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Diffstat (limited to 'crates/hir-ty/src/consteval_chalk.rs')
| -rw-r--r-- | crates/hir-ty/src/consteval_chalk.rs | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/crates/hir-ty/src/consteval_chalk.rs b/crates/hir-ty/src/consteval_chalk.rs new file mode 100644 index 0000000000..458974384d --- /dev/null +++ b/crates/hir-ty/src/consteval_chalk.rs @@ -0,0 +1,185 @@ +//! Constant evaluation details + +use base_db::Crate; +use chalk_ir::{BoundVar, DebruijnIndex, cast::Cast}; +use hir_def::{ + expr_store::{HygieneId, path::Path}, + resolver::{Resolver, ValueNs}, + type_ref::LiteralConstRef, +}; +use stdx::never; + +use crate::{ + Const, ConstData, ConstScalar, ConstValue, GenericArg, Interner, MemoryMap, Substitution, + TraitEnvironment, Ty, TyBuilder, + db::HirDatabase, + generics::Generics, + lower::ParamLoweringMode, + next_solver::{ + DbInterner, + mapping::{ChalkToNextSolver, NextSolverToChalk}, + }, + to_placeholder_idx, +}; + +use super::mir::pad16; + +/// Extension trait for [`Const`] +pub trait ConstExt { + /// Is a [`Const`] unknown? + fn is_unknown(&self) -> bool; +} + +impl ConstExt for Const { + fn is_unknown(&self) -> bool { + match self.data(Interner).value { + // interned Unknown + chalk_ir::ConstValue::Concrete(chalk_ir::ConcreteConst { + interned: ConstScalar::Unknown, + }) => true, + + // interned concrete anything else + chalk_ir::ConstValue::Concrete(..) => false, + + _ => { + tracing::error!( + "is_unknown was called on a non-concrete constant value! {:?}", + self + ); + true + } + } + } +} + +pub fn path_to_const<'g>( + db: &dyn HirDatabase, + resolver: &Resolver<'_>, + path: &Path, + mode: ParamLoweringMode, + args: impl FnOnce() -> &'g Generics, + debruijn: DebruijnIndex, + expected_ty: Ty, +) -> Option<Const> { + match resolver.resolve_path_in_value_ns_fully(db, path, HygieneId::ROOT) { + Some(ValueNs::GenericParam(p)) => { + let ty = db.const_param_ty(p); + let args = args(); + let value = match mode { + ParamLoweringMode::Placeholder => { + let idx = args.type_or_const_param_idx(p.into()).unwrap(); + ConstValue::Placeholder(to_placeholder_idx(db, p.into(), idx as u32)) + } + ParamLoweringMode::Variable => match args.type_or_const_param_idx(p.into()) { + Some(it) => ConstValue::BoundVar(BoundVar::new(debruijn, it)), + None => { + never!( + "Generic list doesn't contain this param: {:?}, {:?}, {:?}", + args, + path, + p + ); + return None; + } + }, + }; + Some(ConstData { ty, value }.intern(Interner)) + } + Some(ValueNs::ConstId(c)) => Some(intern_const_scalar( + ConstScalar::UnevaluatedConst(c.into(), Substitution::empty(Interner)), + expected_ty, + )), + // FIXME: With feature(adt_const_params), we also need to consider other things here, e.g. struct constructors. + _ => None, + } +} + +pub fn unknown_const(ty: Ty) -> Const { + ConstData { + ty, + value: ConstValue::Concrete(chalk_ir::ConcreteConst { interned: ConstScalar::Unknown }), + } + .intern(Interner) +} + +pub fn unknown_const_as_generic(ty: Ty) -> GenericArg { + unknown_const(ty).cast(Interner) +} + +/// Interns a constant scalar with the given type +pub fn intern_const_scalar(value: ConstScalar, ty: Ty) -> Const { + ConstData { ty, value: ConstValue::Concrete(chalk_ir::ConcreteConst { interned: value }) } + .intern(Interner) +} + +/// Interns a constant scalar with the given type +pub fn intern_const_ref( + db: &dyn HirDatabase, + value: &LiteralConstRef, + ty: Ty, + krate: Crate, +) -> Const { + let interner = DbInterner::new_with(db, Some(krate), None); + let layout = || db.layout_of_ty(ty.to_nextsolver(interner), TraitEnvironment::empty(krate)); + let bytes = match value { + LiteralConstRef::Int(i) => { + // FIXME: We should handle failure of layout better. + let size = layout().map(|it| it.size.bytes_usize()).unwrap_or(16); + ConstScalar::Bytes(i.to_le_bytes()[0..size].into(), MemoryMap::default()) + } + LiteralConstRef::UInt(i) => { + let size = layout().map(|it| it.size.bytes_usize()).unwrap_or(16); + ConstScalar::Bytes(i.to_le_bytes()[0..size].into(), MemoryMap::default()) + } + LiteralConstRef::Bool(b) => ConstScalar::Bytes(Box::new([*b as u8]), MemoryMap::default()), + LiteralConstRef::Char(c) => { + ConstScalar::Bytes((*c as u32).to_le_bytes().into(), MemoryMap::default()) + } + LiteralConstRef::Unknown => ConstScalar::Unknown, + }; + intern_const_scalar(bytes, ty) +} + +/// Interns a possibly-unknown target usize +pub fn usize_const(db: &dyn HirDatabase, value: Option<u128>, krate: Crate) -> Const { + intern_const_ref( + db, + &value.map_or(LiteralConstRef::Unknown, LiteralConstRef::UInt), + TyBuilder::usize(), + krate, + ) +} + +pub fn try_const_usize(db: &dyn HirDatabase, c: &Const) -> Option<u128> { + let interner = DbInterner::new_with(db, None, None); + match &c.data(Interner).value { + chalk_ir::ConstValue::BoundVar(_) => None, + chalk_ir::ConstValue::InferenceVar(_) => None, + chalk_ir::ConstValue::Placeholder(_) => None, + chalk_ir::ConstValue::Concrete(c) => match &c.interned { + ConstScalar::Bytes(it, _) => Some(u128::from_le_bytes(pad16(it, false))), + ConstScalar::UnevaluatedConst(c, subst) => { + let ec = db.const_eval(*c, subst.to_nextsolver(interner), None).ok()?; + try_const_usize(db, &ec.to_chalk(interner)) + } + _ => None, + }, + } +} + +pub fn try_const_isize(db: &dyn HirDatabase, c: &Const) -> Option<i128> { + let interner = DbInterner::new_with(db, None, None); + match &c.data(Interner).value { + chalk_ir::ConstValue::BoundVar(_) => None, + chalk_ir::ConstValue::InferenceVar(_) => None, + chalk_ir::ConstValue::Placeholder(_) => None, + chalk_ir::ConstValue::Concrete(c) => match &c.interned { + ConstScalar::Bytes(it, _) => Some(i128::from_le_bytes(pad16(it, true))), + ConstScalar::UnevaluatedConst(c, subst) => { + let ec = db.const_eval(*c, subst.to_nextsolver(interner), None).ok()?; + try_const_isize(db, &ec.to_chalk(interner)) + } + _ => None, + }, + } +} |