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Re: [PATCH 2/2] Involve gdbarch in taking DWARF register pieces
- From: Doug Evans <dje at google dot com>
- To: Pedro Alves <palves at redhat dot com>
- Cc: Andreas Arnez <arnez at linux dot vnet dot ibm dot com>, Ulrich Weigand <uweigand at de dot ibm dot com>, gdb-patches <gdb-patches at sourceware dot org>, Ulrich Weigand <Ulrich dot Weigand at de dot ibm dot com>
- Date: Mon, 18 Apr 2016 08:57:10 -0700
- Subject: Re: [PATCH 2/2] Involve gdbarch in taking DWARF register pieces
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- References: <20160415180943 dot 4FEE857EE at oc7340732750 dot ibm dot com> <571134CD dot 8080507 at redhat dot com> <m3shyjw2t3 dot fsf at oc1027705133 dot ibm dot com> <5714E6EA dot 8050905 at redhat dot com> <m3lh4bvu2z dot fsf at oc1027705133 dot ibm dot com> <57150356 dot 3090508 at redhat dot com>
On Mon, Apr 18, 2016 at 8:55 AM, Pedro Alves <palves@redhat.com> wrote:
> On 04/18/2016 04:02 PM, Andreas Arnez wrote:
>> On Mon, Apr 18 2016, Pedro Alves wrote:
>
>> OK. Now, reading this again, it seems to me that I should better add
>> the following disclaimer at the end:
>>
>> ... This method also applies when interpreting a register as a
>> LEN-sized type, except when convert_register_p indicates that a
>> special conversion is required instead.
>>
>> Still OK?
This is the part that I found lacking when I read the initial patch.
> Hmm, isn't "type" the other side of the same coin though?
>
> How about this:
>
> Determine the physical placement of a type of size LEN within register
> *REGNUM, possibly overwriting *REGNUM. (E.g., some ABIs lay vector
> types in registers pairs, and thus this method writes the correct pair
> element to *REGNUM). Returns the byte offset of the data within the
> (possibly adjusted) register. This method is used when determining
> the placement of a DWARF piece (DW_OP_piece), or when interpreting a
> register as a LEN-sized type, except when convert_register_p indicates
> that a special conversion is required instead.
SGTM
>>> I'd suggest even calling it "dwarf_register_piece_placement" for
>>> caller clarity?
>>
>> Sure, but I find a name like 'gdbarch_dwarf_register_piece_placement' a
>> bit too unwieldy when trying to stick to an 80 char line size limit.
>> Maybe 'gdbarch_register_piece_placement'?
>
> Deal. :-)
>
> Thanks,
> Pedro Alves
>