avoid catching errors

Author: RalfJung

src/operator.rs

@@ -397,21 +397,24 @@ impl<'mir, 'tcx> EvalContextExt<'tcx> for super::MiriEvalContext<'mir, 'tcx> {
  .checked_mul(pointee_size)
  .ok_or_else(|| InterpError::Overflow(mir::BinOp::Mul))?;
  // Now let's see what kind of pointer this is.
- if let Ok(ptr) = self.force_ptr(ptr) {
- // Both old and new pointer must be in-bounds of a *live* allocation.
- // (Of the same allocation, but that part is trivial with our representation.)
- self.pointer_inbounds(ptr)?;
- let ptr = ptr.signed_offset(offset, self)?;
- self.pointer_inbounds(ptr)?;
- Ok(Scalar::Ptr(ptr))
- } else {
- // A "true" integer pointer. They can only be offset by 0, and we pretend there
- // is a little zero-sized allocation here.
- if offset == 0 {
- Ok(ptr)
- } else {
- err!(InvalidPointerMath)
+ let ptr = if offset == 0 {
+ match ptr {
+ Scalar::Ptr(ptr) => ptr,
+ Scalar::Raw { .. } => {
+ // Offset 0 on an integer. We accept that, pretending there is
+ // a little zero-sized allocation here.
+ return Ok(ptr);
+ }
  }
- }
+ } else {
+ // Offset > 0. We *require* a pointer.
+ self.force_ptr(ptr)?
+ };
+ // Both old and new pointer must be in-bounds of a *live* allocation.
+ // (Of the same allocation, but that part is trivial with our representation.)
+ self.pointer_inbounds(ptr)?;
+ let ptr = ptr.signed_offset(offset, self)?;
+ self.pointer_inbounds(ptr)?;
+ Ok(Scalar::Ptr(ptr))
  }
 }

tests/compile-fail/ptr_offset_int_plus_int.rs

@@ -1,4 +1,4 @@
-// error-pattern: invalid arithmetic on pointers
+// error-pattern: tried to interpret some bytes as a pointer
 
 fn main() {
  // Can't offset an integer pointer by non-zero offset.