[Dwarf-Discuss] OP_fbreg within AT_frame_base, static or dynamic ?

Tristan Gingold gingold at adacore.com
Wed Mar 2 01:09:55 PST 2011


On Mar 1, 2011, at 5:55 PM, Roland McGrath wrote:

> DWARF in general is not so narrowly specified that this kind of issue falls
> into a "clearly valid" or "clearly invalid" category.  I think it is
> adequately unambiguous what that construct means, and that is usually good
> enough in the DWARF world.

Great, but these kinds of ambiguous meanings lead to incompatible tools.
(and in this particular case, this is easily fixable.  Maybe I can propose
 a change ?)

> A type is used in a particular context.  That is, it's the type of some
> object like a variable, and that object description exists in a context
> such as being local to a function.  When you use the type, you are using it
> in a specific context such as a given call frame.  A type such as this has
> details that are dependent on its call frame context, so it would be a
> dynamic error to attempt to use it without an associated call frame.
> Since it uses DW_OP_fbreg, it can only be used in the context of a call
> frame where DW_AT_frame_base is defined.

So, you agree to allow non-static context.

Thanks,
Tristan.




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