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Replace f16 and f128 unimplemented!/FIXMEs with real implemen…
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…tations

This removes the ICE codepaths for `f16` and `f128`. `rustc_apfloat` is
used as a dependency for the parsing of these types, since their
`FromStr` implementation will not be available in the standard library
for a while.
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tgross35 committed Jun 18, 2024
1 parent f740aab commit 0ca844f
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Showing 5 changed files with 38 additions and 10 deletions.
7 changes: 3 additions & 4 deletions clippy_lints/src/float_literal.rs
Original file line number Diff line number Diff line change
Expand Up @@ -141,18 +141,17 @@ impl<'tcx> LateLintPass<'tcx> for FloatLiteral {
#[must_use]
fn max_digits(fty: FloatTy) -> u32 {
match fty {
// FIXME(f16_f128): replace the magic numbers once `{f16,f128}::DIGITS` are available
FloatTy::F16 => 3,
FloatTy::F16 => f16::DIGITS,
FloatTy::F32 => f32::DIGITS,
FloatTy::F64 => f64::DIGITS,
FloatTy::F128 => 33,
FloatTy::F128 => f128::DIGITS,
}
}

/// Counts the digits excluding leading zeros
#[must_use]
fn count_digits(s: &str) -> usize {
// Note that s does not contain the f32/64 suffix, and underscores have been stripped
// Note that s does not contain the `f{16,32,64,128}` suffix, and underscores have been stripped
s.chars()
.filter(|c| *c != '-' && *c != '.')
.take_while(|c| *c != 'e' && *c != 'E')
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2 changes: 2 additions & 0 deletions clippy_lints/src/lib.rs
Original file line number Diff line number Diff line change
@@ -1,6 +1,8 @@
#![feature(array_windows)]
#![feature(binary_heap_into_iter_sorted)]
#![feature(box_patterns)]
#![feature(f128)]
#![feature(f16)]
#![feature(if_let_guard)]
#![feature(iter_intersperse)]
#![feature(let_chains)]
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2 changes: 2 additions & 0 deletions clippy_utils/Cargo.toml
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@ clippy_config = { path = "../clippy_config" }
arrayvec = { version = "0.7", default-features = false }
itertools = "0.12"
rustc-semver = "1.1"
# FIXME(f16_f128): remove when no longer needed for parsing
rustc_apfloat = "0.2.0"

[features]
deny-warnings = ["clippy_config/deny-warnings"]
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35 changes: 29 additions & 6 deletions clippy_utils/src/consts.rs
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,8 @@
use crate::source::{get_source_text, walk_span_to_context};
use crate::{clip, is_direct_expn_of, sext, unsext};

use rustc_apfloat::ieee::{Half, Quad};
use rustc_apfloat::Float;
use rustc_ast::ast::{self, LitFloatType, LitKind};
use rustc_data_structures::sync::Lrc;
use rustc_hir::def::{DefKind, Res};
Expand Down Expand Up @@ -33,10 +35,14 @@ pub enum Constant<'tcx> {
Char(char),
/// An integer's bit representation.
Int(u128),
/// An `f16`.
F16(f16),
/// An `f32`.
F32(f32),
/// An `f64`.
F64(f64),
/// An `f128`.
F128(f128),
/// `true` or `false`.
Bool(bool),
/// An array of constants.
Expand Down Expand Up @@ -161,12 +167,18 @@ impl<'tcx> Hash for Constant<'tcx> {
Self::Int(i) => {
i.hash(state);
},
Self::F16(f) => {
f64::from(f).to_bits().hash(state);
},
Self::F32(f) => {
f64::from(f).to_bits().hash(state);
},
Self::F64(f) => {
f.to_bits().hash(state);
},
Self::F128(f) => {
f.to_bits().hash(state);
},
Self::Bool(b) => {
b.hash(state);
},
Expand Down Expand Up @@ -268,6 +280,16 @@ impl<'tcx> Constant<'tcx> {
}
self
}

fn parse_f16(s: &str) -> Self {
let f: Half = s.parse().unwrap();
Self::F16(f16::from_bits(f.to_bits().try_into().unwrap()))
}

fn parse_f128(s: &str) -> Self {
let f: Quad = s.parse().unwrap();
Self::F128(f128::from_bits(f.to_bits()))
}
}

/// Parses a `LitKind` to a `Constant`.
Expand All @@ -279,16 +301,17 @@ pub fn lit_to_mir_constant<'tcx>(lit: &LitKind, ty: Option<Ty<'tcx>>) -> Constan
LitKind::Char(c) => Constant::Char(c),
LitKind::Int(n, _) => Constant::Int(n.get()),
LitKind::Float(ref is, LitFloatType::Suffixed(fty)) => match fty {
ast::FloatTy::F16 => unimplemented!("f16_f128"),
// FIXME(f16_f128): just use `parse()` directly when available for `f16`/`f128`
ast::FloatTy::F16 => Constant::parse_f16(is.as_str()),
ast::FloatTy::F32 => Constant::F32(is.as_str().parse().unwrap()),
ast::FloatTy::F64 => Constant::F64(is.as_str().parse().unwrap()),
ast::FloatTy::F128 => unimplemented!("f16_f128"),
ast::FloatTy::F128 => Constant::parse_f128(is.as_str()),
},
LitKind::Float(ref is, LitFloatType::Unsuffixed) => match ty.expect("type of float is known").kind() {
ty::Float(FloatTy::F16) => unimplemented!("f16_f128"),
ty::Float(FloatTy::F16) => Constant::parse_f16(is.as_str()),
ty::Float(FloatTy::F32) => Constant::F32(is.as_str().parse().unwrap()),
ty::Float(FloatTy::F64) => Constant::F64(is.as_str().parse().unwrap()),
ty::Float(FloatTy::F128) => unimplemented!("f16_f128"),
ty::Float(FloatTy::F128) => Constant::parse_f128(is.as_str()),
_ => bug!(),
},
LitKind::Bool(b) => Constant::Bool(b),
Expand Down Expand Up @@ -835,10 +858,10 @@ pub fn mir_to_const<'tcx>(lcx: &LateContext<'tcx>, result: mir::Const<'tcx>) ->
let range = alloc_range(offset + size * idx, size);
let val = alloc.read_scalar(&lcx.tcx, range, /* read_provenance */ false).ok()?;
res.push(match flt {
FloatTy::F16 => unimplemented!("f16_f128"),
FloatTy::F16 => Constant::F16(f16::from_bits(val.to_u16().ok()?)),
FloatTy::F32 => Constant::F32(f32::from_bits(val.to_u32().ok()?)),
FloatTy::F64 => Constant::F64(f64::from_bits(val.to_u64().ok()?)),
FloatTy::F128 => unimplemented!("f16_f128"),
FloatTy::F128 => Constant::F128(f128::from_bits(val.to_u128().ok()?)),
});
}
Some(Constant::Vec(res))
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2 changes: 2 additions & 0 deletions clippy_utils/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,8 @@
#![feature(box_patterns)]
#![feature(control_flow_enum)]
#![feature(exhaustive_patterns)]
#![feature(f128)]
#![feature(f16)]
#![feature(if_let_guard)]
#![feature(let_chains)]
#![feature(lint_reasons)]
Expand Down

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