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Rollup merge of #102675 - ouz-a:mir-technical-debt, r=oli-obk

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Remove `mir::CastKind::Misc`

As discussed in #97649 `mir::CastKind::Misc` is not clear, this PR addresses that by creating a new enum variant for every valid cast.

r? ````@oli-obk````
This commit is contained in:
Matthias Krüger 2022-10-08 14:38:18 +02:00 • committed by GitHub
commit c731646d6a
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GPG key ID: 4AEE18F83AFDEB23
25 changed files with 190 additions and 57 deletions
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99
compiler/rustc_borrowck/src/type_check/mod.rs
View file

@ -2209,25 +2209,104 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
}
}
}
CastKind::Misc => {
CastKind::IntToInt => {
let ty_from = op.ty(body, tcx);
let cast_ty_from = CastTy::from_ty(ty_from);
let cast_ty_to = CastTy::from_ty(*ty);
// Misc casts are either between floats and ints, or one ptr type to another.
match (cast_ty_from, cast_ty_to) {
(
Some(CastTy::Int(_) | CastTy::Float),
Some(CastTy::Int(_) | CastTy::Float),
)
| (Some(CastTy::Ptr(_) | CastTy::FnPtr), Some(CastTy::Ptr(_))) => (),
(Some(CastTy::Int(_)), Some(CastTy::Int(_))) => (),
_ => {
span_mirbug!(
self,
rvalue,
"Invalid Misc cast {:?} -> {:?}",
"Invalid IntToInt cast {:?} -> {:?}",
ty_from,
ty,
ty
)
}
}
}
CastKind::IntToFloat => {
let ty_from = op.ty(body, tcx);
let cast_ty_from = CastTy::from_ty(ty_from);
let cast_ty_to = CastTy::from_ty(*ty);
match (cast_ty_from, cast_ty_to) {
(Some(CastTy::Int(_)), Some(CastTy::Float)) => (),
_ => {
span_mirbug!(
self,
rvalue,
"Invalid IntToFloat cast {:?} -> {:?}",
ty_from,
ty
)
}
}
}
CastKind::FloatToInt => {
let ty_from = op.ty(body, tcx);
let cast_ty_from = CastTy::from_ty(ty_from);
let cast_ty_to = CastTy::from_ty(*ty);
match (cast_ty_from, cast_ty_to) {
(Some(CastTy::Float), Some(CastTy::Int(_))) => (),
_ => {
span_mirbug!(
self,
rvalue,
"Invalid FloatToInt cast {:?} -> {:?}",
ty_from,
ty
)
}
}
}
CastKind::FloatToFloat => {
let ty_from = op.ty(body, tcx);
let cast_ty_from = CastTy::from_ty(ty_from);
let cast_ty_to = CastTy::from_ty(*ty);
match (cast_ty_from, cast_ty_to) {
(Some(CastTy::Float), Some(CastTy::Float)) => (),
_ => {
span_mirbug!(
self,
rvalue,
"Invalid FloatToFloat cast {:?} -> {:?}",
ty_from,
ty
)
}
}
}
CastKind::FnPtrToPtr => {
let ty_from = op.ty(body, tcx);
let cast_ty_from = CastTy::from_ty(ty_from);
let cast_ty_to = CastTy::from_ty(*ty);
match (cast_ty_from, cast_ty_to) {
(Some(CastTy::FnPtr), Some(CastTy::Ptr(_))) => (),
_ => {
span_mirbug!(
self,
rvalue,
"Invalid FnPtrToPtr cast {:?} -> {:?}",
ty_from,
ty
)
}
}
}
CastKind::PtrToPtr => {
let ty_from = op.ty(body, tcx);
let cast_ty_from = CastTy::from_ty(ty_from);
let cast_ty_to = CastTy::from_ty(*ty);
match (cast_ty_from, cast_ty_to) {
(Some(CastTy::Ptr(_)), Some(CastTy::Ptr(_))) => (),
_ => {
span_mirbug!(
self,
rvalue,
"Invalid PtrToPtr cast {:?} -> {:?}",
ty_from,
ty
)
}
}

7
compiler/rustc_codegen_cranelift/src/base.rs
View file

@ -633,7 +633,12 @@ fn codegen_stmt<'tcx>(
lval.write_cvalue(fx, operand.cast_pointer_to(to_layout));
}
Rvalue::Cast(
CastKind::Misc
CastKind::IntToInt
| CastKind::FloatToFloat
| CastKind::FloatToInt
| CastKind::IntToFloat
| CastKind::FnPtrToPtr
| CastKind::PtrToPtr
| CastKind::PointerExposeAddress
| CastKind::PointerFromExposedAddress,
ref operand,

11
compiler/rustc_codegen_cranelift/src/constant.rs
View file

@ -490,7 +490,16 @@ pub(crate) fn mir_operand_get_const_val<'tcx>(
match &stmt.kind {
StatementKind::Assign(local_and_rvalue) if &local_and_rvalue.0 == place => {
match &local_and_rvalue.1 {
Rvalue::Cast(CastKind::Misc, operand, ty) => {
Rvalue::Cast(
CastKind::IntToInt
| CastKind::FloatToFloat
| CastKind::FloatToInt
| CastKind::IntToFloat
| CastKind::FnPtrToPtr
| CastKind::PtrToPtr,
operand,
ty,
) => {
if computed_const_val.is_some() {
return None; // local assigned twice
}

10
compiler/rustc_codegen_ssa/src/mir/rvalue.rs
View file

@ -250,7 +250,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
OperandValue::Pair(lldata, llextra)
}
mir::CastKind::Pointer(PointerCast::MutToConstPointer)
| mir::CastKind::Misc
| mir::CastKind::PtrToPtr
if bx.cx().is_backend_scalar_pair(operand.layout) =>
{
if let OperandValue::Pair(data_ptr, meta) = operand.val {
@ -290,7 +290,13 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
mir::CastKind::Pointer(
PointerCast::MutToConstPointer | PointerCast::ArrayToPointer,
)
| mir::CastKind::Misc
| mir::CastKind::IntToInt
| mir::CastKind::FloatToInt
| mir::CastKind::FloatToFloat
| mir::CastKind::IntToFloat
| mir::CastKind::PtrToPtr
| mir::CastKind::FnPtrToPtr
// Since int2ptr can have arbitrary integer types as input (so we have to do
// sign extension and all that), it is currently best handled in the same code
// path as the other integer-to-X casts.

4
compiler/rustc_const_eval/src/interpret/cast.rs
View file

@ -42,8 +42,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
let res = self.pointer_from_exposed_address_cast(&src, cast_ty)?;
self.write_immediate(res, dest)?;
}
Misc => {
// FIXME: We shouldn't use `misc_cast` for these but handle them separately.
IntToInt | FloatToInt | FloatToFloat | IntToFloat | FnPtrToPtr | PtrToPtr => {
let src = self.read_immediate(src)?;
let res = self.misc_cast(&src, cast_ty)?;
self.write_immediate(res, dest)?;

2
compiler/rustc_const_eval/src/transform/check_consts/check.rs
View file

@ -553,7 +553,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
unimplemented!()
}
Rvalue::Cast(CastKind::Misc, _, _) => {}
Rvalue::Cast(_, _, _) => {}
Rvalue::NullaryOp(NullOp::SizeOf | NullOp::AlignOf, _) => {}
Rvalue::ShallowInitBox(_, _) => {}

16
compiler/rustc_const_eval/src/transform/validate.rs
View file

@ -557,7 +557,14 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
}
Rvalue::Cast(kind, operand, target_type) => {
match kind {
CastKind::Misc => {
CastKind::DynStar => {
// FIXME(dyn-star): make sure nothing needs to be done here.
}
// Nothing to check here
CastKind::PointerFromExposedAddress
| CastKind::PointerExposeAddress
| CastKind::Pointer(_) => {}
_ => {
let op_ty = operand.ty(self.body, self.tcx);
if op_ty.is_enum() {
self.fail(
@ -568,13 +575,6 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
);
}
}
CastKind::DynStar => {
// FIXME(dyn-star): make sure nothing needs to be done here.
}
// Nothing to check here
CastKind::PointerFromExposedAddress
| CastKind::PointerExposeAddress
| CastKind::Pointer(_) => {}
}
}
Rvalue::Repeat(_, _)

9
compiler/rustc_middle/src/mir/mod.rs
View file

@ -1834,7 +1834,14 @@ impl<'tcx> Rvalue<'tcx> {
| Rvalue::AddressOf(_, _)
| Rvalue::Len(_)
| Rvalue::Cast(
CastKind::Misc | CastKind::Pointer(_) | CastKind::PointerFromExposedAddress,
CastKind::IntToInt
| CastKind::FloatToInt
| CastKind::FloatToFloat
| CastKind::IntToFloat
| CastKind::FnPtrToPtr
| CastKind::PtrToPtr
| CastKind::Pointer(_)
| CastKind::PointerFromExposedAddress,
_,
_,
)

8
compiler/rustc_middle/src/mir/syntax.rs
View file

@ -1149,8 +1149,12 @@ pub enum CastKind {
Pointer(PointerCast),
/// Cast into a dyn* object.
DynStar,
/// Remaining unclassified casts.
Misc,
IntToInt,
FloatToInt,
FloatToFloat,
IntToFloat,
PtrToPtr,
FnPtrToPtr,
}
#[derive(Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)]

26
compiler/rustc_middle/src/ty/cast.rs
View file

@ -2,6 +2,7 @@
// typeck and codegen.
use crate::ty::{self, Ty};
use rustc_middle::mir;
use rustc_macros::HashStable;
@ -75,3 +76,28 @@ impl<'tcx> CastTy<'tcx> {
}
}
}
/// Returns `mir::CastKind` from the given parameters.
pub fn mir_cast_kind<'tcx>(from_ty: Ty<'tcx>, cast_ty: Ty<'tcx>) -> mir::CastKind {
let from = CastTy::from_ty(from_ty);
let cast = CastTy::from_ty(cast_ty);
let cast_kind = match (from, cast) {
(Some(CastTy::Ptr(_) | CastTy::FnPtr), Some(CastTy::Int(_))) => {
mir::CastKind::PointerExposeAddress
}
(Some(CastTy::Int(_)), Some(CastTy::Ptr(_))) => mir::CastKind::PointerFromExposedAddress,
(_, Some(CastTy::DynStar)) => mir::CastKind::DynStar,
(Some(CastTy::Int(_)), Some(CastTy::Int(_))) => mir::CastKind::IntToInt,
(Some(CastTy::FnPtr), Some(CastTy::Ptr(_))) => mir::CastKind::FnPtrToPtr,
(Some(CastTy::Float), Some(CastTy::Int(_))) => mir::CastKind::FloatToInt,
(Some(CastTy::Int(_)), Some(CastTy::Float)) => mir::CastKind::IntToFloat,
(Some(CastTy::Float), Some(CastTy::Float)) => mir::CastKind::FloatToFloat,
(Some(CastTy::Ptr(_)), Some(CastTy::Ptr(_))) => mir::CastKind::PtrToPtr,
(_, _) => {
bug!("Attempting to cast non-castable types {:?} and {:?}", from_ty, cast_ty)
}
};
cast_kind
}

13
compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
View file

@ -12,7 +12,7 @@ use rustc_middle::mir::AssertKind;
use rustc_middle::mir::Place;
use rustc_middle::mir::*;
use rustc_middle::thir::*;
use rustc_middle::ty::cast::CastTy;
use rustc_middle::ty::cast::{mir_cast_kind, CastTy};
use rustc_middle::ty::{self, Ty, UpvarSubsts};
use rustc_span::Span;
@ -217,16 +217,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let from_ty = CastTy::from_ty(ty);
let cast_ty = CastTy::from_ty(expr.ty);
debug!("ExprKind::Cast from_ty={from_ty:?}, cast_ty={:?}/{cast_ty:?}", expr.ty,);
let cast_kind = match (from_ty, cast_ty) {
(Some(CastTy::Ptr(_) | CastTy::FnPtr), Some(CastTy::Int(_))) => {
CastKind::PointerExposeAddress
}
(Some(CastTy::Int(_)), Some(CastTy::Ptr(_))) => {
CastKind::PointerFromExposedAddress
}
(_, Some(CastTy::DynStar)) => CastKind::DynStar,
(_, _) => CastKind::Misc,
};
let cast_kind = mir_cast_kind(ty, expr.ty);
block.and(Rvalue::Cast(cast_kind, source, expr.ty))
}
ExprKind::Pointer { cast, source } => {

3
compiler/rustc_mir_dataflow/src/elaborate_drops.rs
View file

@ -823,9 +823,10 @@ where
// tmp = &raw mut P;
// cur = tmp as *mut T;
// end = Offset(cur, len);
let mir_cast_kind = ty::cast::mir_cast_kind(iter_ty, tmp_ty);
vec![
self.assign(tmp, Rvalue::AddressOf(Mutability::Mut, self.place)),
self.assign(cur, Rvalue::Cast(CastKind::Misc, Operand::Move(tmp), iter_ty)),
self.assign(cur, Rvalue::Cast(mir_cast_kind, Operand::Move(tmp), iter_ty)),
self.assign(
length_or_end,
Rvalue::BinaryOp(