Files
nix-js/fix-ir/src/lib.rs
T

329 lines
8.5 KiB
Rust

use std::hash::Hash;
use std::marker::PhantomData;
use bumpalo::Bump;
use bumpalo::collections::Vec;
use fix_builtins::{BUILTINS, BuiltinId};
use fix_common::StringId;
use ghost_cell::{GhostCell, GhostToken};
use num_enum::TryFromPrimitive as _;
use rnix::{TextRange, ast};
use string_interner::DefaultStringInterner;
pub mod downgrade;
pub type HashMap<'ir, K, V> = hashbrown::HashMap<K, V, hashbrown::DefaultHashBuilder, &'ir Bump>;
pub type IrRef<'id, 'ir> = <GhostRef<'id, 'ir> as RefExt<'ir>>::IrRef;
pub type RawIrRef<'ir> = <RawRef<'ir> as RefExt<'ir>>::IrRef;
pub type GhostMaybeThunkRef<'id, 'ir> = <GhostRef<'id, 'ir> as RefExt<'ir>>::MaybeThunkRef;
impl<'id, 'ir> Ir<'ir, GhostRef<'id, 'ir>> {
/// Freeze a mutable IR reference into a read-only one, consuming the
/// `GhostToken` to prevent any further mutation.
pub fn freeze(this: IrRef<'id, 'ir>, _: GhostToken<'id>) -> RawIrRef<'ir> {
// SAFETY: The transmute is sound because:
// - `GhostCell<'id, T>` is `#[repr(transparent)]` over `T`, so
// `&'ir GhostCell<'id, T>` and `&'ir T` have identical layout.
// - `Ir<'ir, R>` is `#[repr(C)]`, and for every field that depends on
// `R`, instantiating `R = GhostRef<'id, 'ir>` vs `R = RawRef<'ir>`
// produces types of identical layout:
// - `R::IrRef` becomes `&'ir GhostCell<'id, Ir<...>>` vs `&'ir Ir<...>`
// - `R::MaybeThunkRef` becomes `&'ir GhostCell<'id, MaybeThunk>`
// vs `&'ir MaybeThunk`
// - `R::Ref<Ir<'ir, R>>` (used in `ConcatStrings::parts`) reduces
// to the same case as `R::IrRef`
// - Therefore `IrRef<'id, 'ir>` and `RawIrRef<'ir>` are both
// pointer-sized references with the same layout.
//
// Consuming the `GhostToken` guarantees no `borrow_mut` calls can
// occur afterwards, so the shared `&Ir` references reachable from a
// `RawIrRef<'ir>` can never alias with mutable references.
unsafe { std::mem::transmute::<IrRef<'id, 'ir>, RawIrRef<'ir>>(this) }
}
}
#[repr(C)]
#[derive(Debug, Clone, Copy)]
pub enum MaybeThunk {
Int(i64),
Float(f64),
Bool(bool),
Null,
Str(StringId),
Path(StringId),
Thunk(ThunkId),
Arg { layer: u8 },
Builtin(BuiltinId),
Builtins,
ReplBinding(StringId),
ScopedImportBinding(StringId),
WithLookup(StringId),
}
pub trait Ref<'ir> {
type Ref<T>
where
T: 'ir;
}
pub trait RefExt<'ir>: Ref<'ir> {
type Ir;
type IrRef;
type MaybeThunkRef;
}
impl<'ir, T: Ref<'ir> + 'ir> RefExt<'ir> for T {
type Ir = Ir<'ir, Self>;
type IrRef = Self::Ref<Self::Ir>;
type MaybeThunkRef = Self::Ref<MaybeThunk>;
}
pub struct GhostRef<'id, 'ir>(PhantomData<&'ir GhostCell<'id, ()>>);
pub struct RawRef<'ir>(PhantomData<&'ir ()>);
impl<'id, 'ir> Ref<'ir> for GhostRef<'id, 'ir> {
type Ref<T: 'ir> = &'ir GhostCell<'id, T>;
}
impl<'ir> Ref<'ir> for RawRef<'ir> {
type Ref<T: 'ir> = &'ir T;
}
#[repr(C)]
#[derive(Debug)]
pub enum Ir<'ir, R: RefExt<'ir> + ?Sized + 'ir> {
Int(i64),
Float(f64),
Bool(bool),
Null,
Str(StringId),
Path(R::IrRef),
AttrSet {
stcs: HashMap<'ir, StringId, (R::MaybeThunkRef, TextRange)>,
dyns: Vec<'ir, (R::IrRef, R::MaybeThunkRef, TextRange)>,
},
List {
items: Vec<'ir, R::MaybeThunkRef>,
},
ConcatStrings {
parts: Vec<'ir, R::Ref<Ir<'ir, R>>>,
force_string: bool,
},
// OPs
UnOp {
rhs: R::IrRef,
kind: UnOpKind,
},
BinOp {
lhs: R::IrRef,
rhs: R::IrRef,
kind: BinOpKind,
},
HasAttr {
lhs: R::IrRef,
rhs: Vec<'ir, Attr<R::IrRef>>,
},
Select {
expr: R::IrRef,
attrpath: Vec<'ir, Attr<R::IrRef>>,
default: Option<R::IrRef>,
span: TextRange,
},
// Conditionals
If {
cond: R::IrRef,
consq: R::IrRef,
alter: R::IrRef,
},
Assert {
assertion: R::IrRef,
expr: R::IrRef,
assertion_raw: String,
span: TextRange,
},
With {
namespace: R::MaybeThunkRef,
body: R::IrRef,
thunks: Vec<'ir, (ThunkId, R::IrRef)>,
},
WithLookup(StringId),
// Function related
Func {
body: R::IrRef,
param: Option<Param<'ir>>,
thunks: Vec<'ir, (ThunkId, R::IrRef)>,
},
Arg {
layer: u8,
},
Call {
func: R::IrRef,
arg: R::MaybeThunkRef,
span: TextRange,
},
// Builtins
Builtins,
Builtin(BuiltinId),
BuiltinConst(StringId),
// Misc
TopLevel {
body: R::IrRef,
thunks: Vec<'ir, (ThunkId, R::IrRef)>,
},
MaybeThunk(R::MaybeThunkRef),
CurPos(TextRange),
ReplBinding(StringId),
ScopedImportBinding(StringId),
}
#[repr(transparent)]
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct ThunkId(pub usize);
#[repr(transparent)]
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct SpanId(pub u32);
/// Represents a key in an attribute path.
#[allow(unused)]
#[derive(Debug)]
pub enum Attr<Ref> {
/// A dynamic attribute key, which is an expression that must evaluate to a string.
/// Example: `attrs.${key}`
Dynamic(Ref, TextRange),
/// A static attribute key.
/// Example: `attrs.key`
Str(StringId, TextRange),
}
/// The kinds of binary operations supported in Nix.
#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
pub enum BinOpKind {
// Arithmetic
Add,
Sub,
Div,
Mul,
// Comparison
Eq,
Neq,
Lt,
Gt,
Leq,
Geq,
// Logical
And,
Or,
Impl,
// Set/String/Path operations
Con, // List concatenation (`++`)
Upd, // AttrSet update (`//`)
// Not standard, but part of rnix AST
PipeL,
PipeR,
}
impl From<ast::BinOpKind> for BinOpKind {
fn from(op: ast::BinOpKind) -> Self {
use BinOpKind::*;
use ast::BinOpKind as kind;
match op {
kind::Concat => Con,
kind::Update => Upd,
kind::Add => Add,
kind::Sub => Sub,
kind::Mul => Mul,
kind::Div => Div,
kind::And => And,
kind::Equal => Eq,
kind::Implication => Impl,
kind::Less => Lt,
kind::LessOrEq => Leq,
kind::More => Gt,
kind::MoreOrEq => Geq,
kind::NotEqual => Neq,
kind::Or => Or,
kind::PipeLeft => PipeL,
kind::PipeRight => PipeR,
}
}
}
/// The kinds of unary operations.
#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
pub enum UnOpKind {
Neg, // Negation (`-`)
Not, // Logical not (`!`)
}
impl From<ast::UnaryOpKind> for UnOpKind {
fn from(value: ast::UnaryOpKind) -> Self {
match value {
ast::UnaryOpKind::Invert => UnOpKind::Not,
ast::UnaryOpKind::Negate => UnOpKind::Neg,
}
}
}
/// Describes the parameters of a function.
#[derive(Debug)]
pub struct Param<'ir> {
pub required: Vec<'ir, (StringId, TextRange)>,
pub optional: Vec<'ir, (StringId, TextRange)>,
pub ellipsis: bool,
}
pub fn new_global_env(
strings: &mut DefaultStringInterner,
) -> hashbrown::HashMap<StringId, Ir<'static, RawRef<'static>>> {
let mut global_env = hashbrown::HashMap::new();
let builtins_sym = StringId(strings.get_or_intern("builtins"));
global_env.insert(builtins_sym, Ir::Builtins);
for (idx, &(name, _)) in BUILTINS.iter().enumerate() {
let id = BuiltinId::try_from_primitive(idx as u8).expect("infallible");
let name = StringId(strings.get_or_intern(name));
global_env.insert(name, Ir::Builtin(id));
}
let consts = [
(
"__currentSystem",
Ir::BuiltinConst(StringId(strings.get_or_intern("currentSystem"))),
),
("__langVersion", Ir::Int(6)),
(
"__nixVersion",
Ir::BuiltinConst(StringId(strings.get_or_intern("nixVersion"))),
),
(
"__storeDir",
Ir::BuiltinConst(StringId(strings.get_or_intern("storeDir"))),
),
(
"__nixPath",
Ir::BuiltinConst(StringId(strings.get_or_intern("nixPath"))),
),
("null", Ir::Null),
("true", Ir::Bool(true)),
("false", Ir::Bool(false)),
];
for (name, ir) in consts {
let name = StringId(strings.get_or_intern(name));
global_env.insert(name, ir);
}
global_env
}