
self.relocations.insert(range.start, (val.tag, val.alloc_id));
}
Ok(())
}
/// Writes a pointer-sized scalar.
///
/// It is the caller's responsibility to check bounds and alignment beforehand.
/// Most likely, you want to call `InterpCx::write_scalar` instead of this method.
pub fn write_ptr_sized(
&mut self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
val: ScalarMaybeUninit<Tag>,
) -> InterpResult<'tcx> {
let ptr_size = cx.data_layout().pointer_size;
self.write_scalar(cx, ptr, val, ptr_size)
}
}
/// Relocations.
impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
/// Returns all relocations overlapping with the given pointer-offset pair.
pub fn get_relocations(
&self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
size: Size,
range: AllocRange,
) -> &[(Size, (Tag, AllocId))] {
// We have to go back `pointer_size - 1` bytes, as that one would still overlap with
// the beginning of this range.
let start = ptr.offset.bytes().saturating_sub(cx.data_layout().pointer_size.bytes() - 1);
let end = ptr.offset + size; // This does overflow checking.
self.relocations.range(Size::from_bytes(start)..end)
let start = range.start.bytes().saturating_sub(cx.data_layout().pointer_size.bytes() - 1);
self.relocations.range(Size::from_bytes(start)..range.end())
}
/// Checks that there are no relocations overlapping with the given range.
#[inline(always)]
fn check_relocations(
&self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
size: Size,
) -> InterpResult<'tcx> {
if self.get_relocations(cx, ptr, size).is_empty() {
fn check_relocations(&self, cx: &impl HasDataLayout, range: AllocRange) -> AllocResult {
if self.get_relocations(cx, range).is_empty() {
Ok(())
} else {
throw_unsup!(ReadPointerAsBytes)
Err(AllocError::ReadPointerAsBytes)
}
}
@ -460,11 +392,11 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
/// uninitialized. This is a somewhat odd "spooky action at a distance",
/// but it allows strictly more code to run than if we would just error
/// immediately in that case.
fn clear_relocations(&mut self, cx: &impl HasDataLayout, ptr: Pointer<Tag>, size: Size) {
fn clear_relocations(&mut self, cx: &impl HasDataLayout, range: AllocRange) {
// Find the start and end of the given range and its outermost relocations.
let (first, last) = {
// Find all relocations overlapping the given range.
let relocations = self.get_relocations(cx, ptr, size);
let relocations = self.get_relocations(cx, range);
if relocations.is_empty() {
return;
}
@ -474,8 +406,8 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
relocations.last().unwrap().0 + cx.data_layout().pointer_size,
)
};
let start = ptr.offset;
let end = start + size; // `Size` addition
let start = range.start;
let end = range.end();
// Mark parts of the outermost relocations as uninitialized if they partially fall outside the
// given range.
@ -493,46 +425,41 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
/// Errors if there are relocations overlapping with the edges of the
/// given memory range.
#[inline]
fn check_relocation_edges(
&self,
cx: &impl HasDataLayout,
ptr: Pointer<Tag>,
size: Size,
) -> InterpResult<'tcx> {
self.check_relocations(cx, ptr, Size::ZERO)?;
self.check_relocations(cx, ptr.offset(size, cx)?, Size::ZERO)?;
fn check_relocation_edges(&self, cx: &impl HasDataLayout, range: AllocRange) -> AllocResult {
self.check_relocations(cx, alloc_range(range.start, Size::ZERO))?;
self.check_relocations(cx, alloc_range(range.end(), Size::ZERO))?;
Ok(())
}
}
/// Uninitialized bytes.
impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
/// Checks whether the given range is entirely initialized.
///
/// Returns `Ok(())` if it's initialized. Otherwise returns the range of byte
/// indexes of the first contiguous uninitialized access.
fn is_init(&self, ptr: Pointer<Tag>, size: Size) -> Result<(), Range<Size>> {
self.init_mask.is_range_initialized(ptr.offset, ptr.offset + size) // `Size` addition
fn is_init(&self, range: AllocRange) -> Result<(), Range<Size>> {
self.init_mask.is_range_initialized(range.start, range.end()) // `Size` addition
}
/// Checks that a range of bytes is initialized. If not, returns the `InvalidUninitBytes`
/// error which will report the first range of bytes which is uninitialized.
fn check_init(&self, ptr: Pointer<Tag>, size: Size) -> InterpResult<'tcx> {
self.is_init(ptr, size).or_else(|idx_range| {
throw_ub!(InvalidUninitBytes(Some(UninitBytesAccess {
access_ptr: ptr.erase_tag(),
access_size: size,
uninit_ptr: Pointer::new(ptr.alloc_id, idx_range.start),
fn check_init(&self, range: AllocRange) -> AllocResult {
self.is_init(range).or_else(|idx_range| {
Err(AllocError::InvalidUninitBytes(Some(UninitBytesAccess {
access_offset: range.start,
access_size: range.size,
uninit_offset: idx_range.start,
uninit_size: idx_range.end - idx_range.start, // `Size` subtraction
})))
})
}
pub fn mark_init(&mut self, ptr: Pointer<Tag>, size: Size, is_init: bool) {
if size.bytes() == 0 {
pub fn mark_init(&mut self, range: AllocRange, is_init: bool) {
if range.size.bytes() == 0 {
return;
}
self.init_mask.set_range(ptr.offset, ptr.offset + size, is_init);
self.init_mask.set_range(range.start, range.end(), is_init);
}
}
@ -667,25 +594,25 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
pub fn prepare_relocation_copy(
&self,
cx: &impl HasDataLayout,
src: Pointer<Tag>,
size: Size,
dest: Pointer<Tag>,
length: u64,
src: AllocRange,
dest: Size,
count: u64,
) -> AllocationRelocations<Tag> {
let relocations = self.get_relocations(cx, src, size);
let relocations = self.get_relocations(cx, src);
if relocations.is_empty() {
return AllocationRelocations { relative_relocations: Vec::new() };
}
let mut new_relocations = Vec::with_capacity(relocations.len() * (length as usize));
let size = src.size;
let mut new_relocations = Vec::with_capacity(relocations.len() * (count as usize));
for i in 0..length {
for i in 0..count {
new_relocations.extend(relocations.iter().map(|&(offset, reloc)| {
// compute offset for current repetition
let dest_offset = dest.offset + size * i; // `Size` operations
let dest_offset = dest + size * i; // `Size` operations
(
// shift offsets from source allocation to destination allocation
(offset + dest_offset) - src.offset, // `Size` operations
(offset + dest_offset) - src.start, // `Size` operations
reloc,
)
}));

14
compiler/rustc_middle/src/mir/interpret/error.rs
View file

@ -198,11 +198,11 @@ impl fmt::Display for CheckInAllocMsg {
#[derive(Debug)]
pub struct UninitBytesAccess {
/// Location of the original memory access.
pub access_ptr: Pointer,
pub access_offset: Size,
/// Size of the original memory access.
pub access_size: Size,
/// Location of the first uninitialized byte that was accessed.
pub uninit_ptr: Pointer,
pub uninit_offset: Size,
/// Number of consecutive uninitialized bytes that were accessed.
pub uninit_size: Size,
}
@ -264,7 +264,7 @@ pub enum UndefinedBehaviorInfo<'tcx> {
/// Using a string that is not valid UTF-8,
InvalidStr(std::str::Utf8Error),
/// Using uninitialized data where it is not allowed.
InvalidUninitBytes(Option<UninitBytesAccess>),
InvalidUninitBytes(Option<(AllocId, UninitBytesAccess)>),
/// Working with a local that is not currently live.
DeadLocal,
/// Data size is not equal to target size.
@ -335,18 +335,18 @@ impl fmt::Display for UndefinedBehaviorInfo<'_> {
write!(f, "using {} as function pointer but it does not point to a function", p)
}
InvalidStr(err) => write!(f, "this string is not valid UTF-8: {}", err),
InvalidUninitBytes(Some(access)) => write!(
InvalidUninitBytes(Some((alloc, access))) => write!(
f,
"reading {} byte{} of memory starting at {}, \
but {} byte{} {} uninitialized starting at {}, \
and this operation requires initialized memory",
access.access_size.bytes(),
pluralize!(access.access_size.bytes()),
access.access_ptr,
Pointer::new(*alloc, access.access_offset),
access.uninit_size.bytes(),
pluralize!(access.uninit_size.bytes()),
if access.uninit_size.bytes() != 1 { "are" } else { "is" },
access.uninit_ptr,
Pointer::new(*alloc, access.uninit_offset),
),
InvalidUninitBytes(None) => write!(
f,
@ -446,7 +446,7 @@ impl dyn MachineStopType {
}
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
static_assert_size!(InterpError<'_>, 72);
static_assert_size!(InterpError<'_>, 64);
pub enum InterpError<'tcx> {
/// The program caused undefined behavior.

2
compiler/rustc_middle/src/mir/interpret/mod.rs
View file

@ -125,7 +125,7 @@ pub use self::error::{
pub use self::value::{get_slice_bytes, ConstAlloc, ConstValue, Scalar, ScalarMaybeUninit};
pub use self::allocation::{Allocation, AllocationExtra, InitMask, Relocations};
pub use self::allocation::{alloc_range, AllocRange, Allocation, InitMask, Relocations};
pub use self::pointer::{Pointer, PointerArithmetic};

6
compiler/rustc_middle/src/mir/interpret/value.rs
View file

@ -10,7 +10,7 @@ use rustc_target::abi::{HasDataLayout, Size, TargetDataLayout};
use crate::ty::{Lift, ParamEnv, ScalarInt, Ty, TyCtxt};
use super::{AllocId, Allocation, InterpResult, Pointer, PointerArithmetic};
use super::{AllocId, AllocRange, Allocation, InterpResult, Pointer, PointerArithmetic};
/// Represents the result of const evaluation via the `eval_to_allocation` query.
#[derive(Copy, Clone, HashStable, TyEncodable, TyDecodable, Debug, Hash, Eq, PartialEq)]
@ -661,9 +661,7 @@ pub fn get_slice_bytes<'tcx>(cx: &impl HasDataLayout, val: ConstValue<'tcx>) ->
let len = end - start;
data.get_bytes(
cx,
// invent a pointer, only the offset is relevant anyway
Pointer::new(AllocId(0), Size::from_bytes(start)),
Size::from_bytes(len),
AllocRange { start: Size::from_bytes(start), size: Size::from_bytes(len) },
)
.unwrap_or_else(|err| bug!("const slice is invalid: {:?}", err))
} else {

13
compiler/rustc_middle/src/ty/print/pretty.rs
View file

@ -1,5 +1,5 @@
use crate::middle::cstore::{ExternCrate, ExternCrateSource};
use crate::mir::interpret::{AllocId, ConstValue, GlobalAlloc, Pointer, Scalar};
use crate::mir::interpret::{AllocRange, ConstValue, GlobalAlloc, Pointer, Scalar};
use crate::ty::subst::{GenericArg, GenericArgKind, Subst};
use crate::ty::{self, ConstInt, DefIdTree, ParamConst, ScalarInt, Ty, TyCtxt, TypeFoldable};
use rustc_apfloat::ieee::{Double, Single};
@ -1004,9 +1004,9 @@ pub trait PrettyPrinter<'tcx>:
_,
) => match self.tcx().get_global_alloc(ptr.alloc_id) {
Some(GlobalAlloc::Memory(alloc)) => {
let bytes = int.assert_bits(self.tcx().data_layout.pointer_size);
let size = Size::from_bytes(bytes);
if let Ok(byte_str) = alloc.get_bytes(&self.tcx(), ptr, size) {
let len = int.assert_bits(self.tcx().data_layout.pointer_size);
let range = AllocRange { start: ptr.offset, size: Size::from_bytes(len) };
if let Ok(byte_str) = alloc.get_bytes(&self.tcx(), range) {
p!(pretty_print_byte_str(byte_str))
} else {
p!("<too short allocation>")
@ -1181,10 +1181,9 @@ pub trait PrettyPrinter<'tcx>:
(ConstValue::ByRef { alloc, offset }, ty::Array(t, n)) if *t == u8_type => {
let n = n.val.try_to_bits(self.tcx().data_layout.pointer_size).unwrap();
// cast is ok because we already checked for pointer size (32 or 64 bit) above
let n = Size::from_bytes(n);
let ptr = Pointer::new(AllocId(0), offset);
let range = AllocRange { start: offset, size: Size::from_bytes(n) };
let byte_str = alloc.get_bytes(&self.tcx(), ptr, n).unwrap();
let byte_str = alloc.get_bytes(&self.tcx(), range).unwrap();
p!("*");
p!(pretty_print_byte_str(byte_str));
Ok(self)