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Auto merge of #63658 - RalfJung:miri-op, r=oli-obk

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Refactor Miri ops (unary, binary) to have more types

This is the part of https://github.com/rust-lang/rust/pull/63448 that is just a refactoring. It helps that PR by making it easier to perform machine arithmetic.

r? @oli-obk @eddyb
This commit is contained in:
bors 2019-08-17 17:53:31 +00:00
commit 2111aed0a3
9 changed files with 112 additions and 92 deletions
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5
src/librustc_mir/const_eval.rs
View File

@ -11,9 +11,8 @@ use rustc::hir::def::DefKind;
use rustc::hir::def_id::DefId;
use rustc::mir::interpret::{ConstEvalErr, ErrorHandled, ScalarMaybeUndef};
use rustc::mir;
use rustc::ty::{self, TyCtxt};
use rustc::ty::{self, Ty, TyCtxt, subst::Subst};
use rustc::ty::layout::{self, LayoutOf, VariantIdx};
use rustc::ty::subst::Subst;
use rustc::traits::Reveal;
use rustc_data_structures::fx::FxHashMap;
@ -415,7 +414,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
_bin_op: mir::BinOp,
_left: ImmTy<'tcx>,
_right: ImmTy<'tcx>,
) -> InterpResult<'tcx, (Scalar, bool)> {
) -> InterpResult<'tcx, (Scalar, bool, Ty<'tcx>)> {
Err(
ConstEvalError::NeedsRfc("pointer arithmetic or comparison".to_string()).into(),
)

4
src/librustc_mir/interpret/intrinsics.rs
View File

@ -137,7 +137,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
let l = self.read_immediate(args[0])?;
let r = self.read_immediate(args[1])?;
let is_add = intrinsic_name == "saturating_add";
let (val, overflowed) = self.binary_op(if is_add {
let (val, overflowed, _ty) = self.overflowing_binary_op(if is_add {
BinOp::Add
} else {
BinOp::Sub
@ -184,7 +184,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
"unchecked_shr" => BinOp::Shr,
_ => bug!("Already checked for int ops")
};
let (val, overflowed) = self.binary_op(bin_op, l, r)?;
let (val, overflowed, _ty) = self.overflowing_binary_op(bin_op, l, r)?;
if overflowed {
let layout = self.layout_of(substs.type_at(0))?;
let r_val = r.to_scalar()?.to_bits(layout.size)?;

4
src/librustc_mir/interpret/machine.rs
View File

@ -7,7 +7,7 @@ use std::hash::Hash;
use rustc::hir::def_id::DefId;
use rustc::mir;
use rustc::ty::{self, TyCtxt};
use rustc::ty::{self, Ty, TyCtxt};
use super::{
Allocation, AllocId, InterpResult, Scalar, AllocationExtra,
@ -176,7 +176,7 @@ pub trait Machine<'mir, 'tcx>: Sized {
bin_op: mir::BinOp,
left: ImmTy<'tcx, Self::PointerTag>,
right: ImmTy<'tcx, Self::PointerTag>,
) -> InterpResult<'tcx, (Scalar<Self::PointerTag>, bool)>;
) -> InterpResult<'tcx, (Scalar<Self::PointerTag>, bool, Ty<'tcx>)>;
/// Heap allocations via the `box` keyword.
fn box_alloc(

17
src/librustc_mir/interpret/operand.rs
View File

@ -108,7 +108,7 @@ impl<'tcx, Tag> Immediate<Tag> {
// as input for binary and cast operations.
#[derive(Copy, Clone, Debug)]
pub struct ImmTy<'tcx, Tag=()> {
pub imm: Immediate<Tag>,
pub(crate) imm: Immediate<Tag>,
pub layout: TyLayout<'tcx>,
}
@ -155,7 +155,7 @@ impl<Tag> Operand<Tag> {
#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
pub struct OpTy<'tcx, Tag=()> {
op: Operand<Tag>,
op: Operand<Tag>, // Keep this private, it helps enforce invariants
pub layout: TyLayout<'tcx>,
}
@ -187,13 +187,22 @@ impl<'tcx, Tag> From<ImmTy<'tcx, Tag>> for OpTy<'tcx, Tag> {
}
}
impl<'tcx, Tag: Copy> ImmTy<'tcx, Tag>
{
impl<'tcx, Tag: Copy> ImmTy<'tcx, Tag> {
#[inline]
pub fn from_scalar(val: Scalar<Tag>, layout: TyLayout<'tcx>) -> Self {
ImmTy { imm: val.into(), layout }
}
#[inline]
pub fn from_uint(i: impl Into<u128>, layout: TyLayout<'tcx>) -> Self {
Self::from_scalar(Scalar::from_uint(i, layout.size), layout)
}
#[inline]
pub fn from_int(i: impl Into<i128>, layout: TyLayout<'tcx>) -> Self {
Self::from_scalar(Scalar::from_int(i, layout.size), layout)
}
#[inline]
pub fn to_bits(self) -> InterpResult<'tcx, u128> {
self.to_scalar()?.to_bits(self.layout.size)

123
src/librustc_mir/interpret/operator.rs
View File

@ -1,5 +1,5 @@
use rustc::mir;
use rustc::ty::{self, layout::TyLayout};
use rustc::ty::{self, Ty, layout::{TyLayout, LayoutOf}};
use syntax::ast::FloatTy;
use rustc_apfloat::Float;
use rustc::mir::interpret::{InterpResult, Scalar};
@ -17,7 +17,12 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
right: ImmTy<'tcx, M::PointerTag>,
dest: PlaceTy<'tcx, M::PointerTag>,
) -> InterpResult<'tcx> {
let (val, overflowed) = self.binary_op(op, left, right)?;
let (val, overflowed, ty) = self.overflowing_binary_op(op, left, right)?;
debug_assert_eq!(
self.tcx.intern_tup(&[ty, self.tcx.types.bool]),
dest.layout.ty,
"type mismatch for result of {:?}", op,
);
let val = Immediate::ScalarPair(val.into(), Scalar::from_bool(overflowed).into());
self.write_immediate(val, dest)
}
@ -31,7 +36,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
right: ImmTy<'tcx, M::PointerTag>,
dest: PlaceTy<'tcx, M::PointerTag>,
) -> InterpResult<'tcx> {
let (val, _overflowed) = self.binary_op(op, left, right)?;
let (val, _overflowed, ty) = self.overflowing_binary_op(op, left, right)?;
assert_eq!(ty, dest.layout.ty, "type mismatch for result of {:?}", op);
self.write_scalar(val, dest)
}
}
@ -42,7 +48,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
bin_op: mir::BinOp,
l: char,
r: char,
) -> (Scalar<M::PointerTag>, bool) {
) -> (Scalar<M::PointerTag>, bool, Ty<'tcx>) {
use rustc::mir::BinOp::*;
let res = match bin_op {
@ -54,7 +60,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
Ge => l >= r,
_ => bug!("Invalid operation on char: {:?}", bin_op),
};
return (Scalar::from_bool(res), false);
return (Scalar::from_bool(res), false, self.tcx.types.bool);
}
fn binary_bool_op(
@ -62,7 +68,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
bin_op: mir::BinOp,
l: bool,
r: bool,
) -> (Scalar<M::PointerTag>, bool) {
) -> (Scalar<M::PointerTag>, bool, Ty<'tcx>) {
use rustc::mir::BinOp::*;
let res = match bin_op {
@ -77,32 +83,33 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
BitXor => l ^ r,
_ => bug!("Invalid operation on bool: {:?}", bin_op),
};
return (Scalar::from_bool(res), false);
return (Scalar::from_bool(res), false, self.tcx.types.bool);
}
fn binary_float_op<F: Float + Into<Scalar<M::PointerTag>>>(
&self,
bin_op: mir::BinOp,
ty: Ty<'tcx>,
l: F,
r: F,
) -> (Scalar<M::PointerTag>, bool) {
) -> (Scalar<M::PointerTag>, bool, Ty<'tcx>) {
use rustc::mir::BinOp::*;
let val = match bin_op {
Eq => Scalar::from_bool(l == r),
Ne => Scalar::from_bool(l != r),
Lt => Scalar::from_bool(l < r),
Le => Scalar::from_bool(l <= r),
Gt => Scalar::from_bool(l > r),
Ge => Scalar::from_bool(l >= r),
Add => (l + r).value.into(),
Sub => (l - r).value.into(),
Mul => (l * r).value.into(),
Div => (l / r).value.into(),
Rem => (l % r).value.into(),
let (val, ty) = match bin_op {
Eq => (Scalar::from_bool(l == r), self.tcx.types.bool),
Ne => (Scalar::from_bool(l != r), self.tcx.types.bool),
Lt => (Scalar::from_bool(l < r), self.tcx.types.bool),
Le => (Scalar::from_bool(l <= r), self.tcx.types.bool),
Gt => (Scalar::from_bool(l > r), self.tcx.types.bool),
Ge => (Scalar::from_bool(l >= r), self.tcx.types.bool),
Add => ((l + r).value.into(), ty),
Sub => ((l - r).value.into(), ty),
Mul => ((l * r).value.into(), ty),
Div => ((l / r).value.into(), ty),
Rem => ((l % r).value.into(), ty),
_ => bug!("invalid float op: `{:?}`", bin_op),
};
return (val, false);
return (val, false, ty);
}
fn binary_int_op(
@ -113,7 +120,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
left_layout: TyLayout<'tcx>,
r: u128,
right_layout: TyLayout<'tcx>,
) -> InterpResult<'tcx, (Scalar<M::PointerTag>, bool)> {
) -> InterpResult<'tcx, (Scalar<M::PointerTag>, bool, Ty<'tcx>)> {
use rustc::mir::BinOp::*;
// Shift ops can have an RHS with a different numeric type.
@ -142,7 +149,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
};
let truncated = self.truncate(result, left_layout);
return Ok((Scalar::from_uint(truncated, size), oflo));
return Ok((Scalar::from_uint(truncated, size), oflo, left_layout.ty));
}
// For the remaining ops, the types must be the same on both sides
@ -167,7 +174,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
if let Some(op) = op {
let l = self.sign_extend(l, left_layout) as i128;
let r = self.sign_extend(r, right_layout) as i128;
return Ok((Scalar::from_bool(op(&l, &r)), false));
return Ok((Scalar::from_bool(op(&l, &r)), false, self.tcx.types.bool));
}
let op: Option<fn(i128, i128) -> (i128, bool)> = match bin_op {
Div if r == 0 => throw_panic!(DivisionByZero),
@ -187,7 +194,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
Rem | Div => {
// int_min / -1
if r == -1 && l == (1 << (size.bits() - 1)) {
return Ok((Scalar::from_uint(l, size), true));
return Ok((Scalar::from_uint(l, size), true, left_layout.ty));
}
},
_ => {},
@ -202,25 +209,24 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
// this may be out-of-bounds for the result type, so we have to truncate ourselves
let result = result as u128;
let truncated = self.truncate(result, left_layout);
return Ok((Scalar::from_uint(truncated, size), oflo));
return Ok((Scalar::from_uint(truncated, size), oflo, left_layout.ty));
}
}
let size = left_layout.size;
// only ints left
let val = match bin_op {
Eq => Scalar::from_bool(l == r),
Ne => Scalar::from_bool(l != r),
let (val, ty) = match bin_op {
Eq => (Scalar::from_bool(l == r), self.tcx.types.bool),
Ne => (Scalar::from_bool(l != r), self.tcx.types.bool),
Lt => Scalar::from_bool(l < r),
Le => Scalar::from_bool(l <= r),
Gt => Scalar::from_bool(l > r),
Ge => Scalar::from_bool(l >= r),
Lt => (Scalar::from_bool(l < r), self.tcx.types.bool),
Le => (Scalar::from_bool(l <= r), self.tcx.types.bool),
Gt => (Scalar::from_bool(l > r), self.tcx.types.bool),
Ge => (Scalar::from_bool(l >= r), self.tcx.types.bool),
BitOr => Scalar::from_uint(l | r, size),
BitAnd => Scalar::from_uint(l & r, size),
BitXor => Scalar::from_uint(l ^ r, size),
BitOr => (Scalar::from_uint(l | r, size), left_layout.ty),
BitAnd => (Scalar::from_uint(l & r, size), left_layout.ty),
BitXor => (Scalar::from_uint(l ^ r, size), left_layout.ty),
Add | Sub | Mul | Rem | Div => {
debug_assert!(!left_layout.abi.is_signed());
@ -236,7 +242,11 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
};
let (result, oflo) = op(l, r);
let truncated = self.truncate(result, left_layout);
return Ok((Scalar::from_uint(truncated, size), oflo || truncated != result));
return Ok((
Scalar::from_uint(truncated, size),
oflo || truncated != result,
left_layout.ty,
));
}
_ => {
@ -250,17 +260,17 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
};
Ok((val, false))
Ok((val, false, ty))
}
/// Returns the result of the specified operation and whether it overflowed.
#[inline]
pub fn binary_op(
/// Returns the result of the specified operation, whether it overflowed, and
/// the result type.
pub fn overflowing_binary_op(
&self,
bin_op: mir::BinOp,
left: ImmTy<'tcx, M::PointerTag>,
right: ImmTy<'tcx, M::PointerTag>,
) -> InterpResult<'tcx, (Scalar<M::PointerTag>, bool)> {
) -> InterpResult<'tcx, (Scalar<M::PointerTag>, bool, Ty<'tcx>)> {
trace!("Running binary op {:?}: {:?} ({:?}), {:?} ({:?})",
bin_op, *left, left.layout.ty, *right, right.layout.ty);
@ -279,11 +289,14 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
ty::Float(fty) => {
assert_eq!(left.layout.ty, right.layout.ty);
let ty = left.layout.ty;
let left = left.to_scalar()?;
let right = right.to_scalar()?;
Ok(match fty {
FloatTy::F32 => self.binary_float_op(bin_op, left.to_f32()?, right.to_f32()?),
FloatTy::F64 => self.binary_float_op(bin_op, left.to_f64()?, right.to_f64()?),
FloatTy::F32 =>
self.binary_float_op(bin_op, ty, left.to_f32()?, right.to_f32()?),
FloatTy::F64 =>
self.binary_float_op(bin_op, ty, left.to_f64()?, right.to_f64()?),
})
}
_ if left.layout.ty.is_integral() => {
@ -312,11 +325,23 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
}
/// Typed version of `checked_binary_op`, returning an `ImmTy`. Also ignores overflows.
#[inline]
pub fn binary_op(
&self,
bin_op: mir::BinOp,
left: ImmTy<'tcx, M::PointerTag>,
right: ImmTy<'tcx, M::PointerTag>,
) -> InterpResult<'tcx, ImmTy<'tcx, M::PointerTag>> {
let (val, _overflow, ty) = self.overflowing_binary_op(bin_op, left, right)?;
Ok(ImmTy::from_scalar(val, self.layout_of(ty)?))
}
pub fn unary_op(
&self,
un_op: mir::UnOp,
val: ImmTy<'tcx, M::PointerTag>,
) -> InterpResult<'tcx, Scalar<M::PointerTag>> {
) -> InterpResult<'tcx, ImmTy<'tcx, M::PointerTag>> {
use rustc::mir::UnOp::*;
let layout = val.layout;
@ -330,7 +355,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
Not => !val,
_ => bug!("Invalid bool op {:?}", un_op)
};
Ok(Scalar::from_bool(res))
Ok(ImmTy::from_scalar(Scalar::from_bool(res), self.layout_of(self.tcx.types.bool)?))
}
ty::Float(fty) => {
let res = match (un_op, fty) {
@ -338,7 +363,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
(Neg, FloatTy::F64) => Scalar::from_f64(-val.to_f64()?),
_ => bug!("Invalid float op {:?}", un_op)
};
Ok(res)
Ok(ImmTy::from_scalar(res, layout))
}
_ => {
assert!(layout.ty.is_integral());
@ -351,7 +376,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
};
// res needs tuncating
Ok(Scalar::from_uint(self.truncate(res, layout), layout.size))
Ok(ImmTy::from_uint(self.truncate(res, layout), layout))
}
}
}

2
src/librustc_mir/interpret/place.rs
View File

@ -45,7 +45,7 @@ pub enum Place<Tag=(), Id=AllocId> {
#[derive(Copy, Clone, Debug)]
pub struct PlaceTy<'tcx, Tag=()> {
place: Place<Tag>,
place: Place<Tag>, // Keep this private, it helps enforce invariants
pub layout: TyLayout<'tcx>,
}

3
src/librustc_mir/interpret/step.rs
View File

@ -177,7 +177,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
// The operand always has the same type as the result.
let val = self.read_immediate(self.eval_operand(operand, Some(dest.layout))?)?;
let val = self.unary_op(un_op, val)?;
self.write_scalar(val, dest)?;
assert_eq!(val.layout, dest.layout, "layout mismatch for result of {:?}", un_op);
self.write_immediate(*val, dest)?;
}
Aggregate(ref kind, ref operands) => {

9
src/librustc_mir/interpret/terminator.rs
View File

@ -7,7 +7,7 @@ use syntax::source_map::Span;
use rustc_target::spec::abi::Abi;
use super::{
InterpResult, PointerArithmetic, Scalar,
InterpResult, PointerArithmetic,
InterpCx, Machine, OpTy, ImmTy, PlaceTy, MPlaceTy, StackPopCleanup, FnVal,
};
@ -50,11 +50,10 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
for (index, &const_int) in values.iter().enumerate() {
// Compare using binary_op, to also support pointer values
let const_int = Scalar::from_uint(const_int, discr.layout.size);
let (res, _) = self.binary_op(mir::BinOp::Eq,
let res = self.overflowing_binary_op(mir::BinOp::Eq,
discr,
ImmTy::from_scalar(const_int, discr.layout),
)?;
ImmTy::from_uint(const_int, discr.layout),
)?.0;
if res.to_bool()? {
target_block = targets[index];
break;

37
src/librustc_mir/transform/const_prop.rs
View File

@ -19,7 +19,7 @@ use syntax_pos::{Span, DUMMY_SP};
use rustc::ty::subst::InternalSubsts;
use rustc_data_structures::indexed_vec::IndexVec;
use rustc::ty::layout::{
LayoutOf, TyLayout, LayoutError, HasTyCtxt, TargetDataLayout, HasDataLayout, Size,
LayoutOf, TyLayout, LayoutError, HasTyCtxt, TargetDataLayout, HasDataLayout,
};
use crate::interpret::{
@ -396,17 +396,10 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
if let ty::Slice(_) = mplace.layout.ty.sty {
let len = mplace.meta.unwrap().to_usize(&self.ecx).unwrap();
Some(ImmTy {
imm: Immediate::Scalar(
Scalar::from_uint(
len,
Size::from_bits(
self.tcx.sess.target.usize_ty.bit_width().unwrap() as u64
)
).into(),
),
layout: self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?,
}.into())
Some(ImmTy::from_uint(
len,
self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?,
).into())
} else {
trace!("not slice: {:?}", mplace.layout.ty.sty);
None
@ -414,12 +407,10 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
},
Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
type_size_of(self.tcx, self.param_env, ty).and_then(|n| Some(
ImmTy {
imm: Immediate::Scalar(
Scalar::from_uint(n, self.tcx.data_layout.pointer_size).into()
),
layout: self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?,
}.into()
ImmTy::from_uint(
n,
self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?,
).into()
))
}
Rvalue::UnaryOp(op, ref arg) => {
@ -452,11 +443,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
// Now run the actual operation.
this.ecx.unary_op(op, prim)
})?;
let res = ImmTy {
imm: Immediate::Scalar(val.into()),
layout: place_layout,
};
Some(res.into())
Some(val.into())
}
Rvalue::CheckedBinaryOp(op, ref left, ref right) |
Rvalue::BinaryOp(op, ref left, ref right) => {
@ -510,8 +497,8 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
this.ecx.read_immediate(left)
})?;
trace!("const evaluating {:?} for {:?} and {:?}", op, left, right);
let (val, overflow) = self.use_ecx(source_info, |this| {
this.ecx.binary_op(op, l, r)
let (val, overflow, _ty) = self.use_ecx(source_info, |this| {
this.ecx.overflowing_binary_op(op, l, r)
})?;
let val = if let Rvalue::CheckedBinaryOp(..) = *rvalue {
Immediate::ScalarPair(