From 73b38c661d9bc0466547af16d20089e5383f754b Mon Sep 17 00:00:00 2001 From: Oli Scherer Date: Thu, 12 Oct 2023 11:27:43 +0000 Subject: [PATCH] Do not allocate a second "background" alloc id for the main allocation of a static. Instead we re-use the static's alloc id within the interpreter for its initializer to refer to the `Allocation` that only exists within the interpreter. --- compiler/rustc_const_eval/messages.ftl | 2 + .../rustc_const_eval/src/const_eval/error.rs | 4 +- .../src/const_eval/eval_queries.rs | 62 ++++++++++--------- .../src/const_eval/machine.rs | 15 +++++ .../src/interpret/eval_context.rs | 14 ++++- .../rustc_const_eval/src/interpret/intern.rs | 32 ++++++++-- .../rustc_const_eval/src/interpret/machine.rs | 15 +++++ .../rustc_const_eval/src/interpret/memory.rs | 24 +++++-- .../rustc_const_eval/src/interpret/mod.rs | 1 + .../rustc_const_eval/src/interpret/place.rs | 28 ++++++++- .../rustc_const_eval/src/interpret/util.rs | 28 ++++++++- .../src/interpret/validity.rs | 19 +++--- .../recursive-zst-static.default.stderr | 26 ++++++-- tests/ui/consts/recursive-zst-static.rs | 6 +- .../recursive-zst-static.unleash.stderr | 26 ++++++-- .../consts/write-to-static-mut-in-static.rs | 2 +- .../write-to-static-mut-in-static.stderr | 25 ++------ .../recursion/recursive-static-definition.rs | 10 ++- .../recursive-static-definition.stderr | 25 +++----- 19 files changed, 262 insertions(+), 102 deletions(-) diff --git a/compiler/rustc_const_eval/messages.ftl b/compiler/rustc_const_eval/messages.ftl index 85ebbb00c5f..4a6d4fe930c 100644 --- a/compiler/rustc_const_eval/messages.ftl +++ b/compiler/rustc_const_eval/messages.ftl @@ -313,6 +313,8 @@ const_eval_realloc_or_alloc_with_offset = *[other] {""} } {$ptr} which does not point to the beginning of an object +const_eval_recursive_static = encountered static that tried to initialize itself with itself + const_eval_remainder_by_zero = calculating the remainder with a divisor of zero const_eval_remainder_overflow = diff --git a/compiler/rustc_const_eval/src/const_eval/error.rs b/compiler/rustc_const_eval/src/const_eval/error.rs index 80d02589900..935329f1189 100644 --- a/compiler/rustc_const_eval/src/const_eval/error.rs +++ b/compiler/rustc_const_eval/src/const_eval/error.rs @@ -19,6 +19,7 @@ use crate::interpret::{ErrorHandled, InterpError, InterpErrorInfo, MachineStopTy pub enum ConstEvalErrKind { ConstAccessesMutGlobal, ModifiedGlobal, + RecursiveStatic, AssertFailure(AssertKind), Panic { msg: Symbol, line: u32, col: u32, file: Symbol }, } @@ -31,13 +32,14 @@ impl MachineStopType for ConstEvalErrKind { ConstAccessesMutGlobal => const_eval_const_accesses_mut_global, ModifiedGlobal => const_eval_modified_global, Panic { .. } => const_eval_panic, + RecursiveStatic => const_eval_recursive_static, AssertFailure(x) => x.diagnostic_message(), } } fn add_args(self: Box, adder: &mut dyn FnMut(DiagnosticArgName, DiagnosticArgValue)) { use ConstEvalErrKind::*; match *self { - ConstAccessesMutGlobal | ModifiedGlobal => {} + RecursiveStatic | ConstAccessesMutGlobal | ModifiedGlobal => {} AssertFailure(kind) => kind.add_args(adder), Panic { msg, line, col, file } => { adder("msg".into(), msg.into_diagnostic_arg()); diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs index 05baf102d88..7099cdd5a75 100644 --- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs +++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs @@ -2,7 +2,6 @@ use either::{Left, Right}; use rustc_hir::def::DefKind; use rustc_middle::mir::interpret::{AllocId, ErrorHandled, InterpErrorInfo}; -use rustc_middle::mir::pretty::write_allocation_bytes; use rustc_middle::mir::{self, ConstAlloc, ConstValue}; use rustc_middle::traits::Reveal; use rustc_middle::ty::layout::LayoutOf; @@ -18,8 +17,9 @@ use crate::errors; use crate::errors::ConstEvalError; use crate::interpret::eval_nullary_intrinsic; use crate::interpret::{ - intern_const_alloc_recursive, CtfeValidationMode, GlobalId, Immediate, InternKind, InterpCx, - InterpError, InterpResult, MPlaceTy, MemoryKind, OpTy, RefTracking, StackPopCleanup, + create_static_alloc, intern_const_alloc_recursive, take_static_root_alloc, CtfeValidationMode, + GlobalId, Immediate, InternKind, InterpCx, InterpError, InterpResult, MPlaceTy, MemoryKind, + OpTy, RefTracking, StackPopCleanup, }; // Returns a pointer to where the result lives @@ -47,7 +47,21 @@ fn eval_body_using_ecx<'mir, 'tcx>( ); let layout = ecx.layout_of(body.bound_return_ty().instantiate(tcx, cid.instance.args))?; assert!(layout.is_sized()); - let ret = ecx.allocate(layout, MemoryKind::Stack)?; + + let intern_kind = if cid.promoted.is_some() { + InternKind::Promoted + } else { + match tcx.static_mutability(cid.instance.def_id()) { + Some(m) => InternKind::Static(m), + None => InternKind::Constant, + } + }; + + let ret = if let InternKind::Static(_) = intern_kind { + create_static_alloc(ecx, cid.instance.def_id(), layout)? + } else { + ecx.allocate(layout, MemoryKind::Stack)? + }; trace!( "eval_body_using_ecx: pushing stack frame for global: {}{}", @@ -67,14 +81,6 @@ fn eval_body_using_ecx<'mir, 'tcx>( while ecx.step()? {} // Intern the result - let intern_kind = if cid.promoted.is_some() { - InternKind::Promoted - } else { - match tcx.static_mutability(cid.instance.def_id()) { - Some(m) => InternKind::Static(m), - None => InternKind::Constant, - } - }; intern_const_alloc_recursive(ecx, intern_kind, &ret)?; Ok(ret) @@ -259,7 +265,7 @@ pub fn eval_static_initializer_provider<'tcx>( let instance = ty::Instance::mono(tcx, def_id.to_def_id()); let cid = rustc_middle::mir::interpret::GlobalId { instance, promoted: None }; - let ecx = InterpCx::new( + let mut ecx = InterpCx::new( tcx, tcx.def_span(def_id), ty::ParamEnv::reveal_all(), @@ -267,8 +273,9 @@ pub fn eval_static_initializer_provider<'tcx>( // they do not have to behave "as if" they were evaluated at runtime. CompileTimeInterpreter::new(CanAccessMutGlobal::Yes, CheckAlignment::Error), ); - let alloc_id = eval_in_interpreter(ecx, cid, true)?.alloc_id; - let alloc = tcx.global_alloc(alloc_id).unwrap_memory(); + let alloc_id = eval_in_interpreter(&mut ecx, cid, true)?.alloc_id; + let alloc = take_static_root_alloc(&mut ecx, alloc_id); + let alloc = tcx.mk_const_alloc(alloc); Ok(alloc) } @@ -299,7 +306,7 @@ pub fn eval_to_allocation_raw_provider<'tcx>( let def = cid.instance.def.def_id(); let is_static = tcx.is_static(def); - let ecx = InterpCx::new( + let mut ecx = InterpCx::new( tcx, tcx.def_span(def), key.param_env, @@ -309,11 +316,11 @@ pub fn eval_to_allocation_raw_provider<'tcx>( // so we have to reject reading mutable global memory. CompileTimeInterpreter::new(CanAccessMutGlobal::from(is_static), CheckAlignment::Error), ); - eval_in_interpreter(ecx, cid, is_static) + eval_in_interpreter(&mut ecx, cid, is_static) } pub fn eval_in_interpreter<'mir, 'tcx>( - mut ecx: InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>>, + ecx: &mut InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>>, cid: GlobalId<'tcx>, is_static: bool, ) -> ::rustc_middle::mir::interpret::EvalToAllocationRawResult<'tcx> { @@ -321,7 +328,7 @@ pub fn eval_in_interpreter<'mir, 'tcx>( debug_assert_eq!(is_static, ecx.tcx.static_mutability(cid.instance.def_id()).is_some()); let res = ecx.load_mir(cid.instance.def, cid.promoted); - match res.and_then(|body| eval_body_using_ecx(&mut ecx, cid, body)) { + match res.and_then(|body| eval_body_using_ecx(ecx, cid, body)) { Err(error) => { let (error, backtrace) = error.into_parts(); backtrace.print_backtrace(); @@ -356,8 +363,11 @@ pub fn eval_in_interpreter<'mir, 'tcx>( } Ok(mplace) => { // Since evaluation had no errors, validate the resulting constant. - // This is a separate `try` block to provide more targeted error reporting. + + // Temporarily allow access to the static_root_alloc_id for the purpose of validation. + let static_root_alloc_id = ecx.machine.static_root_alloc_id.take(); let validation = const_validate_mplace(&ecx, &mplace, cid); + ecx.machine.static_root_alloc_id = static_root_alloc_id; let alloc_id = mplace.ptr().provenance.unwrap().alloc_id(); @@ -409,15 +419,9 @@ pub fn const_report_error<'mir, 'tcx>( let ub_note = matches!(error, InterpError::UndefinedBehavior(_)).then(|| {}); - let alloc = ecx.tcx.global_alloc(alloc_id).unwrap_memory().inner(); - let mut bytes = String::new(); - if alloc.size() != abi::Size::ZERO { - bytes = "\n".into(); - // FIXME(translation) there might be pieces that are translatable. - write_allocation_bytes(*ecx.tcx, alloc, &mut bytes, " ").unwrap(); - } - let raw_bytes = - errors::RawBytesNote { size: alloc.size().bytes(), align: alloc.align.bytes(), bytes }; + let bytes = ecx.print_alloc_bytes_for_diagnostics(alloc_id); + let (size, align, _) = ecx.get_alloc_info(alloc_id); + let raw_bytes = errors::RawBytesNote { size: size.bytes(), align: align.bytes(), bytes }; crate::const_eval::report( *ecx.tcx, diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs index 5019bec388c..2c60ede7975 100644 --- a/compiler/rustc_const_eval/src/const_eval/machine.rs +++ b/compiler/rustc_const_eval/src/const_eval/machine.rs @@ -58,6 +58,9 @@ pub struct CompileTimeInterpreter<'mir, 'tcx> { /// Whether to check alignment during evaluation. pub(super) check_alignment: CheckAlignment, + + /// Used to prevent reads from a static's base allocation, as that may allow for self-initialization. + pub(crate) static_root_alloc_id: Option, } #[derive(Copy, Clone)] @@ -91,6 +94,7 @@ impl<'mir, 'tcx> CompileTimeInterpreter<'mir, 'tcx> { stack: Vec::new(), can_access_mut_global, check_alignment, + static_root_alloc_id: None, } } } @@ -746,6 +750,17 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir, // Everything else is fine. Ok(()) } + + fn before_alloc_read( + ecx: &InterpCx<'mir, 'tcx, Self>, + alloc_id: AllocId, + ) -> InterpResult<'tcx> { + if Some(alloc_id) == ecx.machine.static_root_alloc_id { + Err(ConstEvalErrKind::RecursiveStatic.into()) + } else { + Ok(()) + } + } } // Please do not add any code below the above `Machine` trait impl. I (oli-obk) plan more cleanups diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs index d45e8a19717..517994d4741 100644 --- a/compiler/rustc_const_eval/src/interpret/eval_context.rs +++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs @@ -899,7 +899,19 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { .local_to_op(self.frame(), mir::RETURN_PLACE, None) .expect("return place should always be live"); let dest = self.frame().return_place.clone(); - let err = self.copy_op_allow_transmute(&op, &dest); + let err = if self.stack().len() == 1 { + // The initializer of constants and statics will get validated separately + // after the constant has been fully evaluated. While we could fall back to the default + // code path, that will cause -Zenforce-validity to cycle on static initializers. + // Reading from a static's memory is not allowed during its evaluation, and will always + // trigger a cycle error. Validation must read from the memory of the current item. + // For Miri this means we do not validate the root frame return value, + // but Miri anyway calls `read_target_isize` on that so separate validation + // is not needed. + self.copy_op_no_dest_validation(&op, &dest) + } else { + self.copy_op_allow_transmute(&op, &dest) + }; trace!("return value: {:?}", self.dump_place(&dest)); // We delay actually short-circuiting on this error until *after* the stack frame is // popped, since we want this error to be attributed to the caller, whose type defines diff --git a/compiler/rustc_const_eval/src/interpret/intern.rs b/compiler/rustc_const_eval/src/interpret/intern.rs index 7feac6156bc..959ec2ca865 100644 --- a/compiler/rustc_const_eval/src/interpret/intern.rs +++ b/compiler/rustc_const_eval/src/interpret/intern.rs @@ -85,6 +85,8 @@ pub enum InternKind { /// /// This *cannot raise an interpreter error*. Doing so is left to validation, which /// tracks where in the value we are and thus can show much better error messages. +/// +/// For `InternKind::Static` the root allocation will not be interned, but must be handled by the caller. #[instrument(level = "debug", skip(ecx))] pub fn intern_const_alloc_recursive< 'mir, @@ -97,12 +99,12 @@ pub fn intern_const_alloc_recursive< ) -> Result<(), ErrorGuaranteed> { // We are interning recursively, and for mutability we are distinguishing the "root" allocation // that we are starting in, and all other allocations that we are encountering recursively. - let (base_mutability, inner_mutability) = match intern_kind { + let (base_mutability, inner_mutability, is_static) = match intern_kind { InternKind::Constant | InternKind::Promoted => { // Completely immutable. Interning anything mutably here can only lead to unsoundness, // since all consts are conceptually independent values but share the same underlying // memory. - (Mutability::Not, Mutability::Not) + (Mutability::Not, Mutability::Not, false) } InternKind::Static(Mutability::Not) => { ( @@ -115,22 +117,31 @@ pub fn intern_const_alloc_recursive< // Inner allocations are never mutable. They can only arise via the "tail // expression" / "outer scope" rule, and we treat them consistently with `const`. Mutability::Not, + true, ) } InternKind::Static(Mutability::Mut) => { // Just make everything mutable. We accept code like // `static mut X = &mut [42]`, so even inner allocations need to be mutable. - (Mutability::Mut, Mutability::Mut) + (Mutability::Mut, Mutability::Mut, true) } }; // Intern the base allocation, and initialize todo list for recursive interning. let base_alloc_id = ret.ptr().provenance.unwrap().alloc_id(); + trace!(?base_alloc_id, ?base_mutability); // First we intern the base allocation, as it requires a different mutability. // This gives us the initial set of nested allocations, which will then all be processed // recursively in the loop below. - let mut todo: Vec<_> = - intern_shallow(ecx, base_alloc_id, base_mutability).unwrap().map(|prov| prov).collect(); + let mut todo: Vec<_> = if is_static { + // Do not steal the root allocation, we need it later for `take_static_root_alloc` + // But still change its mutability to match the requested one. + let alloc = ecx.memory.alloc_map.get_mut(&base_alloc_id).unwrap(); + alloc.1.mutability = base_mutability; + alloc.1.provenance().ptrs().iter().map(|&(_, prov)| prov).collect() + } else { + intern_shallow(ecx, base_alloc_id, base_mutability).unwrap().map(|prov| prov).collect() + }; // We need to distinguish "has just been interned" from "was already in `tcx`", // so we track this in a separate set. let mut just_interned: FxHashSet<_> = std::iter::once(base_alloc_id).collect(); @@ -148,7 +159,17 @@ pub fn intern_const_alloc_recursive< // before validation, and interning doesn't know the type of anything, this means we can't show // better errors. Maybe we should consider doing validation before interning in the future. while let Some(prov) = todo.pop() { + trace!(?prov); let alloc_id = prov.alloc_id(); + + if base_alloc_id == alloc_id && is_static { + // This is a pointer to the static itself. It's ok for a static to refer to itself, + // even mutably. Whether that mutable pointer is legal at all is checked in validation. + // See tests/ui/statics/recursive_interior_mut.rs for how such a situation can occur. + // We also already collected all the nested allocations, so there's no need to do that again. + continue; + } + // Crucially, we check this *before* checking whether the `alloc_id` // has already been interned. The point of this check is to ensure that when // there are multiple pointers to the same allocation, they are *all* immutable. @@ -176,6 +197,7 @@ pub fn intern_const_alloc_recursive< // `&None::>` lead to promotion that can produce mutable pointers. We rely // on the promotion analysis not screwing up to ensure that it is sound to intern // promoteds as immutable. + trace!("found bad mutable pointer"); found_bad_mutable_pointer = true; } if ecx.tcx.try_get_global_alloc(alloc_id).is_some() { diff --git a/compiler/rustc_const_eval/src/interpret/machine.rs b/compiler/rustc_const_eval/src/interpret/machine.rs index b981a1ee2ca..0106ec425bc 100644 --- a/compiler/rustc_const_eval/src/interpret/machine.rs +++ b/compiler/rustc_const_eval/src/interpret/machine.rs @@ -388,6 +388,8 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized { /// 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. + /// + /// This is not invoked for ZST accesses, as no read actually happens. #[inline(always)] fn before_memory_read( _tcx: TyCtxtAt<'tcx>, @@ -399,7 +401,20 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized { Ok(()) } + /// Hook for performing extra checks on any memory read access, + /// that involves an allocation, even ZST reads. + /// + /// Used to prevent statics from self-initializing by reading from their own memory + /// as it is being initialized. + fn before_alloc_read( + _ecx: &InterpCx<'mir, 'tcx, Self>, + _alloc_id: AllocId, + ) -> InterpResult<'tcx> { + Ok(()) + } + /// Hook for performing extra checks on a memory write access. + /// This is not invoked for ZST accesses, as no write actually happens. #[inline(always)] fn before_memory_write( _tcx: TyCtxtAt<'tcx>, diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs index 4acf4ed893c..2e642ac15b4 100644 --- a/compiler/rustc_const_eval/src/interpret/memory.rs +++ b/compiler/rustc_const_eval/src/interpret/memory.rs @@ -624,19 +624,20 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { size, CheckInAllocMsg::MemoryAccessTest, |alloc_id, offset, prov| { + // We want to call the hook on *all* accesses that involve an AllocId, + // including zero-sized accesses. That means we have to do it here + // rather than below in the `Some` branch. + M::before_alloc_read(self, alloc_id)?; let alloc = self.get_alloc_raw(alloc_id)?; Ok((alloc.size(), alloc.align, (alloc_id, offset, prov, alloc))) }, )?; + if let Some((alloc_id, offset, prov, alloc)) = ptr_and_alloc { let range = alloc_range(offset, size); M::before_memory_read(self.tcx, &self.machine, &alloc.extra, (alloc_id, prov), range)?; Ok(Some(AllocRef { alloc, range, tcx: *self.tcx, alloc_id })) } else { - // Even in this branch we have to be sure that we actually access the allocation, in - // order to ensure that `static FOO: Type = FOO;` causes a cycle error instead of - // magically pulling *any* ZST value from the ether. However, the `get_raw` above is - // always called when `ptr` has an `AllocId`. Ok(None) } } @@ -855,6 +856,21 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { DumpAllocs { ecx: self, allocs } } + /// Print the allocation's bytes, without any nested allocations. + pub fn print_alloc_bytes_for_diagnostics(&self, id: AllocId) -> String { + // Using the "raw" access to avoid the `before_alloc_read` hook, we specifically + // want to be able to read all memory for diagnostics, even if that is cyclic. + let alloc = self.get_alloc_raw(id).unwrap(); + let mut bytes = String::new(); + if alloc.size() != Size::ZERO { + bytes = "\n".into(); + // FIXME(translation) there might be pieces that are translatable. + rustc_middle::mir::pretty::write_allocation_bytes(*self.tcx, alloc, &mut bytes, " ") + .unwrap(); + } + bytes + } + /// Find leaked allocations. Allocations reachable from `static_roots` or a `Global` allocation /// are not considered leaked, as well as leaks whose kind's `may_leak()` returns true. pub fn find_leaked_allocations( diff --git a/compiler/rustc_const_eval/src/interpret/mod.rs b/compiler/rustc_const_eval/src/interpret/mod.rs index c1b6ce4eb4e..a15e52d07e6 100644 --- a/compiler/rustc_const_eval/src/interpret/mod.rs +++ b/compiler/rustc_const_eval/src/interpret/mod.rs @@ -39,4 +39,5 @@ use self::{ }; pub(crate) use self::intrinsics::eval_nullary_intrinsic; +pub(crate) use self::util::{create_static_alloc, take_static_root_alloc}; use eval_context::{from_known_layout, mir_assign_valid_types}; diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs index 807d3804d1c..6e987784ff9 100644 --- a/compiler/rustc_const_eval/src/interpret/place.rs +++ b/compiler/rustc_const_eval/src/interpret/place.rs @@ -758,6 +758,22 @@ where Ok(()) } + /// Copies the data from an operand to a place. + /// The layouts of the `src` and `dest` may disagree. + /// Does not perform validation of the destination. + /// The only known use case for this function is checking the return + /// value of a static during stack frame popping. + #[inline(always)] + pub(super) fn copy_op_no_dest_validation( + &mut self, + src: &impl Readable<'tcx, M::Provenance>, + dest: &impl Writeable<'tcx, M::Provenance>, + ) -> InterpResult<'tcx> { + self.copy_op_inner( + src, dest, /* allow_transmute */ true, /* validate_dest */ false, + ) + } + /// Copies the data from an operand to a place. /// The layouts of the `src` and `dest` may disagree. #[inline(always)] @@ -766,17 +782,22 @@ where src: &impl Readable<'tcx, M::Provenance>, dest: &impl Writeable<'tcx, M::Provenance>, ) -> InterpResult<'tcx> { - self.copy_op_inner(src, dest, /* allow_transmute */ true) + self.copy_op_inner( + src, dest, /* allow_transmute */ true, /* validate_dest */ true, + ) } /// Copies the data from an operand to a place. + /// `src` and `dest` must have the same layout and the copied value will be validated. #[inline(always)] pub fn copy_op( &mut self, src: &impl Readable<'tcx, M::Provenance>, dest: &impl Writeable<'tcx, M::Provenance>, ) -> InterpResult<'tcx> { - self.copy_op_inner(src, dest, /* allow_transmute */ false) + self.copy_op_inner( + src, dest, /* allow_transmute */ false, /* validate_dest */ true, + ) } /// Copies the data from an operand to a place. @@ -788,6 +809,7 @@ where src: &impl Readable<'tcx, M::Provenance>, dest: &impl Writeable<'tcx, M::Provenance>, allow_transmute: bool, + validate_dest: bool, ) -> InterpResult<'tcx> { // Generally for transmutation, data must be valid both at the old and new type. // But if the types are the same, the 2nd validation below suffices. @@ -798,7 +820,7 @@ where // Do the actual copy. self.copy_op_no_validate(src, dest, allow_transmute)?; - if M::enforce_validity(self, dest.layout()) { + if validate_dest && M::enforce_validity(self, dest.layout()) { // Data got changed, better make sure it matches the type! self.validate_operand(&dest.to_op(self)?)?; } diff --git a/compiler/rustc_const_eval/src/interpret/util.rs b/compiler/rustc_const_eval/src/interpret/util.rs index 3a9ee904734..2a13671a829 100644 --- a/compiler/rustc_const_eval/src/interpret/util.rs +++ b/compiler/rustc_const_eval/src/interpret/util.rs @@ -1,9 +1,15 @@ -use rustc_middle::mir::interpret::InterpResult; +use crate::const_eval::CompileTimeEvalContext; +use crate::interpret::{MemPlaceMeta, MemoryKind}; +use rustc_middle::mir::interpret::{AllocId, Allocation, InterpResult, Pointer}; +use rustc_middle::ty::layout::TyAndLayout; use rustc_middle::ty::{ self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor, }; +use rustc_span::def_id::DefId; use std::ops::ControlFlow; +use super::MPlaceTy; + /// Checks whether a type contains generic parameters which must be instantiated. /// /// In case it does, returns a `TooGeneric` const eval error. Note that due to polymorphization @@ -73,3 +79,23 @@ where Ok(()) } } + +pub(crate) fn take_static_root_alloc<'mir, 'tcx: 'mir>( + ecx: &mut CompileTimeEvalContext<'mir, 'tcx>, + alloc_id: AllocId, +) -> Allocation { + ecx.memory.alloc_map.swap_remove(&alloc_id).unwrap().1 +} + +pub(crate) fn create_static_alloc<'mir, 'tcx: 'mir>( + ecx: &mut CompileTimeEvalContext<'mir, 'tcx>, + static_def_id: DefId, + layout: TyAndLayout<'tcx>, +) -> InterpResult<'tcx, MPlaceTy<'tcx>> { + let alloc = Allocation::try_uninit(layout.size, layout.align.abi)?; + let alloc_id = ecx.tcx.reserve_and_set_static_alloc(static_def_id); + assert_eq!(ecx.machine.static_root_alloc_id, None); + ecx.machine.static_root_alloc_id = Some(alloc_id); + assert!(ecx.memory.alloc_map.insert(alloc_id, (MemoryKind::Stack, alloc)).is_none()); + Ok(ecx.ptr_with_meta_to_mplace(Pointer::from(alloc_id).into(), MemPlaceMeta::None, layout)) +} diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs index eb9f3fee165..08a2e38bfa1 100644 --- a/compiler/rustc_const_eval/src/interpret/validity.rs +++ b/compiler/rustc_const_eval/src/interpret/validity.rs @@ -27,9 +27,9 @@ use rustc_target::abi::{ use std::hash::Hash; use super::{ - format_interp_error, AllocId, CheckInAllocMsg, GlobalAlloc, ImmTy, Immediate, InterpCx, - InterpResult, MPlaceTy, Machine, MemPlaceMeta, OpTy, Pointer, Projectable, Scalar, - ValueVisitor, + format_interp_error, machine::AllocMap, AllocId, CheckInAllocMsg, GlobalAlloc, ImmTy, + Immediate, InterpCx, InterpResult, MPlaceTy, Machine, MemPlaceMeta, OpTy, Pointer, Projectable, + Scalar, ValueVisitor, }; // for the validation errors @@ -712,11 +712,14 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, ' fn in_mutable_memory(&self, op: &OpTy<'tcx, M::Provenance>) -> bool { if let Some(mplace) = op.as_mplace_or_imm().left() { if let Some(alloc_id) = mplace.ptr().provenance.and_then(|p| p.get_alloc_id()) { - if self.ecx.tcx.global_alloc(alloc_id).unwrap_memory().inner().mutability - == Mutability::Mut - { - return true; - } + let mutability = match self.ecx.tcx.global_alloc(alloc_id) { + GlobalAlloc::Static(_) => { + self.ecx.memory.alloc_map.get(alloc_id).unwrap().1.mutability + } + GlobalAlloc::Memory(alloc) => alloc.inner().mutability, + _ => span_bug!(self.ecx.tcx.span, "not a memory allocation"), + }; + return mutability == Mutability::Mut; } } false diff --git a/tests/ui/consts/recursive-zst-static.default.stderr b/tests/ui/consts/recursive-zst-static.default.stderr index 9e31209204b..7679c50c74b 100644 --- a/tests/ui/consts/recursive-zst-static.default.stderr +++ b/tests/ui/consts/recursive-zst-static.default.stderr @@ -1,21 +1,35 @@ -error[E0391]: cycle detected when evaluating initializer of static `FOO` +error[E0080]: could not evaluate static initializer --> $DIR/recursive-zst-static.rs:10:18 | LL | static FOO: () = FOO; - | ^^^ + | ^^^ encountered static that tried to initialize itself with itself + +error[E0391]: cycle detected when evaluating initializer of static `A` + --> $DIR/recursive-zst-static.rs:13:16 | - = note: ...which immediately requires evaluating initializer of static `FOO` again +LL | static A: () = B; + | ^ + | +note: ...which requires evaluating initializer of static `B`... + --> $DIR/recursive-zst-static.rs:14:16 + | +LL | static B: () = A; + | ^ + = note: ...which again requires evaluating initializer of static `A`, completing the cycle note: cycle used when linting top-level module --> $DIR/recursive-zst-static.rs:10:1 | LL | / static FOO: () = FOO; LL | | -LL | | fn main() { +LL | | +LL | | static A: () = B; +... | LL | | FOO LL | | } | |_^ = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information -error: aborting due to 1 previous error +error: aborting due to 2 previous errors -For more information about this error, try `rustc --explain E0391`. +Some errors have detailed explanations: E0080, E0391. +For more information about an error, try `rustc --explain E0080`. diff --git a/tests/ui/consts/recursive-zst-static.rs b/tests/ui/consts/recursive-zst-static.rs index 14de00bad8a..9311490020d 100644 --- a/tests/ui/consts/recursive-zst-static.rs +++ b/tests/ui/consts/recursive-zst-static.rs @@ -7,7 +7,11 @@ // can depend on this fact and will thus do unsound things when it is violated. // See https://github.com/rust-lang/rust/issues/71078 for more details. -static FOO: () = FOO; //~ cycle detected when evaluating initializer of static `FOO` +static FOO: () = FOO; +//~^ ERROR could not evaluate static initializer + +static A: () = B; //~ cycle detected when evaluating initializer of static `A` +static B: () = A; fn main() { FOO diff --git a/tests/ui/consts/recursive-zst-static.unleash.stderr b/tests/ui/consts/recursive-zst-static.unleash.stderr index 9e31209204b..7679c50c74b 100644 --- a/tests/ui/consts/recursive-zst-static.unleash.stderr +++ b/tests/ui/consts/recursive-zst-static.unleash.stderr @@ -1,21 +1,35 @@ -error[E0391]: cycle detected when evaluating initializer of static `FOO` +error[E0080]: could not evaluate static initializer --> $DIR/recursive-zst-static.rs:10:18 | LL | static FOO: () = FOO; - | ^^^ + | ^^^ encountered static that tried to initialize itself with itself + +error[E0391]: cycle detected when evaluating initializer of static `A` + --> $DIR/recursive-zst-static.rs:13:16 | - = note: ...which immediately requires evaluating initializer of static `FOO` again +LL | static A: () = B; + | ^ + | +note: ...which requires evaluating initializer of static `B`... + --> $DIR/recursive-zst-static.rs:14:16 + | +LL | static B: () = A; + | ^ + = note: ...which again requires evaluating initializer of static `A`, completing the cycle note: cycle used when linting top-level module --> $DIR/recursive-zst-static.rs:10:1 | LL | / static FOO: () = FOO; LL | | -LL | | fn main() { +LL | | +LL | | static A: () = B; +... | LL | | FOO LL | | } | |_^ = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information -error: aborting due to 1 previous error +error: aborting due to 2 previous errors -For more information about this error, try `rustc --explain E0391`. +Some errors have detailed explanations: E0080, E0391. +For more information about an error, try `rustc --explain E0080`. diff --git a/tests/ui/consts/write-to-static-mut-in-static.rs b/tests/ui/consts/write-to-static-mut-in-static.rs index 43c63fed8ce..a2985d05a79 100644 --- a/tests/ui/consts/write-to-static-mut-in-static.rs +++ b/tests/ui/consts/write-to-static-mut-in-static.rs @@ -3,8 +3,8 @@ pub static mut B: () = unsafe { A = 1; }; //~^ ERROR could not evaluate static initializer pub static mut C: u32 = unsafe { C = 1; 0 }; -//~^ ERROR cycle detected pub static D: u32 = D; +//~^ ERROR could not evaluate static initializer fn main() {} diff --git a/tests/ui/consts/write-to-static-mut-in-static.stderr b/tests/ui/consts/write-to-static-mut-in-static.stderr index 23dd1346ad9..9616f8eeeb7 100644 --- a/tests/ui/consts/write-to-static-mut-in-static.stderr +++ b/tests/ui/consts/write-to-static-mut-in-static.stderr @@ -4,27 +4,12 @@ error[E0080]: could not evaluate static initializer LL | pub static mut B: () = unsafe { A = 1; }; | ^^^^^ modifying a static's initial value from another static's initializer -error[E0391]: cycle detected when evaluating initializer of static `C` - --> $DIR/write-to-static-mut-in-static.rs:5:34 +error[E0080]: could not evaluate static initializer + --> $DIR/write-to-static-mut-in-static.rs:7:21 | -LL | pub static mut C: u32 = unsafe { C = 1; 0 }; - | ^^^^^ - | - = note: ...which immediately requires evaluating initializer of static `C` again -note: cycle used when linting top-level module - --> $DIR/write-to-static-mut-in-static.rs:1:1 - | -LL | / pub static mut A: u32 = 0; -LL | | pub static mut B: () = unsafe { A = 1; }; -LL | | -LL | | -... | -LL | | -LL | | fn main() {} - | |____________^ - = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information +LL | pub static D: u32 = D; + | ^ encountered static that tried to initialize itself with itself error: aborting due to 2 previous errors -Some errors have detailed explanations: E0080, E0391. -For more information about an error, try `rustc --explain E0080`. +For more information about this error, try `rustc --explain E0080`. diff --git a/tests/ui/recursion/recursive-static-definition.rs b/tests/ui/recursion/recursive-static-definition.rs index 74a094a9b01..5317c47076e 100644 --- a/tests/ui/recursion/recursive-static-definition.rs +++ b/tests/ui/recursion/recursive-static-definition.rs @@ -1,4 +1,12 @@ pub static FOO: u32 = FOO; -//~^ ERROR cycle detected when evaluating initializer of static `FOO` +//~^ ERROR could not evaluate static initializer + +#[derive(Copy, Clone)] +pub union Foo { + x: u32, +} + +pub static BAR: Foo = BAR; +//~^ ERROR could not evaluate static initializer fn main() {} diff --git a/tests/ui/recursion/recursive-static-definition.stderr b/tests/ui/recursion/recursive-static-definition.stderr index f071e501e38..86a22c990e9 100644 --- a/tests/ui/recursion/recursive-static-definition.stderr +++ b/tests/ui/recursion/recursive-static-definition.stderr @@ -1,20 +1,15 @@ -error[E0391]: cycle detected when evaluating initializer of static `FOO` +error[E0080]: could not evaluate static initializer --> $DIR/recursive-static-definition.rs:1:23 | LL | pub static FOO: u32 = FOO; - | ^^^ - | - = note: ...which immediately requires evaluating initializer of static `FOO` again -note: cycle used when linting top-level module - --> $DIR/recursive-static-definition.rs:1:1 - | -LL | / pub static FOO: u32 = FOO; -LL | | -LL | | -LL | | fn main() {} - | |____________^ - = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information + | ^^^ encountered static that tried to initialize itself with itself -error: aborting due to 1 previous error +error[E0080]: could not evaluate static initializer + --> $DIR/recursive-static-definition.rs:9:23 + | +LL | pub static BAR: Foo = BAR; + | ^^^ encountered static that tried to initialize itself with itself -For more information about this error, try `rustc --explain E0391`. +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0080`.