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fix using copy_op to transmute

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This commit is contained in:
Ralf Jung 2018-08-16 09:36:44 +02:00
parent 23d86b0136
commit ad009ae73b
1 changed files with 10 additions and 8 deletions
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18
src/librustc_mir/interpret/place.rs
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@ -520,7 +520,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
trace!("write_value: {:?} <- {:?}", *dest, src_val);
// See if we can avoid an allocation. This is the counterpart to `try_read_value`,
// but not factored as a separate function.
match dest.place {
let mplace = match dest.place {
Place::Local { frame, local } => {
match *self.stack[frame].locals[local].access_mut()? {
Operand::Immediate(ref mut dest_val) => {
@ -528,14 +528,14 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
*dest_val = src_val;
return Ok(());
},
_ => {},
Operand::Indirect(mplace) => mplace, // already in memory
}
},
_ => {},
Place::Ptr(mplace) => mplace, // already in memory
};
// Slow path: write to memory
let dest = self.force_allocation(dest)?;
// This is already in memory, write there.
let dest = MPlaceTy { mplace, layout: dest.layout };
self.write_value_to_mplace(src_val, dest)
}
@ -565,7 +565,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
Value::ScalarPair(a_val, b_val) => {
let (a, b) = match dest.layout.abi {
layout::Abi::ScalarPair(ref a, ref b) => (&a.value, &b.value),
_ => bug!("write_value_to_ptr: invalid ScalarPair layout: {:#?}", dest.layout)
_ => bug!("write_value_to_mplace: invalid ScalarPair layout: {:#?}", dest.layout)
};
let (a_size, b_size) = (a.size(&self), b.size(&self));
let (a_align, b_align) = (a.align(&self), b.align(&self));
@ -591,8 +591,10 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
// Let us see if the layout is simple so we take a shortcut, avoid force_allocation.
let (src_ptr, src_align) = match self.try_read_value(src)? {
Ok(src_val) =>
// Yay, we got a value that we can write directly.
return self.write_value(src_val, dest),
// Yay, we got a value that we can write directly. We write with the
// *source layout*, because that was used to load, and if they do not match
// this is a transmute we want to support.
return self.write_value(src_val, PlaceTy { place: *dest, layout: src.layout }),
Err(mplace) => mplace.to_scalar_ptr_align(),
};
// Slow path, this does not fit into an immediate. Just memcpy.