diff options
Diffstat (limited to 'compiler/rustc_middle/src/thir.rs')
| -rw-r--r-- | compiler/rustc_middle/src/thir.rs | 317 |
1 files changed, 295 insertions, 22 deletions
diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs index 89934e435..3086082fe 100644 --- a/compiler/rustc_middle/src/thir.rs +++ b/compiler/rustc_middle/src/thir.rs @@ -16,16 +16,19 @@ use rustc_hir::RangeEnd; use rustc_index::newtype_index; use rustc_index::IndexVec; use rustc_middle::middle::region; -use rustc_middle::mir::interpret::AllocId; +use rustc_middle::mir::interpret::{AllocId, Scalar}; use rustc_middle::mir::{self, BinOp, BorrowKind, FakeReadCause, Mutability, UnOp}; use rustc_middle::ty::adjustment::PointerCoercion; -use rustc_middle::ty::GenericArgsRef; -use rustc_middle::ty::{self, AdtDef, FnSig, List, Ty, UpvarArgs}; -use rustc_middle::ty::{CanonicalUserType, CanonicalUserTypeAnnotation}; +use rustc_middle::ty::layout::IntegerExt; +use rustc_middle::ty::{ + self, AdtDef, CanonicalUserType, CanonicalUserTypeAnnotation, FnSig, GenericArgsRef, List, Ty, + TyCtxt, UpvarArgs, +}; use rustc_span::def_id::LocalDefId; -use rustc_span::{sym, Span, Symbol, DUMMY_SP}; -use rustc_target::abi::{FieldIdx, VariantIdx}; +use rustc_span::{sym, ErrorGuaranteed, Span, Symbol, DUMMY_SP}; +use rustc_target::abi::{FieldIdx, Integer, Size, VariantIdx}; use rustc_target::asm::InlineAsmRegOrRegClass; +use std::cmp::Ordering; use std::fmt; use std::ops::Index; @@ -381,9 +384,9 @@ pub enum ExprKind<'tcx> { VarRef { id: LocalVarId, }, - /// Used to represent upvars mentioned in a closure/generator + /// Used to represent upvars mentioned in a closure/coroutine UpvarRef { - /// DefId of the closure/generator + /// DefId of the closure/coroutine closure_def_id: DefId, /// HirId of the root variable @@ -489,7 +492,7 @@ pub enum ExprKind<'tcx> { /// Field offset (`offset_of!`) OffsetOf { container: Ty<'tcx>, - fields: &'tcx List<FieldIdx>, + fields: &'tcx List<(VariantIdx, FieldIdx)>, }, /// An expression taking a reference to a thread local. ThreadLocalRef(DefId), @@ -581,13 +584,13 @@ pub enum BindingMode { ByRef(BorrowKind), } -#[derive(Clone, Debug, HashStable)] +#[derive(Clone, Debug, HashStable, TypeVisitable)] pub struct FieldPat<'tcx> { pub field: FieldIdx, pub pattern: Box<Pat<'tcx>>, } -#[derive(Clone, Debug, HashStable)] +#[derive(Clone, Debug, HashStable, TypeVisitable)] pub struct Pat<'tcx> { pub ty: Ty<'tcx>, pub span: Span, @@ -632,10 +635,11 @@ impl<'tcx> Pat<'tcx> { use PatKind::*; match &self.kind { - Wild | Range(..) | Binding { subpattern: None, .. } | Constant { .. } => {} + Wild | Range(..) | Binding { subpattern: None, .. } | Constant { .. } | Error(_) => {} AscribeUserType { subpattern, .. } | Binding { subpattern: Some(subpattern), .. } - | Deref { subpattern } => subpattern.walk_(it), + | Deref { subpattern } + | InlineConstant { subpattern, .. } => subpattern.walk_(it), Leaf { subpatterns } | Variant { subpatterns, .. } => { subpatterns.iter().for_each(|field| field.pattern.walk_(it)) } @@ -647,6 +651,21 @@ impl<'tcx> Pat<'tcx> { } } + /// Whether the pattern has a `PatKind::Error` nested within. + pub fn pat_error_reported(&self) -> Result<(), ErrorGuaranteed> { + let mut error = None; + self.walk(|pat| { + if let PatKind::Error(e) = pat.kind && error.is_none() { + error = Some(e); + } + error.is_none() + }); + match error { + None => Ok(()), + Some(e) => Err(e), + } + } + /// Walk the pattern in left-to-right order. /// /// If you always want to recurse, prefer this method over `walk`. @@ -664,7 +683,7 @@ impl<'tcx> IntoDiagnosticArg for Pat<'tcx> { } } -#[derive(Clone, Debug, HashStable)] +#[derive(Clone, Debug, HashStable, TypeVisitable)] pub struct Ascription<'tcx> { pub annotation: CanonicalUserTypeAnnotation<'tcx>, /// Variance to use when relating the `user_ty` to the **type of the value being @@ -688,7 +707,7 @@ pub struct Ascription<'tcx> { pub variance: ty::Variance, } -#[derive(Clone, Debug, HashStable)] +#[derive(Clone, Debug, HashStable, TypeVisitable)] pub enum PatKind<'tcx> { /// A wildcard pattern: `_`. Wild, @@ -702,7 +721,9 @@ pub enum PatKind<'tcx> { Binding { mutability: Mutability, name: Symbol, + #[type_visitable(ignore)] mode: BindingMode, + #[type_visitable(ignore)] var: LocalVarId, ty: Ty<'tcx>, subpattern: Option<Box<Pat<'tcx>>>, @@ -746,6 +767,22 @@ pub enum PatKind<'tcx> { value: mir::Const<'tcx>, }, + /// Inline constant found while lowering a pattern. + InlineConstant { + /// [LocalDefId] of the constant, we need this so that we have a + /// reference that can be used by unsafety checking to visit nested + /// unevaluated constants. + def: LocalDefId, + /// If the inline constant is used in a range pattern, this subpattern + /// represents the range (if both ends are inline constants, there will + /// be multiple InlineConstant wrappers). + /// + /// Otherwise, the actual pattern that the constant lowered to. As with + /// other constants, inline constants are matched structurally where + /// possible. + subpattern: Box<Pat<'tcx>>, + }, + Range(Box<PatRange<'tcx>>), /// Matches against a slice, checking the length and extracting elements. @@ -769,13 +806,249 @@ pub enum PatKind<'tcx> { Or { pats: Box<[Box<Pat<'tcx>>]>, }, + + /// An error has been encountered during lowering. We probably shouldn't report more lints + /// related to this pattern. + Error(ErrorGuaranteed), } -#[derive(Clone, Debug, PartialEq, HashStable)] +/// A range pattern. +/// The boundaries must be of the same type and that type must be numeric. +#[derive(Clone, Debug, PartialEq, HashStable, TypeVisitable)] pub struct PatRange<'tcx> { - pub lo: mir::Const<'tcx>, - pub hi: mir::Const<'tcx>, + pub lo: PatRangeBoundary<'tcx>, + pub hi: PatRangeBoundary<'tcx>, + #[type_visitable(ignore)] pub end: RangeEnd, + pub ty: Ty<'tcx>, +} + +impl<'tcx> PatRange<'tcx> { + /// Whether this range covers the full extent of possible values (best-effort, we ignore floats). + #[inline] + pub fn is_full_range(&self, tcx: TyCtxt<'tcx>) -> Option<bool> { + let (min, max, size, bias) = match *self.ty.kind() { + ty::Char => (0, std::char::MAX as u128, Size::from_bits(32), 0), + ty::Int(ity) => { + let size = Integer::from_int_ty(&tcx, ity).size(); + let max = size.truncate(u128::MAX); + let bias = 1u128 << (size.bits() - 1); + (0, max, size, bias) + } + ty::Uint(uty) => { + let size = Integer::from_uint_ty(&tcx, uty).size(); + let max = size.unsigned_int_max(); + (0, max, size, 0) + } + _ => return None, + }; + + // We want to compare ranges numerically, but the order of the bitwise representation of + // signed integers does not match their numeric order. Thus, to correct the ordering, we + // need to shift the range of signed integers to correct the comparison. This is achieved by + // XORing with a bias (see pattern/deconstruct_pat.rs for another pertinent example of this + // pattern). + // + // Also, for performance, it's important to only do the second `try_to_bits` if necessary. + let lo_is_min = match self.lo { + PatRangeBoundary::NegInfinity => true, + PatRangeBoundary::Finite(value) => { + let lo = value.try_to_bits(size).unwrap() ^ bias; + lo <= min + } + PatRangeBoundary::PosInfinity => false, + }; + if lo_is_min { + let hi_is_max = match self.hi { + PatRangeBoundary::NegInfinity => false, + PatRangeBoundary::Finite(value) => { + let hi = value.try_to_bits(size).unwrap() ^ bias; + hi > max || hi == max && self.end == RangeEnd::Included + } + PatRangeBoundary::PosInfinity => true, + }; + if hi_is_max { + return Some(true); + } + } + Some(false) + } + + #[inline] + pub fn contains( + &self, + value: mir::Const<'tcx>, + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + ) -> Option<bool> { + use Ordering::*; + debug_assert_eq!(self.ty, value.ty()); + let ty = self.ty; + let value = PatRangeBoundary::Finite(value); + // For performance, it's important to only do the second comparison if necessary. + Some( + match self.lo.compare_with(value, ty, tcx, param_env)? { + Less | Equal => true, + Greater => false, + } && match value.compare_with(self.hi, ty, tcx, param_env)? { + Less => true, + Equal => self.end == RangeEnd::Included, + Greater => false, + }, + ) + } + + #[inline] + pub fn overlaps( + &self, + other: &Self, + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + ) -> Option<bool> { + use Ordering::*; + debug_assert_eq!(self.ty, other.ty); + // For performance, it's important to only do the second comparison if necessary. + Some( + match other.lo.compare_with(self.hi, self.ty, tcx, param_env)? { + Less => true, + Equal => self.end == RangeEnd::Included, + Greater => false, + } && match self.lo.compare_with(other.hi, self.ty, tcx, param_env)? { + Less => true, + Equal => other.end == RangeEnd::Included, + Greater => false, + }, + ) + } +} + +impl<'tcx> fmt::Display for PatRange<'tcx> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + if let PatRangeBoundary::Finite(value) = &self.lo { + write!(f, "{value}")?; + } + if let PatRangeBoundary::Finite(value) = &self.hi { + write!(f, "{}", self.end)?; + write!(f, "{value}")?; + } else { + // `0..` is parsed as an inclusive range, we must display it correctly. + write!(f, "..")?; + } + Ok(()) + } +} + +/// A (possibly open) boundary of a range pattern. +/// If present, the const must be of a numeric type. +#[derive(Copy, Clone, Debug, PartialEq, HashStable, TypeVisitable)] +pub enum PatRangeBoundary<'tcx> { + Finite(mir::Const<'tcx>), + NegInfinity, + PosInfinity, +} + +impl<'tcx> PatRangeBoundary<'tcx> { + #[inline] + pub fn is_finite(self) -> bool { + matches!(self, Self::Finite(..)) + } + #[inline] + pub fn as_finite(self) -> Option<mir::Const<'tcx>> { + match self { + Self::Finite(value) => Some(value), + Self::NegInfinity | Self::PosInfinity => None, + } + } + #[inline] + pub fn to_const(self, ty: Ty<'tcx>, tcx: TyCtxt<'tcx>) -> mir::Const<'tcx> { + match self { + Self::Finite(value) => value, + Self::NegInfinity => { + // Unwrap is ok because the type is known to be numeric. + let c = ty.numeric_min_val(tcx).unwrap(); + mir::Const::from_ty_const(c, tcx) + } + Self::PosInfinity => { + // Unwrap is ok because the type is known to be numeric. + let c = ty.numeric_max_val(tcx).unwrap(); + mir::Const::from_ty_const(c, tcx) + } + } + } + pub fn eval_bits(self, ty: Ty<'tcx>, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> u128 { + match self { + Self::Finite(value) => value.eval_bits(tcx, param_env), + Self::NegInfinity => { + // Unwrap is ok because the type is known to be numeric. + ty.numeric_min_and_max_as_bits(tcx).unwrap().0 + } + Self::PosInfinity => { + // Unwrap is ok because the type is known to be numeric. + ty.numeric_min_and_max_as_bits(tcx).unwrap().1 + } + } + } + + #[instrument(skip(tcx, param_env), level = "debug", ret)] + pub fn compare_with( + self, + other: Self, + ty: Ty<'tcx>, + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + ) -> Option<Ordering> { + use PatRangeBoundary::*; + match (self, other) { + // When comparing with infinities, we must remember that `0u8..` and `0u8..=255` + // describe the same range. These two shortcuts are ok, but for the rest we must check + // bit values. + (PosInfinity, PosInfinity) => return Some(Ordering::Equal), + (NegInfinity, NegInfinity) => return Some(Ordering::Equal), + + // This code is hot when compiling matches with many ranges. So we + // special-case extraction of evaluated scalars for speed, for types where + // raw data comparisons are appropriate. E.g. `unicode-normalization` has + // many ranges such as '\u{037A}'..='\u{037F}', and chars can be compared + // in this way. + (Finite(mir::Const::Ty(a)), Finite(mir::Const::Ty(b))) + if matches!(ty.kind(), ty::Uint(_) | ty::Char) => + { + return Some(a.kind().cmp(&b.kind())); + } + ( + Finite(mir::Const::Val(mir::ConstValue::Scalar(Scalar::Int(a)), _)), + Finite(mir::Const::Val(mir::ConstValue::Scalar(Scalar::Int(b)), _)), + ) if matches!(ty.kind(), ty::Uint(_) | ty::Char) => return Some(a.cmp(&b)), + _ => {} + } + + let a = self.eval_bits(ty, tcx, param_env); + let b = other.eval_bits(ty, tcx, param_env); + + match ty.kind() { + ty::Float(ty::FloatTy::F32) => { + use rustc_apfloat::Float; + let a = rustc_apfloat::ieee::Single::from_bits(a); + let b = rustc_apfloat::ieee::Single::from_bits(b); + a.partial_cmp(&b) + } + ty::Float(ty::FloatTy::F64) => { + use rustc_apfloat::Float; + let a = rustc_apfloat::ieee::Double::from_bits(a); + let b = rustc_apfloat::ieee::Double::from_bits(b); + a.partial_cmp(&b) + } + ty::Int(ity) => { + use rustc_middle::ty::layout::IntegerExt; + let size = rustc_target::abi::Integer::from_int_ty(&tcx, *ity).size(); + let a = size.sign_extend(a) as i128; + let b = size.sign_extend(b) as i128; + Some(a.cmp(&b)) + } + ty::Uint(_) | ty::Char => Some(a.cmp(&b)), + _ => bug!(), + } + } } impl<'tcx> fmt::Display for Pat<'tcx> { @@ -901,11 +1174,10 @@ impl<'tcx> fmt::Display for Pat<'tcx> { write!(f, "{subpattern}") } PatKind::Constant { value } => write!(f, "{value}"), - PatKind::Range(box PatRange { lo, hi, end }) => { - write!(f, "{lo}")?; - write!(f, "{end}")?; - write!(f, "{hi}") + PatKind::InlineConstant { def: _, ref subpattern } => { + write!(f, "{} (from inline const)", subpattern) } + PatKind::Range(ref range) => write!(f, "{range}"), PatKind::Slice { ref prefix, ref slice, ref suffix } | PatKind::Array { ref prefix, ref slice, ref suffix } => { write!(f, "[")?; @@ -931,6 +1203,7 @@ impl<'tcx> fmt::Display for Pat<'tcx> { } Ok(()) } + PatKind::Error(_) => write!(f, "<error>"), } } } |