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Rollup merge of #70241 - RalfJung:global-mem, r=oli-obk

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Miri: move ModifiedStatic to ConstEval errors

Also generally adjust terminology from "static" to "global" where appropriate (to avoid confusion with specifically `static` items).
This commit is contained in:
Mazdak Farrokhzad 2020-03-24 21:32:29 +01:00 committed by GitHub
commit b8093bad58
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GPG Key ID: 4AEE18F83AFDEB23
17 changed files with 179 additions and 111 deletions
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9
src/librustc/mir/interpret/error.rs
View File

@ -453,9 +453,6 @@ pub enum UnsupportedOpInfo {
ReadForeignStatic(DefId),
/// Could not find MIR for a function.
NoMirFor(DefId),
/// Modified a static during const-eval.
/// FIXME: move this to `ConstEvalErrKind` through a machine hook.
ModifiedStatic,
/// Encountered a pointer where we needed raw bytes.
ReadPointerAsBytes,
/// Encountered raw bytes where we needed a pointer.
@ -471,12 +468,6 @@ impl fmt::Debug for UnsupportedOpInfo {
write!(f, "tried to read from foreign (extern) static {:?}", did)
}
NoMirFor(did) => write!(f, "could not load MIR for {:?}", did),
ModifiedStatic => write!(
f,
"tried to modify a static's initial value from another static's \
initializer"
),
ReadPointerAsBytes => write!(f, "unable to turn pointer into raw bytes",),
ReadBytesAsPointer => write!(f, "unable to turn bytes into a pointer"),
}

1
src/librustc/ty/context.rs
View File

@ -984,6 +984,7 @@ pub struct GlobalCtxt<'tcx> {
/// Stores the value of constants (and deduplicates the actual memory)
allocation_interner: ShardedHashMap<&'tcx Allocation, ()>,
/// Stores memory for globals (statics/consts).
pub alloc_map: Lock<interpret::AllocMap<'tcx>>,
layout_interner: ShardedHashMap<&'tcx LayoutDetails, ()>,

4
src/librustc_mir/const_eval/error.rs
View File

@ -12,6 +12,7 @@ use crate::interpret::{ConstEvalErr, InterpErrorInfo, Machine};
pub enum ConstEvalErrKind {
NeedsRfc(String),
ConstAccessesStatic,
ModifiedGlobal,
AssertFailure(AssertKind<u64>),
Panic { msg: Symbol, line: u32, col: u32, file: Symbol },
}
@ -33,6 +34,9 @@ impl fmt::Display for ConstEvalErrKind {
write!(f, "\"{}\" needs an rfc before being allowed inside constants", msg)
}
ConstAccessesStatic => write!(f, "constant accesses static"),
ModifiedGlobal => {
write!(f, "modifying a static's initial value from another static's initializer")
}
AssertFailure(ref msg) => write!(f, "{:?}", msg),
Panic { msg, line, col, file } => {
write!(f, "the evaluated program panicked at '{}', {}:{}:{}", msg, file, line, col)

23
src/librustc_mir/const_eval/machine.rs
View File

@ -8,8 +8,9 @@ use std::hash::Hash;
use rustc_data_structures::fx::FxHashMap;
use rustc::mir::AssertMessage;
use rustc_span::source_map::Span;
use rustc_ast::ast::Mutability;
use rustc_span::symbol::Symbol;
use rustc_span::{def_id::DefId, Span};
use crate::interpret::{
self, AllocId, Allocation, GlobalId, ImmTy, InterpCx, InterpResult, Memory, MemoryKind, OpTy,
@ -167,7 +168,7 @@ impl interpret::MayLeak for ! {
}
impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter {
type MemoryKinds = !;
type MemoryKind = !;
type PointerTag = ();
type ExtraFnVal = !;
@ -177,7 +178,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter {
type MemoryMap = FxHashMap<AllocId, (MemoryKind<!>, Allocation)>;
const STATIC_KIND: Option<!> = None; // no copying of statics allowed
const GLOBAL_KIND: Option<!> = None; // no copying of globals allowed
// We do not check for alignment to avoid having to carry an `Align`
// in `ConstValue::ByRef`.
@ -317,7 +318,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter {
}
#[inline(always)]
fn tag_static_base_pointer(_memory_extra: &MemoryExtra, _id: AllocId) -> Self::PointerTag {}
fn tag_global_base_pointer(_memory_extra: &MemoryExtra, _id: AllocId) -> Self::PointerTag {}
fn box_alloc(
_ecx: &mut InterpCx<'mir, 'tcx, Self>,
@ -345,11 +346,19 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter {
Ok(())
}
fn before_access_static(
fn before_access_global(
memory_extra: &MemoryExtra,
_allocation: &Allocation,
alloc_id: AllocId,
allocation: &Allocation,
def_id: Option<DefId>,
is_write: bool,
) -> InterpResult<'tcx> {
if memory_extra.can_access_statics {
if is_write && allocation.mutability == Mutability::Not {
Err(err_ub!(WriteToReadOnly(alloc_id)).into())
} else if is_write {
Err(ConstEvalErrKind::ModifiedGlobal.into())
} else if memory_extra.can_access_statics || def_id.is_none() {
// `def_id.is_none()` indicates this is not a static, but a const or so.
Ok(())
} else {
Err(ConstEvalErrKind::ConstAccessesStatic.into())

4
src/librustc_mir/interpret/eval_context.rs
View File

@ -253,8 +253,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
/// This represents a *direct* access to that memory, as opposed to access
/// through a pointer that was created by the program.
#[inline(always)]
pub fn tag_static_base_pointer(&self, ptr: Pointer) -> Pointer<M::PointerTag> {
self.memory.tag_static_base_pointer(ptr)
pub fn tag_global_base_pointer(&self, ptr: Pointer) -> Pointer<M::PointerTag> {
self.memory.tag_global_base_pointer(ptr)
}
#[inline(always)]

4
src/librustc_mir/interpret/intern.rs
View File

@ -16,7 +16,7 @@ use super::{AllocId, Allocation, InterpCx, MPlaceTy, Machine, MemoryKind, Scalar
pub trait CompileTimeMachine<'mir, 'tcx> = Machine<
'mir,
'tcx,
MemoryKinds = !,
MemoryKind = !,
PointerTag = (),
ExtraFnVal = !,
FrameExtra = (),
@ -104,7 +104,7 @@ fn intern_shallow<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx>>(
MemoryKind::Stack | MemoryKind::Vtable | MemoryKind::CallerLocation => {}
}
// Set allocation mutability as appropriate. This is used by LLVM to put things into
// read-only memory, and also by Miri when evluating other constants/statics that
// read-only memory, and also by Miri when evaluating other globals that
// access this one.
if mode == InternMode::Static {
// When `ty` is `None`, we assume no interior mutability.

37
src/librustc_mir/interpret/machine.rs
View File

@ -7,7 +7,7 @@ use std::hash::Hash;
use rustc::mir;
use rustc::ty::{self, Ty};
use rustc_span::Span;
use rustc_span::{def_id::DefId, Span};
use super::{
AllocId, Allocation, AllocationExtra, Frame, ImmTy, InterpCx, InterpResult, Memory, MemoryKind,
@ -79,7 +79,7 @@ pub trait AllocMap<K: Hash + Eq, V> {
/// and some use case dependent behaviour can instead be applied.
pub trait Machine<'mir, 'tcx>: Sized {
/// Additional memory kinds a machine wishes to distinguish from the builtin ones
type MemoryKinds: ::std::fmt::Debug + MayLeak + Eq + 'static;
type MemoryKind: ::std::fmt::Debug + MayLeak + Eq + 'static;
/// Tag tracked alongside every pointer. This is used to implement "Stacked Borrows"
/// <https://www.ralfj.de/blog/2018/08/07/stacked-borrows.html>.
@ -105,16 +105,17 @@ pub trait Machine<'mir, 'tcx>: Sized {
/// Memory's allocation map
type MemoryMap: AllocMap<
AllocId,
(MemoryKind<Self::MemoryKinds>, Allocation<Self::PointerTag, Self::AllocExtra>),
(MemoryKind<Self::MemoryKind>, Allocation<Self::PointerTag, Self::AllocExtra>),
> + Default
+ Clone;
/// The memory kind to use for copied statics -- or None if statics should not be mutated
/// and thus any such attempt will cause a `ModifiedStatic` error to be raised.
/// The memory kind to use for copied global memory (held in `tcx`) --
/// or None if such memory should not be mutated and thus any such attempt will cause
/// a `ModifiedStatic` error to be raised.
/// Statics are copied under two circumstances: When they are mutated, and when
/// `tag_allocation` or `find_foreign_static` (see below) returns an owned allocation
/// `tag_allocation` (see below) returns an owned allocation
/// that is added to the memory so that the work is not done twice.
const STATIC_KIND: Option<Self::MemoryKinds>;
const GLOBAL_KIND: Option<Self::MemoryKind>;
/// Whether memory accesses should be alignment-checked.
const CHECK_ALIGN: bool;
@ -207,11 +208,15 @@ pub trait Machine<'mir, 'tcx>: Sized {
Ok(())
}
/// Called before a `Static` value is accessed.
/// Called before a global allocation is accessed.
/// `def_id` is `Some` if this is the "lazy" allocation of a static.
#[inline]
fn before_access_static(
fn before_access_global(
_memory_extra: &Self::MemoryExtra,
_alloc_id: AllocId,
_allocation: &Allocation,
_def_id: Option<DefId>,
_is_write: bool,
) -> InterpResult<'tcx> {
Ok(())
}
@ -231,10 +236,10 @@ pub trait Machine<'mir, 'tcx>: Sized {
/// it contains (in relocations) tagged. The way we construct allocations is
/// to always first construct it without extra and then add the extra.
/// This keeps uniform code paths for handling both allocations created by CTFE
/// for statics, and allocations created by Miri during evaluation.
/// for globals, and allocations created by Miri during evaluation.
///
/// `kind` is the kind of the allocation being tagged; it can be `None` when
/// it's a static and `STATIC_KIND` is `None`.
/// it's a global and `GLOBAL_KIND` is `None`.
///
/// This should avoid copying if no work has to be done! If this returns an owned
/// allocation (because a copy had to be done to add tags or metadata), machine memory will
@ -243,20 +248,20 @@ pub trait Machine<'mir, 'tcx>: Sized {
///
/// Also return the "base" tag to use for this allocation: the one that is used for direct
/// accesses to this allocation. If `kind == STATIC_KIND`, this tag must be consistent
/// with `tag_static_base_pointer`.
/// with `tag_global_base_pointer`.
fn init_allocation_extra<'b>(
memory_extra: &Self::MemoryExtra,
id: AllocId,
alloc: Cow<'b, Allocation>,
kind: Option<MemoryKind<Self::MemoryKinds>>,
kind: Option<MemoryKind<Self::MemoryKind>>,
) -> (Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>, Self::PointerTag);
/// Return the "base" tag for the given *static* allocation: the one that is used for direct
/// accesses to this static/const/fn allocation. If `id` is not a static allocation,
/// Return the "base" tag for the given *global* allocation: the one that is used for direct
/// accesses to this static/const/fn allocation. If `id` is not a global allocation,
/// this will return an unusable tag (i.e., accesses will be UB)!
///
/// Expects `id` to be already canonical, if needed.
fn tag_static_base_pointer(memory_extra: &Self::MemoryExtra, id: AllocId) -> Self::PointerTag;
fn tag_global_base_pointer(memory_extra: &Self::MemoryExtra, id: AllocId) -> Self::PointerTag;
/// Executes a retagging operation
#[inline]

113
src/librustc_mir/interpret/memory.rs
View File

@ -80,12 +80,12 @@ pub struct Memory<'mir, 'tcx, M: Machine<'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
/// global 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 global (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.
/// Either way, if the machine allows writing to a global, doing so will
/// create a copy of the global allocation here.
// FIXME: this should not be public, but interning currently needs access to it
pub(super) alloc_map: M::MemoryMap,
@ -130,9 +130,9 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
/// This represents a *direct* access to that memory, as opposed to access
/// through a pointer that was created by the program.
#[inline]
pub fn tag_static_base_pointer(&self, ptr: Pointer) -> Pointer<M::PointerTag> {
pub fn tag_global_base_pointer(&self, ptr: Pointer) -> Pointer<M::PointerTag> {
let id = M::canonical_alloc_id(self, ptr.alloc_id);
ptr.with_tag(M::tag_static_base_pointer(&self.extra, id))
ptr.with_tag(M::tag_global_base_pointer(&self.extra, id))
}
pub fn create_fn_alloc(
@ -149,23 +149,23 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
id
}
};
self.tag_static_base_pointer(Pointer::from(id))
self.tag_global_base_pointer(Pointer::from(id))
}
pub fn allocate(
&mut self,
size: Size,
align: Align,
kind: MemoryKind<M::MemoryKinds>,
kind: MemoryKind<M::MemoryKind>,
) -> Pointer<M::PointerTag> {
let alloc = Allocation::undef(size, align);
self.allocate_with(alloc, kind)
}
pub fn allocate_static_bytes(
pub fn allocate_bytes(
&mut self,
bytes: &[u8],
kind: MemoryKind<M::MemoryKinds>,
kind: MemoryKind<M::MemoryKind>,
) -> Pointer<M::PointerTag> {
let alloc = Allocation::from_byte_aligned_bytes(bytes);
self.allocate_with(alloc, kind)
@ -174,13 +174,13 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
pub fn allocate_with(
&mut self,
alloc: Allocation,
kind: MemoryKind<M::MemoryKinds>,
kind: MemoryKind<M::MemoryKind>,
) -> Pointer<M::PointerTag> {
let id = self.tcx.alloc_map.lock().reserve();
debug_assert_ne!(
Some(kind),
M::STATIC_KIND.map(MemoryKind::Machine),
"dynamically allocating static memory"
M::GLOBAL_KIND.map(MemoryKind::Machine),
"dynamically allocating global memory"
);
let (alloc, tag) = M::init_allocation_extra(&self.extra, id, Cow::Owned(alloc), Some(kind));
self.alloc_map.insert(id, (kind, alloc.into_owned()));
@ -193,7 +193,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
old_size_and_align: Option<(Size, Align)>,
new_size: Size,
new_align: Align,
kind: MemoryKind<M::MemoryKinds>,
kind: MemoryKind<M::MemoryKind>,
) -> InterpResult<'tcx, Pointer<M::PointerTag>> {
if ptr.offset.bytes() != 0 {
throw_ub_format!(
@ -215,9 +215,9 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
Ok(new_ptr)
}
/// Deallocate a local, or do nothing if that local has been made into a static
/// Deallocate a local, or do nothing if that local has been made into a global.
pub fn deallocate_local(&mut self, ptr: Pointer<M::PointerTag>) -> InterpResult<'tcx> {
// The allocation might be already removed by static interning.
// The allocation might be already removed by global 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)
@ -230,7 +230,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
&mut self,
ptr: Pointer<M::PointerTag>,
old_size_and_align: Option<(Size, Align)>,
kind: MemoryKind<M::MemoryKinds>,
kind: MemoryKind<M::MemoryKind>,
) -> InterpResult<'tcx> {
trace!("deallocating: {}", ptr.alloc_id);
@ -244,7 +244,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
let (alloc_kind, mut alloc) = match self.alloc_map.remove(&ptr.alloc_id) {
Some(alloc) => alloc,
None => {
// Deallocating static memory -- always an error
// Deallocating global memory -- always an error
return Err(match self.tcx.alloc_map.lock().get(ptr.alloc_id) {
Some(GlobalAlloc::Function(..)) => err_ub_format!("deallocating a function"),
Some(GlobalAlloc::Static(..)) | Some(GlobalAlloc::Memory(..)) => {
@ -403,43 +403,45 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
/// Allocation accessors
impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
/// Helper function to obtain the global (tcx) allocation for a static.
/// Helper function to obtain a global (tcx) allocation.
/// 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::tag_allocation`.
///
/// Notice that every static has two `AllocId` that will resolve to the same
/// thing here: one maps to `GlobalAlloc::Static`, this is the "lazy" ID,
/// and the other one is maps to `GlobalAlloc::Memory`, this is returned by
/// `const_eval_raw` and it is the "resolved" ID.
/// The resolved ID is never used by the interpreted progrma, it is hidden.
/// The `GlobalAlloc::Memory` branch here is still reachable though; when a static
/// contains a reference to memory that was created during its evaluation (i.e., not to
/// another static), those inner references only exist in "resolved" form.
///
/// Assumes `id` is already canonical.
fn get_static_alloc(
fn get_global_alloc(
memory_extra: &M::MemoryExtra,
tcx: TyCtxtAt<'tcx>,
id: AllocId,
is_write: bool,
) -> InterpResult<'tcx, Cow<'tcx, Allocation<M::PointerTag, M::AllocExtra>>> {
let alloc = tcx.alloc_map.lock().get(id);
let alloc = match alloc {
Some(GlobalAlloc::Memory(mem)) => Cow::Borrowed(mem),
let (alloc, def_id) = match alloc {
Some(GlobalAlloc::Memory(mem)) => {
// Memory of a constant or promoted or anonymous memory referenced by a static.
(mem, None)
}
Some(GlobalAlloc::Function(..)) => throw_ub!(DerefFunctionPointer(id)),
None => throw_ub!(PointerUseAfterFree(id)),
Some(GlobalAlloc::Static(def_id)) => {
// We got a "lazy" static that has not been computed yet.
// Notice that every static has two `AllocId` that will resolve to the same
// thing here: one maps to `GlobalAlloc::Static`, this is the "lazy" ID,
// and the other one is maps to `GlobalAlloc::Memory`, this is returned by
// `const_eval_raw` and it is the "resolved" ID.
// The resolved ID is never used by the interpreted progrma, it is hidden.
// The `GlobalAlloc::Memory` branch here is still reachable though; when a static
// contains a reference to memory that was created during its evaluation (i.e., not
// to another static), those inner references only exist in "resolved" form.
//
// Assumes `id` is already canonical.
if tcx.is_foreign_item(def_id) {
trace!("get_static_alloc: foreign item {:?}", def_id);
trace!("get_global_alloc: foreign item {:?}", def_id);
throw_unsup!(ReadForeignStatic(def_id))
}
trace!("get_static_alloc: Need to compute {:?}", def_id);
trace!("get_global_alloc: Need to compute {:?}", def_id);
let instance = Instance::mono(tcx.tcx, def_id);
let gid = GlobalId { instance, promoted: None };
// use the raw query here to break validation cycles. Later uses of the static
// will call the full query anyway
// Use the raw query here to break validation cycles. Later uses of the static
// will call the full query anyway.
let raw_const =
tcx.const_eval_raw(ty::ParamEnv::reveal_all().and(gid)).map_err(|err| {
// no need to report anything, the const_eval call takes care of that
@ -454,18 +456,19 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
let id = raw_const.alloc_id;
let allocation = tcx.alloc_map.lock().unwrap_memory(id);
M::before_access_static(memory_extra, allocation)?;
Cow::Borrowed(allocation)
(allocation, Some(def_id))
}
};
M::before_access_global(memory_extra, id, alloc, def_id, is_write)?;
let alloc = Cow::Borrowed(alloc);
// We got tcx memory. Let the machine initialize its "extra" stuff.
let (alloc, tag) = M::init_allocation_extra(
memory_extra,
id, // always use the ID we got as input, not the "hidden" one.
alloc,
M::STATIC_KIND.map(MemoryKind::Machine),
M::GLOBAL_KIND.map(MemoryKind::Machine),
);
debug_assert_eq!(tag, M::tag_static_base_pointer(memory_extra, id));
debug_assert_eq!(tag, M::tag_global_base_pointer(memory_extra, id));
Ok(alloc)
}
@ -478,10 +481,11 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
let id = M::canonical_alloc_id(self, id);
// 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.
// `get_global_alloc` that we can actually use directly without inserting anything anywhere.
// So the error type is `InterpResult<'tcx, &Allocation<M::PointerTag>>`.
let a = self.alloc_map.get_or(id, || {
let alloc = Self::get_static_alloc(&self.extra, self.tcx, id).map_err(Err)?;
let alloc = Self::get_global_alloc(&self.extra, self.tcx, id, /*is_write*/ false)
.map_err(Err)?;
match alloc {
Cow::Borrowed(alloc) => {
// We got a ref, cheaply return that as an "error" so that the
@ -490,8 +494,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
}
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 \
let kind = M::GLOBAL_KIND.expect(
"I got a global allocation that I have to copy but the machine does \
not expect that to happen",
);
Ok((MemoryKind::Machine(kind), alloc))
@ -515,16 +519,17 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
let tcx = self.tcx;
let memory_extra = &self.extra;
let a = self.alloc_map.get_mut_or(id, || {
// Need to make a copy, even if `get_static_alloc` is able
// Need to make a copy, even if `get_global_alloc` is able
// to give us a cheap reference.
let alloc = Self::get_static_alloc(memory_extra, tcx, id)?;
let alloc = Self::get_global_alloc(memory_extra, tcx, id, /*is_write*/ true)?;
if alloc.mutability == Mutability::Not {
throw_ub!(WriteToReadOnly(id))
}
match M::STATIC_KIND {
Some(kind) => Ok((MemoryKind::Machine(kind), alloc.into_owned())),
None => throw_unsup!(ModifiedStatic),
}
let kind = M::GLOBAL_KIND.expect(
"I got a global allocation that I have to copy 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`)
@ -553,7 +558,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
// # Regular allocations
// Don't use `self.get_raw` here as that will
// a) cause cycles in case `id` refers to a static
// b) duplicate a static's allocation in miri
// b) duplicate a global's allocation in miri
if let Some((_, alloc)) = self.alloc_map.get(id) {
return Ok((alloc.size, alloc.align));
}
@ -728,7 +733,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
);
}
Err(()) => {
// static alloc?
// global alloc?
match self.tcx.alloc_map.lock().get(id) {
Some(GlobalAlloc::Memory(alloc)) => {
self.dump_alloc_helper(

6
src/librustc_mir/interpret/operand.rs
View File

@ -517,7 +517,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
layout: Option<TyLayout<'tcx>>,
) -> InterpResult<'tcx, OpTy<'tcx, M::PointerTag>> {
let tag_scalar = |scalar| match scalar {
Scalar::Ptr(ptr) => Scalar::Ptr(self.tag_static_base_pointer(ptr)),
Scalar::Ptr(ptr) => Scalar::Ptr(self.tag_global_base_pointer(ptr)),
Scalar::Raw { data, size } => Scalar::Raw { data, size },
};
// Early-return cases.
@ -547,7 +547,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
let id = self.tcx.alloc_map.lock().create_memory_alloc(alloc);
// We rely on mutability being set correctly in that allocation to prevent writes
// where none should happen.
let ptr = self.tag_static_base_pointer(Pointer::new(id, offset));
let ptr = self.tag_global_base_pointer(Pointer::new(id, offset));
Operand::Indirect(MemPlace::from_ptr(ptr, layout.align.abi))
}
ConstValue::Scalar(x) => Operand::Immediate(tag_scalar(x).into()),
@ -559,7 +559,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
Size::from_bytes(start as u64), // offset: `start`
);
Operand::Immediate(Immediate::new_slice(
self.tag_static_base_pointer(ptr).into(),
self.tag_global_base_pointer(ptr).into(),
(end - start) as u64, // len: `end - start`
self,
))

10
src/librustc_mir/interpret/place.rs
View File

@ -290,7 +290,7 @@ where
Tag: ::std::fmt::Debug + Copy + Eq + Hash + 'static,
M: Machine<'mir, 'tcx, PointerTag = Tag>,
// FIXME: Working around https://github.com/rust-lang/rust/issues/24159
M::MemoryMap: AllocMap<AllocId, (MemoryKind<M::MemoryKinds>, Allocation<Tag, M::AllocExtra>)>,
M::MemoryMap: AllocMap<AllocId, (MemoryKind<M::MemoryKind>, Allocation<Tag, M::AllocExtra>)>,
M::AllocExtra: AllocationExtra<Tag>,
{
/// Take a value, which represents a (thin or wide) reference, and make it a place.
@ -1015,7 +1015,7 @@ where
pub fn allocate(
&mut self,
layout: TyLayout<'tcx>,
kind: MemoryKind<M::MemoryKinds>,
kind: MemoryKind<M::MemoryKind>,
) -> MPlaceTy<'tcx, M::PointerTag> {
let ptr = self.memory.allocate(layout.size, layout.align.abi, kind);
MPlaceTy::from_aligned_ptr(ptr, layout)
@ -1025,9 +1025,9 @@ where
pub fn allocate_str(
&mut self,
str: &str,
kind: MemoryKind<M::MemoryKinds>,
kind: MemoryKind<M::MemoryKind>,
) -> MPlaceTy<'tcx, M::PointerTag> {
let ptr = self.memory.allocate_static_bytes(str.as_bytes(), kind);
let ptr = self.memory.allocate_bytes(str.as_bytes(), kind);
let meta = Scalar::from_uint(str.len() as u128, self.pointer_size());
let mplace = MemPlace {
ptr: ptr.into(),
@ -1118,7 +1118,7 @@ where
) -> InterpResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
// This must be an allocation in `tcx`
assert!(self.tcx.alloc_map.lock().get(raw.alloc_id).is_some());
let ptr = self.tag_static_base_pointer(Pointer::from(raw.alloc_id));
let ptr = self.tag_global_base_pointer(Pointer::from(raw.alloc_id));
let layout = self.layout_of(raw.ty)?;
Ok(MPlaceTy::from_aligned_ptr(ptr, layout))
}

27
src/librustc_mir/transform/const_prop.rs
View File

@ -25,7 +25,7 @@ use rustc_hir::def::DefKind;
use rustc_hir::HirId;
use rustc_index::vec::IndexVec;
use rustc_session::lint;
use rustc_span::Span;
use rustc_span::{def_id::DefId, Span};
use rustc_trait_selection::traits;
use crate::const_eval::error_to_const_error;
@ -162,7 +162,7 @@ impl<'tcx> MirPass<'tcx> for ConstProp {
struct ConstPropMachine;
impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine {
type MemoryKinds = !;
type MemoryKind = !;
type PointerTag = ();
type ExtraFnVal = !;
@ -172,7 +172,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine {
type MemoryMap = FxHashMap<AllocId, (MemoryKind<!>, Allocation)>;
const STATIC_KIND: Option<!> = None;
const GLOBAL_KIND: Option<!> = None;
const CHECK_ALIGN: bool = false;
@ -247,7 +247,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine {
}
#[inline(always)]
fn tag_static_base_pointer(_memory_extra: &(), _id: AllocId) -> Self::PointerTag {}
fn tag_global_base_pointer(_memory_extra: &(), _id: AllocId) -> Self::PointerTag {}
fn box_alloc(
_ecx: &mut InterpCx<'mir, 'tcx, Self>,
@ -270,14 +270,23 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine {
l.access()
}
fn before_access_static(
fn before_access_global(
_memory_extra: &(),
_alloc_id: AllocId,
allocation: &Allocation<Self::PointerTag, Self::AllocExtra>,
def_id: Option<DefId>,
is_write: bool,
) -> InterpResult<'tcx> {
// if the static allocation is mutable or if it has relocations (it may be legal to mutate
// the memory behind that in the future), then we can't const prop it
if allocation.mutability == Mutability::Mut || allocation.relocations().len() > 0 {
throw_machine_stop_str!("can't eval mutable statics in ConstProp")
if is_write {
throw_machine_stop_str!("can't write to global");
}
// If the static allocation is mutable or if it has relocations (it may be legal to mutate
// the memory behind that in the future), then we can't const prop it.
if allocation.mutability == Mutability::Mut {
throw_machine_stop_str!("can't eval mutable globals in ConstProp");
}
if def_id.is_some() && allocation.relocations().len() > 0 {
throw_machine_stop_str!("can't eval statics with pointers in ConstProp");
}
Ok(())

2
src/test/ui/consts/const-eval/assign-to-static-within-other-static.stderr
View File

@ -2,7 +2,7 @@ error[E0080]: could not evaluate static initializer
--> $DIR/assign-to-static-within-other-static.rs:10:5
|
LL | FOO = 5;
| ^^^^^^^ tried to modify a static's initial value from another static's initializer
| ^^^^^^^ modifying a static's initial value from another static's initializer
error: aborting due to previous error

15
src/test/ui/consts/miri_unleashed/mutating_global.rs Normal file
View File

@ -0,0 +1,15 @@
// compile-flags: -Zunleash-the-miri-inside-of-you
// Make sure we cannot mutate globals.
static mut GLOBAL: i32 = 0;
const MUTATING_GLOBAL: () = {
unsafe {
GLOBAL = 99 //~ ERROR any use of this value will cause an error
//~^ WARN skipping const checks
//~| WARN skipping const checks
}
};
fn main() {}

29
src/test/ui/consts/miri_unleashed/mutating_global.stderr Normal file
View File

@ -0,0 +1,29 @@
warning: skipping const checks
--> $DIR/mutating_global.rs:9:9
|
LL | GLOBAL = 99
| ^^^^^^
warning: skipping const checks
--> $DIR/mutating_global.rs:9:9
|
LL | GLOBAL = 99
| ^^^^^^
error: any use of this value will cause an error
--> $DIR/mutating_global.rs:9:9
|
LL | / const MUTATING_GLOBAL: () = {
LL | | unsafe {
LL | | GLOBAL = 99
| | ^^^^^^^^^^^ modifying a static's initial value from another static's initializer
LL | |
LL | |
LL | | }
LL | | };
| |__-
|
= note: `#[deny(const_err)]` on by default
error: aborting due to previous error

2
src/test/ui/consts/static_mut_containing_mut_ref2.mut_refs.stderr
View File

@ -2,7 +2,7 @@ error[E0080]: could not evaluate static initializer
--> $DIR/static_mut_containing_mut_ref2.rs:7:45
|
LL | pub static mut STDERR_BUFFER: () = unsafe { *(&mut STDERR_BUFFER_SPACE) = 42; };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ tried to modify a static's initial value from another static's initializer
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ modifying a static's initial value from another static's initializer
error: aborting due to previous error

2
src/test/ui/consts/static_mut_containing_mut_ref3.stderr
View File

@ -2,7 +2,7 @@ error[E0080]: could not evaluate static initializer
--> $DIR/static_mut_containing_mut_ref3.rs:3:31
|
LL | static mut BAR: () = unsafe { FOO.0 = 99; };
| ^^^^^^^^^^ tried to modify a static's initial value from another static's initializer
| ^^^^^^^^^^ modifying a static's initial value from another static's initializer
error: aborting due to previous error

2
src/test/ui/write-to-static-mut-in-static.stderr
View File

@ -2,7 +2,7 @@ error[E0080]: could not evaluate static initializer
--> $DIR/write-to-static-mut-in-static.rs:2:33
|
LL | pub static mut B: () = unsafe { A = 1; };
| ^^^^^ tried to modify a static's initial value from another static's initializer
| ^^^^^ modifying a static's initial value from another static's initializer
error[E0391]: cycle detected when const-evaluating `C`
--> $DIR/write-to-static-mut-in-static.rs:5:34