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Auto merge of #51159 - pacman82:master, r=oli-obk
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First step towards `u128` instead of `Const` in `PatternKind::Range`

This PR accomplishes two things:
* It adds `ty::Ty` to `PatternKind::Range`. The extra type information will make it easier to remove it from the `hi` and `lo` members.
* It exchanges `Const` for `u128` in `Constructor::ConstantRange`.
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@bors
bors committed Sep 12, 2018
2 parents 5806389 + 26c05b1 commit a2b991b
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Showing 3 changed files with 86 additions and 59 deletions.
5 changes: 3 additions & 2 deletions src/librustc_mir/build/matches/test.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -70,13 +70,14 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
}
}

PatternKind::Range { lo, hi, end } => {
PatternKind::Range { lo, hi, ty, end } => {
assert!(ty == match_pair.pattern.ty);
Test {
span: match_pair.pattern.span,
kind: TestKind::Range {
lo,
hi,
ty: match_pair.pattern.ty.clone(),
ty,
end,
},
}
Expand Down
131 changes: 77 additions & 54 deletions src/librustc_mir/hair/pattern/_match.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -416,7 +416,7 @@ pub enum Constructor<'tcx> {
/// Literal values.
ConstantValue(&'tcx ty::Const<'tcx>),
/// Ranges of literal values (`2...5` and `2..5`).
ConstantRange(&'tcx ty::Const<'tcx>, &'tcx ty::Const<'tcx>, RangeEnd),
ConstantRange(u128, u128, Ty<'tcx>, RangeEnd),
/// Array patterns of length n.
Slice(u64),
}
Expand Down Expand Up @@ -588,7 +588,12 @@ impl<'tcx> Witness<'tcx> {
_ => {
match *ctor {
ConstantValue(value) => PatternKind::Constant { value },
ConstantRange(lo, hi, end) => PatternKind::Range { lo, hi, end },
ConstantRange(lo, hi, ty, end) => PatternKind::Range {
lo: ty::Const::from_bits(cx.tcx, lo, ty::ParamEnv::empty().and(ty)),
hi: ty::Const::from_bits(cx.tcx, hi, ty::ParamEnv::empty().and(ty)),
ty,
end,
},
_ => PatternKind::Wild,
}
}
Expand Down Expand Up @@ -648,34 +653,32 @@ fn all_constructors<'a, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
.collect()
}
ty::Char if exhaustive_integer_patterns => {
let endpoint = |c: char| {
let ty = ty::ParamEnv::empty().and(cx.tcx.types.char);
ty::Const::from_bits(cx.tcx, c as u128, ty)
};
vec![
// The valid Unicode Scalar Value ranges.
ConstantRange(endpoint('\u{0000}'), endpoint('\u{D7FF}'), RangeEnd::Included),
ConstantRange(endpoint('\u{E000}'), endpoint('\u{10FFFF}'), RangeEnd::Included),
ConstantRange('\u{0000}' as u128,
'\u{D7FF}' as u128,
cx.tcx.types.char,
RangeEnd::Included
),
ConstantRange('\u{E000}' as u128,
'\u{10FFFF}' as u128,
cx.tcx.types.char,
RangeEnd::Included
),
]
}
ty::Int(ity) if exhaustive_integer_patterns => {
// FIXME(49937): refactor these bit manipulations into interpret.
let bits = Integer::from_attr(cx.tcx, SignedInt(ity)).size().bits() as u128;
let min = 1u128 << (bits - 1);
let max = (1u128 << (bits - 1)) - 1;
let ty = ty::ParamEnv::empty().and(pcx.ty);
vec![ConstantRange(ty::Const::from_bits(cx.tcx, min as u128, ty),
ty::Const::from_bits(cx.tcx, max as u128, ty),
RangeEnd::Included)]
vec![ConstantRange(min, max, pcx.ty, RangeEnd::Included)]
}
ty::Uint(uty) if exhaustive_integer_patterns => {
// FIXME(49937): refactor these bit manipulations into interpret.
let bits = Integer::from_attr(cx.tcx, UnsignedInt(uty)).size().bits() as u128;
let max = !0u128 >> (128 - bits);
let ty = ty::ParamEnv::empty().and(pcx.ty);
vec![ConstantRange(ty::Const::from_bits(cx.tcx, 0, ty),
ty::Const::from_bits(cx.tcx, max, ty),
RangeEnd::Included)]
vec![ConstantRange(0, max, pcx.ty, RangeEnd::Included)]
}
_ => {
if cx.is_uninhabited(pcx.ty) {
Expand Down Expand Up @@ -811,26 +814,18 @@ impl<'tcx> IntRange<'tcx> {
ctor: &Constructor<'tcx>)
-> Option<IntRange<'tcx>> {
match ctor {
ConstantRange(lo, hi, end) => {
assert_eq!(lo.ty, hi.ty);
let ty = lo.ty;
let env_ty = ty::ParamEnv::empty().and(ty);
if let Some(lo) = lo.assert_bits(tcx, env_ty) {
if let Some(hi) = hi.assert_bits(tcx, env_ty) {
// Perform a shift if the underlying types are signed,
// which makes the interval arithmetic simpler.
let bias = IntRange::signed_bias(tcx, ty);
let (lo, hi) = (lo ^ bias, hi ^ bias);
// Make sure the interval is well-formed.
return if lo > hi || lo == hi && *end == RangeEnd::Excluded {
None
} else {
let offset = (*end == RangeEnd::Excluded) as u128;
Some(IntRange { range: lo..=(hi - offset), ty })
};
}
ConstantRange(lo, hi, ty, end) => {
// Perform a shift if the underlying types are signed,
// which makes the interval arithmetic simpler.
let bias = IntRange::signed_bias(tcx, ty);
let (lo, hi) = (lo ^ bias, hi ^ bias);
// Make sure the interval is well-formed.
if lo > hi || lo == hi && *end == RangeEnd::Excluded {
None
} else {
let offset = (*end == RangeEnd::Excluded) as u128;
Some(IntRange { range: lo..=(hi - offset), ty })
}
None
}
ConstantValue(val) => {
let ty = val.ty;
Expand All @@ -853,7 +848,12 @@ impl<'tcx> IntRange<'tcx> {
-> Option<IntRange<'tcx>> {
Self::from_ctor(tcx, &match pat.kind {
box PatternKind::Constant { value } => ConstantValue(value),
box PatternKind::Range { lo, hi, end } => ConstantRange(lo, hi, end),
box PatternKind::Range { lo, hi, ty, end } => ConstantRange(
lo.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
hi.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
ty,
end,
),
_ => return None,
})
}
Expand All @@ -876,14 +876,12 @@ impl<'tcx> IntRange<'tcx> {
r: RangeInclusive<u128>,
) -> Constructor<'tcx> {
let bias = IntRange::signed_bias(tcx, ty);
let ty = ty::ParamEnv::empty().and(ty);
let (lo, hi) = r.into_inner();
if lo == hi {
let ty = ty::ParamEnv::empty().and(ty);
ConstantValue(ty::Const::from_bits(tcx, lo ^ bias, ty))
} else {
ConstantRange(ty::Const::from_bits(tcx, lo ^ bias, ty),
ty::Const::from_bits(tcx, hi ^ bias, ty),
RangeEnd::Included)
ConstantRange(lo ^ bias, hi ^ bias, ty, RangeEnd::Included)
}
}

Expand Down Expand Up @@ -1228,8 +1226,8 @@ fn is_useful_specialized<'p, 'a:'p, 'tcx: 'a>(
/// Slice patterns, however, can match slices of different lengths. For instance,
/// `[a, b, ..tail]` can match a slice of length 2, 3, 4 and so on.
///
/// Returns `None` in case of a catch-all, which can't be specialized.
fn pat_constructors<'tcx>(cx: &mut MatchCheckCtxt,
/// Returns None in case of a catch-all, which can't be specialized.
fn pat_constructors<'tcx>(cx: &mut MatchCheckCtxt<'_, 'tcx>,
pat: &Pattern<'tcx>,
pcx: PatternContext)
-> Option<Vec<Constructor<'tcx>>>
Expand All @@ -1243,7 +1241,13 @@ fn pat_constructors<'tcx>(cx: &mut MatchCheckCtxt,
Some(vec![Variant(adt_def.variants[variant_index].did)])
}
PatternKind::Constant { value } => Some(vec![ConstantValue(value)]),
PatternKind::Range { lo, hi, end } => Some(vec![ConstantRange(lo, hi, end)]),
PatternKind::Range { lo, hi, ty, end } =>
Some(vec![ConstantRange(
lo.to_bits(cx.tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
hi.to_bits(cx.tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
ty,
end,
)]),
PatternKind::Array { .. } => match pcx.ty.sty {
ty::Array(_, length) => Some(vec![
Slice(length.unwrap_usize(cx.tcx))
Expand Down Expand Up @@ -1383,10 +1387,13 @@ fn slice_pat_covered_by_constructor<'tcx>(
// constructor is a range or constant with an integer type.
fn should_treat_range_exhaustively(tcx: TyCtxt<'_, 'tcx, 'tcx>, ctor: &Constructor<'tcx>) -> bool {
if tcx.features().exhaustive_integer_patterns {
if let ConstantValue(value) | ConstantRange(value, _, _) = ctor {
if let ty::Char | ty::Int(_) | ty::Uint(_) = value.ty.sty {
return true;
}
let ty = match ctor {
ConstantValue(value) => value.ty,
ConstantRange(_, _, ty, _) => ty,
_ => return false,
};
if let ty::Char | ty::Int(_) | ty::Uint(_) = ty.sty {
return true;
}
}
false
Expand Down Expand Up @@ -1537,7 +1544,7 @@ fn constructor_covered_by_range<'a, 'tcx>(
) -> Result<bool, ErrorReported> {
let (from, to, end, ty) = match pat.kind {
box PatternKind::Constant { value } => (value, value, RangeEnd::Included, value.ty),
box PatternKind::Range { lo, hi, end } => (lo, hi, end, lo.ty),
box PatternKind::Range { lo, hi, ty, end } => (lo, hi, end, ty),
_ => bug!("`constructor_covered_by_range` called with {:?}", pat),
};
trace!("constructor_covered_by_range {:#?}, {:#?}, {:#?}, {}", ctor, from, to, ty);
Expand All @@ -1559,17 +1566,33 @@ fn constructor_covered_by_range<'a, 'tcx>(
(end == RangeEnd::Included && to == Ordering::Equal);
Ok(some_or_ok!(cmp_from(value)) && end)
},
ConstantRange(from, to, RangeEnd::Included) => {
let to = some_or_ok!(cmp_to(to));
ConstantRange(from, to, ty, RangeEnd::Included) => {
let to = some_or_ok!(cmp_to(ty::Const::from_bits(
tcx,
to,
ty::ParamEnv::empty().and(ty),
)));
let end = (to == Ordering::Less) ||
(end == RangeEnd::Included && to == Ordering::Equal);
Ok(some_or_ok!(cmp_from(from)) && end)
Ok(some_or_ok!(cmp_from(ty::Const::from_bits(
tcx,
from,
ty::ParamEnv::empty().and(ty),
))) && end)
},
ConstantRange(from, to, RangeEnd::Excluded) => {
let to = some_or_ok!(cmp_to(to));
ConstantRange(from, to, ty, RangeEnd::Excluded) => {
let to = some_or_ok!(cmp_to(ty::Const::from_bits(
tcx,
to,
ty::ParamEnv::empty().and(ty)
)));
let end = (to == Ordering::Less) ||
(end == RangeEnd::Excluded && to == Ordering::Equal);
Ok(some_or_ok!(cmp_from(from)) && end)
Ok(some_or_ok!(cmp_from(ty::Const::from_bits(
tcx,
from,
ty::ParamEnv::empty().and(ty)))
) && end)
}
Single => Ok(true),
_ => bug!(),
Expand Down
9 changes: 6 additions & 3 deletions src/librustc_mir/hair/pattern/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -106,6 +106,7 @@ pub enum PatternKind<'tcx> {
Range {
lo: &'tcx ty::Const<'tcx>,
hi: &'tcx ty::Const<'tcx>,
ty: Ty<'tcx>,
end: RangeEnd,
},

Expand Down Expand Up @@ -237,7 +238,7 @@ impl<'tcx> fmt::Display for Pattern<'tcx> {
PatternKind::Constant { value } => {
fmt_const_val(f, value)
}
PatternKind::Range { lo, hi, end } => {
PatternKind::Range { lo, hi, ty: _, end } => {
fmt_const_val(f, lo)?;
match end {
RangeEnd::Included => write!(f, "..=")?,
Expand Down Expand Up @@ -366,7 +367,7 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
);
match (end, cmp) {
(RangeEnd::Excluded, Some(Ordering::Less)) =>
PatternKind::Range { lo, hi, end },
PatternKind::Range { lo, hi, ty, end },
(RangeEnd::Excluded, _) => {
span_err!(
self.tcx.sess,
Expand All @@ -380,7 +381,7 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
PatternKind::Constant { value: lo }
}
(RangeEnd::Included, Some(Ordering::Less)) => {
PatternKind::Range { lo, hi, end }
PatternKind::Range { lo, hi, ty, end }
}
(RangeEnd::Included, _) => {
let mut err = struct_span_err!(
Expand Down Expand Up @@ -1031,10 +1032,12 @@ impl<'tcx> PatternFoldable<'tcx> for PatternKind<'tcx> {
PatternKind::Range {
lo,
hi,
ty,
end,
} => PatternKind::Range {
lo: lo.fold_with(folder),
hi: hi.fold_with(folder),
ty: ty.fold_with(folder),
end,
},
PatternKind::Slice {
Expand Down

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