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Diffstat (limited to 'rust/zerocopy-derive/repr.rs')
| -rw-r--r-- | rust/zerocopy-derive/repr.rs | 851 |
1 files changed, 851 insertions, 0 deletions
diff --git a/rust/zerocopy-derive/repr.rs b/rust/zerocopy-derive/repr.rs new file mode 100644 index 000000000000..74fd376d9fda --- /dev/null +++ b/rust/zerocopy-derive/repr.rs @@ -0,0 +1,851 @@ +// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT + +// Copyright 2019 The Fuchsia Authors +// +// Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0 +// <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT +// license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option. +// This file may not be copied, modified, or distributed except according to +// those terms. + +use core::{ + convert::{Infallible, TryFrom}, + num::NonZeroU32, +}; + +use proc_macro2::{Span, TokenStream}; +use quote::{quote_spanned, ToTokens, TokenStreamExt as _}; +use syn::{ + punctuated::Punctuated, spanned::Spanned as _, token::Comma, Attribute, Error, LitInt, Meta, + MetaList, +}; + +/// The computed representation of a type. +/// +/// This is the result of processing all `#[repr(...)]` attributes on a type, if +/// any. A `Repr` is only capable of representing legal combinations of +/// `#[repr(...)]` attributes. +#[cfg_attr(test, derive(Copy, Clone, Debug))] +pub(crate) enum Repr<Prim, Packed> { + /// `#[repr(transparent)]` + Transparent(Span), + /// A compound representation: `repr(C)`, `repr(Rust)`, or `repr(Int)` + /// optionally combined with `repr(packed(...))` or `repr(align(...))` + Compound(Spanned<CompoundRepr<Prim>>, Option<Spanned<AlignRepr<Packed>>>), +} + +/// A compound representation: `repr(C)`, `repr(Rust)`, or `repr(Int)`. +#[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] +pub(crate) enum CompoundRepr<Prim> { + C, + Rust, + Primitive(Prim), +} + +/// `repr(Int)` +#[derive(Copy, Clone)] +#[cfg_attr(test, derive(Debug, Eq, PartialEq))] +pub(crate) enum PrimitiveRepr { + U8, + U16, + U32, + U64, + U128, + Usize, + I8, + I16, + I32, + I64, + I128, + Isize, +} + +/// `repr(packed(...))` or `repr(align(...))` +#[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] +pub(crate) enum AlignRepr<Packed> { + Packed(Packed), + Align(NonZeroU32), +} + +/// The representations which can legally appear on a struct or union type. +pub(crate) type StructUnionRepr = Repr<Infallible, NonZeroU32>; + +/// The representations which can legally appear on an enum type. +pub(crate) type EnumRepr = Repr<PrimitiveRepr, Infallible>; + +impl<Prim, Packed> Repr<Prim, Packed> { + /// Gets the name of this "repr type" - the non-align `repr(X)` that is used + /// in prose to refer to this type. + /// + /// For example, we would refer to `#[repr(C, align(4))] struct Foo { ... }` + /// as a "`repr(C)` struct". + pub(crate) fn repr_type_name(&self) -> &str + where + Prim: Copy + With<PrimitiveRepr>, + { + use CompoundRepr::*; + use PrimitiveRepr::*; + use Repr::*; + match self { + Transparent(_span) => "repr(transparent)", + Compound(Spanned { t: repr, span: _ }, _align) => match repr { + C => "repr(C)", + Rust => "repr(Rust)", + Primitive(prim) => prim.with(|prim| match prim { + U8 => "repr(u8)", + U16 => "repr(u16)", + U32 => "repr(u32)", + U64 => "repr(u64)", + U128 => "repr(u128)", + Usize => "repr(usize)", + I8 => "repr(i8)", + I16 => "repr(i16)", + I32 => "repr(i32)", + I64 => "repr(i64)", + I128 => "repr(i128)", + Isize => "repr(isize)", + }), + }, + } + } + + pub(crate) fn is_transparent(&self) -> bool { + matches!(self, Repr::Transparent(_)) + } + + pub(crate) fn is_c(&self) -> bool { + use CompoundRepr::*; + matches!(self, Repr::Compound(Spanned { t: C, span: _ }, _align)) + } + + pub(crate) fn is_primitive(&self) -> bool { + use CompoundRepr::*; + matches!(self, Repr::Compound(Spanned { t: Primitive(_), span: _ }, _align)) + } + + pub(crate) fn get_packed(&self) -> Option<&Packed> { + use AlignRepr::*; + use Repr::*; + if let Compound(_, Some(Spanned { t: Packed(p), span: _ })) = self { + Some(p) + } else { + None + } + } + + pub(crate) fn get_align(&self) -> Option<Spanned<NonZeroU32>> { + use AlignRepr::*; + use Repr::*; + if let Compound(_, Some(Spanned { t: Align(n), span })) = self { + Some(Spanned::new(*n, *span)) + } else { + None + } + } + + pub(crate) fn is_align_gt_1(&self) -> bool { + self.get_align().map(|n| n.t.get() > 1).unwrap_or(false) + } + + /// When deriving `Unaligned`, validate that the decorated type has no + /// `#[repr(align(N))]` attribute where `N > 1`. If no such attribute exists + /// (including if `N == 1`), this returns `Ok(())`, and otherwise it returns + /// a descriptive error. + pub(crate) fn unaligned_validate_no_align_gt_1(&self) -> Result<(), Error> { + if let Some(n) = self.get_align().filter(|n| n.t.get() > 1) { + Err(Error::new( + n.span, + "cannot derive `Unaligned` on type with alignment greater than 1", + )) + } else { + Ok(()) + } + } +} + +impl<Prim> Repr<Prim, NonZeroU32> { + /// Does `self` describe a `#[repr(packed)]` or `#[repr(packed(1))]` type? + pub(crate) fn is_packed_1(&self) -> bool { + self.get_packed().map(|n| n.get() == 1).unwrap_or(false) + } +} + +impl<Packed> Repr<PrimitiveRepr, Packed> { + fn get_primitive(&self) -> Option<&PrimitiveRepr> { + use CompoundRepr::*; + use Repr::*; + if let Compound(Spanned { t: Primitive(p), span: _ }, _align) = self { + Some(p) + } else { + None + } + } + + /// Does `self` describe a `#[repr(u8)]` type? + pub(crate) fn is_u8(&self) -> bool { + matches!(self.get_primitive(), Some(PrimitiveRepr::U8)) + } + + /// Does `self` describe a `#[repr(i8)]` type? + pub(crate) fn is_i8(&self) -> bool { + matches!(self.get_primitive(), Some(PrimitiveRepr::I8)) + } +} + +impl<Prim, Packed> ToTokens for Repr<Prim, Packed> +where + Prim: With<PrimitiveRepr> + Copy, + Packed: With<NonZeroU32> + Copy, +{ + fn to_tokens(&self, ts: &mut TokenStream) { + use Repr::*; + match self { + Transparent(span) => ts.append_all(quote_spanned! { *span=> #[repr(transparent)] }), + Compound(repr, align) => { + repr.to_tokens(ts); + if let Some(align) = align { + align.to_tokens(ts); + } + } + } + } +} + +impl<Prim: With<PrimitiveRepr> + Copy> ToTokens for Spanned<CompoundRepr<Prim>> { + fn to_tokens(&self, ts: &mut TokenStream) { + use CompoundRepr::*; + match &self.t { + C => ts.append_all(quote_spanned! { self.span=> #[repr(C)] }), + Rust => ts.append_all(quote_spanned! { self.span=> #[repr(Rust)] }), + Primitive(prim) => prim.with(|prim| Spanned::new(prim, self.span).to_tokens(ts)), + } + } +} + +impl ToTokens for Spanned<PrimitiveRepr> { + fn to_tokens(&self, ts: &mut TokenStream) { + use PrimitiveRepr::*; + match self.t { + U8 => ts.append_all(quote_spanned! { self.span => #[repr(u8)] }), + U16 => ts.append_all(quote_spanned! { self.span => #[repr(u16)] }), + U32 => ts.append_all(quote_spanned! { self.span => #[repr(u32)] }), + U64 => ts.append_all(quote_spanned! { self.span => #[repr(u64)] }), + U128 => ts.append_all(quote_spanned! { self.span => #[repr(u128)] }), + Usize => ts.append_all(quote_spanned! { self.span => #[repr(usize)] }), + I8 => ts.append_all(quote_spanned! { self.span => #[repr(i8)] }), + I16 => ts.append_all(quote_spanned! { self.span => #[repr(i16)] }), + I32 => ts.append_all(quote_spanned! { self.span => #[repr(i32)] }), + I64 => ts.append_all(quote_spanned! { self.span => #[repr(i64)] }), + I128 => ts.append_all(quote_spanned! { self.span => #[repr(i128)] }), + Isize => ts.append_all(quote_spanned! { self.span => #[repr(isize)] }), + } + } +} + +impl<Packed: With<NonZeroU32> + Copy> ToTokens for Spanned<AlignRepr<Packed>> { + fn to_tokens(&self, ts: &mut TokenStream) { + use AlignRepr::*; + // We use `syn::Index` instead of `u32` because `quote_spanned!` + // serializes `u32` literals as `123u32`, not just `123`. Rust doesn't + // recognize that as a valid argument to `#[repr(align(...))]` or + // `#[repr(packed(...))]`. + let to_index = |n: NonZeroU32| syn::Index { index: n.get(), span: self.span }; + match self.t { + Packed(n) => n.with(|n| { + let n = to_index(n); + ts.append_all(quote_spanned! { self.span => #[repr(packed(#n))] }) + }), + Align(n) => { + let n = to_index(n); + ts.append_all(quote_spanned! { self.span => #[repr(align(#n))] }) + } + } + } +} + +/// The result of parsing a single `#[repr(...)]` attribute or a single +/// directive inside a compound `#[repr(..., ...)]` attribute. +#[derive(Copy, Clone, PartialEq, Eq)] +#[cfg_attr(test, derive(Debug))] +pub(crate) enum RawRepr { + Transparent, + C, + Rust, + U8, + U16, + U32, + U64, + U128, + Usize, + I8, + I16, + I32, + I64, + I128, + Isize, + Align(NonZeroU32), + PackedN(NonZeroU32), + Packed, +} + +/// The error from converting from a `RawRepr`. +#[cfg_attr(test, derive(Debug, Eq, PartialEq))] +pub(crate) enum FromRawReprError<E> { + /// The `RawRepr` doesn't affect the high-level repr we're parsing (e.g. + /// it's `align(...)` and we're parsing a `CompoundRepr`). + None, + /// The `RawRepr` is invalid for the high-level repr we're parsing (e.g. + /// it's `packed` repr and we're parsing an `AlignRepr` for an enum type). + Err(E), +} + +/// The representation hint is not supported for the decorated type. +#[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] +pub(crate) struct UnsupportedReprError; + +impl<Prim: With<PrimitiveRepr>> TryFrom<RawRepr> for CompoundRepr<Prim> { + type Error = FromRawReprError<UnsupportedReprError>; + fn try_from( + raw: RawRepr, + ) -> Result<CompoundRepr<Prim>, FromRawReprError<UnsupportedReprError>> { + use RawRepr::*; + match raw { + C => Ok(CompoundRepr::C), + Rust => Ok(CompoundRepr::Rust), + raw @ (U8 | U16 | U32 | U64 | U128 | Usize | I8 | I16 | I32 | I64 | I128 | Isize) => { + Prim::try_with_or( + || match raw { + U8 => Ok(PrimitiveRepr::U8), + U16 => Ok(PrimitiveRepr::U16), + U32 => Ok(PrimitiveRepr::U32), + U64 => Ok(PrimitiveRepr::U64), + U128 => Ok(PrimitiveRepr::U128), + Usize => Ok(PrimitiveRepr::Usize), + I8 => Ok(PrimitiveRepr::I8), + I16 => Ok(PrimitiveRepr::I16), + I32 => Ok(PrimitiveRepr::I32), + I64 => Ok(PrimitiveRepr::I64), + I128 => Ok(PrimitiveRepr::I128), + Isize => Ok(PrimitiveRepr::Isize), + Transparent | C | Rust | Align(_) | PackedN(_) | Packed => { + Err(UnsupportedReprError) + } + }, + UnsupportedReprError, + ) + .map(CompoundRepr::Primitive) + .map_err(FromRawReprError::Err) + } + Transparent | Align(_) | PackedN(_) | Packed => Err(FromRawReprError::None), + } + } +} + +impl<Pcked: With<NonZeroU32>> TryFrom<RawRepr> for AlignRepr<Pcked> { + type Error = FromRawReprError<UnsupportedReprError>; + fn try_from(raw: RawRepr) -> Result<AlignRepr<Pcked>, FromRawReprError<UnsupportedReprError>> { + use RawRepr::*; + match raw { + Packed | PackedN(_) => Pcked::try_with_or( + || match raw { + Packed => Ok(NonZeroU32::new(1).unwrap()), + PackedN(n) => Ok(n), + U8 | U16 | U32 | U64 | U128 | Usize | I8 | I16 | I32 | I64 | I128 | Isize + | Transparent | C | Rust | Align(_) => Err(UnsupportedReprError), + }, + UnsupportedReprError, + ) + .map(AlignRepr::Packed) + .map_err(FromRawReprError::Err), + Align(n) => Ok(AlignRepr::Align(n)), + U8 | U16 | U32 | U64 | U128 | Usize | I8 | I16 | I32 | I64 | I128 | Isize + | Transparent | C | Rust => Err(FromRawReprError::None), + } + } +} + +/// The error from extracting a high-level repr type from a list of `RawRepr`s. +#[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] +enum FromRawReprsError<E> { + /// One of the `RawRepr`s is invalid for the high-level repr we're parsing + /// (e.g. there's a `packed` repr and we're parsing an `AlignRepr` for an + /// enum type). + Single(E), + /// Two `RawRepr`s appear which both affect the high-level repr we're + /// parsing (e.g., the list is `#[repr(align(2), packed)]`). Note that we + /// conservatively treat redundant reprs as conflicting (e.g. + /// `#[repr(packed, packed)]`). + Conflict, +} + +/// Tries to extract a high-level repr from a list of `RawRepr`s. +fn try_from_raw_reprs<'a, E, R: TryFrom<RawRepr, Error = FromRawReprError<E>>>( + r: impl IntoIterator<Item = &'a Spanned<RawRepr>>, +) -> Result<Option<Spanned<R>>, Spanned<FromRawReprsError<E>>> { + // Walk the list of `RawRepr`s and attempt to convert each to an `R`. Bail + // if we find any errors. If we find more than one which converts to an `R`, + // bail with a `Conflict` error. + r.into_iter().try_fold(None, |found: Option<Spanned<R>>, raw| { + let new = match Spanned::<R>::try_from(*raw) { + Ok(r) => r, + // This `RawRepr` doesn't convert to an `R`, so keep the current + // found `R`, if any. + Err(FromRawReprError::None) => return Ok(found), + // This repr is unsupported for the decorated type (e.g. + // `repr(packed)` on an enum). + Err(FromRawReprError::Err(Spanned { t: err, span })) => { + return Err(Spanned::new(FromRawReprsError::Single(err), span)) + } + }; + + if let Some(found) = found { + // We already found an `R`, but this `RawRepr` also converts to an + // `R`, so that's a conflict. + // + // `Span::join` returns `None` if the two spans are from different + // files or if we're not on the nightly compiler. In that case, just + // use `new`'s span. + let span = found.span.join(new.span).unwrap_or(new.span); + Err(Spanned::new(FromRawReprsError::Conflict, span)) + } else { + Ok(Some(new)) + } + }) +} + +/// The error returned from [`Repr::from_attrs`]. +#[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] +enum FromAttrsError { + FromRawReprs(FromRawReprsError<UnsupportedReprError>), + Unrecognized, +} + +impl From<FromRawReprsError<UnsupportedReprError>> for FromAttrsError { + fn from(err: FromRawReprsError<UnsupportedReprError>) -> FromAttrsError { + FromAttrsError::FromRawReprs(err) + } +} + +impl From<UnrecognizedReprError> for FromAttrsError { + fn from(_err: UnrecognizedReprError) -> FromAttrsError { + FromAttrsError::Unrecognized + } +} + +impl From<Spanned<FromAttrsError>> for Error { + fn from(err: Spanned<FromAttrsError>) -> Error { + let Spanned { t: err, span } = err; + match err { + FromAttrsError::FromRawReprs(FromRawReprsError::Single( + _err @ UnsupportedReprError, + )) => Error::new(span, "unsupported representation hint for the decorated type"), + FromAttrsError::FromRawReprs(FromRawReprsError::Conflict) => { + // NOTE: This says "another" rather than "a preceding" because + // when one of the reprs involved is `transparent`, we detect + // that condition in `Repr::from_attrs`, and at that point we + // can't tell which repr came first, so we might report this on + // the first involved repr rather than the second, third, etc. + Error::new(span, "this conflicts with another representation hint") + } + FromAttrsError::Unrecognized => Error::new(span, "unrecognized representation hint"), + } + } +} + +impl<Prim, Packed> Repr<Prim, Packed> { + fn from_attrs_inner(attrs: &[Attribute]) -> Result<Repr<Prim, Packed>, Spanned<FromAttrsError>> + where + Prim: With<PrimitiveRepr>, + Packed: With<NonZeroU32>, + { + let raw_reprs = RawRepr::from_attrs(attrs).map_err(Spanned::from)?; + + let transparent = { + let mut transparents = raw_reprs.iter().filter_map(|Spanned { t, span }| match t { + RawRepr::Transparent => Some(span), + _ => None, + }); + let first = transparents.next(); + let second = transparents.next(); + match (first, second) { + (None, None) => None, + (Some(span), None) => Some(*span), + (Some(_), Some(second)) => { + return Err(Spanned::new( + FromAttrsError::FromRawReprs(FromRawReprsError::Conflict), + *second, + )) + } + // An iterator can't produce a value only on the second call to + // `.next()`. + (None, Some(_)) => unreachable!(), + } + }; + + let compound: Option<Spanned<CompoundRepr<Prim>>> = + try_from_raw_reprs(raw_reprs.iter()).map_err(Spanned::from)?; + let align: Option<Spanned<AlignRepr<Packed>>> = + try_from_raw_reprs(raw_reprs.iter()).map_err(Spanned::from)?; + + if let Some(span) = transparent { + if compound.is_some() || align.is_some() { + // Arbitrarily report the problem on the `transparent` span. Any + // span will do. + return Err(Spanned::new(FromRawReprsError::Conflict.into(), span)); + } + + Ok(Repr::Transparent(span)) + } else { + Ok(Repr::Compound( + compound.unwrap_or(Spanned::new(CompoundRepr::Rust, Span::call_site())), + align, + )) + } + } +} + +impl<Prim, Packed> Repr<Prim, Packed> { + pub(crate) fn from_attrs(attrs: &[Attribute]) -> Result<Repr<Prim, Packed>, Error> + where + Prim: With<PrimitiveRepr>, + Packed: With<NonZeroU32>, + { + Repr::from_attrs_inner(attrs).map_err(Into::into) + } +} + +/// The representation hint could not be parsed or was unrecognized. +struct UnrecognizedReprError; + +impl RawRepr { + fn from_attrs( + attrs: &[Attribute], + ) -> Result<Vec<Spanned<RawRepr>>, Spanned<UnrecognizedReprError>> { + let mut reprs = Vec::new(); + for attr in attrs { + // Ignore documentation attributes. + if attr.path().is_ident("doc") { + continue; + } + if let Meta::List(ref meta_list) = attr.meta { + if meta_list.path.is_ident("repr") { + let parsed: Punctuated<Meta, Comma> = + match meta_list.parse_args_with(Punctuated::parse_terminated) { + Ok(parsed) => parsed, + Err(_) => { + return Err(Spanned::new( + UnrecognizedReprError, + meta_list.tokens.span(), + )) + } + }; + for meta in parsed { + let s = meta.span(); + reprs.push( + RawRepr::from_meta(&meta) + .map(|r| Spanned::new(r, s)) + .map_err(|e| Spanned::new(e, s))?, + ); + } + } + } + } + + Ok(reprs) + } + + fn from_meta(meta: &Meta) -> Result<RawRepr, UnrecognizedReprError> { + let (path, list) = match meta { + Meta::Path(path) => (path, None), + Meta::List(list) => (&list.path, Some(list)), + _ => return Err(UnrecognizedReprError), + }; + + let ident = path.get_ident().ok_or(UnrecognizedReprError)?; + + // Only returns `Ok` for non-zero power-of-two values. + let parse_nzu64 = |list: &MetaList| { + list.parse_args::<LitInt>() + .and_then(|int| int.base10_parse::<NonZeroU32>()) + .map_err(|_| UnrecognizedReprError) + .and_then(|nz| { + if nz.get().is_power_of_two() { + Ok(nz) + } else { + Err(UnrecognizedReprError) + } + }) + }; + + use RawRepr::*; + Ok(match (ident.to_string().as_str(), list) { + ("u8", None) => U8, + ("u16", None) => U16, + ("u32", None) => U32, + ("u64", None) => U64, + ("u128", None) => U128, + ("usize", None) => Usize, + ("i8", None) => I8, + ("i16", None) => I16, + ("i32", None) => I32, + ("i64", None) => I64, + ("i128", None) => I128, + ("isize", None) => Isize, + ("C", None) => C, + ("transparent", None) => Transparent, + ("Rust", None) => Rust, + ("packed", None) => Packed, + ("packed", Some(list)) => PackedN(parse_nzu64(list)?), + ("align", Some(list)) => Align(parse_nzu64(list)?), + _ => return Err(UnrecognizedReprError), + }) + } +} + +pub(crate) use util::*; +mod util { + use super::*; + /// A value with an associated span. + #[derive(Copy, Clone)] + #[cfg_attr(test, derive(Debug))] + pub(crate) struct Spanned<T> { + pub(crate) t: T, + pub(crate) span: Span, + } + + impl<T> Spanned<T> { + pub(super) fn new(t: T, span: Span) -> Spanned<T> { + Spanned { t, span } + } + + pub(super) fn from<U>(s: Spanned<U>) -> Spanned<T> + where + T: From<U>, + { + let Spanned { t: u, span } = s; + Spanned::new(u.into(), span) + } + + /// Delegates to `T: TryFrom`, preserving span information in both the + /// success and error cases. + pub(super) fn try_from<E, U>( + u: Spanned<U>, + ) -> Result<Spanned<T>, FromRawReprError<Spanned<E>>> + where + T: TryFrom<U, Error = FromRawReprError<E>>, + { + let Spanned { t: u, span } = u; + T::try_from(u).map(|t| Spanned { t, span }).map_err(|err| match err { + FromRawReprError::None => FromRawReprError::None, + FromRawReprError::Err(e) => FromRawReprError::Err(Spanned::new(e, span)), + }) + } + } + + // Used to permit implementing `With<T> for T: Inhabited` and for + // `Infallible` without a blanket impl conflict. + pub(crate) trait Inhabited {} + impl Inhabited for PrimitiveRepr {} + impl Inhabited for NonZeroU32 {} + + pub(crate) trait With<T> { + fn with<O, F: FnOnce(T) -> O>(self, f: F) -> O; + fn try_with_or<E, F: FnOnce() -> Result<T, E>>(f: F, err: E) -> Result<Self, E> + where + Self: Sized; + } + + impl<T: Inhabited> With<T> for T { + fn with<O, F: FnOnce(T) -> O>(self, f: F) -> O { + f(self) + } + + fn try_with_or<E, F: FnOnce() -> Result<T, E>>(f: F, _err: E) -> Result<Self, E> { + f() + } + } + + impl<T> With<T> for Infallible { + fn with<O, F: FnOnce(T) -> O>(self, _f: F) -> O { + match self {} + } + + fn try_with_or<E, F: FnOnce() -> Result<T, E>>(_f: F, err: E) -> Result<Self, E> { + Err(err) + } + } +} + +#[cfg(test)] +mod tests { + use syn::parse_quote; + + use super::*; + + impl<T> From<T> for Spanned<T> { + fn from(t: T) -> Spanned<T> { + Spanned::new(t, Span::call_site()) + } + } + + // We ignore spans for equality in testing since real spans are hard to + // synthesize and don't implement `PartialEq`. + impl<T: PartialEq> PartialEq for Spanned<T> { + fn eq(&self, other: &Spanned<T>) -> bool { + self.t.eq(&other.t) + } + } + + impl<T: Eq> Eq for Spanned<T> {} + + impl<Prim: PartialEq, Packed: PartialEq> PartialEq for Repr<Prim, Packed> { + fn eq(&self, other: &Repr<Prim, Packed>) -> bool { + match (self, other) { + (Repr::Transparent(_), Repr::Transparent(_)) => true, + (Repr::Compound(sc, sa), Repr::Compound(oc, oa)) => (sc, sa) == (oc, oa), + _ => false, + } + } + } + + fn s() -> Span { + Span::call_site() + } + + #[test] + fn test() { + // Test that a given `#[repr(...)]` attribute parses and returns the + // given `Repr` or error. + macro_rules! test { + ($(#[$attr:meta])* => $repr:expr) => { + test!(@inner $(#[$attr])* => Repr => Ok($repr)); + }; + // In the error case, the caller must explicitly provide the name of + // the `Repr` type to assist in type inference. + (@error $(#[$attr:meta])* => $typ:ident => $repr:expr) => { + test!(@inner $(#[$attr])* => $typ => Err($repr)); + }; + (@inner $(#[$attr:meta])* => $typ:ident => $repr:expr) => { + let attr: Attribute = parse_quote!($(#[$attr])*); + let mut got = $typ::from_attrs_inner(&[attr]); + let expect: Result<Repr<_, _>, _> = $repr; + if false { + // Force Rust to infer `got` as having the same type as + // `expect`. + got = expect; + } + assert_eq!(got, expect, stringify!($(#[$attr])*)); + }; + } + + use AlignRepr::*; + use CompoundRepr::*; + use PrimitiveRepr::*; + let nz = |n: u32| NonZeroU32::new(n).unwrap(); + + test!(#[repr(transparent)] => StructUnionRepr::Transparent(s())); + test!(#[repr()] => StructUnionRepr::Compound(Rust.into(), None)); + test!(#[repr(packed)] => StructUnionRepr::Compound(Rust.into(), Some(Packed(nz(1)).into()))); + test!(#[repr(packed(2))] => StructUnionRepr::Compound(Rust.into(), Some(Packed(nz(2)).into()))); + test!(#[repr(align(1))] => StructUnionRepr::Compound(Rust.into(), Some(Align(nz(1)).into()))); + test!(#[repr(align(2))] => StructUnionRepr::Compound(Rust.into(), Some(Align(nz(2)).into()))); + test!(#[repr(C)] => StructUnionRepr::Compound(C.into(), None)); + test!(#[repr(C, packed)] => StructUnionRepr::Compound(C.into(), Some(Packed(nz(1)).into()))); + test!(#[repr(C, packed(2))] => StructUnionRepr::Compound(C.into(), Some(Packed(nz(2)).into()))); + test!(#[repr(C, align(1))] => StructUnionRepr::Compound(C.into(), Some(Align(nz(1)).into()))); + test!(#[repr(C, align(2))] => StructUnionRepr::Compound(C.into(), Some(Align(nz(2)).into()))); + + test!(#[repr(transparent)] => EnumRepr::Transparent(s())); + test!(#[repr()] => EnumRepr::Compound(Rust.into(), None)); + test!(#[repr(align(1))] => EnumRepr::Compound(Rust.into(), Some(Align(nz(1)).into()))); + test!(#[repr(align(2))] => EnumRepr::Compound(Rust.into(), Some(Align(nz(2)).into()))); + + macro_rules! for_each_compound_repr { + ($($r:tt => $var:expr),*) => { + $( + test!(#[repr($r)] => EnumRepr::Compound($var.into(), None)); + test!(#[repr($r, align(1))] => EnumRepr::Compound($var.into(), Some(Align(nz(1)).into()))); + test!(#[repr($r, align(2))] => EnumRepr::Compound($var.into(), Some(Align(nz(2)).into()))); + )* + } + } + + for_each_compound_repr!( + C => C, + u8 => Primitive(U8), + u16 => Primitive(U16), + u32 => Primitive(U32), + u64 => Primitive(U64), + usize => Primitive(Usize), + i8 => Primitive(I8), + i16 => Primitive(I16), + i32 => Primitive(I32), + i64 => Primitive(I64), + isize => Primitive(Isize) + ); + + use FromAttrsError::*; + use FromRawReprsError::*; + + // Run failure tests which are valid for both `StructUnionRepr` and + // `EnumRepr`. + macro_rules! for_each_repr_type { + ($($repr:ident),*) => { + $( + // Invalid packed or align attributes + test!(@error #[repr(packed(0))] => $repr => Unrecognized.into()); + test!(@error #[repr(packed(3))] => $repr => Unrecognized.into()); + test!(@error #[repr(align(0))] => $repr => Unrecognized.into()); + test!(@error #[repr(align(3))] => $repr => Unrecognized.into()); + + // Conflicts + test!(@error #[repr(transparent, transparent)] => $repr => FromRawReprs(Conflict).into()); + test!(@error #[repr(transparent, C)] => $repr => FromRawReprs(Conflict).into()); + test!(@error #[repr(transparent, Rust)] => $repr => FromRawReprs(Conflict).into()); + + test!(@error #[repr(C, transparent)] => $repr => FromRawReprs(Conflict).into()); + test!(@error #[repr(C, C)] => $repr => FromRawReprs(Conflict).into()); + test!(@error #[repr(C, Rust)] => $repr => FromRawReprs(Conflict).into()); + + test!(@error #[repr(Rust, transparent)] => $repr => FromRawReprs(Conflict).into()); + test!(@error #[repr(Rust, C)] => $repr => FromRawReprs(Conflict).into()); + test!(@error #[repr(Rust, Rust)] => $repr => FromRawReprs(Conflict).into()); + )* + } + } + + for_each_repr_type!(StructUnionRepr, EnumRepr); + + // Enum-specific conflicts. + // + // We don't bother to test every combination since that would be a huge + // number (enums can have primitive reprs u8, u16, u32, u64, usize, i8, + // i16, i32, i64, and isize). Instead, since the conflict logic doesn't + // care what specific value of `PrimitiveRepr` is present, we assume + // that testing against u8 alone is fine. + test!(@error #[repr(transparent, u8)] => EnumRepr => FromRawReprs(Conflict).into()); + test!(@error #[repr(u8, transparent)] => EnumRepr => FromRawReprs(Conflict).into()); + test!(@error #[repr(C, u8)] => EnumRepr => FromRawReprs(Conflict).into()); + test!(@error #[repr(u8, C)] => EnumRepr => FromRawReprs(Conflict).into()); + test!(@error #[repr(Rust, u8)] => EnumRepr => FromRawReprs(Conflict).into()); + test!(@error #[repr(u8, Rust)] => EnumRepr => FromRawReprs(Conflict).into()); + test!(@error #[repr(u8, u8)] => EnumRepr => FromRawReprs(Conflict).into()); + + // Illegal struct/union reprs + test!(@error #[repr(u8)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(u16)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(u32)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(u64)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(usize)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(i8)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(i16)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(i32)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(i64)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(isize)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + + // Illegal enum reprs + test!(@error #[repr(packed)] => EnumRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(packed(1))] => EnumRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + test!(@error #[repr(packed(2))] => EnumRepr => FromRawReprs(Single(UnsupportedReprError)).into()); + } +} |