Miri core engine: use throw_ub instead of throw_panic

src/librustc/mir/interpret/error.rs

@@ -371,6 +371,14 @@ pub enum UndefinedBehaviorInfo {
  Unreachable,
  /// An enum discriminant was set to a value which was outside the range of valid values.
  InvalidDiscriminant(ScalarMaybeUndef),
+ /// A slice/array index projection went out-of-bounds.
+ BoundsCheckFailed { len: u64, index: u64 },
+ /// Something was divided by 0 (x / 0).
+ DivisionByZero,
+ /// Something was "remainded" by 0 (x % 0).
+ RemainderByZero,
+ /// Overflowing inbounds pointer arithmetic.
+ PointerArithOverflow,
 }
 
 impl fmt::Debug for UndefinedBehaviorInfo {
@@ -380,9 +388,18 @@ impl fmt::Debug for UndefinedBehaviorInfo {
  Ub(msg) | UbExperimental(msg) =>
  write!(f, "{}", msg),
  Unreachable =>
- write!(f, "entered unreachable code"),
+ write!(f, "entering unreachable code"),
  InvalidDiscriminant(val) =>
- write!(f, "encountered invalid enum discriminant {}", val),
+ write!(f, "encountering invalid enum discriminant {}", val),
+ BoundsCheckFailed { ref len, ref index } =>
+ write!(f, "indexing out of bounds: the len is {:?} but the index is {:?}",
+ len, index),
+ DivisionByZero =>
+ write!(f, "dividing by zero"),
+ RemainderByZero =>
+ write!(f, "calculating the remainder with a divisor of zero"),
+ PointerArithOverflow =>
+ write!(f, "overflowing in-bounds pointer arithmetic"),
  }
  }
 }

src/librustc/mir/interpret/pointer.rs

@@ -1,6 +1,5 @@
 use super::{AllocId, InterpResult};
 
-use crate::mir;
 use crate::ty::layout::{self, HasDataLayout, Size};
 
 use rustc_macros::HashStable;
@@ -88,13 +87,13 @@ pub trait PointerArithmetic: layout::HasDataLayout {
  #[inline]
  fn offset<'tcx>(&self, val: u64, i: u64) -> InterpResult<'tcx, u64> {
  let (res, over) = self.overflowing_offset(val, i);
- if over { throw_panic!(Overflow(mir::BinOp::Add)) } else { Ok(res) }
+ if over { throw_ub!(PointerArithOverflow) } else { Ok(res) }
  }
 
  #[inline]
  fn signed_offset<'tcx>(&self, val: u64, i: i64) -> InterpResult<'tcx, u64> {
  let (res, over) = self.overflowing_signed_offset(val, i128::from(i));
- if over { throw_panic!(Overflow(mir::BinOp::Add)) } else { Ok(res) }
+ if over { throw_ub!(PointerArithOverflow) } else { Ok(res) }
  }
 }
 

src/librustc_mir/interpret/operator.rs

@@ -177,8 +177,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
  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),
- Rem if r == 0 => throw_panic!(RemainderByZero),
+ Div if r == 0 => throw_ub!(DivisionByZero),
+ Rem if r == 0 => throw_ub!(RemainderByZero),
  Div => Some(i128::overflowing_div),
  Rem => Some(i128::overflowing_rem),
  Add => Some(i128::overflowing_add),
@@ -234,8 +234,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
  Add => u128::overflowing_add,
  Sub => u128::overflowing_sub,
  Mul => u128::overflowing_mul,
- Div if r == 0 => throw_panic!(DivisionByZero),
- Rem if r == 0 => throw_panic!(RemainderByZero),
+ Div if r == 0 => throw_ub!(DivisionByZero),
+ Rem if r == 0 => throw_ub!(RemainderByZero),
  Div => u128::overflowing_div,
  Rem => u128::overflowing_rem,
  _ => bug!(),

src/librustc_mir/interpret/place.rs

@@ -384,10 +384,8 @@ where
  layout::FieldPlacement::Array { stride, .. } => {
  let len = base.len(self)?;
  if field >= len {
- // This can be violated because the index (field) can be a runtime value
- // provided by the user.
- debug!("tried to access element {} of array/slice with length {}", field, len);
- throw_panic!(BoundsCheck { len, index: field });
+ // This can only be reached in ConstProp and non-rustc-MIR.
+ throw_ub!(BoundsCheckFailed { len, index: field });
  }
  stride * field
  }

src/test/compile-fail/consts/const-err3.rs

@@ -14,7 +14,6 @@ fn main() {
  //~^ ERROR const_err
  let _e = [5u8][1];
  //~^ ERROR const_err
- //~| ERROR this expression will panic at runtime
  black_box(b);
  black_box(c);
  black_box(d);

src/test/ui/consts/array-literal-index-oob.stderr

@@ -12,7 +12,7 @@ error: reaching this expression at runtime will panic or abort
 LL | &{[1, 2, 3][4]};
  | --^^^^^^^^^^^^-
  | |
- | index out of bounds: the len is 3 but the index is 4
+ | indexing out of bounds: the len is 3 but the index is 4
 
 error: aborting due to 2 previous errors
 

src/test/ui/consts/const-err2.rs

@@ -23,7 +23,6 @@ fn main() {
  //~^ ERROR const_err
  let _e = [5u8][1];
  //~^ ERROR index out of bounds
- //~| ERROR this expression will panic at runtime
  black_box(a);
  black_box(b);
  black_box(c);

src/test/ui/consts/const-err2.stderr

@@ -34,11 +34,5 @@ error: index out of bounds: the len is 1 but the index is 1
 LL | let _e = [5u8][1];
  | ^^^^^^^^
 
-error: this expression will panic at runtime
- --> $DIR/const-err2.rs:24:14
- |
-LL | let _e = [5u8][1];
- | ^^^^^^^^ index out of bounds: the len is 1 but the index is 1
-
-error: aborting due to 6 previous errors
+error: aborting due to 5 previous errors
 

src/test/ui/consts/const-err3.rs

@@ -23,7 +23,6 @@ fn main() {
  //~^ ERROR const_err
  let _e = [5u8][1];
  //~^ ERROR const_err
- //~| ERROR this expression will panic at runtime
  black_box(a);
  black_box(b);
  black_box(c);

src/test/ui/consts/const-err3.stderr

@@ -34,11 +34,5 @@ error: index out of bounds: the len is 1 but the index is 1
 LL | let _e = [5u8][1];
  | ^^^^^^^^
 
-error: this expression will panic at runtime
- --> $DIR/const-err3.rs:24:14
- |
-LL | let _e = [5u8][1];
- | ^^^^^^^^ index out of bounds: the len is 1 but the index is 1
-
-error: aborting due to 6 previous errors
+error: aborting due to 5 previous errors
 

src/test/ui/consts/const-eval/promoted_errors.rs

@@ -8,14 +8,12 @@ fn main() {
  //~^ ERROR const_err
  println!("{}", 1/(1-1));
  //~^ ERROR attempt to divide by zero [const_err]
- //~| ERROR reaching this expression at runtime will panic or abort [const_err]
+ //~| ERROR const_err
  let _x = 1/(1-1);
  //~^ ERROR const_err
- //~| ERROR const_err
  println!("{}", 1/(false as u32));
  //~^ ERROR attempt to divide by zero [const_err]
- //~| ERROR reaching this expression at runtime will panic or abort [const_err]
+ //~| ERROR const_err
  let _x = 1/(false as u32);
  //~^ ERROR const_err
- //~| ERROR const_err
 }

src/test/ui/consts/const-eval/promoted_errors.stderr

@@ -20,43 +20,31 @@ error: reaching this expression at runtime will panic or abort
  --> $DIR/promoted_errors.rs:9:20
  |
 LL | println!("{}", 1/(1-1));
- | ^^^^^^^ attempt to divide by zero
+ | ^^^^^^^ dividing by zero
 
 error: attempt to divide by zero
  --> $DIR/promoted_errors.rs:12:14
  |
 LL | let _x = 1/(1-1);
  | ^^^^^^^
 
-error: this expression will panic at runtime
- --> $DIR/promoted_errors.rs:12:14
- |
-LL | let _x = 1/(1-1);
- | ^^^^^^^ attempt to divide by zero
-
 error: attempt to divide by zero
- --> $DIR/promoted_errors.rs:15:20
+ --> $DIR/promoted_errors.rs:14:20
  |
 LL | println!("{}", 1/(false as u32));
  | ^^^^^^^^^^^^^^^^
 
 error: reaching this expression at runtime will panic or abort
- --> $DIR/promoted_errors.rs:15:20
+ --> $DIR/promoted_errors.rs:14:20
  |
 LL | println!("{}", 1/(false as u32));
- | ^^^^^^^^^^^^^^^^ attempt to divide by zero
+ | ^^^^^^^^^^^^^^^^ dividing by zero
 
 error: attempt to divide by zero
- --> $DIR/promoted_errors.rs:18:14
+ --> $DIR/promoted_errors.rs:17:14
  |
 LL | let _x = 1/(false as u32);
  | ^^^^^^^^^^^^^^^^
 
-error: this expression will panic at runtime
- --> $DIR/promoted_errors.rs:18:14
- |
-LL | let _x = 1/(false as u32);
- | ^^^^^^^^^^^^^^^^ attempt to divide by zero
-
-error: aborting due to 9 previous errors
+error: aborting due to 7 previous errors
 

src/test/ui/consts/const-eval/promoted_errors2.rs

@@ -9,14 +9,12 @@ fn main() {
  //~^ ERROR attempt to subtract with overflow
  println!("{}", 1/(1-1));
  //~^ ERROR attempt to divide by zero [const_err]
- //~| ERROR reaching this expression at runtime will panic or abort [const_err]
+ //~| ERROR const_err
  let _x = 1/(1-1);
  //~^ ERROR const_err
- //~| ERROR const_err
  println!("{}", 1/(false as u32));
  //~^ ERROR attempt to divide by zero [const_err]
- //~| ERROR reaching this expression at runtime will panic or abort [const_err]
+ //~| ERROR const_err
  let _x = 1/(false as u32);
  //~^ ERROR const_err
- //~| ERROR const_err
 }

src/test/ui/consts/const-eval/promoted_errors2.stderr

@@ -26,43 +26,31 @@ error: reaching this expression at runtime will panic or abort
  --> $DIR/promoted_errors2.rs:10:20
  |
 LL | println!("{}", 1/(1-1));
- | ^^^^^^^ attempt to divide by zero
+ | ^^^^^^^ dividing by zero
 
 error: attempt to divide by zero
  --> $DIR/promoted_errors2.rs:13:14
  |
 LL | let _x = 1/(1-1);
  | ^^^^^^^
 
-error: this expression will panic at runtime
- --> $DIR/promoted_errors2.rs:13:14
- |
-LL | let _x = 1/(1-1);
- | ^^^^^^^ attempt to divide by zero
-
 error: attempt to divide by zero
- --> $DIR/promoted_errors2.rs:16:20
+ --> $DIR/promoted_errors2.rs:15:20
  |
 LL | println!("{}", 1/(false as u32));
  | ^^^^^^^^^^^^^^^^
 
 error: reaching this expression at runtime will panic or abort
- --> $DIR/promoted_errors2.rs:16:20
+ --> $DIR/promoted_errors2.rs:15:20
  |
 LL | println!("{}", 1/(false as u32));
- | ^^^^^^^^^^^^^^^^ attempt to divide by zero
+ | ^^^^^^^^^^^^^^^^ dividing by zero
 
 error: attempt to divide by zero
- --> $DIR/promoted_errors2.rs:19:14
+ --> $DIR/promoted_errors2.rs:18:14
  |
 LL | let _x = 1/(false as u32);
  | ^^^^^^^^^^^^^^^^
 
-error: this expression will panic at runtime
- --> $DIR/promoted_errors2.rs:19:14
- |
-LL | let _x = 1/(false as u32);
- | ^^^^^^^^^^^^^^^^ attempt to divide by zero
-
-error: aborting due to 10 previous errors
+error: aborting due to 8 previous errors
 

src/test/ui/consts/const-prop-ice.rs

@@ -1,4 +1,3 @@
 fn main() {
  [0; 3][3u64 as usize]; //~ ERROR the len is 3 but the index is 3
- //~| ERROR this expression will panic at runtime
 }

src/test/ui/consts/const-prop-ice.stderr

@@ -6,11 +6,5 @@ LL | [0; 3][3u64 as usize];
  |
  = note: `#[deny(const_err)]` on by default
 
-error: this expression will panic at runtime
- --> $DIR/const-prop-ice.rs:2:5
- |
-LL | [0; 3][3u64 as usize];
- | ^^^^^^^^^^^^^^^^^^^^^ index out of bounds: the len is 3 but the index is 3
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 

src/test/ui/issues/issue-54348.rs

@@ -1,7 +1,5 @@
 fn main() {
  [1][0u64 as usize];
  [1][1.5 as usize]; //~ ERROR index out of bounds
- //~| ERROR this expression will panic at runtime
  [1][1u64 as usize]; //~ ERROR index out of bounds
- //~| ERROR this expression will panic at runtime
 }

src/test/ui/issues/issue-54348.stderr

@@ -6,23 +6,11 @@ LL | [1][1.5 as usize];
  |
  = note: `#[deny(const_err)]` on by default
 
-error: this expression will panic at runtime
- --> $DIR/issue-54348.rs:3:5
- |
-LL | [1][1.5 as usize];
- | ^^^^^^^^^^^^^^^^^ index out of bounds: the len is 1 but the index is 1
-
 error: index out of bounds: the len is 1 but the index is 1
- --> $DIR/issue-54348.rs:5:5
+ --> $DIR/issue-54348.rs:4:5
  |
 LL | [1][1u64 as usize];
  | ^^^^^^^^^^^^^^^^^^
 
-error: this expression will panic at runtime
- --> $DIR/issue-54348.rs:5:5
- |
-LL | [1][1u64 as usize];
- | ^^^^^^^^^^^^^^^^^^ index out of bounds: the len is 1 but the index is 1
-
-error: aborting due to 4 previous errors
+error: aborting due to 2 previous errors
 

src/test/ui/issues/issue-8460-const.rs

@@ -23,19 +23,14 @@ fn main() {
  //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1isize / 0; }).join().is_err());
  //~^ ERROR attempt to divide by zero
- //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1i8 / 0; }).join().is_err());
  //~^ ERROR attempt to divide by zero
- //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1i16 / 0; }).join().is_err());
  //~^ ERROR attempt to divide by zero
- //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1i32 / 0; }).join().is_err());
  //~^ ERROR attempt to divide by zero
- //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1i64 / 0; }).join().is_err());
  //~^ ERROR attempt to divide by zero
- //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { isize::MIN % -1; }).join().is_err());
  //~^ ERROR attempt to calculate the remainder with overflow
  //~| ERROR this expression will panic at runtime
@@ -53,17 +48,12 @@ fn main() {
  //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1isize % 0; }).join().is_err());
  //~^ ERROR attempt to calculate the remainder with a divisor of zero
- //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1i8 % 0; }).join().is_err());
  //~^ ERROR attempt to calculate the remainder with a divisor of zero
- //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1i16 % 0; }).join().is_err());
  //~^ ERROR attempt to calculate the remainder with a divisor of zero
- //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1i32 % 0; }).join().is_err());
  //~^ ERROR attempt to calculate the remainder with a divisor of zero
- //~| ERROR this expression will panic at runtime
  assert!(thread::spawn(move|| { 1i64 % 0; }).join().is_err());
  //~^ ERROR attempt to calculate the remainder with a divisor of zero
- //~| ERROR this expression will panic at runtime
 }