diff --git a/src/librustc/mir/interpret/error.rs b/src/librustc/mir/interpret/error.rs index ac99ccd45eafe..71967b513a049 100644 --- a/src/librustc/mir/interpret/error.rs +++ b/src/librustc/mir/interpret/error.rs @@ -389,6 +389,10 @@ pub enum UnsupportedOpInfo<'tcx> { /// Free-form case. Only for errors that are never caught! Unsupported(String), + /// FIXME(#64506) Error used to work around accessing projections of + /// uninhabited types. + UninhabitedValue, + // -- Everything below is not categorized yet -- FunctionAbiMismatch(Abi, Abi), FunctionArgMismatch(Ty<'tcx>, Ty<'tcx>), @@ -552,6 +556,8 @@ impl fmt::Debug for UnsupportedOpInfo<'tcx> { not a power of two"), Unsupported(ref msg) => write!(f, "{}", msg), + UninhabitedValue => + write!(f, "tried to use an uninhabited value"), } } } diff --git a/src/librustc_mir/const_eval.rs b/src/librustc_mir/const_eval.rs index ca238867421ab..bb02b99dd8d87 100644 --- a/src/librustc_mir/const_eval.rs +++ b/src/librustc_mir/const_eval.rs @@ -21,7 +21,7 @@ use syntax::source_map::{Span, DUMMY_SP}; use crate::interpret::{self, PlaceTy, MPlaceTy, OpTy, ImmTy, Immediate, Scalar, Pointer, - RawConst, ConstValue, + RawConst, ConstValue, Machine, InterpResult, InterpErrorInfo, GlobalId, InterpCx, StackPopCleanup, Allocation, AllocId, MemoryKind, Memory, snapshot, RefTracking, intern_const_alloc_recursive, @@ -41,7 +41,7 @@ const DETECTOR_SNAPSHOT_PERIOD: isize = 256; /// that inform us about the generic bounds of the constant. E.g., using an associated constant /// of a function's generic parameter will require knowledge about the bounds on the generic /// parameter. These bounds are passed to `mk_eval_cx` via the `ParamEnv` argument. -pub(crate) fn mk_eval_cx<'mir, 'tcx>( +fn mk_eval_cx<'mir, 'tcx>( tcx: TyCtxt<'tcx>, span: Span, param_env: ty::ParamEnv<'tcx>, @@ -169,7 +169,7 @@ fn eval_body_using_ecx<'mir, 'tcx>( } #[derive(Clone, Debug)] -enum ConstEvalError { +pub enum ConstEvalError { NeedsRfc(String), } @@ -521,8 +521,8 @@ pub fn const_variant_index<'tcx>( /// Turn an interpreter error into something to report to the user. /// As a side-effect, if RUSTC_CTFE_BACKTRACE is set, this prints the backtrace. /// Should be called only if the error is actually going to to be reported! -pub fn error_to_const_error<'mir, 'tcx>( - ecx: &InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>>, +pub fn error_to_const_error<'mir, 'tcx, M: Machine<'mir, 'tcx>>( + ecx: &InterpCx<'mir, 'tcx, M>, mut error: InterpErrorInfo<'tcx>, ) -> ConstEvalErr<'tcx> { error.print_backtrace(); diff --git a/src/librustc_mir/interpret/machine.rs b/src/librustc_mir/interpret/machine.rs index bb74a50156e56..c30c59bbf10c8 100644 --- a/src/librustc_mir/interpret/machine.rs +++ b/src/librustc_mir/interpret/machine.rs @@ -12,6 +12,7 @@ use rustc::ty::{self, Ty, TyCtxt}; use super::{ Allocation, AllocId, InterpResult, Scalar, AllocationExtra, InterpCx, PlaceTy, OpTy, ImmTy, MemoryKind, Pointer, Memory, + Frame, Operand, }; /// Whether this kind of memory is allowed to leak @@ -184,6 +185,22 @@ pub trait Machine<'mir, 'tcx>: Sized { dest: PlaceTy<'tcx, Self::PointerTag>, ) -> InterpResult<'tcx>; + /// Called to read the specified `local` from the `frame`. + fn access_local( + _ecx: &InterpCx<'mir, 'tcx, Self>, + frame: &Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>, + local: mir::Local, + ) -> InterpResult<'tcx, Operand> { + frame.locals[local].access() + } + + /// Called before a `StaticKind::Static` value is accessed. + fn before_access_static( + _allocation: &Allocation, + ) -> InterpResult<'tcx> { + Ok(()) + } + /// Called to initialize the "extra" state of an allocation and make the pointers /// it contains (in relocations) tagged. The way we construct allocations is /// to always first construct it without extra and then add the extra. diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs index 62b1760508b4c..924474c53175c 100644 --- a/src/librustc_mir/interpret/memory.rs +++ b/src/librustc_mir/interpret/memory.rs @@ -462,6 +462,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> { // Make sure we use the ID of the resolved memory, not the lazy one! let id = raw_const.alloc_id; let allocation = tcx.alloc_map.lock().unwrap_memory(id); + + M::before_access_static(allocation)?; Cow::Borrowed(allocation) } } diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs index f5d1ec3eb7556..861e5ebef877d 100644 --- a/src/librustc_mir/interpret/operand.rs +++ b/src/librustc_mir/interpret/operand.rs @@ -458,7 +458,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { // Do not read from ZST, they might not be initialized Operand::Immediate(Scalar::zst().into()) } else { - frame.locals[local].access()? + M::access_local(&self, frame, local)? }; Ok(OpTy { op, layout }) } @@ -481,7 +481,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { // Evaluate a place with the goal of reading from it. This lets us sometimes // avoid allocations. - pub(super) fn eval_place_to_op( + pub fn eval_place_to_op( &self, place: &mir::Place<'tcx>, layout: Option>, diff --git a/src/librustc_mir/interpret/place.rs b/src/librustc_mir/interpret/place.rs index 2f1b35757fe9c..1166ca9bf2444 100644 --- a/src/librustc_mir/interpret/place.rs +++ b/src/librustc_mir/interpret/place.rs @@ -9,7 +9,7 @@ use rustc::mir; use rustc::mir::interpret::truncate; use rustc::ty::{self, Ty}; use rustc::ty::layout::{ - self, Size, Align, LayoutOf, TyLayout, HasDataLayout, VariantIdx, PrimitiveExt + self, Size, Abi, Align, LayoutOf, TyLayout, HasDataLayout, VariantIdx, PrimitiveExt }; use rustc::ty::TypeFoldable; @@ -385,6 +385,10 @@ where stride * field } layout::FieldPlacement::Union(count) => { + // FIXME(#64506) `UninhabitedValue` can be removed when this issue is resolved + if base.layout.abi == Abi::Uninhabited { + throw_unsup!(UninhabitedValue); + } assert!(field < count as u64, "Tried to access field {} of union with {} fields", field, count); // Offset is always 0 diff --git a/src/librustc_mir/interpret/step.rs b/src/librustc_mir/interpret/step.rs index affca10bf5265..daca7a25787ca 100644 --- a/src/librustc_mir/interpret/step.rs +++ b/src/librustc_mir/interpret/step.rs @@ -132,7 +132,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { /// /// There is no separate `eval_rvalue` function. Instead, the code for handling each rvalue /// type writes its results directly into the memory specified by the place. - fn eval_rvalue_into_place( + pub fn eval_rvalue_into_place( &mut self, rvalue: &mir::Rvalue<'tcx>, place: &mir::Place<'tcx>, diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs index 857757ada53b7..612822b6d9d34 100644 --- a/src/librustc_mir/transform/const_prop.rs +++ b/src/librustc_mir/transform/const_prop.rs @@ -1,22 +1,26 @@ //! Propagates constants for early reporting of statically known //! assertion failures +use std::borrow::Cow; use std::cell::Cell; use rustc::hir::def::DefKind; +use rustc::hir::def_id::DefId; use rustc::mir::{ AggregateKind, Constant, Location, Place, PlaceBase, Body, Operand, Rvalue, - Local, NullOp, UnOp, StatementKind, Statement, LocalKind, Static, StaticKind, - TerminatorKind, Terminator, ClearCrossCrate, SourceInfo, BinOp, ProjectionElem, - SourceScope, SourceScopeLocalData, LocalDecl, + Local, NullOp, UnOp, StatementKind, Statement, LocalKind, + TerminatorKind, Terminator, ClearCrossCrate, SourceInfo, BinOp, + SourceScope, SourceScopeLocalData, LocalDecl, BasicBlock, }; use rustc::mir::visit::{ Visitor, PlaceContext, MutatingUseContext, MutVisitor, NonMutatingUseContext, }; -use rustc::mir::interpret::{Scalar, GlobalId, InterpResult, PanicInfo}; +use rustc::mir::interpret::{Scalar, InterpResult, PanicInfo}; use rustc::ty::{self, Instance, ParamEnv, Ty, TyCtxt}; +use syntax::ast::Mutability; use syntax_pos::{Span, DUMMY_SP}; use rustc::ty::subst::InternalSubsts; +use rustc_data_structures::fx::FxHashMap; use rustc_data_structures::indexed_vec::IndexVec; use rustc::ty::layout::{ LayoutOf, TyLayout, LayoutError, HasTyCtxt, TargetDataLayout, HasDataLayout, @@ -24,11 +28,11 @@ use rustc::ty::layout::{ use crate::interpret::{ self, InterpCx, ScalarMaybeUndef, Immediate, OpTy, - ImmTy, MemoryKind, StackPopCleanup, LocalValue, LocalState, -}; -use crate::const_eval::{ - CompileTimeInterpreter, error_to_const_error, mk_eval_cx, + StackPopCleanup, LocalValue, LocalState, AllocId, Frame, + Allocation, MemoryKind, ImmTy, Pointer, Memory, PlaceTy, + Operand as InterpOperand, }; +use crate::const_eval::error_to_const_error; use crate::transform::{MirPass, MirSource}; pub struct ConstProp; @@ -57,6 +61,14 @@ impl<'tcx> MirPass<'tcx> for ConstProp { return } + let is_generator = tcx.type_of(source.def_id()).is_generator(); + // FIXME(welseywiser) const prop doesn't work on generators because of query cycles + // computing their layout. + if is_generator { + trace!("ConstProp skipped for generator {:?}", source.def_id()); + return + } + trace!("ConstProp starting for {:?}", source.def_id()); // Steal some data we need from `body`. @@ -103,11 +115,154 @@ impl<'tcx> MirPass<'tcx> for ConstProp { } } +struct ConstPropMachine; + +impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine { + type MemoryKinds= !; + type PointerTag = (); + type ExtraFnVal = !; + + type FrameExtra = (); + type MemoryExtra = (); + type AllocExtra = (); + + type MemoryMap = FxHashMap, Allocation)>; + + const STATIC_KIND: Option = None; + + const CHECK_ALIGN: bool = false; + + #[inline(always)] + fn enforce_validity(_ecx: &InterpCx<'mir, 'tcx, Self>) -> bool { + false + } + + fn find_fn( + _ecx: &mut InterpCx<'mir, 'tcx, Self>, + _instance: ty::Instance<'tcx>, + _args: &[OpTy<'tcx>], + _dest: Option>, + _ret: Option, + ) -> InterpResult<'tcx, Option<&'mir Body<'tcx>>> { + Ok(None) + } + + fn call_extra_fn( + _ecx: &mut InterpCx<'mir, 'tcx, Self>, + fn_val: !, + _args: &[OpTy<'tcx>], + _dest: Option>, + _ret: Option, + ) -> InterpResult<'tcx> { + match fn_val {} + } + + fn call_intrinsic( + _ecx: &mut InterpCx<'mir, 'tcx, Self>, + _instance: ty::Instance<'tcx>, + _args: &[OpTy<'tcx>], + _dest: PlaceTy<'tcx>, + ) -> InterpResult<'tcx> { + throw_unsup_format!("calling intrinsics isn't supported in ConstProp"); + } + + fn ptr_to_int( + _mem: &Memory<'mir, 'tcx, Self>, + _ptr: Pointer, + ) -> InterpResult<'tcx, u64> { + throw_unsup_format!("ptr-to-int casts aren't supported in ConstProp"); + } + + fn binary_ptr_op( + _ecx: &InterpCx<'mir, 'tcx, Self>, + _bin_op: BinOp, + _left: ImmTy<'tcx>, + _right: ImmTy<'tcx>, + ) -> InterpResult<'tcx, (Scalar, bool, Ty<'tcx>)> { + // We can't do this because aliasing of memory can differ between const eval and llvm + throw_unsup_format!("pointer arithmetic or comparisons aren't supported in ConstProp"); + } + + fn find_foreign_static( + _tcx: TyCtxt<'tcx>, + _def_id: DefId, + ) -> InterpResult<'tcx, Cow<'tcx, Allocation>> { + throw_unsup!(ReadForeignStatic) + } + + #[inline(always)] + fn tag_allocation<'b>( + _memory_extra: &(), + _id: AllocId, + alloc: Cow<'b, Allocation>, + _kind: Option>, + ) -> (Cow<'b, Allocation>, Self::PointerTag) { + // We do not use a tag so we can just cheaply forward the allocation + (alloc, ()) + } + + #[inline(always)] + fn tag_static_base_pointer( + _memory_extra: &(), + _id: AllocId, + ) -> Self::PointerTag { + () + } + + fn box_alloc( + _ecx: &mut InterpCx<'mir, 'tcx, Self>, + _dest: PlaceTy<'tcx>, + ) -> InterpResult<'tcx> { + throw_unsup_format!("can't const prop `box` keyword"); + } + + fn access_local( + _ecx: &InterpCx<'mir, 'tcx, Self>, + frame: &Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>, + local: Local, + ) -> InterpResult<'tcx, InterpOperand> { + let l = &frame.locals[local]; + + if l.value == LocalValue::Uninitialized { + throw_unsup_format!("tried to access an uninitialized local"); + } + + l.access() + } + + fn before_access_static( + allocation: &Allocation, + ) -> 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::Mutable || allocation.relocations().len() > 0 { + throw_unsup_format!("can't eval mutable statics in ConstProp"); + } + + Ok(()) + } + + fn before_terminator(_ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> { + Ok(()) + } + + #[inline(always)] + fn stack_push(_ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> { + Ok(()) + } + + /// Called immediately before a stack frame gets popped. + #[inline(always)] + fn stack_pop(_ecx: &mut InterpCx<'mir, 'tcx, Self>, _extra: ()) -> InterpResult<'tcx> { + Ok(()) + } +} + type Const<'tcx> = OpTy<'tcx>; /// Finds optimization opportunities on the MIR. struct ConstPropagator<'mir, 'tcx> { - ecx: InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>>, + ecx: InterpCx<'mir, 'tcx, ConstPropMachine>, tcx: TyCtxt<'tcx>, source: MirSource<'tcx>, can_const_prop: IndexVec, @@ -150,7 +305,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { let def_id = source.def_id(); let param_env = tcx.param_env(def_id); let span = tcx.def_span(def_id); - let mut ecx = mk_eval_cx(tcx, span, param_env); + let mut ecx = InterpCx::new(tcx.at(span), param_env, ConstPropMachine, ()); let can_const_prop = CanConstProp::check(body); ecx.push_stack_frame( @@ -282,53 +437,9 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { fn eval_place(&mut self, place: &Place<'tcx>, source_info: SourceInfo) -> Option> { trace!("eval_place(place={:?})", place); - let mut eval = match place.base { - PlaceBase::Local(loc) => self.get_const(loc).clone()?, - PlaceBase::Static(box Static {kind: StaticKind::Promoted(promoted, _), ..}) => { - let generics = self.tcx.generics_of(self.source.def_id()); - if generics.requires_monomorphization(self.tcx) { - // FIXME: can't handle code with generics - return None; - } - let substs = InternalSubsts::identity_for_item(self.tcx, self.source.def_id()); - let instance = Instance::new(self.source.def_id(), substs); - let cid = GlobalId { - instance, - promoted: Some(promoted), - }; - let res = self.use_ecx(source_info, |this| { - this.ecx.const_eval_raw(cid) - })?; - trace!("evaluated promoted {:?} to {:?}", promoted, res); - res.into() - } - _ => return None, - }; - - for (i, elem) in place.projection.iter().enumerate() { - let proj_base = &place.projection[..i]; - - match elem { - ProjectionElem::Field(field, _) => { - trace!("field proj on {:?}", proj_base); - eval = self.use_ecx(source_info, |this| { - this.ecx.operand_field(eval, field.index() as u64) - })?; - }, - ProjectionElem::Deref => { - trace!("processing deref"); - eval = self.use_ecx(source_info, |this| { - this.ecx.deref_operand(eval) - })?.into(); - } - // We could get more projections by using e.g., `operand_projection`, - // but we do not even have the stack frame set up properly so - // an `Index` projection would throw us off-track. - _ => return None, - } - } - - Some(eval) + self.use_ecx(source_info, |this| { + this.ecx.eval_place_to_op(place, None) + }) } fn eval_operand(&mut self, op: &Operand<'tcx>, source_info: SourceInfo) -> Option> { @@ -344,166 +455,118 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { rvalue: &Rvalue<'tcx>, place_layout: TyLayout<'tcx>, source_info: SourceInfo, + place: &Place<'tcx>, ) -> Option> { let span = source_info.span; - match *rvalue { - Rvalue::Use(ref op) => { - self.eval_operand(op, source_info) - }, - Rvalue::Ref(_, _, ref place) => { - let src = self.eval_place(place, source_info)?; - let mplace = src.try_as_mplace().ok()?; - Some(ImmTy::from_scalar(mplace.ptr.into(), place_layout).into()) - }, + + // if this isn't a supported operation, then return None + match rvalue { Rvalue::Repeat(..) | Rvalue::Aggregate(..) | Rvalue::NullaryOp(NullOp::Box, _) | - Rvalue::Discriminant(..) => None, - - Rvalue::Cast(kind, ref operand, _) => { - let op = self.eval_operand(operand, source_info)?; - self.use_ecx(source_info, |this| { - let dest = this.ecx.allocate(place_layout, MemoryKind::Stack); - this.ecx.cast(op, kind, dest.into())?; - Ok(dest.into()) - }) - }, - Rvalue::Len(ref place) => { - let place = self.eval_place(&place, source_info)?; - let mplace = place.try_as_mplace().ok()?; - - if let ty::Slice(_) = mplace.layout.ty.kind { - let len = mplace.meta.unwrap().to_usize(&self.ecx).unwrap(); - - Some(ImmTy::from_uint( - len, - self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?, - ).into()) - } else { - trace!("not slice: {:?}", mplace.layout.ty.kind); - None - } - }, - Rvalue::NullaryOp(NullOp::SizeOf, ty) => { - type_size_of(self.tcx, self.param_env, ty).and_then(|n| Some( - ImmTy::from_uint( - n, - self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?, - ).into() - )) - } - Rvalue::UnaryOp(op, ref arg) => { - let def_id = if self.tcx.is_closure(self.source.def_id()) { - self.tcx.closure_base_def_id(self.source.def_id()) - } else { - self.source.def_id() - }; - let generics = self.tcx.generics_of(def_id); - if generics.requires_monomorphization(self.tcx) { - // FIXME: can't handle code with generics - return None; - } + Rvalue::Discriminant(..) => return None, + + Rvalue::Use(_) | + Rvalue::Len(_) | + Rvalue::Cast(..) | + Rvalue::NullaryOp(..) | + Rvalue::CheckedBinaryOp(..) | + Rvalue::Ref(..) | + Rvalue::UnaryOp(..) | + Rvalue::BinaryOp(..) => { } + } - let arg = self.eval_operand(arg, source_info)?; - let oflo_check = self.tcx.sess.overflow_checks(); - let val = self.use_ecx(source_info, |this| { - let prim = this.ecx.read_immediate(arg)?; - match op { - UnOp::Neg => { - // We check overflow in debug mode already - // so should only check in release mode. - if !oflo_check - && prim.layout.ty.is_signed() - && prim.to_bits()? == (1 << (prim.layout.size.bits() - 1)) { - throw_panic!(OverflowNeg) - } - } - UnOp::Not => { - // Cannot overflow + // perform any special checking for specific Rvalue types + if let Rvalue::UnaryOp(op, arg) = rvalue { + trace!("checking UnaryOp(op = {:?}, arg = {:?})", op, arg); + let overflow_check = self.tcx.sess.overflow_checks(); + + self.use_ecx(source_info, |this| { + // We check overflow in debug mode already + // so should only check in release mode. + if *op == UnOp::Neg && !overflow_check { + let ty = arg.ty(&this.local_decls, this.tcx); + + if ty.is_integral() { + let arg = this.ecx.eval_operand(arg, None)?; + let prim = this.ecx.read_immediate(arg)?; + // Need to do overflow check here: For actual CTFE, MIR + // generation emits code that does this before calling the op. + if prim.to_bits()? == (1 << (prim.layout.size.bits() - 1)) { + throw_panic!(OverflowNeg) } } - // Now run the actual operation. - this.ecx.unary_op(op, prim) - })?; - Some(val.into()) - } - Rvalue::CheckedBinaryOp(op, ref left, ref right) | - Rvalue::BinaryOp(op, ref left, ref right) => { - trace!("rvalue binop {:?} for {:?} and {:?}", op, left, right); - let right = self.eval_operand(right, source_info)?; - let def_id = if self.tcx.is_closure(self.source.def_id()) { - self.tcx.closure_base_def_id(self.source.def_id()) - } else { - self.source.def_id() - }; - let generics = self.tcx.generics_of(def_id); - if generics.requires_monomorphization(self.tcx) { - // FIXME: can't handle code with generics + } + + Ok(()) + })?; + } else if let Rvalue::BinaryOp(op, left, right) = rvalue { + trace!("checking BinaryOp(op = {:?}, left = {:?}, right = {:?})", op, left, right); + + let r = self.use_ecx(source_info, |this| { + this.ecx.read_immediate(this.ecx.eval_operand(right, None)?) + })?; + if *op == BinOp::Shr || *op == BinOp::Shl { + let left_bits = place_layout.size.bits(); + let right_size = r.layout.size; + let r_bits = r.to_scalar().and_then(|r| r.to_bits(right_size)); + if r_bits.ok().map_or(false, |b| b >= left_bits as u128) { + let source_scope_local_data = match self.source_scope_local_data { + ClearCrossCrate::Set(ref data) => data, + ClearCrossCrate::Clear => return None, + }; + let dir = if *op == BinOp::Shr { + "right" + } else { + "left" + }; + let hir_id = source_scope_local_data[source_info.scope].lint_root; + self.tcx.lint_hir( + ::rustc::lint::builtin::EXCEEDING_BITSHIFTS, + hir_id, + span, + &format!("attempt to shift {} with overflow", dir)); return None; } + } + self.use_ecx(source_info, |this| { + let l = this.ecx.read_immediate(this.ecx.eval_operand(left, None)?)?; + let (_, overflow, _ty) = this.ecx.overflowing_binary_op(*op, l, r)?; + + // We check overflow in debug mode already + // so should only check in release mode. + if !this.tcx.sess.overflow_checks() && overflow { + let err = err_panic!(Overflow(*op)).into(); + return Err(err); + } - let r = self.use_ecx(source_info, |this| { - this.ecx.read_immediate(right) - })?; - if op == BinOp::Shr || op == BinOp::Shl { - let left_ty = left.ty(&self.local_decls, self.tcx); - let left_bits = self - .tcx - .layout_of(self.param_env.and(left_ty)) - .unwrap() - .size - .bits(); - let right_size = right.layout.size; - let r_bits = r.to_scalar().and_then(|r| r.to_bits(right_size)); - if r_bits.ok().map_or(false, |b| b >= left_bits as u128) { - let source_scope_local_data = match self.source_scope_local_data { - ClearCrossCrate::Set(ref data) => data, - ClearCrossCrate::Clear => return None, - }; - let dir = if op == BinOp::Shr { - "right" - } else { - "left" - }; - let hir_id = source_scope_local_data[source_info.scope].lint_root; - self.tcx.lint_hir( - ::rustc::lint::builtin::EXCEEDING_BITSHIFTS, - hir_id, - span, - &format!("attempt to shift {} with overflow", dir)); - return None; - } + Ok(()) + })?; + } else if let Rvalue::Ref(_, _, place) = rvalue { + trace!("checking Ref({:?})", place); + // FIXME(wesleywiser) we don't currently handle the case where we try to make a ref + // from a function argument that hasn't been assigned to in this function. + if let Place { + base: PlaceBase::Local(local), + projection: box [] + } = place { + let alive = + if let LocalValue::Live(_) = self.ecx.frame().locals[*local].value { + true + } else { false }; + + if local.as_usize() <= self.ecx.frame().body.arg_count && !alive { + trace!("skipping Ref({:?})", place); + return None; } - let left = self.eval_operand(left, source_info)?; - let l = self.use_ecx(source_info, |this| { - this.ecx.read_immediate(left) - })?; - trace!("const evaluating {:?} for {:?} and {:?}", op, left, right); - let (val, overflow, _ty) = self.use_ecx(source_info, |this| { - this.ecx.overflowing_binary_op(op, l, r) - })?; - let val = if let Rvalue::CheckedBinaryOp(..) = *rvalue { - Immediate::ScalarPair( - val.into(), - Scalar::from_bool(overflow).into(), - ) - } else { - // We check overflow in debug mode already - // so should only check in release mode. - if !self.tcx.sess.overflow_checks() && overflow { - let err = err_panic!(Overflow(op)).into(); - let _: Option<()> = self.use_ecx(source_info, |_| Err(err)); - return None; - } - Immediate::Scalar(val.into()) - }; - let res = ImmTy { - imm: val, - layout: place_layout, - }; - Some(res.into()) - }, + } } + + self.use_ecx(source_info, |this| { + trace!("calling eval_rvalue_into_place(rvalue = {:?}, place = {:?})", rvalue, place); + this.ecx.eval_rvalue_into_place(rvalue, place)?; + this.ecx.eval_place_to_op(place, Some(place_layout)) + }) } fn operand_from_scalar(&self, scalar: Scalar, ty: Ty<'tcx>, span: Span) -> Operand<'tcx> { @@ -577,14 +640,6 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { } } -fn type_size_of<'tcx>( - tcx: TyCtxt<'tcx>, - param_env: ty::ParamEnv<'tcx>, - ty: Ty<'tcx>, -) -> Option { - tcx.layout_of(param_env.and(ty)).ok().map(|layout| layout.size.bytes()) -} - struct CanConstProp { can_const_prop: IndexVec, // false at the beginning, once set, there are not allowed to be any more assignments @@ -670,15 +725,19 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> { .ty(&self.local_decls, self.tcx) .ty; if let Ok(place_layout) = self.tcx.layout_of(self.param_env.and(place_ty)) { - if let Some(value) = self.const_prop(rval, place_layout, statement.source_info) { - if let Place { - base: PlaceBase::Local(local), - projection: box [], - } = *place { + if let Place { + base: PlaceBase::Local(local), + projection: box [], + } = *place { + if let Some(value) = self.const_prop(rval, + place_layout, + statement.source_info, + place) { trace!("checking whether {:?} can be stored to {:?}", value, local); if self.can_const_prop[local] { trace!("storing {:?} to {:?}", value, local); - assert!(self.get_const(local).is_none()); + assert!(self.get_const(local).is_none() || + self.get_const(local) == Some(value)); self.set_const(local, value); if self.should_const_prop() { @@ -692,7 +751,22 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> { } } } + } else { + match statement.kind { + StatementKind::StorageLive(local) | + StatementKind::StorageDead(local) if self.can_const_prop[local] => { + let frame = self.ecx.frame_mut(); + frame.locals[local].value = + if let StatementKind::StorageLive(_) = statement.kind { + LocalValue::Uninitialized + } else { + LocalValue::Dead + }; + } + _ => {} + } } + self.super_statement(statement, location); } diff --git a/src/test/mir-opt/const_prop/read_immutable_static.rs b/src/test/mir-opt/const_prop/read_immutable_static.rs new file mode 100644 index 0000000000000..d16f812ad95db --- /dev/null +++ b/src/test/mir-opt/const_prop/read_immutable_static.rs @@ -0,0 +1,27 @@ +static FOO: u8 = 2; + +fn main() { + let x = FOO + FOO; +} + +// END RUST SOURCE +// START rustc.main.ConstProp.before.mir +// bb0: { +// ... +// _2 = (FOO: u8); +// ... +// _3 = (FOO: u8); +// _1 = Add(move _2, move _3); +// ... +// } +// END rustc.main.ConstProp.before.mir +// START rustc.main.ConstProp.after.mir +// bb0: { +// ... +// _2 = const 2u8; +// ... +// _3 = const 2u8; +// _1 = Add(move _2, move _3); +// ... +// } +// END rustc.main.ConstProp.after.mir diff --git a/src/test/mir-opt/const_prop/reify_fn_ptr.rs b/src/test/mir-opt/const_prop/reify_fn_ptr.rs index 7e36b2a6b1b39..e9b61690cf89e 100644 --- a/src/test/mir-opt/const_prop/reify_fn_ptr.rs +++ b/src/test/mir-opt/const_prop/reify_fn_ptr.rs @@ -16,7 +16,7 @@ fn main() { // START rustc.main.ConstProp.after.mir // bb0: { // ... -// _3 = const Scalar(AllocId(1).0x0) : fn(); +// _3 = const Scalar(AllocId(0).0x0) : fn(); // _2 = move _3 as usize (Misc); // ... // _1 = move _2 as *const fn() (Misc); diff --git a/src/test/mir-opt/const_prop/slice_len.rs b/src/test/mir-opt/const_prop/slice_len.rs index 5babeb195a826..05595ce147c96 100644 --- a/src/test/mir-opt/const_prop/slice_len.rs +++ b/src/test/mir-opt/const_prop/slice_len.rs @@ -34,7 +34,7 @@ fn main() { // assert(const true, "index out of bounds: the len is move _7 but the index is _6") -> bb1; // } // bb1: { -// _1 = (*_2)[_6]; +// _1 = const 2u32; // ... // return; // } diff --git a/src/test/run-fail/overflowing-lsh-1.rs b/src/test/run-fail/overflowing-lsh-1.rs index c69da0f49adf1..37fbf01e487dc 100644 --- a/src/test/run-fail/overflowing-lsh-1.rs +++ b/src/test/run-fail/overflowing-lsh-1.rs @@ -2,6 +2,7 @@ // compile-flags: -C debug-assertions #![warn(exceeding_bitshifts)] +#![warn(const_err)] fn main() { let _x = 1_i32 << 32; diff --git a/src/test/run-fail/overflowing-lsh-2.rs b/src/test/run-fail/overflowing-lsh-2.rs index 21659bd52393a..7b0b37dfed043 100644 --- a/src/test/run-fail/overflowing-lsh-2.rs +++ b/src/test/run-fail/overflowing-lsh-2.rs @@ -2,6 +2,7 @@ // compile-flags: -C debug-assertions #![warn(exceeding_bitshifts)] +#![warn(const_err)] fn main() { let _x = 1 << -1; diff --git a/src/test/run-fail/overflowing-lsh-3.rs b/src/test/run-fail/overflowing-lsh-3.rs index 8f06cd1153354..1768a8e6d3138 100644 --- a/src/test/run-fail/overflowing-lsh-3.rs +++ b/src/test/run-fail/overflowing-lsh-3.rs @@ -2,6 +2,7 @@ // compile-flags: -C debug-assertions #![warn(exceeding_bitshifts)] +#![warn(const_err)] fn main() { let _x = 1_u64 << 64; diff --git a/src/test/run-fail/overflowing-lsh-4.rs b/src/test/run-fail/overflowing-lsh-4.rs index 084c147094dee..ec304b4144e0f 100644 --- a/src/test/run-fail/overflowing-lsh-4.rs +++ b/src/test/run-fail/overflowing-lsh-4.rs @@ -5,6 +5,7 @@ // sidestep the overflow checking. #![warn(exceeding_bitshifts)] +#![warn(const_err)] fn main() { // this signals overflow when checking is on diff --git a/src/test/run-fail/overflowing-rsh-1.rs b/src/test/run-fail/overflowing-rsh-1.rs index 24a77da896d9e..14514540c06e1 100644 --- a/src/test/run-fail/overflowing-rsh-1.rs +++ b/src/test/run-fail/overflowing-rsh-1.rs @@ -2,6 +2,7 @@ // compile-flags: -C debug-assertions #![warn(exceeding_bitshifts)] +#![warn(const_err)] fn main() { let _x = -1_i32 >> 32; diff --git a/src/test/run-fail/overflowing-rsh-2.rs b/src/test/run-fail/overflowing-rsh-2.rs index b5615cacc2055..83dcbd13d2ad8 100644 --- a/src/test/run-fail/overflowing-rsh-2.rs +++ b/src/test/run-fail/overflowing-rsh-2.rs @@ -2,6 +2,7 @@ // compile-flags: -C debug-assertions #![warn(exceeding_bitshifts)] +#![warn(const_err)] fn main() { let _x = -1_i32 >> -1; diff --git a/src/test/run-fail/overflowing-rsh-3.rs b/src/test/run-fail/overflowing-rsh-3.rs index 7598e026d8139..3521c0506591c 100644 --- a/src/test/run-fail/overflowing-rsh-3.rs +++ b/src/test/run-fail/overflowing-rsh-3.rs @@ -2,6 +2,7 @@ // compile-flags: -C debug-assertions #![warn(exceeding_bitshifts)] +#![warn(const_err)] fn main() { let _x = -1_i64 >> 64; diff --git a/src/test/run-fail/overflowing-rsh-4.rs b/src/test/run-fail/overflowing-rsh-4.rs index a8d3b69392a97..ed1191849e57c 100644 --- a/src/test/run-fail/overflowing-rsh-4.rs +++ b/src/test/run-fail/overflowing-rsh-4.rs @@ -5,6 +5,7 @@ // truncation does not sidestep the overflow checking. #![warn(exceeding_bitshifts)] +#![warn(const_err)] fn main() { // this signals overflow when checking is on diff --git a/src/test/ui/consts/const-eval/issue-50814.rs b/src/test/ui/consts/const-eval/issue-50814.rs index b85cecda16e95..274967ef60de5 100644 --- a/src/test/ui/consts/const-eval/issue-50814.rs +++ b/src/test/ui/consts/const-eval/issue-50814.rs @@ -11,6 +11,7 @@ struct Sum(A,B); impl Unsigned for Sum { const MAX: u8 = A::MAX + B::MAX; //~ ERROR any use of this value will cause an error + //~| ERROR any use of this value will cause an error } fn foo(_: T) -> &'static u8 { diff --git a/src/test/ui/consts/const-eval/issue-50814.stderr b/src/test/ui/consts/const-eval/issue-50814.stderr index 707dfee7cd5b8..de3459c72dd2b 100644 --- a/src/test/ui/consts/const-eval/issue-50814.stderr +++ b/src/test/ui/consts/const-eval/issue-50814.stderr @@ -9,13 +9,21 @@ LL | const MAX: u8 = A::MAX + B::MAX; = note: `#[deny(const_err)]` on by default error[E0080]: evaluation of constant expression failed - --> $DIR/issue-50814.rs:17:5 + --> $DIR/issue-50814.rs:18:5 | LL | &Sum::::MAX | ^----------------- | | | referenced constant has errors -error: aborting due to 2 previous errors +error: any use of this value will cause an error + --> $DIR/issue-50814.rs:13:21 + | +LL | const MAX: u8 = A::MAX + B::MAX; + | ----------------^^^^^^^^^^^^^^^- + | | + | attempt to add with overflow + +error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0080`. diff --git a/src/test/ui/consts/const-prop-read-static-in-const.rs b/src/test/ui/consts/const-prop-read-static-in-const.rs new file mode 100644 index 0000000000000..7504fd525955a --- /dev/null +++ b/src/test/ui/consts/const-prop-read-static-in-const.rs @@ -0,0 +1,12 @@ +// compile-flags: -Zunleash-the-miri-inside-of-you +// run-pass + +#![allow(dead_code)] + +const TEST: u8 = MY_STATIC; +//~^ skipping const checks + +static MY_STATIC: u8 = 4; + +fn main() { +} diff --git a/src/test/ui/consts/const-prop-read-static-in-const.stderr b/src/test/ui/consts/const-prop-read-static-in-const.stderr new file mode 100644 index 0000000000000..bbd5b12ed7dfc --- /dev/null +++ b/src/test/ui/consts/const-prop-read-static-in-const.stderr @@ -0,0 +1,6 @@ +warning: skipping const checks + --> $DIR/const-prop-read-static-in-const.rs:6:18 + | +LL | const TEST: u8 = MY_STATIC; + | ^^^^^^^^^ + diff --git a/src/test/ui/lint/lint-exceeding-bitshifts.rs b/src/test/ui/lint/lint-exceeding-bitshifts.rs index 0f397a7efe81f..dd3b839342911 100644 --- a/src/test/ui/lint/lint-exceeding-bitshifts.rs +++ b/src/test/ui/lint/lint-exceeding-bitshifts.rs @@ -1,3 +1,5 @@ +// compile-flags: -O + #![deny(exceeding_bitshifts, const_err)] #![allow(unused_variables)] #![allow(dead_code)] diff --git a/src/test/ui/lint/lint-exceeding-bitshifts.stderr b/src/test/ui/lint/lint-exceeding-bitshifts.stderr index f9f168c14dee3..25e079b6d814f 100644 --- a/src/test/ui/lint/lint-exceeding-bitshifts.stderr +++ b/src/test/ui/lint/lint-exceeding-bitshifts.stderr @@ -1,113 +1,113 @@ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:7:15 + --> $DIR/lint-exceeding-bitshifts.rs:9:15 | LL | let n = 1u8 << 8; | ^^^^^^^^ | note: lint level defined here - --> $DIR/lint-exceeding-bitshifts.rs:1:9 + --> $DIR/lint-exceeding-bitshifts.rs:3:9 | LL | #![deny(exceeding_bitshifts, const_err)] | ^^^^^^^^^^^^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:9:15 + --> $DIR/lint-exceeding-bitshifts.rs:11:15 | LL | let n = 1u16 << 16; | ^^^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:11:15 + --> $DIR/lint-exceeding-bitshifts.rs:13:15 | LL | let n = 1u32 << 32; | ^^^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:13:15 + --> $DIR/lint-exceeding-bitshifts.rs:15:15 | LL | let n = 1u64 << 64; | ^^^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:15:15 + --> $DIR/lint-exceeding-bitshifts.rs:17:15 | LL | let n = 1i8 << 8; | ^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:17:15 + --> $DIR/lint-exceeding-bitshifts.rs:19:15 | LL | let n = 1i16 << 16; | ^^^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:19:15 + --> $DIR/lint-exceeding-bitshifts.rs:21:15 | LL | let n = 1i32 << 32; | ^^^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:21:15 + --> $DIR/lint-exceeding-bitshifts.rs:23:15 | LL | let n = 1i64 << 64; | ^^^^^^^^^^ error: attempt to shift right with overflow - --> $DIR/lint-exceeding-bitshifts.rs:24:15 + --> $DIR/lint-exceeding-bitshifts.rs:26:15 | LL | let n = 1u8 >> 8; | ^^^^^^^^ error: attempt to shift right with overflow - --> $DIR/lint-exceeding-bitshifts.rs:26:15 + --> $DIR/lint-exceeding-bitshifts.rs:28:15 | LL | let n = 1u16 >> 16; | ^^^^^^^^^^ error: attempt to shift right with overflow - --> $DIR/lint-exceeding-bitshifts.rs:28:15 + --> $DIR/lint-exceeding-bitshifts.rs:30:15 | LL | let n = 1u32 >> 32; | ^^^^^^^^^^ error: attempt to shift right with overflow - --> $DIR/lint-exceeding-bitshifts.rs:30:15 + --> $DIR/lint-exceeding-bitshifts.rs:32:15 | LL | let n = 1u64 >> 64; | ^^^^^^^^^^ error: attempt to shift right with overflow - --> $DIR/lint-exceeding-bitshifts.rs:32:15 + --> $DIR/lint-exceeding-bitshifts.rs:34:15 | LL | let n = 1i8 >> 8; | ^^^^^^^^ error: attempt to shift right with overflow - --> $DIR/lint-exceeding-bitshifts.rs:34:15 + --> $DIR/lint-exceeding-bitshifts.rs:36:15 | LL | let n = 1i16 >> 16; | ^^^^^^^^^^ error: attempt to shift right with overflow - --> $DIR/lint-exceeding-bitshifts.rs:36:15 + --> $DIR/lint-exceeding-bitshifts.rs:38:15 | LL | let n = 1i32 >> 32; | ^^^^^^^^^^ error: attempt to shift right with overflow - --> $DIR/lint-exceeding-bitshifts.rs:38:15 + --> $DIR/lint-exceeding-bitshifts.rs:40:15 | LL | let n = 1i64 >> 64; | ^^^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:42:15 + --> $DIR/lint-exceeding-bitshifts.rs:44:15 | LL | let n = n << 8; | ^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts.rs:44:15 + --> $DIR/lint-exceeding-bitshifts.rs:46:15 | LL | let n = 1u8 << -8; | ^^^^^^^^^ diff --git a/src/test/ui/lint/lint-exceeding-bitshifts2.rs b/src/test/ui/lint/lint-exceeding-bitshifts2.rs index bde4865aa3f9e..69b627355b801 100644 --- a/src/test/ui/lint/lint-exceeding-bitshifts2.rs +++ b/src/test/ui/lint/lint-exceeding-bitshifts2.rs @@ -1,3 +1,5 @@ +// compile-flags: -O + #![deny(exceeding_bitshifts, const_err)] #![allow(unused_variables)] #![allow(dead_code)] diff --git a/src/test/ui/lint/lint-exceeding-bitshifts2.stderr b/src/test/ui/lint/lint-exceeding-bitshifts2.stderr index 8a6d2a89c7063..cb96982a78930 100644 --- a/src/test/ui/lint/lint-exceeding-bitshifts2.stderr +++ b/src/test/ui/lint/lint-exceeding-bitshifts2.stderr @@ -1,23 +1,23 @@ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts2.rs:7:15 + --> $DIR/lint-exceeding-bitshifts2.rs:9:15 | LL | let n = 1u8 << (4+4); | ^^^^^^^^^^^^ | note: lint level defined here - --> $DIR/lint-exceeding-bitshifts2.rs:1:9 + --> $DIR/lint-exceeding-bitshifts2.rs:3:9 | LL | #![deny(exceeding_bitshifts, const_err)] | ^^^^^^^^^^^^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts2.rs:15:15 + --> $DIR/lint-exceeding-bitshifts2.rs:17:15 | LL | let n = 1_isize << BITS; | ^^^^^^^^^^^^^^^ error: attempt to shift left with overflow - --> $DIR/lint-exceeding-bitshifts2.rs:16:15 + --> $DIR/lint-exceeding-bitshifts2.rs:18:15 | LL | let n = 1_usize << BITS; | ^^^^^^^^^^^^^^^