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Dedup some type checks in the MIR validator
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@scottmcm
scottmcm committed Jun 19, 2023
1 parent 3fd8501 commit c780e55
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Showing 3 changed files with 57 additions and 76 deletions.
30 changes: 4 additions & 26 deletions compiler/rustc_const_eval/src/interpret/step.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,29 +9,7 @@ use rustc_middle::mir::interpret::{InterpResult, Scalar};
use rustc_middle::ty::layout::LayoutOf;

use super::{ImmTy, InterpCx, Machine};

/// Classify whether an operator is "left-homogeneous", i.e., the LHS has the
/// same type as the result.
#[inline]
fn binop_left_homogeneous(op: mir::BinOp) -> bool {
use rustc_middle::mir::BinOp::*;
match op {
Add | AddUnchecked | Sub | SubUnchecked | Mul | MulUnchecked | Div | Rem | BitXor
| BitAnd | BitOr | Offset | Shl | ShlUnchecked | Shr | ShrUnchecked => true,
Eq | Ne | Lt | Le | Gt | Ge => false,
}
}
/// Classify whether an operator is "right-homogeneous", i.e., the RHS has the
/// same type as the LHS.
#[inline]
fn binop_right_homogeneous(op: mir::BinOp) -> bool {
use rustc_middle::mir::BinOp::*;
match op {
Add | AddUnchecked | Sub | SubUnchecked | Mul | MulUnchecked | Div | Rem | BitXor
| BitAnd | BitOr | Eq | Ne | Lt | Le | Gt | Ge => true,
Offset | Shl | ShlUnchecked | Shr | ShrUnchecked => false,
}
}
use crate::util;

impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
/// Returns `true` as long as there are more things to do.
Expand Down Expand Up @@ -181,17 +159,17 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}

BinaryOp(bin_op, box (ref left, ref right)) => {
let layout = binop_left_homogeneous(bin_op).then_some(dest.layout);
let layout = util::binop_left_homogeneous(bin_op).then_some(dest.layout);
let left = self.read_immediate(&self.eval_operand(left, layout)?)?;
let layout = binop_right_homogeneous(bin_op).then_some(left.layout);
let layout = util::binop_right_homogeneous(bin_op).then_some(left.layout);
let right = self.read_immediate(&self.eval_operand(right, layout)?)?;
self.binop_ignore_overflow(bin_op, &left, &right, &dest)?;
}

CheckedBinaryOp(bin_op, box (ref left, ref right)) => {
// Due to the extra boolean in the result, we can never reuse the `dest.layout`.
let left = self.read_immediate(&self.eval_operand(left, None)?)?;
let layout = binop_right_homogeneous(bin_op).then_some(left.layout);
let layout = util::binop_right_homogeneous(bin_op).then_some(left.layout);
let right = self.read_immediate(&self.eval_operand(right, layout)?)?;
self.binop_with_overflow(bin_op, &left, &right, &dest)?;
}
Expand Down
77 changes: 27 additions & 50 deletions compiler/rustc_const_eval/src/transform/validate.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -498,8 +498,8 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {

fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
macro_rules! check_kinds {
($t:expr, $text:literal, $($patterns:tt)*) => {
if !matches!(($t).kind(), $($patterns)*) {
($t:expr, $text:literal, $typat:pat) => {
if !matches!(($t).kind(), $typat) {
self.fail(location, format!($text, $t));
}
};
Expand Down Expand Up @@ -527,6 +527,25 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
use BinOp::*;
let a = vals.0.ty(&self.body.local_decls, self.tcx);
let b = vals.1.ty(&self.body.local_decls, self.tcx);
if crate::util::binop_right_homogeneous(*op) {
if let Eq | Lt | Le | Ne | Ge | Gt = op {
// The function pointer types can have lifetimes
if !self.mir_assign_valid_types(a, b) {
self.fail(
location,
format!("Cannot {op:?} compare incompatible types {a:?} and {b:?}"),
);
}
} else if a != b {
self.fail(
location,
format!(
"Cannot perform binary op {op:?} on unequal types {a:?} and {b:?}"
),
);
}
}

match op {
Offset => {
check_kinds!(a, "Cannot offset non-pointer type {:?}", ty::RawPtr(..));
Expand All @@ -538,7 +557,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
for x in [a, b] {
check_kinds!(
x,
"Cannot compare type {:?}",
"Cannot {op:?} compare type {:?}",
ty::Bool
| ty::Char
| ty::Int(..)
Expand All @@ -548,19 +567,13 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
| ty::FnPtr(..)
)
}
// The function pointer types can have lifetimes
if !self.mir_assign_valid_types(a, b) {
self.fail(
location,
format!("Cannot compare unequal types {:?} and {:?}", a, b),
);
}
}
Shl | ShlUnchecked | Shr | ShrUnchecked => {
AddUnchecked | SubUnchecked | MulUnchecked | Shl | ShlUnchecked | Shr
| ShrUnchecked => {
for x in [a, b] {
check_kinds!(
x,
"Cannot shift non-integer type {:?}",
"Cannot {op:?} non-integer type {:?}",
ty::Uint(..) | ty::Int(..)
)
}
Expand All @@ -569,55 +582,19 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
for x in [a, b] {
check_kinds!(
x,
"Cannot perform bitwise op on type {:?}",
"Cannot perform bitwise op {op:?} on type {:?}",
ty::Uint(..) | ty::Int(..) | ty::Bool
)
}
if a != b {
self.fail(
location,
format!(
"Cannot perform bitwise op on unequal types {:?} and {:?}",
a, b
),
);
}
}
Add | Sub | Mul | Div | Rem => {
for x in [a, b] {
check_kinds!(
x,
"Cannot perform arithmetic on type {:?}",
"Cannot perform arithmetic {op:?} on type {:?}",
ty::Uint(..) | ty::Int(..) | ty::Float(..)
)
}
if a != b {
self.fail(
location,
format!(
"Cannot perform arithmetic on unequal types {:?} and {:?}",
a, b
),
);
}
}
AddUnchecked | SubUnchecked | MulUnchecked => {
for x in [a, b] {
check_kinds!(
x,
"Cannot perform unchecked arithmetic on type {:?}",
ty::Uint(..) | ty::Int(..)
)
}
if a != b {
self.fail(
location,
format!(
"Cannot perform unchecked arithmetic on unequal types {:?} and {:?}",
a, b
),
);
}
}
}
}
Expand Down
26 changes: 26 additions & 0 deletions compiler/rustc_const_eval/src/util/mod.rs
View file
Original file line number Diff line number Diff line change
@@ -1,3 +1,5 @@
use rustc_middle::mir;

mod alignment;
mod check_validity_requirement;
mod compare_types;
Expand All @@ -7,3 +9,27 @@ pub use self::alignment::is_disaligned;
pub use self::check_validity_requirement::check_validity_requirement;
pub use self::compare_types::{is_equal_up_to_subtyping, is_subtype};
pub use self::type_name::type_name;

/// Classify whether an operator is "left-homogeneous", i.e., the LHS has the
/// same type as the result.
#[inline]
pub(crate) fn binop_left_homogeneous(op: mir::BinOp) -> bool {
use rustc_middle::mir::BinOp::*;
match op {
Add | AddUnchecked | Sub | SubUnchecked | Mul | MulUnchecked | Div | Rem | BitXor
| BitAnd | BitOr | Offset | Shl | ShlUnchecked | Shr | ShrUnchecked => true,
Eq | Ne | Lt | Le | Gt | Ge => false,
}
}

/// Classify whether an operator is "right-homogeneous", i.e., the RHS has the
/// same type as the LHS.
#[inline]
pub(crate) fn binop_right_homogeneous(op: mir::BinOp) -> bool {
use rustc_middle::mir::BinOp::*;
match op {
Add | AddUnchecked | Sub | SubUnchecked | Mul | MulUnchecked | Div | Rem | BitXor
| BitAnd | BitOr | Eq | Ne | Lt | Le | Gt | Ge => true,
Offset | Shl | ShlUnchecked | Shr | ShrUnchecked => false,
}
}

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