use std::collections::{HashMap, HashSet}; use std::fmt::Write; use rustc::hir::def_id::DefId; use rustc::hir::map::definitions::DefPathData; use rustc::middle::const_val::ConstVal; use rustc::middle::region::CodeExtent; use rustc::mir; use rustc::traits::Reveal; use rustc::ty::layout::{self, Layout, Size, Align, HasDataLayout}; use rustc::ty::subst::{Subst, Substs, Kind}; use rustc::ty::{self, Ty, TyCtxt, TypeFoldable}; use rustc_data_structures::indexed_vec::Idx; use syntax::codemap::{self, DUMMY_SP}; use syntax::ast::Mutability; use syntax::abi::Abi; use super::{EvalError, EvalResult, EvalErrorKind, GlobalId, Lvalue, LvalueExtra, Memory, MemoryPointer, HasMemory, MemoryKind, operator, PrimVal, PrimValKind, Value, Pointer, ValidationQuery, Machine}; pub struct EvalContext<'a, 'tcx: 'a, M: Machine<'tcx>> { /// Stores data required by the `Machine` pub machine_data: M::Data, /// The results of the type checker, from rustc. pub tcx: TyCtxt<'a, 'tcx, 'tcx>, /// The virtual memory system. pub memory: Memory<'a, 'tcx, M>, /// Lvalues that were suspended by the validation subsystem, and will be recovered later pub(crate) suspended: HashMap>>, /// Precomputed statics, constants and promoteds. pub globals: HashMap, PtrAndAlign>, /// The virtual call stack. pub(crate) stack: Vec>, /// The maximum number of stack frames allowed pub(crate) stack_limit: usize, /// The maximum number of operations that may be executed. /// This prevents infinite loops and huge computations from freezing up const eval. /// Remove once halting problem is solved. pub(crate) steps_remaining: u64, } /// A stack frame. pub struct Frame<'tcx> { //////////////////////////////////////////////////////////////////////////////// // Function and callsite information //////////////////////////////////////////////////////////////////////////////// /// The MIR for the function called on this frame. pub mir: &'tcx mir::Mir<'tcx>, /// The def_id and substs of the current function pub instance: ty::Instance<'tcx>, /// The span of the call site. pub span: codemap::Span, //////////////////////////////////////////////////////////////////////////////// // Return lvalue and locals //////////////////////////////////////////////////////////////////////////////// /// The block to return to when returning from the current stack frame pub return_to_block: StackPopCleanup, /// The location where the result of the current stack frame should be written to. pub return_lvalue: Lvalue, /// The list of locals for this stack frame, stored in order as /// `[arguments..., variables..., temporaries...]`. The locals are stored as `Option`s. /// `None` represents a local that is currently dead, while a live local /// can either directly contain `PrimVal` or refer to some part of an `Allocation`. /// /// Before being initialized, arguments are `Value::ByVal(PrimVal::Undef)` and other locals are `None`. pub locals: Vec>, //////////////////////////////////////////////////////////////////////////////// // Current position within the function //////////////////////////////////////////////////////////////////////////////// /// The block that is currently executed (or will be executed after the above call stacks /// return). pub block: mir::BasicBlock, /// The index of the currently evaluated statment. pub stmt: usize, } #[derive(Clone, Debug, Eq, PartialEq, Hash)] pub enum StackPopCleanup { /// The stackframe existed to compute the initial value of a static/constant, make sure it /// isn't modifyable afterwards in case of constants. /// In case of `static mut`, mark the memory to ensure it's never marked as immutable through /// references or deallocated MarkStatic(Mutability), /// A regular stackframe added due to a function call will need to get forwarded to the next /// block Goto(mir::BasicBlock), /// The main function and diverging functions have nowhere to return to None, } #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)] pub struct DynamicLifetime { pub frame: usize, pub region: Option, // "None" indicates "until the function ends" } #[derive(Copy, Clone, Debug)] pub struct ResourceLimits { pub memory_size: u64, pub step_limit: u64, pub stack_limit: usize, } impl Default for ResourceLimits { fn default() -> Self { ResourceLimits { memory_size: 100 * 1024 * 1024, // 100 MB step_limit: 1_000_000, stack_limit: 100, } } } #[derive(Copy, Clone, Debug)] pub struct TyAndPacked<'tcx> { pub ty: Ty<'tcx>, pub packed: bool, } #[derive(Copy, Clone, Debug)] pub struct ValTy<'tcx> { pub value: Value, pub ty: Ty<'tcx>, } impl<'tcx> ::std::ops::Deref for ValTy<'tcx> { type Target = Value; fn deref(&self) -> &Value { &self.value } } #[derive(Copy, Clone, Debug)] pub struct PtrAndAlign { pub ptr: Pointer, /// Remember whether this lvalue is *supposed* to be aligned. pub aligned: bool, } impl PtrAndAlign { pub fn to_ptr<'tcx>(self) -> EvalResult<'tcx, MemoryPointer> { self.ptr.to_ptr() } pub fn offset<'tcx, C: HasDataLayout>(self, i: u64, cx: C) -> EvalResult<'tcx, Self> { Ok(PtrAndAlign { ptr: self.ptr.offset(i, cx)?, aligned: self.aligned, }) } } impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> { pub fn new( tcx: TyCtxt<'a, 'tcx, 'tcx>, limits: ResourceLimits, machine_data: M::Data, memory_data: M::MemoryData, ) -> Self { EvalContext { machine_data, tcx, memory: Memory::new(&tcx.data_layout, limits.memory_size, memory_data), suspended: HashMap::new(), globals: HashMap::new(), stack: Vec::new(), stack_limit: limits.stack_limit, steps_remaining: limits.step_limit, } } pub fn alloc_ptr(&mut self, ty: Ty<'tcx>) -> EvalResult<'tcx, MemoryPointer> { let substs = self.substs(); self.alloc_ptr_with_substs(ty, substs) } pub fn alloc_ptr_with_substs( &mut self, ty: Ty<'tcx>, substs: &'tcx Substs<'tcx>, ) -> EvalResult<'tcx, MemoryPointer> { let size = self.type_size_with_substs(ty, substs)?.expect( "cannot alloc memory for unsized type", ); let align = self.type_align_with_substs(ty, substs)?; self.memory.allocate(size, align, MemoryKind::Stack) } pub fn memory(&self) -> &Memory<'a, 'tcx, M> { &self.memory } pub fn memory_mut(&mut self) -> &mut Memory<'a, 'tcx, M> { &mut self.memory } pub fn stack(&self) -> &[Frame<'tcx>] { &self.stack } #[inline] pub fn cur_frame(&self) -> usize { assert!(self.stack.len() > 0); self.stack.len() - 1 } pub fn str_to_value(&mut self, s: &str) -> EvalResult<'tcx, Value> { let ptr = self.memory.allocate_cached(s.as_bytes())?; Ok(Value::ByValPair( PrimVal::Ptr(ptr), PrimVal::from_u128(s.len() as u128), )) } pub(super) fn const_to_value(&mut self, const_val: &ConstVal<'tcx>) -> EvalResult<'tcx, Value> { use rustc::middle::const_val::ConstVal::*; let primval = match *const_val { Integral(const_int) => PrimVal::Bytes(const_int.to_u128_unchecked()), Float(val) => PrimVal::Bytes(val.bits), Bool(b) => PrimVal::from_bool(b), Char(c) => PrimVal::from_char(c), Str(ref s) => return self.str_to_value(s), ByteStr(ref bs) => { let ptr = self.memory.allocate_cached(bs)?; PrimVal::Ptr(ptr) } Variant(_) => unimplemented!(), Struct(_) => unimplemented!(), Tuple(_) => unimplemented!(), // function items are zero sized and thus have no readable value Function(..) => PrimVal::Undef, Array(_) => unimplemented!(), Repeat(_, _) => unimplemented!(), }; Ok(Value::ByVal(primval)) } pub(super) fn type_is_sized(&self, ty: Ty<'tcx>) -> bool { // generics are weird, don't run this function on a generic assert!(!ty.needs_subst()); ty.is_sized(self.tcx, ty::ParamEnv::empty(Reveal::All), DUMMY_SP) } pub fn load_mir( &self, instance: ty::InstanceDef<'tcx>, ) -> EvalResult<'tcx, &'tcx mir::Mir<'tcx>> { trace!("load mir {:?}", instance); match instance { ty::InstanceDef::Item(def_id) => { self.tcx.maybe_optimized_mir(def_id).ok_or_else(|| { EvalErrorKind::NoMirFor(self.tcx.item_path_str(def_id)).into() }) } _ => Ok(self.tcx.instance_mir(instance)), } } pub fn monomorphize(&self, ty: Ty<'tcx>, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> { // miri doesn't care about lifetimes, and will choke on some crazy ones // let's simply get rid of them let without_lifetimes = self.tcx.erase_regions(&ty); let substituted = without_lifetimes.subst(self.tcx, substs); let substituted = self.tcx.normalize_associated_type(&substituted); substituted } /// Return the size and aligment of the value at the given type. /// Note that the value does not matter if the type is sized. For unsized types, /// the value has to be a fat pointer, and we only care about the "extra" data in it. pub fn size_and_align_of_dst( &mut self, ty: ty::Ty<'tcx>, value: Value, ) -> EvalResult<'tcx, (u64, u64)> { if let Some(size) = self.type_size(ty)? { Ok((size as u64, self.type_align(ty)? as u64)) } else { match ty.sty { ty::TyAdt(..) | ty::TyTuple(..) => { // First get the size of all statically known fields. // Don't use type_of::sizing_type_of because that expects t to be sized, // and it also rounds up to alignment, which we want to avoid, // as the unsized field's alignment could be smaller. assert!(!ty.is_simd()); let layout = self.type_layout(ty)?; debug!("DST {} layout: {:?}", ty, layout); let (sized_size, sized_align) = match *layout { ty::layout::Layout::Univariant { ref variant, .. } => { ( variant.offsets.last().map_or(0, |o| o.bytes()), variant.align, ) } _ => { bug!( "size_and_align_of_dst: expcted Univariant for `{}`, found {:#?}", ty, layout ); } }; debug!( "DST {} statically sized prefix size: {} align: {:?}", ty, sized_size, sized_align ); // Recurse to get the size of the dynamically sized field (must be // the last field). let (unsized_size, unsized_align) = match ty.sty { ty::TyAdt(def, substs) => { let last_field = def.struct_variant().fields.last().unwrap(); let field_ty = self.field_ty(substs, last_field); self.size_and_align_of_dst(field_ty, value)? } ty::TyTuple(ref types, _) => { let field_ty = types.last().unwrap(); let field_ty = self.tcx.normalize_associated_type(field_ty); self.size_and_align_of_dst(field_ty, value)? } _ => bug!("We already checked that we know this type"), }; // FIXME (#26403, #27023): We should be adding padding // to `sized_size` (to accommodate the `unsized_align` // required of the unsized field that follows) before // summing it with `sized_size`. (Note that since #26403 // is unfixed, we do not yet add the necessary padding // here. But this is where the add would go.) // Return the sum of sizes and max of aligns. let size = sized_size + unsized_size; // Choose max of two known alignments (combined value must // be aligned according to more restrictive of the two). let align = sized_align.max(Align::from_bytes(unsized_align, unsized_align).unwrap()); // Issue #27023: must add any necessary padding to `size` // (to make it a multiple of `align`) before returning it. // // Namely, the returned size should be, in C notation: // // `size + ((size & (align-1)) ? align : 0)` // // emulated via the semi-standard fast bit trick: // // `(size + (align-1)) & -align` let size = Size::from_bytes(size).abi_align(align).bytes(); Ok((size, align.abi())) } ty::TyDynamic(..) => { let (_, vtable) = value.into_ptr_vtable_pair(&mut self.memory)?; // the second entry in the vtable is the dynamic size of the object. self.read_size_and_align_from_vtable(vtable) } ty::TySlice(_) | ty::TyStr => { let elem_ty = ty.sequence_element_type(self.tcx); let elem_size = self.type_size(elem_ty)?.expect( "slice element must be sized", ) as u64; let (_, len) = value.into_slice(&mut self.memory)?; let align = self.type_align(elem_ty)?; Ok((len * elem_size, align as u64)) } _ => bug!("size_of_val::<{:?}>", ty), } } } /// Returns the normalized type of a struct field fn field_ty(&self, param_substs: &Substs<'tcx>, f: &ty::FieldDef) -> ty::Ty<'tcx> { self.tcx.normalize_associated_type( &f.ty(self.tcx, param_substs), ) } pub fn type_size(&self, ty: Ty<'tcx>) -> EvalResult<'tcx, Option> { self.type_size_with_substs(ty, self.substs()) } pub fn type_align(&self, ty: Ty<'tcx>) -> EvalResult<'tcx, u64> { self.type_align_with_substs(ty, self.substs()) } pub fn type_size_with_substs( &self, ty: Ty<'tcx>, substs: &'tcx Substs<'tcx>, ) -> EvalResult<'tcx, Option> { let layout = self.type_layout_with_substs(ty, substs)?; if layout.is_unsized() { Ok(None) } else { Ok(Some(layout.size(&self.tcx.data_layout).bytes())) } } pub fn type_align_with_substs( &self, ty: Ty<'tcx>, substs: &'tcx Substs<'tcx>, ) -> EvalResult<'tcx, u64> { self.type_layout_with_substs(ty, substs).map(|layout| { layout.align(&self.tcx.data_layout).abi() }) } pub fn type_layout(&self, ty: Ty<'tcx>) -> EvalResult<'tcx, &'tcx Layout> { self.type_layout_with_substs(ty, self.substs()) } fn type_layout_with_substs( &self, ty: Ty<'tcx>, substs: &'tcx Substs<'tcx>, ) -> EvalResult<'tcx, &'tcx Layout> { // TODO(solson): Is this inefficient? Needs investigation. let ty = self.monomorphize(ty, substs); ty.layout(self.tcx, ty::ParamEnv::empty(Reveal::All)) .map_err(|layout| EvalErrorKind::Layout(layout).into()) } pub fn push_stack_frame( &mut self, instance: ty::Instance<'tcx>, span: codemap::Span, mir: &'tcx mir::Mir<'tcx>, return_lvalue: Lvalue, return_to_block: StackPopCleanup, ) -> EvalResult<'tcx> { ::log_settings::settings().indentation += 1; /// Return the set of locals that have a storage annotation anywhere fn collect_storage_annotations<'tcx>(mir: &'tcx mir::Mir<'tcx>) -> HashSet { use rustc::mir::StatementKind::*; let mut set = HashSet::new(); for block in mir.basic_blocks() { for stmt in block.statements.iter() { match stmt.kind { StorageLive(mir::Lvalue::Local(local)) | StorageDead(mir::Lvalue::Local(local)) => { set.insert(local); } _ => {} } } } set } // Subtract 1 because `local_decls` includes the ReturnMemoryPointer, but we don't store a local // `Value` for that. let num_locals = mir.local_decls.len() - 1; // FIXME: generators produce broken storage annotations (https://github.com/rust-lang/rust/issues/44179) let locals = if mir.generator_layout.is_some() { vec![Some(Value::ByVal(PrimVal::Undef)); num_locals] } else { let annotated_locals = collect_storage_annotations(mir); let mut locals = vec![None; num_locals]; for i in 0..num_locals { let local = mir::Local::new(i + 1); if !annotated_locals.contains(&local) { locals[i] = Some(Value::ByVal(PrimVal::Undef)); } } locals }; self.stack.push(Frame { mir, block: mir::START_BLOCK, return_to_block, return_lvalue, locals, span, instance, stmt: 0, }); let cur_frame = self.cur_frame(); self.memory.set_cur_frame(cur_frame); if self.stack.len() > self.stack_limit { err!(StackFrameLimitReached) } else { Ok(()) } } pub(super) fn pop_stack_frame(&mut self) -> EvalResult<'tcx> { ::log_settings::settings().indentation -= 1; self.memory.locks_lifetime_ended(None); let frame = self.stack.pop().expect( "tried to pop a stack frame, but there were none", ); if !self.stack.is_empty() { // TODO: IS this the correct time to start considering these accesses as originating from the returned-to stack frame? let cur_frame = self.cur_frame(); self.memory.set_cur_frame(cur_frame); } match frame.return_to_block { StackPopCleanup::MarkStatic(mutable) => { if let Lvalue::Ptr { ptr, .. } = frame.return_lvalue { // FIXME: to_ptr()? might be too extreme here, static zsts might reach this under certain conditions self.memory.mark_static_initalized( ptr.to_ptr()?.alloc_id, mutable, )? } else { bug!("StackPopCleanup::MarkStatic on: {:?}", frame.return_lvalue); } } StackPopCleanup::Goto(target) => self.goto_block(target), StackPopCleanup::None => {} } // deallocate all locals that are backed by an allocation for local in frame.locals { self.deallocate_local(local)?; } Ok(()) } pub fn deallocate_local(&mut self, local: Option) -> EvalResult<'tcx> { if let Some(Value::ByRef(ptr)) = local { trace!("deallocating local"); let ptr = ptr.to_ptr()?; self.memory.dump_alloc(ptr.alloc_id); match self.memory.get(ptr.alloc_id)?.kind { // for a constant like `const FOO: &i32 = &1;` the local containing // the `1` is referred to by the global. We transitively marked everything // the global refers to as static itself, so we don't free it here MemoryKind::Static => {} MemoryKind::Stack => self.memory.deallocate(ptr, None, MemoryKind::Stack)?, other => bug!("local contained non-stack memory: {:?}", other), } }; Ok(()) } pub fn assign_discr_and_fields( &mut self, dest: Lvalue, dest_ty: Ty<'tcx>, discr_offset: u64, operands: &[mir::Operand<'tcx>], discr_val: u128, variant_idx: usize, discr_size: u64, discr_signed: bool, ) -> EvalResult<'tcx> { // FIXME(solson) let dest_ptr = self.force_allocation(dest)?.to_ptr()?; let discr_dest = dest_ptr.offset(discr_offset, &self)?; self.memory.write_primval(discr_dest, PrimVal::Bytes(discr_val), discr_size, discr_signed)?; let dest = Lvalue::Ptr { ptr: PtrAndAlign { ptr: dest_ptr.into(), aligned: true, }, extra: LvalueExtra::DowncastVariant(variant_idx), }; self.assign_fields(dest, dest_ty, operands) } pub fn assign_fields( &mut self, dest: Lvalue, dest_ty: Ty<'tcx>, operands: &[mir::Operand<'tcx>], ) -> EvalResult<'tcx> { if self.type_size(dest_ty)? == Some(0) { // zst assigning is a nop return Ok(()); } if self.ty_to_primval_kind(dest_ty).is_ok() { assert_eq!(operands.len(), 1); let value = self.eval_operand(&operands[0])?; return self.write_value(value, dest); } for (field_index, operand) in operands.iter().enumerate() { let value = self.eval_operand(operand)?; let field_dest = self.lvalue_field(dest, field_index, dest_ty, value.ty)?; self.write_value(value, field_dest)?; } Ok(()) } /// Evaluate an assignment statement. /// /// 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 lvalue. pub(super) fn eval_rvalue_into_lvalue( &mut self, rvalue: &mir::Rvalue<'tcx>, lvalue: &mir::Lvalue<'tcx>, ) -> EvalResult<'tcx> { let dest = self.eval_lvalue(lvalue)?; let dest_ty = self.lvalue_ty(lvalue); let dest_layout = self.type_layout(dest_ty)?; use rustc::mir::Rvalue::*; match *rvalue { Use(ref operand) => { let value = self.eval_operand(operand)?.value; let valty = ValTy { value, ty: dest_ty, }; self.write_value(valty, dest)?; } BinaryOp(bin_op, ref left, ref right) => { let left = self.eval_operand(left)?; let right = self.eval_operand(right)?; if self.intrinsic_overflowing( bin_op, left, right, dest, dest_ty, )? { // There was an overflow in an unchecked binop. Right now, we consider this an error and bail out. // The rationale is that the reason rustc emits unchecked binops in release mode (vs. the checked binops // it emits in debug mode) is performance, but it doesn't cost us any performance in miri. // If, however, the compiler ever starts transforming unchecked intrinsics into unchecked binops, // we have to go back to just ignoring the overflow here. return err!(OverflowingMath); } } CheckedBinaryOp(bin_op, ref left, ref right) => { let left = self.eval_operand(left)?; let right = self.eval_operand(right)?; self.intrinsic_with_overflow( bin_op, left, right, dest, dest_ty, )?; } UnaryOp(un_op, ref operand) => { let val = self.eval_operand_to_primval(operand)?; let kind = self.ty_to_primval_kind(dest_ty)?; self.write_primval( dest, operator::unary_op(un_op, val, kind)?, dest_ty, )?; } // Skip everything for zsts Aggregate(..) if self.type_size(dest_ty)? == Some(0) => {} Aggregate(ref kind, ref operands) => { self.inc_step_counter_and_check_limit(operands.len() as u64)?; use rustc::ty::layout::Layout::*; match *dest_layout { Univariant { ref variant, .. } => { self.write_maybe_aligned_mut(!variant.packed, |ecx| { ecx.assign_fields(dest, dest_ty, operands) })?; } Array { .. } => { self.assign_fields(dest, dest_ty, operands)?; } General { discr, ref variants, .. } => { if let mir::AggregateKind::Adt(adt_def, variant, _, _) = **kind { let discr_val = adt_def .discriminants(self.tcx) .nth(variant) .expect("broken mir: Adt variant id invalid") .to_u128_unchecked(); let discr_size = discr.size().bytes(); self.assign_discr_and_fields( dest, dest_ty, variants[variant].offsets[0].bytes(), operands, discr_val, variant, discr_size, false, )?; } else { bug!("tried to assign {:?} to Layout::General", kind); } } RawNullablePointer { nndiscr, .. } => { if let mir::AggregateKind::Adt(_, variant, _, _) = **kind { if nndiscr == variant as u64 { assert_eq!(operands.len(), 1); let operand = &operands[0]; let value = self.eval_operand(operand)?; self.write_value(value, dest)?; } else { if let Some(operand) = operands.get(0) { assert_eq!(operands.len(), 1); let operand_ty = self.operand_ty(operand); assert_eq!(self.type_size(operand_ty)?, Some(0)); } self.write_null(dest, dest_ty)?; } } else { bug!("tried to assign {:?} to Layout::RawNullablePointer", kind); } } StructWrappedNullablePointer { nndiscr, ref discrfield_source, ref nonnull, .. } => { if let mir::AggregateKind::Adt(_, variant, _, _) = **kind { if nndiscr == variant as u64 { self.write_maybe_aligned_mut(!nonnull.packed, |ecx| { ecx.assign_fields(dest, dest_ty, operands) })?; } else { for operand in operands { let operand_ty = self.operand_ty(operand); assert_eq!(self.type_size(operand_ty)?, Some(0)); } self.write_struct_wrapped_null_pointer( dest_ty, nndiscr, discrfield_source, dest, )?; } } else { bug!("tried to assign {:?} to Layout::RawNullablePointer", kind); } } CEnum { .. } => { assert_eq!(operands.len(), 0); if let mir::AggregateKind::Adt(adt_def, variant, _, _) = **kind { let n = adt_def .discriminants(self.tcx) .nth(variant) .expect("broken mir: Adt variant index invalid") .to_u128_unchecked(); self.write_primval(dest, PrimVal::Bytes(n), dest_ty)?; } else { bug!("tried to assign {:?} to Layout::CEnum", kind); } } Vector { count, .. } => { debug_assert_eq!(count, operands.len() as u64); self.assign_fields(dest, dest_ty, operands)?; } UntaggedUnion { ref variants } => { assert_eq!(operands.len(), 1); let operand = &operands[0]; let value = self.eval_operand(operand)?; self.write_maybe_aligned_mut(!variants.packed, |ecx| { ecx.write_value(value, dest) })?; } _ => { return err!(Unimplemented(format!( "can't handle destination layout {:?} when assigning {:?}", dest_layout, kind ))); } } } Repeat(ref operand, _) => { let (elem_ty, length) = match dest_ty.sty { ty::TyArray(elem_ty, n) => (elem_ty, n as u64), _ => { bug!( "tried to assign array-repeat to non-array type {:?}", dest_ty ) } }; self.inc_step_counter_and_check_limit(length)?; let elem_size = self.type_size(elem_ty)?.expect( "repeat element type must be sized", ); let value = self.eval_operand(operand)?.value; // FIXME(solson) let dest = Pointer::from(self.force_allocation(dest)?.to_ptr()?); for i in 0..length { let elem_dest = dest.offset(i * elem_size, &self)?; self.write_value_to_ptr(value, elem_dest, elem_ty)?; } } Len(ref lvalue) => { // FIXME(CTFE): don't allow computing the length of arrays in const eval let src = self.eval_lvalue(lvalue)?; let ty = self.lvalue_ty(lvalue); let (_, len) = src.elem_ty_and_len(ty); self.write_primval( dest, PrimVal::from_u128(len as u128), dest_ty, )?; } Ref(_, _, ref lvalue) => { let src = self.eval_lvalue(lvalue)?; // We ignore the alignment of the lvalue here -- special handling for packed structs ends // at the `&` operator. let (ptr, extra) = self.force_allocation(src)?.to_ptr_extra_aligned(); let val = match extra { LvalueExtra::None => ptr.ptr.to_value(), LvalueExtra::Length(len) => ptr.ptr.to_value_with_len(len), LvalueExtra::Vtable(vtable) => ptr.ptr.to_value_with_vtable(vtable), LvalueExtra::DowncastVariant(..) => { bug!("attempted to take a reference to an enum downcast lvalue") } }; let valty = ValTy { value: val, ty: dest_ty, }; self.write_value(valty, dest)?; } NullaryOp(mir::NullOp::Box, ty) => { let ptr = M::box_alloc(self, ty)?; self.write_primval(dest, ptr, dest_ty)?; } NullaryOp(mir::NullOp::SizeOf, ty) => { let size = self.type_size(ty)?.expect( "SizeOf nullary MIR operator called for unsized type", ); self.write_primval( dest, PrimVal::from_u128(size as u128), dest_ty, )?; } Cast(kind, ref operand, cast_ty) => { debug_assert_eq!(self.monomorphize(cast_ty, self.substs()), dest_ty); use rustc::mir::CastKind::*; match kind { Unsize => { let src = self.eval_operand(operand)?; self.unsize_into(src.value, src.ty, dest, dest_ty)?; } Misc => { let src = self.eval_operand(operand)?; if self.type_is_fat_ptr(src.ty) { match (src.value, self.type_is_fat_ptr(dest_ty)) { (Value::ByRef { .. }, _) | (Value::ByValPair(..), true) => { let valty = ValTy { value: src.value, ty: dest_ty, }; self.write_value(valty, dest)?; } (Value::ByValPair(data, _), false) => { let valty = ValTy { value: Value::ByVal(data), ty: dest_ty, }; self.write_value(valty, dest)?; } (Value::ByVal(_), _) => bug!("expected fat ptr"), } } else { let src_val = self.value_to_primval(src)?; let dest_val = self.cast_primval(src_val, src.ty, dest_ty)?; let valty = ValTy { value: Value::ByVal(dest_val), ty: dest_ty, }; self.write_value(valty, dest)?; } } ReifyFnPointer => { match self.operand_ty(operand).sty { ty::TyFnDef(def_id, substs) => { let instance = resolve(self.tcx, def_id, substs); let fn_ptr = self.memory.create_fn_alloc(instance); let valty = ValTy { value: Value::ByVal(PrimVal::Ptr(fn_ptr)), ty: dest_ty, }; self.write_value(valty, dest)?; } ref other => bug!("reify fn pointer on {:?}", other), } } UnsafeFnPointer => { match dest_ty.sty { ty::TyFnPtr(_) => { let mut src = self.eval_operand(operand)?; src.ty = dest_ty; self.write_value(src, dest)?; } ref other => bug!("fn to unsafe fn cast on {:?}", other), } } ClosureFnPointer => { match self.operand_ty(operand).sty { ty::TyClosure(def_id, substs) => { let instance = resolve_closure( self.tcx, def_id, substs, ty::ClosureKind::FnOnce, ); let fn_ptr = self.memory.create_fn_alloc(instance); let valty = ValTy { value: Value::ByVal(PrimVal::Ptr(fn_ptr)), ty: dest_ty, }; self.write_value(valty, dest)?; } ref other => bug!("closure fn pointer on {:?}", other), } } } } Discriminant(ref lvalue) => { let lval = self.eval_lvalue(lvalue)?; let ty = self.lvalue_ty(lvalue); let ptr = self.force_allocation(lval)?.to_ptr()?; let discr_val = self.read_discriminant_value(ptr, ty)?; if let ty::TyAdt(adt_def, _) = ty.sty { trace!("Read discriminant {}, valid discriminants {:?}", discr_val, adt_def.discriminants(self.tcx).collect::>()); if adt_def.discriminants(self.tcx).all(|v| { discr_val != v.to_u128_unchecked() }) { return err!(InvalidDiscriminant); } self.write_primval(dest, PrimVal::Bytes(discr_val), dest_ty)?; } else { bug!("rustc only generates Rvalue::Discriminant for enums"); } } } if log_enabled!(::log::LogLevel::Trace) { self.dump_local(dest); } Ok(()) } pub(crate) fn write_struct_wrapped_null_pointer( &mut self, dest_ty: ty::Ty<'tcx>, nndiscr: u64, discrfield_source: &layout::FieldPath, dest: Lvalue, ) -> EvalResult<'tcx> { let (offset, TyAndPacked { ty, packed }) = self.nonnull_offset_and_ty( dest_ty, nndiscr, discrfield_source, )?; let nonnull = self.force_allocation(dest)?.to_ptr()?.offset( offset.bytes(), &self, )?; trace!("struct wrapped nullable pointer type: {}", ty); // only the pointer part of a fat pointer is used for this space optimization let discr_size = self.type_size(ty)?.expect( "bad StructWrappedNullablePointer discrfield", ); self.memory.write_maybe_aligned_mut(!packed, |mem| { // We're writing 0, signedness does not matter mem.write_primval(nonnull, PrimVal::Bytes(0), discr_size, false) }) } pub(super) fn type_is_fat_ptr(&self, ty: Ty<'tcx>) -> bool { match ty.sty { ty::TyRawPtr(ref tam) | ty::TyRef(_, ref tam) => !self.type_is_sized(tam.ty), ty::TyAdt(def, _) if def.is_box() => !self.type_is_sized(ty.boxed_ty()), _ => false, } } pub(super) fn nonnull_offset_and_ty( &self, ty: Ty<'tcx>, nndiscr: u64, discrfield: &[u32], ) -> EvalResult<'tcx, (Size, TyAndPacked<'tcx>)> { // Skip the constant 0 at the start meant for LLVM GEP and the outer non-null variant let path = discrfield.iter().skip(2).map(|&i| i as usize); // Handle the field index for the outer non-null variant. let (inner_offset, inner_ty) = match ty.sty { ty::TyAdt(adt_def, substs) => { let variant = &adt_def.variants[nndiscr as usize]; let index = discrfield[1]; let field = &variant.fields[index as usize]; ( self.get_field_offset(ty, index as usize)?, field.ty(self.tcx, substs), ) } _ => bug!("non-enum for StructWrappedNullablePointer: {}", ty), }; self.field_path_offset_and_ty(inner_offset, inner_ty, path) } fn field_path_offset_and_ty>( &self, mut offset: Size, mut ty: Ty<'tcx>, path: I, ) -> EvalResult<'tcx, (Size, TyAndPacked<'tcx>)> { // Skip the initial 0 intended for LLVM GEP. let mut packed = false; for field_index in path { let field_offset = self.get_field_offset(ty, field_index)?; trace!( "field_path_offset_and_ty: {}, {}, {:?}, {:?}", field_index, ty, field_offset, offset ); let field_ty = self.get_field_ty(ty, field_index)?; ty = field_ty.ty; packed = packed || field_ty.packed; offset = offset .checked_add(field_offset, &self.tcx.data_layout) .unwrap(); } Ok((offset, TyAndPacked { ty, packed })) } fn get_fat_field( &self, pointee_ty: Ty<'tcx>, field_index: usize, ) -> EvalResult<'tcx, Ty<'tcx>> { match (field_index, &self.tcx.struct_tail(pointee_ty).sty) { (1, &ty::TyStr) | (1, &ty::TySlice(_)) => Ok(self.tcx.types.usize), (1, &ty::TyDynamic(..)) | (0, _) => Ok(self.tcx.mk_imm_ptr(self.tcx.types.u8)), _ => bug!("invalid fat pointee type: {}", pointee_ty), } } /// Returns the field type and whether the field is packed pub fn get_field_ty( &self, ty: Ty<'tcx>, field_index: usize, ) -> EvalResult<'tcx, TyAndPacked<'tcx>> { match ty.sty { ty::TyAdt(adt_def, _) if adt_def.is_box() => Ok(TyAndPacked { ty: self.get_fat_field(ty.boxed_ty(), field_index)?, packed: false, }), ty::TyAdt(adt_def, substs) if adt_def.is_enum() => { use rustc::ty::layout::Layout::*; match *self.type_layout(ty)? { RawNullablePointer { nndiscr, .. } => Ok(TyAndPacked { ty: adt_def.variants[nndiscr as usize].fields[field_index].ty( self.tcx, substs, ), packed: false, }), StructWrappedNullablePointer { nndiscr, ref nonnull, .. } => { let ty = adt_def.variants[nndiscr as usize].fields[field_index].ty( self.tcx, substs, ); Ok(TyAndPacked { ty, packed: nonnull.packed, }) } // mir optimizations treat single variant enums as structs General { .. } if adt_def.variants.len() == 1 => Ok(TyAndPacked { ty: adt_def.variants[0].fields[field_index].ty(self.tcx, substs), packed: false, }), _ => { err!(Unimplemented(format!( "get_field_ty can't handle enum type: {:?}, {:?}", ty, ty.sty ))) } } } ty::TyAdt(adt_def, substs) => { let variant_def = adt_def.struct_variant(); use rustc::ty::layout::Layout::*; match *self.type_layout(ty)? { UntaggedUnion { ref variants } => Ok(TyAndPacked { ty: variant_def.fields[field_index].ty(self.tcx, substs), packed: variants.packed, }), Univariant { ref variant, .. } => Ok(TyAndPacked { ty: variant_def.fields[field_index].ty(self.tcx, substs), packed: variant.packed, }), _ => { err!(Unimplemented(format!( "get_field_ty can't handle struct type: {:?}, {:?}", ty, ty.sty ))) } } } ty::TyTuple(fields, _) => Ok(TyAndPacked { ty: fields[field_index], packed: false, }), ty::TyRef(_, ref tam) | ty::TyRawPtr(ref tam) => Ok(TyAndPacked { ty: self.get_fat_field(tam.ty, field_index)?, packed: false, }), ty::TyArray(ref inner, _) => Ok(TyAndPacked { ty: inner, packed: false, }), ty::TyClosure(def_id, ref closure_substs) => Ok(TyAndPacked { ty: closure_substs.upvar_tys(def_id, self.tcx).nth(field_index).unwrap(), packed: false, }), _ => { err!(Unimplemented( format!("can't handle type: {:?}, {:?}", ty, ty.sty), )) } } } fn get_field_offset(&self, ty: Ty<'tcx>, field_index: usize) -> EvalResult<'tcx, Size> { // Also see lvalue_field in lvalue.rs, which handles more cases but needs an actual value at the given type let layout = self.type_layout(ty)?; use rustc::ty::layout::Layout::*; match *layout { Univariant { ref variant, .. } => Ok(variant.offsets[field_index]), FatPointer { .. } => { let bytes = field_index as u64 * self.memory.pointer_size(); Ok(Size::from_bytes(bytes)) } StructWrappedNullablePointer { ref nonnull, .. } => Ok(nonnull.offsets[field_index]), UntaggedUnion { .. } => Ok(Size::from_bytes(0)), // mir optimizations treat single variant enums as structs General { ref variants, .. } if variants.len() == 1 => Ok(variants[0].offsets[field_index]), _ => { let msg = format!( "get_field_offset: can't handle type: {:?}, with layout: {:?}", ty, layout ); err!(Unimplemented(msg)) } } } pub fn get_field_count(&self, ty: Ty<'tcx>) -> EvalResult<'tcx, u64> { let layout = self.type_layout(ty)?; use rustc::ty::layout::Layout::*; match *layout { Univariant { ref variant, .. } => Ok(variant.offsets.len() as u64), FatPointer { .. } => Ok(2), StructWrappedNullablePointer { ref nonnull, .. } => Ok(nonnull.offsets.len() as u64), Vector { count, .. } | Array { count, .. } => Ok(count), Scalar { .. } => Ok(0), UntaggedUnion { .. } => Ok(1), _ => { let msg = format!( "get_field_count: can't handle type: {:?}, with layout: {:?}", ty, layout ); err!(Unimplemented(msg)) } } } pub(super) fn eval_operand_to_primval( &mut self, op: &mir::Operand<'tcx>, ) -> EvalResult<'tcx, PrimVal> { let valty = self.eval_operand(op)?; self.value_to_primval(valty) } pub(crate) fn operands_to_args( &mut self, ops: &[mir::Operand<'tcx>], ) -> EvalResult<'tcx, Vec>> { ops.into_iter() .map(|op| self.eval_operand(op)) .collect() } pub fn eval_operand(&mut self, op: &mir::Operand<'tcx>) -> EvalResult<'tcx, ValTy<'tcx>> { use rustc::mir::Operand::*; match *op { Consume(ref lvalue) => { Ok(ValTy { value: self.eval_and_read_lvalue(lvalue)?, ty: self.operand_ty(op), }) }, Constant(ref constant) => { use rustc::mir::Literal; let mir::Constant { ref literal, .. } = **constant; let value = match *literal { Literal::Value { ref value } => self.const_to_value(value)?, Literal::Item { def_id, substs } => { let instance = self.resolve_associated_const(def_id, substs); let cid = GlobalId { instance, promoted: None, }; Value::ByRef(*self.globals.get(&cid).expect("static/const not cached")) } Literal::Promoted { index } => { let cid = GlobalId { instance: self.frame().instance, promoted: Some(index), }; Value::ByRef(*self.globals.get(&cid).expect("promoted not cached")) } }; Ok(ValTy { value, ty: self.operand_ty(op), }) } } } pub fn read_discriminant_value( &self, adt_ptr: MemoryPointer, adt_ty: Ty<'tcx>, ) -> EvalResult<'tcx, u128> { use rustc::ty::layout::Layout::*; let adt_layout = self.type_layout(adt_ty)?; //trace!("read_discriminant_value {:#?}", adt_layout); let discr_val = match *adt_layout { General { discr, .. } => { let discr_size = discr.size().bytes(); self.memory.read_primval(adt_ptr, discr_size, false)?.to_bytes()? } CEnum { discr, signed, .. } => { let discr_size = discr.size().bytes(); self.memory.read_primval(adt_ptr, discr_size, signed)?.to_bytes()? } RawNullablePointer { nndiscr, value } => { let discr_size = value.size(&self.tcx.data_layout).bytes(); trace!("rawnullablepointer with size {}", discr_size); self.read_nonnull_discriminant_value( adt_ptr, nndiscr as u128, discr_size, )? } StructWrappedNullablePointer { nndiscr, ref discrfield_source, .. } => { let (offset, TyAndPacked { ty, packed }) = self.nonnull_offset_and_ty( adt_ty, nndiscr, discrfield_source, )?; let nonnull = adt_ptr.offset(offset.bytes(), &*self)?; trace!("struct wrapped nullable pointer type: {}", ty); // only the pointer part of a fat pointer is used for this space optimization let discr_size = self.type_size(ty)?.expect( "bad StructWrappedNullablePointer discrfield", ); self.read_maybe_aligned(!packed, |ectx| { ectx.read_nonnull_discriminant_value(nonnull, nndiscr as u128, discr_size) })? } // The discriminant_value intrinsic returns 0 for non-sum types. Array { .. } | FatPointer { .. } | Scalar { .. } | Univariant { .. } | Vector { .. } | UntaggedUnion { .. } => 0, }; Ok(discr_val) } fn read_nonnull_discriminant_value( &self, ptr: MemoryPointer, nndiscr: u128, discr_size: u64, ) -> EvalResult<'tcx, u128> { trace!( "read_nonnull_discriminant_value: {:?}, {}, {}", ptr, nndiscr, discr_size ); // We are only interested in 0 vs. non-0, the sign does not matter for this let null = match self.memory.read_primval(ptr, discr_size, false)? { PrimVal::Bytes(0) => true, PrimVal::Bytes(_) | PrimVal::Ptr(..) => false, PrimVal::Undef => return err!(ReadUndefBytes), }; assert!(nndiscr == 0 || nndiscr == 1); Ok(if !null { nndiscr } else { 1 - nndiscr }) } pub fn read_global_as_value(&self, gid: GlobalId) -> Value { Value::ByRef(*self.globals.get(&gid).expect("global not cached")) } pub fn operand_ty(&self, operand: &mir::Operand<'tcx>) -> Ty<'tcx> { self.monomorphize(operand.ty(self.mir(), self.tcx), self.substs()) } fn copy(&mut self, src: Pointer, dest: Pointer, ty: Ty<'tcx>) -> EvalResult<'tcx> { let size = self.type_size(ty)?.expect( "cannot copy from an unsized type", ); let align = self.type_align(ty)?; self.memory.copy(src, dest, size, align, false)?; Ok(()) } pub fn is_packed(&self, ty: Ty<'tcx>) -> EvalResult<'tcx, bool> { let layout = self.type_layout(ty)?; use rustc::ty::layout::Layout::*; Ok(match *layout { Univariant { ref variant, .. } => variant.packed, StructWrappedNullablePointer { ref nonnull, .. } => nonnull.packed, UntaggedUnion { ref variants } => variants.packed, // can only apply #[repr(packed)] to struct and union _ => false, }) } pub fn force_allocation(&mut self, lvalue: Lvalue) -> EvalResult<'tcx, Lvalue> { let new_lvalue = match lvalue { Lvalue::Local { frame, local } => { // -1 since we don't store the return value match self.stack[frame].locals[local.index() - 1] { None => return err!(DeadLocal), Some(Value::ByRef(ptr)) => { Lvalue::Ptr { ptr, extra: LvalueExtra::None, } } Some(val) => { let ty = self.stack[frame].mir.local_decls[local].ty; let ty = self.monomorphize(ty, self.stack[frame].instance.substs); let substs = self.stack[frame].instance.substs; let ptr = self.alloc_ptr_with_substs(ty, substs)?; self.stack[frame].locals[local.index() - 1] = Some(Value::by_ref(ptr.into())); // it stays live self.write_value_to_ptr(val, ptr.into(), ty)?; Lvalue::from_ptr(ptr) } } } Lvalue::Ptr { .. } => lvalue, }; Ok(new_lvalue) } /// ensures this Value is not a ByRef pub(super) fn follow_by_ref_value( &mut self, value: Value, ty: Ty<'tcx>, ) -> EvalResult<'tcx, Value> { match value { Value::ByRef(PtrAndAlign { ptr, aligned }) => { self.read_maybe_aligned(aligned, |ectx| ectx.read_value(ptr, ty)) } other => Ok(other), } } pub fn value_to_primval( &mut self, ValTy { value, ty } : ValTy<'tcx>, ) -> EvalResult<'tcx, PrimVal> { match self.follow_by_ref_value(value, ty)? { Value::ByRef { .. } => bug!("follow_by_ref_value can't result in `ByRef`"), Value::ByVal(primval) => { self.ensure_valid_value(primval, ty)?; Ok(primval) } Value::ByValPair(..) => bug!("value_to_primval can't work with fat pointers"), } } pub fn write_null(&mut self, dest: Lvalue, dest_ty: Ty<'tcx>) -> EvalResult<'tcx> { self.write_primval(dest, PrimVal::Bytes(0), dest_ty) } pub fn write_ptr(&mut self, dest: Lvalue, val: Pointer, dest_ty: Ty<'tcx>) -> EvalResult<'tcx> { let valty = ValTy { value: val.to_value(), ty: dest_ty, }; self.write_value(valty, dest) } pub fn write_primval( &mut self, dest: Lvalue, val: PrimVal, dest_ty: Ty<'tcx>, ) -> EvalResult<'tcx> { let valty = ValTy { value: Value::ByVal(val), ty: dest_ty, }; self.write_value(valty, dest) } pub fn write_value( &mut self, ValTy { value: src_val, ty: dest_ty } : ValTy<'tcx>, dest: Lvalue, ) -> EvalResult<'tcx> { //trace!("Writing {:?} to {:?} at type {:?}", src_val, dest, dest_ty); // Note that it is really important that the type here is the right one, and matches the type things are read at. // In case `src_val` is a `ByValPair`, we don't do any magic here to handle padding properly, which is only // correct if we never look at this data with the wrong type. match dest { Lvalue::Ptr { ptr: PtrAndAlign { ptr, aligned }, extra, } => { assert_eq!(extra, LvalueExtra::None); self.write_maybe_aligned_mut( aligned, |ectx| ectx.write_value_to_ptr(src_val, ptr, dest_ty), ) } Lvalue::Local { frame, local } => { let dest = self.stack[frame].get_local(local)?; self.write_value_possibly_by_val( src_val, |this, val| this.stack[frame].set_local(local, val), dest, dest_ty, ) } } } // The cases here can be a bit subtle. Read carefully! fn write_value_possibly_by_val EvalResult<'tcx>>( &mut self, src_val: Value, write_dest: F, old_dest_val: Value, dest_ty: Ty<'tcx>, ) -> EvalResult<'tcx> { if let Value::ByRef(PtrAndAlign { ptr: dest_ptr, aligned, }) = old_dest_val { // If the value is already `ByRef` (that is, backed by an `Allocation`), // then we must write the new value into this allocation, because there may be // other pointers into the allocation. These other pointers are logically // pointers into the local variable, and must be able to observe the change. // // Thus, it would be an error to replace the `ByRef` with a `ByVal`, unless we // knew for certain that there were no outstanding pointers to this allocation. self.write_maybe_aligned_mut(aligned, |ectx| { ectx.write_value_to_ptr(src_val, dest_ptr, dest_ty) })?; } else if let Value::ByRef(PtrAndAlign { ptr: src_ptr, aligned, }) = src_val { // If the value is not `ByRef`, then we know there are no pointers to it // and we can simply overwrite the `Value` in the locals array directly. // // In this specific case, where the source value is `ByRef`, we must duplicate // the allocation, because this is a by-value operation. It would be incorrect // if they referred to the same allocation, since then a change to one would // implicitly change the other. // // It is a valid optimization to attempt reading a primitive value out of the // source and write that into the destination without making an allocation, so // we do so here. self.read_maybe_aligned_mut(aligned, |ectx| { if let Ok(Some(src_val)) = ectx.try_read_value(src_ptr, dest_ty) { write_dest(ectx, src_val)?; } else { let dest_ptr = ectx.alloc_ptr(dest_ty)?.into(); ectx.copy(src_ptr, dest_ptr, dest_ty)?; write_dest(ectx, Value::by_ref(dest_ptr))?; } Ok(()) })?; } else { // Finally, we have the simple case where neither source nor destination are // `ByRef`. We may simply copy the source value over the the destintion. write_dest(self, src_val)?; } Ok(()) } pub fn write_value_to_ptr( &mut self, value: Value, dest: Pointer, dest_ty: Ty<'tcx>, ) -> EvalResult<'tcx> { match value { Value::ByRef(PtrAndAlign { ptr, aligned }) => { self.read_maybe_aligned_mut(aligned, |ectx| ectx.copy(ptr, dest, dest_ty)) } Value::ByVal(primval) => { let size = self.type_size(dest_ty)?.expect("dest type must be sized"); if size == 0 { assert!(primval.is_undef()); Ok(()) } else { // TODO: Do we need signedness? self.memory.write_primval(dest.to_ptr()?, primval, size, false) } } Value::ByValPair(a, b) => self.write_pair_to_ptr(a, b, dest.to_ptr()?, dest_ty), } } pub fn write_pair_to_ptr( &mut self, a: PrimVal, b: PrimVal, ptr: MemoryPointer, mut ty: Ty<'tcx>, ) -> EvalResult<'tcx> { let mut packed = false; while self.get_field_count(ty)? == 1 { let field = self.get_field_ty(ty, 0)?; ty = field.ty; packed = packed || field.packed; } assert_eq!(self.get_field_count(ty)?, 2); let field_0 = self.get_field_offset(ty, 0)?; let field_1 = self.get_field_offset(ty, 1)?; let field_0_ty = self.get_field_ty(ty, 0)?; let field_1_ty = self.get_field_ty(ty, 1)?; assert_eq!( field_0_ty.packed, field_1_ty.packed, "the two fields must agree on being packed" ); packed = packed || field_0_ty.packed; let field_0_size = self.type_size(field_0_ty.ty)?.expect( "pair element type must be sized", ); let field_1_size = self.type_size(field_1_ty.ty)?.expect( "pair element type must be sized", ); let field_0_ptr = ptr.offset(field_0.bytes(), &self)?.into(); let field_1_ptr = ptr.offset(field_1.bytes(), &self)?.into(); // TODO: What about signedess? self.write_maybe_aligned_mut(!packed, |ectx| { ectx.memory.write_primval(field_0_ptr, a, field_0_size, false) })?; self.write_maybe_aligned_mut(!packed, |ectx| { ectx.memory.write_primval(field_1_ptr, b, field_1_size, false) })?; Ok(()) } pub fn ty_to_primval_kind(&self, ty: Ty<'tcx>) -> EvalResult<'tcx, PrimValKind> { use syntax::ast::FloatTy; let kind = match ty.sty { ty::TyBool => PrimValKind::Bool, ty::TyChar => PrimValKind::Char, ty::TyInt(int_ty) => { use syntax::ast::IntTy::*; let size = match int_ty { I8 => 1, I16 => 2, I32 => 4, I64 => 8, I128 => 16, Is => self.memory.pointer_size(), }; PrimValKind::from_int_size(size) } ty::TyUint(uint_ty) => { use syntax::ast::UintTy::*; let size = match uint_ty { U8 => 1, U16 => 2, U32 => 4, U64 => 8, U128 => 16, Us => self.memory.pointer_size(), }; PrimValKind::from_uint_size(size) } ty::TyFloat(FloatTy::F32) => PrimValKind::F32, ty::TyFloat(FloatTy::F64) => PrimValKind::F64, ty::TyFnPtr(_) => PrimValKind::FnPtr, ty::TyRef(_, ref tam) | ty::TyRawPtr(ref tam) if self.type_is_sized(tam.ty) => PrimValKind::Ptr, ty::TyAdt(def, _) if def.is_box() => PrimValKind::Ptr, ty::TyAdt(def, substs) => { use rustc::ty::layout::Layout::*; match *self.type_layout(ty)? { CEnum { discr, signed, .. } => { let size = discr.size().bytes(); if signed { PrimValKind::from_int_size(size) } else { PrimValKind::from_uint_size(size) } } RawNullablePointer { value, .. } => { use rustc::ty::layout::Primitive::*; match value { // TODO(solson): Does signedness matter here? What should the sign be? Int(int) => PrimValKind::from_uint_size(int.size().bytes()), F32 => PrimValKind::F32, F64 => PrimValKind::F64, Pointer => PrimValKind::Ptr, } } // represent single field structs as their single field Univariant { .. } => { // enums with just one variant are no different, but `.struct_variant()` doesn't work for enums let variant = &def.variants[0]; // FIXME: also allow structs with only a single non zst field if variant.fields.len() == 1 { return self.ty_to_primval_kind(variant.fields[0].ty(self.tcx, substs)); } else { return err!(TypeNotPrimitive(ty)); } } _ => return err!(TypeNotPrimitive(ty)), } } _ => return err!(TypeNotPrimitive(ty)), }; Ok(kind) } fn ensure_valid_value(&self, val: PrimVal, ty: Ty<'tcx>) -> EvalResult<'tcx> { match ty.sty { ty::TyBool if val.to_bytes()? > 1 => err!(InvalidBool), ty::TyChar if ::std::char::from_u32(val.to_bytes()? as u32).is_none() => { err!(InvalidChar(val.to_bytes()? as u32 as u128)) } _ => Ok(()), } } pub fn read_value(&self, ptr: Pointer, ty: Ty<'tcx>) -> EvalResult<'tcx, Value> { if let Some(val) = self.try_read_value(ptr, ty)? { Ok(val) } else { bug!("primitive read failed for type: {:?}", ty); } } pub(crate) fn read_ptr( &self, ptr: MemoryPointer, pointee_ty: Ty<'tcx>, ) -> EvalResult<'tcx, Value> { let ptr_size = self.memory.pointer_size(); let p : Pointer = self.memory.read_ptr_sized_unsigned(ptr)?.into(); if self.type_is_sized(pointee_ty) { Ok(p.to_value()) } else { trace!("reading fat pointer extra of type {}", pointee_ty); let extra = ptr.offset(ptr_size, self)?; match self.tcx.struct_tail(pointee_ty).sty { ty::TyDynamic(..) => Ok(p.to_value_with_vtable( self.memory.read_ptr_sized_unsigned(extra)?.to_ptr()?, )), ty::TySlice(..) | ty::TyStr => Ok( p.to_value_with_len(self.memory.read_ptr_sized_unsigned(extra)?.to_bytes()? as u64), ), _ => bug!("unsized primval ptr read from {:?}", pointee_ty), } } } fn try_read_value(&self, ptr: Pointer, ty: Ty<'tcx>) -> EvalResult<'tcx, Option> { use syntax::ast::FloatTy; let ptr = ptr.to_ptr()?; let val = match ty.sty { ty::TyBool => { let val = self.memory.read_primval(ptr, 1, false)?; let val = match val { PrimVal::Bytes(0) => false, PrimVal::Bytes(1) => true, _ => return err!(InvalidBool), }; PrimVal::from_bool(val) } ty::TyChar => { let c = self.memory.read_primval(ptr, 4, false)?.to_bytes()? as u32; match ::std::char::from_u32(c) { Some(ch) => PrimVal::from_char(ch), None => return err!(InvalidChar(c as u128)), } } ty::TyInt(int_ty) => { use syntax::ast::IntTy::*; let size = match int_ty { I8 => 1, I16 => 2, I32 => 4, I64 => 8, I128 => 16, Is => self.memory.pointer_size(), }; self.memory.read_primval(ptr, size, true)? } ty::TyUint(uint_ty) => { use syntax::ast::UintTy::*; let size = match uint_ty { U8 => 1, U16 => 2, U32 => 4, U64 => 8, U128 => 16, Us => self.memory.pointer_size(), }; self.memory.read_primval(ptr, size, false)? } ty::TyFloat(FloatTy::F32) => PrimVal::Bytes(self.memory.read_primval(ptr, 4, false)?.to_bytes()?), ty::TyFloat(FloatTy::F64) => PrimVal::Bytes(self.memory.read_primval(ptr, 8, false)?.to_bytes()?), ty::TyFnPtr(_) => self.memory.read_ptr_sized_unsigned(ptr)?, ty::TyRef(_, ref tam) | ty::TyRawPtr(ref tam) => return self.read_ptr(ptr, tam.ty).map(Some), ty::TyAdt(def, _) => { if def.is_box() { return self.read_ptr(ptr, ty.boxed_ty()).map(Some); } use rustc::ty::layout::Layout::*; if let CEnum { discr, signed, .. } = *self.type_layout(ty)? { let size = discr.size().bytes(); self.memory.read_primval(ptr, size, signed)? } else { return Ok(None); } } _ => return Ok(None), }; Ok(Some(Value::ByVal(val))) } pub fn frame(&self) -> &Frame<'tcx> { self.stack.last().expect("no call frames exist") } pub(super) fn frame_mut(&mut self) -> &mut Frame<'tcx> { self.stack.last_mut().expect("no call frames exist") } pub(super) fn mir(&self) -> &'tcx mir::Mir<'tcx> { self.frame().mir } pub(super) fn substs(&self) -> &'tcx Substs<'tcx> { self.frame().instance.substs } fn unsize_into_ptr( &mut self, src: Value, src_ty: Ty<'tcx>, dest: Lvalue, dest_ty: Ty<'tcx>, sty: Ty<'tcx>, dty: Ty<'tcx>, ) -> EvalResult<'tcx> { // A -> A conversion let (src_pointee_ty, dest_pointee_ty) = self.tcx.struct_lockstep_tails(sty, dty); match (&src_pointee_ty.sty, &dest_pointee_ty.sty) { (&ty::TyArray(_, length), &ty::TySlice(_)) => { let ptr = src.into_ptr(&self.memory)?; // u64 cast is from usize to u64, which is always good let valty = ValTy { value: ptr.to_value_with_len(length as u64), ty: dest_ty, }; self.write_value(valty, dest) } (&ty::TyDynamic(..), &ty::TyDynamic(..)) => { // For now, upcasts are limited to changes in marker // traits, and hence never actually require an actual // change to the vtable. let valty = ValTy { value: src, ty: dest_ty, }; self.write_value(valty, dest) } (_, &ty::TyDynamic(ref data, _)) => { let trait_ref = data.principal().unwrap().with_self_ty( self.tcx, src_pointee_ty, ); let trait_ref = self.tcx.erase_regions(&trait_ref); let vtable = self.get_vtable(src_pointee_ty, trait_ref)?; let ptr = src.into_ptr(&self.memory)?; let valty = ValTy { value: ptr.to_value_with_vtable(vtable), ty: dest_ty, }; self.write_value(valty, dest) } _ => bug!("invalid unsizing {:?} -> {:?}", src_ty, dest_ty), } } fn unsize_into( &mut self, src: Value, src_ty: Ty<'tcx>, dest: Lvalue, dest_ty: Ty<'tcx>, ) -> EvalResult<'tcx> { match (&src_ty.sty, &dest_ty.sty) { (&ty::TyRef(_, ref s), &ty::TyRef(_, ref d)) | (&ty::TyRef(_, ref s), &ty::TyRawPtr(ref d)) | (&ty::TyRawPtr(ref s), &ty::TyRawPtr(ref d)) => { self.unsize_into_ptr(src, src_ty, dest, dest_ty, s.ty, d.ty) } (&ty::TyAdt(def_a, substs_a), &ty::TyAdt(def_b, substs_b)) => { if def_a.is_box() || def_b.is_box() { if !def_a.is_box() || !def_b.is_box() { panic!("invalid unsizing between {:?} -> {:?}", src_ty, dest_ty); } return self.unsize_into_ptr( src, src_ty, dest, dest_ty, src_ty.boxed_ty(), dest_ty.boxed_ty(), ); } if self.ty_to_primval_kind(src_ty).is_ok() { // TODO: We ignore the packed flag here let sty = self.get_field_ty(src_ty, 0)?.ty; let dty = self.get_field_ty(dest_ty, 0)?.ty; return self.unsize_into(src, sty, dest, dty); } // unsizing of generic struct with pointer fields // Example: `Arc` -> `Arc` // here we need to increase the size of every &T thin ptr field to a fat ptr assert_eq!(def_a, def_b); let src_fields = def_a.variants[0].fields.iter(); let dst_fields = def_b.variants[0].fields.iter(); //let src = adt::MaybeSizedValue::sized(src); //let dst = adt::MaybeSizedValue::sized(dst); let src_ptr = match src { Value::ByRef(PtrAndAlign { ptr, aligned: true }) => ptr, // TODO: Is it possible for unaligned pointers to occur here? _ => bug!("expected aligned pointer, got {:?}", src), }; // FIXME(solson) let dest = self.force_allocation(dest)?.to_ptr()?; let iter = src_fields.zip(dst_fields).enumerate(); for (i, (src_f, dst_f)) in iter { let src_fty = self.field_ty(substs_a, src_f); let dst_fty = self.field_ty(substs_b, dst_f); if self.type_size(dst_fty)? == Some(0) { continue; } let src_field_offset = self.get_field_offset(src_ty, i)?.bytes(); let dst_field_offset = self.get_field_offset(dest_ty, i)?.bytes(); let src_f_ptr = src_ptr.offset(src_field_offset, &self)?; let dst_f_ptr = dest.offset(dst_field_offset, &self)?; if src_fty == dst_fty { self.copy(src_f_ptr, dst_f_ptr.into(), src_fty)?; } else { self.unsize_into( Value::by_ref(src_f_ptr), src_fty, Lvalue::from_ptr(dst_f_ptr), dst_fty, )?; } } Ok(()) } _ => { bug!( "unsize_into: invalid conversion: {:?} -> {:?}", src_ty, dest_ty ) } } } pub fn dump_local(&self, lvalue: Lvalue) { // Debug output match lvalue { Lvalue::Local { frame, local } => { let mut allocs = Vec::new(); let mut msg = format!("{:?}", local); if frame != self.cur_frame() { write!(msg, " ({} frames up)", self.cur_frame() - frame).unwrap(); } write!(msg, ":").unwrap(); match self.stack[frame].get_local(local) { Err(EvalError { kind: EvalErrorKind::DeadLocal, .. }) => { write!(msg, " is dead").unwrap(); } Err(err) => { panic!("Failed to access local: {:?}", err); } Ok(Value::ByRef(PtrAndAlign { ptr, aligned })) => { match ptr.into_inner_primval() { PrimVal::Ptr(ptr) => { write!(msg, " by {}ref:", if aligned { "" } else { "unaligned " }) .unwrap(); allocs.push(ptr.alloc_id); } ptr => write!(msg, " integral by ref: {:?}", ptr).unwrap(), } } Ok(Value::ByVal(val)) => { write!(msg, " {:?}", val).unwrap(); if let PrimVal::Ptr(ptr) = val { allocs.push(ptr.alloc_id); } } Ok(Value::ByValPair(val1, val2)) => { write!(msg, " ({:?}, {:?})", val1, val2).unwrap(); if let PrimVal::Ptr(ptr) = val1 { allocs.push(ptr.alloc_id); } if let PrimVal::Ptr(ptr) = val2 { allocs.push(ptr.alloc_id); } } } trace!("{}", msg); self.memory.dump_allocs(allocs); } Lvalue::Ptr { ptr: PtrAndAlign { ptr, aligned }, .. } => { match ptr.into_inner_primval() { PrimVal::Ptr(ptr) => { trace!("by {}ref:", if aligned { "" } else { "unaligned " }); self.memory.dump_alloc(ptr.alloc_id); } ptr => trace!(" integral by ref: {:?}", ptr), } } } } /// Convenience function to ensure correct usage of locals pub fn modify_local(&mut self, frame: usize, local: mir::Local, f: F) -> EvalResult<'tcx> where F: FnOnce(&mut Self, Value) -> EvalResult<'tcx, Value>, { let val = self.stack[frame].get_local(local)?; let new_val = f(self, val)?; self.stack[frame].set_local(local, new_val)?; // FIXME(solson): Run this when setting to Undef? (See previous version of this code.) // if let Value::ByRef(ptr) = self.stack[frame].get_local(local) { // self.memory.deallocate(ptr)?; // } Ok(()) } pub fn report(&self, e: &mut EvalError) { if let Some(ref mut backtrace) = e.backtrace { let mut trace_text = "\n\nAn error occurred in miri:\n".to_string(); let mut skip_init = true; backtrace.resolve(); 'frames: for (i, frame) in backtrace.frames().iter().enumerate() { for symbol in frame.symbols() { if let Some(name) = symbol.name() { // unmangle the symbol via `to_string` let name = name.to_string(); if name.starts_with("miri::after_analysis") { // don't report initialization gibberish break 'frames; } else if name.starts_with("backtrace::capture::Backtrace::new") // debug mode produces funky symbol names || name.starts_with("backtrace::capture::{{impl}}::new") { // don't report backtrace internals skip_init = false; continue 'frames; } } } if skip_init { continue; } for symbol in frame.symbols() { write!(trace_text, "{}: ", i).unwrap(); if let Some(name) = symbol.name() { write!(trace_text, "{}\n", name).unwrap(); } else { write!(trace_text, "\n").unwrap(); } write!(trace_text, "\tat ").unwrap(); if let Some(file_path) = symbol.filename() { write!(trace_text, "{}", file_path.display()).unwrap(); } else { write!(trace_text, "").unwrap(); } if let Some(line) = symbol.lineno() { write!(trace_text, ":{}\n", line).unwrap(); } else { write!(trace_text, "\n").unwrap(); } } } error!("{}", trace_text); } if let Some(frame) = self.stack().last() { let block = &frame.mir.basic_blocks()[frame.block]; let span = if frame.stmt < block.statements.len() { block.statements[frame.stmt].source_info.span } else { block.terminator().source_info.span }; let mut err = self.tcx.sess.struct_span_err(span, &e.to_string()); for &Frame { instance, span, .. } in self.stack().iter().rev() { if self.tcx.def_key(instance.def_id()).disambiguated_data.data == DefPathData::ClosureExpr { err.span_note(span, "inside call to closure"); continue; } err.span_note(span, &format!("inside call to {}", instance)); } err.emit(); } else { self.tcx.sess.err(&e.to_string()); } } } impl<'tcx> Frame<'tcx> { pub fn get_local(&self, local: mir::Local) -> EvalResult<'tcx, Value> { // Subtract 1 because we don't store a value for the ReturnPointer, the local with index 0. self.locals[local.index() - 1].ok_or(EvalErrorKind::DeadLocal.into()) } fn set_local(&mut self, local: mir::Local, value: Value) -> EvalResult<'tcx> { // Subtract 1 because we don't store a value for the ReturnPointer, the local with index 0. match self.locals[local.index() - 1] { None => err!(DeadLocal), Some(ref mut local) => { *local = value; Ok(()) } } } pub fn storage_live(&mut self, local: mir::Local) -> EvalResult<'tcx, Option> { trace!("{:?} is now live", local); let old = self.locals[local.index() - 1]; self.locals[local.index() - 1] = Some(Value::ByVal(PrimVal::Undef)); // StorageLive *always* kills the value that's currently stored return Ok(old); } /// Returns the old value of the local pub fn storage_dead(&mut self, local: mir::Local) -> EvalResult<'tcx, Option> { trace!("{:?} is now dead", local); let old = self.locals[local.index() - 1]; self.locals[local.index() - 1] = None; return Ok(old); } } // TODO(solson): Upstream these methods into rustc::ty::layout. pub(super) trait IntegerExt { fn size(self) -> Size; } impl IntegerExt for layout::Integer { fn size(self) -> Size { use rustc::ty::layout::Integer::*; match self { I1 | I8 => Size::from_bits(8), I16 => Size::from_bits(16), I32 => Size::from_bits(32), I64 => Size::from_bits(64), I128 => Size::from_bits(128), } } } pub fn is_inhabited<'a, 'tcx: 'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> bool { ty.uninhabited_from(&mut HashMap::default(), tcx).is_empty() } /// FIXME: expose trans::monomorphize::resolve_closure pub fn resolve_closure<'a, 'tcx>( tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId, substs: ty::ClosureSubsts<'tcx>, requested_kind: ty::ClosureKind, ) -> ty::Instance<'tcx> { let actual_kind = tcx.closure_kind(def_id); match needs_fn_once_adapter_shim(actual_kind, requested_kind) { Ok(true) => fn_once_adapter_instance(tcx, def_id, substs), _ => ty::Instance::new(def_id, substs.substs), } } fn fn_once_adapter_instance<'a, 'tcx>( tcx: TyCtxt<'a, 'tcx, 'tcx>, closure_did: DefId, substs: ty::ClosureSubsts<'tcx>, ) -> ty::Instance<'tcx> { debug!("fn_once_adapter_shim({:?}, {:?})", closure_did, substs); let fn_once = tcx.lang_items.fn_once_trait().unwrap(); let call_once = tcx.associated_items(fn_once) .find(|it| it.kind == ty::AssociatedKind::Method) .unwrap() .def_id; let def = ty::InstanceDef::ClosureOnceShim { call_once }; let self_ty = tcx.mk_closure_from_closure_substs(closure_did, substs); let sig = tcx.fn_sig(closure_did).subst(tcx, substs.substs); let sig = tcx.erase_late_bound_regions_and_normalize(&sig); assert_eq!(sig.inputs().len(), 1); let substs = tcx.mk_substs( [Kind::from(self_ty), Kind::from(sig.inputs()[0])] .iter() .cloned(), ); debug!("fn_once_adapter_shim: self_ty={:?} sig={:?}", self_ty, sig); ty::Instance { def, substs } } fn needs_fn_once_adapter_shim( actual_closure_kind: ty::ClosureKind, trait_closure_kind: ty::ClosureKind, ) -> Result { match (actual_closure_kind, trait_closure_kind) { (ty::ClosureKind::Fn, ty::ClosureKind::Fn) | (ty::ClosureKind::FnMut, ty::ClosureKind::FnMut) | (ty::ClosureKind::FnOnce, ty::ClosureKind::FnOnce) => { // No adapter needed. Ok(false) } (ty::ClosureKind::Fn, ty::ClosureKind::FnMut) => { // The closure fn `llfn` is a `fn(&self, ...)`. We want a // `fn(&mut self, ...)`. In fact, at trans time, these are // basically the same thing, so we can just return llfn. Ok(false) } (ty::ClosureKind::Fn, ty::ClosureKind::FnOnce) | (ty::ClosureKind::FnMut, ty::ClosureKind::FnOnce) => { // The closure fn `llfn` is a `fn(&self, ...)` or `fn(&mut // self, ...)`. We want a `fn(self, ...)`. We can produce // this by doing something like: // // fn call_once(self, ...) { call_mut(&self, ...) } // fn call_once(mut self, ...) { call_mut(&mut self, ...) } // // These are both the same at trans time. Ok(true) } _ => Err(()), } } /// The point where linking happens. Resolve a (def_id, substs) /// pair to an instance. pub fn resolve<'a, 'tcx>( tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId, substs: &'tcx Substs<'tcx>, ) -> ty::Instance<'tcx> { debug!("resolve(def_id={:?}, substs={:?})", def_id, substs); let result = if let Some(trait_def_id) = tcx.trait_of_item(def_id) { debug!(" => associated item, attempting to find impl"); let item = tcx.associated_item(def_id); resolve_associated_item(tcx, &item, trait_def_id, substs) } else { let item_type = def_ty(tcx, def_id, substs); let def = match item_type.sty { ty::TyFnDef(..) if { let f = item_type.fn_sig(tcx); f.abi() == Abi::RustIntrinsic || f.abi() == Abi::PlatformIntrinsic } => { debug!(" => intrinsic"); ty::InstanceDef::Intrinsic(def_id) } _ => { if Some(def_id) == tcx.lang_items.drop_in_place_fn() { let ty = substs.type_at(0); if needs_drop_glue(tcx, ty) { debug!(" => nontrivial drop glue"); ty::InstanceDef::DropGlue(def_id, Some(ty)) } else { debug!(" => trivial drop glue"); ty::InstanceDef::DropGlue(def_id, None) } } else { debug!(" => free item"); ty::InstanceDef::Item(def_id) } } }; ty::Instance { def, substs } }; debug!( "resolve(def_id={:?}, substs={:?}) = {}", def_id, substs, result ); result } pub fn needs_drop_glue<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, t: Ty<'tcx>) -> bool { assert!(t.is_normalized_for_trans()); let t = tcx.erase_regions(&t); // FIXME (#22815): note that type_needs_drop conservatively // approximates in some cases and may say a type expression // requires drop glue when it actually does not. // // (In this case it is not clear whether any harm is done, i.e. // erroneously returning `true` in some cases where we could have // returned `false` does not appear unsound. The impact on // code quality is unknown at this time.) let env = ty::ParamEnv::empty(Reveal::All); if !t.needs_drop(tcx, env) { return false; } match t.sty { ty::TyAdt(def, _) if def.is_box() => { let typ = t.boxed_ty(); if !typ.needs_drop(tcx, env) && type_is_sized(tcx, typ) { let layout = t.layout(tcx, ty::ParamEnv::empty(Reveal::All)).unwrap(); // `Box` does not allocate. layout.size(&tcx.data_layout).bytes() != 0 } else { true } } _ => true, } } fn resolve_associated_item<'a, 'tcx>( tcx: TyCtxt<'a, 'tcx, 'tcx>, trait_item: &ty::AssociatedItem, trait_id: DefId, rcvr_substs: &'tcx Substs<'tcx>, ) -> ty::Instance<'tcx> { let def_id = trait_item.def_id; debug!( "resolve_associated_item(trait_item={:?}, \ trait_id={:?}, \ rcvr_substs={:?})", def_id, trait_id, rcvr_substs ); let trait_ref = ty::TraitRef::from_method(tcx, trait_id, rcvr_substs); let vtbl = tcx.trans_fulfill_obligation(DUMMY_SP, ty::Binder(trait_ref)); // Now that we know which impl is being used, we can dispatch to // the actual function: match vtbl { ::rustc::traits::VtableImpl(impl_data) => { let (def_id, substs) = ::rustc::traits::find_associated_item(tcx, trait_item, rcvr_substs, &impl_data); let substs = tcx.erase_regions(&substs); ty::Instance::new(def_id, substs) } ::rustc::traits::VtableGenerator(closure_data) => { ty::Instance { def: ty::InstanceDef::Item(closure_data.closure_def_id), substs: closure_data.substs.substs } } ::rustc::traits::VtableClosure(closure_data) => { let trait_closure_kind = tcx.lang_items.fn_trait_kind(trait_id).unwrap(); resolve_closure( tcx, closure_data.closure_def_id, closure_data.substs, trait_closure_kind, ) } ::rustc::traits::VtableFnPointer(ref data) => { ty::Instance { def: ty::InstanceDef::FnPtrShim(trait_item.def_id, data.fn_ty), substs: rcvr_substs, } } ::rustc::traits::VtableObject(ref data) => { let index = tcx.get_vtable_index_of_object_method(data, def_id); ty::Instance { def: ty::InstanceDef::Virtual(def_id, index), substs: rcvr_substs, } } ::rustc::traits::VtableBuiltin(..) if Some(trait_id) == tcx.lang_items.clone_trait() => { ty::Instance { def: ty::InstanceDef::CloneShim(def_id, trait_ref.self_ty()), substs: rcvr_substs } } _ => bug!("static call to invalid vtable: {:?}", vtbl), } } pub fn def_ty<'a, 'tcx>( tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId, substs: &'tcx Substs<'tcx>, ) -> Ty<'tcx> { let ty = tcx.type_of(def_id); apply_param_substs(tcx, substs, &ty) } /// Monomorphizes a type from the AST by first applying the in-scope /// substitutions and then normalizing any associated types. pub fn apply_param_substs<'a, 'tcx, T>( tcx: TyCtxt<'a, 'tcx, 'tcx>, param_substs: &Substs<'tcx>, value: &T, ) -> T where T: ::rustc::infer::TransNormalize<'tcx>, { debug!( "apply_param_substs(param_substs={:?}, value={:?})", param_substs, value ); let substituted = value.subst(tcx, param_substs); let substituted = tcx.erase_regions(&substituted); AssociatedTypeNormalizer { tcx }.fold(&substituted) } struct AssociatedTypeNormalizer<'a, 'tcx: 'a> { tcx: TyCtxt<'a, 'tcx, 'tcx>, } impl<'a, 'tcx> AssociatedTypeNormalizer<'a, 'tcx> { fn fold>(&mut self, value: &T) -> T { if !value.has_projection_types() { value.clone() } else { value.fold_with(self) } } } impl<'a, 'tcx> ::rustc::ty::fold::TypeFolder<'tcx, 'tcx> for AssociatedTypeNormalizer<'a, 'tcx> { fn tcx<'c>(&'c self) -> TyCtxt<'c, 'tcx, 'tcx> { self.tcx } fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { if !ty.has_projection_types() { ty } else { self.tcx.normalize_associated_type(&ty) } } } fn type_is_sized<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> bool { // generics are weird, don't run this function on a generic assert!(!ty.needs_subst()); ty.is_sized(tcx, ty::ParamEnv::empty(Reveal::All), DUMMY_SP) } pub fn resolve_drop_in_place<'a, 'tcx>( tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>, ) -> ty::Instance<'tcx> { let def_id = tcx.require_lang_item(::rustc::middle::lang_items::DropInPlaceFnLangItem); let substs = tcx.intern_substs(&[Kind::from(ty)]); resolve(tcx, def_id, substs) }