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Extend the MIR validator to check many more things around rvalues.

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This commit is contained in:
Jakob Degen 2022-03-24 22:30:23 -04:00
parent 634369170a
commit 9ac5e986ed
3 changed files with 182 additions and 60 deletions
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200
compiler/rustc_const_eval/src/transform/validate.rs
View File

@ -4,14 +4,13 @@ use rustc_index::bit_set::BitSet;
use rustc_infer::infer::TyCtxtInferExt;
use rustc_middle::mir::interpret::Scalar;
use rustc_middle::mir::visit::{PlaceContext, Visitor};
use rustc_middle::mir::{traversal, Place};
use rustc_middle::mir::{
AggregateKind, BasicBlock, Body, BorrowKind, Local, Location, MirPass, MirPhase, Operand,
PlaceElem, PlaceRef, ProjectionElem, Rvalue, SourceScope, Statement, StatementKind, Terminator,
TerminatorKind, START_BLOCK,
traversal, AggregateKind, BasicBlock, BinOp, Body, BorrowKind, Local, Location, MirPass,
MirPhase, Operand, Place, PlaceElem, PlaceRef, ProjectionElem, Rvalue, SourceScope, Statement,
StatementKind, Terminator, TerminatorKind, UnOp, START_BLOCK,
};
use rustc_middle::ty::fold::BottomUpFolder;
use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt, TypeFoldable};
use rustc_middle::ty::{self, InstanceDef, ParamEnv, Ty, TyCtxt, TypeFoldable};
use rustc_mir_dataflow::impls::MaybeStorageLive;
use rustc_mir_dataflow::storage::AlwaysLiveLocals;
use rustc_mir_dataflow::{Analysis, ResultsCursor};
@ -36,6 +35,13 @@ pub struct Validator {
impl<'tcx> MirPass<'tcx> for Validator {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
// FIXME(JakobDegen): These bodies never instantiated in codegend anyway, so it's not
// terribly important that they pass the validator. However, I think other passes might
// still see them, in which case they might be surprised. It would probably be better if we
// didn't put this through the MIR pipeline at all.
if matches!(body.source.instance, InstanceDef::Intrinsic(..) | InstanceDef::Virtual(..)) {
return;
}
let def_id = body.source.def_id();
let param_env = tcx.param_env(def_id);
let mir_phase = self.mir_phase;
@ -248,6 +254,147 @@ 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)*) {
self.fail(location, format!($text, $t));
}
};
}
match rvalue {
Rvalue::Use(_) => {}
Rvalue::Aggregate(agg_kind, _) => {
let disallowed = match **agg_kind {
AggregateKind::Array(..) => false,
AggregateKind::Generator(..) => self.mir_phase >= MirPhase::GeneratorsLowered,
_ => self.mir_phase >= MirPhase::Deaggregated,
};
if disallowed {
self.fail(
location,
format!("{:?} have been lowered to field assignments", rvalue),
)
}
}
Rvalue::Ref(_, BorrowKind::Shallow, _) => {
if self.mir_phase >= MirPhase::DropsLowered {
self.fail(
location,
"`Assign` statement with a `Shallow` borrow should have been removed after drop lowering phase",
);
}
}
Rvalue::Len(p) => {
let pty = p.ty(&self.body.local_decls, self.tcx).ty;
check_kinds!(
pty,
"Cannot compute length of non-array type {:?}",
ty::Array(..) | ty::Slice(..)
);
}
Rvalue::BinaryOp(op, vals) | Rvalue::CheckedBinaryOp(op, vals) => {
use BinOp::*;
let a = vals.0.ty(&self.body.local_decls, self.tcx);
let b = vals.1.ty(&self.body.local_decls, self.tcx);
match op {
Offset => {
check_kinds!(a, "Cannot offset non-pointer type {:?}", ty::RawPtr(..));
if b != self.tcx.types.isize && b != self.tcx.types.usize {
self.fail(location, format!("Cannot offset by non-isize type {:?}", b));
}
}
Eq | Lt | Le | Ne | Ge | Gt => {
for x in [a, b] {
check_kinds!(
x,
"Cannot compare type {:?}",
ty::Bool
| ty::Char
| ty::Int(..)
| ty::Uint(..)
| ty::Float(..)
| ty::RawPtr(..)
| ty::FnPtr(..)
)
}
// None of the possible types have lifetimes, so we can just compare
// directly
if a != b {
self.fail(
location,
format!("Cannot compare unequal types {:?} and {:?}", a, b),
);
}
}
Shl | Shr => {
for x in [a, b] {
check_kinds!(
x,
"Cannot shift non-integer type {:?}",
ty::Uint(..) | ty::Int(..)
)
}
}
BitAnd | BitOr | BitXor => {
for x in [a, b] {
check_kinds!(
x,
"Cannot perform bitwise 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 op on type {:?}",
ty::Uint(..) | ty::Int(..) | ty::Float(..)
)
}
if a != b {
self.fail(
location,
format!("Cannot perform op on unequal types {:?} and {:?}", a, b),
);
}
}
}
}
Rvalue::UnaryOp(op, operand) => {
let a = operand.ty(&self.body.local_decls, self.tcx);
match op {
UnOp::Neg => {
check_kinds!(a, "Cannot negate type {:?}", ty::Int(..) | ty::Float(..))
}
UnOp::Not => {
check_kinds!(
a,
"Cannot binary not type {:?}",
ty::Int(..) | ty::Uint(..) | ty::Bool
);
}
}
}
Rvalue::ShallowInitBox(operand, _) => {
let a = operand.ty(&self.body.local_decls, self.tcx);
check_kinds!(a, "Cannot shallow init type {:?}", ty::RawPtr(..));
}
_ => {}
}
self.super_rvalue(rvalue, location);
}
fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
match &statement.kind {
StatementKind::Assign(box (dest, rvalue)) => {
@ -265,41 +412,16 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
),
);
}
match rvalue {
// The sides of an assignment must not alias. Currently this just checks whether the places
// are identical.
Rvalue::Use(Operand::Copy(src) | Operand::Move(src)) => {
if dest == src {
self.fail(
location,
"encountered `Assign` statement with overlapping memory",
);
}
// FIXME(JakobDegen): Check this for all rvalues, not just this one.
if let Rvalue::Use(Operand::Copy(src) | Operand::Move(src)) = rvalue {
// The sides of an assignment must not alias. Currently this just checks whether
// the places are identical.
if dest == src {
self.fail(
location,
"encountered `Assign` statement with overlapping memory",
);
}
Rvalue::Aggregate(agg_kind, _) => {
let disallowed = match **agg_kind {
AggregateKind::Array(..) => false,
AggregateKind::Generator(..) => {
self.mir_phase >= MirPhase::GeneratorsLowered
}
_ => self.mir_phase >= MirPhase::Deaggregated,
};
if disallowed {
self.fail(
location,
format!("{:?} have been lowered to field assignments", rvalue),
)
}
}
Rvalue::Ref(_, BorrowKind::Shallow, _) => {
if self.mir_phase >= MirPhase::DropsLowered {
self.fail(
location,
"`Assign` statement with a `Shallow` borrow should have been removed after drop lowering phase",
);
}
}
_ => {}
}
}
StatementKind::AscribeUserType(..) => {

2
src/test/mir-opt/lower_intrinsics.rs
View File

@ -3,7 +3,7 @@
#![crate_type = "lib"]
// EMIT_MIR lower_intrinsics.wrapping.LowerIntrinsics.diff
pub fn wrapping<T: Copy>(a: T, b: T) {
pub fn wrapping(a: i32, b: i32) {
let _x = core::intrinsics::wrapping_add(a, b);
let _y = core::intrinsics::wrapping_sub(a, b);
let _z = core::intrinsics::wrapping_mul(a, b);

40
src/test/mir-opt/lower_intrinsics.wrapping.LowerIntrinsics.diff
View File

@ -1,23 +1,23 @@
- // MIR for `wrapping` before LowerIntrinsics
+ // MIR for `wrapping` after LowerIntrinsics
fn wrapping(_1: T, _2: T) -> () {
debug a => _1; // in scope 0 at $DIR/lower_intrinsics.rs:6:26: 6:27
debug b => _2; // in scope 0 at $DIR/lower_intrinsics.rs:6:32: 6:33
let mut _0: (); // return place in scope 0 at $DIR/lower_intrinsics.rs:6:38: 6:38
let _3: T; // in scope 0 at $DIR/lower_intrinsics.rs:7:9: 7:11
let mut _4: T; // in scope 0 at $DIR/lower_intrinsics.rs:7:45: 7:46
let mut _5: T; // in scope 0 at $DIR/lower_intrinsics.rs:7:48: 7:49
let mut _7: T; // in scope 0 at $DIR/lower_intrinsics.rs:8:45: 8:46
let mut _8: T; // in scope 0 at $DIR/lower_intrinsics.rs:8:48: 8:49
let mut _10: T; // in scope 0 at $DIR/lower_intrinsics.rs:9:45: 9:46
let mut _11: T; // in scope 0 at $DIR/lower_intrinsics.rs:9:48: 9:49
fn wrapping(_1: i32, _2: i32) -> () {
debug a => _1; // in scope 0 at $DIR/lower_intrinsics.rs:6:17: 6:18
debug b => _2; // in scope 0 at $DIR/lower_intrinsics.rs:6:25: 6:26
let mut _0: (); // return place in scope 0 at $DIR/lower_intrinsics.rs:6:33: 6:33
let _3: i32; // in scope 0 at $DIR/lower_intrinsics.rs:7:9: 7:11
let mut _4: i32; // in scope 0 at $DIR/lower_intrinsics.rs:7:45: 7:46
let mut _5: i32; // in scope 0 at $DIR/lower_intrinsics.rs:7:48: 7:49
let mut _7: i32; // in scope 0 at $DIR/lower_intrinsics.rs:8:45: 8:46
let mut _8: i32; // in scope 0 at $DIR/lower_intrinsics.rs:8:48: 8:49
let mut _10: i32; // in scope 0 at $DIR/lower_intrinsics.rs:9:45: 9:46
let mut _11: i32; // in scope 0 at $DIR/lower_intrinsics.rs:9:48: 9:49
scope 1 {
debug _x => _3; // in scope 1 at $DIR/lower_intrinsics.rs:7:9: 7:11
let _6: T; // in scope 1 at $DIR/lower_intrinsics.rs:8:9: 8:11
let _6: i32; // in scope 1 at $DIR/lower_intrinsics.rs:8:9: 8:11
scope 2 {
debug _y => _6; // in scope 2 at $DIR/lower_intrinsics.rs:8:9: 8:11
let _9: T; // in scope 2 at $DIR/lower_intrinsics.rs:9:9: 9:11
let _9: i32; // in scope 2 at $DIR/lower_intrinsics.rs:9:9: 9:11
scope 3 {
debug _z => _9; // in scope 3 at $DIR/lower_intrinsics.rs:9:9: 9:11
}
@ -30,10 +30,10 @@
_4 = _1; // scope 0 at $DIR/lower_intrinsics.rs:7:45: 7:46
StorageLive(_5); // scope 0 at $DIR/lower_intrinsics.rs:7:48: 7:49
_5 = _2; // scope 0 at $DIR/lower_intrinsics.rs:7:48: 7:49
- _3 = wrapping_add::<T>(move _4, move _5) -> bb1; // scope 0 at $DIR/lower_intrinsics.rs:7:14: 7:50
- _3 = wrapping_add::<i32>(move _4, move _5) -> bb1; // scope 0 at $DIR/lower_intrinsics.rs:7:14: 7:50
- // mir::Constant
- // + span: $DIR/lower_intrinsics.rs:7:14: 7:44
- // + literal: Const { ty: extern "rust-intrinsic" fn(T, T) -> T {wrapping_add::<T>}, val: Value(Scalar(<ZST>)) }
- // + literal: Const { ty: extern "rust-intrinsic" fn(i32, i32) -> i32 {wrapping_add::<i32>}, val: Value(Scalar(<ZST>)) }
+ _3 = Add(move _4, move _5); // scope 0 at $DIR/lower_intrinsics.rs:7:14: 7:50
+ goto -> bb1; // scope 0 at $DIR/lower_intrinsics.rs:7:14: 7:50
}
@ -46,10 +46,10 @@
_7 = _1; // scope 1 at $DIR/lower_intrinsics.rs:8:45: 8:46
StorageLive(_8); // scope 1 at $DIR/lower_intrinsics.rs:8:48: 8:49
_8 = _2; // scope 1 at $DIR/lower_intrinsics.rs:8:48: 8:49
- _6 = wrapping_sub::<T>(move _7, move _8) -> bb2; // scope 1 at $DIR/lower_intrinsics.rs:8:14: 8:50
- _6 = wrapping_sub::<i32>(move _7, move _8) -> bb2; // scope 1 at $DIR/lower_intrinsics.rs:8:14: 8:50
- // mir::Constant
- // + span: $DIR/lower_intrinsics.rs:8:14: 8:44
- // + literal: Const { ty: extern "rust-intrinsic" fn(T, T) -> T {wrapping_sub::<T>}, val: Value(Scalar(<ZST>)) }
- // + literal: Const { ty: extern "rust-intrinsic" fn(i32, i32) -> i32 {wrapping_sub::<i32>}, val: Value(Scalar(<ZST>)) }
+ _6 = Sub(move _7, move _8); // scope 1 at $DIR/lower_intrinsics.rs:8:14: 8:50
+ goto -> bb2; // scope 1 at $DIR/lower_intrinsics.rs:8:14: 8:50
}
@ -62,10 +62,10 @@
_10 = _1; // scope 2 at $DIR/lower_intrinsics.rs:9:45: 9:46
StorageLive(_11); // scope 2 at $DIR/lower_intrinsics.rs:9:48: 9:49
_11 = _2; // scope 2 at $DIR/lower_intrinsics.rs:9:48: 9:49
- _9 = wrapping_mul::<T>(move _10, move _11) -> bb3; // scope 2 at $DIR/lower_intrinsics.rs:9:14: 9:50
- _9 = wrapping_mul::<i32>(move _10, move _11) -> bb3; // scope 2 at $DIR/lower_intrinsics.rs:9:14: 9:50
- // mir::Constant
- // + span: $DIR/lower_intrinsics.rs:9:14: 9:44
- // + literal: Const { ty: extern "rust-intrinsic" fn(T, T) -> T {wrapping_mul::<T>}, val: Value(Scalar(<ZST>)) }
- // + literal: Const { ty: extern "rust-intrinsic" fn(i32, i32) -> i32 {wrapping_mul::<i32>}, val: Value(Scalar(<ZST>)) }
+ _9 = Mul(move _10, move _11); // scope 2 at $DIR/lower_intrinsics.rs:9:14: 9:50
+ goto -> bb3; // scope 2 at $DIR/lower_intrinsics.rs:9:14: 9:50
}
@ -73,7 +73,7 @@
bb3: {
StorageDead(_11); // scope 2 at $DIR/lower_intrinsics.rs:9:49: 9:50
StorageDead(_10); // scope 2 at $DIR/lower_intrinsics.rs:9:49: 9:50
_0 = const (); // scope 0 at $DIR/lower_intrinsics.rs:6:38: 10:2
_0 = const (); // scope 0 at $DIR/lower_intrinsics.rs:6:33: 10:2
StorageDead(_9); // scope 2 at $DIR/lower_intrinsics.rs:10:1: 10:2
StorageDead(_6); // scope 1 at $DIR/lower_intrinsics.rs:10:1: 10:2
StorageDead(_3); // scope 0 at $DIR/lower_intrinsics.rs:10:1: 10:2