/
memory.rs
1169 lines (1069 loc) · 43.5 KB
/
memory.rs
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// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! The memory subsystem.
//!
//! Generally, we use `Pointer` to denote memory addresses. However, some operations
//! have a "size"-like parameter, and they take `Scalar` for the address because
//! if the size is 0, then the pointer can also be a (properly aligned, non-NULL)
//! integer. It is crucial that these operations call `check_align` *before*
//! short-circuiting the empty case!
use std::collections::VecDeque;
use std::ptr;
use std::borrow::Cow;
use rustc::ty::{self, Instance, ParamEnv, query::TyCtxtAt};
use rustc::ty::layout::{self, Align, TargetDataLayout, Size, HasDataLayout};
pub use rustc::mir::interpret::{truncate, write_target_uint, read_target_uint};
use rustc_data_structures::fx::{FxHashSet, FxHashMap};
use syntax::ast::Mutability;
use super::{
Pointer, AllocId, Allocation, ConstValue, GlobalId,
EvalResult, Scalar, EvalErrorKind, AllocType, PointerArithmetic,
Machine, MemoryAccess, AllocMap, MayLeak, ScalarMaybeUndef,
};
#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash)]
pub enum MemoryKind<T> {
/// Error if deallocated except during a stack pop
Stack,
/// Error if ever deallocated
Vtable,
/// Additional memory kinds a machine wishes to distinguish from the builtin ones
Machine(T),
}
impl<T: MayLeak> MayLeak for MemoryKind<T> {
#[inline]
fn may_leak(self) -> bool {
match self {
MemoryKind::Stack => false,
MemoryKind::Vtable => true,
MemoryKind::Machine(k) => k.may_leak()
}
}
}
// `Memory` has to depend on the `Machine` because some of its operations
// (e.g. `get`) call a `Machine` hook.
pub struct Memory<'a, 'mir, 'tcx: 'a + 'mir, M: Machine<'a, 'mir, 'tcx>> {
/// Allocations local to this instance of the miri engine. The kind
/// helps ensure that the same mechanism is used for allocation and
/// deallocation. When an allocation is not found here, it is a
/// static and looked up in the `tcx` for read access. Some machines may
/// have to mutate this map even on a read-only access to a static (because
/// they do pointer provenance tracking and the allocations in `tcx` have
/// the wrong type), so we let the machine override this type.
/// Either way, if the machine allows writing to a static, doing so will
/// create a copy of the static allocation here.
alloc_map: M::MemoryMap,
/// To be able to compare pointers with NULL, and to check alignment for accesses
/// to ZSTs (where pointers may dangle), we keep track of the size even for allocations
/// that do not exist any more.
dead_alloc_map: FxHashMap<AllocId, (Size, Align)>,
/// Lets us implement `HasDataLayout`, which is awfully convenient.
pub(super) tcx: TyCtxtAt<'a, 'tcx, 'tcx>,
}
impl<'b, 'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> HasDataLayout
for &'b Memory<'a, 'mir, 'tcx, M>
{
#[inline]
fn data_layout(&self) -> &TargetDataLayout {
&self.tcx.data_layout
}
}
impl<'a, 'b, 'c, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> HasDataLayout
for &'b &'c mut Memory<'a, 'mir, 'tcx, M>
{
#[inline]
fn data_layout(&self) -> &TargetDataLayout {
&self.tcx.data_layout
}
}
// FIXME: Really we shouldnt clone memory, ever. Snapshot machinery should instad
// carefully copy only the reachable parts.
impl<'a, 'mir, 'tcx: 'a + 'mir, M: Machine<'a, 'mir, 'tcx>>
Clone for Memory<'a, 'mir, 'tcx, M>
{
fn clone(&self) -> Self {
Memory {
alloc_map: self.alloc_map.clone(),
dead_alloc_map: self.dead_alloc_map.clone(),
tcx: self.tcx,
}
}
}
impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
pub fn new(tcx: TyCtxtAt<'a, 'tcx, 'tcx>) -> Self {
Memory {
alloc_map: Default::default(),
dead_alloc_map: FxHashMap::default(),
tcx,
}
}
pub fn create_fn_alloc(&mut self, instance: Instance<'tcx>) -> Pointer<M::PointerTag> {
Pointer::from(self.tcx.alloc_map.lock().create_fn_alloc(instance)).with_default_tag()
}
pub fn allocate_static_bytes(&mut self, bytes: &[u8]) -> Pointer<M::PointerTag> {
Pointer::from(self.tcx.allocate_bytes(bytes)).with_default_tag()
}
pub fn allocate_with(
&mut self,
alloc: Allocation<M::PointerTag, M::AllocExtra>,
kind: MemoryKind<M::MemoryKinds>,
) -> EvalResult<'tcx, AllocId> {
let id = self.tcx.alloc_map.lock().reserve();
self.alloc_map.insert(id, (kind, alloc));
Ok(id)
}
pub fn allocate(
&mut self,
size: Size,
align: Align,
kind: MemoryKind<M::MemoryKinds>,
) -> EvalResult<'tcx, Pointer<M::PointerTag>> {
let ptr = Pointer::from(self.allocate_with(Allocation::undef(size, align), kind)?);
Ok(ptr.with_default_tag())
}
pub fn reallocate(
&mut self,
ptr: Pointer<M::PointerTag>,
old_size: Size,
old_align: Align,
new_size: Size,
new_align: Align,
kind: MemoryKind<M::MemoryKinds>,
) -> EvalResult<'tcx, Pointer<M::PointerTag>> {
if ptr.offset.bytes() != 0 {
return err!(ReallocateNonBasePtr);
}
// For simplicities' sake, we implement reallocate as "alloc, copy, dealloc"
let new_ptr = self.allocate(new_size, new_align, kind)?;
self.copy(
ptr.into(),
old_align,
new_ptr.into(),
new_align,
old_size.min(new_size),
/*nonoverlapping*/ true,
)?;
self.deallocate(ptr, Some((old_size, old_align)), kind)?;
Ok(new_ptr)
}
/// Deallocate a local, or do nothing if that local has been made into a static
pub fn deallocate_local(&mut self, ptr: Pointer<M::PointerTag>) -> EvalResult<'tcx> {
// The allocation might be already removed by static interning.
// This can only really happen in the CTFE instance, not in miri.
if self.alloc_map.contains_key(&ptr.alloc_id) {
self.deallocate(ptr, None, MemoryKind::Stack)
} else {
Ok(())
}
}
pub fn deallocate(
&mut self,
ptr: Pointer<M::PointerTag>,
size_and_align: Option<(Size, Align)>,
kind: MemoryKind<M::MemoryKinds>,
) -> EvalResult<'tcx> {
trace!("deallocating: {}", ptr.alloc_id);
if ptr.offset.bytes() != 0 {
return err!(DeallocateNonBasePtr);
}
let (alloc_kind, mut alloc) = match self.alloc_map.remove(&ptr.alloc_id) {
Some(alloc) => alloc,
None => {
// Deallocating static memory -- always an error
return match self.tcx.alloc_map.lock().get(ptr.alloc_id) {
Some(AllocType::Function(..)) => err!(DeallocatedWrongMemoryKind(
"function".to_string(),
format!("{:?}", kind),
)),
Some(AllocType::Static(..)) |
Some(AllocType::Memory(..)) => err!(DeallocatedWrongMemoryKind(
"static".to_string(),
format!("{:?}", kind),
)),
None => err!(DoubleFree)
}
}
};
if alloc_kind != kind {
return err!(DeallocatedWrongMemoryKind(
format!("{:?}", alloc_kind),
format!("{:?}", kind),
));
}
if let Some((size, align)) = size_and_align {
if size.bytes() != alloc.bytes.len() as u64 || align != alloc.align {
let bytes = Size::from_bytes(alloc.bytes.len() as u64);
return err!(IncorrectAllocationInformation(size,
bytes,
align,
alloc.align));
}
}
// Let the machine take some extra action
M::memory_deallocated(&mut alloc, ptr)?;
// Don't forget to remember size and align of this now-dead allocation
let old = self.dead_alloc_map.insert(
ptr.alloc_id,
(Size::from_bytes(alloc.bytes.len() as u64), alloc.align)
);
if old.is_some() {
bug!("Nothing can be deallocated twice");
}
Ok(())
}
/// Check that the pointer is aligned AND non-NULL. This supports ZSTs in two ways:
/// You can pass a scalar, and a `Pointer` does not have to actually still be allocated.
pub fn check_align(
&self,
ptr: Scalar<M::PointerTag>,
required_align: Align
) -> EvalResult<'tcx> {
// Check non-NULL/Undef, extract offset
let (offset, alloc_align) = match ptr {
Scalar::Ptr(ptr) => {
let (size, align) = self.get_size_and_align(ptr.alloc_id);
// check this is not NULL -- which we can ensure only if this is in-bounds
// of some (potentially dead) allocation.
if ptr.offset > size {
return err!(PointerOutOfBounds {
ptr: ptr.erase_tag(),
access: true,
allocation_size: size,
});
};
// keep data for alignment check
(ptr.offset.bytes(), align)
}
Scalar::Bits { bits, size } => {
assert_eq!(size as u64, self.pointer_size().bytes());
assert!(bits < (1u128 << self.pointer_size().bits()));
// check this is not NULL
if bits == 0 {
return err!(InvalidNullPointerUsage);
}
// the "base address" is 0 and hence always aligned
(bits as u64, required_align)
}
};
// Check alignment
if alloc_align.abi() < required_align.abi() {
return err!(AlignmentCheckFailed {
has: alloc_align,
required: required_align,
});
}
if offset % required_align.abi() == 0 {
Ok(())
} else {
let has = offset % required_align.abi();
err!(AlignmentCheckFailed {
has: Align::from_bytes(has, has).unwrap(),
required: required_align,
})
}
}
/// Check if the pointer is "in-bounds". Notice that a pointer pointing at the end
/// of an allocation (i.e., at the first *inaccessible* location) *is* considered
/// in-bounds! This follows C's/LLVM's rules. The `access` boolean is just used
/// for the error message.
/// If you want to check bounds before doing a memory access, be sure to
/// check the pointer one past the end of your access, then everything will
/// work out exactly.
pub fn check_bounds_ptr(&self, ptr: Pointer<M::PointerTag>, access: bool) -> EvalResult<'tcx> {
let alloc = self.get(ptr.alloc_id)?;
let allocation_size = alloc.bytes.len() as u64;
if ptr.offset.bytes() > allocation_size {
return err!(PointerOutOfBounds {
ptr: ptr.erase_tag(),
access,
allocation_size: Size::from_bytes(allocation_size),
});
}
Ok(())
}
/// Check if the memory range beginning at `ptr` and of size `Size` is "in-bounds".
#[inline(always)]
pub fn check_bounds(
&self,
ptr: Pointer<M::PointerTag>,
size: Size,
access: bool
) -> EvalResult<'tcx> {
// if ptr.offset is in bounds, then so is ptr (because offset checks for overflow)
self.check_bounds_ptr(ptr.offset(size, &*self)?, access)
}
}
/// Allocation accessors
impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
/// Helper function to obtain the global (tcx) allocation for a static.
/// This attempts to return a reference to an existing allocation if
/// one can be found in `tcx`. That, however, is only possible if `tcx` and
/// this machine use the same pointer tag, so it is indirected through
/// `M::static_with_default_tag`.
fn get_static_alloc(
tcx: TyCtxtAt<'a, 'tcx, 'tcx>,
id: AllocId,
) -> EvalResult<'tcx, Cow<'tcx, Allocation<M::PointerTag, M::AllocExtra>>> {
let alloc = tcx.alloc_map.lock().get(id);
let def_id = match alloc {
Some(AllocType::Memory(mem)) => {
// We got tcx memory. Let the machine figure out whether and how to
// turn that into memory with the right pointer tag.
return Ok(M::static_with_default_tag(mem))
}
Some(AllocType::Function(..)) => {
return err!(DerefFunctionPointer)
}
Some(AllocType::Static(did)) => {
did
}
None =>
return err!(DanglingPointerDeref),
};
// We got a "lazy" static that has not been computed yet, do some work
trace!("static_alloc: Need to compute {:?}", def_id);
if tcx.is_foreign_item(def_id) {
return M::find_foreign_static(tcx, def_id);
}
let instance = Instance::mono(tcx.tcx, def_id);
let gid = GlobalId {
instance,
promoted: None,
};
tcx.const_eval(ty::ParamEnv::reveal_all().and(gid)).map_err(|err| {
// no need to report anything, the const_eval call takes care of that for statics
assert!(tcx.is_static(def_id).is_some());
EvalErrorKind::ReferencedConstant(err).into()
}).map(|const_val| {
if let ConstValue::ByRef(_, allocation, _) = const_val.val {
// We got tcx memory. Let the machine figure out whether and how to
// turn that into memory with the right pointer tag.
M::static_with_default_tag(allocation)
} else {
bug!("Matching on non-ByRef static")
}
})
}
pub fn get(&self, id: AllocId) -> EvalResult<'tcx, &Allocation<M::PointerTag, M::AllocExtra>> {
// The error type of the inner closure here is somewhat funny. We have two
// ways of "erroring": An actual error, or because we got a reference from
// `get_static_alloc` that we can actually use directly without inserting anything anywhere.
// So the error type is `EvalResult<'tcx, &Allocation<M::PointerTag>>`.
let a = self.alloc_map.get_or(id, || {
let alloc = Self::get_static_alloc(self.tcx, id).map_err(Err)?;
match alloc {
Cow::Borrowed(alloc) => {
// We got a ref, cheaply return that as an "error" so that the
// map does not get mutated.
Err(Ok(alloc))
}
Cow::Owned(alloc) => {
// Need to put it into the map and return a ref to that
let kind = M::STATIC_KIND.expect(
"I got an owned allocation that I have to copy but the machine does \
not expect that to happen"
);
Ok((MemoryKind::Machine(kind), alloc))
}
}
});
// Now unpack that funny error type
match a {
Ok(a) => Ok(&a.1),
Err(a) => a
}
}
pub fn get_mut(
&mut self,
id: AllocId,
) -> EvalResult<'tcx, &mut Allocation<M::PointerTag, M::AllocExtra>> {
let tcx = self.tcx;
let a = self.alloc_map.get_mut_or(id, || {
// Need to make a copy, even if `get_static_alloc` is able
// to give us a cheap reference.
let alloc = Self::get_static_alloc(tcx, id)?;
if alloc.mutability == Mutability::Immutable {
return err!(ModifiedConstantMemory);
}
let kind = M::STATIC_KIND.expect(
"An allocation is being mutated but the machine does not expect that to happen"
);
Ok((MemoryKind::Machine(kind), alloc.into_owned()))
});
// Unpack the error type manually because type inference doesn't
// work otherwise (and we cannot help it because `impl Trait`)
match a {
Err(e) => Err(e),
Ok(a) => {
let a = &mut a.1;
if a.mutability == Mutability::Immutable {
return err!(ModifiedConstantMemory);
}
Ok(a)
}
}
}
pub fn get_size_and_align(&self, id: AllocId) -> (Size, Align) {
if let Ok(alloc) = self.get(id) {
return (Size::from_bytes(alloc.bytes.len() as u64), alloc.align);
}
// Could also be a fn ptr or extern static
match self.tcx.alloc_map.lock().get(id) {
Some(AllocType::Function(..)) => (Size::ZERO, Align::from_bytes(1, 1).unwrap()),
Some(AllocType::Static(did)) => {
// The only way `get` couldn't have worked here is if this is an extern static
assert!(self.tcx.is_foreign_item(did));
// Use size and align of the type
let ty = self.tcx.type_of(did);
let layout = self.tcx.layout_of(ParamEnv::empty().and(ty)).unwrap();
(layout.size, layout.align)
}
_ => {
// Must be a deallocated pointer
*self.dead_alloc_map.get(&id).expect(
"allocation missing in dead_alloc_map"
)
}
}
}
pub fn get_fn(&self, ptr: Pointer<M::PointerTag>) -> EvalResult<'tcx, Instance<'tcx>> {
if ptr.offset.bytes() != 0 {
return err!(InvalidFunctionPointer);
}
trace!("reading fn ptr: {}", ptr.alloc_id);
match self.tcx.alloc_map.lock().get(ptr.alloc_id) {
Some(AllocType::Function(instance)) => Ok(instance),
_ => Err(EvalErrorKind::ExecuteMemory.into()),
}
}
pub fn mark_immutable(&mut self, id: AllocId) -> EvalResult<'tcx> {
self.get_mut(id)?.mutability = Mutability::Immutable;
Ok(())
}
/// For debugging, print an allocation and all allocations it points to, recursively.
pub fn dump_alloc(&self, id: AllocId) {
self.dump_allocs(vec![id]);
}
fn dump_alloc_helper<Tag, Extra>(
&self,
allocs_seen: &mut FxHashSet<AllocId>,
allocs_to_print: &mut VecDeque<AllocId>,
mut msg: String,
alloc: &Allocation<Tag, Extra>,
extra: String,
) {
use std::fmt::Write;
let prefix_len = msg.len();
let mut relocations = vec![];
for i in 0..(alloc.bytes.len() as u64) {
let i = Size::from_bytes(i);
if let Some(&(_, target_id)) = alloc.relocations.get(&i) {
if allocs_seen.insert(target_id) {
allocs_to_print.push_back(target_id);
}
relocations.push((i, target_id));
}
if alloc.undef_mask.is_range_defined(i, i + Size::from_bytes(1)).is_ok() {
// this `as usize` is fine, since `i` came from a `usize`
write!(msg, "{:02x} ", alloc.bytes[i.bytes() as usize]).unwrap();
} else {
msg.push_str("__ ");
}
}
trace!(
"{}({} bytes, alignment {}){}",
msg,
alloc.bytes.len(),
alloc.align.abi(),
extra
);
if !relocations.is_empty() {
msg.clear();
write!(msg, "{:1$}", "", prefix_len).unwrap(); // Print spaces.
let mut pos = Size::ZERO;
let relocation_width = (self.pointer_size().bytes() - 1) * 3;
for (i, target_id) in relocations {
// this `as usize` is fine, since we can't print more chars than `usize::MAX`
write!(msg, "{:1$}", "", ((i - pos) * 3).bytes() as usize).unwrap();
let target = format!("({})", target_id);
// this `as usize` is fine, since we can't print more chars than `usize::MAX`
write!(msg, "└{0:─^1$}┘ ", target, relocation_width as usize).unwrap();
pos = i + self.pointer_size();
}
trace!("{}", msg);
}
}
/// For debugging, print a list of allocations and all allocations they point to, recursively.
pub fn dump_allocs(&self, mut allocs: Vec<AllocId>) {
if !log_enabled!(::log::Level::Trace) {
return;
}
allocs.sort();
allocs.dedup();
let mut allocs_to_print = VecDeque::from(allocs);
let mut allocs_seen = FxHashSet::default();
while let Some(id) = allocs_to_print.pop_front() {
let msg = format!("Alloc {:<5} ", format!("{}:", id));
// normal alloc?
match self.alloc_map.get_or(id, || Err(())) {
Ok((kind, alloc)) => {
let extra = match kind {
MemoryKind::Stack => " (stack)".to_owned(),
MemoryKind::Vtable => " (vtable)".to_owned(),
MemoryKind::Machine(m) => format!(" ({:?})", m),
};
self.dump_alloc_helper(
&mut allocs_seen, &mut allocs_to_print,
msg, alloc, extra
);
},
Err(()) => {
// static alloc?
match self.tcx.alloc_map.lock().get(id) {
Some(AllocType::Memory(alloc)) => {
self.dump_alloc_helper(
&mut allocs_seen, &mut allocs_to_print,
msg, alloc, " (immutable)".to_owned()
);
}
Some(AllocType::Function(func)) => {
trace!("{} {}", msg, func);
}
Some(AllocType::Static(did)) => {
trace!("{} {:?}", msg, did);
}
None => {
trace!("{} (deallocated)", msg);
}
}
},
};
}
}
pub fn leak_report(&self) -> usize {
trace!("### LEAK REPORT ###");
let leaks: Vec<_> = self.alloc_map.filter_map_collect(|&id, &(kind, _)| {
if kind.may_leak() { None } else { Some(id) }
});
let n = leaks.len();
self.dump_allocs(leaks);
n
}
/// This is used by [priroda](https://github.com/oli-obk/priroda)
pub fn alloc_map_ref(&self) -> &M::MemoryMap {
&self.alloc_map
}
}
/// Byte accessors
impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
/// The last argument controls whether we error out when there are undefined
/// or pointer bytes. You should never call this, call `get_bytes` or
/// `get_bytes_with_undef_and_ptr` instead,
///
/// This function also guarantees that the resulting pointer will remain stable
/// even when new allocations are pushed to the `HashMap`. `copy_repeatedly` relies
/// on that.
fn get_bytes_internal(
&self,
ptr: Pointer<M::PointerTag>,
size: Size,
align: Align,
check_defined_and_ptr: bool,
) -> EvalResult<'tcx, &[u8]> {
assert_ne!(size.bytes(), 0, "0-sized accesses should never even get a `Pointer`");
self.check_align(ptr.into(), align)?;
self.check_bounds(ptr, size, true)?;
if check_defined_and_ptr {
self.check_defined(ptr, size)?;
self.check_relocations(ptr, size)?;
} else {
// We still don't want relocations on the *edges*
self.check_relocation_edges(ptr, size)?;
}
let alloc = self.get(ptr.alloc_id)?;
M::memory_accessed(alloc, ptr, size, MemoryAccess::Read)?;
assert_eq!(ptr.offset.bytes() as usize as u64, ptr.offset.bytes());
assert_eq!(size.bytes() as usize as u64, size.bytes());
let offset = ptr.offset.bytes() as usize;
Ok(&alloc.bytes[offset..offset + size.bytes() as usize])
}
#[inline]
fn get_bytes(
&self,
ptr: Pointer<M::PointerTag>,
size: Size,
align: Align
) -> EvalResult<'tcx, &[u8]> {
self.get_bytes_internal(ptr, size, align, true)
}
/// It is the caller's responsibility to handle undefined and pointer bytes.
/// However, this still checks that there are no relocations on the *egdes*.
#[inline]
fn get_bytes_with_undef_and_ptr(
&self,
ptr: Pointer<M::PointerTag>,
size: Size,
align: Align
) -> EvalResult<'tcx, &[u8]> {
self.get_bytes_internal(ptr, size, align, false)
}
/// Just calling this already marks everything as defined and removes relocations,
/// so be sure to actually put data there!
fn get_bytes_mut(
&mut self,
ptr: Pointer<M::PointerTag>,
size: Size,
align: Align,
) -> EvalResult<'tcx, &mut [u8]> {
assert_ne!(size.bytes(), 0, "0-sized accesses should never even get a `Pointer`");
self.check_align(ptr.into(), align)?;
self.check_bounds(ptr, size, true)?;
self.mark_definedness(ptr, size, true)?;
self.clear_relocations(ptr, size)?;
let alloc = self.get_mut(ptr.alloc_id)?;
M::memory_accessed(alloc, ptr, size, MemoryAccess::Write)?;
assert_eq!(ptr.offset.bytes() as usize as u64, ptr.offset.bytes());
assert_eq!(size.bytes() as usize as u64, size.bytes());
let offset = ptr.offset.bytes() as usize;
Ok(&mut alloc.bytes[offset..offset + size.bytes() as usize])
}
}
/// Interning (for CTFE)
impl<'a, 'mir, 'tcx, M> Memory<'a, 'mir, 'tcx, M>
where
M: Machine<'a, 'mir, 'tcx, PointerTag=(), AllocExtra=()>,
M::MemoryMap: AllocMap<AllocId, (MemoryKind<M::MemoryKinds>, Allocation)>,
{
/// mark an allocation as static and initialized, either mutable or not
pub fn intern_static(
&mut self,
alloc_id: AllocId,
mutability: Mutability,
) -> EvalResult<'tcx> {
trace!(
"mark_static_initialized {:?}, mutability: {:?}",
alloc_id,
mutability
);
// remove allocation
let (kind, mut alloc) = self.alloc_map.remove(&alloc_id).unwrap();
match kind {
MemoryKind::Machine(_) => bug!("Static cannot refer to machine memory"),
MemoryKind::Stack | MemoryKind::Vtable => {},
}
// ensure llvm knows not to put this into immutable memory
alloc.mutability = mutability;
let alloc = self.tcx.intern_const_alloc(alloc);
self.tcx.alloc_map.lock().set_id_memory(alloc_id, alloc);
// recurse into inner allocations
for &(_, alloc) in alloc.relocations.values() {
// FIXME: Reusing the mutability here is likely incorrect. It is originally
// determined via `is_freeze`, and data is considered frozen if there is no
// `UnsafeCell` *immediately* in that data -- however, this search stops
// at references. So whenever we follow a reference, we should likely
// assume immutability -- and we should make sure that the compiler
// does not permit code that would break this!
if self.alloc_map.contains_key(&alloc) {
// Not yet interned, so proceed recursively
self.intern_static(alloc, mutability)?;
}
}
Ok(())
}
}
/// Reading and writing
impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
pub fn copy(
&mut self,
src: Scalar<M::PointerTag>,
src_align: Align,
dest: Scalar<M::PointerTag>,
dest_align: Align,
size: Size,
nonoverlapping: bool,
) -> EvalResult<'tcx> {
self.copy_repeatedly(src, src_align, dest, dest_align, size, 1, nonoverlapping)
}
pub fn copy_repeatedly(
&mut self,
src: Scalar<M::PointerTag>,
src_align: Align,
dest: Scalar<M::PointerTag>,
dest_align: Align,
size: Size,
length: u64,
nonoverlapping: bool,
) -> EvalResult<'tcx> {
if size.bytes() == 0 {
// Nothing to do for ZST, other than checking alignment and non-NULLness.
self.check_align(src, src_align)?;
self.check_align(dest, dest_align)?;
return Ok(());
}
let src = src.to_ptr()?;
let dest = dest.to_ptr()?;
// first copy the relocations to a temporary buffer, because
// `get_bytes_mut` will clear the relocations, which is correct,
// since we don't want to keep any relocations at the target.
// (`get_bytes_with_undef_and_ptr` below checks that there are no
// relocations overlapping the edges; those would not be handled correctly).
let relocations = {
let relocations = self.relocations(src, size)?;
let mut new_relocations = Vec::with_capacity(relocations.len() * (length as usize));
for i in 0..length {
new_relocations.extend(
relocations
.iter()
.map(|&(offset, reloc)| {
(offset + dest.offset - src.offset + (i * size * relocations.len() as u64),
reloc)
})
);
}
new_relocations
};
// This also checks alignment, and relocation edges on the src.
let src_bytes = self.get_bytes_with_undef_and_ptr(src, size, src_align)?.as_ptr();
let dest_bytes = self.get_bytes_mut(dest, size * length, dest_align)?.as_mut_ptr();
// SAFE: The above indexing would have panicked if there weren't at least `size` bytes
// behind `src` and `dest`. Also, we use the overlapping-safe `ptr::copy` if `src` and
// `dest` could possibly overlap.
// The pointers above remain valid even if the `HashMap` table is moved around because they
// point into the `Vec` storing the bytes.
unsafe {
assert_eq!(size.bytes() as usize as u64, size.bytes());
if src.alloc_id == dest.alloc_id {
if nonoverlapping {
if (src.offset <= dest.offset && src.offset + size > dest.offset) ||
(dest.offset <= src.offset && dest.offset + size > src.offset)
{
return err!(Intrinsic(
"copy_nonoverlapping called on overlapping ranges".to_string(),
));
}
}
for i in 0..length {
ptr::copy(src_bytes,
dest_bytes.offset((size.bytes() * i) as isize),
size.bytes() as usize);
}
} else {
for i in 0..length {
ptr::copy_nonoverlapping(src_bytes,
dest_bytes.offset((size.bytes() * i) as isize),
size.bytes() as usize);
}
}
}
// copy definedness to the destination
self.copy_undef_mask(src, dest, size, length)?;
// copy the relocations to the destination
self.get_mut(dest.alloc_id)?.relocations.insert_presorted(relocations);
Ok(())
}
pub fn read_c_str(&self, ptr: Pointer<M::PointerTag>) -> EvalResult<'tcx, &[u8]> {
let alloc = self.get(ptr.alloc_id)?;
assert_eq!(ptr.offset.bytes() as usize as u64, ptr.offset.bytes());
let offset = ptr.offset.bytes() as usize;
match alloc.bytes[offset..].iter().position(|&c| c == 0) {
Some(size) => {
let p1 = Size::from_bytes((size + 1) as u64);
self.check_relocations(ptr, p1)?;
self.check_defined(ptr, p1)?;
Ok(&alloc.bytes[offset..offset + size])
}
None => err!(UnterminatedCString(ptr.erase_tag())),
}
}
pub fn check_bytes(
&self,
ptr: Scalar<M::PointerTag>,
size: Size,
allow_ptr_and_undef: bool,
) -> EvalResult<'tcx> {
// Empty accesses don't need to be valid pointers, but they should still be non-NULL
let align = Align::from_bytes(1, 1).unwrap();
if size.bytes() == 0 {
self.check_align(ptr, align)?;
return Ok(());
}
let ptr = ptr.to_ptr()?;
// Check bounds, align and relocations on the edges
self.get_bytes_with_undef_and_ptr(ptr, size, align)?;
// Check undef and ptr
if !allow_ptr_and_undef {
self.check_defined(ptr, size)?;
self.check_relocations(ptr, size)?;
}
Ok(())
}
pub fn read_bytes(&self, ptr: Scalar<M::PointerTag>, size: Size) -> EvalResult<'tcx, &[u8]> {
// Empty accesses don't need to be valid pointers, but they should still be non-NULL
let align = Align::from_bytes(1, 1).unwrap();
if size.bytes() == 0 {
self.check_align(ptr, align)?;
return Ok(&[]);
}
self.get_bytes(ptr.to_ptr()?, size, align)
}
pub fn write_bytes(&mut self, ptr: Scalar<M::PointerTag>, src: &[u8]) -> EvalResult<'tcx> {
// Empty accesses don't need to be valid pointers, but they should still be non-NULL
let align = Align::from_bytes(1, 1).unwrap();
if src.is_empty() {
self.check_align(ptr, align)?;
return Ok(());
}
let bytes = self.get_bytes_mut(ptr.to_ptr()?, Size::from_bytes(src.len() as u64), align)?;
bytes.clone_from_slice(src);
Ok(())
}
pub fn write_repeat(
&mut self,
ptr: Scalar<M::PointerTag>,
val: u8,
count: Size
) -> EvalResult<'tcx> {
// Empty accesses don't need to be valid pointers, but they should still be non-NULL
let align = Align::from_bytes(1, 1).unwrap();
if count.bytes() == 0 {
self.check_align(ptr, align)?;
return Ok(());
}
let bytes = self.get_bytes_mut(ptr.to_ptr()?, count, align)?;
for b in bytes {
*b = val;
}
Ok(())
}
/// Read a *non-ZST* scalar
pub fn read_scalar(
&self,
ptr: Pointer<M::PointerTag>,
ptr_align: Align,
size: Size
) -> EvalResult<'tcx, ScalarMaybeUndef<M::PointerTag>> {
// get_bytes_unchecked tests alignment and relocation edges
let bytes = self.get_bytes_with_undef_and_ptr(
ptr, size, ptr_align.min(self.int_align(size))
)?;
// Undef check happens *after* we established that the alignment is correct.
// We must not return Ok() for unaligned pointers!
if self.check_defined(ptr, size).is_err() {
// this inflates undefined bytes to the entire scalar, even if only a few
// bytes are undefined
return Ok(ScalarMaybeUndef::Undef);
}
// Now we do the actual reading
let bits = read_target_uint(self.tcx.data_layout.endian, bytes).unwrap();
// See if we got a pointer
if size != self.pointer_size() {
// *Now* better make sure that the inside also is free of relocations.
self.check_relocations(ptr, size)?;
} else {
let alloc = self.get(ptr.alloc_id)?;
match alloc.relocations.get(&ptr.offset) {
Some(&(tag, alloc_id)) => {
let ptr = Pointer::new_with_tag(alloc_id, Size::from_bytes(bits as u64), tag);
return Ok(ScalarMaybeUndef::Scalar(ptr.into()))
}
None => {},
}
}
// We don't. Just return the bits.
Ok(ScalarMaybeUndef::Scalar(Scalar::from_uint(bits, size)))
}
pub fn read_ptr_sized(
&self,
ptr: Pointer<M::PointerTag>,
ptr_align: Align
) -> EvalResult<'tcx, ScalarMaybeUndef<M::PointerTag>> {
self.read_scalar(ptr, ptr_align, self.pointer_size())
}
/// Write a *non-ZST* scalar
pub fn write_scalar(
&mut self,
ptr: Pointer<M::PointerTag>,
ptr_align: Align,
val: ScalarMaybeUndef<M::PointerTag>,
type_size: Size,
) -> EvalResult<'tcx> {
let val = match val {
ScalarMaybeUndef::Scalar(scalar) => scalar,
ScalarMaybeUndef::Undef => return self.mark_definedness(ptr, type_size, false),
};
let bytes = match val {
Scalar::Ptr(val) => {
assert_eq!(type_size, self.pointer_size());
val.offset.bytes() as u128
}
Scalar::Bits { bits, size } => {
assert_eq!(size as u64, type_size.bytes());
debug_assert_eq!(truncate(bits, Size::from_bytes(size.into())), bits,
"Unexpected value of size {} when writing to memory", size);
bits
},
};
{
// get_bytes_mut checks alignment
let endian = self.tcx.data_layout.endian;
let dst = self.get_bytes_mut(ptr, type_size, ptr_align)?;
write_target_uint(endian, dst, bytes).unwrap();
}
// See if we have to also write a relocation
match val {