diff options
Diffstat (limited to 'compiler/stable_mir/src/mir')
| -rw-r--r-- | compiler/stable_mir/src/mir/body.rs | 184 | ||||
| -rw-r--r-- | compiler/stable_mir/src/mir/mono.rs | 102 | ||||
| -rw-r--r-- | compiler/stable_mir/src/mir/visit.rs | 414 |
3 files changed, 656 insertions, 44 deletions
diff --git a/compiler/stable_mir/src/mir/body.rs b/compiler/stable_mir/src/mir/body.rs index f93a1a3a9..069337836 100644 --- a/compiler/stable_mir/src/mir/body.rs +++ b/compiler/stable_mir/src/mir/body.rs @@ -1,11 +1,69 @@ -use crate::ty::{AdtDef, ClosureDef, Const, GeneratorDef, GenericArgs, Movability, Region}; +use crate::ty::{AdtDef, ClosureDef, Const, CoroutineDef, GenericArgs, Movability, Region, Ty}; use crate::Opaque; -use crate::{ty::Ty, Span}; +use crate::Span; +/// The SMIR representation of a single function. #[derive(Clone, Debug)] pub struct Body { pub blocks: Vec<BasicBlock>, - pub locals: Vec<Ty>, + + // 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. + pub(super) arg_count: 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 { + // 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 } + } + + /// Return local that holds this function's return value. + pub fn ret_local(&self) -> &LocalDecl { + &self.locals[RETURN_LOCAL] + } + + /// Locals in `self` that correspond to this function's arguments. + pub fn arg_locals(&self) -> &[LocalDecl] { + &self.locals[1..][..self.arg_count] + } + + /// Inner locals for this function. These are the locals that are + /// neither the return local nor the argument locals. + pub fn inner_locals(&self) -> &[LocalDecl] { + &self.locals[self.arg_count + 1..] + } + + /// Convenience function to get all the locals in this function. + /// + /// Locals are typically accessed via the more specific methods `ret_local`, + /// `arg_locals`, and `inner_locals`. + pub fn locals(&self) -> &[LocalDecl] { + &self.locals + } +} + +type LocalDecls = Vec<LocalDecl>; + +#[derive(Clone, Debug, Eq, PartialEq)] +pub struct LocalDecl { + pub ty: Ty, + pub span: Span, } #[derive(Clone, Debug)] @@ -14,8 +72,14 @@ pub struct BasicBlock { pub terminator: Terminator, } -#[derive(Clone, Debug)] -pub enum Terminator { +#[derive(Clone, Debug, Eq, PartialEq)] +pub struct Terminator { + pub kind: TerminatorKind, + pub span: Span, +} + +#[derive(Clone, Debug, Eq, PartialEq)] +pub enum TerminatorKind { Goto { target: usize, }, @@ -47,7 +111,7 @@ pub enum Terminator { target: usize, unwind: UnwindAction, }, - GeneratorDrop, + CoroutineDrop, InlineAsm { template: String, operands: Vec<InlineAsmOperand>, @@ -58,7 +122,7 @@ pub enum Terminator { }, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub struct InlineAsmOperand { pub in_value: Option<Operand>, pub out_place: Option<Place>, @@ -67,7 +131,7 @@ pub struct InlineAsmOperand { pub raw_rpr: String, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum UnwindAction { Continue, Unreachable, @@ -75,19 +139,19 @@ pub enum UnwindAction { Cleanup(usize), } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum AssertMessage { BoundsCheck { len: Operand, index: Operand }, Overflow(BinOp, Operand, Operand), OverflowNeg(Operand), DivisionByZero(Operand), RemainderByZero(Operand), - ResumedAfterReturn(GeneratorKind), - ResumedAfterPanic(GeneratorKind), + ResumedAfterReturn(CoroutineKind), + ResumedAfterPanic(CoroutineKind), MisalignedPointerDereference { required: Operand, found: Operand }, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum BinOp { Add, AddUnchecked, @@ -113,20 +177,21 @@ pub enum BinOp { Offset, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum UnOp { Not, Neg, } -#[derive(Clone, Debug)] -pub enum GeneratorKind { - Async(AsyncGeneratorKind), - Gen, +#[derive(Clone, Debug, Eq, PartialEq)] +pub enum CoroutineKind { + Async(CoroutineSource), + Coroutine, + Gen(CoroutineSource), } -#[derive(Clone, Debug)] -pub enum AsyncGeneratorKind { +#[derive(Clone, Debug, Eq, PartialEq)] +pub enum CoroutineSource { Block, Closure, Fn, @@ -139,7 +204,7 @@ pub(crate) type LocalDefId = Opaque; pub(crate) type Coverage = Opaque; /// The FakeReadCause describes the type of pattern why a FakeRead statement exists. -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum FakeReadCause { ForMatchGuard, ForMatchedPlace(LocalDefId), @@ -149,7 +214,7 @@ pub enum FakeReadCause { } /// Describes what kind of retag is to be performed -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq, Hash)] pub enum RetagKind { FnEntry, TwoPhase, @@ -157,7 +222,7 @@ pub enum RetagKind { Default, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq, Hash)] pub enum Variance { Covariant, Invariant, @@ -165,21 +230,27 @@ pub enum Variance { Bivariant, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub struct CopyNonOverlapping { pub src: Operand, pub dst: Operand, pub count: Operand, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum NonDivergingIntrinsic { Assume(Operand), CopyNonOverlapping(CopyNonOverlapping), } -#[derive(Clone, Debug)] -pub enum Statement { +#[derive(Clone, Debug, Eq, PartialEq)] +pub struct Statement { + pub kind: StatementKind, + pub span: Span, +} + +#[derive(Clone, Debug, Eq, PartialEq)] +pub enum StatementKind { Assign(Place, Rvalue), FakeRead(FakeReadCause, Place), SetDiscriminant { place: Place, variant_index: VariantIdx }, @@ -195,7 +266,7 @@ pub enum Statement { Nop, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum Rvalue { /// Creates a pointer with the indicated mutability to the place. /// @@ -209,8 +280,8 @@ pub enum Rvalue { /// `dest = Foo { x: ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case that `Foo` /// has a destructor. /// - /// Disallowed after deaggregation for all aggregate kinds except `Array` and `Generator`. After - /// generator lowering, `Generator` aggregate kinds are disallowed too. + /// Disallowed after deaggregation for all aggregate kinds except `Array` and `Coroutine`. After + /// coroutine lowering, `Coroutine` aggregate kinds are disallowed too. Aggregate(AggregateKind, Vec<Operand>), /// * `Offset` has the same semantics as `<*const T>::offset`, except that the second @@ -307,29 +378,30 @@ pub enum Rvalue { Use(Operand), } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum AggregateKind { Array(Ty), Tuple, Adt(AdtDef, VariantIdx, GenericArgs, Option<UserTypeAnnotationIndex>, Option<FieldIdx>), Closure(ClosureDef, GenericArgs), - Generator(GeneratorDef, GenericArgs, Movability), + Coroutine(CoroutineDef, GenericArgs, Movability), } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum Operand { Copy(Place), Move(Place), Constant(Constant), } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub struct Place { pub local: Local, + /// projection out of a place (access a field, deref a pointer, etc) pub projection: String, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub struct UserTypeProjection { pub base: UserTypeAnnotationIndex, pub projection: String, @@ -337,6 +409,8 @@ pub struct UserTypeProjection { pub type Local = usize; +pub const RETURN_LOCAL: Local = 0; + type FieldIdx = usize; /// The source-order index of a variant in a type. @@ -344,20 +418,20 @@ pub type VariantIdx = usize; type UserTypeAnnotationIndex = usize; -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub struct Constant { pub span: Span, pub user_ty: Option<UserTypeAnnotationIndex>, pub literal: Const, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub struct SwitchTarget { pub value: u128, pub target: usize, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum BorrowKind { /// Data must be immutable and is aliasable. Shared, @@ -375,26 +449,26 @@ pub enum BorrowKind { }, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum MutBorrowKind { Default, TwoPhaseBorrow, ClosureCapture, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, PartialEq, Eq)] pub enum Mutability { Not, Mut, } -#[derive(Copy, Clone, Debug)] +#[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum Safety { Unsafe, Normal, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum PointerCoercion { /// Go from a fn-item type to a fn-pointer type. ReifyFnPointer, @@ -421,7 +495,7 @@ pub enum PointerCoercion { Unsize, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum CastKind { PointerExposeAddress, PointerFromExposedAddress, @@ -436,12 +510,34 @@ pub enum CastKind { Transmute, } -#[derive(Clone, Debug)] +#[derive(Clone, Debug, Eq, PartialEq)] pub enum NullOp { /// Returns the size of a value of that type. SizeOf, /// Returns the minimum alignment of a type. AlignOf, /// Returns the offset of a field. - OffsetOf(Vec<FieldIdx>), + OffsetOf(Vec<(VariantIdx, FieldIdx)>), +} + +impl Operand { + pub fn ty(&self, locals: &[LocalDecl]) -> Ty { + match self { + Operand::Copy(place) | Operand::Move(place) => place.ty(locals), + Operand::Constant(c) => c.ty(), + } + } +} + +impl Constant { + pub fn ty(&self) -> Ty { + self.literal.ty() + } +} + +impl Place { + pub fn ty(&self, locals: &[LocalDecl]) -> Ty { + let _start_ty = locals[self.local].ty; + todo!("Implement projection") + } } diff --git a/compiler/stable_mir/src/mir/mono.rs b/compiler/stable_mir/src/mir/mono.rs new file mode 100644 index 000000000..8f5333498 --- /dev/null +++ b/compiler/stable_mir/src/mir/mono.rs @@ -0,0 +1,102 @@ +use crate::mir::Body; +use crate::ty::{FnDef, GenericArgs, IndexedVal, Ty}; +use crate::{with, CrateItem, DefId, Error, Opaque}; +use std::fmt::Debug; + +#[derive(Clone, Debug)] +pub enum MonoItem { + Fn(Instance), + Static(StaticDef), + GlobalAsm(Opaque), +} + +#[derive(Copy, Clone, Debug)] +pub struct Instance { + /// The type of instance. + pub kind: InstanceKind, + /// An ID used to get the instance definition from the compiler. + /// Do not use this field directly. + pub def: InstanceDef, +} + +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +pub enum InstanceKind { + /// A user defined item. + Item, + /// A compiler intrinsic function. + Intrinsic, + /// A virtual function definition stored in a VTable. + Virtual, + /// A compiler generated shim. + Shim, +} + +impl Instance { + /// Get the body of an Instance. The body will be eagerly monomorphized. + pub fn body(&self) -> Body { + with(|context| context.instance_body(self.def)) + } + + /// Get the instance type with generic substitutions applied and lifetimes erased. + pub fn ty(&self) -> Ty { + with(|context| context.instance_ty(self.def)) + } + + pub fn mangled_name(&self) -> String { + with(|context| context.instance_mangled_name(self.def)) + } + + /// Resolve an instance starting from a function definition and generic arguments. + pub fn resolve(def: FnDef, args: &GenericArgs) -> Result<Instance, crate::Error> { + with(|context| { + context.resolve_instance(def, args).ok_or_else(|| { + crate::Error::new(format!("Failed to resolve `{def:?}` with `{args:?}`")) + }) + }) + } +} + +/// Try to convert a crate item into an instance. +/// The item cannot be generic in order to be converted into an instance. +impl TryFrom<CrateItem> for Instance { + type Error = crate::Error; + + fn try_from(item: CrateItem) -> Result<Self, Self::Error> { + with(|context| { + if !context.requires_monomorphization(item.0) { + Ok(context.mono_instance(item)) + } else { + Err(Error::new("Item requires monomorphization".to_string())) + } + }) + } +} + +/// Try to convert an instance into a crate item. +/// Only user defined instances can be converted. +impl TryFrom<Instance> for CrateItem { + type Error = crate::Error; + + fn try_from(value: Instance) -> Result<Self, Self::Error> { + if value.kind == InstanceKind::Item { + Ok(CrateItem(with(|context| context.instance_def_id(value.def)))) + } else { + Err(Error::new(format!("Item kind `{:?}` cannot be converted", value.kind))) + } + } +} + +#[derive(Clone, Copy, Debug, PartialEq, Eq)] +pub struct InstanceDef(usize); + +#[derive(Clone, Copy, PartialEq, Eq, Debug)] +pub struct StaticDef(pub DefId); + +impl IndexedVal for InstanceDef { + fn to_val(index: usize) -> Self { + InstanceDef(index) + } + fn to_index(&self) -> usize { + self.0 + } +} diff --git a/compiler/stable_mir/src/mir/visit.rs b/compiler/stable_mir/src/mir/visit.rs new file mode 100644 index 000000000..806dced71 --- /dev/null +++ b/compiler/stable_mir/src/mir/visit.rs @@ -0,0 +1,414 @@ +//! # The Stable MIR Visitor +//! +//! ## Overview +//! +//! We currently only support an immutable visitor. +//! The structure of this visitor is similar to the ones internal to `rustc`, +//! and it follows the following conventions: +//! +//! For every mir item, the trait has a `visit_<item>` and a `super_<item>` method. +//! - `visit_<item>`, by default, calls `super_<item>` +//! - `super_<item>`, by default, destructures the `<item>` and calls `visit_<sub_item>` for +//! all sub-items that compose the original item. +//! +//! In order to implement a visitor, override the `visit_*` methods for the types you are +//! interested in analyzing, and invoke (within that method call) +//! `self.super_*` to continue to the traverse. +//! Avoid calling `super` methods in other circumstances. +//! +//! For the most part, we do not destructure things external to the +//! MIR, e.g., types, spans, etc, but simply visit them and stop. +//! This avoids duplication with other visitors like `TypeFoldable`. +//! +//! ## Updating +//! +//! The code is written in a very deliberate style intended to minimize +//! the chance of things being overlooked. +//! +//! Use pattern matching to reference fields and ensure that all +//! matches are exhaustive. +//! +//! For this to work, ALL MATCHES MUST BE EXHAUSTIVE IN FIELDS AND VARIANTS. +//! That means you never write `..` to skip over fields, nor do you write `_` +//! to skip over variants in a `match`. +//! +//! The only place that `_` is acceptable is to match a field (or +//! variant argument) that does not require visiting. + +use crate::mir::*; +use crate::ty::{Const, GenericArgs, Region, Ty}; +use crate::{Opaque, Span}; + +pub trait MirVisitor { + fn visit_body(&mut self, body: &Body) { + self.super_body(body) + } + + fn visit_basic_block(&mut self, bb: &BasicBlock) { + self.super_basic_block(bb) + } + + fn visit_ret_decl(&mut self, local: Local, decl: &LocalDecl) { + self.super_ret_decl(local, decl) + } + + fn visit_arg_decl(&mut self, local: Local, decl: &LocalDecl) { + self.super_arg_decl(local, decl) + } + + fn visit_local_decl(&mut self, local: Local, decl: &LocalDecl) { + self.super_local_decl(local, decl) + } + + fn visit_statement(&mut self, stmt: &Statement, location: Location) { + self.super_statement(stmt, location) + } + + fn visit_terminator(&mut self, term: &Terminator, location: Location) { + self.super_terminator(term, location) + } + + fn visit_span(&mut self, span: &Span) { + self.super_span(span) + } + + fn visit_place(&mut self, place: &Place, ptx: PlaceContext, location: Location) { + self.super_place(place, ptx, location) + } + + fn visit_local(&mut self, local: &Local, ptx: PlaceContext, location: Location) { + let _ = (local, ptx, location); + } + + fn visit_rvalue(&mut self, rvalue: &Rvalue, location: Location) { + self.super_rvalue(rvalue, location) + } + + fn visit_operand(&mut self, operand: &Operand, location: Location) { + self.super_operand(operand, location) + } + + fn visit_user_type_projection(&mut self, projection: &UserTypeProjection) { + self.super_user_type_projection(projection) + } + + fn visit_ty(&mut self, ty: &Ty, location: Location) { + let _ = location; + self.super_ty(ty) + } + + fn visit_constant(&mut self, constant: &Constant, location: Location) { + self.super_constant(constant, location) + } + + fn visit_const(&mut self, constant: &Const, location: Location) { + self.super_const(constant, location) + } + + fn visit_region(&mut self, region: &Region, location: Location) { + let _ = location; + self.super_region(region) + } + + fn visit_args(&mut self, args: &GenericArgs, location: Location) { + let _ = location; + self.super_args(args) + } + + fn visit_assert_msg(&mut self, msg: &AssertMessage, location: Location) { + self.super_assert_msg(msg, location) + } + + fn super_body(&mut self, body: &Body) { + let Body { blocks, locals: _, arg_count } = body; + + for bb in blocks { + self.visit_basic_block(bb); + } + + self.visit_ret_decl(RETURN_LOCAL, body.ret_local()); + + for (idx, arg) in body.arg_locals().iter().enumerate() { + self.visit_arg_decl(idx + 1, arg) + } + + let local_start = arg_count + 1; + for (idx, arg) in body.arg_locals().iter().enumerate() { + self.visit_local_decl(idx + local_start, arg) + } + } + + fn super_basic_block(&mut self, bb: &BasicBlock) { + let BasicBlock { statements, terminator } = bb; + for stmt in statements { + self.visit_statement(stmt, Location(stmt.span)); + } + self.visit_terminator(terminator, Location(terminator.span)); + } + + fn super_local_decl(&mut self, local: Local, decl: &LocalDecl) { + let _ = local; + let LocalDecl { ty, span } = decl; + self.visit_ty(ty, Location(*span)); + } + + fn super_ret_decl(&mut self, local: Local, decl: &LocalDecl) { + self.super_local_decl(local, decl) + } + + fn super_arg_decl(&mut self, local: Local, decl: &LocalDecl) { + self.super_local_decl(local, decl) + } + + fn super_statement(&mut self, stmt: &Statement, location: Location) { + let Statement { kind, span } = stmt; + self.visit_span(span); + match kind { + StatementKind::Assign(place, rvalue) => { + self.visit_place(place, PlaceContext::MUTATING, location); + self.visit_rvalue(rvalue, location); + } + StatementKind::FakeRead(_, place) => { + self.visit_place(place, PlaceContext::NON_MUTATING, location); + } + StatementKind::SetDiscriminant { place, .. } => { + self.visit_place(place, PlaceContext::MUTATING, location); + } + StatementKind::Deinit(place) => { + self.visit_place(place, PlaceContext::MUTATING, location); + } + StatementKind::StorageLive(local) => { + self.visit_local(local, PlaceContext::NON_USE, location); + } + StatementKind::StorageDead(local) => { + self.visit_local(local, PlaceContext::NON_USE, location); + } + StatementKind::Retag(_, place) => { + self.visit_place(place, PlaceContext::MUTATING, location); + } + StatementKind::PlaceMention(place) => { + self.visit_place(place, PlaceContext::NON_MUTATING, location); + } + StatementKind::AscribeUserType { place, projections, variance: _ } => { + self.visit_place(place, PlaceContext::NON_USE, location); + self.visit_user_type_projection(projections); + } + StatementKind::Coverage(coverage) => visit_opaque(coverage), + StatementKind::Intrinsic(intrisic) => match intrisic { + NonDivergingIntrinsic::Assume(operand) => { + self.visit_operand(operand, location); + } + NonDivergingIntrinsic::CopyNonOverlapping(CopyNonOverlapping { + src, + dst, + count, + }) => { + self.visit_operand(src, location); + self.visit_operand(dst, location); + self.visit_operand(count, location); + } + }, + StatementKind::ConstEvalCounter => {} + StatementKind::Nop => {} + } + } + + fn super_terminator(&mut self, term: &Terminator, location: Location) { + let Terminator { kind, span } = term; + self.visit_span(&span); + match kind { + TerminatorKind::Goto { .. } + | TerminatorKind::Resume + | TerminatorKind::Abort + | TerminatorKind::Unreachable + | TerminatorKind::CoroutineDrop => {} + TerminatorKind::Assert { cond, expected: _, msg, target: _, unwind: _ } => { + self.visit_operand(cond, location); + self.visit_assert_msg(msg, location); + } + TerminatorKind::Drop { place, target: _, unwind: _ } => { + self.visit_place(place, PlaceContext::MUTATING, location); + } + TerminatorKind::Call { func, args, destination, target: _, unwind: _ } => { + self.visit_operand(func, location); + for arg in args { + self.visit_operand(arg, location); + } + self.visit_place(destination, PlaceContext::MUTATING, location); + } + TerminatorKind::InlineAsm { operands, .. } => { + for op in operands { + let InlineAsmOperand { in_value, out_place, raw_rpr: _ } = op; + if let Some(input) = in_value { + self.visit_operand(input, location); + } + if let Some(output) = out_place { + self.visit_place(output, PlaceContext::MUTATING, location); + } + } + } + TerminatorKind::Return => { + let local = RETURN_LOCAL; + self.visit_local(&local, PlaceContext::NON_MUTATING, location); + } + TerminatorKind::SwitchInt { discr, targets: _, otherwise: _ } => { + self.visit_operand(discr, location); + } + } + } + + fn super_span(&mut self, span: &Span) { + let _ = span; + } + + fn super_place(&mut self, place: &Place, ptx: PlaceContext, location: Location) { + let _ = location; + let _ = ptx; + visit_opaque(&Opaque(place.projection.clone())); + } + + fn super_rvalue(&mut self, rvalue: &Rvalue, location: Location) { + match rvalue { + Rvalue::AddressOf(mutability, place) => { + let pcx = PlaceContext { is_mut: *mutability == Mutability::Mut }; + self.visit_place(place, pcx, location); + } + Rvalue::Aggregate(_, operands) => { + for op in operands { + self.visit_operand(op, location); + } + } + Rvalue::BinaryOp(_, lhs, rhs) | Rvalue::CheckedBinaryOp(_, lhs, rhs) => { + self.visit_operand(lhs, location); + self.visit_operand(rhs, location); + } + Rvalue::Cast(_, op, ty) => { + self.visit_operand(op, location); + self.visit_ty(ty, location); + } + Rvalue::CopyForDeref(place) | Rvalue::Discriminant(place) | Rvalue::Len(place) => { + self.visit_place(place, PlaceContext::NON_MUTATING, location); + } + Rvalue::Ref(region, kind, place) => { + self.visit_region(region, location); + let pcx = PlaceContext { is_mut: matches!(kind, BorrowKind::Mut { .. }) }; + self.visit_place(place, pcx, location); + } + Rvalue::Repeat(op, constant) => { + self.visit_operand(op, location); + self.visit_const(constant, location); + } + Rvalue::ShallowInitBox(op, ty) => { + self.visit_ty(ty, location); + self.visit_operand(op, location) + } + Rvalue::ThreadLocalRef(_) => {} + Rvalue::NullaryOp(_, ty) => { + self.visit_ty(ty, location); + } + Rvalue::UnaryOp(_, op) | Rvalue::Use(op) => { + self.visit_operand(op, location); + } + } + } + + fn super_operand(&mut self, operand: &Operand, location: Location) { + match operand { + Operand::Copy(place) | Operand::Move(place) => { + self.visit_place(place, PlaceContext::NON_MUTATING, location) + } + Operand::Constant(constant) => { + self.visit_constant(constant, location); + } + } + } + + fn super_user_type_projection(&mut self, projection: &UserTypeProjection) { + // This is a no-op on mir::Visitor. + let _ = projection; + } + + fn super_ty(&mut self, ty: &Ty) { + let _ = ty; + } + + fn super_constant(&mut self, constant: &Constant, location: Location) { + let Constant { span, user_ty: _, literal } = constant; + self.visit_span(span); + self.visit_const(literal, location); + } + + fn super_const(&mut self, constant: &Const, location: Location) { + let Const { kind: _, ty, id: _ } = constant; + self.visit_ty(ty, location); + } + + fn super_region(&mut self, region: &Region) { + let _ = region; + } + + fn super_args(&mut self, args: &GenericArgs) { + let _ = args; + } + + fn super_assert_msg(&mut self, msg: &AssertMessage, location: Location) { + match msg { + AssertMessage::BoundsCheck { len, index } => { + self.visit_operand(len, location); + self.visit_operand(index, location); + } + AssertMessage::Overflow(_, left, right) => { + self.visit_operand(left, location); + self.visit_operand(right, location); + } + AssertMessage::OverflowNeg(op) + | AssertMessage::DivisionByZero(op) + | AssertMessage::RemainderByZero(op) => { + self.visit_operand(op, location); + } + AssertMessage::ResumedAfterReturn(_) | AssertMessage::ResumedAfterPanic(_) => { //nothing to visit + } + AssertMessage::MisalignedPointerDereference { required, found } => { + self.visit_operand(required, location); + self.visit_operand(found, location); + } + } + } +} + +/// This function is a no-op that gets used to ensure this visitor is kept up-to-date. +/// +/// The idea is that whenever we replace an Opaque type by a real type, the compiler will fail +/// when trying to invoke `visit_opaque`. +/// +/// If you are here because your compilation is broken, replace the failing call to `visit_opaque()` +/// by a `visit_<CONSTRUCT>` for your construct. +fn visit_opaque(_: &Opaque) {} + +/// The location of a statement / terminator in the code and the CFG. +#[derive(Clone, Copy, PartialEq, Eq)] +pub struct Location(Span); + +impl Location { + pub fn span(&self) -> Span { + self.0 + } +} + +/// Information about a place's usage. +#[derive(Copy, Clone, PartialEq, Eq, Hash)] +pub struct PlaceContext { + /// Whether the access is mutable or not. Keep this private so we can increment the type in a + /// backward compatible manner. + is_mut: bool, +} + +impl PlaceContext { + const MUTATING: Self = PlaceContext { is_mut: true }; + const NON_MUTATING: Self = PlaceContext { is_mut: false }; + const NON_USE: Self = PlaceContext { is_mut: false }; + + pub fn is_mutating(&self) -> bool { + self.is_mut + } +} |