71 lines
2 KiB
Rust
71 lines
2 KiB
Rust
// Helpers for handling cast expressions, used in both
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// typeck and codegen.
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use crate::ty::{self, Ty};
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use syntax::ast;
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use rustc_macros::HashStable;
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/// Types that are represented as ints.
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#[derive(Copy, Clone, Debug, PartialEq, Eq)]
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pub enum IntTy {
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U(ast::UintTy),
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I,
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CEnum,
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Bool,
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Char
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}
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// Valid types for the result of a non-coercion cast
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#[derive(Copy, Clone, Debug, PartialEq, Eq)]
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pub enum CastTy<'tcx> {
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/// Various types that are represented as ints and handled mostly
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/// in the same way, merged for easier matching.
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Int(IntTy),
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/// Floating-Point types
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Float,
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/// Function Pointers
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FnPtr,
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/// Raw pointers
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Ptr(ty::TypeAndMut<'tcx>),
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/// References
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RPtr(ty::TypeAndMut<'tcx>),
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}
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/// Cast Kind. See RFC 401 (or librustc_typeck/check/cast.rs)
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#[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
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pub enum CastKind {
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CoercionCast,
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PtrPtrCast,
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PtrAddrCast,
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AddrPtrCast,
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NumericCast,
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EnumCast,
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PrimIntCast,
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U8CharCast,
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ArrayPtrCast,
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FnPtrPtrCast,
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FnPtrAddrCast
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}
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impl<'tcx> CastTy<'tcx> {
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/// Returns `Some` for integral/pointer casts.
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/// casts like unsizing casts will return `None`
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pub fn from_ty(t: Ty<'tcx>) -> Option<CastTy<'tcx>> {
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match t.sty {
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ty::Bool => Some(CastTy::Int(IntTy::Bool)),
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ty::Char => Some(CastTy::Int(IntTy::Char)),
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ty::Int(_) => Some(CastTy::Int(IntTy::I)),
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ty::Infer(ty::InferTy::IntVar(_)) => Some(CastTy::Int(IntTy::I)),
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ty::Infer(ty::InferTy::FloatVar(_)) => Some(CastTy::Float),
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ty::Uint(u) => Some(CastTy::Int(IntTy::U(u))),
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ty::Float(_) => Some(CastTy::Float),
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ty::Adt(d,_) if d.is_enum() && d.is_payloadfree() =>
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Some(CastTy::Int(IntTy::CEnum)),
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ty::RawPtr(mt) => Some(CastTy::Ptr(mt)),
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ty::Ref(_, ty, mutbl) => Some(CastTy::RPtr(ty::TypeAndMut { ty, mutbl })),
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ty::FnPtr(..) => Some(CastTy::FnPtr),
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_ => None,
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}
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}
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}
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