diff options
Diffstat (limited to 'compiler/stable_mir/src/mir/body.rs')
| -rw-r--r-- | compiler/stable_mir/src/mir/body.rs | 622 |
1 files changed, 575 insertions, 47 deletions
diff --git a/compiler/stable_mir/src/mir/body.rs b/compiler/stable_mir/src/mir/body.rs index 069337836..b8fd9370a 100644 --- a/compiler/stable_mir/src/mir/body.rs +++ b/compiler/stable_mir/src/mir/body.rs @@ -1,36 +1,59 @@ -use crate::ty::{AdtDef, ClosureDef, Const, CoroutineDef, GenericArgs, Movability, Region, Ty}; -use crate::Opaque; -use crate::Span; - +use crate::mir::pretty::{function_body, pretty_statement, pretty_terminator}; +use crate::ty::{ + AdtDef, ClosureDef, Const, CoroutineDef, GenericArgs, Movability, Region, RigidTy, Ty, TyKind, + VariantIdx, +}; +use crate::{Error, Opaque, Span, Symbol}; +use std::io; /// The SMIR representation of a single function. #[derive(Clone, Debug)] pub struct Body { pub blocks: Vec<BasicBlock>, - // Declarations of locals within the function. - // - // The first local is the return value pointer, followed by `arg_count` - // locals for the function arguments, followed by any user-declared - // variables and temporaries. + /// Declarations of locals within the function. + /// + /// The first local is the return value pointer, followed by `arg_count` + /// locals for the function arguments, followed by any user-declared + /// variables and temporaries. pub(super) locals: LocalDecls, - // The number of arguments this function takes. + /// The number of arguments this function takes. pub(super) arg_count: usize, + + /// Debug information pertaining to user variables, including captures. + pub var_debug_info: Vec<VarDebugInfo>, + + /// Mark an argument (which must be a tuple) as getting passed as its individual components. + /// + /// This is used for the "rust-call" ABI such as closures. + pub(super) spread_arg: Option<Local>, + + /// The span that covers the entire function body. + pub span: Span, } +pub type BasicBlockIdx = usize; + impl Body { /// Constructs a `Body`. /// /// A constructor is required to build a `Body` from outside the crate /// because the `arg_count` and `locals` fields are private. - pub fn new(blocks: Vec<BasicBlock>, locals: LocalDecls, arg_count: usize) -> Self { + pub fn new( + blocks: Vec<BasicBlock>, + locals: LocalDecls, + arg_count: usize, + var_debug_info: Vec<VarDebugInfo>, + spread_arg: Option<Local>, + span: Span, + ) -> Self { // If locals doesn't contain enough entries, it can lead to panics in // `ret_local`, `arg_locals`, and `inner_locals`. assert!( locals.len() > arg_count, "A Body must contain at least a local for the return value and each of the function's arguments" ); - Self { blocks, locals, arg_count } + Self { blocks, locals, arg_count, var_debug_info, spread_arg, span } } /// Return local that holds this function's return value. @@ -56,6 +79,44 @@ impl Body { pub fn locals(&self) -> &[LocalDecl] { &self.locals } + + /// Get the local declaration for this local. + pub fn local_decl(&self, local: Local) -> Option<&LocalDecl> { + self.locals.get(local) + } + + /// Get an iterator for all local declarations. + pub fn local_decls(&self) -> impl Iterator<Item = (Local, &LocalDecl)> { + self.locals.iter().enumerate() + } + + pub fn dump<W: io::Write>(&self, w: &mut W) -> io::Result<()> { + writeln!(w, "{}", function_body(self))?; + self.blocks + .iter() + .enumerate() + .map(|(index, block)| -> io::Result<()> { + writeln!(w, " bb{}: {{", index)?; + let _ = block + .statements + .iter() + .map(|statement| -> io::Result<()> { + writeln!(w, "{}", pretty_statement(&statement.kind))?; + Ok(()) + }) + .collect::<Vec<_>>(); + pretty_terminator(&block.terminator.kind, w)?; + writeln!(w, "").unwrap(); + writeln!(w, " }}").unwrap(); + Ok(()) + }) + .collect::<Result<Vec<_>, _>>()?; + Ok(()) + } + + pub fn spread_arg(&self) -> Option<Local> { + self.spread_arg + } } type LocalDecls = Vec<LocalDecl>; @@ -64,9 +125,10 @@ type LocalDecls = Vec<LocalDecl>; pub struct LocalDecl { pub ty: Ty, pub span: Span, + pub mutability: Mutability, } -#[derive(Clone, Debug)] +#[derive(Clone, PartialEq, Eq, Debug)] pub struct BasicBlock { pub statements: Vec<Statement>, pub terminator: Terminator, @@ -78,15 +140,22 @@ pub struct Terminator { pub span: Span, } +impl Terminator { + pub fn successors(&self) -> Successors { + self.kind.successors() + } +} + +pub type Successors = Vec<BasicBlockIdx>; + #[derive(Clone, Debug, Eq, PartialEq)] pub enum TerminatorKind { Goto { - target: usize, + target: BasicBlockIdx, }, SwitchInt { discr: Operand, - targets: Vec<SwitchTarget>, - otherwise: usize, + targets: SwitchTargets, }, Resume, Abort, @@ -94,34 +163,81 @@ pub enum TerminatorKind { Unreachable, Drop { place: Place, - target: usize, + target: BasicBlockIdx, unwind: UnwindAction, }, Call { func: Operand, args: Vec<Operand>, destination: Place, - target: Option<usize>, + target: Option<BasicBlockIdx>, unwind: UnwindAction, }, Assert { cond: Operand, expected: bool, msg: AssertMessage, - target: usize, + target: BasicBlockIdx, unwind: UnwindAction, }, - CoroutineDrop, InlineAsm { template: String, operands: Vec<InlineAsmOperand>, options: String, line_spans: String, - destination: Option<usize>, + destination: Option<BasicBlockIdx>, unwind: UnwindAction, }, } +impl TerminatorKind { + pub fn successors(&self) -> Successors { + use self::TerminatorKind::*; + match *self { + Call { target: Some(t), unwind: UnwindAction::Cleanup(u), .. } + | Drop { target: t, unwind: UnwindAction::Cleanup(u), .. } + | Assert { target: t, unwind: UnwindAction::Cleanup(u), .. } + | InlineAsm { destination: Some(t), unwind: UnwindAction::Cleanup(u), .. } => { + vec![t, u] + } + Goto { target: t } + | Call { target: None, unwind: UnwindAction::Cleanup(t), .. } + | Call { target: Some(t), unwind: _, .. } + | Drop { target: t, unwind: _, .. } + | Assert { target: t, unwind: _, .. } + | InlineAsm { destination: None, unwind: UnwindAction::Cleanup(t), .. } + | InlineAsm { destination: Some(t), unwind: _, .. } => { + vec![t] + } + + Return + | Resume + | Abort + | Unreachable + | Call { target: None, unwind: _, .. } + | InlineAsm { destination: None, unwind: _, .. } => { + vec![] + } + SwitchInt { ref targets, .. } => targets.all_targets(), + } + } + + pub fn unwind(&self) -> Option<&UnwindAction> { + match *self { + TerminatorKind::Goto { .. } + | TerminatorKind::Return + | TerminatorKind::Unreachable + | TerminatorKind::Resume + | TerminatorKind::Abort + | TerminatorKind::SwitchInt { .. } => None, + TerminatorKind::Call { ref unwind, .. } + | TerminatorKind::Assert { ref unwind, .. } + | TerminatorKind::Drop { ref unwind, .. } + | TerminatorKind::InlineAsm { ref unwind, .. } => Some(unwind), + } + } +} + #[derive(Clone, Debug, Eq, PartialEq)] pub struct InlineAsmOperand { pub in_value: Option<Operand>, @@ -131,12 +247,12 @@ pub struct InlineAsmOperand { pub raw_rpr: String, } -#[derive(Clone, Debug, Eq, PartialEq)] +#[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum UnwindAction { Continue, Unreachable, Terminate, - Cleanup(usize), + Cleanup(BasicBlockIdx), } #[derive(Clone, Debug, Eq, PartialEq)] @@ -151,7 +267,58 @@ pub enum AssertMessage { MisalignedPointerDereference { required: Operand, found: Operand }, } -#[derive(Clone, Debug, Eq, PartialEq)] +impl AssertMessage { + pub fn description(&self) -> Result<&'static str, Error> { + match self { + AssertMessage::Overflow(BinOp::Add, _, _) => Ok("attempt to add with overflow"), + AssertMessage::Overflow(BinOp::Sub, _, _) => Ok("attempt to subtract with overflow"), + AssertMessage::Overflow(BinOp::Mul, _, _) => Ok("attempt to multiply with overflow"), + AssertMessage::Overflow(BinOp::Div, _, _) => Ok("attempt to divide with overflow"), + AssertMessage::Overflow(BinOp::Rem, _, _) => { + Ok("attempt to calculate the remainder with overflow") + } + AssertMessage::OverflowNeg(_) => Ok("attempt to negate with overflow"), + AssertMessage::Overflow(BinOp::Shr, _, _) => Ok("attempt to shift right with overflow"), + AssertMessage::Overflow(BinOp::Shl, _, _) => Ok("attempt to shift left with overflow"), + AssertMessage::Overflow(op, _, _) => Err(error!("`{:?}` cannot overflow", op)), + AssertMessage::DivisionByZero(_) => Ok("attempt to divide by zero"), + AssertMessage::RemainderByZero(_) => { + Ok("attempt to calculate the remainder with a divisor of zero") + } + AssertMessage::ResumedAfterReturn(CoroutineKind::Coroutine) => { + Ok("coroutine resumed after completion") + } + AssertMessage::ResumedAfterReturn(CoroutineKind::Async(_)) => { + Ok("`async fn` resumed after completion") + } + AssertMessage::ResumedAfterReturn(CoroutineKind::Gen(_)) => { + Ok("`async gen fn` resumed after completion") + } + AssertMessage::ResumedAfterReturn(CoroutineKind::AsyncGen(_)) => { + Ok("`gen fn` should just keep returning `AssertMessage::None` after completion") + } + AssertMessage::ResumedAfterPanic(CoroutineKind::Coroutine) => { + Ok("coroutine resumed after panicking") + } + AssertMessage::ResumedAfterPanic(CoroutineKind::Async(_)) => { + Ok("`async fn` resumed after panicking") + } + AssertMessage::ResumedAfterPanic(CoroutineKind::Gen(_)) => { + Ok("`async gen fn` resumed after panicking") + } + AssertMessage::ResumedAfterPanic(CoroutineKind::AsyncGen(_)) => { + Ok("`gen fn` should just keep returning `AssertMessage::None` after panicking") + } + + AssertMessage::BoundsCheck { .. } => Ok("index out of bounds"), + AssertMessage::MisalignedPointerDereference { .. } => { + Ok("misaligned pointer dereference") + } + } + } +} + +#[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum BinOp { Add, AddUnchecked, @@ -177,7 +344,47 @@ pub enum BinOp { Offset, } -#[derive(Clone, Debug, Eq, PartialEq)] +impl BinOp { + /// Return the type of this operation for the given input Ty. + /// This function does not perform type checking, and it currently doesn't handle SIMD. + pub fn ty(&self, lhs_ty: Ty, rhs_ty: Ty) -> Ty { + match self { + BinOp::Add + | BinOp::AddUnchecked + | BinOp::Sub + | BinOp::SubUnchecked + | BinOp::Mul + | BinOp::MulUnchecked + | BinOp::Div + | BinOp::Rem + | BinOp::BitXor + | BinOp::BitAnd + | BinOp::BitOr => { + assert_eq!(lhs_ty, rhs_ty); + assert!(lhs_ty.kind().is_primitive()); + lhs_ty + } + BinOp::Shl | BinOp::ShlUnchecked | BinOp::Shr | BinOp::ShrUnchecked => { + assert!(lhs_ty.kind().is_primitive()); + assert!(rhs_ty.kind().is_primitive()); + lhs_ty + } + BinOp::Offset => { + assert!(lhs_ty.kind().is_raw_ptr()); + assert!(rhs_ty.kind().is_integral()); + lhs_ty + } + BinOp::Eq | BinOp::Lt | BinOp::Le | BinOp::Ne | BinOp::Ge | BinOp::Gt => { + assert_eq!(lhs_ty, rhs_ty); + let lhs_kind = lhs_ty.kind(); + assert!(lhs_kind.is_primitive() || lhs_kind.is_raw_ptr() || lhs_kind.is_fn_ptr()); + Ty::bool_ty() + } + } + } +} + +#[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum UnOp { Not, Neg, @@ -188,9 +395,10 @@ pub enum CoroutineKind { Async(CoroutineSource), Coroutine, Gen(CoroutineSource), + AsyncGen(CoroutineSource), } -#[derive(Clone, Debug, Eq, PartialEq)] +#[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum CoroutineSource { Block, Closure, @@ -214,7 +422,7 @@ pub enum FakeReadCause { } /// Describes what kind of retag is to be performed -#[derive(Clone, Debug, Eq, PartialEq, Hash)] +#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)] pub enum RetagKind { FnEntry, TwoPhase, @@ -222,7 +430,7 @@ pub enum RetagKind { Default, } -#[derive(Clone, Debug, Eq, PartialEq, Hash)] +#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)] pub enum Variance { Covariant, Invariant, @@ -378,6 +586,63 @@ pub enum Rvalue { Use(Operand), } +impl Rvalue { + pub fn ty(&self, locals: &[LocalDecl]) -> Result<Ty, Error> { + match self { + Rvalue::Use(operand) => operand.ty(locals), + Rvalue::Repeat(operand, count) => { + Ok(Ty::new_array_with_const_len(operand.ty(locals)?, count.clone())) + } + Rvalue::ThreadLocalRef(did) => Ok(did.ty()), + Rvalue::Ref(reg, bk, place) => { + let place_ty = place.ty(locals)?; + Ok(Ty::new_ref(reg.clone(), place_ty, bk.to_mutable_lossy())) + } + Rvalue::AddressOf(mutability, place) => { + let place_ty = place.ty(locals)?; + Ok(Ty::new_ptr(place_ty, *mutability)) + } + Rvalue::Len(..) => Ok(Ty::usize_ty()), + Rvalue::Cast(.., ty) => Ok(*ty), + Rvalue::BinaryOp(op, lhs, rhs) => { + let lhs_ty = lhs.ty(locals)?; + let rhs_ty = rhs.ty(locals)?; + Ok(op.ty(lhs_ty, rhs_ty)) + } + Rvalue::CheckedBinaryOp(op, lhs, rhs) => { + let lhs_ty = lhs.ty(locals)?; + let rhs_ty = rhs.ty(locals)?; + let ty = op.ty(lhs_ty, rhs_ty); + Ok(Ty::new_tuple(&[ty, Ty::bool_ty()])) + } + Rvalue::UnaryOp(UnOp::Not | UnOp::Neg, operand) => operand.ty(locals), + Rvalue::Discriminant(place) => { + let place_ty = place.ty(locals)?; + place_ty + .kind() + .discriminant_ty() + .ok_or_else(|| error!("Expected a `RigidTy` but found: {place_ty:?}")) + } + Rvalue::NullaryOp(NullOp::SizeOf | NullOp::AlignOf | NullOp::OffsetOf(..), _) => { + Ok(Ty::usize_ty()) + } + Rvalue::Aggregate(ak, ops) => match *ak { + AggregateKind::Array(ty) => Ty::try_new_array(ty, ops.len() as u64), + AggregateKind::Tuple => Ok(Ty::new_tuple( + &ops.iter().map(|op| op.ty(locals)).collect::<Result<Vec<_>, _>>()?, + )), + AggregateKind::Adt(def, _, ref args, _, _) => Ok(def.ty_with_args(args)), + AggregateKind::Closure(def, ref args) => Ok(Ty::new_closure(def, args.clone())), + AggregateKind::Coroutine(def, ref args, mov) => { + Ok(Ty::new_coroutine(def, args.clone(), mov)) + } + }, + Rvalue::ShallowInitBox(_, ty) => Ok(Ty::new_box(*ty)), + Rvalue::CopyForDeref(place) => place.ty(locals), + } + } +} + #[derive(Clone, Debug, Eq, PartialEq)] pub enum AggregateKind { Array(Ty), @@ -398,23 +663,188 @@ pub enum Operand { pub struct Place { pub local: Local, /// projection out of a place (access a field, deref a pointer, etc) - pub projection: String, + pub projection: Vec<ProjectionElem>, +} + +impl From<Local> for Place { + fn from(local: Local) -> Self { + Place { local, projection: vec![] } + } +} + +/// Debug information pertaining to a user variable. +#[derive(Clone, Debug, Eq, PartialEq)] +pub struct VarDebugInfo { + /// The variable name. + pub name: Symbol, + + /// Source info of the user variable, including the scope + /// within which the variable is visible (to debuginfo). + pub source_info: SourceInfo, + + /// The user variable's data is split across several fragments, + /// each described by a `VarDebugInfoFragment`. + pub composite: Option<VarDebugInfoFragment>, + + /// Where the data for this user variable is to be found. + pub value: VarDebugInfoContents, + + /// When present, indicates what argument number this variable is in the function that it + /// originated from (starting from 1). Note, if MIR inlining is enabled, then this is the + /// argument number in the original function before it was inlined. + pub argument_index: Option<u16>, +} + +impl VarDebugInfo { + /// Return a local variable if this info is related to one. + pub fn local(&self) -> Option<Local> { + match &self.value { + VarDebugInfoContents::Place(place) if place.projection.is_empty() => Some(place.local), + VarDebugInfoContents::Place(_) | VarDebugInfoContents::Const(_) => None, + } + } + + /// Return a constant if this info is related to one. + pub fn constant(&self) -> Option<&ConstOperand> { + match &self.value { + VarDebugInfoContents::Place(_) => None, + VarDebugInfoContents::Const(const_op) => Some(const_op), + } + } +} + +pub type SourceScope = u32; + +#[derive(Clone, Debug, Eq, PartialEq)] +pub struct SourceInfo { + pub span: Span, + pub scope: SourceScope, +} + +#[derive(Clone, Debug, Eq, PartialEq)] +pub struct VarDebugInfoFragment { + pub ty: Ty, + pub projection: Vec<ProjectionElem>, +} + +#[derive(Clone, Debug, Eq, PartialEq)] +pub enum VarDebugInfoContents { + Place(Place), + Const(ConstOperand), +} + +#[derive(Clone, Debug, Eq, PartialEq)] +pub struct ConstOperand { + pub span: Span, + pub user_ty: Option<UserTypeAnnotationIndex>, + pub const_: Const, +} + +// In MIR ProjectionElem is parameterized on the second Field argument and the Index argument. This +// is so it can be used for both Places (for which the projection elements are of type +// ProjectionElem<Local, Ty>) and user-provided type annotations (for which the projection elements +// are of type ProjectionElem<(), ()>). In SMIR we don't need this generality, so we just use +// ProjectionElem for Places. +#[derive(Clone, Debug, Eq, PartialEq)] +pub enum ProjectionElem { + /// Dereference projections (e.g. `*_1`) project to the address referenced by the base place. + Deref, + + /// A field projection (e.g., `f` in `_1.f`) project to a field in the base place. The field is + /// referenced by source-order index rather than the name of the field. The fields type is also + /// given. + Field(FieldIdx, Ty), + + /// Index into a slice/array. The value of the index is computed at runtime using the `V` + /// argument. + /// + /// Note that this does not also dereference, and so it does not exactly correspond to slice + /// indexing in Rust. In other words, in the below Rust code: + /// + /// ```rust + /// let x = &[1, 2, 3, 4]; + /// let i = 2; + /// x[i]; + /// ``` + /// + /// The `x[i]` is turned into a `Deref` followed by an `Index`, not just an `Index`. The same + /// thing is true of the `ConstantIndex` and `Subslice` projections below. + Index(Local), + + /// Index into a slice/array given by offsets. + /// + /// These indices are generated by slice patterns. Easiest to explain by example: + /// + /// ```ignore (illustrative) + /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false }, + /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false }, + /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true }, + /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true }, + /// ``` + ConstantIndex { + /// index or -index (in Python terms), depending on from_end + offset: u64, + /// The thing being indexed must be at least this long. For arrays this + /// is always the exact length. + min_length: u64, + /// Counting backwards from end? This is always false when indexing an + /// array. + from_end: bool, + }, + + /// Projects a slice from the base place. + /// + /// These indices are generated by slice patterns. If `from_end` is true, this represents + /// `slice[from..slice.len() - to]`. Otherwise it represents `array[from..to]`. + Subslice { + from: u64, + to: u64, + /// Whether `to` counts from the start or end of the array/slice. + from_end: bool, + }, + + /// "Downcast" to a variant of an enum or a coroutine. + Downcast(VariantIdx), + + /// Like an explicit cast from an opaque type to a concrete type, but without + /// requiring an intermediate variable. + OpaqueCast(Ty), + + /// A `Subtype(T)` projection is applied to any `StatementKind::Assign` where + /// type of lvalue doesn't match the type of rvalue, the primary goal is making subtyping + /// explicit during optimizations and codegen. + /// + /// This projection doesn't impact the runtime behavior of the program except for potentially changing + /// some type metadata of the interpreter or codegen backend. + Subtype(Ty), } #[derive(Clone, Debug, Eq, PartialEq)] pub struct UserTypeProjection { pub base: UserTypeAnnotationIndex, - pub projection: String, + + pub projection: Opaque, } pub type Local = usize; pub const RETURN_LOCAL: Local = 0; -type FieldIdx = usize; - -/// The source-order index of a variant in a type. -pub type VariantIdx = usize; +/// The source-order index of a field in a variant. +/// +/// For example, in the following types, +/// ```ignore(illustrative) +/// enum Demo1 { +/// Variant0 { a: bool, b: i32 }, +/// Variant1 { c: u8, d: u64 }, +/// } +/// struct Demo2 { e: u8, f: u16, g: u8 } +/// ``` +/// `a`'s `FieldIdx` is `0`, +/// `b`'s `FieldIdx` is `1`, +/// `c`'s `FieldIdx` is `0`, and +/// `g`'s `FieldIdx` is `2`. +pub type FieldIdx = usize; type UserTypeAnnotationIndex = usize; @@ -425,13 +855,45 @@ pub struct Constant { pub literal: Const, } +/// The possible branch sites of a [TerminatorKind::SwitchInt]. #[derive(Clone, Debug, Eq, PartialEq)] -pub struct SwitchTarget { - pub value: u128, - pub target: usize, +pub struct SwitchTargets { + /// The conditional branches where the first element represents the value that guards this + /// branch, and the second element is the branch target. + branches: Vec<(u128, BasicBlockIdx)>, + /// The `otherwise` branch which will be taken in case none of the conditional branches are + /// satisfied. + otherwise: BasicBlockIdx, } -#[derive(Clone, Debug, Eq, PartialEq)] +impl SwitchTargets { + /// All possible targets including the `otherwise` target. + pub fn all_targets(&self) -> Successors { + self.branches.iter().map(|(_, target)| *target).chain(Some(self.otherwise)).collect() + } + + /// The `otherwise` branch target. + pub fn otherwise(&self) -> BasicBlockIdx { + self.otherwise + } + + /// The conditional targets which are only taken if the pattern matches the given value. + pub fn branches(&self) -> impl Iterator<Item = (u128, BasicBlockIdx)> + '_ { + self.branches.iter().copied() + } + + /// The number of targets including `otherwise`. + pub fn len(&self) -> usize { + self.branches.len() + 1 + } + + /// Create a new SwitchTargets from the given branches and `otherwise` target. + pub fn new(branches: Vec<(u128, BasicBlockIdx)>, otherwise: BasicBlockIdx) -> SwitchTargets { + SwitchTargets { branches, otherwise } + } +} + +#[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum BorrowKind { /// Data must be immutable and is aliasable. Shared, @@ -449,14 +911,25 @@ pub enum BorrowKind { }, } -#[derive(Clone, Debug, Eq, PartialEq)] +impl BorrowKind { + pub fn to_mutable_lossy(self) -> Mutability { + match self { + BorrowKind::Mut { .. } => Mutability::Mut, + BorrowKind::Shared => Mutability::Not, + // FIXME: There's no type corresponding to a shallow borrow, so use `&` as an approximation. + BorrowKind::Fake => Mutability::Not, + } + } +} + +#[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum MutBorrowKind { Default, TwoPhaseBorrow, ClosureCapture, } -#[derive(Clone, Debug, PartialEq, Eq)] +#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)] pub enum Mutability { Not, Mut, @@ -468,7 +941,7 @@ pub enum Safety { Normal, } -#[derive(Clone, Debug, Eq, PartialEq)] +#[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum PointerCoercion { /// Go from a fn-item type to a fn-pointer type. ReifyFnPointer, @@ -495,7 +968,7 @@ pub enum PointerCoercion { Unsize, } -#[derive(Clone, Debug, Eq, PartialEq)] +#[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum CastKind { PointerExposeAddress, PointerFromExposedAddress, @@ -521,10 +994,16 @@ pub enum NullOp { } impl Operand { - pub fn ty(&self, locals: &[LocalDecl]) -> Ty { + /// Get the type of an operand relative to the local declaration. + /// + /// In order to retrieve the correct type, the `locals` argument must match the list of all + /// locals from the function body where this operand originates from. + /// + /// Errors indicate a malformed operand or incompatible locals list. + pub fn ty(&self, locals: &[LocalDecl]) -> Result<Ty, Error> { match self { Operand::Copy(place) | Operand::Move(place) => place.ty(locals), - Operand::Constant(c) => c.ty(), + Operand::Constant(c) => Ok(c.ty()), } } } @@ -536,8 +1015,57 @@ impl Constant { } impl Place { - pub fn ty(&self, locals: &[LocalDecl]) -> Ty { - let _start_ty = locals[self.local].ty; - todo!("Implement projection") + /// Resolve down the chain of projections to get the type referenced at the end of it. + /// E.g.: + /// Calling `ty()` on `var.field` should return the type of `field`. + /// + /// In order to retrieve the correct type, the `locals` argument must match the list of all + /// locals from the function body where this place originates from. + pub fn ty(&self, locals: &[LocalDecl]) -> Result<Ty, Error> { + let start_ty = locals[self.local].ty; + self.projection.iter().fold(Ok(start_ty), |place_ty, elem| { + let ty = place_ty?; + match elem { + ProjectionElem::Deref => Self::deref_ty(ty), + ProjectionElem::Field(_idx, fty) => Ok(*fty), + ProjectionElem::Index(_) | ProjectionElem::ConstantIndex { .. } => { + Self::index_ty(ty) + } + ProjectionElem::Subslice { from, to, from_end } => { + Self::subslice_ty(ty, from, to, from_end) + } + ProjectionElem::Downcast(_) => Ok(ty), + ProjectionElem::OpaqueCast(ty) | ProjectionElem::Subtype(ty) => Ok(*ty), + } + }) + } + + fn index_ty(ty: Ty) -> Result<Ty, Error> { + ty.kind().builtin_index().ok_or_else(|| error!("Cannot index non-array type: {ty:?}")) + } + + fn subslice_ty(ty: Ty, from: &u64, to: &u64, from_end: &bool) -> Result<Ty, Error> { + let ty_kind = ty.kind(); + match ty_kind { + TyKind::RigidTy(RigidTy::Slice(..)) => Ok(ty), + TyKind::RigidTy(RigidTy::Array(inner, _)) if !from_end => Ty::try_new_array( + inner, + to.checked_sub(*from).ok_or_else(|| error!("Subslice overflow: {from}..{to}"))?, + ), + TyKind::RigidTy(RigidTy::Array(inner, size)) => { + let size = size.eval_target_usize()?; + let len = size - from - to; + Ty::try_new_array(inner, len) + } + _ => Err(Error(format!("Cannot subslice non-array type: `{ty_kind:?}`"))), + } + } + + fn deref_ty(ty: Ty) -> Result<Ty, Error> { + let deref_ty = ty + .kind() + .builtin_deref(true) + .ok_or_else(|| error!("Cannot dereference type: {ty:?}"))?; + Ok(deref_ty.ty) } } |