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strictly enforce pointer validity even for zero-sized accesses

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This commit is contained in:
Ralf Jung 2018-08-30 10:50:13 +02:00
parent 752accf4e4
commit fe9cd1c98d
1 changed files with 13 additions and 21 deletions
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34
src/intrinsic.rs
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@ -179,21 +179,17 @@ impl<'a, 'mir, 'tcx> EvalContextExt<'tcx> for EvalContext<'a, 'mir, 'tcx, super:
let elem_layout = self.layout_of(elem_ty)?;
let elem_size = elem_layout.size.bytes();
let count = self.read_scalar(args[2])?.to_usize(&self)?;
if count * elem_size != 0 {
// TODO: We do not even validate alignment for the 0-bytes case. libstd relies on this in vec::IntoIter::next.
// Also see the write_bytes intrinsic.
let elem_align = elem_layout.align;
let src = self.read_scalar(args[0])?.not_undef()?;
let dest = self.read_scalar(args[1])?.not_undef()?;
self.memory.copy(
src,
elem_align,
dest,
elem_align,
Size::from_bytes(count * elem_size),
intrinsic_name.ends_with("_nonoverlapping"),
)?;
}
let elem_align = elem_layout.align;
let src = self.read_scalar(args[0])?.not_undef()?;
let dest = self.read_scalar(args[1])?.not_undef()?;
self.memory.copy(
src,
elem_align,
dest,
elem_align,
Size::from_bytes(count * elem_size),
intrinsic_name.ends_with("_nonoverlapping"),
)?;
}
"discriminant_value" => {
@ -563,12 +559,8 @@ impl<'a, 'mir, 'tcx> EvalContextExt<'tcx> for EvalContext<'a, 'mir, 'tcx, super:
let val_byte = self.read_scalar(args[1])?.to_u8()?;
let ptr = self.read_scalar(args[0])?.not_undef()?;
let count = self.read_scalar(args[2])?.to_usize(&self)?;
if count > 0 {
// HashMap relies on write_bytes on a NULL ptr with count == 0 to work
// TODO: Should we, at least, validate the alignment? (Also see the copy intrinsic)
self.memory.check_align(ptr, ty_layout.align)?;
self.memory.write_repeat(ptr, val_byte, ty_layout.size * count)?;
}
self.memory.check_align(ptr, ty_layout.align)?;
self.memory.write_repeat(ptr, val_byte, ty_layout.size * count)?;
}
name => return err!(Unimplemented(format!("unimplemented intrinsic: {}", name))),