[PATCH] D75270: [DebugInfo] Do not emit entry values for composite locations

Fri Feb 28 05:53:49 PST 2020

djtodoro added a comment.

In D75270#1897552 <https://reviews.llvm.org/D75270#1897552>, @dstenb wrote:

> In D75270#1897396 <https://reviews.llvm.org/D75270#1897396>, @djtodoro wrote:
>
> > > As far as I can tell GCC does not emit any
> > > entry values / call sites in these cases, so we do not have something to
> > > compare with, but the former seems like the more reasonable approach.
> >
> > I think as well. What about GDB side? Did GDB expect something like this? I though just running GDB over such case could be interesting to see if it accepts such scenario or not (I should find some time to play with that for sure).
>
>
> GDB currently imposes the following restrictions for call site locations:
>
>   Only single DW_OP_reg or DW_OP_fbreg is supported for DW_FORM_block* DW_AT_location is supported for DW_TAG_call_site child DIE
>
>
> and the following for entry value operations:
>
>   DWARF-2 expression error: DW_OP_entry_value is supported only for single DW_OP_reg* or for DW_OP_breg*(0)+DW_OP_deref*
>

Thanks for this! I've expected that... I've confirmed this output with an older version of //GDB 7.1*// as well. We will need to discuss about adding such support to debuggers.

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https://reviews.llvm.org/D75270