[Dwarf-discuss] Additional values for DW_AT_accessibility

[Martin]

On 25/09/2026 19:12, Ben Woodard via Dwarf-discuss wrote:
> 
> However, one thing that I am not really clear about in DWARF is does 
> DW_ACCESS_private have a specific semantic meaning independent of the 
> language. If it does, then it is not specified. I can see it two 
> different ways:
> 
> DW_ACCESS_private has a semantic meaning in DWARF separate from the 
> language. In that case because the FreePascal concept of "strict 
> private" maps more closely to C++'s concept of "private" which is 
> translated in DWARF into DW_ACCESS_private, "strict private" should map 
> to DW_ACCESS_private.
> 
> If we do this then I think we need to more clearly define what the 
> implied semantics of the Accessibility codes mean and do it in such a 
> way that it is independent of any language.
> 
> The other way that I can see it is DWARF acts as a mapping between the 
> source language and the machine language and is interpreted by the 
> consumer only in the context of the the language that the code was 
> written in. In that case, it is the language that provides the semantic 
> meaning of what the Accessibility Declaration means. That would lead to 
> DW_ACCESS_private mapping to the (module) private keyword in the 
> language. Strict private mapping to "DW_OP_strict_private"...
> 
> This would require more of the consumers. For example: libabigail would 
> have to understand the difference between "DW_ACCESS_private" as it 
> applies to C++ and how it applies to FreePascal.
> 
Just to add some info, in case it may help with that decision.

There likely will be some need of knowing the language to get the 
correct mapping.

E.g. Delphi/FreePascal has "type/class helpers". Those are kind-of 
dataless classes, that can be used to
- provide methods for another class
- access protected (but not private) data across unit boundaries.

They aren't an inherited class, more like a combination of interface and 
friend.

But unlike (afaik?) a C++ friend, it only has (cross unit) access to 
protected, not private methods/data.

So, if FPC where to declare them as friend, then the rules of what is 
accessible would be different from C++.