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Tidy up calloc code

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This commit is contained in:
Tim Diekmann 2019-04-08 01:12:44 +02:00
parent d1d05c8b41
commit a59e155206
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GPG key ID: 58CD76F88DF563E0
1 changed files with 7 additions and 16 deletions
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23
src/fn_call.rs
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@ -95,25 +95,16 @@ pub trait EvalContextExt<'a, 'mir, 'tcx: 'a + 'mir>: crate::MiriEvalContextExt<'
}
"calloc" => {
let items = this.read_scalar(args[0])?.to_usize(this)?;
let count = this.read_scalar(args[1])?.to_usize(this)?;
let size = if let Some(size) = items.checked_add(count) {
size
} else {
return err!(MachineError(format!(
"calloc: overflow of items * count: {} * {}",
items, count,
)));
};
if size == 0 {
let len = this.read_scalar(args[1])?.to_usize(this)?;
let bytes = items.checked_mul(len).ok_or_else(|| InterpError::Overflow(mir::BinOp::Mul))?;
if bytes== 0 {
this.write_null(dest)?;
} else {
let size = Size::from_bytes(bytes);
let align = this.tcx.data_layout.pointer_align.abi;
let ptr = this.memory_mut()
.allocate(Size::from_bytes(size), align, MiriMemoryKind::C.into())
.with_default_tag();
this.memory_mut()
.get_mut(ptr.alloc_id)?
.write_repeat(tcx, ptr, 0, Size::from_bytes(size))?;
let ptr = this.memory_mut().allocate(size, align, MiriMemoryKind::C.into()).with_default_tag();
this.memory_mut().get_mut(ptr.alloc_id)?.write_repeat(tcx, ptr, 0, size)?;
this.write_scalar(Scalar::Ptr(ptr), dest)?;
}
}