Rollup merge of #151529 - tgross35:lint-apfloat, r=nnethercote
lint: Use rustc_apfloat for `overflowing_literals`, add f16 and f128 Switch to parsing float literals for overflow checks using `rustc_apfloat` rather than host floats. This avoids small variations in platform support and makes it possible to start checking `f16` and `f128` as well. Using APFloat matches what we try to do elsewhere to avoid platform inconsistencies.
This commit is contained in:
Stuart Cook
GitHub
commit
af523529be
6 changed files with 77 additions and 22 deletions
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@ -4170,6 +4170,7 @@ version = "0.0.0"
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dependencies = [
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"bitflags",
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"rustc_abi",
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"rustc_apfloat",
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"rustc_ast",
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"rustc_ast_pretty",
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"rustc_attr_parsing",
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@ -7,6 +7,7 @@ edition = "2024"
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# tidy-alphabetical-start
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bitflags = "2.4.1"
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rustc_abi = { path = "../rustc_abi" }
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rustc_apfloat = "0.2.0"
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rustc_ast = { path = "../rustc_ast" }
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rustc_ast_pretty = { path = "../rustc_ast_pretty" }
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rustc_attr_parsing = { path = "../rustc_attr_parsing" }
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@ -1,10 +1,12 @@
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use hir::{ExprKind, Node};
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use rustc_abi::{Integer, Size};
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use rustc_apfloat::Float;
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use rustc_apfloat::ieee::{DoubleS, HalfS, IeeeFloat, QuadS, Semantics, SingleS};
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use rustc_hir::{HirId, attrs};
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use rustc_middle::ty::Ty;
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use rustc_middle::ty::layout::IntegerExt;
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use rustc_middle::{bug, ty};
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use rustc_span::Span;
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use rustc_span::{Span, Symbol};
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use {rustc_ast as ast, rustc_hir as hir};
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use crate::LateContext;
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@ -383,6 +385,13 @@ fn lint_uint_literal<'tcx>(
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}
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}
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/// `None` if `v` does not parse as the float type, otherwise indicates whether a literal rounds
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/// to infinity.
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fn float_is_infinite<S: Semantics>(v: Symbol) -> Option<bool> {
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let x: IeeeFloat<S> = v.as_str().parse().ok()?;
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Some(x.is_infinite())
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}
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pub(crate) fn lint_literal<'tcx>(
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cx: &LateContext<'tcx>,
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type_limits: &TypeLimits,
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@ -405,18 +414,18 @@ pub(crate) fn lint_literal<'tcx>(
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lint_uint_literal(cx, hir_id, span, lit, t)
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}
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ty::Float(t) => {
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let (is_infinite, sym) = match lit.node {
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ast::LitKind::Float(v, _) => match t {
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// FIXME(f16_f128): add this check once `is_infinite` is reliable (ABI
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// issues resolved).
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ty::FloatTy::F16 => (Ok(false), v),
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ty::FloatTy::F32 => (v.as_str().parse().map(f32::is_infinite), v),
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ty::FloatTy::F64 => (v.as_str().parse().map(f64::is_infinite), v),
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ty::FloatTy::F128 => (Ok(false), v),
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},
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_ => bug!(),
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let ast::LitKind::Float(v, _) = lit.node else {
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bug!();
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};
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if is_infinite == Ok(true) {
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let is_infinite = match t {
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ty::FloatTy::F16 => float_is_infinite::<HalfS>(v),
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ty::FloatTy::F32 => float_is_infinite::<SingleS>(v),
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ty::FloatTy::F64 => float_is_infinite::<DoubleS>(v),
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ty::FloatTy::F128 => float_is_infinite::<QuadS>(v),
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};
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if is_infinite == Some(true) {
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cx.emit_span_lint(
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OVERFLOWING_LITERALS,
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span,
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@ -426,7 +435,7 @@ pub(crate) fn lint_literal<'tcx>(
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.sess()
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.source_map()
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.span_to_snippet(lit.span)
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.unwrap_or_else(|_| sym.to_string()),
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.unwrap_or_else(|_| v.to_string()),
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},
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);
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}
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@ -13,8 +13,14 @@ macro_rules! impl_general_format {
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($($t:ident)*) => {
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$(impl GeneralFormat for $t {
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fn already_rounded_value_should_use_exponential(&self) -> bool {
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// `max_abs` rounds to infinity for `f16`. This is fine to save us from a more
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// complex macro, it just means a positive-exponent `f16` will never print as
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// scientific notation by default (reasonably, the max is 65504.0).
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#[allow(overflowing_literals)]
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let max_abs = 1e+16;
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let abs = $t::abs(*self);
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(abs != 0.0 && abs < 1e-4) || abs >= 1e+16
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(abs != 0.0 && abs < 1e-4) || abs >= max_abs
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}
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})*
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}
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@ -1,13 +1,19 @@
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//@ compile-flags: -O
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#![feature(f16)]
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#![feature(f128)]
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#![deny(overflowing_literals)]
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fn main() {
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let x2: i8 = --128; //~ ERROR literal out of range for `i8`
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//~| WARN use of a double negation
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let x = -65520.0_f16; //~ ERROR literal out of range for `f16`
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let x = 65520.0_f16; //~ ERROR literal out of range for `f16`
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let x = -3.40282357e+38_f32; //~ ERROR literal out of range for `f32`
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let x = 3.40282357e+38_f32; //~ ERROR literal out of range for `f32`
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let x = -1.7976931348623159e+308_f64; //~ ERROR literal out of range for `f64`
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let x = 1.7976931348623159e+308_f64; //~ ERROR literal out of range for `f64`
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let x = -1.1897314953572317650857593266280075e+4932_f128; //~ ERROR literal out of range for `f128`
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let x = 1.1897314953572317650857593266280075e+4932_f128; //~ ERROR literal out of range for `f128`
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}
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@ -1,5 +1,5 @@
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warning: use of a double negation
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--> $DIR/lint-type-overflow2.rs:6:18
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--> $DIR/lint-type-overflow2.rs:8:18
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LL | let x2: i8 = --128;
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| ^^^^^
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@ -13,7 +13,7 @@ LL | let x2: i8 = -(-128);
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| + +
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error: literal out of range for `i8`
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--> $DIR/lint-type-overflow2.rs:6:20
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--> $DIR/lint-type-overflow2.rs:8:20
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LL | let x2: i8 = --128;
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| ^^^
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@ -21,13 +21,29 @@ LL | let x2: i8 = --128;
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= note: the literal `128` does not fit into the type `i8` whose range is `-128..=127`
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= help: consider using the type `u8` instead
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note: the lint level is defined here
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--> $DIR/lint-type-overflow2.rs:3:9
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--> $DIR/lint-type-overflow2.rs:5:9
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LL | #![deny(overflowing_literals)]
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| ^^^^^^^^^^^^^^^^^^^^
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error: literal out of range for `f16`
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--> $DIR/lint-type-overflow2.rs:11:14
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LL | let x = -65520.0_f16;
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| ^^^^^^^^^^^
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= note: the literal `65520.0_f16` does not fit into the type `f16` and will be converted to `f16::INFINITY`
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error: literal out of range for `f16`
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--> $DIR/lint-type-overflow2.rs:12:14
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LL | let x = 65520.0_f16;
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| ^^^^^^^^^^^
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= note: the literal `65520.0_f16` does not fit into the type `f16` and will be converted to `f16::INFINITY`
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error: literal out of range for `f32`
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--> $DIR/lint-type-overflow2.rs:9:14
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--> $DIR/lint-type-overflow2.rs:13:14
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LL | let x = -3.40282357e+38_f32;
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| ^^^^^^^^^^^^^^^^^^
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@ -35,7 +51,7 @@ LL | let x = -3.40282357e+38_f32;
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= note: the literal `3.40282357e+38_f32` does not fit into the type `f32` and will be converted to `f32::INFINITY`
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error: literal out of range for `f32`
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--> $DIR/lint-type-overflow2.rs:10:14
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--> $DIR/lint-type-overflow2.rs:14:14
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LL | let x = 3.40282357e+38_f32;
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| ^^^^^^^^^^^^^^^^^^
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@ -43,7 +59,7 @@ LL | let x = 3.40282357e+38_f32;
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= note: the literal `3.40282357e+38_f32` does not fit into the type `f32` and will be converted to `f32::INFINITY`
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error: literal out of range for `f64`
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--> $DIR/lint-type-overflow2.rs:11:14
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--> $DIR/lint-type-overflow2.rs:15:14
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LL | let x = -1.7976931348623159e+308_f64;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
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@ -51,12 +67,28 @@ LL | let x = -1.7976931348623159e+308_f64;
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= note: the literal `1.7976931348623159e+308_f64` does not fit into the type `f64` and will be converted to `f64::INFINITY`
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error: literal out of range for `f64`
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--> $DIR/lint-type-overflow2.rs:12:14
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--> $DIR/lint-type-overflow2.rs:16:14
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LL | let x = 1.7976931348623159e+308_f64;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: the literal `1.7976931348623159e+308_f64` does not fit into the type `f64` and will be converted to `f64::INFINITY`
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error: aborting due to 5 previous errors; 1 warning emitted
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error: literal out of range for `f128`
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--> $DIR/lint-type-overflow2.rs:17:14
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LL | let x = -1.1897314953572317650857593266280075e+4932_f128;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: the literal `1.1897314953572317650857593266280075e+4932_f128` does not fit into the type `f128` and will be converted to `f128::INFINITY`
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error: literal out of range for `f128`
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--> $DIR/lint-type-overflow2.rs:18:14
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LL | let x = 1.1897314953572317650857593266280075e+4932_f128;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: the literal `1.1897314953572317650857593266280075e+4932_f128` does not fit into the type `f128` and will be converted to `f128::INFINITY`
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error: aborting due to 9 previous errors; 1 warning emitted
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