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Add align_offset for integers

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This commit is contained in:
Christian Poveda 2019-09-16 13:46:37 -05:00
parent 55863cb88e
commit 881929f753
1 changed files with 30 additions and 19 deletions
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49
src/shims/mod.rs
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@ -27,25 +27,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
}
// There are some more lang items we want to hook that CTFE does not hook (yet).
if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
let n = {
let ptr = this.force_ptr(this.read_scalar(args[0])?.not_undef()?)?;
let align = this.force_bits(
this.read_scalar(args[1])?.not_undef()?,
this.pointer_size()
)? as usize;
let stride = this.memory().get(ptr.alloc_id)?.align.bytes() as usize;
// if the allocation alignment is at least the required alignment, we use the
// libcore implementation
if stride >= align {
((stride + ptr.offset.bytes() as usize) as *const ())
.align_offset(align) as u128
} else {
u128::max_value()
}
};
let n = this.align_offset(args[0], args[1])?;
let dest = dest.unwrap();
let n = this.truncate(n, dest.layout);
this.write_scalar(Scalar::from_uint(n, dest.layout.size), dest)?;
@ -65,4 +47,33 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
// Otherwise, load the MIR.
Ok(Some(this.load_mir(instance.def, None)?))
}
fn align_offset(
&mut self,
ptr_op: OpTy<'tcx, Tag>,
align_op: OpTy<'tcx, Tag>
) -> InterpResult<'tcx, u128> {
let this = self.eval_context_mut();
let req_align = this.force_bits(
this.read_scalar(align_op)?.not_undef()?,
this.pointer_size()
)? as usize;
let ptr_scalar = this.read_scalar(ptr_op)?.not_undef()?;
if let Scalar::Ptr(ptr) = ptr_scalar {
let cur_align = this.memory().get(ptr.alloc_id)?.align.bytes() as usize;
if cur_align < req_align {
return Ok(u128::max_value());
}
}
// if the allocation alignment is at least the required alignment or if the pointer is an
// integer, we use the libcore implementation
Ok(
(this.force_bits(ptr_scalar, this.pointer_size())? as *const i8)
.align_offset(req_align) as u128
)
}
}