fe37cc1d97
Renamings: - find -> opt_hir_node - get -> hir_node - find_by_def_id -> opt_hir_node_by_def_id - get_by_def_id -> hir_node_by_def_id Fix rebase changes using removed methods Use `tcx.hir_node_by_def_id()` whenever possible in compiler Fix clippy errors Fix compiler Apply suggestions from code review Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com> Add FIXME for `tcx.hir()` returned type about its removal Simplify with with `tcx.hir_node_by_def_id`
809 lines
33 KiB
Rust
809 lines
33 KiB
Rust
#![allow(clippy::float_cmp)]
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use crate::source::{get_source_text, walk_span_to_context};
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use crate::{clip, is_direct_expn_of, sext, unsext};
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use rustc_ast::ast::{self, LitFloatType, LitKind};
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use rustc_data_structures::sync::Lrc;
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use rustc_hir::def::{DefKind, Res};
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use rustc_hir::{BinOp, BinOpKind, Block, ConstBlock, Expr, ExprKind, HirId, Item, ItemKind, Node, QPath, UnOp};
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use rustc_lexer::tokenize;
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use rustc_lint::LateContext;
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use rustc_middle::mir::interpret::{alloc_range, Scalar};
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use rustc_middle::ty::{self, EarlyBinder, FloatTy, GenericArgsRef, IntTy, List, ScalarInt, Ty, TyCtxt, UintTy};
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use rustc_middle::{bug, mir, span_bug};
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use rustc_span::symbol::{Ident, Symbol};
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use rustc_span::SyntaxContext;
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use rustc_target::abi::Size;
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use std::cmp::Ordering::{self, Equal};
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use std::hash::{Hash, Hasher};
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use std::iter;
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/// A `LitKind`-like enum to fold constant `Expr`s into.
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#[derive(Debug, Clone)]
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pub enum Constant<'tcx> {
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Adt(rustc_middle::mir::Const<'tcx>),
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/// A `String` (e.g., "abc").
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Str(String),
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/// A binary string (e.g., `b"abc"`).
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Binary(Lrc<[u8]>),
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/// A single `char` (e.g., `'a'`).
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Char(char),
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/// An integer's bit representation.
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Int(u128),
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/// An `f32`.
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F32(f32),
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/// An `f64`.
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F64(f64),
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/// `true` or `false`.
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Bool(bool),
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/// An array of constants.
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Vec(Vec<Constant<'tcx>>),
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/// Also an array, but with only one constant, repeated N times.
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Repeat(Box<Constant<'tcx>>, u64),
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/// A tuple of constants.
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Tuple(Vec<Constant<'tcx>>),
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/// A raw pointer.
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RawPtr(u128),
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/// A reference
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Ref(Box<Constant<'tcx>>),
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/// A literal with syntax error.
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Err,
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}
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trait IntTypeBounds: Sized {
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type Output: PartialOrd;
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fn min_max(self) -> Option<(Self::Output, Self::Output)>;
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fn bits(self) -> Self::Output;
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fn ensure_fits(self, val: Self::Output) -> Option<Self::Output> {
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let (min, max) = self.min_max()?;
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(min <= val && val <= max).then_some(val)
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}
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}
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impl IntTypeBounds for UintTy {
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type Output = u128;
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fn min_max(self) -> Option<(Self::Output, Self::Output)> {
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Some(match self {
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UintTy::U8 => (u8::MIN.into(), u8::MAX.into()),
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UintTy::U16 => (u16::MIN.into(), u16::MAX.into()),
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UintTy::U32 => (u32::MIN.into(), u32::MAX.into()),
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UintTy::U64 => (u64::MIN.into(), u64::MAX.into()),
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UintTy::U128 => (u128::MIN, u128::MAX),
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UintTy::Usize => (usize::MIN.try_into().ok()?, usize::MAX.try_into().ok()?),
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})
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}
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fn bits(self) -> Self::Output {
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match self {
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UintTy::U8 => 8,
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UintTy::U16 => 16,
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UintTy::U32 => 32,
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UintTy::U64 => 64,
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UintTy::U128 => 128,
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UintTy::Usize => usize::BITS.into(),
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}
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}
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}
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impl IntTypeBounds for IntTy {
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type Output = i128;
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fn min_max(self) -> Option<(Self::Output, Self::Output)> {
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Some(match self {
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IntTy::I8 => (i8::MIN.into(), i8::MAX.into()),
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IntTy::I16 => (i16::MIN.into(), i16::MAX.into()),
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IntTy::I32 => (i32::MIN.into(), i32::MAX.into()),
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IntTy::I64 => (i64::MIN.into(), i64::MAX.into()),
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IntTy::I128 => (i128::MIN, i128::MAX),
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IntTy::Isize => (isize::MIN.try_into().ok()?, isize::MAX.try_into().ok()?),
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})
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}
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fn bits(self) -> Self::Output {
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match self {
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IntTy::I8 => 8,
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IntTy::I16 => 16,
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IntTy::I32 => 32,
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IntTy::I64 => 64,
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IntTy::I128 => 128,
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IntTy::Isize => isize::BITS.into(),
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}
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}
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}
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impl<'tcx> PartialEq for Constant<'tcx> {
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fn eq(&self, other: &Self) -> bool {
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match (self, other) {
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(Self::Str(ls), Self::Str(rs)) => ls == rs,
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(Self::Binary(l), Self::Binary(r)) => l == r,
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(&Self::Char(l), &Self::Char(r)) => l == r,
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(&Self::Int(l), &Self::Int(r)) => l == r,
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(&Self::F64(l), &Self::F64(r)) => {
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// We want `Fw32 == FwAny` and `FwAny == Fw64`, and by transitivity we must have
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// `Fw32 == Fw64`, so don’t compare them.
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// `to_bits` is required to catch non-matching 0.0, -0.0, and NaNs.
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l.to_bits() == r.to_bits()
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},
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(&Self::F32(l), &Self::F32(r)) => {
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// We want `Fw32 == FwAny` and `FwAny == Fw64`, and by transitivity we must have
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// `Fw32 == Fw64`, so don’t compare them.
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// `to_bits` is required to catch non-matching 0.0, -0.0, and NaNs.
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f64::from(l).to_bits() == f64::from(r).to_bits()
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},
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(&Self::Bool(l), &Self::Bool(r)) => l == r,
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(&Self::Vec(ref l), &Self::Vec(ref r)) | (&Self::Tuple(ref l), &Self::Tuple(ref r)) => l == r,
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(Self::Repeat(lv, ls), Self::Repeat(rv, rs)) => ls == rs && lv == rv,
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(Self::Ref(lb), Self::Ref(rb)) => *lb == *rb,
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// TODO: are there inter-type equalities?
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_ => false,
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}
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}
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}
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impl<'tcx> Hash for Constant<'tcx> {
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fn hash<H>(&self, state: &mut H)
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where
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H: Hasher,
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{
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std::mem::discriminant(self).hash(state);
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match *self {
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Self::Adt(ref elem) => {
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elem.hash(state);
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},
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Self::Str(ref s) => {
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s.hash(state);
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},
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Self::Binary(ref b) => {
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b.hash(state);
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},
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Self::Char(c) => {
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c.hash(state);
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},
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Self::Int(i) => {
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i.hash(state);
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},
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Self::F32(f) => {
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f64::from(f).to_bits().hash(state);
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},
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Self::F64(f) => {
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f.to_bits().hash(state);
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},
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Self::Bool(b) => {
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b.hash(state);
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},
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Self::Vec(ref v) | Self::Tuple(ref v) => {
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v.hash(state);
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},
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Self::Repeat(ref c, l) => {
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c.hash(state);
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l.hash(state);
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},
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Self::RawPtr(u) => {
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u.hash(state);
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},
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Self::Ref(ref r) => {
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r.hash(state);
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},
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Self::Err => {},
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}
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}
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}
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impl<'tcx> Constant<'tcx> {
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pub fn partial_cmp(tcx: TyCtxt<'_>, cmp_type: Ty<'_>, left: &Self, right: &Self) -> Option<Ordering> {
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match (left, right) {
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(Self::Str(ls), Self::Str(rs)) => Some(ls.cmp(rs)),
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(Self::Char(l), Self::Char(r)) => Some(l.cmp(r)),
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(&Self::Int(l), &Self::Int(r)) => match *cmp_type.kind() {
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ty::Int(int_ty) => Some(sext(tcx, l, int_ty).cmp(&sext(tcx, r, int_ty))),
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ty::Uint(_) => Some(l.cmp(&r)),
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_ => bug!("Not an int type"),
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},
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(&Self::F64(l), &Self::F64(r)) => l.partial_cmp(&r),
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(&Self::F32(l), &Self::F32(r)) => l.partial_cmp(&r),
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(Self::Bool(l), Self::Bool(r)) => Some(l.cmp(r)),
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(Self::Tuple(l), Self::Tuple(r)) if l.len() == r.len() => match *cmp_type.kind() {
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ty::Tuple(tys) if tys.len() == l.len() => l
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.iter()
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.zip(r)
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.zip(tys)
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.map(|((li, ri), cmp_type)| Self::partial_cmp(tcx, cmp_type, li, ri))
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.find(|r| r.map_or(true, |o| o != Ordering::Equal))
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.unwrap_or_else(|| Some(l.len().cmp(&r.len()))),
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_ => None,
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},
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(Self::Vec(l), Self::Vec(r)) => {
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let (ty::Array(cmp_type, _) | ty::Slice(cmp_type)) = *cmp_type.kind() else {
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return None;
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};
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iter::zip(l, r)
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.map(|(li, ri)| Self::partial_cmp(tcx, cmp_type, li, ri))
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.find(|r| r.map_or(true, |o| o != Ordering::Equal))
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.unwrap_or_else(|| Some(l.len().cmp(&r.len())))
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},
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(Self::Repeat(lv, ls), Self::Repeat(rv, rs)) => {
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match Self::partial_cmp(
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tcx,
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match *cmp_type.kind() {
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ty::Array(ty, _) => ty,
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_ => return None,
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},
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lv,
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rv,
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) {
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Some(Equal) => Some(ls.cmp(rs)),
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x => x,
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}
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},
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(Self::Ref(lb), Self::Ref(rb)) => Self::partial_cmp(
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tcx,
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match *cmp_type.kind() {
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ty::Ref(_, ty, _) => ty,
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_ => return None,
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},
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lb,
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rb,
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),
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// TODO: are there any useful inter-type orderings?
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_ => None,
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}
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}
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/// Returns the integer value or `None` if `self` or `val_type` is not integer type.
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pub fn int_value(&self, cx: &LateContext<'_>, val_type: Ty<'_>) -> Option<FullInt> {
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if let Constant::Int(const_int) = *self {
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match *val_type.kind() {
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ty::Int(ity) => Some(FullInt::S(sext(cx.tcx, const_int, ity))),
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ty::Uint(_) => Some(FullInt::U(const_int)),
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_ => None,
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}
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} else {
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None
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}
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}
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#[must_use]
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pub fn peel_refs(mut self) -> Self {
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while let Constant::Ref(r) = self {
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self = *r;
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}
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self
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}
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}
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/// Parses a `LitKind` to a `Constant`.
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pub fn lit_to_mir_constant<'tcx>(lit: &LitKind, ty: Option<Ty<'tcx>>) -> Constant<'tcx> {
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match *lit {
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LitKind::Str(ref is, _) => Constant::Str(is.to_string()),
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LitKind::Byte(b) => Constant::Int(u128::from(b)),
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LitKind::ByteStr(ref s, _) | LitKind::CStr(ref s, _) => Constant::Binary(Lrc::clone(s)),
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LitKind::Char(c) => Constant::Char(c),
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LitKind::Int(n, _) => Constant::Int(n),
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LitKind::Float(ref is, LitFloatType::Suffixed(fty)) => match fty {
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ast::FloatTy::F32 => Constant::F32(is.as_str().parse().unwrap()),
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ast::FloatTy::F64 => Constant::F64(is.as_str().parse().unwrap()),
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},
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LitKind::Float(ref is, LitFloatType::Unsuffixed) => match ty.expect("type of float is known").kind() {
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ty::Float(FloatTy::F32) => Constant::F32(is.as_str().parse().unwrap()),
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ty::Float(FloatTy::F64) => Constant::F64(is.as_str().parse().unwrap()),
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_ => bug!(),
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},
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LitKind::Bool(b) => Constant::Bool(b),
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LitKind::Err => Constant::Err,
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}
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}
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/// The source of a constant value.
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pub enum ConstantSource {
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/// The value is determined solely from the expression.
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Local,
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/// The value is dependent on a defined constant.
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Constant,
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}
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impl ConstantSource {
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pub fn is_local(&self) -> bool {
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matches!(self, Self::Local)
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}
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}
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/// Attempts to evaluate the expression as a constant.
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pub fn constant<'tcx>(
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lcx: &LateContext<'tcx>,
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typeck_results: &ty::TypeckResults<'tcx>,
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e: &Expr<'_>,
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) -> Option<Constant<'tcx>> {
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ConstEvalLateContext::new(lcx, typeck_results).expr(e)
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}
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/// Attempts to evaluate the expression as a constant.
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pub fn constant_with_source<'tcx>(
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lcx: &LateContext<'tcx>,
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typeck_results: &ty::TypeckResults<'tcx>,
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e: &Expr<'_>,
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) -> Option<(Constant<'tcx>, ConstantSource)> {
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let mut ctxt = ConstEvalLateContext::new(lcx, typeck_results);
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let res = ctxt.expr(e);
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res.map(|x| (x, ctxt.source))
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}
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/// Attempts to evaluate an expression only if its value is not dependent on other items.
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pub fn constant_simple<'tcx>(
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lcx: &LateContext<'tcx>,
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typeck_results: &ty::TypeckResults<'tcx>,
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e: &Expr<'_>,
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) -> Option<Constant<'tcx>> {
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constant_with_source(lcx, typeck_results, e).and_then(|(c, s)| s.is_local().then_some(c))
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}
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pub fn constant_full_int<'tcx>(
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lcx: &LateContext<'tcx>,
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typeck_results: &ty::TypeckResults<'tcx>,
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e: &Expr<'_>,
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) -> Option<FullInt> {
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constant_simple(lcx, typeck_results, e)?.int_value(lcx, typeck_results.expr_ty(e))
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}
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#[derive(Copy, Clone, Debug, Eq)]
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pub enum FullInt {
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S(i128),
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U(u128),
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}
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impl PartialEq for FullInt {
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#[must_use]
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fn eq(&self, other: &Self) -> bool {
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self.cmp(other) == Ordering::Equal
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}
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}
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impl PartialOrd for FullInt {
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#[must_use]
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fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
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Some(self.cmp(other))
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}
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}
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impl Ord for FullInt {
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#[must_use]
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fn cmp(&self, other: &Self) -> Ordering {
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use FullInt::{S, U};
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fn cmp_s_u(s: i128, u: u128) -> Ordering {
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u128::try_from(s).map_or(Ordering::Less, |x| x.cmp(&u))
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}
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match (*self, *other) {
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(S(s), S(o)) => s.cmp(&o),
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(U(s), U(o)) => s.cmp(&o),
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(S(s), U(o)) => cmp_s_u(s, o),
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(U(s), S(o)) => cmp_s_u(o, s).reverse(),
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}
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}
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}
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pub struct ConstEvalLateContext<'a, 'tcx> {
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lcx: &'a LateContext<'tcx>,
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typeck_results: &'a ty::TypeckResults<'tcx>,
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param_env: ty::ParamEnv<'tcx>,
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source: ConstantSource,
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args: GenericArgsRef<'tcx>,
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}
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impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
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pub fn new(lcx: &'a LateContext<'tcx>, typeck_results: &'a ty::TypeckResults<'tcx>) -> Self {
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Self {
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lcx,
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typeck_results,
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param_env: lcx.param_env,
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source: ConstantSource::Local,
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args: List::empty(),
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}
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}
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/// Simple constant folding: Insert an expression, get a constant or none.
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pub fn expr(&mut self, e: &Expr<'_>) -> Option<Constant<'tcx>> {
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match e.kind {
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ExprKind::ConstBlock(ConstBlock { body, .. }) => self.expr(self.lcx.tcx.hir().body(body).value),
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ExprKind::DropTemps(e) => self.expr(e),
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ExprKind::Path(ref qpath) => self.fetch_path(qpath, e.hir_id, self.typeck_results.expr_ty(e)),
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ExprKind::Block(block, _) => self.block(block),
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ExprKind::Lit(lit) => {
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if is_direct_expn_of(e.span, "cfg").is_some() {
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None
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} else {
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Some(lit_to_mir_constant(&lit.node, self.typeck_results.expr_ty_opt(e)))
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}
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},
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ExprKind::Array(vec) => self.multi(vec).map(Constant::Vec),
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ExprKind::Tup(tup) => self.multi(tup).map(Constant::Tuple),
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ExprKind::Repeat(value, _) => {
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let n = match self.typeck_results.expr_ty(e).kind() {
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ty::Array(_, n) => n.try_eval_target_usize(self.lcx.tcx, self.lcx.param_env)?,
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_ => span_bug!(e.span, "typeck error"),
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};
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self.expr(value).map(|v| Constant::Repeat(Box::new(v), n))
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},
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ExprKind::Unary(op, operand) => self.expr(operand).and_then(|o| match op {
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UnOp::Not => self.constant_not(&o, self.typeck_results.expr_ty(e)),
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UnOp::Neg => self.constant_negate(&o, self.typeck_results.expr_ty(e)),
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UnOp::Deref => Some(if let Constant::Ref(r) = o { *r } else { o }),
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}),
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ExprKind::If(cond, then, ref otherwise) => self.ifthenelse(cond, then, *otherwise),
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ExprKind::Binary(op, left, right) => self.binop(op, left, right),
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ExprKind::Call(callee, args) => {
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// We only handle a few const functions for now.
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if args.is_empty()
|
||
&& let ExprKind::Path(qpath) = &callee.kind
|
||
&& let res = self.typeck_results.qpath_res(qpath, callee.hir_id)
|
||
&& let Some(def_id) = res.opt_def_id()
|
||
&& let def_path = self.lcx.get_def_path(def_id)
|
||
&& let def_path = def_path.iter().take(4).map(Symbol::as_str).collect::<Vec<_>>()
|
||
&& let ["core", "num", int_impl, "max_value"] = *def_path
|
||
{
|
||
let value = match int_impl {
|
||
"<impl i8>" => i8::MAX as u128,
|
||
"<impl i16>" => i16::MAX as u128,
|
||
"<impl i32>" => i32::MAX as u128,
|
||
"<impl i64>" => i64::MAX as u128,
|
||
"<impl i128>" => i128::MAX as u128,
|
||
_ => return None,
|
||
};
|
||
Some(Constant::Int(value))
|
||
} else {
|
||
None
|
||
}
|
||
},
|
||
ExprKind::Index(arr, index, _) => self.index(arr, index),
|
||
ExprKind::AddrOf(_, _, inner) => self.expr(inner).map(|r| Constant::Ref(Box::new(r))),
|
||
ExprKind::Field(local_expr, ref field) => {
|
||
let result = self.expr(local_expr);
|
||
if let Some(Constant::Adt(constant)) = &self.expr(local_expr)
|
||
&& let ty::Adt(adt_def, _) = constant.ty().kind()
|
||
&& adt_def.is_struct()
|
||
&& let Some(desired_field) = field_of_struct(*adt_def, self.lcx, *constant, field)
|
||
{
|
||
mir_to_const(self.lcx, desired_field)
|
||
} else {
|
||
result
|
||
}
|
||
},
|
||
_ => None,
|
||
}
|
||
}
|
||
|
||
#[expect(clippy::cast_possible_wrap)]
|
||
fn constant_not(&self, o: &Constant<'tcx>, ty: Ty<'_>) -> Option<Constant<'tcx>> {
|
||
use self::Constant::{Bool, Int};
|
||
match *o {
|
||
Bool(b) => Some(Bool(!b)),
|
||
Int(value) => {
|
||
let value = !value;
|
||
match *ty.kind() {
|
||
ty::Int(ity) => Some(Int(unsext(self.lcx.tcx, value as i128, ity))),
|
||
ty::Uint(ity) => Some(Int(clip(self.lcx.tcx, value, ity))),
|
||
_ => None,
|
||
}
|
||
},
|
||
_ => None,
|
||
}
|
||
}
|
||
|
||
fn constant_negate(&self, o: &Constant<'tcx>, ty: Ty<'_>) -> Option<Constant<'tcx>> {
|
||
use self::Constant::{Int, F32, F64};
|
||
match *o {
|
||
Int(value) => {
|
||
let ty::Int(ity) = *ty.kind() else { return None };
|
||
let (min, _) = ity.min_max()?;
|
||
// sign extend
|
||
let value = sext(self.lcx.tcx, value, ity);
|
||
|
||
// Applying unary - to the most negative value of any signed integer type panics.
|
||
if value == min {
|
||
return None;
|
||
}
|
||
|
||
let value = value.checked_neg()?;
|
||
// clear unused bits
|
||
Some(Int(unsext(self.lcx.tcx, value, ity)))
|
||
},
|
||
F32(f) => Some(F32(-f)),
|
||
F64(f) => Some(F64(-f)),
|
||
_ => None,
|
||
}
|
||
}
|
||
|
||
/// Create `Some(Vec![..])` of all constants, unless there is any
|
||
/// non-constant part.
|
||
fn multi(&mut self, vec: &[Expr<'_>]) -> Option<Vec<Constant<'tcx>>> {
|
||
vec.iter().map(|elem| self.expr(elem)).collect::<Option<_>>()
|
||
}
|
||
|
||
/// Lookup a possibly constant expression from an `ExprKind::Path`.
|
||
fn fetch_path(&mut self, qpath: &QPath<'_>, id: HirId, ty: Ty<'tcx>) -> Option<Constant<'tcx>> {
|
||
let res = self.typeck_results.qpath_res(qpath, id);
|
||
match res {
|
||
Res::Def(DefKind::Const | DefKind::AssocConst, def_id) => {
|
||
// Check if this constant is based on `cfg!(..)`,
|
||
// which is NOT constant for our purposes.
|
||
if let Some(node) = self.lcx.tcx.hir().get_if_local(def_id)
|
||
&& let Node::Item(Item {
|
||
kind: ItemKind::Const(.., body_id),
|
||
..
|
||
}) = node
|
||
&& let Node::Expr(Expr {
|
||
kind: ExprKind::Lit(_),
|
||
span,
|
||
..
|
||
}) = self.lcx.tcx.hir_node(body_id.hir_id)
|
||
&& is_direct_expn_of(*span, "cfg").is_some()
|
||
{
|
||
return None;
|
||
}
|
||
|
||
let args = self.typeck_results.node_args(id);
|
||
let args = if self.args.is_empty() {
|
||
args
|
||
} else {
|
||
EarlyBinder::bind(args).instantiate(self.lcx.tcx, self.args)
|
||
};
|
||
let result = self
|
||
.lcx
|
||
.tcx
|
||
.const_eval_resolve(self.param_env, mir::UnevaluatedConst::new(def_id, args), None)
|
||
.ok()
|
||
.map(|val| rustc_middle::mir::Const::from_value(val, ty))?;
|
||
let result = mir_to_const(self.lcx, result)?;
|
||
self.source = ConstantSource::Constant;
|
||
Some(result)
|
||
},
|
||
_ => None,
|
||
}
|
||
}
|
||
|
||
fn index(&mut self, lhs: &'_ Expr<'_>, index: &'_ Expr<'_>) -> Option<Constant<'tcx>> {
|
||
let lhs = self.expr(lhs);
|
||
let index = self.expr(index);
|
||
|
||
match (lhs, index) {
|
||
(Some(Constant::Vec(vec)), Some(Constant::Int(index))) => match vec.get(index as usize) {
|
||
Some(Constant::F32(x)) => Some(Constant::F32(*x)),
|
||
Some(Constant::F64(x)) => Some(Constant::F64(*x)),
|
||
_ => None,
|
||
},
|
||
(Some(Constant::Vec(vec)), _) => {
|
||
if !vec.is_empty() && vec.iter().all(|x| *x == vec[0]) {
|
||
match vec.first() {
|
||
Some(Constant::F32(x)) => Some(Constant::F32(*x)),
|
||
Some(Constant::F64(x)) => Some(Constant::F64(*x)),
|
||
_ => None,
|
||
}
|
||
} else {
|
||
None
|
||
}
|
||
},
|
||
_ => None,
|
||
}
|
||
}
|
||
|
||
/// A block can only yield a constant if it only has one constant expression.
|
||
fn block(&mut self, block: &Block<'_>) -> Option<Constant<'tcx>> {
|
||
if block.stmts.is_empty()
|
||
&& let Some(expr) = block.expr
|
||
{
|
||
// Try to detect any `cfg`ed statements or empty macro expansions.
|
||
let span = block.span.data();
|
||
if span.ctxt == SyntaxContext::root() {
|
||
if let Some(expr_span) = walk_span_to_context(expr.span, span.ctxt)
|
||
&& let expr_lo = expr_span.lo()
|
||
&& expr_lo >= span.lo
|
||
&& let Some(src) = get_source_text(self.lcx, span.lo..expr_lo)
|
||
&& let Some(src) = src.as_str()
|
||
{
|
||
use rustc_lexer::TokenKind::{BlockComment, LineComment, OpenBrace, Semi, Whitespace};
|
||
if !tokenize(src)
|
||
.map(|t| t.kind)
|
||
.filter(|t| !matches!(t, Whitespace | LineComment { .. } | BlockComment { .. } | Semi))
|
||
.eq([OpenBrace])
|
||
{
|
||
self.source = ConstantSource::Constant;
|
||
}
|
||
} else {
|
||
// Unable to access the source. Assume a non-local dependency.
|
||
self.source = ConstantSource::Constant;
|
||
}
|
||
}
|
||
|
||
self.expr(expr)
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
|
||
fn ifthenelse(&mut self, cond: &Expr<'_>, then: &Expr<'_>, otherwise: Option<&Expr<'_>>) -> Option<Constant<'tcx>> {
|
||
if let Some(Constant::Bool(b)) = self.expr(cond) {
|
||
if b {
|
||
self.expr(then)
|
||
} else {
|
||
otherwise.as_ref().and_then(|expr| self.expr(expr))
|
||
}
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
|
||
fn binop(&mut self, op: BinOp, left: &Expr<'_>, right: &Expr<'_>) -> Option<Constant<'tcx>> {
|
||
let l = self.expr(left)?;
|
||
let r = self.expr(right);
|
||
match (l, r) {
|
||
(Constant::Int(l), Some(Constant::Int(r))) => match *self.typeck_results.expr_ty_opt(left)?.kind() {
|
||
ty::Int(ity) => {
|
||
let (ty_min_value, _) = ity.min_max()?;
|
||
let bits = ity.bits();
|
||
let l = sext(self.lcx.tcx, l, ity);
|
||
let r = sext(self.lcx.tcx, r, ity);
|
||
|
||
// Using / or %, where the left-hand argument is the smallest integer of a signed integer type and
|
||
// the right-hand argument is -1 always panics, even with overflow-checks disabled
|
||
if let BinOpKind::Div | BinOpKind::Rem = op.node
|
||
&& l == ty_min_value
|
||
&& r == -1
|
||
{
|
||
return None;
|
||
}
|
||
|
||
let zext = |n: i128| Constant::Int(unsext(self.lcx.tcx, n, ity));
|
||
match op.node {
|
||
// When +, * or binary - create a value greater than the maximum value, or less than
|
||
// the minimum value that can be stored, it panics.
|
||
BinOpKind::Add => l.checked_add(r).and_then(|n| ity.ensure_fits(n)).map(zext),
|
||
BinOpKind::Sub => l.checked_sub(r).and_then(|n| ity.ensure_fits(n)).map(zext),
|
||
BinOpKind::Mul => l.checked_mul(r).and_then(|n| ity.ensure_fits(n)).map(zext),
|
||
BinOpKind::Div if r != 0 => l.checked_div(r).map(zext),
|
||
BinOpKind::Rem if r != 0 => l.checked_rem(r).map(zext),
|
||
// Using << or >> where the right-hand argument is greater than or equal to the number of bits
|
||
// in the type of the left-hand argument, or is negative panics.
|
||
BinOpKind::Shr if r < bits && !r.is_negative() => l.checked_shr(r.try_into().ok()?).map(zext),
|
||
BinOpKind::Shl if r < bits && !r.is_negative() => l.checked_shl(r.try_into().ok()?).map(zext),
|
||
BinOpKind::BitXor => Some(zext(l ^ r)),
|
||
BinOpKind::BitOr => Some(zext(l | r)),
|
||
BinOpKind::BitAnd => Some(zext(l & r)),
|
||
BinOpKind::Eq => Some(Constant::Bool(l == r)),
|
||
BinOpKind::Ne => Some(Constant::Bool(l != r)),
|
||
BinOpKind::Lt => Some(Constant::Bool(l < r)),
|
||
BinOpKind::Le => Some(Constant::Bool(l <= r)),
|
||
BinOpKind::Ge => Some(Constant::Bool(l >= r)),
|
||
BinOpKind::Gt => Some(Constant::Bool(l > r)),
|
||
_ => None,
|
||
}
|
||
},
|
||
ty::Uint(ity) => {
|
||
let bits = ity.bits();
|
||
|
||
match op.node {
|
||
BinOpKind::Add => l.checked_add(r).and_then(|n| ity.ensure_fits(n)).map(Constant::Int),
|
||
BinOpKind::Sub => l.checked_sub(r).and_then(|n| ity.ensure_fits(n)).map(Constant::Int),
|
||
BinOpKind::Mul => l.checked_mul(r).and_then(|n| ity.ensure_fits(n)).map(Constant::Int),
|
||
BinOpKind::Div => l.checked_div(r).map(Constant::Int),
|
||
BinOpKind::Rem => l.checked_rem(r).map(Constant::Int),
|
||
BinOpKind::Shr if r < bits => l.checked_shr(r.try_into().ok()?).map(Constant::Int),
|
||
BinOpKind::Shl if r < bits => l.checked_shl(r.try_into().ok()?).map(Constant::Int),
|
||
BinOpKind::BitXor => Some(Constant::Int(l ^ r)),
|
||
BinOpKind::BitOr => Some(Constant::Int(l | r)),
|
||
BinOpKind::BitAnd => Some(Constant::Int(l & r)),
|
||
BinOpKind::Eq => Some(Constant::Bool(l == r)),
|
||
BinOpKind::Ne => Some(Constant::Bool(l != r)),
|
||
BinOpKind::Lt => Some(Constant::Bool(l < r)),
|
||
BinOpKind::Le => Some(Constant::Bool(l <= r)),
|
||
BinOpKind::Ge => Some(Constant::Bool(l >= r)),
|
||
BinOpKind::Gt => Some(Constant::Bool(l > r)),
|
||
_ => None,
|
||
}
|
||
},
|
||
_ => None,
|
||
},
|
||
(Constant::F32(l), Some(Constant::F32(r))) => match op.node {
|
||
BinOpKind::Add => Some(Constant::F32(l + r)),
|
||
BinOpKind::Sub => Some(Constant::F32(l - r)),
|
||
BinOpKind::Mul => Some(Constant::F32(l * r)),
|
||
BinOpKind::Div => Some(Constant::F32(l / r)),
|
||
BinOpKind::Rem => Some(Constant::F32(l % r)),
|
||
BinOpKind::Eq => Some(Constant::Bool(l == r)),
|
||
BinOpKind::Ne => Some(Constant::Bool(l != r)),
|
||
BinOpKind::Lt => Some(Constant::Bool(l < r)),
|
||
BinOpKind::Le => Some(Constant::Bool(l <= r)),
|
||
BinOpKind::Ge => Some(Constant::Bool(l >= r)),
|
||
BinOpKind::Gt => Some(Constant::Bool(l > r)),
|
||
_ => None,
|
||
},
|
||
(Constant::F64(l), Some(Constant::F64(r))) => match op.node {
|
||
BinOpKind::Add => Some(Constant::F64(l + r)),
|
||
BinOpKind::Sub => Some(Constant::F64(l - r)),
|
||
BinOpKind::Mul => Some(Constant::F64(l * r)),
|
||
BinOpKind::Div => Some(Constant::F64(l / r)),
|
||
BinOpKind::Rem => Some(Constant::F64(l % r)),
|
||
BinOpKind::Eq => Some(Constant::Bool(l == r)),
|
||
BinOpKind::Ne => Some(Constant::Bool(l != r)),
|
||
BinOpKind::Lt => Some(Constant::Bool(l < r)),
|
||
BinOpKind::Le => Some(Constant::Bool(l <= r)),
|
||
BinOpKind::Ge => Some(Constant::Bool(l >= r)),
|
||
BinOpKind::Gt => Some(Constant::Bool(l > r)),
|
||
_ => None,
|
||
},
|
||
(l, r) => match (op.node, l, r) {
|
||
(BinOpKind::And, Constant::Bool(false), _) => Some(Constant::Bool(false)),
|
||
(BinOpKind::Or, Constant::Bool(true), _) => Some(Constant::Bool(true)),
|
||
(BinOpKind::And, Constant::Bool(true), Some(r)) | (BinOpKind::Or, Constant::Bool(false), Some(r)) => {
|
||
Some(r)
|
||
},
|
||
(BinOpKind::BitXor, Constant::Bool(l), Some(Constant::Bool(r))) => Some(Constant::Bool(l ^ r)),
|
||
(BinOpKind::BitAnd, Constant::Bool(l), Some(Constant::Bool(r))) => Some(Constant::Bool(l & r)),
|
||
(BinOpKind::BitOr, Constant::Bool(l), Some(Constant::Bool(r))) => Some(Constant::Bool(l | r)),
|
||
_ => None,
|
||
},
|
||
}
|
||
}
|
||
}
|
||
|
||
pub fn mir_to_const<'tcx>(lcx: &LateContext<'tcx>, result: mir::Const<'tcx>) -> Option<Constant<'tcx>> {
|
||
use rustc_middle::mir::ConstValue;
|
||
let mir::Const::Val(val, _) = result else {
|
||
// We only work on evaluated consts.
|
||
return None;
|
||
};
|
||
match (val, result.ty().kind()) {
|
||
(ConstValue::Scalar(Scalar::Int(int)), _) => match result.ty().kind() {
|
||
ty::Adt(adt_def, _) if adt_def.is_struct() => Some(Constant::Adt(result)),
|
||
ty::Bool => Some(Constant::Bool(int == ScalarInt::TRUE)),
|
||
ty::Uint(_) | ty::Int(_) => Some(Constant::Int(int.assert_bits(int.size()))),
|
||
ty::Float(FloatTy::F32) => Some(Constant::F32(f32::from_bits(
|
||
int.try_into().expect("invalid f32 bit representation"),
|
||
))),
|
||
ty::Float(FloatTy::F64) => Some(Constant::F64(f64::from_bits(
|
||
int.try_into().expect("invalid f64 bit representation"),
|
||
))),
|
||
ty::RawPtr(_) => Some(Constant::RawPtr(int.assert_bits(int.size()))),
|
||
_ => None,
|
||
},
|
||
(_, ty::Ref(_, inner_ty, _)) if matches!(inner_ty.kind(), ty::Str) => {
|
||
let data = val.try_get_slice_bytes_for_diagnostics(lcx.tcx)?;
|
||
String::from_utf8(data.to_owned()).ok().map(Constant::Str)
|
||
},
|
||
(_, ty::Adt(adt_def, _)) if adt_def.is_struct() => Some(Constant::Adt(result)),
|
||
(ConstValue::Indirect { alloc_id, offset }, ty::Array(sub_type, len)) => {
|
||
let alloc = lcx.tcx.global_alloc(alloc_id).unwrap_memory().inner();
|
||
let len = len.try_to_target_usize(lcx.tcx)?;
|
||
let ty::Float(flt) = sub_type.kind() else {
|
||
return None;
|
||
};
|
||
let size = Size::from_bits(flt.bit_width());
|
||
let mut res = Vec::new();
|
||
for idx in 0..len {
|
||
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::F32 => Constant::F32(f32::from_bits(val.to_u32().ok()?)),
|
||
FloatTy::F64 => Constant::F64(f64::from_bits(val.to_u64().ok()?)),
|
||
});
|
||
}
|
||
Some(Constant::Vec(res))
|
||
},
|
||
_ => None,
|
||
}
|
||
}
|
||
|
||
fn field_of_struct<'tcx>(
|
||
adt_def: ty::AdtDef<'tcx>,
|
||
lcx: &LateContext<'tcx>,
|
||
result: mir::Const<'tcx>,
|
||
field: &Ident,
|
||
) -> Option<mir::Const<'tcx>> {
|
||
if let mir::Const::Val(result, ty) = result
|
||
&& let Some(dc) = lcx.tcx.try_destructure_mir_constant_for_user_output(result, ty)
|
||
&& let Some(dc_variant) = dc.variant
|
||
&& let Some(variant) = adt_def.variants().get(dc_variant)
|
||
&& let Some(field_idx) = variant.fields.iter().position(|el| el.name == field.name)
|
||
&& let Some(&(val, ty)) = dc.fields.get(field_idx)
|
||
{
|
||
Some(mir::Const::Val(val, ty))
|
||
} else {
|
||
None
|
||
}
|
||
}
|