[Bug debug/53927] wrong value for DW_AT_static_link

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53927

--- Comment #23 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> The offset between the CFA and e FRAME object is now 0x90 bytes. So
> because of alignment constraints, I think we cannot assume we can have a
> constant offset (even function-dependent).
> 
> This offset is dynamic and the only way to compute it is to use the
> frame's context: here, nestee's saved registers, which we don't have
> access to in DWARF when computing the static link attribute.

OK, thanks for the investigation, the counter-example is quite telling and puts
an end to this approach.  To rescue some of this work, you could add a line to
the comment in the finalize_nesting_tree_1 hunk, explaining that we need to go
through the BUILT_IN_DWARF_CFA indirection because the offset of the FRAME
object in the stack frame can be dynamic if the FRAME object needs to be more
aligned than the stack.