Miri: use more specialized Scalar::from_ constructors where appropriate #70508
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r? @varkor (rust_highfive has picked a reviewer for you, use r? to override) |
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| @@ -220,7 +222,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { | |||
| sym::discriminant_value => { | |||
| let place = self.deref_operand(args[0])?; | |||
| let discr_val = self.read_discriminant(place.into())?.0; | |||
| self.write_scalar(Scalar::from_uint(discr_val, dest.layout.size), dest)?; | |||
| self.write_scalar(Scalar::from_u64(u64::try_from(discr_val).unwrap()), dest)?; | |||
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@eddyb this is where Miri would now ICE for too big discriminants. (And I am not entirely sure what happens for negative discriminants, TBH...)
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Looking at this, I think for signed 64bit discriminants we appropriately truncate and everything is okay. (I tried to find a way to share that code there with cast.rs but found no good way.)
For negative discriminants with repr(i128) this will ICE, but well, these just cannot be represented properly in a u64...
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r? @eddyb |
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@bors r+ |
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📌 Commit bd9e046 has been approved by |
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Rollup of 5 pull requests Successful merges: - rust-lang#69937 (ASCII methods on OsStr) - rust-lang#70235 (Validate git setup before accessing functionality) - rust-lang#70503 (rename Scalar::{ptr_null -> null_ptr} and add "machine_" prefix like elsewhere) - rust-lang#70508 (Miri: use more specialized Scalar::from_ constructors where appropriate) - rust-lang#70510 (fix TryEnterCriticalSection return type) Failed merges: r? @ghost
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