Fix layout with packed class that only has a vtable #1495
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I noticed that a `#pragma packed` class that has only a vtable but no data members is not marked repr(packed). The bug is that is_packed examines data members but not the vtable when applying its heuristic.
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emilio
approved these changes
Jan 18, 2019
| @@ -1517,6 +1517,10 @@ impl CompInfo { | |||
| }) { | |||
| info!("Found a struct that was defined within `#pragma packed(...)`"); | |||
| return true; | |||
| } else if self.has_own_virtual_method { | |||
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Should this really be an else condition?
Or should it be:
// ..
}
if self.has_own_virtual_method && parent_layout.align == 1 {
return 1;
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It passes either way, so I guess it doesn't really matter. A class without data members won't ever pass that first condition. I can reword it if you like.
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No, that's fine, I was wondering if this would allow catching stuff where we don't know the layout of the members because libclang doesn't expose it, yet we know we have a vtable. Anyhow this is fine.
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I noticed that a
#pragma packedclass that has only a vtable but nodata members is not marked repr(packed). The bug is that is_packed
examines data members but not the vtable when applying its heuristic.