diff options
| -rw-r--r-- | rust/Cargo.lock | 7 | ||||
| -rw-r--r-- | rust/Cargo.toml | 1 | ||||
| -rw-r--r-- | rust/bits/Cargo.toml | 19 | ||||
| -rw-r--r-- | rust/bits/meson.build | 16 | ||||
| -rw-r--r-- | rust/bits/src/lib.rs | 443 | ||||
| -rw-r--r-- | rust/meson.build | 1 | ||||
| -rw-r--r-- | rust/qemu-api-macros/src/bits.rs | 229 | ||||
| -rw-r--r-- | rust/qemu-api-macros/src/lib.rs | 12 |
8 files changed, 728 insertions, 0 deletions
diff --git a/rust/Cargo.lock b/rust/Cargo.lock index 13d580c693..0dfe0fb6ce 100644 --- a/rust/Cargo.lock +++ b/rust/Cargo.lock @@ -32,6 +32,13 @@ dependencies = [ ] [[package]] +name = "bits" +version = "0.1.0" +dependencies = [ + "qemu_api_macros", +] + +[[package]] name = "either" version = "1.12.0" source = "registry+https://github.com/rust-lang/crates.io-index" diff --git a/rust/Cargo.toml b/rust/Cargo.toml index a00b8ad0bc..fd4c2fbf84 100644 --- a/rust/Cargo.toml +++ b/rust/Cargo.toml @@ -1,6 +1,7 @@ [workspace] resolver = "2" members = [ + "bits", "qemu-api-macros", "qemu-api", "hw/char/pl011", diff --git a/rust/bits/Cargo.toml b/rust/bits/Cargo.toml new file mode 100644 index 0000000000..1ff38a4117 --- /dev/null +++ b/rust/bits/Cargo.toml @@ -0,0 +1,19 @@ +[package] +name = "bits" +version = "0.1.0" +authors = ["Paolo Bonzini <pbonzini@redhat.com>"] +description = "const-friendly bit flags" +resolver = "2" +publish = false + +edition.workspace = true +homepage.workspace = true +license.workspace = true +repository.workspace = true +rust-version.workspace = true + +[dependencies] +qemu_api_macros = { path = "../qemu-api-macros" } + +[lints] +workspace = true diff --git a/rust/bits/meson.build b/rust/bits/meson.build new file mode 100644 index 0000000000..2a41e138c5 --- /dev/null +++ b/rust/bits/meson.build @@ -0,0 +1,16 @@ +_bits_rs = static_library( + 'bits', + 'src/lib.rs', + override_options: ['rust_std=2021', 'build.rust_std=2021'], + rust_abi: 'rust', + dependencies: [qemu_api_macros], +) + +bits_rs = declare_dependency(link_with: _bits_rs) + +rust.test('rust-bits-tests', _bits_rs, + suite: ['unit', 'rust']) + +rust.doctest('rust-bits-doctests', _bits_rs, + dependencies: bits_rs, + suite: ['doc', 'rust']) diff --git a/rust/bits/src/lib.rs b/rust/bits/src/lib.rs new file mode 100644 index 0000000000..d485d6bd11 --- /dev/null +++ b/rust/bits/src/lib.rs @@ -0,0 +1,443 @@ +// SPDX-License-Identifier: MIT or Apache-2.0 or GPL-2.0-or-later + +/// # Definition entry point +/// +/// Define a struct with a single field of type $type. Include public constants +/// for each element listed in braces. +/// +/// The unnamed element at the end, if present, can be used to enlarge the set +/// of valid bits. Bits that are valid but not listed are treated normally for +/// the purpose of arithmetic operations, and are printed with their hexadecimal +/// value. +/// +/// The struct implements the following traits: [`BitAnd`](std::ops::BitAnd), +/// [`BitOr`](std::ops::BitOr), [`BitXor`](std::ops::BitXor), +/// [`Not`](std::ops::Not), [`Sub`](std::ops::Sub); [`Debug`](std::fmt::Debug), +/// [`Display`](std::fmt::Display), [`Binary`](std::fmt::Binary), +/// [`Octal`](std::fmt::Octal), [`LowerHex`](std::fmt::LowerHex), +/// [`UpperHex`](std::fmt::UpperHex); [`From`]`<type>`/[`Into`]`<type>` where +/// type is the type specified in the definition. +/// +/// ## Example +/// +/// ``` +/// # use bits::bits; +/// bits! { +/// pub struct Colors(u8) { +/// BLACK = 0, +/// RED = 1, +/// GREEN = 1 << 1, +/// BLUE = 1 << 2, +/// WHITE = (1 << 0) | (1 << 1) | (1 << 2), +/// } +/// } +/// ``` +/// +/// ``` +/// # use bits::bits; +/// # bits! { pub struct Colors(u8) { BLACK = 0, RED = 1, GREEN = 1 << 1, BLUE = 1 << 2, } } +/// +/// bits! { +/// pub struct Colors8(u8) { +/// BLACK = 0, +/// RED = 1, +/// GREEN = 1 << 1, +/// BLUE = 1 << 2, +/// WHITE = (1 << 0) | (1 << 1) | (1 << 2), +/// +/// _ = 255, +/// } +/// } +/// +/// // The previously defined struct ignores bits not explicitly defined. +/// assert_eq!( +/// Colors::from(255).into_bits(), +/// (Colors::RED | Colors::GREEN | Colors::BLUE).into_bits() +/// ); +/// +/// // Adding "_ = 255" makes it retain other bits as well. +/// assert_eq!(Colors8::from(255).into_bits(), 255); +/// +/// // all() does not include the additional bits, valid_bits() does +/// assert_eq!(Colors8::all().into_bits(), Colors::all().into_bits()); +/// assert_eq!(Colors8::valid_bits().into_bits(), 255); +/// ``` +/// +/// # Evaluation entry point +/// +/// Return a constant corresponding to the boolean expression `$expr`. +/// Identifiers in the expression correspond to values defined for the +/// type `$type`. Supported operators are `!` (unary), `-`, `&`, `^`, `|`. +/// +/// ## Examples +/// +/// ``` +/// # use bits::bits; +/// bits! { +/// pub struct Colors(u8) { +/// BLACK = 0, +/// RED = 1, +/// GREEN = 1 << 1, +/// BLUE = 1 << 2, +/// // same as "WHITE = 7", +/// WHITE = bits!(Self as u8: RED | GREEN | BLUE), +/// } +/// } +/// +/// let rgb = bits! { Colors: RED | GREEN | BLUE }; +/// assert_eq!(rgb, Colors::WHITE); +/// ``` +#[macro_export] +macro_rules! bits { + { + $(#[$struct_meta:meta])* + $struct_vis:vis struct $struct_name:ident($field_vis:vis $type:ty) { + $($(#[$const_meta:meta])* $const:ident = $val:expr),+ + $(,_ = $mask:expr)? + $(,)? + } + } => { + $(#[$struct_meta])* + #[derive(Clone, Copy, PartialEq, Eq)] + #[repr(transparent)] + $struct_vis struct $struct_name($field_vis $type); + + impl $struct_name { + $( #[allow(dead_code)] $(#[$const_meta])* + pub const $const: $struct_name = $struct_name($val); )+ + + #[doc(hidden)] + const VALID__: $type = $( Self::$const.0 )|+ $(|$mask)?; + + #[allow(dead_code)] + #[inline(always)] + pub const fn empty() -> Self { + Self(0) + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn all() -> Self { + Self($( Self::$const.0 )|+) + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn valid_bits() -> Self { + Self(Self::VALID__) + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn valid(val: $type) -> bool { + (val & !Self::VALID__) == 0 + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn any_set(self, mask: Self) -> bool { + (self.0 & mask.0) != 0 + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn all_set(self, mask: Self) -> bool { + (self.0 & mask.0) == mask.0 + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn none_set(self, mask: Self) -> bool { + (self.0 & mask.0) == 0 + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn from_bits(value: $type) -> Self { + $struct_name(value) + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn into_bits(self) -> $type { + self.0 + } + + #[allow(dead_code)] + #[inline(always)] + pub fn set(&mut self, rhs: Self) { + self.0 |= rhs.0; + } + + #[allow(dead_code)] + #[inline(always)] + pub fn clear(&mut self, rhs: Self) { + self.0 &= !rhs.0; + } + + #[allow(dead_code)] + #[inline(always)] + pub fn toggle(&mut self, rhs: Self) { + self.0 ^= rhs.0; + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn intersection(self, rhs: Self) -> Self { + $struct_name(self.0 & rhs.0) + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn difference(self, rhs: Self) -> Self { + $struct_name(self.0 & !rhs.0) + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn symmetric_difference(self, rhs: Self) -> Self { + $struct_name(self.0 ^ rhs.0) + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn union(self, rhs: Self) -> Self { + $struct_name(self.0 | rhs.0) + } + + #[allow(dead_code)] + #[inline(always)] + pub const fn invert(self) -> Self { + $struct_name(self.0 ^ Self::VALID__) + } + } + + impl ::std::fmt::Binary for $struct_name { + fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result { + // If no width, use the highest valid bit + let width = f.width().unwrap_or((Self::VALID__.ilog2() + 1) as usize); + write!(f, "{:0>width$.precision$b}", self.0, + width = width, + precision = f.precision().unwrap_or(width)) + } + } + + impl ::std::fmt::LowerHex for $struct_name { + fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result { + <$type as ::std::fmt::LowerHex>::fmt(&self.0, f) + } + } + + impl ::std::fmt::Octal for $struct_name { + fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result { + <$type as ::std::fmt::Octal>::fmt(&self.0, f) + } + } + + impl ::std::fmt::UpperHex for $struct_name { + fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result { + <$type as ::std::fmt::UpperHex>::fmt(&self.0, f) + } + } + + impl ::std::fmt::Debug for $struct_name { + fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result { + write!(f, "{}({})", stringify!($struct_name), self) + } + } + + impl ::std::fmt::Display for $struct_name { + fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result { + use ::std::fmt::Display; + let mut first = true; + let mut left = self.0; + $(if Self::$const.0.is_power_of_two() && (self & Self::$const).0 != 0 { + if first { first = false } else { Display::fmt(&'|', f)?; } + Display::fmt(stringify!($const), f)?; + left -= Self::$const.0; + })+ + if first { + Display::fmt(&'0', f) + } else if left != 0 { + write!(f, "|{left:#x}") + } else { + Ok(()) + } + } + } + + impl ::std::cmp::PartialEq<$type> for $struct_name { + fn eq(&self, rhs: &$type) -> bool { + self.0 == *rhs + } + } + + impl ::std::ops::BitAnd<$struct_name> for &$struct_name { + type Output = $struct_name; + fn bitand(self, rhs: $struct_name) -> Self::Output { + $struct_name(self.0 & rhs.0) + } + } + + impl ::std::ops::BitAndAssign<$struct_name> for $struct_name { + fn bitand_assign(&mut self, rhs: $struct_name) { + self.0 = self.0 & rhs.0 + } + } + + impl ::std::ops::BitXor<$struct_name> for &$struct_name { + type Output = $struct_name; + fn bitxor(self, rhs: $struct_name) -> Self::Output { + $struct_name(self.0 ^ rhs.0) + } + } + + impl ::std::ops::BitXorAssign<$struct_name> for $struct_name { + fn bitxor_assign(&mut self, rhs: $struct_name) { + self.0 = self.0 ^ rhs.0 + } + } + + impl ::std::ops::BitOr<$struct_name> for &$struct_name { + type Output = $struct_name; + fn bitor(self, rhs: $struct_name) -> Self::Output { + $struct_name(self.0 | rhs.0) + } + } + + impl ::std::ops::BitOrAssign<$struct_name> for $struct_name { + fn bitor_assign(&mut self, rhs: $struct_name) { + self.0 = self.0 | rhs.0 + } + } + + impl ::std::ops::Sub<$struct_name> for &$struct_name { + type Output = $struct_name; + fn sub(self, rhs: $struct_name) -> Self::Output { + $struct_name(self.0 & !rhs.0) + } + } + + impl ::std::ops::SubAssign<$struct_name> for $struct_name { + fn sub_assign(&mut self, rhs: $struct_name) { + self.0 = self.0 - rhs.0 + } + } + + impl ::std::ops::Not for &$struct_name { + type Output = $struct_name; + fn not(self) -> Self::Output { + $struct_name(self.0 ^ $struct_name::VALID__) + } + } + + impl ::std::ops::BitAnd<$struct_name> for $struct_name { + type Output = Self; + fn bitand(self, rhs: Self) -> Self::Output { + $struct_name(self.0 & rhs.0) + } + } + + impl ::std::ops::BitXor<$struct_name> for $struct_name { + type Output = Self; + fn bitxor(self, rhs: Self) -> Self::Output { + $struct_name(self.0 ^ rhs.0) + } + } + + impl ::std::ops::BitOr<$struct_name> for $struct_name { + type Output = Self; + fn bitor(self, rhs: Self) -> Self::Output { + $struct_name(self.0 | rhs.0) + } + } + + impl ::std::ops::Sub<$struct_name> for $struct_name { + type Output = Self; + fn sub(self, rhs: Self) -> Self::Output { + $struct_name(self.0 & !rhs.0) + } + } + + impl ::std::ops::Not for $struct_name { + type Output = Self; + fn not(self) -> Self::Output { + $struct_name(self.0 ^ Self::VALID__) + } + } + + impl From<$struct_name> for $type { + fn from(x: $struct_name) -> $type { + x.0 + } + } + + impl From<$type> for $struct_name { + fn from(x: $type) -> Self { + $struct_name(x & Self::VALID__) + } + } + }; + + { $type:ty: $expr:expr } => { + ::qemu_api_macros::bits_const_internal! { $type @ ($expr) } + }; + + { $type:ty as $int_type:ty: $expr:expr } => { + (::qemu_api_macros::bits_const_internal! { $type @ ($expr) }.into_bits()) as $int_type + }; +} + +#[cfg(test)] +mod test { + bits! { + pub struct InterruptMask(u32) { + OE = 1 << 10, + BE = 1 << 9, + PE = 1 << 8, + FE = 1 << 7, + RT = 1 << 6, + TX = 1 << 5, + RX = 1 << 4, + DSR = 1 << 3, + DCD = 1 << 2, + CTS = 1 << 1, + RI = 1 << 0, + + E = bits!(Self as u32: OE | BE | PE | FE), + MS = bits!(Self as u32: RI | DSR | DCD | CTS), + } + } + + #[test] + pub fn test_not() { + assert_eq!( + !InterruptMask::from(InterruptMask::RT.0), + InterruptMask::E | InterruptMask::MS | InterruptMask::TX | InterruptMask::RX + ); + } + + #[test] + pub fn test_and() { + assert_eq!( + InterruptMask::from(0), + InterruptMask::MS & InterruptMask::OE + ) + } + + #[test] + pub fn test_or() { + assert_eq!( + InterruptMask::E, + InterruptMask::OE | InterruptMask::BE | InterruptMask::PE | InterruptMask::FE + ); + } + + #[test] + pub fn test_xor() { + assert_eq!( + InterruptMask::E ^ InterruptMask::BE, + InterruptMask::OE | InterruptMask::PE | InterruptMask::FE + ); + } +} diff --git a/rust/meson.build b/rust/meson.build index afce62f477..b1b3315be9 100644 --- a/rust/meson.build +++ b/rust/meson.build @@ -17,6 +17,7 @@ proc_macro2_rs_native = dependency('proc-macro2-1-rs', native: true) qemuutil_rs = qemuutil.partial_dependency(link_args: true, links: true) subdir('qemu-api-macros') +subdir('bits') subdir('qemu-api') subdir('hw') diff --git a/rust/qemu-api-macros/src/bits.rs b/rust/qemu-api-macros/src/bits.rs new file mode 100644 index 0000000000..5ba84757ee --- /dev/null +++ b/rust/qemu-api-macros/src/bits.rs @@ -0,0 +1,229 @@ +// SPDX-License-Identifier: MIT or Apache-2.0 or GPL-2.0-or-later + +// shadowing is useful together with "if let" +#![allow(clippy::shadow_unrelated)] + +use proc_macro2::{ + Delimiter, Group, Ident, Punct, Spacing, Span, TokenStream, TokenTree, TokenTree as TT, +}; + +use crate::utils::MacroError; + +pub struct BitsConstInternal { + typ: TokenTree, +} + +fn paren(ts: TokenStream) -> TokenTree { + TT::Group(Group::new(Delimiter::Parenthesis, ts)) +} + +fn ident(s: &'static str) -> TokenTree { + TT::Ident(Ident::new(s, Span::call_site())) +} + +fn punct(ch: char) -> TokenTree { + TT::Punct(Punct::new(ch, Spacing::Alone)) +} + +/// Implements a recursive-descent parser that translates Boolean expressions on +/// bitmasks to invocations of `const` functions defined by the `bits!` macro. +impl BitsConstInternal { + // primary ::= '(' or ')' + // | ident + // | '!' ident + fn parse_primary( + &self, + tok: TokenTree, + it: &mut dyn Iterator<Item = TokenTree>, + out: &mut TokenStream, + ) -> Result<Option<TokenTree>, MacroError> { + let next = match tok { + TT::Group(ref g) => { + if g.delimiter() != Delimiter::Parenthesis && g.delimiter() != Delimiter::None { + return Err(MacroError::Message("expected parenthesis".into(), g.span())); + } + let mut stream = g.stream().into_iter(); + let Some(first_tok) = stream.next() else { + return Err(MacroError::Message( + "expected operand, found ')'".into(), + g.span(), + )); + }; + let mut output = TokenStream::new(); + // start from the lowest precedence + let next = self.parse_or(first_tok, &mut stream, &mut output)?; + if let Some(tok) = next { + return Err(MacroError::Message( + format!("unexpected token {tok}"), + tok.span(), + )); + } + out.extend(Some(paren(output))); + it.next() + } + TT::Ident(_) => { + let mut output = TokenStream::new(); + output.extend([ + self.typ.clone(), + TT::Punct(Punct::new(':', Spacing::Joint)), + TT::Punct(Punct::new(':', Spacing::Joint)), + tok, + ]); + out.extend(Some(paren(output))); + it.next() + } + TT::Punct(ref p) => { + if p.as_char() != '!' { + return Err(MacroError::Message("expected operand".into(), p.span())); + } + let Some(rhs_tok) = it.next() else { + return Err(MacroError::Message( + "expected operand at end of input".into(), + p.span(), + )); + }; + let next = self.parse_primary(rhs_tok, it, out)?; + out.extend([punct('.'), ident("invert"), paren(TokenStream::new())]); + next + } + _ => { + return Err(MacroError::Message("unexpected literal".into(), tok.span())); + } + }; + Ok(next) + } + + fn parse_binop< + F: Fn( + &Self, + TokenTree, + &mut dyn Iterator<Item = TokenTree>, + &mut TokenStream, + ) -> Result<Option<TokenTree>, MacroError>, + >( + &self, + tok: TokenTree, + it: &mut dyn Iterator<Item = TokenTree>, + out: &mut TokenStream, + ch: char, + f: F, + method: &'static str, + ) -> Result<Option<TokenTree>, MacroError> { + let mut next = f(self, tok, it, out)?; + while next.is_some() { + let op = next.as_ref().unwrap(); + let TT::Punct(ref p) = op else { break }; + if p.as_char() != ch { + break; + } + + let Some(rhs_tok) = it.next() else { + return Err(MacroError::Message( + "expected operand at end of input".into(), + p.span(), + )); + }; + let mut rhs = TokenStream::new(); + next = f(self, rhs_tok, it, &mut rhs)?; + out.extend([punct('.'), ident(method), paren(rhs)]); + } + Ok(next) + } + + // sub ::= primary ('-' primary)* + pub fn parse_sub( + &self, + tok: TokenTree, + it: &mut dyn Iterator<Item = TokenTree>, + out: &mut TokenStream, + ) -> Result<Option<TokenTree>, MacroError> { + self.parse_binop(tok, it, out, '-', Self::parse_primary, "difference") + } + + // and ::= sub ('&' sub)* + fn parse_and( + &self, + tok: TokenTree, + it: &mut dyn Iterator<Item = TokenTree>, + out: &mut TokenStream, + ) -> Result<Option<TokenTree>, MacroError> { + self.parse_binop(tok, it, out, '&', Self::parse_sub, "intersection") + } + + // xor ::= and ('&' and)* + fn parse_xor( + &self, + tok: TokenTree, + it: &mut dyn Iterator<Item = TokenTree>, + out: &mut TokenStream, + ) -> Result<Option<TokenTree>, MacroError> { + self.parse_binop(tok, it, out, '^', Self::parse_and, "symmetric_difference") + } + + // or ::= xor ('|' xor)* + pub fn parse_or( + &self, + tok: TokenTree, + it: &mut dyn Iterator<Item = TokenTree>, + out: &mut TokenStream, + ) -> Result<Option<TokenTree>, MacroError> { + self.parse_binop(tok, it, out, '|', Self::parse_xor, "union") + } + + pub fn parse( + it: &mut dyn Iterator<Item = TokenTree>, + ) -> Result<proc_macro2::TokenStream, MacroError> { + let mut pos = Span::call_site(); + let mut typ = proc_macro2::TokenStream::new(); + + // Gobble everything up to an `@` sign, which is followed by a + // parenthesized expression; that is, all token trees except the + // last two form the type. + let next = loop { + let tok = it.next(); + if let Some(ref t) = tok { + pos = t.span(); + } + match tok { + None => break None, + Some(TT::Punct(ref p)) if p.as_char() == '@' => { + let tok = it.next(); + if let Some(ref t) = tok { + pos = t.span(); + } + break tok; + } + Some(x) => typ.extend(Some(x)), + } + }; + + let Some(tok) = next else { + return Err(MacroError::Message( + "expected expression, do not call this macro directly".into(), + pos, + )); + }; + let TT::Group(ref _group) = tok else { + return Err(MacroError::Message( + "expected parenthesis, do not call this macro directly".into(), + tok.span(), + )); + }; + let mut out = TokenStream::new(); + let state = Self { + typ: TT::Group(Group::new(Delimiter::None, typ)), + }; + + let next = state.parse_primary(tok, it, &mut out)?; + + // A parenthesized expression is a single production of the grammar, + // so the input must have reached the last token. + if let Some(tok) = next { + return Err(MacroError::Message( + format!("unexpected token {tok}"), + tok.span(), + )); + } + Ok(out) + } +} diff --git a/rust/qemu-api-macros/src/lib.rs b/rust/qemu-api-macros/src/lib.rs index f97449bb30..ceb79f09f9 100644 --- a/rust/qemu-api-macros/src/lib.rs +++ b/rust/qemu-api-macros/src/lib.rs @@ -12,6 +12,9 @@ use syn::{ mod utils; use utils::MacroError; +mod bits; +use bits::BitsConstInternal; + fn get_fields<'a>( input: &'a DeriveInput, msg: &str, @@ -219,3 +222,12 @@ pub fn derive_tryinto(input: TokenStream) -> TokenStream { TokenStream::from(expanded) } + +#[proc_macro] +pub fn bits_const_internal(ts: TokenStream) -> TokenStream { + let ts = proc_macro2::TokenStream::from(ts); + let mut it = ts.into_iter(); + + let expanded = BitsConstInternal::parse(&mut it).unwrap_or_else(Into::into); + TokenStream::from(expanded) +} |