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Early abort validation of arrays of zsts because there is no data to be checked

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This commit is contained in:
Oliver Scherer 2020-01-13 16:12:10 +01:00
parent 2d8d559bbe
commit 19b9b26986
1 changed files with 8 additions and 3 deletions
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11
src/librustc_mir/interpret/validity.rs
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@ -608,9 +608,14 @@ impl<'rt, 'mir, 'tcx, M: Machine<'mir, 'tcx>> ValueVisitor<'mir, 'tcx, M>
return Ok(()); return Ok(());
} }
// This is the element type size. // This is the element type size.
let ty_size = self.ecx.layout_of(tys)?.size; let layout = self.ecx.layout_of(tys)?;
// Empty tuples and fieldless structs (the only ZSTs that allow reaching this code)
// have no data to be checked.
if layout.is_zst() {
return Ok(());
}
// This is the size in bytes of the whole array. // This is the size in bytes of the whole array.
let size = ty_size * len; let size = layout.size * len;
// Size is not 0, get a pointer. // Size is not 0, get a pointer.
let ptr = self.ecx.force_ptr(mplace.ptr)?; let ptr = self.ecx.force_ptr(mplace.ptr)?;
@ -640,7 +645,7 @@ impl<'rt, 'mir, 'tcx, M: Machine<'mir, 'tcx>> ValueVisitor<'mir, 'tcx, M>
// Some byte was undefined, determine which // Some byte was undefined, determine which
// element that byte belongs to so we can // element that byte belongs to so we can
// provide an index. // provide an index.
let i = (offset.bytes() / ty_size.bytes()) as usize; let i = (offset.bytes() / layout.size.bytes()) as usize;
self.path.push(PathElem::ArrayElem(i)); self.path.push(PathElem::ArrayElem(i));
throw_validation_failure!("undefined bytes", self.path) throw_validation_failure!("undefined bytes", self.path)